The tail gas from natural gas purification industry can be treated by reduction absorption process. The principle of reduction and absorption process is to hydrogenation the tail gas, reduce the sulfur components in the tail gas to H2S, selectively absorb the generated H2S by amine method, and finally regenerate or lift out the gas, and then enter Claus unit for circulating reaction. The hydrogenation process has high investment and high operation cost. However, it can achieve quite high sulfur yield, such as more than 99.8%, which is widely used in countries and regions with high environmental protection requirements.
The reduction absorption method mainly includes the following processes:Scot process, HCR process, resulf process, bsrp process and RAR process.
Scot process the so-called Scot refers to the tail gas treatment technology of Claus sulfur plant of Dutch Shell. In general, the traditional Claus process (two-stage or three-stage) is used for sulfur recovery. The sulfur recovery rate of this process is about 95% ~ 97%. In today’s society, the requirements for environmental protection are higher and higher, and the allowable emission is less and less. If the sulfur recovery unit has large capacity, the recovery rate is very high (99% or higher). In this case, super Claus or Scot tail gas treatment system should be considered. However, if the recovery rate is required to reach more than 99.5%, scot can only be used.
HCR process the HCR process technology developed by Italian nigi company is also a kind of hydrogenation reduction absorption process. The main feature of this process is to use the delay of incinerator and the lung heat of process gas of sulfur making furnace to heat the tail gas, so there is no need for additional heating, so as to achieve the recycling of waste heat and greatly reduce the cost. Moreover, this process does not need additional hydrogen. The H2 decomposed by Claus section high temperature combustion furnace is enough to reduce the remaining sulfur into H2S.
Resulf process the resulf process developed by TPA company includes three types: resulf process, resulf-10 process and resulf mm process. Similar to Scot process, the tail gas of Claus unit is preheated first, and then mixed with reducing gas mixed with H2 to reduce the sulfur-containing component gas in the reactor to H2S. This process can be used to improve the sulfur recovery rate of the existing Claus unit.
Bsrp process is jointly developed by UOP and Parsons. Bsrp process is mainly used for tail gas treatment of Claus unit. This process has been widely used all over the world.
The total sulfur recovery rate of Claus / bsrp unit can reach more than 99.8%. Bsrp uses anthrone method to absorb H2S. The H2S content in the discharged tail gas is low, but there are many operation problems.
Rar technology KTI has developed a tail gas treatment process called rar (reduction, absorption and recycling). The process is based on reductive selective amines: the principle of the process is well known in the industry, which is almost the same as that of similar processes used in other similar applications. Rar process has reliable and efficient performance, and its sulfur recovery rate can reach 99.9%. It is the most efficient sulfur recovery process in the existing technology.
Post time: Jan-21-2022
