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Title: Increase in extraction yields of coals by water treatment: Beulah-Zap lignite

Abstract

In a previous paper, we have reported that water pretreatments of Argonne premium coals, Pocahontas No. 3 (PO), Upper Freeport (UF), and Illinois No. 6 (IL) at 600 K increased greatly the room-temperature extraction yields with a 1:1 carbon disulfide/N-methyl-2-pyrrolidinone (CS{sub 2}/NMP) mixed solvent. In this paper, the water treatment of Beulah-Zap (BZ) lignite has been carried out and the results obtained were compared with those for the three bituminous coals above. The extraction yields of BZ with CS{sub 2}/NMP increased from 5.5% for the raw coal to 21.7% by the water treatment at 600 K. Similar to the other three coals, the water treatments at 500 K gave little increase in the yields. The larger decrease in oxygen content and hydrogen-bonded OH and the increase in the methanol swelling ratio by the water treatment suggest that the yield enhancements for BZ are attributed to the removal of oxygen functional groups and the breaking of hydrogen bonds to a greater extent than that for IL. From the characterizations of the treated coals and the extraction temperature dependency of their extraction yields, it is suggested that, for high-coal-rank coals, PO and UF, the breaking of noncovalent bonds such as {pi}-{pi} interactionsmore » between aromatic layers and hydrogen bonds is responsible for the extraction yield enhancements. 14 refs., 3 figs., 2 tabs.« less

Authors:
; ; ; ;  [1]
  1. National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan)
Publication Date:
OSTI Identifier:
20862165
Resource Type:
Journal Article
Resource Relation:
Journal Name: Energy and Fuels; Journal Volume: 21; Journal Issue: 1; Other Information: iino@cat-v.ne.jp
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; LIGNITE; SOLVENT EXTRACTION; MIXED SOLVENTS; CARBON SULFIDES; PYRROLIDONES; YIELDS; WATER; BITUMINOUS COAL; CHEMICAL BONDS

Citation Formats

Masashi Iino, Toshimasa Takanohashi, Takahiro Shishido, Ikuo Saito, and Haruo Kumagai. Increase in extraction yields of coals by water treatment: Beulah-Zap lignite. United States: N. p., 2007. Web. doi:10.1021/ef060099g.
Masashi Iino, Toshimasa Takanohashi, Takahiro Shishido, Ikuo Saito, & Haruo Kumagai. Increase in extraction yields of coals by water treatment: Beulah-Zap lignite. United States. doi:10.1021/ef060099g.
Masashi Iino, Toshimasa Takanohashi, Takahiro Shishido, Ikuo Saito, and Haruo Kumagai. Mon . "Increase in extraction yields of coals by water treatment: Beulah-Zap lignite". United States. doi:10.1021/ef060099g.
@article{osti_20862165,
title = {Increase in extraction yields of coals by water treatment: Beulah-Zap lignite},
author = {Masashi Iino and Toshimasa Takanohashi and Takahiro Shishido and Ikuo Saito and Haruo Kumagai},
abstractNote = {In a previous paper, we have reported that water pretreatments of Argonne premium coals, Pocahontas No. 3 (PO), Upper Freeport (UF), and Illinois No. 6 (IL) at 600 K increased greatly the room-temperature extraction yields with a 1:1 carbon disulfide/N-methyl-2-pyrrolidinone (CS{sub 2}/NMP) mixed solvent. In this paper, the water treatment of Beulah-Zap (BZ) lignite has been carried out and the results obtained were compared with those for the three bituminous coals above. The extraction yields of BZ with CS{sub 2}/NMP increased from 5.5% for the raw coal to 21.7% by the water treatment at 600 K. Similar to the other three coals, the water treatments at 500 K gave little increase in the yields. The larger decrease in oxygen content and hydrogen-bonded OH and the increase in the methanol swelling ratio by the water treatment suggest that the yield enhancements for BZ are attributed to the removal of oxygen functional groups and the breaking of hydrogen bonds to a greater extent than that for IL. From the characterizations of the treated coals and the extraction temperature dependency of their extraction yields, it is suggested that, for high-coal-rank coals, PO and UF, the breaking of noncovalent bonds such as {pi}-{pi} interactions between aromatic layers and hydrogen bonds is responsible for the extraction yield enhancements. 14 refs., 3 figs., 2 tabs.},
doi = {10.1021/ef060099g},
journal = {Energy and Fuels},
number = 1,
volume = 21,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • The drying kinetics of water from three particle-sized Beulah-Zap lignite coal samples were probed using the differential scanning calorimetry technique at 295 < T < 480 K. The measurements undertaken under flowing N{sub 2} gas environment indicate that water is lost from this coal by two independent but simultaneously operative kinetic mechanisms. Our results suggest that the unimolecular decay kinetics are obeyed by those water molecules which are near the mouths of large pores and/or surround the coal particles. Most of the water, about 80% of the water lost in our experiments, was removed via a 2nd-order diffusion mechanism. Asmore » expected, the desorption activation energies of the 2nd-order diffusion kinetics were much larger than the decay mechanism`s activation energies. Our results also suggest, at least for particle sizes < 841 {mu}m, < 106 {mu}m, and < 37 {mu}m, that the coal particle size has little effect on the desorption activation barriers.« less
  • The reduction of NO emissions from combustion processes has become increasingly important in protecting the world`s environment. It has been shown that Selective Catalytic Reduction (SCR) with ammonia is an effective commercial technique to remove NO{sub x} from combustion flue gas. However, the implementation of this technique is limited by high investment and operating costs, {open_quotes}ammonia slip{close_quotes}, and SO{sub x} poisoning, which motivate the search for alternatives. Carbon (activated carbon or char) is a promising reducing agent for NO{sub x} reduction with many potential advantages, such as low cost, easy availability, high efficiency, simplicity of process, and no secondary pollution.more » Moreover, the heterogeneous reaction of NO with char is very important for the understanding of the formation of NO{sub x} from coal combustion processes. The reaction may significantly destroy the NO{sub x} formed earlier in coal combustion, which partially contributes to low NO emission from fluidized bed combustion. Therefore, the reaction of NO with char is receiving significant attention in the literature. The objectives of this study are to investigate the kinetics of the reaction of NO with Beulah Zap lignite chars, to study the effects of CaO on the kinetics.« less
  • Beulah-Zap lignite and Wyodak-Anderson ([minus]100 and [minus]20 mesh from the Argonne Premium Coal Sample Program) were dried in nitrogen under various conditions of temperature (20--80[degree]C), gas flow rates (20--160 cc/min), and sample sizes (20--160 mg). An equation relating the initial drying rate in the unimolecular mechanism was developed to relate the drying rate and these three variables over the initial 80--85% of the moisture loss for the lignite. The behavior of the Wyodak-Anderson subbituminous coal is very similar to that of the lignite. The nitrogen BET surface area of the subbituminous sample is much larger than the lignite.
  • The lignite drying kinetics follow a unimolecular rate law which is first order in the waste in the sample. There are two segments in the dehydration kinetics plots, and each follows a unimolecular rate law. The first drying segment includes about 80--85% of the water loss. The second drying segment includes includes most of the remaining water and occurs at about half the rate of the first segment. The mechanism is unchanged over the range 20--80{degrees}C. The activation energy for the initial moisture loss is about 8 Kcal/mole. The water jacketed heating system provides superior temperature control. The rate ofmore » drying is sensitive to the gas velocity over the sample. The rate of drying is dependent on the sample size and the sample depth. Rates are generally similar for -20 and -100 mesh samples. The same mechanism is observed for differential scanning calorimetry measurements. X-ray powder diffraction measurements show structural changes during the drying process. Drying improves the oil yield from lignite samples as a result of hydrogenation. 8 refs., 4 figs., 2 tabs.« less
  • Recent results on the kinetics of water's desorption from Beulah-Zap lignite coal, as determined by thermogravimetric analysis (TGA) and the differential scanning calorimetry (DSC) technique were reported. The kinetic analysis of DSC was further complimented by determining the mechanism of air drying of lignite coal with the help of an in-situ Desorption Kinetics via Fourier transform infrared (ISDK-FTIR) technique. 17 refs., 5 figs., 1 tab.