Fluidized Bed Pyrolysis Of Solid Waste And Research On Liquid And Solid Products

The main research contents of this subject were the basic research of fluidized bed pyrolysis of textile dyeing sludge(DS)and furfural residue(FR).DS and FR were rapidly pyrolyzed by a continuous electric heated fluidized bed and collect pyrolysis chars,condensates.The products distributions and compositions were observed by changing temperature and adding catalysts.The effects of temperature and catalysts on DS,FR pyrolysis were investigated.The chars and condensates obtained by pyrolysis of DS and FR were subjected to be tested and analyzed,the distributions and transformations of nitrogen(N),sulfur(S),chloride(Cl)pollutants in the products during pyrolysis were studied.The main research results are as follows:(1)Fluidized bed pyrolysis(FBP)of DS was carried out in a benchtop unit.As the temperature increased,the yield of DS pyrolysis char(DC)decreased,and the yield of non-condensable gas increased.The addition of kaolin at 850 oC revealed a minimum(73.47 wt%)in DC yield and a maximum non-condensable gas yield(24.10 wt%).The maximum condensate yield(3.52 wt%)was observed at 650? without additives.The catalyst reduced condensate yield and promoted decomposition of macromolecules such as siloxanes and allyl dichloroacetate.The condensate was alkaline and had a water content of more than 92 wt%.As the temperature increased and the catalysts were added,the surface morphology of the DCs were significantly improved.(2)The pyrolysis of FR in a fluidized bed was studied.The solid volume reduction rate reached 61.76 v%.The catalysts significantly reduced the contents of C,H,N,and S in FR pyrolysis char(FC),and promoted the decomposition of organic matter.FTIR spectroscopy indicated the presence of compounds such as alcohols,alkanes,ketones,carboxylic acids,aldehydes,and the like in FC.XRF analysis showed that the main metal elements in FR were K,Fe,Ca,Al and Mg,and the non-metal elements were mainly Si,S,Cl and P.The condensate was acidic and the FR pyrolysis oil(FO)yield reached a maximum value of 2.29 wt%at 750?.The main compounds in FO were found to be ketones,aldehydes and phenols by GC-MS.The total content of oxygenates was as high as 92.36%.(3)During the DS pyrolysis process,the increase in temperature promoted the release of N,S and Cl,kaolin and Ca-bentonite enhanced the release of S,while CaO has good S retention.Some N-containing heteroaromatic ring systems(pyridine)and cleavage volatiles were the primary pathways for the formation of HCN.Hydrolysis of the pyridine derivatives,amino groups and HCN in DC contributed to more NH3 formation.Organic S compounds(thiophene,benzothiophene,and mercaptans)might be sources of H2S during pyrolysis.The formation of HCl may be related to the decomposition of H radicals and organic compounds containing Cl,and may also be formed by the interaction of steam,Cl-containing inorganics and other inorganic substances.During FR pyrolysis,N,S and Cl were mainly present in FC.Kaolin was beneficial to the decomposition and secondary cracking reactions of N-containing compounds in FR.Ca-bentonite and CaO had a certain N retention effect,and CaO had considerable S retention and strong retention capacity of Cl.The XRD analysis of solid products,the GC-MS test of FO and the distribution results of N,S and Cl were used to investigate the mechanism of conversion and release of gas phase N,S and Cl.