Department of Petroleum Engineering and Applied Geophysics

TPG4140 Natural gas

Dimethyl ether production from

carbon dioxide and hydrogen

Pierre-Etienne HUOT-MARCHAND

Trondheim

November 2010

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Abstract The chemical recycling of carbon dioxide to methanol and dimethyl ether (DME) provides a

renewable, carbon-neutral, a source for efficient transportation fuels. DME can be used in

diesel engine, although some modifications of the engine are required. The Icelandic

government has established a long term vision for zero percent hydrocarbon fuel emissions,

and has been working to increase the use of renewable energy. So, Mitsubishi Heavy

Industries (MHI) is planning to open a DME plant in 2014, in Iceland. A two step process is

adopted to produce DME, via methanol, produced from carbon dioxide and hydrogen. To end

that, the flue gas from the ELKEM ferrosilicon plant is fed to the MHI’s CO2 recovery

process, using KS-1 solvent, after sulfur removal in a wet scrubber. Hydrogen is generated by

electrolysis of water. Then, the methanol synthesis is developed by Mitsubishi Gas Chemical

(MGC) and a MHI/MGC superconverter is used. But it is possible to improve methanol

production using natural gas and coal. Hydrogen could be also used more efficiently by

reducing water formation. The DME is then produced using a -Al2O3 catalyst. The good

point is that all environmental regulations are respected and the plant does not discharge any

harmful material to the environment. Besides, the combined emissions from both plants will

be much less than the ELKEM plant emissions. The design capacity is set at 500 Metric Tons

Per Day and supplies half of the Iceland demand.

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List of Contents

Introduction ................................................................................................................................ 1

1. About DME : ...................................................................................................................... 2

2. Presentation of the project in Iceland ................................................................................. 3

2.1 Icelandic government cooperation ............................................................................... 3

2.2 Memorandum Of Understanding (MOU) .................................................................... 4

2.3 Feasibility study ........................................................................................................... 5

2.4 Location ....................................................................................................................... 6

3 Production process ............................................................................................................. 7

3.1 Sulfur removal ............................................................................................................. 7

3.2 CO2 capture .................................................................................................................. 8

3.3 H2 generated by electrolysis ....................................................................................... 9

3.4 Methanol production .................................................................................................. 11

3.5 DME production ........................................................................................................ 13

3.6 Utility and offsite system .......................................................................................... 14

4 Environmental impact analysis ........................................................................................ 15

5 Potential applications and demand of DME in Iceland .................................................... 16

5.1 Potential applications ................................................................................................. 16

5.2 Potential demand ....................................................................................................... 16

Conclusion ................................................................................................................................ 18

References ................................................................................................................................ 19

Appendices ............................................................................................................................... 20

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List of Tables

Table 1 - Diesel oil sold in Iceland in 2008 and equivalent quantity of DME (The Ministry of

Industry et al. 2010) ................................................................................................................. 17

List of Figures

Figure 1 - Carbon dioxide recycling in the methanol economy (George et al. 2009) ............... 2

Figure 2– DME molecule ........................................................................................................... 2

Figure 3 - DME production plant configuration ....................................................................... 7

Figure 4 – Absorption process for CO2 capture (Bolland 2010) ............................................... 9

Figure 5 – PEM Water Electrolysis (Svensson and Møller-Holst 2010) ................................. 11

Figure 6 - DME production flowsheet (West Virginia University 1999) ................................. 14

List of Appendices

Appendix 1 - Energy supply and demand situation in Iceland (IEA 2005) .............................. 20

Appendix 2 – Principle methods for CO2 capture from power plants (Bolland 2010) ............ 20

Appendix 3 – Classification of post-combustion methods for CO2 capture (Bolland 2010) .... 21

Appendix 4 – Choice of most relevant hydrogen sources (Daimler 2010) .............................. 21

Appendix 5 – Simplified process flow sheet for electrolysis (Stoll and Linde 2000) ............... 22

Appendix 6 – Hydrogen production costs (NextHyLight 2010) ............................................... 22

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Introduction

Carbon dioxide is a significant greenhouse gas and is considered as a harmful pollutant and a

major source for global warming. In order to recycle carbon dioxide, many solutions have

been suggested, especially its chemical conversion. One of them is the synthesis of methanol

from CO2 and H2. That is why, it has been demonstrated on a pilot scale in Japan. There is

also significant interest in CO2 to methanol process in China, in Australia and in the European

Union.

The first commercial CO2 to methanol recycling plant should open in 2014, in Iceland. More,

this methanol could be used to produce dimethyl ether (DME), in order to replace fossil fuels

for transport and fishing. Thus, it will increase the use of renewable energy, and it is a good

long term vision. The carbon dioxide recycling in the methanol economy is shown in Figure

1. The main firm involved in the project is Mitsubishi Heavy Industries (MHI), because of its

dependence on Iceland. This will be a large scale test for the benefit of MHI and Iceland, so

MHI should provide and guarantee the technology for 20 years. The costs are evaluated to

278 million Euros (International DME Association 2010) and do not represent the topic of

this report, based on technologies.

Firstly, some information about dimethyl ether will be described. Then, this project in Iceland

will be presented. Thereafter, the production process will be explained in details, especially

about sulfur removal, carbon dioxide capture, hydrogen generation, methanol and DME

production. Finally, an environmental impact analysis will be established followed by a study

of the potential application and demand of DME in Iceland.

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Figure 1 - Carbon dioxide recycling in the methanol economy (George et al. 2009)

1. About DME :

The DME structure-based formula is CH3OCH3 as shown in Figure 2. DME is used in organic

synthesis as a reaction solvent for systems requiring volatile polar solvents. It is a colorless

gas with typical smell. The normal boiling point of DME is -24.9oC. Hence, DME must be

stored in compressed tanks, and this complicates filling. The primary effects of DME are

anesthesia, headache, intoxication, and unconsciousness.

Figure 2– DME molecule

DME has been used as propellant in consumer products. DME can be used in a wide variety

of consumer applications, namely personal care, household products, automotive, paints and

finishes, food products, insect control, animal products, and other related applications.

DME is also promising as a clean-burning hydrocarbon fuel, owing to its high cetane number

(55-60, higher than the 40-55 of conventional diesel fuel), (Arcoumanis et al. 2008), in LPG

Blending and Substitute, Diesel Blending and Substitute, Power Generation and Acetylene

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Substitute. Only moderate modifications are needed to convert a diesel engine to burn DME.

The simplicity of this short carbon chain compound leads during combustion to very low

emissions of particulate matter, NOx, CO. For these reasons as well as being sulfur-free,

DME meets even the most stringent emission regulations in Europe, U.S., and Japan.

There are two ways to produce DME. On the one hand, DME could be produced by a two

step process (conventional process) where the synthesis gas (carbon monoxide and hydrogen)

is converted into DME via methanol. This second reaction is called methanol dehydration.

However, it is also possible to produced methanol by synthesis from carbon dioxide and

hydrogen (see part III.4). On the other hand, a single step process (Haldor Topsoe or JFE

Holdings) could be used.

Nowadays, the research of catalysts for the direct synthesis of DME offers a lot of study

cases. Indeed, this process requires a dual catalyst system which is very complex: it acts as a

methanol synthesis catalyst and a methanol dehydration catalyst in a single unit (between

240°C and 280°C at pressures between 30 and 70 bar). These catalysts are composed of Cu-

ZnO-Al2O3/zeolite. Ferrierte, as zeolite, shows a highest activity and selectivity. The current

works are about the modification of this ferrierte with zirconium.

2. Presentation of the project in Iceland

2.1 Icelandic government cooperation

In this DME project, the Icelandic government and its subordinate organizations of the

Republic of Iceland are represented by:

- The Ministry of Industry, Energy and Tourism (the “Ministry”),

- The National Energy Authority (“NEA”), and

- The Innovation Center Iceland (“ICI”)

One of the goals of the Icelandic government is to obtain a zero percent hydrocarbon fuel

emissions. That is why, the Icelandic government has been actively working to increase the

use of renewable energy, with the result that all of the state’s electricity is generated by

geothermal and hydropower systems today. Renewable energies represent 70% of energy

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consumption in Iceland. The different consumptions of primary energies (15.5x1016

J/yr in

2005) are shown in Appendix - 1 (IEA 2005).

However, Iceland is still importing fossil fuels for transport and fishing. These imports

represent ten percent of the total value of imported goods to Iceland. So, the government is

investigating the possibility of introducing alternative fuels in this field, like DME. Indeed,

any country should use the fuel that is the cheapest, imported or not. Indeed, due to the

abundance of renewable electricity available, the government is interesting in research and

development of electricity based transport, such as hydrogen or fuel-cell vehicles and is

attracting an attention from the world as one of the leading countries of clean-energy uses.

This support of Icelandic Government involves reduction of applicable taxes on the project,

that are taxes on DME sales, corporate tax on the Project Company et cætera, or provision of

subsidies for DME project. More specific data are not available to the public.

2.2 Memorandum Of Understanding (MOU)

The Ministry and some companies agreed to collaborate on investigating potential

introduction of various technologies related to a long term vision of zero percent hydrocarbon

fuel emissions society in Iceland. That is why, on November 21st, 2008 all the parties agreed

to sign a Memorandum Of Understanding (MOU) to study the feasibility of a DME synthesis

plant project for a potential application as an alternative fuel for certain vehicles and fishing

vessels.

The companies represented in this MOU are (The Ministry of Industry et al. 2010):

- Mitsubishi Heavy Industries, Ltd. (“MHI”) is one of the world’s leading heavy

machinery manufacturers and plant engineering contractors. MHI has a diverse line-up

of products and services including shipbuilding, power systems, chemical and

environmental plants, industrial and general machineries, transportation systems,

aerospace equipments, et cætera. MHI has supplied a total of 15 turbines to Icelandic

geothermal power generation plants and supports the country’s energy policy as

mentioned above.

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- Mitsubishi Corporation (“MC”) is one of the world’s leading trading houses

engaged in trading, financing and investment activities in the global industry,

including machinery, petrochemicals, oil and gas, renewable energy, metals, food and

general merchandise. MC, together with MHI, has collaborated with Icelandic power

companies on geothermal power projects for more than 30 years.

- HEKLA (“Hekla”) is a service company, specializing in sales and servicing of

automobiles and heavy machinery. The company’s goal is to lead the field as regards

to customer service and the marketing of goods sold and serviced by the company.

HEKLA represents companies renowned all over the world for quality and reliability,

including Mitsubishi Heavy Industries and Mitsubishi Motors from the year 1979.

HEKLA’s heavy machinery division is located at Klettagardar in Reykjavik. HEKLA

has dealers and service agents in all major towns in Iceland.

- NordicBlueEnergy is an Icelandic company specialized in sustainable and

environmentally friendly projects. Their aim is to merge technical knowledge with

stakeholders to develop financially viable ventures that lead to a better and cleaner

environment for all.

2.3 Feasibility study

The Parties will also evaluate the DME synthesis as a measure to reduce CO2 emission, since

the synthesis DME can be considered as carbon neutral fuel. Because the DME will be

produced from the feed material of both H2, which generated from renewable energy of hydro

and/or geothermal power, and CO2 captured from existing flue gas.

But before starting such project some preliminary studies are needed. Indeed, it is important

to have the following information (The Ministry of Industry et al. 2010):

- An evaluation of the potential feed gas source (amount, composition, impurities etc.) and the

selection of a suitable site for building a DME plant.

- A preliminary design of the carbon dioxide recovery plant and the DME production plant.

- A calculation of the cost of the construction and operation of the DME production plant

based on the preliminary design.

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- The evaluation of the economic feasibility of the DME production compared to existing

energy sources.

- An initial evaluation comparing CO2

emission reduction due to DME production and use

with CCS (Carbon Capture and Storage).

2.4 Location

So, in this project, the synthesis of methanol from carbon dioxide is studied (for the first step

of DME synthesis). It is not really hard to find a plant which currently discharges significant

amounts of CO2 as flue gas to the atmosphere (25 billion tones of CO2 per year). In Iceland,

the plant site near ELKEM ferrosilicon plant in Grondartangi has been selected as the best

place for the DME production plant, because of the following areas (The Ministry of Industry

et al. 2010):

A landfill is planned in the selected area which is currently a coastal shore, according to a

zoning plan. The site is connected to the main road network by already existing roads.

A marine loading/unloading harbor close to the ELKEM plant can be utilised for a marine

loading system and for the construction equipments and materials unloading purposes as well.

An electric power is currently supplied to the area, where the ferrosilicon plant and aluminum

smelter factory are receiving massive amount of electricity. The required power for this

project can be supplied in same manner provided with extra supply capacity and transmission

lines.

The fresh water supply is available for above mentioned existing factories, thus the required

water can be received by the plant provided with extra capacity and supply pipe lines.

Cooling water for the plant shall be sea water taken from a deep fjord sea bed.

On the plant location, there is already an industrialised area so, environmental protection and

natural conservation program has already been implemented, thus only the extra impact by

this plant shall be evaluated. Environmental regulations will be described in later chapter.

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3 Production process

The DME production plant consists of following 4 main process plants and common utility/

offsite system. There are principally a CO2 capture plant, a H2 generation plant, a methanol

plant and a DME plant. The configuration of the DME production plant is shown on the

Figure 3. The design capacity of the DME production is set at 500 MTPD (Metric Tons Per

Day).

Figure 3 - DME production plant configuration

3.1 Sulfur removal

Before feeding the flue gas into the Carbon Capture System, it needs to be pre-treated to

remove sulphur. These pollutants, besides their environmental effect, tend to poison the

catalyst systems. To that end, a Flue Gas Desulfurization system (FGD) is adopted, and five

methods are available: wet scrubbers, spray dry scrubbers, sorbent injection processes, dry

scrubbers and sea water scrubbing.

Wet scrubbers are the most widely used technology (80%) in the FGD market (Bolland 2010).

Then, spray dry scrubbers and sorbent injection systems are used too. Wet scrubbers can

achieve removal efficiencies up to 97-99%, but a treatment of waste water is required.

Wet scrubbers use calcium-, sodium- and ammonium-based sorbents in a slurry mixture with

water. Then, it is injected into the scrubber to react with the sulphur dioxide (SO2) in the flue

gas. The preferred sorbent in operating wet scrubbers is limestone followed by lime, because

of their availability and relative low cost. SO2 is an acid gas and to remove the SO2 from the

flue gases, alkaline is needed. The reaction taking place in wet scrubbing using limestone

(CaCO3) slurry produces calcium sulfite (CaSO3), which is oxidised to form gypsum (CaSO4,

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2H2O). For the contacting between the sorbent and the flue gas, there are a variety of scrubber

designs: spray tower, plate tower, packed tower and fluidised packed tower.

Spray dry scrubbers are limited in size compared to wet scrubbers. Normally the largest plant

size for the spray dry scrubbers is around 200MW. Spray dry scrubbers achieve removal

efficiencies in excess of 90% and up to slightly above 95%.

Dry sorbent injection is a simple method but there are two main disadvantages: to achieve the

same SO2 removal, sorbent required is twice that of a wet scrubber system, and secondly the

large quantities of strongly alkaline waste produced, which is generally disposed of in a

landfill.

The sea water scrubbing system is a simple and inherently reliable one with low capital and

operational costs, which can remove up to 99% of SO2, with no disposal of waste to land.

However, heavy metals and chlorides, if not removed before the SO2 capture, are present in

the water released to the sea.

3.2 CO2 capture

The furnace at Grundartangi produces 45,000 tonnes of 75% ferrosilicon. The off-gases

contain mainly CO and H2 instead of CO2 and have a flowrate of 10,999 Sm3/h. But there are

tar components, sulphur and silica dust too. The sulphur content calculated as SO2 will be

about 800 tonne/year and about 7,000 tonne/year of silica dust. The LHV of the gas mixture

will be about 10.4 MJ/kg, About 84% of the heating value comes from CO, 11% from H2 and

5% from CH4. (Gudmundsson and Hálfdanarson 1999).

There are three different principles for capturing CO2 from power plants (as is shown in

Appendix 2):

- Post-combustion CO2 capture

- Pre- combustion CO2 capture

- Oxy- combustion CO2 capture

In this project, it is a post-combustion CO2 capture. But there are a lot of methods available,

as shown in Appendix 3. The MHI Carbon Capture System technology should be adopted

using chemical absorption, following by an organic capture process with KS-1 solvent. The

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KS-1 flue gas recovery system was developed by the cooperative efforts of Mitsubishi Heavy

Industries, Ltd and Kansai Electric Power Co., Ltd. The KS-1 is described by (Mimura,

Shimojo et al. 1995), (Mimura, Simayoshi et al. 1997), (Iijima 1999), (Mimura and

Matsumoto 2000), and (Shimura 2006).

The recovery technology is officially known as the “KM-CDR Process” (Kansai-Mitsubishi

proprietary CO2 Recovery Process. Commonly, MEA (Monoethanolamine) is used as solvent,

but KS-1 offers the advantages of lower energy requirement and lower solvent degradation

rates. This process is used, in Kedah (Malaysia), in Fukuoka (Japan) and in India.

A flow sheet of the process is shown below in Figure 4. The feed gas enters into the gas

cooler, in order to remove the sulfur (FGD) and sent into absorber. The temperature in the

absorber is between 40°C and 55°C at atmospheric pressure. So, the treated gas as head

product is sent to compressor in order to be transported to the methanol plant. Then, the rich

solvent is recycled using a desorption method. To end that, a stripper is used at temperature

around 100-110 °C.

Figure 4 – Absorption process for CO2 capture (Bolland 2010)

3.3 H2 generated by electrolysis

Electrolysis uses an electric current to split water into hydrogen and oxygen. Any available

energy source (alternative energies such as solar, wind, geothermal, and atomic energy) can

be used for the electricity required (can result in zero greenhouse gas emissions). However,

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many other ways could be used to produce H2, such as natural gas reforming, biomass

gasification, nuclear electrolysis, coal gasification and hydrogen as a byproduct. The main

advantages of the renewable electrolysis are the good energy and CO2 balances at the same

time, the renewable energies available in Iceland and the fact that hydrogen is a means of

storage for excess electricity. Advantages of other methods are available in the Appendix 4

(Daimler 2010).

Electrolyzers consist of an anode and a cathode separated by an electrolyte. There are three

kinds of electrolysers: polymer electrolyte membrane (PEM) electrolyzers, alkaline

electrolyzers and solid oxide electrolyzers. An important criterion to choose is the temperature

of the water, because when it increases, less electricity is required to split water into hydrogen

and oxygen, which reduces the total energy required. (solid oxide electrolysers operate at

500°C–800°C, PEM electrolyzers operate at 80°C–100°C, and alkaline electrolyzers operate

at 100°C-150°C) (US Department of energy 2008).

In a polymer electrolyte membrane (PEM) electrolyzer, the electrolyte is a solid specialty

plastic material. Alkaline electrolysers and PEM electrolysers are quite the same, just the

solution changes. Water reacts at the anode to form oxygen and protons (A). The electrons

flow through an external circuit and the hydrogen ions selectively move across the PEM to the

cathode. Then, protons combine with electrons from the external circuit to form H2 (C).

These reactions are shown in Figure 5 (Svensson and Møller-Holst 2010). A more complete

industrial process is available in Appendix 5 (Stoll and Linde 2000).

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Figure 5 – PEM Water Electrolysis (Svensson and Møller-Holst 2010)

The new challenges about this technology are reducing the capital cost of the electrolyzer and

improving energy efficiency. In order to avoid the cost of the compressor, for transport and

storage, researchers are working on integrated compressors into the electrolyser. Hydrogen

production costs for some technologies are available in the Appendix 6 (NextHyLights, 2010).

3.4 Methanol production

3.4.1 Catalytic hydrogenative conversion of carbon dioxide to methanol

The main reaction (1) to produce methanol from CO2 is the catalytic regenerative conversion

of CO2 with hydrogen. It is planned to use this process in Iceland. In this methanol synthesis

unit, Mitsubishi Gas Chemical (MGC) developed a methanol synthesis catalyst and some

MHI/MGC SUPERCONVERTER (SPC) are used. The crude methanol is produced in the

SUPERCONVERTER.

Catalysts are based on metals and their oxides, in particular the combination of copper and

zinc oxide. (Lurgi AG, a leader in the methanol synthesis process, developed the best catalyst

for this reaction). Increasing temperatures rapidly decrease catalyst activity so that isotherms

need to be carefully controlled. The selectivity to methanol is excellent (around 99.8%) with

an operating temperature around 260 °C (conversion of about 95%), (Saito 1998) and (US

DOE 2003).

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CO2 + 3 H2 CH3OH + H2O H298K = -11.9 kcal/mol (1)

3.4.2 Improved methanol production from natural gas and coal

3.4.2.1 Carnol process

To reduce CO2 emission in the atmosphere, it is possible to use fossil fuels. This process is

called the “Carnol process” where H2 is produced by thermal decomposition of CH4 with

carbon formed as a byproduct (2). This H2 reacts with CO2 recovered from emission of the

fossil fuel power plant to produce methanol (3). So, the net emission of CO2 is close to zero,

because CO2 released by the methanol used as a fuel is recycled from existing emission

sources. About the carbon formed, it could be stored (more easily than the CO2) and reused.

Methane thermal decomposition CH4 C + 2 H2 H298K = 17.9 kcal/mol (2)

Methanol synthesis CO2 + 3 H2 CH3OH + H2O (3)

Overall Carnol process 3 CH4 + 2 CO2 2 CH3OH + 2 H2O + 3 C

3.4.2.2 Methane decomposition & dry reforming

In this process, the environmental benefit is lower than the Carnol process, but it is better for

the economic cost. This process results in the combination of CH4 decomposition (4) and dry

reforming (5). The products are methanol and carbon (6). The dry reforming does not

involved steam, CO2 is reacted with natural gas to produce syngas (more endothermic than

steam reforming). With the dry reforming, natural gas resources are used more efficiently.

However, this syngas composition is not suitable for the production of methanol using

existing technology in which a H2/CO ratio close to 2 is needed.

CH4 C + 2 H2 (4)

CH4 + CO2 2 CO + 2 H2 H298K = 59 kcal/mol (5)

2 CH4 + CO2 2 CO + 4 H2 + C 2 CH3OH + C (6)

3.4.2.3 Steam reforming & dry reforming

This way overcomes the previous disadvantage because it is possible to get a H2/CO ratio

close to 2. It uses steam reforming with a H2/CO ratio of 3 (7). The combination of steam and

dry reforming (8) can be used for the conversion of CO2 emissions from fossil fuels burning

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power plant. It is also advantageous for reforming natural gas and geothermal sources which

often are accompanied by substantial amounts of CO2.

Steam reforming 2 CH4 + 2 H2O 2 CO + 6 H2 (7)

Dry reforming CH4 + CO2 2 CO + 2 H2

Bireforming 3 CH4 + 2 H2O + CO2 4 CO + 8 H2 4 CH3OH (8)

3.4.3 Combining reduction and hydrogenation of CO2

The main reaction (1) produces water as a byproduct, but a third of the hydrogen and the

electricity are used to produce it. So, to use hydrogen more efficiently, initial chemical or

electrochemical reduction of CO2 to CO (9) to minimize water formation can be considered.

Reverse Boudouard reaction CO2 + C 2 CO H298K = 40.8 kcal/mol (9)

This coal gasification can be used at temperature above 800°C (using fluidized bed reactors

and molten salt media). The direct conversion of CO2 to CO using a thermochemical cycle

and solar energy is also being studied (Ga´lvez et al. 2008), (Travnor and Jensen 2002). Then,

methanol is obtained by adding hydrogen (10). It is also possible to produce methanol from

CO2 and H2O with an electrochemical process.

CO + 2 H2 CH3OH (10)

3.5 DME production

To produce DME, the methanol is dehydrated and the reaction (11) is carried out catalytically

over varied solid acids such as alumina or phosphoric acid modified -Al2O3.

2 CH3OH CH3OCH3 + H2O (11)

The flow sheet is shown below in Figure 6, and explanations are following. Crude methanol

is pumped up to 16.8 atm and combined a methanol recycle stream. The mixture is then sent

into heat exchanger E-101 where it is heated to a temperature of 250°C before it is sent to the

reactor, R-101, to form DME. The reaction is slightly exothermic and the reaction products

14

are heated to approximately 365°C before leaving the reactor. The reactor effluent is cooled in

E-102 and then throttled to 10 atm before entering the first distillation column T-101. Here,

the DME is separated as head product. The bottom product, containing the methanol and the

water, is throttled to 6.9 atm and sent to the second distillation column T-102 to eliminate the

waste components. The waste components exit as distillate, and have to be cleaned in a waste

treatment facility. The water and methanol exit as the bottoms stream. This stream is then

throttled to 1 atm and then sent to the last distillation column T-103 where the water and

methanol are separated. The water exits the bottom of the distillation column, and is sent to

waste treatment. The methanol exits the column as distillate and is pumped up to 16.8 atm and

recycled back to mix with fresh methanol.

Figure 6 - DME production flowsheet (West Virginia University 1999)

3.6 Utility and offsite system

All around this DME plant in Iceland, some basic utilities are needed. It consists of the

following (not exhaustive list) (The Ministry of Industry et al. 2010):

- The electrical power supply will be from an outside system (from the national grid or

a power station). The electricity demand of the plant exceeds the currently available

surplus power, so a new power generation and supply system will be required.

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- The cooling system for the plant will be a closed circuit of clean water (sea water)

- The raw water will be from an outside water supply network and fed to inside water

treatment for users.

- The effluent water will be discharged to the sea after treatment

- Steam will be generated at the ELKEM plant utilizing the waste heat of the flue gas

stream.

- Boiler feed water will be treated in a de-mineralized water treatment unit and sent to

ELKEM for steam generation.

- A Flare system for effluent gases.

- An incinerator unit for effluent flammable liquids.

- Product storage will be provided for both methanol and DME.

4 Environmental impact analysis

The plant emission has been evaluated based on the conceptual design of the plant. The good

point is that all environmental regulations are respected and the plant does not discharge any

harmful material to the environment.

Furthermore, by treating the flue gas from the ELKEM plant, which is currently discharged to

the atmosphere, the combined emissions from both plants will be much less, and thus the

overall environmental impact is improved (The Ministry of Industry et al. 2010). Also

according to the Mannvit assessment, the emission to air and discharges to sea seem to be a

minor issue and the project could be started.

About the waste water, in the Flue Gas Desulfurization, it is flowing into the ocean. A 10°C

rise in the water temperature will only raise a bit the temperature of the sea. The other waste

water stream are not so good, slightly higher maximum values from undesirable. But as the

volume of the stream is low, this variance should be addressed in the Environmental

Operating Permit, and is not expected to pose any problems. DME production is not really a

part of the document on Large Volume Organic Chemicals or any other documents. Only the

general issues and guidance of the documents will apply to this type of process.

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5 Potential applications and demand of DME in Iceland

5.1 Potential applications

As presented before, the consumption of diesel oil as transportation fuel for ships and

automobiles in Iceland is too important for the Icelandic government. DME is a good

substitute for diesel oil, and it has been widely used in China. Although some modification of

engine, such as replacing the fuel injection pumps and fuel tank, is required. The main

potential applications for replacement of DME are listed as follows;

- Diesel fuel for automobile

- Diesel fuel for ships

- LPG blending component for households and industry

- Coal / Natural gas / Oil for power generation

5.2 Potential demand

The major potential consumers of DME will be Ships and automobiles because there is no

demand for power generation or LPG substitute in the country. The daily average diesel oil

sales for ships and vehicles, and the equivalent quantity of DME are shown in Table 1 (The

Ministry of Industry et al. 2010).

More than 60% of this diesel oil is consumed by ships and the balance by vehicles. The fuel

consumption in Reykjavik represents 50% of the Icelandic fuel demand. The total Icelandic

demand of DME is 972 MTPD (equivalent to 722 MTPD of diesel), and the design capacity

of the future DME plant was set at 500 MTPD (Metric Tons Per Day). So, it will allow

producing around 50% of the DME demand. To ensure the total demand, 222 MTPD of diesel

are needed (decreasing by 70% the amount of diesel). Indeed, the heating value of the DME is

lower and 35% more of fuel, in mass, are needed. In addition, with this project, 150 to 250

jobs should be provided.

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Table 1 - Diesel oil sold in Iceland in 2008 and equivalent quantity of DME (The Ministry of

Industry et al. 2010)

Ships Trucks Total Ships Trucks Total

ton diesel/day ton DME/day

Reykjavik 222 139 361 299 187 486

West 22 28 50 30 37 67

West fjord 22 8 31 30 11 41

North 67 42 108 90 56 146

East 67 19 86 90 26 116

South 44 42 86 60 56 116

444 278 722 598 374 972

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Conclusion

This report only based on scientific elements describes a new dimethyl ether production

complex and its four main plants:

- a carbon dioxide capture plant, where the flue gas from the ELKEM ferrosilicon plant

is fed to the MHI’s CO2 recovery process.

- a hydrogen generation plant, where hydrogen is generated by electrolysis of water.

- a methanol plant, where a MHI/MGC superconverter is used. Some methods have

been presented in order to improve the methanol production.

- a dimethyl ether plant, where the crude methanol is converted using a -Al2O3 catalyst.

Besides, the ELKEM plant is the best place in Iceland thanks to its offsite system. And all

environmental regulations are respected and emissions are lower than the ELKEM plant.

In addition, the production of alternative renewable energy can reduce foreign currency

expenditure to import diesel oil and using Carbon Capture System will reinforce the vision

of a zero emission society. This project will supply half of the Iceland demand and will be

a large scale test for the benefit of MHI and Iceland.

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References

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Report; Prepared by Air Products Liquid Phase Conversion Company for the US DOE National

Energy Technology Laboratory, 2003.

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Appendices

Appendix 1 - Energy supply and demand situation in Iceland (IEA 2005)

Appendix 2 – Principle methods for CO2 capture from power plants (Bolland 2010)

21

Appendix 3 – Classification of post-combustion methods for CO2 capture (Bolland 2010)

Appendix 4 – Choice of most relevant hydrogen sources (Daimler 2010)

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Appendix 5 – Simplified process flow sheet for electrolysis (Stoll and Linde 2000)

Appendix 6 – Hydrogen production costs (NextHyLight 2010)