Case Study
Oil Refinery
Customer: Refinery
Objective
Solution
Results
Steam Tracing Keeps Lube Oil Flowing to Loading Rack at Northeastern Refinery
Often, the classic solution proves to be the optimal choice, from both technical and business standpoints. Such was the experience of a New Jersey, USA refinery, where steam tracing became the technology of choice for precision low-temperature control, together with reliable overheating protection.
To control temperature within feed lines from lube oil storage tanks to loading racks, the refinery considered and rejected electric temperature tracing on the basis of higher cost, a history of reliability trouble and difficulty of troubleshooting.
Facility Description
The refinery, with a capacity of 130,000 bbl/day of crude oil, recently upgraded its product from lube oil base stock to high-grade finished lube oils. They then marketed both bulk and blended product and a proprietary line. As part of the upgrade, the refinery undertook a $9 million conversion from bulk tank farm operations to loading rack operations. This facility loads rail cars and tanker trucks for transport to packaging operations and wholesale customers.
The Loading Rack Project
The refinery contracted Spirax Sarco, to design and implement a steam tracing system from its tank pumps through the loading rack to ensure economical, reliable product transfer year round. The refinery turned to steam tracing for the precision temperature control necessary to keep viscosity to a minimum without overheating and damaging the product.
Basic Control Approach
Control for the refinery’s steam tracing system is provided by Spirax Sarco’s direct acting steam control valves which maintain line temperature at 110°F with 50 psi steam. Since this supply is capable of heating the product to a destructive 300°F, control provided by the valves has to be precise.
Another concern in the system design was to guard against excessive heat transfer from the tracer to the product during no-flow conditions. Spirax Sarco met this concern by partnering with a company who provided pre-insulated tubing for uniform, controlled heat transfer to the transported product.
A third cornerstone of the control approach is use of thermodynamic steam traps with strainer connectors. They provide the reliable steam trap operation essential to precise temperature control.
System Description
The upgraded refinery has eight main storage tanks, each heated by dry steam provided by Spirax Sarco’s separators and control valves feeding prime surface heat exchangers. Six pumps serve six, 6-in. steam-traced main lines feeding two elevated loading stations, one for rail cars; the other serving two tank trucks simultaneously.
Comprising a quarter mile of piping in all, each main line has 12 tracers; 6 running east and 6 west. Each traced run is no longer than 200 ft. Steam tracing extends to mass flowmeters at the loading stations. Compressed air purges the lines downstream of the flowmeters to evacuate all product. Spirax Sarco washdown stations mix steam with water to aid in dealing with any spillage.
Troubleshooting and Maintainability Factors
With troubleshooting and low-cost maintenance as critical factors in the selection of steam tracing, Spirax Sarco uses in-line isolatable and repairable components throughout the installation. In-line quick change traps enable change-out in minutes instead of hours. Spirax Sarco manifolds with integral piston valves provide rapid tracer line isolation in the event of a steam leak. The numbering of every oil feed line enables rapid identification and isolation.
“We needed a tracing system that would accurately maintain lube oil temperature from the tank farm to the loading rack, and Spirax applied its products and expertise to ensure the goal was met.”Senior project engineer at Oil refinery
The Results
The refinery obtained accurate overheat protection using the Spirax Sarco control scheme in combination with the partnership who provided pre-insulated tubing. Additionally, the lowered viscosity of the safely heated oil has reduced pumping load and accelerated bulk loading operations year round. According to the refinery’s senior project engineer, “We needed a tracing system that would accurately maintain lube oil temperature from the tank farm to the loading rack, and Spirax applied its products and expertise to ensure the goal was met.”
Steady refinements to proven technology can often pay dividends in the real world when compared to cutting-edge methods. No better example exists than the low-maintenance, flexible low-temperature control afforded by properly designed steam tracing.