Wear Reducing Technology Newly Applied To Severe Pumping Services

Abstract

A U.S. Gulf Coast refinery had experienced accelerated internal wear of FCCU cycle oil pumps, often requiring entire case replacements. Compared to typical industry pump performance, run lengths were shorter, and cost per installed was higher. The application requires pumps capable of withstanding significant catalyst fines. Several wear resistant products have been used in pumps. However, all are limited due to the nature of the technologies. Thermal spray coatings and weld overlays can be used in “line of sight” applications, but not for small interior surfaces. Thermal sprays suffer from failures of the mechanical bond. There is preferential erosion of the soft matrix between the hard particles in weld overlays. Hard diffusion coatings (boronizing) are very thin and can be punctured by large abrasive particles. Infiltration brazed tungsten carbide cladding (IBTCC) solves many of these issues. IBTCC was developed for extreme wear applications with difficult geometries such as downhole drilling tools and coal fired power plants. IBTCC combines a true metallurgical bond and a dense, uniform distribution of tungsten carbide particles throughout the coating, to create excellent erosion resistance and toughness in complex geometries. After 13 months in service, an IBTCC cycle oil pump showed no significant signs of internal erosion. This technology has also been applied to FCCU fractionator bottoms and debutanizer reboiler services, with no signs to date of increased vibration or loss of hydraulic performance. The case study will show how internal material changes can improve pump longevity and produce maintenance cost savings.