Study On Hydrodynamics Of Biomass Fast Pyrolysis Double Fluidized Bed Reactors

In renewable energy,biomass has many advantages(low sulfur,nitrogen,carbon dioxide "zero emissions"),make it as a new energy.The use of common biomass energy includes biological and thermochemical conversion.Among them amethod of rapid pyrolysis in thermochemical conversion is commonly used for the preparation of liquid fuels.A dual fluidized bed reactor has the advanta ge of self heating and is therefore widely used in thermochemical conversion.Due to the complicated rapid reaction of biomass pyrolysis,the conditions of reaction are demanded,theoretical simulation is a kind of research method.The rapid pyrolysis process is very sensitive to the fluid flow of the reactor.Therefore,it is important to study the hydrodynamics of the rapid pyrolysis of biomass double fluidized bed for the industrialized amplification design.The study of the hydrodynamic study of double fluidized bed,including the combination of hot and cold states and the separation efficiency of cyclone separators,can provide reliable theoretical guidance for the design and experimental study of double fluidized bed reactor.In this study,the theoretical model of hydrodynamics was obtained by evaluating the theoretical hydrodynamic model,and the fluidized bed and the cyclone separator were simulated by ANSYS FLUENT software.In this paper,the hydrodynamic model of the fluidized bed of the riser under the cold state is built as follows,by adjusting the volume fraction of the height of the riser at different wind speeds and comparing with the experimental results,the appropriate riser grid model is found,Then temperature,air viscosity and other parameters of this model will be applied to the hot riser fluidized bed fluid dynamics study hence to find the relationship between the volume fraction of sand,after that,dynamic model for the riser under the hot state isestablised.C yclone separator is an important equipment of double bed,which relates to the heat transfer of biomass pyrolysis,the mass transfer and the final quality of bio-oil.In this paper,a three-dimensional hydrodynamic model is established for the cyclone separator.The separation efficiency of the carbon particles is found,and the relationship between the collection efficiency and the particle size of the carbon particles is found when the outlet of the cyclone separator has loose winds and no loose winds.The relationship between the volume fraction of the riser between the cold preheating is found by the cold CFD model.The mathematical relationship between the hot and cold sand is obtained.Before the thermal biomass can be run.To guide the hot process and equipment and provide some feasibility recommendations.Since the biomass feed particle size is 1 mm,the carbon particles decrease due to grinded and the collection efficiency decreases,as well as BFB temperature also drops,it can be fed by increasing the particle size of biomass such as 2mm,so that the collection efficiency may be better,and the whole process is carried out continuously provide ing the desired temperature.