ENV-05-171 Design and Refinery Integration Issues Associated with FCC Scrubber Make-up Water and Blow-down Treatment

Description:

A number of oil refineries are planning or are in process of installing facilities to control flue gas stack emissions from their fluid catalytic cracking (FCC) units in order to comply with regulatory requirements. In some cases, the technology selected to remove particulate and SO2 will include wet gas scrubbers. These scrubbers require large quantities of make-up water and produce a wastewater (blowdown) stream requiring further treatment prior to discharge. This paper describes design and refinery integration issues associated with requirements for the FCC scrubber make-up water and the scrubber blowdown treatment system. The principal issues discussed in this article are: · Use and availability of reused water, including stripped sour water, as a source of FCC scrubber make-up · Use of fresh/plant water as FCC scrubber make-up · Options for disposition of the dissolved solids that result from scrubbing · Design considerations associated with the use of a clarifier for treating a hot and high salinity FCC scrubber blowdown stream · Process options available for dewatering of sludge generated at the FCC scrubber blowdown clarifier · Influence of the very high TDS concentrations associated with the FCC scrubber blowdown stream on the operational performance of the refinery biological treatment system · Feasibility of “direct discharge” of the treated FCC scrubber blowdown stream