Method for preparing biochar and hydrogen by utilizing anaerobic fermentation byproducts

Patent metadata

Field	Value
Publication number	US-2022017825-A1
Application number	US-201917298137-A
Country	US
Kind code	A1
Filing date	Oct 16, 2019
Priority date	Oct 16, 2019
Publication date	Jan 20, 2022
Grant date	—

Abstract

A method for preparing biochar and hydrogen by utilizing anaerobic fermentation byproducts, the method including: (1) mixing a first straw, seeding sludge and distilled water, and then carrying out anaerobic fermentation to obtain a mixed product after fermentation; (2) performing separation on the mixed product to obtain a second straw and biogas slurry; and (3) carbonizing the second straw to obtain biochar, and collecting gas after a pressurized catalytic reaction on the biogas slurry to obtain hydrogen.

First claim

1 . A method for preparing biochar and hydrogen by utilizing anaerobic fermentation byproducts, the method comprising:
mixing first straw, seeding sludge, and distilled water for anaerobic fermentation to obtain a fermented mixed product; separating fermented straw from the fermented mixed product to obtain second straw; separating and recovering a biogas slurry from the fermented mixed product; carbonizing the obtained second straw to obtain the biochar; and collecting gas after a pressurized catalytic reaction of the obtained biogas slurry.

2 . The method according to claim 1 , wherein:
the mass ratio of the seeding sludge to the first straw is (25-30):1; the mass ratio of the distilled water to the first straw is (10-20):1; the length of the first straw is 2-3 cm; the first straw is an air-dried straw; the second straw is washed and dried before the carbonization step; the mesh number of the second straw is 40-80 mesh.

3 . The method according to claim 1 , wherein:
the anaerobic fermentation is realized in an anaerobic fermentation tank; the seeding sludge is the discharged sludge from an anaerobic fermentation tank; in the anaerobic fermentation, the fermentation temperature is 20-25° C.; the fermentation time is 7-14 days; and the materials are stirred every 10-14 hours; during the anaerobic fermentation, an anaerobic environment is realized by introducing inert gas comprising nitrogen.

4 . The method according to claim 1 , wherein:
the carbonization step is realized in a pyrolytic carbonization device; the pyrolytic carbonization device comprises a high-temperature tube furnace; in the carbonization step, the high-temperature tube furnace has a carbonization temperature of 750-850° C. and a pyrolytic carbonization time is 50-70 min.

5 . The method according to claim 1 , wherein: the step of collecting gas after a pressurized catalytic reaction of the obtained biogas slurry comprises, after adding a catalyst to the biogas slurry, reacting under a pressurized condition, and then cooling and collecting gas.

6 . The method according to claim 5 , wherein:
the concentration of the catalyst is 2-5 g/L; the reaction pressure is 1.5-5.0 MPa.

7 . The method according to claim 6 , wherein: the reaction pressure is 2.5-3.0 MPa.

8 . The method according to claim 5 , wherein:
the reaction temperature is 150-250° C.; the reaction time is 2.5-3 hours.

9 . The method according to claim 8 , wherein:
the reaction temperature is 200-250° C.; the reaction time is 3 hours.

10 . The method according to claim 5 , wherein: the stirring speed is 200-300 r/min.

11 . The method according to claim 10 , wherein: the stirring speed is 200-250 r/min.

12 . The method according to claim 5 , wherein a method for catalyst preparation comprises: a supported nickel-based catalyst is prepared by an equal volume impregnation method, which is reduced in a hydrogen gas atmosphere to obtain a black powdery solid comprising the catalyst.

13 . The method according to claim 12 , wherein the method for catalyst preparation comprises:
1) the supported nickel-based catalyst is prepared by an equal volume impregnation method: nickel nitrate is added to distilled water and stirred for 15-25 min, then a catalyst carrier is added and stirred for 15-25 min, and dried at 85-95° C. and taken out to obtain a solid A; 2) under a hydrogen gas atmosphere, the solid A obtained in step 1) is reduced at 550-650° C. for 2.5-3.5 hours to obtain a black powdery solid B comprising the catalyst, wherein the Ni content in the supported nickel-based catalyst is 15-20 wt %.

14 . The method according to claim 5 , wherein:
the catalyst carrier is a CeO 2 carrier or Al 2 O 3 carrier, wherein the preparation method of the CeO 2 carrier comprises: cerium nitrate is baked at 550-650° C. for 1.5-2.5 hours to obtain a CeO 2 carrier; the biogas slurry and the catalyst are added to a reactor for reaction, the reactor comprising a micro-reactor equipped with means for heating, pressurizing and stirring; the cooling step in the cooling and collecting gas is realized by an ice bath cooling method.

15 . A biochar prepared by the method according to claim 1 , wherein the specific surface area of the biochar is 240-288 m 2 /g.

16 . A method comprising:
performing anaerobic fermentation of a mixture of straw, seeding sludge, and distilled water to obtain a fermented mixed product; and carbonizing fermented straw separated from the fermented mixed product, to produce biochar.

17 . The method of claim 16 , further comprising collecting gas from a pressurized catalytic reaction of biogas slurry separated from the fermented mixed product.

18 . The method of claim 16 , wherein:
the mass ratio of the seeding sludge to the straw is (25-30):1; the mass ratio of the distilled water to the straw is (10-20):1; the length of the straw is 2-3 cm.

19 . The method of claim 16 , wherein:
the carbonizing is realized in a pyrolytic carbonization device comprising a high-temperature tube furnace; in the carbonizing, the high-temperature tube furnace has a carbonization temperature of 750-850° C. and a pyrolytic carbonization time is 50-70 min.

20 . A biochar prepared by the method according to claim 16 , wherein the specific surface area of the biochar is 240-288 m 2 /g.

Assignees

• Univ Tianjin

Inventors

• Chen Guanyi
• Guo Xiang
• Mao Yurou
• Yan Beibei
• Zhang Yanbin
• Tao Junyu
• Li Wanqing
• Cheng Zhanjun
• Ma Wenchao

Classifications

• Y02E50/10

  Biofuels, e.g. bio-diesel · CPC title

• B01J23/83

  with rare earths or actinides · CPC title

• B01J23/755

  Nickel · CPC title

• B01J21/04

  Alumina · CPC title

• B01J37/18

  with gases containing free hydrogen · CPC title