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Method for reducing emission of heavy metal chromium in burning process

A combustion process, heavy metal technology, applied in separation methods, other chemical processes, alkali metal compounds, etc., can solve the problems of little change, low capture efficiency, reduction, etc., and achieve high Cr removal efficiency, simple treatment method, and easy The effect of promotion

Active Publication Date: 2018-01-05
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In 1997, Zeng Hancai and others used flotation to reduce the discharge of heavy metal Cr in coal. This method achieved good results in reducing the total amount of heavy metal chromium in some coal types, but because of the fine Particles are enriched, and the capture efficiency of air pollution devices for fine particles is very low, so the concentration of heavy metal chromium in the flue gas at the outlet of air pollution devices has not decreased in a corresponding proportion, and even has little change in some cases
In 2014, Wu Peidong et al. added bentonite, zeolite, calcium oxide and alumina to control the emission of heavy metal Cr during solid waste incineration, but the control effect was not ideal, and calcium oxide would lead to a large amount of highly toxic hexavalent chromium in solid ash. Formation, hexavalent chromium is easily leached out to pollute water and soil in the process of fly ash utilization
[0005] Yu Dezhong et al. "Synthesis of Nanoscale Iron Oxide and Its Adsorption Properties of Hexavalent Chromium" used nanoscale iron oxide as an adsorbent to adsorb Cr(VI) ions in solution, but it mainly used synthesized nanoscale iron oxide It has a developed specific surface area and rich micropore size for physical adsorption, which is different from the principle of gas-solid adsorption in high-temperature flue gas

Method used

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  • Method for reducing emission of heavy metal chromium in burning process
  • Method for reducing emission of heavy metal chromium in burning process

Examples

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Effect test

Embodiment 1

[0038] Embodiment 1, carry out combustion experiment to certain low rank coal, adjust the coal feeding rate of the coal feeder to be 5g / min (by controlling the coal feeding rate and the sorbent injection rate, the desorption efficiency of Cr can be effectively guaranteed, and the waste of raw materials can be avoided ), at a place where the tail flue gas is 1000°C, spray Fe with a particle size of 5μm-75μm at a rate of 0.25g / min 2 o 3 Particles, experiment for 40min. After the collection experiment, the ash sample was digested to measure its Cr content and form, Fe 2 o 3 The capture rate of Cr reaches 88%, and the hexavalent Cr in the ash after combustion is reduced by 52%.

Embodiment 2

[0039] Example 2: Carry out a combustion experiment on a certain low-rank coal, adjust the coal feeding rate of the coal feeder to 5g / min, and inject the coal with a particle size of 5μm- 75μm MgO adsorbent, experiment for 40min. After the collection experiment, the ash sample was digested to measure its Cr content and form. The capture rate of Cr by MgO reached 73%, and the hexavalent Cr in the ash after combustion decreased by 49%.

Embodiment 3

[0040] Example 3, conduct a combustion experiment on a certain low-rank coal, adjust the coal feeding rate of the coal feeder to 5g / min, and inject the coal with a particle size of 5μm- 75μm CaO adsorbent, experiment for 40min. After the collection experiment, the ash sample was digested to measure its Cr content and form. Although the capture rate of Cr by CaO reached 86%, the highly toxic hexavalent Cr in the ash increased by nearly 4 times after combustion.

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Abstract

The invention discloses a method for reducing emission of heavy metal chromium in a burning process. The method comprises the following steps: injecting 1g / Nm<3> to 20g / Nm<3> of main adsorbent based on Fe or Mg into tail flue gas of a high temperature (800 to 1100 DEG C) of a burning apparatus, wherein the adsorbent is solid powder, and a particle size of the adsorbent is 5 to 100 micrometers. Byvirtue of the chemical reaction and physical adsorption effect, Cr in the flue gas is adsorbed and can be converted into solid particles with an aerodynamic size being greater than 2.5 micrometers atthe high temperature, so that the Cr can be easily removed by a dust removal apparatus, and the generation of highly-toxic hexavalent chromium compounds in the ash can be inhibited. Gaseous toxic andharmful substances are converted to large-particle solids insoluble in water, so that the capturing and harmless and recycling treatment can be facilitated.

Description

technical field [0001] The invention belongs to the combustion pollutant discharge control technology, in particular to a method for reducing the discharge of heavy metal Cr in the combustion process. Background technique [0002] The main valence states of Cr are trivalent and hexavalent. Excessive intake of trivalent chromium can lead to diseases of the human body’s antioxidant system, such as high blood pressure, diabetes and so on. Hexavalent chromium is highly toxic, and its toxicity is about 100 to 1000 times that of trivalent chromium. It is easily absorbed by the human body. It can be absorbed by the human body through the digestive tract, respiratory tract, skin and mucous membranes, etc., which can lead to pharyngitis, bronchitis, dermatitis, etc. Diseases, when ingested in excess, can cause gastric ulcers, intestinal ulcers, and damage to kidney and liver functions, leading to cancer. [0003] Coal burning, garbage and sludge incineration are one of the main caus...

Claims

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Application Information

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IPC IPC(8): B01D53/83B01D53/64B01J20/06B01J20/28
Inventor 陈娟赵小平李箫玉董卉牛胜利韩奎华路春美
Owner SHANDONG UNIV
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