Coal Quality On-line Identification Based On Multi-sign Combination Judgement Method

With the improvement of people’s awareness of environmental protection and the guiding role of national policies,the requirements for reducing the emission of pollutants in thermal power plants are also becoming more and more stringent.On the basis of ensuring a stable and reliable power source for the development of human society,a large number of power science workers have made great efforts to reduce the emission of pollutants from power plants.One of the methods is to further improve the operating efficiency of power plants boilers,and coal quality plays an important role in the economic operation of boilers.Real-time monitoring of the coal into the furnace,enabling the operators to timely adjust the boiler combustion.However,due to technical or financial problems,the majority of power plant boilers are still dependent on offline testing of coal quality information.Based on the innovation concept of coal quality database established by predecessors,this paper uses the positive and negative balance verification method of boiler efficiency to identify the incoming coal quality online and verify its accuracy.The maximum difference of calorific value can basically meet the industrial demand.In order to further improve the accuracy of the monitoring results,set a reasonable calorific value for the expansion conditions,get a number of coal into the furnace for analysis.The coal mill is taken as the research object,the energy balance equation is established,and the received water content of the coal entering the furnace is obtained by solving the equation.The practical application results show that the error of the moisture monitoring data is within the allowable range;Fully tap the information of coal contained in the flue gas composition to establish a soft measurement model about the coal brought into the furnace,with the coal mill module obtained moisture data and on-line measurements of the relevant data can also make the identification of the coal into the furnace into realization,low quality coal heat monitoring results of the error slightly higher than the former.Similarly,the type of the coal to be identified is appropriately expanded based on the coal quality database.Taking the intersection of the above two coal quality data sets and obtaining several kinds of coal quality data,combining with the actual situation,it establishes the fuzzy comprehensive evaluation model,and then can obtain the coal which is closet to the actual coal quality for the operator timely according to the quality of coal adjust the boiler operation.The actual operation results show that the absolute error rates can be effectively corrected for the three cases of“close”,“greater than”,”less than”.Obviously,the model can not only ensure that the errors will not be enlarged,but also improve the identification accuracy of coal entering effectively,which is of great significance for the combustion regulation of the boiler.With the aid and breakthrough of the traditional method of coal quality identification,the coal quality components obtained from positive and negative balance check,coal mill and flue gas components are taken as indications.Combined with the fuzzy comprehensive evaluation model,the final identification of coal quality is realized,the accuracy of online identification of coal into the furnace is further improved,and the above modules are integrated into a software package,with high practical value.