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

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actions, decreasing the secondary char formation reactions ; at higher temperatures the increased pressure prevents some volatiles from escaping the solid and thus participating in secondary char-formation reactions. Similar results have been reported earlier (8) in a hydrogen atmosphere, wherein the amount of pyrolysis was found to increase only beyond about 20 atm pressure. Notably, in steam this effect is observed at lower pressures. The present studies also bring out the effect of temperature on this behavior. Further work in this area is necessary to confirm the anomalous results. Table 1 presents results of subsequent reactivity of chars formed by coal devolatilization. A comparison is shown of chars formed in-situ, as in the present mentod with chars formed separately and then reacted. Note that in-situ-formed char is a faccor two to ten times more reactive than chars formed separately. Thus, keeping the char at high temperatures for longer times before reaction apparently renders the char less reactive, and can be interpreted as a morphological rearrangemmt. These results are in agreement with previous results at this laboratory (U), and extend these results to higher temperature regimes. It is suggested that the char preparation method dramatically affects subsequent char reactivity. These effects must be considered in models of char reactivity and in the use of char reactivity data in coal-conversion reactor models and in the interpretation of pilot- unit data. CONCLUSIONS Devolatilization generally increases with temperature in a manner consis tent with the proposed three-stage mechanism for the evolution of volatiles. Results here show a plateau at 1200-14OO0C and a maximum devolatilization above 15OO0c. Reactive gases can interact with the freshly formed volatiles and affect the secondary char-forming reactions which can cause changes in the apparent percent pyrolysis. This was evident from the effects of moisture content, particle size, pressure and gaseous environment on the extent of pyrolysis. Reactivity of char formed in-situ and immediately reacted was found to be higher than reactivlty of chars formed separately and then brought into the reactive environment. It is suggested that morphological rearrangements may be important in pyrolysis and subsequent char reactions. ACKNOWLEDGlIENT This work was made possible by a grant from the Department of Energy, Contract NO. ET-78-S-01-3253. REFERENCES 1. Menster, M., O'Donnell, H. J. and Ergun, S., "Rapid Thermal Decomposition of Bituminous Coals," Am. &em. SOC., Div. of Fuel Chem. Preprints 2 (5) 94 (1970). 2. 3. Menster, M., O'Donnell, J. J., Ergun, S. and Friedel, R. A., "Devolatilization of Coal by Rapid Heating, " i n Coal Gasification, p. 1, Advances in Chemistry Series No. 131, Am. &em. SOC., Washington, D.C. (1974). Nsakala, N.Y., Essenhigh, R. H. and Walker, P. L., Jr., Fuel57 605 (1978). 4. Nsakala, N.Y., Essenhigh, R. H. and Walker, P. L., Jr., Comb. Sci. & Technol.8 - 16 -153 (1977). 5. Badzioch, S. and Hawksley, P. G. W., Ind. Eng. &em. Process Des. & Dev. 9 (4) 521 (1970). 52
6. 7. 1 a. i 9. 1 10. 11. 12. Kobayashi, H., Howard, J. B. and Sarofim, A. F., "Coal Devolatilization at High Temperatures, " 16th Intern. Symp. on Combustion, p. 411, The Combustion Institute, Pittsburgh, Pa. (1977). Scaroni, A. W., Walker, P. I,., Jr. and Essenhigh, R. H., Fuel 60 71 (1981). Anthony, D. B., Howard, J. B., Hottel, H. C. and Meissner, H. P., Fuel 2 121 (1976). Sears, J. T., Maxfield, E. A. and Tamhankar, S. S., "A Pressurized Themo- balance Appartus for Use in Oxidizing Atmospheres at High Temperatures,'' Ind. Eng. Chem. Fundamentals (submitted 1981). Suubert, E. M., Peters, W. A. and Howard, J. B., Ind. Eng. Chem. Process Des. & kv. 17 37 (1978). Agarwal, A. K. and Sears, J. T., Ind. Eng. Chem. Process Des. 6 Dev. 19 364 (1980). Linares-Solano, A., Mahajan, 0. P. and Walker, P. L., Jr., Fuel 58 327 (1979). Platinum Mrih Sample Hnldrr
Page 1 and 2: I / The Coking Properties of Coal a
Page 3 and 4: Procedure : Hand picked lunips of c
Page 5 and 6: Apparatus: The equipment for this t
Page 7 and 8: the total pressure on the swelling
Page 9 and 10: A comparison of the results obtaine
Page 11 and 12: was used, however, general trends a
Page 13 and 14: 1 D 13 3 G
Page 16 and 17: Table 8 L_ Effect os FaeO Compo.lrl
Page 18 and 19: i-l SPARE SAblPLE Plortlc 209 Figur
Page 20 and 21: - z c 100,000 50,000 10,000 0 n 5,0
Page 22 and 23: Flnure 9 SWELLltlG PROPERTIES OF PI
Page 24 and 25: Fi ure 13 EFFECT OF TOTAL PRESSQRE,
Page 26 and 27: TABLE 1. OPERATING CONDITIONS Opera
Page 28 and 29: 1. . 2. 3. 4. 5. 6. 7. 8. 9. REFERE
Page 30 and 31: Figure 4. SCANNING ELECTRON MICROGR
Page 32 and 33: Turkgodan et al. (18) studied the p
Page 34 and 35: Materidl balance on packed bed Boun
Page 36 and 37: These phenomena iiiay be described
Page 38 and 39: Walker, P. L., Rusinko, F., and Aus
Page 40 and 41: -""I- *I,".. I Dlrf".,on Co.1flcl.n
Page 42 and 43: After a variable residence time, th
Page 44 and 45: Changes in Char Chemistry The infra
Page 46 and 47: 20. 21. 22. 23. 24. 25. 26. 27. 28.
Page 48 and 49: 0s-a 00-a OS'S 00-E os-2 00-2 02.1
Page 50 and 51: COAL PYROLYSIS AT HIGH TEMPERATURES
Page 54 and 55: 01 40 60 TI MEISeC) 80 100 120 140
Page 56 and 57: Reaction Temperature OC In-situ Ini
Page 58 and 59: and the gas velocity is often repre
Page 60 and 61: The mathematical model developed he
Page 62 and 63: si sio Fraction of solid species i
Page 64 and 65: Table 2. Differential Equations Mod
Page 66 and 67: 1 60 I I RUN KE-5 50 T.1121K(1557'F
Page 68 and 69: to condense excess steam, the press
Page 70 and 71: conversion-time data.* The integrat
Page 72 and 73: catalyzed and uncatalyzed runs were
Page 74 and 75: CATALYTIC EFFECTS OF ALKALI METAL S
Page 76 and 77: %me thermogravimetric measurements
Page 78 and 79: than in steam. Figure 9 shows data
Page 80 and 81: C - C02 REACTION C - H20 REACTION L
Page 82 and 83: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
Page 84 and 85: n 'm L u. t m - L 84
Page 87 and 88: i 5360-096bw \ KINETICS OF POTASSIU
Page 89 and 90: t 5360-096pj There is an interactio
Page 91 and 92: 1 I > \ i I 5360-096bw bed data. Be
Page 93 and 94: I 1. I 5360-096bw ranging from atmo
Page 95 and 96: uY.ku ICHlMAlIC OF MINI-FLUID BE0 R
Page 97 and 98: 800-12-1133 -9 FIGURE IO CALCULATED
Page 99 and 100: Mexico coal. Table 1 shows an analy
Page 101 and 102: ', Complete results from all runs c
Page 103 and 104:
I the methanol down to atmospheric
Page 105 and 106:
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
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I I Fairbridge, R.W. (ed.) 1972, En
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v- W V z d 3 z m 4 ? P m W c3 W m N
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e. \ I , W 2 m 4 t- CI 99-79 noooo
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L Table I: Compositions of High Tem
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\ " \ I For all three coals, the pr
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4 , 1024 1024 3a 3b J Mineral Parti
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The Determination of Mineral Distri
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pyrite crystals in framboids locate
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FIG. 1. TEM MICROGRAPH OF A HIGH VO
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\ \ FIG. 5. SEM MICROGRAPH SHOWING
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\ , species. In fact, combustion ex
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1, It is possible to make a reasona
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\ i SURFACE AND BULK ENRICHMENT OF
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I Coal Ash Sintering Model and the
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5 carried out such sintering measur
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I this ash and other bituminous coa
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forming propensity. However, none o
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t I 153
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CENTRAL ELECTRICIN RESEARCH LABORAT
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157 18 I I a I
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temperature, sulfur species concent
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The facility is fired with coal usi
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Tests have been carried out to dete
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under which conditions sulfur speci
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I TITANIUM L Corn AS A TRACER FOR D
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E 6 i i h \ 1 1 \ on the XRF is cau
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\ ? CONCLUSIONS Titanium can accura
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NY) m * oa
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GFETC constructed a 0.2 square mete
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\: Stage 3. Sulfated ash-cemented a
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I FIG. 1. Initial ash coating on qu
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FIG 9. Limestone bed material alter
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(4) Since the operating temperature
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I I maximum particle diameter leavi
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! suspension chambers and cyclone f
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Pilot Plant of a Coal Fired Fluidiz
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After the fiscal year 1982, the fol
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MBC CBC Fig. 1 Boiler Structure 193
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\ i Table 2. Coal Properties Planne
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-2- more than 3 years, since 1977.
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, I B. 2 which temporarily raised t
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-6- abrasion rate at the bottom of
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\if F3.3 - Particulate Circulation
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\' I/O. analog 1/13. industrial I/O
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ACQUISITION DATA UNIT < I L- J (T)
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SAMPLING SYSTEM FOR FLUIDIZED BED A
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GAS SAMPLING WITH ORIGINAL PROBE-FI
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Remove the quartz tube (gas sample
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' ' The modifications have been com
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n n D 217
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With regard to the similarity parti
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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
Page 257 and 258:
i 1 \ ', References 1. 2. ( 3. 1 4.
Page 259 and 260:
\ ” Y) I 259
Page 261 and 262:
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 '
Page 271 and 272:
could not be assumed constant. Thus
Page 273 and 274:
\ greatly acknowledged. Literature
Page 275 and 276:
constructed and operated to demonst
Page 277 and 278:
The experimental procedure for the
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atmospheric pressure fluidized bed
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1' TABLE 2 Screen Analysis of Sand
Page 283 and 284:
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
Page 287 and 288:
CHAR1 TOC 0.85 M3/k 600 0 700 V 750
Page 289 and 290:
f Durin all the experimental runs t
Page 291 and 292:
Assuming that large coal particles
Page 293 and 294:
i 7 -_ 0 m\o --n 0 W i 293 a\o 0
Page 295 and 296:
The influence of particle size dist
Page 297 and 298:
all the initial values of x for whi
Page 299 and 300:
\ - + 1) x. = 1 bL/n YO Defining di
Page 301 and 302:
$ m. 1 Results and Discussion Evalu
Page 303 and 304:
kl k2 k' KC KD m m. m P N P R R g t
Page 305 and 306:
UNBURNT FRACTION UNBURNT FRACTION m
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