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Liang-shih Fan - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic and experimental analyses of the three stage calcium looping process
    Industrial & Engineering Chemistry Research, 2010
    Co-Authors: Shwetha Ramkumar, Liang-shih Fan
    Abstract:

    Clean-Coal technologies that include carbon dioxide and sulfur capture during the production of electric power, liquid fuels, and hydrogen represent a major thrust area. The calcium looping process...

  • Clean Coal conversion processes progress and challenges
    Energy and Environmental Science, 2008
    Co-Authors: Liang-shih Fan
    Abstract:

    Although the processing of Coal is an ancient problem and has been practiced for centuries, the constraints posed on today's Coal conversion processes are unprecedented, and utmost innovations are required for finding the solution to the problem.With a strong demand for an affordable energy supply which is compounded by the urgent need for a CO2 emission control, the Clean and efficient utilization of Coal presents both a challenge and an opportunity to the current global R&D efforts in this area. This paper provides a historical perspective on the utilization of Coal as an energy source as well as describing the progress and challenges and the future prospect of Clean Coal conversion processes. It provides background on the historical utilization of Coal as an energy source, along with particular emphasis on the constraints in current Coal conversion technologies. It addresses the energy conversion efficiencies for current Coal combustion and gasification processes and for the membrane and looping based novel processes which are currently under development at various stages of testing. The control technologies for pollutants including CO2 in flue gas or syngas are also discussed. The Coal conversion process efficiencies under a CO2 constrained environment are illustrated based on data and ASPEN Plus® simulations. The challenges for future R&D efforts in novel Coal conversion process development are also presented.

Karen M Steel - One of the best experts on this subject based on the ideXlab platform.

  • combustion behaviour of ultra Clean Coal obtained by chemical demineralisation
    Fuel, 2003
    Co-Authors: F Rubiera, Karen M Steel, A Arenillas, B Arias, J J Pis, Isabel Suarezruiz, John W Patrick
    Abstract:

    The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new Coal Cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from Coal either by physical or chemical methods can be annulled if poor Coal combustibility characteristics are attained. In this work a high volatile bituminous Coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the Clean Coal was reduced to 0.3%. The original and treated Coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system. Comparison of the combustion behaviour and pollutant emissions of both Coals was conducted in a drop tube furnace operating at 1000 °C. The results of this work indicate that the char obtained from the chemically treated Coal presents very different structure, morphology and reactivity behaviour than the char from the original Coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised Coal.

  • the production of ultra Clean Coal by chemical demineralisation
    Fuel, 2001
    Co-Authors: Karen M Steel, John W Patrick
    Abstract:

    A high-volatile UK Coal, with a particle size of < 500 mum, an ash content of approximately 7.9% by weight and a sulphur content of 2.6% by weight, was treated with aqueous HF followed by aqueous HNO3. The reaction residence time and temperature for both treatments were 3 h and 65 degreesC, respectively. HF reduces the ash content to approximately 2.6% by weight. The remaining ash largely consists of fluoride compounds such as AlF3, NaAlF4, CaF2 and MgF2, Which form during leaching, and pyrite (FeS2), which does not react with HF. HNO3 then further reduces the ash content to approximately 0.6% by weight, by dissolving fluoride compounds and the Fe present as FeS2. The remaining ash consists largely of unreacted FeS2, which is encapsulated in the Coal structure. This investigation also showed that HNO3 only reacts with FeS2 above a particular HNO3 Concentration, which suggests that it is consumed preferentially, and to a certain extent, with the organic Coal structure. The final sulphur content following treatment with HF and HNO3 was 1.4% by weight.

  • production of ultra Clean Coal part i dissolution behaviour of mineral matter in black Coal toward hydrochloric and hydrofluoric acids
    Fuel Processing Technology, 2001
    Co-Authors: Karen M Steel, John Besida, T A Odonnell, D G Wood
    Abstract:

    The mineral matter in an Australian black Coal has been isolated using a low-temperature ashing (LTA) procedure. This LTA procedure is a modification of the Australian Standard for LTA at 370 degrees C, and alleviates adverse effects to thr: minerals caused by the heat of combustion. The leaching behaviour of the mineral matter towards aqueous HCl and hydrofluoric acid (HF) is presented. HCl can dissolve simple compounds such as phosphates and carbonates, yet it cannot completely dissolve the clays. HF resets with almost every mineral in the mineral matter, except pyrite, and most of the reaction products are water soluble. However, at HF concentrations greater than that required to dissolve the aluminosilicate compounds in the mineral matter, insoluble compounds form. These compounds include CaF2, MgF2 and a compound containing Na, which is believed to be NaAlF4. It is proposed that HF reacts preferentially with the aluminosilicates in the mineral matter to form largely AlF2+, AlF3 and SiF4, and that the concentrations of free fluoride (F-) and AlF4- are not high enough to complex cations such as Ca2+, Mg2+ and Na+. When the mineral matter is treated with HF concentrations greater than that required to dissolve all of the aluminosilicates, AlF3, AlF4- and SiF62- form, the concentration of F- is high enough to complex Ca2+ and Mg2+ and form insoluble CaF2 and MgF2, and the concentration of AlF4- is high enough to complex Na+ and form insoluble NaAlF4. This work has application toward the development of a process for producing Ultra Clean Coal with less than 0.1% by weight mineral matter. (C) 2001 Elsevier Science B.V. All rights reserved.

  • production of ultra Clean Coal part ii ionic equilibria in solution when mineral matter from black Coal is treated with aqueous hydrofluoric acid
    Fuel Processing Technology, 2001
    Co-Authors: Karen M Steel, John Besida, T A Odonnell, D G Wood
    Abstract:

    A model fur determination of the concentration of fluoride complexed aluminium and silicon species, free fluoride (F-), II+ ions and molecular HF in solution when aluminosilicate compounds are treated with aqueous HF is presented. The model elucidates chemical mechanisms governing both the dissolution behaviour of the mineral matter in Coal towards aqueous HF, and the unwanted precipitation of various fluoride compounds, such as CaF2, MgF2 and NaAIF(4). The controlling parameter for the precipitation of fluoride compounds is the free F- concentration in solution. The model has application toward the development of chemical strategies for dissolving virtually all of the mineral matter from Coal and avoiding the unwanted precipitation of fluoride compounds. The model also has application toward the development of a strategy for recovering fluoride from spent leaching solutions. Ultimately, this work will assist in the development of a process for the production of Ultra Clean Coal (UCC) containing less than 0.1% by weight mineral matter.

Ningning Zhang - One of the best experts on this subject based on the ideXlab platform.

  • parent alkylated oxygenated and nitro polycyclic aromatic hydrocarbons from raw Coal chunks and Clean Coal combustion emission factors source profiles and health risks
    Science of The Total Environment, 2020
    Co-Authors: Yue Zhang, Zhenxing Shen, Jian Sun, Leiming Zhang, Bin Zhang, Tian Zhang, Jinhui Wang, Pingping Liu, Ningning Zhang
    Abstract:

    Abstract Residential Coals are still inevitable using in developing areas in China. Clean Coal briquettes, normally using alkaline substance such as lime or red mud (RM) as the additive, were helpful in pollution emission reduction even without changes of stoves. Studies of atmospheric polycyclic aromatic hydrocarbons (PAHs) emission characteristics from RM clear Coal combustion were limited. In this study, emission factors (EFs), sources profiles, and health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were investigated for raw Coal chunks and Clean Coal (with red mud) through combustion experiments. EFs of total PAHs were found to be 160.1 ± 100.9 mg·kg−1 and 19.4 ± 6.1 mg·kg−1 for bituminous and anthracite raw Coal chunks (B-C and A-C), respectively. EFs values were highest for parent PAHs (p-PAHs), followed by oxygenated PAHs (o-PAHs), alkylated PAHs (a-PAHs), and nitro PAHs (n-PAHs). EFs of p-PAHs account for 80% and 52% of total PAHs emissions for B-C and A-C, respectively, while those for o-PAHs are 22.9% and 44.9%, demonstrating residential Coal combustion as a significant primary source for p-PAHs and o-PAHs. Clean Coals were developed through cold-press technology with red mud (RM) as additive, and Clean Coals with RM contents of 10% are referred to as B-10% (bituminous) and A-10% (anthracite). Compared to raw Coals chunks, EFs were reduced from 128.1, 2.5, 29.3 mg·kg−1 and 161.8 μg·kg−1 to 83.5, 1.3, 16.4 mg·kg−1 and 102.2 μg·kg−1 by B-10%, and from 10.1, 0.6, 8.7 mg·kg−1 and 20.6 μg·kg−1 to 11.9, 0.2, 2.4 mg·kg−1 and 15.3 μg·kg−1 by A-10% for p-PAHs, o-PAHs, a-PAHs and n-PAHs, respectively. Diagnostic ratios of 5-Nitroacenaphthene / Acenaphthene (0.02–0.05 for Coal, 0.0002 for biomass) can be used to separate residential Coal and biomass burning in source analysis. When B-C was replaced by B-10%, both noncancer (0.58 to 0.33 for male, 1.65 to 0.95 for female in hazard quotient) and cancer risks (5.68 × 10−4 to 2.73 × 10−4 for male, 2.63 × 10−3 to 1.27 × 10−3 for female) can be reduced. o-PAHs should be paid more attention because of its high cancer risks caused by 6H-Benzo(C,D)Pyrene-6-One (1.74 × 10−5 for male, 8.07 × 10−5 for female), which are even more than the total risks caused by n-PAHs (3.59 × 10−7 for male, 1.66 × 10−6 for female). Results from this study highlighted the environment and health effects of PAHs originated from residential Coal combustion, and proposed an effective way by using Clean Coal to alleviate the associated negative impacts.

D G Wood - One of the best experts on this subject based on the ideXlab platform.

  • production of ultra Clean Coal part i dissolution behaviour of mineral matter in black Coal toward hydrochloric and hydrofluoric acids
    Fuel Processing Technology, 2001
    Co-Authors: Karen M Steel, John Besida, T A Odonnell, D G Wood
    Abstract:

    The mineral matter in an Australian black Coal has been isolated using a low-temperature ashing (LTA) procedure. This LTA procedure is a modification of the Australian Standard for LTA at 370 degrees C, and alleviates adverse effects to thr: minerals caused by the heat of combustion. The leaching behaviour of the mineral matter towards aqueous HCl and hydrofluoric acid (HF) is presented. HCl can dissolve simple compounds such as phosphates and carbonates, yet it cannot completely dissolve the clays. HF resets with almost every mineral in the mineral matter, except pyrite, and most of the reaction products are water soluble. However, at HF concentrations greater than that required to dissolve the aluminosilicate compounds in the mineral matter, insoluble compounds form. These compounds include CaF2, MgF2 and a compound containing Na, which is believed to be NaAlF4. It is proposed that HF reacts preferentially with the aluminosilicates in the mineral matter to form largely AlF2+, AlF3 and SiF4, and that the concentrations of free fluoride (F-) and AlF4- are not high enough to complex cations such as Ca2+, Mg2+ and Na+. When the mineral matter is treated with HF concentrations greater than that required to dissolve all of the aluminosilicates, AlF3, AlF4- and SiF62- form, the concentration of F- is high enough to complex Ca2+ and Mg2+ and form insoluble CaF2 and MgF2, and the concentration of AlF4- is high enough to complex Na+ and form insoluble NaAlF4. This work has application toward the development of a process for producing Ultra Clean Coal with less than 0.1% by weight mineral matter. (C) 2001 Elsevier Science B.V. All rights reserved.

  • production of ultra Clean Coal part ii ionic equilibria in solution when mineral matter from black Coal is treated with aqueous hydrofluoric acid
    Fuel Processing Technology, 2001
    Co-Authors: Karen M Steel, John Besida, T A Odonnell, D G Wood
    Abstract:

    A model fur determination of the concentration of fluoride complexed aluminium and silicon species, free fluoride (F-), II+ ions and molecular HF in solution when aluminosilicate compounds are treated with aqueous HF is presented. The model elucidates chemical mechanisms governing both the dissolution behaviour of the mineral matter in Coal towards aqueous HF, and the unwanted precipitation of various fluoride compounds, such as CaF2, MgF2 and NaAIF(4). The controlling parameter for the precipitation of fluoride compounds is the free F- concentration in solution. The model has application toward the development of chemical strategies for dissolving virtually all of the mineral matter from Coal and avoiding the unwanted precipitation of fluoride compounds. The model also has application toward the development of a strategy for recovering fluoride from spent leaching solutions. Ultimately, this work will assist in the development of a process for the production of Ultra Clean Coal (UCC) containing less than 0.1% by weight mineral matter.

Shwetha Ramkumar - One of the best experts on this subject based on the ideXlab platform.