Desulfurization and denitration of light oil by extraction

摘要

This process for the desulfurization and denitration of light oil is effected by extraction with an organic solvent containing nitrogen. The invention also relates to light oil desulfurized and denitrated by said process as well as an organic solvent containing nitrogen for the extraction. The solvent is selected from among, for example, hetrocyclic compounds containing nitrogen, such as pyrrolidones, imidazolidinones, pyrimidinones and pyridinium salts, and acid amides. The combination of the process of this invention with any ordinary process for hydrodesulfurization enables the production of light oil having a sulfur content not exceeding 0.01% by weight. Light oil still containing benzothiophenone and dibenzothiophenone derivatives after hydrodesulfurization can be easily desulfurized to yield a desulfurized product not having any undesirable color, or any offensive smell. Also, the extraction of nitrogen compounds and aromatic compound from light oil is effected by the same process. As the re-extraction of sulfur compounds from the extracted phase or the separation of the extracted phase into the solvent and the extracted oil can be easily carried out, the solvent is reusable. The light oil treated according to the process of this invention enables a reduction of particulates in the combustion product thereof, and has a high cetane index.