Evaluation of high-temperature disposable filter elements in an experimental underground mine

Transactions of the Society for Mining, Metallurgy, and Exploration , 2011, Vol. 330, No. 1, pp. 373-382

Bugarski, A.D.; Schnakenberg, G.H.; Hummer, J.A.; Cauda, E.G.; Janisko, S.J.; Patts, L.D.

 Filtration systems with disposable filter elements (DFEs) are used in the underground coal mining industry to control particulate matter emissions from diesel-powered permissible and nonpermissible coal mining equipment. This study was conducted in underground mine conditions to evaluate three types of high-temperature DFEs used in those filtration systems. The DFEs were evaluated for their effects on the concentrations and size distributions of diesel aerosols and concentrations of nitric oxide (NO) and nitrogen dioxide (NO₂). Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. After an initial DFE degreening period, the filtration system with all three DFEs was found to be very effective at reducing total mass concentrations of aerosols in the mine air. The effectiveness of DFEs in filtering aerosol mass was found to be a function of the engine operating conditions. The efficiency of the new DFEs significantly increased with operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on the performance of the DFE elements. The effectiveness of DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for DFEs when the engine was operated at high-load modes rather than at low-load modes. Initial heating of certain DFEs resulted in visible white smoke and substantially elevated aerosol number concentrations. The effects of the DFEs on the total concentration of nitrogen oxides (NO_X) were found to be minor. The NO₂ fraction was found to be generally lower for the DFEs than for the muffler. The engine-out NO₂ fraction of the total NO_X was found to be substantially higher for low-load modes than for high-load modes..