Taner Togrul

The effect of preswelling and/or pretreatment of some Turkish coals on the supercritical fluid extract yield☆

Abstract The effects of preswelling, and/or pretreatment with 1N HCl of four Turkish coals (Bolu-Goynuk, Seyitomer, Tuncbilek and Soma-Merkez) on the supercritical toluene extract yields have been investigated. Methanol, 1,4-dioxane, THF (tetrahydrofuran), pyridine and EDA (ethylenediamine) were used as swelling agents. Solvent swelling and pretreatment with 1N HCl of coals significantly enhanced the liquid yields. The effectiveness of the swelling solvents in enhancing the liquid yield is in the same order as their swelling ratios. Swelling in EDA and pyridine were more effective for the extraction of coals. The highest improved liquid yields in supercritical toluene for each coal was obtained by the combined effects of pretreatment and preswelling of coals. No simple trend in reactivity increment with properties of coals was observed.

The effect of swelling pretreatment on the coal liquefaction in tetralin with microwave energy

Three Turkish coals, a Zonguldak coal and Tunçbilek and Beypazari lignites were used to examine the effect of solvent swelling pretreatment on the solubilization and dissolution behavior. Methanol, THF (tetrahydrofuran) and TBAH (tetrabutylammonium hydroxide) were used as swelling agents. For the investigation of dissolution behavior of coals, the microwave heating period was changed from 10 to 30 min at 5 min intervals. While solvent pretreatment enhanced the THF solubles yields for the Zonguldak coal, solvent treatment decreased the THF solubles yields for the Tunçbilek and Beypazari lignites. The data obtained in this study indicated that the formation mechanism of AS (asphaltenes), PAS (preasphaltenes) and oils depend on the coal and swelling agent type.

The Effect of Moisture on the Liquefaction of Some Turkish Coals in Tetralin with Microwave Energy

The effect of the moisture content of coals, solvent/coal ratio, and the heating period by microwave energy on solubilization of Turkish coals (Bolu-Göynük, Beypazari, Mu < la-Yata < an, Tunçbilek, Aydi n-Yeniçeltek lignites, and Zonguldak coal) in tetralin has been investigated. The yields of tetrahydrofuran (THF) solubles and oils were increased with increasing moisture content of coals. When solvent/coal ratio increased from 2/1 to 4/1, the yield of oils increased. However, the yields of asphaltenes and preasphaltenes decreased. The yields of THF solubles and oils did not change considerably with reaction time. While the yields of asphaltenes and preasphaltenes decreased with reaction time at the value of 2/1 of solvent/coal ratio and increased with reaction time at the value of 4/1 of solvent/coal ratio, the yields are lower than at the value of 2/1 of solvent/coal ratio.

Photocatalytic Dissolution of Two Turkish Lignites in Tetralin: Effects of UV Irradiation, TiO2 and ZnO as Photocatalyst

The effects of ultraviolet (UV) irradiation, photocatalyst, and reaction time on the dissolution of two Turkish lignites (Beypazarı and Tunçbilek lignites) in tetralin have been investigated under ambient conditions. Lignites samples were irradiated in the presence or absence of added photocatalysts (TiO 2 and ZnO) at varying reaction times (1–10 days), constant irradiation power (180 W), and constant solvent/lignite ratio (5/1). The solubility of lignites increased with reaction time under UV light. The liquefaction behaviors of the lignites are different from each other. As the maximum solubility (45%) with Tunçbilek lignite has been achieved at shorter reaction times, it has been reached at longer reaction times for Beypazarı lignite (32%). The solubility values obtained from noncatalytic liquefaction are higher than those obtained from liquefaction with TiO 2 and ZnO.

Reactions of Coal Model Compounds in Tetralin Using Microwave Energy: Effects of Catalysts

Reaction mechanisms of model compounds of coal in tetralin by microwave energy were investigated. Diphenylmethan (DFM), phenyl-methyl ether (anisole), and phenyl-methyl ketone (acetophenon) were chosen as model compounds. Experiments were carried out for 10 minutes of microwave energy and different catalysts were used (pyratol, zeolite, BaCl2, AlNiMo) to find out the distribution of reaction products of the model compounds. GC and GC/MS are used to analyze the reaction products. The main reaction products from DFM and tetralin under microwave radiation with catalysts were ethyl benzene, naphthalene, 2-methyl naphthalene, 3,4-dihydronaphthaleneone, 1-1′-ethyldene 1-benzene, and 1-methyl 4-phenyl methyl benzene. The main reaction products from anisole and tetralin under microwave radiation were ethyl benzene, phenol, methyl phenol, decahydronaphthalene, and tetrahydronaphthalenol. The main reaction products from acetophenon and tetralin under microwave radiation with catalysts were ethyl benzene, methoxy benzene, decahydronaphthalene, naphthalene, tetrahydronaphthalenol, 3,4-dihydronaphthalenone and 2-butene-1-one-1,3 diphenyl. The estimated mechanism of the model compounds with tetralin is compared with the results taken from GC/MS analysis. It is obtained that the results suggested theoretically were similar with the GC/MS results.