Energy & Fuels, Vol.30, No.12, 10886-10892, 2016
Ignition of the Coal-Water Slurry Containing Petrochemicals and Charcoal
The lack of effective technologies to use coal processing waste and waste flammable liquids is a major research and development problem. To address this problem, we study the ignition characteristics and conditions for coal water slurries (CWS) based on these wastes. The key challenge posed by the wastes under study is their poor reactivity (they require more power resources for sustainable ignition). Therefore, this paper suggests adding a highly reactive material (charcoal) in a low concentration to coal water-slurry containing petrochemicals (CWSP) based on wastes. Individual CWSP droplets are studied in a model combustion chamber. The integral characteristics of the processes under study (ignition delay time and minimum oxidizer temperatures sufficient for ignition) are determined for a CWSP droplet of 0.5-2 mm in radius fixed at the junction of a low-inertia thermocouple using a high-speed (up to 10(5) fps) video camera and Tema Automotive software. We compare the ignition characteristics of CWSP compositions based on charcoal and brown coal as well as filter cakes (processing waste) of coking, low-caking, and non-baking coals in an oxidizer flow (temperature of 600-1000 K and velocity of 0.5-5 m/s). Charcoal is a promising additional component for the CWS and CWSP. In view of ecological, economic, and energy-related aspects, it is advisible to use charcoal as an additive to intensify the CWS and CWSP ignition. Even a small addition (within 10-15% in relative mass concentration) of this component may significantly reduce the limit (minimum) temperature of sustainable ignition and ignition delay time (inertia).