Filtration Applications in Amine Desulfurization

The amine desulfurization Method is widely used in Refinery dry gas and LPG processing. H2S and CO2 from the gas are absorbed by the amine solution, forming an alcohol amine salt’s solution. H2S & CO2 can then be stripped from the gas through a heating process, allowing the amine to be re-generated for recycle use. 

During the process of amine desulfurization, besides absorbing H2S and CO2, the amine solution may also react with other materials or carry solid particles from the pipe. These include heat-stable salts, sulfide, iron dust, etc. This may cause foaming & fouling, lower the absorption efficiency, or even damage the equipment. 

Due to the problems in the process as mentioned above, amine filtration becomes an important process accompanied with gas desulfurization. Feature-tec has provided optimized solutions for amine desulfurization for years.

Problems in the Process: 

• Amine foaming in contactor tower and stripper column, due to reaction between high concentration of hydrocarbons and organic acids, cause loss of amine solvent, poisoning of catalyst and lowering contact efficiency.

• Liquid hydrocarbons from the natural gas, FeS/SS , chemical treatment agents cause fouling in the cooling tower and heat exchangers, thus lowering the efficiency, corroding the heat exchange meter and damaging the heat equipment. 

• Frequent Amine top ups cause increased maintenance costs. The formation of heat stable salts and cyanide cause fouling of the carbon bed, which in turn causes an increase in the consumption of energy. This also causes an increase in the use of anti-foaming agents which increases the amount of waste produced.

Causes for Foaming

• Foaming of the amine is caused by hydrocarbons and organic acids.

• Treated fluid and anti-corrosion agent 

• Oil, inhibitors and welding fluid 

• Water contaminants     

• Suspended solids (indirectly causes amine foaming) 

     - FeS, Carbon powder, iron oxides

     - Inefficient filtration and separation of inlet flue gas

• Cotton String Wound Filter Cartridge 

     - Unsatisfactory filter material

Suspended Solid Causes:

• Rust, iron sulfide from sour gas pipeline due to corrosion 

• Mineral deposits, Rust and pipe scale from water 

• Iron sulfide, rust, pipe scale and activated carbon  from activated carbon bed filter

Keys to Maintaining a Clean System

• Limit flow rate of lean amine and natural gas to reduce the carbohydrate concentration. 

• Fully filtrate the incoming sour gas to reduce contaminants such as liquid hydrocarbons, FeS / SS solid particles and water. 

• Ensure sufficient pre-filter and after-filter for activated carbon bed 

• Select an appropriate mechanical filter material 

• Use anti-foaming agent temporarily

Filtration Solution of Amine Desulfurization

Coalescer	Polypropylene FSH Filter Cartridge	SelfClear®

1. Sour Gas filtration : prior to processing the amine cleaning , the solid and liquid impurities present in the sour gas should be removed. Feature-Tec’s Coalescer filter will be able to filter off and intercept the solid and liquid impurities such as Iron sulfide, rust, etc efficiently. 

2. Amine recovery: A coalescer can be installed to recover the amine carried over by the gas, to reduce the loss of amine and cut the maintenance costs.

3. Amine foaming prevention: The Polypropylene FSH Filter Cartridge which provides high dirt holding capacity be applied to the rich amine and lean amine solution filtration, removing the solid particles, and run through the activated carbon filter to remove the gas in the amine solution. This helps to prevent amine foaming, thus protecting the downstream equipment. 

4. Feature-Tec’s SelfClear is the best solution to deal with rich amine filtration to remove small and deformed particles. 

Feature-Tec Amine Desulfurization Application References

Before and After Filtration 　　Customer: China National 　　Offshore Oil Corporation (CNOOC) 　　Filtration application: 　　Amine Filtration 　　Design Features: 　　SelfClear Filter System

Advantages and Special Features of SelfClear Filter System