Synthesis gas

Claim 1

In a continuous process of producing a gas stream comprising hydrogen and carbon oxides having a ratio R in the range 1.5 to 2.22 where R is defined as ##EQU2## where H 2 , CO, and CO 2 represent the number of moles of these gases in said gas stream, by the steps of (a) reacting a normally gaseous hydrocarbon feedstock with oxygen, the proportion of oxygen being less than sufficient for complete combustion, but sufficient to avoid substantial by-product carbon formation, whereby a hot gas stream at a temperature in the range 1093°-1260° C. is produced; (b) mixing a further amount of said normally gaseous hydrocarbon into said hot gas stream; (c) reacting the whole of the resulting gas mixture adiabatically over a steam reforming catalyst comprising a Group VIII metal on a heat resistant support, whereby to increase the ratio R from that of said hot gas and to decrease the temperature of the gas mixture to give a product gas at a temperature in the range 750°-950° C. and at a pressure in the range 5 to 50 bar abs.; the improvement whereby a compressed gas stream that is suitable for methanol synthesis at a pressure in the range 20 to 120 bar abs. is provided by (i) in step (b) adding steam as well as said further hydrocarbon to said hot gas stream whereby the product gas produced in step (c) contains unreacted steam; (ii) cooling the product gas produced in step (c) by expansion in a turbine; (iii) cooling the expanded gas produced in step (ii) further and separating water, but not carbon dioxide, therefrom; and (iv) compressing the resultant water-depleted gas to said methanol synthesis pressure in a compressor powered by said turbine.