Wood char

Documented efforts at cokemaking date from 1584 (34), and have seen various adaptations of conventional wood-charring methods to the production of coke including the eventual evolution of the beehive oven, which by the mid-nineteenth century had become the most common vessel for the coking of coal (2). The heat for the process was suppHed by burning the volatile matter released from the coal and, consequently, the carbonization would progress from the top of the bed to the base of the bed and the coke was retrieved from the side of the oven at process completion. 

Public nuisance from settled wood char indicates collectors are needed. 

Samuel P. Hays. From Conservation to Environment Environmental Politics in the United States since World War II. In Out of the Woods. Char Miller and Hal Rothman, eds. Pittsburgh, PA University of Pittsburgh Press, 1997, pp. 101-126. Source for Earth Day. 

The pyrolysis of wood, oxygen chemisorption and oxidation of wood chars were carried out in a computerized coupled TG-FTIR system containing Cahn-R-100 electric balance, DuPont Model 990 thermal analyzer and Nicolet MX-1 Fourier transform infrared spectrometer. All of these sequential processes are carried out within the thermal balance without interruption. 

Figure 1 has shown that the maximum chemisorption of oxygen on chars from untreated wood occurs at HTT 450°-500°C. However, in order to understand better the effect of metal ions on the total process consisting of pyrolysis and subsequent chemisorption and oxidation of wood char, it was necessary to carry out pyrolysis, isothermal chemisorption and oxidation reactions in a single experiment. A typical overall pyrolysis, isothermal chemisorption (140°C) and oxidation curve is shown in Figure 2. The temperature program is (1) heat from 25° to 500°C at 5°C/min, (2) cool at...

Dasappa, S., Paul, P. J., Mukunda, H. S., and Shrinivasa, U., Wood-Char Gasification Experiments and Analysis on Single Particles and Packed Beds, 27th International Symposium on Combustion, The Combustion Institute, 1998, pp 1335-1342. 

Boroson, M.L., Howard, J.B., Longwell, J.P., Peters, W.A., Heterogeneous cracking of wood pyrolysis tars over fresh wood char surfaces, Energy Fuels, 1989, 3, 735. 

Dasappa S., Paul P.J., Mukunda H.S., and Shrinivasa U., The Gasification of Wood-Char Spheres in CO2-N2 Mixtures Analysis and Experiments ,... 

Due to this technology s stage of development, no cost information is available regarding product cost. Cost information regarding production cost, however, has been developed. The cost of producing BAC is 39% less than producing conventional activated carbon 227.00 per ton for BioBinder pellets compared with 375.00 per ton for activated carbon pellets made from wood char and wood tar in 1996 dollars (D137421, p. 2). 

Nguyen,T. H., Brown, R. A., and Ball, W. P. (2004). An evaluation of thermal resistance as a measure of black carbon content in diesel soot, wood char, and sediment. Org. Geochem. 35(3), 217-234. 

In wood charring studies by Schaffer at the Forest Products Laboratory (FPL) (31), 3-inch-thick pieces of wood were vertically... 

The FDS5 pyrolysis model is used here to qualitatively illustrate the complexity associated with material property estimation. Each condensed-phase species (i.e., virgin wood, char, ash, etc.) must be characterized in terms of its bulk density, thermal properties (thermal conductivity and specific heat capacity, both of which are usually temperature-dependent), emissivity, and in-depth radiation absorption coefficient. Similarly, each condensed-phase reaction must be quantified through specification of its kinetic triplet (preexponential factor, activation energy, reaction order), heat of reaction, and the reactant/product species. For a simple charring material with temperature-invariant thermal properties that degrades by a single-step first order reaction, this amounts to -11 parameters that must be specified (two kinetic parameters, one heat of reaction, two thermal conductivities, two specific heat capacities, two emissivities, and two in-depth radiation absorption coefficients). 

These results show that the proposed technique provides a fast and reliable method for the solution of stiff ODE models of reacting polydispersed particles. Recently, Turton (9) applied this method successfully to the modeling of wood char combustion in a transport reactor. 

Turton, R., "Combustion of Wood Char in a Transport Reactor," M.S. Thesis, Dept, of Chemical Engineering, Oregon State University, Corvallis, OR, 1979. 

From a theoretical perspective, pure cellulose contains 44.4 wt % carbon, so the maximum theoretical yield of charcoal, assuming all of the cellulosics can be carbonized, is 44.4 wt %. But with dry wood chars containing about 60 to 70 wt % fixed carbon (c/. Table 8.6), the theoretical maximum yields of charcoal including volatile matter and ash from wood feedstocks then correspond to about 65 to 75% by weight of the dry wood. It is evident that if... 

Steam gasification of wood char and the effect of hydrogen inhihition on the chemical kinetics... 

Stoltze et al. find that the gasification of hardwood is 2-3 times slower than straw, probably due to the different char structure and composition. However, since the density of the hardwood char is 5 times higher than the one of straw, in a volume basis the reactivity of wood char is double than of straw. The direct consequence of this fact is that the gasifiers for wood char only require half the volume of a straw gasifier. 

Capart, R. Gelus, M. (1988). A volumetric mathematical model for steam gasification of wood char at atmospheric pressure, Energy from Biomass 4. Proceedings of the 3rd comractors meeting, Paestum, 25-27 May, pp. 580-583. 

The inhibition effect of CO is widely accepted and reasonably well documented for coal char gasification but not for biomass. The lack of extensive literature for wood char CO2 gasification kinetics including CO has strongly motivated this investigation. 

Barrio, M., Gpbel, B, Risnes, H., Henriksen, U., Hustad, J.E. Sprensen, L.H, Steam gasification of wood char and the effect of hydrogen inhibition on the chemical kinetics. This conference. 

The area of the untreated charcoal after wood pyrolysis at 600°C is somewhat lower than the CO2 areas reported in the literature which, for different wood chars, range between 430 and 520 m /g. One may also note that the surface area value changes with the heat treatment temperature and passes through a maximum for pyrolysis ten ratures around 800°C. Tlus trend is explained in the literature. ... 

Boroson ML, Howard JB, Longwell JP, Peters WA, "Heterogeneous Cracking of Wood Pyrolysis Tars over Fresh Wood Char Surfaces , Energy Fuels, 3, 735-740, 1989. 

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