Introduction With the development of our society, we advocate clean energy, so the demand for natural gas as a clean energy is also increasing. However, in the process of natural gas exploitation, many gas wells often contain hydrogen sulfide, which will cause corrosion of equipment and pipelines, pollute the environment and endanger human health. With the development of science and technology, The wide use of natural gas desulfurization technology has solved these problems, but at the same time, the cost of natural gas purification and treatment has increased accordingly. Principle Molecular sieve desulphurization (also called desulfurization) skid, also called molecular sieve sweeting skid, is a key device in natural gas purifying or natural gas conditioning project. Molecular sieve is an alkali metal aluminosilicate crystal with skeleton structure and uniform microporous structure. It is an adsorbent with excellent performance, high adsorption capacity and adsorption selectivity. Firstly, there are many channels with uniform pore size and neatly arranged holes in the molecular sieve structure, which not only provides a very large surface area, but also limits the entry of molecules larger than holes; Secondly, the surface of molecular sieve has high polarity due to the characteristics of ionic lattice, so it has high adsorption capacity for unsaturated molecules, polar molecules and polarizable molecules. Water and hydrogen sulfide are polar molecules, and the molecular diameter is smaller than the pore diameter of molecular sieve. When the raw gas containing trace water passes through the molecular sieve bed at room temperature, trace water and hydrogen sulfide are absorbed, Thus, the content of water and hydrogen sulfide in feed gas is reduced, and the purpose of dehydration and desulfurization is realized. The adsorption process of molecular sieve includes capillary condensation and physical adsorption caused by van der Waals force .According to Kelvin equation, capillary condensation decreases with the increase of temperature, while physical adsorption is an exothermic process, and its adsorption decreases with the increase of temperature and increases with the increase of pressure; Therefore, the adsorption process of molecular sieve is usually carried out at low temperature and high pressure, while the analytical regeneration is carried out at high temperature and reduced pressure. Under the action of high temperature, clean and low pressure regeneration gas, the molecular sieve adsorbent releases the adsorbate in the micropore into the regeneration gas flow until the amount of adsorbate in the adsorbent reaches a very low level. It also has the ability to adsorb water and hydrogen sulfide from the feed gas, realizing the regeneration and recycling process of the sieve. Technological process The process flow is shown in the diagram. The unit adopts three tower process, one tower for adsorption, one tower for regeneration and one tower for cooling.When the feed gas enters the unit, the temperature of the feed gas is reduced by the precooling unit, then the free water is removed by the coalescence separator, and then enters the molecular sieve desulfurization tower a-801, a-802 and a-803. The water and hydrogen sulfide in the feed gas are adsorbed by the molecular sieve to realize the dehydration and hydrogen sulfide adsorption process.The purified gas for dehydration and hydrogen sulfide removal enters the product gas dust filter to remove the molecular sieve dust and is exported as product gas. Molecular sieve needs regeneration after adsorbing a certain amount of water and hydrogen sulfide.Part of the product gas is led out from the product gas after dust filtration as regeneration gas. After the gas is heated to 270 ℃ in the heating furnace, the tower is gradually heated to 270 ℃ from top to bottom through the molecular sieve desulfurization tower that has completed the adsorption process, so that the water and hydrogen sulfide adsorbed on the molecular sieve can be resolved to become rich regeneration gas and complete the regeneration process. The rich regeneration gas after leaving the regeneration tower enters the regeneration gas condenser to be cooled to about 50 ℃, and the gas is cooled and supplied to the flare header. The molecular sieve tower needs to be cooled after regeneration. In order to fully recover and utilize heat energy, the regeneration gas is first used as cold blowing gas, and the tower is cooled to about 50 ℃ from top to bottom through the molecular sieve desulfurization tower that has completed the regeneration process. At the same time, it is preheated by itself. After the cold blowing gas exits the cooling tower, it enters the regeneration gas heating furnace for heating, and then regenerates the molecular sieve desulfurization tower as lean regeneration gas. The device switches every 8 hours.   Design Parameter Maximum handling capacity 2200 St.m3/h System operating pressure 3.5~5.0MPa.g System design pressure 6.3MPa.g Adsorption temperature        44.9℃