An Experimental and Theoretical Analysis of Foam Formation in the Sour Gas Sweetening Process

Use of amine solutions for the removal of acid gases such as carbon dioxide (CO2) and hydrogen sulfide (H2S) from natural gas is the most common method, and, in this process, operational problems because of foaming are reported. Foaming can lead to the entrainment of liquid into downstream process equipment and might result in a situation in which the process specifications cannot be met for acid gases. Alkanolamines in general have a negative effect on downstream process equipment, and the loss of amines has a negative effect on the health, safety, and environment (HSE). The foam reducing agents are often used to reduce the risk of heavy foaming in amine plants. This study concerns with foaming in amine-based CO2 plants. To investigate foaming related to CO2 removal from natural gas by amine solutions, the fundamental theory of foaming in gas-liquid contactors was first reviewed. Then, experimental techniques related to this phenomenon in diethanolamine (DEA)/CO2 absorbers were considered. After that, foaming of diethanolamine solution polluted with different impurities was noticed, and the tendency of foam was measured by considering their foaming indices. To analyze the experimental measurements and experimental observations, a mathematical model was developed too. The model could justify the experimental measurement reasonably.