CN-116481329-B - System and method capable of adjusting use and consumption of circulating smoke

CN116481329BCN 116481329 BCN116481329 BCN 116481329BCN-116481329-B

Abstract

The invention belongs to the field of metallurgy, and relates to a system and a method for adjusting the use and the consumption of circulating flue gas, wherein the system comprises a drying furnace, a coal mill, a cloth bag powder collecting device and a coal dust blower which are sequentially connected, the coal mill is sequentially connected with a coal feeder and a raw coal bin, and the drying furnace is communicated with a chimney and a hot blast furnace through an exhaust gas induced draft fan; the pulverized coal fan is communicated with the drying furnace through a circulating flue gas pipeline. According to the invention, when the waste gas of the blast furnace hot blast stove is insufficient, the system can stabilize the temperature of the pulverizing system by adjusting the circulating smoke quantity entering the drying furnace of the pulverizing system, so that the water content of pulverized coal is ensured to be qualified. Meanwhile, in the shutdown process of the pulverizing system, a two-step strategy of the whole system cooling process is realized, namely, the pulverizing system is firstly cooled to a safe temperature range by continuously circulating inert circulating smoke with low oxygen content and low temperature. And then the powder making system is rapidly cooled by a large amount of cold air. Not only ensures the shutdown safety of the powder making system, but also improves the shutdown efficiency.

Inventors

TIAN GUOQING
YUAN DAILIAN
TANG LIANGBO
TAN HAIBO
LIU JINGBO
LIU XIANGHUI
CANG YUE
MA LI
YANG LIN
LI JUNFENG
Qi Wanbing

Assignees

重庆钢铁股份有限公司

Dates

Publication Date: 20260508
Application Date: 20230427

Claims (6)

1. The method is characterized in that the method is based on a system capable of adjusting the usage and the usage of the circulating flue gas, and the system comprises a drying furnace, a coal mill, a cloth bag powder collecting device and a coal dust fan which are sequentially connected, wherein the coal mill is sequentially connected with a coal feeder and a raw coal bin, and the drying furnace is communicated with a chimney and a hot blast furnace through an exhaust gas induced draft fan; A pipeline between the waste gas induced draft fan and the chimney is provided with a waste gas regulating valve, and a pipeline between the drying furnace and the coal mill is provided with a hot air valve; a hot air valve and a temperature monitoring point are sequentially arranged between the drying furnace and the coal mill, and the hot air valve and the temperature monitoring point are communicated to a first circulating smoke regulating valve on a circulating pipeline through a second circulating smoke regulating valve; the coal mill is provided with a nitrogen charging valve at the outlet of the coal mill communicated with nitrogen; The circulating smoke pipeline is provided with a circulating smoke stop valve and a first circulating smoke regulating valve; The method comprises the following steps: s1, preparing pulverized coal and adjusting the temperature of a system through circulating smoke; S11, in the normal operation process of the pulverized coal preparation system, when the oxygen content monitoring value at the rear end of the exhaust gas induced draft fan exceeds 8%, the exhaust gas amount generated by the blast furnace hot blast stove is insufficient, and the pulverized coal fan reversely pumps air into a pulverized coal system from a chimney; S12, gradually reducing the opening of the waste gas regulating valve, temporarily reducing the coal feeding amount of the coal feeder until the oxygen content of the waste gas of the hot blast stove pumped into the system is lower than 6%, and continuously stabilizing; S13, opening a circulating smoke stop valve and a fully-opened first circulating smoke regulating valve; s14, recovering the coal feeding quantity of the coal feeder; S15, as the temperature of the circulating flue gas is not high, after the circulating flue gas and the waste gas of the hot blast stove enter the drying furnace together, heat compensation is needed, and the gas combustion amount of the drying furnace is increased at the moment, and the inlet temperature of the coal mill is kept at 280 ℃, when the gas combustion amount of the drying furnace reaches the maximum inlet temperature of the coal mill or is lower than 260 ℃, the opening degree of a first circulating flue gas regulating valve is gradually reduced, and the circulating flue gas amount entering the drying furnace is reduced until the inlet temperature of the coal mill reaches a specified range; S16, in the process of adjusting the circulating flue gas amount, the burning condition of the hot blast stove is concerned at any time, and the opening of the waste gas adjusting valve and the opening of the first circulating flue gas adjusting valve are timely adjusted, so that the sufficient air amount and the stable temperature of the whole pulverizing system are ensured; s2, cooling the powder preparation system through circulating smoke and stopping; S21, immediately stopping gas supply of the drying furnace after receiving a shutdown notice of the powder preparation system, opening a circulating smoke stop valve, and opening an initial opening of a second circulating smoke regulating valve to 30% -40%; s22, gradually reducing the coal feeding amount of the coal feeder, reducing the opening of the waste gas regulating valve, and simultaneously increasing the opening of the second circulating smoke regulating valve, wherein the outlet temperature of the coal mill is kept below 75 ℃ in the coal feeding amount reducing process; s23, when the coal feeding amount is reduced to be less than 10t/h and the outlet temperature of the coal mill is stabilized to be less than 75 ℃, directly stopping the coal mill, and closely paying attention to the outlet temperature change of the coal mill, for example, opening a nitrogen charging valve of the outlet of the coal mill to charge nitrogen for cooling if the temperature exceeds 95 ℃; s24, when residual coal dust in the coal mill is confirmed to be completely extracted, closing an exhaust gas induced draft fan, opening a Guan Refeng valve and a drying furnace discharge valve, and cutting off the heat source of the whole front end of the coal mill; S25, fully opening a second circulating flue gas regulating valve, and firstly passing through a circulating flue gas cooling system, wherein heat is continuously lost in the circulating process of circulating flue gas, the temperature can gradually drop, after the outlet temperature of a coal mill is reduced to below 60 ℃ and the outlet temperature of a powder collecting device is reduced to below 50 ℃, a cold air stop valve is opened, and a large amount of cold air is pumped into the system to rapidly cool the system; S26, stopping the pulverized coal blower when the outlet temperature of the coal mill is lower than 40 ℃.
2. The method of claim 1, wherein an oxygen content monitoring point and an air quantity monitoring point are sequentially arranged between the waste gas induced draft fan and the drying furnace, a combustion-supporting fan and a combustion-supporting fan regulating valve are arranged on the drying furnace and are communicated with the coal gas through a coal gas regulating valve, and a pressure gauge and a bleeding valve for discharging are also arranged on the drying furnace.
3. The method of claim 2, wherein the raw coal bin is communicated with the coal feeder through a coal feeder inlet valve, a coal mill inlet valve is arranged between the coal feeder and the coal mill, and a temperature monitoring point is arranged on a pipeline of the coal mill, which is communicated with the bag powder collecting device.
4. The method of claim 3, wherein the top of the cloth bag powder collecting device is provided with a pulse powder blowing device for introducing nitrogen, the bottom of the cloth bag powder collecting device is respectively communicated with the coal powder bin through a discharging motor and a coal powder vibrating screen, and a pipeline connected with the coal powder blower of the cloth bag powder collecting device is further provided with a temperature monitoring point and a system air quantity regulating valve.
5. The method of claim 4, wherein in the step S12-S15, the control of the air quantity regulating valve of the system is noticed at any time according to the pressure change of the drying furnace, and the pressure of the drying furnace is kept within the range of-200 to +50 Pa in the adjusting process.
6. The method of claim 4, wherein in the step S21 to S23, the control of the air quantity regulating valve of the system is noticed at any time according to the pressure change of the drying furnace, and the pressure of the drying furnace is kept within the range of-200 to +50 Pa in the adjusting process.

Description

System and method capable of adjusting use and consumption of circulating smoke Technical Field The invention belongs to the field of metallurgy, and relates to a system and a method capable of adjusting the use and the consumption of circulating smoke. Background The coal powder preparation system mainly mixes waste gas of a blast furnace hot blast stove with high-temperature gas generated by burning coal gas of a drying furnace to dry coal powder. At present, the pulverized coal preparation systems in most iron and steel enterprises are provided with a smoke circulation function, but the circulation smoke is only used for making up the application of insufficient exhaust gas of the pulverizing system when the exhaust gas of the blast furnace hot blast stove is insufficient, and the application is single. Meanwhile, because the temperature of the circulating flue gas is lower, the circulating flue gas volume is not accurately controlled and regulated, and the temperature fluctuation of the powder process system is caused by excessive circulating gas volume entering a drying furnace of the powder process system in many cases, so that the condition of unqualified water content of coal dust is caused. Disclosure of Invention Therefore, the invention aims to provide a system and a method capable of adjusting the use and the consumption of circulating smoke, which can adjust the circulating smoke amount entering a drying furnace of a pulverizing system according to production requirements, ensure the temperature stability of the pulverizing system and ensure the qualification of the moisture of pulverized coal. The system comprises a drying furnace, a coal mill, a cloth bag powder collecting device and a coal dust blower which are sequentially connected, wherein the coal mill is sequentially connected with a coal feeder and a raw coal bin, the drying furnace is communicated with a chimney and a hot blast stove through an exhaust draught fan, and the coal dust blower is communicated with the drying furnace through a circulating flue gas pipeline. Optionally, an exhaust gas regulating valve is arranged on a pipeline between the exhaust gas induced draft fan and the chimney, an oxygen content monitoring point and an air volume monitoring point are sequentially arranged between the exhaust gas induced draft fan and the drying furnace, a combustion-supporting fan and a combustion-supporting fan regulating valve are arranged on the drying furnace and are communicated with coal gas through a coal gas regulating valve, a hot air valve is arranged on a pipeline, which is communicated with a coal mill, of the drying furnace, and a pressure gauge and a bleeding valve for discharging are also arranged on the drying furnace. Optionally, a hot air valve and a temperature monitoring point are sequentially arranged between the drying furnace and the coal mill, the hot air valve and the temperature monitoring point are communicated with a first circulating flue gas regulating valve on a circulating pipeline through a second circulating flue gas regulating valve, and a cold air stop valve for introducing air is further arranged between the hot air valve and the temperature monitoring point. Optionally, the coal feeder is communicated with a raw coal bin through a coal feeder inlet valve, a coal mill inlet valve is arranged between the coal feeder and the coal mill, a coal mill outlet nitrogen charging valve communicated with nitrogen is arranged on the coal mill, and a temperature monitoring point is arranged on a pipeline communicated with the cloth bag powder collecting device. Optionally, the top of the cloth bag powder collecting device is provided with a pulse powder blowing device for introducing nitrogen, the bottom of the cloth bag powder collecting device is respectively communicated to the coal powder bin through a discharging motor and a coal powder vibrating screen, and a pipeline connected with the coal powder fan of the cloth bag powder collecting device is also provided with a temperature monitoring point and a system air quantity regulating valve. Optionally, a circulating flue gas stop valve and a first circulating flue gas regulating valve are arranged on the circulating flue gas pipeline. The method for adjusting the usage and the usage of the circulating smoke comprises the following steps of: s1, preparing pulverized coal and adjusting the temperature of a system through circulating smoke; s11, when the oxygen content monitoring value at the rear end of the exhaust gas induced draft fan exceeds 8% in the normal operation process of the pulverized coal preparation system, the defect that the amount of exhaust gas generated by the blast furnace hot blast stove is insufficient is proved, and the pulverized coal fan reversely pumps air into a pulverized coal system from a chimney; S12, gradually reducing the opening of the waste gas regulating valve, temporarily reducing the coal feeding amount of the coal feede