Foaming of industrial lean methyldiethanolamine solution in the presence of hydrocarbon and fatty acid based corrosion inhibitors

In natural gas sweetening alkanolamine processes, one of the regularly used chemical is the corrosion inhibitor. For better operation of the plant, it is essential to understand the effect of their presence on foaming of industrial lean methyldiethanolamine (MDEA) used as solvents at different temperatures. The effect of hydrocarbon based (HCB) and fatty acid based corrosion inhibitor having chemical bis(2-hydroxyethyl)cocoalkylamine (BHCL) on the foaming tendency of industrial real lean MDEA solutions was investigated. Experiments were conducted with different operating parameters, including liquid volume of the solution, foaming time, flow rate of nitrogen gas, concentration of the corrosion inhibitors, temperature of the solution, and gas diffuser pore size using the Foam Scan instrument. With the increase in solution volume and foaming time foaming happens to be more. The foaming tendency of lean MDEA solutions decreased wit hincreasing temperature in absence of corrosion inhibitors but showed different behavior in their presence. At small diffuser pore size and high gas flow rate, the final foam volume increased in the presence of HC Bbut decreased with the BHCL inhibitor. Optimizing the operating parameters to minimize foaming was verified to be a function of the type of inhibitor used.