Oxidizing method for removing gaseous elemental mercury in boiler fume

A technology for boiler flue gas and elemental mercury is applied in the field of flue gas purification, which can solve the problems of unknown environmental impact, low system efficiency, and large impact on the quality of activated carbon, so as to reduce production and operation costs, simple production process, and discharge effect. Good results

Inactive Publication Date: 2010-05-12
NANJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The technical feature described by this patented technology allows for effective removal of harmful gases from exhaust streams while reducing environmental concerns associated with their disposing (the problem being addressed). It achieves these benefits through controllable reduction of certain metals like arsenic and selenium that contribute towards air quality issues such as acid rain caused by burning fossil fuels at coal plants.

Problems solved by technology

This patents discusses different ways to reduce the concentration levels of certain elements like selenium and chromium in industrial processes due to their negative effects on both humans and animals. Current solutions involve either removing them altogether or treating exhaust gases containing those elements before they escape into the surrounding environments. However, existing techniques require expensive materials and cannot efficiently achieve this target level.

Method used

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  • Oxidizing method for removing gaseous elemental mercury in boiler fume
  • Oxidizing method for removing gaseous elemental mercury in boiler fume
  • Oxidizing method for removing gaseous elemental mercury in boiler fume

Examples

Experimental program
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Effect test

Embodiment 1

[0053] In Example 1, the effects of dielectric barrier discharge plasma catalytic oxidation and removal of elemental mercury were tested under various simulated flue gas atmospheres. Including tests for the following conditions:

[0054] 1) simulated flue gas CO 2 / H 2 O / O 2 / N 2 / Hg atmosphere, the total simulated flue gas flow rate is 3.5L.min -1 , nitrogen is the balance gas, the concentration of carbon dioxide is 8.5%, the concentration of water vapor is 5%, the concentration of oxygen is 4.5%, and the concentration of mercury is kept at 22.3μg.Nm -3 Around, the discharge voltage is 6kV.

[0055] When the dielectric barrier discharge plasma reactor is energized and the space gas is broken down and discharged, the concentration of elemental mercury drops rapidly to 2.2-2.4 μg.Nm -3 about. When the power is turned off, the concentration of elemental mercury in the flue gas quickly returns to the initial concentration level. The oxidation removal rate of elemental mer...

Embodiment 2

[0058] In Example 2, in a real flue gas atmosphere, the effect of using dielectric barrier discharge plasma to catalyze oxidation and remove elemental mercury was tested. Including tests for the following conditions:

[0059] The total simulated flue gas flow rate is 10000m 3 .h -1 , the fuel is bituminous coal, the flue gas temperature is 160°C, and the tested mercury concentration is kept at 12.5μg.Nm -3 Around, other main gas components in the flue gas are: SO2: 1050ppm, CO2: 9.4%, O2: 4.7%, HCl: 122ppm, and the discharge voltage is 2-7kV. It can be seen that with the increase of voltage, the removal efficiency of elemental mercury can reach more than 85%, and the voltage rises to a certain level, which has little effect on the removal efficiency. Therefore, the energy consumption of flue gas mercury removal devices of different boilers can be proposed. optimized design.

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Abstract

The invention discloses an oxidizing method for removing gaseous elemental mercury in boiler fume. According to the method, a medium is utilized to stop a plasma reactor from discharging and generating plasma gas; boiler fume is allowed to flow through a plasma gas region, so that gaseous elemental mercury is converted into mercury ions; and the mercury ions are captured by a dust removing and desulfurizing unit of a downstream flue, thereby realizing cooperative fume purification. The method can control mercury pollution in fume without secondary pollution, comprehensively control gaseous nulvalent mercury in fume, and convert the gaseous nulvalent mercury into bivalent ferrum. The method can be combined with the traditional pollutant control device of boilers to control the mercury emission, thereby reducing the initial investment and saving the operation cost. Since the plasma field can be produced immediately after electrification and can promote the oxidization of SO2 and NOX in the fume, the method can cooperatively purify multiple pollutants. The method adopts a medium to stop discharge and has the advantages of favorable discharge effect, convenient operation and low energy consumption.

Description

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Claims

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Application Information

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Owner NANJING NORMAL UNIVERSITY
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