STUDIES ON ETHYLENEDIAMINE ASSISTED N-METHYL-2- PYRROLIDONE EXTRACTION OF COAL - SCALE UP OF THE PROCESS AND UTILIZATION OF THE SUPER CLEAN COAL
OBTAINED
BY
S H A IL A JA PA N D E
THESIS SUBM ITTED
IN THE FU LFILM EN T OF TH E REQUIREM ENTS FO R THE AW ARD OF THE
DEG REE OF
D O C T O R O F P H IL O S O P H Y
C EN TR E FOR ENERG Y STUDIES
INDIAN IN S T IT U T E O F T E C H N O L O G Y , D ELH I NEW D E L H I-110016, INDIA
JU N E 2000
. T. D ELHI. I
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C E R T IFIC A T E
This is to certify that the thesis entitled, "STUDIES ON E T H Y L E N E D IA M IN E A SSIST E D N -M E T H Y L -2-PY R R O L ID O N E E X T R A C T IO N O F C O A L - SCA LE UP O F TH E PR O C E SS AND U T IL IZ A T IO N O F T H E SU PE R C L E A N C O A L OBTAINED", being subm itted by Shailaja Pande to the Indian Institute o f T echnology, Delhi, for the award o f the degree o f D octor o f P hilosophy is a record o f original bonafide research w ork carried out under my supervision for the subm ission o f this thesis w hich to my know ledge has reached the requisite standard.
The thesis or any part o f this has not been subm itted to any other U niversity or Institute for the aw ard o f any degree or diploma.
Professor
Centre for E nergy Studies LI T., Delhi
N ew Delhi - 110016, India
A C K N O W L E D G E M E N T S
I express my sincere gratitude and indebtedness to Prof. D. K. Sharm a for his invaluable guidance, suggestions and help tow ards completion o f this work.
I am grateful to the D epartm ent o f Science and Technology, M inistry o f Science and Technology, G ovt, o f India, for providing financial assistance to carry' out the research work.
I express my gratitude to CM PDIL, Ranchi, Bihar for their kind help in arranging coal sam ples for the research work.
M any thanks are due to CCL, Ranchi, Bihar for providing coal samples o f Loiyo, Pindra, Kuzu and R ajrappa w ashery for the research work.
1 am equally thankful to ECL, Dishergarh, West Bengal for providing Sam la coal samples.
I am equally thankful to NECL, M argherita, Assam for providing Assam coal sample.
I am thankful to BTPS, Badarpur, New Delhi for providing Akash Kinari, Bachra, N orth Tisra, K aranpura D iw ar Khan and K aranpura Diwar H aslong coal samples.
Thanks are due to RSIC, CDRI, Lucknow, U P. for providing C. H, N analysis data o f coal samples.
Thanks are due to R&D Centre, NTPC, Noida, U P. for sulphur analysis o f coal samples
Thanks are due to the Department o f Biodiagenesis, Birbal Sahni Institute o f Palaeobotany, Lucknow, U P. for carrying out the petrographic analysis o f coal samples.
I express my sincere thanks to Prof. T. R. Rao and Dr. A. K. Bhaskarwar (D epartm ent o f Chem ical Engineering, IIT, Delhi), Prof. (M rs.) V. C haudhary (C entre tor Polymer Science and Engineering, IIT, Delhi) for their help, suggestions and discussions with them on various topics.
I also express my gratitude to D r.T .L .D h a m i o f NPL, Delhi and D r.S .K .Ja in o f IOC, Faridabad for their help in conducting graphitization and GPC studies, respectively.
I express my gratitude to Dr. M ehta (IDDC, IIT, Delhi) for guidance and useful discussions for fabrication o f steel extractor and the staff o f IDDC for the same.
I express my sincere thanks to J.J.Foam , Sahibabad, U P. for providing sam ples o f TDI, and stannous octoate.
Laboratory colleagues and friends - Dr. C. C . G iri, Dr. S u m an C h a h a r, D r. G.
YYadhawa. M r.A .D as, M r. B. K. T iw ari, M r. M . A h m a ru z z a m a n , M s. S u n ita , Ms.
M een ak sh i N an d a, M s. A n u ra d h a S a n tra , M r. P arv esh and M s. Ip sita R oy - equally deserve my sincere thanks for their help during my period o f work.
I also express thanks to Mr. Am brish K um ar and Mr. Kam al for assisting me in the laboratory during my period o f research work.
Last but not the least I would like to acknow ledge my fam ily m em bers, especially A parna, Siddhartha, Juhi, my husband A tul and my parents and others for their help and constant encouragem ent during my research work.
(SH A ILA JA PA N D E)
ABSTRACT
T he present thesis reports the results o f an experim ental research program m e with an aim to develop som e convenient chemical technique for rendering m axim um am ount ot coal extractable in common organic solvents under relatively m ilder conditions at atm ospheric pressure, without resorting to high pressure hydrogenation o f coal at elevated tem peratures using hydrogen-donor solvents. The thrust was on the use o f com m ercial and specific solvents for extraction o f coals to obtain super clean coal (SCC) as the prem ium product. Twenty Indian coals varying from lignite to high rank bitum inous coals w ere selected for extraction studies. The aim was to render maximum am ount o f coal extractable in the selected solvent system by using relatively shorter extraction tim es o f 2 to 4h.
Studies were undertaken on the use o f N -m ethyl-2-pyrrolidone (NM P) as a solvent for extraction o f coals under reflux conditions at atmospheric pressure. However, extraction yield o f m ost o f the coals studied was not found to be good in NMP. Studies w ere carded out to find a solvent system for im proving extraction yield o f coals.
Chinakuri coal, a non-coking low rank bitum inous coal was selected as the coal for study and its extractability characteristics were determined in various solvents. Amongst the solvents studied, ethylenediam ine (EDA) was found to be the most effective solvent for extraction- followed by NMP. W ork was undertaken on the use o f stepw ise successive extraction o t Chinakuri coal, a low rank bitum inous coal and Loiyo coal, a high rank bitum inous coal to study the enhancem ent in the total extraction yield o f coals by using solvents in a stepw ise process. Amongst the various solvent sequences studied, it was
found that maximum amount o f coal was rendered extractable when N M P-ED A solvent sequence w as used i.e., residual coal obtained after NMP extraction was further extracted with EDA. The total extraction yield o f Chinakuri coal in N M P-ED A solvent extraction sequence w as 34% compared to only 10% in NMP and 21% in ED A in separate sets ot extractions. The total extraction yield o f Loiyo coal in N M P-ED A solvent extraction sequence w as 36% compared to 27% in NM P and 16% in EDA in separate extractions.
The total extraction yield o f different coals in NMP followed by EDA successive extraction w as found to fall in the range o f 14 to 36%. Swelling studies o f original and residual C hinakuri and Loiyo coals in N M P and EDA w ere carried out to understand the m echanism o f successive extraction o f coals. Swelling studies o f original coals were also perform ed by using NM P+EDA (1:1; vol./vol.) mixture of solvents. Interestingly, m axim um sw elling was obtained with the m ixture followed by that with EDA and then with N M P. H ence work w as undertaken to study further enhancem ent in the extraction yield o f coals by adopting the approach o f using a m ixture o f solvents for extraction. It was found that a solvent system o f NM P containing a small am ount o f EDA (term ed as e,N ) rendered enhanced am ount o f coal extractable in NM P u nder-reflux conditions com pared to NM P alone and ED A alone. The extraction yields o f Chinakuri and Loiyo coals in e,N w ere found to be 34% and 62% respectively. It was found that for all coals studied, extraction in N M P was enhanced by addition o f a small am ount o f ED A to NMP and this w as also m ore than that in EDA. Stepw ise successive extraction was also found to be possible in e,N solvent system and w as found to be better than N M P-ED A solvent sequence. T he total extraction yield o f coals in e,N followed by e,N stepw ise successive
extraction w as found to fall in the range o f about 45 to 70% com pared to 14 to 36% by using N M P -E D A solvent sequence.
B ased upon the success o f the e,N solvent system, work w as also undertaken to study the solvent extraction o f coals at room tem perature using a mixture o f solvents.
Chinakuri and Loiyo coals w ere extracted with NMP, EDA and NM P+EDA (1:1;
vol./vol.) mixed solvent at room tem perature. The extraction yield was maximum in the third case. Extraction yields varying from 25 to 40% were obtained in studies carried out for seventeen Indian coals.
M aterial balance studies w ere carried out on the recovery o f NMP and EDA after solvent extraction o f coal with N M P containing a small amount o f EDA and N M P+ED A (1:1) solvent system.
The extracts and residues obtained from solvent extraction were characterized by elemental and proxim ate analyses and IR spectral studies The m olecular w eights o f
NMP and e,N extracts w ere determined by GPC. The calorific values o f original coals, extracts and residual coals were determined. Extracts were found to have a higher
calorific value than the residual and original coals.
K inetics o f swelling o f Chinakuri coal in NM P, EDA and N M P+ED A (1:1) mixed solvent system w ere studied. It was found that the diffusion o f NMP, EDA and N M P+ED A (1:1) in coal was described by Fickian diffusion. The activation energies for the com bined diffusion and sw elling process w ere calculated. It was found that the activation energy barrier to swelling may be associated with the disruption o f hydrogen bonding interactions in coal. The studies on the external (effect o f stirring) and internal mass transfer (effect o f particle size) in e,N extraction o f Chinakuri coal were carried out.
It was found that the extraction o f Chinakuri coal in e,N under reflux conditions i.e. batch m ode did not suffer from external mass transfer limitations. There w as little effect o f particle size on the extraction o f coal in e,N. The kinetics o f solvent extraction o f Chinakuri coal in e,N was studied. It was found that the kinetics o f the extraction process was best described in tw o stages. The extraction process was diffusion-controlled in stage I with an order o f 0.66 and followed first order kinetics in stage II. The activation energies o f stage I and stage II processes w ere calculated. The extraction process was found to be lim ited by diffusion and under physical control involving the breakage o f only physical interactions such as van der W aals’ forces and hydrogen bonds present in coal.
Based upon the results o f solvent extraction o f coal in e,N studies w ere extended tow ards scaling up the process o f solvent extraction o f coal at atm ospheric pressure conditions. A sem i-continuous flow -through glass extractor, which could handle 1 to 2.5 kg o f coal w as fabricated. A bout 1-2.5 kg o f coal w as successfully extracted in the glass extractor for 2h.
Studies w ere carried out tow ards the potential uses o f SCC. obtained from solvent extraction o f coal with e,N solvent system. C oking characteristics o f SCC, residual and original Chinakuri coal w ere studied. SCC w as found to show coking properties. Residual and original Chinakuri coal w ere found to be non-caking. Studies w ere also perform ed on the graphitization o f SCC. G raphitization characteristics w ere studied by carrying out XRD and elem ental analyses o f the graphitized sample.
The use o f SCC for making value added products such as value added polym ers from coal was studied. SCC was oxidized and then depolym erized by phenolation. The
depolym erization o f oxidized SCC was com pared with the depoiym erization o f oxidized original Chinakuri coal. It was found that oxidized SCC showed greater degree o f depolym erization as determined by the percent phenol added to coal after depolym erization. Hence, the depolym erized-oxidized SCC was used for m aking phenol- based polym ers such as phenol-form aldehyde resins and polyurethanes. The prelim inary experim ents show that depolym erized-oxidized SCC may be used for making value added resins.
Som e studies w ere also carried out on the effect o f pretreatm ents such as oxidation, m icrowave heating and therm osolvolysis on the solvent extraction o f coal with NM P, ED A , e,N and room tem perature N M P+ED A (1:1) extraction o f Chinakuri coal.
The effects o f these pretreatm ents on the coking properties o f SCC obtained w ere also studied.
C O N T E N T S
AB ST R A C T
LIST O F FIG URES
LIST OF TA BLES
A B B R E V IA T IO N S
C H A PTER 1 IN T R O D U CTIO N
C H A PTER 2 L IT E R A T U R E REVIEW
2.1 Indirect coal liquefaction (Fischer-Tropsch synthesis) 2.2 Direct hydrogenation o f coal
2.2.1 Direct liquefaction
2.2.2 Solvent extraction processes 2.3 Solvent extraction o f coal
2.3.1 Extraction o f coal with coal-derived solvents
2.3.2 Solvent extraction o f coal in N -m ethyl-2-pyrrolidone and specific solvents
2.3.3 Swelling study o f coal
2 .3 .4 Effect o f pretreatm ent o f coal
2 . 3 . 5 M e c h a n i s m o f s o l v e n t e x t r a c t i o n o f c o a l 2.3 .6 Kinetics o f swelling
2.3.7 Kinetics o f solvent extraction
2.4 D ep o ly m erizatio n o f coal by p h e n o la tio n 59 2.5 In fra re d sp e c tra l stu d ies o f coal a n d coal p ro d u c ts 62 2.6 G el p e rm e a tio n c h ro m a to g ra p h ic (G P C ) stud ies 64
2.7 N on-fuel uses o f coal 66a
2.8 C o k in g p ro p e rtie s o f coal 66b
C H A P T E R 3 E T H Y L E N E D L A M IN E A SS IS T E D S O L V E N T E X T R A C T IO N O F C O A L IN N -M E T H Y L -2 -P Y R R O L ID O N E - S Y N E R G IS T IC E F F E C T O F E T H Y L E N E D IA M IN E ON E X T R A C T IO N O F C O A L IN N -M E T H Y L -2 -P Y R R O L ID O N E
3.1 In tro d u c tio n 67
3.2 E x p e rim e n ta l section 73
3.2.1 Solvent extraction o f coals w ith a single solvent 74 3 .2.2 Stepw ise successive extraction o f Chinakuri coal
with different solvents 74
3 .2.3 W ashing o f residual coal 74
3 .2.4 R ecovery o f solid extracts 75
3 .2.5 Stepw ise successive extraction o f Chinakuri and Loiyo coal 75 with N M P and EDA
3 .2.6 R ecovery o f solid extracts 76
3 .2.7 Solvent extraction o f C hinakuri coal in NMP containing a 77 small am ount o f a different solvent and in a solvent containin'-O
a small am ount o f ED A
3 .2.8 Solvent extraction o f coals in NM P containing a small 77 amount o f ED A
3 .2.9 Recovery o f solid extracts 78
3.2.10 Extraction o f C hinakuri coal w ith NM P after pretreatm ent 78 o f coal w ith a small am ount o f EDA and removal o f EDA
3 .2.11 Recovery o f solid extracts 78
3 .2.12 Stepwise successive extraction o f coals in NMP containing 79 a small am ount o f ED A (e,N -e,N )
3 .2.13 Recovery o f solid extracts 79
3.2.14 Calculation o f extractability 79
3 .2.15 Swelling m easurem ent 80
3 .2.16 Porosity studies 81
3.2.17 Infra-red (IR) spectral studies 81
3 .2.18 Gel perm eation chrom atographic (GPC.) studies 8 1
3.2.19 Correlation studies 81
3.3 R esults 82
3.3.1 S o l v e n t e x t r a c t i o n o f C h i n a k u r i c o a l in d i f f e r e n t s o l v e n t s 82
3 . 3 . 2 S w e l l i n g o f C h i n a k u r i c o a l in d i f f e r e n t s o l v e n t s 82
3. 3 . 3 S t e p w i s e s u c c e s s i v e e x t r a c t i o n o f C h i n a k u r i c o a l 87 w i t h d i f f e r e n t s o l v e n t s e q u e n c e s
3.3.4 Stepwise successive solvent extraction o f Chinakuri coal and Loiyo coal in NM P and EDA
3 .3 .5 Swelling o f Chinakuri and Loiyo coals
3 .3 .6 Stepw ise successive extraction o f coals using NM P-ED A solvent sequence
3.3.7 Extraction o f different coals with N M P and EDA (effect o f rank)
3.3.8 Swelling o f coals in N M P+ED A (1:1, vol./vol.) mixed solvent system
3 .3 .9 Extraction o f Chinakuri coal with N M P containing
different am ounts o f ED A (optim ization o f coal to ED A ratio) 3.3.10 Solvent extraction o f Chinakuri coal in NMP containing
a small am ount o f a different solvent and in a solvent containing a small am ount o f EDA
3 .3.11 Extraction o f Chinakuri coal w ith NM P after pretreatm ent o f coal w ith a small am ount o f ED A and removal o f EDA
3 .3.12 Stepwise successive extraction o f Chinakuri coal and Loiyo coal in e,N (e,N -e,N -e,N )
3.3.13 Swelling o f the original and residual coals with pyridine 3.3.14 Extraction o f coals with e,N (effect o f coal rank and property) 3.3.15 Stepwise successive extraction o f coals in e,N (e,N-e,N )
3 .3 .16 Elem ental analyses o f the SCC and RC and recovery 121 o f N M P and EDA
3.3.17 IR studies 126
3.3.18 C haracterization o f the extracts and residues from 126 e,N solvent extraction
3.3.19 GPC studies 138
3.4 Discussion 138
3.4.1 Extraction o f coals with NMP 138
3.4.2 Extraction o f Chinakuri coal with different solvents 139
3.4.3 Extraction o f coals with EDA 141
3.4.4 Extraction o f Chinakuri coal and Loiyo coal with different 142 solvent sequences using NMP and EDA
3.4.5 Extraction o f Chinakuri coal and Loiyo coal using a mixture 147 o f NM P and EDA
3 .4.6 Solvent extraction o f Chinakuri coal in different mixed 151 solvent systems
3 .4.7 Effect o f extraction o f Chinakuri coal with NMP after 153 pretreatm ent o f coal with a small amount o f EDA and
removal o f EDA
3.4.8 Swelling o f the original and residual coals with pyridine 154 3.4.9 Stepwise successive extraction o f Chinakuri coal and Loiyo I 55
coal in e,N (e,N-e,N -e,N )
3.4.10 Effect o f coal rank and property I 56
3 .4.11 IR spectral analyses 159 3 .4.12 C haracterization o f extracts and residues from e,N extraction 162
3.4.13 GPC studies 163
3.5 C onclusions 165
C H A P T E R 4 O R G A N O -D IS S O L U T IO N O F C O A L IN N -M E T H Y L -2 - P Y R R O L ID O N E + E T H Y L E N E D LAM INE (1:1; V O L ./V O L .) M IX E D S O L V E N T S Y S T E M
4.1 In tro d u c tio n 167
4.2 E x p erim en tal sectio n 171
4.2. i O rgano-dissolution o f Chinakuri coal in a single solvent 172
4 2.2 W ashing o f residual coal 172
4 2.3 Recovery o f SCC 172
4.2.4 O rgano-dissolution o f coals in N M P+ED A (1:1) (vol./vol.) 173
4.2.5 Recovery o f SCC 173
4.2.6 Stepwise successive extraction o f C hinakuri coal in 173 N M P+ED A (1:1)
4 2 7 Recovery o f SCC 174
4.2.8 C alculation o f extractability 174
4.2.9 Swelling measurem ent 174
4.2.10 Infra-red (IR) spectral studies 175
4.3 Results 175
4.3.1 O rgano-dissolution o f Chinakuri coal and Loiyo coal 175
in NMP, EDA and N M P+ED A (1:1) mixed solvent system (cosolvency effect) at room tem perature
4.3 .2 Extraction o f Chinakuri coal in other solvents and mixed solvents 176 4.3.3 Effect o f coal to N M P+ED A (1:1) ratio on the yield o f SCC 180 4.3.4 Effect o f N M P to EDA ratio on the yield o f SCC 180 4.3.5 Effect o f tim e o f extraction on the yield o f SCC 180 4.3.6 Effect o f tem perature on the yield o f SCC 186 4.3 .7 Stepwise successive organo-dissolution o f Chinakuri coal 186
(N +E-N +E)
4.3.8 Cooperative effects in sw elling o f Chinakuri coal 188 4.3.9 Swelling o f the original and residual coals with pyridine 190 4.3.10 O rgano-dissolution o f coals in N M P+ED A (1:1) mixed 190
solvent system
4.3 .11 Swelling o f coals 190
4 .3 .12 Effect o f coal rank and property 195
4.3.13 Elemental analyses o f SCC and recovery o f NM P and EDA 195
4.3.14 IR studies 200
4.3 .15 Characterization o f the extracts from NMP+ EDA (1:1) 200 solvent extraction
4.4 Discussion 208
4.4. 1 C o o p e r a t i v e e f f e c t s in s o l v e n t s w e l l i n g o f c o a l 2 0 8
4.4.2 Synergistic effect o f the mixed solvent in organo-dissolution 211 4.4.3 Effect o f tem perature on the yield o f SCC 216 4.4.4 Effect o f NMP to EDA ratio on the yield o f SCC 217 4.4.5 S w e llin g o f or ig in a l and resid u al c o a ls in p y rid in e 218 4.4.6 Successive extraction o f coal in N M P+ED A (1 1) (N +E-N +E) 219 4.4.7 O rgano-dissolution o f Chinakuri coal in different mixed 219
t
solvent systems
4.4.8 S w e llin g o f c o a ls in m ix e d s o lv e n t s y s te m 221 4.4.9 Effect o f coal rank and property on organo-dissolution o f coal 221
4.4.10 IR spectral analyses 222
4.4.11 Characterization o f extracts from N M P+ED A (1:1) 224 extraction
4.5 C onclusions 225
C H A PT E R 5 STUDIES ON TH E M E C H A N ISM OF SO L V E N T E X T R A C T IO N OF COAL USING N -M E T H Y L -2-P Y R R O L ID O N t C O N T A IN IN G A SM A LL A M O U N T O F E H T Y L E N E D IA M IN E - ST U D IE S ON THE K IN ETICS O F SO L V E N T DIFFU SIO N A N D S O L V E N T EX TRA C TIO N O F COAL
5.1 Introduction 226
5.2 Experim ental section 237
5.2.1 K inetics o f sw elling o f coal by the solvent 237 5.2.2 K in e tic s tu d ie s o f s o lv e n t e x tr a c tio n 238
5.2.3 O ptim ization o f coal to solvent ratio 238 5.2.4 External mass transfer studies (E ffect o f stirring) 239 5.2.5 Internal mass transfer studies (E ffect o f particle size) 239
5.3 R esults a n d discussion 240
5.3.1 K inetics o f solvent diffusion in coals 240
5.3 .2 O ptim ization o f coal to solvent ratio 263
5.3.3 Effect o f particle size 265
5.3.4 Effect o f stirring 265
5.3.5 K inetic studies o f solvent extraction o f coal 268
5.3.6 External mass transfer studies 282b
5.3.7 Internal mass transfer studies 282d
5.4 C onclusion s 282d
C H A P T E R 6 S T U D IE S ON S C A L IN G UP O F O R G A N O -R E F IN IN G P R O C E S S AND U T IL IZ A T IO N O F S U P E R C L E A N C O A L O B T A IN E D
6.1 In tro d u c tio n 283
6.1.1 Studies on scaling up o f organo-refining process 284
6.1.2 U tilization o f super clean coal 285
6.1.2.1 Coke and graphite from super clean coal 286
6.1.2.2 D epolym erization studies 287
6.1.2.3 Use o f depolym erized oxidized SCC for polym er 289 preparations - Polyurethanes and Resol
6.1.2.4 Effect o f pretreatm ents on solvent extraction 290 o f coals and coking properties o f SCC obtained
6.2 Experim ental section 291
6.2.1 Scaling up o f organo-refining process 291
6.2.1.1 Solvent extraction o f coal in NM P and in NM P 291 containing a small am ount o f ED A at laboratory
scale (Batch extraction)
6.2.1.2 Solvent extraction o f coal in N M P containing a 291 small am ount o f E D A in a flow -through glass
extractor (sem i-continuous semi-batch)
6.2.1.3 Fabrication o f steel extractor 292
6.2.2 C oke and graphite from super clean coal 293
6.2.2.1 Free sw elling index (FSI) test 293
6.2.2.2 Coking and graphitization o f SCC 293
6.2.2.3 X -ray diffraction (X RD ) studies 294
6.2.3 D epolym erization studies 294
6.2.3.1 D epolym erization o f coal 295
6.2.3 .2 O xidation and depolym erization o f coal 295
6.2.4 Coal-based polyurethanes 296
6.2.4.1 Preparation o f polyurethane 296
6.2.4.2 Preparation o f specim en for cross-hatch 297 adhesion (CHA) test
6.2.4.3 Preparation o f specim en for shear test 298
6.2.5 C oal-based phenol-form aldehyde resins (Resol) 298
6.2.5.1 Preparation o f resol 298
6.2.6 E ffect o f pretreatm ents on solvent extraction o f coal 299 and coking properties o f SCC obtained
6.2.6.1 Solvent extraction o f oxidized coal 299 6.2.6.2 Solvent extraction after preheating (therm osolvolysis) 300 6.2.6.3 Solvent extraction after m icrowave heating 300
o f coal (shock heating)
6.2.6.4 O rgano-dissolution o f coal in the presence o f 300 ultrasonic irradiation
6.2.6.5 Free sw elling index (FSI) test 300
i * % '
6.3 Results and D iscussion 301
6.3.1 Studies on scaling up o f organo-refining process 301 6.3.1.1 Solvent extraction o f coal in NM P and in NM P 301
containing a small am ount o f EDA at laboratory scale (B atch extraction)
6.3.1.2 Solvent extraction o f coal in recirculatory flow -through 301 glass extractor
6.3.1.3 Fabrication o f flow -through steel extractor 302
6.3.2 Coking and graphitization studies 306
6 .3 .2 .1 FSI tests 306
. 6.3 2.2 Graphitization o f SCC 310
6.3.3 D epolym erization studies 314
6.3 .4 Coal-based polyurethanes 317
6.3.4.1 M echanical properties 317
6.3.5 Coal-based phenol-form aldehyde resins (Resol) 320 6.3 .6 E ffe c t o f p retre a tm en ts o n s o lv e n t e x tr a c tio n o f c o a l and 322
coking properties o f SCC obtained
6.3 .6.1 Effect o f oxidation 322
6.3 .6 2 Effect o f preheating (therm osolvolysis) 323
6.3 .6.3 Effect o f m icrowave heating 323
6.3 .6.4 Effect o f ultrasonic irradiation on organo-dissolution 324 6.3 .6.5 Effect o f oxidation and preheating on coking properties 324
6.4 C on clusion s 326
C H A P T E R 7 C O N C L U S IO N S 328
R E F E R E N C E S 332
A B O U T T H E A U T H O R 345
