Vertical reactor

In the one-stage process (Fig. 2), ethylene, oxygen, and recycle gas are directed to a vertical reactor for contact with the catalyst solution under slight pressure. The water evaporated during the reaction absorbs the heat evolved, and make-up water is fed as necessary to maintain the desired catalyst concentration. The gases are water-scmbbed and the resulting acetaldehyde solution is fed to a distUlation column. The tad-gas from the scmbber is recycled to the reactor. Inert materials are eliminated from the recycle gas in a bleed-stream which flows to an auxdiary reactor for additional ethylene conversion. 

From Acetylene. Although acetaldehyde has been produced commercially by the hydration of acetylene since 1916, this procedure has been almost completely replaced by the direct oxidation of ethylene. In the hydration process, high purity acetylene under a pressure of 103.4 kPa (15 psi) is passed into a vertical reactor containing a mercury catalyst dissolved in 18—25% sulfuric acid at 70—90°C (see Acetylene-DERIVED chemicals). 

Figure 1 Illustrates two general MOCVD reactor configurations, the horizontal reactor and the axlsymmetrlc vertical reactor. The reactant gas (ASH3, Ga(CH3)3 and Al( 013)3) enters cold and heats up as It fiows toward the substrate where a solid film of AlGaAs Is being deposited. The chemical transformations Involved In the deposition process may occur both In the gas phase and on the surface of the growing film.

Figure 1. Two typical MOCVD reactor configurations (a) horizontal reactor (b) vertical reactor.

The vertical reactor (Figure lb) Is assumed to be axlsymmetrlc which... 

The vertical reactor simulations reported In this paper typically Involved 14,000 unknowns and took 25 CPU seconds per Newton Iteration on a Cray-2. The tracing of a complete family of solutions for one parameter (e.g. susceptor temperature) cost approximately 25 CPU minutes. The latter number underscores the advantage of using supercomputers to understand the structure of the solution space for physical problems which often Involve many parameters. 

Figure 7. Reduced Nusselt number for mass transfer to the substrate In a vertical reactor for varying Inlet flow rate and susceptor temperature.

De Laval Centripure A continuous soapmaking process. Fat and aqueous sodium hydroxide are fed countercurrently to a vertical reactor through which much of the product is continuously recirculated, thus emulsifying the reactants. 

At the heart of the UOP HF alkylation unit is a vertical reactor-heat exchanger, shown in Fig. 14. The isobutane-alkene mixture enters the shell of the reactor through several nozzles, and HF enters at the bottom of the reactor. The reaction heat is removed by cooling water, which flows through cooling coils inside the reactor. After phase separation in the settler, the acid is recycled to the reactor. The hydrocarbon phase together with a slipstream of used acid and makeup isobutane is sent to the isostripper , where the alkylate product, n-butane, and isobutane are separated. The isobutane is recycled to the reactor. During normal... 

As shown in Figure 16-2, high purity ethylene (99.7%) and oxygen (99.0%) are fed under pressure (100 psi) to a vertical reactor containing the aqueous catalyst solution. Reaction temperature is maintained at 250-275°F. Because the reaction is exothermic, heat liberated is partially removed by vaporizing the water present in the reactor. Malceup water is continuously fed to the reactor to maintain proper catalytic solution concentration. 

For these situations the performance equations could more usefully be written differently. With Uq as the superficial gas velocity (velocity if solids are absent) through the vertical reactor, Fig. 18.11 shows what happens in a thin slice through the reactor. A steady-state material balance gives... 

A combined Merox process operation is also utilized to sweeten fuel. This countercurrent method involves feeding fuel into the bottom of a vertical reactor and feeding caustic and catalyst from the top. Mercaptans are extracted into the caustic and react to form disulfides. The caustic and disulfides are later separated. The following reactions occur during the Merox sweetening process ... 

After each growth cycle, the reactors must be opened, the wafers removed, and the lower portion of the reactor physically cleaned. The lower quartz reactor and the bottom plate (base plate) are scraped clean using a metal tool, and the particulate material (mixture of GaAs, GaAsP, arsenic oxides and phosphorus oxides) is collected in a metal container positioned below the vertical reactor. 

D.I. Fotiadis, S. Kieda, and K.F. Jensen. Transport Phenomena in Vertical Reactors for Metalorganic Vapor Phase Epitaxy I. Effects of Heat Transfer Characteristics, Reactor Geometry, and Operating Conditions. J. Cryst. Growth, 102 441—470,1990. 

Most furnace black reactors are arranged horizontally. They can be up to 18 m long with an outer diameter of up to 2 m. Some vertical reactors are used especially for the manufacture of certain semireinforcing blacks [4.12] (Fig. 51). For further reactors, see [4.13]. 

Figure 51. Vertical reactor for manufacturing semireinforcing blacks...

HF alkylation reactors have undergone more drastic changes than H2S04 reactors. In the middle 1950 s a Stratco contactor similar to that for H2S04 alkylation was used. Later a vertical reactor was developed in which the reactants were bubbled up through liquid HF. Cooling was... 

Figure 1. Typical CVD reactor configurations, (a) Horizontal reactor, (b) vertical reactor, (c) barrel reactor, (d) pancake reactor, (e) cross-flow LPCVD reactor, and (f) conventional multiple-wafer-in-tube LPCVD reactor.

Flow Patterns and Film Properties. Uniform film thickness and sharp interfaces can be realized in vertical reactors by creating a boundary layer... 

Vertical reactor or stagnation point flow reactor at atmospheric and reduced pressure conditions... 

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