Adriaan van Heiningen

SO2-Ethanol-Water (SEW) Pulping: II. Kinetics for Spruce, Beech, and Wheat Straw

Abstract SO2-ethanol-water (SEW) delignification kinetics for spruce, beech, and wheat straw are presented. All these species produce pulps using SEW cooking liquor and follow first order delignification kinetics at similar bulk delignification rates. However, residual delignification is much slower for beech than for spruce. The hemicelluloses retention (135°C) and cellulose degradation kinetics are also characterized for beech SEW pulping. Xylan and glucomannan are removed from the pulp following first-order kinetics with a higher rate constant for xylan. Cellulose is retained in the fibers until kappa number 9, after which it starts to dissolve in the liquor. The yield also drops significantly in the region of kappa numbers 9–7. Cellulose degradation is followed by intrinsic viscosity measurements and is found to be zero order in cellulose. The rates are higher at 135 and 145°C for beech SEW pulping than for spruce.

SO2-Ethanol-Water (SEW) Pulping: I. Lignin Determination in Pulps and Liquors

Abstract Quantitative determination of lignin in SO2-ethanol-water (SEW) pulps and spent liquors is described. The methods developed for conventional sulfite pulping are successfully applied to the SEW process. Linear correlations between Klason/total lignin content and kappa number are found over a wide pulp yield range for spruce, beech, and wheat straw. Lignin content of the spruce spent SEW liquors is determined using either hydrogen peroxide to remove SO2 and dilution by 3% sulfuric acid or simply by dilution with 0.1M sodium hydroxide. The recommended wavelength is 280 nm. The experimentally found values for the extinction coefficient of dissolved lignin in 3% sulfuric acid and in 0.1M NaOH are 19 and 23 L/(g·cm), respectively. The interference of furanic compounds is eliminated by reduction with sodium borohydride.

American Process: Production of Low Cost Nanocellulose for Renewable, Advanced Materials Applications

Nanocellulose has proven to be a versatile material with a vast array of potential commercial applications including composites and foams for automotive , aerospace , and building construction , viscosity modifiers for cosmetics and oil drilling fluids , and high performance fillers for paper , packaging , paints , plastics , and cement . In addition to material performance properties like gelation, shear thinning, exceptionally high strength , and light weight , nanocellulose has a strong sustainability profile. Being made from biomass , it is renewable , biodegradable , compostable , and designed for the environment with a sustainable life cycle carbon footprint. American Process Inc.’s (API’s) American Value Added Pulping (AVAP)® technology offers commercial-scale production of nanocellulose with flexibility in final product morphology (rod shaped nanocrystals and fiber shaped nanofibrils) and surface properties (hydrophilic or hydrophobic) to service the wide variety of emerging end-use market segments. The novel hydrophobic lignin -coated variety of AVAP nanocellulose can be incorporated into plastics. This achievement overcomes a well-known barrier to commercial utilization of nanocellulose. AVAP nanocellulose will also be low cost, with commercial selling prices anticipated to be comparable to competing petroleum-based polymers.

The effect of bark on sulfur dioxide-ethanol-water fractionation and enzymatic hydrolysis of forest biomass

The focus of this study was to find out the effect of bark on SO2-ethanol-water (SEW) fractionation and enzymatic hydrolysis of forest biomass. Softwood bark was found to be more harmful than hardwood bark in both processes. For softwood, the amount of undigested wood in SEW fractionation increased with the increasing bark content, whereas the hardwood bark did not impair the fractionation of wood. The higher the softwood bark content was the lower were the yields in enzymatic hydrolysis likely due to the unproductive binding of enzymes on lignin and other compounds. Addition of surfactant Tween 20 (2% w/w on substrate) prior to enzyme more than doubled the sugar yield of bark-rich softwood pulp. Hardwood bark impaired enzymatic hydrolysis when its share was over 28%. According to a preliminary study, lignosulfonates from the carry-over liquor seem to improve the sugar yield in the enzymatic hydrolysis by acting as a surfactant.