Method for efficiently removing elemental mercury in flue gas

A technology for elemental mercury and flue gas, applied in separation methods, chemical instruments and methods, gas treatment, etc., can solve the problem that commercial activated carbon has a small mercury adsorption capacity and rate, is difficult to remove by flue gas treatment devices, and is difficult to meet mercury emissions. Standard and other issues, to achieve excellent mercury removal effect, reduce mercury re-release, and improve the scope of application.

Inactive Publication Date: 2019-04-12
CENT SOUTH UNIV
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  • Abstract
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Problems solved by technology

[0004] Among the three forms of mercury, particulate mercury (Hg p ) has low volatility and can be effectively removed by the flue gas dust collector. In addition, oxidized mercury (Hg 2+ ) can be synergistically removed by existing flue gas desulfurization devices due to its water solubility, but elemental mercury (Hg 0 ) is difficult to be removed by existing flue gas treatment devices due to its insolubility in water and high volatility. Therefore, Hg in flue gas 0 The effective removal of mercury is a difficult problem in the field of mercury pollution reduction
Although activated carbon adsorbent is a relatively mature commercial mercury removal medium, the mercury removal efficiency is restricted by coal quality and flue gas conditions, and the cost is high, the consumption is large, and the operation cost is expensive; mercury on the surface of activated carbon is mainly physical Adsorption, when activated carbon is exposed to the environment, it is easier to release it and cause secondary pollution to the environment; and the mercury adsorption capacity and rate of commercial activated carbon are small, it is difficult to meet the increasing mercury emission standards in the future

Method used

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  • Method for efficiently removing elemental mercury in flue gas

Examples

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Embodiment 1

[0029] Weigh 50 mg of natural copper selenium (CuSe), whose BET specific surface area is 0.18 m 2 g -1 , passed through a 100-mesh sieve after drying, and placed in a cylindrical quartz glass fixed-bed reactor with a length of 10 cm and an inner diameter of 1 cm. Mercury produced by mercury permeation tube, Hg 0 Initial concentration 75 μg·m -3 , and use 1 L min -1 Nitrogen acts as the carrier gas through the CuSe adsorbent, and the simulated flue gas flow rate is 0.15m s -1 , use the VM3000 mercury detector to monitor the Hg at the inlet and outlet of the reactor 0 concentration. When the reaction temperature is room temperature, for Hg 0 The adsorption efficiency is 100%.

Embodiment 2

[0031] Weighing synthetic molybdenum selenide (MoSe 3 ) 10 mg, the synthesis method is: mix and dissolve selenium powder and sodium molybdate in 14 v% hydrazine hydrate solution, transfer the solution to the reaction kettle and o Under the condition of C, react for 12 hours, pass through a 100-mesh sieve after centrifugal drying, and the BET specific surface area can reach 101.3 m 2 g -1 . The synthesized MoSe 3 Weigh 10 mg and place it in a cylindrical quartz glass fixed-bed reactor with a length of 10 cm and an inner diameter of 1 cm. Mercury produced by mercury permeation tube, Hg 0 Initial concentration 1000 μg·m -3 , and use 1 L min -1 Nitrogen acts as a carrier gas through MoSe 3 Adsorbent, the simulated flue gas flow rate is 0.5 m s -1 , use the VM3000 mercury detector to monitor the concentration of elemental mercury at the inlet and outlet of the reactor, and the reaction temperature is 50 o C, in the case of flue gas with high mercury content, Hg 0The remo...

Embodiment 3

[0033] Weigh 200 mg of synthetic zinc selenite (ZnSe), the synthesis method is as follows: mix and dissolve zinc sulfate and sodium selenate in equimolar ratio in 10 v% hydrazine hydrate solution, and place in a reaction kettle at 150 o Reaction under C conditions for 12 hours, after centrifugal drying, 100-mesh sieve, its BET specific surface area reached 202 m 2 g -1 . 200 mg of the synthesized ZnSe was weighed and placed in a cylindrical quartz glass fixed-bed reactor with a length of 10 cm and an inner diameter of 1 cm. Hg generation via mercury permeation tube 0 , Hg 0 Initial concentration 60 μg·m -3 , and use 1 L min -1 Nitrogen acts as a carrier gas through the ZnSe adsorbent, while adding simulated flue gas components of 300 ppm NO, 400 ppm SO 2 , 30ppm HCl and 8% H 2 O, use a VM3000 mercury detector to monitor the concentration of elemental mercury at the inlet and outlet of the reactor. The reaction temperature is 200°C, Hg 0 The extraction efficiency reac...

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Abstract

The invention discloses a method for efficiently removing elemental mercury in flue gas. A metal selenized mineral is utilized as a demercuration medium, contains selenium-copper ores (CuSe), selenium-molybdenum ores (MoSex) and selenium-zinc ores (ZnSe) and is in contact with mercury in the flue gas, in a fixed bed reactor or a jet tower, and accordingly volatile gaseous elemental mercury in theflue gas is converted into stable solid mercury selenide; the natural reserve of the metal selenized mineral is large, synthesis is relatively easy, and metal selenized mineral has very high mercury adsorption capacity and adsorption rate. Therefore, the method has the advantages of high efficiency, low investment, simple, easy operation and the like and has wide market application prospects.

Description

technical field [0001] The invention belongs to the technical field of environmental pollution prevention and purification, and in particular relates to a method for efficiently removing elemental mercury in flue gas. Background technique [0002] Mercury has been identified as a global environmental pollutant by the United Nations Environment Program (UNEP) because of its high toxicity, high volatility, easy migration and bioaccumulation. According to the latest 2018 global mercury pollution report released by UNEP, the atmosphere The mercury emitted due to human activities in China reaches 2,500 tons / year, far exceeding the mercury emitted into nature due to natural activities. In August 2017, the global Minamata Convention came into effect in its 128 signatory countries. Its purpose is to limit the increasing man-made mercury pollution discharge, which has received wide attention and recognition from the international community. [0003] In 2011, my country formulated th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/02B01J20/02
CPCB01D53/02B01D2253/112B01D2257/602B01D2258/0283B01J20/0262
Inventor 李海龙杨泽群
Owner CENT SOUTH UNIV
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