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Burner devices

1. Ceramic burners for combustion chambers of hot blast stoves

Steel burners of “pipe-in-pipe” type are normally used for heating of hot blast stoves with conventional internal combustion chamber in Russia. Since these burners are arranged horizontally, the stream of burning gas at the outlet of the burner nozzle impacts the opposite vertical wall of the combustion chamber, which leads to spot overheating of the brickwork in the bottom part of combustion chamber. The overheating of the brickwork in this part of the chamber is the main reason of its collapse owing to the creep of refractory under the influence of high temperatures and static load of the brickwork. The local hot spot creates also high thermal stresses and leads to formation of through cracks in the bricks up to the checker-work, resulting in short circuiting phenomenon.

One of the ways to eliminate the above design faults is introduction of ceramic burners with the axial location of flame in the combustion chamber (see Fig. 1) and, hence combustion of gas is also in the vertical axis. Such burners provide a long flame and they promote transfer of the maximum temperatures to the top part of the combustion chamber where the brickwork dead load is less. Due to such a design improvement, a harmful effect of refractory creep on the performance of the combustion chamber is reduced, and its service life is increased.
Gas and combustion air are supplied into the ceramic burner through two separate connecting branches. The air, supplied to the peripheral ring header, passes through the slot-hole channels and is injected via several ports to the central gas stream arranged along the combustion chamber vertical axis. It is necessary to provide a uniform distribution of gas and air in the outlet section of the burner and a steady combustion of gas in an axially symmetric torch with a stable of ignition.
Experts of our company participated in the development of ceramic burners of different capacities for various types of hot blast stoves. KALUGIN JSC can carry out a project for installation of ceramic burners of its own proven design in any type of hot blast stoves. However, the application of such burners allows removing only one of the disadvantages of existing hot blast stoves combustion chambers (the phenomenon of creep) and does not cardinally resolve the problem of the total service life of hot blast stoves. These problems have been resolved only in the shaftless stove of Kalugin design (KSS) and we advise our clients that the only and the best option to increase the hot blast temperature, to extend the inter-reline service life, to obtain significant savings in capital costs and to improve ecological parameters of operation is replacement of the conventional stoves with the KSS.
Fig. 1 – Design of industrial ceramic burner for combustion chamber Photo 1 – Starting burner for KSS Photo 2 – Starting burner for KSS
2. Starting burners
 
Drying-out and heating-up of hot blast stoves is the initial stage of their commissioning and should be carried out safely and meticulously, because in many respects the drying and heating procedure defines the performance of stoves in future. Therefore on each KSS in the drying-out and heating-up period there is installed a special start-up burner of KALUGIN JSC design (see Photos 1 and 2) using natural gas or coke oven gas. Such a burner operates with forced air supply and allows heating-up when the chimney draught is low or absent at all and there is overpressure (a hydraulic resistance) in the cold checker-work of the stoves. This usually occurs when the new KSS is connected to the flue of the operating hot blast stove system.
After the heating-up of KSS system is over and the main BF gas burners are ignited, start-up burners are disconnected, removed and sent to the equipment stores. They can also be retained if they disconnected from the KSS by water-cooled shut-off valve, which can be specifically introduced in the design.
Besides, the start-up burner can be used to hold a high operating temperature in the hot stove with silica dome and upper part of the checker-work during a long blast furnace shutdown for repair so that the stoves can be kept hot for an extended time regardless of the blast furnace (“idle mode”).
The burners have independent supply for natural gas (CO gas) and are equipped with the system of flame control based on flame detectors, by a thermocouple and safety automatics (see Photo 3) to shut-off the burner in case of flame failure or any other malfunctioning of the system.
The main feature of the burner design is the capability to operate with a large excess of air (up to α=10-12) without flame-failure which is required at the initial stage of heating of hot blast stoves controlled at low temperatures of dome, when the burner must provide the temperature of combustion products about 200ºC.
The complete set of start-up burner for each KSS also includes: A Pilot burner, a flow control valve, transition tube, axial fan (see Photo 2) and regulating piece (Photo 4).
Our company – KALUGIN JSC – carries out development and supply of starting burners for hot stoves, and also is ready to develop and supply similar burners per corresponding Customer’s reques
Photo 4 – Regulator piece of the starting burner Photo 3 – Control panel of automation system in the starting burner
3. Other types of burner devices
 
KALUGIN JSC has the license for developing, designing and testing of non-standard equipment and, in particular, burner devices. The experts from our company have wide experience in this direction and repeatedly participated in projects of such gas-burning devices like after-burners of blast furnace gas and coke oven gas for iron & steel enterprises (their other name is gas dumping devices), etc.