针对目前工业现场常采用的多级过滤伴热抽取预处理方式存在样气失真、管线易堵塞和腐蚀、测量延时、维护量大等问题,开展烟气恒流稀释预处理技术研发并将其应用于复杂工业现场.研究首先基于渐缩喷嘴的恒流特性开展验证实验,实验结果表明,渐缩喷嘴入口流量与喷嘴喉径呈正相关而与背压呈负相关性,当背压低于 45 kPa时气体达到声速壅塞状态且保持恒流;随后基于原理实验研制适用于不同复杂工业环境下的高保真烟气恒流稀释预处理装置,并结合可调谐二极管激光吸收光谱(TDLAS)技术开发气体在线监测分析系统,同时将其应用于煤粉锅炉水冷壁近壁面气氛和磨煤机出口 CO 在线监测现场,实现了高尘、高湿、高腐蚀等恶劣工况下烟气高保真取样和高精度测量,有效解决了目前复杂工业现场烟气取样管线堵塞、气体成分失真等问题,为气体高精度在线监测系统安全稳定运行提供技术支撑.
Study on Constant Flow Dilution Pretreatment Technology of Flue Gas and Its Application in Complex Industrial Conditions
At present,the multi-stage filtering heat tracing extraction pretreatment method commonly used in industrial field has many problems,such as sample gas distortion,pipeline blockage and corrosion,measurement delay,large maintenance,etc.In this paper,the research of flue gas constant flow dilution pretreatment technology was carried out and this technology was applied to complex industrial sites.Firstly,the verification experiment was carried out based on the constant flow characteristics of the tapered nozzle.The experimental results showed that the inlet flow rate of the tapered nozzle is positively correlated with the throat diameter of the nozzle and negatively correlated with the back pressure.When the back pressure is lower than 45 kPa,the gas reached the sound velocity choking state and maintains constant flow.Subsequently,based on this prototype experiment,a high fidelity flue gas constant flow dilution pretreatment device suitable for different complex working conditions was developed.Then,combined with the gas monitoring analyzer based on tunable diode laser absorption spectroscopy(TDLAS)technology,the high fidelity flue gas constant flow dilution pretreatment device was applied to CO monitoring at the atmosphere field near the water wall of coal-fired unit boiler and the outlet of coal mill.The high fidelity sampling of flue gas under high dust,high humidity and high corrosion conditions were realized.And the problems of sampling blockage and sample gas distortion in complex industrial sites were solved.Eventually,it can provide technical supports for the safe and stable operation of the online gas monitoring system.
constant current dilutiontapered nozzlesound velocity chokinghigh fidelity samplinggas measurement
万方数据
维普
