Mammoet aids refinery turnaround

In response to the growing demand for globally compliant fuels, Saudi Aramco’s 126,000-bpd Riyadh refinery embarked on a programme of upgrading its hydro-processing capability. It is one of Saudi Arabia’s oldest grassroots refineries and some of the plant’s machinery was outdated. Mammoet was approached by Jacobs Zate, the FEED and project management consultant, to complete a route survey and lifting study for this complex turnaround back in early 2018. In 2019, Al Rushaid Construction Company (ARCC), a Saudi industrial construction, maintenance and fabrication company, awarded Mammoet the contract to assist with the complex project.  

Its scope of work included the removal and replacement of existing refinery components, as well as the installation of new components, new foundations and platform structures. The entire operation involved a total of 109 lifts performed in three different areas of the refinery, including the replacement of eight hydrocracker reactors, 12 exchangers and two platformer exchangers.  

The old components and their replacements had to be transported and lifted in a congested refinery, with limited space, during a 40-day turnaround, all in the midst of the global Covid-19 pandemic. Mammoet deployed separate cranes, trailers and crews for each area to perform the work simultaneously. Optimised crane selection and ready availability, as well as the careful sequence of crane assembly within limited space, were key factors in the success of the project, Mammoet said.   

Critical lifts included the removal of eight of the existing hydrocracker reactors and the installation of new replacements, each weighing 450 tonnes. The old reactor vessels were designed with a single top lifting cover. Due to the age and likely deterioration of the refractory, the removal operation using the lifting cover was a particular concern. Mammoet said it developed two-point lifting trunnions, providing sufficient capacity to lift and tail the vessels with stresses within an acceptable range.