【作者】 曹生现；

【导师】 杨善让；

【作者基本信息】 华北电力大学（河北） ， 热能工程， 2009， 博士

【摘要】 污垢是热的不良导体,它既是造成换热设备、流体机械能源浪费、环境污染的直接原因,也是严重威胁设备正常运行,降低设备利用率,引起巨大经济损失的重大诱因,因而成为各工业行业节能减排的主要目标。但鉴于污垢形成机理的极为复杂,其形成机理的研究目前还远远落后于实际应用的需求,直接研究和不断改进各种污垢对策的理论和技术,虽有治标不治本之憾,却可快捷地、至少局部满足节能减排的急需。本论文系基于作者参与“十一五”国家重点基础研究发展规划基金项目:《高能耗行业典型换热设备节能的先进理论与方法》之四“传热表面污垢生成机理与对策”[2007CB206904]的污垢对策评价和污垢特性预测部分的研究工作,将研究所得进行了较系统的总结而成。本论文的主要研究内容有:针对我国目前指导水处理剂阻垢性能评定的化工行业标准HG/T2160-1991—鼓泡法及其评定设备的不足,根据国外上世纪末提出的电导滴定法,研制了一种一体化智能型阻垢剂性能的快速评定装置。该装置基于微机技术应用平台,实现了水处理剂阻垢性能评定的全程自动化,通过检测结果的影响因素分析和实验条件优选,给出了实验室最佳测量条件,与现有各评定方法和设备相比,本仪器的精准度高、重复性好、评定快捷、操作简便、能耗小,有望成为鼓泡法评定设备的换代产品。根据碳酸钠溶液滴定氯化钙过程中溶液的光学特性,提出了基于透光率检测评定阻垢剂性能的方法,研制了集光电检测器、自动滴定控制、恒温控制和计算机一体化透光率智能检测分析评价装置,通过综合性能测试、影响因素分析和实验条件优选,给出实验室测量条件,为水处理剂阻垢效果评定提供了又一种新方法和实用装置。基于碳酸钙成垢过程动力学与电导滴定过程电导率随滴定时间变化特征的对比分析,拟定了一个碳酸钙成垢诱导期的确切定义,给出了钙离子和碳酸根离子浓度、成核速率和生长速率等参数的在线计算方法,通过电导率滴定法的静态、动态模拟实验证明了方法的可行性,为深入研究碳酸钙成垢诱导期的机理模型提供了新的简便、有效手段。为满足冷却水污垢特性预报的广泛需求,本文设计了以模拟管壳式冷却器为主要部件的动态模拟实验系统,进行指定工况和一定管材/水质配的动态模拟运行,选择与冷却水污垢特性相关性强的一组可测水质参数和模拟换热器运行工况参数为直(接检)测变量,以应用需要量大的污垢特性参数为目标(被估计)变量,利用人工智能算法建立两类变量的实验数据的定量关联式(数学模型),通过对典型工业冷却水的水样(松花江吉林市区段的水样)的连续监测和长达一年以上的实验数据处理、分析,来获取可信的水样污垢特性以相应水质参数和运行工况参数表述的数学模型。基于此法开发的污垢热阻、流动压降和腐蚀速率三个冷却水污垢特性参数为目标的污垢特性动态模拟在线预测系统,在实验验证了预测模型的重复性和设备的检测精确度后,可利用此模型和设备预测其他地域冷却水样的污垢特性,从而为水冷却器设计、管路阻力准确计算、泵的选型、阻垢缓蚀的优选提供可靠的污垢特性数据。鉴于预测系统尚未完成一个完整的运行周期,故本文只简述了预测方法和检测系统设计。更多还原

【Abstract】 Fouling is a poor heat conductor. It is not only the result of energy waste of heat exchanger and fluid machinery and environmental pollution, but also is great harm on the equipment operation and the major incentives of reducing equipment utilization and causing heavy economic losses. Therefore fouling has become the main objectives of energy saving and emission reduction in industry. In view of the fouling mechanism complexity and the dissatisfaction with researching fouling, the meaning of the research in fouling monitoring technique and equipment is great. This work was supported by a grant from the Major State Basic Research Development Program of China （973 Program） （No.2007CB206904）. The main studying contents include:In consideration of the deficiency of the traditional bubble test and manual conductometric titration, this study developed a new integrated intelligent instrument for rapid evaluation of the scale inhibitor efficiency based of the conductometric titration. It brought about automatically evaluation of the scale inhibitor efficiency with microcomputer. This paper analyzes the factors affecting detection results and optimizes experiment conditions based on a new integrated intelligent instrument for evaluating rapidly scale inhibitor performance. The instrument is high precision, good repeatability, quick-evaluation and easy-operation. It could meet the needs of the enterprises which exploit or utilize the scale inhibitor by means of the precision and rapid evaluating the scale inhibitor efficiency. This instrument may become the alternative suggestion of bubble test device.This study puts forward a new method evaluating rapidly the scale inhibitor efficiency by titration solution volume of the corresponding inflection point based on measuring transmittance as sodium carbonate titrating calcium chloride. A new integrated transmittance intelligent instrument is developed, including: photoelectric detector, automatic titration controller, temperature controller and computer. The optimal evaluating conditions are accompanied with analysing and optimizing influencing factors.Based on the comparative analysis of the essential characteristic of conductimetric titration curve with the calcium carbonate fouling process dynamic, this study proposed a precise definition for the calcium carbonate fouling induction period. The fouling induction period, Ca²⁺ and CO₃^2- concentration, nucleation rate, crystals growth rate and reaction order are determined by real time measuring titration conductivity. The results show that: the definition of the calcium carbonate fouling induction period is exact and easy detecting, the experimental unit for real-time monitoring fouling induction period and all above-mentioned parameters is convenient and feasible.In consideration of the feature predicting the cooling water fouling, this paper is designed to an dynamic experimental system simulating shell-and-tube heat exchanger. It can be used for monitoring water parameters, working conditions parameters and fouling characteristics parameters in the specified conditions. The quantitative relation of these monitoring parameters is established in the artificial intelligence algorithms. The typical industrial cooling water is continuously measured for more than a year in order to test the repeatability and precision of prediction model and the equipment, such as the water of songhua river in Jilin City. This mothed and equipment can be used for predicting or monitoring fouling thermal resistance of other geographical cooling water for the water cooler designing, accurately calculating the resistance of pipeline, pump selection and evaluating the scale inhibitor and corrosion. Due to the system unfinished a complete cycle, this paper only describes predicting method and testing system design.更多还原