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Abstract: CH4 pyrolysis and CH4-CO2 reforming to produce syngas was carried out in a quartz tubular reactor over blank and carbonaceous catalyst. Material balance analysis of C atom was conducted according to the calculatedH. The gas composition was detected by an on line gas chromatograph with FPD and PID detector. It was found that CH4 pyrolysis decomposed into carbon and H2. For CH4-CO2 reforming, firstly CH4 decomposed into carbon and H2, the carbon then reacts with carbon monoxide to form carbon dioxide. As a comparison, blank tests were also performed. The results showed that the carbonaceous catalyst greatly decreased the initial reaction temperature (about decreased 50°C), and promoted CH4 conversion. From the material balance analysis of C atom, it can be found that the mass of carbonaceous catalyst reduce during the carbon dioxide reforming reaction of methane. It indicated that the gasification of carbonaceous materials by CO2 takes place during the synthesis process. The consumption kinetics parameters of carbonaceous materials were determined by an overall unreacted shrinking core model. The apparent activation energy of consumption carbonaceous materials was more than 230kJ/mol during CH4-CO2 reforming. [Copyright &y& Elsevier]

Reports research on uniform shape platinum nanocrystals with narrow size distribution and controlled average dimension, which are embedded in a polymeric matrix and supported on zeolite Β. Investigation into the surface structure and reactivity of nanometalclusters; Use of TEM, EXAFS, CO adsorption and methane activation; Finding that the surface activity and reactivity of nanometalparticles in PVP-Pt/Β materials is high enough to activate methane even at a temperature of 373K.

The Chinese government is going to "push ahead the revolution of energy production and consumption, and establish a clean, low-carbon, secure, and efficient energy system", which points out a direction for the energy industry in the new era. Using the analytic hierarchy process of the system analysis method, we constructed an indicator system of the modern Chinese energy system, and by determining the weighting of each indicator, we obtained the composite index of the modern Chinese energy system, as well as four sub-indexes of clean, low-carbon, secure, and efficient. Then, we investigated policy changes and energy development characteristics of important periods, and performed historical trend analysis. Finally, we forecasted the composite index and four sub-indexes by 2050, and proposed an energy development path and policy suggestions to achieve a modern Chinese energy system as soon as possible. [ABSTRACT FROM AUTHOR]

[Display omitted] • SO 2 possessed both a facilitating and inhibiting effect on the oxidation of Hg0. • The bidirectional effect of SO 2 was equilibrated when sulfate deposited to 3.88%. • The coexistence of SO 2 and SCR atmosphere aggravated the induced reduction of HgO. • SCR atmosphere enhanced the inhibition of SO 2 by upsetting reaction equilibrium. Collaborative control of Hg0 in selective catalytic reduction (SCR) device is considered to be feasible and cost-effective, whereas the negative impact of SO 2 remains a thorny issue for industrial applications. Herein, the intrinsic effect mechanism of SO 2 on Hg0 oxidation in the absence/presence of SCR atmosphere over the hollow nanotube CoMnTiO x was systematically investigated. It was demonstrated that SO 2 possessed a bidirectional effect on Hg0 oxidation, the facilitating effect was attributed to the production of HgSO 4 and the inhibiting effect was due to the formation of metal sulfate, which was exactly equilibrated when the deposition of sulfate on the catalyst reached 3.88 %. Interestingly, the presence of SCR atmosphere enhanced the suppression of SO 2 on Hg0 oxidation, which was caused by the fact that SO 2 + O 2 consumed partial Hg0 to form HgSO 4 , upsetting the reaction equilibrium of HgO reduction induced by SCR atmosphere and ultimately aggravating the reduction process of the already generated HgO. This work provides a new and comprehensive insight into the effect of SO 2 on Hg0 oxidation during the synergistic removal of Hg0 in SCR device, which is instructive in exploring strategies to mitigate the SO 2 poisoning. [ABSTRACT FROM AUTHOR]

Abstract: Hazardous organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) generated during the course of coal pyrolysis are highly mutagenic and carcinogenic. The relation between the amount of PAHs from the raw coal and that generated from coal pyrolysis were studied. Firstly, three Chinese coals from Huolinhe, Ximeng and Fenxi were respectively extracted by dichloromethane, and then, online pyrolysis analysis of the raw coals, their extraction residues and extracts were carried out respectively by PY (Pyro-probe CDS 5250)–GC–MS. The experimental results showed that the PAHs generated from the Huolinhe, Ximeng and Fenxi coals in the course of their pyrolysis was 523, 327 and 1707μg/g, respectively, which were much higher than the free PAHs extracted from their corresponding raw coals. The PAHs in the raw coals were dominated by 4,5-ring PAHs, while those generated from the coal pyrolysis were dominated by lower-ring (2,3-rings) PAHs. A lot of important information about the generation of PAHs from residue pyrolysis was also included in the paper which indicated that the PAHs were mainly from complex chemical reactions of the coal pyrolysis, and PAHs were more likely to be generated from the residue pyrolysis due to the increased pores that appeared on the coal surface during the course of extraction operation. [Copyright &y& Elsevier]

Abstract: The adsorption of carbon disulfide on one raw and three modified activated carbon samples at different temperatures from 303 K to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus. The amounts of carbon disulfide adsorbed by three modified carbon samples are all larger than that of the raw one. It is found that organic amine is more effective than KOH as active ingredient for modification of activated carbon. The Freundlich equation is found to be the best model to fit the isotherm data for the four carbon samples at different temperatures studied. The isosteric heats of adsorption on the four carbon samples, derived from the adsorption isotherms using the Clapeyron equation, decrease with increase of surface loading. The heat of adsorption lies between 17.7 and 51.4 kJ/mol, where the carbon sample modified with KOH and ethylenediamine has the highest value with the exception of the case of high surface coverage (>3.5 mmol/g). It is also found that the choice of adsorption isotherm has a significant influence on the values of isosteric heat of adsorption calculated. The isosteric heats of adsorption at zero surface loadings for the four carbon samples are 53.93, 53.87, 45.17 and 65.54 kJ/mol respectively and the carbon sample modified with KOH and ethylenediamine has the highest value. Analysis of the thermodynamic data shows the mobility of adsorbed carbon disulfide increases with increase of surface loading in all cases. The observed entropy change associated with the adsorption is higher than the theoretical value for the mobile adsorption but lower than the theoretical value for the localized adsorption in all cases except the carbon sample modified with KOH and ethylenediamine at higher surface coverage (>4 mmol/g). The observed entropy change also decreases with increase of surface loading in all cases. [Copyright &y& Elsevier]

Sec-hexyl acetate was synthesized by the addition-esterification of 1-hexene. The activity of zinc-exchanged phosphotungstic acid catalysts is decided by the equilibrium relationship between the two different active sites, and the Lewis acid site can improve the adsorption capacity of the catalyst for acetic acid molecules. The in-situ FT-IR spectrum experiment confirms that the reaction rate of alkene isomerization is greater than that of the addition-esterification, and a higher temperature is not conducive to the generation of acetate. [Display omitted] The addition-esterification reaction of fatty acids and alkenes is an important method for replacing the Fischer-Speier esterification due to its 100 % atomic utilization. In this study, sec -hexyl acetate was synthesized through the addition-esterification of 1-hexene. At the same time, five different zinc-exchanged phosphotungstic acid catalysts were prepared using the ion exchange method, and their catalytic activities in the addition-esterification were tested and compared. Results indicate that the Zn 0.5 H 2.0 PW- I catalyst exhibits the best performance in six different catalysts, which is attributed to the synergistic effect of Brönsted and Lewis acids. The activity of catalysts is determined by the equilibrium relationship between Brönsted and Lewis acidity. In the addition-esterification of alkenes, the main activity center is the Brönsted acid site, while the Lewis acid site can improve the adsorption capacity of the catalyst for acetic acid molecules. Moreover, the preparation methods have a significant impact on the activity of catalysts. In addition, the in-situ FT-IR spectrum experiment confirms that the reaction rate of alkene isomerization is greater than that of addition-esterification, and a higher temperature is not conducive to the generation of acetate. [ABSTRACT FROM AUTHOR]

China's growing demand for bulk chemicals and concerns regarding energy security are scaling up coal-to-olefins (CTO) production. Three generations of independent dimethyl ether/methanol-to-olefins technologies have been successively launched with greatly improved production efficiencies. However, to date, widespread concerns regarding the intensive environmental impacts and potential economic risks have not been addressed in the context of this industrialization. Here we show that, through the technological progress from the first to the third generation, life cycle energy consumption, water consumption, and carbon emissions can be reduced to 119.5 GJ/t, 27.6 t/t, and 9.1 t CO 2 -eq/t, respectively, and human health damage, ecosystem quality damage, and resource scarcity impacts can be decreased by 40.5 %, 50.1 %, and 16.4 %, respectively. This is accompanied by an excellent performance in terms of production cost, net present value, and internal return rate at 792.5 USD/t, 173.4 USD/t, and 19.4 %, respectively. Substantial environmental and economic benefits can be gained by coupling renewables in the form of using green hydrogen from solar and wind power to synthesize methanol. Particularly, life cycle carbon emissions and resource scarcity impacts are reduced by 23.4 % and 22.4 %, respectively, exceeding the reduction in technological progress. However, coupling renewables increases the life cycle energy consumption to 154.5 GJ/t, counteracting the benefits of technological progress. Our results highlight the importance of technological progress and coupled renewables for enhancing the sustainability of the CTO industry. • Four coal-to-olefins technology scenarios are compared for nine indicators. • Secondary technological progress largely increases environmental benefits. • Coupling renewables greatly mitigates carbon emissions and resource scarcity. • Coupling renewables rebounds energy use and offsets technological progress. • Technological progress and coupling renewables offer robust economic benefits. [ABSTRACT FROM AUTHOR]

Simultaneous removal of NO and Hg0 in one purification unit is cost-effective, while the conflicting redox environmental requirements remains extremely challenging. Herein, hollow nanotube Co-Mn/TiO 2 was elaborately fabricated by reconstructing nanoparticles to ameliorate the redox equilibrium, allowing the catalysts to sustain the excellent synergistic catalytic performance, which delivered more than 98 % NO x conversion with above 95 % N 2 selectivity and nearly 100 % Hg0 removal efficiency within 150–240 °C. Abundant oxygen vacancies and strong surface acidity were synchronously generated after the formation of unique hollow nanotube, improving the mobility of oxygen species and facilitating the adsorption and activation of reactants, and the cooperation of oxygen vacancy and surface acidity resulted in superior simultaneous removal activity. Strikingly, in situ DRIFTS and kinetic results revealed that the reaction rate was obviously accelerated on hollow nanotube Co-Mn/TiO 2. This study provided new insights toward engineering efficient catalysts for simultaneous removal of NO and Hg0. [Display omitted] • Hollow nanotube Co-Mn/TiO 2 was fabricated by in-situ reconstruction of nanoparticles. • The redox equilibrium of synergistic removal of NO and Hg0 was rationally ameliorated. • The efficient simultaneous removal of NO and Hg0 with desired N 2 selectivity was achieved. • The cooperation of oxygen vacancies and surface acidity resulted in the excellent performance. • The reaction rate was obviously accelerated on hollow nanotube Co-Mn/TiO 2 catalysts. [ABSTRACT FROM AUTHOR]

Recently, green ammonia has attracted growing attention due to its high energy density, environmental friendliness, and safety, and is gradually being tested or demonstrated in vehicles. However, the knowledge and understanding of the strengths and weaknesses of fuel cell electric vehicle with on-board ammonia cracking for hydrogen production and other commercially available vehicles are insufficient. This study evaluated 12 technical routes (Electricity, Gasoline, Hydrogen, Ammonia) from technical, environmental and economic perspectives and compared the comprehensive competitiveness by coupling carbon emissions, energy consumption, and costs indicators using the entropy weighting method. The results show that although the renewable energy-based technical routes reduce carbon emissions and energy consumption, they have relatively high economic costs. Considering energy consumption, carbon emissions and total costs, battery electric vehicles have the best comprehensive competitiveness at room temperature. However, ammonia-hydrogen fuel cell electric vehicles can be applied in special scenarios. Their comprehensive competitiveness is essentially equal to that of battery electric vehicles when the electric consumption of battery electric vehicles increases by more than 35 % under low temperature conditions. In addition, large-scale, long-distance transportation of ammonia is economically advantageous compared to hydrogen transportation, especially when hydrogen/ammonia is transported over distances of more than 500 km. • Compare 12 routes technically, environmentally, and economically. • Use multiple indicators for comprehensive competitiveness. [ABSTRACT FROM AUTHOR]

Adsorption desulfurization processes employing zeolites as sorbents are considered to be prospective desulfurization methods owing to their cost-effectiveness. Y zeolites modified with Cu and Ce have excellent adsorption capacity and selectivity for adsorption desulfurization. However, the effect of using different metal precursors on the active sites of these sorbents and their adsorption desulfurization performance still remains ambiguous, which impedes the development of improved desulfurization adsorbents. Herein, Cu(NO 3) 2 , Cu(Ac) 2 , and CuSO 4 were selected as Cu precursors to prepare a series of CuCeY from CeY zeolite. Desulfurization experimental results indicate that outstanding breakthrough adsorption capacities for thiophene (ca. 6.25 mg·g−1) with benzene as the solvent were achieved by the CuCeY A. The interaction between the Cu Ce metals was beneficial for enhancing the electron transfer between Cu2++Ce3+/Ce4++Cu+. Moreover, using different copper precursors significantly changed the redox ability of the adsorbent surface. Changing the copper precursor also had a significant effect on the locations of Cu and Ce ions, and using Cu(Ac) 2 as a metal precursor facilitated the migration of Cu+ (53.6%) and cerium species (35.9%) to the supercage. In situ infrared characterization showed that the oligomerization of thiophene on CuCeY A was significantly restricted due to the lowest B acid content (11.85%) in the CuCeY A. [Display omitted] • A series of CuCeY have been prepared by a variety of Cu precursors. • CuCeY A prepared using Cu(Ac) 2 exhibits the excellent desulfurization performance. • Cu(Ac) 2 as precursor affected the chemical speciations and location of Cu and Ce. • Thiophene oligomerization can be significantly restricted on CuCeY A. [ABSTRACT FROM AUTHOR]

[Display omitted] • A two-step craft was proposed to prepare Hg0 sorbent from high organic sulfur coal. • Fe 2 O 3 doping changed organic sulfur to FeS x during carbonization process. • KOH changed FeS x to various active sulfur during activation process. • This two-step craft can be expanded to other organic sulfur materials. It is a win–win strategy to prepare mercury sorbents from low-cost high-sulfur raw materials. In part 1, mercury sorbents with excellent performance were prepared from high inorganic sulfur coal through KOH activation. However, this method does not work for high organic sulfur coal. In this work, a two-step preparation method is developed to prepare mercury sorbents from high organic sulfur coal. The first step is the co-pyrolysis/carbonization of Fe 2 O 3 and coal, during which organic sulfur in coal is converted into FeS x. XPS shows that the percentage of S x 2–/S on the surface of the carbonized samples gradually increases from 5.4% to 22.2% with the m(Fe):m(S o) ratio from 0:4 to 5:4. The second step is KOH activation, and it converts FeS x into various S species, including C-S, S0, S 2 2− and S2−. Among the prepared mercury sorbents, LF+3Fe/4S-A (m(Fe):m(S o) = 3:4) shows the best mercury removal performance, and its mercury removal efficiency remains above 84% for 120 min under N 2 +O 2 at 120 °C. The Hg-TPDD and XPS results indicate that S*, including C-S, S0 and S 2 2−, are the major active sites for mercury removal rather than Fe element, and HgS is the main existing form of mercury on the used sorbents. Besides LF coal, this two-step process is also applicable to other high organic sulfur coals (such as LL coal, WJZ coal, and SY coal) and high-sulfur petroleum coke. [ABSTRACT FROM AUTHOR]

Experiments were conducted to investigate the coal gasification performance and char characteristics affected by Ca/Na compounds. Firstly, the gasification reactivities of Ca-loaded coal, Na-loaded coal, and Ca/Na-loaded coal were compared by TGA in different gasifying agents including 100% H 2 O, 100% CO 2 , and 66.7% H 2 O + 33.3% CO 2 . Then, partially-gasified chars of Ca/Na-loaded coal with carbon conversion of 50% were prepared in different gasifying agents and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption measurement. It was found that Ca together with Na showed a combined effect towards the gasification reactivity which was the most obvious in H 2 O/CO 2 mixtures, and Na could promote the synergistic effect caused by Ca catalysis at higher temperature (900 °C). Na can inhibit the agglomeration of CaO due to its excellent mobility and the formation of a eutectic mixture Na 2 Ca(CO 3 ) 2 . The marked improvement of CaO dispersion on the partially-gasified char in H 2 O/CO 2 mixtures results in the significant combined effect between Ca and Na and improves the synergistic effect at higher temperature. Moreover, the combined effect between Ca and Na during catalytic gasification can not only facilitate the gasification reactivity but also promote the development of pore structures for the gasified char. [ABSTRACT FROM AUTHOR]

In this paper, the effect of calcium on coal gasification in mixture agents containing both H 2 O and CO 2 was investigated by comparing the gasification behaviors of the demineralized coal and calcium-loaded coal using Wucaiwan (WCW), a calcium-enriched low rank coal, as the raw material. TG analysis of pure CaCO 3 was conducted at different conditions to reveal the catalytic mechanism of calcium. The properties of the chars as well as partially-gasified chars were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Moreover, pore structures of partially-gasified chars were obtained by BET analysis. It was found that under calcium catalysis, the normalized gasification rate K increased more than 20 times in H 2 O/CO 2 mixtures, and this value was much higher than that in pure H 2 O and pure CO 2 . The results suggest that under the influence of calcium, there is a synergistic effect between H 2 O and CO 2 during co-gasification when temperature is lower than 900 °C. The reason for this enhanced gasification is the fact that CaO, the main form of calcium mineral during coal catalytic gasification, can catalyze coal gasification in H 2 O/CO 2 mixtures much more effectively and create a strong synergistic effect. H 2 O can decrease the size of the CaO particles and increase their dispersity, thus facilitating CO 2 adsorption on CaO. Furthermore, with CaO participation, interaction between H 2 O and CO 2 can allow both of them to enter the interstices or pores of the coal char more rapidly, which accelerates the reaction rate and results in the synergistic effect. The synergistic effect becomes weaker as the temperature rises, which can be attributed to reduced adsorption of CO 2 on CaO and the sintering of CaO at higher temperature. [ABSTRACT FROM AUTHOR]

The key challenge for controlling Hg0 using selective catalytic reduction (SCR) technology is to develop a suitable catalyst capable of operating in a cost-effective manner, so it is necessary to study the in-depth reaction mechanism. Herein, Co-Mn/TiO 2 catalysts were fabricated by sol-gel method, excellent stability and high efficiency of Hg0 removal (100%) and NO conversion (99%) are concurrently reached at 180 °C, which are benefited from the abundant active oxygen species on the catalysts. In order to clarify the synergistic reaction process, the mechanism of mutual effects between SCR atmosphere and Hg0 is highly dedicated. Specifically, NO and O 2 were beneficial to Hg0 oxidation, while NH 3 competitive adsorption with Hg0 and consumption of active oxygen species prevent the Hg0 oxidation. Impressively, the inhibition effect of NH 3 was not weakened but also intensified, mainly due to the co-existence of NO and NH 3 could induce partial HgO reduction. What's more, the direct evidence for the synergistic reaction mechanism of NO and Hg0 is hypothesized by a combination of XPS and in-situ DRIFTs. These findings thus open up a way to address the simultaneous removal of NO and Hg0 in industry. [Display omitted] • The Co-Mn/TiO 2 catalysts exhibited superior performance for simultaneous removal of NO and Hg0. • The inhibition effect of NH 3 was not weakened but also intensified with the addition of NO. • The mutual effect between NO reduction and Hg0 oxidation and synergistic reaction mechanism were systematically reviewed. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13 C NMR) spectroscopy, and then the factors influencing the formation of PAHs during coal pyrolysis were discussed together with the coal structural data. It was shown that the amount of PAHs generated during coal pyrolysis was largely related to coal rank and followed the order of medium metamorphic coal > low metamorphic coal > high metamorphic coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during coal pyrolysis depends on the structure of the coal. The species and amounts of PAHs generated during coal pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the coal structure. [ABSTRACT FROM AUTHOR]

• The texture properties of hierarchical TS-1 zeolites can be precisely modulated by the TritonX homologues with different amounts of ethoxide. • The mesoporosity and Ti content of hierarchical Ti-rich determine the conversion of benzene. • Introducing additional mesoporosity into the hierarchical TS-1 facilitates the direct the oxidation of benzene. The hydrothermal approach was used to effectively synthesis hierarchical TS-1 utilizing the green and inexpensive surfactant TritonX homologues with varying amounts of ethylene oxide groups. The textural property of obtained materials can be modulated by varying the number of ethylene oxide groups of the TritonX homologues. The mesoporous size of hierarchical TS-1 depends on the micelles size of TritonX homologues. The synthesized samples have significant intracrystalline mesopores with a pore size range of 3.5–4.5 nm. The impact of various ethylene oxide group counts of TritonX homologous on the structure, texture properties, and titanium species was investigated using a variety of characterization methods. The hydroxylation of benzene with the H 2 O 2 as oxidizer was used to investigate the catalytic properties of hierarchical TS-1. The catalytic properties and stability of the resulting materials were noticeably improved in the hydroxylation of benzene in comparison with the traditional TS-1. [Display omitted] [ABSTRACT FROM AUTHOR]

A gas coal (B) was used to study the effect of volatiles on sulfur removal from a high organic-sulfur coking coal (A) from the perspective of mass transfer conditions. The mass transfer driving force and resistance of volatiles were analyzed in terms of fluidity development, permeability of coal plastic stage to gas flow, and volatile matter release. Carbonization using vertical and horizontal stacking modes of two coals were designed according to the release directions of volatiles during pyrolysis. Three pyrolysis temperatures (450, 475 and 510 ºC) were used to study mass transfer conditions. The semicokes were cut into pieces at fixed intervals along vertical and horizontal directions to determine the spatial sulfur distribution in semicoke. The gas coal volatiles helped the removal of sulfur within a limited distance that was related to the mass transfer conditions of volatiles, whereas permeability determined the mass transfer resistance of volatiles and their driving force was controlled by the amount and rate of volatile matter release. • Mass transfer conditions of volatiles vary with permeability of A and volatile evolution of B. • Volatiles of B remove sulfur within effective distances in vertical and horizontal directions. • Favorable mass transfer conditions extend release distance but reduce the reaction time. • Low permeability of plastic stage of A makes sulfur removal gentle but continuous. [ABSTRACT FROM AUTHOR]

In this work, we investigated the effect of Cu doping on the energetic, structural, and electronic properties of (ZnCu)(OH)(CO) (0 ≤ x ≤ 0.5) by density functional theory (DFT). Our calculation results demonstrate that (ZnCu)(OH)(CO) is the most stable structure in thermodynamics. Cu atoms prefer to occupy Zn + Zn + 2Zn sites in the case of x = 0.4. The calculated equilibrium lattice constants and average bond lengths agree well with the available experimental results. With increasing the amounts of Cu dopant (0.1 ≤ x ≤ 0.4), the covalent features of Cu-doped Zn(OH)(CO) systems are gradually weakened, while the Cu site exhibits the strongest Jahn-Teller distortion. Besides, the calculated population analysis illuminates the variation of -OH infrared stretching vibration frequency and the thermal decomposition order of CO. The TDOS curve of (ZnCu)(OH)(CO) shifts to the lower energy region than other systems, confirming its thermodynamic stability. Moreover, hydrogen locations are determined by performing structural optimization using DFT. These derived computational findings of (ZnCu)(OH)(CO) are expected to help improve our fundamental understanding of improving the Cu/ZnO catalysts. [ABSTRACT FROM AUTHOR]

The ethylbenzene dehydrogenation and the oxidation ability of CO 2 on the V 2 O 5 (001) surface are systematically studied by the density functional theory method. Results show that among all three lattice oxygen sites on V 2 O 5 (001): the vanadyl oxygen O(1), the bridge oxygen O(2), and the three-coordinate oxygen O(3), the O(1) site is the active site for the ethylbenzene dehydrogenation. With the production of styrene, the lattice oxygen O(1) is removed by H 2 O release. As a soft oxidant, CO 2 cannot re-oxidize the defected V 2 O 5 (001) in time due to the relatively high activation energy, which gradually leads to the deactivation of the catalyst. [ABSTRACT FROM AUTHOR]

Abstracts A considerable amount of organic compounds could be released during coal utilization processes, and these compounds could have a significant detrimental effect on the environment and human health if freely discharged. In this study, we investigated the yields of two organic compounds (PAHs and phenols) released during the pyrolysis of coals with different ranks. And then, the formation mechanisms of PAHs and phenols are discussed by means of comparisons the correlation between release principles and coal structure. The results showed that the yields of PAHs and phenols depended to a large extent on coal structure. PAHs are formed not only by thermal breakdown of coal structure, but also by the combination of different low molecule weight compounds with each other. Monohydric phenolic carbon and aromatic ether carbon were likely to be the precursor structure of phenols. The formation of phenol, cresol and xylenol are closely related to the types of free radical (like H or CH 3 ) and the chemical structure of oxygenated aromatic carbon in coal during pyrolysis. [ABSTRACT FROM AUTHOR]

Ni-Ce/γ-Al 2 O 3 catalysts were prepared by traditional and microwave heating and tested by the methanation of simulated coke oven gas in a fixed bed reactor. Various characterization techniques were used to examine the bulk and surface properties of the catalysts. The catalysts obtained by microwave heating show superior methanation activity to traditional catalysts. Conversion of 100% CO, CO 2 , and O 2 , with part conversion of C 2 H 6 , was obtained on the MO-15NC catalyst with the following reaction conditions: 260 °C, 3.0 MPa and 20,000 mL g −1 h −1 weight hourly space velocity. The temperature gradient between the NiO and the alumina support caused by the difference in microwave energy absorption promotes the formation of a large amount of highly dispersed amorphous NiO with a Ni loading of less than 15 wt%, and is more active for the methanation reaction because of a weak interaction with the support, large active surface area and low CO dissociation energy. [ABSTRACT FROM AUTHOR]

Interactions between feedstocks during pyrolysis of coal–biomass blends, and their impacts on product distribution and conversion behavior during utilization, need to be understood if we are to successfully develop systems for the effective co-utilization of biomass and coal. A novel two-stage fixed-bed reactor containing three quartz tubes was designed and used in this study to investigate these interactions, with particular emphasis on the impact on product distribution and char properties. The results show that interactions exist during co-pyrolysis of corncob and lignite blends, which increase overall tar yields and decrease overall gas yields compared with those obtained from pyrolysis of unblended feedstocks, with the interactions between corncob volatiles and lignite playing a dominant role. It is also shown that interactions between chars and volatiles can impact on the reactivity of chars to O 2 . Consistent with our expectations, there is a link between potassium content in char and its reactivity; however, it is found that for lignite chars in particular the potential impact of potassium is dominated by the changes of char chemical structure. The effect of potassium content is the opposite to that of char chemical structure, leading to significant complexity in determining the net result of any co-pyrolysis interactions on char reactivity. This highlights the importance of understanding these complex interactions to develop the industrial scale co-gasification systems and adjust the distributions of products. [ABSTRACT FROM AUTHOR]

The structural features and gasification reactivity of chars derived from pyrolysis of a bituminous coal under Ar (Ar char) and CO 2 atmosphere (CO 2 char) have been investigated, respectively. The pyrolysis was performed in a fixed bed reactor at a final temperature of 700 °C and pressures ranging from 0.1 to 1.5 MPa. It was found that CO 2 affect the char yield, pore structure and surface area. The N 2 surface area of the CO 2 char at ambient pressure increased by nearly 42 times compared to the Ar char. The chemical structure features were characterized by using Raman spectroscopy. The recorded spectra between 800 and 1800 cm −1 were curve-fitted with 10 Gaussian bands representing typical structural features of chars to quantitatively compare the char structure difference. The ratio I ( G r + V l + V r ) / I D between the band intensities of amorphous char structures with small aromatic ring (3–5 rings) systems and condensed aromatic ring systems (>6 rings) is seen to decrease with increasing pyrolysis pressure. The I ( G r + V l + V r ) / I D of CO 2 char is always lower than that of Ar char in the whole pressure range. The non-isothermal CO 2 gasification from 700 to 1000 °C in a TGA (thermogravimetric analyzer) indicates that the char prepared under Ar atmosphere was more reactive. [ABSTRACT FROM AUTHOR]

Highlights: [•] CO2 utilization as gasifying agent during H2O-char gasification was studied. [•] Synergy was revealed during coal gasification with CO2/H2O mixture in low temperature. [•] The high catalytic activity of Ca species in CO2 gasification leads to the synergy. [ABSTRACT FROM AUTHOR]

• An assessment framework integrating LCA, TEA, and EW is proposed. • The CBFE and SGFB routes are considered competitors of the FGFB route in China. • The SGFB route scores the greatest comprehensive competitiveness. • The CBFE route performs better in economic benefit at the current prices. The world's first industrialized coal-based fuel ethanol (CBFE) and emerging second-generation fuel bioethanol (SGFB) routes are promising alternatives and potential competitors to the conventional first-generation fuel bioethanol (FGFB) route. Understanding the comprehensive competitiveness of the three fuel ethanol production routes is important for the development of clean and low-carbon transportation worldwide. However, there is currently a dearth of related knowledge and scientific data. In this study, we identified and compared the strengths and weaknesses of the three fuel ethanol production routes using an assessment framework that integrates life cycle assessment, techno-economic analysis, and entropy weight method. Environmental performance was investigated with the 18 midpoint impact categories of the ReCiPe 2016 method and modeled using the SimaPro software. Economic performance was represented using the net present value, dynamic payback period, and internal rate of return. The results demonstrated the highest comprehensive score in the SGFB route owing to its excellent environmental performance, which will likely address the unsustainability of the FGFB route through the efficient utilization of agricultural residuals. Owing to its considerable economic benefit, the industrialization of the CBFE route not only offers a new downstream chain in the coal industry but also diversifies the sources of fuel ethanol away from biomass. However, such a promising alternative faces a substantial challenge associated with its significant environmental impact, especially with its high greenhouse gas emissions. These results provide valuable information on the relative advantages and disadvantages of the CBFE, FGFB, and SGFB routes for scientific tradeoffs and decisions. [ABSTRACT FROM AUTHOR]