Experimental Study On Microwave Pyrolysis Characteristics Of Water Hyacinth

Water hyacinth is a kind of aquatic biomass with strong adaptability to the environment.Its growth rate is extremely fast.The treatment and disposal of water hyacinth have become an important protection issue.Its higher content of hydrogen-carbon ratio provides cheap hydrogen source.Microwave pyrolysis may be one of the effective ways to convert water hyacinth into cheap energy and high value-added fine chemicals.In this study,the microwave pyrolysis of water hyacinth was investigated using a mono-layer quartz reactor,and the pyrolysis products were characterized and analyzed by GC-MS,GC,FT-IR,EA,SEM and XRD.The experimental results of microwave pyrolysis of water hyacinth showed the pyrolysis temperature have influence on the total yield of bio-oil and gas.The yield of bio-oil and bio-gas both increased as the pyrolysis temperature increased.The yield of bio-oil reached its maximum value when the pyrolysis temperature was at 600? and the char yield decreased as the pyrolysis temperature increased.The intensity of absorption peaks of functional groups?e.g.-C =C,-OH,-CH,etc.?in pyrolytic char decreased significantly as pyrolyzed temperature increased.There were more monocyclic aromatic compounds and alcohols in the bio-oil,and the content of mono-cyclic aromatic compounds were higher.The main components of pyrolysis gas were H₂ and CO.The heating rate has a significant effect on the distribution of pyrolysis products of water hyacinth.The increase in heating led to an increase in char yield and a decrease in the yield of bio-oil.However,the yield gaseous products remained relatively unchanged.The accelerated heating rate promotes the decomposition of phenol and its derivatives into straight chain hydrocarbons and the formation of CO in gaseous products.The used of Fe₃O₄ and AC affected the pyrolysis products of water hyacinth.Fe₃O₄ as absorbing agent resulted in lower char yield compared to AC.When Fe₃O₄ is used,the yield of bio-oil increases with the increase of pyrolysis temperature,When AC was used,the yield of bio-oil increased first and then decreased.When Fe₃O₄ and AC are used as absorbing agents,the gas yield,especially that of H₂,can be significantly increased.When Fe₃O₄ and AC were used as absorbing agents,the content of alcohol and straight chain hydrocarbon in the bio-oil increased.When the Fe₃O₄ ratio is increased,the yield of pyrolytic char decreased.However,the yield of bio-oil did not changed,resulting in higher gaseous products,which led to a significantly higher yield of syngas.The use of Fe₃O₄ favoredthe generation of phenols and syngas.