The Design Of Biomass Fluidized Bed And Research On The Bio-oil Production By Pyrolysis

The research of biomass pyrolysis liquefaction has great significance for using thehigh-grade bio-oil, solving the problem of energy shortage and improving the ecologicalenvironment in the context of deepening energy crisis and environmental pollution.Therefore, in this paper, the fluidized bed reactor for biomass pyrolysis liquefaction wasdesigned and a series of experiments were conducted on it. The research content and theresults are as follows:Firstly, through the analysis and comparison of domestic and international existingbiomass pyrolysis liquefaction plant, the fluidized bed reactor was considered as an idealone. According to the design principles and formulas of the fluidized bed reactor, a newtype of fluidized bed reactor system (76mm in diameter and1000mm in height) wasdesigned, and its main components were as follows:(1)Through improving the existingtwo-stage screw feeder, a pressure port was setted up in the silo to ensure the continuity offeed.(2)The intake device included elbow pre-distribution and the dense pass gasdistribution plate which was adopted on equilateral triangle line.(3)The gas-solidseparation device consisted of two cyclones in series which the inner diameter was80mmand40mm respectively.(4) The second condensation was used for the bio-oil quenchedand collected.Secondly, based on spin-down method, a series of fluidized-bed cold-stateexperiments were carried out in a plexiglass tube with an inner diameter of76mmandaheight of1000mm. The effect of fluidization characteristics of blue algae, pine andquartz sand was studied by the investigated material particle size, the particle size of thequartz sand, the opening rate of the air distribution plate and quartz sand mass ratio. Theresults showed the best combination of fluidization quality of blue algae, pine and quartzsand. The knowledge obtained would provide the required parameters for the thermalexperiments.Finally, the influence of different temperatures on the pyrolysis product yield andcomposition in the basis of cold-state experiments were conducted with the pine and bluealgae as raw materials. The results showed that:(1) The fluidized bed reactor could beused for biomass fast pyrolysis liquefaction and get a high oil production rate.(2) With the temperature increase, the gas yield of pine and blue algae gradually increased, while thechar yield gradually reduced and the oil yield first increased and then decreased. When thepyrolysis temperature was500℃, the oilyield of sawdust and blue algae reachedmaximum of45.2%and50.4%respectively.(3)The bio-oil composition from pyrolysis ofpine and blue algae were significantly different: the former had a higher level of acids,esters and phenols compounds, and the latter had a higher level of nitrogenous compoundsand ketenes compounds.