阅读说明：本技术 一种超厚料层烧结蒸汽加湿保温的方法 (Super-thick material layer sintering steam humidifying and heat preserving method ) 是由 张辉 夏铁玉 刘佩江 李建军 李志斌 周明顺 段立祥 刘杰 李晓春 孙彬 翟立委 于 2021-06-28 设计创作，主要内容包括：一种超厚料层烧结蒸汽加湿保温的方法,将环冷机热废气与蒸汽混匀,然后将混匀气在双层烧结一次点火和二次点火后喷入烧结料层,既可以保证上层有足够的热量,提高表层烧结矿质量；又可以将大量蒸汽由热风带入烧结料层内部,生成助燃气体一氧化碳和氢气,促进烧结过程,缩短烧结时间。(A method for humidifying and insulating sintering steam of an ultra-thick material layer is characterized in that hot waste gas of a circular cooler is uniformly mixed with the steam, and then the mixed gas is sprayed into the sintering material layer after primary ignition and secondary ignition of double-layer sintering, so that enough heat can be ensured on the upper layer, and the quality of surface layer sintering ore is improved; and a large amount of steam can be brought into the sintering material layer by hot air to generate combustion-supporting gases of carbon monoxide and hydrogen, so that the sintering process is promoted, and the sintering time is shortened.)

1. The super-thick material layer sintering steam humidifying and heat insulating method is characterized in that mixed gas of hot air and steam is sprayed on the sintering material surface after the first ignition and the second ignition of double-layer sintering, and humidification and heat insulation are carried out, and the method specifically comprises the following steps:

(1) the thickness of the sintering material which is firstly distributed and added on the sintering machine trolley is 500 mm-700 mm, and the sintering material is firstly ignited by a first igniter for air draft sintering; a first steam hot air humidifying and heat preserving cover is arranged above a sintering material surface which is 5-20 m from the first igniter along the running direction of the trolley;

(2) dedusting hot air at the low-temperature section of the circular cooler by a deduster, uniformly mixing the dedusted hot air with steam, humidifying the mixture, introducing a first steam hot air humidifying and heat preserving cover, and humidifying and preserving heat of a sinter bed of the first ignition system;

(3) when the sintering pallet is moved to the total length of the sintering machineThen, performing secondary material distribution on the surface of the sintered ore which is being sintered, wherein the thickness of the secondary material distribution is 300-500 mm, and performing secondary ignition, air draft and sintering by a second igniter; a second steam hot air humidifying and heat preserving cover is arranged above the sintering charge level from the second igniter along the trolley running direction by 5-25 m;

(4) and (3) dedusting hot air in the medium temperature section of the circular cooler by a deduster, uniformly mixing the dedusted hot air with steam, humidifying the mixture, introducing a second steam hot air humidifying and heat preserving cover, and humidifying and preserving heat of a sinter bed of the second ignition system.

2. The super-thick bed sintering steam humidification and insulation method according to claim 1, wherein the first steam hot air humidification and insulation cover is provided with a telescopic joint.

3. The super-thick bed sintering steam humidification and insulation method according to claim 1, wherein the second steam hot air humidification and insulation cover is provided with a telescopic joint.

4. The super-thick material layer sintering steam humidification and heat preservation method according to claim 1, characterized in that the sum of the first material distribution thickness and the second material distribution thickness is greater than or equal to 900mm and less than or equal to 1200 mm.

5. The super-thick material layer sintering steam humidifying and heat preserving method according to claim 1, characterized in that hot air and steam are fully mixed in a hot air steam mixing device; after the hot air and the steam are mixed uniformly, the moisture content of the mixed steam is less than or equal to 1.5 wt%.

6. The super-thick material layer sintering steam humidification and heat preservation method according to claim 1, characterized in that in the step (2), the hot air temperature of the low-temperature section of the circular cooler is 240-280 ℃, the steam temperature is 240-280 ℃, the mass fraction of the steam in the hot air-steam mixed gas is 6-15%, and the steam pressure is controlled to be 0.3-0.6 MPa.

7. The super-thick material layer sintering steam humidification and heat preservation method according to claim 1, characterized in that in the step (4), the hot air temperature of the medium temperature section of the circular cooler is 300-350 ℃, the steam temperature is 280-340 ℃, the mass fraction of the steam in the hot air-steam mixed gas is 16-25%, and the steam pressure is controlled to be 0.6-0.9 MPa.

Technical Field

The invention relates to the technical field of iron-making production, relates to a sintering production technology, and particularly relates to a super-thick material layer sintering steam humidifying and heat preserving method.

Background

The thick material layer sintering is an important widely-adopted sintering technology, and has the advantages of improving the strength of sintered ore, reducing sintering fuel consumption and the like, but the application of the thick material layer sintering technology also faces some difficulties. Along with the thickening of the sinter bed, the airflow resistance passing through the sinter bed is increased, the sintering speed is reduced, the power consumption of a fan is increased, the sintering productivity is reduced, and particularly for enterprises taking iron concentrate powder as a main sintering raw material. Technicians do a lot of work on the aspect of improving the air permeability of the material layer, control the proper alkalinity level and moisture content of raw materials, strengthen the granulation of the mixture, mix large particles in the sintering material, use various measures such as a material loosening device and the like to improve the air quantity passing through the sintering material layer, but still can not meet the requirement of the sintering production of the super-thick material layer, and limit the yield and the quality of the sintering ore.

In order to improve the technical and economic indexes of sintering production, including yield, quality, energy consumption, equipment life and the like, technicians do a lot of sintering exploration on thick (material layer height is over 800 mm) material layers: however, the method still adopts one-time ignition, adopts high negative pressure and large air flow straight-flow type air draft operation, tries to improve the thickness of the material layer in such a way, but actually, the surface of the thick material layer is often melted by one-time ignition, gaps among the material layers are blocked, the resistance of the whole material layer is increased, in order to maintain the operation, the negative pressure and the air flow of the fan must be increased, and as a result, on one hand, the local short circuit of the air flow is caused, the whole material layer cannot be sintered uniformly, on the other hand, the energy consumption is greatly increased, the expected purpose is not achieved, and the progress has not been made so far. The search of the skilled worker in the direction of sintering of very thick layers has not made a breakthrough, which means that the existing sintering processes and sintering plants are no longer adapted to the new production situation, which limits the further development of the productivity.

In order to ensure that sintering materials on the sintering machine are completely and completely sintered, enough combustion time needs to be provided for the vertical sintering process, so that the machine speed of the sintering machine needs to be controlled, and the mixed raw materials can be ensured to have enough time to fully react on the sintering trolley. The heat exchange between the air and the material layer is also related to the specific heat of the air and the air permeability of the material layer. There are two ways to enhance the heat exchange between the air and the material layer: one is to increase the air quantity sucked by the material layer, which can be realized by increasing the air permeability of the mixture and increasing the air suction quantity of the main exhaust fan, and the method has a bottleneck and is not easy to implement; another approach is to increase the air specific heat. In the steam humidification, a steam pipeline is laid to the middle and rear material surfaces of the sintering machine, and steam injection is carried out on the sintering material surface, and the specific heat of the steam is 1.8 times of that of the dry air, so that the specific heat of the air can be improved by injecting the steam on the sintering material surface. Therefore, the same amount of air and steam enter the material layer to form stronger heat exchange capacity and improve the vertical sintering speed, but the steam sprayed by the technology is not easy to enter the sintering material layer.

The hot gas sintering (hot gas sintering) refers to an iron ore sintering process in which a sintering machine is ignited and then sintered by hot air or hot waste gas at 300-1000 ℃. The conventional sintering process relies on air at room temperature for sintering after sintering ignition. Because of the automatic heat storage function in the sintering process, the sintering temperature of the upper part of the material layer is low, the sintering temperature of the lower part is high, so that the upper part is often insufficiently sintered, the liquid phase amount is insufficient, the strength of the obtained sintered ore is low, a plurality of return ores are formed, and the lower part is excessively fused due to the overhigh sintering temperature, so that the reducibility of the sintered ore is deteriorated. The ideal sintering regime is to make the sintering temperature uniform along the height of the bed. The hot air sintering is to continuously provide heat to the material layer by hot air after ignition so as to supplement the heat of the upper layer, so that the sintering temperature of the upper material layer and the lower material layer is relatively uniform, but the moisture fluctuation of the sintering material layer is easily caused by the hot air sintering.

Disclosure of Invention

The invention aims to provide a method for humidifying and preserving heat of super-thick material layer sintering steam, which is characterized in that hot waste gas of a circular cooler is uniformly mixed with the steam, and then the mixed gas is sprayed into a sintering material layer after primary ignition and secondary ignition of double-layer sintering, so that enough heat on the upper layer can be ensured, and the quality of surface layer sintering ores is improved; and a large amount of steam can be brought into the sintering material layer by hot air to generate combustion-supporting gases of carbon monoxide and hydrogen, so that the sintering process is promoted, and the sintering time is shortened.

In order to achieve the purpose, the invention adopts the following technical scheme:

the super-thick material layer sintering steam humidifying and heat insulating method is characterized in that mixed gas of hot air and steam is sprayed on the sintering material surface after the first ignition and the second ignition of double-layer sintering, and humidification and heat insulation are carried out, and the method specifically comprises the following steps:

(1) the thickness of the sintering material which is firstly distributed and added on the sintering machine trolley is 500 mm-700 mm, and the sintering material is firstly ignited by a first igniter for air draft sintering; a first steam hot air humidifying and heat preserving cover is arranged above a sintering material surface which is 5-20 m from the first igniter along the running direction of the trolley;

(2) dedusting hot air at the low-temperature section of the circular cooler by a deduster, uniformly mixing the dedusted hot air with steam, humidifying the mixture, introducing a first steam hot air humidifying and heat preserving cover, and humidifying and preserving heat of a sinter bed of the first ignition system;

(3) when the sintering pallet is moved to the total length of the sintering machineThen, performing secondary material distribution on the surface of the sintered ore which is being sintered, wherein the thickness of the secondary material distribution is 300-500 mm, and performing secondary ignition, air draft and sintering by a second igniter; a second steam hot air humidifying and heat preserving cover is arranged above the sintering charge level from the second igniter along the trolley running direction by 5-25 m;

(4) and (3) dedusting hot air in the medium temperature section of the circular cooler by a deduster, uniformly mixing the dedusted hot air with steam, humidifying the mixture, introducing a second steam hot air humidifying and heat preserving cover, and humidifying and preserving heat of a sinter bed of the second ignition system.

(5) And optimally adjusting the negative pressure of air draft to ensure that the sintering materials on the upper layer and the lower layer reach the sintering end point simultaneously to obtain the finished sintering ore.

The first steam hot air humidifying heat-preserving cover is provided with an expansion joint for adjusting the distance between the first steam hot air humidifying heat-preserving cover and the sintering charge level.

The second steam hot air humidifying heat-preserving cover is provided with an expansion joint for adjusting the distance between the second steam hot air humidifying heat-preserving cover and the sintering charge level.

The sum of the thickness of the first cloth and the thickness of the second cloth is larger than or equal to 900mm and smaller than or equal to 1200 mm.

Fully mixing hot air and steam in a hot air and steam mixing device; after the hot air and the steam are mixed uniformly, the moisture content of the mixed steam is less than or equal to 1.5 wt%.

In the step (2), the hot air temperature of the low-temperature section of the circular cooler is 240-280 ℃, the steam temperature is 240-280 ℃, the steam accounts for 6-15% of the mass fraction of the hot air-steam mixed gas, and the steam pressure is controlled to be 0.3-0.6 Mpa.

In the step (4), the hot air temperature of the medium temperature section of the circular cooler is 300-350 ℃, the steam temperature is 280-340 ℃, the steam accounts for 16-25% of the mass fraction of the hot air-steam mixed gas, and the steam pressure is controlled to be 0.6-0.9 Mpa.

Compared with the prior art, the invention has the beneficial effects that:

1) the invention uniformly mixes the hot waste gas of the circular cooler with the steam and sprays the material surface, thereby not only ensuring that the upper layer has enough heat and improving the quality of surface layer sinter, but also solving the problem of material layer moisture fluctuation caused by single hot air sintering.

2) The invention uniformly mixes the hot waste gas of the circular cooler with the steam and sprays the material surface, which not only can bring a large amount of steam into the sintering material layer by hot air to generate combustion-supporting gases of carbon monoxide and hydrogen, promote the sintering process and shorten the sintering time, but also can solve the problem that the steam is not easy to enter the sintering material layer when being sprayed independently.

Drawings

FIG. 1 is a schematic diagram of the structure of the device of the present invention.

In the figure: 1-a first distribution system; 2-a first ignition system; 3-a first steam hot air humidifying and heat preserving cover; 4-a second material distribution system; 5-a second ignition system; 6-a second steam hot air humidifying and heat preserving cover; 7-an electromagnetic switch; 8-sintering trolley; 9-a star wheel; 10-an air draft system; 11-sintering the flue gas main pipeline; 12-a discharge crushing device; 13-telescopic joint.

Detailed Description

The present invention is described in more detail by way of examples, which are merely illustrative of the best mode of carrying out the invention and are not intended to limit the scope of the invention in any way.

Example 1:

a method for humidifying and insulating the sintered steam of super-thick material layer includes such steps as spraying the mixture of hot air and steam onto the surface of sintered material after the first and the second ignition of double-layer sintering, and humidifying and insulating.

The thickness of the sintering material which is firstly distributed and added on the sintering machine trolley is 650mm, and the sintering material is firstly ignited by a first igniter for air draft sintering; a first steam hot air humidifying and heat preserving cover is arranged above the sintering material surface which is 12m from the first igniter along the running direction of the trolley. And adjusting the telescopic joint of the first steam hot air humidifying and heat preserving cover to ensure that the distance between the first steam hot air humidifying and heat preserving cover and the sintering charge surface is 120 mm. Dedusting hot air at a low-temperature section of the circular cooler at 280 ℃ by a deduster, fully mixing the dedusted hot air with steam in a hot air and steam mixing device, humidifying the mixture, and introducing a first steam and hot air humidifying and heat preserving cover to humidify and preserve the sintering charge surface with the thickness of 0-12 m of a first ignition system; the water content of the hot air-steam mixed gas is controlled to be 0.8%. The mass fraction of the steam in the hot air and steam mixed gas is 13 percent; the steam temperature is controlled at 255 deg.C and the pressure is controlled at 0.4 MPa.

When the sintering pallet is moved to the total length of the sintering machineThen, performing secondary material distribution on the surface of the sintered ore which is being sintered, wherein the thickness of the secondary material distribution is 350mm, and performing secondary ignition air draft sintering by using a second igniter; a second steam hot air humidifying and heat preserving cover is arranged above the sintering charge level 20m from the second igniter along the running direction of the trolley; adjusting the expansion joint of the second steam hot air humidifying and heat preserving cover to enable the steam hot air humidifying and heat preserving cover and the boiler to be heatedThe distance of the material-binding surface is 100 mm. Dedusting hot air in a medium temperature range of 325 ℃ of the ring cooler by a deduster, fully mixing the dedusted hot air with steam in a hot air and steam mixing device, humidifying the humidified hot air, and introducing a second steam and hot air humidifying and heat preserving cover to humidify and preserve the sintered charge surface with the thickness of 0-20 m out of a second ignition system; the water content of the hot air-steam mixed gas is controlled to be 0.6%. The mass fraction of the steam in the hot air and steam mixed gas is 18 percent; the steam temperature is controlled at 310 deg.C and the pressure is controlled at 0.8 MPa. And optimally adjusting the negative pressure of air draft to ensure that the sintering materials on the upper layer and the lower layer reach the sintering end point simultaneously to obtain the finished sintering ore.

After the method is applied, the thickness of the sintering material layer is increased from 750mm to 1000mm, and the sintering utilization coefficient is increased from 1.315 t/h.m²The temperature is increased to 1.714 t/(h.m)²) The burning rate of the sintered solid is reduced from 45.2kg/t to 36.4kg/t, and the drum strength of the sintered ore is improved from 79.4 percent to 89.2 percent.

Example 2:

a method for humidifying and insulating the sintered steam of super-thick material layer includes such steps as spraying the mixture of hot air and steam onto the surface of sintered material after the first and the second ignition of double-layer sintering, and humidifying and insulating.

The thickness of the sintering material which is firstly distributed and added on the sintering machine trolley is 580mm, and the sintering material is firstly ignited by a first igniter for air draft sintering; a first steam hot air humidifying and heat preserving cover is arranged above the sintering material surface along the trolley running direction 17m from the first igniter. And adjusting the telescopic joint of the first steam hot air humidifying and heat preserving cover to enable the distance between the first steam hot air humidifying and heat preserving cover and the sintering charge surface to be 100 mm. Dedusting hot air at a low-temperature section of the annular cooler at 260 ℃ by a deduster, fully mixing the dedusted hot air with steam in a hot air and steam mixing device, humidifying the mixture, and introducing a first steam and hot air humidifying and heat preserving cover to humidify and preserve the sintering charge surface with the thickness of 0-17 m out of the first ignition system; the water content of the hot air-steam mixed gas is controlled to be 0.5%. The steam accounts for 8 percent of the mass fraction of the hot air and steam mixed gas; the steam temperature is controlled at 275 deg.C and the pressure is controlled at 0.6 MPa.

When the sintering pallet is moved to the total length of the sintering machineThen, performing secondary material distribution on the surface of the sintered ore which is being sintered, wherein the thickness of the secondary material distribution is 450mm, and performing secondary ignition air draft sintering by a second igniter; a second steam hot air humidifying and heat preserving cover is arranged above the sintering charge level 15m from the second igniter along the running direction of the trolley; dedusting hot air in a medium temperature range of 325 ℃ of the ring cooler by a deduster, fully mixing the dedusted hot air with steam in a hot air and steam mixing device, humidifying the humidified hot air, and introducing a second steam and hot air humidifying and heat preserving cover to humidify and preserve the sintered charge surface with the thickness of 0-15 m out of a second ignition system; the water content of the hot air-steam mixed gas is controlled to be 1.2%. The steam accounts for 22 percent of the mass fraction of the hot air and steam mixed gas; the steam temperature is controlled at 340 deg.C, and the pressure is controlled at 0.7 Mpa. And adjusting the expansion joint of the second steam hot air humidifying and heat preserving cover to ensure that the distance between the steam hot air humidifying and heat preserving cover and the sintering charge surface is 80 mm. And optimally adjusting the negative pressure of air draft to ensure that the sintering materials on the upper layer and the lower layer reach the sintering end point simultaneously to obtain the finished sintering ore.

After the method is applied, the thickness of the sintering material layer is increased from 780mm to 1030mm, and the sintering utilization coefficient is increased from 1.327 t/h.m²The temperature is increased to 1.736 t/(h.m)²) The burning rate of the sintered solid is reduced from 44.3kg/t to 35.4kg/t, and the drum strength of the sintered ore is improved from 79.6 percent to 90.5 percent.