AM-97-13 RESID FCC REGENERATORS: TECHNOLOGY OPTIONS AND EXPERIENCE

Description:

The fluid catalytic cracking (FCC) process is a key part of nearly every refinery conversion strategy. Although traditionally used to convert gas oils into liquefied petroleum gas (LPG), light olefins, gasoline, and distillate fuels, the FCC process is economically attractive for processing resid because of the lower cost of residual feeds compared to gas oils. Increased pressure on operating margins is leading more refiners to seek this path. Many different technology features enhance the capability of the FCC unit to process resid. Decisions on different features are influenced by how heavy and contaminated the feed may be and by many site-specific issues within the refinery. Since the early 198Os, technology advances in feed distribution, riser termination devices, and spent catalyst strippers have greatly improved FCC profitability. These advances allow refiners, under appropriate operating conditions, to increase the yields of light olefins, gasoline, or distillate, which are the more desirable and valuable products. At the same time, these advances have reduced the A coke of the operation, the coke deposited on the catalyst as it passes through the reaction system. The decrease in A coke reduces regenerator temperatures and relieves some of the headaches involved with processing resid feeds. However, regenerator design and capabilities continue to play a dominant role in the design of new resid FCC units, and they greatly influence the technology options and performance of,FCC unit revamps to process resid. This paper examines the technical and practical issues surrounding the selection of regenerator technology for FCC units that process resid. The uniqueness of each refinery situation has led UOP to develop a problem-solving approach to resid processing rather than seek a single “best” solution. Commercial examples are used to illustrate how site-specific issues at the refinery level influence technology choices. An appreciation of the difftculties of resid processing is necessary to fully understand the benefits of modem technology features. Although the concept of adding resid to the feed is not new, the tools that are applied to handle the negative consequences can make a dramatic difference in how effective resid processing can be for the refiner.