This paper reports on the observed behavior of coal particles during thermal decomposition. The data presented are the first from a study initiated to address both the physical and chemical behavior of pulverized coal from the time of initial heating through the evolution of soot particulate. In the present study, pulverized (high volatile bituminous) coal was injected through a slit centered in a methaneair flat flame burner, and high resolution holography was employed to record the evolution of volatiles and the structure of soot particulate. Volatiles were observed to evolve in a variety of shapes that range from individual jets to uniformly distributed clouds. Coal particle fragments and/or incipient soot nodules (∼ 3 micron) were found to be present within the volatile gases during the evolution. Further from the burner, stringlike soot particles approaching 1600 microns in length were observed. © 1981.

Incineration is a promising technique for the disposal of organic hazardous wastes. However, the waste destruction characteristics of turbulent spray flames have not been characterized. In the present research two reactors are used to simulate various aspects of liquid injection incinerator flame zones. The following questions are addressed: (1) Under what conditions do flames quantitatively destroy waste compounds, and (2) how must the flame be perturbed to cause it to fail to quantitatively destroy wastes. The two reactors operated on a simulated waste stream consisting of acrylonitrile, benzene, chlorobenzene, and chloroform. A microspray reactor was used to investigate destruction processes associated with individual droplets of waste compounds. A turbulent flame reactor used a heptane-fueled waste-doped turbulent spray flame to simulate incinerator flame-zone processes. The flames were found to be capable of quantitative waste destruction without the necessity of using common post-flame processes such as afterburners. Furthermore, the high waste destruction efficiency conditions corresponded to high combustion efficiency conditions (i.e., minimum CO and hydrocarbon emissions). Failure to achieve high destruction efficiency resulted from the perturbation of flame parameters. Failure conditions were identified with high and low theoretical air, low temperature, poor atomization quality, and flame impingement on a cold surface. Each failure condition also resulted in elevated CO and hydrocarbon emissions. Thus, the results suggest that CO and hydrocarbon measurements can be used as an indirect, continuous means of monitoring incinerator flame-zone performance. © 1985 Combustion Institute.