阅读说明：本技术 一种热风烧结系统及方法 (Hot air sintering system and method ) 是由 郑绥旭 栾颖 张志刚 夏克斌 吴天月 黄亚蕾 王忠英 于 2019-09-29 设计创作，主要内容包括：本发明涉及一种热风烧结系统及方法,包括：烧结机和冷却废气管道、循环烟气管道、环境空气管道,将所述的烧结机沿运动方向依次分为烧结前段、烧结中段和烧结后段,在烧结机台车下方设有风箱、风箱支管和与风箱支管相连通的抽风系统,其特征在于：在烧结前段料面上方设有热风罩Ⅰ、在烧结中段料面上方设有热风罩Ⅱ,所述的热风罩Ⅰ通过支管与冷却废气管道相连接,所述的热风罩Ⅱ与若干个气体混合装置相连接,所述的烧结后段对应的风箱支管上设有节流阀。本发明通过优化气体流量、温度、含氧量的组合,向烧结料面不同位置供给不同温度、含氧量的气流,使上、中、下层烧结过程的供热强度趋向一致,提高烧结矿的质量和成品率。(The invention relates to a hot air sintering system and a method, comprising the following steps: sintering machine and cooling exhaust gas pipeline, circulation flue gas pipeline, ambient air pipeline, general the sintering machine divide into sintering anterior segment, sintering middle section and sintering back end along the direction of motion in proper order, be equipped with air bellow, bellows branch pipe and the exhaust system who is linked together with the bellows branch pipe in sintering machine platform truck below, its characterized in that: be equipped with hot-blast cover I, be equipped with hot-blast cover II above sintering middle section charge level in sintering anterior segment charge level top, hot-blast cover I be connected with cooling exhaust gas pipe through the branch pipe, hot-blast cover II be connected with a plurality of gas mixing device, the corresponding bellows branch pipe of sintering back end on be equipped with the choke valve. The invention supplies air flows with different temperatures and oxygen contents to different positions of the sintering charge level by optimizing the combination of the gas flow, the temperature and the oxygen contents, so that the heat supply intensity of the upper, middle and lower layer sintering processes tends to be consistent, and the quality and the yield of the sintering ore are improved.)

1. A hot air sintering system comprising: sintering machine and cooling exhaust gas pipeline, circulation flue gas pipeline, ambient air pipeline, general the sintering machine divide into sintering anterior segment, sintering middle section and sintering back end along the direction of motion in proper order, be equipped with air bellow, bellows branch pipe and the exhaust system who is linked together with the bellows branch pipe in sintering machine platform truck below, its characterized in that: sintering anterior segment charge level top be equipped with hot-blast cover I sintering middle section charge level top be equipped with hot-blast cover II, hot-blast cover I be connected with cooling exhaust gas pipe through the branch pipe, hot-blast cover II be connected with a plurality of gas mixing device, the corresponding bellows branch pipe of sintering back end on be equipped with the choke valve.

2. The hot air sintering system according to claim 1, wherein: a plurality of gas mixing arrangement constitute by house steward, branch pipe I, branch pipe II, governing valve I and governing valve II, house steward one end and II intercommunications of hot-blast cover, the other end communicate with branch pipe I and branch pipe II respectively, branch pipe I be connected with cooling exhaust gas pipeline, branch pipe II and circulation flue gas pipeline or ambient air pipeline intercommunication, governing valve I sets up on branch pipe I, governing valve II sets up on branch pipe II.

3. A hot air sintering method is characterized by comprising the following steps:

S1 Hot air supply before sintering

connecting a hot air hood I with a cooling waste gas pipeline through a branch pipe, supplying cooling waste gas with the temperature of 150-250 ℃ and the oxygen content of about 21% to the sintering front-section charge surface through the hot air hood I, wherein the cooling waste gas comes from a cooling waste gas circulating fan;

S2 middle section sintering hot air supply and air flow control

The hot air hood II is connected with a plurality of gas mixing devices, each gas mixing device consists of a main pipe, a branch pipe I, a branch pipe II, an adjusting valve I and an adjusting valve II, one end of the main pipe is communicated with the hot air hood II, the other end of the main pipe is respectively communicated with the branch pipe I and the branch pipe II, the branch pipe I is connected with a cooling waste gas pipeline, the branch pipe II is communicated with a circulating flue gas pipeline or an ambient air pipeline, the adjusting valve I is arranged on the branch pipe I, the adjusting valve II is arranged on the branch pipe II, the proportion of the mixed cooling waste gas and the circulating flue gas or the ambient air is controlled through the opening degrees of the adjusting valve I and the adjusting valve II, and the oxygen content or the temperature of the mixed gas entering the sintering middle section charge level;

S3 sintering back-end gas flow control

and supplying ambient air to the sintering rear section, and controlling the amount of gas passing through the material layer through a throttle valve arranged on a branch pipe of the bellows.

4. The hot air sintering method according to claim 3, characterized in that: work as the sintering middle section when using the mist of cooling waste gas and circulation flue gas, the circulation flue gas comes from sintering flue gas circulating fan, the proportion of the cooling waste gas of sneaking into and circulation flue gas through the aperture control of governing valve I and governing valve II, along sintering machine direction of motion, the aperture of governing valve I reduces gradually on the gas mixing device, the aperture crescent of governing valve II on the gas mixing device, the cooling waste gas proportion that makes to get into among each gas mixing device reduces gradually, circulation flue gas proportion crescent, the oxygen content of mist reduces gradually.

5. The hot air sintering method according to claim 3, characterized in that: when the sintering middle section used the mist of cooling waste gas and ambient air, the proportion of the cooling waste gas and the ambient air of sneaking into was controlled through the aperture of governing valve I and governing valve II, along sintering machine direction of motion, the aperture of governing valve I on the gas mixing device reduced gradually, and the aperture of governing valve II on the gas mixing device crescent, the cooling waste gas proportion that makes to get into among each gas mixing device reduces gradually, the ambient air proportion crescent, the temperature of mist reduces gradually.

Technical Field

The invention belongs to the technical field of sintering production in ferrous metallurgy industry, and particularly relates to a hot air sintering system and a hot air sintering method

A method.

Background

Sintering is a very important raw material treatment link in the steel production process, and is determined by resource conditions, and raw materials for blast furnace iron making in China mainly comprise sintered ores for a long time. In the sintering production process, the surface layer sintered ore has poor strength due to less heat storage, low sintering temperature and rapid cooling, the specific ratio of the surface layer part is relatively reduced along with the increase of the thickness of the sintered material layer, the return ore rate is reduced, and the yield is improved. Because the thick material layer has more heat storage, the carbon blending amount of the mixture can be properly reduced, and the adverse effect of overhigh temperature of the material layer is avoided. Therefore, the fuel consumption can be saved, the oxidizing atmosphere of the material layer is enhanced, and the reduction of the content of ferrous oxide (FeO) in the sintered ore and the improvement of the reducing performance of the sintered ore are facilitated. At present, the thick material layer sintering technology is generally applied by sintering plants at home and abroad.

In order to improve the quality of the surface layer sinter, a hot air sintering process can be adopted, and the hot air is usually cooling waste gas or circulating flue gas. The temperature of the cooling waste gas is 150-250 ℃, and the oxygen content is about 21%, which means that the hot waste gas generated in the sintering ore cooling process is sent into a hot air hood above the sintering machine by a cooling waste gas circulating fan; the circulating flue gas refers to hot sintering flue gas which is branched from a sintering exhaust system and is sent into a hot air hood above the sintering machine by a sintering flue gas circulating fan. In order to better recycle the residual heat of the hot air (here, cooling exhaust gas or sintering flue gas), a hot air hood is generally arranged at the front section of the sintering machine, so that the hot air is utilized in the upper-layer sintering process. Compared with the ambient air, the hot air with higher temperature enters the material layer and brings certain heat, so that the effect of quenching the surface layer sinter can be weakened, the influence of insufficient heat storage of a part of the upper layer sinter layer can be counteracted, the carbon blending amount of the mixture can be properly reduced, the lower layer overburning is prevented on the basis of improving the quality of the upper layer sinter, and the quality of the sinter is improved.

however, in the sintering production process, the thicknesses of the sintering ore zone, the combustion zone, the drying preheating zone, the over-wet zone and the raw material zone in the sintering material layer are continuously changed from top to bottom, the air permeability of the sintering material layer is changed along with the continuous change of the thicknesses of the sintering ore zone, the combustion zone, the drying preheating zone, the over-wet zone and the raw material zone, the air permeability of the material layer is obviously changed along with the reduction and disappearance of the over-wet zone, the air permeability of the material layer at the rear section (after the over-wet zone disappears) is obviously better than that of the material layer at the front section (before the. In the case of a material bed passing through the same mass flow (or standard flow), the resistance is greater after the gas with higher temperature enters the material bed. Moreover, the higher the temperature of the hot air to be recycled and the larger the air volume, the more the influence on the resistance of the material bed is, and the more obvious the difference of the effective air volume (the air volume passing through the sintering material bed) in the sintering process of the front and rear stages.

According to traditional sintering production mode, the convulsions negative pressure of each bellows is the same basically (the section of igniteing is excluded), when recycle's hot air volume is great, it is the higher hot-blast of temperature to pass through in the anterior segment (before the wet area disappears) sintering bed of material, it is the normal atmospheric temperature air to pass through in the back end (after the wet area disappears) sintering bed of material, cause the actual demand inconsistent with sintering process's that actually passes through the effective amount of wind on sintering bed of material, the effective amount of wind that the anterior segment sintering bed of material passed through is not enough, the effective amount of wind that the back end sintering bed of material passed through is too big.

The effective air quantity determines whether the solid fuel in the sinter layer is fully combusted. When the effective air quantity of the upper layer sintering is insufficient and the material layer has insufficient heat storage, the heat supply amount is low, the generated liquid phase amount is small, the viscosity is low, the probability of the occurrence of loose and porous thin-wall structure sinter is high, the reducibility of the sinter is good, but the strength is low, and the sinter is easy to crush; when the effective air quantity of the lower layer sintering is too large and the heat storage capacity of the material layer is high, the sintering speed is high, the ore forming time is short, the heat supply quantity is excessive, the probability of occurrence of the sintering ore with the macroporous thick wall or the macroporous thin-wall structure is high, the strength of the sintering ore with the macroporous thick wall structure is high, but the reducibility is poor, and the strength and the reducibility of the sintering ore with the macroporous thin-wall structure are both poor.

In order to improve the use effect of the hot air sintering process and strengthen the beneficial effect of the thick material layer sintering process, the whole sintering process needs to be segmented, so that the air supply condition and the air draft condition are differentiated, the actual conditions of the upper layer sintering process, the middle layer sintering process and the lower layer sintering process are respectively adapted, and the quality and the yield of the sintering ore are improved.

Disclosure of Invention

the invention aims to provide a hot air sintering system and a hot air sintering method, which optimize the combination of gas flow, temperature and oxygen content, supply airflow with different properties to different positions of a sintering charge level according to requirements, lead the heat supply intensity of an upper layer sintering process, a middle layer sintering process and a lower layer sintering process to tend to be consistent, and improve the quality and the yield of sintering ores.

the purpose of the invention is realized by the following technical scheme:

the invention relates to a hot air sintering system, which comprises: sintering machine and cooling exhaust gas pipeline, circulation flue gas pipeline, ambient air pipeline, general the sintering machine divide into sintering anterior segment, sintering middle section and sintering back end along the direction of motion in proper order, be equipped with air bellow, bellows branch pipe and the exhaust system who is linked together with the bellows branch pipe in sintering machine platform truck below, its characterized in that: sintering anterior segment charge level top be equipped with hot-blast cover I sintering middle section charge level top be equipped with hot-blast cover II, hot-blast cover I be connected with cooling exhaust gas pipe through the branch pipe, hot-blast cover II be connected with a plurality of gas mixing device, the corresponding bellows branch pipe of sintering back end on be equipped with the choke valve.

a plurality of gas mixing arrangement constitute by house steward, branch pipe I, branch pipe II, governing valve I and governing valve II, house steward one end and II intercommunications of hot-blast cover, the other end communicate with branch pipe I and branch pipe II respectively, branch pipe I be connected with cooling exhaust gas pipeline, branch pipe II and circulation flue gas pipeline or ambient air pipeline intercommunication, governing valve I sets up on branch pipe I, governing valve II sets up on branch pipe II.

the invention relates to a hot air sintering method, which is characterized by comprising the following steps:

S1 Hot air supply before sintering

Connecting a hot air hood I with a cooling waste gas pipeline through a branch pipe, supplying cooling waste gas with the temperature of 150-250 ℃ and the oxygen content of about 21% to the sintering front-section charge surface through the hot air hood I, wherein the cooling waste gas comes from a cooling waste gas circulating fan;

S2 middle section sintering hot air supply and air flow control

The hot air hood II is connected with a plurality of gas mixing devices, each gas mixing device consists of a main pipe, a branch pipe I, a branch pipe II, an adjusting valve I and an adjusting valve II, one end of the main pipe is communicated with the hot air hood II, the other end of the main pipe is respectively communicated with the branch pipe I and the branch pipe II, the branch pipe I is connected with a cooling waste gas pipeline, the branch pipe II is communicated with a circulating flue gas pipeline or an ambient air pipeline, the adjusting valve I is arranged on the branch pipe I, the adjusting valve II is arranged on the branch pipe II, the proportion of the mixed cooling waste gas and the circulating flue gas or the ambient air is controlled through the opening degrees of the adjusting valve I and the adjusting valve II, and the oxygen content or the temperature of the mixed gas entering the sintering middle section charge level;

S3 sintering back-end gas flow control

And supplying ambient air to the sintering rear section, and controlling the gas flow passing through the material layer through a throttle valve arranged on a branch pipe of the air box.

work as the sintering middle section when using the mist of cooling waste gas and circulation flue gas, the circulation flue gas comes from sintering flue gas circulating fan, the proportion of the cooling waste gas of sneaking into and circulation flue gas through the aperture control of governing valve I and governing valve II, along sintering machine direction of motion, the aperture of governing valve I reduces gradually on the gas mixing device, the aperture crescent of governing valve II on the gas mixing device, the cooling waste gas proportion that makes to get into among each gas mixing device reduces gradually, circulation flue gas proportion crescent, the oxygen content of mist reduces gradually.

When the sintering middle section used the mist of cooling waste gas and ambient air, the proportion of the cooling waste gas and the ambient air of sneaking into was controlled through the aperture of governing valve I and governing valve II, along sintering machine direction of motion, the aperture of governing valve I on the gas mixing device reduced gradually, and the aperture of governing valve II on the gas mixing device crescent, the cooling waste gas proportion that makes to get into among each gas mixing device reduces gradually, the ambient air proportion crescent, the temperature of mist reduces gradually.

Compared with the prior art, the invention has the advantages that:

1) The throttle valve arranged on the air box branch pipe is used for controlling the gas flow of the sintering rear section, so that excessive gas can be prevented from passing through the material layer of the sintering rear section, the gas throughput of the sintering front section and the sintering middle section is increased, and favorable conditions are created for the sintering front section and the sintering middle section to absorb more gas (cooling waste gas, circulating flue gas and the like) with higher temperature;

2) the cooling waste gas with high temperature and high oxygen content is more fully utilized in the front sintering stage, the influence of the surface layer sintering ore on the strength due to rapid cooling can be weakened, the heat carried by the waste gas can increase the heat income in the upper layer sintering process, the combustion condition of solid fuel is improved by improving the combustion-supporting air temperature, the heat supply strength in the upper layer sintering process can meet the requirement, and the quality and the yield of the upper layer sintering ore can be improved;

3) The middle section of the sintering corresponds to the middle part of a sintering material layer, the heat storage function of the part is gradually enhanced from top to bottom, gradually-changed mixed gas (the oxygen content is gradually reduced or the temperature is gradually reduced) enters the material layer, the combustion condition of solid fuel in the middle part of the sintering material layer is gradually deteriorated from top to bottom, the heat supply quantity of the solid fuel during combustion and the heat storage quantity are balanced, the heat supply strength of the middle-layer sintering process tends to be stable, and the quality deterioration of the sintering ore of the lower layer due to excessive heat supply can be prevented;

4) The sintering back section utilizes the ambient air, and the gas flow penetrating through the material layer is controlled, so that the influence on the quality of lower-layer sinter due to the over-high sintering speed and over-high heat supply strength can be prevented.

5) By means of the method, the heat supply strength of the upper layer, the middle layer and the lower layer of the sinter bed tends to be consistent, the difference of the sinter ore quantity in the height direction of the whole sinter bed can be reduced, the overall quality of the sinter ore is improved, the ore return rate is reduced, and the method is suitable for the reconstruction of a newly built sintering plant and an original production line and has wide application range.

Drawings

Fig. 1 is a schematic view of embodiment 1 of the present invention.

Fig. 2 is an enlarged sectional view a-a of fig. 1.

Fig. 3 is a schematic view of embodiment 2 of the present invention.

Fig. 4 is an enlarged sectional view B-B of fig. 3.

Detailed description of the preferred embodiments

The invention is further illustrated by the following figures and examples. The drawings are only two embodiments of the invention, and other drawings can be obtained by those skilled in the art without inventive effort.

as shown in fig. 1 to 4, a hot air sintering system of the present invention includes: the sintering machine 1 and a cooling waste gas pipeline 6, a circulating flue gas pipeline 7 and an ambient air pipeline 8 are sequentially divided into a sintering front section 1-1, a sintering middle section 1-2 and a sintering rear section 1-3 along the motion direction, and an air box 9, an air box branch pipe 10 and an air draft system communicated with the air box branch pipe 10 are arranged below a trolley of the sintering machine 1, and the sintering machine is characterized in that: a hot air cover I2 is arranged above the material level of the sintering front section 1-1, a hot air cover II 3 is arranged above the material level of the sintering middle section 1-2, the hot air cover I2 is connected with a cooling waste gas pipeline 6 through a branch pipe 2-1, the hot air cover II 3 is connected with a plurality of gas mixing devices 4, and a throttle valve 5 is arranged on an air box branch pipe 10 corresponding to the sintering rear section 1-3.

The gas mixing devices 4 are composed of a header pipe 4-1, a branch pipe I4-2, a branch pipe II 4-3, a regulating valve I4-4 and a regulating valve II 4-5, one end of the header pipe 4-1 is communicated with a hot air cover II 3, the other end of the header pipe is respectively communicated with the branch pipe I4-2 and the branch pipe II 4-3, the branch pipe I4-2 is connected with a cooling waste gas pipeline 6, the branch pipe II 4-3 is communicated with a circulating flue gas pipeline 7 or an ambient air pipeline 8, the regulating valve I4-4 is arranged on the branch pipe I4-2, and the regulating valve II 4-5 is arranged on the branch pipe II 4-3.