生物质活性炭对亚甲基蓝的吸附平衡和动力学研究

利用玉米芯为原料制备的活性炭吸附水相中不同浓度的亚甲基蓝溶液,亚甲基蓝的初始浓度为50～250mg/L。试验条件:吸附时间为1～48h、亚甲基蓝的初始浓度为50～250mg/L、温度为30℃,得到了玉米芯活性炭吸附亚甲基蓝的吸附等温线和吸附动力学曲线。试验结果表明:Freun-dlich吸附等温线模型能够比较准确地描述亚甲基蓝在玉米芯活性炭上的吸附相平衡;准二级反应模型更准确地描述玉米芯活性炭的吸附过程;平衡时活性炭的吸附能力为48.5～225mg/g。由此可知,玉米芯活性炭对去除水溶液中的亚甲基蓝染料效果佳,是一种具有发展潜力的吸附剂。     

木薯茎秆连续热解炭吸附特性研究

以木薯茎秆为生物质原料,利用无轴螺旋连续热解装置制备木薯茎秆炭,针对原料及热解炭的组织结构、酸碱性质、表面官能团属性和表面形貌特征进行特性分析;开展木薯茎秆炭吸附溶液中亚甲基蓝、碘、苯酚和醋酸的试验,研究热解温度、粒径、振荡时间、表面清洗4个因素对炭吸附特性的影响。结果表明:随着热解温度的升高,木薯茎秆炭中挥发分含量减小,灰分及固定碳含量增大;表面逐渐形成芳香化结构,酸性官能团减少,p H值逐渐增大,碱性增强;原料表面结构不断被破坏,部分区域塌陷出现凹凸不平的表面形态。热解温度对木薯茎秆炭的吸附特性影响较大,低温热解炭的亚甲基蓝、碘和苯酚吸附值较大,高温热解炭吸附值减小,醋酸吸附值变化趋势与前三者相反。炭的粒径越小,对4种物质的吸附效果越好;振荡时间对木薯茎秆炭的吸附特性有显著影响,苯酚吸附的最佳振荡时长为60 min,醋酸为30 min。醇-水表面清洗后的木薯茎秆炭p H值减小,虽然亚甲基蓝吸附值基本不变,但碘、苯酚和醋酸吸附值增大,吸附效果改善。     

湿污泥热解残渣微观孔隙结构及吸附性能

采用管式炉热解反应器对不同含水率污泥开展高温热解制备残渣样品,采用氮气等温吸附/脱附法分析了含水率对残渣孔隙结构和表面形貌演变的影响规律,探讨了热解残渣作为废液中重金属和染料吸附剂的可行性.研究发现:与干污泥热解残渣相比,湿污泥热解残渣孔隙结构得到更充分发展,孔径2~10,nm的中孔数量明显增加,且在孔径3.75,nm出现单峰值.随着含水率增加至84%,,残渣BET比表面积、累积总孔容积、微孔孔容等呈现减小、增大再减小的趋势;热解残渣对废液中Cu2+、Cr6+以及亚甲基蓝、孔雀石绿染料均有一定的吸附能力.     

松子壳热解炭活化特性研究

以松子壳为原料,采用常规热解法得到松子壳炭,利用水蒸气活化的方法制备了微孔率较高的活性炭,并测定其吸附能力。利用红外光谱(FT-IR)、氮气吸脱附曲线、扫描电镜(SEM)对热解炭及相应活性炭进行了表征。最佳活化工艺为活化温度850℃,活化时间60 min,水蒸气流量0.3 g/min。在该条件下松子壳活性炭得率为34%,亚甲基蓝吸附值为186 mg/g,碘吸附值为1 097 mg/g,比表面积为1 094.895 m2/g,平均孔径为3.95nm。微观结构分析表明,热解炭已经具备一定的孔隙结构,活化过程中活化剂能够有效去除堵塞热解炭孔隙的杂质和不定型炭,形成丰富的微孔结构和少量的介孔、大孔。该研究为松子壳活性炭的制备提供了理论依据。     

热解温度对污泥热解半焦产率与特性影响的研究

利用固定床反应器对3种不同来源的污泥进行热解,研究了热解终温对污泥热解半焦产率、热值和比表面积的影响。研究结果表明：随着热解终温的提高,污泥热解半焦的产率逐渐降低;随着半焦中挥发分的减少和灰分含量的增加,半焦的热值降低;半焦的比表面积呈现先增加后降低的趋势,3种污泥在热解终温分别为900,800,700℃时获得的半焦比表面积达到最大值,分别为64．88,44．26,23．75m^2／g。     

稻秆热解半焦吸附能力的研究

通过研究生物质半焦对甲醛和氨的吸附,考察了热解温度和化学处理对半焦吸附能力的影响;同时采用热重分析和酸碱滴定的方法研究了半焦表面酸碱中心的强度和浓度.结果表明:升高热解温度,半焦的比表面积变大,可以吸收更多甲醛和氨;半焦经酸洗后吸附甲醛的能力明显下降,而吸附氨的能力基本不变;经碱洗后对于氨的吸附能力明显下降,而对于甲醛的吸附能力基本不变.随着热解温度的提高半焦表面酸性中心浓度下降,而碱性中心浓度基本不变.     

2021 年 1 期目录

以棉涤废料为炭前驱体,利用醋酸钙为模板剂,采用单因素法考察在不同热解温度、质量比和热解时间下制得的介孔炭对亚甲基蓝和四环素的吸附性能,从而筛选得到最佳制备工艺参数,同时利用氮气吸附?脱附曲线、扫描电镜、X射线衍射、红外光谱进行物化性能分析,并研究其对水中四环素的吸附规律。结果表明,制备棉涤废料基介孔炭的最佳工艺参数为：热解温度为800 ℃、醋酸钙和棉涤废料质量比为1.5∶1、热解时间为1.5 h。醋酸钙模板剂成孔性能优异,制得的介孔炭总比表面积高达1 106.630 m2·g?1,介孔率达到62%,对水中四环素的吸附过程符合Langmuir模型,为自发吸附,最大吸附值为506.40 mg·g?1。     

生物质热解半焦特性及其水蒸气吸附规律

选择杨木和松木两种木材作为热解原料,在常压下250~550℃内选取4个温度进行热解,并对生物半焦的性质进行分析。通过对生物半焦比表面积、表面官能团、孔隙率、氧碳比、氮碳比等性质的分析,研究热解得到的生物质半焦水蒸气吸附的影响规律。研究发现:生物半焦对水蒸气的吸附并非由单一性质所决定,而是受到比表面积、表面官能团、孔隙率等因素共同决定。     

熔盐热裂解水稻秸秆制备活性炭及其吸附性能

以ZnCl2-KCl混合熔盐(ZnCl2和KCl的物质的量之比为7∶6)热裂解水稻秸秆并进一步用ZnCl2活化热裂解残炭得到活性炭,考察热裂解温度、N2流量、活化时间、活化温度、盐炭比和原料粒径等因素对制备活性炭的得率和吸附性能的影响。结果表明:试验条件下活性炭得率变化不大,均大于30%,但其碘吸附值、亚甲基蓝吸附值则变化明显;450℃、N2流量为150Lh是较佳热裂解条件。活化过程中,活化温度、活化时间和盐炭质量比均对活性炭的吸附性能存在影响,影响程度依次减小,最佳活化条件为活化温度600℃、活化时间1h、活化盐炭质量比3;在20~100目范围内,随着原料粒径的减小,相同条件下制得的活性炭的碘吸附值和亚甲基蓝吸附值均增大。最优试验条件下所制备活性炭的亚甲基蓝吸附值为118.31mg/g,碘吸附值为721.42mgg,比表面积为1675.9m2g。     

氧化石墨烯的改良制备及吸附性能研究

在改良hummers法制备氧化石墨烯的基础上,对制备过程各步骤进行精准化控制,总结了氧化石墨烯在制备过程中出现的问题,分析成因并进行改进,得到了一种鳞片石墨制备氧化石墨烯的简便、低成本且环保的方法。利用制得的氧化石墨烯对亚甲基蓝模拟染料废水进行吸附实验研究,结果表明,氧化石墨烯投加量为0.1 g,转速为300 r/min,时间为90 min,亚甲基蓝的去除率达到98.7%。     

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.     

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.     

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.     

液压系统常见的故障诊断及处理

任何工程机械式液压设备使用时出现故障是不可避免的。但是怎样确定故障的原因及找到好的解决方法，这是使用者最关心的问题。讲述了液压系统常见的故障及其排除方法。     

Economie d'énergie en trigénération

Trigeneration is defined as the production of three useful forms of energy—heat, cold and power—from a primary source of energy such as natural gas or oil. For instance, trigeneration systems typically produce electrical power via a reciprocating engine or gas turbine and recover a large percentage of the heat energy retained in the lubricating oil, exhaust gas and coolant water systems to maximize the utilization of the primary fuel. The heat produced can be totally or partially used to fuel absorption refrigerators. Therefore, trigeneration systems enjoy an inherently high efficiency and have the potential to significantly reduce the energy-related operation costs of facilities. In this paper, we describe a model of characterization of trigeneration systems trough the condition of primary energy saving and the quality index, compared to the separate production of heat, cold and power. The study highlights the importance of the choice of the separate production reference system on the level of primary energy saving and emissions reduction.     

Mineralogical characterization of the intraseam layers of Lofoi lignite deposits in Florina basin (western Makedonia,northwest Greece)

The mineralogical composition of intraseam layers from Lofoi lignite deposits (northwest Greece) is the subject of the present study. The samples were examined by means of X-ray diffraction (XRD), thermo-gravimetric (TG/DTG) and differential thermal analysis (DTA), and Fourier transform infrared (FT-IR) spectrometry. The clay minerals prevail in most samples, with illite-muscovite being the dominant phase, and kaolinite and chlorite being the other major clay components. No smectite was found. Quartz and feldspars, dominate in two cases. The studied materials are characterized as clays to clayey sands, showing significant similarities with the intraseam layers of the adjacent Achlada lignite deposits.     

Innovative methodologies in renewable energy: A review

This paper is concerned with innovative approaches to renewable energy sources computation methodologies, which provide more refined results than the classical alternatives. Such refinements provide additional improvements especially for replacement of fossil energy usages that emit greenhouse gas (GHG) into the atmosphere leading to climate change impact. Current knowledge gap among each renewable energy source calculation is rather missing fundamentals of plausible, rational, and logical explanations for the interpretation of results. In the literature, there are rather complicated and mechanically applicable methodologies, which require input and output measurement data match with missing physical explanations. The view taken in this review paper is to concentrate on quite plausible, logical, rational, and effectively applicable innovative energy calculation methodologies with simplistic fundamentals. For this purpose, a set of renewable energy methodological approaches is revisited with their innovative structures concerning solar, wind, hydro, current, and geothermal energy resources. With the increase in the renewable energy utilizations to combat the undesirable impacts of global warming and climate change, there is a need for better models that will include physical environmental conditions and data properties in the probabilistic, statistical, stochastic, logical, and rational senses leading to refined and more reliable estimations with application examples in the text. Finally, new research directions are also recommended for more refined innovative energy system calculations.     

Constrained Optimization of Heat Transfer from an Extended Surface

Two different zero‐order optimization techniques are used to maximize the rates of heat transfer from a fin assembly of a specified cost and in the shape of several annular fins that are mounted on a central stem. The problem is formulated to account for two‐dimensional steady‐state heat transfer that is limited by several inequality constraints. The dimensionless governing equations are used to identify the relevant decision variables. The number of fins making up the assembly is treated as an input parameter. A digital computer is used to determine the required temperature distributions and to implement the optimization search algorithms. Three different fin materials are assessed—aluminum, copper and carbon steel. Design optimizations of the extended surface assembly were made over a range of operating conditions, encompassing several different convection heat transfer coefficients that are representative of free and forced convection in air, and several different overall temperature differences between the substrate surface and air. A few recommendations based on trends in the predicted results are given. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(6): 504–521, 2014; Published online 3 October 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21093     

CY6D78Ti型柴油机的开发研制

本文介绍了CY6D78Ti型柴油机的开发研制过程及现状,CY6D78Ti型柴油机能满足国内中、重型卡车和豪华客车市场对柴油机动力性、经济性、可靠性的需求。由于该机型的高档配置,保证了其排放达到欧Ⅱ标准,同时为进一步提高性能、降低排放,采用电控及高压共轨等技术手段搭建了平台。     

我国车用柴油机的技术现状及发展趋势

本文根据国内外信息和资料，分析了我国目前车用柴油机制造技术方面与国际水平所存在的差距，预测今后若千年内车用柴油机要向节能降耗、应用增压技术、提高可靠性、降低排放、采用电控技术方面发展，以尽快接近和赶上国际先进水平．