Process Analysis And Experimental Research Of Staw Pyrolysis In Biomass Rotating Bed Reactor

In order to research the basic theory and the pyrolysis effect of straw in biomass rotating bed reactor,conducted the process analysis and experimental research of staw pyrolysis.Firstly,a general model of biomass thermal conversion was constructed and analyzed.Through the energy analysis of biomass stability process pyrolysis in the pyrolysis reactor,established a chemical energy equilibrium thermodynamic model.Based on the model analysis,a biomass rotating bed pyrolysis reactor was designed and realization.The reactor comprises a rotating,a feeding part,a cyclone,a condenser,a frame,etc.The reactor has higher adaptability of the material and can reduce the occurrence of the two-reaction,and make the biomass and the heat carrier mixed and fluidized fully.The new pyrolysis process can be carried out without the addition of carrier gas and pressure reaction.The reactor has the advantages of simple structure,low cost,simple operation,strong controllability and low cost.The rotating bed is the key component of the reactor,and biomass pyrolysis,fluidifying and mixing with quartz sand are completed in the interior.Based on the discrete method,the effects of rotating speed,feed speed and flight situation on the contact particle number rate and tatal particle velocity of biomass and quartz sand were analyzed by EDEM software simulation.The optimal parameters of the maximum contact particle number rate were obtained,which the ratating speed of ratating cylinder is 27.6 r/min,the feeding speed is 2.48 kg/h and no flights.The optimal parameters of the maximum tatal particle velocity were obtained,which the ratating speed of ratating cylinder is 62.1 r/min,the feeding speed is 1.55 kg/h,flights number is 6 and the height is 0.6cm.The flow field of the pyrolysis gas in the rotating bed was analyzed by fluent software,and the of the pyrolysis gas in the rotating bed was less.It proved that the pyrolysis gas effect of mixing and fluidization of biomass and quartz sand is limited and the rotating bed reactor can reduce the two-reaction.At the same time,fluent software was used to analyze the pressure and velocity of cyclone and condender,the results show that the cyclone and condenser meet the design requirements.The frame is an important part to support the normal and stable operation of the reactor,and thermal structure coupling finite element simulation analysis is carried out.The steady thermal analysis,static analysis and modal analysis of the frame were carried out by using Ansys Worrkbench software,it shows that the heater has little influence on the working environment and the structure is stable.A variety of parameters of corn straw pyrolysis were carried out based on ratating bed reactor,including the parameters of the ractor,the atmosphere of air and the pretreatment of staw.The machine parameters include reaction temperature,feed rate and rotational speed.The heat value and elemental analysis were carried out to biochar,the heat value,moisture content and elemental analysis were carried out to bio-oil,and the compostion and content of organic compounds were analyzed by gas chromatography to syngas.At 371.1 ?,it showed the lowest moisture content,the highest heat value and the highest carbon content of bio-oil,371.1? was the suitable pyrolysis temperature.When the rotating speed was 62.1 r/min,the reaction was more abundant and the content of organic matter in the bio-oil was at least 13.49%.It showed the best comprehensive effect of mixing and fluidization of biomass and quartz sand.The effect of gas atmosphere on the biomass pyrolysis is significant;the experiment of rotating bed reactor was conducted under three kinds of atmosphere,including no carrier gas,exhaust gas as carrier gas and N2 as carrier gas.When the exhaust gas passes,the biomass reaction was the most abundant,and can increase the reactivity of H element.And the content of in bio-oil is higher,and the molecular weight was smaller.The nitrogen can reduce the occurrence of two-reactions.Based on the reactor,the pyrolysis experiments were carried out with different pretreatment materials,including the drying pretreatment,grinding pretreatment and baking pretreatment.The pyrolysis reaction of particles on the surface of the large particles is more abundant,but the pyrolysis reaction does not enter the interior of the particles.The moisture content of bio-oil with high moisture content biomass was significantly increased,as high as 85.15%.It can be concluded that the moisture content of biomass will hinder the process of biomass pyrolysis.The baked biomass has low reactivity and it will reduce the organic content of bio-oil.