Experimental Study On The Fast Pyrolysis Of The Bio-mass For Producing Bio-oil

Energy shortage and environment pollution have caught people’s attention in thewhole world increasingly. Therefore, looking for the renewable clean energy hasbecome the inevitable trend with the development of our society. The reserve ofbiomass energy is huge and biomass is the only renewable carbon source. Biomasscan be converted to bio-oil through thermal chemical method. The energy density ofbio-oil is larger and the transportation is more convenient. Bio-oil can provide energysource for people’s life and production.In this paper, the influences of various factors on the fast pyrolysis have beenstudied and the optimum conditions for producing bio-oil have been sought in theself-made fluidized bed reactor by using rice husk as the raw material.First, according to the predetermined processing, the experimental devices whichincluded the fluidized bed reactor, the cyclone separator, the condenser, the feedingdevice, the heating equipment and other equipments were designed. The devices weremanufactured, installed and tested according to the design results.Second, the components of the rice husk were tested and the result showed thatthe volatiles and ash content in the oven dry rice husk were66.43%and17.03%respectively. The thermo-gravimetric analysis of the rice husk showed that thepyrolysis process included the dehydration, the cracking and the coking stage. Theweightlessness rate was maximum at360℃. The particle size of the shredded ricehusk was analyzed and the result showed that the particle size mainly distributedbetween0.2mm and0.45mm.Third, the single factor experiments on the fast pyrolysis of the rice husk werecarried out. The influences of the reaction temperature, the carrier gas flow rate, thefeed rate and the particle size on the fast pyrolysis of the rice husk were studied. Theoptimum conditions for producing bio-oil were found to be520℃,22m3/h of thecarrier gas flow rate and1177g/h of the feed rate. The small particle size wasbeneficial for increasing the yield of bio-oil, but the effect was not obvious when the particle size was under20sieve mesh. The components of the bio-oil which producedin the optimum conditions were analyzed through the GC-MS method. The resultshowed that bio-oil was a kind of mixture that contained organic acids, ketones,aldehydes, esters, phenolics and other heterocyclic compounds. The bio-oil requiredfurther treatment because of the high content of oxygen.Finally, the response surface optimization experiments on the fast pyrolysis ofthe rice husk were carried out. The yield of the bio-oil was selected as the responsevalue and the reaction temperature, carrier gas flow rate and feed rate were selectedas the three influencing factors. The interaction between various factors was analyzed.The optimal conditions were found to be531.83℃,23.88m3/h of the carrier gasflow rate,1176.16g/h of the feed rate. Then, three sets of parallel tests were carriedout. The result showed that the average yield of the three groups of parallel tests was41.87%which was in conformity with the predicted value (42.84%).