呼吸性煤尘表面异质核化凝结效果预测及降尘试验

Prediction of heterogeneous nucleation condensation effect on the surface of respiratory coal dust and test of dust reduction test

  • 摘要: 煤尘颗粒表面润湿性是制约湿式除尘效率的重要因素,煤尘颗粒表面异质核化凝结是一种无任何污染、无需考虑颗粒表面润湿性,且能有效提升煤尘颗粒被液滴捕捉效率的方法,而人为干涉温湿度环境变化是激发煤尘颗粒表面核化凝结效应的必要条件。为获得不同干涉条件对矿井呼吸性煤尘颗粒核化凝结效果的影响,基于颗粒核化凝结试验系统,围绕煤尘初始温度、干涉气体相对湿度、干涉气体凝结温差3个因素开展单因素分析和多因素正交试验。结合使用均方差赋权法、非线性回归分析法、预测效果评价指标,确定各影响因素在煤尘颗粒核化凝结效果中的权重占比,构建颗粒核化凝结多元非线性回归预测模型,且评价模型预测的准确性。搭建颗粒核化凝结与喷雾协同降尘试验系统,对比分析了二者协同与单一降尘方式对呼吸性煤尘的治理效果。结果表明:干涉气体相对湿度对核化凝结效果影响最大,二者呈正相关性,且当干涉气体相对湿度大于70%时才能激发明显的核化凝结效应;干涉气体凝结温差对核化凝结效果的影响仅次于干涉气体相对湿度,凝结效果会随着温差的增大呈先下降后上升趋势;煤尘初始温度影响权重最小,且对于煤尘颗粒粒径≤1 μm和> 2 μm的颗粒群分别呈现正向和反向激励;基于多种方法结合构建的多元非线性回归模型的预测准确性较优,误差小,可用于量化表征一定范围内温湿度干涉条件下的矿井呼吸性煤尘颗粒核化凝结效果;利用颗粒核化凝结与喷雾协同降尘可以有效解决煤尘表面润湿性差的问题,相较于纯水喷雾的降尘效率提升了131.84%。

     

    Abstract: Surface wettability of coal dust particles is an important factor restricting the efficiency of wet dust removal. Heterogeneous nucleation condensation on the surface of coal dust particles is a means without any pollution, without considering the surface wettability of particles, and can effectively improve the efficiency of coal dust particles being captured by droplets. Human interference with the change of temperature and humidity environment is a necessary condition to stimulate the surface nucleation condensation effect of coal dust particles. In order to obtain a quantitative prediction mathematical model for the influence of temperature and humidity conditions on the condensation effect of mine respiratory coal dust particles, based on the visualization experiment platform of particle condensation, single factor and multi-factor orthogonal experiments were carried out around three factors: initial temperature of coal dust particles, relative humidity of hot and humid gas, and temperature difference of condensation temperature. Combined with mean square error weighting method, nonlinear regression analysis method and prediction effect evaluation index, the weight proportion of each influencing factor in the condensation effect of coal dust particles was determined. Based on this, a multivariate nonlinear regression prediction model for particle condensation was constructed, and the accuracy of the model prediction was evaluated. Based on the experimental system of particle nucleation condensation and spray synergetic dust suppression, the control effects of the two synergetic and single dust suppression methods on respirable coal dust were compared and analyzed. The results show that the relative humidity of hot and humid gas has the greatest influence on the nucleation condensation effect, and the two are positively correlated, and the obvious nucleation condensation effect can be activated only when the relative humidity is greater than 70%. The influence of temperature difference on condensation effect was second only to gas relative humidity, and the condensation effect decreased first and then increased with the increase of temperature difference. The influence weight of the initial temperature of coal dust particles is the least, and the particle groups with particle size ≤ 1 μm and > 2 μm are stimulated positively and reversely, respectively. The multivariate nonlinear regression model based on the combination of various methods has better prediction accuracy and small error, and can be used to quantify the condensation effect of coal dust particles nucleation under the condition of temperature and humidity interference in a certain range. The problem of poor surface wettability of coal dust can be effectively solved by using particle nucleation condensation and spray, and the dust removal efficiency is increased by 131.84% compared with pure water spray.

     

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