Patent ID: 7655825

Claim:
A method for producing a synthetic fuel from a gas mixture comprising an oxygenate wherein the oxygenate is methanol and/or dimethyl ether and/or another oxygenate, which comprises the steps of: (a) heating the gas mixture comprising an oxygenate wherein the oxygenate is methanol and/or dimethyl ether and/or another oxygenate, to a temperature of 300 to 600° C. in the presence of steam to produce olefins having 2 to 8 carbon atoms and saturated hydrocarbons; (b) separating the olefins having 2 to 8 carbon atoms from the saturated hydrocarbons formed during step (a) and the steam, and recycling the saturated hydrocarbons and the steam back to the beginning of step (a); (c) oligomerizing the olefins having 2 to 8 carbon atoms at elevated pressure to form higher olefins having 10 to 20 carbon atoms resulting in a reaction mixture of the higher olefins, olefins having 2 to 8 carbon atoms, and a gas stream of saturated hydrocarbons; (d) separating the olefins having 2 to 8 carbon atoms from the reaction mixture in step (c) and recycling the olefins having 2 to 8 carbon atoms back to the beginning of step (c) (e) separating the saturated hydrocarbons from the reaction mixture in step (c) and forming a gas stream combining the saturated hydrocarbons from the reaction mixture in step (c) with the saturated hydrocarbons recycled from step (b) back to the beginning of step (a); (f) hydrogenating the higher olefins having 10 to 20 carbon atoms obtained according to step (c) to obtain diesel fuel and by-products selected from the group consisting of gasoline, liquefied petroleum gas and heating gas; and (g) separating the by-products formed according to step (f) from the diesel fuel.