Stage regeneration

TOTAL invented two-stage regeneration for processing residue. 

R2R A catalytic cracking process using an ultrastable zeolite catalyst with two-stage regeneration. Developed by Institut Frangais du Petrole and used at Idemitsu Kosan s refineries at Aichi and Hokaido. In 1994, 13 existing plants had been converted to this process. 

The resins require two-stage regeneration with hydrochloric acid followed by sodium hydroxide. Although these chemicals may be locally produced, the cost... 

The emission of a helium nucleus in the final stage regenerates the initial carbon-12. The latter thus plays the role of a catalyst. The overall result is the fusion of four protons into a helium nucleus. At high temperatures, this cycle dominates over the proton-proton chain. Indeed thermal agitation facilitates penetration of the relatively high electrical barrier between proton and carbon nucleus. Whatever hydrogen fusion mechanism is prevalent, the star s mass determines the rate at which it consumes its nuclear fuel, and hence also its lifetime. The higher its mass, the more quickly it bums. 

An even larger one-quarter barrel per day circulating unit came very close to simulating both the 200 B/D demonstration unit and later commercial operations. It also possessed a two-stage regenerator and vented riser (both hallmarks of the RCC process). This allowed simulation and evaluation of additional RCC operating parameters. 

RFCC [Residual Fluid Catalytic Cracking] A process for cracking residues from petroleum distillation. It uses an ultrastable zeolite catalyst with two-stage regeneration. Originally developed in the early 1980s by Total Petroleum in Kansas and Oklahoma under the name R2R. Further developed by IFP with Stone and Webster and now more commonly known as RFCC. Twenty-six units had been licensed by 2003. 

Zhang. R. Adoption of Two-Stage Regeneration Technique on a FCC Unit, Petroleum Processing (Chinese), No. 9, pp, 8-13 (1988). 

Fig. 8. Installation of external catalyst cooler. 1, riser 2, first-stage regenerator 3, second-stage regenerator 4, catalyst cooler S, distributor I, combustion air II, fluidization air, III, water IV, steam and water.

The rate of vanadium mobility in FCCU s is dependent on many operating factors. These might be whether the unit is operated in lull or partial combustion, which will effect the average oxidation state of the vanadium. Other factors will be freshness of the vanadium, presumably older vanadium has had more of an opportunity to react with the catalyst matrix and become immobile. Steam concentration in the regenerator, catalyst make-up rate, temperature, and two-stage regeneration will all effect the mobility of vanadium. 

Figure 13.2-2 Kellogg orthoflow model F convertor with riser cracking and two-stage regeneration from Murphy and Soudek [30]).

Reduction of acepleiadylene with lithium at -80 leads in turn to the formation of a paratropic dianion ( H-n.m.r., 6 1.53 to -2.05) and a diatropic tetra-anion ( H-n.m.r., d S) [294], Both ions are stable in sealed tubes, even at room temperature. Reoxidation at any stage regenerates acepleiadylene. Reaction of these ions with dimethyl sulphate leads to the formation, respectively of dimethylated and unstable tetramethylated derivatives. 

Two-stage regeneration for processing residue feedstocks (S W, Total)... 

First two-stage regenerator with external dense phase cooling for highly contaminated residue feeds (UOP Ashland)... 

Total Resid Cracker Side-by-side configuration External straight vertical riser with two sets of multi-directional feed nozzles Two stage regeneration with external cyclones in the second stage... 

UOP RCC Side-by-side configuration Stacked two-stage regenerator with stage one in the top position... 

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