【Haichuan Good Articles Sharing】The development history of linear quenching boilers in China
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The development history of domestic linear quenching boilers: Due to the unique requirements in terms of process and structure for quenching heat exchangers, they have long been considered special equipment, relying mainly on imports from abroad, which results in high costs and long delivery times. However, with the introduction of complete sets of large-scale ethylene production facilities such as those in the Yanshan, Qilu, Yangtze, and Jinshan regions in China during the 1980s, Chinese design institutes and chemical machinery factories gradually gained the opportunity to gain in-depth knowledge of foreign quenching heat exchanger technologies, and embarked on a challenging path of domestic research, development, manufacturing, and substitution. In this process, “Tianhua Yuan” undoubtedly played an important role, emerging as a leader in this field. In 1985, Tianhua Institute, as one of the three development teams for the CBL northern furnace, took on the responsibility of developing and designing the quenching heat exchanger system associated with this furnace, while also providing mechanical manufacturing support. In the initial stage, the first CBL furnace employed a two-stage quenching technology, with 8 shell-and-tube exchangers designed for the first quenching stage, and 1 horizontal flexible thin-tube sheet exchanger used for the second quenching stage. The unit was successfully commissioned in 1988, marking a significant breakthrough in the localization of the quench heat exchangers for ethylene cracking units. The subsequently developed CBL furnace model also employs two-stage quenching technology, but the structure of the second quenching heat exchanger has been improved, adopting a vertical double-tube design with flow from top to bottom. With the rapid development of computer technology, FEA finite element analysis and CFD fluid dynamics methods have been gradually introduced into the research and development of quenching heat exchangers. These advanced technologies are used to conduct in-depth studies on the stress conditions of key components in heat exchangers as well as the flow field distribution, thereby providing a scientific basis for optimizing the flow channel structure. This enables the structure of the quench heat exchanger to be continuously improved and optimized. In 2000, Tianhua Institute successfully developed the linear quenching heat exchanger, which features a short residence time in the adiabatic section, high compatibility with various furnace types, low thermal stress, and a long operating cycle, and as a result has found wide industrial application. During subsequent operations, to address the problems encountered, Tianhua Institute upgraded the material of the inlet cone and improved the connection structure, with the aim of reducing the thermal stress on the inlet connectors and heat exchange tubes.
Thereafter, Tianhua Institute continued to innovate and successfully developed a new type of high-capacity rapid cooling heat exchanger. This heat exchanger features an efficient vertical shell-and-tube design, which boosts its processing capacity significantly and allows it to work perfectly with tubes designed for large throughput. It is not only suitable for use in large-capacity primary quenching heat exchangers, but can also be used as the first or second quenching heat exchanger in secondary quenching heat exchangers. This heat exchanger incorporates a number of innovative technologies: flexible thin tube sheets and elastic connectors are used at both the upper and lower ends, which effectively accommodate the differences in thermal expansion between the heat exchange tubes and the shell, while also reducing the temperature gradient in the thick tube sheets ； The connection between the inlet tube sheet and the heat exchange tubes is achieved using internal hole welding to ensure a secure connection ； The outer surface of the inlet tube sheet is cladded with a heat-resistant alloy to provide additional protection ； In addition, the design of the pyrolysis gas inlet flow channel was optimized, and measures such as anti-coking baffles were added.
The new rapid cooling heat exchanger developed by Tianhua Institute features numerous structural innovations, as well as significantly improved performance. This heat exchanger incorporates a number of cutting-edge technologies, including the use of flexible thin tube sheets and elastic connectors, as well as internal hole welding techniques and the deposition of heat-resistant alloys, which enable it to perform excellently in tasks involving large-scale rapid cooling. Furthermore, its unique cracking gas inlet flow channel design and anti-coking baffle, among other measures, further optimize the performance of the heat exchanger. It is worth noting that in addition to Tianhua Institute, there are several other chemical machinery manufacturing companies in China, such as Nanhua Machinery, Maoming Gravity, Qilu Chemical Machinery, and Harbin Boiler Factory; these companies have also accumulated extensive experience in the research, development, and supply of quenching heat exchangers. The joint efforts of these enterprises have driven the continuous advancement of quench heat exchanger technology in our country.
Tianhua Yuan, officially known as Tianhua Chemical Machinery and Automation Research and Design Institute Co., Ltd., has been dedicated to research and development in various fields such as chemical machinery, chemical engineering, and related equipment since its establishment in 1958. Through years of accumulation and development, Tianhua Institute has made significant progress in the field of quenching heat exchangers; its products not only feature innovative designs but also exhibit greatly improved performance. In addition, Tianhua Yuan is also widely used in various industries such as chemicals, petrochemicals, and oil fields, demonstrating its strong capabilities and influence. By 2021, Tianhua Institute had total assets of 2.9 billion yuan, reflecting its strong financial strength. In the same year, the hospital achieved operating revenue of 1.57 billion yuan, delivering remarkable results. Currently, Tianhua Institute has 925 employees on staff, of whom 72.1% are professional and technical personnel, highlighting its strong capabilities in research and development as well as technology. It is worth mentioning that the institute has 84 professor-level senior engineers, 195 professionals with senior titles, and 205 professionals with intermediate titles, totaling 384 high-caliber talents. At the same time, 5 people receive special government allowances, and 6 have been selected as leading talents in Gansu Province, further demonstrating Tianhua Institute’s outstanding status and influence in the industry.
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