Experimental Study On Low-temperature Denitrification Of Microalgae Biochar

Atmospheric environmental pollution is a major issue related to social development and people’s health.Nitrogen oxides in the flue gas pollutants of the power industry are one of the main hazards to the atmospheric environment.The emission of nitrogen oxides will cause the formation of acid rain and photochemical smog.The large-scale industrial application of SCR denitration catalysts has high cost and narrow temperature window.The denitration catalysts modified by physical coke as a carrier through physical and chemical modification have become a research hotspot in recent years.This technical route supports metal active components and Modification will increase the cost and complexity of the catalyst preparation process.Microalgae is a kind of biomass resource with wide sources and many types.The high-value utilization of pyrolysis products of microalgal biomass has broad research prospects.Research on microalgae biochar and use its nitrogen-rich characteristics to explore the feasibility of original nitrogen-rich biochar in the denitration reaction is of great significance.In this paper,the high-value utilization of microalgae pyrolysis products is taken as the research background.Two types of microalgae with high nitrogen content are selected as the research objects.First,pyrolysis is used to prepare microalgae biocoke with high reactivity to explore pyrolysis.Explore the effect of pyrolysis temperature on its physicochemical properties;Secondly,the denitrification performance of microalgae biocoke was tested,the evolution trend of nitrogen-containing functional groups before and after the microalgae pyrolysis was involved in the denitrification reaction,The influence of the reaction temperature on the denitrification efficiency of microalgae coke in the denitration experiment was investigated.Finally,the overall process flow of the microalgae biocoke denitration technology is designed,combined with equipment selection,initial investment and operating cost estimation,to analyze the economics of the microalgae biocoke denitration technology,which provides theoretical basis and reference for practical application.The results of the study indicate the following:The microalgae boichar surface has abundant nitrogen-containing functional groups,most of which exist in the form of pyridine-N,followed by pyrrole-N,amineN and quaternary amine-N.The specific surface area and pore volume of the two types of algae boichar are low,and the physical morphology of the boichar surface is complex;as the pyrolysis temperature increases,the microalgae boichar yield gradually decreases,and the total pore volume of the microalgae boichar increases;When the temperature is 200 ℃,the denitration efficiency of microalgae boichar is 47%.Pyridine-N,quaternary amine-N and pyrrole-N are the key functional groups participating in the denitration reaction,and the oxide of pyridine-N is the main reaction product;with the increase of the reaction temperature,the efficiency of the denitration reaction of chlorella coke gradually increases.When the reaction temperature is 300 ℃,the denitration efficiency can reach 53%;the denitration cost of microalgae boichar is about 6964.130 yuan / t,and the microalgae boichar denitration process is technically and economically feasible.