Pressure Surge Mitigation at High Temperature Tube Digestion Facility

Author(s): A. Wang, B. Haneman, C. Coleman
9th AQW Conference (International Alumina Quality Workshop), Perth, Australia, 18-22 March 2012

Abstract

The Yarwun Alumina Refinery identified the potential for high transient pressures through its tube digestion unit during operational upsets. As a result, these transient conditions can potentially expose plant, equipment and personnel to operational safety risks. Through extensive dynamic hydraulic modeling efforts, Hatch Associates assisted the refinery to investigate the potential causes of high transient pressures. Recommendations to either prevent or mitigate potential pressure surges were then made. This paper describes the methodology and tools used in establishing a dynamic hydraulic model for the piping system The model was then used to explore a number of mechanically passive protection measures, such as allocating and/or increasing surge dampers and modifying the isolation angle valve mechanical design, to mitigate the pressure surge. In addition to administrative controls, other instrumentation measures were also investigated to contribute to the layers of overpressure protection. The recommended measures are currently being implemented at the refinery.