折角入口、圆台出口和直筒型旋风分离器的性能研究

发布时间：2018-04-16 13:27

本文选题：循环流化床锅炉 + 旋风分离器　；参考：《浙江大学》2016年硕士论文

【摘要】：循环流化床锅炉技术作为一项高效、清洁的燃烧技术,在世界各国得到了广泛推广和应用。在循环流化床锅炉发展过程中,需要对其结构进行不断地改进设计。旋风分离器作为循环流化床锅炉的一个核心部件,提高其性能及与循环流化床锅炉的匹配性是研究的重要工作之一。基于循环流化床锅炉新炉型和改进结构的研发需求,本文针对改进方案中的三种旋风分离器,包括折角入口型、圆台出口型和直筒型旋风分离器,进行了冷态试验和数值模拟研究。主要研究内容及成果如下：试验研究旋风分离器的分离性能特征。搭建旋风分离器性能测试平台,试验研究基准型分离器和折角入口型、圆台出口型和直筒型三种新型分离器的分离效率和压降。结果表明：水平入口改为竖直方向上带折角的入口通道会削弱分离器分离性能,以上升和下降角度分别为45°和30°时的分离器分离性能最差；从分离效率角度来讲,研究的倒圆台排气管是对圆筒型排气管的一种有效改进方式,提高了约2%的分离效率：直筒型与筒锥型旋风分离器有相同水平的分离性能,模化试验基准工况(Vi=20 m/s,Ci=2.0 kg/m3)下,分离效率都约为96.5%,压降也都约为1100 Pa,且受运行参数和部分结构参数的影响规律也一致。模拟研究旋风分离器的气固两相流场和分离性能特征。以冷态试验装置为对象,选用RSM气相湍流模型和欧拉双流体模型对基准型和三种新型分离器进行模拟研究。在气固两相流场方面,结果表明：折角入口型、圆台出口型和直筒型旋风分离器的气固两相流场总体上与基准型旋风分离器相类似,但在局部区域存在差别。根据气固流场特点,直筒型旋风分离器从上到下可分为旋转分离区、过渡区和堆积区。在分离性能方面,结果表明：数值模拟结果和试验结果在趋势上具有较好的吻合度：折角入口通道的上升角度或下降角度的增大都不利于改善分离性能；倒圆台出口型分离器的分离性能受上、下底面直径的影响较大,正圆台型则反之；直筒型旋风分离器存在一临界本体高度,临界本体高度数值上约等于旋转分离区高度和堆积区高度之和。结合三种新型结构分离器的试验和模拟研究,权衡得到旋风分离器的优化方案。在T=800℃、dp=300 μm, Vi=30m/s、Ci=2.0kg/m3实际工况下,优化后的旋风分离器分离效率为99.17%,压降为1089 Pa,相比于实际筒锥型分离器,分离效率增加约3%,压降仅上升约200 Pa,且简化了制造工艺。
[Abstract]:As an efficient and clean combustion technology, circulating fluidized bed boiler (CFB) technology has been widely used all over the world.During the development of circulating fluidized bed boiler, it is necessary to improve its structure and design continuously.As one of the core components of circulating fluidized bed boiler, cyclone separator is one of the most important work in the study of improving its performance and matching with circulating fluidized bed boiler.Based on the research and development requirements of new furnace type and improved structure of circulating fluidized bed boiler, this paper aims at three kinds of cyclone separators in the improved scheme, including corner inlet type, round table export type and straight cylinder type cyclone separator.Cold test and numerical simulation were carried out.The main research contents and results are as follows: the separation characteristics of cyclone separator are studied experimentally.The performance test platform of cyclone separator was built and the separation efficiency and pressure drop of three new types of cyclone separator, such as standard separator and angle inlet type, round outlet type and straight cylinder type, were studied.The results show that the separation performance of the separator will be weakened when the horizontal entrance is changed to the inlet channel with a folding angle in the vertical direction, and the separation performance is the worst when the rising and falling angles are 45 掳and 30 掳, respectively, and from the angle of separation efficiency,The inverted platform exhaust pipe is an effective way to improve the cylinder exhaust pipe, and the separation efficiency is increased by about 2%. The separation performance of the straight cylinder type cyclone separator and the cylinder cone type cyclone separator has the same level as that of the cylinder type cyclone separator. Under the standard condition of the model test, there is 20 m 路s / s ~ (-1) C ~ (2. 0) kg 路m ~ (3).The separation efficiency is about 96. 5, and the pressure drop is about 1100 Pa. the effect of operation parameters and some structural parameters is consistent.The characteristics of gas-solid two-phase flow field and separation performance of cyclone separator are simulated.RSM gas phase turbulence model and Euler double fluid model were used to simulate the datum and three new separators.In the aspect of gas-solid two-phase flow field, the results show that the gas-solid two-phase flow field of the angle inlet type, the circular outlet cyclone separator and the straight cylinder cyclone separator is similar to that of the reference cyclone separator on the whole, but there is a difference in the local area.According to the characteristics of gas-solid flow field, the straight cylinder cyclone separator can be divided into rotating separation area, transition zone and accumulation area from top to bottom.In terms of separation performance, the results show that the numerical simulation results are in good agreement with the experimental results in the trend: the increase of the rising angle or the descending angle of the entrance channel is not conducive to improving the separation performance;The separation performance of the inverted cylinder type separator is affected by the diameter of the bottom surface of the upper, and the positive cylinder type of the cyclone separator has a critical body height, the vertical cylinder type cyclone separator has a critical mass height, and the vertical cylinder type cyclone separator has a critical mass height.The critical bulk height is approximately equal to the sum of the height of the rotating separation region and the height of the stacking region.Combined with the experimental and simulation studies of three new types of structural separators, the optimal scheme of cyclone separators was obtained.The optimized cyclone separator has a separation efficiency of 99.17 and a pressure drop of 1089 Pa. compared with the actual cone separator, the separation efficiency is increased by about 3 times, and the pressure drop is only increased by about 200Pa. the optimized cyclone separator has a separation efficiency of 99.17 and a pressure drop of only about 200 Pa. compared with the actual cone separator, the separation efficiency is 300 渭 m, and the pressure drop is only about 200 Pa. under the actual operating conditions, the optimized cyclone separator has a separation efficiency of 99.17 and a pressure drop of 1089 Pa.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK229.66

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