Pellet wood

Method Wood pellets Wood chips Fuel wood... 

In Austria the market for biofuels is established. Wood pellets, wood chips from forestry and sawmill residues have quite stable prices depending on supply and demand. The Price for pyrolysis oil is assumed to be the production cost calculated according (6). The price and the transport cost of the fuels used for the applications in this paper are listed in Table 3. The transport costs are calculated with a fixed and a variable con onent. The calculation is based on transportation by truck from the site of production to the site of use (storage of the biomass plant). 

Ltd., of Chandigarh, India, produces a recycled PE/PP/wood composite for use as a wood substitute, or as a filler in cast polyester for furniture. Natural Eiber Composites Inc., of Baraboo, WI, commercialized a pelletized wood fiber-filled plastic using recovered paper or wood fibers with PP, HDPE, or PS. " Mikron Industries manufactures a wood-plastic... 

GTI Gas Technology Institute Pilot US Lignocellulosics, pellets, wood chips Clean syngas Operational... 

While the rotary dryer shown is commonly used for grains and minerals, this system has been successfully applied to fluid-bed diying of plastic pellets, air-hft diying of wood fibers, and spray drying of milk solids. The air may be steam-heated as shown or heated By direct combustion of fuel, provided that a representative measurement of inlet air temperature can be made. If it cannot, then evaporative load can be inferred from a measurement of fuel flow, replacing AT in the set point calculation. 

FIG. 20-79 Effect of pelleting pressure on axial crushing strength of compacted calcite particles of different sizes demonstrating existence of a critical yield pressure. Inset shows the effect of hardness on critical yield pressure. [Benhow, Enlargement and Compaction of Particulate Solids, Stanley-Wood (ed.), Butteixooiihs, 169 (1.9S3),]... 

Activated carbon is an amorphous solid with a large internal surface area/pore strucmre that adsorbs molecules from both the liquid and gas phase [11]. It has been manufactured from a number of raw materials mcluding wood, coconut shell, and coal [11,12]. Specific processes have been developed to produce activated carbon in powdered, granular, and specially shaped (pellet) forms. The key to development of activated carbon products has been the selection of the manufacturing process, raw material, and an understanding of the basic adsorption process to tailor the product to a specific adsorption application. 

The plot in Fig. 13 shows the bleed emissions that were measured after a 24 hour soak. Two eanisters were tested, one loaded with a wood granular carbon with a mean particle diameter of 1.27 mm, the second with a wood pellet carbon with a mean particle diameter of 2.10 mm. Both carbon samples had equal BWC of 11.4 g/lOOml. Although both earbons had the same BWC, the larger pellet earbon had lower bleed emissions. These diffusion results are expected in light of Pick s Law. 

The current requirements have led to the development of pellet shaped activated carbon products specifically for automotive applications. These pellets are typically generated as chemically activated, wood-based carbons. 

Today, large amounts of biomass are already used to generate heat and electricity (mainly wood) and are predicted to increase further (e.g., wood-pellet-fuelled boilers, wood-chip-fuelled CHP plants, electricity generation from biogas). 

In contrast to the operation of vehicles, electricity and heat for stationary applications can be generated by the combustion of solid biomass without upstream biomass conversion to pure hydrogen (or methanol, BTL or DME). The efficiency of the direct use of solid biomass is generally higher. The overall efficiency of a solid-biomass-fuelled heat and power (CHP) plant is typically about 70% to 80% direct combustion of solid biomass (e.g., wood chips, wood pellets) in suitable boilers for heat generation only can reach an efficiency of more than 90%. 

More recently, about ten years ago, the first wood composite was marketed in pellets. 

The objectives of this project are consistent with the objectives (1) and (4) above. The general objective of this project has been to verify a new measurement method to analyse the thermochemical conversion of biofuels in the context of PBC, which is based on the three-step model mentioned above. The sought quantities of the method are the mass flow and stoichiometry of conversion gas, as well as air factors of conversion and combustion system. One of the specific aims of this project is to find a physical explanation why it is more difficult to obtain acceptable emissions from combustion of fuel wood than from for example wood pellets for the same conditions in a given PBC system. This project includes the following stages ... 

An experimental series showing the differences between fuel wood, wood pellets, and wood chips with respect to conversion behaviour as function of volume flux of primary air. 

Table 1 The mass balance of solid-fuel convertibles from conversion of wood pellets...

The method was tested with two wood fuels, namely wood pellets and fuel wood. The mass flow of conversion gas was measured at three levels of standard volume flows of primary air (50,100, and 150 m n/h). Double tests were carried out at each volume flow of air. The mass-balance result is presented in Table 1 and Table 2 above. 

Three standard wood fuels have been studied (a) wood chips, (b) wood pellets, and (c) fuel wood. Figure 17 displays the three types of wood fuels. The fuel wood is from softwood, namely pine and spruce. Table 3 shows the wood fuel data. The moisture, ash and elementary analysis is carried out by an accredited laboratory in Sweden according to Swedish test standards (SS). 

Figure 18 displays mass flux curves plotted against time. This particular selection of curves shows the difference in conversion gas rates with respect to wood fuel. Wood chips are significantly easier to convert than 6 mm wood pellets, which in turn have higher mass flux of conversion gas than fuel wood for a given volume flux of primary air through the conversion system. 

Figure 19 shows the stoichiometric coefficient y versus time. The y-coefficient is the molar ratio between the amount of hydrogen in the conversion gas and the amount of carbon in the conversion gas. In this particular selection of y-graphs the dynamic ranges for the different wood fuels during a batch are fuel wood 3 0, wood pellets 2.6 0, and wood chips 2.4 0. These dynamic ranges are quite representative of the whole range of volume fluxes tested. 

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