Abstract: A methodology and system is disclosed which addresses outstanding needs of refiners to process cheaper crudes or blends of crudes. This method and system comprises a number of steps, including characterizing the impact of various constituents in the crude which result in fouling of heat exchangers; estimating model parameters; monitoring and predicting qualitative and quantitative performance; and determining optimal dosage of chemical treatments.

Abstract: A method for producing a transparent article comprises the steps of melt transesterifying a monomer mixture in the presence of a transesterification catalyst to produce a hydroquinone polycarbonate copolymer product comprising greater than 45 mole percent of structural units derived from the hydroquinone. The monomer mixture comprises a hydroquinone, at least one aromatic dihydroxy compound other than the hydroquinone, and a carbonic acid diester. The hydroquinone polycarbonate copolymer product is then heated to a highest processing temperature of 5° C. to 20° C. above a maximum melting melt temperature for the hydroquinone copolymer product for a sufficient period of time to render the hydroquinone polycarbonate copolymer product transparent upon cooling to ambient temperature; and cooling the hydroquinone polycarbonate copolymer product to produce the transparent article.