QUALITY CHANGES, DUST GENERATION, AND COMMINGLING ...

More documents

Recommendations

Info

However, data on the PSD of dust generated during grain handling in a bucket-elevator system and the fraction that might be health hazards are limited (Wallace, 2000). Published studies either did not consider the PSD (Martin and Sauer, 1976) or were limited to dust
have increased the demand for IP containerization (Prentice, 1998). A third approach is to segregate or handle the IP grain in non-dedicated facilities. Due to limited scientific data on grain commingling in normal handling operations, it is not currently possible to predict the level of purity that could be achieved with the third, less expensive approach. In addition to unintentional and natural threats to grain purity, intentional introduction of contaminants is also possible. The Strategic Partnership Program Agroterrorism (SPPA) Initiative, a joint effort of various federal agencies to help secure the nation’s food supply, listed corn farms, grain elevator and storage facilities, grain export facilities, rice mills, and soybean farms as five of the 14 pre- and post-harvest sites that are critical nodes for assessment because of vulnerability to terrorist attack with biological weapons (US FDA, 2006). As with unintentional commingling, current lack of data on commingling during grain handling makes it difficult to predict the levels of intentionally introduced contaminants that would propagate through the grain handling system. Because full-scale tests of contaminant mixing in the grain handling system are unrealistic, the inability to make useful predictions seriously hampers any efforts to conduct a scientific study of the fate of contaminants introduced into the system. Obtaining sufficient field data would require numerous resource-intensive experiments in grain elevators. A validated mechanistic model for predicting grain commingling in various types of elevator equipment will be valuable for extending the knowledge of grain commingling beyond the few current experimental studies. Continuum models, kinetic theory-based models, and discrete element models (DEM) (Wightman et al., 1998) have potential to simulate grain commingling in elevators. Due to the need to track individual particles, DEM is a proven way to simulate discrete objects like grain kernels and to predict the movement and commingling of grains in bucket-elevator equipment. DEM is an explicit numerical scheme in which particle interaction is monitored contact by contact, and the particle motion is modeled particle by particle. First introduced by Cundall (1971) and Cundall and Strack (1979) to model soil and rock mechanics, this method has been successfully applied to modeling of similar processes such as particle mixing in a rotating cylinder (Wightman et al., 1998); three-dimensional, horizontal- and vertical-type screw conveyors (Shimizu and Cundall, 2001); and filling and discharge of a plane rectangular silo (Masson and Martinez, 2000). 5
Page 1 and 2: QUALITY CHANGES, DUST GENERATION, A
Page 3 and 4: soybean during handling with a comm
Page 5 and 6: Copyright JOSEPHINE MINA BOAC 2010
Page 7 and 8: soybean during handling with a comm
Page 9 and 10: 2.2.7 Grain Commingling ...........
Page 11 and 12: CHAPTER 5 - Material and Interactio
Page 13 and 14: List of Figures Figure 2.1 Identity
Page 15 and 16: Figure A.1 Mean cumulative and mean
Page 17 and 18: Table 5.5 Experimental data for sta
Page 19 and 20: Table A.39 Percentage of particulat
Page 21 and 22: Table A.81 Coefficient of restituti
Page 23 and 24: List of Symbols Ci Instantaneous co
Page 25 and 26: P Conditional probability of the ra
Page 27 and 28: σr σo τi τij ωb ωn ω0 Standa
Page 29 and 30: To Mrs. Maxine Jevons and all my co
Page 31 and 32: 1.1 Background CHAPTER 1 - INTRODUC
Page 33: al., 1990). Repeated handling data
Page 37 and 38: (3) develop and evaluate particle m
Page 39 and 40: Cupp, O. S., D. E. Walker, and J. H
Page 41 and 42: NIOSH. 1983. Occupational Safety in
Page 43 and 44: CHAPTER 2 - REVIEW OF LITERATURE 2.
Page 45 and 46: Amornthewaphat et al. (1999) found
Page 47 and 48: EPA, 2007). PM-2.5, PM-4, and PM-10
Page 49 and 50: (geometric standard deviation) of c
Page 51 and 52: demand for safer identity-preserved
Page 53 and 54: 2.2.3 Identity Preservation, Segreg
Page 55 and 56: labeling regulations. On the other
Page 57 and 58: USDA ERS (2001) enumerated several
Page 59 and 60: Machinery Floor #8 Scale Floor #7 C
Page 61 and 62: (first-in, first-out) queue service
Page 63 and 64: experiment. Data suggested that con
Page 65 and 66: compositions, properties, or temper
Page 67 and 68: 2.2.8.2.2 Degree of Mixedness Weide
Page 69 and 70: 1 ∑ 1 − n i= ( x − x) 2 s s =
Page 71 and 72: of groups or clusters of adjacent p
Page 73 and 74: problems in engineering and applied
Page 75 and 76: al., 1992; Di Renzo and Di Maio, 20
Page 77 and 78: the non-linear contact model (e.g.,
Page 79 and 80: Wightman et al. (1998) applied DEM
Page 81 and 82: (G) for an elastic, homogenous, and
Page 83 and 84: contacts, and this couple resists p
Page 85 and 86:
angle of friction and is independen
Page 87 and 88:
2.2.11 Summary Customers around the
Page 89 and 90:
Bardet, J. P., and Q. Huang. 1993.
Page 91 and 92:
Carter, C. A., and G. P. Gruere. 20
Page 93 and 94:
Falck-Zepeda, J. B., G. Traxler, an
Page 95 and 96:
Hanna, H. M., D. H. Jarboe, and G.
Page 97 and 98:
James, C. 2004. Global status of co
Page 99 and 100:
Li, Y., Y. Xu, and C. Thornton. 200
Page 101 and 102:
Mustoe, G. G. W., and M. Miyata. 20
Page 103 and 104:
Roseman, B., and M. B. Donald. 1962
Page 105 and 106:
Taylor, M. R., and J. S. Tick. 2001
Page 107 and 108:
Vu-Quoc, L., X. Zhang, and O. R. Wa
Page 109 and 110:
CHAPTER 3 - Feed Pellet and Corn Du
Page 111 and 112:
commercial handling study caused 4.
Page 113 and 114:
separators was 5.0 m 3 ·s -1 and t
Page 115 and 116:
Standard S269.4 (ASAE Standards, 20
Page 117 and 118:
3.3 Results and Discussion 3.3.1 Pa
Page 119 and 120:
Zatari et al. (1990) indicated that
Page 121 and 122:
Table 3.3 Mean total collected dust
Page 123 and 124:
ASTM Standards. 2000. E300-92: Stan
Page 125 and 126:
CHAPTER 4 - Size Distribution and R
Page 127 and 128:
fills the gap where no complete PSD
Page 129 and 130:
4 3 4 1 5 6 7 2 B 8 - Dust sample c
Page 131 and 132:
mm diameter sampling probe, a 0.20-
Page 133 and 134:
4.2.5 Data Analysis The four wheat
Page 135 and 136:
Table 4.4 Mean dust mass flow rates
Page 137 and 138:
different. The sampling methods wer
Page 139 and 140:
4.3.2.2 Shelled Corn - Effect of Re
Page 141 and 142:
The percentage of PM-2.5 from the u
Page 143 and 144:
4.5 References ACGIH. 1997. 1997 Th
Page 145 and 146:
Pearson, T., J. D. Wilson, J. Gwirt
Page 147 and 148:
true physics with a manageable numb
Page 149 and 150:
119 Grain/ Oilseed Kernels Paramete
Page 151 and 152:
5.2.2 Particle Density Particle den
Page 153 and 154:
their simulations. The authors foun
Page 155 and 156:
125 Particle Length (mm), l Particl
Page 157 and 158:
DEM is a numerical modeling techniq
Page 159 and 160:
Table 5.4 Variations of each model
Page 161 and 162:
Test No. 1-sphere Table 5.6 Combina
Page 163 and 164:
Table 5.7 Properties of the four pa
Page 165 and 166:
also drawn with the standard 31.75-
Page 167 and 168:
Both the actual particle motions an
Page 169 and 170:
5.4.1 Bulk Density Test Bulk densit
Page 171 and 172:
as the number of spheres in a parti
Page 173 and 174:
With tradeoffs between bulk density
Page 175 and 176:
Bardet, J. P., and Q. Huang. 1993.
Page 177 and 178:
Herrman, T. J., M. A. Boland, K. Ag
Page 179 and 180:
I: theory, model development and va
Page 181 and 182:
Zhang, X., and L. Vu-Quoc. 2002. A
Page 183 and 184:
from physics. A mechanistic model o
Page 185 and 186:
coefficients are given, respectivel
Page 187 and 188:
26% of the radiated energy. Thus, i
Page 189 and 190:
6.2.3 Three-Dimensional (3D) Modeli
Page 191 and 192:
Figure 6.1 Initial 3D simulation du
Page 193 and 194:
(a) (b) Figure 6.2 Quasi-2D simulat
Page 195 and 196:
left hand side (LHS) opening Width
Page 197 and 198:
Figure 6.4 Schematic diagram of the
Page 199 and 200:
After the clear soybean handling, t
Page 201 and 202:
Instantaneous Commingling (%) Insta
Page 203 and 204:
Average Commingling (%) in Discrete
Page 205 and 206:
Instantaneous Commingling (%) 6.0 5
Page 207 and 208:
(a) (b) Figure 6.12 Quasi-2D (6d_vi
Page 209 and 210:
Figure 6.15 Quasi-2D (6d_vib0_gate)
Page 211 and 212:
Slide gate (a) (b) Figure 6.16 Quas
Page 213 and 214:
Average Commingling (%) in Discrete
Page 215 and 216:
and grain handlers reduce costs dur
Page 217 and 218:
Kawaguchi, T., M. Sakamoto, T. Tana
Page 219 and 220:
Zhou, Y. C., B. H. Xu, A. B. Yu, an
Page 221 and 222:
• For both wheat and shelled corn
Page 223 and 224:
Appendix A - Supporting Data Data f
Page 225 and 226:
Table A.7 Pellet durability index (
Page 227 and 228:
Table A.14 Initial mass of corn sam
Page 229 and 230:
Table A.20 Percentage of whole and
Page 231 and 232:
Table A.26 Percentage of corn dust
Page 233 and 234:
Table A.32 Mass flow rate of wheat
Page 235 and 236:
Cumulative Volume, % 100 90 80 70 6
Page 237 and 238:
Table A.42 Mass concentration of co
Page 239 and 240:
Cumulative Volume, % 100 90 80 70 6
Page 241 and 242:
Data for Chapter 5 Table A.52 Publi
Page 243 and 244:
Length (mm), l Width (mm), w Thickn
Page 245 and 246:
215 Seed Volume (mm 3 ), V Seed Den
Page 247 and 248:
Table A.58 Published physical prope
Page 249 and 250:
219 Table A.61 Published physical p
Page 251 and 252:
Length (mm), l Width (mm), w Thickn
Page 253 and 254:
223 Parameters Length (mm), l Width
Page 255 and 256:
225 2.07 ± 0.016 C 1.84 ± 0.016 C
Page 257 and 258:
227 Table A.69 Data of single-kerne
Page 259 and 260:
Table A.71 Coefficient of restituti
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Table A.84 Bulk density results fro
Page 275 and 276:
Table A.85 Angle of repose results
Page 277 and 278:
Table A.85 Angle of repose results
Page 279 and 280:
249 Bag No. Test No. Table A.87 Moi
Page 281 and 282:
Table A.91 Particle density of red
Page 283 and 284:
Table A.96 Instantaneous comminglin
Page 285 and 286:
Table A.100 Instantaneous commingli
Page 287 and 288:
257 Actual Sampling Time Interval,
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Instantaneous Commingling (%) Avera
Page 295:
Square-root of Pressure Drop , in.
show all

QUALITY CHANGES, DUST GENERATION, AND COMMINGLING ...

Create successful ePaper yourself

Delete template?

Save as template?