Embed Size (px)
Citation preview
By Chris Long and Brent Welling
The need for consistent polymerdosage rates, coupled with highmaintenance costs incurred by
its existing metering pump, recentlyprompted a leading West Coast petro-leum producer to modify their methodof injecting emulsion polymer intocrude oil at the company’s dehydra-tion plant in Kern County, California.The facility had been using a low-flowreciprocating diaphragm pump for themetering process. By replacing the oldpump with a new progressive cavity(PC) metering pump they were able to:
1. Eliminate the bottleneck of incon-sistent chemical injection to thesystem
2. Drastically reduce pump maintenance
3. Improve safety4. Achieve a payback on the PC unit
in its first three months of opera-tion.
This Bakersfield petroleum produc-er generates more than 250,000 b/d ofoil and 90 million cu ft of natural gasper day, with proven reserves equiva-lent to just over one billion barrels ofoil. The dehydration plant services anarea of 20 sq. mi. near Taft, California,in the Midway Sunset Oil Fields. It hasa capacity of processing greater than20,000 b/d of the field’s heavy gravity(12-13 API) oil. The oil is pumped from
wells into one of three trunk lines.These trunk lines feed into a single 24”group line supplying the free waterknockout vessels at the oil dehydra-tion plant.
After the production leaves the freewater knockout (FWKO) vessels,Baker Petrolite RBW 6100 TM (emul-sion polymer) is injected into the oilusing the PC metering pump. The oil
from the FWKO vessels is distributedto seven heater treater vessels wherethe water content in the oil is reducedto less than 3%. Lease automatic cus-tody transfer units (LACT) then con-vey the dehydrated oil throughpipeline to the refinery.
Water from the heater treaters andFWKOs is transferred to one of two3000 b/d-capacity cone-bottom tanks,where the solids are jet-washed out,and the water is pumped through addi-tional filtration, clarification, and soft-ening processes, in the tertiary waterrecovery system. The clean water (lessthan 5 PPM solids) is then convertedinto steam by generators, and injectedinto the formation by way of injectionwells. This steam heats the oil, lowers
Flow diagram of Bakersfield area oil treating and dehydration plant. New meteringpump is located at the beginning of the dehydration process where crude oil from thefield is being split from main pipeline into separate flows to two free-water knockoutvessels (FWKOs).
Crude Oil Dehydration Plant Cuts Costs Using New Progressive Cavity Polymer-Metering Pump
OKThe new seepex MDP pump meters with-out pulses and has an integral DC-SCRcontroller. It can operate manually orfollow a 4-20 ma signal. Other drives arealso available.
Reduce your pulse rate.The new MDP can be used for flows from10cc/min. to 1 gpm and pressures to 175 psi.Call us today to reduce your pulse rate andyour blood pressure. 1-800-695-3659
Kynar® is a registered trade name for PVDF from Elf-Atochem
seepex Inc.511 Speedway DriveEnon, Ohio 45323(937) 864-7150Fax (937) [email protected]
We deliver your success
seepex MDP pump
the viscosity, driving it to the well boreand pumping it to the plant.
At this point Baker Petrolite’s RBW6100 TM emulsion polymer is injectedinto the production just upstream ofthe heater treaters. Baker Petrolite is adivision of Baker HughesIncorporated. This emulsion polymeris used for oil/water interface controlwithin the heater treaters.
In the past, a reciprocating-diaphragm-metering pump injectedthe polymer at a rate of 15 g/d. Due tothe pulsating nature of this pump, thepolymer will coagulate between thediaphragm and the pump chambercausing downtime (4 - 5 hours/week).The pump required weekly cleaningto remove the coagulated polymerfrom the pump chamber. During thisdowntime, the water quality would bebelow standard because of a lack ofpolymer treatment. In an attempt toremedy the situation an inline filterwas installed between the pump andthe polymer to screen out any type ofplugging agent; however, the impuri-ties would override the screen, andrequire labor-intensive cleaning everytwo days.
Looking for a solution to the poly-mer injection problem, Baker Petroliteturned to Cortech Engineering, Inc.,which supplied the plant with a type0015-24 MDP PC metering pump man-ufactured by seepex Inc., Enon, Ohio.With a maximum capacity of 3.1 LPH,the new unit consists of 316 stainlesssteel housing, a Kynar® rotor, and aBUNA stator. In operation, this posi-tive displacement pump’s single exter-nal helix rotor turns within a moldeddouble internal helix stator to formprogressively moving cavities creatingthe pumping action. The pump’s out-put is directly proportional to itsspeed, and its customized statorensures an identical compressionratio along the entire length of therotor/stator interface. The PC unit, byallowing a continuous pulse-free poly-mer flow, now does not permit thechemical time to set up and form clog-ging materials, and the pump’s designlets it shear and grind any solid mate-rials that might go through it.
As a result of replacing the recipro-cating diaphragm pump with the seep-ex unit, the plant has received numer-ous benefits. Since it was first installed
in April 2000, the new pump has oper-ated relatively maintenance free, elimi-nating: (a) the need for an inlinescreen, (b) the labor previouslyrequired for pump repair and screencleaning, and (c) the extra costs down-stream of reworking the sub-standardwater. In addition, by eliminating theinline screens, the new pump hasimproved plant safety, since there isless manual handling of the polymer-related equipment used in the process.At the same time, reduced routinemaintenance (the whole pump can betorn down and reassembled in five min-utes) has improved operator morale.Finally, the company notes that thenew metering pump has proved so suc-cessful that it easily paid for itself afterits first 90 days of service.
seepex Inc., 511 Speedway Drive, Enon, OH 45323.
800-695-3659
For more information, visit www.seepex.com
Chris Long is Area Manager, Baker PetroliteDivision, Baker Hughes, Inc., Bakersfield, CABrent Welling is Sales Representative, CortechEngineering, Inc., Anaheim, CA
Reprinted with permission from Chemical Equipment
