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

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Fi ure 13 EFFECT OF TOTAL PRESSQRE, HYDROGEN PRESSURE AND SAMPLE COMPOSITION ON Hz, CO AND CH, CONTENT IN PRODUCT GAS 'tot (PSI01 ': 800OC 'Hi0 Prio :ICool :Gob (I a PHz( Ria) T : 800' C Ptot: 365 Psi1 9:ICwl:Gob .800°C, Ptol:365 Psi0 PHz. 115 Psi0 24 tEPRI-CHAMPION OWESTLAND o NOBLE CO. A BURNING STAR * FRANCES 0 AOSSINGTON A UPPER HIAWATHA VUES SHOWN ARE AVERAGES OF AU DATA AT GIVEN CONDITIONS
EFFECTS OF PREOXIDATION ON PYROLYSIS BEHAVIOR AND RESULTANT CHAR STRUCTURE OF CAKING COALS P D. J. Maloney and R. G. Jenkins The Fuels and Combustion Laboratory The Pennsylvania State University, University Park, PA 16802 INTRODUCTION l Coal gasification processes may be divided into two stages. They are, the initial rapid release of volatile matter and the relatively slow gasification of the residual char. These two processes are not, however, totally independent be- 1, cause the heat treatment conditions under which coal pyrolysis occurs determine, ( to a large extent, the structure and reactivity of the remaining char (1). The ' importance of understanding devolatilization kinetics has long been recognized (2-6). However, it is surprising to note that very little information is available in the literature regarding the structure and reactivity of the chars produced 1 in these studies. The work described here is concerned with the utilization of bituminous (caking) coals in dilute phase, rapid heating gasification and combustion systems. Two highly caking coals were pyrolyzed in an entrained flow tube furnace system and devolatilization kinetics determined for each coal at temperatures of 900 and 1000°C. Structural properties of the chars collected in this work were then analyzed. In addition, the effects of mild preoxidation of these coals upon their subsequent pyrolysis behavior were examined. Samples of each coal were oxidized to various levels prior to heat treatment. Devolatilization kinetics and structural properties of the chars produced were then analyzed. Results reported here follow the development of char structure with varying heat, treatment conditions and examine changes in char morphology which occur on preoxidation of these coals. This work is of practical importance in future design considerations for dilute phase gasifiers and of particular interest in gasification schemes where agglomeration of caking coals can cause serious problems. EXPERIMENTAL Pyrolysis experiments were conducted in an entrained flow tube furnace somewhat similar to that described by Scaroni et al. (7,8) and Nsakala and coworkers (9). Briefly, a dilute-phase coal stream is entrained in a primary carrier gas, passed through a water cooled probe and then injected into the center of a preheated secondary gas stream. The secondary gas stream enters the reaction zone at a temperature slightly above the furnace wall temperature so that upon mixing the combined gas stream attains the desired reaction temperature (? 10OC). The primary modes of coal particle heating are conduction from the gas and radiation from the furnace walls. Heating rates in excess of 10,OOO°C/s are estimated. Coal particles travel in a pencil stream down the axis of the furnace tube. Samples are collected and rapidly quenched (> 10,OOO°C/s quench rate) using a water cooled probe which is inserted up the axis of the furnace. Reaction times are varied by changing the position of the sampling probe relative to the injector. The operating conditions at each temperature studied are given in Table 1. Helium is used as the primary The secondary carrier gas and is adjusted to maintain isokinetic sample injection. gas is nitrogen. Weight loss due to pyrolysis was determined using ash as a tracer. The proximate analyses of the samples used in this work are presented in Table 2. The coals examined were PSOC-1133 a LV coal from the Lower Kittaning seam in Pennsylvania 25
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 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 52 and 53: actions, decreasing the secondary c
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
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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
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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
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i 1 \ ', References 1. 2. ( 3. 1 4.
Page 259 and 260:
\ ” 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
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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