Biomass co-firing trials on a down-fired utility boiler

Hammer mill operating and biomass physical conditions effects on particle size distribution of solid pulverized biofuels

“…High graphic geometric deviation (HS gm = d 84 /d 50 ) defines the dispersion related to the high-medium distribution region (coarse), as well as low graphic geometric deviation (LS gm = d 50 /d 16 ) for the medium-low region (fine). Predictive neural network surfaces (not shown) show similar behavior than S gm and ANOVA analysis established the same influences and repercussions of the input variables as well as multivariate analysis achieved also strong correlations (R 2 N 99%) between them.…”

“…The most widespread used is the geometric standard deviation (S gm ) (ISO 9276-2:2001), representing the dispersion between each particle size and the geometric mean size. S gm can be graphically divided into high graphic S gm (HS gm = d 84 / d 50 ) and low graphic S gm (LS gm = d 50 /d 16 ), corresponding to high-medium and medium-low fraction of the distribution, respectively. In addition, other dispersion parameters are used mostly regarding to ratios between the medium-high and low fractions of the distribution: mass relative span (MR s = (d 90 − d 10 ) / d 50 ), uniformity index (I u = d 95 / d 5 ), uniformity coefficient (C u = d 60 / d 10 ), and coefficient of gradation (C g = d 30 2 / (d 60 − d 10 )).…”

“…In combustion processes, the optimal size is established according to several criterions such as the residence time [14][15][16]; the thermodynamic conversion of the particle inside the combustion camera (e.g. Lu et al [17] showed a volatile yields decreasing with an increasing particle size and Sudhakar and Kolar [18] found the strongest influence of size on devolatilization time for wood particle); the flame stability (very fine particles, d p b 0.1 mm, plays a key role on the stability of the flame in pulverized wood burners [19,20]); and the chemical composition itself (Bridgeman et al [21] reported that the fine fractions have a significantly higher concentration of inorganic matter, moisture and nitrogen content but lower carbon content and calorific value than larger particles for switchgrass and reed canary).…”

A complete review based on various aspects of pulverized coal combustion

“…Gil et al reported low NO emission by addition of biomass. Steer et al also reported reduced NO x and increased CO emission during co‐firing in a 500 MW down‐fired boiler.…”

The effects of particle grinding on the burnout and surface chemistry of coals in a drop tube furnace

“…A drop tube furnace (DTF) was used to characterise the devolatilisation and burnout behaviour of the coal samples at 1100 °C in air for residence times between 35 ms to and 700 ms. The high heating rate and short residence times in the DTF environment closely resemble those experienced when coal is injected into the blast air of the blast furnace raceway making this a particularly relevant technique [23][24][25][26]. Particles were fed into the top at feed rates of 30 g/hr, entrained in a laminar air flow at 20 L/min and collected at the bottom by means of a cyclone collector.…”