Basic Research On Microcrystalline Wax Production Process By Solvent Dewazing

Abstract:With the development of solvent dewaxing technology and the environmental protection, factory MEK-TOL dewaxing unit is moving using the same solvent composition and ratio for light and heavy dewaxing raw, single solvent replacing mixed solvents and less power direction. The diversity of microcrystalline wax' structure can lead to different in service performance. In order to select microcrystalline wax reasonably, it is the urgent to research the structure of microcrystalline wax from vacuum residue and heavy fraction oil.The solvent dewaxing research on production of microcrystalline wax with MEK-TOL solvents by multiple dilution and primary dilution from light deasphalted refined oil and vacuum cut forth refined oil as raw materials were studied in this paper. The solvent composition and ratio were same. Taking the yield and oil content as assessment indexes, the effect of dewaxing by multiple dilution and primary dilution were discussed. MIBK,DCM,EDC,MAC,EAC and MEK-TOL solvents were used as dewaxing solvents for the two raw oils, whose dewaxing effect were also compared. The structure of microcrystalline wax of light deasphalted refined oil and its microcrystalline wax, vacuum cut 4 refined oil and its microcrystalline wax was determined by GPC, FTIR,1H-NMR and CHN analyzer. And their average structure parameters were calculated by improved Brown-Ladner method. The results showed that under the same solvent composition and ratio, compared with the oil content of microcrystalline wax from factory and the different raw oils, the fall of oil content was almost same. The oil content of microcrystalline wax of multiple dilution was lower than that of primary dilution; however, the yield was less than that of primary dilution method. In addition, MIBK was the best single dewaxing solvent. Single solvent MIBK could be considered as light deasphalted refined oil dewaxing solvent. The smaller average molecular weight was, the more oil content had and small aromatic structures of light deasphalted and vacuum cut 4 refined oils were removed by dewaxing process. The more the content of NCH2/NCH3 was,the drop melting point of microcrystalline wax would have. The molecular structure of light deasphalted microcrystalline wax can be regard as cycloalkanes with 1 or 2 rings and various long alkyl chains. For the vacuum cut forth refined oil, there are almost no aromatic hydrocarbons. The molecular structure of vacuum cut 4 microcrystalline wax can be regard as long chain.