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Tannin extract desulfurization technology is widely applied in China, however, in which there are sulfur-containing byproducts that can cause negative effects, such as reducing desulfurization efficiency and increasing operating cost etc. Thus, inhibiting side reactions and controlling byproducts is an important problem to be resolved. In this article, the cause of byproducts formation by thermodynamic analysis is reported. First, the reaction mechanism between HS−and pentavalent vanadium V(V) in desulfurization solution is researched, and it is conclude that HS−can transforms instantly into polysulfide ionsSx2−, thenSx2−forms the element sulfur. Thus,Sx2−is the main source to generate byproducts. Second, by calculating and comparing the Gibbs free energy change of side reactions, the results show thatSx2−is more active than HS−in solution and can react more easily with oxygen to produce byproducts. Therefore, quickening the transformation fromSx2−to element sulfur is a key measure to resolve the problem on side reaction. [ABSTRACT FROM PUBLISHER]

The reaction between HS- and pentavalent vanadium V(V) and its effect factors, such as reactant concentration, reaction temperature, and the pH value in tannin extract desulfurization technology has been researched in this article. The results show that the reaction between HS- and V(V) is a quick reaction process. When the initial concentration of V(V) increases, the reaction speed accelerates, and the equilibrium conversion of HS- rises. The effect of reaction temperature is smaller in the operation range of tannin extract desulfurization technology, and the reaction speed slows with the pH value enhancing. Additionally, a new reaction mechanism on the reaction between HS- and V(V) was proposed by analyzing the experimental phenomena and the solid product. [ABSTRACT FROM AUTHOR]

To investigate the formation reason of by-products in tannin extract desulfurization, the kinetics of the chemical oxidation of aqueous HS- solutions have been studied in a continuous bubbling reactor. The results show that the reaction rate increased as the initial concentration of HS- increased, and the air velocity accelerated, and reaction temperature rose. The rate equation is -[image omitted] = 1.13 exp(-25622.71/RT)CHS-. By theoretical analysis and experimental research, it is discovered that the oxidation products of HS- are mainly S2O32- and not sulfur. In addition, some suggestions were put forward to reduce by-products. [ABSTRACT FROM AUTHOR]