As a clean, convenient and high-energy fuel, natural gas is also an important chemical raw material, which plays an increasingly important role in people's daily life and factory production. Since the 1960s, with the rapid development of national economy and the substantial growth of energy demand, China's natural gas industry has developed rapidly. Natural gas is divided into sour natural gas and non sour natural gas. Sour natural gas must be purified before it can be sold as commercial natural gas.
Sour natural gas is called "crude natural gas". Its treatment process includes desulfurization and decarbonization, sulfur recovery and tail gas treatment. Desulfurization and decarbonization is to obtain clean natural gas. Sulfur recovery and tail gas treatment can transform toxic and harmful substances into by-product sulfur, meet the requirements of environmental protection, and truly realize "turning waste into treasure".
After more than 50 years of continuous research, southwest oil and gas field has developed a series of technologies for different gas quality conditions and treatment requirements. According to different sulfur content, three kinds of gas quality are classified as "high, medium and low". Technologies of desulfurization and decarbonization by alcohol amine method, liquid phase oxidation-reduction desulfurization, solid desulfurization and biological desulfurization are developed, and supporting technologies of natural gas desulfurization and decarbonization are improved. After desulfurization and decarbonization treatment, natural gas containing hydrogen sulfide and other impurities also needs dehydration treatment. After meeting the national standards, it officially becomes commercial natural gas and enters the pipeline network for supply.
The gas containing hydrogen sulfide is enriched by desulfurization and decarbonization, which is called "acid gas". Most acid gas enters sulfur recovery and tail gas treatment unit for recovery, which will turn into sulfur products. Sulfur recovery technologies in southwest oil and gas field development include conventional Claus technology, organic sulfur hydrolysis technology, H2S selective oxidation technology and conventional / low temperature hydrohydrolysis technology, etc, Hydrogen sulfide in "sour gas" is converted into sulfur compounds not converted by sulfur through classical Claus reaction (hydrogen sulfide reacts with SO2 to generate elemental sulfur) and hydrolysis reaction of organic sulfur, and then enters into tail gas treatment link for burning, so as to achieve standard emission.