Hot blast stove automatic control in staggered parallel operation
Technical principle:
In order to make the blast furnace hot blast temperature stability is obtained, by adjusting the hot blast stove system mixed air control valve is the hot wind down and stabilized at a value. This is commonly used in current domestic blast furnace hot blast temperature control. But this method needs to be mixed with the cold air to the ratio of hot air, so from the total calorific value of the air supply to reduce the amount of wind, the wind is naturally low.
"Staggered parallel heat" send wind not by mixing air regulating valve mixing with cold wind to control into the blast furnace air temperature, but through the first furnace low air temperature was mixed furnace high wind temperature, through the different volume ratio of finally get stable temperature. Due to using staggered parallel heat when first furnace air temperature is much higher than the existing air supply mode by mixing air valve into the cold wind temperature, so staggered parallel heat air gross calorific value is higher than the gross calorific value of existing air supply mode, sent the same amount of wind, air temperature naturally to higher than the existing supply air temperature.
Through the No. 5 blast furnace of Wuhan Iron and Steel Company interleaved air automatic control system using the situation, in the original annual average air temperature of 1150℃, does not change the hot blast stove burning furnace calorific value case, by using a staggered parallel air automatic control, can be stably and effectively improve supply air temperature of 50℃, and whether in normal air supply or changing the furnace and air temperature can be stable in +/-5~10℃ temperature range. Whether it is saving energy and reducing consumption or stabilizing blast furnace production, the automatic control system of the hot blast stove staggered parallel system has excellent performance.
Staggered parallel cool and heat parallel air way: the conventional interleaved parallel cool "air supply technology, four hot blast stove combustion two feed and two blowing hot air furnace are divided into the first half cycle and the second half of the cycle time, in time to send the wind staggered half a cycle of parallel air supply. For example: when the No.1 blast furnace in the second half of the cycle and No.2 blast furnace of half cycle parallel blowing, sent 50% hot air, when the No.1 blast furnace end air go to burning, No.2 blast furnace in the second half of the cycle and No.3 blast furnace in front of the half cycle of parallel air, each send 50% hot air. With the reduction of heat storage in the grid brick of hot blast furnace, the air temperature of the blast furnace is gradually reduced in the whole parallel feeding period. At home and abroad, the vast majority of large and medium sized blast furnace in order to enter the blast furnace to keep the wind temperature is basically constant, are used against the cold wind to meet the requirements of the. In each air cycle begins, due to the two blast furnace mixed air temperature higher, much against the cold wind, with mixed air temperature decreased correspondingly reduced against the cold wind to single oven air cycle to reach the end stop against the cold. The wind temperature, which is not against the cold wind, has become a relatively constant wind temperature into the blast furnace. Using this conventional process, it is necessary to make the whole air supply cycle will have been in the wind and temperature to cool the use of cooling, just before and after the cooling.
The staggered parallel heat process, as well as two blast furnace interleaved air supply, different is two blast furnace air supply are not fixed in 50%, at the same time in the first half cycle of the hot blast stove blast temperature is higher, in the second half of the cycle of hot blast stove blast temperature is low. The high precision hydraulic control valve to control air valve opening, by changing two stoves air volume ratio to maintain a relatively constant temperature air into the blast furnace. First half cycle of hot blast stove air flow in the gradually increased from 0 to 100%. At the same time, in the second half cycle hot blast stove air volume from 100% gradually reduced to 0%, any time two hot blast stove air addition is 100%, by adjusting the two blast furnace by air ratio method can also reach into the blast furnace air temperature relatively constant, because it is not against the wind. So it obtains the improving effect of temperature and wind.
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