Study on the preconcentration technology of naphthalene aromatics in ethylene tar

Based on deep research of the basic properties and compositions of the by-product ethylene tar from ethylene cracking unit, a new highly efficient preconcentration technology of naphthalene aromatics in ethylene tar was developed. A high selective extractant R was prepared to achieve high-efficiency preconcentration of high value-added biocyclic naphthalene aromatic components (such as naphthalene, α-methylnaphthalene, β-methylnaphthalene) under mild conditions. Under the optimum extraction conditions, the yield of extracted oil is 55.46%, the extraction recovery of naphthalene, β-methylnaphthalene and α-methylnaphthalene is 96%, 93% and 91%, respectively. Compared with the direct distillation of ethylene tar, handling capacity of raw material for subsequent distillation cutting process is reduced substantially. The active components which are easy to polymerize and scale can be removed by extraction.Accordingly, the equipment is not easy to be blocked due to scaling, and the operation cycle is prolonged. Moreover, the extraction process makes the oil more lighter, reduces the severity of the distillation unit and the separation difficulty of each component in the later distillation, and improves the product quality.