数字全息在线测量煤粉粒度分布

On-line measurement of coal powder size distribution using digital holography

煤粉粒度是燃煤电厂的重要指标,在线测量煤粉粒度能够即时指导锅炉优化运行,对节能减排具有重要意义。搭建了一套模拟一次风粉管道的煤粉粒径在线测量的装置,解决了传统取样方法堵塞和测量实时性差的问题,并设计实验研究数字全息在线测量煤粉粒度的可行性和可靠性。实验结果表明,数字全息在线测量煤粉粒度分布曲线与激光粒度仪的测量曲线趋势一致,平均粒径相对误差为5.6%,表征粒度分布的关键参数d50和d90的相对误差均低于2%,满足工业应用的需求。数字全息技术对稀释前后不同浓度的煤粉粒径关键参数的测量相对误差均低于7%,稀释前后的煤粉粒度的数量分布和体积曲线的趋势一致,验证了数字全息技术在线测量煤粉粒度分布的可靠性,为整体测量装置的开发奠定了基础。

Particle size distribution of coal powder is one of the most important indexes which contribute a lot to energy conservation and emission reduction of power plant. Digital holography is applied to measure the particle size distribution on a set of device stimulating the actual working conditions of coal supply system of power station. The results show that the distribution curve measured by digital holography has the similar trend with the curve measured by laser particle size analyzer. The relative error between the average diameters is 5.6%. The relative errors between the d50 and d90, are less than 2% which is in the allowable range. The relative errors between before and after the dilution is lower than 7%. The trends of particle size distribution curve of the same sample are consistent in different conditions. The reliability of digital holography for on-line measurement of pulverized coal particle size distribution is verified, which lays a foundation for the development of the overall measurement instrument.