The temperature of the flue gas (exhaust gas) discharged from the glass melting furnace is very high, generally around 1400-1500 °C. The exhaust gas contains a large amount of heat energy, which is of great significance to the utilization of waste heat in glass-melting furnaces.
The regenerator in the glass melting furnace is a waste heat recovery device—a part of the exhaust gas waste heat utilization system.
It uses refractory material as a heat accumulator (called checker brick) and accumulates a part of the heat discharged from the kiln to heat the air entering the kiln. When the high-temperature waste gas in the kiln flows through the regenerator lattice body, the checker bricks are heated, and the temperature of the checker bricks gradually increases during this process. The heat stored in the grid will heat the gas or air flowing through the checker brick after the flame turns, to ensure that the flame has a high enough temperature to meet the needs of glass melting. During this process, the temperature of the checker brick gradually increases. Lower, and so on.
Therefore, the function of the regenerator is to absorb the heat contained in the exhaust gas through the absorption and heat storage of the checker bricks and then pass it to the air and gas to heat it to a certain temperature, to save fuel and reduce costs.
3-wind and fire partition wall;
6-hot repair door;
7-furnace bar door;
The structure of the vertical regenerator commonly used in glass-melting furnaces is shown in the figure. The lower part is the air and gas flue. The partition wall between the regenerators is called the wind-fire partition wall. Due to the high temperature on the upper part and the corrosion of flying materials, it is easy to cause fire penetration after burning, so its thickness is generally large, and it requires tight masonry. To reduce the heat loss of the outer wall of the regenerator, insulation bricks are generally built. Since the regenerator often needs to repair checker bricks and remove dust, hot repair doors, and cleaning holes are left on the outer wall, and ash pits must be left inside the flue.
The form of the regenerator
Improve the heat storage performance and service life of the regenerator, there are many forms of regenerators at home and abroad, but as far as domestic float glass melting furnaces are concerned, the most common ones are connected structures, separated structures, semi-separated structures, Two small furnaces connected structure, two-stage structure, fully connected structure and so on.
Requirements for Regenerator Performance
1. Ensure that the air and gas have a certain preheating temperature, and the preheating temperature should be stable;
2. Could make full use of the exhaust gas heat;
3. The airflow should be evenly distributed on the cross-section of the regenerator, and the airflow resistance should be small;
4. The structure is simple, compact, and firm, which is convenient for inspection, cleaning, and hot repair.
The heating effect of the regenerator on the gas is intermittent, but the production of the tank kiln is continuous. Therefore, there must be two sets of equipment that work in rotation. Therefore, the regenerators are always used in pairs, and the small furnaces matched with the regenerators are also in pairs.
The function of heat storage device
1. The heat storage device is a combustion-supporting and heat-supporting device, which can preheat the air (and gas fuel with low calorific value), which is beneficial to combustion, can increase the combustion temperature of the fuel and plays a combustion-supporting role.
The fuel with a low calorific value can be burned at a high temperature to produce the combustion effect of fuel with a high calorific value, and the fuel with a high calorific value can be burned at a higher temperature to generate more heat and play a heating role.
2. The combustion-supporting and heat-supporting functions of the regenerator are necessary conditions for the production of high-grade high-quality glass.
The melting speed and melting quality of glass batch materials require high temperatures. For low calorific value fuels (such as producer gas), the temperature at which the batch material can be melted into a qualified glass liquid can be reached by double preheating the combustion air and fuel gas. For fuels with high calorific value (such as heavy oil, natural gas, etc.), only preheating the combustion air can achieve a higher combustion temperature, which is a necessary condition for the production of high-grade and high-quality glass. It can be said that if the glass melting furnace is not equipped with a regenerator, even if fuel with high calorific value is used, it will be difficult to produce high-grade high-quality glass.
3. The heat storage device is an energy-saving and environmentally friendly device that can recover the waste heat of the flue gas and reduce the temperature of the exhaust gas, thereby reducing the fuel consumption of the furnace and saving energy.
For furnaces using high-calorific-value fuels, 30% to 40% of fuel can be saved; the amount of fuel is reduced, and the amount of combustion exhaust gas can naturally be reduced, while nitrogen oxides, sulfur and its oxides, and flue gas in the flue gas The emission of dust and other harmful substances is also reduced accordingly, which has a more obvious effect on environmental protection. For glass melting furnaces using low calorific value fuels, energy saving and emission reduction can be achieved through double preheating of combustion-supporting air and fuel gas.