Process and device for preparing H2 and CO by co-transformation of CH4 and CO2

Abstract

The invention relates to a method for preparing H2 and CO through the cotransformation of CH4 and CO2 and a device thereof, which pertain to the technical filed of petrochemical industry and coal-chemical industry. The reactant gases CH4 and CO2 are premixed by mole ration of 1:1 to 4:1, sent into a plasma reactor for reaction, separated by a polysulphone membrane H2 separator and then separated by a CO separator, with the left gas sent back to be premixed with feed gas, thereby obtaining H2 and CO by circulative preparation. A gas premixer (1), a plasma reactor (2), an H2 separator (3) and a CO separator (4) are connected in sequence, and the outlet that does not separates gas of the CO separator is connected with the inlet of the premixer. The invention also provides a method and a device that include the steps of reaction-separation-separation-reaction-separation-separation for twice or a plurality of times. The method and the device of the invention avoid terminated reaction caused by inactivated catalyst and realize the preparation of H2 and CO at low temperature, effectively reduce the energy consumption and have high transformation rate of CH4 and CO2 and good product selectivity.

Description

technical field [0001] The present invention relates to a low temperature CH 4 and CO 2 Co-transformation to produce H 2 The method and device for CO and CO belong to the technical fields of petrochemical and coal chemical industry. Background technique [0002] CH 4 and CO 2 is the main greenhouse gas, CH 4 CO 2 The reforming reaction can not only realize the simultaneous chemical conversion of the two, but also produce a large amount of synthesis gas for Fischer-Tropsch synthesis and other processes. [0003] At present, the research mainly focuses on the following aspects: thermodynamics research, catalyst loading metal, carrier and additive research, carbon deposition behavior research and reaction kinetics research, etc. According to thermodynamic calculations, it can be known that the reaction is a strong endothermic reaction, at least above 600°C to generate syngas, and to reach a higher CH at above 850°C 4 and CO 2 Therefore, the conventional catalyst cataly...

AI Technical Summary

Problems solved by technology

For the catalytic reforming reaction of methane, the metals supported on the catalyst, that is, the active components, are mostly transition metals of Group VIII, and nickel metal is the most commonly used, but this type of catalyst has a big drawback, which is very easy to Carbon deposition causes catalyst deactivation, thereby terminating the reaction. Usually, some alkaline earth metal or rare earth metal oxides are added as additives to reduce carbon deposition. Using noble metals as active components can effectively inhibit carbon deposition, but the use of noble metals causes A substantial increase in catalyst costs

CH 4 and CO 2 As a substance with high carbon content, the reaction between the two will inevitably cause greater carbon deposition and deactivation problems

[0004] At present, studies have shown that the use of plasma properties can achieve CH at low temperature 4 and CO 2 conversion, but due to the nature of the plasma itself, the process has poor selectivity for products and limited conversion

[0005] The traditional methane dry gas reforming process has the following disadvantages: the reaction can only occur at high temperature, requiring high energy input, resulting in CO 2 The cost of the chemical conversion process increases; the requirements for the catalyst are very high, which not only requires the carrier to have high thermal stability, but also overcome the reaction termination caused by carbon deposition

[0006] Universal plasma-catalyzed CH 4 and CO 2 Chemical conversion has the following disadvantages: through a plasma reactor operated at atmospheric pressure, the product selectivity is poor, the synthesis gas yield is low and the feed gas conversion rate is low, and some reactors that use radio frequency or microwave discharge to promote conversion need to operate at a lower temperature. Operating under negative pressure not only increases the requirements for equipment but also affects the throughput of the reactor, which is not conducive to industrial scale-up

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