Acid Gas Removal
Amines & Acid Gas Removal
Acid gas removal eliminates acid gases from hydrocarbon streams such as natural gas, natural gas liquids (NGLs), and hydrogen streams. Typically, acid gas refers to hydrogen sulfide and carbon dioxide, but an acid gas is any similar contaminant that must be removed from a hydrocarbon stream (mercaptans, carbonyl sulfide, carbon disulfide, carbon monoxide, etc). Acid gas must be removed prevent corrosion, improve process efficiency, prevent hydrate formation, and ensure the product meets pipeline and sales specifications.
Amine plants remove acid gases (CO2; H2S) from hydrocarbons if properly designed, operated, and maintained. In these amine plants, acid gases are removed from hydrocarbons by contacting the gas stream with an aqueous amine solution in an absorber, where the amine chemically binds the acid gases. The rich amine is then regenerated by heating in a stripper, releasing the acid gases and recycling the lean amine back to the absorber.
Coastal Chemical delivers various amine solutions with the technical expertise to keep your acid gas removal units performing at peak efficiency.
Formulated amines and solvents are proprietary blends designed to optimize acid gas removal performance, often combining chemical solvents like MDEA with physical solvents or activators. Unlike generic amines such as MEA or DEA, which are single-component and standardized, formulated products are tailored for specific outcomes like selective H₂S removal or reduced regeneration energy. These blends can improve efficiency, reduce corrosion, and meet tighter environmental or product specifications. Their composition and behavior are typically proprietary and vary by manufacturer.
The GAS/SPEC Technology Group offers a family of specialty amines based in MDEA technology to remove acid gas from process streams.
Coastal offers the following GAS/SPEC products for H2S and CO2 removal:
- GAS/SPEC CS – 1160 Maximum CO2 removal
- GAS/SPEC CS – 1 Bulk CO2 Removal
- GAS/SPEC CS – 2000 Bulk CO2 Removal
- GAS/SPEC CS – Plus Maximum CO2 Removal
- GAS/SPEC TG-10 Extreme Deep H2S Removal
- GAS/SPEC TRS-2 & TRS-2b Refinery Heat Stable Salt Management
- GAS/SPEC SS Solvent H2S Removal
- GAS/SPEC CS-1000 Bulk CO2 Removal
- GAS/SPEC CS-3 Moderate CO2 Removal
- GAS/SPEC SS-3 Deep H2S Removal
- GAS/SPEC SG-1060 CO2 Removal
Coastal AGR II Solvent has been used since 1965 to remove carbon dioxide, hydrogen sulfide, mercaptans, and other sulfur-containing gases from natural gas, synthesis gas, ammonia streams, landfill gas, and Claus feed gas.
Coastal AGR II Solvent is also known as DMEPG, or Dimethyl Ether Polyethylene Glycol.
Sulfinol from Shell uses amines and sulfolane to treat sour gases that contain sulphur in the form of mercaptans. The advantages of using Sulfinol are the one-step removal of acid gases and trace organic sulfur, faster CO2 and COS removal, higher loading capacity, and reduced solvent degradation.
The offered variations of Sulfinol include:
- Sulfinol D
- Sulfinol M
- Sulfinol X
Coastal Chemical provides generic amines including MEA and DEA.
Aqueous monoethanolamine (MEA), diethanolamine (DEA), diglycolamine (DGA), diisopropanolamine (DIPA) and methyldiethanolamine (MDEA) are widely used industrially for hydrogen sulfide (H2S) and carbon dioxide (CO2) removal from natural gas and refinery process streams.
MEA (a primary amine) is good for low-pressure applications in acid gas removal with stringent treated gas specifications. MEA is commonly used for deep to complete CO2, H2S and COS removal.
Due to possible corrosion concerns, MEA is operated in low-concentration solutions. Most units using MEA require a side high-temperature reclaimer to manage heat-stable salt formations.
DEA (a secondary amine) is a good general-purpose ethanolamine and in general, is the most common generic amine used in acid gas removal from natural gas and NGL. It is used in higher concentrations (20-30wt%) than MEA (<15wt%) for acid gas removal and other organic acids.
Methyldiethanolamine, also known as N-methyl diethanolamine and more commonly as MDEA, is widely used as a sweetening agent in chemical plants, oil refineries, syngas, and natural gas production. MDEA is less corrosive and has lower energy requirements for acid gas removal applications.
MDEA is an excellent solution for selectivity between H2S and CO2 removal, and it can be used in higher concentrations (up to 55wt%).
Di-isopropanolamine (DIPA) is a secondary amine with some selectivity for H2S.
Coastal Chemical offerings include DIPA 85% and DIPA 90%.
Also referred to as Diglycolamine, ADEG® is a primary amine used for total H2S and/or CO2 removal at low partial pressures.
It works well at low pressures but requires the highest regeneration energy and has the highest corrosion risks out of all the alkanolamines. ADEG® is also known as aminoethoxyethanol (AEE). Thermal reclamation is feasible with ADEG®.
The addition of caustic to a solution of amine heat stable salts frees up the total concentration of amine for service in acid gas removal capacity, reduces the corrosivity of the circulating solution, extends the solvent run time between solvent reclamation to remove total heat stable salts and increases the viscosity of the circulating solution.
Coastal TRS Additive is a proprietary blend of amine and alkaline base materials used to neutralize anions and other heat-stable salts in amine solvents. TRS works effectively in any amine solution and can be used to neutralize bicine, acetate, formate, glycolate, oxalate, sulfate, thiocyanate and thiosulfate
Benefits
Amine unit operational savings occur as a result of the following AminePro 807® benefits.
- Prevention of exchanger or tray fouling due to deposition of iron sulfide, iron carbonate, or hydrocarbon sludge.
- Minimizes filtration expense by inhibiting the formation of additional iron sulfide or iron carbonate after initial passivation.
- Protects all piping and equipment from corrosion by forming a hard impervious layer of passivation on the metal surface.
- Maintains clean metal surfaces and will slowly remove debris from fouled surfaces.
- Minimizes the formation of hydrocarbon sludge in amine units by preventing polymerization.
- Consumes oxygen to minimize solvent degradation to heat stable salts.
The result is a cleaner amine system with less foaming, fouling or corrosion and the capability to operate at higher amine concentrations, increasing amine unit capacity.
Continuous Injection
AminePro 807® is injected continuously to either the rich or the lean amine. To ensure optimum protection, the addition rate is adjusted based on the residual levels in the amine solution based on Coastal’s laboratory analyses as part of the program.
Coastal Chemical’s H2S scavenging program follows a 4-stage process:
1. System Evaluation
Results of this evaluation allows for identification of the most efficient product at the most effective location, as far upstream as possible.
2. Product Selections
Product Selection takes into account the data that was gathered from the system evaluation to ensure the correct product is chosen for the correct application.
3. Dosage Rate or Usage Calculations
Dosage Rate or Usage Calculations are figured using the stoichiometry of the chemistry being utilized, along with field established usage factors.
4. Efficiency Monitoring
Efficiency Monitoring is conducted on each injection location, at a specific time interval, to ensure the effectiveness and efficiency of the H2S treatment program.
Contact us to learn how we can assist in acid gas removal processes.
800.535.6182
Coastal Chemical