An economical and environmentally friendly method for starting the converter dust removal fan combination

Abstract

The invention relates to the technical field of wet dust removal system for converter in metallurgical steel industry, and specifically discloses an economical and environmentally friendly method for starting a combined dust removal fan for a converter, comprising the following steps: 1) after each system of the converter is tested and confirmed to be normal, determining a time point for drying the converter; 2) starting secondary dust removal of the converter 10 minutes in advance of the time point, and achieving a high-speed operation state of secondary dust removal; 3) igniting and drying the furnace for 40-50 minutes, observing that the flame and smoke at the furnace mouth are relatively large, and smoke and dust begin to diffuse in the factory building, maintaining the high-speed operation state of secondary dust removal, and starting tertiary dust removal; 4) continuing to dry the furnace for 30 minutes, observing that the flame behind the furnace is obviously bright and there is no more thick smoke, starting primary dust removal, and maintaining the primary dust removal at a low speed of 1200r / min until the drying of the furnace is completed; the invention eliminates the situation that three tubes emit yellow smoke when the converter is dried under a traditional wet dust removal system, completely solves the environmental protection problem caused by smoke overflow, and reduces the consumption cost of oxygen.

Description

Technical Field

[0001] The invention relates to the technical field of wet dust removal systems for converters in the metallurgical steel industry, and in particular to an economical and environmentally friendly method for starting a combined converter dust removal fan. Background Art

[0002] The 60t converter production line of the steel plant adopts traditional wet OG dust removal. The flue gas generated by converter steelmaking is divided into three treatments. The primary dust removal system is a flue gas treatment system in which the primary flue gas enters the purification and recovery system through the vaporization flue. It mainly collects the flue gas during oxygen blowing during steelmaking and recovers the converter gas. The secondary dust removal system is a flue gas treatment system in which the secondary flue gas enters the bag filter through the auxiliary flue and then enters the chimney through the fan. It mainly collects the flue gas when the converter is adding molten iron, adding scrap steel and discharging slag. The tertiary dust removal system is to set up a smoke exhaust hood on the top of the converter building. After the smoke escaping from the primary and secondary dust removal systems enters the smoke exhaust hood, it enters the bag filter through the pipe, and finally enters the chimney through the fan for discharge. It mainly collects the smoke that escapes from the converter span and high-rise frame to the roof.

[0003] A new converter needs to be baked. The traditional practice is to confirm that the primary, secondary and tertiary dust removal fans are in place and operating normally, then add the ignited coke (about 6-7t) into the converter and start baking the furnace.

[0004] Current problems:

[0005] 1. When the 60t converter is being baked, coke is poured into the furnace at one time. The small amount of sulfur-containing impurities brought by the coke and the moisture and asphalt mixed in the refractory materials of the furnace lining will cause a high dust concentration in the flue gas produced by oxygen blowing in the early stage of the baking furnace. Most of the flue gas enters the primary dust removal, and the water seal cannot effectively seal the flue gas, resulting in yellow smoke from the three pipes, polluting the air and causing environmental accidents.

[0006] 2. The dust removal system has a strong smoke absorption capacity when the primary, secondary and tertiary dust removal are turned on at the same time. The heat from the burning coke cannot stay in the furnace for a long time, and the heat utilization rate is low, resulting in a large amount of coke usage, a long furnace baking time and a large oxygen consumption. Therefore, it is necessary to design an economical and environmentally friendly converter dust removal fan combination opening method to solve the problem that the dust removal system cannot meet the environmental emission requirements during the converter baking period, especially the dust removal water seal in the early stage of the baking cannot completely and effectively purify the smoke with a large dust content, resulting in yellow smoke from the three pipes of the plant; the converter baking has high economic costs and low work efficiency. Summary of the invention

[0007] In view of the problems existing in the prior art, the object of the present invention is to provide an economical and environmentally friendly method for opening a converter dust removal fan combination.

[0008] The technical solution adopted by the present invention to solve the technical problem is: an economical and environmentally friendly converter dust removal fan combination opening method, comprising the following steps:

[0009] 1) After the converter systems are tested and confirmed to be normal, determine the time for the converter to be baked;

[0010] 2) Start the converter secondary dust removal 10 minutes in advance, and gradually increase the secondary dust removal speed to 460r / min within 10 minutes to achieve high-speed operation of the secondary dust removal;

[0011] 3) Ignite the furnace and bake for 40-50 minutes. Observe that the flame and smoke at the furnace mouth are relatively thick and smoke begins to diffuse in the factory. Keep the secondary dust removal running at high speed, turn on the tertiary dust removal, and keep the tertiary dust removal running at a high speed of 790r / min;

[0012] 4) Continue to bake the furnace for 30 minutes, observe that the flame behind the furnace is obviously brighter and there is no more thick smoke, keep the secondary and tertiary dust removal running, turn on the primary dust removal, and keep the primary dust removal running at a low speed of 1200r / min until the end of the baking.

[0013] Specifically, after the ignition and drying of the furnace in step 3), the secondary dust removal operation is continued. At this time, due to the large amount of coke accumulated in the furnace, the oxygen flow rate is relatively small, 5000-8000m 3 / h, and the refractory material of the furnace lining contains more moisture and asphalt, so the coke cannot be completely burned in the early stage of furnace baking. The main components of the flue gas include CO, CO 2 The smoke is a dark brown complex mixture of hydrocarbons and their non-metallic derivatives produced by the combustion of gases, sulfides, and asphalt. After entering the secondary dust removal, the smoke is pressed into the back-blowing bag filter for purification and is directly discharged into the atmosphere through the upper shutter of the dust collector. The dust concentration is less than 15mg / Nm 3 .

[0014] Specifically, after 40-50 minutes of ignition of the drying furnace in the step 3), the temperature in the furnace has risen to above 400°C. At this time, the degree of reaction in the drying furnace is greatly accelerated, and smoke escaping from the secondary dust removal is observed to begin to diffuse in the factory. The tertiary dust removal system is turned on, and the speed is gradually increased to a high-speed operation state of 790r / min. The escaping smoke passes through the exhaust hood, enters the bag filter, and then enters the chimney through the fan for discharge.

[0015] Specifically, the furnace is baked for 70-80 minutes in step 4), the temperature in the furnace rises to above 800°C, the moisture and asphalt contained in the refractory material of the furnace lining are completely evaporated, the coke is more than half burned, the furnace is in an oxygen-rich state, and the main components of the flue gas are CO, CO 2The volatile substances composed of gases and other hydrocarbons have low dust concentration but high flue gas temperature. At this time, the primary dust removal is turned on. The flue gas is cooled by the gasification cooling flue, and then further cooled and dusted. Finally, it enters the discharge tower through the three-way switching valve for ignition and discharge. At this stage, the secondary and tertiary dust removals operate normally. The primary dust removal only needs to maintain a low speed of 1200r / min to purify the flue gas with low dust content.

[0016] The present invention has the following beneficial effects:

[0017] The economical and environmentally friendly converter dust removal fan combination start method designed by the present invention eliminates the situation that the three tubes emit yellow smoke when the converter is baked under the traditional wet dust removal system. By formulating the technical scheme of the start sequence and start time of the dust removal fan during the baking period, the dust removal system meets the national environmental emission standards and completely solves the environmental protection problem caused by the overflow of smoke.

[0018] By formulating technical solutions for different fan operation time and speed, the heat from coke combustion can be retained in the furnace for a long time, the heat utilization rate is increased, and the furnace baking cost is more economical and efficient. The amount of coke used can be reduced from 6-7t to 4±0.5t, a reduction of about 30%; the furnace baking time is reduced from 160-180min to 90-110min, a reduction of about 40%; the furnace oxygen consumption is reduced from 21000-24000m 3 Reduced to 12000-14700m 3 It is about 40% lower than before, which not only greatly improves oxygen recovery but also reduces the oxygen consumption cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the time sequence diagram of the fan turning on during the oven baking process.

[0020] Figure 2 It is a line graph of the baking time and the temperature change inside the baking furnace. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely further describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Embodiment 1:

[0023] like Figure 1-2 As shown, a method for starting the dust removal fan combination when the converter is drying the furnace, the specific technical scheme is as follows:

[0024] 1. After the test run of each converter system is completed and confirmed to be normal, start the secondary dust removal 10 minutes before the planned furnace drying, and gradually increase the secondary dust removal speed to 460r / min within 10 minutes to achieve high-speed operation of the secondary dust removal.

[0025] 2. After the furnace is ignited, continue to maintain the secondary dust removal operation. At this time, due to the large amount of coke accumulated in the furnace, the oxygen flow rate is small (5000-8000m 3 / h), and the refractory material of the furnace lining contains more moisture and asphalt. Therefore, the coke cannot be completely burned in the early stage of furnace baking. The main components of the flue gas include CO, CO 2 The smoke is a dark brown complex mixture of hydrocarbons and their non-metallic derivatives produced by the combustion of gases, sulfides, and asphalt. After entering the secondary dust removal, the smoke is pressed into the back-blowing bag filter for purification and is directly discharged into the atmosphere through the upper shutter of the dust collector. The dust concentration is less than 15mg / Nm 3 This solution uses bag dust removal instead of wet water seal to filter smoke dust particles, solving the problem that the water seal cannot seal the smoke dust in the early stage of the drying furnace.

[0026] 3. As the oven is baked, the temperature inside the oven continues to rise. Referring to the oven heating curve, the temperature inside the oven has risen to 400°C after 40 minutes of baking. At this time, the reaction in the oven is greatly accelerated. We can observe that smoke escaping from the secondary dust removal system begins to diffuse in the factory. The tertiary dust removal system is turned on, and the speed is gradually increased to a high-speed operation state of 790r / min. The escaping smoke passes through the exhaust hood, enters the bag filter, and then enters the chimney through the fan for discharge. At this stage, the secondary and tertiary dust removals work together to prevent smoke from overflowing into the outside of the factory.

[0027] 4. The furnace is baked for 70-80 minutes. The temperature inside the furnace rises to above 800℃. The moisture and asphalt contained in the refractory materials of the furnace lining are basically evaporated. The coke is also burned more than half. The furnace is in an oxygen-rich state. The main components of the flue gas are CO, CO 2 The volatile matter composed of gases and other hydrocarbons has low dust concentration, but the flue gas temperature is high. At this time, the primary dust removal is turned on. The flue gas is cooled by the gasification cooling flue, and then enters the first and second chambers for further cooling and dust removal. Finally, it enters the venting tower through the three-way switching valve for ignition and discharge. In this stage, the second and third dust removals are running normally, and the primary dust removal only needs to maintain a low speed of 1200r / min to purify the flue gas with low dust content.

[0028] The present invention is not limited to the above-mentioned implementation modes, and anyone should be aware of the structural changes made under the enlightenment of the present invention, and all those having the same or similar technical solutions as the present invention fall within the protection scope of the present invention.

[0029] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. An economical and environmentally friendly method for opening a converter dust removal fan assembly, characterized in that: The following steps are involved: 1) After the converter systems are tested and confirmed to be normal, determine the time for the converter to be baked; 2) Start the converter secondary dust removal 10 minutes in advance, and gradually increase the secondary dust removal speed to 460r / min within 10 minutes to achieve high-speed operation of the secondary dust removal; 3) Ignite the furnace and bake for 40-50 minutes. Observe that the flame and smoke at the furnace mouth are relatively thick and smoke begins to diffuse in the factory. Keep the secondary dust removal in high-speed operation. At this time, due to the large amount of coke accumulated in the furnace, the oxygen flow rate is relatively small, 5000-8000m 3 / h, and the refractory materials of the furnace lining contain more moisture and asphalt. Therefore, the coke cannot be completely burned in the early stage of the furnace baking. The main components of the flue gas include CO, CO2 gas, sulfide, hydrocarbons and non-metallic derivatives produced by the combustion of coke. The flue gas enters the secondary dust removal and is pressed into the back-blowing bag filter for purification. It is directly discharged into the atmosphere through the upper shutter of the dust collector. The dust concentration is less than 15mg / Nm 3 , start the three-stage dust removal and keep the three-stage dust removal running at a high speed of 790r / min; 4) Continue to bake the furnace for 30 minutes, observe that the flame behind the furnace is obviously brighter and there is no more thick smoke, keep the secondary and tertiary dust removal running, turn on the primary dust removal, and keep the primary dust removal running at a low speed of 1200r / min until the end of the baking.

2. The economical and environmentally friendly converter dust removal fan combination opening method according to claim 1 is characterized in that: The ignition furnace in the step 3) is kept for 40-50 minutes, and the temperature in the furnace has risen to above 400°C. At this time, the degree of reaction in the furnace is greatly accelerated, and smoke escaping from the secondary dust removal is observed to begin to diffuse in the factory. The tertiary dust removal system is turned on, and the speed is gradually increased to a high-speed operation state of 790r / min. The escaping smoke passes through the exhaust hood, enters the bag filter, and then enters the chimney through the fan for discharge.

3. The economical and environmentally friendly converter dust removal fan combination opening method according to claim 1 is characterized in that: The furnace is baked for 70-80 minutes in the step 4), the temperature in the furnace rises to above 800°C, the moisture and asphalt contained in the refractory material of the furnace lining are completely evaporated, and more than half of the coke is burned. The furnace is in an oxygen-rich state, and the main components of the flue gas are volatile substances composed of CO, CO2 gas and other hydrocarbons. The dust concentration is low, but the flue gas temperature is high. At this time, the primary dust removal is turned on, and the flue gas is cooled by the gasification cooling flue, and then further cooled and dusted, and finally enters the discharge tower through the three-way switching valve for ignition and emission. At this stage, the secondary dust removal and the tertiary dust removal are operating normally, and the primary dust removal only needs to maintain a low speed of 1200r / min to purify the flue gas with low dust content.

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