Study On Process For Blending Coker Gas Oil In FCCU

With the increase of domestic demand for fuel oil and chemical products, the use of Coker gas oil increases year by year.However, Coker gas oil contain high content of nitrogen compounds. High basic nitrogen content means the poisoning of FCC catalyst, which will affect the whole process of catalytic cracking reaction.Coker gas oil provided by Jingbo company has more basic nitrogen, aromatic hydrocarbon and resins than VGO provided by Huangdao refinery. According to results of the different Coker gas oil blending ratio experiment, we found that with the increase of the ratio of Coker gas oil the conversion and the yield of light oil are reduced, the yield of dry gas and coke are increased.Increasing the reaction temperature will weaken the catalyst poisoning effect by basic nitrogen. When we increase temperature from 480℃ to 500℃, the yield of LPG and gasoline increase nearly 3.5 and 3 percent, the yield of dry gas also increase because of the increase of proportion of thermal cracking reaction. Increasing the catalyst/oil ratio can improve the conversion rate of the reaction,reducing the adverse impacts by basic nitrogen compounds in Coker gas oil on the process. However increasing catalyst/oil ratio simply will also cause the increase of the yield of coke. If we increase the mixing temperature at the same time, the increase of the yield of coke becomes less obvious. Extending residence time suitably is favorable for catalytic cracking reaction of Coker gas oil.We use the catalyst reacted with VGO to adsorb the basic nitrogen compounds in Coker gas oil. And we found that the blending ratio of the Coker gas oil and the amount of coke on the catalyst will affect the adsorption effect. In the experiment of combination feeding, we inject the VGO from the bottom of the riser and Coker gas oil from the middle injection. We collect the heavy oil and inject it into the riser again. Compared with the conventional processing method, the conversion rate increase nearly 2.7%. The yield of dry gas and coke increase slightly. Although the yield of LPG decline slightly, the yield of gasoline and diesel increase significantly.