The Fluor Solvent process is a physical solvent process to remove bulk carbon dioxide (CO2) and trace hydrogen sulfide (H2S) amounts from various gas streams. The process can remove CO2 to less than 1.0 mol% and H2S to 4 ppmv for natural gas. CO2 removal down to 1,000 ppmv is possible for synthesis gas. The process is particularly suited for feed gases with a CO2 partial pressure above 70 psia, H2S levels below 50 ppmv and <0.5 mol% C5+.
Feed gas is dried with TEG (1) and chilled (2, 3) to remove heavy hydrocarbons. Liquids formed are removed in a knock-out (KO) drum (4) and the gas enters the absorber (5). The gas is contacted with Fluor Solvent and propylene carbonate to remove acid gases. Acid gas desorption is accomplished without heat.
The rich liquid passes through three pressure flashes (6), an atmospheric flash (7) and a vacuum flash (8). The gas from the first three flash stages (6) containing significant volumes of hydrocarbons, is compressed (9) and recycled to the absorber. Hydraulic turbines between the absorber and the first stage flash and the first and second stage flashes recover energy and reduce refrigeration requirements. Patents are pending.
Since the solvent loading increases with decreasing temperature, the absorber is operated below 0°F to reduce the circulation rate. The solvent is non-hazardous, biodegradable and freezes at –57°F, making the process suitable for Arctic environments. It is usually the most economic choice for CO2 bulk removal when CO2 partial pressure is high and H2S concentration is low.
Process configurations for feed gas H2S concentrations up to 200 ppmv or for producing a liquid CO2 stream are also available.
Licensor: Fluor Enterprises, Inc.