Abstract: A method of reducing selenium contamination in a waste water stream is described herein. The method includes channeling a flue gas stream through an absorber, contacting the flue gas stream with an aqueous alkaline-based slurry, such that any selenium byproduct in the flue gas stream forms a selenium compound within the aqueous alkaline-based slurry, controlling oxidation of the selenium compound in the aqueous alkaline-based slurry, and adding a precipitation agent to the aqueous alkaline-based slurry to cause the selenium compound within the aqueous alkaline-based slurry to precipitate.

Abstract: A system and method of using the system for controlling oxidation of sulfites to reduce total nitrite and nitrate levels in a slurry is disclosed. The system includes a tank having an inlet for receiving a slurry produced in a wet flue gas desulfurization process. The tank also includes an inlet for receiving a gas. The inlet for receiving the gas is operable to disperse at least a portion of the gas received in the tank through at least a portion of the slurry received in the tank. A sensor is configured to measure a sulfite concentration of the slurry received in the tank to obtain a sulfite concentration measurement. In some embodiments, the sensor is a sulfite analyzer. In other embodiments, the sensor is a virtual analyzer. The system also includes a controller. Software executing on the controller generates an electronic signal affecting an adjustment of a flow rate of gas into the slurry in the tank based at least in part on the sulfite concentration/sulfite concentration measurement.

Abstract: A method of reducing selenium contamination in a waste water stream is described herein. The method includes channeling a flue gas stream through an absorber, contacting the flue gas stream with an aqueous alkaline-based slurry, such that any selenium byproduct in the flue gas stream forms a selenium compound within the aqueous alkaline-based slurry, controlling oxidation of the selenium compound in the aqueous alkaline-based slurry, and adding a precipitation agent to the aqueous alkaline-based slurry to cause the selenium compound within the aqueous alkaline-based slurry to precipitate.

Abstract: Systems and methods are described for treating flue gas, for example from a coal fired power plant. The systems and methods include control of a wet flue gas desulfurization (WFGD) system to manage sulfite concentration in a slurry produced by the WFGD system. Oxygen is added to the slurry in an amount sufficient to produce a sulfite concentration in the slurry in the range of about 5 to 75 mg/L, an oxidation reduction potential in the range of about 100-250 mV, or both. The systems and methods also include the biological treatment to remove selenium from a liquid fraction of the slurry. The liquid fraction is treated in a biological reactor maintained under anoxic or anaerobic conditions to reduce its selenium concentration.

Abstract: A system and method of using the system for controlling oxidation of sulfites to reduce total nitrite and nitrate levels in a slurry is disclosed. The system includes a tank having an inlet for receiving a slurry produced in a wet flue gas desulfurization process. The tank also includes an inlet for receiving a gas. The inlet for receiving the gas is operable to disperse at least a portion of the gas received in the tank through at least a portion of the slurry received in the tank. A sensor is configured to measure a sulfite concentration of the slurry received in the tank to obtain a sulfite concentration measurement. In some embodiments, the sensor is a sulfite analyzer. In other embodiments, the sensor is a virtual analyzer. The system also includes a controller. Software executing on the controller generates an electronic signal affecting an adjustment of a flow rate of gas into the slurry in the tank based at least in part on the sulfite concentration/sulfite concentration measurement.

Abstract: An apparatus for evaporating waste water and reducing gas emissions includes an evaporator device configured to receiving a portion of flue gas emitted from a boiler unit and waste water to directly contact the flue gas with the waste water to cool and humidify the flue gas and to dry solid particulates within the waste water. In some embodiments, the waste water may be a component of a mixture formed by a mixer device prior to being contacted with the flue gas to humidify and cool the flue gas and dry solids within the waste water. An alkaline reagent as well as activated carbon can be mixed with the waste water prior to the waste water contacting the flue gas. Solid particulates that are dried within the cooled and humidified flue gas can be separated from the flue gas via a particulate collector.

Abstract: The present application provides a waste water preconditioning system for limiting mercury concentrations in a waste water stream resulting from treatment of a flue gas. The waste water preconditioning system may include a wet flue gas desulfurization system for treating the flue gas with an aqueous alkaline slurry, a sulfite detector to determine the concentration of sulfite in the aqueous alkaline slurry, and to produce the waste water stream with a mercury concentration of less than about five micrograms per liter. The waste water preconditioning system also may include a waste water treatment system downstream of the wet flue gas desulfurization system.

Abstract: An apparatus for evaporating waste water and reducing flue gas acid gas emissions includes an evaporator device configured to receive a portion of flue gas emitted from a combustion unit and waste water for direct contact of the flue gas with the waste water to cool and humidify the flue gas, and to evaporate the waste water. An alkaline reagent as well as activated carbon may be mixed with the waste water prior to waste water contact with the flue gas. Solid particulates that are dried and entrained within the cooled and humidified flue gas can be separated from the flue gas via a particulate collector.

Abstract: A method and a system (12) for reducing plant (10) gas emissions by reducing ammonia/ammonium ion content in waste water W prior to the waste water W being evaporated in an evaporator device (7). As such, the method and the system (12) reduce the release of ammonia/ammonium ion into the flue gas FG stream thus reducing emissions of ammonia/ammonium ions to the environment or atmosphere and/or accumulation of ammonia/ammonium ions in downstream equipment such as a wet flue gas desulfurization system (13).

Abstract: An method of operating a plant includes the steps of feeding a reagent to a direct contact heating device (32) for removing ammonia from fluid fed to the direct contact heating device (32), feeding water to the direct contact heating device (32) to contact the fluid after the fluid is contacted with the reagent fed to the direct contract heating device (32), and feeding the water from the direct contact heating device (32) to a water wash tower (20) that is downstream of a carbon dioxide absorber (14) configured to use ammonia to remove carbon dioxide from fluid fed therein. The water wash tower (20) can be configured to remove ammonia from the fluid fed therein prior to that fluid being fed to the direct contact heating device (32). A plant and an apparatus for integrating desulfurization and carbon capture are configurable to implement the method.

Abstract: An apparatus for evaporating waste water and reducing gas emissions includes an evaporator device configured to receiving a portion of flue gas emitted from a boiler unit and waste water to directly contact the flue gas with the waste water to cool and humidify the flue gas and to dry solid particulates within the waste water. In some embodiments, the waste water may be a component of a mixture formed by a mixer device prior to being contacted with the flue gas to humidify and cool the flue gas and dry solids within the waste water. An alkaline reagent as well as activated carbon can be mixed with the waste water prior to the waste water contacting the flue gas. Solid particulates that are dried within the cooled and humidified flue gas can be separated from the flue gas via a particulate collector.

Abstract: An apparatus for evaporating waste water and reducing flue gas acid gas emissions includes an evaporator device configured to receive a portion of flue gas emitted from a combustion unit and waste water for direct contact of the flue gas with the waste water to cool and humidify the flue gas, and to evaporate the waste water. An alkaline reagent as well as activated carbon may be mixed with the waste water prior to waste water contact with the flue gas. Solid particulates that are dried and entrained within the cooled and humidified flue gas can be separated from the flue gas via a particulate collector.

Abstract: A method and a system (12) for reducing plant (10) gas emissions by reducing ammonia/ammonium ion content in waste water W prior to the waste water W being evaporated in an evaporator device (7). As such, the method and the system (12) reduce the release of ammonia/ammonium ion into the flue gas FG stream thus reducing emissions of ammonia/ammonium ions to the environment or atmosphere and/or accumulation of ammonia/ammonium ions in downstream equipment such as a wet flue gas desulfurization system (13).

Abstract: A system and method for controlling oxidation of sulfites in a slurry. The system includes a tank having an inlet for receiving a slurry used in wet flue gas desulfurization. The tank also includes an inlet for receiving a gas. The inlet for receiving the gas is configured so that at least a portion of the gas received in the tank is dispersed through at least a portion of the slurry received in the tank. A sensor is configured to measure a sulfite concentration S1 of the slurry received in the tank. In some embodiments, the sensor is a sulfite analyzer. In other embodiments, the sensor is a virtual analyzer. The system includes a controller. Software executing on the controller generates a signal indicative of an adjustment of a flow rate of gas into the tank based at least in part on the sulfite concentration S1.

Abstract: A system and method for controlling oxidation of sulfites in a slurry. The system includes a tank having an inlet for receiving a slurry used in wet flue gas desulfurization. The tank also includes an inlet for receiving a gas. The inlet for receiving the gas is configured so that at least a portion of the gas received in the tank is dispersed through at least a portion of the slurry received in the tank. A sensor is configured to measure a sulfite concentration S1 of the slurry received in the tank. In some embodiments, the sensor is a sulfite analyzer. In other embodiments, the sensor is a virtual analyzer. The system includes a controller. Software executing on the controller generates a signal indicative of an adjustment of a flow rate of gas into the tank based at least in part on the sulfite concentration S1.

Abstract: An method of operating a plant includes the steps of feeding a reagent to a direct contact heating device (32) for removing ammonia from fluid fed to the direct contact heating device (32), feeding water to the direct contact heating device (32) to contact the fluid after the fluid is contacted with the reagent fed to the direct contract heating device (32), and feeding the water from the direct contact heating device (32) to a water wash tower (20) that is downstream of a carbon dioxide absorber (14) configured to use ammonia to remove carbon dioxide from fluid fed therein. The water wash tower (20) can be configured to remove ammonia from the fluid fed therein prior to that fluid being fed to the direct contact heating device (32). A plant and an apparatus for integrating desulfurization and carbon capture are configurable to implement the method.

Abstract: A wet flue gas desulfurization (WFGD) system includes an absorber vessel operable to remove pollutants from flue gas supplied thereto. The absorber vessel defines a slurry section for containing a reagent slurry therein and an outlet in fluid communication with the slurry section. The WFGD system includes a mercury removal vessel in fluid communication with outlet. The mercury removal vessel has activated carbon disposed therein.

Abstract: A gas-liquid contactor for removing gases and particulate matter from flue gases produced by processing operations of the type carried out in utility and industrial plants. The contactor is generally an open spray absorber having a spray tower (110) whose walls (114) form a passage within the tower (110). Flue gases are introduced into the tower (110) so as to flow vertically upward or downward through the passage. Disposed within the passage are heads (116) for introducing a liquid (118) into the passage such that the liquid (118) contacts the flue gases. A portion of the liquid (118) contacts the wall (114) of the tower (110), such that the portion of the liquid (118) flows downwardly along the wall (114). The tower (110) is equipped with a deflecting device (122) disposed on the wall (114) for deflecting the portion of the liquid (118) away from the wall (114), and thereafter reintroducing the portion of the liquid (118) into the passage so as to contact the gases flowing through the passage.