Process for increasing hydrogen content of synthesis gas

摘要

Process for increasing the hydrogen content of a synthesis gas containing one or more sulphur compounds, the synthesis gas including hydrogen, carbon oxides and steam, and having a ratio defined as R═(H2—C02)/(CO+C02)≦0.6 and a steam to carbon monoxide ratio ≦1.8, includes the steps of (i) adjusting the temperature of the synthesis gas; (ii) passing at least a portion of the heated synthesis gas adiabatically through a first bed of sulphur-tolerant water-gas shift catalyst disposed in a first shift vessel at a space velocity ≧12,500 hour−1 to form a pre-shifted gas stream; and (iii) forming a shifted gas stream by subjecting at least a portion of the pre-shifted gas stream to a second stage of water-gas shift in a second shift vessel containing a second bed of sulphur-tolerant water-gas shift catalyst that is cooled in heat exchange with a gas stream including the synthesis gas.

主权项

1. A process for increasing the hydrogen content of a synthesis gas containing one or more sulphur compounds, said synthesis gas comprising hydrogen, carbon oxides and steam, and having a ratio, R, defined as R═(H2—CO2)/(CO+CO2)<0.6 and a steam to carbon monoxide ratio ≦1.8, comprising the steps of (i) heating the synthesis gas, (ii) passing at least a portion of the heated synthesis gas adiabatically through a first bed of sulphur-tolerant water-gas shift catalyst disposed in a first shift vessel at a gas hourly space velocity ≧12,500 hour−1 to form a pre-shifted gas stream to convert 10 to 40% by moles of the carbon monoxide present in the synthesis gas to carbon dioxide, and (iii) forming a shifted gas stream by subjecting at least a portion of the pre-shifted gas stream to a second stage of water-gas shift in a second shift vessel containing a second bed of sulphur-tolerant water-gas shift catalyst that is cooled in heat exchange with a gas stream comprising the synthesis gas.