Of mixed hardwoods

Furthermore, water transport of mixed hardwood and softwood chips causes an increase in moisture level to 65% or greater, which so degrades the LHV of the biomass that it cannot be economical for any process, such as direct combustion, that produces water vapor from water contained in the biomass. The impact on straw is greater, in that moisture levels are so high that the LHV is negative. Pipeline transport of biomass water slurries can only be utilized when produced water is removed as a liquid, such as from supercritical water gasification. 

Finally, oil transport of mixed hardwood and softwood chips gives a fuel that is more than 30% oil by mass and is two-thirds oil and one-third wood on a thermal basis. 

Schultz, T. R, Blermann, C. J., and McGinnis, G. D., Steam explosion of mixed hardwood chips as a biomass pretreatment. Industrial Engineering Chem Product Res Dev 1983, 22 (2), 344-348. 

Now, if the sawdust of mixed hardwood is assumed to be in fact the sawdust of Western red cedar, the Tc for a sawdust heap of mixed hardwood, formed into a sphere, 82 cm in diameter, and placed in the atmosphere under isothermal conditions, which is cited in Table 21, is calculated at 134.8 °C, because the values of the variables, a, b, r, and apart from the constant, A T, in Eq. (79), are fixed for the sphere at 12574.6, -25.1238, 41, 0.16 and 3.32, respectively. The value of 7). thus calculated is in fair agreement with the value of 135 °C measured actually by Anthony et al. for the sphere [68]. Similarly, if the sawdust of Kiefemholz (German pine) is assumed to be in fact the sawdust of Douglas fir, the for a sawdust heap of Kiefemholz, formed into a sphere, 100 cm in diameter, and placed in the atmosphere under isothermal conditions, which is also cited in Table 21, is calculated at 131.8 °C, because the values of the variables, a, b, r, and apart from the constant, A T, in Eq. (79), are fixed for the sphere at 12489.87, -24.6042, 50, 0.14 and 3.32, respectively. The value of Tc thus calculated is in fair agreement with the value of 130 °C measured actually by John for the sphere [69, 70]. Once again, if the sawdust of Kiefemholz is assumed to be in fact the sawdust of Douglas fir, the Tc for a sawdust heap of Kiefemholz, formed into an infinite slab, 40 cm in thickness, and placed in the atmosphere under isothermal conditions, which is also cited in Table 21, is calculated at 139.0 °C, because the values of the variables, a, b, r, dfc and dc, apart from the constant, A T, in Eq. (79), are fixed for the infinite slab at 12489.87, -24.6042, 20, 0.14 and 0.878, respectively. The value of 7) thus calculated is in fair agreement with the value of 140 °C measured actually by John for the slab [69]. 

Variations found in CTO composition result primarily from the species of wood pulped and the location and climate where the trees are grown. Pulping process variations further affect CTO composition. The best CTO is produced from pine wood. However, many U.S. mills mix hardwood with pine to reduce fiber costs, or mix hardwood black Hquor with pine black Hquor. This lowers the rosin content. The composition of CTO produced in the southeastern United States and of typical Canadian and Scandinavian CTOs are shown in Table 2. 

Bowden, R. D., K. J. Nadelhoffer, R. D. Boone, J. M. Melillo, and J. B. Garrison. 1993. Contributions of aboveground litter, belowground litter, and root respiration to total soil respiration in a temperate mixed hardwood forest. Canadian Journal of Forest Research 23 1402-1407. 

Monk, C. D. 1965. Southern mixed hardwood forests of northcentral Florida. Ecol. Monogr. 35 335-354. 

The cost of transporting wood chips by truck and by pipeline as a water slurry was determined. In a practical application of field delivery by truck of biomass to a pipeline inlet, the pipeline will only be economical at large capacity (>0.5 million dry t/yr for a one-way pipeline, and >1.25 million dry t/yr for a two-way pipeline that returns the carrier fluid to the pipeline inlet), and at medium to long distances (>75 km [one-way] and >470 km [two-way] at a capacity of 2 million dry t/yr). Mixed hardwood and softwood chips in western Canada rise in moisture level from about 50% to 67% when transported in water the loss in lower heating value (LHV) would preclude the use of water slurry pipelines for direct combustion applications. The same chips, when transported in a heavy gas oil, take up as much as 50% oil by weight and result in a fuel that is >30% oil on mass basis and is about two-thirds oil on a thermal basis. Uptake of water by straw during slurry transport is so extreme that it has effectively no LHV. Pipeline-delivered biomass could be used in processes that do not produce contained water as a vapor, such as supercritical water gasification. 

Figure 2D compares a number of sulfite pulps. Two of them, an unbleached spruce sulfite, USS, and an unbleached mixed hardwood sulfite, HS, have remarkably similar degradation curves but show different final residues. A bleached neutral sulfite semichemical pulp, FB, and an unbleached semichemical birch sulfite, SBS, have similar and much steeper initial degradation curves than the other two pulps. The semichemical birch sulfite pulp, SBS, has a degradation curve which crosses over those of the other three pulps shown in Figure 2D. 

Like other pyrolysis oil processes. Biocarbons Corporation s reactor produces a large number of oil compounds. For mixed hardwood (maple, birch and beech) pyrolyzed at typical operating conditions, 69 peaks were found by GC/MS analysis. Of these, the 14 peaks present at above 2 mole percent, represented 45 mole percent of the product that came through the GC. The 27 peaks between 1 and 2 mole percent, represented an additional 37 mole percent of the product. These compounds that were identified are listed in Table 1, in order of appearance (time). Several of the 4-position groups could also be occurring at the 3 position. All are reactable to make a phenol-forma Idehvde type adhesive. Pyrolysis oil from pine that was nude at the same operating condition (but has not yet been tested for adhesive use) had essentially the same compounds present at >1 mole percent, but at different relative concentrations. Some lower concentration compounds such as fatty acids are only produced from pine, but these compounds are specific to softwoods and the composition of softwoods. A comparison between the mixed hardwoods and pine products is shown in Table 2. 

T2% of Area) GC/MS Compound Peaks Identified In 11/99 Mixed Hardwood Oils. 

Techniques such as Py-MS or Py-GC/MS are not always suitable for the identification of less volatile or highly polar compounds. HPLC analysis with MS detection provides a better tool in such cases, and it was successfully applied for lignin pyrolysate analysis (see Section 5.7). Pyrolysis products from a lignin sample from mixed hardwood, obtained using the organosolv procedure with ethanol/water and generated at 510° C in an on-line Curie point pyrolyser and analyzed by HPLC [8], indicated the presence of a series of compounds shown in Table 9.1.7. 

Out in Six Different Laboratories. Tbe Total Yield in Vanillin Syringaldebyde S is Expressed in pmoles/g of Lignin Milled Wood Lignin Steam Explosion Organosolv Lignin from from Cotton Wood Lignin from Aspen Mixed Hardwood V and Kraft Lignin from Mixed Softwood... 

Effect Of Binder Level On Mixed Hardwood Flakeboard Properties... 

Figure 7. Modulus of rupture vs. Mondur MR level for mixed hardwood flake-...

We wish to thank Dr. Darrell D. Nicholas, Mr. Roy D. Adams and Ms. Susan Mateer of the Institute of Wood Research at Michigan Technological University for their work in conducting the mixed hardwood flakeboard experimental program. We also wish to thank Dr. Michael 0. Hunt of Purdue University and Dr. William F. Lehmann of Weyerhaeuser Corporation for their help in the red oak flake-board work and Mr. Otto G. Udvardy of Borden Chemical for the aspen waferboard study. Finally, we would like to thank Dr. Ronald Taylor of Mobay Chemical Corporation for his considerable advice and help with the multiple correlation analysis. 

DeBusk, W. F. and K. R. Reddy. 1987. Removal of floodwater nitrogen in a cypress-mixed hardwood swamp receiving primary sewage effluent. Hydrobiologia 153 79-86. 

If the stock is highly refined then a higher proportion of fines are present. The surface area of fines is much greater than that of fibre, typically 6-8 mVg for a mixed hardwood/softwood blend, compared to 1-1.5 mVg for fibres. Obviously the size demand, to cover the surface of the fines, is going to be much greater. 

Grethlein HE, Allen DC, Converse AO. (2004). A comparative study of the enzymatic hydrolysis of acid-pretreated white pine and mixed hardwood. Biotechnol Bioeng, 26,1498-1505. 

Yoon S-H,Tunc MS, ran Heiningen A. Near-neutral pre-extraction of hemiceUuloses and subsequent kraft pulping of southern mixed hardwoods. Tappi J 2011 10(1) 7—15. 

Tunc MS, van Heiningen ARP. HemiceUulose extraction of mixed southern hardwood with water at 150 °C effect of time. Ind Eng Chem Res 2008 47 7031-7. 

Tunc MS, van Heiningen ARP. Characterization and molecular weight distribution of carbohydrates isolated from the autohydrolysis extract of mixed southern hardwoods. Carbohydr Polym 2011 83(1) 8-13. Martin-Sampedro R, Eugenio ME, Moreno JA, ReviUa E,ViIlar JC. Integration of a kraft pulping miU into a forest biorefinery pre-extraction of hemiceUulose by steam explosion versus steam treatment. Biores Technol 2014 153 236-44. 

Moens L, Black SK, Myers MD, Czernik S. Study of the neutralization and stabilization of a mixed hardwood bio-od. Energy Fuels 2009 23 2695-9. 

Karl T, Guenther A, Spirig C, Hansel A, Fall R (2004) Seasonal variation of biogenic VOC emissions above a mixed hardwood forest in northern Michigan. Geophys Res Lett 30 2186... 

---