Abstract: According to the process characteristics of DCC-plus unit, in order to increase economic benefits and widen the source of feed for DCC-plus unit, based on the laboratory evaluation results of cracking performance of light deasphalted oil, a company has developed a new type of DCC-plus unit, and the optimum blending mass ratio of no more than 20% was determined. According to the company's production and operation deployment, the company started blending light deasphalted oil into the mixed feed of DCC-plus unit from May 2022. In view of the deterioration of the properties of the mixed raw materials after blending light deasphalted oil, the effects on the product distribution, product properties, operating parameters, catalysts, energy consumption and flue gas pollutant concentration of the DCC-plus unit after blending light deasphalted oil were analyzed. At the same time, the corresponding countermeasures were put forward, which not only ensured the smooth operation of the DCC-plus unit, but also obtained better economic benefits. The CDU could reduce the processing amount of high-priced paraffinic-base crude oil, and obtained 540 CNY/t (for light deasphalted oil) benefit，with an annual benefit of 190 million CNY.

Key words: light deasphalted oil, blending, DCC-plus unit, deep catalytic cracking, economic benefit