Reactors, hydrogenation

Figure 8-6. The Hoechst AG process for producing 2-ethylhexanol from n-butyraldehyde (1) Aldol condensation reactor, (2) separation (organic phase from liquid phase), (3) hydrogenation reactor, (4) distillation column.

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.

The sitosterol-sitostanol mixture is cleaned via adsorption on active carbon before entering the hydrogenation reactor. 

Figure 5.3 Schematic of a continuous supercritical hydrogenation reactor...

The hydrogenation reactor consisted of a 1-L Hastelloy C autoclave (Model 464IM, Parr instmment company, Moline Illinois) equipped with a belt-driven, magnetic stirrer (1000 rpm). 

The first reactor is a selective hydrogenation reactor, which product is split into LCN and HCN. The LCN cut is substantially S-free and could be directed to etherification... 

Scheme 3. Chemoselective hydrogenation of imine 8 in a hydrogenation reactor...

Dead-block coders, 7 691 Dead-burned dolomite, 15 27, 53 Dead-end filtration, 11 388 15 827, 829 Dead end hydrogenation reactor, 10 811, 812... 

Unmodified poly(ethyleneimine) and poly(vinylpyrrolidinone) have also been used as polymeric ligands for complex formation with Rh(in), Pd(II), Ni(II), Pt(II) etc. aqueous solutions of these complexes catalyzed the hydrogenation of olefins, carbonyls, nitriles, aromatics etc. [94]. The products were separated by ultrafiltration while the water-soluble macromolecular catalysts were retained in the hydrogenation reactor. However, it is very likely, that during the preactivation with H2, nanosize metal particles were formed and the polymer-stabilized metal colloids [64,96] acted as catalysts in the hydrogenation of unsaturated substrates. 

Removal of H2S and acid gases from the hydrogenation reactor process stream and also from the raw gases obtained from gasification of the heavy residual is required. The incentive for H2S removal and recovery of elemental sulfur in this case is environmental. 

There is not information about multiphase slurry reactors at high solid loading. Murthy [16] suggests to use the following equations for hydrogenation reactors. Heat transfer to jacket (process side coefficient) is given by ... 

Concerning activity, most studies focus on intrinsic (chemical) kinetics, with little consideration to the apparatus and its possible physical limitations. In fact,the design and selection of a catalytic hydrogenation reactor (hydrogenator) is not a trivial problem at all, owing to the broad range of process conditions encountered. 

The size of the bubbles produced in the reactor and the gas volume fraction will depend on the agitation conditions, and the rate at which fresh hydrogen is fed to the impeller, as shown in Fig. 4.20. (Some hydrogenation reactors use gas-inducing impellers to recirculate gas from the head-space above the liquid while others use an external compressor.) For the purposes of the present example, the typical values, db = 0.8 mm and eg m 0.20, will be taken. Also dependent to some extent on the agitation conditions are the values of the transfer coefficients kL and k, although these will depend mainly on the physical properties of the system such as the viscosity of the liquid and the diffusivity of the dissolved gas. The values taken here will be kL = 1.23 x 10 5 m/s and k, = 0.54x 10"3 m/s. 

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