The Research On Co-liquefaction Of High Density Polyethylene And Biomass

In recent years, with the fossil fuel exhausting, the research of bio-energy is getting more and more attention. Liquefying biomass to acquire bio-oil is the hotspot of research area. Biomass is rich and distributes widely, combusting biomass will not produce noxious gas, so the exploitation of bio-energy becomes popular. Along with widely use of plastic and increasingly mature liquefaction technology, the liquefaction technology of plastic emerges, plastic has good liquefaction quality, it is rich in carbon and hydrogen, and the H/C is close to the H/C of petroleum in the contrast of coal. At the present time, the liquefaction of plastic alone needs high energy consumption and the yield of oil is low, seeking better way of liquefaction is the focus of today's research. Co-liquefaction of plastic and biomass has gradually been put on the agenda.This study used the de-ionized water as reaction medium, and plastic (the high density polyethylene) and sawdust as raw material to do the investigative test, inspecting the reaction characteristic of co-liquefaction under different reaction conditions. These experiments were carried out in a batched high-pressure autoclave with 1L volume on the conditions that the temperature is between 613K and 693K and the press is 20-30MPa, inspecting the reaction time, temperature and solvent fill rate on co-liquefaction, the catalyst is the emphasis. The result of experiments without catalysts showes that the addition of sawdust can reduce the demand of high temperature of liquefaction of plastic, co-liquefaction will gain higher oil yield. Under the temperature of 653K, the highest oil yield is 24.0% and the convention is 83.5%, the heat value of the oil is 44.6MJ/kg. At the same time, under the better co-liquefaction reaction conditions of high density polyethylene (HDPE) and sawdust , the co-liquefaction experiments of high density polyethylene and sunflower seeds, and the co-liquefaction experiments of high density polyethylene and peanut shell were carried out, the result showes that without catalysts sunflower seeds and peanut shell with high C element content and H element content display better liquefaction quality than sawdust, oil-yield and convention are both higher than co-liquefaction of high density polyethylene and sawdust, the result explaines that high C element content and H element content is in favor of co-liquefaction of high density polyethylene and biomass. On catalytic experiments, we researched the catalyst's influence on results of co-liquefaction of high density polyethylene and biomass. The experiments choosed the sawdust as the delegate of biomass. The result indicates that zeolitic catalyst (HZSM-5) showes benign catalytic activities in the selected catalysts. Under the same reaction conditions the max oil yield is 24.0% of co-liquefaction of high density polyethylene and sawdust without catalysts, but after the use of zeolitic catalyst, the oil yield increases to 54%. Base catalyst NaOH and metallic catalyst molybdenum powder also show preferable catalytic activities. The researches show that some catalysts can advantage the results the co-liquefaction of high density polyethylene and biomass. But the catalysts which refered above are not so good when the biomass are sunflower seeds and peanut shell, which indicates that the catalytic activities of catalyst can be influenced by biomass kind, different biomass need different catalyst.The heat value analyse and GC-MS analyse of oil we got show that the heat vlue of our oil is high, the oil is rich in the C and H, and the combustion value is high.This article researches show that co-liquefacting high density polyethylene and biomass to produce bio-oil which similar to petroleum is a feasible way of developing new energy, the bio-oil is clean and reproducible, this new research makes sense of easing the current situation of energy crisis and has great potential which is worth of intensive study..