Method for producing biogas from waste liquid/residue after diosgenin extraction from Dioscorea composita by aluminum chloride

Patent metadata

Field	Value
Publication number	US-11920176-B2
Application number	US-202018026593-A
Country	US
Kind code	B2
Filing date	Nov 27, 2020
Priority date	Oct 10, 2019
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

Disclosed is a method for producing biogas from a waste liquid/residue after diosgenin extraction by aluminum chloride. Specifically, in a fermentation vessel, an anaerobic sludge and a waste residue from diosgenin extraction by aluminum chloride are added at a volatile solids ratio of (1-3):(1-2), or a seeding sludge and a diosgenin waste liquid are added with an organic loading having a VS:COD ratio of (1-2):(1-2); and then the above components are fermented at 35-37° C. for 5-25 d such that biogas is produced. According to the method of the present invention, the maximum cumulative biogas production rates are 255.4 mL/g VS for waste residue and 326.9 mL/g COD for waste liquid, and throughout the fermentation period, ammoniacal nitrogen values are below 1500 mg/L and pH variation is within the normal range, and the COD removal rate for the fermentation broth is 91.11%.

First claim

What is claimed is:

1. A method for producing biogas from a waste liquid/residue after diosgenin extraction by aluminum chloride, comprising:
adding an anaerobic sludge and a waste residue from diosgenin extraction by aluminum chloride with an organic loading having a volatile solids ratio of (1-3):(1-2) or adding a seeding sludge and a diosgenin waste liquid with an organic loading having a VS:COD ratio of (1-2):(1-2) in a fermentation vessel, wherein the VS is the volatile solid of the seeding sludge, and the COD is a chemical oxygen demand of the diosgenin waste liquid; and
subjecting the above components to fermentation at 35° C.-37° C. for 5-25 days to produce biogas,
wherein the fermentation is performed with stirring for 1-2 min at intervals of 5-6 min.

2. The method according to claim 1 , wherein the fermentation lasts for 5-15 days.

3. The method according to claim 1 , wherein the seeding sludge has a pH value of 7.3-7.8 and a COD of 1000-1200 mg/L.

4. The method according to claim 1 , wherein the volatile solids ratio of the anaerobic sludge to the waste residue from diosgenin extraction by aluminum chloride is 3:1; the VS:COD ratio of the seeding sludge to the diosgenin waste liquid is 1:1.

5. The method according to claim 1 , wherein the diosgenin extraction by aluminum chloride is performed as follows: putting a dried Dioscorea powder to a reaction still, and adding a ternary biphase solution consisting of an aluminum chloride aqueous solution, ethanol and petroleum ether, and mixing well, performing a reaction for 0.5-3.0 h at 130-180° C., and filtering a reaction liquid to remove residues, isolating a petroleum ether layer, then performing rotary evaporation, and performing recrystallization to obtain diosgenin.

6. The method according to claim 5 , wherein the reaction is performed at 140-170° C. for 1-2.5 h.

7. The method according to claim 5 , wherein the aluminum chloride aqueous solution has a concentration of 1.25 g/L-15 g/L.

8. The method according to claim 5 , wherein the ethanol/aluminum chloride aqueous solution/petroleum ether solution has a volume ratio of (6-15):16:(8-32).

9. The method according to claim 5 , wherein an additive amount of the Dioscorea powder to the reaction system is 18-20 g/L.

Assignees

• Univ South China Agricult

Inventors

• Xie Jun
• Bi Guican
• Zhang Hongdan

Classifications

• C12P5/023 Primary

  Methane · CPC title

• C07J71/0005

  Oxygen-containing hetero ring · CPC title

• Y02E50/30

  Fuel from waste, e.g. synthetic alcohol or diesel · CPC title