【Ten Years of Rapid Development in Chemical Processing Equipment】External Circulation Wall-Scraping Coolers for the SAN Unit Reactors in ABS Plants from 19625 to 2022

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Witnessing the decade-long rapid development of chemical processing equipment – praising the prosperous and strong China. Replies are rewarded; discussions are welcome. ------------------------------------------- Good news has come from a user in Liaoning related to an ABS production facility: thanks to the concerted efforts of the project team at Tianhua Institute, another independently developed product by this institute has achieved a significant breakthrough, with all 18 \"SAN unit reactor external circulation wall-scraping coolers\" being successfully put into operation at once. The successful commissioning of this device marks another new technology and achievement acquired by Tianhua Institute, as well as the opening up of a new field and market. ABS resin is one of the important engineering plastics, featuring high impact resistance as well as good heat and low-temperature resistance; it is widely used in home appliances, automobiles, and commercial equipment. The synthesis of SAN resin is one of the three main techniques for producing ABS resin. Acting as the continuous phase in ABS resin, it is synthesized primarily through bulk, suspension, emulsion, and solution polymerization methods. Since the bulk method for producing ABS resin features a high efficiency factor, it is currently the preferred method for manufacturing SAN resin. It is copolymerized from two monomers; when the conversion rate of bulk polymerization is maintained at 50%–70%, the increase in polymer molecular weight results in a high viscosity for the system (typically between 10 and 100 Pa·s), along with the release of large amounts of reaction heat. High viscosity and high exothermicity severely affect the stability of the reaction process; therefore, the removal of heat generated during polymerization is a critical problem that needs to be addressed urgently. Opportunities and challenges coexist, along with incentives and pressures. Over the past few decades, the \"SAN unit reactor external circulation wall-scraping cooler\" equipment, which can solve the aforementioned problems, has relied on imports from abroad, with foreign manufacturers holding a monopoly in the domestic market. Faced with the challenge of being constrained by others, the innovative team at Tianhua Institute’s Drying Laboratory took it upon itself to address and overcome technical challenges related to equipment, continuously exploring new directions and focusing on theoretical and technical research. By studying a large volume of relevant domestic and international literature, conducting numerous experimental tests and practical applications, and carrying out heat transfer calculations and numerical simulations based on this information, along with repeated evaluations from various perspectives, the design process included the incorporation of sealing systems, wall-scraping devices, hydraulic station systems, and automatic control programs in order to achieve comprehensive integration and testing of the equipment. As hard work pays off, after 3 years of diligent efforts by the innovation team, the \"SAN unit reactor external circulation cooler\", which possesses independent intellectual property rights owned by Tianhua Institute, was finally put into use and started operating successfully from the very first attempt. To date, this technology has obtained 1 utility model patent, with 1 invention patent under consideration. During normal operation of the ABS unit, the external circulation wall-scraping cooler of the SAN reactor continuously and effectively removes the heat generated during the reaction in that reactor, allowing the operating temperature inside the SAN reactor to be maintained at a reasonable level and ensuring the smooth and efficient progress of the polymerization reaction. Thanks to the device’s design, which includes a fully automatic reciprocating wall-scraping mechanism, it is able, during operation, not only to remove and cool the highly viscous media in the reactor but also to enable self-cleaning of the heat exchange tubes. This prevents the material from sticking and degrading, while ensuring a constant heat exchange efficiency throughout the entire process. Compared with imported equipment, the external circulation cooler for SAN unit reactors developed independently by Tianhua Institute can be widely applied in the fields of new materials and polymer materials. It enables continuous heat exchange for high-viscosity and highly hazardous media online. Moreover, through independent innovation, it reduces the capital investment and operational energy consumption of such systems. The development and successful deployment of this equipment are of great significance for improving the technical level of equipment and the overall industrial capacity in various sectors such as chemicals and environmental protection in China. Every honor is hard-earned, every success deserves celebration, every hardship must be remembered, and every new journey is taken without hesitation. Unfazed by difficulties and committed to diligent study, the people of Tianhua have persisted and strived day after day for decades, performing their duties with dedication, equipping themselves with knowledge, and achieving extraordinary things in their respective roles. Upholding such a spirit of craftsmanship characteristic of a great nation, Tianhua Institute has, through inheritance and research, as well as dedication and perseverance, created one after another example of \"Made in China\" products and high-quality equipment for a great nation… Although we have achieved some successes in certain fields, there is still a significant gap between us and the international top standards in many areas. We must constantly urge ourselves with a strong sense of urgency to improve our capabilities in independent innovation and development, to acquire independent intellectual property rights, and to break through technological monopolies. With the mission of enhancing the international competitiveness of China’s chemical equipment industry, we must work together with one heart and one mind on the right path toward the great rejuvenation of the Chinese nation.