摘要 |
In the fluid catalytic cracking process, improved adaptive behavior of the catalyst section with the regenerator operating in the complete CO-burning mode is achieved by including, as elements of control, variable preheat of the oil feed and variable recycle of regenerated catalyst to spent catalyst. In response to excursions of the regenerated catalyst temperature, such as would be caused by change of feedstock, the oil preheat temperature and recycle ratio are altered in a direction to restore the regenerated catalyst temperature to a predetermined value. The improved control system extends the useful control range, and it also diminishes counterproductive changes in severity induced by disturbances such as change of feedstock quality.
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