基于反渗透技术的氨-水-氢氧化钠三元工质吸收式制冷系统性能模拟

反渗透是一种实现溶液中特定离子分离的成熟方法,将其应用于氨-水-氢氧化钠三元工质吸收式制冷系统中实现氢氧化钠分离,可以解决氢氧化钠在吸收器中产生的不利影响。本文采用Aspen Plus流程模拟软件建立采用反渗透装置的氨-水-氢氧化钠三元工质吸收式制冷系统模型,分析在不同发生温度下氢氧化钠质量分数对系统性能系数(COP)的影响,以及不同氢氧化钠质量分数下系统COP随溶液截留率的变化。结果表明:采用反渗透装置时,在氢氧化钠质量分数为15%时系统COP提升最大,相较于不采用反渗透装置的系统可提高33%,但在氢氧化钠质量分数高于15%时COP下降;反渗透装置在分离氢氧化钠浓溶液时使部分氨水稀溶液无法进入低压侧,减少了吸收器中溶液量,导致循环倍率上升和系统COP下降;溶液截留率增大时,COP会持续下降,最大会降低39%。利用分析法对反渗透装置的能耗进行分析,在氢氧化钠质量分数小于15%时,加压泵功耗占系统消耗的比例小于6%。

石膏脱水机真空泵卡涩原因分析及处理

针对江苏某电厂石膏脱水机真空泵卡涩问题,进行了轴承表面结垢的化学成分分析,得出泵内工质水由工业水变为化学水处理排放的废水后,pH值升高、钙镁硬度变大,引起结垢。采取药剂清洗的措施后,在短时间使真空泵恢复正常运行,同时提出定期检查回用水系统有无异常,在回用水池出水侧、三期工业废水回水出水母管处加装pH表等一系列设备运行的改进建议,有效解决了真空泵结垢卡涩问题。

Kalina循环与Rankine循环在水泥窑低温余热发电中的热力学对比分析

从热力学第一定律出发,采用工质热物性软件NIST获取较高精度的工质热物性,对一级蒸馏Kalina循环在水泥窑低温废气余热发电方面进行了热力学计算分析。分析了汽轮机进口压力变化对Kalina循环热功转换的影响,并从不可逆损失与发电功率两个方面对比分析了Kalina循环与Rankine循环,表明在一定实际工程条件下Kalina循环发电功率并不是始终大于Rankine循环。文中还从传热学、投资、运行维护、环境保护等方面对Kalina循环应用于实际工程遇到的技术经济问题进行了探讨,指出了今后的研究方向。

Electrolyte engineering for optimizing anode/electrolyte interface towards superior aqueous zinc-ion batteries:A review

Aqueous zinc-ion batteries(AZIBs) are promising candidates for the large-scale energy storage systems due to their high intrinsic safety,cost-effectiveness and environmental friendliness.However,issues such as dendrite growth,hydrogen evolution reaction,and interfacial passivation occurring at the anode/electrolyte interface(AEI) have hindered their practical application.Constructing a stable AEI plays a key role in regulating zinc deposition and improving the cycle life of AZIBs.The fundamentals of AEI and the challenges faced by the Zn anode due to unstable interfaces are discussed.A comprehensive summary of electrolyte regulation strategies by electrolyte engineering to achieve a stable Zn anode is provided.The effectiveness evaluation techniques for stable AEI are also analyzed,including the interfacial chemistry and surface morphology evolution of the Zn anode.Finally,suggestions and perspectives for future research are offered about enabling a durable and stable AEI via electrolyte engineering,which may pave the way for developing high-performance AZIBs.

Kalina地热发电热力循环效率影响因素分析

结合Kalina循环系统的工作原理,采用EES软件平台编制计算软件,并完成了系统循环过程的模拟计算,计算结果与实际运行参数吻合较好。在此基础上,对Kalina地热发电循环进行分析,从冷凝水温度、汽轮机入口压力以及氨的质量浓度等方面研究对循环效率的影响。结果表明,系统循环效率随着汽轮机入口压力存在峰值,随基本溶液中氨的质量浓度的升高而升高,但氨的质量浓度过高就要求发生器换热面积过大,造成系统整体经济性下降。此外,还对汽轮机的安全运行进行了分析。

Kalina循环的热力学第一定律分析

从热力学第一定律的角度出发,选取P-R方程作为氨-水混合物性质的基本计算公式,对一级蒸馏Kalina循环进行了热力学分析。编制了氨-水混合工质热力性质及Kalina循环热力性能计算程序,对Kalina循环热功转换的主要热力性能进行了理论计算,分析了透平进口压力、透平进口温度、透平背压、工作溶液浓度、基本溶液浓度、循环倍增率等关键参数对循环性能的影响。

Kalina地热发电循环模型建立及热力性能分析

以Kalina地热发电循环（KCSll）为研究对象，针对冷热源温度、工质浓度比及循环压力等参数的变化对KCS11循环效率的影响进行研究。基于Engineering Equation Solver（EES）工程软件平台，编写KCSl1运行参数的计算模型。模拟结果与文献中的数据进行对比，拟合程度较好。进一步研究表明，系统运行中氨水浓度应略高于最高效率点所对应的浓度值，且系统压力应等于或略大于最高效率所对应的压力值。通过对冷热源温度、浓度、压力等参数分析，热源温度升高或冷源温度降低10℃，系统循环效率可提高2．0％～3．5％。在特定冷热源温度下，当氨水浓度增加0．10，循环最大效率所对应的压力增大0．8MPa，系统泵耗随之增加，故系统效率存在极值点。因此在系统运行中应考虑氨水浓度与系统压力的匹配，保证系统能够高效运行。

太阳能柱式吸热器非均匀受热的数值模拟

塔式太阳能热发电站中的吸热器是光热转换的重要设备,其由多根无间隙排列的集热管组成。通常集热管表面接收的太阳辐射能流极不均匀,当水/蒸汽作为集热管内的传热工质时,管内工质状态为复杂的沸腾两相流动,因此研究其受热特性具有重要价值。本文基于Fluent平台,利用VOF(Volume of Fluid)方法,建立了不均匀能流边界条件下水/蒸汽集热管的数值模型。模拟分析呈现了管内汽液两相的流动特性;得到了集热管管内工质和管壁的温度分布和集热管内壁面的努塞尔数分布。

Integrated assessment of sea water quality based on BP artificial neural network

In order to carry out an integrated assessment of sea water quality objectively, this paper based on the concept and principle of artificial neural network, generated appropriate training samples for BP artificial neural network model through the method of producing samples to the concentration of various pollution index of sea water quality from the viewpoint of threshold, established the BP artificial neural network model of sea water quality assessment using multi-layer neural network with error back-propagation algorithm. This model was used to assess water environment and obtain sea water quality categories of offshore area in Bohai Bay through calculating. The calculations shown that pollution index in river＇s wet season was higher than that in dry season from 2004 to 2007, and the pollution was particularly serious in 2005 and 2006, but a little better in 2007. The assessed results of cases shown that the model was reasonable in design and higher in generalization, meanwhile, it was common, objective and practical to sea water quality assessment.

Rainwater quality assessment of a solidified soil cistern using new construction technology

A plastic mixture construction technology using MBER （material becoming earth into rock） soil stabilizer is introduced and the water quality of a solidified soil cistern using the technology is analyzed. Rainwater was harvested in July, 2012. Water quality of runoff and cistern water after storage was measured, including turbidity, chemical oxygen demand （COD）, total nitrogen, nitrate, and ammonia. Results show that pollutant concentrations in runoff decreased with time, indicating that runoff in the early time should be removed. Nitrate concentrations in cistern water increased after storage, while the remaining parameters decreased. Measured pollutant concentrations did not exceed the limit according to the standard for drinking water in China. It can be concluded that the solidified soil cistern with plastic mixture construction technology can provide available water for domestic use.

Research on Optimized Equipment System with Computer Aid for Water Purification

This paper describes pure water making equipment by using applicable datebase, computer languages and drawing software. It gives a general introduction to the systematic designing plan, the division of the different parts and their functions, and the pure water making technological process.

Performance of Subsurface Constructed Wetland in River Rehabilitation

[ Objective] This study was to research the treatment effect of different media in undercurrent wetland on contamination, so as to pro- vide reference for rehabitating water body of river along small towns. [ Method ] Three different media of gravel, cobblestone and shale were used to rehabilitate water quality of contaminated river. [ Result ] Gravel, cobblestone and shale all performed well in removing TN, TP and CODw,, in contaminated water, of which gravel stuffed undercurrent wetland run best, averagely removing 49.4% TN, 34.7% and 48. 5% COD~, respectively. [ Conclusion] Undercurrent constructed wetland can effectively improve the water quality of contaminated river, and it is cheaper in cost and simpler in operation, thus suitable for generalizing in small towns of China.

Immobilization biological activated carbon used in advanced drinking water treatment

Bacteria separated from a mature filter bed of groundwater treatment plants were incubated in a culture media containing iron and manganese. A consortium of 5 strains of bacteria removing iron and manganese were obtained by repeated enrichment culturing. It was shown from the experiments of effect factors that ironmanganese removal bacteria in the euhure media containing both Fe and Mn grew better than in that containing only Fe, however, they were unable to grow in the culture media containing only Mn. When comparing the bacteria biomass in the case ofp （DO） ：2.8 mg/L andp （DO） ：9. 0 mg/L, no significant difference was found. The engineering bacteria removing the organic and the bacteria removing iron and manganese were simuhaneously inoculated into activated carbon reactor to treat the effluent of distribution network. The experimental results showed that by using IBAC （ Immobilization Biological Activated Carbon） treatment, the removal efficiency of iron, manganese and permanganate index was more than 98% , 96% and 55% , respectively. After the influent with turbidity of 1.5 NTU, color of 25 degree and oflbnsive odor was treated, the turbidity and color of effluence were less than 0.5 NTU and 15 degree, respectively, and it was odorless. It is determined that the cooperation function of engineering bacteria and activated carbon achieved advanced drinking water treatment.

Applications of Pre-Geological Prediction in Tunnel Construction

Pre-geological prediction (PGP) is defined as the prediction of engineering geologic condition and hy-drogeological condition certain distance ahead of the working face. The purpose of this paper is to introduce mainlygeologic survey before and in excavation, to clarify their emphasis on PGP. At the same time, the technique is appliedto an engineering case, the longest highway tunnel in Gansu province. Data of geological survey of outside tunnels,sound wave detection, and geologic sketch for both tunnel face and sidewalls within the tunnel are analyzed. Afteranalyzing these data, long-term pre-geological prediction forecasting basic geological conditions of fault 4 such aslithology, scope, location, etc., and short-term and more accurate pre-geological prediction are reported.

Optimal location and effect judgment on drainage tunnels for landslide prevention

An optimal drainage tunnel location determination method for landslide prevention was proposed to solve the existing problems in drainage tunnel construction. Current applications of drainage tunnel systems in China were reviewed and the fimctions of drainage tunnel were categorized as catchment and interception. Numerical simulations were conducted. The results show that both catchment and interception tunnels have variation of the function in the simulation of monolayer model, which shows the reduction of permeability condition in lower layer. The function of catchment can be observed in the deep slope, while the function of interception is observed near groundwater source. By using the slope safety factor and discharge water amount as the objectives of optimal drainage tunnel location, and pore-water pressure in fixed node and section flux as the judgment for construction quality of adjacent drainage tunnel, the design principle of drainage tunnel was introduced. The K103 Landslide was illustrated as an example to determine the optimal drainage tunnel location. The measured drainage tunnel efficiency was evaluated and compared with that from the numerical analyses based on groundwater data. The results validate the present numerical study.

Artificial substrates preference for proliferation and immigration in Aurelia aurita(s. l.) polyps

The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the proliferation of the benthic stage(polyps). Previous experiments have mainly focused on the substrate choices of Aurelia spp. planulae. However, substrate preferences for the proliferation and immigration of polyps have not been reported. We monitored the propagation and immigration of Aurelia aurita(s. l.) polyps on two natural and nine artificial substrates at constant temperature(20±0.5°C) and salinity(30±0.5) in beakers and a glass aquarium in the laboratory, respectively. The results showed that, among artificial substrates, the highest number for polyp proliferation and immigration was found on nets, rigid polyvinyl chloride plates(RPVC), and wood. The lowest density of polyps was present on iron plates. Among natural substrates, the asexual reproduction rate of polyps on Patinopecten yessoensis(Jay, 1857) shells was significantly higher than Azumapecten farreri(Jones & Preston, 1904). On the account of the distinction in the roughness, chemical properties and biofilms of these material surfaces, bare artificial or natural substrates discriminatively affect the proliferation and the immigration of Aurelia spp. polyps at laboratory. These observations suggest that, even in the natural environment, different materials and texture may influence the composition and the abundance of the fouling communities and the assemblages of polyps and, indirectly, have effects on the amounts of released medusae.

一种空气/水混合工质热泵系统

对于传统的热泵系统一般采用非自然工质,对环境的危害大;热源主要来自于环境水的显热、湿空气的显热或全热,受环境影响大;使用温度低时装机功率大;维护和使用要求较高。针对传统热泵所存在的缺点,提出一种全新的空气/水混合工质热泵系统,该系统充分利用水结冰时放出的热量,克服上述缺陷,相对更加节能。本文对该空气/水混合工质热泵系统的组成、工作原理进行了具体分析,进而得出其相对传统热泵的优点,为自然工质热泵(制冷)系统的发展提供参考。

Spatiotemporal Variation of Riverine Nutrients in a Typical Hilly Watershed in Southeast China Using Multivariate Statistics Tools

The water quality of lakes can be degraded by excessive riverine nutrients.Riverine water quality generally varies depending on region and season because of the spatiotemporal variations in natural factors and anthropogenic activities.Monthly water quality measurements of eight water quality variables were analyzed for two years at 16 sites of the Tianmuhu watershed.The variables were examined using hierarchical cluster analysis(HCA) and factor analysis/principal component analysis(FA/PCA) to reveal the spatiotemporal variations in riverine nutrients and to identify their potential sources.HCA revealed three geographical groups and three periods.Two drainages comprising towns and large villages were the most polluted, six drainages comprising widely distributed tea plantations and orchards were moderately polluted, and eight drainages without the factors were the least polluted.The river was most polluted in June when the first heavy rain(daily rainfall > 50 mm) occurs after fertilization and the number of rainy days is most(monthly number of rainy days > 20 days).Moderate pollution was observed from October to May, during which morethan 60% of the total nitrogen fertilizer and all of the phosphorus fertilizer are applied to the cropland, the total manure is applied to tea plantations and orchards, and a monthly rainfall ranging from 0 mm to 164 mm occurs.The remaining months were characterized by frequent raining(i.e., number of rainy days per month ranged from 5 to 24) and little use of fertilizers, and were thus least polluted.FA/PCA identified that the greatest pollution sources were the runoff from tea plantations and orchards,domestic pollution and the surface runoff from towns and villages, and rural sewage, which had extremely high contributions of riverine nitrogen, phosphorus,and chemical oxygen demand, respectively.The tea plantations and orchards promoted by the agricultural comprehensive development(ACD) were not environmentally friendly.Riverine nitrogen is a major water pollution parameter in hilly watersheds affected by ACD, and this parameter would not be reduced unless its loss load through the runoff from tea plantations and orchards is effectively controlled.

FANN-Based Surface Water Quality Evaluation Model and Its Application in the Shaoguan Area

A fuzzy neural network model is proposed to evaluate water quality. The model contains two parts： first, fuzzy mathematics theory is used to standardize the samples; second, the RBF neural network and the BP neural network are used to train the standardized samples. The proposed model was applied to assess the water quality of 16 sections in 9 rivers in the Shaoguan area in 2005. The evaluation result was compared with that of the RBF neural network method and the reported results in the Shaoguan area in 2005. It indicated that the performance of the proposed fuzzy neural network model is practically feasible in the application of water quality assessment and its operation is simple.

Corrosion behavior of 907 steel under thin electrolyte layers of artificial seawater

The corrosion behavior of 907 steel under thin electrolyte layer(TEL) has been investigated by means of cathodic polarization curve measurement, electrochemical impedance spectroscopy(EIS) and scanning electron microscopy(SEM). The results show that the cathodic diffusion current density presents the variation trend of initial increase and subsequent decrease with the decrease of TEL thickness, and the maximum deposits at 58 μm. The cotangent-hyperbolic impedance(O) is rationally first introduced to study the diffusion process of the reactants through the corrosion products layer with many permeable holes. The initial corrosion rate of 907 steel under different TEL thickness increases with the decrease of TEL thickness except that of 104 μm,whereas the corrosion rate after long time corrosion can be ranked as 104 μm﹥402 μm﹥198 μm﹥301 μm﹥bulk solution.