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Abstract:
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Feed quality is the primary variable involved in delayed coking. Research into the effect of feed quality, as well as the effects of the operating variables of temperature, pressure, and heavy gas oil recycle is covered in Chapter 3. Feed analysis and characterization are covered in Chapter 4. The traditional method is separation of resid into pseudocomponents based on solubility/absorption criteria. Besides being difScult and expensive, this approach has not provided data that can be reliably correlated to the coking process. A recent development in this area of research, the solvent-resid diagram, is also discussed.
Research into determining the reactions involved in delayed coking is reviewed in Chapter 5. One interesting aspect of delayed coking is that the reactions that produce coke proceed through an intermediate mesophase. Research into the formation of this second liquid phase and the transformation of mesophase to coke is reviewed. Hydrogen transfer reactions are another important aspect of the chemistry of delayed cokers, particularly coke quality. Research in this area is also reviewed.
Of course, the purpose of the research is the development of models to improve the ability to predict yields and quality. Most of the research has been into developing yield models. Three different modeling approaches that have been tried use kinetic, Monte Carlo, and empirical techniques. This, as well as research into models to predict coke quality, is reviewed. Models can also be used to improve the control and optimization of the delayed coking process. Advanced control and optimization techniques extensively use coker models. Some commonly used techniques are also reviewed in Chapter 6. |