Effluents continuous catalyst regeneration

Description The process consists of a reactor section, continuous catalyst regeneration (CCR) section and product-recovery section. Stacked radial-flow reactors (1) facilitate catalyst transfer to and from the CCR catalyst regeneration section (2). A charge heater and interheaters (3) achieve optimum conversion and selectivity for the endothermic reaction. Reactor effluent is separated into liquid and vapor products (4). The liquid product is sent to a stripper column (5) to remove light saturates from the C6 aromatic product. Vapor from the separator is compressed and sent to a gas recovery unit (6). The compressed vapor is then separated into a 95% pure hydrogen coproduct, a fuel-gas stream containing light byproducts and a recycled stream of unconverted LPG. 

The fluidized reactor system is similar to that of a refineiy FCC unit and consists of riser reactor, regenerator vessel, air compression, catalyst handling, flue-gas handling and feed and effluent heat recovery. Using this reactor system with continuous catalyst regeneration allows higher operating temperatures than with fixed-bed reactors so that paraffins, as well as olefins, are converted. The conversion of paraffins allows substantial quantities of paraffins in the feedstream and recycle of unconverted feed without need to separate olefins and paraffins. 

They may require pH adjustment and settling. These effluents should preferably be recycled or reused. Spent catalysts are usually sent for regeneration or disposed of in a secure landfill. Air emissions should be monitored aimually, except for nitrate acid plants, where nitrogen oxides should be monitored continuously. 

The reaction occurs over a relatively small zone in the catalyst bed. As the reaction moves down the catalyst bed, coke deposits deactivate the front part of the bed. The reaction continues down the bed until a substantial part of the catalyst is deactivated and unconverted methanol "breakthrough" is detected in the reactor effluent stream. Use of sufficient catalyst permits reactor onstream periods, or cycles, sufficiently long to avoid excessive regenerations. To enable this to be done onstream, multiple reactors are provided and operated in parallel on a cyclic mode. The New Zealand plant is designed to operate with four reactors onstream, with a fifth reactor in regeneration. 

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