Multistage reactor system

Ammonium Phosphates. In the manufacture of ammonium phosphates, an atmosphere of ammonia may need to be maintained because the partial pressure of ammonia rises rapidly as either the temperature or the NH2/P20 mole ratio of the reaction mass increases. Phosphoric acid reacts quickly with ammonia vapor and is used in multistage reactor systems as a scmbber fluid to prevent NH emissions and recover ammonia values. For example, H PO scmbbing of coke-oven off-gases produces ammonium phosphates of relatively good purity. 

The reaction part of the process is shown schematically in Figure 1. It consists of feeding a mixture of olefin, sythesis gas and recycle (plus makeup) catalyst to a multistage reactor system. The reactor product is cooled, degassed and fed to vacutm evaporators for crude alcohol recovery. 

Description In the Classic process, EB is catalytically dehydrogenated to styrene in the presence of steam. The reaction is carried out at high temperature under vacuum. The EB (fresh and recycle) and primary steam are combined with superheated steam, and the mixture is dehydrogenated in a multistage reactor system (1). An interheater reheats the process gas between stages. Reactor efflu-... 

Fig. 9 Typical conversion vs. temperature profile for SO2 oxidation in a multistage reactor system.

Fig. 10 shows a typical SO2 multistage reactor system manufactured by Zieren-Chemiebau. This particular design has feed-effluent heat exchangers and cold-shot interstage cooling. 

Note that for very high specifie reaetion rates, a multistage reactor system is not feasible for the numerical case studied. This is because the reactor size gives a transfer area that is so small that the required jacket temperature is lower than the temperature of the available cooling water. Refrigeration could be used or heat transfer area rnnlrl h<= im- r(= acr rt ac... 

Hydrocracking—uses a multistage reactor system to boost yields of gasoline from crude oil. 

The scheme of commercial methane synthesis includes a multistage reaction system and recycle of product gas. Adiabatic reactors connected with waste heat boilers are used to remove the heat in the form of high pressure steam. In designing the pilot plants, major emphasis was placed on the design of the catalytic reactor system. Thermodynamic parameters (composition of feed gas, temperature, temperature rise, pressure, etc.) as well as hydrodynamic parameters (bed depth, linear velocity, catalyst pellet size, etc.) are identical to those in a commercial methana-tion plant. This permits direct upscaling of test results to commercial size reactors because radial gradients are not present in an adiabatic shift reactor. 

Equation (6.14) is used for the temperature of gas in the tubes of the intermediate heat exchanger used in the multistage adiabatic reactor system. Heat is transferred from the hot gas to saturated water on the shell side generating steam at temperature Tst. The overall heat transfer coefficient Uux is constant and is equal to 0.227 kJ s-1 m-2 K-1. The heat transfer area per volume Ahx/Vhx is 157 m2/m3 ... 

Figures 6.5-6.8 show the control structures used for the four alternative tubular reactor systems. In Figures 6.6 and 6.7 (the multistage adiabatic systems with interstage...

MULTISTAGE ADIABATIC REACTOR SYSTEM WITH INTERSTAGE COOLING 299... 

Figure 6.16 shows results for a 20% increase in recycle flow FR. The production rate is changed by only 10%, which is less than observed for the single adiabatic reactor. Thus the recycle flowrate is not an effective manipulating variable for changing the production rate in this multistage adiabatic reactor system with intermediate cooling. 

A continuous operation using a multistage stirred-tank reactor system and hydrogen sulfide recycling by absorption in the sodium tungstate solution substantially reduces the amount of sulfuric acid. 

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