Effectively Reduce Amine Foaming

Amine is a critical part of natural gas processing operations to effectively remove H2S (Hydrogen Sulfide) & C02 (Carbon Dioxide). There are various amine solvents on the market that are selective for the particular process and they all have one thing in common. Amines all will work more effectively when they are filtered to a quality effluent to prevent contaminant build-up in the system which can cause many mechanical and processing problems and amine foaming.

Operating a dirty amine system is never a good idea and the end result will be a day of reckoning with increased costs to the operator. Clean amines should be bright and clear indicating the system is in excellent shape. When particulates build up the amine becomes darker and can get to the point of a translucent black and by this time you will be in trouble with significant processing issues on the horizon.

One fairly common problem in gas processing operations is amine foaming. As fine solids build up, the surface tension of the amine changes and foam becomes stabilized contributing to reduced throughput for the plant and the possibility of amine losses with carryover and off-spec gas downstream of the contactor.

A common contaminant in an amine system are iron sulfide particulates and these can build up from a combination of factors and foremost among these is inadequate filtering. A minimum 10% of the amine should be filtered and this is usually done with two filters piped in in parallel so one filter can be serviced while the other is running to keep a constant filtering operation.

In addition to effective particulate filtration in the amine system, it is important to have an adequately sized charcoal filter in the loop to adsorb dissolved organics such as hydrocarbons that can also contaminate the amine and contribute to the foaming tendency.

It is also critical to note that only filtered amine should flow through the charcoal adsorber and the effluent from this system should be filtered to ensure the capture of any carbon fines that could possibly migrate downstream and can also contribute to foaming and other mechanical issues.

Some guidelines to help reduce amine foaming are to ensure your filter system is designed to meet the process flow rates and is effective to remove the particulates that can contaminate and build up in an amine system which can lead to a plethora of problems that multiply over time. If your filter system is undersized or uses filters that are not efficient to remove the particle size of contaminants in the 10 micron range, you may be unknowingly contributing to your amine foaming.

At PS Filter? we can evaluate your system and provide recommendations to reduce your processing costs to ensure you are getting the best bang from your filtration spending. Not all filters perform the same and it needs to be known upfront what the different options are so the best choices can be made to optimize processing operations. At the end of the day we feel it is of paramount importance that everyone is aware of ways to ensure their facilities can operate as safely and efficiently as possible without incurring excessive operational costs.

The reduction of amine foaming tendency will not only ensure the plant throughput is maintained, operational savings realized, and sales gas is on spec, there will also be considerable cost savings with the reduction of silicone based antifoam agents. These defoamers will temporarily stop foaming; too much however will make the problem worse.

There are a variety of factors that can cause foaming inside an amine scrubber:

• Corrosion Products
• Carbon Fines Migrating Downstream
• High Amine Concentrations
• Overloaded Amine
• Excessive Concentrations of Heat-Stable Salts
• Caustic in the Circulating Solution
• Presence of Heavy Aromatic Hydrocarbons

These factors can all act to reduce the surface tension of the amine which will increase the foaming tendency and associated problems as a result. Consistent effective filtration and reclaiming can alleviate most of these problems and ensure a smoother running amine system.