Methanol conventional synthesis

Direct conversion of methane [74-82-8] to methanol has been the subject of academic research for over a century. The various catalytic and noncatalytic systems investigated have been summarized (24,25). These methods have yet to demonstrate sufficient advantage over the conventional synthesis gas route to methanol to merit a potential for broad use. 

Application To produce ammonia from natural gas, LNG, LPG or naphtha. Other hydrocarbons—coal, oil, residues or methanol purge gas— are possible feedstocks with an adapted front-end. The process uses conventional steam reforming synthesis gas generation (front-end) and a medium-pressure (MP) ammonia synthesis loop. It is optimized with respect to low energy consumption and maximum reliability. The largest single-train plant built by Uhde with a conventional synthesis has a nameplate capacity of 2,000 metric tons per day (mtpd). For higher capacities refer to Uhde Dual Pressure Process. 

Chloromethyl methyl ether, 1, 132-135 5, 120 7, 61-62. The conventional synthesis produces the potent carcinogen bis(chloromethyl) ether as a by-product. A new preparation (equations I and II) is free from this drawback. Methanol is required only in a catalytic amount, since it is regenerated as the ether is formed. The by-product is methyl acetate. 

Chem Systems Inc. has been developing a three phase reaction system for methanol synthesis since the mid 1970 s (ref. 28). The original concept incorporated a liquid-fluidized-bed reactor. This research, which was funded by the Electric Power Research Institute, used particles of a heterogeneous catalyst, obtained by crushing pellets of a commercial Cu-ZnO-AljO type catalyst, which was fluidized by a circulating inert hydrocarbon liquid such as a mineral oil. One of the major benefits of the process over conventional synthesis is claimed (ref. 28) to be excellent temperature control of the reactions so that higher per pass conversions can be achieved, thereby reducing... 

Other interesting non-heme oxygenases are the methane monooxygenases (MMOs) [53]. These enzymes can transform methane into methanol, a reaction extremely difficult to carry out using conventional synthesis. They are also able... 

The formation of methanol from synthesis gas can be described by the two independent reverse reactions that were given in section 5.1.1.6. for the methanol splitting process by high temperatures or steam reforming. In the conventional method, a mixture of CO, CO2, and H2 is compressed to about 10 MPa and introduced into a fixed-bed catalytic reactor at temperatures of 220 - 280 °C and pressures of 5 - 20 MPa [27]. 

The reactions are exothermal and volume-reducing, thus low temperatures and high overpressures are desirable. A catalyst is required to maximize methanol output. The specific consumption is 2300 Nm of CO and H2 per ton of methanol. A processing scheme has been proposed by Lurgi (see Fig. 7-1). Nowadays conventional synthesis reactors have a capacity of up to 3(XX) t/d of methanol. 

Researchers at the Pennsylvania State University have reported direct catalytic conversion of methane into acetic acid under relatively mild conditions. Conventional synthesis of acetic acid from methanol currently involves a three stage process, including ... 

Scheme 7.21 Conventional synthesis of DME via methanol production and dehydration (two-step) and direct synthesis via CO2 hydrogenatirai (one-step)...

The U.S. Department of Energy has funded a research program to develop the Hquid-phase methanol process (LPMEOH) (33). This process utilizes a catalyst such as copper—zinc oxide suspended in a hydrocarbon oil. The Hquid phase is used as a heat-transfer medium and allows the reaction to be conducted at higher conversions than conventional reactor designs. In addition, the use of the LPMEOH process allows the use of a coal-derived, CO-rich synthesis gas. Typical reactor conditions for this process are 3.5—6.3 MPa (35—60 atm) and 473—563 K (see Methanol). 

Another example of potassium as a promoter is in the hydrogenating of CO to give methanol directly, as mentioned earlier [M. Maack, H. Friis-Jensen, S. Sckerl, J. H. Larsen and I. Chorkendorff Top. Catal. 22 (2003) 161]. Here it works as a promoter for CO hydrogenation, but with conventional methanol synthesis great efforts are made to avoid the presence of alkalis in the catalyst as they tend to ruin the selectivity by promoting the production of higher alcohols, i.e. the surface becomes too reactive. Thus great care has to be exercised to achieve the optimal effects. 

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