The 4,000-ton crawler crane at the China Coal Yulin Coal Deep Processing Base project was used to lift the 1,642-ton 2# propylene tower

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On August 21, at the site of the China Coal Yulin Coal Deep Processing Base project (the second phase of China Coal Shaanxi’s coal chemical project), after 6 hours of continuous work, Tower No. 2 was successfully lifted and transported to its designated position by a 4,000-ton class crawler crane – a powerful piece of machinery. This marked the successful installation of the tallest and heaviest core tower in this project. The 2# propylene tower is the \"heart\" of the propylene distillation system in the olefin separation unit; with a diameter of 7.6 meters, a height of 113.5 meters, and a weight of 1,642 tons, it appears like a giant steel dragon when viewed from below. Its main function is the distillation of propane and propylene; upon operation, it is expected to produce 35,100 tons of propane and 458,900 tons of propylene per year. Whether its lifting is successful or not is directly related to the success of the entire project. In the early stages of the project for the second phase of the company’s coal chemical complex, the project team innovatively adopted a model of \"manufacturing key processes inside the factory + coordinating labor protection efforts outside the factory,\" which enabled the entire manufacturing process, from constructing the 22-section tower structure to completing its final shaping, to be carried out within the factory premises. The platform, pipelines, insulation, and other accessories are modularly installed in the prefabrication plant; once the tower structure is on the ground, these accessories are attached to it, enabling the tower to be operational with lights turned on. This approach transforms high-altitude work into ground-level construction, significantly reducing the risks associated with cross-work and operations at heights. To ensure the successful lifting of this \"giant\", the project team made thorough plans and took proactive actions. They held a total of 18 special meetings with the design, manufacturing, and supervision teams, and the lifting plan was revised repeatedly with close attention to every detail: Could the load-bearing point of the main crane shift? How to stabilize the angle when using the auxiliary crane for tail pulling? How can the docking error of the tower be controlled within the millimeter range? What’s more thorough is that, from the flatness of the weld seams on the tower to the precision of component installation, the team addressed, monitored, and provided feedback on 32 issues in total. Each weld seam undergoes non-destructive testing, which is akin to giving the tower a health check; the pass rate for non-destructive testing of individual weld seams is as high as 98.3%. Based on the equipment parameters and site conditions, the project team adopted a dual-crane lifting scheme of \"4000-ton main crane for lifting + 1000-ton auxiliary crane for assisting\", using a 4000-ton truss-arm crawler crane as the main crane and a 1000-ton truss-arm crawler crane as an auxiliary crane to assist with the lifting process, while also carefully planning the lifting and transportation routes. At the lifting site of the 2# propylene tower on that day, the giant tower was lifted smoothly thanks to the precise coordination of two cranes; the commands given by the on-site supervisor were clear and calm, and the operators made precise adjustments, ensuring that everything proceeded in an orderly manner throughout the process. When the bottom of Tower 2 for propylene and the base were precisely aligned, warm applause erupted at the scene. During the lifting process, zero errors were recorded over 6 consecutive hours of operation, ensuring the smooth and precise vertical positioning of the equipment from a horizontal to a vertical position.