Methanol economics

Snpp, E, "Convert methanol economically". Hydrocarbon Processing 63 (7) 34 C-J (1984). 

Summarising what has been discussed in section 4, we present the global production of some alternatives in Table V. The scale of demand for gasoline calls for huge investment to replace gasoline by, e.g., methanol. Economic factors as well as the low efficiency of methanol production (Tkble IV) indicate that careful consideration is required before vigorously pursuing alternatives like these. 

Bromination of methane is exothermic but less exothermic than chlorination The value calculated from bond dissociation energies is AH° = -30 kJ Al though bromination of methane is energetically fa vorable economic considerations cause most of the methyl bromide prepared commercially to be made from methanol by reaction with hydrogen bromide... 

Office of Mobile Sources, Analysis of the Economic and Environmental Effects of Methanol as an Automotive Euel, U.S. Environmental Protection Agency, Ann Arbor, Mich., Sept. 1989. 

Chemicals have long been manufactured from biomass, especially wood (sHvichemicals), by many different fermentation and thermochemical methods. For example, continuous pyrolysis of wood was used by the Ford Motor Co. in 1929 for the manufacture of various chemicals (Table 20) (47). Wood alcohol (methanol) was manufactured on a large scale by destmctive distillation of wood for many years until the 1930s and early 1940s, when the economics became more favorable for methanol manufacture from fossil fuel-derived synthesis gas. 

Ethers, such as MTBE and methyl / fZ-amyl ether (TAME) are made by a catalytic process from methanol (qv) and the corresponding isomeric olefin. These ethers have excellent octane values and compete on an economic basis with alkylation for inclusion in gasoline. Another ether, ethyl tert-huty ether (ETBE) is made from ethanol (qv) and isobutylene (see Butylenes). The cost and economic driving forces to use ETBE vs MTBE or TAME ate a function of the raw material costs and any tax incentives that may be provided because of the ethanol that is used to produce it. 

Commercial VPO of propane—butane mixtures was in operation at Celanese Chemical Co. plants in Texas and/or Canada from the 1940s to the 1970s. The principal primary products were acetaldehyde, formaldehyde, methanol, and acetone. The process was mn at low hydrocarbon conversion (3—10%) and a pressure in excess of 790 kPa (7.8 atm). These operations were discontinued because of various economic factors, mainly the energy-intensive purification system required to separate the complex product streams. 

There are some chemicals that can be made economically from coal or coal-derived substances. Methanol and CO are used to make acetic anhydride and acetic acid. Methanol itself can be made from synthesis gas over a copper-2inc catalyst (see Feedstocks, coal chemicals). 

Much of the work with regard to this process was done by the French Petroleum Institute (113) and by the Kuraray Co. (108). In the CIS, a sinulat process which begins with cmde C s was developed (114). A one-step process that begins with isobutylene and methanol has been disclosed (108,115). This process is beheved to have significant economic advantages over the original route. 

Economic Aspects. Terephthahc acid and dimethyl terephthalate are usually sold under long-term contracts. Pricing information is at times pubhshed but actual contract prices are not revealed. Price data pubhshed in 1992 were 0.60/kg for terephthahc acid and 0.57/kg for dimethyl terephthalate (42). The price is mainly influenced by the price of -xylene. The price of terephthahc acid is more than dimethyl terephthalate because a kilogram of it produces 17% more polyester. The price of dimethyl terephthalate takes this factor plus a credit for the methanol generated during polyester production into consideration. 

The selective alkylation of toluene with methanol to produce -xylene as a predominant isomer can be achieved over shape-selective catalysts (99—101). With a modified ZSM-5 zeoHte catalyst, more than 99% -xylene in xylene isomers can be produced at 550°C. This -xylene concentration exceeds the equiHbrium concentration of 23% (99). The selective synthesis of -xylene using relatively low cost toluene is economically attractive however, this technology was not commercialized as of 1991. 

The performance of many metal-ion catalysts can be enhanced by doping with cesium compounds. This is a result both of the low ionization potential of cesium and its abiUty to stabilize high oxidation states of transition-metal oxo anions (50). Catalyst doping is one of the principal commercial uses of cesium. Cesium is a more powerflil oxidant than potassium, which it can replace. The amount of replacement is often a matter of economic benefit. Cesium-doped catalysts are used for the production of styrene monomer from ethyl benzene at metal oxide contacts or from toluene and methanol as Cs-exchanged zeofltes ethylene oxide ammonoxidation, acrolein (methacrolein) acryflc acid (methacrylic acid) methyl methacrylate monomer methanol phthahc anhydride anthraquinone various olefins chlorinations in low pressure ammonia synthesis and in the conversion of SO2 to SO in sulfuric acid production. 

Feed Composition. Feed composition has a substantial effect on the economics of a distillation. Distillations tend to become uneconomical as the feed becomes dilute. There are two types of dilute feed cases, one in which the valuable recovered component is a low boiler and the second when it is a high boiler. When the recovered component is the low boiler, the absolute distillate rate is low but the reflux ratio and the number of plates is high. An example is the recovery of methanol from a dilute solution in water. When the valuable recovered component is a high boiler, the distillate rate, the reflux relative to the high boiler, and the number of plates all are high. An example for this case is the recovery of acetic acid from a dilute solution in water. For the general case of dilute feeds, alternative recovery methods are usually more economical than distillation. 

Ethyl Tertiary-Butyl Ether. Similar to methanol in the MTBE reaction, ethanol can react with isobutylene to produce ETBE. Which alcohol is used to make the ether is highly dependent on the relative cost of the alcohols. To make ethanol more economically competitive with methanol, the federal tax credit for biomass-based ethanol used in fuel also appHes to ethanol used to make ETBE in the United States (24). 

Methanol to Ethylene. Methanol to ethylene economics track the economics of methane to ethylene. Methanol to gasoline has been flilly developed and, during this development, specific catalysts to produce ethylene were discovered. The economics of this process have been discussed, and a catalyst (Ni/SAPO 34) with almost 95% selectivity to ethylene has been claimed (99). Methanol is converted to dimethyl ether, which decomposes to ethylene and water the method of preparation of the catalyst rather than the active ingredient of the catalyst has made the significant improvement in yield (100). By optimizing the catalyst and process conditions, it is claimed that yields of ethylene, propylene, or both are maximized. This is still in the bench-scale stage. 

Extraction from Aqueous Solutions Critical Fluid Technologies, Inc. has developed a continuous countercurrent extraction process based on a 0.5-oy 10-m column to extract residual organic solvents such as trichloroethylene, methylene chloride, benzene, and chloroform from industrial wastewater streams. Typical solvents include supercritical CO9 and near-critical propane. The economics of these processes are largely driven by the hydrophihcity of the product, which has a large influence on the distribution coefficient. For example, at 16°C, the partition coefficient between liquid CO9 and water is 0.4 for methanol, 1.8 for /i-butanol, and 31 for /i-heptanol. 

Silica gel, per se, is not so frequently used in LC as the reversed phases or the bonded phases, because silica separates substances largely by polar interactions with the silanol groups on the silica surface. In contrast, the reversed and bonded phases separate material largely by interactions with the dispersive components of the solute. As the dispersive character of substances, in general, vary more subtly than does their polar character, the reversed and bonded phases are usually preferred. In addition, silica has a significant solubility in many solvents, particularly aqueous solvents and, thus, silica columns can be less stable than those packed with bonded phases. The analytical procedure can be a little more complex and costly with silica gel columns as, in general, a wider variety of more expensive solvents are required. Reversed and bonded phases utilize blended solvents such as hexane/ethanol, methanol/water or acetonitrile/water mixtures as the mobile phase and, consequently, are considerably more economical. Nevertheless, silica gel has certain areas of application for which it is particularly useful and is very effective for separating polarizable substances such as the polynuclear aromatic hydrocarbons and substances... 

Generally, an alcohol or one of the glycols—usually methanol, ethylene glycol (EG), or diethylene glycol (DEG)—is injected as an inhibitor. All may be recovered and recirculated, but the economics of methanol recovery will not be favorable in most cases. 

See also Efficiency of Energy Use, Economic Concerns and Engines Fuel Cells Fuel Cell Vehicles Hydrogen Methanol Synthetic Fuel. 

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