Incinerator controlled-air

In 1981 the Los Alamos National Laboratory investigated for EPA the thermal destruction of wooden boxes treated with penta-chlorophenol (PCP). The incineration system consisted of a dual-chamber, controlled-air incinerator, a spray quench column, a venturi scrubber, and a packed-column acid gas absorber (11). Destruction efficiencies for PCP exceeded 99.99% for combustion chamber temperatures above 980°C, 20% excess air, and a retention time greater than 2.5 s. For these conditions, TCDD and... 

Stretz, L. A. Vavruska, J. S. "Controlled Air Incineration of PCP-Treated Wood," Los Alamos National Laboratory/U.S. Environmental Protection Agency lERL/CI Incineration Research Branch, U.S. EPA Interagency Agreement AD-89-F-1-539-0, undated. 

Most central disposal facilities utilize mass-burning systems other facilities use controlled air incineration techniques. Mass-burning technology is described in more detail in the following problem (MUN.IO). 

Compare controlled-air incineration and rotary kiln incineration for the central facility. 

Controlled-air incinerators have a lower capital cost since they do not normally require air pollution control equipment (unless acid gas emissions are excessive). But since this facility must comply with new stringent regulations and acid gas emissions may be excessive, a rotary kiln system may be more advantageous. 

Since this facility is large compared to traditional hospital waste incinerators, the incinerator may be operated continuously. Controlled-air incinerators are normally operated in batch mode. 

All factors suggest that a rotary kiln incineration unit would be more appropriate for this facility than a controlled-air incineration system. 

In the past, controlled-air incinerators have been the most popular incinerators for biomedical waste destruction. A controlled-air incinerator is a two-chamber, hearth-burning, pyrolytic unit. The primary chamber receives the waste and bums it with less than stoichiometric air. Volatiles released in the primary chamber are burned in the secondary combustion chamber. These units result in low fly ash generation and low particulate emissions. In addition, they have a low capital cost and may be batch operated. They normally do not require air pollution control equipment unless acid gas emissions are excessive. 

Not currently active In the salfe of this line of equipment. Controlled air incinerator with secondary combustion chamber... 

Hofmann, R. E., Controlled-Air Incineration--Key to Practical Production of Energy from Wastes, Public Works, 107(9) 72-79, 136, 138 (September 1976). 

Kleinhenz, N., and H, G. Rigo, "Operational Testing of a Controlled Air Incinerator with Automatic Ash Handling, report prepared by Systems Technology Corp. for the Navy Civil Engineering Laboratory, Port Hueneme, CA (November 1976). 

Before the early 1960 s, institutional incineration systems were almost exclusively multiple-chamber types, designed and constructed according to Incinerator Institute of America (IIA) Incinerator Standards. Since these systems operated with high excess air levels, most required scrubbers in order to comply with air pollution control standards. Multiple-chamber type systems are occasionally installed at modem facilities because they represent proven technology. However, the most widely and extensively used incineration technology over the past 20 years is controlled-air incineration. This has also been called starved-air incineration, two-stage incineration, modulaf combustion, and pyrolytic combustion. More than 7000 controlled-air type systems have been installed by approximately 2 dozen manufacturers over the past 2 decades. 

The first controlled air incinerators were installed in the late 1950s, and the first U.S. controlled-air incinerator company was formed in 1964. The controlled-air incineration industry grew very slowly at first. The technology received little recognition because it was considered unproven and radically different from the estabhshed and widely accepted IIA Incinerator... 

Today there are approximately a dozen hsted manufacturers of controlled air incinerators. However, oiily about half of these have established successful track records with demonstrated capabihties and qualifications for providing first-quality installations. In fact, some of the manufacturers listed in the catalog have yet to install their first system, and a few are no more than brokers who buy and install incinerator equipment manufactured by other firms. 

A typical daily operating cycle for a controlled air incinerator without automatic ash removal is as follows ... 

Early attempts at automatic ash removal in controlled air incinerators employed a bomb bay door concept. With these systems, the bottom of the primary chamber would swing open to drop ashes into a container or vehicle located below. Serious operating problems led to the discontinuance of these systems. More recent automatic ash removal systems use rams or plungers to push a mass of residue through the primary chamber and out a discharge door on a batch basis. Most of these systems have had only limited success. 

McRee, RE, Controlled-air incinerators for hazardous waste application theory and practice, Proc, APCD Int. Workshop Ser. on Hazardous Waste, New York, April 1, 1985. 

The solid wasfe processing systems include the radwaste volume reduction/snlidifiratinn system and the radwaste incinerator. The systems reduce in volume and solidify low-level radioactive planf wasfes to prepare them for safe storage and/or disposal. The radwaste volume reduction/solidification system employs a vacuum-cooled crystallization process to effect volume reduction, coupled with high speed, higher shear mixing of the waste with cement to achieve solidification. For combustible plant wastes, the radwaste incinerator utilizes a controlled air incineration process. 

The thermal processes are essentially incineration and melting. The types of incinerators in use include excess air incinerators, controlled air incinerators, fluidised bed incinerators, etc. The available melting processes include conventional melters, electroslag melters, plasma melters, etc. 

Controlled-air incinerators (Fig. 4.79), the most frequently used incinerators today, were first commercially available in the United States in the early 1960s, bnt they were not really... 

FIGURE 4.79 Controlled-air incinerator. Adapted with permission from the American City County Magazine.)... 

The controlled air incinerators limit the air supply in the primary combustion step (e.g. to near or below the stoichiometric ratio), and a secondary combustion step is needed for the completion of the combustion of the gaseous fraction in an oxygen rich atmosphere. 

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