Applications
- Oil Production & RefineriesProcess
Improvement in Oil Refineries
A technical paper on this subject is available.Oil
Production EquipmentTreating
Refinery Effluent Water
Separation
of oil from refinery wastewater is carried out almost exclusively by gravity separation
using flotation of the oil droplets in the water, in American Petroleum Institute
(API) separators and in occasionally in large tanks. This
design is not sufficient to meet the effluent requirements in most areas, (according
the API study quoted in their "Design and Operation of Oil Water Separators,
Publication 421") and installation of coalescing media in the existing pits
is a good economic alternative to other more costly designs such as the use of
dissolved air floatation or other systems. Kirby
Mohr of MSR designed the world's largest API retrofit system for a US refinery.
The design flow rate for this system is 20,000 US gpm (4,600 m3/hour) and the
system is actually four separators constructed in a single structure. It was constructed
by dividing two existing API separators each in half and installing a new inlet/outlet
system in the center. This system has been in operation for several years and
is consistently providing effluent qualities of 5 mg/l or less. A
technical paper describing this and other refinery systems is available - please
use the Publication Request Form to request
it. Plant
Process ImprovementThere
are dozens of places in any oil refinery where it is necessary to separate aqueous
and hydrocarbon streams. These have often been mixed intentionally to facilitate
a chemical reaction or may result from water phases condensing within the process.
Rain water may also enter the tops of storage tanks and migrate to the bottom
of the hydrocarbon phases. MSR
Coalescing systems can be used almost anywhere there are two non-mixing phases
to be separated and can improve process operations and increase recovery of valuable
products. Once-Through
Cooling Water SystemsSome
refineries utilize "once-through" cooling systems using river or lake
water as the fluid for cooling process streams. This is an efficient and inexpensive
means of cooling but can be a water contamination source if any of the heat exchangers
leak. The usual design is to have the effluent water from the refinery exit the
plant by one or two pits designed as rudimentary API separators. This design is
not sufficient to meet the effluent requirements in most areas, so installation
of coalescing media in the existing pits is a good economic alternative to other
more costly designs such as the use of dissolved air floatation or cooling tower
systems. | 
