GRAPHALLOY® Enables Lean Amine Pump to Survive Flashing

The Problem

A Natural Gas plant in the Middle East had a multi-stage, heavy duty, vertical turbine pump (VS1), type 60-WUJ-2M, in Lean Amine service, that was continuously failing. Lean Amine is an organic compound that can absorb hydrogen sulfide and carbon dioxide from sour natural gas. The temperature of the pump service ranges from 6° C to 59° C and the shaft speed is 1770 RPM.

The pump had Schunk FH82A bushings installed, an antimony- impregnated hard carbon material, due to the low cost. This hard bearing material required the use of a hardened shaft. Due to the low viscosity hydrocarbon pumpage, the pump would experience flashing and run dry episodes. These hard carbon bearings would severely score the shaft which led to major repairs.

The GRAPHALLOY Solution

Working with the pump OEM’s design engineer in Italy, Graphalloy engineers recommended Graphalloy Babbitt-grade bushings to replace the hard carbon material.
Graphalloy wear components are self-lubricating, non-galling and work in a wide temperature range, from -450°F to +1000°F. Graphalloy is a softer material that will not damage the shaft, shaft sleeves or rotating
parts, thus enabling longer MTBR. These qualities make it a good match for severe service pumps, as it can survive frequent flashing and run dry episodes better than metal, carbons or plastic wear parts while protecting the rotating parts. Hardening the shaft is normally unnecessary with Graphalloy.

Results

Using Graphalloy bushings allowed tighter clearances and improved pump efficiencies. The upgraded pump went back into service and has been working well for several years now.