Process to prepare synthesis gas

Abstract

A process for the preparation of hydrogen and carbon monoxide containing gas from a carbonaceous feedstock involving: (a) partially oxidizing a feedstock in a tubular partial oxidation reactor vessel to obtain a mixture of hydrogen and carbon monoxide; (b) catalytically steam reforming a feedstock in a convective steam reformer which is a tubular reactor with one or more tubes containing a reforming catalyst, wherein the steam to carbon molar ratio of the feed to step (b) is below 1; (c) feeding the steam reformer product to the upper end of the partial oxidation reactor to obtain a mixture of the effluent of step (a) and the steam reformer product; and (d) providing heat for step (b) by convective heat exchange between the mixture obtained in step (c) and the steam reformer reactor tubes to obtain a hydrogen and carbon monoxide containing gas having a reduced temperature.

Description

FIELD OF THE INVENTION [0001] The invention is directed to a process to prepare a mixture comprising carbon monoxide and hydrogen from a carbonaceous feed by performing a partial oxidation reaction and an endothermic steam reforming reaction. BACKGROUND OF THE INVENTION [0002] EP-A-168892 describes an endothermic steam reforming reaction, which is carried out in a fixed bed situated in at least one pipe in which a temperature of between 800 and 950° C. is maintained by routing at least part of the hot product gas from a partial oxidation reaction along the pipe(s). According to this publication the combined partial oxidation and endothermic production of synthesis gas result in a better yield of synthesis gas, an increased H2 / CO ratio, a lower usage of oxygen per m3 of synthesis gas product obtained and a lower capital cost of the plant for the production of CO and H2-containing gas mixtures (as compared to partial oxidation). [0003] A reactor and process for performing a steam refo...

AI Technical Summary

Benefits of technology

This approach allows for operation at a lower steam to carbon ratio, reducing methane content in the synthesis gas and enabling its effective use in Fischer-Tropsch processes by optimizing temperature and catalyst conditions, thereby improving conversion efficiency and reactor space utilization.

Problems solved by technology

A disadvantage of the processes of the prior art is that the obtained synthesis gas, carbon monoxide and hydrogen mixture, comprises of a relatively high content of steam.

This steam is not desired, especially when the synthesis gas is to be used in a Fischer-Tropsch synthesis.

However this will result in that less methane will be converted in the CSR reactor resulting in a synthesis gas containing a high level of methane.

Although such levels may be acceptable for some processes, if the synthesis gas is to be used as feed to a Fischer-Tropsch process the presence of methane is not desirable because it will be present as an inert occupying reactor space.

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