An accurate thermodynamic model of an Active Lean NOx (ALNC) Catalyst is presented. The model takes into account hydrocarbon storage and release mechanisms of the ALNC, as well as the degradation in the ALNC hydrocarbon conversion efficiency due to ageing, and thus provides a more accurate estimate of an exotherm generated by hydrocarbon combustion in the ALNC. The estimated exotherm can them be used to detect system degradation and identify components responsible for the degradation.

Diesel aftertreatment systems

Dual fuel injection nozzle with water injection

The present invention provides for the retrofitting diesel truck engines with a system to reduce NOx emissions. The SCR system of the present invention, including a controller, a reagent tank, and an injection system, is installed on a vehicle. A NOx detector is temporarily installed as part of the system. The vehicle is then operated to collect engine parameters including fuel injection timing, RPM, load, exhaust heat, exhaust flow rate, and the like, together with measurements of the NOx emissions under various operating conditions. Based on the recorded data at various operating conditions, a reagent injection strategy is developed and installed at the reagent injection controller. During vehicle operation, the injector injects reagent into the exhaust system based on control signals from the reagent injection controller in accordance with the injection strategy in order to reduce NOx emissions at the various operating conditions.

Mobile diesel selective catalytic reduction systems and methods

An integrated power plant comprises a gas-turbine set with a compressor, a combustion chamber and a gas turbine, a heat-recover boiler arranged downstream of the gas turbine, and a water/steam circuit with a steam turbine, a condenser, a feedwater tank and a separately fired steam generator having a flue-gas NOx-reduction unit arranged on the flue-gas side downstream of the steam generator, the heat-recovery boiler for the generation of steam being incorporated in the water/steam circuit In such a power plant, in order to improve the part-load behavior, a branch line is provided at the heat-recovery boiler, by means of which branch line a predetermined portion of the exhaust gases coming from the gas-turbine set and flowing through the heat-recovery boiler can be branched off and added upstream of the flue-gas NOx-reduction unit to the flue gases coming from the steam generator

Integrated power plant and method of operating such an integrated power plant

An engine exhaust aftertreatment system is described in which lean NO x , exhaust aftertreatment devices are employed. Because temperature in the exhaust line varies as a function of distance from the engine and engine operating condition, exhaust aftertreatment devices are situated along the exhaust line to ensure that at least one of said exhaust aftertreatment devices operates at a temperature of high NO x conversion efficiency. Reductant quantity is scheduled by the engine's control unit to be supplied to the exhaust aftertreatment devices based on available information provided by sensors or embedded engine control unit models, including: temperature in the exhaust aftertreatment devices, available reductant in the exhaust stream, reductant storage in the exhaust aftertreatment devices, maximum adsorption capacity of the exhaust aftertreatment devices, engine operating conditions, and NO x , concentration.

Emission control system

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.

Control of nox reduction in flue gas flows

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. They can also stabilize the heat exchange elements in particularly desirable temperature ranges for the operation of catalysts coated onto the heat exchange elements.

Wayne R Kozacka

Papers

Control of nox reduction in flue gas flows

Temperature-stabilized heat exchanger