关键词: 抽提蒸馏, 抽余油, 石油醚生产, 重芳烃, 非芳烃, 苯

Abstract:

The refining structure of SINOPEC Luoyang Company has been adjusted, the liquid-liquid extraction unit has been shut down. The aromatics extraction process was changed from liquid-liquid extraction to extractive distillation, resulting in the quality change of raffinate oil and no longer meeting the requirements of petroleum ether production for feedstocks. In order to resume the production of petroleum ether and improve the quality of the raffinate while ensuring the quality of the extracted oil, the following optimization measures were taken. Optimizing the feed, controlling the heavy fraction content of the top material of the pre fractionator, and reducing the adverse effect of heavy aromatics on solvent selectivity. Increase the operating temperature of solvent recovery tower and reduce the reflux ratio to reduce the aromatic content of circulating solvent. The aromatics content in the raffinate oil decreased significantly when the extraction distillation column was properly cooled. Under the feed load of 49 t/h, the reboiled steam volume decreased by about 2 t/h, the mass fraction of benzene decreased from 0.10% to 0.01%, and the mass fraction of toluene decreased from 0.17% to 0.13%. After optimization, the mass fraction of non aromatic hydrocarbons in the extracted oil increased from 0.01% to 0.04%, and the mass fraction of benzene and total aromatic hydrocarbons in the raffinate oil decreased to less than 0.05% and 0.20% respectively, which not only met the production needs of petroleum ether, but also reduced the energy consumption of the unit and improved the economy of the unit operation.

Key words: extractive distillation, raffinate oil, petroleum ether production, heavy aromatics, non aromatic hydrocarbons, benzene