Flue gas treatment method and flue gas treatment device capable of simultaneous desulfurization, de-nitration and mercury removal through magnesium oxide

A technology for desulfurization, denitrification, mercury removal, and flue gas treatment, which is applied in the field of wet absorption process, can solve the problems of economic cost limitation, secondary pollution, etc., and achieve the effect of increasing oxidation rate and sufficient oxidation

Inactive Publication Date: 2014-04-23
ZHEJIANG TIANLAN ENVIRONMENTAL PROTECTION TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method adds both Hg 0 The oxidant has added a stabilizer, which has certain restrictions on economic cost, and is also prone to secondary pollution

Method used

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  • Flue gas treatment method and flue gas treatment device capable of simultaneous desulfurization, de-nitration and mercury removal through magnesium oxide
  • Flue gas treatment method and flue gas treatment device capable of simultaneous desulfurization, de-nitration and mercury removal through magnesium oxide

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] With device and process of the present invention, at 5m 3 The flue gas denitrification process is simulated on the experimental simulation device of / h scale. Flue gas volume 5m 3 / h, the flue gas composition is as follows: O 2 5%, NO 200ppm, SO 2 500ppm, the rest is nitrogen, Hg concentration is 20μg / Nm 3 , the flue gas temperature is 150 degrees Celsius, and the pressure is 1 atmosphere. Ozone according to the molar ratio O 3 : The ratio of NO=1.1 is injected, the oxidation time in the static mixer is about 3 seconds, the oxidation rate of NO at the outlet can reach 90%, the concentration of the absorbed MgO slurry is 5%, and 0.1% of Na 2 S 2 o 3 As an oxidation inhibitor, combined with a spray absorption device, the number of spray layers is six, and the liquid-gas ratio is 5L / m 3 , the pH is controlled at 6.5, the desulfurization rate can reach 90%, the denitrification efficiency can reach 85%, and the mercury removal efficiency can reach more than 80%.

Embodiment 2

[0050] With device and process of the present invention, at 5m 3 The flue gas denitrification process is simulated on the experimental simulation device of / h scale. Flue gas volume 5m 3 / h, the flue gas composition is as follows: O 2 12%, NO 230ppm, SO 2 550ppm, Hg concentration 20μg / Nm 3 , and the rest is nitrogen, the flue gas temperature is 110 degrees Celsius, and the pressure is 1 atmosphere. Ozone according to the molar ratio O 3 : The ratio of NO=1.2 is injected, the oxidation time in the static mixer is about 3 seconds, the oxidation rate of NO at the outlet can reach 95%, the concentration of the absorbed MgO slurry is 10%, and 0.5% Na 2 S 2 o 3 As an oxidation inhibitor, the pH is controlled at 6.5. Combined with the bubbling absorption device, the desulfurization rate can reach 90%, the denitrification efficiency can reach more than 85%, and the mercury removal efficiency can reach more than 80%.

Embodiment 3

[0052] With the device and process of the present invention, the flue gas flow rate is 4000Nm 3 / h,O 2 9%, NO 250ppm, SO 2 500ppm, Hg concentration 20μg / Nm 3 , and the rest is nitrogen, the flue gas temperature is 90 degrees Celsius, and the pressure is 1 atmosphere. Ozone according to the molar ratio O 3 : The ratio of NO=1.2 is injected, the oxidation time in the static mixer is about 3 seconds, the oxidation rate of NO at the outlet can reach 95%, the concentration of the absorbed MgO slurry is 8%, and 0.5% dibutylphenol is added as the oxidation Inhibitor, combined with spray absorption device, the number of spray layers is six, and the liquid-gas ratio is 5L / m 3 , the pH is controlled at 6.5, the desulfurization rate can reach 95%, the denitrification efficiency can reach 90%, and the mercury removal efficiency can reach more than 80%.

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Abstract

The invention discloses a flue gas treatment method and a flue gas treatment device for simultaneous desulfurization, de-nitration and mercury removal through magnesium oxide. The flue gas treatment method comprises the following steps: (1) removing dust from boiler flue gas and then transmitting the boiler flue gas into a static mixer, spaying ozone into the static mixer at the same time, mixing and oxidizing the boiler flue gas with the ozone; (2) transmitting the mixed and oxidized mixture gas into an absorbing tower from the bottom part of the absorbing tower, circularly spraying magnesium oxide solution in the absorbing tower; and (3) exhausting the sprayed-absorbed flue gas from the top of the absorbing tower through a chimney. Due to the adoption of combination of oxidization with a gaseous oxidizing agent and absorbing with magnesium oxide solution, the effect of simultaneous desulfurization, de-nitration and mercury removal in one tower is realized, and furthermore, the effects of simultaneous desulfurization, de-nitration and mercury removal are all good.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to a treatment process for flue gas such as coal-fired boilers, especially the treatment involving simultaneous nitrogen oxides (NO x ), sulfur dioxide (SO 2 ) and mercury (Hg) coal-fired flue gas, the front-end ozone (O 3 ) oxidation combined with back-end magnesium oxide slurry (MgO) wet absorption process. Background technique [0002] The main methods of flue gas denitrification are selective catalytic reduction technology (SCR), selective non-catalytic reduction technology (SNCR), wet complexation absorption technology, oxidation-absorption technology, etc. SCR is currently the most commonly used denitrification method. Although this technology has high denitrification efficiency, the basic investment and operating costs are expensive. In addition, this technology has poor adaptability to medium and high-sulfur coal, and the sulfur components in the flue gas c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/75B01D53/76B01D53/80B01D53/60B01D53/64
Inventor 程常杰莫建松王岳军
Owner ZHEJIANG TIANLAN ENVIRONMENTAL PROTECTION TECH
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