SU0002453 - Laserfiche WebLink

Home Browse Search

2.2 RESOURCE RECOVERY SYSTEM The resource recovery system will accept and recover used lubricating oils for sale and use within the facility. The process and equipment are discussed below and illustrated on the attached drawing No. M-12. 2.2.1 Process Design, Structures and Equipment a) After acceptance, the used lubricants are transferred into one of three used lubricant storage tanks (C-2). These are vertical, fixed—roof tanks vented through flame arrestors. The pump station (C-1) includes a positive displacement pump, electronic flow metering, and a duplex filter for removal of fines. Each storage tank will be fitted for steam coil heating to decrease the lubricant density as an aid to the first step of water separation. b) The used lubricants are metered continuously through a pre—heater (D-3) and into the first of three settling tanks (C-4) where oil/water seperation occurs. The lower density continuous phase lubricant rises over time and is directed to the next settling tank by a piping connection near the top of the tank. Water is drawn off the bottom of the cone shaped tanks until samples indicate increasing lubricant content. This process of progressive seperation removes approximately 80% of the entrained water droplets. c) The contaminated water is transferred to a Waste Water Holding Tank (C-5) of sufficient capacity to allow long term settling operations. In a batching operation, the oily water is skimmed off by a centrifugal pump drawing from near the top of the holding tank. This is transferred to the evaporation system for final seperation. The remaining quantity of relatively uncontaminated water is pumped to the rotary dryer inlet (see Section 2.1.1) for evaporation. d) The remaining entrained water, in very small droplet form, is removed (to specification limits) by a forced—circulation flash evaporation process. Used lubricants are transferred from the final settling tank into a vertical shell and tube heat exchanger (C-6) to achieve the final evaporation temperature. This flowrate is adjusted based on the volume of water removed during the settling process. The heat exchange vessel is always maintained full and under pressure to avoid phase changes. The lubricant is then forced through a spray nozzle into the evaporator column (B-7) and against an impingement plate. Recovered lubricant drains to the lower half- of the column where liquid level is maintained constant. Analysis of the lubricants exiting the column for water content determines the appropriate amount of recirculation required. Recovered lubricant, referred to as finished oil, is then stored in one of three storage tanks (B-8) . 9