MDEA foaming problem

I think we should identify the cause to find out what exactly is leading to foaming in the solution, and then take appropriate action. The reasons for foaming in the solution include: ① The amine solution contains corrosive by-products and solid impurities； ②Amine solution degradation products ； ③Hydrocarbons contained in amine liquids or gases ； ④The degassing of the feed gas is insufficient; the feed gas contains liquid hydrocarbons and produced water ； ⑤Various chemical agents, preservatives, and other active substances added upstream of the deacidification unit ； ⑥When the amine unit was put into operation, the system’s purification level was insufficient ； ⑦The quality of the water used for replenishment does not meet the requirements ； ⑧Deterioration in the performance of mechanical and activated carbon filters, etc. Almost all foreign substances and liquid-solid impurities can induce foaming in the solution; therefore, foaming of the solution inside the tower is an abnormal operating condition that is extremely difficult to predict. Solution foaming causes fluctuations in the device pressure drop, a significant reduction in processing capacity and acid removal efficiency, as well as a substantial increase in solvent consumption. Severe foaming will force the shutdown of the device. To prevent foaming of the solution, it is necessary to regularly measure its foaming tendency indoors, and to select the appropriate type and amount of antifoaming agent. When foaming occurs in the amine solution in the unit, an antifoaming agent is added as a contingency measure; the addition of this agent is stopped once the cause of the foaming has been identified and eliminated.

1. The tower diameter is too small, or the load is too high, or the foaming coefficient chosen in its design is too low. Solutions: a. Reduce the processing volume; b. Add antifoaming agents or lower the concentration of the amine solution; c. Increase the tower diameter at appropriate times. 2. The amine solution contains foaming substances. The absorption and regeneration of the amine solution are theoretically reversible processes, but in actual production various impurities are present, and certain components form TSS thermally stable salts with the amine solution, leading to foaming. A high concentration of the amine solution can also cause foaming. Solutions: a. Reduce the introduction of hydrocarbons and other impurities, and improve the maintenance of the filtration systems for the amine solution. b Add a Tss thermal-stable salt removal unit; c Reduce the concentration of the amine solution. The main cause of foaming in the amine solution is the presence of thermal-stable salts, and the best solution is to install additional equipment for purifying the amine solution in order to remove these salts. Furthermore, amine foam formation can also cause corrosion in the system, as well as issues such as amine entrainment and system blockage. Once foaming occurs in the amine solution, it is best to add as little antifoaming agent as possible, or not at all; otherwise, if chosen improperly, the antifoaming agent will instead exacerbate the foaming.

Add an appropriate amount of defoamer: victory:

Adding defoamers is a temporary solution; it is necessary to investigate the causes from various aspects such as the process, operational parameters, equipment performance, feed gas, and amine solutions, in order to identify the root cause. This is a process that takes time, and similar situations have occurred when our plant was put into operation as well – it is important to address the issues appropriately. .

There are many reasons for solution foaming. Adding an antifoaming agent should be used as a last resort, and it only has some effect when foaming first starts to occur; it is useless when foaming is already severe. First, it is necessary to analyze the cause of foaming – whether it is due to excessive fluctuations in gas volume, poor separation of the feed gas which results in solids and liquid hydrocarbons entering the absorption tower, or low temperature and high viscosity of the amine solution. Factors such as the rationality of the absorption tower’s design, whether the tower is clogged, and whether there are purification devices in the amine solution circulation system also need to be considered, in order to identify the root cause and take appropriate measures.

Bro, I suggest finding out the cause first; using an antifoaming agent isn’t a foolproof solution

1. Reduce the amount of feed gas. 2. Check the filter before the absorption tower. 3. Check the pressure difference in the absorption tower; too high a pressure difference can also cause foaming