“Fast dissolution of cellulose for hydrolysis” was authorized US patent

Recently, “fast dissolution of cellulose for hydrolysis” invented byProf. Zhen Fangwas 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. Fanginvented 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^-7～1Mor an alkaline aqueous solution with a [OH^–] concentration of 10^-7～1Mas sample A, wherein the volume ratio of solid to liquid is (0.003～05).

• The acidic aqueous solution with a [H⁺] concentration of 10^-7～1Mor the alkaline aqueous solution with a [OH^–] concentration of 10^-7～1Mis 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.

一种完全溶解和快速水解纤维素的方法及其应用获美国专利

自然界中的木质纤维素生物质如木材和草类，大约是由50%的纤维素，25%的半纤维素和20%的木质素组成。纤维素经水解能够降解为糖类，进而用于发酵生产纤维素酒精。由于木质纤维素生物质不溶于水，现有的工业化生物质水解方法主要是以半连续式渗透反应器、在180～190℃和12～14 大气压下的0.4～0.8%稀硫酸水溶液中水解。未见使用高压连续反应器进行连续生产的报道。

方真研究员在深入研究后发现，在溶解和快速水解纤维素之前，先将其置于酸性或碱性溶液中，然后再将得到的混合物与高温稀酸或稀碱溶液混合，并以一定的加热速率加热至一定的温度，则可以实现纤维素的完全溶解和快速水解。在此基础上，发明人提出如下技术方案：

一种完全溶解和快速水解纤维素的方法，包括以下步骤：

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；

2、将10^-7～1M[H⁺]酸性或10^-7～1M[OH^–]碱性水溶液加热至261～352℃；

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。

溶剂化的纤维素可以很方便地应用于低温的高压流动式的反应器，进一步降低了生产成本，连续水解生产糖类及别的生物燃料和产品。

该发明获美国专利(US patent#: 9115215; issue date: 08/25/2015)。