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Mineral presents an important effect on the structure and reactivity of coal, and deashing pretreatment is one of the most effective ways to remove mineral from coal. However, deashing pretreatment can change the molecular structure of coal, thus affecting its clean and efficient utilization. To understand the effect of deashing on the molecular structure of Hefeng coal (HF) and its liquefaction residue (LR), HF, LR, Hefeng deashed coal (HFAC), and its liquefaction residue (LRAC) were investigated by Fourier transform infrared spectroscopy (FTIR). Results showed that the deashing treatment could destroy the chemical structure of the coal, while the removal of mineral is not conducive to the liquefaction process of HF. After deashing treatment, the relative content of OH–π hydrogen bonds and self-associated –OH hydrogen bonds declined by 22.40% and 32.10%, respectively. For the aliphatic structure, the content of aliphatic –CH2 changed obviously, among which the asymmetric –CH2 reduced by 12.23%, while the symmetric –CH2 added by 15.27%. For the oxygen-containing functional groups, the carboxyl group increased by 118.95%, and the relative content of C–O group reduced by 49.35%. The 5-substitutions of benzene ring almost disappeared after the deashing process, and the 2-substitutions of benzene ring remarkably increased by 148%, which are predominant in the aromatic structure. After liquefaction, compared to HF, the characteristic peaks ascribed to hydroxyl structure, aliphatic structure, and C=O in LR almost vanished, while the intensity of these peaks in LRAC was stronger than that in LR. The relative content of 5- and 4-substitutions of benzene rings dropped by 33.9%, while the content of 2- and 3-substitutions of benzene rings were increased by 45.47% in LRAC. Structural parameters from functional groups indicated that the length of aliphatic chain was shortened in HFAC and LRAC, and the aromaticity and the condensation degree of aromatic ring were decreased. [ABSTRACT FROM AUTHOR]

Liquefaction residue of Heishan bituminous coal (HLR) was subject to two hydroconversion reactions under 5 MPa initial pressure of hydrogen at 300°C for 3 h, without catalyst and with acid supported catalyst (ASC), respectively. The reaction products were analyzed with gas chromatography/mass spectrometer (GC/MS). The results show that 222 organic compounds were detected totally in the products and they can be divided into alkanes, aromatic hydrocarbons (AHCs), phenols, ketones, ethers, and other species (OSs). The yield of hydroconversion over the ASC is much higher than that without catalyst. The most abundant products are aromatic hydrocarbons in the reaction products from both catalytic and noncatalytic reactions of HLR. The yield of aromatic hydrocarbons in the reaction product from hydroconversion with the ACS is considerably higher than that from hydroconversion without a catalyst. [ABSTRACT FROM AUTHOR]

Abstract: The behavior of liquefaction of Shengli (SL) lignite with NaOH–methanol was studied. Based on high content of water in lignite and the economy of the process (amounts of NaOH used), the effects of NaOH concentration, methanol content and water content on the liquefaction behavior of SL lignite were preliminarily investigated. The results show that SL lignite has a good reaction activity, and its conversion and product yield reach 98% and 99% at 300°C for 1h respectively, when the ratio of SL lignite, NaOH and methanol is for 1g:1g:10ml. NaOH participates in the reaction. The increase of the amount of NaOH significantly increases the amount of tetrahydrofuran soluble (THFS) fraction. Methanol plays a promotion role in the liquefaction, which makes the product yield increase for about 16–23%. Water content has little effect on the SL lignite conversion, product yield and the product distribution. Solvent-extraction components of liquefaction products of SL lignite with NaOH–methanol are mainly THFS, toluene soluble (TS), hexane soluble (HS) and water soluble fractions (WS). The FTIR analyses of solvent-extraction components show that all of the fractions contain OH group, aromatic structure, carbonyl group and aromatic ether oxygen group. [Copyright &y& Elsevier]

• Solid superacid catalysts with different supports were prepared for direct coal liquefaction. • TFMSA/ZrO 2 presented high catalytic activity for direct coal liquefaction. Highly active, recyclable, and reusable supported super-acid catalyst is of great significance for improving coal liquefaction performance and liquefaction conditions and realizing comprehensive utilization of coal resources. Solid super-acid catalysts were prepared by impregnation method with trifluoromethanesulfonic acid (TFMSA) supported on different carriers (ZrO 2 , Al 2 O 3 , SiO 2 , and ZSM-5). Hefeng sub-bituminous coal (HFSB) was used as raw material to investigate the liquefaction effect of the catalysts. Composition, structure, acidity property of the catalysts were analyzed by EDS, XRD, and NH 3 -TPD methods, and direct coal liquefaction performance of the catalysts was performed, and TG-DTG characterization was used to evaluate the pyrolysis behavior of the liquefaction residue. Results showed that activity of the four supported solid super-acid catalysts was followed by TFMSA/ZrO 2 , TFMSA/ZSM-5, TFMSA/Al 2 O 3 , and TFMSA/SiO 2 , with coal conversions of 84.20 %, 78.40 %, 76.67 % and 73.23 %, and oil yields of 67.16 %, 62.53 %, 61.15 %, and 58.41 %, respectively. The Coast-Redfern method was used to analyze the pyrolysis kinetics of the four coal liquefaction residues (R-ZrO 2 , R-ZSM-5, R-Al 2 O 3 , and R-SiO 2). Results presented that, in low temperature range (200−530 ℃), except R-SiO 2 , the pyrolysis process of residues conforms to the third-order reaction. And in high temperature range (530−850 ℃), the four-order reaction is more suitable for the four residues. The pyrolysis activation energy of R-ZrO 2 is lower at low temperature region (16.822 kJ/mol), while R-Al 2 O 3 presents lower activation energy at high temperature range (45.494 kJ/ mol). [ABSTRACT FROM AUTHOR]