The feed gas is introduced to the bottom of the absorber column where it contacts counter-currently with the lean amine which is fed to the top of the absorber column. The contacting device may be trays or packing type. The lean amine absorbs the acid gas components from the treated gas and this rich amine is then regenerated in the amine regeneration section with the acid gas releases. The rich amine solution flows from the bottom of the absorber to the flash drum where any absorbed / entrained hydrocarbons are separated either by flashing or by liquid/liquid gravity separation. Before going into the amine regenerator column, the rich amine stream is preheated in the lean/rich amine heat exchanger with hot lean amine as heating medium. In the amine regenerator column, trays or structured packing type, the rich amine solution is regenerated by stripping out the acid gas components at low pressure in the amine regenerator reboiler where the rich amine is heated by an electric/ fired gas or hot oil heater. The lean amine solution from the bottom of the amine regenerator column is cooled first in the lean/rich amine heat exchanger then in the lean amine cooler and pumped by the lean amine pumps to the top of the absorber column. Downstream of the lean amine cooler, a continuous slipstream is diverted out of the cooled lean amine solvent stream and is routed to a filter section that comprises of a particulate filter, an activated charcoal filter and a particulate guard filter in series to remove solid particles from the circulating stream.
The acid gas stream from the top of the amine regenerator column contains saturated water vapor and traces of solvent. The acid gas is cooled down in the condenser and flows to the reflux separator where the acid gas and sour water are separated. This sour water is recirculated into the regenerator. The acid gases are then discharged to the battery limit.
The unit is completed with interconnecting piping, valves, steelworks, instrumentation and control systems.
Depending upon the extension of the scope of supply, the acid gas removal section may be provided with additional inlet and outlet conditioning facilities (cooling, separation, filtration). Even the amine regeneration section may be provided with antifoam injection system, amine drainage system and amine make-up system.