Heavy oil cracking: the other leg of the ethylene industry

Ethylene production has become an important indicator of the development of a country's petrochemical industry to some extent. In the development of the ethylene industry in China, the shortage of light hydrocarbon resources is one of the bottlenecks that has plagued the industry for a long time. In order to solve this problem, several domestic heavy oil cracking olefins technologies have been developed in recent years. Many companies in the relatively scarce ethylene region are optimistic about this process technology and want to invest in heavy oil cracking and olefin production projects. When the reporter recently interviewed experts from the China Petroleum and Chemical Industry Planning Institute, he learned that at present, there are still two major problems in the development of domestic crude oil cracking to olefins, and the technology has not yet completed the industrialization and raw material heavy oil supply.

The light oil content of China's crude oil is generally low, and straight-run naphtha and light diesel generally only account for about 30% of crude oil. It is estimated that by 2010, China's ethylene demand will reach about 25.5 million tons, and the output will reach 15 million tons. Based on this calculation, it is estimated that light oil for chemical use will be approximately 60 million tons, and the corresponding refining capacity for crude oil will be approximately 600 million tons. Obviously, it is difficult to meet the development of the downstream petrochemical industry in terms of crude oil resource supply and crude oil processing capacity building.

In order to open up new raw material routes, many research institutes in China have carried out research on heavy oil cracking technology. In 2000, Beijing Petrochemical Research Institute developed catalytic pyrolysis to produce ethylene and propylene technology (CPP). Its characteristic is that heavy oil is used as raw material, specially developed acidic molecular sieve catalyst is adopted, operating conditions are milder than traditional steam cracking ethylene, and it is suitable for direct processing of atmospheric residue oil, especially paraffin base oil, and can also be mixed with appropriate amount of decompression. Residual oil. The technology was industrially tested at Daqing Refining & Chemical Branch from October 2000 to January 2001. The test plant was transformed from a set of 120,000 tons/year deep catalytic cracking industrial equipment. The expert's appraisal and evaluation of the test results is that the technology is mature and the process is reliable. The CPP process is implemented by using an existing catalytic cracker to carry out appropriate transformation. It is a new way to develop petrochemicals based on heavy feedstocks on the basis of catalytic cracking. According to the calibration data, once the device reaches the economic scale, its integrated production cost will be lower than that of the steam cracker.

At the end of 2005, Shenyang Chemical Industry Co., Ltd. adopted CPP technology to start construction of the first domestic 500,000 tons/year catalytic pyrolysis system to produce ethylene and propylene, which is expected to be completed in 2008.

Similar technology is also developed by Luoyang Petrochemical Engineering Company's direct contact cracking of light oil olefins (HCC) technology. The process draws on mature heavy oil catalytic cracking process technology and uses riser reactors or down-tube reactors to achieve high temperature (660~700°C) and short contact time (less than 2 seconds), and it is now in Qiqihar Chemical Industry. The company successfully tested industrial tests. The HCC unit modified by the catalytic cracking unit is the world's first industrialized experimental unit for direct cracking of ethylene into heavy oil, with a processing capacity of 60,000 tons/year and 100% Daqing atmospheric residue. After more than two years of industrial tests, the results show that the yield of olefins cracked by the device is basically consistent with the pilot test data; the industrial products of the catalyst have good cracking activity.

The reporter learned that although heavy oil cracking has been considered by many experts as the other leg of the current domestic B industry, there are still some problems in the development of such projects.

When the reporter recently interviewed experts from the Petrochemical Department of the China Petroleum and Chemical Planning Institute, it was learned that the domestic development of heavy oil cracking and olefins production also needs to address two major issues: First, the technical realization of the industrialization and industrialization of the device to reach production standards and long, safe and stable operation. The first industrialized installation in China, Shenhua's 500,000 tons/year CPP, is still under construction and it will be completed by 2008. It is not advisable to enlarge such devices before the first industrial device is successfully operated. The second is that the domestic commercial transfer of heavy oil cracking to olefins technology is specifically developed for Daqing's paraffin-based heavy oil, and its application to raw materials is relatively narrow. Before the current domestic two major oil companies have a high degree of monopoly on raw material heavy oil resources, the company’s heavy oil cracking projects are at high risk. Lubei Group began investing 700 million yuan in the construction of a heavy oil cracker at the end of 2002. By August 2003, it stopped construction due to raw material heavy oil and other reasons. According to the company’s financial statements in the first quarter of this year, the company’s The $170 million invested has not benefited.

Due to the shortage of crude oil resources in China, whether it is from the increase of ethylene production or the use of good oil resources, the process of heavy oil cracking and olefin production can broaden the sources of olefins for production, which is more in line with the actual situation of China's oil resource endowments. However, this "leg" must really go quickly and steadily. Obviously, it must be practiced.