Process Intensification for Cellulosic Biorefineries

Abstract

Utilization of renewable carbon source, especially non-food biomass is critical to address the climate change and future energy challenge. Current chemical and enzymatic processes for producing cellulosic sugars are multistep, and energy- and water-intensive. Techno-economic analysis (TEA) suggests that upstream lignocellulose processing is a major hurdle to the economic viability of the cellulosic biorefineries. Process intensification, which integrates processes and uses less water and energy, has the potential to overcome the aforementioned challenges. Here, we demonstrate a one-pot depolymerization and saccharification process of woody biomass, energy crops, and agricultural residues to produce soluble sugars with high yields. Lignin is separated as a solid for selective upgrading. Further integration of our upstream process with a reactive extraction step makes energy-efficient separation of sugars in the form of furans. TEA reveals that the process efficiency and integration enable, for the first time, economic production of feed streams that could profoundly improve process economics for downstream cellulosic bioproducts.

Kinetic Studies of Acid Hydrolysis of Food Waste-Derived Saccharides

“…Various hypotheses for the hydrolysis of inter-unit C-O linkages in linear saccharides have been reported [24][25][26][27][28][29][30][31] . saccharified crystalline cellulose 4,5,38 to soluble sugars with a very high yield (>90%) containing glucose as the major product (82%) at low temperature (85 °C) and short reaction time (30 min). It has been reported that AMSH becomes super-acidic via polarization of hydrogen of water in the hydration sphere of the cation and a synergy between the salt and added acid 4,35,39 , facilitating hydrolysis at faster rates with minimal degradation products (e.g.…”

“…Yan et al 41 achieved maximum glucose yields of 19% (34% selectivity) after 40 min of reaction at 160 o C using 1 wt.% (0.2 M) H2SO4. By comparison, the LiBr AMSH efficiently dissolved and saccharified cellulose in one step giving >90% yield of soluble sugars 5,38 (82% glucose selectivity) within 40 min at 85 o C. Sadula et al 5 reported a lower minimum price of HMF manufactured using LiBr AMSH compared to concentrated and dilute acid systems. This cost advantage 5 in HMF production using AMSHs is attributed to the single-stage conversion technology as well as the higher glucose yield (Table A.1).…”

“…Here k1 is the fast bond scission rate (min -1 per bond); k2 is the slow bond scission rate (min -1 per bond); kd is the glucose dehydration rate (min -1 ); cn is the initial saccharide concentration (mol/dm 3 shorter chain species, which ultimately get converted to glucose. Under strong acidic conditions 4,5,38 , glucose can further be dehydrated into HMF.…”

“…Cellulose and starch are natural polysaccharides consisting of glucose, which is a precursor for manufacturing some of the top-ten bio-based chemicals listed by the United States Department of Energy 3 . As a result, energy-efficient hydrolysis of polysaccharides to glucose has been investigated by several groups 1,[4][5][6][7][8][9][10][11][12] .…”

Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars

“…Potentially faster and more economical routes to saccharification of cellulosic biomass include pyrolysis, processing in molten salt hydrates, and solvent liquefaction, including acid hydrolysis, processing in ionic liquids and deep eutectic solvents. [17][18][19][20][21][22] These processes have demonstrated cellulosic sugar yields ranging from 50-96% although each has unique challenges. [23][24][25][26] Pyrolysis and processing in molten salt hydrates are accompanied by secondary reactions that degrade carbohydrates.…”