Abstract: Clay and slag additions are made during coal combustion processes to reduce unwanted emissions such as SO2, NOx and mercury. The clay additives may include kaolin. The slag additives may include stainless steel slag. The resultant combustion products may be used as cement additives.

Abstract: Coal is combusted in the presence of a clay additive and a slag additive to produce a combustion product that is useful as a pozzolanic additive for cement. The combustion process may be performed in a coal-fired boiler of an electrical power generation plant, resulting in improved operational efficiency and controlled emissions.

Abstract: Coal is combusted in the presence of a clay additive and a slag additive to produce a combustion product that is useful as a pozzolanic additive for cement. The combustion process may be performed in a coal-fired boiler of an electrical power generation plant, resulting in improved operational efficiency and controlled emissions.

Abstract: A method and system for producing modified coal combustion products are disclosed. The additives reduce the particle sizes of the coal combustion product and may reduce the amount of un-burned carbon in the coal combustion product, making the modified product useful as an addition to cementitious materials.

Abstract: The present invention provides combustion products of hydrocarbon fuels and controlled amounts of metal oxide strength enhancing materials. The combustion products are useful as additives to cementitious materials. A hydrocarbon fuel such as coal is introduced into a combustion chamber and selected amounts of materials comprising CaO, SiO2 and Al2O3 are also introduced into and/or downstream from the chamber. The hydrocarbon fuel undergoes combustion while the metal oxide strength enhancing materials react with each other and/or the ash or other reaction products of the hydrocarbon fuel. The combustion products have been found to significantly increase compressive strengths of cements such as Portland cement. A reduction in SO2 emission levels also results from the introduction of the metal oxide strength enhancing materials into the combustion process.

Abstract: The present invention provides combustion products of hydrocarbon fuels and controlled amounts of metal oxide strength enhancing materials. The combustion products are useful as additives to cementitious materials. A hydrocarbon fuel such as coal is introduced into a combustion chamber and selected amounts of materials comprising CaO, SiO2 and Al2O3 are also introduced into and/or downstream from the chamber. The hydrocarbon fuel undergoes combustion while the metal oxide strength enhancing materials react with each other and/or the ash or other reaction products of the hydrocarbon fuel. The combustion products have been found to significantly increase compressive strengths of cements such as Portland cement. A reduction in SO2 emission levels also results from the introduction of the metal oxide strength enhancing materials into the combustion process.

Abstract: A fan venturi blockage detector for a DC electric fan and an associated method are disclosed employing a current detector for measuring the input current to the DC electric fan, and a processor connected to the current detector. The processor stores the measured input current value for the minimum input current to the fan under normal operating conditions, and sets a minimum current threshold at a value less than the normal operating condition measured current. The processor compares subsequent measured input current values with the minimum current threshold value, and provides an error signal upon the subsequent measured input current having a value equal to or less than the minimum current threshold value.