高碱煤燃烧过程中碱金属沾污特性的预测模型研究

Study on prediction model of alkali metal contamination characteristics during high alkali coal combustion

为了克服传统预测方法的局限性,笔者提供了一种能够准确预测高碱煤燃烧沾污特性的模型,该预测模型还可以根据煤的沾污特性给出其适用的温度范围。本预测模型采用三步化学萃取法来检测煤样中的钠含量,以避免对煤进行灰化时造成钠的挥发损失,因此能够直接精确地测定煤样中的总钠含量及各个形态的钠含量。另外,本预测模型不仅考虑钠、钾和固相沾污源的影响,同时考虑到其它易挥发组分(如碱土金属、硫和氯)对煤沾污特性的影响,并将温度引入沾污模型中。按本模型获得的沾污指数R_T预测量化区间如下:R_T≤0.60,弱沾污性;0.60<R_T≤1.00,中等沾污性;R_T>1.00,强沾污性。为验证该预测模型的准确性,分别以沙尔湖煤和神华准东煤为试验对象对预测模型进行了验证,验证结果表明:①700℃时,R_T=0.59<0.60,沙尔湖煤处于弱沾污区;850℃时,0.60<R_T=0.83<1.0,沙尔湖煤处于中等沾污区;900℃时,0.60<R_T=0.95<1.0,沙尔湖煤处于中等沾污区;950℃时,R_T=1.11>1.0,沙尔湖煤处于强沾污区。②神华准东煤相比于沙尔湖煤沾污性较弱。850℃时,R_T=0.53<0.60,神华准东煤处于弱沾污区;900℃时,0.60<R_T=0.78<1.0,神华准东煤处于中等沾污区;950℃时,0.60<R_T=0.87<1.0,神华准东煤处于中等沾污区。该预测结果分别与沙尔湖煤和神华准东煤的燃烧试验结果一致,进一步验证了预测模型应用的准确性与可靠性,可适用于高碱煤工业应用过程中碱金属沾污性的预测。

In recent years,with the increasing level of mechanization,automation and intelligence in mining,dust pollution in the working environment is becoming more and more serious.In order to further improve the clean production level of coal mines,promote the safety guarantee ability and occupational health level of coal mines,this paper analyzes the research status of dust control in China,summarizes the achievements of dust control theory and technology in the past 20 years,and puts forward the future development direction.In this paper,the existing basic theories of dust control are expounded,including dust dispersion pollution law,dust micro wetting theory,dust condensation and wet dedusting theory,wet shotcrete dedusting theory.Based on the above theory,domestic universities and scientific research institutes have developed dust control and dedusting technology of different dust sources,such as local atomization closure and air curtain isolation of comprehensive mining face,wind fog double curtain synergistic effect of comprehensive mining face,coal seam water injection strong infiltration and moistening,mine wet(tide)spray operation system,high-efficiency environmental protection dust suppressor,etc.At the same time,in view of the shortcomings of the existing research,the next research prospects are given in four aspects:intelligent dust prevention,coal seam water injection dust reduction,mining environment dust reduction,dust suppression materials.Research and practice show that China’s coal mines have initially formed a theoretical and technical system of dust prevention and control.In the future,it is necessary to take intelligent dust prevention as a starting point,realize high-precision dust sensing transmission evaluation and early warning,and develop a combined dust remover integrating atomization,dry-type,dry wet mixed type,miniaturization and large air suction,At the same time,the technology and equipment system of high-efficiency ventilation and dust control of fine dust in wide area complex space such as comprehensive mining face and comprehensive mining face are realized.At the same time,the technology and equipment system of hydraulic strong permeability and moistening technology in low permeability coal seam of mine,intelligent shotcrete dust-proof robot and dust suppression material are also achieved.In this way,the mine dust can be effectively controlled by different sources,and the cleaner production level of the mine can be improved.