Replies to post #33289 on First American Scientific Corp. (fka FASC)

[TRCPA]

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2.0 ASTM TESTING

2.1 Biomass Drying, Milling and Mixing

Three 55-gallon drums of switch grass, three 55-gallon drums of corn stover, and three 55-gallon drums of saw dust (wood waste) were procured from the raw stock supplies at EERC. Each material was first dried and ground to nominally 15 wt% moisture and minus 1/4-inch particle size within EERC's on-site hammer mill.

Prior to shipment of these drums to First American Scientific Corp. (FASC, Vancouver, BC -- Canada) for 200 mesh grinding, EERC initially determined the nominal proximate and ultimate analyses of each biomass material per ASTM procedures ASTM D3176-89 and D5142-04 together with calorific value per ASTM D5865-07.

For each biomass material, FASC produced two 55-gallon drums of pulverized material using their patented Kinetic Disintegration System (KDS) mill -- see, e.g., Narayan and Kantonen (2009) and Kantonen et al. (2004). One drum contained a PSD that met the nominal 70 wt% thru 200 mesh PSD criteria above while the other drum contained material having a higher PSD. These two drums are designated as: (a) the -200 mesh drum, and (b) the +200 mesh drum. FASC then sent these drums of milled material back to EERC for subsequent analyses, storage, coal blending, and packaging in 1 to 5-gallon plastic lined containers for further shipment. Upon receipt, EERC analyzed each of the three biomass materials separately for: (1)

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true solids density per ASTM D2638-06 (Universal Oil Product Specification UOP851-84); (2) bulk density per ASTM D6683-01; (3) particle size distribution per ASTM D197-87, and (4) moisture content per ASTM D3173-03. These results are shown in Table 1.
In addition to the biomass, EERC also analyzed three coal feedstocks per the ASTM procedures in the above paragraph for subsequent blending with the milled biomass. These results are shown in Table 2 for the Illinois #6 (Ill#6) bituminous and Powder River Basin (PRB) sub-bituminous coals. Table 3 shows the results for the North Dakota Lignite (NDL).

During final milling of the biomass, FASC determined the specific power consumptions to achieve the nominal 200 mesh size. For the wood waste, the specific power consumption to produce either the -200 mesh or +200 mesh material was nominally 0.45 kW-hr/kg. For the corn stover and switch grass at either -200 mesh or +200 mesh, the specific power consumption was approximately 0.30 kW-hr/kg. These specific power consumptions were a significant improvement from those obtained by PWR during earlier 1970's peat milling at H. Gartenberg and Company (Chicago, IL) -- Sprouse and Rosemary (1980a) and Sprouse et al. (1980b). For these earlier biomass milling experiments, Gartenberg added dry ice to their conventional hammer mill process to produce a more brittle material for milling. It should be further noted here that the milling of pulverized coal to nominal 200 mesh size typically requires a specific power consumption of approximately 0.08 kW-hr/kg. Hence, the specific power consumption for biomass is about 4 to 5 times higher than for coal while also having a nominal calorific heating value that is approximately 30% lower.
Typical micrographs of the coal and biomass are shown in Figures 1 and 2. The coal particles, which are refractory, tend to be spherical in orientation (although quite ragged) while the biomass particles, which are fibrous, tend to be more cylindrical in orientation. This variance in shape tends to explain why pulverized biomass has much lower bulk densities than pulverized coal (Tables 1, 2 and 3). It also helps to explain why the internal friction angles for pulverized biomass are higher than for pulverized coal (as discussed in the next section) when also considering the fact that these cylindrical fibers can support tensile loads.

Finally, EERC prepared 27 coal/biomass blends from the three coals shown in Tables 2 and 3 and the three biomass feedstocks shown in Table 1. The first nine blends were made for coal/biomass mixtures at a 90/10 weight basis ratio. For each of these blends, +200 mesh biomass was selected. Next, another nine blends were produced for coal/biomass mixtures at a 50/50 mass ratio. For each of these blends, -200 mesh biomass was selected. The last nine blends were made for coal/biomass mixtures at a 75/25 mass ratio. Here, six of the blends used -200 mesh biomass, while the remaining three blends used +200 mesh biomass. Uniform mixing was achieved by rolling plastic lined drums of the pulverized raw stock material prior to mixing. After mixing, 1-gallon can samples were prepared from the mixed plastic lined drums following extensive rolling to ensure uniformity among the samples being shipped for subsequent bulk solids laboratory testing (see below).