Methanol, production

The potential of the DMFC, and also the indirect use of methanol given consideration in Chapter 8, relies on the fact that it is a fuel that is produced in bulk at reasonable cost. Methanol is currently produced at the rate of well in excess of 20 000 000 tonnes per year. It has a wide range of uses, but a high proportion (about 40%) is used to make formaldehyde, and about 20% is used in the manufacture of the fuel additive MTBE. Large amounts are used in cleaners, for example, the windshield wash for cars often contains methanol, and an astonishing 250 million US gallons (= 750 000 tonnes) are used in this way each year. Only a very small proportion, about 2%, of methanol is currently used directly as a fuel. 

Methanol can be quite efficiently produced from almost any hydrocarbon fuel. Natural gas is very suitable, as is the well-head gas that is often just burnt off if an oil well is at all remote. The first stage is the simple and well-established process of reacting with steam - a process covered in some depth in Chapter 8 that follows. This produces a mixture of hydrogen, carbon monoxide, and carbon dioxide, the proportions depending on the fuel feedstock, temperature, and pressure. These gases then react to form methanol using either of the reactions 

Because methanol is required in large quantities for industtial purposes, considerable effort has been put into making the production process as efficient as possible. State-of-the-art plants are currently estimated to use about 29 kJ per kilogram of product - this is the lower heating value (LHV) of the feedstock fuel and the energy used to operate the 

Although the great majority of methanol is currently produced using natural gas and other fossil fuels, it can also be produced from renewable biomass. HameUnck and Faaij (2002) give a very fiiU description and analysis of the cost involved in such processes. They show that in a few years such processes should yield methanol with a process efficiency of about 60% and at a cost per Joule similar to current refined diesel and gasoline prices, though at the moment these are higher by a factor of about 3. 

We may conclude that methanol is indeed a low cost and readily available fuel for use in small fuel cells. 

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Figure 2.7 Two alternative reactor designs for methanol production give quite different thermal profiles.

Methanol. If methanol is to compete with conventional gasoline and diesel fuel it must be readily available and inexpensively produced. Thus methanol production from a low-cost feed stock such as natural gas [8006-14-2] or coal is essential (see Feedstocks). There is an abundance of natural gas (see Gas, natural) woddwide and reserves of coal are even greater than those of natural gas. 

Produced from a.tura.1 Ga.s, Cost assessments of methanol produced from natural gas have been performed (13—18). Projections depend on such factors as the estimated costs of the methanol production faciUty, the value of the feedstock, and operating, maintenance, and shipping costs. Estimates vary for each of these factors. Costs also depend on the value of oil. Oil price not only affects the value of natural gas, it also affects the costs of plant components, labor, and shipping. 

Office of Pohcy, Planning, and Analysis, Assessment of Costs and Benefits ofElexible and Alternative Euel Use in the U.S. Transportation Sector, Technical Report 3 (Methanol Production and Transportation Costs) Pub. DOE/P/E—0093, U.S. Department of Energy, Washington, D.C., Nov. 

In the eady 1980s, the process was commercialized in New Zealand to convert offshore natural gas to 2200 m /day (14,000 barrels/day) gasoline. Since then some of the methanol has been diverted from fuel production to chemical-grade methanol production by a dding additional methanol refining capacity. 

A. Stratton, D. F. Hemming, and M. Teper, Methanol Production from Natural Gas or Coal, report no. E4/82, International Energy Agency Coal Research, London, 1982. 

Liquid Fuels via Methanol Synthesis and Conversion. Methanol is produced catalyticaHy from synthesis gas. By-products such as ethers, formates, and higher hydrocarbons are formed in side reactions and are found in the cmde methanol product. Whereas for many years methanol was produced from coal, after World War II low cost natural gas and light petroleum fractions replaced coal as the feedstock. 

MPa (300—400 psig), using a Ni-based catalyst. Temperatures up to 1000°C and pressures up to 3.79 MPa (550 psia) are used in an autothermal-type reformer, or secondary reformer, when the hydrogen is used for ammonia, or in some cases methanol, production. 

High temperature steam reforming of natural gas accounts for 97% of the hydrogen used for ammonia synthesis in the United States. Hydrogen requirement for ammonia synthesis is about 336 m /t of ammonia produced for a typical 1000 t/d ammonia plant. The near-term demand for ammonia remains stagnant. Methanol production requires 560 m of hydrogen for each ton produced, based on a 2500-t/d methanol plant. Methanol demand is expected to increase in response to an increased use of the fuel—oxygenate methyl /-butyl ether (MTBE). 

Feedstock Purification Manufacture of Synthesis Gases Hydrogen, Ammonia, Methanol, product bulletin. United Catalysts, Inc., Louisville, Ky. 

This excess hydrogen is normally carried forward to be compressed into the synthesis loop, from which it is ultimately purged as fuel. Addition of by-product CO2 where available may be advantageous in that it serves to adjust the reformed gas to a more stoichiometric composition gas for methanol production, which results in a decrease in natural gas consumption (8). Carbon-rich off-gases from other sources, such as acetylene units, can also be used to provide supplemental synthesis gas. Alternatively, the hydrogen-rich purge gas can be an attractive feedstock for ammonia production (9). 

Noncatalytic partial oxidation of residual fuel oil accounts for the remainder of world methanol production. Shell and Texaco ate the predominant hcensors for partial oxidation technology (16) the two differ principally in the mechanical details of mixing the feedstock and oxidant, in waste heat recovery, and in soHds management. 

E. Supp and A. T. Weschler, "Conversion of Ammonia Plants to Methanol Production using Lurgi s Combined Reforming Technology", HTChE 1992 SpringMeeting, New Orleans. 

Upgrading Petroleum Residues and Heavy Oils, Murray R. Gray Methanol Production and Use, edited by Wu-Hsun Cheng and Harold H. Kung... 

However, there are several issues with widespread methanol usage. Methanol production from natural gas is relatively inefficient ( 67%), and this largely offsets the vehicular improvement in efficiency and carbon dioxide reduction (since gasoline can be made with "85% efficiency from oil). Additionally, the PEM fuel cell demands very pure methanol, which is difficult to deliver using existing oil pipelines and may require a new fuel distribution infrastructure. 

Ethyl gasoline is developed by General Motors Laboratories in the United States. Du Pont and Commercial Solvents begin synthetic methanol production in the United States. 

Old processes use a zinc-chromium oxide catalyst at a high-pressure range of approximately 270-420 atmospheres for methanol production. 

Methanol has many important uses as a chemical, a fuel, and a building block. Approximately 50% of methanol production is oxidized to... 

Both new catalysts and new processes need to be developed for a complete exploitation of the potential of CO2 use [41]. The key motivation to producing chemicals from CO2 is that CO2 can lead to totally new polymeric materials and also new routes to existing chemical intermediates and products could be more efficient and economical than current methods. As a case in point, the conventional method for methanol production is based on fossil feedstock and the production of dimethyl carbonate (DMC) involves the use of toxic phosgene or CO. A proposed alternative production process involves the use of CO2 as a raw material (Figure 7.1)... 

The production of synthesis gas from natural gas and coal is the basis of the 33 000000 tpa methanol production and is also used in the production of ammonia. After removal of sulfur impurities, methane and water are reacted over a nickel oxide on calcium aluminate catalyst at 730 °C and 30 bar pressure. The reaction is highly endothermic (210 kJmol ) (Equation 6.6). 

Methanol production is carried out over a catalyst containing Cu and Zn oxide on alumina at around 300 °C and 100 atm according to Equation 6.7. It is actually thought that most of the methanol is produced from CO2 formed from reaction of CO with steam (Equation 6.8). 

After peroxide injection, conversion of methane increases fix)m -4% to -10%, methanol production increases 17 fold, and carbon dioxide increases 5 fold, along with modest increases in hydrogen and carbon monoxide. Introduction of hydroxyl radicals to the reactor leads to a greater fi action of product going to methanol as evidenced by methane conversion increasing 2.5 times, whereas methanol production increases 17 times. The increase in carbon dioxide is fiom "deep" oxidation of... 

FIGURE 8. Methanol production from various doped WO3 photocatalysts. WO3 dopants of... 

Methanol production, where CO is added as additive, is very a well-known reaction. The production is carried out in two steps. The first step is to convert the feedstock natural gas into a synthesis gas stream consisting of CO, CO2, H20 and hydrogen. This is usually accomplished by the catalytic reforming of feed gas and steam. The second step is the catalytic synthesis of methanol from the synthesis gas. If an external source of C02 is available, the excess hydrogen can be consumed and converted to additional methanol. 

Reduction of N()2 to NO Reduction of N20 to N2 Copper storage Transcription factor Hydroxylation of Dopa Production of Protoporphyrin IX Hormone signalling Oxidation to methanol Production of signal peptides Copper pump Copper transfer... 

Three-phase reactor systems are ideally suited for methanol production because of the ability to provide intimate contact between the gaseous phase reactants and the solid phase catalysts and to remove the large amounts of heat created by the high heats of reaction. In the three-phase system, an inert liquid phase circulates between the reactor and an external... 

A glass tube fixed-bed reactor was used as a closed static reactor. The cyclotron produced nC-radioisotope (Ti/2=20.4 min) was used for nC-labeled methanol production by radiochemical process. The nC-labeled methanol (shortly nC-methanol, - 3pmol, -600 MBq) was then introduced into 250 mg of zeolite at ambient temperature by He gas flow. Afterwards, equivalent volume of liquid methyl iodide was injected into nC-methanol to have mixture of methanol and methyl iodide and introduced into catalyst for investigation of methyl iodide influence. After adsorption (2 min), the catalyst was heated up to the required temperature. 

Overview of Allowance of Minor Species in the Hydrogen-Rich Product Gas in Gas Engines, Turbines, and Syngas Production for Methanol Production... 

Dong, Y. Steinberg, M., Hynol—an economical process for methanol production from biomass and natural gas with reduced C02 emission. In 10th World Hydrogen Energy Conference, Block, D. L., Veziroglu, T. N. Eds., Beach, Florida, June 20-24,1994, pp. 495-504. 

Higman, C.A.A., Methanol production by gasification of heavy residues, Presented at the IChemE Conference, London, November 22-23, 1995. 

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