【Major Chemical Equipment】039-2×2.25 million tons/year – the largest p-xylene adsorption tower
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This post was last edited by Desert Fish on 2022-3-23 at 11:31. The past decade has been a period of rapid development for China’s chemical industry, with the emergence of many new processes, products, and equipment. China’s chemical processing equipment has also seen significant progress, which in turn has contributed to the swift advancement of the petrochemical industry. Here, we have compiled some of the achievements and breakthroughs made by Chinese equipment manufacturers in terms of larger-scale production and localization of equipment. Everyone is welcome to share, discuss, and exchange ideas; let’s cheer for Made in China and support the development of chemical processing equipment! *********************************** On June 16, the world’s largest adsorption tower – the adsorption tower for Hengli Petrochemical’s 2×2.25 million tons per year p-xylene production facility – which was manufactured by CNPC No.7 Construction Equipment Manufacturing Branch, was loaded onto a ship at Huangdao Port for shipment. It is the equipment with the largest annual production capacity and the most advanced design among similar products in the world today. It is reported that Hengli Petrochemical’s 2×2.25 million tons per year p-xylene production units are two separate facilities with a combined annual capacity of 4.5 million tons. They form an important part of Hengli Petrochemical’s 20 million tons per year integrated refining and chemical processing project, aimed at addressing the shortage of p-xylene, a key chemical raw material in China, and the over-reliance on imports for this substance.
The sheer scale of being the largest in the world brings with it extraordinary challenges. The adsorption towers utilize patented technology from the French company Axens. Construction began in May 2017, and it took a year to build the four adsorption towers; numerous difficulties were overcome during this process, demonstrating the technical integration capabilities and innovation skills of the equipment manufacturing division. During the manufacturing process, Qijian Equipment Manufacturing Branch applied 14 key technologies innovatively to ensure the smooth progress of the project: the self-developed lifting device for flipping cylinder sections without hangers enables the free flipping of cylinder sections weighing 60 tons ； The independently developed and constructed detachable, convenient heat treatment furnace, measuring 12 meters in length, 12 meters in width, and 13 meters in height, successfully carries out equipment heat treatment with high quality and efficiency ； Manufacturing and installation technology for the annular chambers of adsorption towers; the quality of prefabricated annular chambers, their cleanliness, and airtightness tests all reach the highest standards among domestic manufacturers ； The large number of non-radial connectors are installed with precise positioning, using tooling for positioning and accurate measurement through aerial wiring, to keep the deviation in the position of all connectors within 2 mm ； The coaxiality control technology for the central tube and the shell ensures that the coaxiality between the central tube of the adsorption tower and the cylinder body during installation is no more than 5 mm……
The 【Haichuan Equipment Guessing】 series is being updated continuously in 2022; all Haichuan fans are welcome to participate actively! https://bbs.hcbbs.com/thread-2079686-1-1.html (Source: Huahai Chuanliu – Haichuan Chemical Industry Forum) Summary post on the series 【Major Equipment in the Chemical Equipment Industry】 https://bbs.hcbbs.com/thread-3312079-1-1.html (Source: Huahai Chuanliu – Haichuan Chemical Industry Forum) Summary post discussing the components of cracking furnace equipment for 【Ethylene Cracking】 https://bbs.hcbbs.com/thread-3308724-1-1.html (Source: Huahai Chuanliu – Haichuan Chemical Industry Forum)
In the past, xylene towers could only be manufactured in sections at the factory; upon arrival at the construction site, these sections were assembled and lifted into place one by one. After that, a full-scale scaffold was erected up to the top of the tower, followed by the installation of the internal components, insulation, and pipelines attached to the tower. This approach required a large amount of space, took a long time to complete, and posed safety risks at heights; it was one of the key path activities on the entire construction site.
Only a significant increase in equipment manufacturing capacity and transportation capacity can lead to the scaling up of equipment production
Moreover, the overall lifting capacity of large-scale equipment is necessary to install such large devices.
The adsorption tower is the most critical equipment in the PX plant. It uses a solid adsorbent, a liquid-phase eluent, and a fluid distribution device to obtain a high-purity p-xylene extract from a mixed feed at high yield. The annular chamber, as the greatest challenge in the construction of adsorption towers, has always been a focus of attention from all parties, while the airtightness test is the most critical inspection step for this chamber. Experts from Axens, the French patent holder for adsorption towers, came to the site in person to conduct inspections, which illustrates the importance of this matter.