Gas permeation is based on the mass transfer principles of gas diffusion through a permeable membrane. In its most basic form, a membrane separation system consists of a vessel divided by a single flat membrane into a high- and a low-pressure section. Feed entering the high-pressure side selectively loses the fast-permeating components to the low-pressure […]
Read More…Category: Gas Sweetening Processes
Distillation
The Ryan-Holmes distillation process uses cryogenic distillation to remove acid gases from a gas stream. This process is applied to remove CO2 for LPG separation or where it is desired to produce CO2 at high pressure for reservoir injection.
Read More…Sulfide Scavengers
Sour gas sweetening may also be carried out continuously in the flowline by continuous injection of H^S scavengers, such as amine-aldehyde condensates. Contact time between the scavenger and the sour gas is the most critical factor in the design of the scavenger treatment process. Contact times shorter than 30 sec can be accommodated with faster […]
Read More…Sulfa-Check
Sulfa-Check® process uses sodium nitrite (NaNO2) in aqueous solution to oxidize H2S to sulfur. This process was developed and patented by NL Treating Chemicals and is now a product of Exxon Energy Chemicals. It will generate NOX in presence of CO2 and O2. Therefore, local air quality emission standard should be consulted. This process is […]
Read More…IFP Process
The Institute Francais du Petrole has developed a process for reacting H2S with SO2 to produce water and sulfur. The overall reaction is 2H2S + 862 -» 2H2O + 3S. Figure 7-10 is a simplified diagram of the process. This process involves mixing the H2S and SO2 gases and then contacting them with a liquid […]
Read More…Stretford Process
An example of a process using O2 to oxidize H2S is the Stretford® process, which is licensed by the British Gas Corporation. In this process the gas stream is washed with an aqueous solution of sodium carbonate, sodium vanadate, and anthraquinone disulfonic acid. Figure 7-9 shows a simplified process diagram of the process. Oxidized solution […]
Read More…LOCAT Process
The LOCAT® process is a liquid phase oxidation process based on a dilute solution of a proprietary, organically chelated iron in water that converts the hydrogen sulfide to water and elemental sulfur. The process is not reactive to CO2. A small portion of the chelating agent degrades in some side reactions and is lost with […]
Read More…Claus Process
This process is used to treat gas streams containing high concentrations of H2S. The chemistry of the units involves partial oxidation of hydrogen sulfide to sulfur dioxide and the catalyticaily promoted reaction of H2S and SO2 to produce elemental sulfur. The reactions are staged and are as follows: Figure 7-7 shows a simplified process flow […]
Read More…Direct Conversion of H2S to Sulfur
The chemical and solvent processes previously discussed remove acid gases from the gas stream but result in a release of H2S and CO2 when the solvent is regenerated. The release of H2S to the atmosphere may be limited by environmental regulations. The acid gases could be routed to an incinerator or flare, which would convert […]
Read More…Rectisol Process
The German Lurgi Company and Linde A. G. developed the Rectisol® process to use methanol to sweeten natural gas. Due to the high vapor pressure of methanol this process is usually operated at temperatures of -30 to ~100°F. It has been applied to the purification of gas for LNG plants and in coal gasification plants, […]
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