【Ten Years of Rapid Development in Chemical Equipment】1638–2021: China’s first gas cracking furnace with the highest capacity and dual furnaces put into operation

Sinopec Refining & Chemical’s H-007 pyrolyzer is a CBL-R type gas pyrolyzer that utilizes patented technology from Sinopec. Using ethane, LPG, and naphtha as raw materials, its maximum production capacity is 300,000 tons of ethylene per year from ethane; the capacity for pyrolyzing LPG and naphtha is 250,000 tons of ethylene per year and 200,000 tons of ethylene per year respectively, with an annual operating time of 8,000 hours. This pyrolysis furnace was designed using Sinopec’s patented technologies and new technologies for which invention patents have been granted both domestically and internationally. The process package was developed jointly by SEI, Beijing Institute of Chemical Technology, and Tianhua Nanjing Research Institute, with SEI taking overall responsibility for the project. This pyrolysis furnace features a structure with two furnaces and a single convection section (one of the furnaces is used for pyrolyzing naphtha), a dumbbell-shaped conventional quenching heat exchanger equipped with 2-1-1-1 type furnace tubes having large bends at the bottom (one of the furnaces utilizes two-stage quenching), a burner that provides full-bottom heating to minimize nitrogen oxide (NOx) emissions, and a technology that recirculates coking gas back into the furnace. It offers advantages such as flexible operation and high availability, low NOx emissions, a high proportion of domestically produced components (the quenching heat exchangers and burners are all manufactured in China), as well as energy efficiency and environmental protection. Split-chamber pyrolysis and split-chamber coking operations are possible, enhancing the operational flexibility of the ethylene plant. After feeding the material, the flue gas temperature in the pyrolysis furnace is around 100°C, with a thermal efficiency of about 95%. The exit temperature of the rapid cooling heat exchanger is around 340°C, while the exit temperature of the secondary rapid cooling heat exchanger is approximately 210°C. All these parameters meet or exceed the design specifications, placing the system at an internationally leading level. This is China’s first 300,000-ton-class CBL gas feedstock cracking furnace built using proprietary patented technology; it was included in Sinopec’s group company development projects for 2017. Its successful implementation represents a new breakthrough in the enlargement, serialization, and environmental friendliness of CBL cracking furnaces; it is also another successful example of the modular and standardized design approach adopted by SEI. It will lay a solid foundation for the newly built 1.5 million-ton ethylene plants as well as for expanding operations on an international scale.

. As of 20:38 on December 21, 2021, Sinopec Refining and Chemical’s 800,000-ton-per-year steam cracking unit had produced a total of 800,000 tons of ethylene; it exceeded the designed production volume in its first year of operation, with an estimated annual production of 810,000 tons of ethylene. The purity of the ethylene product reaches 99.97%, the ethylene recovery rate is 99.98%, and the hydrogen recovery rate is 94.5% – all of which are higher than the design values; numerous product quality indicators exceed international advanced levels. Currently, Sinopec Refining & Chemicals ranks first among Sinopec’s refineries of similar scale in terms of economic efficiency.

To promote the widespread use of domestic technologies, Sinochem Refining and Chemicals was willing to be the first to take the risk. “The localization rate of steam cracking units has reached 95%, and many new equipment and technologies have been successfully put into industrial use at Sinopec Refining. ”said Chen Yuhui, manager of the First Chemical Processing Department at Zhongke Refining and Chemicals. The 300,000-ton/year large-scale gas cracking furnace, which utilizes Sinopec’s largest proprietary patent technology, CBL, has completed its first long-duration operation at Sinopec Refining & Chemicals. This marks a new milestone for domestic independent ethylene production technologies and fills a significant gap in domestic technological capabilities. All seven cracking furnaces in the steam cracking unit feature a dual-chamber design, allowing two chambers to crack different feedstocks simultaneously, thereby providing good adaptability to various feedstocks. At the same time, internationally advanced domestic ultra-low nitrogen burners are used throughout, offering high energy utilization efficiency with a thermal efficiency of up to 95%; this year, the pyrolysis furnace ranked first in terms of thermal efficiency within Sinopec’s system. The \"heart\" of the unit – namely the steam cracking gas compressor, the propylene refrigeration compressor, and the ethylene refrigeration compressor – have successfully adopted China’s first set of domestically produced dry gas seals, thereby ending the situation in which all dry gas seals for these three types of compressors in ethylene production relied on imports. This development has significantly accelerated the progress in creating complete technological packages for steam cracking units. At present, the 12 dry gas seals and 6 control system seals of the “three units” are in good condition; all technical parameters meet the specified standards, and they have been operating safely for over 400 days.

Name: Sinopec 800,000 tons/year steam cracking unit for ethylene production. Researchers: Developed independently by the engineering construction company (SEI) and its partners. Features: The cracking and separation technologies used are those developed under SEI’s leadership; SEI is responsible for the overall project management. The domestic production rate of equipment for these cracking units is the highest in China. Highlight: The F-007 cracking furnace is the latest model of CBL-R type gas cracking furnace, developed independently by SEI and its partners. When using ethane as the feedstock, it has a production capacity of 300,000 tons of ethylene per year, making it the cracking furnace with the highest capacity among those currently in operation worldwide. On Donghai Island in Zhanjiang City, the sea water is clear and the sky is blue. A row of 60-meter-tall giants stood tall within Sinopec’s ethylene plant, creating a stunning sight against the backdrop of blue skies and white clouds.

The ethylene plant is the cornerstone of the petrochemical industry; the capacity to produce ethylene serves as a **indicator of the level of development in the petrochemical sector, and the cracking furnace is the key component of such plants. The Sinopec ethylene cracker utilizes Sinopec’s CBL patented technology, enabling the cracking of complex feedstocks such as ethane, propane, naphtha, and hydroprocessed tail oils; it can handle both gaseous and liquid materials, thereby enhancing the operational flexibility of ethylene production facilities. In the past, proprietary technologies for ethylene production were monopolized by foreign patent holders. In the early 1980s, at the founding of Sinopec, ethylene cracking technology was identified as a key project for development. Through a collaboration among SEI, Beijing Institute of Chemical Technology, and Nanjing Tianhua, the design of the process system and the development of key equipment were carried out. In November 1988, a prototype plant with an annual capacity of 20,000 tons was finally built in Liaoyang Chemical Fibers, enabling the localization of ethylene cracking technology and key equipment; this made China the fourth country, after the United States, Germany, and the Netherlands, to possess such cracking technology. Thereafter, as the leading entity in CBL pyrolysis technology, SEI focused on the development trends in ethylene production technologies and utilized patent applications as a means to achieve this goal. A total of 119 patents related to SEI pyrolysis were granted, including 32 invention patents. Five of these invention patents were issued in more than 10 countries, including the United States. SEI made significant efforts to advance technologies related to larger-scale pyrolysis furnaces, as well as furnace upgrades aimed at improving efficiency and performance, achieving substantial breakthroughs in these areas.

The original technical plan for Sinochem Refining’s 800,000-ton/year ethylene plant was based on the 800,000-ton/year ethylene plant at Wuhan Petrochemical. Since environmental assessment requirements stipulate that NOx emissions must be less than 70 milligrams per standard cubic meter, He Xiuou, the person in charge of SEI pyrolysis technology and a senior expert at the group company, decisively opted for full-bottom heating. He worked together with Tianhua Institute, the partner in development, to create burners that can achieve ultra-low NOx emissions in compliance with these requirements. To meet the requirements of advanced manufacturing processes, environmental protection standards, and project timelines, He Xiuou organized the CBL development team and the project design team to maximize the use of standardized and modular design approaches. Various options were studied, including the selection of pyrolysis furnace types, heating solutions, and methods for burning off residues in the furnace. After continuous optimization of the design, it was ultimately decided that the pyrolysis furnace would use a dual-chamber design with full bottom heating, as well as CBL-VI and CBL-R type radiant heating tubes. This approach not only met all the technical requirements but also helped to ensure timely project progress. “It is common for a pyrolyzer to pyrolyze gaseous feedstocks in one furnace chamber while simultaneously pyrolyzing liquid feedstocks in another chamber. Through optimization, it is possible to switch raw materials in real time online; switching raw materials in one furnace does not affect the normal operation of the other furnace. This provides greater flexibility in operation and helps to further reduce the impact that changes in raw materials have on the plant’s production. “Wu Jiawei, a pyrolysis process engineer at the First Chemical Processing Unit of Sinopec Refining & Chemicals who has been working in the pyrolysis facilities for 28 years, said with emotion, \"Back then, the conditions weren’t as good. To adjust the feedstock in a single furnace, it was necessary to stop the furnace, remove the existing feedstock, and then introduce new feedstock – each such switch took at least 6 hours.\" Now there are clear advantages in economic operations, and more confidence in safety and environmental protection management. ”