传统水泥工业不可持续发展的因素与中国水泥工业可持续发展的对策

如何及早认识,采取有力措施,发扬水泥工业有利的一面,克服水泥工业不利的一面,为人类的可持续发展服务,为人类造福,这是世界可持续发展工商理事会（WBCSD）和中国企业联合会（CEC）联合举办“面向可持续发展的水泥工业专题研讨会”的主题,在资源、能源、环境等三个方面存在着制约传统水泥工业不可持续发展的因素,提出了实现水泥工业可持续发展的7点对策。     

The simultaneous activation of methane and carbon dioxide to C2 hydrocarbons under pulse corona plasma over La2O3/γ-Al2O3 catalyst

The pulse corona plasma has been used as an activation method for reaction of methane and carbon dioxide, the product was C₂ hydrocarbons and by-products were CO and H₂. Methane conversion and the yield of C₂ hydrocarbons were affected by the carbon dioxide concentration in the feed. The conversion of methane increased with increasing carbon dioxide concentration in the feed whereas the yield of C₂ hydrocarbons decreased. The synergism of La₂O₃/γ-Al₂O₃ and plasma gave methane conversion of 24.9% and C₂ hydrocarbons yield of 18.1% were obtained at the power input of plasma was 30 W. The distribution of C₂ hydrocarbons changed by using Pd-La₂O₃/γ-Al₂O₃ catalyst, the major C₂ product was ethylene.     

Catalytic activation of CO2: Use of secondary CO2 for the production of synthesis gas and for methanol synthesis over copper-based zirconia-containing catalysts

Consumption of fossil fuel resources throughout the industrial era has resulted in an enormous increase in carbon dioxide concentration in the atmosphere. Developed countries have committed to reducing the atmospheric load of greenhouse gases and ratified the Kyoto Protocol. Chemical utilization of carbon dioxide captured from large scale stationary sources is one possible pathway to decrease the rate of emissions. Catalysis plays a crucial role in these carbon dioxide utilization reactions. In this paper, the production of synthesis gas from carbon dioxide-containing secondary gases and carbon dioxide hydrogenation to methanol over copper-based zirconia-containing catalysts have been investigated. Pathways of carbon dioxide utilization are outlined, research done on carbon dioxide hydrogenation over copper-based zirconia-containing catalysts is reviewed, and the challenges of these reactions are reported. It is argued that direct utilization of secondary carbon dioxide from industrial sources can be a significant step toward developing sustainable industrial practices and a critical part in sustainable energy strategies.     

Promoting effects of CO2 on dehydrogenation of propane over a SiO2-supported Cr2O3 catalyst

The effects of carbon dioxide on the dehydrogenation of C₃H₈ to produce C₃H₆ were investigated over several Cr₂O₃ catalysts supported on Al₂O₃, active carbon and SiO₂. Carbon dioxide exerted promoting effects only on SiO₂-supported Cr₂O₃ catalysts. The promoting effects of carbon dioxide over a Cr₂O₃/SiO₂ catalyst were to enhance the yield of C₃H₆ and to suppress the catalyst deactivation.     

Energy saving in a CO2 capture plant by MEA scrubbing

The most commonly used process for the CO₂ capture is absorption by means of chemical solvents such as alkanolamines. This consolidated technology can be applied to CO₂ removal from natural gas, refinery gas, and exhaust gas of power plants.This paper focuses on CO₂ capture from exhaust gas by absorption with monoethanolamine (MEA).A commercial simulation software, namely Aspen Plus^®, is used, with Electrolyte-NRTL thermodynamic package where ad hoc parameters, obtained from regression of experimental solubility data for the system CO₂-MEA-H₂O, have been implemented.The comparison among different schemes is based on energy saving. Both the reboiler heat duty and the total equivalent work (which sums up every work and heat contribution in the purification section) are considered as criteria for comparison.     

Utilization of carbon dioxide as soft oxidant for oxydehydrogenation of ethylbenzene to styrene over V2O5–CeO2/TiO2–ZrO2 catalyst

Vanadium oxide and cerium oxide doped titania–zirconia mixed oxides were explored for oxidative dehydrogenation of ethylbenzene to styrene utilizing carbon dioxide as a soft oxidant. The investigated TiO₂–ZrO₂ mixed oxide support with high specific surface area (207 m² g⁻¹) was synthesized by a coprecipitation method. Over the calcined support (550 °C), a monolayer equivalent (15 wt.%) of V₂O₅, CeO₂ or a combination of both were deposited by using wet-impregnation or co-impregnation methods to make the V₂O₅/TiO₂–ZrO₂, CeO₂/TiO₂–ZrO₂ and V₂O₅–CeO₂/TiO₂–ZrO₂ combination catalysts, respectively. These catalysts were characterized using X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM), temperature preprogrammed reduction (TPR), CO₂ temperature preprogrammed desorption (TPD) and BET surface area methods. All characterization studies revealed that the deposited promoter oxides are in a highly dispersed form over the support, and the combined acid–base and redox properties of the catalysts play a major role in this reaction. The V₂O₅–CeO₂/TiO₂–ZrO₂ catalyst exhibited a better conversion and product selectivity than other combinations. In particular, the addition of CeO₂ to V₂O₅/TiO₂–ZrO₂ prevented catalyst deactivation and helped to maintain a high and stable catalytic activity.     

Activity of carbided molybdena–alumina for CO2 hydrogenation

The relationship between the catalytic activity of carbided molybdena–alumina and the methane desorption from carbidic carbon through temperature-programmed surface reaction (TPSR) were studied. The effects of passivation and hydrogen treatment on the catalytic activities of molybdenum carbides for CO₂ hydrogenation were determined. When the 973 K-carbided catalyst was reduced at 773 K with hydrogen, the catalyst exhibited the highest activity for the reaction, the activity decreasing with increasing H₂ pretreatment temperature. Passivation of this catalyst decreased the reaction rate by 20%. TPSR results were correlated with the activity to reveal that molybdenum carbide with slightly deficient carbidic carbon (Mo₂C_0.962C_1.0) serves as an active site for CO₂ hydrogenation.     

Hydrocarbon synthesis from CO2 over Fe–Cu catalysts

Hydrocarbons and carbon monoxide were produced from carbon dioxide and hydrogen at 400°C over copper-promoted iron catalysts containing sodium. The major surface phases of the catalysts were FeO and/or FeCO₃ although iron carbide is believed as an active phase of the hydrocarbon synthesis from carbon monoxide. Copper was present as metal on the surface and the surface density was considerably high even if the content of copper was less than 1 wt%. The surface density of sodium was not negligible in the catalysts containing sodium less than 0.1 wt% and the sodium ion can affect the surface basicity of the catalysts. The olefin content in the products is believed to relate to the surface basicity.     

开发二氧化碳资源推进碳的循环利用

地球上资源有限,而二氧化碳资源十分丰富,二氧化碳在大气中的增加会产生温室效应,开发利用二氧化碳,大力发展二氧化碳产业,具有很大的资源利用和环保意义。本文对近期二氧化碳开发利用的进展作了介绍,并对如何发展二氧化碳产业提出了建议。     

CO2 reforming of CH4 over stabilized mesoporous Ni-CaO-ZrO2 composites

Mesoporous Ni-CaO-ZrO₂ nanocomposites with high thermal stability were designed and employed in the CO₂/CH₄ reforming. The nanocomposites with appropriate Ni/Ca/Zr molar ratios exhibited excellent activity and prominent coking resistivity. The Ni crystallites were effectively controlled under the critical size for coke formation in such nanocomposites. It was found that low Ni content resulted in high metal dispersion and good catalytic performance. Moreover, the basicity of the matrices improved the chemisorption of CO₂ and promoted the gasification of deposited coke on the catalyst.     

Separation of CO2 from flue gas using electrochemical cells

Past research with high temperature molten carbonate electrochemical cells has shown that carbon dioxide can be separated from flue gas streams produced by pulverized coal combustion for power generation. However, the presence of trace contaminants, i.e., sulfur dioxide and nitric oxides, will impact the electrolyte within the cell. If a lower temperature cell could be devised that would utilize the benefits of commercially-available, upstream desulfurization and denitrification in the power plant, then this CO₂ separation technique can approach more viability in the carbon sequestration area. Recent work has led to the assembly and successful operation of a low temperature electrochemical cell. In the proof-of-concept testing with this cell, an anion exchange membrane was sandwiched between gas-diffusion electrodes consisting of nickel-based anode electrocatalysts on carbon paper. When a potential was applied across the cell and a mixture of oxygen and carbon dioxide was flowed over the wetted electrolyte on the cathode side, a stream of CO₂ to O₂ was produced on the anode side, suggesting that carbonate/bicarbonate ions are the CO₂ carrier in the membrane. Since a mixture of CO₂ and O₂ is produced, the possibility exists to use this stream in oxy-firing of additional fuel.From this research, a novel concept for efficiently producing a carbon dioxide rich effluent from combustion of a fossil fuel was proposed. Carbon dioxide and oxygen are captured from the flue gas of a fossil-fuel combustor by one or more electrochemical cells or cell stacks. The separated stream is then transferred to an oxy-fired combustor which uses the gas stream for ancillary combustion, ultimately resulting in an effluent rich in carbon dioxide. A portion of the resulting flow produced by the oxy-fired combustor may be continuously recycled back into the oxy-fired combustor for temperature control and an optimal carbon dioxide rich effluent.     

CO2 reforming of CH4 over nanocrystalline zirconia-supported nickel catalysts

Mesoporous nanocrystalline zirconia with high-surface area and pure tetragonal crystalline phase has been prepared by the surfactant-assisted route, using Pluronic P123 block copolymer surfactant. The synthesized zirconia showed a surface area of 174 m² g⁻¹ after calcination at 700 °C for 4 h. The prepared zirconia was employed as a support for nickel catalysts in dry reforming reaction. It was found that these catalysts possessed a mesoporous structure and even high-surface area. The activity results indicated that the nickel catalyst showed stable activity for syngas production with a decrease of about 4% in methane conversion after 50 h of reaction. Addition of promoters (CeO₂, La₂O₃ and K₂O) to the catalyst improved both the activity and stability of the nickel catalyst, without any decrease in methane conversion after 50 h of reaction.     

CO2 sequestration from coal fired power plants

The paper takes into consideration a new approach for CO₂ capture and transport, based on the formation of solid CO₂ hydrates.Carbon dioxide sequestration from power plants can take advantage of the properties of gas hydrates. The formation and decomposition of hydrates from various N₂-CO₂ mixtures has been studied experimentally in a 2 l reactor, to determine the CO₂ separation in terms of hydrate composition and residual CO₂ content in the reacted gas.Carbon dioxide acts as a co-former for the production of hydrates containing nitrogen, besides CO₂. The mixed hydrates that are obtained are less stable than simple CO₂ hydrates. When CO₂ content in the flue gas is higher than 30% by volume, the hydrates formed at 5 MPa are sufficiently concentrated (about 70% CO₂) and carbon dioxide reduction in the reacted gas is acceptable.The application of a process based on hydrate formation could be especially interesting (for CO₂ capture and transport) when connected to an oxy-coal combustion process; in this case the CO₂ content in the flue gas is very high and the hydrate formation is greatly facilitated.     

“动态超分子”假说预测烷烃吸收CO2相平衡

采用“动态超分子假说”对烷烃吸收CO₂相平衡进行了研究,并结合最小二乘法和试算对烷烃数据进行拟合,得到相关参数,拟合值和文献实验值的线性相关度均大于0.95,符合良好。研究表明,烷烃分子之间形成的同种“动态超分子”对吸收过程影响较大,远远大于CO₂同种超分子和溶剂与CO₂之间形成的异种超分子,而且其随着烷烃碳链增加,“动态超分子”形成概率和稳定性均降低,吸收能力逐渐增强。文中还研究了模型参数对拟合结果的影响,及其最佳取值范围。     

Dispersion polymerization of styrene in CO2-expanded ethanol

Dispersion polymerization of styrene has been performed in CO₂-expanded ethanol at ≤9 MPa and 70 °C using PVP as stabilizer. The polymerizations proceeded with good colloidal stability, resulting in spherical particles of diameters of ∼2 μm. Pressurization with CO₂ leads to an increase in particle size (∼1 μm in the corresponding CO₂-free system), and a decrease in both polymerization rate and molecular weight. The main effect of CO₂ is proposed to be its influence on the partitioning of monomer between the continuous and the particle phase–the results indicate that CO₂-pressurization causes a reduction in monomer concentration in the particles. Overall, the results are consistent with literature data on the effects of the polarity of the continuous phase in dispersion polymerization of styrene in alcohols and alcohol/water mixtures.     

Effect of methanol addition on water–CO2–diethanolamine system: Influence on CO2 solubility and on liquid phase speciation

The aim of this study is the characterisation of VLE and chemical equilibria for the system CO₂/diethanolamine (DEA)/H₂O/methanol. The effect of MeOH composition has been studied using four compositions (from 0 to 30 wt% of methanol with a fixed composition (30 wt%) of DEA), the measurement being made at T = 298.15 K and at various CO₂ loadings (from 0.2 to 0.8). An original experimental device was used. This device combines a FT-IR spectroscopy analysis of the liquid phase with a VLE measurement cell.The data base obtained, including the new solubility data and the liquid phase composition, allows the modelling of the system CO₂/DEA/H₂O/methanol using an electrolyte equation of state [Fürst, W., Renon, H., 1993, Representation of excess properties of electrolyte solutions using a new equation of state, AIChE J, 39(2): 335–343] representing the equilibrium properties of the system and the liquid phase speciation.     

Investigation of a Ba0.5Sr0.5Co0.8Fe0.2O3−δ based cathode SOFC: II. The effect of CO2 on the chemical stability

The effect of carbon dioxide on the chemical stability of a Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ cathode in the real reaction environment at 450 °C was investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), temperature programmed desorption (TPD), X-ray diffraction (XRD) and electrochemical impedance spectra (EIS) techniques. It was found that the presence even of very small quantities of CO₂ seriously deteriorates the fuel cell performance at 450 °C. XPS, TPD and XRD results strongly evidenced the formation of carbonates involving strontium and possibly barium after the BSCF cathode was operated in 1% CO₂/O₂ gas mixture at 450 °C for 24 h. SEM-EDX analysis of the BSCF cathode surface, after treatment in CO₂/O₂ environment at 450 °C, showed small particles on the surface probably associated with a carbonate phase and a segregated phase of the perovskite. The corresponding EDX spectra confirmed the presence of a carbonate layer and also revealed the surface enrichment of strontium and barium elements. EIS results indicated that both ohmic and polarization resistances increased gradually with the introduction of carbon dioxide in the oxidant stream, which could be interpreted by the decreased oxygen reduction kinetics and the formation of carbonate insulating layer.     

Fabrication of highly sensitive MnO2/F-MWCNT/Ta hybrid nanocomposite sensor with different MnO2 overlayer thickness for H2O2 detection

In this work, we report the development of MnO₂/F-MWCNT/Ta hybrid nanocomposite sensor with different MnO₂ overlayer thickness for the detection of H₂O₂ in real samples. A novel two-step process using e-beam evaporation and spray pyrolysis deposition was adopted for the synthesis of hybrid MnO₂/F-MWCNT/Ta electrodes. SE morphology revealed smaller-sized, compact grains of MnO₂ infiltrated on the outermost walls of MWCNTs. Raman analysis confirmed the existence of carbon nanotubes with abundant structural defects of MnO₂ in the composite. The cyclic voltammetry results displayed a high peak current and narrowed over potential towards the reduction of H₂O₂. The sensor displayed a fast response (<5?s), wide linear range (2–1510?μM) and a low limit of detection (0.04?μM) with significant anti-interfering properties, promising for the development of highly sensitive and reproducible biosensors. The three dimensional nanocomposite sensor also exhibited good recovery (> 98%), thus providing a favourable tool for analysis of H₂O₂ in milk samples.     

Partial oxidation of methane to CO and H2 over nickel and/or cobalt containing ZrO2, ThO2, UO2, TiO2 and SiO2 catalysts

The influence of different metal oxide supports (i.e. ZrO₂, ThO₂, UO₂, TiO₂ and SiO₂) on the performance of Ni- and/or Co-containing catalysts [Ni and/or Co/MO₂ mole ratio (where M=Zr, Th, U, Ti or Si)=1.0] in the oxidative methane-to-syngas conversion at very low contact time (GHSV=5.2×10⁵ cm³ g⁻¹ h⁻¹ at STP) was investigated. The nickel-containing ZrO₂, ThO₂ and UO₂ catalysts (with or without pre-reduction by hydrogen at 500°C) showed good performance in the process; the order of their performance is NiO–ThO₂>NiO–UO₂>NiO–ZrO₂. The NiO–TiO₂ showed appreciable catalytic activity only after its reduction at 800°C. However, this catalyst and the NiO–SiO₂ catalyst showed poor performance in the process. These two catalysts are also deactivated very fast, mostly because of sintering of Ni and/or formation of catalytically inactive binary metal oxide phases by solid–solid reaction at the high catalyst calcination and/or catalytic reaction temperature. Although the Ni-containing ThO₂, UO₂ and ZrO₂ catalysts showed good performance, carbon deposition on them during the process is fast. However, because of the addition of cobalt to these catalysts (with Co/Ni=1.0), the rate of carbon deposition on them in the process is drastically reduced. This Co addition however resulted in a significant decrease in both the conversion and selectivity; the decrease in the selectivity was small.     

Absorption of CO2 and subsequent viscosity reduction of an acrylonitrile copolymer

Acrylonitrile (AN) copolymers (AN content greater than about 85 mol%) are traditionally solution processed to avoid a cyclization and crosslinking reaction that takes place at temperatures where melt processing would be feasible. It is well known that carbon dioxide (CO₂) reduces the glass transition temperature (T_g) and consequently the viscosity of many glassy and some semi-crystalline thermoplastics. However, the ability of CO₂ to act as a processing aid and permit processing of thermally unstable polymers at temperatures below the onset of thermal degradation has not been explored. This study concentrates on the ability to plasticize an AN copolymer with CO₂, which may ultimately permit melt processing at reduced temperatures. To facilitate viscosity measurements and maximize the CO₂ absorption, a relatively thermally stable, commercially produced AN copolymer containing 65 mol% AN was investigated in this research. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that CO₂ significantly absorbs into and reduces the T_g of the AN copolymer. Pressurized capillary rheometry indicated that the magnitude of the viscosity reduction is dependent on the amount of absorbed CO₂, which correlates directly to the T_g reduction of the plasticized material. Up to a 60% viscosity reduction was obtained over the range of shear rates tested for the plasticized copolymer containing up to 6.7 wt% CO₂ (31 °C T_g reduction), corresponding to as much as a 30 °C equivalent reduction in processing temperature. A Williams-Landel-Ferry (WLF) analysis was used to estimate the viscosity reduction based on the T_g reduction (and corresponding amount of absorbed CO₂) in the plasticized AN copolymer, and the predicted viscosity reduction based on using the universal constants was 34-85% higher than measured, depending on the amount of absorbed CO₂. Van Krevelen's empirical solubility relationships were used to calculate the expected absorbance levels of CO₂, and found to be highly dependent on the choice of constants within the statistical ranges of error of the Van Krevelen relationships.