有机热载体炉积碳检测技术及安全评价研究

发布时间：2019-06-02 14:50

【摘要】：摘要：从国家质量监督检验检疫总局近五年的特种设备事故情况通报可知,尽管每年的万台设备事故率有所下降,但是在锅炉台数有所减少的情况下锅炉事故例数仍高居不下。对事故通报原因进一步分析得知：中小工业锅炉中有机热载体炉的火灾事故一直高发。为解决有机热载体炉积碳和火灾事故,本论文依托质检公益性行业科研专项(201210080)“有机热载体炉安全评定及积碳在线检测关键技术研究”和质检总局科技计划类项目(2013QK212)“导热油炉基于FLUENT的流场数学建模和仿真研究”这两个国家质检总局项目,在系统而全面地检索及深入分析以前的学者已经取得系列研究成果的基础上,采取理论分析、试验模拟仿真与实际检测应用三者相结合的研究方法,针对有机热载体炉积碳检测、介质FLUENT流场分布和安全评价三方面进行了深入研究,取得的主要创新性成果如下： 1.统计分析了国内近十年有机热载体炉火灾事故以及有机热载体炉积碳检测控制技术的相关论文,阐述了有机热载体炉火灾事故的主要形成原因,并指出有机热载体炉积碳层是导致有机热载体炉火灾的关键因素。 2.根据有机热载体介质的物理化学性质和有机热载体炉系统的特殊性,分析了有机热载体积碳形成机理和有机热载体炉运行机理,并提出一种基于超声导波的积碳层厚度检测方法。 3.设计组装了一套有机热载体炉积碳检测系统,试验研究了超声导波的截止频率、跃迁频率和群速度这3个表征参数与积碳层厚度变化的关系。结果表明：可用超声导波的群速度与积碳层厚度变化的单调性规律来检测积碳层的厚度,并通过空管中的群速度频散曲线的拟合试验进一步论证该检测方法的可行性。 4.为识别积碳检测中超声导波的模态类别,故利用时频分析对炉管中多个模态进行比较分析,并结合时频分析的主要能量分布图与数值模拟的频散曲线中L(0,2)模态走势的拟合,推断出的主要波形模态为L(0,2)模态,通过时差法计算群速度和实验群速度的的相对误差仅为1.88%-3.48%。 5.通过模拟附着物超声导波积碳检测试验得到：信号为5周期,频率为500kHz,峰峰值为200mV,激励出的L(0,2)模态波的群速度检测盲区为探头布置间距小于350mm,有机热载体炉管中积碳层超声导波检测探头布置最佳检测距离为40cm。从信号的信噪比、时域和频域特征验证了检测的最佳周期为5周期；可用环氧树脂添加碳氢化合物和模拟积碳层,并成功激励出了L(0,2)模态。当探头间距40cm,检测周期取5周期时,用试验论证了L(0,2)模态在积碳管中的群速度较空管中的群速度减小7.65%,进一步论证了可用空管和积碳管群速度的变化关系来检测有机热载体炉管道中的积碳层。 6.将人机工程学原理运用到有机热载体炉运行风险评价中,得出运行中人机环境指标的权重分别为：1.830、1.293、1.749,比较得出入和环境这两个指标比有机热载体炉设备本体的权重大0.5左右。这表明有机热载体炉运行风险需要更多关注人员素质和环境管理。然后通过国内外有机热载体炉火灾事故统计调查,运用鱼刺因果分析法定性地分析了事故原因,再结合事故树分析和事件树分析方法,找到引发火灾事故的基本因素、关键因素(如：有机热载体泄漏)及其重要度和关键概率度。 7.运用FLUENT对盘管式有机热载体炉的盘管不同流速和不同积碳层厚度情况下进行模拟研究并发现：当无积碳层时,盘管内有机热载体流速分布靠管壁两侧的有机热载体流速较慢,尤其是辐射管壁侧更为明显；有机热载体管内流速从管壁往管子中心逐渐增大,辐射段因为有辐射热侧的紊流层比保温侧的紊流层区域更大；靠近辐射管壁,层流与紊流交界处,有机热载体介质流速接近最大。当入口流速为1.0m/s时,随着导热油流速的降低,有机热载体处于劣化变质状态局部流动随着管径和流速的变化而呈现一定规律的变化,碳层越薄越有利于流场的均匀和液膜温度不超温。最后,在基于有机热载体炉积碳检测、安全评价和FLUENT流场模拟这三者综合构建的基础上,提出了有机热载体炉风险控制的管理模式和有机热载体炉安全立法的建议。
[Abstract]:Abstract: According to the information of special equipment accident in recent five years from the General Administration of National Quality Supervision and Inspection and Quarantine, the number of boiler accidents is still high in the case of a decrease in the number of boilers in the event of a decrease in the number of unit accidents per year. Further analysis of the cause of the accident shows that the fire accident of the organic heat carrier furnace in the medium and small industrial boilers has been high. In order to solve the carbon and fire accidents of the organic heat carrier, this paper, on the basis of the technical research special (201210080) of the quality inspection and public welfare, the key technology of the safety evaluation of the organic heat carrier furnace and the on-line detection of the product-carbon on-line detection and the technical plan project of the General Administration of Quality Inspection (2013 QK212). The heat transfer oil furnace of the heat transfer oil furnace is based on the FLUENT-based flow field mathematical modeling and simulation study. On the basis of systematic and comprehensive search and in-depth analysis of the series of research results of the previous scholars, the research methods of the combination of the theoretical analysis, the test simulation and the actual detection and application are adopted, aiming at the carbon detection of the organic heat carrier furnace product. The three aspects of measurement, medium FLUENT flow field distribution and safety evaluation have been deeply studied, and the main innovative achievements have been obtained. 1.1. Statistical analysis of the fire accident of the organic heat carrier furnace in the last ten years and the phase of the carbon detection control technology of the organic heat carrier furnace The main reason of the fire accident of the organic heat carrier furnace is discussed, and it is pointed out that the organic heat carrier furnace product carbon layer is the key to the fire of the organic heat carrier furnace. 2. Based on the physical and chemical properties of the organic heat carrier medium and the particularity of the organic heat carrier furnace system, the mechanism of the formation of the organic heat carrier and the operation mechanism of the organic heat carrier furnace are analyzed, and a carbon layer thickness based on the ultrasonic guided wave is proposed. 3. A set of organic heat carrier furnace product carbon detection system was designed and assembled. The cutoff frequency, transition frequency and group velocity of ultrasonic guided wave were studied. The results show that the thickness of the carbon layer can be detected by the monotonicity of the group velocity of the ultrasonic guided wave and the change of the thickness of the carbon layer, and the test of the group velocity dispersion curve in the hollow tube is further demonstrated. 4. In order to identify the mode category of ultrasonic guided wave in the detection of accumulated carbon, the multiple modes in the furnace tube are compared and analyzed by time-frequency analysis, and the main energy profile of the time-frequency analysis and the frequency dispersion curve of the numerical simulation are combined to L (0, 2) The modal trend is fitted, and the main wave form is L (0,2) mode, and the relative error of the group velocity and the experimental group velocity is only 1 by the time difference method. The test results are as follows: The signal is 5 cycles, the frequency is 500 kHz, the peak-to-peak value is 200 mV, and the group velocity detection blind area of the excited L (0,2) mode wave is the probe. The arrangement spacing is less than 350 mm, and the arrangement of the ultrasonic guided wave detection probe of the carbon layer in the organic heat carrier furnace tube The best detection distance is 40 cm. The signal-to-noise ratio, time-domain and frequency-domain characteristics of the signal verify that the optimum period for detection is 5 cycles; hydrocarbon and simulated carbon-carbon layer can be added with epoxy resin and be successfully excited L (0,2) mode is encouraged. When the distance of the probe is 40 cm and the detection period is 5 cycles, the group velocity of the L (0,2) mode in the carbon tube is reduced by 7.65%, and the relationship between the velocity of the hollow tube and the carbon tube is further demonstrated to detect the organic matter. 6. Applying the principle of man-machine engineering to the evaluation of the operation risk of the organic heat carrier furnace, the weight of the man-machine environment index in the operation is 1.830, 1.293 and 1.749, and the two indexes of the access and the environment are compared with the organic heat carrier furnace. The weight of the equipment body is about 0.5. This indicates that the operation risk of the organic heat carrier furnace needs to be More attention is paid to the quality of personnel and environment management. Then, through the investigation of fire accident of organic heat carrier furnace at home and abroad, the cause of the accident is analyzed qualitatively by means of the analysis of the accident tree and the analysis of the event tree, and the cause of fire is found. The basic factors, key factors (e.g., organic heat carrier emission) 7. The flow rate of the organic heat carrier in the disk tube and the thickness of different carbon layers were simulated by FLUENT and found that the flow velocity distribution of the organic heat carrier in the disk tube was distributed when the carbon-free carbon layer was not deposited. the flow rate of the organic heat carrier on the two sides of the tube wall is slower, in particular the side of the radiant tube wall is more obvious; the flow rate of the organic heat carrier tube gradually increases from the tube wall to the center of the tube, and the radiating section is larger than the turbulent layer region on the heat-insulating side because the turbulent layer on the radiant heat side is larger than that of the turbulent layer on the heat-insulating side; near radiant tube wall, laminar flow and turbulent boundary The flow rate of the organic heat carrier medium is close to the maximum. When the flow velocity of the inlet is 1.0 m/ s, as the flow rate of the heat transfer oil decreases, the local flow of the organic heat carrier in the deteriorated and deteriorated state changes with the change of the pipe diameter and the flow rate, and the thinner the carbon layer is. The invention is beneficial to the uniform and liquid film temperature of the flow field not to be overtemperature, and finally, on the basis of the comprehensive construction of the organic heat carrier furnace product carbon detection, the safety evaluation and the FLUENT flow field simulation, a tube for the risk control of the organic heat carrier furnace is provided,
【学位授予单位】：中南大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：X933.2

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