直接接触式气体水合物蓄冷特性的理论及实验研究--摘要.doc

摘 要 随着我国市场经济的快速发展，电力紧缺已成为制约国民经济发展的瓶颈。一方面电力的需求越来越大，另一方面，电力使用的不平衡，峰谷负荷差不断增大，资源得不到有效利用。空调蓄冷技术就是利用夜间低谷用电时段的电力储存冷量，在白天用电高峰时释放这些冷量作为空调冷源，因而蓄冷空调能够有效地“移峰填谷”，均衡电网的供电负荷。气体水合物蓄冷技术，因其相变潜热与冰相当，相变温度在513之间，与常规空调兼容性好，化学稳定性好等优点，是公认的前景广阔的新一代蓄冷空调技术。论文首先对空调蓄冷的背景和蓄冷技术方法进行了介绍，接着详细说明了直接接触式气体水合物实验台的搭建方法、系统测试和数据采集原理。直接接触式气体水合物蓄冷实验台包括制冷系统，可视化水合物反应罐，可视化水合物储存罐和空调末端放冷系统。该实验台具有以下特点： 1. 国内首例具有实用意义的直接接触式气体水合物/二元冰 蓄放冷实验装置，采用直接接触式提高了换热效率，气体水合物反应速度快，蓄冷密度高。2. 系统采用了可视化设计。在反应罐、储存罐、斜管等处敷设透明玻璃，能够直接观测到气体水合物的反应过程、储存及释冷过程，并可摄像记录。3. 实验台测试系统采用组态软件进行二次开发，自动化程度高，整套装置设计紧凑，实用性强。论文第四章对气体水合物的晶体结构和热力性质进行了研究，并对气体水合物的相平衡、直接接触式气体水合物反应的传热传质等问题进行了理论探讨。第五章则通过采用制冷剂R11进行水合物蓄冷实验，对喷头的形式、位置、制冷剂流量及不同浓度的乙二醇表面活性剂对气体水合物蓄冷过程的影响进行了详细的分析。实验得出结论如下：（1）对喷喷头的综合换热效果最好；（2）制冷剂流量增大可使水合物反应速度加快；（3）加入表面活性剂乙二醇后，气体水合物的临界分解温度下降，成核温度也要降低，诱导时间缩短，成核过冷度要比未加入表面添加剂时增大。水合物生成过程温度相对平滑，水合物冰晶较细，核化点容易形成，气体水合物生长的更加致密结实。论文最后对水合物蓄冷实验研究进行了总结和展望，对实验过程中出现的问题提出了自己的合理化建议。关键词 直接接触式，气体水合物，蓄冷，表面活性剂ABSTRACTWith the rapid development of the market economy in China, the lack of electric power is now a bottleneck which restricts the development of the national economy. On the one hand, the demand of the electric power increases continuously, on the other hand, the imbalance utility of electric power and the increasing load between peak and off-peak time causes the waste of the electric power resource. Cold storage air conditioning technology uses off-peak power during nighttime to store cold energy and release it as a cold resource for air conditioners during daytime with little use of on-peak electricity. So cold storage air conditioner can shift peaking load efficiently and equilibrate the electric load.Gas hydrate cold storage technology is recognized as a new generation air conditioning technology with bright prospect. It is because that the gas hydrate has comparative latent heat as that of the ice. its phase changing temperature is between 513, it is compatible with the conventional air conditioner and it has a good chemical stability .First this thesis introduces the background and technology methods of the cold storage air conditioner, then in detail it shows how to build this direct-contact gas hydrate cold storage experimental installation, and the principle of data acquisition and test of the system. This direct contact gas hydrate cold storage installation is composed of a refrigerating system, a viewable hydrate reaction tank, a viewable hydrate storage tank and a cold releasing terminal system. This experimental installation has the characteristics as following:1. It is the first domestic direct contact gas hydrate /binary ice cold storage/release experimental installation with practical value, using a direct contact method improves the heat exchange efficiency, it has got a quicker reaction velocity and a heavy cold storage density.2. The system uses a viewable design. Transparent glasses are installed with the reaction tank, storage tank and the inclined tube with which we can observe the course of the hydrate reaction, storage and heat release directly, also we can take photos and record the process of the hydrate reaction.3. With a secondary programming to the KINGVIEW configuration software, the testing system has a highly automatic. The installation is compactly designed with practical use.In the 4th chapter, it describes the crystal instruction and the thermodynamic characteristics of the gas hydrate, it also discusses the phase equilibrium of hydrate, the heat and mass transfer of direct contact heat exchange in theory. Chapter 5 gives a detailed analysis including the effect of the sprayer shape and position, the refrigerant flow and different concentration glycol surface additive to the hydrate cold storage process with R11 experiments. The conclusions of the experiments are as following:(1) The opposite two sprayers can get the best heat exchange efficiency generally.(2) An increase refrigerant flow can speed the progress of the hydrate reactions.(3) With the help of the glycol surface active additive, the critical melting temperature of the gas hydrate drops, also the nucleating temperature gets low, the inducement time is shortened, and the nucleating super-cooling degree increases comparing to the condition without glycol. The fluctuation of the temperatures get smoothed during the growing process of hydrate, the hydrate crystal gets fine, also with the help of glycol, the nucleating points can form easily and the hydrate can grow a heavy density. In the last chapter the thesis comes to a conclusion of the experiment of the gas hydrate cold storage, also it shows the prospect of this technology. The author gives his own reasonable advice for the problems existing in the experiment.KEYWORDS: direct-contact, gas hydrate, cold storage, surface active additive目 录第一章 引言1.1 概述1.2 蓄冷空调的产生和发展背景1.3 国内外蓄冷技术的研究及应用现状1.4 气体水合物蓄冷技术的研究进展1.5 本论文进行的主要工作11241112第二章 直接接触式气体水合物蓄冷实验台的工作原理和搭建 2.1 直接接触式气体水合物蓄冷实验台工作原理2.2 实验台各系统的设备组成2.3 水分离装置的设计和实现14141522第三章 实验台测试及数据采集系统 3.1 实验台测试要求3.2 实验台测试方案3.3 数据采集及误差分析3.4 组态软件的开发 2424252730第四章 直接接触式气体水合物蓄冷特性的理论研究 4.1 气体水合物的结构和蓄冷机理4.2 气