Desulfurization Of Biogas Through Alkali Chemiscal Absorption Combined And Biological Methods

A large amount of biomass waste is generated in China every year,and if not properly disposed of,it will easily cause serious environmental pollution and waste of resources.There are many treatment methods for biomass waste.Among them,biomass waste is used as a substrate for anaerobic fermentation to prepare biogas,which can not only efficiently use a large amount of biomass waste produced in China,but also alleviate the energy crisis facing China.The production of biogas is often accompanied by the generation of hydrogen sulfide.Hydrogen sulfide is a highly toxic gas and is acidic.It is corrosive to metal parts.If it is not removed in the later use of biogas,it will pose a great threat to the life of the operator and will corrode the pipeline,Valves and other equipment cause economic losses.Sulfur dioxide is also produced after the combustion of hydrogen sulfide,which is the main component of the formation of acid rain.Therefore,the removal of hydrogen sulfide gas from biogas is the only way to achieve high value-added utilization of biogas.Biogas desulfurization methods include in-situ desulfurization,dry desulfurization,wet desulfurization,biological desulfurization,and membrane separation desulfurization.Among them,alkaline chemical desulfurization in wet desulfurization has been widely used because of its mature technology,low cost,good effect,and stable operation.However,the reaction product of alkaline chemical desulfurization agent and hydrogen sulfide is often difficult to regenerate,which affects the further development of alkaline chemical methods.Biological desulfurization is an emerging desulfurization method,but there are problems such as immature technology and unstable operation.In response to these problems,this article puts forward two complete desulfurization methods:"alkali chemical absorption+biological desulfurization" and "alkali chemical absorption+deep oxidation",carried out process simulation,test device design and laboratory research,and designed an industrialized device The main research contents and results obtained are as follows.1.Carried out the whole process simulation of biogas alkali chemical absorption desulfurization and "alkali chemical absorption+biological desulfurization".Use Aspen Plus software to change the mole fraction of water and potassium hydroxide in the feed one by one under the four conditions of 202.65kPa-20?,202.65kPa-25?,303.975kPa-20? and 303.975kPa-25?,respectively.Calculate the removal rate of hydrogen sulfide in the column gas phase.The simulation results show that,compared with the absorption temperature,the absorption pressure has a more significant effect on the absorption effect,and can achieve a better absorption effect at 303.975kPa-20? and 303.975kPa-25?.Aspen Plus also theoretically verified the feasibility of the whole process of alkaline chemical absorption and sulfur-containing absorption of rich liquid biological regeneration.2.Completed the design of biogas alkali chemical absorption desulfurization test device.According to the parameters such as liquid intake,air intake,hydrogen sulfide content in the gas entering the tower,and type of packing,a small pilot plant for chemical absorption and desulfurization of biogas alkali was designed.The final forming tower has an internal diameter of 46mm and an external view of 50mm.The effective height of the tower is 2.6m,and the height of the packing layer in the absorption section can be up to 2.5m.The processing capacity of the device is that it can be used for biogas alkali chemical absorption test.3.Carried out an experimental study on the biological oxidative desulfurization of sulfur-containing absorption rich liquid.Use sodium hydrosulfide to dispose the sulfur-containing absorption rich liquid in the self-designed aerobic reactor at 20?,25? and 30?,with 5mg/L,7.5mg/L and 10mg/L dissolved oxygen concentration.Oxidation test,and the sulfur element and microbial community in the reactor were determined by liquid chromatography-ultraviolet detector combination method and high-throughput sequencing method respectively.According to the test results,with the same temperature,the higher the dissolved oxygen,the higher the sulfide removal rate;Similarly,under the same dissolved oxygen condition,the higher the temperature,the higher the sulfide removal rate.Elemental sulfur is produced in the oxidation test.Among the identifiable microbial populations,Pseudomonas spp.possessing the ability to metabolize sulfur has a higher content of Thiopseudomonas.4.Designed a 800m3/h biogas "alkali chemical absorption+biological desulfurization" industrialization device.Based on the industrial application level,the design and selection of process selection,material balance,main structures and key equipment were carried out.After the construction of the project is completed,it can process 800m3 of biogas per hour,the methane content of the bio-natural gas from the tower is 95%,and design a supporting biological desulfurization device that can be used for further engineering applications and research.5.Designed a 800m3/h biogas "alkali chemical absorption+biological desulfurization" industrialization device.Based on the industrial application level,the design and selection of process selection,material balance,main structures and key equipment were carried out.After the construction of the project is completed,it can process 800m3 of biogas per hour,the methane content of the bio-natural gas from the tower is 95%,and design a supporting biological desulfurization device that can be used for further engineering applications and research.