Resid FCC

Johnson, T. E., Resid FCC Regenerator Design, presented at the M.W. Kellogg Co. Refiing Technology seminar, Houston, Texas, February 9-10, 1995. 

Takatsuka, T. "Bottoms Cracking Capability of Resid FCC Catalysts", translation of 3apanese Publication, November 198. ... 

Generally speaking, resid FCC (RFCC) catalysts should be very effective in bottoms cracking, be metals tolerant, and coke and dry gas selective. Based on many years of fundamental research and industrial experiences, a series of RFCC catalysts, such as Orbit, DVR, and MLC, have been developed by the SINOPEC Research Institute of Petroleum Processing (RIPP) and successfully commercialized [1]. These catalysts are very effective in paraffinic residue cracking. However, in recent years more and more intermediate-based residue has been introduced into FCC units, and the performances of conventional RFCC catalysts are now unsatisfactory. Therefore, novel zeolites and matrices have been developed to formulate a new generation of RFCC catalysts with improved bottoms cracking activity and coke selectivity. 

Marine residual fuels bunker fuel oil Grades ISO RMA through RML marine residual fuel and bunker fuel are blended from components such as atmospheric resid, vacuum resid, visbreaker resid, FCC bottoms, low-grade distillate, and cracked components. Bunker fuel has a maximum viscosity of 550 cSt 122°F (50°C), density of 0.990 g/cc, and sediment of 0.1 wt%. ISO marine fuel oil viscosities range from 10 to 55 cSt 212°F (100°C). These fuels are used in slow-speed diesel engines and boilers. 

Several hydrocarbon processes are available for upgrading resid hydrotreating, Fluid Catalytic Cracking (FCC), coking etc., some more capital intensive than others. The most widely prevalent process is the FCC process. Therefore any advances in processing resid in FCC units will have wide application. This paper deals with concepts for developments in resid cracking, particularly in resid FCC development, evaluation and application. 

Naber et al (9) have demonstrated that FCC still has a considerable potential to remain the (resid) conversion "workhorse" of the oil industry. At present about 45% of the world s crude can be envisioned to be within the frontiers of Resid FCC (figure 1). Apart from the importance of FCC feed pretreatment and FCC unit design, also the impact of FCC catalyst performance is crucial to allow the processing of heavier feeds. 

Reviewing the main challenges in Resid FCC, we can establish the areas in which FCC catalyst improvements can play a role in enhancing the processability of res ids, (see Table II.)... 

Another interesting feature is that these LC pores result in an increase in the overal conversion. This effect is most pronounced when the catalyst is impregnated with Nicel (1500 ppm Nickel in MST) and at high coke yields. From this it seems obvious that pore mouth blocking is also a factor in Resid FCC, and that the presence of LC pores can be beneficial in this respect. Meso pores, are essential for reduction of the bottoms yield with aromatic and/or naphthenic feedstocks. (Table V.)... 

From the foregoing chapters it should be clear that the development of a successful FCC resid catalyst depends on several aspects the relative priorities of which will be determined by the refinery objectives, feedstock, FCC unit configuration and limitations. Still, it is worthwhile to distinguish certain "idealized objectives" in order to focus the catalyst development in this field. The advances in resid FCC catalyst development up to now have been mainly in the field of metal tolerance (metal traps), while also progress has... 

It is also clear that a good understanding of the FCC process objectives, limitations and configuration will be of crucial importance for the development of an optimized resid FCC catalyst formulation. 

P. O Connor, A.C. Pouwels and J.R. Wilcox "Evaluation of Resid FCC Catalysts" Symposium on Catalytic Cracking of Heavy Oils, paper 242E,... 

Zhao, W., and Xu, X. The Adoption of Complete Combustion Two-Stage Regeneration Technology on a Resid FCC Unit, Petroleum Processing (Chinese), No. 4, pp. 1-14 (1989). 

Resid FCC Operating Regimes and Catalyst Selection Akzo Nobel Catalyst Symposium,Noordwijk 1991 edited by S. Docter... 

Resid FCC operating regimes and catalyst selection", Akzo Catalyst Symposium 1994... 

Evaluation of Resid FCC catalysts", paper 242E, Nov.1992, AIChE Annual meeting. 

There are some very clear differences in the operation and catalyst requirements of various commercial Resid FCC (RFCC) units. In this paper, the differences between activity-limited and delta-coke-limited RFCC operations are elucidated and the related catalyst performance requirements and catalyst selection methods are discussed. The effect of the catalyst-to-oil ratio on conversion and on catalyst site utilization and poisoning plays a key role in the transition of an RFCC unit from a catalyst-activity-limited regime to a cat-to-oil-limited regime. 

An interesting example is the comparison of the operation of FCC units with and without heat removal. Resid FCC units with heat removal are often limited by the activity of the catalyst and consequently the (bottoms) conversion which can be obtained, while Resid FCC units without heat removal are mostly limited by the delta coke of the catalyst and hence resid intake or feed quality (e g., feed concarbon residue content). 

In this paper we address the differences between activity and delta-coke-limited Resid FCC and discuss the resulting appropriate operating regimes, related catalyst performance criteria and catalyst selection methods. 

As reported by Ho [12], the types of delta coke formed in Resid FCC can be classified based on the length of time needed for their formation. CCR coke will form nearly instantaneously at the inlet of the reactor and is therefore also called entrance coke." The second type of coke is formed by the adsorption of highly aromatic and basic materials on even weakly acidic surfaces this process also occurs quite rapidly. Finally, reaction or catalytic coke will form in what is clearly the slowest coke formation process. 

In general the main emphasis and progress in the development of low-delta-coke Resid FCC catalysts has been in the reduction of reaction coke [4,5,10], Table 2 gives an impression of the improvements which have been obtained in recent years. 

K.R. Rajagopalan, W.C. Cheng, W. Suarez, and C.C. Wear. "Resid FCC Catalyst Technology Today and Future." 1993 NPRA Annual Meeting, paper AM-93-53, March 1993. 

P. O Connor, L.A. Gerritsen, J.R. Pearce, P.H. Desai, A.P. Humphries, and S.J. Yanik. "Catalyst Development in Resid FCC." 1991 Akzo Catalysts Symposium, June 1991, Scheveningen. 

The importance of diffusion restrictions in FCC catalysis is often questioned. Short-contact-time pilot riser experiments confirm that combining zeolites with diffusion-enhancing matrices can result in significant product selectivity and product property improvements. The industrial benefits of a nonzeolite matrix on bottoms cracking in heavy vacuum gas oil (VGO) and resid FCC (RFCC) have also been confirmed in practice. Recently, some new methods have been used to measure the accessibility of FCC catalysts. 

Application When the process objective is maximum propylene production, specific technology features must be added to the fluid catalytic cracking (FCC)/resid FCC (RFCC) unit. The challenge is particularly great when the feedstock contains residue. 

Metals passivation in the resid FCC unit may also be accomplished through the addition of metal traps. Tin, barium titanate, strontium titanate, magnesium oxide, manganese oxide, and specialized zeolite types and contents have all been used for vanadium trapping. In addition, zeolites coated with alumina and catalyst particles coated with rare earth have also been applied to resist vanadium poisoning. Antimony, bismuth, and specialized active high crystalline aluminas have all been used successfully to counteract the negative effect of nickel in the FCC unit. 

O Connor, P., Gerritsen, L., Pierce, J., Desai, P. Humphries, A., Yanik, S., Catalyst Development in Resid FCC Akzo Catalysts Symposium, May 1991... 

Foskett, S., Edwards, M., AFX Catalyst Design and Application for Maximum Propylene in Resid FCC Albemarle Catalysts Symposium, Athens, 2007... 

US capacity reached 10 MMb/d in 1992 with over 350 FCC units FCC CFB catalyst regenerators described Resid FCC development... 

The operating conditions for CPP are more severe than for Resid FCC (RFCC) to an extent that it is allowed to be operated in existing idle RFCC units without the risk of damage to the fabric of the plant. 

Upgrading to a cracking refinery reduces the amount of low value fuel oil that a refinery yields (Figure 3). For Arabian Light Crude, heavy product (fuel oil) is reduced from 47% of refinery products to 27% by the addition of the FCC and ancillary equipment. The refinery product slate is now roughly in balance with Western European demands. The refinery is still long on fuel oil by U.S. product demands so further upgrading of the 1000°F+ residuum may be necessary (e.g., in a resid FCC or a coker). 

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