| abstract |
The present invention is to provide a method for preparing concentrated aqueous solution of sugar, which uses biomass containing cellulose as raw material, said method comprises (1) a step of hydrolyzing biomass containing cellulose to prepare aqueous solution of sugar, (2) a step of filtering the aqueous solution of sugar obtained by the step(1) by precise filter membrane and/or ultrafilter membrane, and recovering the aqueous solution of sugar from the permeable side, and (3) a step of filtering the aqueous solution of sugar obtained by the step(2) by a reverse osmosis membrane, and recovering permeable water from the permeable side and concentrated aqueous solution of sugar from the non-permeable side. The method is characterized in that at least one part of the permeable water of said reverse osmosis membrane is utilized as water heating processing agent, biomass suspension, enzyme dilution, acid dilution, and/or base dilution. The present invention can provide a method for preparing concentrated aqueous solution of sugar in water saving type. The method comprises hydrolyzing biomass containing cellulose to prepare aqueous solution of sugar, removing biomass residue by using a precise filter membrane and/or an ultrafilter membrane, processing the solution by a reverse osmosis membrane, concentrating the aqueous solution of sugar, and enhancing the concentration of sugar, and recovering and re-utilizing the recovered water the permeable water wasted by the reverse osmosis membrane. |