Biomimetic enzyme absorbent for removing elemental mercury in flue gas and its preparation method and application

Abstract

The invention provides a bionic enzyme absorbent for removing element mercury in flue gas, a preparation method of the bionic enzyme absorbent and an application. The bionic enzyme absorbent comprises, 0.04-0.80% of oxidative additives according to weight percentage ratio, 20-200ppm of bionic enzyme and 7.5-17.5% of phosphate buffers according to volume percentage ratio, and a pH (potential of hydrogen) value of the absorbent is 9-10. The preparation method of the bionic enzyme absorbent includes the steps: weighing an appropriate quantity of components, and adding the weighed bionic enzyme into the phosphate buffers to obtain mixed liquid; adding the weighed oxidative additives into the mixed liquid, uniformly stirring mixture, and adding NaOH to adjust a pH value of the mixed liquid to be 9-10 to obtain the absorbent. According to the bionic enzyme absorbent, the bionic enzyme serves as a catalyst, the element mercury in the flue gas is rapidly oxidized, and ion-state mercury can be further converted into solid-state oxidation mercury, so that immobilized removal of the element mercury is achieved.

Description

technical field [0001] The invention belongs to the technical field of environmental protection and relates to an absorbent and its preparation method and application, in particular to a biomimetic enzyme absorbent for removing elemental mercury in flue gas and its preparation method and application. Background technique [0002] In recent years, due to the concealment, high volatility, easy migration, high bioaccumulation and potential persistent harm of trace elements, especially mercury, in environmental pollution, it has attracted widespread attention from the international community. The total amount of mercury emitted into the atmosphere in the world is about 5000t per year, of which 4000t is the result of man-made, and the mercury emission in the process of coal combustion accounts for more than 30%. In order to protect the environment and achieve sustainable development, the state requires coal-fired boilers to control the emission mass concentration of mercury and i...

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Problems solved by technology

Dennis Lu et al. used Fenton (H 2 o 2 +Fe 2+ ) reagent was tested for Hg in coal-fired flue gas 0 The removal study, the results show that the solution pH value on Hg 0 The oxidation effect is significant, and at low pH values ​​H 2 o 2 Very prone to disproportionation reactions, resulting in a large amount of H 2 o 2 Decomposition, low utilization rate; under the condition of pH 1.0-3.0, use high concentration of H 2 o 2 , can only get an average of 75% of Hg 0 Oxidation efficiency, and in the process of mercury removal, due to the low pH value, it is easy to corrode the equipment

Yewen Tan et al. conducted a pilot study on the removal of mercury from coal-fired flue gas based on the Fenton reaction on the vertical combustion research facility of the Canadian Minerals and Energy Technology Center, but due to Fe 3+ Hydrolysis reaction occurs in the pH range of desulfurization slurry (5.2-5.6), resulting in flocculent precipitation, which makes the Fenton reaction system lose its oxidation activity, so it is not possible to directly add Fenton reagent to the desulfurization system to achieve mercury removal

[0005] To overcome H 2 o 2 or Fenton's reagent in the oxidation of Hg 0 And problems in engineering application, such as severe corrosion and easy decomposition of equipment caused by low pH, and a large amount of iron sludge in the reaction process, etc.

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