BIODIESELSTUDY THE EFFECT OF DRY VS. WET WASHING ON ENERGY CONSUMPTION AND OPERATING COST AT DIFFERENT SOLVENT RATIOS

CHG-4300

Prepared by: Parag B. KadakiaStudent ID: 4332788

Session: Fall 2008

Professor: Dr. Andre Y. Tremblay

Department of Chemical EngineeringUniversity of OttawaOttawa, ON. Canada

AbstractSearch for renewable fuels are escalating due to the rising concern of CO2 emission.

Biodiesel is one such carbon neutral source of fuel becoming popular. High cost of

manufacturing biodiesel and limitations due to cold flow properties makes it a less favourite

renewable fuel. Therefore, the purpose of this study was to assess the possibility of reducing

energy consumption and thereby, increasing profit by implementing dry washing (ion exchange)

of crude biodiesel instead of water washing at different solvent to oil molar ratios.

Both the processes (water washed and dry washed) were simulated in HYSYS at six

different solvent to oil molar ratios (6:1, 9:1, 12:1, 15:1, 18:1, and 20:1). Preliminary equipment

design was carried out from material balance data derived from HYSYS and fixed cost was

estimated to be $10.15 m for water washed process and $ 7.52 m for dry washed process at 6:1

methanol to oil molar ratio. Energy consumption, after preliminary heat integration, was

estimated to be 3390 MJ/h for water washed and 1024 MJ/h for dry washed processes at the

same ratio. Operating cost of the plant for both processes were estimated and found to be $

53.08 m and $ 52.16 m for water washed and dry washed processes respectively.

It was found that the absence of water in the system reduces equipment cost because

methanol-water recovery and recycle is energy intensive process requiring additional equipment

such as- distillation column, reboiler and a condenser. For dry washed process, methanol can be

flash separated from glycerol but the ion exchange resin and tower are required to purify crude

biodiesel which incurs additional cost of $ 370,000. Vapour re-compression cycle was

implemented for methanol separation stage in dry washed process to conserve 12% of the

overall heat energy requirement.

The net profit generated by water washed process is in the range of $ 3.4 to 0.98 m

whereas by dry washed process is $4.3 to 3.7 m for ratios ranging from 6:1 to 20:1. Additional

profit in dry washed process clearly represents the savings due to decrease in energy

consumption when compared with water washed process. Therefore, dry washed process is

preferred over water washed process even at increased methanol to oil molar ratio of 20:1.

Some challenges were also identified such as- consumption of vegetable oils for biodiesel

production may create food crisis, higher crystallization temperature limits the use of biodiesel

and the price of vegetable oils is the major limiting factor in biodiesel profitability.

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Contents

I. Abstract..................................................................................................................................2

II. List of Figures.......................................................................................................................4

III. List of Tables.........................................................................................................................4

1.0 Introduction..................................................................................................................................51.1 History.......................................................................................................................61.2 Definition.......................................................................................................................6

1.3 Transesterification of oils and fats....................................................................71.4 Advantages and disadvantages of biodiesel......................................................8

2.0 Literature Review....................................................................................................................112.1 Choice of the catalyst........................................................................................112.2 Effect of methanol to oil molar ratio...............................................................122.2 Washing of crude biodiesel...............................................................................132.4 Effect of reaction temperature...................................................................................15

3.0 Process Description........................................................................................................17 3.1 Design basis........................................................................................................173.2 Typical process for water washing..................................................................183.3 Proposed process without water washing.......................................................20

4.0 Energy consumption......................................................................................................234.1 Vapour re-compression................................................................................................23

5.0 Cost Analysis.............................................................................................................................285.1 Fixed Cost Index (FCI).....................................................................................28

5.1.1 Water Washing......................................................................................285.1.2 Dry washing (ion exchange)..................................................................31

5.2 Cost of Manufacturing (COM).........................................................................335.2.1 Direct Manufacturing Cost (DMC)......................................................335.2.2 Fixed Manufacturing Cost (FMC)........................................................365.2.3 General Manufacturing Expenses (GE)...............................................37

5.3 Revenue generated.............................................................................................38

6.0 Conclusion and Recommendations..............................................................................406.1 Conclusion..........................................................................................................406.2 Recommendations..............................................................................................41

6.2.1 Vegetable oils- part of the food chain..................................................41

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6.2.2 Expensive Raw material........................................................................416.2.3 Cold flow properties..............................................................................42

6.2.4 Less incentive (profit margin)...............................................................43

7.0 References......................................................................................................................447.1 Web references..................................................................................................46

Appendix-I.....................................................................................................................47

II List of Figures

2.1 Wash water required to remove NaOH/HCl from biodiesel stream...........................142.2 Effect of temperature on biodiesel yield and reaction time..............................163.1 Process flow diagram for biodiesel production (Haas et al., 2006)..................183.2 Process flow diagram for biodiesel production (no washing)...........................213.3 HYSYS simulation of biodiesel production........................................................224.1 Comparison for energy consumption between

washing and no-washing options........................................................................244.2 Schematics for vapour re-compression for no-washing option.......................254.3 Methanol recovery and power consumption as a function of operating

pressure.................................................................................................................264.4 Comparison of energy consumption between vapour re-compression and no-

washing cycles for methanol separation stage...............................................................275.1 Equipment cost break up for 6:1 molar ratio washing option (Appendix-I).............315.2 Cost of manufacturing Distribution (6:1 ratio washing option).................................385.3 Net profit at different molar ratios.................................................................................39

III List of Tables

1.1 Advantages of biodiesel..........................................................................................81.2 Major disadvantages of biodiesel..........................................................................93.1 Feed and product flow rates................................................................................174.1 Nett heating required after integration (washing option- 6:1 molar ratio)....234.2 Nett cooling required after integration (washing option- 6:1 molar ratio)....234.3 Nett heating required after integration (no washing option- 6:1 ratio)..........234.4 Nett cooling required after integration (no washing option- 6:1 ratio)..........245.1 Fixed cost of the plant excluding land (6:1 molar ratio, wet washing)......................295.2 Fixed cost of the plant excluding land (6:1 molar ratio, dry washing)......................315.3 Grass route cost of equipment for different molar ratios...........................................325.4 Break up for yearly raw material cost..........................................................................335.5 Utilities cost break up for 6:1 molar ratio....................................................................34

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5.6 Other Costs (6:1 ratio washing option).........................................................................36

5.7 Fixed manufacturing cost (FMC) (6:1 ratio washing option)....................................375.8 General manufacturing cost (GE) (6:1 ratio washing option)...................................37

1.0 Introduction

With the rising concern of global warming and thus green house gas (GHG) emission,

mainly caused by the combustion of limited quantity of fossil fuel, the need for exploring

renewable sources of energy has been increasing rapidly. On the other hand, biomass use is

becoming more popular due to its sort span of life cycle which makes it a carbon-neutral source

(Dowaki et al., 2007). Biodiesel is one such renewable fuel made from biomass used for diesel

engines and compression-ignition engines (CIGs).

Biodiesel is briefly defined as the monoalkyl esters of vegetable oils or animal fats.

Biodiesel is the best candidate for diesel fuels in diesel engines because it burns like petroleum

diesel with better efficiency than gasoline. Biodiesel also exhibits great potential for CIGs.

Biodiesel is now mainly being produced from soybean, canola, rapeseed, and palm oils. The

higher heating values (HHVs) of biodiesels are relatively high. The HHVs of biodiesels (39 to 41

MJ/kg) are slightly lower than those of gasoline (46 MJ/kg), or petroleum diesel (43 MJ/kg), but

higher than coal (32 to 37 MJ/kg) (Sheehan et al., 1998).

One of the most popular ways of manufacturing biodiesel is by trans-esterification of

vegetable oils as discussed in detail in Section1.3. The reaction requires higher then theoretically

required solvent to oil ratio and water washing of biodiesel. Separation and recycle of these

liquids in the process are energy intensive and require additional equipment. Therefore, the

purpose of this report is to study the effect of varying solvent to oil ratio and removing water

washing step on overall energy consumption and the operating cost of biodiesel manufacturing

facility.

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Literature review was done (Section 2.0) in order to form the design basis required to

compare with the proposed modifications in biodiesel manufacturing.

1.1 History

Although, the process of making fuel from biomass is as old as it can be e.g. burning of

wood, dried cow dumping etc. is still in practise in India since ancient times, biodiesel dates back

to 1853 when Duffy and Patrick attempted trans-esterification of triglycerides content in

vegetable oils and in animal fats. During 1893, the name “biodiesel” had been given to trans-

esterified vegetable oil to describe its use as a diesel fuel (Demirbas et al., 2002) in diesel

engines invented by German scientist Dr. Rudolph Diesel.

Since the 1980s, biodiesel plants have opened in many European countries, and some

cities have run buses on biodiesel, or blends of petro and biodiesels. In 1991, the European

Community (EC) proposed a 90% tax deduction for the use of biofuels, including biodiesel.

Biodiesel plants are now being built by several companies in Europe; each of these plants will

produce up to 1.5million gallons of fuel per year. The European Union accounted for nearly 89%

of all biodiesel production worldwide in 2005.

1.2 Definition

In general terms, biodiesel may be defined as a domestic, renewable fuel for diesel

engines derived from natural oils like soybean oil that meets the specifications of ASTM D 6751.

In technical terms (ASTM D 6751) biodiesel is a diesel engine fuel comprised of monoalkyl

esters of long-chain fatty acids derived from vegetable oils or animal fats, designated B100 and

meeting the requirements of ASTM D 6751(Demirbas et al., 2009). Biodiesel, also referred to as

methyl ester or fatty acid methyl ester (FAME), in application as an extender for combustion in

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CIEs (diesel), possesses a number of promising characteristics, including reduction of exhaust

emissions (Dunn et al., 2001).

1.3 Trans-esterification of oils and fats

In order for vegetable oils and fats to be compatible with the diesel engine, it is necessary to

reduce their viscosity. This can be accomplished by breaking down triglyceride bonds, with the

final product being referred to as biodiesel. There are at least four ways in which oils and fats

can be converted into biodiesel (Ghadge and Raheman et al., 2006):

1. Tran-sesterification,

2. Blending,

3. Microemulsions,

4. Pyrolysis.

Among these processes, trans-esterification is the most commonly used method. The trans-

esterification process is achieved by reaction of a triglyceride molecule with an excess of alcohol

in the presence of a catalyst to produce glycerine and a fatty acid methyl ester ‘‘FAME’’ which

is the biodiesel.

As shown in Figure 1.2, trans-esterification reaction consists of a sequence of three

consecutive reversible reactions where triglycerides are converted to diglycerides and then

diglycerides are converted to monoglycerides followed by the conversion of monoglycerides to

glycerol. In each step an ester is produced and thus three ester molecules are produced from one

molecule of triglycerides.

The transesterification reaction requires a catalyst such as sodium hydroxide to split the oil

molecules and an alcohol (methanol or ethanol) to combine with the separated esters. It also

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gives glycerol as a co-product which has a commercial value. A catalyst is usually used to

improve the reaction rate and yield (Demirbas et al., 2009). Because the reaction is reversible,

excess alcohol is used to shift the equilibrium to the product side.

1.4 Advantages and disadvantages of biodiesel

Some of the advantages of biodiesel are listed in Table 2.1. One of the major advantage

of biodiesel is that it is a renewable source of energy i.e. amount of carbon dioxide it emits upon

combustion is captured by the materials used to produce biodiesel and therefore, carbon dioxide

emission to atmosphere is negligible. Also, its low sulphur content (Knothe et al., 2006) is very

important property because, upon combustion, the sulphur content in the fuel gets oxidised to

form oxides of sulphur which stays in atmosphere and further reacts with water vapours present

in air to form sulphuric acid which is the major cause of acid rain. Biodiesel is more

biodegradable then petroleum diesel (Zhang et al., 2003) which is to decompose and does not

stay in the environment for a longer period.

Table 1.1 Advantages of biodiesel Portability Readily available Renewability High combustion efficiency and low sulfur and aromatic content. Higher cetane number, and higher biodegradability Helps reduce a country’s dependency on imported petroleum,

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The use of biodiesel is however limited despite its significant environmental benefits.

Table 2.2 lists some of the disadvantages of biodiesel. Operating disadvantages of biodiesel in

comparison with petrodiesel are cold start problem, lower energy content, higher copper strip

corrosion, and fuel pumping difficulty due to higher viscosity.

The major disadvantage of biodiesel is its high crystallization temperature (cold flow

properties) due to its saturated fatty acid content. various methods are applied to improve the

cold flow properties such as; by mixing with petroleum diesel fuel, by elimination of methyl

esters of saturated fatty acids with high crystallization temperature through chemical

combinations into stable solid compounds, or by winterization process (using solvent) or dry

fractionation (without solvent). However, according to some authors (Srivastava et al., 2008),

there is no reason to eliminate saturated methyl esters from biodiesel fuel, since it possesses

better properties related to ignition quality and calorific value (Kazancev et al., 2006). Another

approach could be to convert saturated fatty acid into unsaturated ones by applying acid

treatment.

Table 1.2 Major disadvantages of biodiesel.....

Higher viscosity. Lower energy content. Higher cloud and pour points. Higher NOx emission. Higher price. Cold start problems.

Low energy content of biodiesel increases fuel consumption when biodiesel is used

instead of pure petroleum diesel, in proportion to the share of the biodiesel content. Taking into

account the higher production value of biodiesel as compared to petroleum diesel, this increase

in fuel consumption raises in addition the overall cost of application of biodiesel as an alternative

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to petroleum diesel. Biodiesel has a higher cloud point and pour point compared to conventional

diesel (Prakash, 1998). Neat biodiesel and biodiesel blends increase nitrogen oxide (NO2)

emissions compared with petroleum-based diesel fuel used in an unmodified diesel engine (EPA,

2002). Peak torque is lower for biodiesel than petroleum diesel but occurs at lower engine speed

and generally the torque curves are flatter. Biodiesels on average decrease power by 5%

compared to diesel at rated loads (Demirbas et al., 2006).

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2.0 Literature Review

2.1 Choice of the catalyst

Alkaline catalysts are the preferred choice for the trans-esterification reaction because it

increases the rate of reaction which, otherwise, could last up to many hours. However, the

alkaline-catalyzed process is sensitive to FFA content of the feedstock oils. Many published

papers [9–11] suggested that alkaline catalysts could only be applied when FFA content in the

oils or fats is less than 1.0% (Leung et al., 2006). Three alkaline catalysts viz. sodium hydroxide

(NaOH), potassium hydroxide (KOH) and sodium methoxide (CH3ONa), are the most common

choices. Leung et al., 2006 studied the effects of these three catalysts used on the

transesterification through examining the ester content in the biodiesel. As shown in the Table

2.1, the amount of NaOH used was smaller than those of KOH and CH3ONa for the same mass

feedstock oil, since NaOH has the smallest molar mass (40 g/ mol), followed by CH3ONa (54

g/mol) and KOH (56 g/mol).

Table 2.1 Comparison of alkaline catalysts used in trans-esterification reaction (Leung et al., 2006)Catalyst Concentration

(wt% by weight of crude oil)

Ester content

(wt%)

Biodiesel yield

(wt%)

NaOH 1.1 94.0 85.3

KOH 1.5 92.5 86.0

CH3ONa 1.3 92.8 89.0

However, in terms of molar concentrationCH3ONa was about 10% lesser than that of

NaOH and KOH. Moreover, the biodiesel yields with NaOH and KOH as catalyst were lower

than that of CH3ONa. This happens because during the preparation of the catalyst NaOH (or

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KOH) will be added and dissolved in the anhydrous methanol forming sodium (or potassium)

methoxide together with a small amount of water.

Therefore, NaOH is selected as compared to KOH because it is cheaper and easily

available.

2.2 Effect of methanol to oil molar ratio

Methanol was chosen to be the solvent because methanol has the lowest boiling point and

least specific heat as compared to ethanol and butanol. Theoretically, 3moles of methanol are

required for each mole of oil but since the reaction is reversible, it is necessary to maintain

reactant concentration higher than product concentration in the reactor. Also, it is important to

get complete conversion of the oil because the mono, di and tri-glycerides cannot be washed with

water and they end up in the final product (Kotrba et al., 2006). When the trans-esterification is

complete, there should be no or only small traces of monoglycerides and only a small amount of

diglycerides in the reaction product stream (Vicente et al. 2004; Gerpen et al. 2004; Leung and

Guo 2006).

Leung et al., 2006 also conducted experiments to study the effect of molar ratio on ester

content and yield of the transesterification for canola oil. Maximum ester yield was obtained at a

molar ratio of 6:1 for neat Canola oil. This higher molar ratio than the stoichiometric value

resulted in a greater ester conversion and could ensure complete reaction. When the ratio was

increased from 3:1 to 6:1, the ester content raised from 80.3% to 98.0%, while the yield rose

from 78.7% to 90.0%. Therefore, the reaction was incomplete for a molar ratio less than 6:1. On

the other hand, there is very little effect on the biodiesel yield and purity for molar ratio beyond

6:1. The results showed that the molar ratio of alcohol to oil is another important parameter

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affecting the biodiesel yield and biodiesel purity, apart from catalyst concentration and reaction

time (Myint et al., 2009).

As stated above, a 6:1 methanol/oil molar ratio was optimal for the trans-esterification of neat

Canola oil. It resulted in the highest ester content in the product (98%) and maximum product

yield (90.4%). This result is in line with the reports of many investigations based on neat

vegetable oils (Dube et al., 2003, Freedman et al., 1984, Boocock et al., 1996), and this ratio has

actually been normally adopted in commercial operations.

2.3 Washing of crude biodiesel

There are two generally accepted methods to purify biodiesel: wet and dry washing. The more

traditional wet washing method is widely used to remove excess contaminants and left over

production chemical from biodiesel. In the biodiesel production, it is well known that the

vegetable oils/fats used as a raw material for the transesterification should be water-free since the

presence of water has negative effects on the reaction (Komers et al., 2001) and it also increases

the cost and production time. Dry washing replaces water with an ion exchange resin or

amagnesium silicate powder to neutralize impurities. Both dry washing methods are being used

in industrial plants (Gonzalez et al., 2003). Whilst it has been proved for some time that it is

possible to meet the specifications by water washing, this process gives rise to

some disadvantages. A highly polluting liquid effluent is generated as it is shown in Table 2.

Significant product loss can be carried out for retention in thewater phase. Furthermore,

emulsions formation when processing used cooking oils or other feeds with high FFA content

can happen due to the soap formation (Leung et al., 2001).

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Water is the main cause for side reactions besides alcoholysis – saponification of the

trans-esterified oil and/or alkyl esters produced. Therefore it is also responsible for the reduction

in the concentration of the catalyst.

Water can consume the catalyst and reduce catalyst efficiency (Komers et al., 2001). The

presence of water has a greater negative effect than that of the free fatty acids. So, the water

content should be kept below 0.06% (Ma et al., 1998), much lower than the allowable free fatty

acids content. Only as little as 0.1% of water added led to some reduction of the yield of methyl

esters and the conversion was significantly reduced to 6% when only 5% of water was added

(Canakci and Gerven et al., 1999). These problems may hinder the most efficient utilization of

waste vegetable oils and crude oils since they generally contain water and free fatty acids

(Tomasevic and Marinkovic, 2003).

Therefore, the proposed study also compares the effect of both, dry and wet, washing on energy

consumption and operating cost of the biodiesel plant. The quantity of water required was

assumed from Figure 2.1 (Myint et al., 2009).

Figure 2.1 Wash water required to remove NaOH/HCl from biodiesel stream (Myint et al., 2009)

In order to decrease the amount of NaOH and HCl in the product stream, water washing is used

along with adiabatic decantation. It can be seen that the amount of NaOH and HCl in the

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biodiesel stream decreases significantly as the amount of water used in the washing process

increases. However, after it reaches 300 mol of water, the catalyst amount removed from the

biodiesel stream becomes less significant. Therefore, 300 mol of water is considered to be the

practical amount of water needed for the washing step.

2.4 Effect of reaction temperature

In general, higher temperatures increases rate of reaction and reduces conversion. But

higher temperature could also accelerate the saponification of triglycerides affecting negatively

the product yield. On the other hand, higher temperature could lead to a drastic decrease in

viscosity which is favourable to increase the solubility of the oil in the methanol and improve the

contact between oil and methanol molecules, thereby reaching a better conversion of

triglycerides.

Therefore, the optimum reaction temperature has to be found. Leung et al., 2006

conducted experiments to determine the effect of reaction temperature on methyl esters

formation by carrying out trans-esterification reaction was carried out keeping 6:1 methanol/oil

molar ratio and 1.0 wt% NaOH concentration for neat oil. The experiments were conducted at

temperatures ranging from 30 to 70 °C. The effect of reaction temperature on the product yield

and reaction time is shown in Figure 2.2.

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Figure 2.2 Effect of temperature on biodiesel yield and reaction time (Leung et al., 2006)

Experimental results showed that the trans-esterification reaction could proceed within

the temperature range studied but the reaction time to complete the reaction varied significantly

with reaction temperature. It can be seen that a high product yield could be achieved even at

room temperature but the reaction time would be substantially increased. It was also observed

that for neat oil the maximum yield occurred at a lower temperature range between 40 and 45 °C.

When temperature was reduced from 70 °C to 45 °C, the product yield can be increased from

90.4% to 93.5%, enhanced by about 3%, but the reaction time for completion of the trans-

esterification was prolonged from 15 min to 60 min due to a lower reaction rate at 45 °C. This

significant increase in ester yield at a lower temperature indicated that higher temperature had a

negative impact on the product yield for the trans-esterification of neat oil. The reason for this is

that higher temperature accelerates the side saponification reaction of triglycerides. But,

obviously, the temperature effect was smaller than that of catalyst concentration.

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3.0 Process Description

3.1 Design basis

As stated earlier, two scenarios were considered; one with water washing (wet washing)

and another without water washing (dry washing) while methanol to oil molar ratios were varied

from 6:1 to 20:1 for each scenarios.

The process plant is designed for 10.5 million gallons of biodiesel per year (39,800 m3/year)

based on 8,000 operating hours/year. Input data of the feed and product flow rates are shown in

the Table 3.1.

Table 3.1 Feed and product flow rates

Mass flow (kg/h) Molar flow (kmol/h)

Canola oil 4260.00 4.81

Methanol (for 6:1 ratio) 924.88 28.86

NaOH 42.60 1.07

HCl 38.57 1.06

Biodiesel 4260.00 14.43

Glycerol 443.10 4.81

Water for washing 540.00 300.00

Water formation 26.59 1.48

It was also assumed that all the free fatty acid will react with NaOH and form soap. In order to

account for the presence of free fatty acids in the feedstock, 0.05 wt% of free fatty acid [oleic

acids (C18H34O2)] in the feed was assumed. This number corresponds to maximum amount of free

fatty acid in refined vegetable oil (Gerpen et al., 2005).

According to the previous assumptions, there is soap formation from both fatty acid

saponification and triglyceride saponification. A strong acid is added to reverse the

saponification process and prevent soap interference in the separation process. In this process,

hydrochloric acid is used to reverse soap formation and obtain free fatty acids and sodium

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chloride. HCl- the amount of hydrochloric acid required for neutralization is equivalent to the

number of moles of NaOH remaining in the mixture, which is 1.06 kmol/h.

3.2 Typical process for water washing

Figure 3.1 shows the PFD for biodiesel production. Three sequential trans-esterification

reactions were modeled. The first reactor was continuously fed with canola oil and a 1.78%

(wt/wt) solution of sodium methoxide in commercial grade methanol.

Figure 3.1 Process flow diagram for biodiesel production (Haas et al., 2006)

Product was removed from the reactor at a rate equal to the rate of charging with reactants and

catalyst in such a manner as to give a residence time of 1 h in the reactor. Glycerol, a co-product

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of trans-esterification, separates from the oil phase as the reaction proceeds. Following the first

trans-esterification reaction, continuous centrifugation is employed to remove the glycerol-rich

co-product phase, which is sent to the neutralizer. The methyl ester stream which also contains

un reacted methanol, oil and catalyst, is fed into a second steam jacketed, CSTR where a

continuous stirred reaction is conducted at 60oC, with the crude ester product being removed

from the reactor at a rate equal to that of reagent addition and in such fashion as to produce a

reactor residence time of 1 h. A trans-esterification efficiency of 90%, well within the range of

reported values (Freedman et al., 1984; Noureddini and Zhu, 1997), was assumed for each of

these three trans-esterification reactions, for an overall efficiency of 99%. The mixture of methyl

esters, glycerol, unreacted substrates and catalyst exiting the third CSTR reactor was fed to a

continuous decanter. The glycerol-rich aqueous stream from this operation is sent to the

neutralizer while the impure methyl ester product goes to the water wash tank for purification

and dehydration. The crude methyl ester stream is washed with water at pH 4.5 to neutralize the

catalyst and convert any soaps to free fatty acids, reducing their emulsifying tendencies. Then

biodiesel is separated from the aqueous phase in the decanter-2. The latter is cycled to the

neutralizer. The crude, washed methyl ester product may contain several percent of water. This

must be lowered to a maximum of 0.050% (v/v) to meet United States biodiesel specifications.

Water is removed in the evaporator from an initial value of 2.4% to a final content of 0.045%.

The glycerol liberated during trans-esterification has substantial commercial value if purified to

USP grade. However, this process is expensive. Small and moderately sized operations,

including those of the scale modeled here, often find it most cost effective to partially purify the

glycerol, removing methanol, fatty acids and most of the water, and selling the product (90%

glycerol by mass) to industrial glycerol refiners. This impure, dilute, aqueous glycerol streams

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exiting the trans-esterification reactors and the biodiesel wash process are treated with

hydrochloric acid to convert contaminating soaps to free acids, allowing removal by

centrifugation. This fatty acid waste is presumed to be destined for disposal. Methanol is

recovered from this stream by distillation and is recycled into the trans-esterification operation.

Finally, the diluted glycerol stream is distilled to reduce its water content. At this point the

glycerol concentration is 90% (w/w), suitable for sale into the crude glycerol market. Water

recovered during drying of the ester and glycerol fractions is recycled into wash operations. The

model includes maximum recovery of the heat present in condensates, transferring it via heat

exchangers to the material feed streams entering reactors. Since environmental pollution

regulations vary from location to location, no precise calculation of waste stream treatment costs

was attempted. However, the lump sum of $500,000 was allocated for waste stream disposal

charges.

3.3 Proposed process without water washing

Figure 3.2 shows the proposed PFD for no washing (ion exchange) process. The trans-

esterification step remains unchanged while crude biodiesel stream is directly fed to the dry wash

tower to remove any traces of catalyst and HCl using ion exchange technique before feeding it to

the evaporator whereas methanol distillation column has also been removed since it can be flash

separated from glycerol because there is only trace amount of water present in the system. This

approach saves cost of equipment (distillation columns) and reduces energy in absence of water

because water has higher boiling point and specific heat which requires more energy to separate.

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Figure 3.2 Proposed PFD for biodiesel production without water washing

Both models were simulated in HYSYS for the methanol to oil molar ratios of 6:1, 9:1, 12:1,

15:1, 18:1 and 20:1. Figure 3.3 shows the PFD generated in HYSYS for water (wet) washing

option. Triolein was declared as the hypothetical component since it is not included in the

HYSYS component database. Simple spreadsheet function was used for reaction and decanter

separation steps. Required data were assumed from design basis (Section 3.1). Material and

energy balance data obtained from HYSYS were used for equipment sizing and energy

consumption estimation which, in turn, was used to find the operating and fixed cost of the plant.

This is discussed in following sections in detail.

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22

Figure 3.3 HYSYS simulation of biodiesel production

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4.0 Energy Consumption

Energy required for both scenarios were derived from HYSYS simulation and after the

preliminary heat integration, total energy consumption was estimated as shown in Tables 4.1

through 4.4.

Table 4.1 Nett heating required after integration (washing option- 6:1 molar ratio)Heating

required (oC)Heat required

MJ/h Heat Provided by (refer Table 4.2)Balance heat required

(MJ/h)HE-102 25 to 60 135.874 Glycerol cooler- 37.363 MJ/h 98.510HE-103 25 to 60 285.800 FAME cooler- 285.800 MJ/h 0

Heater-1 60 to 100 458.893 458.893Q-100 60 to 100 1921.585 1921.585

Reboiler 932.818 932.818Total 3734.970 3390.897

Table 4.2 Nett cooling required after integration (washing option- 6:1 molar ratio)

HeatsourceCooling

required (oC)Energy to be

removed (MJ/h)Cooling provided to

(refer Table 4.1)Balance cooling required (MJ/h)

FAME cooler 100 to 25 702.415 HE-103 285.800 MJ/h 416.651Glycerol cooler 100 to 25 89.238 HE-102 37.363 MJ/h 51.875

MeOH recycle 65 to 60 8.625 8.625Water recycle 65 to 60 12.285 12.285

Total 812.563 489.437

While the heat integration reduces both heating and cooling requirements to some extent, not all

the heating requirement can be offered by the process due to temperature cross over. Therefore,

external heating in terms of low pressure steam and cooling in terms of the circulating cooling

water will have to be provided.

Table 4.3 Nett heating required after integration (no-washing option- 6:1 molar ratio)Heating

required (oC)Heat required

MJ/h Heat Provided by (refer Table 4.2)Balance heat required

(MJ/h)HE-102 25 to 60 135.874 Glycerol cooler- 37.363 MJ/h 98.510HE-103 25 to 60 285.800 FAME cooler- 285.800 MJ/h 0

Heater-1 60 to 100 393.369 393.369Q-100 60 to 100 532.569 532.569

24

Reboiler 0 0Total 1374.603 1024.440

Table 4.4 Nett cooling required after integration (washing option- 6:1 molar ratio)

HeatsourceCooling

required (oC)Energy to be

removed (MJ/h)Cooling provided to

(refer Table 4.1)Balance cooling required (MJ/h)

FAME cooler 100 to 25 702.415 HE-103 285.800 MJ/h 416.651Glycerol cooler 100 to 25 89.238 HE-102 37.363 MJ/h 51.875

MeOH recycle 65 to 60 8.625 8.625Water recycle 65 to 60 0 0

Total 800.287 477.151

It can be noted that cooling requirement for both washing and no-washing options are almost

identical except that the recycle water cooling is not require in no-washing option. Whereas,

heating requirement is less than one third for no-washing option than for washing option. This is

because distillation and reboiler are not required in no-washing option. This results in cost and

energy savings. On the other hand, no-washing option incurs additional cost which is discussed

in the following sections.

Figure 4.5 shows the comparison of energy consumed by washing option with no-washing for

different molar ratios ranging from 6:1 to 20:1.

Figure 4.5 Comparison for energy consumption between washing and no-washing options

25

Clearly, it can be seen that wet washing option consumes a lot of heat energy than no-washing

option. As stated earlier, this is due to the distillation column required to separate water from

methanol and glycerol. Whereas, for no-washing option the methanol and glycerol can be simply

separated by flashing which results in energy economy. Even at the highest molar ratio of 20:1,

no-washing option consumes heat energy almost same as washing option 6:1 molar ratio.

Therefore, it can be said that the presence of water in the system elevates energy consumption

greatly. Another alternative is to discard water rather than recycling it but this imposes the loss

of biodiesel because wash water carries some biodiesel while leaving the decanter.

4.1 Vapour re-compression

To further reduce the energy consumption in no-washing option, vapour re-compression cycle

was implemented in HYSYS as shown by Figure 4.6.

Figure 4.6 Schematics for vapour re-compression for no-washing option

Vapour re-compression is widely used technique for recovering low temperature heat

energy. Reducing pressure also reduces boiling point of the liquid requiring less heating while

the vapour stream leaving the flash tower, which needs to be cooled, preheats the methanol and

glycerol feed stream entering the flash separator.

26

In order to design the optimum operating pressure, a plot of vacuum pump power consumption

and methanol recovery was made as a function of operating pressure as shown in Figure 4.7. The

lower the operating pressure, higher the methanol recovery and so is the power consumption. In

order to keep the power consumption lower, some compromise will have to be made. Therefore,

70 kPa pressure was selected to keep power consumption of 50 kW and methanol recovery of

2557 kg/h. This results in 12% reduction of total heating requirement for no-washing option. The

additional equipment require for vapour re-compression is the liquid ring vacuum pump which

was estimated to cost $ 20,000. This additional cost of equipment can be recovered by the

amount of heating it saves within 15 weeks of operation (Appendix-I).

Figure 4.6 Methanol recovery and power consumption as a function of operating pressure

Next, the energy consumption from vapour re-compression was compared with no-

washing option for the methanol separation stage as shown in the Figure 4.7. It can be seen that

for 6:1 molar ratio, at least 75% of energy can be saved using vapour re-compression.

27

Figure 4.7 Comparison of energy consumption between vapour re-compression and no-washing cycles for methanol separation stage.

This reduction in energy consumption would positively affect the profitability of the plant

which is discussed in the following section in detail.

28

5.0 Cost Analysis

After the technical evaluation of the process, it is necessary to analyse the impact of molar

ratios and wet/dry washing on the economic feasibility of the plant in terms of profit/loss and the

amount of funds required to be invested. In order to estimate the initial investment, it is

important to analyse the fixed cost index (FCI) while rate of return and profitability requires to

estimate the cost of manufacturing against expected revenue from the selling of the proposed two

options (water washing and no-washing).

Some of the major contributors for fixed cost are land, equipment and interconnecting piping

and instrument costs while cost of manufacturing includes raw material, utilities costs, cost of

waste disposal/treatment, cost of raw material, and other costs such as- cost involved in labour,

taxes, research and development, sells and distribution, etc. the preliminary analysis would

indicate whether it is profitable to enter into the project or not. If preliminary analysis indicates

possibility of generating profit then further economic analysis in detail is necessary to include

interest factors, pay-back period, rate of return, net present worth of future income, etc.

1.1 Fixed Cost Index (FCI)

1.1.1 Water Washing

Table 5.1 shows the grass route cost of the equipment. Purchased cost (Cp) for equipment in

cast steel material and at atmospheric pressure condition was calculated using equation 5.1 where

the values for constants where K1, K2 and K3 were derived from course notes of CHG-4244

(plant design) (Thibault et al., 2008) and the capacity (A) was estimated from HYSYS simulation

e.g. (A) in the equation 5.1 represents heat transfer area for heat exchangers (in m2) and power

(in kW) for pumps and turbines, etc.

29

5.1

CBM, from Table 5.1, represents bare module cost (equation 5.2) that includes direct and

indirect costs for each equipment such as- material of construction of equipment, operating

pressure, etc.; CTM represents the total module cost of the equipment (equation 5.3) such as-

freight, duties & taxes, etc.; while CGR is the grass route cost (equipment 5.4) accounting for

equipment erection, interconnecting piping and instruments, etc.

5.2

Where constant FBM is chose from plant design notes.

4.3

5.4

Costs of centrifuges, vacuum pumps and ion exchange tower (no-washing only) have been

estimated online (Web-1,4). Total fixed cost for the plant was estimated to be $ 10.15 m.

Rotating equipment such as- pumps and fans will have to be bought in pairs assuming one each

will be kept as a back-up therefore, FCI includes double the cost of such machinery.

Table 5.1 Fixed cost of the plant excluding land (6:1 molar ratio, wet washing)

Equipment: Quantity CP ($) CBM0($) CTM($) CGR($)

CSTR s 3 102280.0447 184104 217243 309295

Centrifuges 3 53100 175230 206771 294386

Triolein heater 1 2463 15625 18438 26251

Wash tank 1 86511.13125 155720 183750 261610

MeOH Pre-heater 1 2393 15179 17912 25501

Oil-Heater 1 3033 19241 22705 32325

Flash Dryer 1 71797.197 237984 280821 399812

MeOH Flash Tank 1 116344.2826 383936 453045 645013

Glycerol separator 1 72334 564207 665764 947868

30

Equipment: Quantity CP ($) CBM0($) CTM($) CGR($)

MeOH Flash Heater 1 3086 19580 23104 32894

Equipment: Quantity CP ($) CBM0 CTM CGR

MeOH Distillation column 1 128377 963094 1136451 1617998

Condensor 1 3643 15937 18806 26774

Reboiler 1 3146 13761 16239 23119

Glycerol cooler 1 2480 15735 18567 26435

Triolein Feed pumps 2 6257 33788 39870 56764

MeOH Feed Pumps 2 4511 20301 23956 34107

MeOH storage tank 1 31063 102508 120960 172214

Triolein storage tank 1 67730 528297 623391 887540

Glycerol storage tank 1 73294 571693 674598 960445

Water Wash pumps 2 5152 27822 32829 46740

FAME separator 1 90057 702444 828884 1180106

FAME-water decanter 1 89684 699533 825449 1175215

Distillation Pumps 2 3534 19085 22520 32063

Pure FAME cooler 1 3607 22884 27003 38444

FAME storage tank 1 162528 536343 632885 901056

Total 10 153 975

Cp-equipment cost, CBM0-bare module cost, CTM-total module cost, CGR-grass route cost

Similarly, equipment cost for all other ratios were estimated. Table 5.3 shows the total

cost for each ratio. It can be seen that the cost increases steadily as the molar ratio increases. This

is mainly because of the cost involved in methanol distillation column.

As it can be seen from the pie chart (Figure 5.1), major cost contributor is the storage

tanks (34%), next major contributor is other process vessels (32%) such as decanters,

evaporators, etc. decanters cost more because one hour of residence time was assumed for design

purpose which increased the size of the equipment. Next major cost involved is the cost of

distillation column (19%). This cost will rise steadily for higher molar ratios whereas storage

31

cost will not be directly proportional to increased molar ratios because the plant capacity is

constant for all molar ratios.

Figure 5.1 Equipment cost break up for 6:1 molar ratio washing option (Appendix-I)

Cost of land was assumed to be $ 2 m arbitrarily. Then total FCI including land cost was

estimated to be $ 12.15 m from 6:1 molar ratio including water washing

1.1.2 Fixed Cost Index (FCI): No-Washing (Ion exchange)

Most of the equipment cost is the same as that of the washing option such as- reactors, storage

tanks and pumps because the production capacity is constant for both scenarios. The major

reduction in cost is due to the absence of distillation column and connecting equipment. Whereas

the additional cost of ion exchange tower was added. Table 5.2 shows the equipment cost break

up for 6:1 molar ratio for dry washing option.

Table 5.2 Fixed cost of the plant excluding land (6:1 molar ratio, dry washing)

Equipment: Quantity CP ($) CBM0($) CTM($) CGR($)

CSTR s 3 102280 184104 217243 309295

Centrifuges 3 53100 175230 206771 294386

Triolein heater 1 2463 15625 18438 26251

MeOH Pre-heater 1 2393 15179 17912 25501

Oil-Heater 1 3033 19241 22705 32325

Flash Dryer 1 71797 237984 280821 399812

32

Equipment: Quantity CP ($) CBM0($) CTM($) CGR($)

MeOH Flash Tank 1 116344 383936 453045 645013

Glycerol separator 1 72334 564207 665764 947868MeOH Flash Heater 1 3086 19580 23104 32894

Equipment: Quantity CP ($) CBM0 CTM CGR

Glycerol cooler 1 2480 15735 18567 26435

Triolein Feed pumps 2 6257 33788 39870 56764

MeOH Feed Pumps 2 4511 20301 23956 34107

MeOH storage tank 1 31063 102508 120960 172214

Triolein storage tank 1 67730 528297 623391 887540

Glycerol storage tank 1 73294 571693 674598 960445

FAME separator 1 90057 702444 828884 1180106

Pure FAME cooler 1 3607 22884 27003 38444

FAME storage tank 1 162528 536343 632885 901056

Ion exchange towers 2 383168

Total 7 518 120

Two ion exchange towers were considered keeping one stand by to be used during the

regeneration of first tower. The cost for resin was estimated online (Web-2) and the tower cost

was assumed using equation 5.1. The total cost of equipment for dry washing option has been

found to be $ 7.52 m. Table 5.3 compares the grass route cost of equipment for washing and no-

washing options. Worth noting that the equipment cost of highest molar ratio for no-washing

option is less than that of 6:1 ratio for water washing option. Therefore, even is the methanol to

oil molar ratio is increased to more than three folds, the cost of equipment will still be at least

20% less.

Table 5.3 Grass route cost of equipment for different molar ratios

Molar ratio Washing ($ m) No-washing ($ m)

6:1 10.15 7.52

33

9:1 10.71 7.6612:1 11.24 7.8015:1 11.75 7.9318:1 12.25 8.0620:1 12.58 8.14

5.2 Cost of Manufacturing (COM)

Cost of manufacturing plays important role in assessing profitability of the plant. While

COM higher then revenue generated is definitely not recommended, further reducing COM is

advantageous even when it is lesser than the revenue generated. Manufacturing costs can be

further divided into three categories: direct manufacturing costs, fixed manufacturing costs, and

general manufacturing expenses.

5.2.1 Direct Manufacturing Cost (DMC)

DMC mainly includes costs of;

Raw materials

Utilities

Waste treatment

Operating labor

Other costs involved in maintenance, lab charges, operating supplies and patents.

Each section is explained in detail as follows.

Raw Material Cost

The raw materials require in the plant are canola oil, methanol, catalyst NaOH and HCl which

were estimated to be $ 14.48 m per year (Web-3). Table 5.4 shows the detail break up of raw

material cost.

34

Table 5.4 Break up for yearly raw material costRaw material Hourly consumption

rate (kgéh)Unit cost ($) Total yearly cost ($)

Canola oil 4260 0.90/L 34 014 489MeOH 462 0.192/kg 770 447NaOH 42.13 0.19/kg 64 178HCl 38.14 0.215/kg 64 744Total raw material cost 34 913 860Therefore total raw material cost, including transportation cost, for the plant was

estimated to be $ 34.91 m per year. The raw material cost remains unchanged for all molar ratios

and for both the options (washing and no-washing). Although, methanol consumption, in terms

of the system loss, will slightly increase for higher molar ratios but the same can be neglected

when compared with the cost of canola oil.

Utilities

Major utilities include power, low pressure steam and cooling water for the plant. However,

required heating loads will be partly provided by the process heat, low pressure steam will be

required and so is the cooling water to provide adequate cooling. Table 5.5 shows the cost of

utilities required for biodiesel processing for washing and no-washing options at 6:1 molar ratio.

However, the cost of cooling water will be less during winter as more amount of heat/kg of water

can be removed due to low temperature as a result of natural cooling of the water.

Table 5.5 Utilities cost break up for 6:1 molar ratio

Utility Washing No-Washing

MJ/h Yearly cost ($)* MJ/h Yearly cost ($)*

Cooling water 489.436 2300 477.151 1353

LP steam 3390.897 343122 1024.440 142976

Power 241.200 114271 241.200 114271

Total 459693 258600

*Cost were estimated using CHG-4244 course notes (Thibault et al., 2008)

35

Wastewater Treatment

Major waste stream leaving the plant containing FFAs and some water vapours.

However, as discussed earlier, some literatures mention FFA as adviceable compound in

biodiesel for combustion, it can be treated to convert into biodiesel. But for the purpose of this

report, it was assumed that the FFAs be discarded. Therefore, the lump sum cost of $ 500,000

was assumed for waste disposal. It was further assumed that the cost of waste treatment does not

change on varying molar ratio or for no-washing option.

Manpower Requirements

Following steps were used to estimate the number of operators required and the cost of

labour for the manufacturing cost (Thibault et al., 2005):

1 operator = 8h/shift * 5 shifts/week * (52-2) weeks of work/year

= 2000h/yr

= 250shifts/yr

52 - 2 weeks of maintenance per year = 50 weeks of work/year

1 position = 1 shift/8h * 24 h/day * 365 days/yr

= 1095 operating shifts/yr

1095 shift/yr / 250 shifts/operating year

= 4.38 operators ~ 4.5 operators

Cost of Labour =NOL*4.5 operators/position*40 h/operator week*52 weeks/year*Wh$/h

= 9360 NOL Wh ($/yr)

Wh = $25/h = $52 000/year

NOL = (6.29 + 31.7*P2 + 0.23Nnp)1/2 7.5

36

P = 2 for liquid and gas handling.

Nnp = 10 for our process

NOL = 11.6 ~ 12

Total operators = NOL * 4.5 = 54

COL = 54 * 52000 = $ 2,808,000

Therefore total labour cost for the plant was estimated to be $ 2,808,000 per year. The

labour cost remains constant for all ratios and for no-washing option.

Other Costs

Table 5.6 shows the break-up of each cost.

Table 5.6 Other Costs (6:1 ratio washing option)

Cost Type Equation (Thibault et al, 2008) $/year

Direct Supervisory 0.18COL 505 450

Maintenance 0.06FCI 609 239

Operating Supplies 0.009FCI 91 386

Lab Charges 0.15COL 421 200

Patents 0.03COM 1 588 230

Total 3 215 495Therefore, direct manufacturing cost (DMC) was obtained by summing up the costs of raw

material, utilities, waste treatment, operating labour and other costs to get $ 41 346 632.

5.2.2 Fixed Manufacturing Cost (FMC)

FMC includes costs of depreciation, local taxes and plant overheads as shown in the Table 5.7.

Major part of FMC is contributed by depreciation cost of equipment assuming straight line

method. However, considering double declining method, cost of depreciation will be reducing

37

every year because double declining method assumes that major depreciation occurs during early

years of operation. In that case, FMC will be changing every year based on depreciation

therefore, best thing is to exclude depreciation from fixed manufacturing cost for the purpose of

generating cash flows here yearly depreciation can be added separately.

Table 5.7 Fixed manufacturing cost (FMC) (6:1 ratio washing option)

Cost Type Equation (Thibault et al, 2008) $/year

Depreciation 0.1 FCI 1 015 387

Local Taxes 0.032 FCI 324 927

Plant Overheads 0.708 COL + 0.036 FCI 2 353 607

Total 2 678 534

5.2.3 – General Manufacturing Expenses (GE)

GE involves costs of administration, distribution and selling, and research and developments as

shown in the Table 5.8 below.

Table 5.8 General manufacturing expenses (6:1 ratio washing option)

Cost Type Applicable relation $/year

Administration 0.177 COL + 0.009 FCI 588 402

Distribution 0.11 COM 5 823 512

R&D 0.05 COM 2 647 051

Total 9 493 555

38

Therefore the cost of manufacturing excluding depreciation (COMd) was obtained by summing

up the DMC, FMCd and GE to get $ 52.94 m. Figure 5.2 shows the percentage contribution on

each of these costs to the COMd. 70% of the COMd is contributed by raw material cost.

Therefore, utilizing raw material to get optimum return per kilogram of residue is important. On

the contrary, utilities account for less than 1% of total cost of manufacturing.

Figure 5.2 Cost of manufacturing Distribution (6:1 ratio washing option)

5.3 Revenue generated

Total revenue generated comes from selling of char and power. It was assumed that there

is an increasing demand for charcoal because major application for charcoal is water filtration

which will keep increasing since water is used for human consumption.

5.6

Where M is the mass flow rate in kg/h and P is the prize of the compound in $/kg.

Equation 5.6 was used to calculate yearly revenue generated by the plant where sell price of

biodiesel was assumed to be $ 4.95/gallon (Web-3) and that of glycerol was assumed to be $

0.96/kg to get gross revenue of $ 56.49 m. The revenue minus the expenses results in net profit

39

of $ 3.41 m. Similarly, Figure 5.3 shows the amount of profit generated at different molar ratios

and for no-washing option.

Figure 5.3 Net profit at different molar ratios

Amount of profit is inversely proportional to the expenses. As the molar ratio increases,

the expenses increases and profit decreases. In case of water washing option, cost of separating

water from methanol and glycerol is a major factor reducing the profit from $ 3.4 to 1 m. On the

other hand, no washing option uses ion exchange resin which does not change upon increasing

molar ratios and therefore, the expenses does not increase very much as is the case for water

washing option. Although, utilities contribute less than 1% of the total cost of manufacturing, it

plays a decisive role profitability criteria because every dollar saved on any energy consumption

is directly result in profit. Moreover, savings on equipment cost as a result of process

modification is also an important factor which increases the profit margin.

40

6.0 Conclusion and Recommendations

6.1 Conclusion

This report dealt with studying the effect of varying methanol to canola oil molar ratio for

water wash and dry wash (ion exchange) options on energy consumption and profitability of the

biodiesel plant. The two models were considered; one with widely used cycle implementing

water washing of biodiesel and second, implementing dry washing i.e. biodiesel purification

using ion exchange rather than water washing. Both the models were simulated in HYSYS for 10

million gallons of biodiesel production capacity per year using canola oil and methanol. For each

of the two models, methanol to oil molar ratio was varied from 6:1 to 20:1 in six stages.

Energy consumption was estimated from HYSYS energy balance and two scenarios were

compared to study the effect. It was found that the energy consumption, when no water present

in the system, is much less (1024 MJ/h) than the one using water washing cycle (3309 MJ/h).

Therefore, biodiesel plant be operated without water washing mainly because methanol

separation from water being difficult task requiring distillation column involving energy

intensive step. Energy consumption can be further reduced by implementing vapour re-

compression cycle for separating methanol and glycerol. Vapour re-compression recovers low

temperature heat which, otherwise, would be wasted in cold sink incurring additional cost of

cooling. 12% of overall energy consumption can be saved using vapour re-compression cycle.

In order to compare the profitability of both scenarios (washing and no-washing), fixed

cost of the plant for each molar ratio was calculated along with other applicable costs and

subtracted from revenue to find the net profit. Cost of equipment were found to be $10.15 m for

the process using water washing compared to $ 7.52 m from dry washing option. No washing

41

option requires less number of equipment and due to the absence of water, methanol can be

easily flash separated from glycerol. The net profit generated by the water wash plant was found

to be $ 3.4 m compared to $ 4.3 m for dry wash process.

Therefore, in order to conclude, it can be said that biodiesel manufacturing process would

be more beneficial if water washing step can be replaced by dry washing (ion exchange).

6.2 Recommendations

Although, proposed project appears to be a profitable and technically sound, there are

certain challenging factors involve which needs to be discussed.

6.2.1 Vegetable oils- part of the food chain

Biodiesel is made using vegetable oils and most vegetable oils are a part of human food

chain. This is a serious issue of creating global food crisis because if oils are directed to biodiesel

production, the price hike would be more likely which may create difficult for general public to

buy oils for consumption.

Therefore, using alternative to vegetable oils could be a good option e.g. used frying oils

from fast food industries. Another option could be to grow more oil seeds dedicated for biodiesel

production leaving the food chain intact.

6.2.2 Expensive raw material

As discussed earlier, vegetable oil constitutes more than 70% of the total operating cost. Profit

margin is directly affected by the raw material cost. Therefore, alternatives to expensive raw

material can be explored. Used frying oil can be very cheaper in price but this requires additional

processing and energy consumption increasing expenses as well as the biodiesel yield is much

less (~90%) which reduces the profit.

42

6.2.3 Cold flow properties

One of the major limitations of biodiesel is its cold flow property. Cold flow properties

are a major concern when the temperature of operation goes below 10 °C. Problems with

biodiesel often develop from plugged fuel lines and filters, and these problems are caused by the

formation of crystals (Yori et al., 2006). Methyl and ethyl esters of fatty acids have considerably

higher crystallization temperatures than diesel fuel. Crystal growth inhibitors for diesel fuel, also

known as pour point depressants (PPD), are available commercially (Huang et al., 2000).

Though they have been reported to reduce the pour point of biodiesel, these additives usually do

not reduce the cloud point (CP) nor improve the filterability of biodiesel at low temperatures. CP

and cold flow plug point (CFPP) temperatures for biodiesel are higher than that of petroleum

diesel. As it can be seen from the Table 6.1 that CP and CFPP of biodiesel is almost 15-20oC

higher than petroleum diesel.

Table 6.1 Comparison of cloud point (CP) and cold flow plug point (CFPP) and pour point (PP) temperatures for pure biodiesel and petroleum diesel (Yori et al., 2006).

CP (oC) CFPP (oC) PP (oC)Pure biodiesel -3 -10 to -14 -9 to -16

Petroleum diesel -17 -31 -24

Since the cloud point is highly related to the fatty acid composition of biodiesel (Imahara et

al., 2006), (Knothe et al., 2005), higher amount of saturated free fatty acids (FFAs) of long and

linear chains are responsible for higher cloud points. Therefore, removing or reacting excess

fatty acid might cause the CP to lower. Also, unconverted mono and di glycerides increases the

crystallization temperature of biodiesel. Upon acid esterification the FFA can be converted to

methyl ester to bring down the CP and glycerides can be converted to glycerol which can be

separated from biodiesel (Sheehan et al., 1998).

43

For additional details on cold flow properties, refer Appendix-I.

Improvements, to some extent, can also be made through chemical combinations into stable solid

compounds, or by winterization process (using solvent) or dry fractionation (without solvent).

Each additional step is energy and cost consuming which would result in the loss of profit

margin.

6.2.4 Less incentive (profit margin)

Currently fossil energy is most widely used because it is a cheaper alternative than

renewable energy. The higher cost of biodiesel (limited profit margin) makes it less popular then

fossil diesel business venture. Therefore, government should intervene and offer certain benefits

to biodiesel producers and consumers such as- CO2 tax credits, tax rebate, cheaper (duty/tax free)

raw material, offer to buy biodiesel at a set price, make people aware of the importance of

renewable energy with respect to CO2 emission. Also, when finite amount of fossil fuels will

extinct, energy consumption by human will have to come from renewable sources. Therefore, it

is very important that biodiesel (renewable fuels) be made popular and attractive choice.

44

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Myint L, 2009. Process analysis and optimization of biodiesel production from soybean oil. Clean Techn Environ Policy 11, 263–276.

Sheehan, J., Dunahay, T., Benemann, J., Roessler, P. 1998. A Look Back at the U.S. Departmentof Energy’s Aquatic Species Program-Biodiesel from Algae. National Renewable EnergyLaboratory (NREL) Report: NREmP-580-24190. Golden, CO.

Srivastava PK, Verma M. Methyl ester of karanja oil as an alternativerenewable source energy. Fuel 2008;87:1673–7.

Tomasevic, A.V., Marinkovic, S.S.S., 2003. Methanolysis of usedfrying oil. Fuel Process. Technol. 81, 1–6.

Yori J.C., Miguel. Depression of the Cloud Point of Biodiesel by Reaction over SolidAcids Energy & Fuels 2006, 20, 2721-2726

46

Zhang Y, Dub MA, McLean DD, Kates M. Biodiesel production from waste cooking oil: 2. Economic assessment and sensitivity analysis. Bioresour Technol 2003;90:229–40.

“Survey of Diesel Fuels and Aviation Kerosene’s From U.S. Military Installations”, Paper by Steven R Westbrook (SwRI) and Maurice E. LePera (US Army TARDEC), Presented at the 6th International Conference on Stability and Handling of Liquid Fuels, October 13-17, 1997, Vancouver, B.C., Canada.

7.1 Web references

Web-1 http://www.matche.com/EquipCost/Centrifuge.htm

Web-2 http://www.arborbiofuelscompany.com/Biodiesel_Dry_Washing_Questions_and_Answers.html

Web-3 www.icis.com

Web-4 http://www.gnsolidscontrol.com/decanting-centrifuge/

Web-5 http://www.nrel.gov/docs/fy04osti/36240.pdf)

Web-6 http://ezinearticles.com/?Cold-Soak-Filtration-Test-Mandated-For-Biodiesel-Testing&id=1735307

Web-7 http://www.biodieselexpertsintl.com/Default.aspx?tabid=414

Web-8 http://www.uiweb.uidaho.edu/bioenergy/Bioshortcourse/Diesel_Fuel_Props.htm

47

Appendix-I

I.1 Additional information on Cold Flow Properties (literature review)

As discussed briefly in the report (Section 9.2.3), one of the main reasons for using

biodiesel in blend with petroleum diesel is its high crystallization temperature. Three important

cold weather parameters that define operability for bio and petroleum diesel are cloud point

(CP), pour point (PP) and cold flow plugging point (CFPP) temperatures. Each one of them is

discussed briefly. Over the years, so many efforts has been made to understand how to deal with

the cold flow properties of diesel fuel—or the low temperature operability—of existing diesel

fuel. The cloud point and the cold filter plugging point (CFPP) or the low temperature

filterability test (LTFT) commonly characterize the low temperature operability of diesel fuel.

I.1.1 Cloud Point

A fuel property that is particularly important for the low temperature operability of diesel

fuel is the cloud point. The cloud point is the temperature at which a cloud of wax crystals first

appears in a liquid upon cooling. Therefore, it is an index of the lowest temperature of the fuel’s

utility under certain applications. Operating at temperatures below the cloud point for a diesel

fuel can result in fuel filter clogging due to the wax crystals. As described in ASTM D2500, the

cloud point is determined by visually inspecting for a haze in the normally clear fuel, while the

fuel is cooled under carefully controlled conditions. The apparatus used for this test is shown in

Figure 2.1. The cloud point is an important property for biodiesel since biodiesel fuels typically

have higher cloud points, i.e., crystals begin to form at higher temperature, than standard diesel

fuel.

This feature has implications on the use of biodiesel in cold weather applications.

An alternative procedure for measuring the cloud point of diesel/biodiesel fuels is ASTM

48

D5773. A summary of the procedure steps is 1) the sample is cooled in a Peltier device at a

constant rate, 2) the sample is continuously monitored by optical detectors, and 3) the

temperature is recorded that corresponds to the first formation of a cloud in the fuel. The

repeatability of the cloud point test is <0.5°C and the reproducibility is <2.6°C.

Figure 2.1 Scehmatic diagram of the apparatus used for cloud point measurement (Web-5)

I.1.2 Pour Point

A second measure of the low temperature performance of diesel/biodiesel fuels is the pour

point. The pour point is the lowest temperature at which a fuel sample will flow. Therefore, the

pour point provides an index of the lowest temperature of the fuel’s utility for certain

applications. The pour point also has implications for the handling of fuels during cold

temperatures. The standard procedure for measuring the pour point of fuels is ASTM D97. A

summary of the procedure steps is 1) the sample is cooled at a specified rate, 2) the sample is

examined at 3°C intervals for flow, and 3) the lowest temperature at which sample movement is

49

observed is noted. The repeatability of the pour point test is <3°C and the reproducibility is

<6°C.

I.1.3 Cold Flow Plug Point (CFPP)

The temperature at which a fuel will cause a fuel filter to plug due to fuel components, which

have begun to crystallize or gel. When diesel fuels start to solidify, they initially form microscopic

crystals. If allowed to agglomerate, these crystals will grow large enough where they can plug fuel filters

and fuel lines.  Anti-gelling additives can be used to disrupt the agglomeration process. The CFPP is less

conservative than the cloud point, and is considered by some to be the true indication of low

temperature operability.

The shows CFPP results for biodiesel and Number 2 diesel fuel at various concentrations. The

University of Missouri prepared the fuel blends and they were analyzed at Cleveland Technical

Center in Kansas City. The data suggests that the fuel mixture starts to gel sooner as the

concentration of biodiesel increases. High concentrations of biodiesel (i.e. blends over 20%) may

not be appropriate for use in cold climates without blending extreme percentages of kerosene

combined with proven cold flow improvers specific to conventional diesel fuel.

Figure I.1 CFPP for biodiesel blends (Survey of Diesel Fuels)

50

I.1.4 Analysis

I.1.4.1 Cold Soak Filtration

The newest testing requirement for biodiesel fuel testing is the cold soak filtration test.

The procedure was added to the ASTM Method in October 2008. Figure I.2 shows the picture of

typical cold soak filters developed by Biodiesel Experts International in association with

Schroeder Biofuels. A new proprietary multi-stage separation technology designed specifically

to ensure that biodiesel products conform to ASTM 6517 standard for cold flow properties. The

Cold Clear TM system consists of a three-stage bank of housings using a combination of

filtration and adsorption principles to capture compounds that could cause plugging or

crystallization in biodiesel fluids. It is designed to improve purity standards in alternative fuels

for consumers (Web-6).

In the past, substandard biodiesel has been known to precipitate material out of solution

when exposed to cold temperatures. If a solid material were to precipitate out of the biofuel when

it is used in an engine, it can lead to extensive damage. Therefore, legislators took action to

prevent such substandard product from making it to the market.

In scientific terms, cold soak filtration measures time in seconds it takes for cold soaked

biodiesel to pass through two 0.8 micron filters. It also measures the amount of particulate matter

collected on the filter. This works to ensure that end users will not have clogged filters or worse

problems with their engines when using biodiesel in cold temperatures. It also ensures that

producers will maintain a high level of brand integrity as guaranteed by their customer’s

satisfaction with their product.

51

Figure I.2 Picture of typical cold soak filters (Web-7)

The schematic diagram of lab scale CFPP test method is shown in the Figure I.3. It

determines the lowest temperature where 20 ml of fuel can be drawn through a 45 micron screen

in 60 seconds with 200 mm of water (1.96 kPa) of vacuum. 

Figure I.3 Schematic diagram of lab scale CFPP test method (Web-8).

I.2 Material Balance (from HYSYS)

52

The following data represents 6:1 no-washing option. Refer “hysys-data” file for data pertaining

to all other ratios. The following Tables should be refer with Figure 3.3 for stream identifications.

Name 1.00 2.00 3.00 4.00 5.00 6.00Vapour Fraction 0.00 0.60 0.00 1.00 0.00 0.00Temperature [C] 65.00 120.00 25.28 120.00 120.00 65.53Pressure [kPa] 500.00 101.30 500.00 101.30 101.30 250.00Molar Flow [kgmole/h] 29.56 15.98 4.81 9.63 6.35 14.47Mass Flow [kg/h] 5042.46 1017.64 4259.95 305.82 711.82 4246.17Std Ideal Liq Vol Flow [m3/h] 5.64 1.05 4.79 0.38 0.67 4.84Heat Flow [kJ/h] -15762951.50 -5722629.82 -9066841.60 -1908430.09 -3814199.74 -10128432.46Molar Enthalpy [kJ/kgmole] -533245.49 -358046.25 -1884606.44 -198182.57 -600351.42 -699941.11(M-Oleate) [kg/h] 4236.59 211.83 0.00 0.33 211.50 4236.59 (Methanol) [kg/h] 330.62 330.62 0.00 300.27 30.35 3.31(Glycerol) [kg/h] 428.00 428.00 0.00 0.73 427.27 0.86 (triolein*) [kg/h] 42.60 42.60 4259.95 0.00 42.60 4.26 (H2O) [kg/h] 4.64 4.59 0.00 4.50 0.09 1.16Heat CapacitykJ/kg-C 2.23 2.32 1.61 1.61 2.63 2.07Heat Capacity [kJ/kgmole-C] 380.20 147.99 1425.95 51.00 295.01 608.43

Name FAME-2 FAME-21 FAME-2-2 fameL glyce Glycerol OutVapour Fraction 0.00 1.00 0.00 0.00 0.00 0.00Temperature [C] 65.00 120.00 25.00 120.00 120.00 65.00Pressure [kPa] 101.30 101.30 101.30 101.30 101.30 500.00Molar Flow [kgmole/h] 14.29 0.00 0.71 0.79 5.56 4.65Mass Flow [kg/h] 4236.59 0.00 211.83 247.85 463.97 428.00Std Ideal Liq Vol Flow [m3/h] 4.83 0.00 0.24 0.28 0.38 0.34Heat Flow [kJ/h] -10075694.81 0.00 -520672.65 -556595.77 -3257603.96 -3104795.42Molar Enthalpy [kJ/kgmole] -705152.74 -198182.57 -728790.92 -703705.54 -585654.72 -668067.75(M-Oleate) [kg/h] 4236.59 0.00 211.83 210.96 0.54 0.00 (Methanol) [kg/h] 0.00 0.00 0.00 1.13 29.23 0.00(Glycerol) [kg/h] 0.00 0.00 0.00 0.39 426.89 428.00 (triolein*) [kg/h] 0.00 0.00 0.00 35.38 7.22 0.00 (H2O) [kg/h] 0.00 0.00 0.00 0.00 0.09 0.00Heat Capacity [kJ/kg-C] 2.07 1.61 1.92 2.24 2.84 2.65Heat Capacity [kJ/kgmole-C] 613.68 51.00 567.85 700.98 237.28 243.97

53

Name Glycerol-2-2 Glycerol-rich Glycerol-44 MeOHHeated MeOH

Heated Triolein

Vapour Fraction 0.00 0.00 0.00 0.00 0.00 0.00Temperature [C] 65.00 65.41 56.17 25.00 65.00 65.00Pressure [kPa] 101.30 101.30 101.00 101.30 500.00 500.00Molar Flow [kgmole/h] 4.64 14.47 0.01 28.95 28.95 4.81Mass Flow [kg/h] 427.15 4246.17 0.86 924.00 924.00 4259.95Std Ideal Liq Vol Flow [m3/h] 0.34 4.84 0.00 1.16 1.16 4.79Heat Flow [kJ/h] -3098585.83 -10129432.86 -6223.31 -6943145.03 -6807269.37 -8781041.58Molar Enthalpy [kJ/kgmole] -668067.75 -700010.24 -670214.36 -239836.39 -235142.85 -1825200.91(M-Oleate) [kg/h] 0.00 4236.59 0.00 0.00 0.00 0.00 (Methanol) [kg/h] 0.00 3.31 0.00 919.38 919.38 0.00(Glycerol) [kg/h] 427.15 0.86 0.86 0.00 0.00 0.00 (triolein*) [kg/h] 0.00 4.26 0.00 0.00 0.00 4259.95 (H2O) [kg/h] 0.00 1.16 0.00 4.62 4.62 0.00Heat Capacity [kJ/kg-C] 2.65 2.07 2.63 3.61 3.76 1.77Heat Capacity [kJ/kgmole-C] 243.97 608.30 242.24 115.13 119.92 1564.14

Name MeOH Out MeOH-1 MeOH-2 MeOH-2-2 MeOH-rich MeOH-rich-1Vapour Fraction 0.00 0.00 1.00 0.00 0.00 0.00Temperature [C] 65.00 25.19 65.00 25.00 42.34 42.28Pressure [kPa] 500.00 500.00 101.30 101.30 202.30 101.00Molar Flow [kgmole/h] 10.32 28.95 0.10 10.22 15.98 15.98Mass Flow [kg/h] 330.62 924.00 3.31 327.32 1017.64 1017.64Std Ideal Liq Vol Flow [m3/h] 0.42 1.16 0.00 0.41 1.05 1.05Heat Flow [kJ/h] -2421992.44 -6942520.80 -20582.43 -2445868.30 -6255190.27 -6255347.98Molar Enthalpy [kJ/kgmole] -234725.35 -239814.83 -199472.85 -239433.60 -391366.82 -391376.68(M-Oleate) [kg/h] 0.00 0.00 0.00 0.00 211.83 211.83 (Methanol) [kg/h] 330.62 919.38 3.31 327.32 330.62 330.62(Glycerol) [kg/h] 0.00 0.00 0.00 0.00 428.00 428.00 (triolein*) [kg/h] 0.00 0.00 0.00 0.00 42.60 42.60 (H2O) [kg/h] 0.00 4.62 0.00 0.00 4.59 4.59Heat CapacitykJ/kg-C 3.75 3.61 1.47 3.60 2.79 2.79Heat CapacitykJ/kgmole-C 120.31 115.15 47.00 115.48 177.35 177.34

Name to flash To-Decanter To-MeOH-rich toEvap Triolein Triolein Out

54

Vapour Fraction 0.00 0.00 0.00 0.00 0.00 0.00Temperature [C] 100.00 65.53 56.17 56.17 25.00 65.00Pressure [kPa] 101.30 250.00 101.00 101.30 200.00 500.00Molar Flow [kgmole/h] 14.29 14.47 0.18 14.29 4.81 0.05Mass Flow [kg/h] 4236.65 4246.17 9.52 4236.65 4259.95 42.60Std Ideal Liq Vol Flow [m3/h] 4.83 4.84 0.01 4.83 4.79 0.05Heat Flow [kJ/h] -9760038.51 -10128432.46 -56696.85 -10153407.8 -9068769.47 -87810.42Molar Enthalpy [kJ/kgmole] -682907.36 -699941.11 -317620.50 -710431.32 -1885007.16 -1825200.91(M-Oleate) [kg/h] 4236.59 4236.59 0.00 4236.59 0.00 0.00 (Methanol) [kg/h] 0.00 3.31 3.31 0.00 0.00 0.00(Glycerol) [kg/h] 0.00 0.86 0.86 0.00 0.00 0.00 (triolein*) [kg/h] 0.00 4.26 4.26 0.00 4259.95 42.60 (H2O) [kg/h] 0.06 1.16 1.10 0.06 0.00 0.00Heat CapacitykJ/kg-C 2.20 2.07 2.79 2.04 1.61 1.77Heat CapacitykJ/kgmole-C 651.90 608.43 148.80 603.64 1424.95 1564.14

Name Triolein-2-2 Water Water-2 water-22 water-44 Water-2-2Vapour Fraction 0.00 0.00 0.00 0.00 0.00 0.00Temperature [C] 65.00 65.00 65.00 56.17 56.17 65.00Pressure [kPa] 101.30 500.00 101.30 101.30 101.00 101.30Molar Flow [kgmole/h] 0.04 0.26 0.06 0.00 0.06 0.19Mass Flow [kg/h] 38.34 4.64 1.16 0.06 1.10 3.48Std Ideal Liq Vol Flow [m3/h] 0.04 0.00 0.00 0.00 0.00 0.00Heat Flow [kJ/h] -79029.37 -72658.43 -18164.99 -910.41 -17297.74 -54494.97Molar Enthalpy [kJ/kgmole] -1825200.91 -281854.72 -281860.67 -282530.30 -282530.30 -281860.67(M-Oleate) [kg/h] 0.00 0.00 0.00 0.00 0.00 0.00 (Methanol) [kg/h] 0.00 0.00 0.00 0.00 0.00 0.00(Glycerol) [kg/h] 0.00 0.00 0.00 0.00 0.00 0.00 (triolein*) [kg/h] 38.34 0.00 0.00 0.00 0.00 0.00 (H2O) [kg/h] 0.00 4.64 1.16 0.06 1.10 3.48Heat CapacitykJ/kg-C 1.77 4.20 4.20 4.21 4.21 4.20Heat Capacity [kJ/kgmole-C] 1564.14 75.73 75.75 75.92 75.92 75.75

Name FAME FAME Out Glycerol+Water

Glycerol-2 Mixed Meth + Recycle 1

not

Vapour Fraction 0.00 0.00 0.01 0.00 0.00 1.00Temperature [C] 56.17 65.00 90.39 65.00 25.00 65.53

55

Pressure [kPa] 101.30 500.00 101.30 101.30 500.00 250.00Molar Flow [kgmole/h]

14.29 14.29 0.27 0.01 28.95 0.00

Mass Flow [kg/h] 4236.59 4236.59 5.49 0.86 924.00 0.00Std Ideal Liq Vol

Flow [m3/h]4.83 4.83 0.01 0.00 1.16 0.00

Heat Flow [kJ/h] -10152497.49 -10075694.81 -76918.11 -6209.59 -6943143.32 0.00Molar Enthalpy

[kJ/kgmole]-710527.82 -705152.74 -

289388.16-668067.75 -239836.33 -

231845.28

(M-Oleate) [kg/h] 4236.59 4236.59 0.00 0.00 0.00 0.00(Methanol) [kg/h] 0.00 0.00 0.27 0.00 919.38 0.00(Glycerol) [kg/h] 0.00 0.00 0.73 0.86 0.00 0.00(triolein*) [kg/h] 0.00 0.00 0.00 0.00 0.00 0.00

(H2O) [kg/h] 0.00 0.00 4.50 0.00 4.62 0.00Heat Capacity

[kJ/kg-C]2.04 2.07 3.95 2.65 3.61 1.79

Heat Capacity [kJ/kgmole-C]

603.76 613.68 81.65 243.97 115.13 37.05

Name Meth-44 Pure FAME Pure MeOH Triolein-2Vapour Fraction 0.00 0.00 0.00 0.00Temperature [C] 56.17 101.11 25.00 65.00Pressure [kPa] 101.00 101.30 500.00 101.30Molar Flow [kgmole/h] 0.10 15.08 28.95 0.00Mass Flow [kg/h] 3.31 4484.50 924.00 4.26Std Ideal Liq Vol Flow [m3/h] 0.00 5.11 1.16 0.00Heat Flow [kJ/h] -24328.95 -10316634.28 -6943143.32 -8781.04Molar Enthalpy [kJ/kgmole] -235781.99 -683998.03 -239836.33 -1825200.91(M-Oleate) [kg/h] 0.00 4447.55 0.00 0.00 (Methanol) [kg/h] 3.31 1.13 919.38 0.00(Glycerol) [kg/h] 0.00 0.39 0.00 0.00 (triolein*) [kg/h] 0.00 35.38 0.00 4.26 (H2O) [kg/h] 0.00 0.06 4.62 0.00Heat Capacity [kJ/kg-C] 3.72 2.20 3.61 1.77Heat Capacity [kJ/kgmole-C] 119.04 654.48 115.13 1564.14

Name waterDrop WaterForWashing watervap-2 Triolein-44

56

Vapour Fraction 0.00 0.00 1.00 0.00Temperature [C] 64.48 25.00 101.11 56.17Pressure [kPa] 101.30 250.00 101.30 101.00Molar Flow [kgmole/h] 9.36 0.00 0.00 0.00Mass Flow [kg/h] 300.00 0.00 0.00 4.26Std Ideal Liq Vol Flow [m3/h] 0.38 0.00 0.00 0.00Heat Flow [kJ/h] -2198264.69 0.00 0.00 -8846.85Molar Enthalpy [kJ/kgmole] -234788.27 -284900.44 -213033.84 -1838879.64(M-Oleate) [kg/h] 0.00 0.00 0.00 0.00 (Methanol) [kg/h] 300.00 0.00 0.00 0.00(Glycerol) [kg/h] 0.00 0.00 0.00 0.00 (triolein*) [kg/h] 0.00 0.00 0.00 4.26 (H2O) [kg/h] 0.00 0.00 0.00 0.00Heat Capacity [kJ/kg-C] 3.75 4.20 1.65 1.73Heat Capacity [kJ/kgmole-C] 120.23 75.69 44.68 1534.04

I.3 Energy Balance (from HYSYS)

Name HE-101 P-102 P-101 HE-103 HE-102 p-1 cond-1 reb-1Heat Flow [kJ/h] -622.52 624.23 1927.87 285800.02 135873.94 1000.4 2478145.9 2110244.56Name p2 heater-1 Q-100 Heat Flow [kJ/h] 157.70 393369.39 532560.45

I.4 Equipment Sizing

Water washing optionCapacity 6:1 9:1 12:1 15:1 18:1 20:01

Reactor m3 2.475 2.716071 2.957143 3.198214 3.439286 3.6

57

L M 2.32414344 2.396535 2.464739 2.529313 2.590703 2.630044D M 1.16207172 1.198267 1.23237 1.264657 1.295352 1.315022centrifuge M3/h 5.95 6.53 7.10 7.68 8.26 8.64Triolein heater m2 0.45365079 0.453651 0.453651 0.453651 0.453651 0.453651Wash tank m3 6.825 6.825 6.825 6.825 6.825 6.85875MeOH Preheater m2 0.21567302 0.323065 0.430457 0.537849 0.64524 0.716835FAME Heater m2 1.93136785 1.931368 1.931368 1.931368 1.931368 1.932748Flash Dryer m3 9.72 9.72 9.72 9.72 9.72 9.72MeOH FlashTank m3 3.28 4.27 5.26 6.25 7.24 7.9Glycerol Flash Tank m3 1.3 1.313714 1.327429 1.341143 1.354857 1.364MeOH flash heater m2 2.09322985 2.651559 3.209888 3.768217 4.326546 4.698766Distillation column-1 4 5.945714 7.891429 9.837143 11.78286 13.08Condensor-1 W 4.04100926 7.144033 10.24706 13.35008 16.4531 18.52179Reboiler-1 W 2.27794383 8.960196 15.64245 22.3247 29.00695 33.46179Glycerol cooler W 0.49576667 0.495767 0.495767 0.495767 0.495767 0.495767Pump-1 W 535.518611 535.5186 535.5186 535.5186 535.5186 535.5186Pump-2 W 173.396389 259.7373 346.0782 432.4191 518.76 576.3206Tank-1 m3 1.98E+00 2.96592 3.951841 4.937761 5.923682 6.580962Tank-2 m3 138.123607 138.1236 138.1236 138.1236 138.1236 138.1236Tank-3 m3 10.0304048 10.0304 10.0304 10.0304 10.0304 10.0304Pump-3 W 277.777778 277.7778 277.7778 277.7778 277.7778 277.7778Decanter-1 m3 9.4 10.225 11.05 11.875 12.7 13.25Decanter-2 m3 9.1 9.1 9.1 9.1 9.1 9.15Pump-3 W 68.8338889 87.33675 105.8396 124.3425 142.8453 155.1806FAME cooler m2 3.90230875 3.902309 3.902309 3.902309 3.902309 3.902309

No-washing option Capacity 6:1 9:1 12:1 15:1 18:1 20:1

Reactor m3 2.475 2.716071 2.957143 3.198214 3.439286 3.6L M 2.32414344 2.396535 2.464739 2.529313 2.590703 2.630044D M 1.16207172 1.198267 1.23237 1.264657 1.295352 1.315022centrifuge M3/h 5.95 6.53 7.10 7.68 8.26 8.64Triolein heater W 0.45365079 0.453651 0.453651 0.453651 0.453651 0.453651MeOH Preheater W 0.21540149 0.337841 0.46028 0.58272 0.705159 0.786785FAME Heater W 1.93136785 1.931368 1.931368 1.931368 1.931368 1.931368Flash Dryer 9.72 9.72 9.72 9.72 9.72 9.72MeOH FlashTank W 2.42916667 3.368062 4.306957 5.245853 6.184748 6.810678Glycerol Flash Tank m3 1.5875 1.536395 1.485291 1.434186 1.383081 1.349011MeOH flash heater W 0.5307342 1.117335 1.703936 2.290537 2.877138 3.268205Glycerol cooler M2 0.49576667 0.495767 0.495767 0.495767 0.495767 0.495767Pump-1 W 535.518611 535.5186 535.5186 535.5186 535.5186 535.5186Pump-2 W 173.396389 259.7373 346.0782 432.4191 518.76 576.3206

58

Tank-1 W 1.98 2.96592 3.951841 4.937761 5.923682 6.580962Tank-2 W 138.123607 138.1236 138.1236 138.1236 138.1236 138.1236Tank-3 m3 10.0304048 10.0304 10.0304 10.0304 10.0304 10.0304Decanter-1 m3 9.67430556 10.45672 11.23913 12.02154 12.80396 13.32557Pump-3 W 68.8338889 82.58377 96.33365 110.0835 123.8334 133FAME cooler m2 3.90230875 3.902309 3.902309 3.902309 3.902309 3.902309

I.5 Heat IntegrationWashing 6:1

Heat required kJ/h Heatsource oC Q avail cooling

HE-10225 to 60 135874 98510.8 frGlycerol FAME

100 to 25 702415.5 296604 416651

HE-10325 to 60 285800 0 frFAME Glycerol

100 to 25 89238 37363 51875

Heater-160 to 100 458893 437983

MeOH recycle

65 to 60 8625 8625

Q-10060 to 100 1921585 1921585

Water recycle

65 to 60 12285 12285

reboiler 932818 932818

Total 3734970 3390897 812563.5

75 489436.

375

Washing 20:1 Heat required kJ/h Heatsource

FAME100 to 25Glycerol100 to 25

Q avail coolingHE-10225 to 60 451606 414242.8 frGlycerol 702415.7 296604 416651

HE-10325 to 60 285800 0 frFAME 89238 37363 51874Heater-160 to 100 458893 408819.3

MeOH recycle65 to 60l 48918.75 48918

Q-10060 to 100 4313464 4313464

Water recycle65 to 60 1155 1155

reboiler 13702602 13702602

Total 19212365 18839128 841727.3 518600

59

No washing 6:1

Heat required kJ/h Heatsource Q avail cooling

HE-10225 to 60 135874 98510.8

frGlycerol FAME100 to 25 702415 296604 416651

HE-10325 to 60 285800 0 frFAME

Glycerol100 to 25 89238 37363 51875

Heater-160 to 100 393369 393369

MeOH recycle65 to 60 8625 8625

Q-10060 to 100 532560 532560

Water recycle65 to 60 0 0

Total 1347603 1024440 800278 477151

No washing 20:1

Heat required kJ/h Heatsource Q avail cooling

HE-10225 to 60 135874 98510 frGlycerol FAME100 to 25 702415 296604 416651HE-10325 to 60 285800 0 frFAME

Glycerol100 to 25 89238 37363 51874

Heater-160 to 100 393394 344437

MeOH recycle65 to 60l 48956 48956

Q-10060 to 100 3000212 3000212

Water recycle65 to 60 0

Total 3815280 3443161

840609 517482

I.6 Cost of Equipment

WashingCapital Cost 6:1 9:1 12:1 15:1 18:1 20:1

Equipment: PFD-1CP ($)

60

Reactor 102,280 106,574 110,794 114,948 119,045 121,746centrifuge 53,100 53,100 53,100 53,100 53,100 53,100Triolein heater 2,463 2,463 2,463 2,463 2,463 2,463Wash tank 86,511 86,511 86,511 86,511 86,511 86,511MeOH Preheater 2,393 2,415 2,454 2,498 2,544 2,574Heater 3,033 3,033 3,033 3,033 3,033 3,033Flash Dryer 71,797 71,797 71,797 71,797 71,797 71,797MeOH Flash Tank 116,344 132,786 148,579 163,909 178,894 188,734Glycerol Flash Tank 72,334 72,334 72,334 72,334 72,334 72,334MeOH Flash Heater 3,086 3,260 3,421 3,572 3,715 3,806Distillation column-1 128,377 159,239 188,607 217,088 245,001 263,391Condensor-1 3,643 4,348 4,942 5,472 5,959 6,265Reboiler-1 3,146 4,706 5,835 6,799 7,668 8,210Glycerol cooler 2,480 2,480 2,480 2,480 2,480 2,480Pump-1 6,257 6,257 6,257 6,257 6,257 6,257Pump-2 4,511 5,054 5,492 5,866 6,197 6,399Tank-1 31,063 36,982 42,528 47,832 52,966 56,318Tank-2 67,730 67,730 67,730 67,730 67,730 67,730Tank-3 73,294 73,294 73,294 73,294 73,294 73,294Pump-3 5,152 5,152 5,152 5,152 5,152 5,152Decanter-1 90,057 91,040 91,967 92,844 93,677 94,211Decanter-2 89,684 89,684 89,684 89,684 89,684 89,747Pump-3 3,534 3,756 3,949 4,122 4,279 4,376FAME Cooler 3,607 3,607 3,607 3,607 3,607 3,607Tank-4 162,528 162,528 162,528 162,528 162,528 162,528

 

 

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