The advantages of vacuum-treatment in the thermal upgrading of low-rank coals on the improvement of dewatering and devolatilization

Mahidin, Mahidin; Ogaki, Yuji; Usui, Hiromoto; Okuma, Osamu

doi:10.1016/s0378-3820(03)00052-3

Cited by 50 publications

(34 citation statements)

References 23 publications

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“…The porous structure of lignite mainly comprises of mesopores and macropores 24) and the similar result that micropores of the lignite can be negligibly was found by adsorptiondesorption isotherms of N 2 at 77 K (not shown). These suggest that EWC is greatly controlled by mesopores and macropores in porous structure aspect, which is one of the most important factors that in uence EWC.…”

Section: Mechanism Of Ewc In Lignite At Various Rhssupporting

confidence: 70%

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

et al. 2016

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Measurements of equilibrium water contents (EWCs) in samples obtained from hydrothermal treatment (HT) and HT coupled with mechanical compression (HT-MC) were undertaken across a range of relative humidities (RHs) to investigate the performance of EWC and its mechanism. The changes in the concentrations of carboxyl groups and mesopore volume were measured by an improved barium ion exchange and N 2 adsorption-desorption isotherms methods, respectively. The results showed that EWCs decreased with progressively severe HT and HT-MC conditions and EWCs of HT-MC samples were lower than those of HT samples, indicating that HT and HT-MC can upgrade lignite by reducing water loading capacity and HT-MC was better than HT. At low RHs (RH ≤ 10%), the factor that controls EWC is water moleculesactive sites interactions and one to two water molecules are associated with each carboxyl group, while at medium RHs (10 < RH ≤ 92%) the amount of monolayer water and mesopore volume gain in signi cance and ca. two multilayer water molecules are bound to each monolayer water molecule. At high RHs (RH > 92%), EWC is determined by comprehensive factors such as macropores and cracks. Furthermore, EWC can be either higher or lower than residual water content (RWC) based on the RH within a threshold residual water level (ca. 5 to 16%). EWC was generally higher than RWC below a RWC of ca. 5% and the opposite relationship was observed for samples with RWC above ca. 16%. These provide information for the operation of lignite dewatering technique, the control of its water re-adsorption, and storage.

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Section: Mechanism Of Ewc In Lignite At Various Rhssupporting

confidence: 70%

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

et al. 2016

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“…In our previous studies, devolatilization occurred at a very low temperature (200°C) for low-rank coal drying. However, the drying process was done in a vacuum state of 160 Torr [31,32]. Since the lowest temperature observed in this investigation was 300°C, it is expected that devolatilization and char burning had partly taken place.…”

Section: Effect Of Temperature and Ca/s Ratio On The So 2 Profile Witmentioning

confidence: 88%

Sulfur Removal in Bio-Briquette Combustion Using Seashell Waste Adsorbent at Low Temperature

Mahidin

Gani

Muslim

et al. 2016

J. Eng. Technol. Sci.

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Abstract. Presently, biomass is mostly utilized as co-fuel in coal combustion in view of energy diversification and emission reduction. However, since the coal content of bio-briquettes is high (up to 80% in this study), gas emissions such as those of SO x still occur. Therefore, the introduction of SO 2 adsorbent is common in coal briquette or bio-briquette combustion. A calcium-based material is usually used for this goal. The aim of this study was to observe the effects of desulfurization temperature and Ca/S ratio (Ca = calcium content in adsorbent; S = sulfur content in coal and biomass) on desulfurization efficiency and kinetics. The ratio of coal to biomass (palm kernel shell/PKS) was fixed at 90:10 (wt/wt) and the ratios of Ca to S were varied at 1:1, 1.25:1, 1.5:1, 1.75:1 and 2:1. The mixtures of coal, PKS and adsorbent were briquetted at a molding pressure of 6 ton/cm 2 with Jatropha curcas seeds and starch mixture as binding agents. Desulfurization was performed within a temperature range of 300 to 500°C for 720 seconds at an airflow rate of 1.2 L/min. The results showed that the highest desulfurization efficiency (90.6%) was associated with the Ca/S ratio of 2:1 and temperature of 400°C. Moreover, the highest reaction rate constant of desulfurization was 0.280 min -1 .

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“…From the DTA-TG curves, a number of combustion parameters can be derived, such as, ignition temperature (T ig ), maximum combustion rate temperature (T max ), maximum combustion rate (R max ) and char burn-out temperature (T bo ) [9][10][11]. Ignition temperature (T ig ) is an important characteristic of peat fuel combustion, especially for raw peat due to its high intensity of spontaneous combustion [4]. The ignition temperature is taken as the extrapolated onset temperature of the first peak of the DTA curve, which also corresponds to the temperature at which the TG curve departs from the base line.…”

Section: Products Properties: Tg-dta Examination Resultsmentioning

confidence: 99%

“…The maximum experimental temperature was 800 °C. A number of parameters were derived from the DTA-TG curves, which are defined by [4] The primary components and the chemical structure of the raw peat and the solid product were further analyzed by Fourier transform infrared spectroscopy (FTIR) (JASCO 670 Plus) using the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique and the JASCO IR Mentor Pro 6.5 software for spectral analysis [3].…”

Section: Discussionmentioning

confidence: 99%

Physicochemical properties of hydrothermally treated peat fuel obtained from Mempawah-West Kalimantan: influence of hydrophilicity index on carbon aromaticity and combustibility

Mursito

Hirajima

Listiyowati

2018

IOP Conf. Ser.: Earth Environ. Sci.

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The advantages of vacuum-treatment in the thermal upgrading of low-rank coals on the improvement of dewatering and devolatilization

Cited by 50 publications

References 23 publications

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

Sulfur Removal in Bio-Briquette Combustion Using Seashell Waste Adsorbent at Low Temperature

Physicochemical properties of hydrothermally treated peat fuel obtained from Mempawah-West Kalimantan: influence of hydrophilicity index on carbon aromaticity and combustibility

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