Analysis And Optimal Control Of Gas Calorific Value

As China has listed high-energy-consuming industries as key renovation projects in recent years,with particular emphasis on industrial energy conservation and consumption reduction,the steel industry is the focus in the industrial sector.Blast furnace ironmaking is the most energyintensive in the industry,and it is also the most polluted.The blast furnace hot blast stove is a device that plays an important role in the energy consumption and pollution of the blast furnace.At present,most of the working conditions of the hot blast stove in China are fixed air-fuel ratio combustion,but in the case of gas fluctuations,the fixed The air-fuel ratio combustion state will continuously lead to intermittent occurrence of peroxidic combustion and insufficient combustion,which may cause the combustion efficiency of the hot blast stove to be low and the blast furnace production state to be poor.Therefore,in order to achieve rational production,effective use of gas energy,reduce energy consumption,reduce pollution emissions,timely and accurate control of air-fuel ratio and detection of gas calorific value is of great significance to the entire production process.In order to solve the above problems,this paper designs a fixed-residue oxy-combustion calorimeter as a feedforward system for working in a hot blast stove,allowing gas and air to enter a fixed-gas combustion calorific value meter,gas and air before being sent to the hot blast stove.After the flow and pressure are tested,it is passed into the combustion chamber of the calorimeter to make residual oxygen combustion.During the combustion process,the residual oxygen content and temperature of the flue and the CO content are optimized to optimize the overall combustion air-fuel ratio,and the optimized air-fuel ratio will be optimized.The ratio is applied to the hot blast stove during the working process.For the above gas calorific value workflow,this paper has done the following detailed work and solutions:Improve the gas calorimeter control platform: further improve the gas calorimeter air regulator valve,replace the original air regulator valve,and replace the original PID control strategy with a fuzzy PI control strategy to replace the original air regulator valve The new control valve that responds faster(the adjustment that was completed in 2 minutes now becomes 30 seconds);the PID control air conditioning valve is used to update the original control method after expert experience and field test.In order to blur the PI control,the air control valve has better control effect,reduces the start reaction time,and improves the situation that the excess gas is taken away by the air and the air-fuel ratio is not balanced,causing the ignition failure.On the basis of improving the air regulating valve,the MCGS configuration display screen is further improved to increase the function of the flue CO content display,the gas calorific value prediction display,and the previous data transmission and finishing functions are improved and upgraded.The modified gas calorimeter is subjected to constant residual oxygen combustion,and the residual oxygen range is controlled between 1% and 2%,and the gas calorimeter is monitored by field monitoring data,and each time is collected by the zirconia detector.The residual oxygen content,the residual oxygen content at each moment and the various gas calorific values after the test are compared to find out whether there is correlation between the residual oxygen content and the gas calorific value,and then the collected data is subjected to in-depth data mining.Look for a linear relationship between data(air flow,gas flow,air pressure,gas pressure,residual oxygen content)and the gas value of the dependent variable.In the case of correlation between residual oxygen content and gas calorific value,in order to verify whether known data(air flow,gas flow,air pressure,gas pressure,residual oxygen content)can be utilized,establishing an RBF neural network model is difficult to detect.The calorific value is predicted online.After the gas calorimeter is improved and the gas calorific value data is collected and analyzed,the air and gas volume entering the hot blast stove are prepared in advance,so that the air sent to the hot blast stove is affected by the pressure fluctuation.The imbalance of gas ratio leads to effective improvement of combustion efficiency and low production efficiency.It can adjust the air-fuel ratio mismatch unevenness caused by changing air and gas at any time,and make preliminary prediction on the gas heat value at the site.The visual effect thus assists in adjusting the air-fuel ratio of the hot blast stove.