S Zorb反应吸附脱硫反应过程的热力学分析

Thermodynamic analysis on the process of S Zorb reaction adsorption desulfurization

S Zorb技术可以将FCC汽油的硫含量降至小于10μg/g,但在反应吸附脱硫过程中,由于反应体系中引入了H2,在反应器中不仅发生了硫化物的脱硫反应,还会发生不饱和烃的加氢饱和反应、加氢异构化反应和烯烃与H2S生成硫醇的反应。本文采用基团贡献法Benson法分析了这些反应的热力学性质,计算了这些反应的反应焓变?rHm、反应吉布斯自由能?rGm和反应平衡常数K及平衡转化率。计算结果表明,本文所列举的7个典型反应都是放热反应,且有芳烃加氢放热>噻吩化合物脱硫放热>烯烃加氢放热>烯烃与H2S生成硫醇放热>烯烃加氢异构放热;在S Zorb反应吸附过程中,体系中H2S含量较少,因此噻吩脱硫后不会继续生成硫醇。

S Zorb process can reduce the sulfur content in gasoline to less than 10μg/g. But because of the addition of H2,not only the desulfurization reactions of sulfur compounds occur on the surface of the adsorption , but also the hydrogenation reactions of olefins and aromatics and the hydroisomerization reactions are associated during S Zorb reaction adsorption desulfurization. The thermodynamic properties of these reactions were analyzed in this paper,including reaction enthalpy, Gibbs free energy,equilibrium constant and thermodynamic conversion. The results show that all these typical reactions are exothermic and the order of heat release is as follows：aromatic hydrogenation＆gt;thiophene desulfurization＆gt;olefin hydrogenation＆gt;the generation of mercaptan＆gt;olefin isomerization. The results also show that mercaptan could not be produced after the thiophene desulfurization because of the less content of H2S in the reaction system during S Zorb reaction adsorption desulfurization.