Foaming behaviour of an aqueous solution of n-methyldiethanolamine (mdea) and aqueous solution of piperazine (pz)-n-methyldiethanolamine (mdea) for the carbon dioxide removal

摘要

This work focuses on one of the severe problem arise by the usage of amine in the removal of acid gases namely carbon dioxide (CO2) which is foaming. Foaming can cause reduction integrity of plant operation, excessive loss of absorption solvents, premature flooding, reduction in plant throughput, off-specification of products and high absorption solvent carryover to downstream plants. Foaming tendency can be experimentally evaluated by variation of parameters, such as temperature, concentrations and type of impurities (sodium chloride, acetic acid, iron sulphide). Prior to each experiment, aqueous solutions of MDEA of different concentration are prepared by volume (for concentration parameter), the prepared solutions are heated in a temperature bath to a set temperature (for temperature parameter) and different impurities are added into the solution (for impurities parameter). Effect of all this parameters will be evaluated based on height of foam in millilitre (ml) and collapse time of foaming in seconds (s). Nitrogen gas (N2) will be use in this experiment as bubble gas. Results reveal that increase the pure MDEA concentration will decrease the foaminess. Similarly results also indicated that by increase the solution temperature will decrease the foam formation. For the investigation of foaming on temperature parameter, MDEA-Pz solution show greater to contribute on foaminess than pure MDEA solution at same amount of MDEA used. At the same amount of the impurities, iron sulphide appeared as the most influential contaminant to the foam formation, which promoted the highest foamability in any concentrations of piperazine-MDEA solution