Application of amine desulfurization filtration
Amine liquid desulfurization is mostly used in refinery dry gas and liquefied gas desulfurization. Amine liquid is used to absorb H2S and CO2 in the gas to achieve purification purpose. The solvent converted into alkanolamine salt releases H2S and CO2 after heating and stripping, and the amine liquid is recycled after regeneration.
In the process of amine desulfurization, in addition to the absorption of H2S and CO2, it often reacts with other substances in the system or entrains solid impurities into the upstream pipeline, including thermally stabilized salts, sulfides, iron filings, etc. It is easy to cause foaming, scaling and other problems, resulting in reduced efficiency and serious consequences of equipment damage.
Therefore, amine filtration is particularly important in gas desulfurization. Combined with practical application experience, the optimized solution for amine liquid desulfurization process was proposed, and many problems in production line were solved.
The main problems facing refineries are as follows:
If the concentration of hydrocarbon in the solution is too high, it will form amine foaming with organic acid, which will cause foaming in contact tower and stripping tower, cause solvent loss, sulfur regeneration catalyst poisoning, and reduce contact rate.
The liquid hydrocarbons, FES / SS and chemical treatment agents in the raw natural gas cause scaling of the condensing tower and heat exchanger, reducing the efficiency and strongly corroding the heat exchanger, resulting in thermal equipment damage.
The frequent replacement of amine filtration, the generation of thermal stable salt, the generation of cyanide, the scaling of filter medium activated carbon, the increase of heat energy use, the supplement of solvent, the increase of treatment wastewater and so on cause the maintenance cost to increase continuously.
Causes of blistering
▶ Hydrocarbon and organic acids cause amine foaming
▶ Treated fluid and corrosion inhibitor
▶ Oil, inhibitor and welding fluid
▶ Water pollutants
▶ Suspended solids (which do not actually cause blistering but can stabilize)
Ferrous sulfide, FES, fine carbon powder, colloidal iron oxide
Poor separation of inflow natural gas and insufficient filtration of solution
▶ Natural cotton filter
Improper selection of filter materials
Keeping a clean system is the key
▶ Reducing the concentration of carbohydrates by controlling the flow of lean amine water and natural gas
▶ Fully filter natural gas to reduce liquid hydrocarbon, FES / SS, chemical treatment agent
▶ Sufficient activated carbon and mechanical filtration
▶ Proper selection of mechanical filter materials
▶ Temporary use of antifoaming agents