Study On Co-pyrolysis/incineration Thermal Disposal Characteristics Of Two Kinds Of Waste Tires Of Shared Bicycles And Textile Dyeing Sludge

Waste tires of shared bicycles,known as"black pollution",are one of the major solid waste threats facing the world.They are characterized by high volatile content,low ash content and high calorific value.They are mainly divided into rubber and polyurethane materials.The components of textile dyeing sludge（TDS）are complex and diverse,including dyes,additives,flocculants,polycyclic aromatic hydrocarbons（PAHs）,persistent organic pollutants（POPs）,heavy metals and other toxic and harmful substances.The correct disposal of the two kinds of waste is the key factor related to cleaner production.Co-pyrolysis/incineration of waste tires and TDS can make up for the shortcomings of the two materials.Rubber tire（RT）/polyurethane tire（PUT）and TDS were selected as the research objects,and the decomposition behavior of single sample and mixed sample was discussed in the nitrogen/air atmosphere.The thermogradimetric decomposition behavior,thermodynamic and kinetic parameters of different temperature,atmosphere and mixing ratio conditions were discussed.Effects of pyrolysis product distribution and migration,transformation and residue of heavy metals in slag.The main conclusions are as follows:（1）TG,TG-FTIR and Py-GC/MS were used to investigate the pyrolysis behavior,products,kinetics and thermodynamics,and reaction mechanism of RT and PUT.RT is divided into the decomposition stage of rubber and further decomposition of products at high temperature,PUT is divided into the decomposition stage of carbamate and polyols and isocyanates.Py-GC/MS results showed that the main pyrolysis products of RT were isoprene,D-limonene and styrene,while that of PUT was 2-hexene and diaminodiphenylmethane.Kinetic analysis shows that the E of PUT is lower than RT.The main devolatilization models of the two tires were fitted in different stages by using the master graph method.The best fitting models of RT in three stages were D2,F2 and F2.The best fitting models for the three stages of PUT are F1.5,F1 and F2.（2）TG-FTIR,TG-MS,2D-COS,Py-GC/MS and FTIR methods were used to analyze the co-pyrolysis products of RT/PUT and TDS.When the mixing ratio is 1:1,the thermogravimetric behavior,interaction and CPI all reach the best results.The synergistic effect of co-pyrolysis with PUT was stronger than that of RT incorporation.The co-pyrolysis reduced emissions of CO₂,CO,SO₂,and nitrous compounds,and produced more hydrocarbon products.The TR co-pyrolysis produced more D-limonene and isoprene and inhibited the isomerization of D-limonene.The TP co-pyrolysis further decomposed diaminodiphenylmethane into low-molecular weight benzene series such as toluene and styrene.The co-pyrolytic chars had higher branching degree of aliphatic side chain and bridge bond,with the TP ones having the enhanced char aromaticity.（3）TG-FTIR,XRF,XRD and thermodynamic equilibrium simulation methods were used to analyze the co-combustion behavior and products of RT/PUT and TDS.The increasing of heating rate will increase the values of₄),₍（7） andT25R75 and T25P75 have the best combustion performance,and the performance of TP is better than TR.Co-combustion reduces the activation required for the reaction.There are differences in the optimal mechanism function models at the same stage,but there are little differences in the major reaction mechanisms.The production of C-H increases,reducing the emission of SO₂,and the emission of NO in TP will advance.Co-combustion is beneficial to reduce the viscosity of residues,promote the further combustion of substances,and improve the scale and sintering situation.XRD results show that the composition of T25R75-1000 and T25P75-1000 consists of Ca SO₄,Ca₂Si O₄,Ca Fe₂Fe OHOSi₂O₇,Fe₂O₃ and Ca Si O₃.Fact Sage simulation results show that T25R75-1000 also has Fe-Ca crystallization products and Ca SO₄,in addition to Ca CO₃.The results of T25P75-1000 simulation are consistent with XRD,and Fe₂O₃ is also its main crystallization product.（4）The co-pyrolysis and incineration experiments of RT/PUT and TDS were simulated in a tubular furnace,and the contents and transformation characteristics of seven heavy metals under different reaction atmospheres（air and N₂）,temperatures（650,750,850 and 950℃）and material conditions were investigated by microwave digestion/ICP-OES and SBR.The fixation ability of As was TR>TP>TDS.The fixation effect of Pb and Cd in air combustion is obviously stronger than that in pyrolysis.The fixation effect of Pb and Cd is most affected by temperature.TR under combustion and pyrolysis can reduce the proportion of As residue.Adding waste tire can improve the environmental risk of Cu,Mn and Ni.Cu and Pb have stronger predominance under N₂,while Mn and Ni have lower risk and harm under air combustion.Heat treatment conditions in air and N₂ did not reduce the environmental harm of Cd,but also had great ecological toxicity.