Absorption system for separate recovery of carbon dioxide and hydrogen sulfide impurities

• US 3,910,777 A
• Filed: 12/18/1973
• Issued: 10/07/1975
• Est. Priority Date: 12/20/1972
• Status: Expired due to Term

• Current Assignee: Fritz Jakob
• Original Assignee: Fritz Jakob
• Inventors: Jakob, Fritz
• Primary Examiner(s): Hart, Charles N.
• Assistant Examiner(s): Spitzer, Robert H.
• Application Number:
  US05/425,862
• Time in Patent Office: 658 Days
• Field of Search: 55/48,51,53,68,73 62/9-12,17
• US Class Current: 95/161
• CPC Class Codes: C10K 1/165 at temperatures below zero degrees Celsius

Abstract

In a gas purification process comprising scrubbing out gaseous impurities comprising carbon dioxide and hydrogen sulfide from gases with an organic polar solvent scrubbing agent, said process being conducted under superatmospheric pressure, and at a low temperature, and expanding resultant loaded scrubbing agent to liberate a portion of the components dissolved therein, the improvement wherein after the expansion of the loaded solvent, the resultant expanded solvent is stripped with a stripping gas to remove the hydrogen sulfide and the resultant loaded stripping gas containing the hydrogen sulfide is scrubbed with hotregenerated scrubbing agent to remove the hydrogen sulfide therefrom.

Claims

1. IN A GAS PURIFICATION PROCESS COMPRISING IN A FIRST SCRUBBING COLUMN, SCRUBBING OUT GASEOUS IMPURITIES COMPRISING CARBON DIOXIDE AND HYDROGEN SULFIDE FROM GASES WITH AN ORGANIC POLAR SOLVENT SCRUBBING AGENT, SAID PROCESS BEING CONDUCTED UNDER SUPERATMOSPHERIC PRESSURE AND AT A LOW TEMPERATURE, AND EXPANDING RESULTANT LOADED SCRUBBING AGENT TO LIBERATE A PORTION OF THE COMPONENTS DISSOLVED THEREIN, THE IMPROVEMENT WHEREIN AFTER THE EXPANSION OF THE LOADED SOLVENT, THE RESULTANT EXPANDED SOLVENT IS STRIPPED WITH A H2SREMOVING STRIPPING GAS OBATINED FROM OUTSIDE THE PROCESS TO REMOVE THE HYDROGEN SULFIDE FROM SAID RESULTANT EXPANDED SOLVENT, RECYCLING THE STRIPPED-OUT SCRUBBING AGENT WITHOUT FURTHER REGENERATION TO SAID FIRST SCRUBBING COLUMN, SCRUGGING THE RESULTANT LOADED STRIPPING GAS CONTAINING THE HYDROGEN SULFIDE WITH THERMALLY COMPLETELY REGNERATED SCRUBBING AGENT IN A SECOND SCRUBBING COLUMN SEPARATE AND DISTINCT FROM SAID FIRST SCRUBBING COLUMN TO REMOVE THE HYDROGEN SULFIDE THEREFROM, AND THERMALLY AND COMPLETELY REGENERATING THE RESULTANT LEOADED SCRUBBING AGENT TO FROM SAID THERMALLY AND COMPLETELY REGENERATED SCRUBBING AGENT.

2. A process according to claim 1 wherein the hydrogen sulfide is scrubbed out of the stripping gas at a substantially lower temperature than the stripping of the hydrogen sulfide from the expanded solvents.

3. A process according to claim 1 wherein the loaded solvent, prior to expansion, is subdivided into a portion primarily loaded with CO2 and into a portion loaded with CO2 and H2S.

4. A process according to claim 3 wherein the portion of the solvent primarily loaded with CO2 is utilized for washing out H2S from an H2S-CO2 fraction.

5. A process according to claim 1 wherein CO2 is employed as the stripping gas.

6. A process according to claim 1 wherein CO2 and a foreign gas are utilized as the stripping gas.

7. A process according to claim 1 wherein, as the stripping gas, that gas is utilized from which the H2S has been scrubbed out with the hot-regenerated solvent.

8. A process according to claim 1 wherein the additional stripping gas is introduced while scrubbing out the H2S from the stripping gas.

9. A process according to claim 1 further comprising distilling resultant hot-regenerated solvent containing scrubbed out hydrogen sulfide to regenerate the solvent and recover the hydrogen sulfide as an overhead gas.

10. A process according to claim 1 wherein said stripping gas is nitrogen or methane.