Transpired-Wall Reactors

Analytical solutions are possible in special cases. It is apparent that transpiration will lower the conversion of the injected component. It is less apparent, but true, that transpired wall reactors can be made to approach the performance of a CSTR with respect to a transpired component while providing an environment similar to piston flow for components that are present only in the initial feed. 

Use Scalable Heat Transfer. The feed flow rate scales as S and a cold feed stream removes heat from the reaction in direct proportion to the flow rate. If the energy needed to heat the feed from to Tout can absorb the reaction exotherm, the heat balance for the reactor can be scaled indefinitely. Cooling costs may be an issue, but there are large-volume industrial processes that have Tin —40°C and Tout 200°C. Obviously, cold feed to a PFR will not work since the reaction will not start at low temperatures. Injection of cold reactants at intermediate points along the reactor is a possibility. In the limiting case of many injections, this will degrade reactor performance toward that of a CSTR. See Section 3.3 on transpired-wall reactors. 

Piston Flow in Contact with a CSTR. A liquid-phase reaction in a spray tower is conceptually similar to the transpired-wall reactors in Section 3.3. The liquid drops are in piston flow but absorb components from a well-mixed gas phase. The rate of absorption is a function of as it can be in a transpired-wall reactor. The component balance for the piston flow phase is... 

Under joint sponsorship by the U. S. Army Research, Development and Engineering Center (ARDEC) and the U. S. Department of Energy (DOE), a bench-scale transpiring wall reactor was developed by Sandia National Laboratories, FWDC, and GenCorp Aerojet. The reactor, which uses SCWO, was designed to treat military and other liquid wastes. A commercial application of the technology is in use to destroy munitions, colored smokes, and dyes. SWCO may also provide a viable alternative to incineration for the destruction of chemical weapons. 

Transpired wall reactors Nonideal tubular reactors may have concentrations that vary in the r and 0 directions... 

It is important to note that most large-scale SCWO reactors are designed to be turbulent flow. In addition, some of the reactors (e.g., transpiring wall reactor) are not possible to scale down for laboratory-scale experiments. The method given here is a generic approach for understanding the reaction kinetics of pollutants under SCWO conditions. 

Figure 11 Transpiring wall reactor by Foster Wheeler Corporation. (From Ref. 119.)... 

U.S. Army Transpiring wall reactor Colored smokes and dyes 600°C, 10 g/s... 

U.S. Navy Combination of down-flow and transpiring wall reactors Black water, gray water, paint, solvent, oil, etc. 40 g/s... 

Fig. 1 Principles of the most outstanding SCWO reactor configurations a) tubular reactor developed at the university of Austin, Texas / /, commercialized by EWT, operated in Huntsville,Texas 111, capacity 5 gpm b) vessel reactor, MODAR Inc., Massachusetts /3/ c) transpiring wall reactor, Summit Research Corp., Santa Fe, New Mexico /4/ filmcooled coaxial hydrothermal burner developed at the ETH Zurich, Switzerland 15/...

Summit Research/ 1992-present Transpiring wall reactor ... 

Eoster Wheeler 1993-2003 Transpiring wall reactor Aerojet Gencorp Corp.,... 

P. J. Crooker, K. S. Ahluwalia and Z. Fan, Supercritical Water Oxidation of Chemical Weapon Agents by Transpiring Wall Reactor, Proceedings of the International Conference on Incineration and Thermal Treatment Technologies, Philadelphia, PA, May, 2001. T. G. McGuinness, Supercritical Oxidation Reactor, U.S. Patent 5,384,051, January 24, 1995. 

Transpired-Wall Reactors 123 SOLUTION With constant density, Equation 3.49 becomes... 

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