DUAL COALESCERS The use of oleophilic resin material in the coalescing process for the separation of oil from water is the basis of the Double Step Coalescer Technology. This system is specifically designed to treat hot steam condensate streams in order to remove oil contamination and to make them suitable to be recovered. The main characteristics of the double step coalescer are: High operating temperature Continuous operation without interruption of the service No chemical consumption Flexibility High preformances Such features make this technology suitable for steam condensate recovery in the most demanding applications such as: Oil and gas industry (refineries, oil pumping stations) Power plants Chemical and petrochemical industry Moreover, the coalescer technology may be successfully applied for deoiling waste water streams when very stringent parameters are to be met before discharge. COMPARISON WITH OTHER TECHNOLOGIES To have a clear view of the advantages of the double step coalescer technology, it is worth to compare it with the conventional treatment system for oily condensate which are based on pre-coat filter, possibly followed by activated carbon filters. Comparing the two systems, the following advantages of the coalescer technology may be pointed out. Higher operating temperature with the precoat filters the condensate needs to be cooled down to below 40-50 °C with the coalescer the condensate can be treated at a temperature up to 120°C Continuous operation without interruption of the service with the precoat filter the operation of the unit is discontinuos (precoat filter has to be backwashed (in case of 10ppm oil content in the condensate, the backwash is required every 4-6 days). The backwash produces a sludge which has to be disposed the operation f the coalescer is continuous. No interruption of service for backwashing or regeneration is required and no backwash sludge is produced No chemical consumption precoat filters require a continuous dosage of pre-coat material in the condensate to be treated (body feed). Such a dosage is in the range of 1-2 ppm of pre-coat material for each ppm of oil. As an average, the consumption of precoat material is in the range of at least 10 kg of carbon per kg of oil with coalescer no chemicals dosage required Flexibility The conventional system has a further limitation: when the oil content in the feed is variable, the dosage of body feed should be adjusted. However, as oil analysers are not very reliable instruments, usually the dosage of precoat is fixed at a given figure according to the average oil content. This means that if the oil content is lower than design, there will be a useless consumption of pre-coat material for body feed. On the other hand, if the oil content is higher than design, you will exhaust rapidly the activated carbon. the coalescer is a self adjusting process: with oil content in the condensate ranging from 10 to 100 ppm you will have always lower than 1 ppm at outlet outlet. Peaks up to 300 ppm of oil are also accepted. With pre-coat filters, when oil content is above 50 ppm, the condensate is usually wasted as the operating cost of the unit does not justify anymore its recovery High preformances in most cases the de-oiled condensate can be fed directly to the boiler. If activated carbon filter is installed, it will work as polisher only (to reduce the oil content from 1ppm to the value required by the boiler manufacturer. The life of carbon will thus be, at a standard design rate of 3 BV/h, more than two years. top