Flexible process for converting carbon dioxide, hydrogen, and methane into synthesis gas

A process for converting feed streams selected from (1) a gas stream comprising carbon dioxide and a hydrogen rich gas stream;

• (2) a methane rich gas stream;
• and (3) a combination of feed streams (1) and (2) into a product stream comprising carbon monoxide, water and hydrogen, the process comprising:
• introducing the feed streams selected from (1), (2) or (3) and oxygen into a reaction vessel;
• in switching mode, performing method I or method II in the reaction vessel, wherein no catalyst is present, the reaction vessel being provided with a burner located at the top of the reaction vessel, the burner comprising coaxial channels for the separate introduction of the feed streams and the oxygen:
• in method I, performing a reverse water gas shift reaction at an elevated temperature, wherein (a) at least feed stream (1) and an oxygen rich gas stream are introduced into the reaction vessel via the burner in separate feed streams, wherein the hydrogen rich gas stream is introduced into the reaction vessel at a temperature between 15 and 500° C., (b) the hydrogen rich gas stream and the oxygen rich gas stream being introduced in close vicinity of each other, wherein the hydrogen and the oxygen in the hydrogen rich gas stream and the oxygen rich gas stream, respectively, undergo a combustion reaction upon entering the reaction vessel, thereby providing the heating energy required for the reverse water-gas shift reaction;
• and (c) the temperature in the reaction vessel is maintained in the range of 1000 to 1500° C. by varying the molar ratio of the hydrogen to the oxygen, which are introduced into the reaction vessel in the hydrogen rich gas stream and the oxygen rich gas stream, respectively;
• and
• in method II, performing a partial oxidation reaction at an elevated temperature, wherein (d) at least feed stream (2) and an oxygen rich gas stream are introduced into the reaction vessel via the burner in separate feed streams, (e) the feed stream (2) and the oxygen rich gas stream being introduced in close vicinity of each other, wherein the feed stream (2) and the oxygen rich gas stream undergo the partial oxidation reaction upon entering the reaction vessel;
• and (f) the temperature in the reaction vessel is maintained in the range of 1100 to 1500° C. by varying the flow rate of the oxygen and/or the feed stream (2);
• wherein during the switching mode from method I to method II or vice versa, the feed streams are gradually changed to the relevant feed streams, so that the feed stream (3) is present in an intermediate phase, the feed streams being introduced via the appropriate channels, while also changing the temperature of the reaction vessel to the desired temperature for the relevant method.