Econamine FG Plus is an energy efficient, patents pending process used to recover carbon dioxide (CO2) from low-pressure, oxygen (O2) containing streams, such as burner flue gas, combined cycle gas turbine flue gas and coal-fired power plant flue gas streams.
Flue gas is cooled in a direct contact cooler (1) and is sent to a blower to overcome pressure losses though the system. It then enters the absorber (2) bottom and flows upward through random dumped packing where the CO2 reacts chemically with the lean and semi-lean monoethanolamine (MEA) solvent to remove most of the CO2. MEA concentration is at least 30%.
Treated gas is passed through a water wash and vented through the top of the absorber. Solvent intercooling in the absorber may be utilized to reduce absorber size and solvent circulation rates.
The CO2-rich solution is split into two streams, heated and regenerated, utilizing two schemes: flash regeneration and steam stripping. Steam stripping takes place in the stripper (3) where energy is provided through the reboiler (5), producing a lean solution.
Flash regeneration is conducted in the semi-lean flash drum (4) where a semi-lean solution is produced without additional external energy. The overhead gas produced is sent to the stripper top. The gas is cooled and condensate is routed back to the column to generate CO2 product. This may be compressed for sequestration or liquefied to produce a saleable product. The lean and semi-lean solutions are pumped, cooled and filtered before being sent back to the absorber. The reclaimer (6) is operated intermittently to recover amine from heat stable salts and to remove degradation products.
Operating conditions: The feed gas may contain 3 to 25+ mol% CO2 and up to 15 mol% O2. The feed gas pressure may be near atmospheric. Due to the addition of an inhibitor that retards decomposition and corrosion, the majority of the plant may be constructed using carbon steel.
Economics: Typical US Gulf Coast investment (ISBL) for a 300 tpd plant is approximately $10.4 million. For a typical flue gas from a steam methane reformer, the energy consumption is approximately 1395 Btu/lb CO2. Solvent replacement costs approximately equal $2.09/ton CO2.
Licensor: Fluor Enterprises, Inc.
