Project Overview

Two high-speed, integrally geared butane pumps were in service at a Client’s light hydrocarbons unit. Various issues (e.g., loss of oil, contamination of oil) were known to be key risk factors for gearbox failure. A catastrophic gearbox failure would rapidly lead to a seal failure, causing a significant release of butane and possibly a fire. Rally was brought in to provide engineering solutions to mitigate the risk of future gearbox failures.

Pump Gearbox Safety Upgrades main Pump Gearbox Safety Upgrades first

Scope Definition

A plant HAZOP analysis recommended upgrading both pumps with dual seals (API Plans 13 and 53B) and new sensors to monitor pump operation. New alarms and circuitry would shut the pumps down on high vibration or low lube oil pressure.
In addition, Rally completed a LOPA / SIL analysis on the existing control infrastructure which resulted in a SIL 2 rating.

Detailed Deliverables

Rally issued material requisitions (MRs) for new API Plan 13/53B seal skids and various instruments. Rally also arranged for the existing gearboxes to be refurbished, one at a time, at a local shop. New vibration probes were installed, and the shafts, seals, and bearings were overhauled. This approach allowed the unit to continue operating while the gearbox upgrades were underway.
Rally produced a construction work package (CWP) to upgrade the pump mechanical seals, install the new seal skids, and make tie-ins to the tempered water and seal barrier fluid systems. Additional CWPs provided the cable connections and software updates to integrate the new vibration and pressure sensors with the existing DCS.

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