Abstract: Cementitious mixtures comprising precipitate calcium carbonate (PCC) and hydraulic cement and methods of making same. The PCC may be obtained as a precipitate product from reaction of flue gas desulverization wastewater (FGDW) and sodium carbonate.

Abstract: An initial coal is cleaned to reduce ash content by ?20% and yield refined coal that optimizes combustion air flow through a coal burner. This permits conveyance of pulverized refined coal in suspended condition through feeder pipes of the coal burner using reduced air flow compared to the quantity of air required to convey pulverized initial coal in suspended condition through the feeder pipes. This reduces oxygen in the primary combustion zone, lowering conversion of fuel nitrogen into NOx and instead converting it into N2 using the refined coal product. Reduced primary combustion air also reduces core flame temperature, reducing thermal NOx formation using the refined coal product. Increasing secondary and/or tertiary combustion air compensates for reduced primary combustion air and result in overall decrease in NOx formation (e.g., thermal NOx formation is reduced when combustion completed in cooler secondary and/or tertiary combustion zones).

Abstract: An initial coal is cleaned to reduce ash content by ?20% and yield refined coal that optimizes combustion air flow through a coal burner. This permits conveyance of pulverized refined coal in suspended condition through feeder pipes of the coal burner using reduced air flow compared to the quantity of air required to convey pulverized initial coal in suspended condition through the feeder pipes. This reduces oxygen in the primary combustion zone, lowering conversion of fuel nitrogen into NOx and instead converting it into N2 using the refined coal product. Reduced primary combustion air also reduces core flame temperature, reducing thermal NOx formation using the refined coal product. Increasing secondary and/or tertiary combustion air compensates for reduced primary combustion air and result in overall decrease in NOx formation (e.g., thermal NOx formation is reduced when combustion completed in cooler secondary and/or tertiary combustion zones).

Abstract: Methods, processes, and systems for reducing the solubility of toxic constituents found in coal combustion residues are provided. In one embodiment, methods for adding chemical reagents to the coal combustion process that changes the chemical composition of the coal combustion residues and convert the form of a toxic constituents to one with lower aqueous solubility is provided. In some embodiments compounds containing toxic constituents are converted to compounds that are less soluble in aqueous solvents. In various embodiments, the chemical reactions are aided by the ambient heat at various zones within the coal combustion system. In some embodiments, precursor reagents are added to the coal combustion system and converted to reagents to aid in interacting with toxic constituents or compounds. In various embodiments, the reagent or reagent precursor is added before, during, or after the coal combustion zone.

Abstract: An initial coal feedstock comprised of primary or second coal is cleaned so as to reduce its ash content by at least about 20% in order to yield a refined coal product that produces fewer NOx emissions. The reduced NOx emissions result primarily from the ability to use less primary combustion air in order to maintain the pulverized refined coal in a suspended condition within the feeder pipes of a coal burner compared to the minimum quantity of air required to maintain pulverized coal from the initial coal feedstock in a suspended condition within the feeder pipes. Reducing the primary combustion air reduces the amount of oxygen in the primary combustion zone that would otherwise be available for converting fuel nitrogen into NOx. Instead, more of the fuel nitrogen is converted into N2. Reducing the primary combustion air also reduces the temperature of the core flame, reducing thermal NOx formation.

Abstract: A process is described that removes by chemical oxidation the excess ammonia (NH3) gas from flue gases that have been subjected to selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) of oxides of nitrogen (NOx) by ammonia injection. Methods for the removal of residual ammonia from flue gases prior to fouling air pre-heaters or deposition on fly ash are discussed.

Abstract: A method and system for treating fly ash by addition of a chemical reagent during fly ash transfer operations. The method includes discharging fly ash from a fly ash storage silo and metering the mass flow rate of the fly ash being discharged with a mass flow metering device. The method also includes generating a signal from the mass flow metering device corresponding to the mass flow rate of the fly ash and adding a chemical reagent to the fly ash at a selected chemical reagent addition rate with a chemical feeding device, wherein the chemical reagent addition rate is selected based upon the mass flow rate of fly ash removal. The method also includes blending the chemical reagent with the fly ash to treat the fly ash and transferring the treated fly ash to a work or disposal location.