FCC hardware

Wrench, R. E., and Glasgow, P. E., The M.W. Kellogg Company, FCC Hardware Options, Paper No. 125C, presented at the AIChE National Meeting, Los Angeles, California, November 17-22, 1991. 

The results from the ACE FEB unit showed clearly that the low activity of the MAB catalyst would produce high slurry oil yields in present day FCC configurations, optimized for Y-zeolite based catalysts. Some adjustments of the FCC hardware would certainly be necessary to fully exploit the new catalyst selectivity potential. 

The basic FCC hardware can be divided into three the reactor-regenerator, product recovery and regenerator flue gas eleanup (Figure 5). This article will concentrate on reactor-regenerator engineering, but a cursory mention of the other two elements is included below. 

Once the performance of the FCC unit is optimized through the use of new catalyst and operating practices, the unit s profitability can be further improved by installing proven hardware technologies. The purpose of these technology upgrades is to enhance product selectivity... 

A conventional FCC unit can be an olefin machine with proper operating conditions and hardware. Catalysts with a low unit cell size and a high silica/alumina ratio favor olefins. Additionally, the addition of ZSM-5, with its lower acid site density and very high framework silica-alumina ratio, converts gasoline into olefins. A high reactor temperature and elimination of the post-riser residence time will also produce more olefins. Mechanical modification of the FCC riser for millisecond cracking has shown potential for maximizing olefin yield. 

The FCC process has a long history of innovation and will continue to play a key role in the overall success of the refining industry. The continuing developments will primarily be in the areas of catalyst, process, and hardware technologies. 

FCC feed, sulfur compounds in, 11 716 FCC unit emissions, 11 714 controlling, 11 689-694 FCC unit regenerators, 11 713 air distribution systems in, 11 726 catalyst emissions from, 11 714—715 CO2 emissions from, 11 720—721 configuration and mechanical hardware in, 11 722-731 cyclones in, 11 726-728 design of, 11 722-723 flue gas handling in, 11 729 fluidization in, 11 723-725 nitrogen oxide emissions from,... 

Consent decrees may specify hardware or additive solutions for individual applications. When a refiner agrees to implement a hardware solution, emissions limits are typically specified in the Consent Decree. This requires the refiner to design and implement an appropriately sized unit to meet these limits. With FCC additive solutions or hybrid solutions combining hardware and additives (such as a hydrotreater and SOj reduction additive), final emissions limits are not generally defined in the Consent Decree. Instead, a testing and demonstration program is defined to determine the performance of the additive(s) in the FCC unit at optimized concentrations. This may also be the case for some hardware solutions. The process to determine the optimized additive rate and process conditions is also identified. A baseline period and model is often used to determine additive effectiveness. A series of kick-out factors based upon additive performance are evaluated to determine the optimized level... 

The FCC process hardware and operation have continued to co-evolve with the catalyst and the changing economical and environmental requirements. 

The first commercial application of truly fluidized catal)4ic cracking was in 1942 at the Standard Oil Co. of New Jersey s Baton Rouge, LA. refinery. The vaporized oil was cracked in a dense, fluidized bed of catalyst ( bed cracking ). Details of that Model I FCC are given by Avidan et al. (1989). Various hardware improvements were made to bed crackers over the ensuing 30 years, but the advent of Davison s synthetic Y zeolites signalled the demise of bed crackers as state-of-art. 

Advances in catalysis and advances in hardware have gone hand-in-hand over the 50 year evolution of FCC. That will not change. 

Bartholic et al. (1991) have already reported on a commercial trial with a short contact FCC device (called Msec — millisecond catalytic cracking). The relative change in yields they observed compared to conventional FCC is reported in Table 9. Those yields are encouraging, but represent only the first step as the hardware and the catalyst are far from optimized. 

As with the reformer, the properties of the FCC gasoline are affected by the operating conditions, feedstock, catalyst selection, additives and new hardware technology. In addition, the FCC produces light olefins which are the building blocks for the major new clean ftiel processes such as etherification and alkylation. 

In general, the FCC model should converge within 20 seconds on recent computer hardware. If solution requires more than 20 seconds, it is likely that one or more specifications conflict... 

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