the coking properties of coal at elevated pressures. - Argonne ...

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sulfur respectively. The ultimate analysis on a dry basis gave 6.9 percent ash, 4.4 percent hydrogen, 76.3 percent carbon, 1.1 percent nitrogen, 0.5 percent sulfur and 10.8 percent oxygen. The char sample probe was located on the center line of the reactor near the reactor exit (ca 150 cm from the burner inlet). Coal burnout was determined at each test condition from ASTM analysis of the ash sample, and by XRF analysis for titanium in the char Sample. TEST RESULTS Coal burnout results determined from a titanium mass balance in the char samples obtained are shown in Figure 2. Coal burnout was shown to be primarily a function of stoichiometric ratio, increasing from about 80-87 percent at SR = 0.6 (fuel rich) to greater than 95 percent at SR > 1.1 (Figure 2(al). The tests were not all conducted at a consistent set of stoichiometric ratios. idevertheless, interpolation of the curves (Figure 2(a)) at SR = 0.6, 0.9, and 1.2 has permitted the effect of swirl in the secondary air stream to be determined (Figure 2 (b)). The effect of stoichio.metric ratio is still quite pronounced. The effect of secondary swirl on coal burnout is small. The combustion of pulverized coal is very complex and the influences of secondary swirl, mixing rate, stoichiometric ratio, etc. are just beginning to be understood (1-6). An ASTM analysis of the char samples for ash and titanium as a tie component are given in Figure 3. Titanium burnout is higher in every case than the ash burnout, indicating that titanium is a better tracer than ash. The extent of ash loss, equivalent to an ash burnout, has also been determined from the titanium data. A set of parametric ash loss lines have also been constructed on Figure 3 for comparison (10 percent, 20 percent, 30 percent, 40 percent, and 50 percent). Ash losses of 15 to 60 percent can be observed by the superposition of the data on the various ash loss lines. The extent of ash loss is large compared to earlier work at this laboratory with a bituminous coal (6). However, the difference in coal type, ash composition, and moisture level could account for these differences. Ash loss has little effect on coal burnout at very high burnout levels. Figure 4 shows the error in burnout due to ash loss at several different burnout levels. At burnout values of 95 percent, ash losses of 40-50 percent create differences of only 2-3 percent in burnout estimates. Hence at moderate ash loss (20-40 percent) and high burnout values (greater than 95 percent burnout) the ash tracer burnout values are almost as accurate as the titanium-based burnout values. However, if burnout is below 95 percent then burnout based on titanium gave significantly improved results. Asay (12) has recently completed as set of pulverized coal combustion tests at the same secondary swirl numbers and at nearly the same stoichiometric ratios for this Wyoming coal. Carbon burnout data obtained from these tests with a complete gas coumposition and an argon tracer mass balance are compared in Figure 5 to the titanium analysis coal burnout data reported above. In general, coal burnout is expected to be from 1-2 percent higher than carbon burnout because of the more complete release of the hydrogen from the coal. In general, the agreement between burnout values from the gas analysis and from the titanium analysis is good at SR > 0.9. At SR = 0.6 however, the burnout values determined from the gas analysis are much lower. Asay (12) is still reviewing this discrepancy but it is thought that the data from the titanium analysis are superior. One possible explanation is that the gas data represent an integration of radial gas composition profiles near the reactor exit while the titanium data are based on centerline samples. 170
\ ? CONCLUSIONS Titanium can accurately be determined in char samples by using the internal standard method of XRF calibration. Errors of i 2-3 percent are incurred mostly I from sample preparation inaccuracy. X-ray fluorescence instrument error is less I than f 0.4 percent. Titanium compounds in ash are more stable than the total ash constituents and hence provide a solid phase tracer to complete overall mass balances with increased accuracy. Burnout calculations are improved by as much as 20 percent at burnout values less than 95 percent and with high ash loss. Vhen coal burnout level is above 95 percent, titanium provides only 1-2 percent increased accuracy in the burnout calculation. Use of the titanium tracer also provides a method of calculating ash loss. Up to 60 percent of the ash was lost in these combustion tests. This loss is the sum of the losses due to vaporization in the flame and dissolution into the quench water. ACKNOWLEDGEMENTS Blaine Asay, Steven Zaugg, and Rodney LaFollette assisted in the combustion tests while technician, drafting, and secretarial services were provided by Michael R. King, Kathleen Hartman, and Ruth Ann Christensen, respectively. This research project was supported by the EPRI under contract RP-364-2 with Mr. John Dimer as project officer, and by the Brigham Young University Research Division. REFERENCES 1. L.D. Smoot, P.O. Hedman. "Mixing and Kinetic Processes in Pulverized Coal Combustors." Final report prepared for EPRI, Contract ib. RP-364-1, August 1978. 2. L.D. Smoot, P.O. Hedman, and P.J. Smith. "Mixinq and Kinetic Processe in Pulverized -Coal Combustor-s." 364-1-3, October 1979. Final report prepared -for EPRI, Contract No. RP- 3. L.D. Smoot, P.O. Hedman, and P.J. Smith. "Cornbustion Processes in a Pulverized Coal Combustor." Final report prepared for EPRI, Contract No. RP- 364-2, August 1981. 4. J.R. Thurgood, L.D. Smoot, and P.O. Hedman. "Rate bieasurernents in a Laboratory-Scale Pulverized Coal Technology, 1, 1980, pp. 213-225. Combustor." Combustion Science and 5. D.P. Rees, L.D. Smoot, and P.O. Hedman. "Nitrogen Oxide Formation Inside a Laboratory Pulverized Coal Combustor." 18th Synposiun (International) on Combustion, The Combustion Institute, Pittsburgh, Pennsylvania, 1981 9 PP. T305-1311. 6. N.S. Harding, L.D. Smoot, and P.O. Hedman. "Nitrogen Pollutant Formation in a pulverized Coal Combusor: The Effect of Secondary Stream Swirl .I' accepted for publication in AIChE Journal, 1982. 7. H. Kobayashi,,, J.B. Howard and A.F. Sarofim. "Coal Devolatilization at High Temperatures. 16th Symposium (International on Combustion, Combustion Institute, Pittsburgh Pennsylvaniz, 1977, p. 411.
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I / The Coking Properties of Coal a
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Procedure : Hand picked lunips of c
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Apparatus: The equipment for this t
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the total pressure on the swelling
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A comparison of the results obtaine
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was used, however, general trends a
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1 D 13 3 G
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Table 8 L_ Effect os FaeO Compo.lrl
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i-l SPARE SAblPLE Plortlc 209 Figur
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- z c 100,000 50,000 10,000 0 n 5,0
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Flnure 9 SWELLltlG PROPERTIES OF PI
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Fi ure 13 EFFECT OF TOTAL PRESSQRE,
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TABLE 1. OPERATING CONDITIONS Opera
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1. . 2. 3. 4. 5. 6. 7. 8. 9. REFERE
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Figure 4. SCANNING ELECTRON MICROGR
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Turkgodan et al. (18) studied the p
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Materidl balance on packed bed Boun
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These phenomena iiiay be described
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Walker, P. L., Rusinko, F., and Aus
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-""I- *I,".. I Dlrf".,on Co.1flcl.n
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After a variable residence time, th
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Changes in Char Chemistry The infra
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20. 21. 22. 23. 24. 25. 26. 27. 28.
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0s-a 00-a OS'S 00-E os-2 00-2 02.1
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COAL PYROLYSIS AT HIGH TEMPERATURES
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actions, decreasing the secondary c
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01 40 60 TI MEISeC) 80 100 120 140
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Reaction Temperature OC In-situ Ini
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and the gas velocity is often repre
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The mathematical model developed he
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si sio Fraction of solid species i
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Table 2. Differential Equations Mod
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1 60 I I RUN KE-5 50 T.1121K(1557'F
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to condense excess steam, the press
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conversion-time data.* The integrat
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catalyzed and uncatalyzed runs were
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CATALYTIC EFFECTS OF ALKALI METAL S
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%me thermogravimetric measurements
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than in steam. Figure 9 shows data
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C - C02 REACTION C - H20 REACTION L
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1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
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n 'm L u. t m - L 84
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i 5360-096bw \ KINETICS OF POTASSIU
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t 5360-096pj There is an interactio
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1 I > \ i I 5360-096bw bed data. Be
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I 1. I 5360-096bw ranging from atmo
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uY.ku ICHlMAlIC OF MINI-FLUID BE0 R
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800-12-1133 -9 FIGURE IO CALCULATED
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Mexico coal. Table 1 shows an analy
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', Complete results from all runs c
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I the methanol down to atmospheric
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TABLE 3 -----______________________
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\ "I N z 107 c. . 0 0
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I. INTRODUCTION DIRECT METHANATION
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The catalyst development program fo
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Preparing process flow diagrams and
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\ \ i 1. 2,000 4,000 6,000 8,000 10
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(JMS-OlBM-2). The mass spectra were
Page 119 and 120: I I Fairbridge, R.W. (ed.) 1972, En
Page 121 and 122: v- W V z d 3 z m 4 ? P m W c3 W m N
Page 123 and 124: e. \ I , W 2 m 4 t- CI 99-79 noooo
Page 125 and 126: L Table I: Compositions of High Tem
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Page 131 and 132: The Determination of Mineral Distri
Page 133 and 134: pyrite crystals in framboids locate
Page 135 and 136: FIG. 1. TEM MICROGRAPH OF A HIGH VO
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Page 145 and 146: I Coal Ash Sintering Model and the
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Page 149 and 150: I this ash and other bituminous coa
Page 151 and 152: forming propensity. However, none o
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Page 155 and 156: CENTRAL ELECTRICIN RESEARCH LABORAT
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Page 159 and 160: temperature, sulfur species concent
Page 161 and 162: The facility is fired with coal usi
Page 163 and 164: Tests have been carried out to dete
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Page 167 and 168: I TITANIUM L Corn AS A TRACER FOR D
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Page 175 and 176: GFETC constructed a 0.2 square mete
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Page 181 and 182: FIG 9. Limestone bed material alter
Page 183 and 184: (4) Since the operating temperature
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Page 207 and 208: ACQUISITION DATA UNIT < I L- J (T)
Page 209 and 210: SAMPLING SYSTEM FOR FLUIDIZED BED A
Page 211 and 212: GAS SAMPLING WITH ORIGINAL PROBE-FI
Page 213 and 214: Remove the quartz tube (gas sample
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i \ ' 2.2. soz Emission and NOx Emi
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223
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Figure 9: Sulphur captLTre as 0 fun
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P SUMMARY OF TESTS Testing complete
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I Table 1 Comparison of Sulfur Capt
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, NITROGEN OXIDE REDUCTION Single-S
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0 The addition of air at the 96-inc
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m- Y i? 4: BO n 8 c Y l0- Bo- I I I
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E! w 2 z e Y 100 - 3 t 5 80- 0, 40
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0 f 0.so o'm: 0.300 0.zo - - A 5m 4
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&e- -A \ \ \ : ERCENT OVERBED AIR I
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PARTICLE ENTRAINMENT AND NITRIC OXI
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i 1' 1 ! I. i Chaung (15) showed th
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The maximum height that a large par
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3.0 Nitric Oxide Reduction in the F
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assumed to be identical to that of
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Nomenclature A *t cD ‘NO $3 _ _ _
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TABLE 2. OPERATING CONDITIONS AND E
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i 1 \ ', References 1. 2. ( 3. 1 4.
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\ ” Y) I 259
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t I 100 - - I I ] , I , I , I 'ii 9
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Feeding of the carbonaceous materia
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! Table 2 Proximate and ultimate an
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lb, , --pp---p-- 4 p? CHAR 1 Tu-IWO
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I CHAR Y Y /I TIME O i ' ' ' ' 1 '
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could not be assumed constant. Thus
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\ greatly acknowledged. Literature
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constructed and operated to demonst
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The experimental procedure for the
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atmospheric pressure fluidized bed
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1' TABLE 2 Screen Analysis of Sand
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n RECORDER I Ill I ’ NO. NOX THER
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\ 285 Y 0 I- 5 B 5 3 m "9 E5 3 uz 0
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CHAR1 TOC 0.85 M3/k 600 0 700 V 750
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f Durin all the experimental runs t
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Assuming that large coal particles
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i 7 -_ 0 m\o --n 0 W i 293 a\o 0
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The influence of particle size dist
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all the initial values of x for whi
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\ - + 1) x. = 1 bL/n YO Defining di
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$ m. 1 Results and Discussion Evalu
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kl k2 k' KC KD m m. m P N P R R g t
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UNBURNT FRACTION UNBURNT FRACTION m
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