Embodiments of the disclosure provide a method and system for sulfur recovery. A Claus tail gas stream is fed to a hydrogenation reactor to produce a hydrogenated gas stream. The hydrogenated gas stream is fed to a quench tower to produce a quenched gas stream. The quenched gas stream is fed to a first stage adsorption vessel of first stage adsorption unit to produce a first outlet gas stream. The first outlet gas stream is fed to a second stage adsorption vessel of a second stage adsorption unit to produce a second byproduct gas stream. The first stage adsorption vessel is regenerated to produce a first byproduct gas stream. The second stage adsorption vessel is regenerated to produce a second outlet gas stream including hydrogen sulfide. Optionally, a portion of the second byproduct gas stream or nitrogen can be fed to the first stage adsorption vessel or the second stage adsorption vessel for regeneration. Optionally, a sales gas can be fed to the second stage adsorption vessel for regeneration. Optionally, vacuum can be applied to the first stage adsorption vessel or the second stage adsorption vessel for regeneration.

Embodiments of the disclosure provide a method and system for sulfur recovery. A Claus tail gas stream is fed to a hydrogenation reactor to produce a hydrogenated gas stream. The hydrogenated gas stream is fed to a quench tower to produce a quenched gas stream. The quenched gas stream is fed to a first stage adsorption vessel of first stage adsorption unit to produce a first outlet gas stream. The first outlet gas stream is fed to a second stage adsorption vessel of a second stage adsorption unit to produce a second byproduct gas stream. The first stage adsorption vessel is regenerated to produce a first byproduct gas stream. The second stage adsorption vessel is regenerated to produce a second outlet gas stream including hydrogen sulfide. Optionally, a portion of the second byproduct gas stream or nitrogen can be fed to the first stage adsorption vessel or the second stage adsorption vessel for regeneration. Optionally, a sales gas can be fed to the second stage adsorption vessel for regeneration. Optionally, vacuum can be applied to the first stage adsorption vessel or the second stage adsorption vessel for regeneration.

A multi-stage process to remove contaminant gases from raw methane streams is provided. The present technology is an innovative solution to recover and purify biogas by use of a process having at least two pressure swing adsorption stages. Taking advantage of the presence of carbon dioxide in the raw biogas streams, nitrogen and oxygen are bulky removed in the first stage, using selective adsorbents, and a nitrogen and oxygen-depleted intermediate stream is yielded to the second stage. The second stage employs an adsorbent or adsorbents to selectively remove carbon dioxide and trace amounts of remaining nitrogen and oxygen, thus producing a purer methane stream that meets pipeline and natural gas specifications.

A multi-stage process to remove contaminant gases from raw methane streams is provided. The present technology is an innovative solution to recover and purify biogas by use of a process having at least two pressure swing adsorption stages. Taking advantage of the presence of carbon dioxide in the raw biogas streams, nitrogen and oxygen are bulky removed in the first stage, using selective adsorbents, and a nitrogen and oxygen-depleted intermediate stream is yielded to the second stage. The second stage employs an adsorbent or adsorbents to selectively remove carbon dioxide and trace amounts of remaining nitrogen and oxygen, thus producing a purer methane stream that meets pipeline and natural gas specifications.

Apparatus and methods for treating acid gas, which utilizes multi-stage absorption cycle of ammonia desulfurization to treat acid tail gas after pre-treatment of the acid gas, thereby achieving the purpose of efficient and low-cost treatment of acid tail gas. The parameters of the acid tail gas may be adjusted by a regulatory system such that the enthalpy value of the acid tail gas is in the range of 60-850 kJ/kg dry gas, for example, 80-680 kJ/kg dry gas or 100-450 kJ/kg dry gas, to meet the requirements of ammonia desulfurization, and achieve the synergy between the acid gas pre-treatment and ammonia desulfurization. Furthermore, hydrogen sulfide may be converted into sulfur/sulfuric acid plus ammonium sulfate at an adjustable ratio.

Apparatus and methods for treating acid gas, which utilizes multi-stage absorption cycle of ammonia desulfurization to treat acid tail gas after pre-treatment of the acid gas, thereby achieving the purpose of efficient and low-cost treatment of acid tail gas. The parameters of the acid tail gas may be adjusted by a regulatory system such that the enthalpy value of the acid tail gas is in the range of 60-850 kJ/kg dry gas, for example, 80-680 kJ/kg dry gas or 100-450 kJ/kg dry gas, to meet the requirements of ammonia desulfurization, and achieve the synergy between the acid gas pre-treatment and ammonia desulfurization. Furthermore, hydrogen sulfide may be converted into sulfur/sulfuric acid plus ammonium sulfate at an adjustable ratio.

An inerting system includes a fluid circuit, a reactor within the fluid circuit, at least one particulate removal device (PRD) downstream from the reactor, and a fluid tank. The fluid tank is downstream from the at least one PRD. A method for removing particulates from a fluid stream in a fluid circuit includes receiving a fluid stream in a reactor within a fluid circuit, outputting an exhaust stream from the reactor, receiving the exhaust stream in at least one PRD downstream from the reactor, removing particulate from the exhaust stream, and receiving the exhaust stream with particulate removed in a fluid tank downstream from the at least one PRD.

An inerting system includes a fluid circuit, a reactor within the fluid circuit, at least one particulate removal device (PRD) downstream from the reactor, and a fluid tank. The fluid tank is downstream from the at least one PRD. A method for removing particulates from a fluid stream in a fluid circuit includes receiving a fluid stream in a reactor within a fluid circuit, outputting an exhaust stream from the reactor, receiving the exhaust stream in at least one PRD downstream from the reactor, removing particulate from the exhaust stream, and receiving the exhaust stream with particulate removed in a fluid tank downstream from the at least one PRD.

A flue gas can be cooled for carbon capture purposes with the use of a gas-to-gas exchanger, using air as the cooling media, downstream of a heat recovery process, and optionally upstream of a quenching process; the use of an amine chilling process to reduce the required flue gas cooling duties upstream of the CO.sub.2 absorber; the use of a gas-to-gas exchanger, using the absorber overhead as the cooling media, downstream of a heat recovery process, and optionally upstream of the quenching process; and/or the use of a quenching process in which heated water and condensate is cooled by an external cooling loop utilizing treated flue gas condensate in an evaporative cooling process.

A method and apparatus for purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system can include passing air through a first adsorber of the PPU to purify the air for operation of the ASU system while it is at or below a first pre-selected operational capacity. In response to the operational capacity of the ASU system needing to be increased to a level above the first pre-selected operational capacity threshold, a second adsorber can be brought on-line in parallel with the first adsorber or in series with the first adsorber to provide improved purification capacity to account for the increased demand for purification capacity resulting from the increased operational capacity of the ASU system. This second adsorber can be different from the first adsorber (e.g. different in size, adsorption capacity for impurities within air, and/or configuration, etc.).