Effects of ionic liquid pretreatment on pyrolysis characteristics of a high-sulfur bituminous coal

Liang, Peng; Qin, Xizhuang; Bai, Guangming; Wu, Zexing; Sun, Duixiong; Zhang, Yaqing; Jiao, Tiantian

doi:10.1016/j.fuel.2019.116134

Cited by 16 publications

(10 citation statements)

References 41 publications

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“…As shown in Figure 3 , compared to HBC, hydroxyl absorption peaks (3695 and 3620 cm –1 ) have no obvious change in HBC AC and the swollen coals, which shows that the peak intensity of free hydroxyl in inorganic minerals is weakened after pickling and swelling treatment. 27 Other peak positions of HBC, HBC AC , and the swollen coals are almost the same, indicating that acid-washing treatment removed most inorganic minerals and showed a weak impact on organic functional groups in coal. Absorption peaks at 2920 and 2850 cm –1 belonging to aliphatic −CH 2 did not change, demonstrating that acid pretreatment had almost no effect on the structure of chain aliphatic hydrocarbons.…”

Section: Resultsmentioning

confidence: 86%

Effect of Swelling by Organic Solvent on Structure, Pyrolysis, and Methanol Extraction Performance of Hefeng Bituminous Coal

Wang

et al. 2021

ACS Omega

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N -methyl-2-pyrrolidone (NMP), pyridine (Py), tetrahydrofuran (THF), and tetralin (THN) were used to swell Hefeng acid-washed bituminous coal (HBC AC ). The swelling effect on HBC AC by each solvent is different, among which NMP presented well swelling performance, with a swelling degree of 2.11. FTIR results showed that acid washing and swelling processes presented a marginal effect on HBC, and there was no damage to the macromolecule structure of the coal. TG–DTG profiles of the swollen coals illustrated that the total weight loss of each sample was lower than that of the acid-washing one, while the temperature of the maximum weight loss rate peak was almost unchanged, around 445 °C. Extract yield by methanol followed the order of HBC AC > HBC > HBC AC–NMP (swelled by NMP), showing that acid washing promoted the methanol extraction process, with a higher extract yield of 3.21%, which is twice that of HBC (1.66%).

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Section: Resultsmentioning

confidence: 86%

Effect of Swelling by Organic Solvent on Structure, Pyrolysis, and Methanol Extraction Performance of Hefeng Bituminous Coal

Wang

et al. 2021

ACS Omega

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“…The reason might be that ionic liquid can form new hydrogen bonds with the hydroxyl groups, breaking or weakening the C−O bonds, leading to the reduction of the oxygen-containing functional groups in coal. 26 In addition, there are aromatic CC, asymmetric −CH 3 , −CH 2 , aromatic ring −CH 3 , and symmetric deformation −CH 3 in the range of 1300−1800 cm −1 . Also, the relative content of these functional groups increased, indicating that swelling with ionic liquid can destroy the macromolecular network structure of coal and increase the content of stable small aromatic compounds.…”

Section: Resultsmentioning

confidence: 99%

“…It was discovered that [MTBP][MeSO 4 ] and [BMPYR][CH 3 CO 3 ] showed an obvious destructive effect on the coal structure. Liang et al used four ILs to extract high-sulfur bituminous coal, and a pyrolysis experiment was carried out for the treated coal. Extraction results presented that all of the ILs showed excellent extraction ability for oxygen-containing compounds and sulfur-containing compounds.…”

Section: Introductionmentioning

confidence: 99%

Effect of Swelling with Ionic Liquid on the Molecular Structure and Pyrolysis Behavior of Hefeng Sub-bituminous Coal

et al. 2020

Energy Fuels

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Four ionic liquids, 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]), 1-hexyl-3-methylimidazolium acetate ([HMIM][OAc]), and 1-octyl-3-methylimidazolium acetate ([OMIM]-[OAc]), were used to swell Hefeng sub-bituminous coal. The effect of swelling on the molecular structure and pyrolysis behavior of the coal was investigated by swelling degree Q, SEM, FTIR, and TG-DTG characterizations. Results showed that swelling degree by different ionic liquid was in the range of 2.0−2.4, with a higher degree of 2.4 for the coal sample swelled by [OMIM][OAc]. The swelling process could destroy the surface morphology and pore structure of the coal and increase and loosen the sample's pore channel. The results of the FTIR analysis revealed that swelling can destroy hydrogen bonds in coal, reduce the relative content of oxygen-containing functional groups, and might increase the relative amount of low-molecular-weight organics. TG-DTG profiles proposed that swelling with ionic liquid could promote weight loss and pyrolysis conversion of the coal and significantly changed its pyrolysis behavior at the temperature of 180−350 °C. The Coats−Redfern results presented that swelling increased the pyrolysis activation energy of the coal at 180−350 °C, while the energy was decreased at 350−550 °C.

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“…The limitation of the method is that the efficiency of the method largely depends on the sulfur form in the coal, the method or chemical reagent, and the conditions used. Therefore, the coal desulfurization cost is high, the process is complex, and has an effect on the quality of coal. − Compared to the two aforementioned methods, microwave desulfurization has received many researchers’ attention for its excellent environmental performance and minimal coal structure damage. A growing body of studies has suggested that microwaves combined with chemical reagents that have good dielectric properties can improve the microwave energy absorption efficiency and safely remove sulfur from coal under lower temperature conditions. − …”

Section: Introductionmentioning

confidence: 99%

Combustion Kinetics of Coal Treated by Microwave Irradiation Combined with Hydrochloric Acid Pickling

et al. 2021

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The desulfurization efficiency, combustion properties, combustion kinetics, and structural changes of Kentucky coal under microwave irradiation (MI) combined with hydrochloric acid solution pickling were investigated and compared using a thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer. The results show that the desulfurization rate increases with the concentration of hydrochloric acid solution. The introduction of MI can effectively improve the desulfurization efficiency. After desulfurization, the ignition temperature and burnout temperature of coal samples increase, the combustion index decreases, and the combustion performance deteriorates. The maximum weight loss rate decreases with the increase of the concentration of hydrochloric acid solution, and the activation energy of the coal sample after microwave treatment increases, and the reaction difficulty increases. The infrared analysis results show that MI and hydrochloric acid pickling treatment have little effect on the functional group structure of coal samples.

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Effects of ionic liquid pretreatment on pyrolysis characteristics of a high-sulfur bituminous coal

Cited by 16 publications

References 41 publications

Effect of Swelling by Organic Solvent on Structure, Pyrolysis, and Methanol Extraction Performance of Hefeng Bituminous Coal

Effect of Swelling by Organic Solvent on Structure, Pyrolysis, and Methanol Extraction Performance of Hefeng Bituminous Coal

Effect of Swelling with Ionic Liquid on the Molecular Structure and Pyrolysis Behavior of Hefeng Sub-bituminous Coal

Combustion Kinetics of Coal Treated by Microwave Irradiation Combined with Hydrochloric Acid Pickling

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