Packed-bed reactor operation

For a packed-bed membrane reactor (PBMR) the membrane is permselective and removes the product as it is formed, forcing the reaction to the right. In this case, the membrane is not active and a conventional catalyst is used. Tavolaro et al. [45] demonstrated this concept in their work on CO2 hydrogenation to methanol using a LTA zeolite membrane. The tubular membrane was packed with bimetallic Cu/ZnO where CO2 and H2 react to form EtOH and H2O. These condensable products were removed by LTA membrane which increased the reaction yield when compared to a conventional packed bed reactor operating under the same conditions [45]. 

A packed-bed reactor operating nnder plng-flow conditions is theoretically the most... 

The goal of this investigation was the development of a suitable reactor model for propylene oxidation in an industrial-size packed-bed reactor operated under industrially relevant conditions (4). 

In the third type of gas-liquid-solid reaction, only two of the three phases take part into the reaction, the third phase being an inert phase. This type of reaction can be further subdivided into three catagories. Some reactions are strictly gas liquid reactions, but they are often carried out in packed-bed reactors operating under countercurrent-flow conditions. Here, the solid imparts momentum transfer and allows better gas-liquid contact and gas-liquid interfacial mass... 

Ethylene and oxygen are fed in stoichiometric proportions to a packed-bed reactor operated isothermally at 260°C. Ethylene is fed at a rate of 0.30 lb mol/s at a pressure of 10 atm. It is proposed to use 10 banks of 11-in.-diameter schedule 40 tubes packed with catalyst with 100 tubes per bank. Consequently, the molar flow rate to each Qibe is to be 3 X lO " Ib inol/s. The properties of the reacting fluid are to be considered identical to those of air at this temperature and pressure. The density of the j -itL-catalyst particles is 120 Ib/ft and the bed void fraction is 0.45. The rate law is... 

Reaction (la) occurs quite easily, whereas reaction (lb) is slower and can be accelerated using an add scavenger such as a tertiary amine or an inorganic base, e.g., NaOH. While making the carbonate, the amount of alcohol and the reactor residence time are increased. The continuous production of methyl carbonate has been reported in a 1973 French patent. Here, methyl chloroformate and methanol are fed continuously into a packed-bed reactor operating with a bottom to top temperature gradient of 72-127°C. HCl is drawn off the head and dimethylcarbonate (99%) is withdrawn from the base. 

Purwono, S. Budman, H. Hudgins, R.R. Silveston, P.L. Matros, Y.S. Runway in packed bed reactors operating with periodic flow reversal. Chem. Eng. Sci. 1994, 49, 5473-5487. 

Packed-bed reactor operation was used to test the stability of the CVD-prepared Ti/Si02 catalysts. For simplification, the reaction used was the epoxidation of 1-ocfene with TBUP. It is much easier and simpler to carry out 1-octene epoxidation (than propylene epoxidation) in a packed-bed reactor because 1-octene (boiling point, b.p. = 122 °C) is a liquid under the reaction temperature (110 °C). No decay of 1,2-epoxyoctane yield was observed during 12 h of continuous operation with the packed-bed reactor, therefore, the CVD-prepared Ti/Si02 catalysts were stable under continuous operation conditions. 

For the packed-bed reactor operation. Fig. 14.3 and row 5 of Table 14.1 show TBHP conversion, 1,2-epoxyoctane yield, and selectivity versus TiC deposition time. Batch reactor data obtained for the reaction between 1-octene and TBHP are shown rn row 6 of Table 14.1. Both the packed-bed reactor data and the batch reactor data show that epoxide yield and epoxide selectivity increased with the increase in deposition time. The maximum 1,2-epoxyoctane selectivity obtained with the packed-bed reactor was 98.5% (for the catalyst prepared with 2.5 h deposition time), which was slightly higher than that (selectivity = 94.5%)... 

Rea RTD data from an industrial packed bed reactor operating under poor operation. [3rd Ed. P13-5]... 

Figure 9.15 Packed bed reactor operating regimes (Kolev, 2006).

The most important "competitor" to the sluiry reactor for solid/liquid/gas systems is the packed bed reactor operated widi two-phase flow. The main advantage of this type of reactor is that the catalyst remains in the reactor. Mostly porous catalyst particles are used with a size of a few mm. The two-phase flow of gas and liquid can be realized in several ways ... 

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