Effect of Regeneration Temperature

Table IX shows the effect of regenerator temperature on the relative fractional ZSM-5 replacement rate required to achieve a 1 RON boost. The model prediction shows that ZSM-5 is relatively insensitive to FCC regenerator temperature.

Figure 4. Effect of regenerator temperature on the Davison SOx Index for a blend of DA-250 + 10% Additive R + 0.37% CP-3. The blend was steam-deactivated at 1350 F, 100% steam, 15 psig, 8 hrs.

In the present work, characterization and catalytic studies are performed at the laboratory scale to better understand the deactivation and the regeneration process in this industrial case. Additionally, the effect of regeneration temperature over catalytic performance of samples regenerated are evaluated. 

For the preparation of spray-dried polyelectrolyte complexes, the polyanion was dissolved in dilute NH4HCO3 solution and mixed with the chitosan carbamate solution just before spray-drying. The excess NH4HCO3 decomposed thermally between 60 and 107 °C on the other hand, the carbamate function released carbon dioxide under the effect of the temperature at which the spray-drier was operated, thus regenerating chitosan at the moment of the polyelectrolyte microsphere formation (Fig. 5). 

Figure 7. Effect of regeneration with air on TPO profiles. Thick and thin lines correspond to samples submitted once and twice to reaction conditions, respectively. Reaction temperatures as indicated.

Figure 4. The effect of regenerations on pressure drop ciu es. For all runs, the same EX47 trap was used. The filters were regenerated after each run. The oven temperature was 650 K, the additive concentration 100 ppm.

The effect of riser temperature on the diolefin content on FCCU butanes is correlated in Figure 6-3. One refiner also reported that an increase in regenerator temperature from 1,280°F to 1,320°F doubled the diolefin content of the alkylation unit feed. ... 

Salvador F, Sanchez-Jimdnez C. Effect of regeneration treatment with liquid water at high pressure and temperature on the characteristics of three commercial activated carbons. Carbon 1999 37 577-583. 

The effects of pH, temperature, chloride concentration, complex concentration, irradiation, and added cations on the stability of hexachloroiridate(IV) solutions have been reviewed, in connection with the use and regeneration of this complex as a catalyst. This chapter includes a large multistep and multi-component scheme. It does not give any rate constants, but gives several references to kinetic data. ... 

The metal matrix of a regenerator undergoes a cyclic variation in temperature because of its less than infinite heat capacity. Fortunately, however, the temperature excursion of the extreme ends of the matrix is much less than that of the central portion, a fact which minimizes the effect of this temperature variation upon thermodynamic efficiency. At very low temperatures the heat capacity of all metals falls to a negligibly small value and it becomes impractical to utilize thermal regenerators. Regenerators constructed of lead have been found to be useful at temperatures as low as 14°K. 

Primary alkanolamine solutions require a relatively high heat of regeneration. Also excessive temperatures or localized overheating in reboilers cause the MEA to decompose and form corrosive compounds. An inhibitor system, such as the Amine Guard system developed by Union Carbide, is an effective method of corrosion control (52). Inhibitors permit the use of higher (25—35%) concentration MEA solutions, thus allowing lower circulation rates and subsequendy lower regeneration duty. 

A good catalyst is also stable. It must not deactivate at the high temperature levels (1300 to 1400°F) experienced in regenerators. It must also be resistant to contamination. While all catalysts are subject to contamination by certain metals, such as nickel, vanadium, and iron in extremely minute amounts, some are affected much more than others. While metal contaminants deactivate the catalyst slightly, this is not serious. The really important effect of the metals is that they destroy a catalyst s selectivity. The hydrogen and coke yields go up very rapidly, and the gasoline yield goes down. While Zeolite catalysts are not as sensitive to metals as 3A catalysts, they are more sensitive to the carbon level on the catalyst than 3A. Since all commercial catalysts are contaminated to some extent, it has been necessary to set up a measure that will reflect just how badly they are contaminated. 

These metals, when deposited on the E-cat catalyst, increase coke and gas-making tendencies of the catalyst. They cause dehydrogenation reactions, which increase hydrogen production and decrease gasoline yields. Vanadium can also destroy the zeolite activity and thus lead to lower conversion. The deleterious effects of these metals also depend on the regenerator temperature the rate of deactivation of a metal-laden catalyst increases as the regenerator temperature increases. 

One of the advanced concepts for capturing CO2 is an absorption process that utilizes dry regenerable sorbents. Pure sodium bicarbonate from Dongyang Chemical Company and spray-dried sorbents were used to examine the characteristics of CO2 reaction in a flue gas environment. The chemical characteristics were investigated in a fast fluidized reactor of 0.025 m i.d., and the effects of several variables on sorbent activity, including gas velocity (1.5 to 3.5 m/s), temperature (40 to 70 °C), and solid concentration (15 to 25 kg/m /s)], were examined in a fast fluidized-bed. Spray-dried Sorb NX30 showed fast kinetics in the fluidized reactor. 

Thus, the model proposed explains the effect of CO on electric conductivity of several oxides only in case when oxygen is present in ambient volume which was observed in numerous experiments. Accordingly, the fact of existence of relatively narrow temperature interval in which an adsorbent is sensitive to CO becomes clear. This can be linked with the fact that if the operational temperature To is small the reaction products (in case of CO this is CO2) cannot get desorbed (see expression (2.80)), i.e. regeneration of the centers of oxygen adsorption is not feasible. If Tq is very high both adsorption of oxygen and reducing gas should be ruled out. 

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