Research On Design Theory And Simulation Of Biomass Pyrolysis Liquefaction In Suspension Fluidized Unit

Biomass energy is a kind of renewable energy.It is important to exploit and utilize biomass energy.Energy shortage can be relieved,fossil fuels utilization can be reduced and energy construction can be modified in the future.It is an important method of biomass energy development and research to transform biomass to high quality liquid fuels through fast pyrolysis of biomass technology.This paper based on research achievement of the biomass of the civil and foreign country about making bio-oil from fast pyrolysis of biomass.The theory is developed on the biomass suspension fluidized bed.The theory analysis and simulation can be executed.The theory involved the law of motion,the law of pyrolysis and design theory about biomass suspension fluidized bed.In the first place,the research background of science project is putted forward.The biomass species and biomass energy transformation and utilization technology are expounded. The domestic literature review and foreign literature review are analyzed on the making bio-oil technology form biomass fluidized pyrolysis.The research direction and research hot spot are grasped roundly in this domain.The granule and chemistry characteristic of biomass raw material are analyzed.The biomass cooling fluidization test-bed is established.Corn cob and rice hull fluidization experiments are executed separately,then,the mixture fluidization experiments are executed. Biomass fluidization experiment indicated that pure biomass fluidization is well achieved.The granule of biomass raw material is small and fluidized characteristic.The variety of pressure of every test point is not distinct.The variety pressure has not definite regularity.The mixed biomass fluidization experiment indicated that the biomass quality ratio is different and fluidization and pressure variety have not prominent difference.The mixed biomass critical velocity is small.The instantaneous flow of images of granule in bed has been received by the method of high-speed camera.The granule speed chart have been received by analysis of the particles image.Image analysis shows that the biomass and quartz sand mixed well in the bed and no obvious phenomenon of layered.The quartz sand at lower part of the bed accumulates a larger concentration for the axial mixing.Particles in the bed have a violent change in velocity and have a uneven distribution in velocity.As the biomass flow of movement complexity,poor reproducibility experiments,it is difficult accurately measured experimental values.As a result of the complexity of the fluidized movement of biomass,it is difficult to comprehensive understand the flow discipline of gas-solid phase through a limit test in the bed. So,the basic differential coefficient equations of gas-solid phase have been established.The movement simulation of gas-solid phase has been carried using Euler two-fluid model calculation of Fluent software.The solid speed distribution of cloud chart and solid volume fraction distribution of cloud chart have been received along the direction of the bed as the time change.The results show that two different structures of the bubble phase and dense phase can be seen inside the bed.Solid-phase particles in the bed have the circle of movement.The formation and the breakdown of the bubble have a cyclical change.These behaviors are in favor of mixture and separation of biomass.Through the simulation,the gas-solid characteristics of the movement in the bed have more accurate description and more knowledge of biomass fluidization characteristics.According to the Waterloo university pyrolysis mechanism model,the pyrolysis kinetics equation of biomass has been established.The biomass quality along with the pyrolysis temperature change curve has been received through solving equation.The curve analysis shows that the temperature is an important parameter influencing biomass pyrolysis.The production of Char increases with temperature,and gradually moving to a fixed value.The bio-oil production with the temperature increases and in the 800-900K,bio-oil production to reach the maximum.The pyrolysis curve by solving equation with the previous results are basically the same.It is illustrated that the establishment of the equation is credible.The formula can predict the impact of the temperature with biomass pyrolysis product.The heat transfer of biomass pyrolysis is complex,through the pyrolysis process analysis,the heat transfer equation of biomass have been established.According to the preceding design theory and testing results,the heat input of reactor are discussed,the new set of suspension biomass pyrolysis for bio-oil is developed.The method of the heat input use burning fuel gas by biomass gasification.Non condensation gas producted by pyrolysising biomass entered reactor by conducted fluidized gas.The heat of burning biomass fuel gas can reduce the use of other energy sources.Be able to take energy and produce on the spot.To maximize the conversion of local raw materials to produce material for the use of clean energy and reduce bio-oil costs by biomass pyrolysis.The heat input gas burner by burning fuel gas is designed,and energy balance of the reactor were calculated.In the end,the full-text of the final paper is summarized.