Feed continuous catalyst regeneration

The process consists of a reactor section, continuous catalyst regeneration unit (CCR), and product recovery section. Stacked radial-flow reactors are used to minimize pressure drop and to facilitate catalyst recirculation to and from the CCR. The reactor feed consists solely of LPG plus the recycle of unconverted feed components no hydrogen is recycled. The liquid product contains about 92 wt% benzene, toluene, and xylenes (BTX) (Figure 6-7), with a balance of Cg aromatics and a low nonaromatic content. Therefore, the product could be used directly for the recovery of benzene by fractional distillation (without the extraction step needed in catalytic reforming). 

As practiced today, FCC is a fluidized-bed process with continuous catalyst regeneration which reUes on short contact in a riser reactor between the feed and catalyst, fluidized with an inert gas, followed by disengagement and catalyst regeneration to burn off coke deposits and return the catalyst to near-fresh activity. 

Description This process features moving bed reactors and a continuous catalyst regeneration system coupled with a hard, smoothflowing catalyst. Feed enters the reactor (1), passes radially through the moving catalyst bed, exits at the reactor bottom and proceeds in the same manner through the 2-3 remaining reactors (2). The robust... 

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. 

This is a very slow reaction under normal reforming operation. Feed composition, temperature, H2/hydrocarbon ratio, and the pressure strongly influence the rate of coke deposition. Modern catalysts produce less coke and allow operation under more severe conditions, such as those used in the cyclic and in the continuous catalyst regeneration (OCR) reformers. The different reforming technologies are briefly described later. 

I 5 Predictive Modeling of the Continuous Catalyst Regeneration (CCR) Reforming Process Table 5.25 Feed Properties. 

In the major catalytic processes of the petroleum and chemical industries, continuous and steady state conditions are the rule where the temperature, pressure, composition, and flow rate of the feed streams do not vary significantly. Transient operations occur during the start-up of a unit, usually occupying a small fraction of the time of a cycle from start-up to shut-down for maintenance or catalyst regeneration. 

A good example of the ruggedness of the beta zeolite catalyst can be found in the case of JLM s Blue Island (Illinois) Q-Max operation. The operation started in August 1996 as the first Q-Max process operation with UQP beta zeolite catalyst. Initial operating results were reported in 1997. The unit has continued to operate with stable performance for more than 7 yr without catalyst regeneration in spite of the presence of significant levels of feed contaminants. 

The types of reactors used for catalytic and noncatalytic gas-solid reactions are also often similar. Moving-bed reactors are used in blast furnaces and cement kilns. Fluidized-bed reactors are used for the roasting of sulflde ores and regeneration of catalytic cracking catalyst, and fixed-bed reactors are used to remove sulfur compounds from ammonia synthesis feed gas. When regeneration of the solid reactant is desired, two or more reactors operating in parallel are required if continuous, steady-state operation is to be achieved. 

The best solution appears to be the use of an almost insoluble liquid catalyst held within the pores of a suitable inert support. Supported liquid catalysts are well known and can be used with a continuous catalytic regeneration system similar to that developed for catalytic reforming processes. Haldor Topsoe has successfully tested trifluoromethane sulfonic acid in this way since 1993 with a variety of olefin feeds. " No formal regeneration was necessary apart from periodic removal of some catalyst for reimpregnation and the recovery of dissolved acid from the alkylate. Both catalyst and support are, therefore, recirculated. The small quantity of polymeric by-products formed (acid soluble oil) appears to be less tlm that formed in the sulfuric acid process, but slightly more than in the HF process. 

The activity of catalyst degrades with time. The loss of activity is primarily due to impurities in the FCC feed, such as nickel, vanadium, and sodium, and to thermal and hydrothermal deactivation mechanisms. To maintain the desired activity, fresh catalyst is continually added to the unit. Fresh catalyst is stored in a fresh catalyst hopper and, in most units, is added automatically to the regenerator via a catalyst loader. 

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