Optimized Heat Management System Ensures Safe Sulfur Transport at Large LNG Plant
The Qatargas Sulphur Transfer Line project consisted of a 35 km, dual, 12 inch sulphur pipeline constructed to transfer molten sulphur from 11 producers to a sulphur pelletizer facility. Heat management system challenges included:
- Tight range of allowable temperature from 125ºC to 145ºC for molten sulphur with a set point of 135ºC along the entire length of pipeline.
- An outdoor large sulphur pipeline with significant weight, multiple flow paths, and vertical expansion loops every 150 m.
- Capability to re-melt and re-heat solidified sulphur without causing overheating or overexpansion.
- A 100% redundant heat management system for the pipeline.
To meet the needs of this challenging longline heating application, Pentair Thermal Management employed the following heat management system:
- Inherently safe Tracer skin-effect heat tracing system which has high exposure temperatures and efficient heat transfer to the pipe.
- State-of-the-art Raychem control and monitoring system with vacuum contactors.
- Finite element analysis to determine the temperature profile of sulphur across the cross section of the pipe.
- Fibre-optic based distributed temperature sensing system that provides dynamic pipeline temperature profile at each meter with 1ºC accuracy for the entire length.
- Multi-power heat delivery mechanism with 70% of installed power for normal operating conditions and 100% of installed power for heat-up/re-melt conditions.
- Multi-layer thermal insulation system with high temperature expanded perlite inner layer, load bearing closed cell foam outer layer and UV resistant jacket.
- Full service procurement of materials, project management, construction and commissioning of the pipeline.
Tracer skin-effect heat tracing system, Raychem control and monitoring system.
Pentair Thermal Management’ ability to engineer and integrate multiple technologies with its expertise in construction and commissioning heat management systems resulted in a world-class, safe, reliable, and efficient heat trace sulphur pipeline with the following benefits:
- The Tracer skin-effect heat tracing system not only minimized the number of circuits, but also resulted in better heat transfer and low temperature differential between the pipe and cable sheath, thus leading to a safer longline heating design.
- The finite element analysis and Raychem control and monitoring solutions ensured that the sulphur temperatures did not go outside the tight control temperature range under normal operating conditions.
- The fibre-optic distributed temperature sensing system provided continuous monitoring of the temperature along the entire length of the pipe. This helped to locate hotspots along the length of pipe during the re-melting process and in turn avoided excessive pressure generated by melting sulphur.
- Multi-power heat delivery mechanism and multi-layer insulation systems not only optimized the total operating costs of the longline heating system but also contributed to shorter re-melt duration.
- By assuming total responsibility of the heat management system, Pentair Thermal Management ensured that the project was completed on time, safely and to the satisfaction of the customer.