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CN-116870863-B - Method for preparing mercury-removing adsorbent from brominated flame-retardant waste plastics and mercury-removing adsorbent

CN116870863BCN 116870863 BCN116870863 BCN 116870863BCN-116870863-B

Abstract

The invention belongs to the relevant technical field of solid waste recycling, and discloses a method for preparing a mercury-removing adsorbent from brominated flame-retardant waste plastics and the mercury-removing adsorbent, wherein the method comprises the steps of crushing the brominated flame-retardant waste plastics and drying to obtain a reaction raw material; the method comprises the steps of putting reaction raw materials into a pyrolysis reactor, carrying out pyrolysis under inert atmosphere to obtain solid residues, putting the solid residues into a low-temperature plasma reactor, carrying out discharge between two electrodes to modify the solid residues, and crushing and grinding the obtained modified solid residues to obtain the mercury-removing adsorbent. The invention adopts brominated flame-retardant waste plastics as raw materials and prepares the mercury-removing adsorbent through low-temperature plasma modification, the raw materials are electronic waste, the production amount is large, the cost is low, the preparation and modification are simple, the two problems of flue gas mercury removal and electronic waste recycling in coal-fired power plants can be solved, and the mercury-removing efficiency is obviously improved by adopting pyrolysis reaction to prepare and adopting the low-temperature plasma modified mercury-removing adsorbent.

Inventors

  • SUN LUSHI
  • WAN GAN
  • XU LINLIN
  • CHEN TAO

Assignees

  • 华中科技大学

Dates

Publication Date
20260505
Application Date
20230712

Claims (9)

  1. 1. The method for preparing the mercury-removing adsorbent from the brominated flame-retardant waste plastics is characterized by comprising the following steps of: S1, smashing brominated flame-retardant waste plastics, and drying to obtain a reaction raw material; S2, placing the reaction raw materials into a pyrolysis reactor, and carrying out pyrolysis reaction in an inert atmosphere to obtain reacted solid residues; S3, placing the solid residues into a low-temperature plasma reactor, and modifying the solid residues through discharge between two electrodes of the low-temperature plasma reactor; S4, crushing and grinding the obtained modified solid residues to obtain a mercury-removing adsorbent; The low-temperature plasma reactor in the step S3 is a space dielectric barrier discharge reactor, the alternating current frequency is 6.5-8.0kHz, the peak voltage is 8.0-12.0kV, and the modification time is 30-60min.
  2. 2. The method for preparing the mercury-removing adsorbent from the brominated flame retardant waste plastic according to claim 1, wherein the brominated flame retardant waste plastic is brominated epoxy resin waste plastic, brominated flame retardant ABS plastic, brominated flame retardant HIPS plastic or a mixture thereof.
  3. 3. The method for preparing mercury-removing adsorbent from brominated flame-retardant waste plastics according to claim 1, wherein the particle size of the powder obtained by pulverizing the brominated flame-retardant waste plastics in S1 is 100 μm to 150 μm.
  4. 4. The method for preparing the mercury-removing adsorbent from the brominated flame-retardant waste plastics according to claim 1, wherein the reaction condition of the pyrolysis reaction in the S2 is that the temperature rising rate of 10 ℃ per minute is raised to 500-700 ℃, the reaction pressure is normal pressure, and the heat preservation time is 1h.
  5. 5. The method for preparing the mercury-removing adsorbent from the brominated flame-retardant waste plastics according to claim 1, wherein the inert atmosphere in S2 is nitrogen, and the carrier gas flow is 0.2L/min-0.5L/min.
  6. 6. The method for preparing a mercury removal adsorbent from brominated flame retardant waste plastics as claimed in claim 1, wherein the particle size of the mercury removal adsorbent in S4 is 50 μm to 75 μm.
  7. 7. The method for preparing a mercury removal adsorbent from brominated flame retardant waste plastics as claimed in any one of claims 1 to 6, further comprising: S5, placing the mercury removal adsorbent into a mercury removal performance test system, and carrying out mercury removal performance test verification on the mercury removal adsorbent; The mercury removal performance test system comprises an inert gas storage tank, a flowmeter, a mercury generator, a mercury removal reactor, a temperature controller, a gas mixing bottle and a mercury analyzer, wherein the inert gas storage tank is respectively connected with a first branch and a second branch, the flowmeter is respectively arranged on the first branch and the second branch, the mercury generator is arranged on the first branch, the first branch and the second branch are respectively connected to the gas mixing bottle, the gas mixing bottle is respectively connected with the mercury removal reactor and the mercury analyzer, the mercury removal reactor is connected to the mercury analyzer, valves are respectively arranged on the first branch, the second branch, the branch where the mercury removal reactor is located, and between the gas mixing bottle and the mercury analyzer, and the mercury generator and the mercury removal reactor are respectively connected with the temperature controller.
  8. 8. The method for preparing the mercury removal adsorbent from the brominated flame retardant waste plastic as set forth in claim 7, wherein S5 specifically comprises: placing the mercury removal adsorbent into a mercury removal reactor, preparing mercury simple substances with different concentrations through the mercury generator, and performing mercury removal performance tests of a plurality of groups of mercury simple substances with different mercury concentrations; For each group of mercury removal performance tests, obtaining mercury removal efficiency according to the initial elemental mercury concentration and the elemental mercury concentration after adsorption; And analyzing and judging the mercury removal performance of the mercury removal adsorbent according to the mercury removal efficiency obtained by a plurality of groups of mercury removal performance tests.
  9. 9. A mercury removal adsorbent prepared by the method of preparing mercury removal adsorbent using brominated flame retardant waste plastics according to any one of claims 1-8.

Description

Method for preparing mercury-removing adsorbent from brominated flame-retardant waste plastics and mercury-removing adsorbent Technical Field The invention belongs to the technical field of solid waste recycling, and particularly relates to a method for preparing a mercury-removing adsorbent from brominated flame-retardant waste plastics and the mercury-removing adsorbent. Background With the continuous growth of global population and economy, the continuous development of urban process and electronic industry and the continuous improvement of living standard, people have greater and greater demands on electronic products, the updating and iteration speed of the electronic products is faster and faster, and the generated electronic garbage is more and more. The brominated flame-retardant waste plastic is the main part of the electronic waste and occupies 30 percent of the total amount of the electronic waste. The brominated flame-retardant waste plastic is added with a large amount of brominated flame retardants due to the flame-retardant requirement, the bromine content reaches 20wt.%, and the direct incineration treatment can discharge a large amount of toxic substances such as hydrogen bromide, brominated dioxin and the like, so that serious environmental problems are caused. Therefore, the method for recycling brominated flame-retardant waste plastics has good popularization prospect and important significance. On the other hand, mercury pollution has become a global environmental problem, and prevention and control of mercury pollution have been widely paid attention both at home and abroad. Coal-fired power plants are the most dominant source of mercury emissions, which is present in the flue gas of coal-fired power plants in three main forms, elemental mercury (Hg 0), oxidized mercury (Hg 2+), and particulate mercury (Hg p). Oxidized mercury (Hg 2+) and granular mercury (Hg p) can be efficiently removed by wet desulfurization (WFGD) equipment, an electrostatic precipitator (ESP) or a bag-type dust collector (FF). Elemental mercury (Hg 0) is highly volatile and is almost insoluble in water and difficult to remove by a flue gas aftertreatment device. Removal of elemental mercury is a major and difficult problem in mercury emission control technologies. The existing flue activated carbon injection method (ACI) is the most mature and feasible technology for reducing mercury emission of the coal-fired power plant at present, and activated carbon is adopted as an adsorbent to adsorb and remove mercury. However, the existing mercury removal adsorbent adopts active carbon with high consumption (the carbon/mercury ratio is 2000-15000), and has the disadvantages of high regeneration difficulty and high raw material cost. Disclosure of Invention Aiming at the defects or improvement demands of the prior art, the invention provides a method for preparing a mercury-removing adsorbent from brominated flame-retardant waste plastics and the mercury-removing adsorbent, solves the problems of high regeneration difficulty and high raw material cost of the existing mercury-removing adsorbent by adopting activated carbon, realizes the preparation of the mercury-removing adsorbent by taking electronic garbage as a raw material, and has simple preparation and modification. In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a mercury-removing adsorbent from brominated flame retardant waste plastics, comprising: S1, smashing brominated flame-retardant waste plastics, and drying to obtain a reaction raw material; S2, placing the reaction raw materials into a pyrolysis reactor, and carrying out pyrolysis reaction in an inert atmosphere to obtain reacted solid residues; S3, placing the solid residues into a low-temperature plasma reactor, and modifying the solid residues through discharge between two electrodes of the low-temperature plasma reactor; S4, crushing and grinding the obtained modified solid residues to obtain the mercury-removing adsorbent. According to the method for preparing the mercury-removing adsorbent by using the brominated flame-retardant waste plastics, the brominated flame-retardant waste plastics are brominated epoxy resin waste plastics, brominated flame-retardant ABS plastics, brominated flame-retardant HIPS plastics or a mixture thereof. According to the method for preparing the mercury-removing adsorbent by using the brominated flame-retardant waste plastics, the particle size of the powder obtained after the brominated flame-retardant waste plastics are crushed in the S1 is 100-150 mu m. According to the method for preparing the mercury-removing adsorbent by the brominated flame-retardant waste plastics, the reaction condition of the pyrolysis reaction in S2 is that the temperature rising rate of 10 ℃ per minute is raised to 500-700 ℃, the reaction pressure is normal pressure, and the heat preservation time is 1h. According