Modular Natural Gas Processing Plant | Rapid Deployment

Process Description

·MDEA Decarbonization Process Description:

   The feed gas is filtered through a separator and enters the bottom of the absorption tower, where it contacts lean MDEA solution sprayed from the top in a countercurrent flow. CO₂ and H₂S are selectively absorbed. The rich solution is depressurized in a flash tank to remove hydrocarbons, preheated in a lean rich solution heat exchanger, and then enters the top of the regeneration tower. Under steam stripping in the reboiler, CO₂ and H₂S are desorbed. The regenerated lean solution is exchanged, cooled, and pumped back to the absorption tower for circulation. The acid gas from the top of the tower can be sent to sulfur recovery or CO₂ liquefaction units.

·Molecular Sieve Dehydration Process Description:

   After decarbonization, the raw gas enters adsorption Tower A, where water is selectively adsorbed by the molecular sieve bed. The outlet dry gas has a water dew point ≤ -60°C and is sent downstream. After adsorption saturation, Tower B switches to the regeneration process: dry gas or nitrogen is heated in a heater and used for reverse purging of the molecular sieve bed. The desorbed water is condensed and separated in a cooler. Subsequently, cold dry gas is used for forward cooling of the bed to 40°C, completing regeneration for standby. The dual towers automatically switch via programmed valves, with a cycle time of 8–12 hours.

·Low-Temperature + Temperature Swing Adsorption (TSA) Process Description:

   After molecular sieve dehydration, the raw gas enters a plate-fin heat exchanger for precooling, causing partial condensation of C₅+ heavy hydrocarbons. It is then deeply cooled by a turbo-expander or mixed refrigerant, and oil phase (recovering LPG/NGL) is separated in a low-temperature separator. Residual heavy hydrocarbons in the gas phase enter the TSA molecular sieve adsorption tower, where heavy hydrocarbons are selectively adsorbed. The outlet gas, with heavy hydrocarbon content ≤ 20 mg/Nm³, is sent to the liquefaction unit. After adsorption saturation, heated purified gas is used for reverse purging regeneration. The desorbed heavy hydrocarbons are cooled and recovered, and the regeneration gas is used as fuel gas.