The high melting temperature of the glass melting furnace, the sensitivity of the kiln body size to temperature changes and the thermal expansion of the kiln refractory materials all require that special attention should be paid to the temperature rise of the glass melting furnace from the ambient temperature to the melting temperature. Interaction of speed and temperature.
(1) Preparation work
Preparations should include the following:
① Check whether all tie rods, fasteners, expansion joints, thermocouples, etc. of the melting furnace meet the requirements;
② Temporarily close the openings of the melting furnace, such as the feeding hole, observation hole, nozzle brick hole and the flue on the feeding channel
③ Check the reversing ram system to ensure that the air inlet end is sealed and the air outlet is closed;
④ Check the counterweight of the flue gate;
⑤ Check all heating combustion equipment, such as combustion system, oil, gas, nozzles and various tools;
⑥ Check whether the temperature rise test instrument and the indicator on the top are complete;
⑦Heat the main flue and chimney before ignition.
(2) heating up
The heating up process of the melting kiln is very demanding. In addition to controlling the thermal expansion of the refractory material to ensure that the gap between the entire kiln body and the steel structure is properly matched, attention must also be paid to the expansion caused by the crystal state change of the refractory material itself. Phenomenon. When the temperature is 100~650C, the expansion of silica bricks is extremely violent, the expansion of magnesia bricks is the most violent when the temperature is above 1000 °C, and the expansion of fused-cast zirconium corundum bricks is flat when the temperature is above 800 °C. Therefore, if the temperature rise is not properly controlled, it will cause cracks in the kiln body, which will affect the service life of the furnace and the refractory itself. Therefore, the heating of the kiln must be carried out in strict accordance with the regulations.
① Establish a strict heating system.
②Adjust the flue damper to 25mm from the bottom, add combustion-supporting air to each small furnace, and keep the inside of the kiln
Positive pressure.
③Open the cooling water pipe of the liquid flow hole to circulate the cooling water to work
④ The reversing system shall be exchanged every 20~30 minutes.
⑤ Check the expansion of the refractory once an hour (adjust the fasteners twice an hour between 150 and 700 ℃), and make a record of the expansion.
⑥ Loosen the bolts of the steel structure everywhere in time.
The above steps are the traditional kiln baking method, and the kiln baking takes a long time.
(3) rapid heating
In order to make the newly-built melting kiln put into production as soon as possible to generate benefits, measures should be taken to shorten the kiln baking time of the melting kiln. Rapid heating is also called fast baking kiln. It mainly uses hot air to prevent open flame from directly entering the kiln, so it can also be called hot air baking kiln. The kiln time of the traditional method is as long as 14~20 days, but it can be shortened to 9~13 days by using the hot air kiln, and the time is reduced by 35%.
The working principle of the hot-air kiln is to use the flue gas produced after the gas is fully burned in the combustion chamber of the hot-air kiln to mix with a large amount of excess air. Under slight positive pressure, it is evenly heated by the combustion products. The main equipment used in the hot air baking kiln includes spray guns, blowers, kiln ovens, and attached control systems and temperature detection instruments. There are two ways to operate the hot air kiln. The first method is relay baking from the bottom of the regenerator upwards. Before firing the kiln, put down the chimney gate, and start to ignite the spray guns from the main flue. When the temperature in the kiln rises to the required value, the rest of the spray guns need to be ignited successively from the bottom of the regenerator and the small furnace neck. The flow of hot air in the heat storage chamber can be regulated by branch flues. The second method is to start baking from the headspace of the furnace. This method requires special hot-blast kiln equipment, and its quantity and installation location vary with the type, size and heating system of the furnace. At the beginning, the dampers in front of the chimney and the inlet of the regenerator must be closed. The temperature in the upper space of the melting furnace is higher, and the temperature at the bottom of the regenerator is lower. With the increase of the volume capacity of the hot air, the pressure in the upper part of the melting furnace rises above 14.7Pa. The ram at the entrance of the hot chamber to maintain the kiln pressure at 8Pa. When the temperature in the upper space of the melting furnace reaches 600°C, start to ignite the auxiliary spray gun on the top of the lattice body, and start the reversing system at the same time, reversing once every 5 to 10 minutes, and then gradually extend until the furnace is amplified, the exchange is normal, and the heat storage The room temperature gradually adapts to the working conditions.
During the hot air baking kiln, first of all, it should be noted that all parts of the furnace should be closely monitored throughout the process, and measures should be taken in time. Secondly, the chimney must have the necessary draft force before heating up the kiln. Finally, in order to meet the needs of the fast baking kiln, corresponding measures must be taken in the design of the thermal insulation and structure of the melting inspection.