Acid coal pile drainage prevention

Sandra L Mansilla-Soto, Purdue University

Abstract

The purpose of the present study was to evaluate different compounds or mixtures to prevent acid coal pile drainage. Acid coal pile drainage refers to the low pH drainage from the water leached through the high sulfur coal piles. Purdue University owns and operates a co-generating power plant that produces steam and electricity from the combustion of coal, gas, and oil. In the summer of 1995, Purdue's Power Plant supported a research project that concluded that high sulfur coal is detrimental to the environment. Drainage from high sulfur coal storage areas usually has an extremely low pH (pH 2-3) and generally contains high concentrations of metallic ions (Al, Fe, Hg, Ni, Zn, etc.), sulfates, and suspended solids. The present research was divided in a flask scale (Phase 1) and in a pilot scale (Phase 11) to screen for possible inhibitory compounds or mixtures to minimize or prevent acid coal pile drainage. In the flask experiments: two organic compounds, nine organic acids, six nitrification inhibitory compounds, three surfactants, five antibacterial/antibiotics, five polymers, and four binary mixtures of surfactants with antibacterial/antibiotics were screened. The compounds or mixtures evaluated at pilot scale were based on the optimum results from flask experiments. Effectiveness of the compounds or mixtures was measured against a control (high sulfur coal) in terms of pH, acidity or alkalinity and ferrous iron concentration. From all the compounds analyzed, the binary mixture of dodecylamine at 0.0938M with tetracaine at 375ug/L and polymer C-31 at 0.75% (w/v) in solution sprayed over high sulfur coal were the best at minimizing acid coal drainage compared to the control samples. ^

Degree

Ph.D.

Advisors

Major Professor: Ronald F. Wukasch, Purdue University.

Subject Area

Environmental Sciences|Engineering, Environmental

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