Willow wood

Greenhouses, lumber mills, canneries, farmers, and manufacturers can reduce energy and disposal costs by using their waste as feedstock for energy systems. In Ireland, greenhouses for early tomatoes are heated with biomass from willow wood. The willow wood fuel costs one third as much as the oil it replaced. 

Table 2 Typical percentage composition of straw and hay compared to willow wood. 

In commercial diarcoal production, diarcoal yields of 0.33-0,41 kg/kg dry feed are possible (4). However, the residence times for the solids used in commercial charcoal productiwi, 12 18 hours (4), would result in a rather large and expensive pyrolysis reactor. Shortff residence times of the solids in the pyrolysis process are required to make the CASST process feasible. To determine whether the required diarcoal yields can be achieved at shorter residence times, pyrolysis experiments with willow wood have been performed. 

Charcoal yields and the volatile matter content of the charcoal produced decrease with increasing temperature (see figure 2). For willow wood the required diarcoal yield of 0.38 kg/kg dry feed can be obtained at a temperature of 350-400 C, giving a product with a volatile matter content of 30-50 wt,%. In this temperature range 46-60% (LHV-basis) of the energy content of the feedstock is retained in the charcoal. 

Willow wood, and char produced from willow wood, were used as feedstock. The proximate and ultimate analyses of both feedstocks are listed in table 4. The following types of experiments were carried out ... 

Typical amount of feed material was about 500 mg willow wood and 350 mg char. The particle size of the feed material used was less than 0.7 mm. As gasifying agent hydrogen, carbon dioxide, steam, or helium was used. 

The reactivity of char gasification was studied under three different atmospheres (hydrogen, carbon dioxide, and steam), at 800 C and two operating pressures (5 bar and 30 bar). The required char was prepared by pyrolysing willow wood in a tube kiln under nitrogen atmosphere at a temperature of 800 C, within a period of about 8 hours. The char was cooled down under inert conditions. 

Fig. 10 Weighi losing curve of char (prepared from willow wood) at 800 C, different atmospheres and pressures.

M. Kaiser Hydrogasification of willow wood in a pressurised thermobalance, DMT (Essen), July 1999. 

The U. S. National Energy Laboratory has used a genetically engineered Zymomonas mobilis to convert agricultural residues and sawdust to ethanol in a process that uses both the glucose and xylose. It is estimated that this will reduce the price of ethanol from 1.20/gal, to 0.70/gal.47 Recombinant E. coll converted willow wood to ethanol, which is estimated to cost 0.48/L.48 The market price in Sweden is 0.35/L. It is estimated that the price could be reduced 0.063/L. if the process started with waste and an-... 

Sugar beet Sweet sorghum Switch grass Willow Wood ... 

The fluid in these cadence-responsive knee units may be oil (hydraulic) or air (pneumatic). For hydraulic knees, the fluid is incompressible. The resistance to piston motion results from fluid flow through one or more orifices. As such, the resistance is dependent on the fluid viscosity and density, the size and smoothness of the channel, and the speed of movement. In contrast, for pneumatic knees, the fluid is compressible. The resistance is again due to fluid flow through the orifice(s) but is also influenced by fluid compression. Since air is a gas, potential leaks in pneumatic knee units will not result in soiled clothing, unlike what may occur with hydraulic knees. In addition, since air is less dense than oil, pneumatic units tend to be lighter than hydraulic units. However, since air is less dense and less viscous than oil, pneumatic units provide less cadence control than hydraulic units. Note that since viscosity is influenced by temperature, hydraulic (and pneumatic) knee units may perform differently inside and outside in cold weather climates. An example of a hydraulic cadence-responsive knee unit is the Black Max (USMC, Pasadena, Calif.). Additional examples include the Spectrum Ex (pneumatic, Hosmer, Campbell, Calif), Pendulum (pneumatic, Ohio Willow Wood, Mt. Sterling, Ohio), and Total Knee (hydraulic. Model 2000, Century XXII Innovations, Jackson, Mich.), which combine a cadence-responsive resistance swing-phase-control knee with a four-bar polycentric stance control knee. 

Huijgen WJJ, Smit AT, Reith JH, Uil Hd. (2011). Catalytic organosolv fractionation of willow wood and wheat straw as pretreatment for enzymatic cellulose hydrolysis. J Chem Technol Biotechnol, 86, 1428-1438. 

Constit. of willow wood (Salix viminalis). Cryst. + 3H2O. 

Figure 1. 600 MHz HNMR spectrum of hydrolyzed willow wood (Salix sp.) in...

Figure 5. HNMR spectrum of acid hydrolyzed willow wood. Peak at 6 ppm is...

Table I Lignin Content of Bark-Containing Willow Wood Chips (Lignin by TAPPI Method T-222 Original willow = 28.2 % lignin)...

Treatment of bark-containing willow wood chips with the fungus C. subvermispora for two weeks at 25-30°C resulted in a modest degree of delignification but a significantly higher level of water-soluble extractables compared to untreated controls. 

Wells Hinton Plastics Willow Wood Works London Road Amersham Bucks Amersham 7910... 

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