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To achieve energy security in an environmentally benign way, China has to convert a significant fraction of its abundant coal resource to clean fuels (liquid fuels or synthetic natural gas, SNG) to meet the fast increasing demand on transportation fuel and municipal gas. Following the successful operation of the 4000 bbl/d Yitai and Luan coal-to-liquids plants using the medium temperature Fischer Tropsch synthesis (MTFT) process technology from Synfuels China, tremendous progresses have been made in upscaling the Fischer–Tropsch synthesis (FTS) process in China. Past experiences gained from the efforts in this field have shown that further exploration in the coal conversion field requires significant technological improvement on gasification, synthesis, and utilities related to integrating more efficient and environmentally friendly processes on the basis of current status of applications. [ABSTRACT FROM AUTHOR]

An industrial manganese-promoted ultrafine particle (UFP) iron catalyst for slurry phase Fischer–Tropsch synthesis was examined in a 1 dm3 stirred tank slurry reactor under various reaction conditions as a representative of industrial practice (533–573 K, 1.5–2.5 MPa, 1.0–2.5 l (STP)/g-cat h, H2/CO=0.65–2.0). The Fe–Mn UFP catalyst showed high CO conversion and gave high yields of C2–C4 alkenes, partially attributed to less secondary hydrogenation of alkenes during the slurry reaction. The catalyst displayed a slow deactivation rate with time on stream. The effects of reaction conditions on the catalytic activity, hydrocarbon product distribution and the ratio of alkene/alkane were discussed. [Copyright &y& Elsevier]

Fatty acid methyl esters (FAMEs) were produced from housefly ( Musca domestica L.) larvae fed by poultry manure. The larval lipid output was 23.6 g from 1 kg poultry (107.3 g fresh larva), under conditions: inoculum density of 8000 larvae/kg, 28 °C, and 4 days. A practical method involving physical refining were developed specifically for housefly larval lipid (acid value = 15.1 mg KOH/g). With evaporator temperature of 155 °C, fatty acids distilled from molecular distillation were esterified with methanol catalyzed by benzenesulfonic acid (BSA) and residue, acylglycerols (fatty acids removal rate: 96.96%wt.), were transesterified with methanol using NaOH catalyst to produce fatty acid methyl ester biodiesel. Residual alkali catalyst in glycerol after transesterification was used to neutralize the acid catalyst and FFA from esterification. Acid value (AV) of esterification product (2.72 mg KOH/g) were lowered to 0.34 mg KOH/g. Biodiesel produced from housefly larval oil (HLO) satisfies the ASTM D6751-10 standard. [ABSTRACT FROM AUTHOR]

Sn-containing Fe 5 C 2 interface not only can boost the rates of oxygen removal but also restrain the coke deposition by elevating the barrier of nucleation, which stabilizes the active iron carbide structure and enhanced the stability remarkablely. [Display omitted] • Oxygen removal by carbon oxide is facilitated for Fe-Sn interface； • Coking deposition was inhibited remarkably for Fe-Sn bimetallic catalysts; • Catalytic stability was significantly enhanced for Sn0.25 and Sn0.50 catalysts; • Provided a strategy to construct durable catalysts under the perspective of oxygen removal and coking resistance. Comprehending deactivation mechanisms and constructing durable Fe-based catalysts remain a substantial challenge for Fischer-Tropsch synthesis. In this contribution, the effects of Sn promoter on the structure and catalytic performance of Fe-based catalysts were investigated systematically. The catalytic stability was enhanced significantly for 100Fe/0.25Sn and 100Fe/0.50Sn catalysts, reducing the deactivation rate almost four-fold and seven-fold respectively. Combined with several characterizations and DFT calculation, it has been confirmed that Sn-containing Fe 5 C 2 interface not only can boost the rates of oxygen removal but also restrain the coke deposition by elevating the barrier of nucleation, which stabilizes the active iron carbide structure and inhibits the deactivation efficiently. This study may broaden the understanding of enhanced stability during Fe-based FTS under the perspective of oxygen removal and coking resistance and provide a strategy to construct durable catalysts. [ABSTRACT FROM AUTHOR]

Abstract: This paper designs four cases to investigate the performances of the polygeneration processes, which depend on the commercially ready technology to convert coal to liquid fuels (CTL) and electricity with CO2 sequestration. With Excel-Aspen Plus based models, mass and energy conversion are calculated in detail. The simulation shows that the thermal efficiency is down with the synfuels yield decrease though the electricity generation is increased. It also suggests that the largest low heat value (LHV) loss of coal occurs in the gasification unit. From the comparison of the four cases, prominent differences of coal energy transition appear in water–gas shift (WGS) units, Fischer–Tropsch (FT) synthesis and combined cycle processes. CO2 capture and vent are discussed and the results show that the vent amount of CO2 increases with the increase of percentage of the syngas going to produce electricity. The results also show that the ratio of carbon captured to total carbon increases from 58% to 93% which is an important contribution to cutting down the greenhouse gas vent. [Copyright &y& Elsevier]

Abstract: A systematic study was undertaken to investigate the effects of Al2O3/SiO2 ratio on reduction, carburization and catalytic behavior of iron-based Fischer–Tropsch synthesis (FTS) catalysts promoted with potassium and copper. The catalysts were characterized by N2 physical adsorption, CO2 temperature-programmed desorption (TPD), H2 temperature-programmed reduction (TPR) and Mössbauer effect spectroscopy (MES). CO2-TPD indicated that Al2O3 binder has stronger acidity than SiO2 binder and weakens the surface basicity of the catalysts. H2-TPR profiles suggested that the lower Al2O3/SiO2 ratio promotes the reduction of Fe2O3→Fe3O4. With further increasing Al2O3/SiO2 ratio, the transformation of Fe2O3→Fe3O4 shifts to higher temperatures. The MES results showed that the increase of Al2O3/SiO2 ratio leads to the relatively large crystallite size of α-Fe2O3 and inhibits carburization of the catalyst. During reaction tests in a fixed bed reactor it was found that a maximum in catalyst activity is noted at the Al2O3/SiO2 ratio of 5/20 (weight basis). The selectivity to olefins shows a rapid decrease and the formations of methane and light hydrocarbons are promoted with increasing Al2O3/SiO2 ratio. The oxygenate selectivity in total products increases with increasing Al2O3/SiO2 ratio. [Copyright &y& Elsevier]

Abstract: The kinetics of water gas shift (WGS) reaction over an Fe–Mn catalyst under Fischer–Tropsch synthesis (FTS) reaction conditions is studied in a spinning basket reactor. Experimental conditions are varied as follows: temperature of 533–573K, reactor pressure of 10.0–26.5bar, H2/CO feed ratio of 0.66–2.0 and space velocity of 0.66–2.65×10−3 Nm3 kgcat −1 s−1. By separately fitting WGS kinetics parameters with experimental data, which is possible in the spinning basket reactor with neglecting concentration and temperature gradients, different kinetics models of WGS are derived and discriminated on the basis of four sets of WGS elementary reactions. Kinetics experimental results show that the WGS reaction under FTS reaction conditions is far from equilibrium. Two types of WGS mechanisms are investigated. One is the formate mechanism, and the other is the direct oxidation mechanism. It is found that the formate mechanism is better in fitting experimental data than the direct oxidation mechanism over the Fe–Mn catalyst under the FTS reaction conditions. The optimized kinetics model with formate intermediate dissociation as the rate-determining step (RDS) can fit the WGS experimental results well. The simplified WGS kinetics model can easily be used for industrial modeling applications. [Copyright &y& Elsevier]

Abstract: The kinetics models of oxygenate formation in Fischer–Tropsch synthesis (FTS) over an industrial Fe–Mn catalyst are studied in a continuous spinning basket reactor. Detailed kinetics models on the basis of possible oxygenate formation mechanisms, namely adsorbed CO or CH2 insertion mechanisms, are derived. The calculated alcohol and acid distributions in FTS reaction fit the experimental data well with considering the esterification reactions between alcohols and acids. The alcohol formation via successive hydrogenation of intermediate [RCO-s] is more energetically favorable than the acid formation via the reaction between the [RCO-s] and [OH-s]. The alcohol formation is not via the successive hydrogenation of acid intermediates over the Fe–Mn catalyst under FTS reaction conditions. [Copyright &y& Elsevier]

A precipitated iron catalyst containing sulfur for Fischer–Tropsch (F–T) synthesis was prepared by means of a novel method using a ferrous sulfate as precursor. Both fixed bed reactor (FBR) and continues stirred tank slurry reactor (STSR) were used to test long-term F–T reaction behaviors over the catalyst. A stability test (1600 h) in FBR showed that the catalyst was active even after 1500 h of time-on-stream with CO conversion of 78% and with C5+ hydrocarbon selectivity of 72 wt% at 250 °C, 2.0 MPa, 2.0 NL/g-cat/h, and H2/CO=2.0. The test (550 h) in STSR indicated that the catalyst exhibited relatively high activity with CO conversion of 70–76% and C5+ selectivity of 83–86 wt% in hydrocarbon products under the conditions of 260 °C, 2.0 MPa, 2.0 NL/g-cat/h, and H2/CO=0.67. The deactivation rate of the catalyst was low, accompanied by surprisingly low methane selectivity of 2.0–2.9 wt%. It is shown that a small amount of sulfur (existing as SO42−) may promote the catalyst by increasing activity and improving the heavier hydrocarbon selectivity. It is also comparable with other typical iron catalysts for F–T synthesis. [Copyright &y& Elsevier]

The kinetic experiments of Fischer–Tropsch synthesis (FTS) over an industrial Fe–Cu–K catalyst are carried out in a micro-fixed-bed reactor under the conditions as follows: temperature of 493–542 K, pressure of 10.9–30.9 bar, H2/CO feed ratio of 0.98–2.99, and space velocity of 4000–10 000 h−1. The effects of secondary reactions of olefins are investigated by co-feeding C2H4 and C3H6. A detailed kinetics model taking into account the increasingly proven evidence of the olefin re-adsorption mechanism is then proposed. In this model, different sites are assumed for FTS reactions and water gas shift (WGS) reaction, respectively. Rate expressions for FTS reactions are based on the carbide polymerisation mechanism, in which olefin re-adsorption is considered to be a reverse step of olefin desorption reaction. Rate expression for WGS reaction is based on the formate mechanism. An integral reactor model considering both FTS and WGS kinetics is used to describe the reaction system, and the simultaneous estimation of kinetic parameters is conducted with non-linear regression procedure. The optimal model shows that the rate determining steps in FTS reactions proceed via the desorption of hydrocarbon products and the adsorption of CO and the slowest step in WGS reaction is the desorption of gaseous carbon dioxide via formate intermediate species. The activation energies of FTS reactions and WGS reaction are in good agreement with literature values. [Copyright &y& Elsevier]

• The dispersion of iron species is greatly enhanced by B 2 O 3. • The interaction between iron and boron render the electron deficiency of iron species. • The promotion of B 2 O 3 result in higher tendency to H 2 rather than CO for doped catalysts. • B 2 O 3 greatly inhibit the coke deposition of catalysts and promotes the hydrogenation activity of catalyst. Experimental improvement on the suppression of coke deposition remains a substantial challenge in iron-catalyzed Fischer-Tropsch Synthesis. Here, we performed a thorough study to provide in-depth understanding of the coking resistant as well as intrinsic promotive effect of boron oxide on the iron-based catalysts, by excluding the possible interference from another components. It turns out that the dispersion of catalysts is improved by boron oxide doping, which simultaneously inhibit the reduction of iron species in the catalysts. Strikingly, both the coking resistant behavior and hydrogenation activity of single active site of catalysts is greatly enhanced with addition of boron oxide. Such dual pronounced influence has been tentatively reasoned as the electronic interaction between Fe and B that render the electron deficiency of iron species, which thereby result in weaker adsorption capability of CO while inversely promote the chemisorption of H 2 for B 2 O 3 -doped catalysts. As a consequence, the ratio of H/C on the surface of B 2 O 3 -doped catalysts is greatly enhanced with respect to undoped one, thus facilitate the formation of hydrocarbons via hydrogenation of surface carbon species rather than the competitive coke deposition. [ABSTRACT FROM AUTHOR]

• Pd@Beta and Pd@MOR with encapsulation structure can be prepared by seeding method. • Pd@Beta and Pd@MOR can obtain higher Pd dispersion and aggregation resistance. • The encapsulated bifunctional catalysts exhibit higher isomerization selectivity. • Zeolite topology and size may affect the intimacy of the encapsulated catalysts. The bifunctional catalysts capable of regulating the metal dispersion and location through encapsulating palladium (Pd) nanoparticles inside Beta and mordenite (MOR) zeolites were used for n-heptane hydroisomerization. Several characterizations such as X-ray powder diffraction (XRD), scanning electron microscope (SEM), N 2 -adsorption and so on suggested that the difference in the phase, textural property, morphology, and acidity of zeolites between the catalysts with encapsulation structure and prepared by impregnation method was negligible whether Beta- or MOR-series catalysts. Nevertheless, the higher Pd dispersion, smaller Pd particle size, and higher aggregation resistance can be achieved on the encapsulation catalysts as determined by H 2 -pulse and transmission electron microscopy (TEM). Compared to the palladium-loading catalyst prepared by conventional impregnation method, the encapsulation structure guaranteed the higher selectivity and yield in n-heptane isomerization due to the significantly improved balance and intimacy. Furthermore, the catalyst with the complete encapsulation structure for the Beta-series catalysts and the catalyst with partial encapsulation structure for the MOR-series catalysts respectively exhibited the highest isomer selectivity and yield. All results may be resulted from that the zeolite topology and crystal size acted a significant role in determining the intimacy of the bifunctional catalysts with encapsulation structure, due to the different diffusion hurdles of the channels structure. [ABSTRACT FROM AUTHOR]