Laboratory-scale Incinerator

TRW Systems, Inc., conducted a laboratory-scale incineration study for the U.S. Army from 1973 to 1975 (9). Eleven individual pesticide formulations and three mixed pesticide formulations containing six different active ingredients (chlordane, 2,4-D, DDT, dieldrin, lindane, and 2,4,5-T) were incinerated in a liquid injection incinerator. The experimental apparatus consisted of a fuel atomizer, combustion chamber, afterburner, quench chamber, and scrubber unit. Destruction efficiencies exceeded 99.99% for a minimum 0.4-s residence time at temperatures above 1000°C with 45 to 60% excess air. 

In addition to these full-scale tests, EPA has initiated a program to conduct extensive intermediate-scale incinerator studies, i.e., studies that would approximate the actual conditions that exist in full-scale incinerators but that at the same time would be close enough to the laboratory studies previously discussed to allow correlation of the results from both scales of operation ( ). The EPA Combustion Research Facility (CRF) has been constructed to conduct this program at the National Center for Toxicological Research (NCTR), Jefferson, Arkansas. 

The authors had already conducted the laboratory scale study and the preliminary pilot plant study, and proposed that "drying-pyrolysis process" (pyrolysis followed by indirect steam drying of dewatered sludge cake) (Fig,-i) could be one of the most economical and feasible alternatives for conventional incineration process. The authors have further conducted the feasibility study on a continuous system of "drying-pyrolysis process to evaluate the performance of the process in pilot scale, and to demonstrate its effectiveness as a thermal processing of sewage sludge. This paper presents the results of this pilot plant study. 

Only a little effort is necessary to reduce solvent 1 demand used during reaction scale-up. The quantity used in the laboratory stage was reduced to 59% in the operation stage (Table 5.1). However, related to substrate 2, 96% of solvent 1 is still used. Thus, 87% of the original quantity of solvent will be fed to the incinerator for disposal, while the recycle rate is only 9.1% (from 96% to 87%, Table 5.1). Considering that there is a factor of five difference in solvent 1 demand between the operation scale and the literature procedure (see the segments Solvent of the mass index, in Figure 5.10), the potential for optimiz-... 

Of course, even without engineering-scale economic and technical drivers, studies of new nuclear solvent extraction technology can and will proceed at academic and national laboratory institutions. Areas for which new technology could be beneficial include, among others, development of extractants that can be readily incinerated detailed information concerning the kinetics of extraction of various solutes and perhaps, development of contactors with very short residence times. Extraction kinetics must be more carefully investigated in the future to be able to take advantage of kinetic differences, especially between the actinides and the fi -transition elements. 

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. 

Contaminated feedstock is heated in an indirectly fired rotary dryer. The vapors are then transported to a gas treatment system via an inert gas such as nitrogen where they are scrubbed and cooled to condense the organics. The carrier gas is reheated and recycled to the dryer. The recovered organics can be reclaimed, used on-site or off-site as fuel, or incinerated. The technology is available in laboratory-, pilot-, and full-scale systems. 

Indeed, in the context of fundamental chemical processes in dilute environments, which are at the heart of this book (i.e. reaction processes in or supported by the gas phase), are combustion processes. As was pointed out in the introductory summary to these application chapters, combustion is all-present in our lives, and is encountered in internal combustion engines, in domestic and large-scale power generation by boilers and furnaces, in incineration of waste, in smelting and glass production, and so on. Not surprisingly, the analysis, monitoring and control of these combustion processes have featured prominently in the transfer of laser chemical methods from the laboratory to the real world. 

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