US 12,479,732 B2
Method for hydrolyzing cellulose into sugar to produce spherical capacitive carbon
Qishi Du, Nanning (CN); Siyu Long, Nanning (CN); Peiduo Tang, Nanning (CN); and Xuequan Xian, Nanning (CN)
Assigned to GUANGXI ACADEMY OF SCIENCES, Nanning (CN)
Filed by GUANGXI ACADEMY OF SCIENCES, Nanning (CN)
Filed on Jul. 29, 2022, as Appl. No. 17/877,036.
Claims priority of application No. 202111332258.8 (CN), filed on Nov. 11, 2021.
Prior Publication US 2023/0143916 A1, May 11, 2023
Int. Cl. C01B 32/318 (2017.01); C01B 32/348 (2017.01); C01B 32/378 (2017.01); C01B 32/384 (2017.01); C13K 1/04 (2006.01); H01G 11/32 (2013.01)
CPC C01B 32/318 (2017.08) [C01B 32/348 (2017.08); C01B 32/378 (2017.08); C01B 32/384 (2017.08); C13K 1/04 (2013.01); H01G 11/32 (2013.01); C01P 2004/03 (2013.01); C01P 2004/32 (2013.01); C01P 2004/50 (2013.01); C01P 2006/40 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for hydrolyzing cellulose into sugar to produce spherical capacitive carbon, comprising the following steps:
step 1, crude cellulose pretreatment: soaking and stirring a crude cellulose raw material in a dilute sulfuric acid solution, filtering, rinsing filter residues with clean water until neutral, and drying the filter residues to obtain cellulose;
step 2, alkaline hydrolysis of cellulose: adding the cellulose obtained in step 1 into a lye, cooking the cellulose at 120-150° C. for 6-10 h, and partly hydrolyzing the cellulose into sugar;
step 3, separation of the cellulose from a hydrolyzed sugar liquor: subjecting a hydrolysate obtained in step 2 to solid-liquid separation, washing filter residues with water and drying to obtain purified cellulose;
step 4, drying of an alkali-containing hydrolyzed sugar: using a filtrate separated in step 3 as an alkali-containing hydrolyzed sugar liquor, and evaporating and drying the alkali-containing hydrolyzed sugar liquor to obtain the alkali-containing hydrolyzed sugar;
step 5, sintering of spherical capacitive carbon: supplementing the alkali-containing hydrolyzed sugar with an activator and a co-activator, grinding, stirring and mixing evenly, heating a resulting mixture to 700-800° C. in an inert atmosphere, and carbonizing-activating for 60-90 min to form a spherical capacitive carbon agglomerate;
step 6, capacitive carbon post-processing: crushing the spherical capacitive carbon agglomerate, soaking in hot water, filtering, reserving a filtrate, pickling and washing filter residues with water, drying and grinding to obtain a finished product of spherical capacitive carbon; and
step 7, alkali recycling: drying a hot water soaked filtrate in the capacitive carbon post-processing in step 6, recovering the alkali, and recycling the alkali used in the alkaline hydrolysis of cellulose in step 2 and/or the activator in the sintering of spherical capacitive carbon in step 5.