| As a renewable energy source, biomass is the most effective way to solve theenergy shortage and environmental pollution. With the development and utilization ofbiomass energy, biomass energy utilization technology has been promoted rapidly, asthe thermo-chemical conversion technology, pyrolysis of biomass is one of the mostpotential for development of cutting-edge technology, which has been reached at a widerange of applications. However, the traditional cracking technology has the shortcomingof high energy consumption, complicated operation and long reaction cycle, so lookingfor a high efficiency of biomass pyrolysis is an important task of today’s energydevelopment and has also an important significance.Methyl cellulose, qualitative filter paper and the peanut shells in the suburbs ofChongqing were investigated as the research object, ionic liquid1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was used as an additive with the modifiedhousehold microwave oven as heating device for the fast pyrolysis, with the metalchloride, inorganic acids and the molecular sieve as catalyst, and through a series ofexperiments to determine the optimal experimental conditions for the microwavepyrolysis of biomass. Under the optimum conditions of800W microwave power, withthe ratio of methyl cellulose, qualitative filter paper and the peanut shells of0.20,0.50and0.40respectively, the maximum yield of bio-oil was up to32.26%,37.41%and25.52%in25min. At the same time, the content of biomass composition will also affectthe distribution of pyrolysis products, such as cellulose which pyrolysis to generate agreater amount of volatile substances, and the main component of bio-oil were furfuralcompounds, while the acidic substances were mostly generated by hemicelluloses,lignin contribution to the solid coke and the main component of bio-oil were phenolsubstances. When catalysts were added, the biomass pyrolysis time was shortened byabout60%, and the reaction time was dropped from25min to10min. In addition, thepresence of catalysts can promote the yield of target products and increase theutilization of the bio-oil. Ionic liquid [BMIM]Cl could be recycled and reused afterreaction, it has the merit of the green environment protection and so on.The changes of function in the original and [BMIM]Cl treated biomass wereanalyzed by infrared spectrum, it is showed that [BMIM]Cl has a greater impact toreduce the degree of crystallinity of biomass. The main chemical components and contents of bio-oil were analysis by gas chromatography-mass spectrometry technique.The main components of bio-oil included methoxy acetaldehyde, furfural, acetic acidand phenol. In addition, differences in biomass composition (cellulose, hemicellulosesand lignin) would also have an impact on the pyrolysis products, in the other words, thepyrolysis products depends on the different type of biomass. The compositions ofbiomass pyrolysis gas were obtained by gas chromatography and the main componentswere CO, CO2, CH4, and so on. Additional, based on the digital of experiment andtheory analysis, pyrolysis mechanisms of cellulose, hemicellulose and lignin werestudied and the primary reaction pathways of three components of biomass duringmicrowave pyrolysis were discussed.Comparing to the conventional oil bath pyrolysis, the microwave pyrolysis with[BMIM]Cl as additive but without catalysts could get the maximum oil yield in arelatively short time, the pyrolysis experimental device is more simple and the operationis more convenient. Therefore, as a rapid, efficient and new method to preparation ofbiomass oil, microwave technology is worth further researching. |
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