罗门哈斯除油树脂资料-英文版.doc

ION EXCHANGE RESINS Update 10 Oct 2005WATER DE-OILING(coalescence process)Introduction The process was developed around 1980 by the French oil company Elf-Aquitaine (now Total Fina Elf) together with ANVAR, a governmental research institute. the resin used in all existing plants, was discontinued by Rohm and Haas in the 1990s due to very low sales.General principle of the process The water containing oil to be removed is passed through a bed of ion exchange resins on which a surfactant (a fatty amine) has been grafted. The surfactant makes the resin oleophilic, which means it attracts oil molecules. The resin bed is able to remove hydrocarbons from the water. Additionally it can also remove suspended solids by filtration. Two operating processes can be used: 1. Upflow loading (pure coalescence) The oily water passes through the resin bed from bottom to top. The resin beads adsorb oil on their surface, which forms a film around the beads and progressively grow to make droplets. When the droplets have reach a critical size, they float to the top of the coalescer where they are removed by skimming. The broken film around the resin beads grows again and the process continues indefinitely. This is a self-regenerating process. 2. Downflow loading (coalescence and filtration) The oily water passes through the bed from top to bottom. The resin beads adsorb the oil with the same mechanism as above, but once they are heavily loaded, they must be backwashed periodically to remove the oil. Suspended solids accumulated on the resin bed are also removed. When the amount of suspended solids in the feed is high, it is recommended to install a pre-filtration with a sand filter. The most attractive variant is the first one (upflow, pure coalescence) Details of the coalescence process The big droplets rise to the top following Stokes law: with v = velocity = density of the fluids = viscosity g = gravity constant d = diameter of the oil droplets Implementation of the coalescence process The coalescence and decantation steps are performed in vertical vessels. The oily water passes through a fixed (not fluidised) resin bed with a height of 200 to 400 mm, from bottom to top. The linear flow rate is about 10 m/h. The resin has a coarse particle size. At the surface of the resin bed, large hydrocarbon drops appear and are separated in a decanter above the resin bed. Numbered in and outlets 1. Oily feed water 2. Treated clean water 3. Recovered oil or hydrocarbons 4. Washing water inlet 5. Washing outletResin used in this process An oleophilic resin is made from a strongly acidic cation exchanger on which an aromatic fatty ammonium ion is attached. It could be a benzene or pyridine derivate. It is this fatty tail that attracts the oil and triggers the coalescence. Examples are shown below. The resin was called Duolite ROC110. Aromatic ammonium ionPyridinium ionCation resin bead a: ammonium b: fatty tail Performance With upflow loading, the treated water contains less than 1 mg/L of oil, which makes it suitable for use in a boiler. With downflow loading, the process associated with a primary separator (Turbiflux) produces a water with less than 15 mg/L of oil. The table below gives results obtained in industrial plants, with flow rates between 5 and 20 m3/h and temperatures between 20 and 100C. Hydrocarbon values were measured by infrared spectroscopy (NF T 90203). Type of feedSuspended solidsmg/LHydrocarbons in emulsionmg/LInletOutletRefinery condensate510-2001Pumping station (mineral oil)510-2001Ballast water3020-15010Oil well water30100-50015Process water (refinery, with sand pre-filter)30-10030-10010Advantages of the process Meets international reject specifications No moving part High filtration flow rate Small foot-print Very high resistance of the resin to attrition, chemical agents and temperature (up to 120C) Long life of filtration medium No chemical addition, thus no change in water mineral content and no sludge In coalescence mode (upflow), recovery of good quality hydrocarbons, with less than 0.5% water) Performance is independent from flow rateAreas of application The process is particularly useful in the following cases: Pollution control Recovery and recycling of the waste, e.g. boiler condensate Recovery of the oily substance, when this has a high value, e.g. in the perfume industryIt can be applied in several industries: Oil industry Production: oil well water and re-injection Transport: ballast water Refining and distribution: process water, waste, boiler condensatesOther industries Metallurgy: workshop waste for certain metals Food industry: edible oil factoriesProcess limitations Parameter limitRisk if exceededSuspended solids 5 mg/LClogging resin bedTemperature 130CResin degradationNo detergentsPoor coalescenceParaffinesDisturb coalescence at low temperatureSome references These references are old, and should be checked and completed Oil refinery Ambs, France (condensate