Applicational Study On Catalytical Technology For Biogas Desulphurizing In Gaobeidian Wastewater Treatment Plant

This paper has researched the pilot test on PDS desulphurization technology inGaoBeidian sewage treatment plant, and set up a pilot unit with PDS desulphurizationtechnology for GaoBeidian sewage treatment plant. The paper also designs adesulphurization project using PDS technology for the second-stage of digestionsystem of GaoBeidian sewage treatment plant with economic analysis. The mainresults are:1) The pilot test unit has been improved by these methods: adding NaHCO₃tothe Na₂CO₃liquor which has the high buffer capacity for the H₂S, addinghydroquinone and ferrous sulfate as the cocatalyst, which highly promoted thedesulphurization effect; taking the advantage of the eddy insolation air bound oilprinciple, the pilot test solved the difficult problem of sulfur regeneration; optimizingthe outlet of the regenerated tank, which combines the floatation and sedimentationtechniques.2) The research on single-tower single-stage PDS desulphurization determinedthe parameter of the temperature is35℃,the PDS density is5mg/L, and the pH is8.5; the best parameter of the sprays is: liquid-gas ratio30L/m³, sprays capacity2600L/h, spray density20m³/（h.m²）. The single-tower single-stage desulphurizationefficiency is70%, which is under the design current capacity and the best parametercondition.3) The research on three-tower series two-stage of PDS desulphurizationdetermined the best parameter of the system is: biogas capacity70Nm³/h, the addingquantity of PDS for the first stage reaction tank is3mg/min, the second1mg/min,the best parameter of the sprays for the ф400-tower is: liquid-gas ratio30L/m³,sprays capacity2600L/h, spray density20m³/（h.m²）, for the ф300-tower is:liquid-gas ratio15L/m³, sprays capacity1200L/h, spray density15m³/（h.m²）, andfor the ф200-tower is: liquid-gas ratio15L/m³, sprays capacity1000L/h, spraydensity30m³/（h.m²）. The three-tower series two-stage of PDS desulphurization canmaintain the elimination rate of the H₂S above90%, which is under certain control. 4) It has been observed that, both for single-tower single-stage and three-towerseries two-stage PDS desulphurization, the efficiency could be over90%with thereaction time more than20seconds, and increased slowly after25seconds, andfinally constant after40seconds.5) This paper designs a desulphurization project using PDS technology based onthe pilot test results for the second-stage of digestion system of GaoBeidian sewagetreatment plant （biogas26500Nm³/d） with economic analysis. The project usestwo-tower series two-stage of PDS desulphurization, two series parallel runnings（each is550Nm³/h）. The total investment of the project is about4.24million yuan,and the running costs of the project are about:0.38million yuan/a,0.054yuan/m³.