Study On The Characteristics Of Composite Additives On Microwaveassisted Pyrolysis Of Microalgae And Life Cycle Evaluation Of Microalgae Gasification Generation

Biomass is the most ancient energy and an important energy source on which human beings have been living.Biomass has the advantages of wide distribution,reproducibility,and low coct.It is a carbon-neutral energy source and is considered as one of the substitutes for fossil fuels.As an important part of biomass,microalgae has the characteristics of high fat content,short growth cycle and no occupation of cultivated land compared with traditional biomass,which has attracted wide attention from scholars at home and abroad.Microwave-assisted pyrolysis is a new type of pyrolysis,which has the characteristics of high efficiency,selectivity,and easy control.Its application in microalgae pyrolysis can improve the pyrolysis efficiency of microalgae,the comprehensive performance and economic value of the pyrolysis products.With the continuous development of microwave-assisted technology,microwave-assisted pyrolysis technology has become one of the important methods for the rational utilization of biomass.At present,biomass microwave-assisted pyrolysis mainly focuses on microwave-assisted catalytic pyrolysis and microwave-assisted co-pyrolysis,and the research on microwave-assisted composite catalytic pyrolysis is almost not involved.Therefore,it is very important to study the influence of compound additives on the microwave-assisted pyrolysis characteristics of microalgae,which is of great significance for promoting and developing the energy conversion and application of microalgae.In this paper,the industrial analysis and elemental analysis of microalgae were first carried out,and it was concluded that the fixed carbon and oxygen content of microalgae were high,indicating that microalgae were easy to be pyrolysis and had a great impact on the yield of pyrolysis gas.Meanwhile,high oxygen content could reduce the air supply during pyrolysis.In this paper,the industrial analysis and elemental analysis of microalgae were fist carried out.Then,the microwave pyrolysis characteristics of Si C/Fe₂O₃and Si C/Ca O composite additives under different additive amounts and different blending ratios were studied by using the microwave-assised pyrolysis system,and compared whith single additive and pure.Finally,the life cycle assessment of microalgae gasfication generation system was evaluated.The experimental results were showed that:?1?The fixed carbon and oxygen content of microalgae were high,indicating that microalgae was easy to pyrolysis,which had a great in fluence on the yield of pyrolysis gas,and high oxygen content can reduce the air supply in pyrolysis.?2?In the experiment with Si C/Fe₂O₃ as the composite additive,when the amount of composite additive was 20%and the blending ratio was Si C:Fe₂O₃=3:7and 5:5,the composite additive will had a synergistic effect.At the same time,the largest R_v and M_t in the experiment were 20%Si C:Fe₂O₃=5:5 and 20%Si C:Fe₂O₃=0:10 experimental group,respectively.?3?In the experiment with Si C/Ca O as the composite additive,when the additive amount of the composite additive was 15%and the blending ratios of Si C:Ca O=5:5 and 7:3,the composite additive will had a synergistic effect.Meanwhile,the largest R_v and M_t existed in the experimental 15%Si C:Ca O=5:5and 5%Si C:Ca O=5:5 experimental group,respectively.?4?In the comparison of Si C/Fe₂O₃ and Si C/Ca O pyrolysis characteristic parameters,it was concluded that the two composite additives showed different product tendencies,Si C/Fe₂O₃ composite additive were more conducive to the production of pyrolysis gas,while Si C/Ca O composite additive were more conducive to the production of solid residue.?5?The life cycle assessment of the microalgae gasification generation system with a functional unit of 1MW·h for power generation was carried out,and it was concluded that the total energy consumption of the microalgae gasification generation system in the entire life cycle was 1340.916MJ,of which the largest proportion was the microalgae cultivation stage?54.489%?.The most impact on environment in the life cycle assessment was dust,followed by global warming and acidification,eutrophication of the environmental impact of the minimum.Microalgae gasification power generation had a greater impact on the local,far greater than the global and regional impact,so the power generation system had less negative impact on the environment,will be a kind of refers to the promotion of power generation system.