Abstract: Process for the removal of carbon dioxide (CO2) and minor sulfur compounds—mainly hydrogen sulfide (H2S)—from a sour gas mixture, such as natural gas, iron ore reduction gas, etc. The process uses a continuous absorption process with an alkaline aqueous liquid mixture containing 15-40% by weight of equivalent K2CO3 and is conducted at a temperature of about 150 degrees F. to 300 degrees F. The H2S is removed from the sour gas as elemental sulfur. A high concentration (at least 10 to 1 molar ratio) of penta-valent vanadium (V+5) to H2S is maintained at a high temperature (150 to 300 degrees F.) to help minimize thiosulfate formation, raise the absorption temperature, and increase the speed of conversion of H2S to elemental sulfur. CO2 is stripped from the aqueous alkaline solution and vented directly into the atmosphere since the sulfur that usually contaminates the CO2 was removed earlier in the process as elemental sulfur.

Abstract: An acid gas removal process employing a regenerator with an internal flash section is described. The regenerator uses gravitational flow to feed the flash section, eliminating the need for an external flash tank, and charge pump even without vacuum. The internal flash section has a first pressure side, a second pressure side having a lower pressure than the first pressure side during gas flow and a pressure reduction zone disposed therebetween. The pressure drop in the pressure reduction zone is due to liquid flow pressure losses occurring as liquid flows from said first pressure side to said second pressure side. A liquid seal between the first pressure and second pressure sides eliminates the need for a pressure let down valve. Vacuum control is provided by the first pressure side liquid level.

Abstract: A process and apparatus is disclosed for reclaiming of heat of reaction energy from an alkaline scrubbing solution used in acid gas removal processes and apparatus therefor. The heat recovered is used to produce steam which may then be employed to assist in steam stripping the rich scrubbing solution to effect regeneration thereof. The rich scrubbing solution containing heat of reaction thermal energy is passed through a rich-reflux reboiler to recover a part of the energy to produce at least a part of the stripping steam, and then through a rich-lean reboiler under a reduced pressure to produce additional quantities of stripping steam. A reduction in steam requirements for regeneration of the rich alkaline scrubbing agent of at least 10% is thereby realized.