“Fast dissolution of cellulose for hydrolysis” was authorized US patent
Recently, “fast dissolution of cellulose for hydrolysis” invented by Prof. Zhen Fang was authorized US patent (US patent#: 9115215; issue date: 08/25/2015).
In the nature, lignocellulosic biomass, such as wood and grass, is roughly consisted of 50% cellulose, 25% hemicellulose, and 20% lignin. Cellulose can be hydrolyzed into saccharides which are further used for producing cellulosic ethanol through fermentation. Because lignocellulosic biomass is water-insoluble, the current industrial methods for hydrolyzing biomass proceed mainly in a semi-continuous percolating reactor containing 0.4～0.8% dilute aqueous sulphuric acid, at temperature of 180～190℃ and under pressure of 12～14 atmospheres. Reports about continuous production of sugars in a high-pressure continuous flow reactor were not found.
Prof. Fang invented a method for completely dissolving and rapidly hydrolyzing cellulose, and uses thereof.
- Cellulose is placed in an acidic aqueous solution with a [H+] concentration of 10-7～1 M or an alkaline aqueous solution with a [OH–] concentration of 10-7～1 M as sample A, wherein the volume ratio of solid to liquid is (0.003～05).
- The acidic aqueous solution with a [H+] concentration of 10-7～1M or the alkaline aqueous solution with a [OH–] concentration of 10-7～1M is heated up to 261～352℃ as sample B.
- Sampe A and sample B obtained from step 1 and step 2 are mixed in a reactor to a concentration of cellulose of 0.1%～35%, the concentration of the mixed solution is adjusted to an acidity of 10-7～1M [H+] or an alkalinity of 10-7～1M [OH–], and a water density of 587～997 kg/m3, pressure is set at 6～584 MPa. The mixture is rapidly heated up to 261～352℃ at heating rate of 7.8～8℃/s, and then cellulose is dissolved completely in 0.8～2 sec and hydrolyzed in 5 sec.
Using this technique, it is the first time for achieving complete dissolution and rapid hydrolysis of cellulose at a lower temperature, which not only dramatically reduces the cost of hydrolysis but also improves the safety of production and extends the service life of equipment in a flow system, thus possessing a good application prospect.
1、将纤维素置于浓度为10-7～1M [H+]酸性或10-7～1M [OH–]碱性水溶液中，固液体积比为(0.003～1.05)：1；
3、混合步骤1和2所得物置于反应器中，纤维素浓度为0.1%～35%，调节混合后的物料溶液浓度为10-7～1M [H+]酸性或10-7～1M [OH–]碱性，水密度为587～997 kg/m3，设定压力为6～584 MPa，加热速率为7.8～14.8℃/s，快速加热至261～352℃，0.8～2秒即能完全溶解纤维素。
该发明获美国专利(US patent#: 9115215; issue date: 08/25/2015)。