PROCESS FOR TREATING WATER IN HEAVY OIL PRODUCTION USING COATED HEAT EXCHANGE UNITS

The invention relates to a process for treating a water stream produced in the recovery of heavy oil from geological formations comprising. The process includes a) injecting steam underground into a geological formation containing hydrocarbons and establishing a steam chamber; b) transferring heat from the steam chamber to the formation and mobilizing hydrocarbons for extraction from the formation; c) extracting the mobilized hydrocarbons from the formation and the hydrocarbons forming an emulsion with a portion of condensed water formed from the steam; d) separating mobilized hydrocarbons as a heavy oil product from the hydrocarbon-water emulsion to produce a water stream containing foulants that include residual hydrocarbons and solids; e) passing the water stream through a heat exchange unit comprising at least one tube wherein said the tube has a multi-layer coating comprising a melt flowable copolymer of tetrafluoroethylene adhered to the interior surface or exterior surface of said the tube; and f) removing said foulants from the water stream while altering the temperature of the water stream as the water stream passes through the heat exchange unit; wherein the multi-layer coating provides an anti-stick surface that reduces the deposition of foulants, on the interior or exterior surface of the tube as compared to the surface of the tube without the multi-layer coating being present, so as to avoid loss of efficiency in heat transfer and pluggage of the heat exchange unit.