Demanding Problems of Amine Treating of Natural Gas: Analysis and Ways of Solution

Selection Criteria for Antifoams Used in the Acid Gas Sweetening Process

“…Thus, the effectiveness of an antifoam depends on the chemical and physical factors as shown in Figure which describes the selection criteria of an antifoam in the acid gas sweetening process. Several characteristics that are used to determine the effectiveness of an antifoam includes having a high defoaming rate, demonstrating a highly persistent antifoaming action or ability, not contaminating or disrupting any process, and being nontoxic and stable at high temperatures …”

“…Therefore, a limited incompatibility is needed in order to have a balance between compatibility and agglomeration limit. The most common way is to measure the defoaming rate by measuring the reduction of foam level (foam tendency) and speed of removal of foam (foam stability) after the addition of an antifoam . The equations that can be used to feasibly measure the defoaming abilities are as shown in eqs and . , When the foam percentage reduction is high with a short foam break time, it indicates that the defoaming rate is high.…”

“…Several characteristics that are used to determine the effectiveness of an antifoam includes having a high defoaming rate, demonstrating a highly persistent antifoaming action or ability, not contaminating or disrupting any process, and being nontoxic and stable at high temperatures. 19 First, the solubility of an antifoam is of the utmost importance in the selection criteria. Here, the selected antifoam must be insoluble or partially soluble in the foaming medium to displace the foam by forming a bridge (as described in eq 5) which increases the speed of film thinning and breaks the foam bubble.…”

“…On the other hand, an antifoam is a chemical compound that is added before foaming occurs, hence preventing the solution from creating a stable foam . Although there are other conventional physical ways to reduce foaming which include continuous filtration, thermal treatment such as freezing and heating, electrical methods, mechanical foam breakers, and even using ultrasound, the addition of chemical antifoams is still preferred as compared to the other methods as stated. − This is because the use of antifoams in acid gas sweetening is considered to be the most effective and quickest way to reduce or eliminate the formation of foam. Typically, an antifoam is preadded into a foaming system as either as an oil, a hydrophobic solid compound, or a mixture of both compounds.…”

Perstraction of Heat-Stable Salts from Aqueous Alkanolamine Solutions

“…Chemical absorption using aqueous solutions of alkanolamines such as monoethanolamine (MEA), methyl diethanolamine (MDEA), and others is a mature technique for removing CO 2 and H 2 S from natural gas that demonstrates a high removal degree (>95%) of acid gases within a wide range of their partial pressures [4][5][6][7]. A key drawback of this technique is degradation (deactivation) of amine solvents [8,9] due to destruction of alkanolamines and their involvement in side chemical reactions. This is caused by high temperatures in acid gas desorption units (100-140°C) and, fairly often, by the presence of oxygen in the mixture (up to 10 vol % in flue gases).…”