Multistage reactor

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene—propylene mbbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance (see Elastomers, ETHYLENE-PROPYLENE rubber). This is done by sequential polymerisation of homopolymer polypropylene and ethylene—propylene mbber in a multistage reactor process or by the extmsion compounding of ethylene—propylene mbber with a homopolymer. Addition of high density polyethylene, by polymerisation or compounding, is sometimes used to reduce stress whitening. In all cases, a superior balance of properties is obtained when the sise of the discrete mbber phase is approximately one micrometer. Examples of these polymers and their properties are shown in Table 2. Mineral fillers, such as talc or calcium carbonate, can be added to polypropylene to increase stiffness and high temperature properties, as shown in Table 3. 

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. 

Figure 10-14. The SNIA BPD process for producing caprolactam (1) toluene oxidation reactor, (2) fractionator, (3) hydrogenation reactor (stirred autoclave), (4) multistage reactor (conversion to caprolactam), (5) water dilution, (6) crystallizer, (7) solvent extraction, (8) fractionator.

In the second process the /z-paraffins are partially chlorinated with chlorine gas in a multistage reactor. The resulting product, a mixture of /z-paraffins and chloroparaffins, is fed, together with excess benzene, into a reactor where AlCl3-catalyzed alkylation is performed. The catalyst suspended or dissolved in the crude alkylate is then separated, while the benzene and unconverted ti-paraffins are recovered by distillation and recycled to the previous reaction stages. In the last step of the process, the LAB is separated from the heavy alkylates. This second process needs to be integrated with a chlorine production unit and with an additional industrial transformation plant which makes use of the corrosive HC1 byproduct. 

This is a reversible, endothermic reaction carried out adiabatically in a multistage reactor with either axial or radial flow, and interstage heat transfer for temperature adjustment. 

N. Watanabe, H. Kurimoto, and M. Matsubara. Periodic control of continuous stirred tank reactor III Case of multistage reactor. Chem. Eng. Sci., 39 31-36, 1984. 

Zelmer, R. G., Residence times in continuous multistage reactors. Chem. Eng. Progr. 58, 37 (March 1962). (V)... 

The catalytic distillation reactor is in effect a multistage reactor, where each tray achieves equilibririm at its temperature and composition, with the temperature being lower at the top, where there is more B and higher at the bottom, where there is more C. With a high reflux ratio in the condenser to return any or C to the column, one can attain essentially complete reaction and separation of the products from each other. 

As with the catalytic distillation reactor, the chromatographic reactor functions as a multistage reactor. The chromatographic reactor is essentially a batch reactor, and we need to adapt this configuration into a continuous process to develop a large-scale and economic process. 

Caprolactam is also manufactured from toluene (Fig. 2) by oxidation of toluene (with air) to benzoic acid at 160°C and 10 atm pressure. The benzoic acid is then hydrogenated under pressure (16 atm) and 170°C in a series of continuous stirred tank reactors. The cyclohexane carboxylic acid is blended with oleum and fed to a multistage reactor, where it is converted to caprolactam by reaction with nitrosyl sulfuric acid. 

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. 

Modern, adiabatic multistage reactors may thus become so complex that the question arises whether a... 

Conversion is complete in a single pass. Cyclohexane-carboxylic acid is blended with oleum and fed to a multistage reactor (4) where it is... 

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-... 

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