Thermal Destruction and Carbonaceous Particulate Formation During the Pyrolysis and Combustion of Chlorinated Hydrocarbons

本研究的总体目标是描述在不同空气/燃料比和不同周围热化学环境下，氯化烃（CHC）燃料热解和燃烧过程中的热破坏和产物形成机制（主要产物种类以及二恶英和呋喃）。还将确定各种CHC燃料在热解和燃烧过程中形成的烟灰和碳质颗粒以及在一定温度范围内的点火延迟时间。选择具有工业危险废物代表性的CHC燃料液滴/颗粒，并测定其沿控温-组成反应器轴向通过时的时间分解行为。因此，将获得关于这些燃料在燃料颗粒/液滴大小、颗粒间间距以及颗粒周围的热和化学环境等明确规定的条件下的热破坏、汽化和燃烧的信息，以便指导制定有效热破坏危险废物的策略，并确定点火延迟。燃烧速率、破坏效率和挥发性有机化合物、二恶英、呋喃、烟灰和燃烧过程中的碳质颗粒的形成。这种方法将获得关于CHC燃料热破坏和产物形成的速率和机理信息。将特别强调确定在这些燃料燃烧过程中避免氯、光气、烟灰、微粒、二恶英和呋喃形成的方法。进行这项研究的动机是需要有关氯化烃化合物燃烧和污染特性的科学和工程资料，以便能够以环境可接受的方式设计和更可靠和令人满意地运行大型危险化学废物焚烧系统，而不会对人类健康和环境造成不当危害环境。由于我们目前对CHCs的燃烧特性缺乏了解，特别是在热破坏和各种有毒产物的产生方面，导致焚化炉的设计采用高度经验的方法。该研究项目旨在更好地了解热破坏和产物形成机制，以及确定在危险氯化废物焚烧过程中与这些物种相关的烟灰和颗粒形成和点火延迟时间的信息。

The overall objective of this investigation is delineation of mechanisms of thermal destruction and product formation (major product species as well as dioxins and furans) during the pyrolysis and combustion of chlorinated hydrocarbon (CHC) fuels at different air/fuel ratios and various surrounding thermal and chemical environments. Soot and carbonaceous particles formed during pyrolysis and combustion of various CHC fuels as well as ignition delay times over a range of temperatures will also be determined. Droplets/particles of CHC fuels representative of industrial hazardous wastes will be selected and their time-resolved behavior during passage along the axis of controlled temperature-composition reactor determined. Information will thus be obtained on the thermal destruction, vaporization, and combustion of these fuels under well-defined conditions of fuel particle/droplet size, inter- particle spacing, and thermal and chemical envirionment around the particle in order to guide the development of strategies for effective thermal destruction of hazardous wastes in addition to determining ignition delays, combustion rates, destruction efficiencies, and formation of volatile organic compounds, dioxins, furans, soot, and carbonaceous particles during combustion. This approach will yield rate and mechanistic information on the thermal destruction and and product formation of CHC fuels. Particular emphasis will be place on definition of approaches for avoidance of formation of chlorine, phosgene, soot, particulates, dioxins, and furans during the combustion of such fuels. The incentive for this research arises from the need for scientific and engineering information on the combustion and pollution characteristics of chlorinated hydrocarbon compounds such that large-scale hazardous chemical waste incineration systems can be designed and operated more reliably and satifactorily in an environmentally acceptable manner without undue hazard to human health and environment. The lack of our present understanding on the combustion characteristics of CHCs, particularly as regards thermal destruction and production of various toxic products, has resulted in the use of highly empirical methods for design of incinerators. This research program is aimed at development of a better understanding of the thermal destruction and product formation mechanisms, as well as determination of information regarding formation of soot and particulates and ignition delay times associated with these species during the incineration of hazardous chlorinated wastes.