Ignition Location And Ignition Facilities Of Tunnel Roasting Kiln

December 20 18:26 2021

1. The principle of choosing the ignition position

(1) Determine the ignition position according to the changes in the materials used in the masonry kiln and kiln roof during the heating process.

(2) Select the ignition position according to the heating requirements of the brick-making materials, so that when the brick is raised to the firing temperature, it is just in the firing zone.In short, the exact ignition position should be determined according to the chemical composition and physical properties of the materials of the masonry kiln and the raw materials for making bricks, as well as the requirements for the heating rate. Generally, the ignition position of the tunnel roasting kiln should be located at the rear of the preheating zone or between the preheating zone and the roasting zone.

2. Masonry of fire box car for ignition The fire box car is located at the ignition position of the tunnel roasting kiln. It is used for putting into production and preheating and heating up the kiln, as well as igniting the front car body brick. The firebox car is an empty kiln car. A front wall with a thickness of 370mm is built with standard bricks on its countertop. The wall is equipped with coal filling holes, observation holes and dust removal holes. Behind the front wall is the fire box combustion chamber. Behind the combustion chamber is a rear wall with a thickness of 370mm and a height of 500mm. The front and rear walls are equipped with inclined grate bars. Brick walls with a thickness of 240mm are built on both sides of the fire box to prevent coal and ash from entering the bottom of the kiln car from both sides of the kiln car.The brick wall of the fire box car should be separated from the kiln wall and the kiln roof by a gap of 60mm to prevent the wall from expanding and touching the kiln wall and the kiln roof after ignition. When in use, the gap can be blocked with refractory fiber felt.

Three, the setting of the combustion space The combustion space is a certain space reserved between the fire box car and the first vehicle when the tunnel roasting kiln is ignited, as the space where the fuel combustion flame and high temperature hot air flow in the fire box car can be evenly distributed on the section of the billet stack Location. The length of the combustion space is generally 0.5 to 1.5 parking spaces, with a maximum of two parking spaces. The combustion space is filled with empty kiln cars.

Fourth, the stacking method of the drawing car At the back of the combustion space, there are generally 2 to 3 dedicated pallet trucks. The function of the fire truck is to better distribute the flame and high-temperature hot air from the fire box truck to the cross-sections in the kiln, so that the bricks of the subsequent trucks can be uniformly heated.The blank stacking method and the principle of the blanking car are the same as the normal production stacking method, except that the stacking method is as thin as possible, that is, the ventilation holes are as large as possible, so that the high-temperature hot air can flow backward through the blanking car. Heating other blank cars. At the same time, the code method of “top density and bottom sparse, side dense and medium sparse” is adopted to make the high-temperature air flow more evenly distributed on the top, middle and bottom of the blank. In addition, pay attention to the gap between the top of the billet stack and the top of the kiln, and the gap between the two sides of the billet stack and the kiln wall as small as possible to prevent a large amount of airflow from flowing away from the top and side parts. It should also be noted that the green body should be slowly heated and dried to prevent the rapid heating of the green body from bursting and collapsing, affecting the air flow.

5. Dry bricks in the tunnel roasting kiln From the fire box car at the ignition position to the entrance end of the tunnel roasting kiln, except for 2 to 3 fire-bearing cars, the others are blank cars that are normally produced. In the project that was just completed and put into production, the bricks in the tunnel kiln did not have a normal heat source for drying, so the moisture content of the bricks entering the tunnel roasting kiln was greater than 6%. The bricks with higher moisture content can be put into production and ignited after entering the tunnel roasting kiln. The heat source of the fire box car is used to gradually preheat and heat up and dry in the tunnel roasting kiln.

6. Stacking of fuel and furnace ash for fire tank cars There should be two empty kiln cars behind the firebox cars for stacking fuel for the firebox cars and the ash taken out from under the firebox cars; multiple empty kiln cars can also be parked continuously. The number of empty kiln cars depends on how convenient it is to transport fuel and leave the ash.Seven, ignition procedure

(1) Turn on the ventilation equipment When igniting, the smoke exhauster should be turned on first, so that negative pressure is formed in the kiln. Before turning on the smoke exhauster, ignite the fire to prevent the fire box car from running out and burning the operator.

(2) Ignite flammable fuel Use a small amount of diesel oil and cotton yarn to ignite the wood in the fire box combustion chamber. Be careful to add less firewood to prevent the fire from being too fierce. After a period of low firewood heating, coal is added to burn.

(3) Adjust the air volume in time Adjust the air volume of the smoke exhauster and the air intake gate of the fire box car in time to ensure that there is a certain amount of air flow in the combustion chamber of the fire box car to support combustion.

8. Operation adjustment of the firebox car after ignition

(1) Increase the air volume at the right time Gradually increase the air volume in a timely manner, accelerate the combustion, and increase the temperature of the firebox car.

(2) Adjust the pressure in the fire box car When igniting, the interior of the fire box is in a low temperature. As the temperature gradually rises, the gas expansion will cause the pressure to increase, and positive pressure may appear. For this reason, it is necessary to adjust the suction force of the smoke exhauster in time to maintain the negative pressure in the firebox vehicle.

(3) Increase the amount of smoke discharged in due course As the temperature inside the firebox increases and the combustion intensity increases, a large amount of air is required. Therefore, it is necessary to increase the air volume of the smoke exhauster in a timely manner and open the gate valve on the large smoke exhaust pipe.

(4) Properly control the amount of fuel The amount of fuel in the fire tank must be properly controlled.

The fuel should be added evenly to ensure the normal heating of the kiln.IX. Precautions for kiln ignition

(1) Choose an appropriate heating rate The kiln can be divided into two times. The first is to be carried out before the ignition is put into production. The main purpose is to drain the construction water and natural moisture of the kiln body and the kiln roof as much as possible to prepare for the ignition and production. The second is to control the heating rate during ignition and commissioning. This is not only to better remove the moisture of the kiln body, but more importantly, to conduct heat treatment according to the physical and chemical properties of the kiln body material. Special attention should be paid to the heat-resistant concrete roof adjustment board, which is made of aluminum silicate cement and refractory aggregates of different particle sizes. Its production and use quality determine the service life of the kiln. As far as the heating of the kiln is concerned, the strength of the refractory concrete ceiling board decreases significantly when it is heated to 100~400℃, and its strength continues to decrease when it is heated to 1000~1100℃. Only when heating to 1300°C is continued, the strength of the refractory concrete ceiling slab is significantly increased due to the partial sintering of the refractory concrete ceiling. However, the use temperature of refractory concrete ceiling slab in the tunnel kiln roasting kiln of coal gangue sintered bricks cannot reach the sintering temperature required by itself. Therefore, the use of refractory concrete ceiling slabs should be reasonable, especially during the kiln drying and ignition and commissioning stages. Heating system. It should be known that the greater the amount of aluminum silicate cement used in the refractory concrete ceiling board, the greater the sensitivity to unreasonable heating systems and the greater the impact on its strength when the kiln is ignited and put into production.From a theoretical point of view, after prefabrication, refractory concrete ceiling panels should be subjected to special thermal treatment, so that they can be finally sintered under a reasonable heating process system to achieve higher strength and improve performance. However, in actual construction, we cannot do this. When the kiln is ignited and put into production, it is quite difficult to achieve a reasonable temperature rise of the refractory concrete ceiling slab of the tunnel roasting kiln. We can only try to solve it seriously in operation after understanding the performance of the slab.

(2) Choice of ventilation Ventilation is an important factor that determines the heating rate in the tunnel roasting kiln. The air volume is properly matched, the fuel can be fully burned, the temperature is stable, and the normal temperature rise is ensured. Otherwise, the air volume is too large, not only can not heat up normally, but also blow the fire in the fire extinguishing box when it is serious.

(3) Timely adjust the temperature Timely temperature adjustment refers to the use of various equipment equipped with the kiln to adjust the temperature of the kiln in a timely manner according to the determined heating curve of the ignition and commissioning of the kiln.

(4) Timely cleaning After the ignition is put into production, the firebox car should be cleaned in time to avoid affecting the air intake in the combustion chamber of the firebox car.

(5) Get in the car in time The temperature change in the kiln changes with time and space (distance from the car end). When the temperature in the kiln rises to the required range, the blank car should be fed into the kiln. It is necessary to prevent the entering speed of the car from being too slow and causing the billet car to heat up and catch fire in the No. 4 parking lot.

(6) Do a good job in testing Do a good job in temperature and pressure detection, you can correctly guide the heating speed and entering speed. When the temperature of the fire box car reaches the product firing temperature, its position is just in the firing zone. At this time, the bricks enter the normal roasting, that is, the fire box car can be stopped. At this point, the ignition operation is complete.

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