Removal of carbon dioxide (CO2), hydrogen sulfide (H2S), COS and RSH from synthesis gas, natural gas or other gases.
Products: Treated gas to meet pipeline, liquefied natural gas (LNG) plant, ammonia plant or petrochemical plant specifications. Acid offgas with very low inert gas content. Production of food-grade CO2 is possible.
Acid components, found in the feed gas, are removed by absorption with an aqueous solution of MDEA and an activator system. The rich solution leaving the absorber is regenerated by flashing and/or stripping through one or more regenerating steps. Different process configurations can be combined with various solvent types and concentrations to meet requirements for individual applications. It is possible to customize gas treatment to the customers’ economic priorities.
Operating conditions: Reference plants cover a range from 3,000 to 810,000 Nm3/hr feed gas capacity, absorber temperatures from 30°C to 90°C, absorber pressures from atmospheric range up to 120 bar and feed gas compositions from 0.5 to 25 vol.% CO2 and 0 to 15 vol.% H2S. Treatment at higher pressures with more CO2 /H2S in the feed gas is achievable.
Economics: The process is highly energy efficient due to the elevated acid-gas loadings achievable with the solvent; this enables using low circulation rates and reduced energy consumption, as well as reducing required equipment size. Energy consumption for CO2 removal from ammonia synthesis gas: 1 kWh/kmol CO2 electrical power and 32 MJ/kmol CO2 thermal energy. Thermal energy consumption for natural gas treatments: 15–20 MJ/kmol CO2 and H2S removed
(flash regeneration).
Additional advantages: very low hydrocarbon coabsorption, no degradation products, no corrosion (mainly carbon steel equipment can be used), low foaming tendency, no reclaimer operation is necessary, and the solvent is nontoxic and biodegradable.
Licensor: BASF AG
