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    Co-liquefaction of Elbistan Lignite and Biomass. Part I: The Effect of the Process Parameters on the Conversion of Liquefaction Products
    (Taylor & Francis Inc, 2010) Karaca, H.; Koyunoglu, C.
    In this study, the liquefaction of Elbistan lignite and the co-liquefaction of Elbistan lignite with the biomass were examined. The biomass type used in this study consists of waste plastic, waste paper, waste mud, and molasses. The dissolution reactions were carried out in tetralin at 350-425 degrees C under nitrogen atmosphere. Mo(CO)(6), Cr(CO)(6), Fe2O3, and MoO3 were used as the added catalysts. The particle size ranged from 0.25 mm to 1.5 mm, the isothermal extraction periods ranged from 30 to 150 min, and the solvent/lignite ratio ranged from 1/1 to 9/1. The results indicated that total conversion and oil C gas conversion obtained during the liquefaction largely changed according to catalyst type, biomass type, and reaction temperature. It is understood that other process parameters, such as particle size and solvent/solid ratio, did not have any important effects. According to the obtained results, optimum process parameters were determined as particle size of 1.5 mm, solvent/solid ratio of 3/1, reaction time of 90 min, and reaction temperature of 400 degrees C. Fe2O3 was selected as the most suitable catalyst type and waste paper as biomass type. In order to reduce liquefaction cost in liquefaction operations, results of the experimental studies showed that using coal + biomass instead of coal, nitrogen instead of hydrogen, and recycled solvent instead of fresh solvent would be more suitable.
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    The Co-liquefaction of Elbistan Lignite and Biomass. Part II: The Characterization of Liquefaction Products
    (Taylor & Francis Inc, 2010) Karaca, H.; Koyunoglu, C.
    This study examines the effects of various process parameters regarding separately and co-liquefaction in a nitrogen gas medium under catalytic and non-catalytic conditions of Elbistan lignite and various biomass samples, the direct use of which is inconvenient both economically and ecologically. According to the obtained results, the optimum process parameters are as follows: The particle size is 1.5 mm, liquid/solid ratio is 3/1, reaction time is 90 min, and reaction temperature is 400 degrees C. Fe2O3 has been selected as the most suitable catalyst type and waste paper as the most suitable biomass type. At 3/1 liquid/solid ratio, as a result of the liquefaction studies, which are made through using fresh and recycled solvent, the obtained total conversions are 90.2 and 88.4%, oil + gas conversions are 59.3 and 57.6%. Elemental analyses have been made in order to gain information on the structure of the preasphaltene and chars, which are obtained as a result of the liquefaction of Elbistan lignite separately and together with paper under catalytic conditions. According to the results of the elemental analysis, chars and preasphaltenes may not be used as fuel. However, as preasphaltenes have high content of both carbon and hydrogen, their re-liquefaction under catalytic and non-catalytic conditions separately or together with the biomass, and the co-liquefaction of the char with the biomass or burning it in a fluidized bed may be recommended. According to the results of gas chromatography/mass spectrometry analyses of the oils obtained as a result of liquefaction, the oils basically consist of various components, such as naphthalene and its derivatives, tetraline and derivatives, indene, butylated-hydroxytoluen, binaphtalene, and indole.
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    Co-liquefaction of the Elbistan Lignite and Poplar Sawdust. Part I: The Effect of the Liquefaction Parameters
    (Taylor & Francis Inc, 2009) Karaca, H.; Acar, M.; Yilmaz, M.; Keklik, I.
    In this study, the liquefaction of Elbistan lignite and poplar sawdust, and the co-liquefaction of the Elbistan lignite and the poplar sawdust in an inert atmosphere and in non-catalytic conditions have been examined. Also, the effects of solvent/coal ratio and stirring speed on the total conversion derived as the result of the liquefaction process was attempted to be determined. Based on the results, although the effects of the solvent/coal ratio and the stirring speed on total conversion are similar for both the Elbistan lignite and the poplar sawdust, it was also noted that, under similar conditions, the conversion for the poplar sawdust was higher, as compared to the conversion of the Elbistan lignite. As the result of the liquefaction of Elbistan lignite and poplar sawdust under inert atmospheric conditions, the total conversion was increased partially, depending on both solvent/coal ratio and the speed of stirring. However, it was also noted that the total conversion did not change to a significant extent in high solvent/coal ratios and in stirring speed. As the result of the co-liquefaction of the Elbistan lignite and poplar sawdust under inert atmospheric conditions, total conversion was increased, based on the solvent/coal ratio. However, as in the case of the liquefaction of Elbistan lignite and poplar sawdust, it was noted that the high solvent/coal ratios (i.e., solvent/coal ratios of higher than 2/1) did not have a significant effect on the total conversion that was derived as the result of the co-liquefaction of the Elbistan lignite and poplar sawdust.