By Ren Yunfeng, Chemical Industry and Engineering Society of China

“Refining-chemical integration” refers to the production integration of refining and naphtha cracking. This model can make full use of petroleum resources, reduce energy consumption and production costs, and thereby greatly strengthen the producers’ anti-risk ability. The added value of crude oil processing products from such integrated plants can be increased by about 25%. Meanwhile, the costs of water supply, power supply, energy conservation and environmental protection, and safety utilities can be saved by more than 10%, and the energy-saving and emission reduction effect can be increased by about 15%.

   The integration of refining and chemical can maximize economic and environmental benefits. It is the development trend of the petrochemical industries and the leading direction of China’s petrochemical industry during the 13th Five-Year Plan.

Diversified investment market and centralized project bases

   In recent years, the private integrated refining and chemical projects have developed rapidly. An integrated and diversified market structure consisting of state-owned enterprises, private enterprises, teapot refineries, and joint ventures has gradually formed.

   A number of large-scale domestic refining and chemical enterprises have concentrated in China's Bohai Rim region, Hangzhou Bay area, and Huizhou Daya Bay. The Petrochemical Industry Planning and Layout Plan formulated by the National Development and Reform Commission proposes to promote the development of industrial clusters and build seven major petrochemical bases in Shanghai, Ningbo, Huizhou, Gulei, Changxing Island, Caofeidian, and Lianyungang. It is expected that by 2025, the refining capacity of these seven petrochemical bases will account for 40% of the country's total capacity. The average refining scale of a single refinery will be between 15 million and 20 million tons.

Flexibility and deepening of technological innovation

   With the deep integration and development of refining and chemical technology, a series of integrated refining and chemical processes have been formed, including multi-product technologies, (such as multi-product naphtha technology, multi-aromatic hydrocarbon technology, multi-product low-carbon olefins technology); energy-saving integrated technologies, (such as the separation of C2 as ethylene feedstock technology in dry gas and the technology of disproportionation of ethylene and C4 olefins in FCC dry gas to generate propylene); refining and integrated production optimization combination technology; and alternative new technologies.

   1. Technologies to increase the feedstock of ethylene and aromatic 

   There are many ways to increase the output of ethylene and aromatics feedstocks in the refining process: 1) increasing naphtha output by using hydrocracking technology; 2) increasing the output of ethylene’s feedstock tail oil by medium pressure hydrocracking technology; 3) producing more coke naphtha via delayed coking technology; 4) adding the production of reformer feed via the combination of catalytic cracking of heavy gasoline and hydrofining; 5) producing more liquefied petroleum gas. 

   2. Technologies to expand the production of low-carbon olefins

   Technologies increasing the production of low-carbon olefins are as follows: 1) increasing propylene by catalytic cracking technology; 2) increasing C3 by disproportionation process; 3) increasing propylene and olefins by C3 conversion technology.

   3. Technologies to increase the output of aromatics

   The aromatics increasing technologies during the oil refining process are: 1) extraction distillation technology; 2) reforming technology; 3) C8 isomerization technology; 4) toluene disproportionation and transalkylation technology.

   4. Integrated technologies

   They include the integrated technology of refining and ethylene production with high yield of cracking materials, and the naphtha-saving hydrogen chain combination technology of refining-chemical fertilizer integration. In addition, the refinery has further developed the integration of refining-aromatics, integration of refining-ethylene-aromatics, and integration of refining-power generation-steam on the back of the need for hydrogen, the need for the cogeneration of gas power and thermal electricity, and the growing demand for electricity as a secondary energy source in the future. 

   5. New technologies

   In addition to the upgrading of traditional refining and chemical integration technologies and the development and optimization of catalysts and processes, some new technologies have also emerged in recent years: 1) direct cracking of crude oil to olefins, which can eliminate the main oil refining links such as atmospheric and vacuum distillation and catalytic cracking to maximize the production of olefins and aromatics with the chemical conversion rate from 50% to 70%; 2) natural gas to olefin/aromatics, which, compared with the existing traditional route, does not require a high energy-consuming synthesis gas preparation process, and the carbon atom utilization efficiency can reach 100%.

Be alert to the shift of capacity excess

   Refined oil, which is the main product of crude oil processing, has been facing severe excess pressure in recent years. According to the "2019 China Energy and Chemical Industry Development Report" issued by the China Petroleum and Chemical Corporation's Institute of Economics and Technology, it is estimated that domestic refined oil production in 2019 will be 371 million tons, while the apparent consumption will only be 323 million tons. In contrast, there are large supply gaps in many basic chemical raw materials, especially the basic organic chemical raw materials such as ethylene, propylene, and aromatics. The demand for chemical products, especially high-end chemical products, has increased. The state requires that new refining projects are constructed in accordance with the integrated refining and chemical configuration, requires strict control of new refining capacity and promotion of the elimination of backward and inefficient refining capacity, and encourages enterprises to vigorously develop new chemical materials and special chemicals. The statistics of China's refining-chemical integrated projects in 2019 are shown in Table 1. 

   Table 1  China’s refining-chemical integration projects in 2019

   The transformation of refining and chemical enterprises from the large-scale production of refined oil and bulk petrochemical raw materials to the production of high value-added oil products and high-quality petrochemical raw materials will inevitably shift the pressure of excess oil refining capacity to the chemical sector. It is necessary to be alert to the excess capacity of the chemical sector.