【In-depth Discussion on Modular Installation of HaiChuan】Case Study – Lifting Begins on the Large-scale Steel Structure Modules for ZhongKe Catalytic Cracking

To reduce the safety risks associated with work at heights and to improve quality control during installation as well as construction efficiency, both the contractor and Shijian Installation have placed great emphasis on careful planning. Based on the height of the framework and the actual conditions of the lifting equipment on site, the framework was divided into 4 sections for installation; the elevation of the first section ranges from 0 to 8 meters； The planning calls for using small cranes to lift each column individually, which facilitates leveling and aligning each column and thus lays a solid foundation for the installation of the upper-level frames. The main beams, secondary beams, and diagonal supports are assembled and lifted in smaller sections to minimize work at heights ； The elevation of the second section ranges from 8 meters to 25 meters ； All components are assembled in large sections on the ground along the axis of the steel structure frame columns, and then lifted and installed in sections using medium-sized cranes; the third section is at an elevation of 25 to 40 meters ； The fourth section ranges in elevation from 40 meters to 52.9 meters and is divided into six rectangular modules. The steel columns, main beams, secondary beams, tensioning supports, platform grating sheets, as well as the scaffolding and work platforms for construction workers to climb on, are all assembled into framework modules at a height of 0 to 5.2 meters above the ground, after which these modules are lifted and installed using large cranes.

Since the installation and modular assembly of this framework began on the ground in late March, the site workers at Shijian have strictly followed the planned requirements, construction plans, and standards for the first prototype in order to assemble it properly, ensuring that each pillar and steel beam is installed vertically and horizontally, so that once the framework components are assembled, its geometric dimensions are accurate. By the end of June, the first and second sections of the steel structure below 25 meters in height of this framework had been installed, and the six steel structure frame modules for the third and fourth sections were also completed through modular assembly at the assembly site and the steel structure prefabrication site. Following joint inspections and evaluations by the owner’s quality supervision office, the contractor, the supervisor, and all other parties involved in the construction, it was confirmed that all technical parameters of the installed first and second sections of the framework as well as the six modules met the requirements specified in the design documents and relevant standards.

On July 20, once the 600-ton crane, a large piece of equipment supplied by the shipping company, was in place, Shijian Installation promptly organized the crane operators and installation workers to work closely together in preparation for the lifting process. They then began the task of lifting the six steel structure modules. It is known that the largest of these modules measures 10.6 meters in length, 5.2 meters in width, 14.6 meters in height, and weighs 95 tons； The maximum lifting height is 60 meters, and the maximum lifting distance is 50 meters. On the afternoon of the 21st, the drivers from Shijian Company’s Installation, Lifting and Transportation Division worked together efficiently to lift the large 600-ton crane. In less than two hours, they successfully lifted and installed the first set of modules, which were 7.5 meters long, 5.2 meters wide, 14.6 meters high, and weighed 36 tons; the lifting distance was up to 50 meters, and the installation height was between 25 and 40 meters.

With the careful organization and coordination of the Zhongke Project Department at Shijian Company, and through the diligent efforts of over 130 construction workers from teams such as the installation team, the anti-corrosion team, and the scaffolding team over a period of one and a half months, another 4 large towers for the 800,000 tons per year ethylene steam cracking unit in the Zhongke Refining and Chemicals project were successfully lifted and installed in modular form in mid-April. To date, 16 out of the 18 \"floor-standing\" large tower units for this facility have been installed, and the completion of the installation of these large towers is within sight. The four large columns in the cold zone of the steam cracking unit – for high-pressure depropanization, low-pressure depropanization, demethanization, and deethanization – are like four siblings. Their heights are 43.5 meters, 59 meters, 49 meters, and 50 meters respectively. After modular assembly, their weights are 287 tons, 175 tons, 315 tons, and 320 tons respectively. In total, these four columns come with structural elements such as tower platforms, ladders, and pipe supports, weighing 141 tons. Additionally, there are over a thousand meters of pipes attached to the towers, with a diameter of 2678 inches; the insulation material used amounts to 51 cubic meters, the cooling material to 345 cubic meters, and the aluminum cladding covers an area of 3775 square meters. Electrical lighting has also been installed. The 15 large towers to be constructed using modular methods after the Spring Festival were, according to the plan, initially subject to the allocation of most labor and machinery to the three towers related to quench oil, quench water, and ethylene distillation – towers that are large in size – as well as those that needed to be lifted and installed urgently, in order to make room for civil works, underground pipelines, and the installation of other equipment. As a result, it was not until early March that resources were made available for the installation of the steel structures for these 4 towers; pipeline installation, along with insulation and cooling work, began in mid-March. According to the lifting schedule set for mid-April, the modular construction of these 4 large towers involves challenging and complex tasks. Shi Jian attaches great importance to this matter. To ensure timely completion, it has mobilized 4 high-quality, highly competent installation teams, with each team responsible for the steel structure and piping installation work for one of the large towers. Additionally, 2 anti-corrosion and insulation teams have been assigned, with each team handling the insulation work for two towers. A competition aimed at improving safety, quality, speed, project timeline, construction organization, and civilized construction practices was launched among the various installation and anti-corrosion/insulation teams working on the 4 large towers. Daily meetings were held to address any issues that arose and to plan the tasks for the following day, resulting in a dynamic atmosphere of competition and hard work at the construction sites of these 4 large towers. The modular assembly of the 4 towers was completed successively starting from April 7th. Thereafter, Shijian began lifting and installing the large-scale equipment in close coordination with the installation process. Demonstrating a spirit of not fearing fatigue and of working continuously, they worked together with determination and finally managed to lift the 4th tower on April 19th. They completed the installation of all 4 towers safely, to high quality, and on schedule, which earned them widespread praise from the owner’s supervisor at Sinopec Refining & Chemicals as well as from the contractors at Sinopec Engineering Company. (Gao Mingliang)