Abstract: A method of removing mercury from a process gas by means of a sorbent and a filter (10) involves applying said sorbent to at least one filtering surface (12) of the filter (10). A first parameter, which is indicative of the amount of mercury that needs to be removed in said filter (10), and a second parameter, which is indicative of the amount of material that has been collected on said filtering surface (12), are measured. A measured value of said first parameter is compared to a mercury set point. When said measured value of said first parameter is higher than said mercury set point, the cleaning of said filtering surface (12) is delayed, compared to the point in time suggested by a measured value of said second parameter.

Abstract: The subject matter disclosed herein relates to a method of reducing an amount of mercury discharged to an environment in a flue gas (12) generated by combustion of a fuel source. The method includes contacting the flue gas with a moist pulverous material upstream of a particle separator (24), mixing powdered activated carbon (PAC) in an amount between about 0.5 lb/MMacf and 10 lbs/MMacf with the flue gas (12) upstream of the particle separator (24), wherein the PAC interacts with at least a portion of mercury containing compounds in the flue gas (12), and separating the mercury containing compounds from the flue gas (12) containing the moist pulverous material and PAC, thereby reducing an amount of mercury in the flue gas (12).

Abstract: A method of removing mercury from a process gas by means of a sorbent and a filter (10) involves applying said sorbent to at least one filtering surface (12) of the filter (10). A first parameter, which is indicative of the amount of mercury that needs to be removed in said filter (10), and a second parameter, which is indicative of the amount of material that has been collected on said filtering surface (12), are measured. A measured value of said first parameter is compared to a mercury set point. When said measured value of said first parameter is higher than said mercury set point, the cleaning of said filtering surface (12) is delayed, compared to the point in time suggested by a measured value of said second parameter.

Abstract: The subject matter disclosed herein relates to a method of reducing an amount of mercury discharged to an environment in a flue gas (12) generated by combustion of a fuel source. The method includes contacting the flue gas with a moist pulverous material upstream of a particle separator (24), mixing powdered activated carbon (PAC) in an amount between about 0.5 lb/MMacf and 10 lbs/MMacf with the flue gas (12) upstream of the particle separator (24), wherein the PAC interacts with at least a portion of mercury containing compounds in the flue gas (12), and separating the mercury containing compounds from the flue gas (12) containing the moist pulverous material and PAC, thereby reducing an amount of mercury in the flue gas (12).

Abstract: A method of removing SO3 from a flue gas of a boiler. The method includes the following steps: injecting chloride salts into a stream of the flue gas at a position located downstream of an air pre-heater—the position is selected so that the flue gas has a temperature at the position of substantially between 100° C. and 400° C.; reacting chloride salts with the SO3 to form a sulfate-containing reaction product; and collecting the sulfate-containing reaction product in a particulate collector downstream of the boiler. A purge stream from a wet flue gas desulfurization system may be used as a source of the chloride salts. Additional chlorides may be added to the purge stream as necessary.

Abstract: The subject matter disclosed herein relates to a method of reducing an amount of mercury discharged to an environment in a flue gas (12) generated by combustion of a fuel source. The method includes contacting the flue gas with a moist pulverous material upstream of a particle separator (24), mixing powdered activated carbon (PAC) in an amount between about 0.5 lb/MMacf and 10 lbs/MMacf with the flue gas (12) upstream of the particle separator (24), wherein the PAC interacts with at least a portion of mercury containing compounds in the flue gas (12), and separating the mercury containing compounds from the flue gas (12) containing the moist pulverous material and PAC, thereby reducing an amount of mercury in the flue gas (12).

Abstract: The subject matter disclosed herein relates to a method of reducing an amount of mercury discharged to an environment in a flue gas (12) generated by combustion of a fuel source. The method includes contacting the flue gas with a moist pulverous material upstream of a particle separator (24), mixing powdered activated carbon (PAC) in an amount between about 0.5 lb/MMacf and 10 lbs/MMacf with the flue gas (12) upstream of the particle separator (24), wherein the PAC interacts with at least a portion of mercury containing compounds in the flue gas (12), and separating the mercury containing compounds from the flue gas (12) containing the moist pulverous material and PAC, thereby reducing an amount of mercury in the flue gas (12).

Abstract: One embodiment of the present invention relates to a process for treating a flue gas stream (22) from a coal-fired boiler to reduce the amount of mercury contained therein. The process includes subjecting the flue gas stream (22) to a first wet scrubbing process for reducing the concentration of sulfur oxides therein and thereby producing a water-saturated flue gas stream (22) and subjecting the water-saturated flue gas stream to a second wet scrubbing process having an aqueous acidic solution comprising hydrogen peroxide to produce a flue gas having a reduced mercury content.

Abstract: Controlling the reductive capacity of an aqueous alkaline slurry (23) in a wet scrubber makes it possible to accurately control the mercury emission from the scrubber to a desired value. One method of controlling the reductive capacity of the slurry is to measure the reduction-oxidation potential (“redox potential”) of the aqueous alkaline slurry (23) and to add or remove substances that affect the redox potential and thus the reductive capacity of the slurry. In wet scrubbers in which limestone is used for absorption of acid gases and where a gypsum slurry is circulated, it has been found to be an attractive solution to control the amount of oxidation air blown into the scrubber in order to control the redox potential and thereby the mercury emissions.

Abstract: A method of removing SO3 from a flue gas of a boiler. The method includes the following steps: injecting chloride salts into a stream of the flue gas at a position located downstream of an air pre-heater—the position is selected so that the flue gas has a temperature at the position of substantially between 100° C. and 400° C.; reacting chloride salts with the SO3 to form a sulfate-containing reaction product; and collecting the sulfate-containing reaction product in a particulate collector downstream of the boiler. A purge stream from a wet flue gas desulfurization system may be used as a source of the chloride salts. Additional chlorides may be added to the purge stream as necessary.

Abstract: Controlling the reductive capacity of an aqueous alkaline slurry (23) in a wet scrubber makes it possible to accurately control the mercury emission from the scrubber to a desired value. One method of controlling the reductive capacity of the slurry is to measure the reduction-oxidation potential (“redox potential”) of the aqueous alkaline slurry (23) and to add or remove substances that affect the redox potential and thus the reductive capacity of the slurry. In wet scrubbers in which limestone is used for absorption of acid gases and where a gypsum slurry is circulated, it has been found to be an attractive solution to control the amount of oxidation air blown into the scrubber in order to control the redox potential and thereby the mercury emissions.

Abstract: A process for reducing an amount of sulfur trioxide present in a flue gas stream (20), including the steps of processing an alkaline material (24) to comprise a predetermined percentage of particles, based on the mass of alkaline material introduced into a flue gas stream (20), having a size less than a predetermined dimension and introducing the processed alkaline material (24) to the flue gas stream (20), wherein the processed alkaline material (24) reduces the amount of sulfur trioxide present in the flue gas stream (20).

Abstract: One embodiment of the present invention relates to a process for treating a flue gas stream (22) from a coal-fired boiler to reduce the amount of mercury contained therein. The process includes subjecting the flue gas stream (22) to a first wet scrubbing process for reducing the concentration of sulfur oxides therein and thereby producing a water-saturated flue gas stream (22) and subjecting the water-saturated flue gas stream to a second wet scrubbing process having an aqueous acidic solution comprising hydrogen peroxide to produce a flue gas having a reduced mercury content.

Abstract: Purification of gases from acid gas components according to the dry method means that the gas is contacted with an absorbent in a solid phase, which yields a relatively low reaction rate. In order to increase the reaction rate according to the invention, the gas is contacted with a mixture consisting partially of a solid absorbent phase and partially a liquid phase on the surface of the solid phase. At the purification of flue gases from sulphur dioxide hot gas is contacted with an absorption liquid in a drying apparatus, where evaporation of the water supplied and a reaction between sulphur dioxide and the absorption substance take place simultaneously, whereafter the solid product phase is separated from the gas in a dust separator and a slower, secondary absorption reaction is operative.

Abstract: A method of highly efficiently separating preferably low contents of gaseous mercury from a gas mixture, where the gas mixture is caused to contact a solid sorbent consisting of powdered calcium hydroxide, which in an atmosphere containing hydrogen chloride is to a certain part converted to calcium chloride. The temperature of the gas mixture is between 350.degree. K. and 550.degree. K. The contact between the gas and the sorbent preferably takes place in a fluidized bed, whereafter the sorbent is separated in a dust separator. The method is suitable for use at the separation of mercury occurring in flue gases, for example from refuse incinerators or in mercury-containing gases from process industries. At experiments with flue gas from a refuse incinerator the mercury content was reduced from 200 to 5 .mu.g of gaseous mercury/cubic meter flue gas.