Fuel Processing Technology (v.136, #C)

Sequential extraction and characterization of liquefaction residue from Shenmu–Fugu subbituminous coal by Peng Li; Zhi-Min Zong; Fang-Jing Liu; Yu-Gao Wang; Xian-Yong Wei; Xing Fan; Yun-Peng Zhao; Wei Zhao (1-7).
Liquefaction residue from Shenmu–Fugu subbituminous coal (LRSFSBC) was fractionated into extracts 1–6 (E1–E6) and inextractable portion (IEP) by sequential extraction with petroleum ether, cyclohexane, methanol, acetone, carbon disulfide (CDS), and isometric CDS and acetone mixture (ICDSAM) followed by analyses with Fourier transform infrared (FTIR) spectrometer, gas chromatography/mass spectrometer (GC/MS) and atmospheric solid analysis probe/time of flight mass spectrometer (ASAP/TOF-MS). In total, 69.06% of LRSFSBC were extracted by the sequential extraction. Large amounts of multi-substituted alkylarenes and hydroarenes were identified in LRSFSBC according to GC/MS and FTIR analyses. A series of nitrogen heterocyclic aromatics and arylamines in LRSFSBC were enriched in E3. In total 61 compounds were detected with GC/MS, including 48 arenes with a total relative content of 98.72%, while 478 organooxygens, organonitrogens, organosulfurs, and organochlorines were detected with ASAP/TOF-MS. The double bond equivalent, carbon number, and molecular mass distribution of the compounds range from 0 to 13, 6 to 23, and 230 to 511 Da, respectively, by ASAP/TOF-MS analysis. E1 with the yield of 33.47% could be converted to light oil by catalytic hydroconversion due to its high H/C ratio and low sulfur content, while E5 could be a promising precursor for preparing carbon materials because of its high carbon content and C/H ratio.
Keywords: Coal liquefaction residue; Sequential extraction; Composition; ASAP/TOF-MS analysis;

Methanolysis of extraction residue from Xianfeng lignite with NaOH and product characterizations with different spectrometries by Fang-Jing Liu; Xian-Yong Wei; Wei-Tu Li; Juan Gui; Peng Li; Yu-Gao Wang; Rui-Lun Xie; Zhi-Min Zong (8-16).
Extraction residue (ER) from Xianfeng lignite via ultrasonic extraction was subjected to methanolysis in the presence of NaOH at 300 °C for 2 h, and extracts 1–4 (E’1-E’4) from ER methanolysis were acquired by subsequent separation of the resulting soluble portion (SP). NaOH could promote ER methanolysis and hence increased the SP yield. Detailed molecular compositions (MCs) of E’1-E’4 were characterized with Fourier transform infrared spectrometer, gas chromatograph/mass spectrometer (GC/MS), direct analysis in real time ionization source coupled to ion-trap mass spectrometer (DARTIS/ITMS), and atmospheric solid analysis probe/time of flight-mass spectrometer (ASAP/TOF-MS). The results show that the SP is rich in aliphatic moieties, carbonyl and hydroxy groups, and has molecular mass distribution ranging from m/z 100 to 600. According to GC/MS analysis, phenols, especially polymethylphenols, were enriched in E’1 and E’2, whereas almost all the alkanoic acids, alkanedioic acids, benzoic acids, and phenyl-substituted alkanoic acids only appeared in E’4. A series of polar and/or involatile organic species, which are difficult to be detected with GC/MS, were detected with DARTIS/ITMS and ASAP/ TOF-MS. NaOH could play an important role in cleaving ether bonds in ER during methanolysis and thereby enhanced the formation of oxygen-containing organic species. The use of multiple spectrometries provides a promising approach for understanding MC of the SP from coals.
Keywords: Methanolysis; Molecular composition; GC/MS; DARTIS/ITMS; ASAP/TOF-MS;

Preparation of nickel-loaded on lignite char for catalytic gasification of biomass by Ben-Shui Wang; Jing-Pei Cao; Xiao-Yan Zhao; Yue Bian; Chong Song; Yun-Peng Zhao; Xing Fan; Xian-Yong Wei; Takayuki Takarada (17-24).
A novel catalyst was prepared by loading nickel on Shenli lignite char via ion-exchange. The results show that the nickel crystallite size (NCS) and specific surface area (SSA) of the catalyst significantly depended on solution pH and carbonization temperature. The catalyst prepared in pH 11 at 650 °C reached the maximum SSA of 236.3 m2/g and the nickel particles dispersed quite well in the catalyst with a NCS of 5.6 nm. The catalyst was used for corncob volatiles reforming in a two-stage fixed-bed reactor to study the effects of temperature, steam, and space velocity on gas yields and carbon distributions. It effectively improved tar decomposition at 650 °C under inert atmosphere and produced a tar-free syngas in a yield of 43.9 mmol/g, which is higher than that over a commercial Ni/Al2O3. The increase of the NCS during catalytic reforming above 650 °C leads to the catalyst deactivation for tar decomposition. The study revealed the possibility of using Ni/char as a potential catalyst for low-temperature gasification of biomass.
Keywords: Corncob; Catalytic reforming; Nickel loaded on lignite char; Tar decomposition; Nickel crystallite size;

Viscosity of coal ash slag containing vanadium and nickel by Zhigang Wang; Jin Bai; Lingxue Kong; Xiaodong Wen; Xiaoming Li; Zongqing Bai; Wen Li; Yue Shi (25-33).
The viscosity–temperature behaviors of ashes with different ratios of V2O5 and NiO were studied. XRD, FTIR, XPS, Raman and SEM-EDX were applied for investigating the mechanism of influences on viscosity by V and Ni based on the formation of crystalline phase and the change of molecule network structure of liquid phase. Under reducing atmosphere, V2O5 was reduced to V2O3 which forms V―O―Al bond with Al2O3. The penetration of Al3 + into the original tetrahedral [SiO4]4 − skeleton was blocked and the framework size of aluminosilicate reduces, so the viscosity of liquid slag decreased significantly. However, the formation of vanadium-rich spinel increased the viscosity of slag and type of slag transformed into crystalline type for spinel precipitating at high temperature. When the temperature was below the melting temperature of Ni, the existence of metal Ni changed slag into crystal type, and viscosity increased sharply. During coexistence of V and Ni, Ni particles were covered by vanadium-rich spinel, which caused Tcv (temperature of critical viscosity) of slag containing VNiO to be lower than that of slag containing V or Ni.
Keywords: Viscosity–temperature curve; Vanadium; Nickel; Gasification slag; Petroleum coke; Crystalline;

The purpose of this study is to prepare novel carbon-supported Ni (Ni/C/Al2O3) catalysts by the sol–gel method and to perform the hydrothermal gasification of phenol water as a model of wastewater. Catalysts were prepared by the combination of aluminum tri-sec-butoxide (ASB) and tartaric acid as an organic template and the addition of active metal, nickel nitrate hexahydrate at the preparation of catalysts. After calcination under the nitrogen atmosphere, the larger amounts of active metal species were built at the carbon skeletal in the catalysts. Introduction of tartaric acid dispersed metal Ni with high loading on carbon derived from ammonium tartrate. Hydrothermal gasification was performed under the following conditions: 350 °C, pressure of 20 MPa, phenol water of 2–20 g/L, and LHSV of 48 h−1. 16N63C21A catalyst, which represents 16 wt.% Ni, 63% carbon in tartalic acid, and 21% Al2O3 at the preparation of the catalyst, showed the highest activity and the highest carbon balance between feed and products within 8 h among all the Ni catalysts. The activity of each catalyst increased with the elapse of time and the phenol conversion reached 100 % under the condition and phenol concentration of 2 g/L. No deactivtion was observed.Display Omitted
Keywords: Hydrothermal gasification; Phenol water; Carbon-supported Ni catalysts; Tartaric acid; Alminum tri-sec-butoxide;

Controlled separation of low temperature coal tar based on solvent extraction–column chromatography by Ming Sun; Jing Chen; Xiao-min Dai; Xiang-long Zhao; Ke Liu; Xiao-xun Ma (41-49).
The heavy tar (H-tar) of low temperature coal tar was collected from a low temperature carbonization plant in Shanbei. H-tar was separated into eight fractions by silica-gel column chromatography (SGCC) with a binary eluent of n-hexane and ethyl acetate (EA). A series of alkanes (C14–C28), phenolic compounds and aromatic nitrogen species were fractionated from H-tar by SGCC and analyzed by gas chromatography–mass spectrometry (GC–MS). Most of the GC–MS detectable phenolic compounds are phenol, cresol, xylenol, C3–C4 alkyl phenols, indanols, naphthalenols, methyl naphthalenols, benzenediols, fluorenols, phenanthrols and pyrenol, among which cresol is the most abundant one and pyrenol is the largest molecular weight one. According to the change rule of phenolic compounds with the polarity of eluting solvents, the solvent extraction–column chromatography (SECC) device and crude phenol recovery processing have been designed and developed, which could realize the separation of neutral oil, pitch and crude phenol from low temperature coal tar.
Keywords: Low temperature coal tar; Column chromatography; Extraction; Crude phenol; GC–MS;

Liquefied petroleum gas (LPG) synthesis from CO2 hydrogenation was carried out in a new technical route consisting of two packed tubular reactors in series with an inter-stage water removal. In this way, CO2 was transformed to DME-rich products in the first stage over the Cu–Zn–Zr–Al/Pd-β catalyst and then to hydrocarbons in the second stage over the Pd-β catalyst. CO2 conversion and LPG selectivity were mainly dominated by the first and second stages, respectively. The obtained results disclosed that the reaction performance of the two-stage process with intercooler was significantly superior to the single-stage process and its analog without intercooler for either yield or selectivity of the target product. The tests were conducted at 260–300 °C, 2.0–3.3 MPa, with a H2/CO2 mole ratio of 3–5. It is noted that the hybrid catalyst gave conversion as high as 85% with high hydrocarbon selectivity by using the designed reaction system.Display Omitted
Keywords: LPG synthesis; Two-stage process; CO2;

Oxidation of Shenmu char powder with aqueous hydrogen peroxide–acetic anhydride by Yu-Gao Wang; Xian-Yong Wei; Jing Liu; Hong-Lei Yan; Zhe-Hao Wei; Yan Li; Peng Li; Fang-Jing Liu; Zhi-Min Zong (56-63).
The mild oxidation of Shenmu char powder (SCP) with aqueous hydrogen peroxide (AHPO)–acetic anhydride (AAH) was carried out under different conditions, including volume-to-mass ratio of AAH to SCP (AAH/SCP), temperature, volume ratio of AHPO to AAH (AHPO/AAH), and time. Each reaction mixture was filtrated and then extracted with methanol to afford residue and extract. The optimal conditions were determined to be 60/1 of AAH/SCP, 50 °C, 2 of AHPO/AAH and 60 h based on the extract yield. The extracts from SCP oxidation after different periods of time ranging from 12 to 72 h were analyzed with a gas chromatograph/mass spectrometer (GC/MS) and atmospheric pressure solid analysis probe/time-of-flight mass spectrometer (ASAP/TOF-MS). In total, 46 compounds were identified in the extracts by GC/MS analysis and carboxylic acids are predominant. Malonic acid and succinic acid were detected in the extracts and their total mass content in the extracts is up to 56.5%. A series of long-chain alkenedioic acids or long-chain cycloalkanedioic acids with molecular formulae C29H56(CH2)n(COOH)2 (n = 0–6) were detected in the extracts with ASAP/ TOF-MS.
Keywords: Char powder; Hydrogen peroxide–acetic anhydride; Mild oxidation; Mass spectral analyses;

Cu recovery from industrial wastewater using brown coal by Atsushi Yoshino; Ryosuke Yamato; Kazuyoshi Sato; Takayuki Takarada (64-67).
The etching process by copper chloride is widely used in printed wiring board manufacturing. Brown coal has an ion exchange ability because it has carboxy groups and hydroxyl groups in it. Using this ability of brown coal, the copper recovery from the waste etching solution by low energy consumption method is studied. Copper ion in the waste solution can be loaded on Loy Yang brown coal around 8.5 wt.% by adding ammonium hydroxide, adjusting pH to 9–11.5 and stirring the solution at room temperature. Cu-loaded brown coal can be burnt at extremely low temperature; 160–180 °C, and 0.5–1.0 μm copper oxide particles are formed as the residue. In order to commercialize the copper recovery system, since Cu-loading amount and low temperature combustion of Cu-loaded brown coal are key factors of this process cost, Cu-loading conditions and the reaction kinetics of low temperature combustion of Cu-loaded brown coal by TG analysis are studied. By the kinetic analysis using TG data, activation energy of initial combustion is affected by Cu-loading amount. When Cu-loading is 8.6 wt.%, it is estimated that the activation energy is reduced to 56% of that of the raw coal.
Keywords: Copper recovery; Brown coal; Wastewater; Low temperature combustion; Catalyst;

Tunable isoparaffin and olefin synthesis in Fischer–Tropsch synthesis achieved by composite catalyst by Chuang Xing; Jian Sun; Guohui Yang; Wenzhong Shen; Li Tan; Pengfei Zhu; Qinhong Wei; Jie Li; Masahiro Kyodo; Ruiqin Yang; Yoshiharu Yoneyama; Noritatsu Tsubaki (68-72).
Hierarchical HZSM-5 zeolite with combined micropores and mesopores was synthesized by one-step approach with TPAOH and F127 as dual templates. The physical and acidic properties of the hierarchical HZSM-5 zeolite were characterized by XRD, N2 adsorption–desorption isotherm, SEM, TEM, and NH3-TPD techniques. The hierarchical HZSM-5 zeolite exhibited a significantly higher mesopore surface area and larger mesopore volume than that of the conventional HZSM-5. The prepared hierarchical HZSM-5 and conventional HZSM-5 zeolite supported cobalt catalysts were evaluated via Fischer–Tropsch synthesis (FTS) reaction to tune product selectivity. Compared with the conventional catalyst, the CO conversion of FTS reaction on the present catalyst increased significantly. Meanwhile, the C5 + selectivity and isoparaffin selectivity also increased. The C5–11 hydrocarbons with a lot of isoparaffin and olefin had become the main FTS products due to the optimized hydrocracking and isomerization afforded by the hierarchical pore structure, different from the conventional FTS hydrocarbons which were mainly composed of normal paraffin.Display Omitted
Keywords: Hierarchical; HZSM-5; Mesopore; Fischer–Tropsch synthesis; Isoparaffin;

In-situ reforming of the volatiles from fast pyrolysis of ligno-cellulosic biomass over zeolite catalysts for aromatic compound production by Kazuhiro Uemura; Srinivas Appari; Shinji Kudo; Jun-ichiro Hayashi; Hisahiro Einaga; Koyo Norinaga (73-78).
Characteristics of in-situ catalytic reforming of the products derived from fast pyrolysis of biomass were studied with an originally designed analytical pyrolysis technique. The volatile products derived from ligno-cellulosic biomass as well as cellulose, xylan, and lignin were converted using a two-stage tubular reactor at 550 °C over various zeolite catalysts with different acidities and pore structures. HZSM-5 exhibited the best performance for converting the cedar derived volatiles to arenes, which mainly composed of benzene, toluene, and naphthalene with a selectivity of 26% on carbon basis. The HZSM-5 had a little effect in increasing the yields of the arenes for xylan and lignin, while it had a significant effect for cellulose, showing that more than 30% of carbon in cellulose was converted into arenes. A reaction pathway analysis for reforming of volatiles suggested that alkyne and diene such as acetylene, propyne, and cyclopentadiene are the important precursors of the major aromatic hydrocarbon products such as benzene, toluene, and naphthalene. The formations of those intermediates were also confirmed experimentally in an early stage of the in-situ reforming.
Keywords: Catalytic reforming; Reaction mechanism; Nascent volatiles from ligno-cellulosic biomass; Arenes; Zeolite catalysts;

An exergy recuperative module was developed and applied to biomass drying. The proposed drying process has an energy consumption 1/20 that of a conventional heat recovery drying system. Experimental work was conducted to confirm the details of the self-heat recuperation technology concept. A high drying rate and a stable heat exchange were found through the experimental drying results. Furthermore, the heat pairing was confirmed in the drying system for the first time.
Keywords: Drying; Self-heat recuperation technology; Steam; Heat pairing;

Effective activation of montmorillonite and its application for Fischer-Tropsch synthesis over ruthenium promoted cobalt by Yong-Hua Zhao; Yan-Jiao Wang; Qing-Qing Hao; Zhao-Tie Liu; Zhong-Wen Liu (87-95).
The natural Na-type montmorillonite (Na-MMT) suspended in the 20 wt.% HNO3 aqueous solution at concentrations between 2-20 wt.% was activated at 70–104 °C for a period, respectively. The thus obtained materials were abbreviated as acid-MMT-m-t/T, where m, t and T are the concentration of Na-MMT suspension (wt.%), time (h), and temperature (°C) during the acid activation, respectively. The Co-Ru/acid-MMT (20 wt.% Co and 0.1 wt.% Ru) was prepared by the incipient impregnation method. The materials were characterized by XRD, FT-IR, XRF, N2 adsorption-desorption at low temperature, H2-TPR, H2-TPD, oxygen titration, and NH3-TPD techniques. In comparison to the results of the Na-MMT, the structural, textural, and acidic properties of the acid-MMTs were clearly changed, the extent of which is strongly dependent on the acid activation conditions. For the first time, the acid-MMT with desired properties were obtained using a high ratio of Na-MMT suspension, such as 10 wt.%, leading to a significantly improved process efficiency of the acid activation. The structural and compositional changes of acid-MMTs gave significant impacts on the reduction behavior of Co-Ru/acid-MMT catalysts. Moreover, the addition of Ru to Co/acid-MMTs decreased the peak temperatures of the two-step reduction of Co3O4 to Co via the CoO intermediate, leading to an increased extent of reduction of cobalt. The catalysts were comparatively investigated for Fischer-Tropsch (FT) synthesis in a fixed-bed reactor under the conditions of H2/CO = 2, W/F = 5.0 g · h · mol− 1, 235 °C, and 1.0 MPa. Results showed that the CO conversion was decreased in the order of Co-Ru/acid-MMT-2-12/104 > Co-Ru/acid-MMT-10-12/104 > Co-Ru/acid-MMT-20-12/104 ≫ Co-Ru/acid-MMT-2-12/70 > Co-Ru/acid-MMT-2-4/70 > Co/acid-MMT-2-4/70. Moreover, all of the Co-Ru/acid-MMT catalysts showed clearly higher selectivity of C5-C12 hydrocarbons and lower selectivity of C21 + hydrocarbons compared with Co/SiO2 catalyst. The Co-Ru/acid-MMT-2-12/70 showed about 46% C5-C12 selectivity at a reasonable CO conversion level.Display Omitted
Keywords: Fischer-Tropsch synthesis; montmorillonite; acid activation; cobalt; ruthenium;

Supercritical hydrothermal synthesis of zeolites from coal fly ash for mercury removal from coal derived gas by Jiancheng Wang; Dekui Li; Fenglong Ju; Lina Han; Liping Chang; Weiren Bao (96-105).
The supercritical hydrothermal method was proposed as a new approach to synthesize zeolite from Coal fly ashes (CFAs). Eight kinds of CFAs from different power plants were used as raw material. The effects of the types of CFAs, the concentration of NaOH, liquid-solid volume ratio, reaction time and SCW temperature on the formation of zeolites and their properties were investigated. All the CFAs can form zeolite in supercritical conditions in 5 min at 400 °C, especially for the coal fly ash with medium mass ratio of SiO2/Al2O3 and low content of Fe2O3 and CaO. The different type of zeolites (cancrinite and sodalite) could be formed by changing the solution concentration of NaOH. The best crystallinity can be obtained under the conditions of the SCW temperature of 400 °C, liquid-solid volume ratio of 15:1 and NaOH concentration of 1 mol/L. The potential application of the products synthesized from CFAs was studied and the results suggested that CFA zeolites had a good activity for Hg removal from the simulation coal gas.
Keywords: Coal fly ash; Supercritical hydrothermal synthesis; Zeolite; Hg removal;

Effects of flue gas re-circulation and nitrogen contents in coal on NOX emissions under oxy-fuel coal combustion by Ryo Yoshiie; Naoki Hikosaka; Yoko Nunome; Yasuaki Ueki; Ichiro Naruse (106-111).
Oxy-fuel coal combustion has drawn attention as a useful technique to achieve carbon dioxide capture and storage (CCS). It is the technique that enriches CO2 in exhaust gas by flue gas recirculation with additional pure O2, which makes it easy to capture and liquidize CO2 downstream. However, in the oxy-fuel combustion system, various impurities in the flue gas are brought back to the combustion zone with recirculated flue gas, and more have accumulated in a boiler compared with the air combustion system. NOX formations, in particular, can be affected by nitrogen contents in the raw coal and recirculated multiple NOX compounds, such as NO and N2O. Then, in this study, we experimentally estimated the effects of NO and N2O recirculation by a drop tube furnace equipment simulating oxy-fuel atmosphere for three coal samples with different nitrogen contents. As a result, contributions of recirculated NOX to NOX emissions were found to be very small in oxy-fuel coal combustion. Instead, nitrogen conversion ratios to NO and N2O were governed by the ratio of char-N to fuel-N.
Keywords: Oxy-fuel coal combustion; Flue gas recirculation; NO and N2O; Nitrogen content in coal;

Xilinguole lignite pyrolysis under methane with or without Ni/Al2O3 as catalyst by Chan Dong; Lijun Jin; Shuaijiang Tao; Yang Li; Haoquan Hu (112-117).
The effect of methane on Xilinguole lignite (XL) pyrolysis with or without Ni/Al2O3 as catalyst was investigated with thermogravimetry coupled with mass spectrometer and in a fixed-bed reactor. The results show that methane activated by catalyst can promote XL pyrolysis, increasing tar yield and gas releasing. Methane without catalyst can also enhance gas evolution of XL pyrolysis, but has little effect on tar yield. The increase of char yield in XL pyrolysis under methane is attributed to carbon deposited from methane decomposition. There exists induce effect between coal radicals and methane which facilitates methane activation at low temperature and increases gas evolution during XL pyrolysis even without catalyst.
Keywords: Coal pyrolysis; Methane; Ni/Al2O3; Gas evolution; TG-MS;