Regeneration air

The expansion turbine converts the dynamic energy of the flue gas into mechanical energy. The recoverable energy is determined by the pressure drop through the expander, the expander inlet temperature, and the mass flow of gas (66). This power is then typically used to drive the regenerator air blower. 

P. E. Glascow and A. A. Murica, "Process and Mechanical Design Considerations for ECC Regeneration Air Distributors," presented at Katalistiks... 

The spent catalyst is withdrawn from the bottom of the reactor and stripped with steam to vaporize the hydrocarbons remaining on the surface. Stripping also removes most of the hydrocarbon vapors which are entrained between the particles of catalyst. Without stripping, hydrocarbon products would be carried to the regenerator and needlessly burned consuming much of the regeneration air, and decreasing yield of useful products. 

Hydroprocessing reduces the Conradson carbon residue of heavy oils. Conradson carbon residue becomes coke in the FCC reactor. This excess coke must be burned in the regenerator, increasing regenerator air requirements. 

Oxygen enrichment. In a cat cracker, which is either air blower or regenerator velocity limited, enrichment of the regenerator air can increase capacity or conversion provided there is good air/ catalyst distribution and that the extra oxygen does not just burn CO to CO2. 

ASHRAE, Atlanta (1992)]. Process air stream 6, to be conditioned, passes through the adsorbent wheel, where it is dried. This is a non-isothermal process due to the release of heat of adsorption and transfer of heat from a wheel that may be above ambient temperature. The dry but heated air (7) is cooled in a heat exchanger that can be a thermal wheel. This stream (8) is further cooled, and the humidity adjusted back up to a comfort range by direct contact evaporative cooling to provide supply air. Regeneration air stream 1, which can be ambient air or exhausted air, is evaporatively cooled to provide a heat sink for the hot,... 

The pressure balance should be examined to determine the normal pressure readings in the reactor, regenerator, air system, flue gas system, and main fractionator and overhead system. These need to be followed on a time basis and plotted against variables such as feed rate, wet gas rate, and dry gas rate to see if and where problems may occur. Adjustments may be possible if the spent or regenerated catalyst slide valve delta P is at a minimum to provide more operating room. 

Description The CATOFIN reaction system consists of parallel fixed-bed reactors and a regeneration air system. The reactors are cycled through a sequence consisting of reaction, regeneration and evacuation/purge steps. Multiple reactors are used so that the reactor feed/product system and regeneration air system operate in a continuous manner. 

Gamblin, B., Newton, D., and Grant, C. X-Ray Characterization of the Gas Flow Patterns from FCC Regenerator Air Rising Nozzles, in Circulating Fluidized Bed Technology IV (Amos A. Avidan, ed.), pp. 595-600. Somerset, Pennsylvania (1993). 

Circulating pump Silicagel regeneration unit Regeneration air fan Silicagel air dehumidifier... 

Process cycle. All commercial Houdry units were built with at least three catalyst cases in order to permit continuous flow of oil feed and regeneration air. A simplified flow diagram of a Houdry plant is shown in Figure I a photograph is shown in Figure 2. The feed is passed... 

A heat balance around the catalyst-case area of a Houdry plant indicates that 69% of the heat from combustion of coke is used to generate steam, and 14% to preheat regeneration air. Heat of cracking absorbs 7 %, and minor amounts are removed by oil vapors, regeneration gases, and radiation losses (238). A typical temperature pattern during a complete cycle is shown in Figure 7. 

Solid desiccant materials are arranged in a variety of ways in desiccant dehumidification systems. A large desiccant surface area in contact with the air stream is desirable, and a way to bring regeneration air to the desiccant material is necessary. 

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