曝气-Fenton处理焚烧厂渗滤液MBR-NF浓缩液研究

采用曝气-Fenton法对焚烧厂渗滤液经MBR-NF处理后产生的浓缩液进行预处理.探讨FeSO4·7H2O投加量、H2O2投加量、pH等因素对COD去除率及UV254、E4/E6的影响,并在此基础上对该反应降解COD过程的动力学方程进行分析与讨论.结果表明,最佳反应条件为:初始pH值为3,FeSO4· 7H2O投加量为0.025mol/L,H2O2投加量为0.125mol/L.曝气-Fenton法对焚烧厂渗滤液膜浓缩液的COD降解过程符合二级反应动力学方程.     

印染废水膜后浓水的深度处理工艺研究

采用Fenton法+反硝化生物滤(DN)池的深度处理工艺处理印染废水膜后(RO)浓水,考察了H2O2加药量、FeSO4.7H2O加药量、初始pH值和反应时间对Fenton法去除COD的影响,以及C/N、水力停留时间(HRT)对DN池去除NO3--N的影响.研究结果表明:在初始pH值为4,FeSO4·7H2O和H2O2的投加量分别为450mg/L、90mg/L,反应时间为1.5h时,COD去除率达到62％,出水COD71mg/L,色度15倍;DN池在C/N为8,HRT为2h时,出水NO3--N降低至0.52mg/L,NO3--N去除率达到96.8％.RO浓水经上述工艺处理后出水水质稳定达到《纺织染整工业水污染物排放标准》(GB4287-2012)表2限值.     

催化氧化法处理电厂离子交换树脂再生废水

介绍了采用催化氧化法（Fenton试剂）对电厂离子交换树脂再生废水进行催化氧化处理的实验研究,结果表明,当溶液pH值为2.0、H2O2（30%）投加量为60 mL/L、FeSO4·7H2O投加量为4.5 g/L、H2O2投加次数为4、反应时间为1.5 h时,废水的处理效果最佳。     

铁碳微电解-Fenton试剂法处理高浓度表面活性剂废水研究

废水中的表面活性剂使水面产生大量不易消失的泡沫,并对动植物和人体有害。采用铁碳微电解-Fenton试剂法,以某公司不同时间段的废水为实验水样,进行了高浓度表面活性剂废水的处理效果实验研究。实验考察了不同Fe/C值、进水pH值、m（FeSO4）/v（H2O2）值以及水力停留时间、气水化、氧化剂量等工艺参数对高浓度表面活性剂废水的处理效果。结果表明,采用该工艺。在进水LAS浓度为1950～3020mg/L时,微电解反应器进水pH值为3～4、铁碳质量比（Fe/C）为2：1、水力停留时间（HRT）为60min、气水比（体积比）为12：1;催化氧化反应器进水pH值小于5、m（FeSO4）/v（H2O2）比值为1/10、H2O2加入量为5mL/L、反应时间为4h的条件下,联合处理后表面活性剂平均去除率大于90%.     

芬顿氧化法处理含金刚烷胺废水

采用Fenton试剂氧化法处理含金刚烷胺废水,研究在不同反应条件下Fenton试剂对金刚烷胺废水COD的去除效果,确定反应的最佳条件.研究结果表明:pH值为3～4,反应温度为常温(23～25℃),H2O2:投加量为450mEL,H2O2与Fe2+的质量比为3左右,处理浓度为600mg/L的含金刚烷胺废水COD的去除率为30%以上,处理效果良好.因此,使用Fenton试剂氧化金刚烷胺废水的方法是可行的.     

统计学实验设计分析颗粒状TiO2光催化AB7染料废水

利用颗粒状纳米TiO2在间歇光反应器中对酸性湖蓝光催化氧化脱色进行了研究,并根据统计学的响应面方法对光催化氧化酸性湖蓝的主要因素(初始pH值、光强、TiO2浓度)进行了探讨和分析.为了得到这3个因素之间的相互关系并优化这些参数,实验采用Box-Behnken设计方法,其中初始pH值、光强、TiO2浓度的高、低水平分别为3.3～5.7,11.11～20.11×102 μW/cm2,0.4～1.4mg/L,分析参数为脱色率的变化.通过使用Design-Expert 5软件可得到1个2次响应曲面模型,并得到最佳的初始pH值、光强、TiO2浓度分别为3.46、16.50×102 μW/cm2、0.98mg/L,从而脱色率也达到最大(98.82%).     

核桃内生细菌Bacillus subtilis HB1310发酵棉秆水解糖液产油工艺优化

为实现核桃内生产油细菌Bacillus subtilis HB1310发酵棉秆水解糖液高效生产微生物油脂,检测了糖液浓度、氮源浓度、发酵起始p H值以及发酵时间4个主要因素对该菌株发酵棉秆水解糖液产油率的影响。通过单因素试验确定了响应面试验中各因素的水平中心点。通过响应面试验确定了菌株发酵棉秆水解糖液产油的优化工艺参数为糖液浓度7%(w/v)、氮源浓度5 g/L、发酵起始p H值6.0、发酵时间2 d,在此优化工艺条件下进行验证试验,获得的产油率可达30.26%±1.05%(w/w),与模型的理论预测值较接近,说明建立的模型是切实可行的。     

玉米秸秆水解液燃料乙醇发酵条件优化

以实验室前期构建的工业酿酒酵母HN-1-24为出发菌株,研究利用玉米秸秆水解液发酵生产燃料乙醇的培养条件。在单因素实验的基础上,通过Plackett-Burman设计,进行主要影响因子筛选;利用Box-Behnken设计和响应面优化分析,得到主要影响因子的最优组合。结果表明,影响乙醇产量的显著因子是蛋白胨浓度、MgSO_4·7H_2O浓度和初始pH值;三因子最优组合为蛋白胨浓度1.0 g/L、MgSO_4·7H_2O浓度0.6 g/L和初始pH值5.5,确定最适发酵条件。在此条件下,乙醇产量为43 g/L,与模型预测值一致;乙醇产率达到理论值的83%,比优化前提高5%。     

光／电Fenton催化降解有毒有机污染物

在可见光(λ>450nm)照射并通外加电压(E=3V)条件下,以染料酸性桃红(Sulforhodamine B,SRB)及有机无色小分子化合物2,4-二氯苯酚(2,4-dichlomphenol,DCP)为目标物,探索光电Fenton降解其最佳反应条件,结果表明,对1.0×10-5mol/L SRB Fenton试剂(Fe3+/H2O2)在pH=3.0,H2O2浓度为7.49×10-4mol/L,Fe3+为2.48×10-4mol/L时,SRB降解效果最好.通过分析SRB及DCP降解过程紫外.可见光谱(UV-Vis)、红外光谱(FTIR)和总有机碳(TOC)测定,发现光电Fenton体系能使SRB和DCP发生有效的降解,SRB反应300min矿化率达到96.38%,DCP反应90min降解率达到100%.采用酶分析法和苯甲酸荧光分析法分别测定了在光电催化降解有机污染物过程中H2O2和羟基自由基(·OH)的变化,表明此光催化降解过程涉及·OH历程.     

大叶黄杨废弃物光合生物制氢工艺参数优化研究

以产氢量为主要考察指标,通过响应面Box-Behnken模型优化大叶黄杨废弃物光合生物制氢的工艺参数,对其主要影响因素之间的关系进行研究。结果表明：温度对大叶黄杨废弃物光合生物制氢工艺的影响最大;光照强度与初始pH值、温度等的交互作用均对产氢量的影响比较显著;最佳产氢工艺条件为温度28.78℃、初始pH值7.00、光照强度3 067.0 lx,此时拟合产氢量为71.81 mL/g,实际产氢量为70.15 mL/g;拟合值和实际值的相对误差为2.31%,表明该数值模型具有较好的拟合性。     

Performance assessment of some ice TES systems

In this paper, a performance assessment of four main types of ice storage techniques for space cooling purposes, namely ice slurry systems, ice-on-coil systems (both internal and external melt), and encapsulated ice systems is conducted. A detailed analysis, coupled with a case study based on the literature data, follows. The ice making techniques are compared on the basis of energy and exergy performance criteria including charging, discharging and storage efficiencies, which make up the ice storage and retrieval process. Losses due to heat leakage and irreversibilities from entropy generation are included. A vapor-compression refrigeration cycle with R134a as the working fluid provides the cooling load, while the analysis is performed in both a full storage and partial storage process, with comparisons between these two. In the case of full storage, the energy efficiencies associated with the charging and discharging processes are well over 98% in all cases, while the exergy efficiencies ranged from 46% to 76% for the charging cycle and 18% to 24% for the discharging cycle. For the partial storage systems, all energy and exergy efficiencies were slightly less than that for full storage, due to the increasing effect wall heat leakage has on the decreased storage volume and load. The results show that energy analyses alone do not provide much useful insight into system behavior, since the vast majority of losses in all processes are a result of entropy generation which results from system irreversibilities.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Effect of co-cultivation of Chlamydomonas reinhardtii with Azotobacter chroococcum on hydrogen production

Chlamydomonas reinhardtii cc124 and Azotobacter chroococcum bacteria were co-cultured with a series of volume ratios and under a variety of light densities to determine the optimal culture conditions and to investigate the mechanism by which co-cultivation improves H₂ yield. The results demonstrated that the optimal culture conditions for the highest H₂ production of the combined system were a 1:40 vol ratio of bacterial cultures to algal cultures under 200 μE m^?2 s^?1. Under these conditions, the maximal H₂ yield was 255 μmol mg^?1 Chl, which was approximately 15.9-fold of the control. The reasons for the improvement in H₂ yield included decreased O₂ content, enhanced algal growth, and increased H₂ase activity and starch content of the combined system.     

Natural-gas fueled spark-ignition (SI) and compression-ignition (CI) engine performance and emissions

Natural gas is a fossil fuel that has been used and investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines. Compared with conventional gasoline engines, SI engines using natural gas can run at higher compression ratios, thus producing higher thermal efficiencies but also increased nitrogen oxide (NO_x) emissions, while producing lower emissions of carbon dioxide (CO₂), unburned hydrocarbons (HC) and carbon monoxide (CO). These engines also produce relatively less power than gasoline-fueled engines because of the convergence of one or more of three factors: a reduction in volumetric efficiency due to natural-gas injection in the intake manifold; the lower stoichiometric fuel/air ratio of natural gas compared to gasoline; and the lower equivalence ratio at which these engines may be run in order to reduce NO_x emissions. High NO_x emissions, especially at high loads, reduce with exhaust gas recirculation (EGR). However, EGR rates above a maximum value result in misfire and erratic engine operation. Hydrogen gas addition increases this EGR threshold significantly. In addition, hydrogen increases the flame speed of the natural gas-hydrogen mixture. Power levels can be increased with supercharging or turbocharging and intercooling. Natural gas is used to power CI engines via the dual-fuel mode, where a high-cetane fuel is injected along with the natural gas in order to provide a source of ignition for the charge. Thermal efficiency levels compared with normal diesel-fueled CI-engine operation are generally maintained with dual-fuel operation, and smoke levels are reduced significantly. At the same time, lower NO_x and CO₂ emissions, as well as higher HC and CO emissions compared with normal CI-engine operation at low and intermediate loads are recorded. These trends are caused by the low charge temperature and increased ignition delay, resulting in low combustion temperatures. Another factor is insufficient penetration and distribution of the pilot fuel in the charge, resulting in a lack of ignition centers. EGR admission at low and intermediate loads increases combustion temperatures, lowering unburned HC and CO emissions. Larger pilot fuel quantities at these load levels and hydrogen gas addition can also help increase combustion efficiency. Power output is lower at certain conditions than diesel-fueled engines, for reasons similar to those affecting power output of SI engines. In both cases the power output can be maintained with direct injection. Overall, natural gas can be used in both engine types; however further refinement and optimization of engines and fuel-injection systems is needed.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Exergetic evaluation of 5 biowastes-to-biofuels routes via gasification

This paper presents the exergy analysis results for the production of several biofuels, i.e., SNG (synthetic natural gas), methanol, Fischer–Tropsch fuels, hydrogen, as well as heat and electricity, from several biowastes generated in the Dutch province of Friesland, selected as one of the typical European regions. Biowastes have been classified in 5 virtual streams according to their ultimate and proximate analysis. All production chains have been modeled in Aspen Plus in order to analyze their technical performance. The common steps for all the production chains are: pre-treatment, gasification, gas cleaning, water–gas-shift reactions, catalytic reactors, final gas separation and upgrading. Optionally a gas turbine and steam turbines are used to produce heat and electricity from unconverted gas and heat removal, respectively. The results show that, in terms of mass conversion, methanol production seems to be the most efficient process for all the biowastes. SNG synthesis is preferred when exergetic efficiency is the objective parameter, but hydrogen process is more efficient when the performance is analyzed by means of the 1st Law of Thermodynamics. The main exergy losses account for the gasification section, except in the electricity and heat production chain, where the combined cycle is less efficient.     

Decomposition of limestone in a solar reactor

The thermal decomposition of limestone has been selected as a model reaction for developing and testing an atmospheric open solar reactor. The reactor consists of a cyclone gas/particle separator which has been modified to let the concentrated solar energy enter through a windowless aperture. The reacting particles are directly exposed to the solar irradiation. Experimentation with a 60 kW reactor prototype was conducted at PSI's 90m² parabolic solar concentrator, in a continuous mode of operation. A counter-current flow heat exchanger was employed to preheat the reactants. Eighty five percent degree of calcination was obtained for cement raw material and 15% of the solar input was converted into chemical energy (enthalpy).The technical feasibility of the solar thermal decomposition of limestone was experimentally demonstrated. The use of solar energy as a source for high-temperature process heat offers the potential of reducing significantly the CO₂ emissions from lime producing plants. Such a solar thermochemical process can find application in sunny rural areas for avoiding deforestation.