Temperature effects catalytic cracking

Zhao X, Roberie TG. ZSM-5 additive in fluid catalytic cracking. 1. Effect of additive level and temperature on light olefins and gasoline olefins. Ind Eng Chem Res 1999 38(10) 3847-53. 

A mixture of monolauryl phosphate sodium salt and triethylamine in H20 was treated with glycidol at 80°C for 8 h to give 98% lauryl 2,3-dihydro-xypropyl phosphate sodium salt [304]. Dyeing aids for polyester fibers exist of triethanolamine salts of ethoxylated phenol-styrene adduct phosphate esters [294], Fatty ethanolamide phosphate surfactant are obtained from the reaction of fatty alcohols and fatty ethanolamides with phosphorus pentoxide and neutralization of the product [295]. A double bond in the alkyl group of phosphoric acid esters alter the properties of the molecule. Diethylethanolamine salt of oleyl phosphate is effectively used as a dispersant for antimony oxide in a mixture of xylene-type solvent and water. The composition is useful as an additive for preventing functional deterioration of fluid catalytic cracking catalysts for heavy petroleum fractions. When it was allowed to stand at room temperature for 1 month it shows almost no precipitation [241]. 

Performance Analysis. In order to determine the effect of hydrotreating on catalytic cracking performance, the above feedstocks were evaluated at a low severity cracking condition (catalyst-to-oil ratio of 6.0 and reactor temperature of 910° F) and a high severity cracking condition (catalyst-to-oil of 8.0 and reactor temperature of 1010° F). The results from the catalytic cracking of these feedstocks (shown in Tables I and II) are shown in Tables III through V. The results presented in these tables are... 

Table VI. Effect of Cracking Temperature in Fluid Catalytic Cracking Using Silica-Alumina Catalyst...

Gravimetric Results of Catalytic Cracking. Experiments were conducted to assess the effects of temperature, cat-to-oil ratio, and feedstock composition. In addition to the effect of variables on product yields, it was also important to identify the relative influence of thermal reactions, since free-radical reactions may adversely affect product quality. A series of experiments was conducted in the temperature range of 412°-415°C because this is the temperature of maximum increase in production from thermal cracking and catalytic vs. thermal effects are more easily discernible at this temperature. 

A series of experiments were conducted at about 460°C. This temperature is closer to the temperature used in commercial units operating at low severity. Testing at moderate conversions minimizes the thermal effects and tends to maximize the differences experienced by a change in variables other than temperature. Results are given in Table V and show that catalytic cracking (Runs Bt(3,4, 5)) produces yields similar to or better than coking (Bt(ll)). A single run at 500°C (Bt(16)) resulted... 

The distillate and residue obtained by high vacuum-distillation of catalytic cracking bottoms were converted into highly aromatic and anisotropic pitches. We used a two-stage high temperature process at 400°C. The effect of various process parameters on pitch composition and rheology was investigated. 

Further, each catalyst had a significant effect on the position of double bonds and olefinic content. The catalyst also affects the other properties of liquid fraction such as density. A decrease in density of the liquid indicates low average molecular weight. They also observed that the pour points were lower with ZSM-5 and FCC catalyst than with CRT. Maximum distillation temperatures of liquid products were lower after catalytic cracking than for thermal cracking. 

The effects of temperature on catalytic cracking of various plastics over FZ-W catalyst have been investigated [84] and are shown in Table 28.8. In the temperature range 300-350°C, the highest yield of oil products was achieved. When the temperature is below 300°C, yields of residue and noncondensed gases are low, large amount of feedstocks were left uncracked Above 350°C, the yields of residue and noncondensed gas increased, and the amount of oil products obtained decreased relatively. 

Suib et at. (25, 254) reported the different effects of nickel and vanadium on the catalytic activity and selectivity for the fluid catalytic cracking by a photoluminescence technique and showed that the method is useful in predicting the catalyst deactivation caused by the deposition of metals on surfaces. The activity of the catalyst decreases monotonically with increasing vanadium content. With 1.5 wt% of V, the catalystad lost most of its activity, and with 2.0 wt% of V it became almost completely inactive. Such a deactivation of the catalyst was irreversible, with the extent being closely associated with the surface area covered with vanadium. Moreover, the extent of the deactivation was found to depend on the aging temperature, which was accelerated when aging was carried out under the same conditions normally sized in hydrothermal reactions. 

Figure 1. Effect of pretreatment temperature on catalytic cracking of cumene and on hydrogen-deuterium exchange...

Refining of the catalytically cracked aviation base stock was at first done with sulfuric acid, merely to remove unsaturates (133). However, it was found that passing the raw aviation fraction a second time over the cracking catalyst (catalytic re-treating) resulted in a product with less olefins, more aromatics, and improved response to tetraethyllead, and thus decreased sharply the proportion of alkylate required in the aviation blend (51). These effects are illustrated in Table VII. The effect of retreating a naphtha from a high-temperature first-pass operation is shown in Table VIII, and the quality of the aviation base stock is compared... 

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