低温液体粗氩泵平稳倒换方法的探索

低温液体粗氩泵是现在空分装置氩系统中必不可少的设备。为确保该设备运行的稳定性、安全性，需定期进行倒换、检修、维护，然而该设备的倒换操作稍有不慎，则会影响空分系统的正常运行，从而造成效益损失。因此行业内许多空分生产厂家为确保短期内空分生产的稳定．而不敢于尝试对粗氩泵进行定期倒换，也因此无法保证该设备的正常定修与维护，使得空分设备的稳定性、安全性下降。

某建材矿山二氧化碳爆破技术应用

同传统的炸药爆炸做功不同,二氧化碳爆破技术具有爆破过程不产生火花、有害气体,爆破振动小等诸多优点,越来越成为高瓦斯煤矿、有降振要求的小规模基建开挖、拆除爆破等工程项目的新选择.以某建材矿山为例,介绍了二氧化碳爆破原理及应用实例,简述了孔网参数设置、爆破网路设计、施工注意事项及经济性等内容.通过与传统爆破对比,二氧化碳爆破技术振动小、无污染、安全可控,效果、效益良好,符合绿色矿山建设需要,具有一定的推广价值,并对其技术改进和应用前景进行了展望.

Influences of the [Co^2＋]/[Co^3＋] Ratio on the Process of Liquid-phase Oxidation of Toluene by Air

Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2O as catalyst.The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance.The results showed that [Co3+] reached the maximum at about 25-30min.[Co3+] increased with increasing Co catalyst amount at total Co concentration<150 mg.L-1 of toluene.The conversion of toluene,yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+] max.A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.

An Axial Dispersion Model for Evaporating Bubble Column Reactor

Evaporating bubble column reactor (EBCR) is a kind of aerated reactor in which the reaction heat is removed by the evaporation of volatile reaction mixture. In this paper, a mathematical model that accounts for the gas-liquid exothermic reaction and axial dispersions of both gas and liquid phase is employed to study the performance of EBCR for the process of p-xylene(PX) oxidation. The computational results show that there are remarkable concentration and temperature gradients in EBCR for high ratio of height to diameter (H/DT). The temperature is lower at the bottom of column and higher at the top, due to rapid evaporation induced by the feed gas near the bottom. The concentration profiles in the gas phase are more nonuniform than those (except PX) in the liquid phase, which causes more solvent burning consumption at high H/DT ratio. For p-xylene oxidation, theo ptimal H/DT is around 5.

Desulfurization of liquid hydrocarbon fuels via Cu_2O catalyzed photooxidation coupled with liquid–liquid extraction

By combining the photochemical reaction and liquid–liquid extraction(PODS), we studied desulfurization of model fuel and FCC gasoline. The effects of air flow, illumination time, extractants, volume ratios of extractant/fuel, and catalyst amounts on the desulfurization process of PODS were analyzed in detail. Under the conditions with the air as oxidant(150 ml·min^(-1)), the mixture of DMF–water as extractant(the volume ratio of extractant/oil of 0.5) and photo-irradiation time of 2 h, the sulfur removal rate reached only 42.63% and 39.54% for the model and FCC gasoline, respectively. Under the same conditions, the sulfur removal rate increased significantly up to79% for gasoline in the presence of Cu_2O catalyst(2 g·L^(-1)). The results suggest that the PODS combined with a Cu_2O catalyst seems to be a promising alternative for sulfur removal of gasoline.

Synthesis of Petroleum Sulfonate Surfactant by Different Sulfonating Agent with Application of HIGEE Technology

With the application of HIGEE process intensification technology, petroleum sulfonate surfactant used for enhanced oil recovery was synthesized from petroleum fraction of Shengli crude oil with three sulfonating agents, including diluted liquid sulfur trioxide, diluted gaseous sulfur trioxide and fuming sulfuric acid. For each sulfonating agent, different operation modes (liquid-liquid or gas-liquid reaction with semi-continuous or continuous operation) were applied. The effects of various experimental conditions, such as solvent/oil mass ratio, sulfonating agent/oil mass ratio, gas/liquid ratio, gas concentration, reaction temperature, rotating speed, circulation ratio, reaction time and aging time, on the content of active matter and unsulfonated oil were investigated. Under relatively optimal reaction conditions, the target product was prepared with high mass content of active matter (up to 45.3%) and extremely low oil/water interfacial tension (4.5×10 –3 mN·m –1 ). The product quality and process efficiency are higher compared with traditional sulfonation technology.

Determination of the gas compositions for direct coal liquefaction by gas chromatography

Via multi-dimensional gas chromatography, configured with parallel dual-channel, double detectors, valves switching and back flushing, rapid analysis of the gas compositions consisting of C1-C5 hydrocarbons and permanent gases, such as CO2, H2S, H2, and CO, for direct coal liquefaction has been realized. With four packed chromatographic columns, which are Hayesep-Q pre-column, Hayesep-Q column, molecular sieve 5A column and one PLOT A1203 S capillary column, the gas compositions for direct coal liquefaction are analyzed qualitatively and quantitatively by the external standard method. The determination method has such advantages as excellent separation, simple operation, rapid analysis and accurate results.

Axial Liquid Dispersion in Gas-Liquid-Solid Circulating Fluidized Bed

The effects of liquid viscosities, solid circulating rates, liquid and gas velocities and phase holdups on the axial dispersion coefficient, Dax, were investigated in a gas-liquid-solid circulating fluidized bed (GLSCFB).Liquid viscosity promotes the axial liquid backmixing when solid particles and gas bubbles are present. Increases in gas velocities and solid circulating rates lead to higher Dax. The effects of liquid velocity on Dax are associated with liquid viscosity. Compared with conventional expanded beds, the GLSCFBs hold less axial liquid dispersion,approaching ideal plug-flow reactors.

Permeability and Selectivity of Sulfur Dioxide and Carbon Dioxide in Supported Ionic Liquid Membranes

Permeabilities and selectivities of gases such as carbon dioxide （CO2）, sulfur dioxide （SO2）, nitrogen （N2） and methane （CH4） in six imidazolium-based ionic liquids （[emim][BF4], [bmim][BF4], [bmim][PF6], [banim][BF4], [bmim][Tf2N] and [emim][CF3SO3]） supported on polyethersulfone microfiltration membranes are investigated in a single gas feed system using nitrogen as the environment and reference component at temperature from 25 to 45℃ and pressure of N2 from 100 to 400 kPa. It is found that SO2 has the highest permeability in the tested supported ionic liquid membranes, being an order of magnitude higher than that of CO2, and about 2 to 3 orders of magnitude larger than those of N2 and CH4. The observed selectivity of SO2 over the two ordinary gas components is also striking. It is shown experimentally that the dissolution and transport of gas components in the supported ionic liquid membranes, as well as the nature of ionic liquids play important roles in the gas permeation. A nonlinear increase of permeation rate with temperature and operation pressure is also observed for all sample gases. By considering the factors that influence the permeabilities and selectivities of CO2 and SO2, it is expected to develop an optimal supported ionic liquid membrane technology for the isolation of acidic gases in the near future.

Effects of impingement and friction of swirling air stream on prefilming airblast atomization of non-Newtonian fluids

Liquids to be broken up using a prefilming airblast atomizer are usually Newton liquids with relatively low viscosities.While in some industrial processes,such as spray drying,liquids to be atomized are high concentration suspensions or non-Newtonian fluids with high viscosities.In this paper,non-Newtonian fluids with viscosity up to 4.4 Pa·s were effectively atomized using a specially designed prefilming airblast atomizer.The atomizer enabled liquid to extend to a thickness-adjustable film and forced the atomizing air stream to swirl with 30° or 45° through gas distributors with spiral slots.The liquid film was impinged by the swirling air stream resulting in the disintegration of the film into drops.Drop sizes were measured using a laser diffraction technique.An improved four-parameter mathematical model was established to relate the Sauter mean diameter of drops to the atomization conditions in terms of power dependencies on three dimensionless groups:Weber number,Ohnesorge number and air liquid mass ratio.The friction on the surface of the liquid film made by swirling air stream played an important role in the prefilming atomization at the conditions of low air velocity and low liquid viscosity.In this case,the liquid film was disintegrated into drops according to the classical wavy-sheet mechanism,thus thinner liquid films and high swirl levels of the atomizing air produced smaller drops.With the increase of the air velocity and the liquid viscosity,the effect of the friction on the prefilming atomization relatively weakened,whereas the impingement on the liquid film made by atomizing air stream in a direction normal to the liquid film and corresponding momentum transfer gradually strengthened and eventually dominated the disruption of liquid into drops,which induced that the initial thickness of the liquid film and the swirl of atomizing air stream exercised a minor influence on the drop sizes.

Effects of Gas Flow Field on Clogging Phenomenon in Close-Coupled Vortical Loop Slit Gas Atomization

In order to study the basic characteristics of gas flow field in the atomizing chamber near the nozzle outlet of the vortical loop slit atomizer and its influence mechanism on clogging phenomenon,the computational fluid dynamics(CFD)software Fluent is used to conduct a numerical simulation of the gas flow field in the atomizing chamber near the nozzle outlet of this atomizer under different annular slit widths,different atomization gas pressures and different protrusion lengths of the melt delivery tube. The results show that under atomization gas pressure p=4.5 MPa,the greater the annular slit width D,the lower the static temperature near the central hole outlet at the front end of the melt delivery tube,and the smaller the aspirating pressure at the front end of the melt delivery tube. These features can effectively prevent the occurrence of the clogging phenomenon of metallic melt. Under an annular slit width of D=1.2 mm,when the atomization gas pressure satisfies 1 MPa ≤ p ≤ 2 MPa and increases gradually,the aspirating pressure at the front end of the melt delivery tube will decline rapidly. This can prevent the clogging phenomenon of metallic melt. However,when the atomization gas pressure p >2 MPa,the greater the atomization gas pressure,the lower the static temperature near the central hole outlet at the front end of the melt delivery tube,and the greater the aspirating pressure at the front end of the melt delivery tube. Hence,the effect of preventing the solidification-induced clogging phenomenon of metallic melt is restricted. When atomization gas pressure is p =4.5 MPa and annular slit width is D=1.2 mm,the greater the protrusion length H of the melt delivery tube,and the smaller the aspirating pressure at its front end. The static temperature near the central hole that can be observed in its front end is approximate to effectively prevent the occurrence of clogging phenomenon of metallic melt. However,because of the small aspirating pressure,the metallic melt flows into the atomizing chamber from the central hole at the front end of the melt delivery tube at an increasing speed and the gas-melt ratio in the mass flow rate is reduced,which is not conducive to the improvement of atomization performance.

Applications of ionic liquids in electrodeposition of rare earths

The electrodeposition and electrochemical behaviors of rare earths in different ionic liquids are summarized. It is demonstrated that most of the rare earths can be electrodeposited in ionic liquids except cerium. Anion of ionic liquids appears to play a significant role in determining the electrochemical windows, and then deciding whether the corresponding ionic liquids can be used for rare earths electrodeposition. The electrochemical behaviors of the reduction process in ionic liquids are similar to those in high-temperature molten salts. The reduction of RE(III) to RE(II) has different reversibility, but the reaction of rare earths to their zerovalent state is irreversible.

Study on Commercial Application of FP-DSN Sulfur Transfer Additive in FCC Unit

The FCC unit with addition of various inventories of the FP-DSN type sulfur transfer additive was tested in a commercial scale. The effect of the sulfur transfer additive was analyzed by investigating the indicators related with the regenerator flue gas composition,the dry gas composition before desulfurization,the LPG composition before desulfurization,the acid gas,and the yield of gasoline and diesel. The test results indicated that the sulfur was trans ferred from the feed stream into the dry gas,LPG and acid gas,and the sulfur transfer effect was obvious only when the inventory of sulfur transfer additive exceeded over 2.0% of total FCC catalyst inventory.

Simulation of liquid-gas flow in full-scale Caroussel oxidation ditch with surface aeration

A model for liquid-gas flow （MLGF）, considering the flee movement of liquid surface, was built to simulate the wastewater velocity field and gas distribution in a full-scale Caroussel oxidation ditch with surface aeration. It was calibrated and validated by field measurement data, and the calibrated parameters and sections were selected based on both model analysis and numerical computation. The simulated velocities of MLGF were compared to that of a model for wastewater-sludge flow （MWSF）. The results show that the free liquid surface considered in MLGF improves the simulated velocity results of upper layer and surface. Moreover, distribution of gas volume fraction （GVF） simulated by MLGF was compared to dissolved oxygen （DO） measured in the oxidation ditch. It is shown that DO distribution is affected by many factors besides GVF distribution.

A Transition from Wood Fuel to LPG and Its Impact on Energy Conservation and Health in the Central Himalayas, India

The aim of the study was to evaluate the impacts of the transition from wood fuel to Liquefied Petroleum Gas （LPG） from energy use and health perspectives along an altitudinal gradient （viz., lower altitude; middle altitude; and higher altitude） of the Central Himalayas. Empirical field study and questionnaire based survey was conducted for obtaining the data. A total of 2o households from each altitude were selected for obtaining reliable information on the actual quantity of fuelwood consumed. Of the 2o households, five households each based on the family size i.e., small families （〈4 members）, medium （5-8 members） and large （〉9 members） from all the altitudinal regions were selected. This was followed by an administration of a questionnaire on the quantity of fuelwood consumed. After the completion of the questionnaire survey, the data was validated using a weighted survey for the randomly selected households for obtaining precise information on the actual quantity of fuelwood consumed. Energy analysis is done with respect to the time spent on fuelwood collection and energy value of burning of per kg of fuelwood. Study indicates that declining biomass requirement from forests contributes significantly towards energy conservation, also has positive impact on human health. Per capita annual energy expenditure on collection of fuelwood is 752 MJ which is higher than any other activity in villages of Central Himalaya. The LPG substitution has contributed to energy saving which is equivalent to 2976-3,742 MJ per capita per year in middle and lower altitudes respectively. In the higher altitude the energy saving is calculated to be about 257 MJ per capita per year. Replacing fuelwood with LPG has made positive impact on society in terms of improving the health while reducing diseases that are caused due to indoor air pollution.

Numerical simulation of spray performance based on the Euler-Lagrange Approach

Numerical simulations have been carried out to investigate the liquid atomization and spray process using the Discrete Phase Model of the commercial CFD code combined with the Wall-Film boundary conditions. The effects of spray parameters on droplets Santer mean diameter （SMD）, droplet collision speed, the thickness of liquid-film, the surface temperature and its uniformity were analyzed in the present study. The simulation results and the experimental data obtained in the available literature agree within 13.8%, The computational results show that the spray pressure is the main factor to realize the atomization. Increasing the mass flux and the spray pressure, the droplet collision speed increases while the corresponding maximum film thickness on the heated surface declines. The surface temperature changes indistinctively with the increase of the spray distance, but the temperature distribution tends to be uniform.

2D materials via liquid exfoliation:a review on fabrication and applications

Since graphene was discovered, the study of two-dimensional(2D) materials with atomic thickness has become a hot spot. To prepare different 2D materials,different methods have been groped, such as mechanical exfoliation, chemical vapor deposition(CVD), liquid-phase exfoliation. This review mainly introduced the sonication liquid-phase exfoliation, an effective method to prepare 2D materials. Compared with mechanical exfoliation and CVD methods, liquid-phase exfoliation is convenient and costeffective and provides high yield. We focused on both theoretical and experimental details of this method. This method was reviewed according to the development of 2D materials from graphene, h-BN to transition metal chalcogenides(TMDs) and black phosphorus nanosheets.We discussed the applications of liquid-exfoliated 2D materials including micro- and nanoelectrical devices,photoelectric devices, and energy storage devices.

LNG储存容器非稳态泄漏模型研究

将LNG蒸发过程考虑在内,结合实际泄漏过程中容器内各参数的动态变化,建立能够准确表征容器非稳态泄漏过程的模型,结合实例进行分析。结果表明,该模型可模拟不同压力容器或常压容器的泄漏过程,并通过分析简化,得到泄漏率的两种简化计算方法。

Cavitation Rates in Water with Dissolved Gas and Other Impurities

Our objective is a better understanding of the role of physical properties of real fluids in the thermodynamics of cavitation in impure water. An extension to the classical homogenous nucleation theory suitable for mixtures is presented in attempt to address the discrepancy between the theoretical predictions and practical observations of cavitation rates in water at normal temperatures. The extension takes into account the non-equilibrium (dissipative) effects involved in nuclei formation through a substance dependent correction coefficient to be determined experimentally. The theory of thermodynamic fluctuations is applied to derive the work of formation of a bubble nucleus. The value of the correction coefficient is estimated using preliminary experimental data from a convergent-divergent nozzle. An application of the results to the numerical prediction of the cavitation zones in a radial-flow water pump is shown.