Flow-through reactor

The flow out of the reactor passes through a restriction (control valve) inW another vessel which is held at a constant pressure Pp (absolute). The outflow will vary with the pressure and the composition of the reactor. Flows through control valves are discussed in more detail in Part III here let us use the formula... 

To further control the runaway risk, the reaction temperature is kept at 230—250°F by regulating the reactor flow-through rate. At chat temperature, only about 25% of the cumene is converted to phenoL The stream coming out of the bottom of the oxidizing vessel is 25% cumene hydroperoxide and 75% unconverted cumene. 

The product mixture leaving the reactor flows through heat exchangers in order to heat the reactant mixture to the desired temperature. Subsequently, the mixture is further cooled and raw methanol condenses while the unconverted synthesis gas is recycled to the reactor. The raw methanol is purified by distillation. 

In separation processes and chemical reactors, flow through cylindrical ducts filled with granular materials is important. In such systems conduction, convection, and radiation all contribute to the heat flow, and thermal conduction in axial ke x and radial ke r directions may be quite different, leading to highly anisotropic thermal conductivity. For a bed of uniform spheres, the axial and radial elements are approximated by... 

The effluent stream from the reactors flowed through a condenser and cylinder where liquid products were separated and collected. The exit gas pressure was reduced to 1 atm, and products were sampled on-line to measure the concentrations of CO, CO2, N2, and CH4, Finally, the effluent was discharged to the outside atmosphere via a wet test meter. The compositions of liquid products were measured by gas chromatography. The activity is reported in terms of the methanol yield. 

Flow of fluids through packed beds of granular particles occurs frequently in chemical processes. Examples are flow through a fixed-bed catalytic reactor, flow through a filter cake, and flow through an absorption or adsorption column. An understanding of flow through packed beds is also important in the study of sedimentation and fluidization. 

Gas and liquid are mixed before entering the reactor bed in a gas-liquid chamber 17 at the inlet of the reactor. The gas leaving the reactor flows through a condenser 18, where evaporated solvent is condensed, and then to the gas-liquid separator 19. The condensed solvent is collected in a separate buffer vessel 20 and returned to the reactor if necessary, the gas leaves the system through a backpressure valve controlling the pressure in the system. The volumetric flow of the effluent gas is measured with a gas meter 21. 

The product stream exiting the reactor flowed through an analytical sampling valve. Between analyses, the analytical system circulated the transfer solvent. 

Because all the heat leaving the reactor flows through the walls and into the coolant, the capacities of reactants, walls, and coolant interact. But in view of the slight heat capacity of the bulb, its time constant does not significantly interact with the others. Basically the process is four-capacity plus dead-time. 

A solution of trifluoroacetic acid in toluene was found to be advantageous for cydization of pyruvate hydrazoncs having nitro substituents[4]. p-Toluene-sulfonic acid or Amberlyst-15 in toluene has also been found to give excellent results in preparation of indole-2-carboxylale esters from pyruvate hydra-zoiies[5,6J. Acidic zeolite catalysts have been used with xylene as a solvent to convert phenylhydraziiies and ketones to indoles both in one-flask procedures and in a flow-through reactor[7]. 

The hydrocarbon gas feedstock and Hquid sulfur are separately preheated in an externally fired tubular heater. When the gas reaches 480—650°C, it joins the vaporized sulfur. A special venturi nozzle can be used for mixing the two streams (81). The mixed stream flows through a radiantly-heated pipe cod, where some reaction takes place, before entering an adiabatic catalytic reactor. In the adiabatic reactor, the reaction goes to over 90% completion at a temperature of 580—635°C and a pressure of approximately 250—500 kPa (2.5—5.0 atm). Heater tubes are constmcted from high alloy stainless steel and reportedly must be replaced every 2—3 years (79,82—84). Furnaces are generally fired with natural gas or refinery gas, and heat transfer to the tube coil occurs primarily by radiation with no direct contact of the flames on the tubes. Design of the furnace is critical to achieve uniform heat around the tubes to avoid rapid corrosion at "hot spots."... 

Characteristic of fluidized bed reactors is the large wind box to equalize pressure. This is a primary requirement to get even flow through the bed. The expanding shell at the upper part is there to retain as much solid as possible in the reactor. 

Fig. 6. Breakthrough curves for aqueous acetone (10 mg 1" in feed) flowing through exnutshell granular active carbon, GAC, and PAN-based active carbon fibers, ACF, in a continuous flow reactor (see Fig. 5) at 10 ml min" and 293 K [64]. C/Cq is the outlet concentration relative to the feed concentration. Reprinted from Ind. Eng. Chem. Res., Volume 34, Lin, S. H. and Hsu, F. M., Liquid phase adsorption of organic compounds by granular activated carbon and activated carbon fibers, pp. 2110-2116, Copyright 1995, with permission from the American Chemical Society.

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