Gas Sweetening Systems
Natural gas condensate, whether produced from a condensate field or an associated gas from an oil deposit, usually contains water and frequently contains Hydrogen Sulphide (H2S) and / or Carbon Dioxide (CO2). Gases containing H2S or CO2 are classified as sour, and gases free from H2S and CO2 are called sweet. With increasing demands to natural gas, natural gases containing H2S are also being tapped for utilization after purification. Natural gas that is transported to the fuel market must meet legal requirements, which specify a maximum H2S content less than 4 ppm in the gas. These requirements are justified, since H2S is a toxic gas, and its combustion product is sulfur dioxide or trioxide. Besides emitting a bad odor at low concentrations, H2S is deadly poisonous and at concentrations above 600 ppm it can be fatal in just three to five minutes. Its toxicity is comparable to cyanide. Thus, it cannot be tolerated in gas that would be used as domestic fuel. Further, H2S is corrosive to all metals normally associated with gas transporting, processing and handling systems, and may lead to premature failure of most such systems.
PTIL designs and manufactures efficient sweetening system capable of H2S removal. There are three distinct categories of removal systems designed and manufactured by PTIL. They are based on the following processes:
- Solid to Gas - These processes are applicable for removal of low concentration sulfur compounds in gas or liquid e.g. Iron-Oxide process. This type of system is most economical on process streams containing relatively large amounts of CO2 and less than 2000 PPM sulfur.
- Liquid to Liquid - These processes are used for treating gas liquids streams and are similar in design to the systems below used for treating gas streams e.g. Caustic wash, Merox process, Amine process, Molecular sieve process.
- Liquid to Gas - These processes have the greatest potential for treatment of sour gas streams. Once the H2S level exceeds 2000 PPM, this process is the only way to go. These processes utilize TEA, DEA, MEA, MDEA, Diglycolamine, Sulphinol, etc.