Abstract: Taking the integrated enterprise with the small refining capacity and large ethylene capacity as an example, starting from the overall refining process, the main reasons for poorrefining profitability arelack of optimization of heavy oil processing route, low processing capacity of catalytic reforming and catalytic cracking units, high processing capacity of coking unit, and high cost of hydrogen production from natural gas. A two-step approach for oil refining transformation and upgrading is proposed, and the effectiveness and shortcomings of residue catalytic cracking in refinery transformation and upgrading are discussed. On this basis, using the whole process model of refining and ethylene plants,the necessity is discussed to construct a medium pressure hydrogenation and upgrading unit for straight run dieseland a continuous catalytic reforming unit, and a comparison is made between the construction of a solvent deasphalting unit and a fixed bed heavy oil hydrogenation unit, so as to provide ideas and directions for the further development of enterprises.

Key words: refining, transformation and upgrading, heavy oil processing route, optimization, ethylene raw material