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

“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.
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)。

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