Pilot Condition Optimization Of Biochemical Loop System For H₂S Removal

Biological-chemical system for H₂S removal is a environmental friendly and low energy consumption new hydrogen sulfide removal technology,how to put it into the industrial application is the research hot spot.However,the technology also exists the problems of the unsustainable running and sulfur precipitation difficult to remove before application.This study based on the previous research in our laboratory is focus on the pilot study and conditon optimaziton of the hydrogen sulfide removal system.The following is the main research contents and corresponding results.1.Additon citrate as chelator of ferric and adoption RSM as optimization's method.A new medium component which has low jarosite,containing higher concentration of ferrous iron and more effective for H2S removal than 9K medium,was developed.i.e.,pH 1.63,ferrous iron,13.42g/L;citrate,1.69g/L;?NH₄?S0₄,1g/L;K₂HPO₄,0.3g/L;MgSO₄·7H₂O,0.5g/L;KCl,0.1g/L;Ca?NO₃?₂ 0.01g/L.2.the method of preservation for Acidithiobacillus ferrooxidans BY-3 in the daily temperature was studied.In giving methods,each method can remain the ferrous oxidated ability within ten days,while there is much difference when preserved time exceeds one month.We found the neutral water is the best choice,and the laters are fresh nutrient medium,1/2 fresh nurtrient medium,oxidized medium,basic salt with pH1.8 and oxidized medium with pH 1.8.3.we studied the characteristic of sulfur precipitation which is formed in the process of H₂S removal.The sulfur precipitation is small particles in the begin whose diameter is only one micrometer.The particles will be bigger and bigger reaching to a 10 micrometer diameter with sulfur accumulating.There is some particles with a diameter over 90 micrometer,identified is jarosite which has a proportion of 10 percent.The sulfur-oxidizing bacteria can grow fastly and take a shorter cultural time with sulfur precipitation instead of natural sulfur.4.The sulfur precipitation's effect on the biological-chemical system was investigated.In the biological system,when the biological system has a 2g/L concentration of sulfur.The ferrous iron oxidization ability is inhibited.The descend of pH contributes to the utilization of sulfur by the bacteria and dwindles ferrous iron oxidation.increasing the ratio of ferrous iron to sulfur can improve the ferrous iron oxidation to some extent.In the chemical system,the bacteria use ferric as the electron acceptor to oxidate the sulfur with lacking oxygen,which gives rise to the decrease of pH.5.A new sulfur separated and removal device was designed.The setup performed good removal efficiency when it tested after connecting it with the biological chemical system.Percent of 40 to 60 precipitation is blocked as the mixed liquor containing sulfur flow through the filter layer.The total removal quantity is percent of 60 to 80 after standing one hour and over percent of90 is removed after four hours dwelling.6.The process of the H₂S removal and the system was redesigned.The new chemical system is made up of two H₂S removal reactor,namely,high conentration of H₂S removal reactor and low H₂S removal reactor,And the system reaches to 100%removal for H₂S and beneficial for sulfur recovery.