Two-stage gas washing method
AssigneeNeste Oyj
InventorsJan Wahlström, Juhani Aittamaa, Isto Eilos
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Abstract
The present description is related to the field of hydrocarbon production by gasification of carbonaceous material. It provides a two-stage gas washing method as a part of gas refining. More specifically it discloses a method for hydrogen sulfide and carbon dioxide removal from synthesis gas produced by gasification. It introduces a use of a novel combination of wash approaches for this application. As a specific application, this process is utilized as a part of biomass to liquid (BTL) process.
Claims24
A method for washing hydrogen sulfide and carbon dioxide from a gas obtainable by gasification of carbonaceous biomass, said method comprising:
- a. contacting said gas with a first absorbent solution that is formed from only a transition metal ion-containing compound and water, said transition metal ion being selected from a group consisting of copper, zinc, iron, cobalt and mixtures thereof;
- b. binding hydrogen sulfide to said first absorbent solution;
- c. recovering the gas from step b;
- d. contacting recovered gas from step c with a second absorbent solution having an organic solvent, wherein the contacting of said recovered gas with the second absorbent solution takes place at a temperature in a range from −23 to 10° C., wherein the second absorbent solution having an organic solvent comprises methanol;
- e. binding carbon dioxide to said second absorbent solution;
- and
- f. recovering washed gas from step e.
Dependencies are inferred from the claim text.