Weekly Topic: What are the factors that influence the hydrogen-to-carbon ratio at the inlet of the synthesis tower? 2016.06.13--06.18
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Coal chemical technology
Can someone tell me why, when the acid decarboxylation level is high, there’s no reaction during synthesis, but instead the amount of off-gas increases significantly? What’s going on? (The catalyst is no longer in good condition.)
Generally, the H/C of the fresh gas is considered; the H/C at the inlet of the synthesis tower also includes that of the recycle gas. H/C can be classified as active or passive based on the catalyst’s activity; when the activity is low, the active components cannot react effectively, so they merely accumulate within the system. The accumulated active components are not very different from the inert components.
To Wang Xiqing: The fresh gas hydrogen-carbon ratio is an indicator that shows whether the fresh gas meets the required composition ratio for synthesis. Removing carbon dioxide means there is less carbon material available for synthesis, so the amount of gas released during synthesis increases, as hydrogen is consumed without any carbon source available. In the later stage of catalysis, the reaction weakens, the amount of reaction products decreases, and the composition of the output becomes more complex; generally, it is necessary to reduce the load, and methods such as carbon washing are not very effective
1. Catalyst activity； 2. Impact of system cycling
If carbon dioxide levels are high and the amount of crude mixture produced does not change much, then one should look at the changes in the temperature of the synthesis tower and the amount of steam generated. Generally, it is CO + 2H2 = CH3OH + 90.7 kJ per mole, and CO2 + 3H2 = CH3OH + H2 + 49.5 kJ per mole. Judge the reaction based on heat release.