Hydrolysis of cellulose in supercritical water: reagent concentration as a selectivity factor
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In this work, the influence of reagent concentration on hydrolysis reactions of cellulose in supercritical water was analyzed. The hydrolysis was carried out at 400 °C and 25 MPa with reaction times between 0.07 and 1.57 s and feeding cellulose concentrations between 5 and 20 % w/w (1.5–6 % w/w at reactor inlet). Also, a flash separator was used to separate vapor in the product stream in order to increase the final concentration. The best result for sugar production (79 % w/w) was obtained working with a cellulose concentration of 5 % w/w and 0.07-s reaction time. For glycolaldehyde production, the best result (42 % w/w) was obtained with a concentration of 20 % w/w and 1.57 s. The employment of a flash separator allowed reducing the water content by 50 %. It was also observed that by increasing the cellulose concentration in the reactor up to 4 % w/w, the hydrolysis took place with a similar kinetic as that in the heterogeneous media, thus reducing the conversion rate of cellulose in supercritical water.
KeywordsBiomass Glycolaldehyde Kinetics Sugars Supercritical fluids
The authors thank the Spanish Ministry of Economy and Competitiveness for Project CTQ2011-23293, CTQ2011-27347, CQT2013-44143-R and ENE2012-33613. MDB thanks the Spanish Ministry of Economy and Competitiveness for Ramón y Cajal research fellowship RYC-2013-13976.
Conflict of interest
The authors declare that they have no conflict of interest.
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