Abstract: An apparatus for measuring the combustion effluent of a fossil-fired system with high accuracy as required for the determination of fuel flow rate and boiler efficiency.

Abstract: A heat exchange module comprises a rotating-wheel type regenerative heat exchanger unit having a plurality of heat exchange elements mounted in baskets through the volume of the heat exchanger wheel. The heat exchanger wheel rotates about its axis so that the heat exchange elements are heated by a hot gas flow over a portion of the rotation, and transfer the heat to an air flow over another portion of the rotation. At least some of the heat exchange elements include phase change materials, such as salts, that absorb heat while maintaining a constant temperature. The phase change materials narrow the range of temperatures reached by the heat exchange elements located at various positions of the heat exchanger wheel. The phase change materials prevent excessively low temperatures that can result in condensation of corrosive acids on the surfaces of the heat exchange elements.

Abstract: A sulfur trioxide conditioning system includes a catalytic converter that converts a portion of the sulfur dioxide in a flow of flue gas to sulfur trioxide. The catalytic converter includes a catalyst support, which is disposed across at least a portion of the cross section of a main duct from a burner to a heat recovery apparatus, and a catalyst on the catalyst support. The amount of the catalyzed surface exposed to the flow of flue gas is selectively varied to control the conversion of sulfur dioxide to sulfur trioxide.

Abstract: A hot-side electrostatic precipitator removes particulate matter from a NOX-containing flue gas stream passing therethrough, the exit flue gas stream having a temperature of no less than about 450F. The precipitator contains a plurality of collecting surfaces arranged in a series of fields. At least some of the collecting surfaces carry a catalyst which promotes a reaction between NOX in the flue gas passing therethrough and a nitrogeneous compound. Preferably, a nitrogeneous compound such as ammonia is electrically charged and injected into the flue gas stream prior to its passing over the collecting surfaces coated with catalyst. The hot-side electrostatic precipitator may have catalyst coated onto fixed surfaces near its exit end.

Abstract: An apparatus for reducing NOx pollution in the flue gas produced by a burner includes a heat exchanger wherein at least some of the heat transfer elements are coated with a catalyst. A plurality of reactive gas injectors are arranged to introduce a nitrogeneous compound, preferably a source of ammonia, across a hot-end face of the heat exchanger. A reactive gas flow distribution system permits the distribution of the nitrogeneous compound flowing through at least some of the gas injectors to be varied responsive to the temperature profile of the heat exchanger. Preferably, the apparatus also determines the total NOx flow in the flue gas, and the reactive gas flow distribution system permits the total amount of reactive gas flowing through at least some of the gas injectors to be varied responsive to the total NOx flow in the flue gas.

Abstract: The NOx content in a flow of flue gas is reduced by passing the flue gas through a first treatment zone and a second treatment zone. A nitrogeneous treatment agent is introduced into the first treatment zone for the selective non-catalytic reduction of part of the NOx, and the flue gas is thereafter passed through the second treatment zone which includes a catalyst for further selective catalytic reduction of the NOx. Optionally, a second nitrogeneous treatment agent is added to the flue gas in the second treatment zone. The quantity of NOx in the flue gas is detected intermediate the first and second treatment zones and, optionally, after the flue gas has left the second treatment zone. The quantity of ammonia in the flue gas exiting from the second treatment zone is also detected. The amounts of the treatment agents added to the flue gas are controlled responsive to the variations and absolute levels determined by these measurements.