In this post I want to share how to size amine system for natural gas sweetening, especially for MEA and DEA. For other amine systems, the licensee should be contacted for detailed design information. In the end of this post, I share simple spreadsheet on how to estimate amine circulation rate, minimum contactor diameter, and reboiler duty of amine system.
Amine absorbers provide intimate mixing between amine solution and sour gas. Typically, small diameter towers use stainless steel packing, while larger towers use stainless steel trays.
For preliminary design, a tray spacing of 24 in and a minimum diameter of capable of separating 150 to 200 micron droplets can be assumed. The size of packed towers must be obtained from vendor.
Commonly, amine absorbers are equipped with integral gas scrubber section in the bottom of the tower. The function of the scrubber is to remove entrained water and hydrocarbon liquids from the gas, therefore it protects amine solution from contamination.
Separate scrubber vessel can also be provided so that the tower height can be decreased. The vessel should be design using two-phase separators.
For MEA systems with large gas flow rate, a scrubber should be considered for the outlet sweet gas. It is because it will be helpful to reduce MEA losses in the overhead sweet gas. DEA systems do not require scrubber because vapor pressure of DEA is very low. Read More