AbstractA 65wt% DGA?R solution was selected as a CO2 removal solvent in a gas processing plant in a sweet gas field onshore Japan. However very severe operational problems such as corrosion of AISI 304 stainless steel foaming and fouling occurred in the DGA units. In case of foaming a foam depressant was to be added for more than 50 times a day. And the added silicone type foam depressant decomposed and polymerized in the high temperature alkaline DGA solutions and resulted in the severe fouling. This fouling made to get the foaming worse. There should be a vicious circle between the foaming and the fouling in the DGA units.The root cause of the foaming was considered to be the stabilization of foams by the corrosion products due to the severe corrosion of 304 stainless steel. So a new project was initiated to develop a foam depressant having corrosion inhibitive properties.A silicone type foam depressant having very high stability in the particular DGA units was selected and hydrophobic silica was added. Some trial products were evaluated from the viewpoint of corrosion inhibitive characteristics in addition to foam controlling and minimal tarring properties.The selected new foam depressant controlled the number of foaming to less than 10 times a day and the severity of fouling as well. In addition to these the new foam depressant controlled the development of corrosion of 304 stainless steel clad in the upper half of the regenerator in the DGA units. As a result stable operations of the unit became possible and the safety and economic efficiency of the units were improved.