Method for hydrolyzing cellulose into sugar to produce spherical capacitive carbon

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.