New US Patent Issued for ‘Fast Hydrolysis’ Process for Biomass
According to USPTO Public PAIR, a U.S. patent #: 8268126 has been issued to Zhen Fang (Kunming, CN) and Chun Fang (WA, US) for technology that provides a simple and low-cost method to fast dissolve and hydrolyze lignocellulosic biomass with great potential for a novel biorefinery.
The patent entitled “Method, equipment and applications for fast complete dissolution and hydrolysis of lignocellulosic biomass” was issued on September 18, 2012 for work done by Professor Zhen Fang, Leader and Founder of Biomass Group at Chinese Academy of Sciences. Professor Fang stated, “We are very excited to have been granted this new U.S. patent containing such claims that provide protection for ‘fast hydrolysis’ process.
In previous work, Sasaki et al. [1] found that microcrystalline cellulose could be completely dissolved in water at temperature above 320 oC and became a ‘cellulose solution’, which made it possible to build up a continuous flow reactor for the rapid hydrolysis of cellulose. Continuous reaction of microcrystalline cellulose (20 wt%) in water at supercritical conditions (> 374 oC and 22.1 MPa) gave water-soluble products (with 100% conversion) containing 80% hydrolysates (glucose and oligomers) for short reaction time (ca. 0.05 s) [1]. However, the separating of pure cellulose from actual biomass (e.g., wood) is complicated and costly. It is difficult for the solubilization and hydrolysis of pure cellulose to be commercialized. Thus, it is necessary to find a method for complete dissolution of actual lignocellulosic biomass and for further refining to value-added products.
Fang et al. [2] found that by adding 0.8 wt% Na2CO3, actual wood without pretreatment can be completely dissolved upon fast-heating (7~16°C/s) to form a ‘wood solution’ at 329-367 oC at short reaction times (0.7-2 s). The ‘wood solution’ can be rapidly (ca. 15 s) hydrolyzed to sugars/sugar oligomers under homogeneous conditions.
Based on the above work, a ‘fast hydrolysis’ process was invented for actual lignocellulosic biomass:
(a) Placing lignocellulosic biomass (wood or grass particles) in 1.9~10 wt% alkaline solution, and keeping biomass/liquid ratio at (0.003~1.05)/1, as sample 1;
(b) Heating pure water to a temperature between 329~367 °C, as sample 2;
Mixing sample 1 with sample 2 from steps (a) and (b) in a reactor, keeping biomass concentration at 0.1~35.1%, adjusting pH of the mixture >11.4 and water density of 322~787 kg/m3, rapidly heating the mixture to 329~367°C (pressure of 14~106 MPa) at a heating rate of 7~16°C/s, and the lignocellulosic biomass will completely dissolve in 0.7~2 s to form ‘biomass solution’ that is further rapidly hydrolyzed in a homogeneous phase to sugars and sugar oligomers. In Fig. 1, an equipment was proposed for the continuous ‘fast hydrolysis’ process.
Fig. 1. Fast Hydrolysis of Biomass
The patent is the latest development in a 23-year effort by Professor Zhen Fang in the study of biomass hydrolysis process, aimed at a simple, fast and low-cost method for a novel biorefinery. ‘Fast hydrolysis’ process will be the technological key to economic utilization of abundant lignocellulosic biomass as viable feedstocks for the production of industrial sugar, ethanol and chemicals. His pioneering work opens the door, for the first time, to the possibility of developing industrial-scale technology at competitive cost for producing biofuels and value-added products from lignocellulosic biomass based on the ‘fast hydrolysis’ process in a flow reactor.
This patent is the ninth patent issued to Professor Fang adding to its portfolio of 3 pending international and 13 pending Chinese patent applications which cover various features of biorefinery technologies.
The newly issued patent is accessible on the USPTO’s website at http://portal.uspto.gov/external/portal/pair.
References
[1] Sasaki M, Fang Z, Fukushima Y, Adschiri T, Arai K. Dissolution and hydrolysis of cellulose in subcritical and supercritical water. Ind Eng Chem Res 2000; 39:2883-90.
[2] Fang Z, Fang C. Complete dissolution and hydrolysis of wood in hot water. AIChE J 2008; 54:2751-8.