稀土电热膜在列车集便器中的应用研究

针对目前列车真空集便器在冬季使用时加热保温形式的不足,对稀土电热膜的性能特点和制备工艺进行了技术研究,提出将稀土电热膜技术应用在列车真空集便器上,给出了稀土电热膜在真空集便器上应用的测试装置,并对此进行了实验研究,对实际测量的数据进行了实验对比.结果表明：采用稀土电热膜对列车真空集便器加热保温,不仅可以取代传统的加热形式,而且还有高效、安全、低耗、环保的效果,使得列车真空集便器在冬季也可正常使用.     

Hydrometallurgical separation of rare earth elements, cobalt and nickel from spent nickel-metal-hydride batteries

The separation of rare earth elements, cobalt and nickel from NiMH battery residues is evaluated in this paper. Analysis of the internal content of the NiMH batteries shows that nickel is the main metal present in the residue (around 50% in weight), as well as potassium (2.2-10.9%), cobalt (5.1-5.5%), rare earth elements (15.3-29.0%) and cadmium (2.8%). The presence of cadmium reveals that some Ni-Cd batteries are possibly labeled as NiMH ones. The leaching of nickel and cobalt from the NiMH battery powder with sulfuric acid is efficient; operating variables temperature and concentration of H₂O₂ has no significant effect for the conditions studied. A mixture of rare earth elements is separated by precipitation with NaOH. Finally, solvent extraction with D2EHPA (di-2-ethylhexyl phosphoric acid) followed by Cyanex 272 (bis-2,4,4-trimethylpentyl phosphinic acid) can separate cadmium, cobalt and nickel from the leach liquor. The effect of the main operating variables of both leaching and solvent extraction steps are discussed aiming to maximize metal separation for recycling purposes.     

IC反应器处理低浓度有机废水的启动实验研究

对内循环厌氧反应器(IC反应器)在(33±O.5)℃下处理低浓度有机废水的启动特性进行了实验研究.结果表明:反应器经过59 d启动成功:当进水COD浓度为411.6 mg/L,HRT为0.8 h.相应的有机负荷COD为12.3 kg/(m3·d)时,其COD去除率能稳定在87%左右,日产气率15 m3/(m3·d)左右,出水VFA浓度HAc为41.2～43.6 mg/L;污泥床反应区COD去除量占总COD去除量的77%以上,远大于精细处理区;启动完成后,反应器底部形成了颗粒污泥,镜检发现颗粒污泥表面分布着丝状菌,内部则以杆菌和球菌为主.     

Effect of wastewater treatment processes on the pyrolysis properties of the pyrolysis tars from sewage sludges

The pyrolysis properties of five different pyrolysis tars, which the tars from 1# to 5# are obtained by pyrolyzing the sewage sludges of anaerobic digestion and indigestion from the A2/O wastewater treatment process, those from the activated sludge process and the indigested sludge from the continuous SBR process respectively, were studied by thermal gravimetric analysis at a heating rate of 10 ℃/min in the nitrogen atmosphere. The results show that the pyrolysis processes of the pyrolysis tars of 1#, 2#, 3# and 5# all can be divided into four stages: the stages of light organic compounds releasing, heavy polar organic compounds decomposition, heavy organic compounds decomposition and the residual organic compounds decomposition. However, the process of 4# pyrolysis tar is only divided into three stages: the stages of light organic compounds releasing, decomposition of heavy polar organic compounds and the residual heavy organic compounds respectively. Both the sludge anaerobic digestion and the "anaerobic" process in wastewater treatment processes make the content of light organic compounds in tars decrease, but make that of heavy organic compounds with complex structure increase. Besides, both make the pyrolysis properties of the tars become worse. The pyrolysis reaction mechanisms of the five pyrolysis tars have been studied with Coats-Redfern equation. It shows that there are the same mechanism functions in the first stage for the five tars and in the second and third stage for the tars of 1#, 2#, 3# and 5#, which is different with the function in the second stage for 4# tar. The five tars are easy to volatile.     

The role of foreign cations in enhancing the oxygen solubility properties of alkali molten carbonate systems: Brief survey of existing data and new research results

This work presents a summary of experimental data on the oxygen solubility-speciation properties of alkali molten carbonates that have been obtained by the authors through the development of a highly sensitive analysis method. The purpose of this summary is to show in particular the effect of foreign cation additions on both oxygen solubility and dissolution mechanisms at 650 °C. Our findings may be used to clearly indicate that rare earth and magnesium cations are the most effective in enabling oxygen solubility and basicity/oxidizing melt properties. The second part of this work reports new experimental results concerning the effect of simultaneous additions of La and Mg cations to an eutectic Li/Na carbonate system. A dramatic increase in oxygen solubility and active peroxide oxygen species has been found, thus revealing a strong synergistic effect of rare earth and alkaline earth cations on the molten carbonate oxygen chemistry. The results of this investigation suggest therefore that foreign cation addition is a potentially attractive option to design alkali molten carbonate salts with a high oxidizing power.     

An experimental study on the bulk precipitation mechanism of physical water treatment for the mitigation of mineral fouling

The present study investigated the mechanism of physical water treatment (PWT) using particle count analyses of water. The PWT method utilized in the present study included catalytic devices and low-voltage–high-frequency device through which water continuously recirculated. Concentrated hard water at electrical conductivity of 2300–2700 μS/cm was circulated in the study at two different flow rates (i.e., 500 l/h and 800 l/h) at the room temperature. After 66 h of operation for each test, the total number of particles in water for the PWT cases increased by 165–540% as compared with those for the no-treatment cases, depending on the flow rate used. The present particle counting results provided a support for the bulk precipitation hypothesis as the mechanism of PWT, which is essentially an electro-flocculation process.     

High performance rare earth oxides LnOx (Ln = La, Ce, Nd, Sm and Dy)-modified Pt/SiO2 catalysts for CO oxidation in the presence of H2

The catalytic activities of low-temperature CO oxidation and preferential CO oxidation (PROX) in rich-H₂ stream over the Pt/SiO₂ and rare earth oxides modified Pt/SiO₂ catalysts have been investigated. The addition of rare earth oxide additives to the Pt/SiO₂ catalyst can promote the catalytic performance remarkably. The catalytic activities for PROX are dependent on the basicities of these oxides. The higher basic strength leads to higher activity. For Pt–CeO₂/SiO₂, the catalytic activity depends strongly on the content of CeO₂ and on the mole ratio of CO/O₂. XRD and H₂-temperature-programmed reduction (TPR) results show that the additives not only improve the dispersion of metallic Pt on the support surface, but also increase the reducibility of PtOx in Pt–CeO₂/SiO₂. The formation of the Pt–Ce alloy decreases the electron back-donation from the Pt 5d orbital to the 2σ* orbital of CO, and consequently suppresses CO–Pt bonding, resulting in the lowered CO coverage.     

A highly active Ni-Al2O3 catalyst prepared by homogeneous precipitation using urea for internal reforming in a molten carbonate fuel cell (MCFC): Effect of the synthesis temperature

Ni-Al₂O₃ catalysts for use in internal reforming in a molten carbonate fuel cell (MCFC) were prepared by homogeneous precipitation method at various synthesis temperatures. The effects of synthesis temperature on physicochemical properties and catalytic activities of the Ni-Al₂O₃ catalysts were investigated. XRD measurements exhibited that the peak intensity of NiAl₂O₄ in the calcined catalysts increased with higher synthesis temperatures. TPR measurements demonstrated that reduction peaks appeared around 670–680 °C for every synthesis temperature, indicating that the Ni particles interacted strongly with the support. Hydrogen chemisorption results showed that nickel dispersion and nickel surface area decreased in the order: K52_80C > K52_85C > K52_90C > K52_95C > K52_100C. TEM images of the reduced Ni-Al₂O₃ catalysts revealed that the average sizes of Ni particles were 13.1, 13.4 and 15.9 nm for K52_80C, K52_90C and K52_100C, respectively, which means that a higher synthesis temperature yielded a larger Ni particle. The performance of the catalysts in methane steam reforming showed that catalysts prepared at the lowest synthesis temperature (80 °C) exhibited the highest reaction rate. These results suggest that a lower synthesis temperature is favorable to prepare highly active Ni-Al₂O₃ catalysts by the homogeneous precipitation method.     

脱硫废水深度降氟机理及工艺优化的试验研究

在静态试验装置中,通过化学沉淀与混凝法相结合的二次除氟工艺处理电厂高浓度含氟脱硫废水,采用正交试验研究了多因素操作条件对脱硫废水除氟效率的综合影响．结果表明：氯化钙除氟性能优于氢氧化钙,最佳钙氟摩尔比n（Ca）／n（F）一l：1.3;添加硫酸铝、氯化铁等混凝剂可明显改善药剂的除氟性能,确定了最佳”（A1）／n（F）=1．5、最佳n（Fe）／n（F）=0．3;在PH=5～6的弱酸性条件、温度约为30℃、转速约为500r／min、添加聚丙烯酰胺（PAM）质量分数约为0．1％的情况下,除氟效率高达95％以上;影响脱硫废水除氟效率的因素由主到次依次为：CaCl2〉Al2（SO4）3〉PAM〉FeCl3〉PH〉温度〉搅拌转速．     

Comparative study on the production of biohydrogen from rice mill wastewater

This study presents the production of biohydrogen from rice mill wastewater. The acid hydrolysis and enzymatic hydrolysis operating conditions were optimized, for better reducing sugar production. The effect of pH and fermentation time on biohydrogen production from acid and enzymatic hydrolyzed rice mill wastewater was investigated, using Enterobacter aerogenes and Citrobacter ferundii. The enzymatic hydrolysis produced the maximum reducing sugar (15.8 g/L) compared to acid hydrolysis (14.2 g/L). The growth data obtained for E. aerogenes and C. ferundii, fitted well with the Logistic equation. The hydrogen yields of 1.74 mol H₂/mol reducing sugar, and 1.40 mol H₂/mol reducing sugar, were obtained from the hydrolyzate obtained from enzymatic and acid hydrolysis, respectively. The maximum hydrogen yield was obtained from E. aerogenes compared to C. ferundii, and the optimum pH for better hydrogen production was found to be in the range from 6.5 to 7.0. The chemical oxygen demand (COD) reduction obtained was around 71.8% after 60 h of fermentation.     

厌氧技术处理生活污水及其效果分析

厌氧生活污水分散处理技术具有投资少、能耗低、运行费用小和处理效率高等优点,已成为分散处理城镇生活污水的主要技术,应用前景十分广阔;文章分析和讨论了该技术的原理、设计、工艺和运行效果,结果表明,出水能够达到国家二级排放标准。     

Simultaneous biohydrogen production and wastewater treatment based on the selective enrichment of the fermentation ecosystem

Biohydrogen production from synthetic wastewater as substrate was studied in anaerobic small scale batch reactors. Enriched anaerobic mixed consortia sampled from various environments were used as parent inocula to start the bioreactors. Selective enrichments were achieved by various physical and chemical pretreatments and changes in the microbial communities were monitored by metagenomic and molecular diagnostics approaches. Experimental data showed the feasibility of biohydrogen production using synthetic wastewater as substrate. The hydrogen generation capability of the different mixed consortia is clearly dependent on the pretreatment methods. The described approach opens the possibility for an alternative way towards simultaneous wastewater treatment and renewable energy generation.     

微藻生物膜去污技术应用研究进展

文章综述了微藻生物膜净化污水和生产生物燃料等方面的国内外最新成果,阐述了典型微藻去污生物膜系统的运行情况、综合效益、优缺点和推广价值,并对微藻生物膜去污技术存在的问题及关键技术进展及发展趋势进行了分析,就微藻生物膜去污技术的规模化及产业化应用提出了建议,以期为微藻生物膜去污技术的成熟和规模应用提供理论和实践支撑。     

Effect of heat treatment and chemical composition on the corrosion behavior of FeAl intermetallics in molten (Li + K)carbonate

The corrosion performance of various Fe–Al alloys in 62 mol. %Li₂CO₃-38 mol.%K₂CO₃ at 650 °C has been studied using the weight loss technique. Alloys included FeAl with additions of 1, 3 and 5 at.% of either Ni or Li with or without a heat treatment at 400 °C during 144 h. For comparison, 316L type stainless steel was also studied. The tests were complemented by X-ray diffraction (XRD), scanning electronic microscopy and microchemical studies. Results showed that FeAl base alloy without heat treatment had the highest corrosion rate but by either heat treating it or by adding either Ni or Li the mass gain was decreased. When the FeAl base alloy was heat treated and alloyed with either 5Ni or 1Li the degradation rate reached as low values as those found for 316L stainless steel which had the lowest degradation rate. Both Ni and Li improved the adhesion of external protective layer either by avoiding the formation of voids or by lowering the number of precipitates and making them more homogenously distributed.     

催化装置分馏塔顶部结盐的原因分析及对策

介绍了大连石化公司三催化装置分馏塔结盐情况,对结盐现象进行了分析,通过采取在线水洗措施解决了塔顶结盐问题,取得了好的效果。     

Partitioning of rare earths and some major elements in the Kizildere geothermal field, Turkey

Rare earth elements and yttrium (REY), Na⁺, K⁺, Cl⁻, and Ca²⁺ were determined in water, steam, mineral scale and rock samples from the Kizildere geothermal field, Turkey. The CO₂-rich parent fluid originates from a sequence of mica schists with marble intercalations. The chemistry of the parent fluid varies with location and time. The average REY composition of the fluids is derived by extrapolation to the lowest Ca concentrations. The apparent vapor–liquid partitioning factors for REY at 145 °C and 5 bar total absolute pressure are about 0.2, whereas for Ca²⁺, Na⁺, K⁺ and Cl⁻ they are <0.05, about 0.0005, 0.0005 and about 0.02, respectively. Apparent scale-liquid distribution coefficients for REY at 145 and 190 °C are about 0.15 and 0.55, whereas at 100 °C they increase from 0.3 (La) to 1.5 (Lu).     

Experimental study of effect of anolyte concentration and electrical potential on electrolyzer performance in thermochemical hydrogen production using the Cu-Cl cycle

An important process in the copper-chlorine water splitting cycle for hydrogen production is electrolysis which occurs after a series of cycle steps that produce the constituents for the anolyte of the electrochemical cell. In this investigation, an anolyte mixture of HCl/CuCl/H₂O of varying concentrations is circulated through the electrolyzer to assist in optimizing its performance. It is observed that the concentration and temperature of the anolyte directly affect the process. The efficiency of the electrolyzer is adversely affected, after running a series of experiments, due to copper deposition on the membrane. An important implication of the results is that, to determine the optimal electrolyzer performance, one needs to vary the flow rate and the concentration of anolyte, for a given constant voltage source. In addition, this work demonstrates that aqueous CuCl₂ can be recovered from the waste solution exiting the electrolyzer and recycled to the hydrolysis reactor.     

Vapour/liquid fractionation of rare earths,Y, Na,K, NH4, Cl,HCO3, SO4 and borate in fluids from the Piancastagnaio geothermal field,Italy

Vapour/liquid fractionation of rare earth elements and yttrium (REY), Na⁺, K⁺, NH₄⁺, HCO₃⁻, SO₄²⁻, Cl⁻ and borate in geothermal fluids from the Piancastagnaio geothermal field (Mt. Amiata geothermal area, Tuscany, central Italy) were evaluated based on the chemistry of collected liquids and condensed vapours. Apparent vapour–liquid partitioning factors (^appD^V/L) of REY vary from 0.3 to 0.01. These factors are much higher than those of Na (<0.001) and K (∼0.001). Volatile components are ion pairings such as NH₄HCO₃^o, NH₄Cl^o, NaHCO₃^o, CaSO₄^o and REYO(HCO)₃^o ⇔ REY(OH)CO₃^o. In vapour, REY and NH₄⁺ are negatively correlated. High and low ^appD^V/L(REY) indicate variations of NH₄⁺ concentrations in liquids. The results of this study are relevant to the understanding of element migration and deposition under hydrothermal boiling conditions.     

Experimental study on heat and fluid flow in LNG tank heated from the bottom and the sidewalls

Heat and fluid flow in a layer heated from the bottom and the sidewalls simulating an underground LNG tank is experimentally studied under high Rayleigh number (7.5×10¹⁰<Ra<1.5×10¹³) conditions by electrochemical mass transfer technique. The experiment yielded the following results. When sidewalls are heated, the heat transfer along the bottom surface is reduced. Heat transfer along sidewalls is independent of bottom heating, and is modeled by an equation for laminar natural convection flow even for Ra>10⁹. Convective flow pattern in the tank is visualized by the Schlieren technique. The results, combined with local mass transfer measurement, show that Sh of the bottom surface is reduced in the area where impinging downward flow exists. It is caused by the suppression of thermal plume formation by the downward flow. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(7): 417–430, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20031     

Impact of the modification method of Ni/ZrO2 catalyst by alkali and alkaline earth metals on its activity in thermo-chemical conversion of cellulose

The goal of this work is to determine an impact of the modification method of Ni/ZrO₂ catalyst by alkali and alkaline earth metals on its activity in thermo-chemical conversion of cellulose to hydrogen-rich gas. Me_xO-ZrO₂ supports (where Me = Ca, Mg, Na or K) were prepared by impregnation, precipitation and sol-gel methods. The obtained results reveal that an introduction of dopants to the zirconia support considerably enhances the H₂ yield in comparison to unmodified catalyst. An increase in the hydrogen formation is accompanied by a rise in the total volume of the produced gases. It is demonstrated that the highest amount of hydrogen is formed in the presence of the catalysts containing CaO-ZrO₂ support followed by Na doped materials. This phenomenon can be attributed to more efficient incorporation of Ca²⁺ and Na⁺ cations in the zirconia lattice making it more stable in the reaction conditions. Moreover, it is observed that an activity order of the investigated catalysts is consistent with the changes in the basic character of their surface.