Deactivation reactors

Kinetic Rate Lam y/Vfateriat Balance reaction/deactivation/ reactor design equation, heat/mass transpat/ fluid-flow model,... 

The energetics from the RDM, the propellant grinder, and COINS operations are hydrolyzed to completion in Area 200 within the propellant collection reactor (PCR) and the energetics/propellant deactivation reactor (EPDR). The PCR is used as a collection vessel for the material processed by the propellant... 

As the catalyst deactivates, reactor inlet temperature must be increased to maintain the target octane. A typical temperature profile as a function of process stream time is shown in Fig. 7. The temperature increase further... 

An alternative method is to move the reactor core in one piece, which is also described in the DOE environmental impact statement (EIS) (1993) and which is the preferred transport method for the eight deactivated reactors at the Hanford Site. However, because the N Reactor sits on a pedestal and the thermal and radiation shielding are not integrated into the core structure, the preferred option may not be feasible. 

In many reactions, sintering is as important as chemical deactivation. For those reactions affected by both sintering and chemical deactivation, reactor point effectivenesses have been developed for use in reactor design, which is treated in Part III. 

This was a Hquid-phase process which used what was described as siUceous zeoUtic catalysts. Hydrogen was not required in the process. Reactor pressure was 4.5 MPa and WHSV of 0.68 kg oil/h kg catalyst. The initial reactor temperature was 127°C and was raised as the catalyst deactivated to maintain toluene conversion. The catalyst was regenerated after the temperature reached about 315°C. Regeneration consisted of conventional controlled burning of the coke deposit. The catalyst life was reported to be at least 1.5 yr. 

Propylene, butylenes, or amylenes are combiaed with isobutane ia the presence of an acid catalyst, eg, sulfuric acid or hydrofluoric acid, at low temperatures (1—40°C) and pressures, 102—1035 kPa (1—10 atm). Sulfuric acid or hydrogen fluoride are the catalysts used commercially ia refineries. The acid is pumped through the reactor and forms an emulsion with reactants, and the emulsion is maintained at 50% acid. The rate of deactivation varies with the feed and isobutane charge rate. Butene feeds cause less acid consumption than the propylene feeds. 

Shift Conversion. Carbon oxides deactivate the ammonia synthesis catalyst and must be removed prior to the synthesis loop. The exothermic water-gas shift reaction (eq. 23) provides a convenient mechanism to maximize hydrogen production while converting CO to the more easily removable CO2. A two-stage adiabatic reactor sequence is normally employed to maximize this conversion. The bulk of the CO is shifted to CO2 in a high... 

For fixed-bed reactors containing rapidly deactivating catalysts, the scheduled changes ia operating variables to accommodate activity loss can have a marked effect on mn length. This is exemplified by acetylene hydrochiorination to produce vinyl chloride ia tubular fixed-bed reactors. Steel reactors,... 

In the low temperature process, the slurry is heated to 105—108°C and held at temperature for 5—10 minutes. The resulting 1—2 DE hydrolyzate is flashed to atmospheric pressure and held at 95—100°C for one to two hours in a batch or continuous reactor. Because the enzyme is not significantly deactivated at the first-stage temperature, a second enzyme addition is not needed. This process is used woddwide throughout the starch-based sweetener industry and has been judged the most efficient process for dextrose production. 

Because HCl is constandy present in most parts of the equipment, corrosion is always a potential problem. Chlorine and benzene, or any recycled material, must be free of water to trace amounts to prevent corrosion and deactivation of the catalyst. The reactor product contains HCl and iron. In some plants, the product is neutralized with aqueous NaOH before distillation. In others, it is handled in a suitably-designed distillation train, which includes a final residue from which FeCl can be removed with the high boiling tars. 

The heat released from the CO—H2 reaction must be removed from the system to prevent excessive temperatures, catalyst deactivation by sintering, and carbon deposition. Several reactor configurations have been developed to achieve this (47). 

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