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OBJECTIVE

The objective of this experiment is to understand the usage of valve and distillation specificationusing HYSYS software.

THEORY

Methanol, also known as methyl alcohol, wood alcohol, woodnaphtha or wood spirits, is

achemical with theformulaCH3OH(often abbreviated MeOH). Methanol acquired the name

"wood alcohol" because it was once produced chiefly as a byproduct of thedestructive

distillation of wood. Modern methanol is produced in a catalytic industrial process directly

fromcarbon monoxide,carbon dioxide,andhydrogen.

Methanol is the simplest alcohol, and is a light,volatile,colorless,flammable liquid with a

distinctive odor very similar to, but slightly sweeter than, that ofethanol (drinking alcohol).[5]

At

room temperature, it is apolar liquid,and is used as anantifreeze,solvent,fuel,and as

adenaturant forethanol.It is also used for producingbiodiesel viatransesterification reaction.

Methanol is produced naturally in theanaerobicmetabolism of many varieties of bacteria, and is

ubiquitous in small amounts in the environment. As a result, there is a small fraction of methanol

vapor in the atmosphere. Over the course of several days, atmospheric methanol isoxidized with

the help of sunlight to carbon dioxide and water.

Methanol burns inoxygen including open air, forming carbon dioxide and water:

2 CH3OH + 3 O2 2 CO2+ 4 H2O

Methanol ingested in large quantities is metabolized toformic acid orformate salts, which is

poisonous to the central nervous system, and may cause blindness, coma, and death. Because of

these toxic properties, methanol is frequently used as a denaturant additive for ethanol

manufactured for industrial uses.

The experiment production of methanol is carried out in a moderate-pressure synthesis

loop by direct hydrogenation of carbon dioxide, which generates a liquid product that contains abinary mixture of methanol and water in approximately equal proportions. To provide

commercial methanol that is nearly free of water, dehydration is achieved commonly by

distillation. The simulation considered an equimolar mixture at 2700 kmol/hr at 25oC and 5.2

bar. It is then split and fed to two distillation columns, one at a reduced pressure, with the designspecification shown in the following table.

http://en.wikipedia.org/wiki/Naphthahttp://en.wikipedia.org/wiki/Chemical_compoundhttp://en.wikipedia.org/wiki/Chemical_formulahttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Destructive_distillationhttp://en.wikipedia.org/wiki/Destructive_distillationhttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Volatility_(chemistry)http://en.wikipedia.org/wiki/Flammablehttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Methanol#cite_note-ershdb-5http://en.wikipedia.org/wiki/Methanol#cite_note-ershdb-5http://en.wikipedia.org/wiki/Methanol#cite_note-ershdb-5http://en.wikipedia.org/wiki/Solvent#Solvent_classificationshttp://en.wikipedia.org/wiki/Antifreeze_(coolant)http://en.wikipedia.org/wiki/Solventhttp://en.wikipedia.org/wiki/Fuelhttp://en.wikipedia.org/wiki/Denaturation_(food)http://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Biodieselhttp://en.wikipedia.org/wiki/Transesterificationhttp://en.wikipedia.org/wiki/Anaerobic_organismhttp://en.wikipedia.org/wiki/Metabolismhttp://en.wikipedia.org/wiki/Oxidizedhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Formic_acidhttp://en.wikipedia.org/wiki/Formatehttp://en.wikipedia.org/wiki/Formatehttp://en.wikipedia.org/wiki/Formic_acidhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxidizedhttp://en.wikipedia.org/wiki/Metabolismhttp://en.wikipedia.org/wiki/Anaerobic_organismhttp://en.wikipedia.org/wiki/Transesterificationhttp://en.wikipedia.org/wiki/Biodieselhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Denaturation_(food)http://en.wikipedia.org/wiki/Fuelhttp://en.wikipedia.org/wiki/Solventhttp://en.wikipedia.org/wiki/Antifreeze_(coolant)http://en.wikipedia.org/wiki/Solvent#Solvent_classificationshttp://en.wikipedia.org/wiki/Methanol#cite_note-ershdb-5http://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Flammablehttp://en.wikipedia.org/wiki/Volatility_(chemistry)http://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Destructive_distillationhttp://en.wikipedia.org/wiki/Destructive_distillationhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Chemical_formulahttp://en.wikipedia.org/wiki/Chemical_compoundhttp://en.wikipedia.org/wiki/Naphtha

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Condition DC1 DC2

Pressure (bar) 5.2 1.01

Number of trays 16 13

Feed Tray* 12 9

Reflux ratio 1.26 0.834

XD (mole fraction) 0.96 0.96

XB (mole fraction) 0.04 0.04

*Count from the top of DC

Hint that use in the experiment:

1. Use SRK Equation of state fluid package2. Split ratio is used.3. Used total condenser for both of the DC

The balance equation for distillation column is:

a) Overall material balance

(d(ML,I + Mv,i)) /dt= Li+1 + Vi-1 + Vi

b) Component material balance

(d(ML,I X I,j+ Mv,IY I,j)) /dt= Li+1 Xi+1,j + Vi-1LiXi,jLiXi,jViYi,j

c) Energy balance

(d(ML,I X I,j+ Mv,IY I,j)) /dt= Li+1 HL,i+1 + Vi-1LiHi,jLiXv,i-1ViHv,i

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ML,I and Mv,Iare the holdups in the liquid and vapour phase on the stage i. index j denotes

compound j. Land V are liquid and vapour flow, x and y are component fraction in the

liquid and vapor phase and hl and hv are he enthalpies.

The vapor-liquid equilibrium has been modeled by assuming ideal gas and using

liquid activity coefficient from the Wilson equation. The vapor flow, V, on stage I have

been modeled using a valve type equation for the pressure drop from one stage to the

next:

Vi = c(Pi-12Pi

2)

0.5

PROCEDURE

1. New case was open, then SRK fluid packageswas selected as current property package

in the fluid package tab.

2. Methanol and water was selected from the component available from the pure

component library box for the component for this system.

3. All the unit was changed to the SI unit.

4. Next simulation environmentwas entered.

5. Then for PFD diagram, the two basic distillation column (DC1, DC2), Tee 2 and valve

was selected as the component that need in this system.

6. All the information given for the Tee 2 was insert.

7. Next the parameterfor DC1 and DC2 was inserted, by clicking 2 times for DC1 and go

to parameter and insert all the information required. Same goes for DC2.

8. After completed the system, the adjust operationwas added in order to apply the heat

integrated for the distillation column.

9. Information was insert of adjust operation, the split ratio of the Tee was adjusted to

make sure the heat duties of DC1 and DC2.

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PROCESS FLOW DIAGRAM

Diagram 1:Process Flow Diagram

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WORK BOOK

DIAGRAM 2: PROCES FLOW FOR DISTILATION COLUMN 1

DIAGRAM 3: WORK BOOK FOR DISTILATION COLUMN 1

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DIAGRAM 4: PROCES FLOW FOR DISTILATION COLUMN 2

DIAGRAM 5: WORK BOOK FOR DISTILATION COLUMN 2

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DIAGRAM 6: WORK BOOK FOR FEED

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ANSWER

There are no manual calculation was involved in this calculation because all the calculation was

done by HYSYS system.

1) What is the value of the split ratio for the feed stream for each DC?

DC 1 : 0.5144

DC 2 : 0.4886

2) What is the molar flow in stream before entering DC1 (in lbmol/hr)?

Stream2: 1381kgmole/h

3) How to reduce pressure in DC2?

Valve is use to reduce the pressure of the steam before enter the DC2 in this HYSYS

simulation system. This happen when molar flowrate of flow in of stream is adjust by the

valve

4) What is the temperature at the bottom of DC1 and DC2 (in oC)?

DC1 :152.1OC

DC2 : 98.85OC

5) Did the process achieve a methanol that free from water? What is the purity of the

methanol? How to increase the purity?

This process only achieve 0.92 mol fraction or 92 percent of pure methanol. To increasethe purity can do by added the compressed vapor stream as heating vapor to an

evaporator or we can increase the number of tray.

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DISCUSSION

Base on the process simulation that had been done using the HYSYS software we can

understand the purpose usage of valve and distillation specification. The production of methanol

was carried out in a moderate pressure synthesis loop by direct hydrogenation of carbon

dioxide. Liquid product was generated and its contains a binary mixture of methanol and water.

The proportion for both is approximately equimolar. Dehydration was achieved usually by

distillation and it provides commercial methanol that was freely by water.

The components at the feed are water and methanol. The components passed through

the splitter and were splitter into two distillation columns. The function of the splitting column is

to achieve high purities in top and bottom outlet. The composition of methanol from distillations

process 0.92. To increase the purity can do by added the compressed vapor stream as heating

vapor to an evaporator in which at least a portion of the methanol/ water mixture to be

separated evaporated. We also can increase the number of tray for each of the distillation

column

This the result showed that produced is almost water free. The split ratio it about 0.5114

and 0.4886 for from distillation column 1 and distillation column 2.For the temperature it state to

change by increasing from stream 1 only 25OC, then at the end the temperature for distillation

column 1 and distillation column 2 is 152.1OCand 98.85OC.