Tallest Equipment Lifted into Place at Ma’aden’s WAS Project

On July 14, with the final section of the tail gas stack successfully lifted into place, the critical erection activities of the tallest equipment – the tail gas stack – in the Sulfuric Acid Plant and Phosphoric Acid Plant (SAP&PAP) area of the Ma’aden’s WAS Project was completed. This milestone lays the groundwork for subsequent installation of platforms and ancillary facilities, as well as commissioning activities.

The stack, with a total height of 86 meters including its base, could not be transported or lifted as a single piece due to constraints by transportation routes and site space. The project team adopted a construction approach of "shop prefabrication in sections plus on-site fit-up and welding." The stack was prefabricated in 7 sections at the shop, transported to site, where they were fit up and welded into 3 lifting packages. This final lift involved the use of 4 cranes of different capacities. Among them, a 600-ton crawler crane served as the lead crane for lifting and leading the movement of the stack, while a 250-ton crawler crane acted as the tailing crane for adjusting the lifting. Two truck cranes served as support cranes for personnel protection, auxiliary operations, and emergency rescue.

Before lifting, construction personnel first turned the stack section upright on the ground, and pre-installed ancillary components such as platforms and access ladders to minimize the amount of subsequent work at height. During the lifting process, the lead and tailing cranes maneuvered precisely. Construction personnel then promptly carried out interface alignment and girth welding, successfully completing the connection of the stack main body.