After Valero Energy Corp., San Antonio, Texas, purchased a 130,000-barrel-per-day refinery in Paulsboro, N.J., management decided to upgrade the product produced there from lube oil base stock to high-grade finished lube oils. The site now markets and distributes both bulk and blended product and the proprietary Valpar line.
As part of the upgrade, Valero converted the refinery from a bulk tank farm operation to a loading rack operation. Now the facility loads rail cars and tanker trucks for transport to packaging operations and wholesale customers.
To ensure economical, reliable movement of product through the loading rack operation, Valero went to steam-heating process expert Spirax Sarco Inc. of Cheltenham, England.
Spirax Sarco's assignment was to design and implement a turnkey steam-tracing system to maintain the precision temperature control necessary to keep product viscosity to a minimum without overheating and damaging the product.
Mission control
The temperature control system required three fundamental characteristics. First, it had to be precise. The line temperature had to be maintained at 110 Degrees F with 50 pounds per square inch (psi) of steam. Second, the system had to guard against excessive heat transfer from the tracer to the product during no-flow conditions, and last, the steam traps had to operate reliably.
The first and third demands were met through the installation of Spirax Sarco SB/121/ direct-acting steam control valves and UTD Thermo-Dynamic steam traps with strainer connectors.
The second design concern was addressed through a partnership with Thermon Americas, San Marcos, Texas. Thermon provided SafeTrace with pre-insulated tubing to ensure uniform, controlled heat transfer.
The MSC manifold with the SB/121 tracing control system centralizes steam distribution and condensate collection.
A quarter-mile of pipe
The upgraded refinery has eight main storage tanks, each heated by dry steam provided by Spirax Sarco separators and control valves feeding prime surface heat exchangers. Six pumps serve six 6-inch (in.) steam-traced main lines feeding two elevated loading stations: one for rail cars and the other for tank trucks.
The system uses a quarter-mile of pipe. Each main line has 12 tracers ," six running east and six running west. Each traced run is no longer than 200 feet.
Steam tracing extends to mass flowmeters at the loading stations. Compressed air purges the lines downstream of the flowmeters to evacuate the oil products. Hose cleanup stations mix steam with water to aid in dealing with spillage.
The Spirax Sarco/Thermon tracing arrangement gave the Valero Refinery the overheating protection it needed. At the same time, the oil's lower viscosity has reduced pumping loads and accelerated bulk load operations year round.
For more information about Spirax Sarco, Select 495 at www.chemicalprocessing.com/cp/reader_service.
