太阳能吸附制冷用复合吸附剂制备及其吸附机理探讨

以乙醇为吸附质，选取13X分子筛、凹凸楱土和氯化锶等为主要吸附材料．通过混合法制备了一系列有着优良吸附能的复合吸附剂。测定了乙醇在主要吸附材料和自制复合吸附剂上的吸附量，用TG-DTA法对主要吸附材料的热稳定性和自制吸附剂DTA脱附乙醇峰端温度进仃了分析.对吸附剂原料复合比例和扩孔剂种类等制备条件进行了实验研究。结果表明：自制复合吸附剂比单一吸附材料对乙醇确着更大的吸附能力；DTA分析的脱乙醇峰端温度明显低于单一吸附材料；加入扩孔剂E1或E2，可增加自制复合吸附剂孔容和孔径，改善其吸附性能；自制复合吸附剂对乙醇的吸附量显著高于活性炭。其中，M4-0003和M1-0001复合吸附剂对乙醇的平衡吸附量约为活性炭的2．5～4倍；M1-0001—乙醇工质对的吸附制冷量是活性炭—乙醇的2～6倍。对吸附剂复合的机理初步探讨表明：增加复合吸附剂弱吸附中心数，可降低其脱附温度。     

活性炭纤维吸附低体积分数苯的实验研究

研究了黏胶基活性炭纤维(activated carbon fiber, ACF)对非极性苯蒸汽的吸附.活性炭纤维比颗粒活性炭具有更高的吸附能力和更快的吸附动力且能有效去除挥发性有机化合物(volatile organic compounds, VOCs),活性炭纤维吸附剂其比表面积与孔结构通过氮吸附来表征.活性炭纤维样品上的苯吸附与脱附则通过热重方法测量,用DR方程对实验得到的吸附等温线进行拟合.实验结果表明,吸附量随活性炭纤维比表面积的增加而增加,而脱附过程则需100 min左右.     

活性炭吸附储存H2的研究

通过几种储氢方式的对比,论证了以活性炭作为吸附剂储存H_2的可行性;着重阐述了影响H_2吸附储存的因素,即活性炭的比表面积、活性炭的微孔容积和活性炭表面含氧官能团对H_2吸附储存量的重要影响。综述了活性炭吸附储存H_2的研究,同时概括了H_2吸附储存的理论研究并展望今后发展及研究的方向。     

垃圾填埋气中的甲苯对脱碳提纯吸附剂工作性能的影响

文章以甲苯作为垃圾填埋气中的典型挥发性有机物,选择了3种可用于吸附脱碳提纯工艺的吸附剂(13X分子筛、5A分子筛和活性炭),研究了甲苯在这3种吸附剂上的吸附-脱附特征,以及吸附剂在吸附甲苯后的CO_2吸附性能。研究结果表明:真空条件下,吸附剂的甲苯脱附量很小,在吸附-脱附循环过程中,吸附剂中的甲苯含量较高且保持稳定;当吸附剂吸附甲苯后,其对CO_2的吸附能力均有所下降,其中13X分子筛和活性炭的CO_2吸附能力显著下降,5A分子筛的CO_2吸附能力下降程度较小,吸附剂对CO_2吸附能力的下降程度,与其对甲苯的吸附量呈正相关。     

新型复合吸附剂SiO2·xH2O·yCaCl2与常用吸附剂空气取水性能的对比实验研究

提出了一种便携式吸附空气取水器 ,并为其提出了一种新型复合吸附剂SiO2 ·xH2 O·yCaCl2 。介绍了这种吸附剂的配制方法 ,分析了它吸附湿空气中水蒸气的原理。通过实验表明 :在空气温度恒为 2 5℃、相对湿度 4 0 %的条件下 ,这种复合吸附剂的平衡吸附量we(H2 O干吸附剂 )可达 0 .4 ,是粗孔球形硅胶的 5 .7倍、细孔球形硅胶的 2 .1倍、人工沸石 13X的 1.9倍、椰壳活性炭的 6 .8倍。通过对比分析它们的吸附速度曲线表明 :这种复合吸附剂的吸附特点是吸附量大、吸附速度快。分析结果表明 :采用这种复合吸附剂的空气取水器即使在我国西北地区 7月份的干燥气候条件下也能够有很高的出水量。而且这种复合吸附剂的解吸温度低 (6 0～ 80℃ ) ,可用太阳能加热解吸 ,是一种理想的取水用吸附剂     

吸附天然气做汽车燃料技术的发展

吸附天然气做汽车燃料的技术关键是研制有效的天然气吸附剂。本文从天然气吸附剂的选择、研制，填充方法，吸附性能及微观机理等方面概述了天然气吸附剂的研究开发状况，提出了这种吸附剂应具备的性能指标和相应吸附理论的发展方向。     

太阳能平板型吸附床强化传热的分析

通过对太阳能平板型吸附床内温度分布的计算,分析了吸附床中嵌入金属助片和吸附剂（活性炭）中掺入铜粉等提高其导热系数的强化传热 方法的效果,认为当肋片的间距在6cm左右或增大吸附剂的导热系数到0．4－0.6W/(m.℃）时,吸附床内厚度方向的温度分布近乎直线,温度梯度较小,同时,胁片的热容对吸附床的整体温度的提高有很大影响。     

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。     

吸附式制冷机及空调/热泵的运行实验和性能改进

研制了一台采用螺旋板式吸附器的连续回热型吸附式制冷机和一台采用板翅式吸附器的空调／热泵,给出了实验数据。吸附式制冷系统采用活性炭－甲醇吸附工质对,以９０－１００℃絷不作为热源,实验得到单位质量活性炭的制冷能量密度为：制冰机每ｋｇ吸附剂日制冰２．６ｋｇ,空调／热泵组在空调工况下每ｋｇ吸附剂制冷功率为１５０Ｗ。     

树脂对沼气发酵的影响

选用比表面积基本一致而表面电荷不同的树脂作为吸附剂,研究了树脂对沼气发酵的影响。研究结果表明,不同吸附剂对沼气产气量影响排序为强酸性树脂强碱性树脂活性炭弱酸性树脂吸附树脂空白弱碱性树脂。添加吸附剂对厌氧发酵后发酵液的pH值没有明显影响,可初步排除添加树脂是通过解除产物抑制或改变发酵液pH值来影响沼气发酵的可能。     

Research and development of consolidated adsorbent for adsorption systems

Adsorption heat pump and refrigeration systems are noiseless, non-corrosive and environment friendly. For these reasons the research activities in this sector are still increasing to solve the crucial points that make these systems not yet ready to compete with the well-known vapor compression system. There is an increasing interest in the development and use of adsorption chillers due to their various economic and impressive environmental benefits, enabling solar energy or waste heat to be used for applications such as district networks and cogeneration plants. In order to increase the cooling power, much effort has been devoted to enhance materials heat transfer properties. Consolidated adsorbent could be the solution. This paper provides a literature review on current progress of consolidated adsorbent for adsorption systems. A number of consolidated technologies of adsorbent are discussed. The related work at our laboratory is also discussed.     

沸石分子筛-水吸附工质对的吸附性能及导热性能

吸附工质对的吸附和传热性能是研究吸附式干燥、除湿及制冷的重要基础，由于吸附量与导热系数和吸附材料的性质、温度、压力等许多因素有关，需要通过实验来确定。该文通过对几种沸石分子筛的性能实验研究，测定了其最大吸附量、密度、吸附等压线及导热系数等一系列性能参数及其影响因素，并给出了实际循环过程中吸附床的温度、压力与吸附量之间的关系。研究表明沸石对水的吸附基本满足D—A方程，而沸石导热系数受温度以及吸附量的影响较大，随着温度及吸附量的增加而增加。     

新型吸附式制冷系统吸附床的研究进展

吸附床的传热传质性能是提高吸附式制冷效率的关键,优化吸附床的结构能够有效提高整个吸附床的传热传质效率,减少热量损失,提高系统的制冷效率（coefficient of performance, COP）和单位质量吸附剂制冷量（specific cooling power, SCP）。本文介绍了近年来几种新型吸附床的类型,综述了吸附剂侧的固化吸附剂和涂层吸附剂,以及换热器侧的新型换热器结构。最后阐述新型吸附床的未来发展方向和研究重点。     

A non-uniform temperature non-uniform pressure dynamic model of heat and mass transfer in compact adsorbent beds

This paper discusses a new dynamic two-dimensional model for the simulation of innovative consolidated-type adsorbent beds to use in adsorption energy systems. It consists of a cylindrical pipe, conveying the thermal vector fluid, coated with a layer of consolidated zeolite.The governing equations take into account with detail the transport phenomena and are solved according to advanced numerical methods in the time and space domain.A parametric analysis is carried out for the evaluation of the overall system performance sensitivity to the most meaningful parameters, such as adsorbent bed thickness, water vapour permeability and heat transfer coefficients. A critical discussion is also made about the most credited adsorbent bed arrangements, i.e., pure powder, consolidated powder and metal bound consolidated powder. It was possible to demonstrate that the adsorbent bed, of consolidated powder type, proposed by the CNR-ITAE Lab, performs better than other bed arrangements available in the literature.     

Comparative study on adsorbent characteristics for adsorption thermal energy storage system

The adsorption performance of the thermal energy storage (TES) system changes depending on the material properties of the adsorbent itself, but the change of the hardware structure can also substantially change the adsorption characteristics. In this study, a laboratory‐scale adsorption‐based TES system was constructed, and the adsorption performance of three adsorbents was evaluated in the same system to compare the adsorption performance between adsorbents. The adsorption characteristics of silica gel, zeolite 13X, and 4A, which are the most preferred adsorbents in the physical adsorption‐based TES system, were selected for evaluation. Experiments with each adsorbent were performed, including heat recovery to evaluate the heat transfer effect and the amount of heat recoverable in the actual TES system. Experimental results have identified several key characteristics of the adsorption and performance of each adsorbent in the TES system, as well as operating parameters that determine the influence of adsorption performance on the TES system. The actual energy storage density of the adsorbent is affected not only by the enthalpy of adsorption of the material itself but also by other factors. These factors include the difference in thermal conductivity that causes a difference in temperature distribution and the magnitude of mass transfer resistance due to the shape of the adsorbent particle and the actual TES system reactor structure. If the reaction heat generated during the adsorption reaction cannot be effectively released, the adsorption performance is significantly lowered due to the increased temperature of the reactor inside. This phenomenon was commonly observed in adsorbents examined in the present study. The uptake amount, X [g/g], was increased by allowing the inside of the reactor to be maintained at a lower temperature through heat recovery. In case of silica gel, the temperature rise during adsorption reaction is not high due to the difference of isotherm characteristics compared with zeolites, but it is possible to absorb more amount of adsorbate and to recover heat for a longer time. The energy storage density is affected by the temperature increase effect and the uptake amount of adsorbate during the adsorption reaction. The experimental results show that the energy storage density of zeolite 13X is 15% and 28.7% higher than that of silica gel and 4A, respectively, and the temperature rise due to heat generation during adsorption reaction is also high, which is advantageous in adsorption TES system performance.     

降低吸附式制冷系统驱动热源温度的研究进展

吸附式制冷是一种环境友好的制冷方式,可以利用低品位热能提供冷量,因此具有重要的节能意义。目前,吸附式制冷技术在太阳能热利用、工业余热利用等中低温余热领域已有应用,但对低于60℃热源的利用实例较少。降低吸附式制冷系统所需的驱动热源温度是扩大吸附式制冷系统使用范围的重要手段。吸附式制冷系统所需驱动热源温度与系统循环方式、吸附剂性能等因素密切相关。从二级/多级吸附式制冷循环、表面酸性强度与孔结构等影响吸附剂再生温度方面阐述了降低吸附式制冷系统驱动热源温度技术的国内外研究现状。分析结果显示,多级循环吸附式制冷系统可以降低装置的驱动热源温度,但装置结构较为复杂;低再生温度吸附剂能够拓宽吸附式制冷装置的驱动热源温度范围,吸附剂的脱附温度与表面极性、酸性、孔结构等参数有关,对吸附剂进行改性,吸附剂极性弱、酸性低的表面特性有利于降低脱附温度。另外,还介绍了数据中心余热驱动的吸附式制冷技术。开展降低吸附式制冷系统驱动热源温度的研究为低温余热高效利用提供了技术参考。     

吸附制冷系统吸附床传热过程的数值模拟

为缩短吸附制冷周期,采用两床交替吸附/解吸结构,并采用管内走传热介质,管外填充吸附剂的吸附式制冷系统。建立了相应的数学模型。用数值方法对模型进行了求解,着重对吸附床温度场分布进行了数值模拟,并对吸附床内压力,某些点温度以及吸附量随时间的动态变化进行了模拟,得出的结果与实际情况吻合较好,说明此吸附制冷系统有较好的传热效果,为吸附床的优化设计提供了参考依据。     

基于平行流铝扁管吸附床传热性能的模拟研究

吸附床是吸附式制冷系统的关键部件。吸附床的换热能力对吸附式制冷系统的各项性能有显著影响。文章针对应用于吸附床的传统换热器和扁管换热器的不足之处,设计出一种新型平行流铝扁管吸附床,并建立了该吸附床的二维传热模型,以温度随时间的变化情况为分析指标,分析翅片的间距、高度、厚度,以及吸附剂体积分数等因素对吸附床传热性能的影响,从而优化调整吸附床的结构,提高其换热性能。分析结果表明:当翅片高度约为70 mm时,吸附床的换热能力达到峰值;当翅片厚度大于1.5 mm时,翅片厚度的增加对吸附床传热性能的影响比较微弱;当吸附剂体积分数由0.25逐渐增大至0.45时,吸附剂的等效传热系数约增加了50%。     

余热制冷用氯化钙_硅胶复合吸附剂的制备及性能研究

为了开发出利用余热进行吸附制冷的高性能吸附剂,采用浸渍法在真空下将氯化钙担载于粗孔硅胶上,制备了硅胶/氯化钙复合吸附剂,测试了复合吸附剂的吸附等温线和吸附速率,测试结果表明:浸渍法得到的复合吸附剂对水具有更大的吸附能力,在20%的湿度下,复合吸附剂在2h的吸附量为15.64 g/100 g吸附剂,是单一硅胶在相同条件下吸附量的8.06倍。用制备的复合吸附剂制作了一台小型吸附制冷机并进行了测试,当热源温度为90℃,冷却水温度为35℃时,在整个循环周期内(15 min),制冷功率为0.705kW,单位质量吸附剂的制冷功率(SCP)为70.51 W/kg,COP为0.25。     

太阳能固体吸附式制冰机热动力学性能分析模型及实验

分析了太阳能固体吸附式制冷装置中吸会床的传热传质计算过程,给出了求解模型的具体方法,运用数值传热学的方法,计算了在一定日照国徽能量条件下,系统装置的吸附床内的温度场分布,实验表明,所建立的模型能对太阳能固体吸附式制冷装置进行了性能动态模拟,为系统装置的优化设计提供了参考。