FCC preparation

With Ga-Beta it was found that, when the Si/Ga ratio increased from 10 to 40, the number of strong sites decreased drastically for Si/Ga between 10 and 25 and then reached a plateau above Si/Ga = 25 [53], The strength and density of acid sites in H(Ga, La)-Y were also found to be lower than those in HY crystals of the type used in FCC preparation (LZY-82) [250], Similar catalytic selectivities were obtained for both Ga-ZSM5 and A1-ZSM5 in Prins condensation of isobutylene with formaldehyde. Catalytic tests coupled with microcalorimetric measurements have shown that medium to weak acid strength sites favor the selectivity to isoprene [254],... 

ML Occelli, H Eckert, M Kalwei, A Wolker, A Auroux. The effects of steam-aging temperature on the properties of an HY zeolite of the type used in FCC preparations, in "Fluid Catalytic Cracking V Technology for Next Century", M L Occelli, P. Oi Connor Eds. Elsevier, Amsterdam, 2001. 

The strength and density of acid sites in H-(Ga,La)-Y have also been found to be lower than those in H-Y crystals of the type used in FCC preparation (LZY-82) [237]. 

The objective of the FCC is to define food-grade chemicals in terms of the characteristics that estabUsh identity, strength, and quahty. It provides specifications in monograph form for some 900 food additives, together with analytical test procedures by which compliance with the specifications can be determined. The third edition was pubUshed in 1981 supplements followed in 1983, 1986, 1991, and 1993. The fourth edition is in preparation as of this writing and is to include monographs for almost 1000 food chemicals, including flavors. 

Benzoic acid is suppHed to this market in the form of salts because the benzoate salts have a high solubiUty in water and aqueous stock solutions of up to 35% can easily be prepared. In addition, it is easier, and therefore cheaper, to purify sodium and potassium benzoate than to produce the USP/FCC grade of benzoic acid. 

The lithium benzamidinates Li[PhC(NR)2] (R = Cy, Pr ) and Li[2,4,6-(Cp3)3C6H2C(NCy)2] have been prepared analogously. Reaction of FcLi (Fc = ferrocenyl) with 1,3-dicyclohexylcarbodiimide ( = DCC, Scheme 6), followed by addition of water, afforded the ferrocene-substituted amidine Fc(NCy)NHCy in 50% yield. The amidine is readily deprotonated by LLN(SiMe3)2 or NaN(SiMe3)2 to yield the alkali metal amidinates, Li[FcC(NCy)2l and Na[FcC(NCy)2l in high yields. ... 

Heavy fractions (e.g., vacuum gas oils) and residues HDP might involve both, hydrotreatment and hydrocracking operations. HDT, in this case, is a feed pretreatment, for preparation to another process unit, which might be a HCK unit. This process combination, HDT-HCK can be used on Cycle Oil (FCC, coker), VGO (SR and coker) and SR residues (atmospheric and vacuum). It can be carried out in a single reactor with more than one catalyst, or in more than one reactor. 

VGO HDT is carried out at temperatures from 350°C to 420°C, pressures beginning at near 1000 to probably more than 2000 psig, and space velocity between 1 and 2h 1. Preferred catalysts may be NiMo or graded beds [94], depending on the application (feed preparation for FCC or integration to HCK), the quality of the feed and on the specifications required for the product. 

Resids HDT is carried out at temperatures between 360°C and 450°C, pressures from about 1500 to 3000psig, and 0.2 to lh-1 of space velocity. Graded catalyst beds combining CoMo and NiMo catalysts can be adapted to the quality of the feedstock and depending on whether atmospheric or vacuum residues are going to be treated. HDT of resids is seen as a feedstock pretreatment for preparing feedstock for either mixed with ordinary FCC feeds or for HCK (mixed with VGO or to a resid HCK). The advantages... 

Fabry-Perot cavity, 14 849, 850 Fabry-Perot etalons, 11 151, 152 Face-centered cube lattice, 8 114t Face-centered cubic (FCC) crystal structure in Ni-base alloys, 13 512 of spinel ferrites, 11 60 Facial makup, 7 846-847 Facial preparations, 7 842t Facial tridendate ligand, 7 578 Facihtated transport, 15 826-827 carrier, 15 845-846... 

A more desirable strategy is to prepare catalysts that will aromatize the gasoline without yield loss. Aromatization is thermodynamically favorable under FCC conditions of temperature (- SOO C) and pressure ( 2 atm). Blending studies show that the increase in research octane is about proportional to the amount of added aromatics. Figure 4. However, motor octane does not respond to initial increases in aromatic content in the blend but rises more sharply as aromatic content continues to increase. 

Non-zeolitic silica-alumina particles of >10 m /g surface area were prepared by steaming commercial FCC catalysts until no zeolite was detected by X-ray diffraction (100% steam, 1600 F, typically 4 hours). 

Anyone who is seriously involved in catalytic cracking, whether as an operator, a catalyst manufacturer, or a researcher, soon learns how severely sodium, vanadium, nickel, iron, and copper act as poisons. In the past, FCC feedstock preparation via vacuum distillation was to a considerable extent, determined by metal carryover. Generally, metal carryover to the fluid unit was limited to 0.1 ppm or less of each of these metals. 

Vanadium was considered much less of a poison with about 1/5 the selectivity detriment of nickel. Iron, especially in the absence of sulfur, was considered even less of a poison. Copper and sodium were of little consequence if proper care was taken to avoid them in FCC feedstock preparation. 

The material balance equations for the FCC unit are easily expressed in terms of the yield equations presented earlier. If F represents the total inlet feed (barrels per day, BPD) to the FCC unit and Y, is the yield of product i as read from Tables 2.3 and 2.4, then the production of product i can be simply obtained by multiplying the feed to the unit by the yield of product i (i.e., FY ). Such material balance equations must be written for all units of a refinery in order to prepare a mathematical... 

In order to develop an ANN model for the FCC process, we use here the same data set as in the previous section (Section 2.4). This data set was divided into two sets, one set for training and one set for testing the neural network. The prepared network model is able to predict the yields of the various FCC products and also the CCR number. During training of the neural network, first, only one hidden layer with five neurons was used. This network did not perform well against a pre-specified tolerance of 10-3. 

The major advantage of the prepared neural network FCC model is that it does not require a lot of input information. In addition, the model can be updated whenever new input-output information for the FCC unit is made available. This can be done by retraining the neural network starting from the old connection weights as an initial guess for the optimization process and by including the new set of data within the overall set used to train the network. 

The main objective in FCC catalyst design is to prepare cracking catalyst compositions which are active and selective for the conversion of gas-oil into high octane gasoline fraction. From the point of view of the zeolitic component, most of the present advances in octane enhancement have been achieved by introducing low unit cell size ultrastable zeolites (1) and by inclusion of about 1-2 of ZSM-5 zeolite in the final catalyst formulation (2). With these formulations, it is possible to increase the Research Octane Number (RON) of the gasoline, while only a minor increase in the Motor Octane Number (MON) has been obtained. Other materials such as mixed oxides and PILCS (3,4) have been studied as possible components, but there are selectivity limitations which must be overcome. 

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