Process Design And Optimization Of Wet Desulphurization In Biogas Engineering

Biogas has been paid more and more attention as one of the most important biogas.Large-scale biogas project can fully realize the reduction,harmlessness and resourceutilization.The amount of the by-product H2S of biogas project is small,but it is very harmful.So it is an essential link in the biogas project.In this work,based on the chemical absorption method,wet desulfurization technology is applied to large-scale biogas project,the biogas desulfurization system was designed and constructed for a dairy-farm biogas project,the orthogonal test was used to determine the effects on the desulfurization efficiency of the system,the optimum operating condition of the system is determined,the field operational aspect and structure of operation cost are summarized and prospected.The main research are as follows:(1)According to the requirements of biogas generating equipment,H2S in biogas should be less than 200ppm,a set of biogas desulphurization processes were designed and set up,including biogas desulphurization,desulfurization liquid regeneration,elemental sulfur recovery and so on,which can realize multiple effects such as efficient desulfurization,resource recycling.(2)According to the biogas production,composition and biogas desulfurization target of the project,the sizes and parameters of the core equipments of the system were calculated and determined,including the desulfurization tower,DN2000×H12000 with 4 floors,including spray amount 32.6 m3/h,spray density 15.92 m3/(m2 h),liquid-gas ratio 84.6 L/m3;regeneration tank's inner cylinder DN1600×H2500,outer cylinder DN2000xH4500;liquid tank DN3000 x H2500,liquid tank DN2000 x H1200,solution heater heating area 13.5m2 and so on.(3)The orthogonal test was used to determine the effects of temperature,HE101 dosage and pH(8-9)on the desulfurization efficiency of the system,and the optimum working conditions were as follows:temperature 35?40?,HE101 dosage of 35?40g/d,pH8.3?8.6,Na2CO3 dosage of the best range of 25?30kg/d.(4)After the biogas treatment,the H2S concentration decreased from 3704.1ppm to 53.22ppm,with the average removal efficiency of H2S reaching 98.57%and the desulphurization effect better,the quality of biogas improved;The average solid content of elemental sulfur generated was 56.4%,after further compression treatment,making the mud cake with a good economic and value in use.While the system operating cost is 0.037 yuan/(Nm3·d).(5)By calculation,the operation cost of the system is 0.037yuan/(Nm3·d),the prime cost is power consumption,the cost of desulfurization reagent only accounted for 22.8%of the total cost.The regenerative pumps accounting for 54.7%of the total expenses.In this work,according to the study of application of wet desulfurization in large-scale biogas project,we confirmed that wet desulfurization technology has the advantage of high desulfurization efficiency,regeneration of desulfurization solution,and recyclable sulfur products.And the low cost in large-scale biogas engineering provides reference and design basis for research on desulfurization technology of large-scale biogas engineering.