Catalytic Upgrading Of Pine-nut Shell Vapors By Ni/HZSM-5 And Ni-Co/HZSM-5

With the global warming and the decrease of fossil energy,the development of renewable energy has become an important issue for the development of human society.Biomass energy,as a meaningful environmental solution,has been widely concerned.Biomass with large reserves and wide distribution has the advantages of traditional fossil energy and other new energy,which is expected to become a new energy instead of traditional fossil energy.According to the research results,biomass energy accounts for 14%of the world’s total ene rgy.In the future,nearly 1/3 of the global transportation fuel can be supplied by biomass and other wastes.Because of its low cost and environmental protection,biomass is expected to become the main source of primary energy raw materials in developing countries.Catalytic pyrolysis is a thermochemical conversion technology,which provides a commercially viable way to produce bio-oil from a variety of biomass raw materials.In this paper,the recycling and utilization of biomass energy in pine-nut shell were realized by catalytic pine-nut shell vapors.In this paper,the catalytic temperatures（500-800°C）,catalytic pressures（0.1-0.6 MPa）and catalyst types（Ni/HZSM-5 and Ni-Co/HZSM-5）in the process of catalytic pine-nut shell vapors were optimized.By studying the yields of the product,the physical and chemical properties of bio-oil and syngas.The differences of the reaction mechanism between atmospheric pressure catalysis and pressurized catalysis were analyzed,and the optimal process flow under atmospheric pressure and pressurized condition is determined.Compared with previous studies,the catalytic effect of catalytic pine-nut shell vapors process was analyzed,and the catalytic biomass vapors and catalytic bio-oil process were compared.The results show that the optimal process of catalytic pine-nut shell vapors under atmospheric pressure is as follows:the mass ratio of pine-nut shell to catalyst is 10:1,the pyrolysis temperature is 500°C,the catalyst is Ni-Co/HZSM-5,and the catalytic temperature is 650°C.It was found that the total energy yield was 98.78%,and the high heating value of bio-oil and syngas were 33.92MJ/kg and 18.97 MJ/m³,respectively.The optimal process of catalytic pine-nut shell vapors under pressure catalysis is as follows:the mass ratio of pine-nut shell to catalyst is 10:1,the pyrolysis temperature is 500°C,the catalyst is Ni-Co/HZSM-5,the catalytic temperature is 500°C,and the catalytic pressure is 0.6 MPa.The results show that the total energy yield of the product is as high as 99.38%,and the high heating value of bio-oil and syngas are 34.63 MJ/kg and 20.34 MJ/m³,respectively.Compared with previous studies,it was found that the content of phenolic compounds in the bio-oil of pine-mut shell was higher,while the selectivity of Ni/HZSM-5 for phenolic compounds was higher.Therefore,Ni/HZSM-5 catalyst was suitable for the catalytic pine-nut shell vapors.At the same time,the addition of Co also enhanced the cleavage of C-O bond and promoted the hydrodeoxygenation of phenols,which made the catalytic effect of Ni-Co/HZSM-5 superior to that of Ni/HZSM-5.In addition,from the perspective of comparative analysis of catalytic the bio-oil of pine-nut shell and catalytic pine-nut shell vapors process,catalytic pine-nut shell vapors can make H₂,CO and CH₄ produced in the pyrolysis stage participate in the addition and alkylation reaction s in the catalytic stage,resulting in the physical and chemical properties of the bio-oil produced by catalytic pine-nut shell vapors is better than that of catalytic bio-oil of pine-nut shell process.This is the essential difference between the two processes.To sum up,the catalytic biomass vapors is superior to the catalytic bio-oil.