What is the foaming phenomenon of the methyl diethanolamine solution used as a desulfurization agent, and what impact does foamed amine solution have on desulfurization?

Compared with traditional alcoholamine solvents, MDEA solutions have the drawback of being prone to foaming, which leads to a reduction in the efficiency of solution purification, inadequate solution regeneration, severe mist entrainment that results in increased solution loss, a significant decline in the system’s processing capacity, and gas output that does not meet quality standards. These issues not only affect the normal operation of the equipment but also cause serious economic losses; therefore, sufficient attention must be paid to this problem. Typically, the absorption tower is the part most prone to foaming, but the regeneration tower can also foam. Factors causing foaming in MDEA solutions: Bubbles are multiphase heterogeneous systems formed when a certain volume of gas is enclosed by a liquid; they have two main characteristics: bubble structure and stability. Although a clean MDEA solution has a tendency to form bubbles, these bubbles are extremely unstable and do not affect the normal operation of the equipment; it is only when foreign substances are present that the stability of the bubbles increases, causing the solution to foam. The main factors causing foaming in MDEA solutions are: 1. Solid particles, 2. Surfactants, 3. Amine degradation, 4. Large operational fluctuations. Prevention and treatment of foaming in MDEA solutions include: 1. Purifying the feed gas, 2. Improving solution filtration, 3. Preventing oxygen from entering the system, etc.

During foaming, the main manifestations are an increase in the differential pressure of the desulfurization tower, liquid carryover, and significant fluctuations in the liquid level of the desulfurization tower; these changes in the operation of the desulfurization tower can lead to a decline in its desulfurization efficiency

The main reasons for foam formation in amine solutions are as follows: first, the system is dirty with many mechanical impurities； Next is the presence of oil and hydrocarbons in the amine solution ； Another reason is the presence of thermally stable salts in the system, which is also the main cause. The consequences of amine solution foaming usually include, first, an impact on the desulfurization efficiency, and second, losses of amine solution.

Normal solvent foaming is mainly due to mechanical impurities, which increases side filtration. A defoamer can be added; foaming can lead to reduced effectiveness and solvent loss

The foaming phenomenon of amine solution refers to the change in its foaming properties due to contamination; this results in an increased foaming height and a longer time required to eliminate foam. Operationally, this can lead to an increase in the differential pressure in the desulfurization tower, as well as other issues. If your unit is used for desulfurization of coker gas, the main cause of \"foaming\" is the presence of a certain amount of coke powder in the dry gas. After desulfurization, this coke powder enters the amine solution and accumulates there, leading to contamination of the amine solution. Furthermore, the hydrocarbon condensates and liquid mist carried in the materials, along with the impurities generated by hydrogen sulfide corrosion of the equipment, can also cause the amine solution to \"foam\" when they accumulate to a certain level”

The phenomena include: ① Intense fluctuations in the liquid surface； ②Large pressure fluctuations inside the tower ； ③A large amount of foam can be seen inside the level gauge ； ④A large amount of foam was produced by the released solvent. The consequences of amine solution foaming are usually, first, a reduced desulfurization efficiency, and second, loss of amine solution. During the operation process, the amine solution will foam. To reduce this foaming phenomenon, the following measures can be taken: ① Install raw material filters for liquefied gas and dry gas that contain many impurities, in order to prevent the impurities in the raw materials from causing foaming. ②Control the temperature of the lean liquid entering the tower to be 5–6°C higher than the temperature of the gas entering the tower, in order to prevent the condensation of heavy hydrocarbons ； A water cooler can be installed in front of the dry gas tower, so that the cooled dry gas can have the condensed hydrocarbons separated from it before entering the absorption tower.

There are several reasons for foaming in amine solutions; one is too high a concentration, which increases viscosity. The solution is to dilute the amine solution； Second, the absorbed gas contains too many heavy components; the solution is to enhance the absorption of these heavy components by the gas at the front end ； Third, the amount of degradation products in the amine solution increases; the solution is to enhance the renewal of the amine solution. Reason: 1. The solution is too dirty and contains a large amount of suspended particles, such as iron sulfide, sand, salts, etc. 2. Excessively high amine solution concentration. 3. The feed contains a large amount of components with a carbon number of 5 or higher ； Components with a molecular weight of C5 or higher are dissolved in the amine solution, increasing its surface tension. 4. The amount of raw material suddenly increases, resulting in an increase in line speed. Treatment: 1. Strengthen the operation and management of the rich amine liquid filter. 2. Add condensate water to adjust the amine solution concentration properly. 3. Enhance oil removal in the flash tank to vaporize out as much of the amine solution dissolved in hydrocarbons as possible ； Contact the upstream unit to reduce the hydrocarbon content in the rich liquid. 4. Add an antifoaming agent.

The phenomena include: ① Intense fluctuations in the liquid surface； ②Large pressure fluctuations inside the tower ； ③A large amount of foam can be seen inside the level gauge ； ④A large amount of foam was produced by the released solvent. The consequences of amine solution foaming are usually, first, a reduced desulfurization efficiency, and second, loss of amine solution. During the operation process, the amine solution will foam. To reduce this foaming phenomenon, the following measures can be taken: ① Install raw material filters for liquefied gas and dry gas that contain many impurities, in order to prevent the impurities in the raw materials from causing foaming. ②Control the temperature of the lean liquid entering the tower to be 5–6°C higher than the temperature of the gas entering the tower, in order to prevent the condensation of heavy hydrocarbons ； A water cooler can be installed in front of the dry gas tower, so that the cooled dry gas can have the condensed hydrocarbons separated from it before entering the absorption tower.

Foaming of the amine solution will definitely affect its performance, and this in turn will impact the efficiency of desulfurization. In such cases, it is recommended that you use an antifoaming agent

It is best not to add antifoaming agents, as this could potentially cause more severe foaming.

The opinions expressed by the above-mentioned individuals are already very comprehensive. At present, the only and fundamental way to solve amine solution foaming is to carry out purification and revival. Removal of contaminants, including solid particles, thermally stable salts, etc. Under normal circumstances, do not add antifoam agents to it! ! !

It contains 21% oxygen, which is equivalent to the presence of hydrogen sulfide in air; the temperature ranges from 15 to 45 degrees. Can MDEA be used for desulfurization? I just saw a flue gas carbon dioxide recovery system in an oil refinery; it contained 10% oxygen, and the system was operating normally. Please ask an expert to explain whether oxygen actually has an oxidizing effect on MDEA Waiting online