Methanol synthesis operaling conditions

When the reactor system in methanol synthesis operates under kineticalfy controlled conditions, an increase in the circulating rate causes methanol production to decrease. If equilibrium is being achieved, however, one can expect that a 2.53% increase in production will be realized for a 5% increase in circulation and that a 56% increase in production will result from a 10% increase in circulation, and so forth. 

By selection of appropriate operating conditions, the proportion of coproduced methanol and dimethyl ether can be varied over a wide range. The process is attractive as a method to enhance production of Hquid fuel from CO-rich synthesis gas. Dimethyl ether potentially can be used as a starting material for oxygenated hydrocarbons such as methyl acetate and higher ethers suitable for use in reformulated gasoline. Also, dimethyl ether is an intermediate in the Mobil MTG process for production of gasoline from methanol. 

Methanol Synthesis. AH commercial methanol processes employ a synthesis loop, and Figure 6 shows a typical example as part of the overall process flow sheet. This configuration overcomes equiUbtium conversion limitations at typical catalyst operating conditions as shown in Figure 1. A recycle system that gives high overall conversions is feasible because product methanol and water can be removed from the loop by condensation. 

C2. Calculation of Operating conditions and Transport Criteria for the UCKRON Test Problem as a Methanol Synthesis Experiment in the Rotoberty ... 

In the above three processes, the catalysts are all composed of Cu-based methanol synthesis catalyst and methanol dehydration catalyst of AI2O3. The reactors used by JFE and APCI are slurry bubble column, while a circulating slurry bed reactor was used in the pilot plant in Chongqing. It can be foxmd from Table 1 that conversion of CO obtained in the circulating slurry bed reactor developed by Tsinghua University is obvious higher and the operation conditions are milder than the others. 

The reaction of dimethyl carbonate with synthesis gas requires a cobalt-iodide catalyst and operating conditions of 180 C and 4000 psig. The acetaldehyde rate approaches 30 M/hr with selectivities greater than 85%. The productivities are much better than with methanol however, recycle of the CO and methanol back to dimethyl carbonate is very difficult ... 

With the processes currently to obtain methanol, which operate at low pressure (6 to 9 10 Pa absolute), it is possible to eliminate the auxiliaiyxompressor, which was formerly indispensable to introduce the synthesis gas in the requisite operating conditions. 

The present test plant for methanol synthesis is beeing easily operated. Figure 3 shows the rate of production of methanol, i.e., space time yield of methanol (STY), as a function of time on stream over the multicomponent catalyst under the reaction conditions of 523 K, 5 MPa and SV = 5,000 h 10,000 h. The production rate of methanol at SV = 5,000 h was almost the same as that at reaction equilibrium. In the case of SV = 10,000 h the methanol production rate was 600 g/l-cat-h, which is 20% lower than that at reaction equilibrium. No significant difference was observed between data obtained from the present... 

Catalysts based on CuO-ZnO are of great industrial interest because they exhibit high activity for the low temperature-pressure methanol synthesis and the water-gas-shift reactions. It is known that the activity and useful life of catalysts depend mainly on the activation process and the thermal history they experience during the operation. In the low temperature water gas shift (LTWGS) process, prior to reaction, the catalyst is activated by gas reduction to convert copper oxide into metallic copper [1]. It has been observed that reduction conditions affect the activity and the stability of Cu-ZnO catalysts. For instance, sintering and formation of alloys must be avoided in the reduction step because they deactivate the catalyst [2-3] for the water-gas-shift reaction. 

A synthesis gas stream consisting of 67.1% H2, 32.5% CO, and 0.4% CH4 (by mole) is fed into the process described below at a rate of l(X)mol/h. The effluent stream from the reactor is fed into a separator (Fig. P2.13) where the methanol is completely removed, and the unconverted reactants are recycled to the reactor. To avoid the buildup of methane, a portion of the recycled stream is purged. At present operating conditions, the CO... 

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