| Pyrolysis is an important technology for achieving the recycling utilization of municipal solid waste.The treatment,disposal and recycling utilization of tar,as one of the three-phase products of municipal solid waste pyrolysis,have great significance for the popularization and application of pyrolysis.In recent years.In recent years,more and more attention has been paid to it.However,there is still little research on the disposal and recycling utilization of municipal solid waste pyrolysis tar,which affects the application of pyrolysis technology to some extent.The article focused on pyrolysis tar from municipal solid waste,studied its physicochemical properties and chemical composition,and researched its emulsification process in diesel.The feasibility of emulsified oil as fuel oil was investigated,which provided reference for the treatment and recycling utilization of tar.By experimental studies,the following conclusions have been drawn:(1)The density of pyrolysis oil of municipal solid waste was 1.247g/cm~3,and the kinematic viscosity was 11.81mm~2/s,both was higher than that of general fuel oil.The pH was 2.65,showing strong acidity.The tar collected during the experiment had very little moisture.The low calorific value of tar is 28.95 MJ/kg,which has great potential as a fuel oil.The C element is the main component of tar.And the O content of tar is relatively high,reaching 21.05%.Deoxidization of tar need to be paid attention in upgrading and utilization.The content of H in tar is 6.34%,and the content of N and S is small.(2)The chemical components of tar mainly include alkenes,alkanes,alcohols,acids,aldehydes,esters,ketones,phenols,nitriles,amines,monocyclic aromatic hydrocarbons,polycyclic aromatic hydrocarbons and other heterocyclic compounds.Tar contains a large amount of acids and esters,reaching 27.86%and 25.34%respectively.Phenols account for a large proportion of oxygenated organics,while alcohols,aldehydes,and ketones are relatively less.There are also nitrogenous organic compounds,such as nitriles and amines produced by protein cleavage.Among the hydrocarbons,macromolecules of polycyclic aromatic hydrocarbons account for a relatively large proportion;naphthalene,anthracene,phenanthrene,and derivatives thereof occupy a large proportion in the PAHs.(3)The single factor test of tar and diesel emulsification showed that both the stability and the pH of the emulsified oil increased first and then decreased with the increase of the hydrophilic-lipophilic balance(HLB),and the viscosity increased with the increase of the HLB value.With the increase of the amount of emulsifier,the stability of the emulsified oil gradually increased,and the acidity gradually weakened,but the viscosity gradually increased.The greater the amount of tar added,the greater the viscosity and the lower the pH of the emulsified oil,the worse the stability.When the temperature is below 40°C,the stability of the emulsion does not change significantly with increasing temperature,and the emulsified oil has the lowest viscosity and the weakest acidity at 40°C.After that,as the temperature increases,the stability of the emulsified oil gradually deteriorates.(4)Through the orthogonal test,the optimal process conditions for emulsification of tar and diesel oil are as follows:HLB value of compound emulsifier at 8,emulsifier usage at 12.5%of diesel volume,tar addition at 4%of diesel volume,emulsification temperature at 40°C.(5)The emulsified oil obtained under the optimum emulsification process conditions has a transmittance of 0.967,good stability.Density and kinematic viscosity are lower than pyrolysis tar and slightly higher than diesel.Thermal value is42.83MJ/kg.Copper Corrosion test results show less corrosion.(6)Thermogravimetric analysis of tar oil,diesel oil,and the best emulsified oil showed that the weight loss characteristics of the emulsified oil were greatly improved compared to the pyrolysis tar,the overall mass loss rate of the emulsified oil was increased,and the pyrolysis curve shifted toward the low temperature range.(7)The cost of the emulsified oil under the optimum emulsifying conditions is7.95 yuan/L,which is 21%higher than the price of the commercially available 0#diesel,and there is still room for improvement in economic efficiency. |
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