Fuel short-rotation wood

Table IV, PROBABLE ENERGY REQUIREMENTS FOR A SHORT ROTATION WOOD FUEL CROP...

Tree crops however could be grown on much shorter rotations if the size and form of the crops were not limiting factors in the end use of the crop. Such is the case when the desired product is wood chips to be used for pulp, fuel, or feedstock for conversion to substitute fuels. Short-rotation tree farming... 

Most of the commercial tree plantations that produce wood for captive use as a raw material in manufacturing operations use a portion as fuel. Examples of short-rotation plantations are Hsted in Table 38 (127). Paper companies in the southeastern United States are reported to have short-rotation plantings also, eg, Weyerhaeuser, James River Corp., Buckeye Cellulose, and Lykes Brothers, but the intensity of maintenance is not known (127). 

Second-generation biofuel technologies make use of a much wider range of biomass feedstock (e.g., forest residues, biomass waste, wood, woodchips, grasses and short rotation crops, etc.) for the production of ethanol biofuels based on the fermentation of lignocellulosic material, while other routes include thermo-chemical processes such as biomass gasification followed by a transformation from gas to liquid (e.g., synthesis) to obtain synthetic fuels similar to diesel. The conversion processes for these routes have been available for decades, but none of them have yet reached a high scale commercial level. 

It was concluded from this detailed analysis of an IBPCS consisting of a short-rotation hardwood energy plantation, a wood chip-fueled power plant, a microalgal wastewater treatment pond, and an anaerobic digestion unit for SNG production that the effluents and by-products from one system component can be beneficially used by other components and lead to increased energy conversion efficiencies and energy recovery at lower costs. 

A further possibility for wood fuel production is for intensive short-rotation forestry when small trees might be harvested every five or ten years with a mobile mower/chipper laid out similarly to a grain combine. Such a machine might be expected to cover one acre per hour for a throughput of about 20... 

Tables 4-7 and 4-8 present bulk ash chemistries of various wood fuels obtained during test programs. Table 4-7 focuses upon virgin wood material, including sawdust and clean tree trimmings from the urban forest. Table 4-8 presents representative data from some urban wood wastes plus short rotation woody crops. Wide variations in ash compositions can be observed between the various woody fuel samples.

Nine hardwood species were investigated as fuelwood in short-rotation forestry with the astonishing result that the observed differences in the caloric values of woods were just 4 % (mean 20.0 kJ/g) and that only bark (with less importance as fuel due to its small contribution to biomass) showed larger variations of up to 13 % (mean 20.08 kJ/g) [56]. Highest energy contents were found in leaves (21.13 kJ/g ovendry). Thus, biomass yield and ecological tolerance will have more influence on the specific harvest than the caloric values. 

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