Viscosity of brown coal-solvent slurry

Okuma, Osamu; Mae, Kazuhiro; Yanai, Shunichi; Nakako, Yukio

doi:10.1016/0378-3820(89)90062-3

Cited by 8 publications

(6 citation statements)

References 12 publications

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“…The removal of the oxygen functional groups by HTT shown in Figures and is also expected to contribute to the reduction of the slurry viscosity to some extent, especially when the solvent contains polar components, as reported by Okuma et al In the BCL process, the DW/S prepared by the same procedure as in this work was intended to be supplied to the PH section. Then, the coal concentration in the DW/S could not exceed 28 wt % because of high viscosity caused by the penetration of the solvent into the pores of the coal . On the other hand, the coal concentration in HTT(320)-DW/S reached as high as 40 wt % at a viscosity as low as 320 mPa s. A high coal concentration in the slurry contributes to the increase of the space time yield of the liquefaction reactor.…”

Section: Resultsmentioning

confidence: 56%

“…The viscosities of the slurries prepared were measured using a rotational viscometer (Couette rheomater, RM30) equipped with a double-cylinder system. 13 3. RESULTS AND DISCUSSION 3.1.…”

Section: Methodsmentioning

confidence: 99%

“…In the BCL process, pulverized raw coal is dewatered in a solvent by the so-called slurry-dewatering system and then hydroliquefied at high temperature (<450 °C) and high pressure (<15 MPa) in the presence of a catalyst. The slurry dewatering was employed because of its high thermal efficiency. , Because the coal is supplied as a coal–solvent slurry to the liquefaction reactor in the primary hydrogenation (PH) section, it is a key factor to increase the coal concentration of the coal–solvent slurry for increasing the space time yield of the reactor.…”

Section: Introductionmentioning

confidence: 99%

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Hydrothermal Treatment of Brown Coal To Improve the Space Time Yield of a Direct Liquefaction Reactor

Inoue¹,

Okuma²,

Masuda³

et al. 2012

Energy Fuels

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The possibility of hydrothermal treatment (HTT) of brown coal at 200−350 °C was examined as a pretreatment method for improving the space time yield of a Victorian brown coal liquefaction reactor. Main reactions occurring during HTT below 350 °C were decarboxylation and dehydration, by which most of carboxylic groups were decomposed. Sodium and chlorine in the brown coal were almost completely removed below 250 and 300 °C, respectively, during HTT. Around 20−30% of Ca and Mg in the brown coal was also removed by HTT below 350 °C. The viscosity of the coal−solvent slurry prepared from a HTT coal was less than 1 / 10 of the viscosity of the coal−solvent slurry prepared from a just dewatered coal. This enabled the increase of the coal concentration of the coal−solvent slurry from 28 to 40 wt %. The significant increase of the coal concentration of the coal−solvent slurry prepared from the HTT coal was found to be realized mainly by the decrease of the pore volume of the coal particles through HTT. These results suggest that HTT will be a pretreatment method effective not only to increase the space time yield but to suppress the scale formation of the brown coal liquefaction process.

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Section: Resultsmentioning

confidence: 56%

“…The viscosities of the slurries prepared were measured using a rotational viscometer (Couette rheomater, RM30) equipped with a double-cylinder system. 13 3. RESULTS AND DISCUSSION 3.1.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydrothermal Treatment of Brown Coal To Improve the Space Time Yield of a Direct Liquefaction Reactor

Inoue¹,

Okuma²,

Masuda³

et al. 2012

Energy Fuels

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“…1109 kJ (Kanda et al 2008), almost one-half that required by conventional heating methods (ca. 2100 kJ) (Anderson et al 1991;Couch 1990;Deguchi et al 1996;Iwai et al 1998;Okuma et al 1986Okuma et al , 1989aShigehisa et al 2000;Simmons 1986;Terunuma et al 1986;U.S. DOE 1996U.S.…”

Section: Principle Of Dme Dewatering Technologymentioning

confidence: 99%

Super-Energy-Saving Dewatering Method for High-Specific-Surface-Area Fuels by Using Dimethyl Ether

Kanda

2008

Adsorption Science & Technology

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There is a growing need for the economical dewatering of highspecific-surface-area fuels containing large amounts of water, such as coal and sewage sludge. The principle underlying conventional dewatering methods is evaporation of the water content by heating the fuels to a high temperature, but this approach consumes a considerable amount of energy. The Central Research Institute of the Electric Power Industry (CRIEPI) has developed a method for the extraction of this water through the use of dimethyl ether (DME), which liquefies at ordinary temperatures under the influence of a slight pressure. In this method, the water content in the fuel is extracted into the liquefied DME for separation from the fuel. After dewatering, the DME is depressurised, and subsequently vaporised, thereby leaving the separated water. Dewatering with an input energy of only 1109 kJ/kg water under ordinary conditions has been demonstrated theoretically.

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“…However, as demonstrated by Miura et al (2002), the current dewatering techniques consume considerable energy or require costly chemicals. Classical techniques involving high energy consumption include dewatering using supercritical CO 2 (Iwai et al 1998) as well as the following methods: flash dry, steam tube drying (STD), steam fluidized bed drying (SFBD), mechanical thermal expression (MTE), hydrothermal drying (HTD), the Koppelman process (Kfuel) (Couch 1990), upgraded of brown coal method (UBC) (Simmons 1986;Okuma et al, 1986Okuma et al, , 1989aOkuma et al, , 1989bYanagi et al 1994;Deguchi et al 1996;Terunuma et al 1986;Yosumuro et al 2000;Shigehisa et al 2000), the Syncoal technique (U.S. DOE 1996), hot water dewatering (HWD) (Anderson et al 1990), and the Encoal technique (U.S. DOE 1997).…”

Section: Introductionmentioning

confidence: 99%

Energy-saving drying technology for porous media using liquefied DME gas

2008

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Process design and energy requirement for a practical plant are investigated for an energy-saving drying (dewatering) process invented by the authors in 2002 for highmoisture porous materials. The basic concept of the process involves the extraction of water from a high-moisture porous material by bringing it in physical contact with liquefied dimethyl ether (DME) at room temperature. Water content of DME asymptotically increases to the saturation value and the high-moisture porous material is dried almost perfectly. DME from the DME-water mixture is vaporized by decompression. DME and water are separated by flash distillation. DME vapor is compressed and cooled in a heat exchanger, and the latent heat of condensation is reused to vaporize the DME in the heat exchanger. Multistage compression and multistage flash distillation are employed. After compression, the temperature of DME is less than 50°C. Because specific heat ratio of DME is only 1.11, the energy consumption of the compressor is reduced. Considering the adiabatic efficiency of the compressor and the net thermal efficiency, the total energy for dewatering is about 1100 kJ per 1-kg-water-content of the material being dewatered This process has significant potential and is compact than the existing dewatering processes.

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Viscosity of brown coal-solvent slurry

Cited by 8 publications

References 12 publications

Hydrothermal Treatment of Brown Coal To Improve the Space Time Yield of a Direct Liquefaction Reactor

Hydrothermal Treatment of Brown Coal To Improve the Space Time Yield of a Direct Liquefaction Reactor

Super-Energy-Saving Dewatering Method for High-Specific-Surface-Area Fuels by Using Dimethyl Ether

Energy-saving drying technology for porous media using liquefied DME gas

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