| In this thesis,the solid-liquid equilibria of paraffin in a-pinene,dimethyl carbonate,butanone and toluene were studied,which offered solid-liquid equilibrium thermodynamic basic data for solvent dewaxing process.The study was introduced in the following.Firstly,the solid-liquid data of paraffin in a-pinene,dimethyl carbonate,butanone and toluene were measured by the laser montoring system in the temperature ranging from 283K to 321K at atmostheric pressure.The results showed that the solubilities of paraffin in the selected solvents increased with increasing of temperature.The solubilities of paraffin in four solvents in the order were:a-pinene>toluene>butanone>DMC.The solubilities of paraffin in toluene were similar to DMC.The solubilities of paraffin in DMC were similar to butanone.Secondly,experimental solubility data was correlated by means of Wilson equation,NRTL equation,?h equation and two-parameters,three-parameters of simplified model equations.The average errors of each model with ?-pinene were 6.34%,11.49%,0.53%,1.05%,0.50%,respectively.The average errors of each model with DMC were 81.53%,236.72%,2.11%,2.22%and 2.13%,respectively.The average errors of each model with butanone were 9.40%,12.96%,2.76%,1.28%,1.05%,respectively.The average errors of each model with toluene were 0.61%,2.04%,0.71%,0.79%,0.59%,respectively.The results showed that ?h equation,two-parameters equation,three-parameters equation,Wilson equation were suitable and NRTL equation were not suitable for description of the solubility data of paraffin with a-pinene.The ?h equation,two-parameters equation,three-parameters equation were suitable and Wilson equation,NRTL equation were not suitable for description of the solubility data of paraffin with DMC.The ?h equation,two-parameters equation,three-parameters equation were suitable than Wilson equation and NRTL equation with butanone.Five models were suitable for description of the solubility data of paraffin with ?-pinene.Thirdly,studied the solvent dewaxing with DMC-toluene.The influent factors in solvent dewaxing were investigated by single-factor and orthogonal method.The optimum preparation process was:dewaxing temperature was 5.0?,the mass ratio of composition was 7:3,dilution ratio was 5:1.The yield of paraffin was 53.2%with the optimum preparation process.Fourthly,studied the solvent dewaxing with DMC-?-pinene.The influent factors in solvent dewaxing were investigated by single-factor and orthogonal method.The optimum preparation process was:dewaxing temperature was 2.5?,the mass ratio of composition was 3:7,dilution ratio was 5:1.The yield of paraffin was 48.0%with the optimum preparation process.Fifth,studied the solvent dewaxing with butanone-toluene.The influent factors in solvent dewaxing were investigated by single-factor and orthogonal method.The optimum preparation process was:dewaxing temperature was 5.0?,the mass ratio of composition was 6:4,dilution ratio was 3:1.The yield of paraffin was 42.6%with the optimum preparation process.By comparison of the three dewaxing experiments,the results showed that DMC-toluene and DMC-a-pinene as dewaxing solvents were feasible. |
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