Regulation Of Co-pyrolysis Characteristics And Synergistic Effects Of Additives CaO/Fe₂O₃ On Livestock And Poultry Wastes And Coal

Coal pyrolysis is an important way of efficient utilization of coal resources and one of the key techn ologies to produce high value-added oil products.However,due to the relatively low hydrogen and carbo n content of coal and the high content of heavy components in pyrolysis tar,it will not only cause the blo ckage of pipelines,but also cause certain corrosion.Livestock and poultry waste,as a kind of low value b iomass with high hydrogen to carbon ratio,often need incineration and accumulation treatment,not only pollute the environment,but also cause resource waste.The co-pyrolysis of coal and livestock wastes ca n not only reduce the content of heavy tar by taking advantage of the high hydrogen-carbon ratio of lives tock wastes,but also realize the clean utilization of livestock wastes as harmless resources.However,due to the difference of pyrolysis temperature interval between livestock and poultry waste and coal,the int eraction strength between livestock and poultry waste and coal is weak in the process of co-pyrolysis.Th erefore,how to improve the interaction strength of the two in the process of co-pyrolysis is of great signi ficance for the realization of clean resource utilization of the two.Using Meihuajing coal and cow dung a s raw materials,calcium oxide and iron oxide as additives,the regulation mechanism of additives on the synergic effect of coal and cow dung during co-pyrolysis was studied by pyrolysis gas chromatographymass spectrometry system.The main research contents and conclusions are as follows:The effects of the type and amount of iron oxide on the co-pyrolysis characteristics and synergies o f coal and cow dung were studied by pyrolysis chromatography-mass spectrometry system and thermogr avimeter.The results show that compared with commercial ferric oxide and nitric acid cracking ferric oxi de,ferric oxide(E-Fe2O3)prepared by precipitation method has better catalytic and regulatory properties for co-pyrolysis.The addition of E-Fe2O3 not only reduces the pyrolysis temperature of coal but also del ays the release of volatiles during cow dung pyrolysis,enlarging the overlap interval of pyrolysis temper ature of coal and cow dung during co-pyrolysis,significantly enhancing the synergistic effect of the two,promoting the release of volatiles and improving the conversion and utilization efficiency of coal and co w dung.With the increase of E-Fe2O3,the synergistic effect between coal and cow dung was obviously e nhanced.In addition,the addition of E-Fe2O3 limits the formation of ketones and phenols during co-pyro lysis and promotes the formation of hydrocarbons,thus improving the tar quality.Using calcium oxide as additive,the effects of different calcium oxide addition ratio and rapid pyro lysis rate on the composition and content of in-situ tar during co-pyrolysis of coal and cow dung were st udied.The results show that the influence of CaO on the interaction between CD and MHJ is different in different temperature ranges,and is affected by the amount of CaO.CaO has a positive synergistic effect on the formation of hydrocarbon compounds at 350～450℃ and oxygen-containing compounds at 450～550℃.At 50～450℃,the content of olefins and alkanes in tar increased with the increase of CaO,but at 550～850℃,excessive CaO hindered the formation of these compounds.In addition,the influence of CDMHJ interaction on tar composition varies with the temperature range and the amount of CaO.The effects of calcium oxide and E-Fe2O3 on co-pyrolysis of coal and cow dung and their synergisti c effects were studied.The results show that the synergistic effect of E-Fe2O3/CaO on the co-pyrolysis of coal and cow dung is stronger than that of E-Fe2O3,which is due to the dual regulation of calcium oxide and E-Fe2O3 on the pyrolysis interval of coal and cow dung.However,the high Fe2O3/CaO composite ad ditive ratio is not conducive to the improvement of the synergistic effect between coal and cow dung dur ing the co-pyrolysis process.Compared with the single additive,the content of oxygen in tar during co-p yrolysis of coal and livestock waste is lower with the addition of compound additive,The content of hyd rocarbons is lower than that of E-Fe2O3 catalyst with a ratio of 0.4.