SU0003324 - Laserfiche WebLink

Home Browse Search

CAPACITY Because the CPI plate pack is a gravity type separator, water.Normally,tank farm runoff will be less than 20 ppm if all oil globules its efficiency is determined by the rising or settling velocity of larger than 90 microns are removed.Refinery waste streams,however,will the smallest particles that will be intercepted. Capacity, generally be less than 20 ppm only when all oil globules larger than 60 then, cannot be stated as a fixed value. microns are removed The movement of particles is affected by the rising EXAMPLE: CPI Packs and Refinery Stream height,flow conditions,liquid flow velocity and particle size. Haw many CPI packs are required to reduce a refinery stream of 1700 Corrugated plates in the plate pack reduce the rising height GPM,containing 0.4% oil,to less than 30 ppm at a temperature of 68° F? and establish laminar flow conditions. Specific gravity, water= .995, Specific gravity, oil= .895. Flow velocity is related to the through-put. For Locate 68° F on the horizontal temperature scale of the chart below. example, with a standard plate space of 3/4" and quoted Project vertically to intercept 60 microns on the particle size scale.Next, capacity of 130 GPM, the flow velocity is 1.8 ft./min. This project horizontally until crossing the differential specific gravity of 0.1 (.995 versus.895). Then, project vertically down to the through-put scale means that all particles with a rising velocity of 0.42 in./min. and read 150 GPM Divide 1700 by 150 = 11.35 packs. Therefore, use (2.1 ft./hr.)will be intercepted.Particle size isdetermined by twelve packs. the difference in specific gravity between the water and oil, EXAMPLE: CPI Pack Load Versus Heavy Flow Conditions at a given temperature. When the water temperature is 68° What is the CPI pack load required during variqus rainfall intensities for F and the difference in specific gravity is 0.1, then all oil a given surface areal A nominal starting point for design is to use between particles 55 microns or larger will be recovered. 1/2"and 3/4"per hour of rainfall to determine the number of packs.The oil It follows that the ppm content of the effluent depends concentration and droplet size will vary under storm conditions. Al the upon the number of particles entering with the influent with beginning of the storm,much of the oil spilled on the platform and pads will a rising velocity of less than 0.42 in./min. To increase the wash into the sewer with a relatively low volume of water.Thus,while the oil separating efficiency of the CPI plate pack, these smaller concentration is high,typically 20003000 ppm,the oil droplets are large in particles must be intercepted.This can be done by reducing size (60 microns and larger). the (low velocity — that is, reducing the through put As the storm continues,the runoff rate increases while the oil concen tration drops sharply.Nearly all the spilled oil has rinsed away.Because of per pack. agitation, oil droplet size is reduced, with 2 to 3% dropping below 60 The chart below illustrates the relationship between microns.The concentration during this period normally is around 50 ppm. capacity, particle size,temperature and specific gravity for Although theoretical ly-4he flow through a standard pack will remain the Lancy Corrugated Plate Separator. laminar up to 700 GPM,at this load oil sludge particles tend to be washed CPS DESIGN/APPLICATION CONSIDERATIONS from the plates into the effluent.As a result,storm water design normally is limited to 300 GPM.This is chiefly because once the separator,downstream To achieve a desired final concentration,the size of oil droplets that from the plate pack, becomes coated with oil, it downgrades the effluent must be removed by the separator depends upon the origin of the waste- quality for several months PARAMETERS ARE DIFFERENTIAL SPECIFIC GRAVITY e� N6 O� 3 8 0. O 0 d 0 Z � 0 016 0 Og cc 0� U_ 0 W a0 O 0 O�b W Well fid. V) 0 6 J p Oe U �o 4 P 1-1 � O ` Q ti 1O CL b 9� `O >r R >r R S 5t S TEMP •F THROUGH-PUT-&PM/PACK-WITH 3/4" SPACING