The Kinetics Of The Selective Oxidation Of Hydrogen Sulfide And The Mathematical Simulation Of The Reactor

Due to the limitation of thermodynamic equilibrium in traditional Claus process,the content of hydrogen sulfide in tail gas is difficult to meet the requirements of environmental protection.Industries often adopt series adiabatic reactor to deal with this part of tail gas,but the capacity of reactor treatment is small.Moreover,the concentration of H2S in the inlet is strictly restricted.With the industrialization of high efficiency catalyst for selective oxidation of hydrogen sulfide to sulfur,the research on the reaction kinetics model and the reactor design of the catalyst has become a hot spot.In this paper,the thermodynamics,kinetics,optimization of process conditions and reactor design of the selective oxidation of hydrogen sulfide to sulfur were studied in the basis of catalyst LS-06 which was developed by Qilu Branch of Sinopec.The main contents and conclusions of this paper are as follows:(1)the thermodynamic calculation results show that the main reaction of selective oxidation of hydrogen sulfide is an irreversible strong exothermic system,and the equilibrium constant of the reaction shows that the low temperature is favorable for the main reaction.(2)In the micro-reactor(Φ10,L=110mm),the kinetic experiments are carried out on the H2S 0.5-4.5%,the O2 0.25-2.25%,the N2 93.25-99.25%of the different components under the conditions of the LS-06 catalyst,the pressure of 0.1 MPa,the reaction temperature of 170-250℃,the space velocity of 600-1200 h-1.According to the Langmuir-Hinshelwood theory,a selective oxidation kinetic model of hydrogen sulfide is established,and the statistical test and the residual analysis show that the model is suitable.The working condition of the adiabatic reactor based on the industrial operation is simulated and the applicability of the established dynamic model to the industrial device is verified.(3)The reaction process was realized in two-stage packed tubular-shell reactor,and a one-dimensional quasi-homogeneous mathematical model was established.Because the reaction system gives out a large amount of heat and there is a large radial temperature difference in the reaction bed,a two-dimensional quasi-homogeneous phase model is established and solved by Runge-Kutta method.The optimization of technological parameters shows that 28mm pipe diameter,the optimum feed temperature 205℃,the optimum hydrogen sulfide-oxygen ratio 2,the space velocity 70h-1,and the optimum cooling medium temperature at 200℃ are the most suitable.(4)Based on the disadvantages of the two-stage packed tubular-shell reactor,such as small specific heat transfer surface,bed flying temperature and poor operation stability,the design conception of the new type plate reactor is put forward.The calculation results show that the new reactor has remarkable heat transfer effect,precise control of reaction hot spots and other advantages.