| With the rapid growth of China's economy,China's power industry has also entered a rapid development stage.In 2015,China's thermal power installed capacity exceeded 900 million kilowatts,and the total amount of thermal power generation accounted for about 80% of the total power generation in China.The annual consumption of coal fired up to 20 million tons.It is expected to reach 950 million k W by 2020,of which coal electricity is 650 million k W,accounting for 68.4%.The acid dew point measurement of flue gas of thermal power unit and low temperature corrosion of the low temperature heating surface of the boiler have aroused wide attention.The accurate estimation and measurement of the acid dew point of the flue gas can not only reduce the cost of the design and manufacture of the boiler,but also greatly reduce the operation cost of the power station.Therefore,the estimation and measurement of the acid dew point of the flue gas has an important influence on the safe and economical operation of the boiler.Based on the theoretical estimation of flue gas acid dew point and the experimental study of the basic components in fly ash and the dew point of acid,we have explored the influence of flue gas dew point estimation on the design process of boiler and the influence of some components in flue gas on the dew point temperature in two ways.First,the acid dew point value is estimated by using the existing data and the acid dew point estimation formula.Secondly,the acid dew point measurement test bed was set up to measure the acid dew point value under different working conditions.Finally,the empirical correlation of the fly ash coefficient is obtained by using the experimental data.The main contents are as follows:The existing estimation formula of flue gas acid dew point is programmed,and the acid dew point under various working conditions is calculated by using component analysis data of commonly used coal species in China.Through the analysis and comparison of the calculation results,the advantages and disadvantages of various acid dew point estimation formulas are evaluated.In order to study the factors affecting acid dew point and the degree of influence,a test bed of acid dew point measurement was set up.By simulating the flue gas environment on the heating surface of the boiler,the influence of flue gas volume,sulfuric acid concentration,the percentage of calcium oxide and Magnesium Oxide on the dew point and the degree of influence were studied.The experimental results show that in reverse direction change of acid dew point temperature and the amount of flue gas;the higher the concentration of sulfuric acid vapor in the flue gas acid dew point of flue gas is higher;the percent content of fly ash calcium oxide in the acid dew point temperature is low;fly ash in Magnesium Oxide higher content of acid dew point temperature is lower.The effect of Magnesium Oxide on acid dew point is stronger than calcium oxide.This paper also modifies the fly ash coefficient in the empirical formula for the calculation standard of the former Soviet thermal unit.It is known that the fly ash coefficient is an experimental variable and is related to the main component s in the fly ash through the previous experiments and the related literature.Based on the statistics and arrangement of experimental data and fly ash composition data,the empirical correlation between fly ash coefficient and the percentage of calcium oxide in fly ash and percentage of Magnesium Oxide in fly ash is established by least square method: 0.8917 WCa O+ 0.5065 WMg O+ 0.5888.The correlation of the experimental data is close to the original data,and the error is small,and it can reflect the relationship between the fly ash coefficient and the content of calcium oxide in fly ash and the content of Magnesium Oxide. |
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