A method for preparing adsorbent from residue after lignite extraction of humic acid

A humic acid and adsorbent technology, applied in chemical instruments and methods, other chemical processes, inorganic chemistry, etc., can solve the problems of large amount of alkali, high cost and complex process.

Active Publication Date: 2019-11-12
CHINA UNIV OF MINING & TECH
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

Using the liquid alkali in the residue after coal humic acid extraction, one-step method to prepare cheap and high-efficiency adsorbent, which overcomes the large amount of alkali used in the traditional alkali activation method to prepare activated carbon (alkali-coke ratio is about 3:1~4:1) , complicated process and high cost

Method used

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  • A method for preparing adsorbent from residue after lignite extraction of humic acid
  • A method for preparing adsorbent from residue after lignite extraction of humic acid
  • A method for preparing adsorbent from residue after lignite extraction of humic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Humic acid extraction:

[0023] Air-dried Pioneer lignite is used as raw material, pulverized by a coal mill, impurities are removed, sieved, and the 40-mesh undersize (coal powder) is sealed and collected. Table 1 shows the composition analysis of Pioneer lignite.

[0024] Table 1 Industrial analysis and elemental analysis of Xianfeng lignite

[0025]

[0026] Weigh 5 parts of 5g coal samples into a three-neck flask, add 150mL of NaOH solution with a mass percentage concentration of 2%, 3%, 4%, 5%, and 6% respectively, and store them at 90°C, 80°C, 70°C, Heating in water bath at 60°C and 50°C for 3h, 2.5h, 2h, 1h, 0.5h. The reacted solution is cooled and then centrifuged, and the supernatant liquid is evaporated to remove water, which is humic acid salt. The yields of humate at different alkali extraction concentrations are shown in Table 2. It can be seen that the yield of humate obtained when the NaOH concentration is 4% is the highest.

[0027] Table 2 Humat...

Embodiment 2

[0031] Pyrolysis:

[0032] Weigh 5g of 40-80 mesh air-dried pioneer lignite, and heat it in a water bath at 80°C for 1h in 150mL NaOH solution with a concentration of 4%. The solution after the reaction is cooled and centrifuged, and the precipitate is put into an oven for 105 o C dried for 2h. Take 3g of dry lignite residue and put it into the pyrolysis reaction tube, pass nitrogen as protective gas, and set the temperature rise rate of the temperature controller to be 10 o C / min, respectively at 760 o C and 940 oC pyrolysis at the end temperature of pyrolysis (also known as pyrolysis temperature in the examples), and the constant temperature time is 30 min. The pyrolyzed solid product is washed with deionized water to neutrality, and dried at high temperature to constant weight to finally obtain the carbonaceous adsorbent.

[0033] It has been verified by actual experiments that the dry lignite residue can be heated and pyrolyzed in the pyrolysis furnace under the prote...

Embodiment 3

[0042] Weigh 5g of air-dried vanguard lignite below 80 meshes, and add concentrations of 2%, 3%, 4%, and 5% respectively in 300mL NaOH solution, o C for 20 min in an ultrasonic water bath. The solution after the reaction is cooled and centrifuged, and the precipitate is put into an oven for 105 o C dried for 2 h. Take 3g of dry lignite residue and put it into the pyrolysis reaction tube, pass nitrogen as protective gas, and set the temperature rise rate of the temperature controller to be 10 o C / min at 900 o C pyrolysis temperature pyrolysis, constant temperature time is 20 min. Table 5 shows the iodine value, specific surface area, pore volume and average pore diameter of lignite residue pyrolysis coke after humic acid extraction with different alkali concentrations.

[0043] Table 5 Iodine value and pore structure parameters of residue pyrolysis coke after lignite humic acid extraction with different alkali concentrations

[0044] NaOH concentration / % Iodine...

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Abstract

The invention discloses a method for extracting humic acid from lignite and then using residues to prepare an adsorbent. An alkali dissolution and acid precipitation method is adopted to extract humic acid from lignite, pyrolysis is conducted on the residues at the temperature of 760-940 DEG C, a pyrolysis gas product is condensed and cooled to prepare tar and hydrogen-rich gas, a pyrolysis solid product is washed and dried to prepare a carbonaceous adsorbent, and graded conversion and utilization of the lignite are achieved. According to the method, the alkali liquor in the residues after the humic acid is extracted from the lignite is utilized, the carbonaceous adsorbent having large specific surface area and good adsorption property is prepared through high-temperature pyrolysis in a one-step mode, and the shortcomings of large alkali amount, complicated process and high cost of a traditional process for preparing activated carbon based on an alkali activation method are overcome. A byproduct tar contains little pyrolysis water, is easy to separate, high in yield, a byproduct raw coal gas has very high H2 and CO content, the CH4 content is low, and the produced gas serves as chemical raw gas after being purified and modified.

Description

technical field [0001] The invention relates to a coal comprehensive utilization technology, in particular to a method for preparing an adsorbent from the residue after humic acid is extracted from coal. Background technique [0002] With the massive mining of coal, my country's high-quality coal resources are gradually decreasing, but lignite resources are abundant but underutilized. The efficient use of abundant lignite resources has high economic and social value. Therefore, effectively improving the comprehensive utilization of lignite and developing towards high value-added products has gradually become a research hotspot. [0003] Lignite is an inferior fuel with high volatile content, high moisture, high ash content, low calorific value, low ash melting point, strong chemical reactivity, poor thermal stability, easy weathering and fragmentation, easy oxidation and spontaneous combustion, and is the coal with the lowest degree of coalification. Burning lignite directl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/33B01J20/20B01J20/30
CPCB01J20/20B01J2220/4887C01P2006/12C01P2006/14C01P2006/16
Inventor 杨小芹张双全岳晓明朱凯文赫帅
Owner CHINA UNIV OF MINING & TECH
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