PROCESS FOR DEEPLY DESULFURIZING CATALYTIC CRACKING GASOLINE

摘要

The present invention provides a process for desulfurizing gasoline fraction by solvent extraction: introducing the gasoline fraction into an extraction tower at a lower-middle part thereof, introducing a solvent into the extraction tower at the top thereof, injecting saturated C5 hydrocarbon into a reflux device at the bottom of the extraction tower, wherein the temperature at the top of the extraction tower is controlled between 55~100°C, the temperature at the bottom of the extraction tower is controlled between 40~80°C, and the pressure at the top of the extraction tower is controlled between 0.2~0.7MPa, a feeding ratio of the solvent to the gasoline fraction is controlled between 1.0~5.0, and a feeding ratio of the saturated C5 hydrocarbon to the gasoline fraction is controlled between 0.1~0.5, and wherein the gasoline fraction which is desulfurized by extraction flows out from the top of the extraction tower, and washed with water, to obtain a desulfurized gasoline fraction; the solvent that has extracted sulfide, aromatics and C5 hydrocarbon flows out from the bottom of the extraction tower, and is separated into a C5 hydrocarbon-containing light component, a sulfur-rich component, water and the solvent, wherein the light component is returned to the reflux device of the extraction tower, the water is returned to the washing step, and the solvent is returned to the top of the extraction tower. The present invention also provides a process for deeply desulfurizing catalytic cracking gasoline, which flexibly combines the process described above and an existing desulfurization technology, achieving deep desulfurization and significant reduction of the octane number loss of gasoline fraction.