ISSN 2594-357X
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Abstract
CSN´s Blast Furnace 3 produces around 10,000 t of hot metal per day. It has got four hot stoves operating in an automatic sequence. The hot stoves are responsible to regenerate the blast furnace gas enthalpy energy, heating the refractory in the gas cycle, and blowing the hot blast into the blast furnace in the blast cycle. The temperature of the cold air coming from the motoblower is around 200 °C. After going through the hot stoves, the air temperature is raised to around 1350°C, then it is injected into the mixing chamber together with the cold air. Thus, the blowing temperature in the ring off wind inside the blast furnace can be controlled. The main hot stove equipments are the hot blast valves, the air and combustion gas control valves, shut-off valves, refractory, refractory chamber, expansion joints, flow, pressure and temperature transmitters, plus the PLC, which is responsible for control. There are about 112 valves operating every hot stove changeover. The hot stove original changeover sequence, design by NKK/Japan, was fixed timer by the operator between 40 to 50 minutes according to the desired temperature and blast furnace flow. When the timer is elapsed, the hot stoves start the changeover process. The next hot stove is put in the blast cycle, and the older hot stove in blow cycle is box-up and goes to gas cycle. The number of hot stoves changeover per day was around 28 up to 36 at single blow mode, and approximately from 14 up to 18 changeovers CParallel blow mode, when two hot stoves blows together. The new strategic based in the thermal control was design to preserve the hot stoves into blast until they can hold the desired temperature at that blast flow. The timers are hold just before they got elapsed according to the hot blast thermal capacity remained which is on-line measured and estimated. The thermal control changeover instead of fixed timers optimized the use of the hot stoves decreasing the pressure equalizations and valve operations in general. The number of hot stoves changeover per day with the new control decreased around 16 up to 20 at single blow mode, and approximately from 8 up to 10 changeovers C-Parallel blow mode, when two hot stoves blows together. The developments carried out raised the blast flow average temperature up to about 100°C, saving 10 kg/t hot metal in the coke rate.
CSN´s Blast Furnace 3 produces around 10,000 t of hot metal per day. It has got four hot stoves operating in an automatic sequence. The hot stoves are responsible to regenerate the blast furnace gas enthalpy energy, heating the refractory in the gas cycle, and blowing the hot blast into the blast furnace in the blast cycle. The temperature of the cold air coming from the motoblower is around 200 °C. After going through the hot stoves, the air temperature is raised to around 1350°C, then it is injected into the mixing chamber together with the cold air. Thus, the blowing temperature in the ring off wind inside the blast furnace can be controlled. The main hot stove equipments are the hot blast valves, the air and combustion gas control valves, shut-off valves, refractory, refractory chamber, expansion joints, flow, pressure and temperature transmitters, plus the PLC, which is responsible for control. There are about 112 valves operating every hot stove changeover. The hot stove original changeover sequence, design by NKK/Japan, was fixed timer by the operator between 40 to 50 minutes according to the desired temperature and blast furnace flow. When the timer is elapsed, the hot stoves start the changeover process. The next hot stove is put in the blast cycle, and the older hot stove in blow cycle is box-up and goes to gas cycle. The number of hot stoves changeover per day was around 28 up to 36 at single blow mode, and approximately from 14 up to 18 changeovers CParallel blow mode, when two hot stoves blows together. The new strategic based in the thermal control was design to preserve the hot stoves into blast until they can hold the desired temperature at that blast flow. The timers are hold just before they got elapsed according to the hot blast thermal capacity remained which is on-line measured and estimated. The thermal control changeover instead of fixed timers optimized the use of the hot stoves decreasing the pressure equalizations and valve operations in general. The number of hot stoves changeover per day with the new control decreased around 16 up to 20 at single blow mode, and approximately from 8 up to 10 changeovers C-Parallel blow mode, when two hot stoves blows together. The developments carried out raised the blast flow average temperature up to about 100°C, saving 10 kg/t hot metal in the coke rate.
Keywords
Blast furnace; Hot stoves; Thermal control; Changeover.
Blast furnace; Hot stoves; Thermal control; Changeover.
How to refer
Motta, Ricardo Sebastião Nadur;
Costa, Waldir Benedito da;
Soares, Thiago Guimarães;
Souza., Luíz Edival de.
BLAST FURNACE HOT STOVE CHANGEOVER
BY THERMAL CONTROL
,
p. 80-90.
In: 42º Seminário de Redução de Minério de Ferro e Matérias-primas / 13º Seminário Brasileiro de Minério de Ferro / 6th International Congress on the Science and Technology of Ironmaking,
Rio de Jabeiro,
2012.
ISSN: 2594-357X
, DOI 10.5151/2594-357X-21537
