CN214529175U - Roasting system for producing oxidized pellets - Google Patents
Roasting system for producing oxidized pellets Download PDFInfo
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- CN214529175U CN214529175U CN202120633911.3U CN202120633911U CN214529175U CN 214529175 U CN214529175 U CN 214529175U CN 202120633911 U CN202120633911 U CN 202120633911U CN 214529175 U CN214529175 U CN 214529175U
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Abstract
The embodiment of the utility model provides a roasting system for producing oxidized pellets, which comprises a belt roasting system and a high-air-temperature hot air furnace system for providing high-temperature hot air for the belt roasting system; the roasting section of the belt type roasting system is provided with a first high-temperature hot air input pipeline, and the soaking section of the belt type roasting system is provided with a second hot air input pipeline; the high-air-temperature hot blast stove system comprises a heat accumulating type hot blast stove group; the heat accumulating type hot blast stove group is provided with a first high-temperature hot blast output pipeline and a second high-temperature hot blast output pipeline; the first high-temperature hot air output pipeline is connected with the first high-temperature hot air input pipeline; the second high-temperature hot air output pipeline is connected with a second high-temperature hot air input pipeline; a first temperature adjusting device is arranged on the first high-temperature hot air output pipeline; and a second temperature adjusting device is arranged on the second high-temperature hot air output pipeline. The belt type roasting system and the high-air-temperature hot air furnace system for providing high-temperature hot air are separately arranged, and the pellet quality is improved by roasting the pellets by the high-temperature hot air.
Description
Technical Field
The utility model relates to an oxidation pelletizing production field in ferrous metallurgy field, concretely relates to roasting system of production oxidation pelletizing.
Background
The belt type roasting machine is a fine-grained material agglomeration device which is old in history, high in flexibility and wide in application range, and is used for pellet production from the 50 th of the 20 th century. Compared with a sintering process, the pelletizing process is cleaner and more environment-friendly, and meets the requirements of clean production and ultralow emission in the steel industry. Therefore, increasing the pellet usage in the blast furnace burden has been listed by various large iron and steel enterprises in development planning and implementation, and two processes for producing pellets are compared: compared with the grate-grate process, the belt type roasting machine has the advantages of large scale, automatic production, environmental protection and the like. The process characteristics of the straight grate are as follows:
the straight grate roasting machine is mainly composed of blast drying, preheating, roasting and cooling sections. The general roasting temperature is 1100-1300 ℃, and the soaking section has the function of continuously roasting the pellet ore under the condition of slightly low temperature after the pellet ore is roasted at high temperature, so that the pellet ore at the bottom layer is fully solidified. And a cooling section. The pellets are subjected to two stage blast cooling on a belt machine, typically to below 120 ℃. The process flow diagram of the belt type pellet roasting machine is shown in figure 2, and the schematic diagram of the hot air circulation mode of the existing oxidized pellet belt type roasting machine is shown in figure 3. The hot air circulating system is the key of the process of the straight grate type roasting machine, and the straight grate type roasting machine generally has two circulating systems. First, referring to the first drawing of fig. 3, the hot air in the first cooling section (FC) is directly fed to the soaking section (AF), the roasting section (FI) and the preheating section (PH) by residual pressure. Hot air of the second cooling Section (SC) is pressurized and sent to a combustion chamber of the air draft drying section (DD), the preheating section and the roasting section by a fan and is respectively used as drying air and combustion-supporting air. And hot air in the air boxes of the high temperature areas (FI and AF) of the belt type machine is pressurized by a fan and then is sent to an air box of a blast drying section (UD) to be used as a drying medium. The hot air circulating system has the defects that most of air in the air box in the high-temperature area is flue gas, and the air box is in positive pressure in the air blowing and drying section and is easy to escape to pollute the working environment. Therefore, a second hot air circulation system is provided, which is shown in the second figure of the attached figure 3: the hot air in the first cooling section (FC) is directly sent to the soaking section (AF), the roasting section (FI) and the preheating section (PH) by the residual pressure. Hot air in the second cooling Section (SC) is pressurized by a fan and then is delivered to an air draft drying section (UD), and hot air in a high temperature area (FI, AF) air box is pressurized by the fan and then is delivered to an air box in an air blast drying section (DD) to be used as a drying medium. The whole process of the belt type pellet roasting machine, namely drying, preheating, roasting and cooling, is finished on one device, and has the characteristics of simple process, compact arrangement, light tonnage of required devices, high single machine capacity, cyclic utilization of roasting gas, low heat consumption and power consumption and the like, but the defects are obvious.
In implementing the present invention, the applicant has found that there are at least the following problems in the prior art: the belt type roasting machine adopting the process has the advantages that because high-calorific-value fuel (such as coke oven gas which is commonly adopted in large-scale steel enterprises) is required to be used, the content of nitrogen oxides in discharged flue gas exceeds standard, the corresponding environment-friendly equipment investment and operation cost are required to be increased, in addition, the oxidation atmosphere of a pellet roasting area is influenced in the combustion process of the coke oven gas, the selection range of oxidized pellet materials is limited on one hand, the quality of oxidized pellets is influenced on the other hand, and of course, the application of the belt type roasting machine is also limited by the existing process, and for example, the belt type roasting machine can not be used under the condition that the coke oven gas is not available.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a production oxidation pelletizing's baking system, belt baking system edge have set up and have provided the hot-blast high-temperature air heater system of high temperature, thereby separate belt baking system and the hot-blast high-temperature air heater system that provides high temperature, consequently need not burn coke oven gas on belt roaster, need not increase corresponding environmental protection equipment investment and running cost, in addition, the utility model discloses can not change the oxidizing atmosphere in pelletizing calcination district, soaking district, this is favorable to improving oxidation pelletizing quality, also can use belt roaster under the condition that only blast furnace gas.
In order to achieve the above object, in one aspect, the embodiment of the present invention provides a roasting system for producing oxidized pellets, including a belt roasting system and a high-temperature hot-air furnace system for providing high-temperature hot air for the belt roasting system, wherein the high-temperature hot-air furnace system is disposed outside the belt roasting system and is connected to the belt roasting system through a pipeline; wherein:
the belt type roasting system comprises a drying section, a preheating section, a roasting section, a soaking section and a cooling section which are sequentially arranged; the roasting section is provided with a first high-temperature hot air input pipeline, and the soaking section is provided with a second hot air input pipeline;
the high-air-temperature hot blast stove system comprises a heat accumulating type hot blast stove set; the heat accumulating type hot air furnace group is provided with a first high-temperature hot air output pipeline and a second high-temperature hot air output pipeline;
a first high-temperature hot air output pipeline of the heat accumulating type hot air furnace group is connected with a first high-temperature hot air input pipeline of the roasting section; a second high-temperature hot air output pipeline of the heat accumulating type hot air furnace group is connected with a second high-temperature hot air input pipeline of the soaking section;
a first high-temperature hot air output pipeline of the heat accumulating type hot air furnace group is provided with a first adjusting device for adjusting the temperature and the flow of high-temperature hot air in the first high-temperature hot air output pipeline; and a second high-temperature hot air output pipeline of the heat accumulating type hot air furnace group is provided with a second adjusting device for adjusting the temperature and the flow of high-temperature hot air in the second high-temperature hot air output pipeline.
Preferably, the heat accumulating type hot blast stove set comprises at least two heat accumulating type hot blast stoves, each heat accumulating type hot blast stove comprises a heat accumulating chamber, and a heat accumulator for accumulating heat and heating gas is arranged in each heat accumulating chamber; the heat accumulating type hot blast stove is provided with a low-heat-value fuel inlet for receiving low-heat-value fuel and a combustion air inlet; the heat accumulating type hot blast stove is also provided with a gas input pipeline for conveying gas into the heat accumulating chamber; the heat accumulating type hot blast stove heats a heat accumulator of the heat accumulating chamber through smoke generated by burning low-heat-value fuel, and the heated heat accumulator heats gas filled in the heat accumulator to form high-temperature hot blast;
the heat accumulator is provided with a high-temperature hot air outlet; the high-temperature hot air outlet is connected with the high-temperature hot air output pipeline.
Preferably, the regenerative hot blast stove set comprises three regenerative hot blast stoves.
Preferably, the regenerative hot blast stove group comprises four regenerative hot blast stoves.
Preferably, the heat accumulating type hot blast stove set is provided with a smoke discharge channel for discharging smoke generated by burning low-heating-value fuel;
the high-air-temperature hot blast stove system also comprises a high-temperature heat exchanger, and the high-temperature heat exchanger is connected with a flue gas discharge channel of the heat accumulating type hot blast stove set;
the high-temperature heat exchanger comprises a combustion-supporting air high-temperature heat exchanger, the combustion-supporting air high-temperature heat exchanger is provided with a smoke inlet and a combustion-supporting air outlet, the smoke inlet of the combustion-supporting air high-temperature heat exchanger is connected to a smoke discharge channel of the heat accumulating type hot blast furnace set, and the combustion-supporting air outlet of the combustion-supporting air high-temperature heat exchanger is connected to the heat accumulating type hot blast furnace set;
the high-air-temperature hot air furnace system further comprises a combustion-supporting fan, the combustion-supporting fan is used for preheating combustion-supporting air through the heat-accumulating hot air furnace flue gas, and the combustion-supporting air is subjected to high-temperature heat exchange by the combustion-supporting fan.
Preferably, the high-temperature heat exchanger further comprises a fuel heat exchanger connected to the combustion air high-temperature heat exchanger through a pipeline;
the combustion-supporting air high-temperature heat exchanger is provided with a flue gas discharge channel; the fuel heat exchanger is connected with a flue gas discharge channel of the combustion air high-temperature heat exchanger;
the high-air-temperature hot blast stove system further comprises a fuel conveying pipeline for providing low-heat-value fuel for the heat accumulating type hot blast stove set, and the fuel conveying pipeline conveys the low-heat-value fuel to a fuel heat exchanger for preheating the low-heat-value fuel.
Preferably, the heat storage type hot blast stove further comprises an air draft device, wherein the air draft device is provided with an air inlet and an air outlet, the air inlet of the air draft device is connected with the cooling section, and the air outlet of the air draft device is connected with the heat storage type hot blast stove group; the air draft device pumps part of the cooling hot air generated by the cooling section into a heat storage chamber of the heat storage type hot blast stove; the heat accumulating type hot blast stove heats a heat accumulator in the heat accumulating chamber through smoke generated by burning low-heat-value fuel, and then the high-temperature heat accumulator heats the part of cooling hot air to form high-temperature hot air.
Preferably, the low heating value fuel is a low heating value gas fuel.
Preferably, the low heating value gas fuel comprises blast furnace gas.
The technical scheme has the following beneficial effects: the belt type roasting system is not provided with a fuel burner, namely, the pellets are roasted by adopting high-temperature hot air provided by a high-air-temperature hot air furnace system instead of the mixed flue gas of high-temperature flue gas and cooling hot air, so that the oxidizing atmosphere in a roasting area is improved, and the pellet quality is improved. The pellet is roasted by adopting high-air-temperature air, so that the selection range of pellet materials is expanded, and the cost of the pellet materials is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a roasting system for producing oxidized pellets according to an embodiment of the present invention;
FIG. 2 is a process flow diagram of a conventional belt type roasting machine system for oxidized pellets;
FIG. 3 is a schematic view of a hot air circulation mode of a conventional belt type roasting machine for oxidized pellets.
The reference numerals are represented as:
110. a drying section; 120. a preheating section; 130. a roasting section; 140. a soaking section; 150. a cooling section; 200. a heat accumulating type hot blast stove set; 210. a combustion air high temperature heat exchanger; 220. a fuel heat exchanger;
100. oxidizing the kiln body of the pellet belt type roasting system.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
As shown in fig. 1, in combination with the embodiment of the present invention, a roasting system for producing oxidized pellets is provided, which includes a belt roasting system and a high-temperature hot-air furnace system for providing high-temperature hot air for the belt roasting system, wherein the high-temperature hot-air furnace system is disposed outside the belt roasting system, and the high-temperature hot-air furnace system is connected to the belt roasting system through a pipeline; other associated auxiliary equipment is also included, such as: supporting equipment such as a trolley and a fan, electric appliance and instrument control devices, a dust removal device and the like (not shown in the schematic diagram). Compared with the conventional oxidized pellet belt type roasting machine, the belt type roasting system cancels a high-calorific-value fuel burner. The belt type roasting system comprises a drying section 110, a preheating section 120, a roasting section 130, a soaking section 140 and a cooling section 150 which are sequentially arranged, and a kiln body 100 of the oxidized pellet belt type roasting system is formed by the drying section 110, the preheating section 120, the roasting section 130, the soaking section 140 and the cooling section 150; the roasting section 130 has a first high temperature hot air input duct, and the soaking section 140 has a second hot air input duct.
The pellets are conveyed to the drying section 110 and dried in the drying section 110, the dried pellets are conveyed to the preheating section 120 and preheated in the preheating section 120, the preheated pellets sequentially enter the roasting section 130 and the soaking section 140 for roasting, and the pellets enter the cooling section 150 for cooling after the roasting is finished.
The high blast temperature hot blast stove system includes a regenerative hot blast stove group 200 for supplying required high temperature hot blast to the roasting section 130 and the soaking section 140. The heat accumulating type hot air furnace group 200 is provided with a first high-temperature hot air output pipeline and a second high-temperature hot air output pipeline; a first high-temperature hot air output pipeline of the heat accumulating type hot air furnace group 200 is connected with a first high-temperature hot air input pipeline of the roasting section 130; the second high-temperature hot air output pipeline of the regenerative hot air furnace group 200 is connected to the second high-temperature hot air input pipeline of the soaking section 140.
In the process of roasting by using the high-temperature hot air provided by the heat accumulating type hot air furnace set 200 in the roasting section 130, the oxidation atmosphere in the roasting area is not affected, so that the high-temperature hot air can form a constant-temperature oxidation atmosphere (the oxidation atmosphere is prevented from changing constantly) in the roasting section 130, the dried and preheated pellets are roasted in the constant-temperature oxidation atmosphere, and the quality of the generated oxidized pellets is higher. The constant temperature oxidation atmosphere is a preset temperature range of high temperature air which satisfies the heat required by the pellet to be roasted in the roasting section 130.
After the pellet reaches the preset level of the roasting section, the pellet is conveyed to the soaking section 140, in the process of conveying the high-temperature hot air of the heat accumulating type hot air furnace set 200 to the soaking section 140 to continuously roast the pellet, the oxidizing atmosphere in the pellet roasting area cannot be influenced, so the heat accumulating type hot air furnace set 200 can form a constant-temperature oxidizing atmosphere (the oxidizing atmosphere is prevented from continuously changing) in the soaking section 140 from the high-temperature hot air input pipeline of the soaking section 140, the pellet is continuously roasted in the constant-temperature oxidizing atmosphere to reach the preset level, and the quality of the oxidized pellet generated at the moment can be higher. Wherein, the constant temperature oxidation atmosphere is the preset temperature range of high temperature air which meets the heat required by the roasting of the pellets in the soaking section 140.
According to the process requirements, the pellet roasting parameters in the roasting section 130 and the soaking section 140 are different, so that an adjusting device (not shown in the schematic diagram) can be arranged on the hot air pipelines respectively input to the roasting section 130 and the soaking section 140 in the heat accumulating type hot air furnace, a first adjusting device for adjusting the temperature and the flow of the high-temperature hot air in the first high-temperature hot air output pipeline of the heat accumulating type hot air furnace group 200 is arranged on the first high-temperature hot air output pipeline, and the temperature and the flow of the high-temperature hot air are reasonably adjusted according to the working conditions so as to be sent to the roasting section 130; a second high-temperature hot air output pipeline of the heat accumulating type hot air furnace group 200 is provided with a second adjusting device for adjusting the temperature and the flow of the high-temperature hot air therein, and the temperature and the flow of the high-temperature hot air are reasonably adjusted according to the working condition so as to be sent to the soaking section 140. The high-temperature hot air conveyed from the heat accumulating type hot air furnace set 200 is reasonably distributed, so that the hot air can supply heat to the roasting section 130 and the soaking section 140 according to the process requirements, the complete roasting of the pellets is completed in the optimal oxidation atmosphere, and the quality of the oxidized pellets is improved (the strength of the pellets is improved).
And conveying the oxidized pellets roasted in the soaking section 140 to the cooling section 150, and blowing cooling air into the cooling section 150 to cool the roasted oxidized pellets to obtain finished oxidized pellets.
The fuel nozzle of conventional belt roasting machine has been cancelled, the utility model discloses a do not have the fuel nozzle among the belt roasting system, but set up on the belt roasting system edge and provide the hot-blast high-temperature hot-blast furnace system of high temperature, replace high temperature flue gas (with cooling hot-blast) mixed wind calcination technology with the hot-blast calcination pelletizing technology of high temperature to the calcination oxidizing atmosphere of calcination section and soaking section has been improved, the pellet quality has been improved. Meanwhile, the restriction standard of the pellet material is reduced, so that the cost of the pellet material can be reduced.
Preferably, the regenerative hot blast heater group 200 includes at least two regenerative hot blast heaters, such as 2, 3, and 4, preferably 3 or 4 regenerative hot blast heaters, and the regenerative hot blast heaters include a regenerative chamber, and a regenerator for storing heat and heating gas is disposed in the regenerative chamber; the heat accumulating type hot blast stove is provided with a low-heat-value fuel inlet and a combustion air inlet, low-heat-value fuel enters the heat accumulating type hot blast stove through the low-heat-value fuel inlet to be combusted, the combustion air inlet is conveyed into the heat accumulating type hot blast stove, and the low-heat-value fuel and the combustion air are mixed and combusted in the heat accumulating type hot blast stove to generate hot flue gas; the heat accumulating type hot blast stove is also provided with a gas input pipeline for conveying gas into the heat accumulating chamber. Then the flue gas generated by burning the low-heat value fuel heats the heat accumulator of the heat accumulation chamber, and then the high-temperature heat accumulator heats the gas (which can be air) filled in the heat accumulation chamber to the temperature which can meet the use requirement of the pellet roasting process (the energy loss on a transmission path needs to be considered), namely high-temperature hot air is formed. The heat accumulating type hot blast stove is also provided with a high-temperature hot blast output pipeline for respectively conveying the generated high-temperature hot blast to the roasting section 130 and the soaking section 140.
Wherein, the main work flow about heat accumulation formula hot-blast furnace is: (1) and (3) a furnace burning period: low-heat value fuel and combustion air are combusted, the generated hot flue gas heats the heat accumulator in the heat accumulator, and then the air supply period of (2) is switched to: after entering, the gas passes through the heat accumulator in the heat accumulation chamber, is heated by the high-temperature heat accumulator and then is discharged out of the heat accumulation type hot blast stove, and the gas is switched to a burning period (1) after the heat exchange of the heat accumulator is finished and the temperature of the heat accumulator is reduced. Therefore, the burning and air supply of each heat accumulating type hot blast stove are intermittent, one hot blast stove can not continuously supply air, at least 2 hot blast stoves work simultaneously, and the other hot blast stove supplies air when one is burned. Furthermore, in order to supply air at a high enough temperature, three heat accumulating type hot blast stoves are adopted, and two hot blast stoves burn the stove and one hot blast stove supplies air, so that the stove burning time can be prolonged, the heat accumulator is guaranteed to store enough heat, and the air temperature is favorably improved.
Preferably, the heat accumulating type hot blast stove set 200 is provided with a smoke discharge channel for discharging the smoke generated by burning the low-heating-value fuel after heat exchange;
the high-air-temperature hot blast stove system further comprises a high-temperature heat exchanger, and the high-temperature heat exchanger is connected to a flue gas discharge channel of the heat accumulating type hot blast stove set 200;
the high-temperature heat exchanger comprises a combustion-supporting air high-temperature heat exchanger 210, the combustion-supporting air high-temperature heat exchanger 210 is provided with a smoke inlet and a combustion-supporting air outlet, the smoke inlet of the combustion-supporting air high-temperature heat exchanger 210 is connected to a smoke discharge channel of the heat accumulating type hot blast furnace set 200, and the combustion-supporting air outlet of the combustion-supporting air high-temperature heat exchanger 210 is connected to the heat accumulating type hot blast furnace set 200; the high air temperature hot blast stove system further comprises a combustion fan, wherein the combustion fan inputs combustion air into a combustion air high temperature heat exchanger 210 for preheating the combustion air; the combustion-supporting fan inputs combustion-supporting air into the combustion-supporting air high-temperature heat exchanger 210 for preheating the combustion-supporting air, the combustion-supporting air is preheated by flue gas from the smoke exhaust channel of the regenerative hot blast stove in the combustion-supporting air high-temperature heat exchanger 210, and the preheated combustion-supporting air is discharged into the regenerative hot blast stove group 200 through the combustion-supporting air outlet. The combustion temperature of the low-heating-value fuel is improved, and the fuel consumption is reduced.
Preferably, the high temperature heat exchanger further comprises a fuel heat exchanger 220 connected to the combustion air high temperature heat exchanger 210 through a pipe; the combustion air high-temperature heat exchanger 210 is provided with a flue gas discharge channel; the fuel heat exchanger 220 is connected to a flue gas discharge passage of the combustion air high temperature heat exchanger 210. The high-air-temperature hot-blast stove system further comprises a fuel supply conveying pipeline for providing low-heat-value fuel for the heat accumulating type hot-blast stove set 200, the fuel conveying pipeline conveys the low-heat-value fuel to a fuel heat exchanger 220 for preheating the low-heat-value fuel, the low-heat-value fuel is preheated through the waste heat of the flue gas discharged from a combustion air high-temperature heat exchanger 210 in the fuel heat exchanger 220, the preheated low-heat-value fuel is discharged into the heat accumulating type hot-blast stove set 200 for combustion to generate hot flue gas, and the fuel consumption is reduced. And then discharging flue gas generated by combustion of the heat-exchanged low-calorific-value fuel to a chimney.
That is, the high-temperature heat exchanger includes a combustion air high-temperature heat exchanger 210 and a fuel heat exchanger 220, the flue gas generated by the heat accumulating type hot air furnace set 200 is used for preheating the low-heat value fuel and the combustion air, the preheated low-heat value fuel and the preheated combustion air enter the heat accumulating type hot air furnace set 200 for combustion, and the waste heat of the flue gas generated by the heat accumulating type hot air furnace set 200 is fully utilized, so that the effect of reducing the fuel consumption of the hot air furnace is achieved, and the production cost is reduced.
To sum up, the low-calorific-value fuel and the combustion air pass through the combustion air high-temperature heat exchanger 210 and the fuel heat exchanger 220, and enter the regenerative hot air furnace group 200 to burn, so that the effect of reducing the fuel consumption of the hot air furnace is achieved, and the production cost is reduced.
In contrast, in the prior art, a fuel with a high calorific value (such as coke oven gas) is used, the combustion temperature is high, and NOx is generated, so that a flue gas denitration device is required, the environmental protection cost is increased, and the combustion flue gas affects the local oxidation atmosphere.
Preferably, the heat accumulating type hot blast stove comprises an air extracting device, wherein the air extracting device is provided with an air inlet and an air outlet, the air inlet of the air extracting device is connected with a cooling hot blast output pipeline of the cooling section 150, and the air outlet of the air extracting device is connected with the heat accumulating type hot blast stove group 200; the air draft device sucks part of the cooling hot wind generated by the cooling section 150 into the heat accumulating type hot wind furnace set 200; the heat accumulating type hot blast stove heats a heat accumulator in the heat accumulating chamber through smoke generated by burning low-heat-value fuel, and the high-temperature heat accumulator heats the part of cooling hot air to form high-temperature hot air. That is, the heat accumulating type hot air furnace set 200 continuously heats part of the cooling hot air to the temperature (for example, 1200 ℃ to 1300 ℃ or 1100 ℃ to 1300 ℃) required by the process to obtain high-temperature air hot air (high-temperature hot air), and then returns the high-temperature hot air to the roasting section and the soaking section of the belt roasting system, the waste air (cooling hot air) after roasting participates in hot air circulation, and the hot air circulation is consistent with the hot air circulation process of the existing belt roasting machine. Therefore, the utility model discloses can utilize conventional belt type roasting machine hot air circulating system, reduce the investment that current oxidation pelletizing belt type roasting machine upgrades and reforms transform.
Preferably, the low heating value fuel is a low heating value gas fuel; the low heating value gas fuel comprises blast furnace gas. The method uses the fuel with lower calorific value (such as blast furnace gas from a pipe network) and utilizes a belt type roasting system to produce the oxidized pellets, thereby not only substantially replacing the coke oven gas with high price or other fuels with high calorific value adopted in the prior art, but also reducing the operating cost of the fuel. The combustion of the blast furnace gas can realize that the NOx emission reaches the standard and meets the requirement of environmental protection, thereby saving the investment of combustion flue gas denitration equipment and the denitration operation cost of fuels with high nitrogen content such as coke oven gas and the like; the utility model discloses cancelled the calcination method of high temperature combustion flue gas mixed air, improved pelletizing calcination oxidizing atmosphere, realized calcination constant temperature atmosphere, avoided the raw materials kind restriction of fuel, further reduced the oxidation pelletizing cost.
In conclusion, the heat accumulating type hot blast furnace set 200 is utilized to roast the pellets by high-temperature hot blast on the premise of ensuring environmental protection and reaching standards, so that the existing oxidized pellet belt type roasting machine process can be fully utilized, the system of the utility model is reformed on the basis of the process, conditions are provided for the process design of the novel oxidized pellet belt type roasting system, the oxidized pellet raw materials are further expanded, and the application range of the belt type roasting system is expanded. Particularly, because the blast furnace gas is adopted to replace the coke oven gas, a denitration treatment device does not need to be configured for the belt type roasting machine, and the investment of environment-friendly equipment and the environment-friendly operation cost are saved.
In summary, the hot air circulation of the belt type roasting system is as follows: cooling air from the cooling fan is blown into the cooling section 150 from the lower portion of the cooling section; the low-temperature cooling air after cooling the pellets is pumped to the drying section 110, blown into the drying section 110 from the lower part of the drying section 110, and exhausted after being pumped out after drying. Part of the cooling hot air crosses the roasting section 130 and the soaking section 140 and enters the preheating section 120; the other part of the cooling hot air is pumped out from the cooling section 150 and enters the high-air-temperature hot air furnace system to be heated into high-temperature hot air to return to the roasting section 130 and the soaking section 140, the roasted waste air is pumped from the lower part of the trolley to the front end of the preheating section 120 to blow, dry and preheat the pellets from the upper part of the trolley, and the waste air is directly discharged.
The difference from the hot air circulating system of the conventional straight grate type roasting machine is that a part of the cooling hot air originally entering the roasting section 130 and the soaking section 140 is extracted in the present application, and is heated by the regenerative hot air furnace group 200 and then returns to the roasting section 130 and the soaking section 140 in equal quantity, although the roasting mode is changed, the heat quantity and the total air quantity are not changed.
The embodiment of the utility model is combined, a roasting method for producing oxidized pellets is provided, a belt type roasting system and a high-air temperature hot blast stove system connected with the belt type roasting system are adopted to jointly complete the roasting of the pellets; the belt type roasting system comprises a drying section 110, a preheating section 120, a roasting section 130, a soaking section 140 and a cooling section 150 which are sequentially arranged; the high-air-temperature hot air furnace system is arranged outside the belt type roasting system and provides high-temperature hot air for roasting the pellets for the belt type roasting system;
the roasting method for producing the oxidized pellets comprises the following steps:
the pellets are transferred to the drying section 110 to be dried in the drying section 110, and the dried pellets are transferred to the preheating section 120, where the pellets are preheated in the preheating section 120;
the high-air-temperature hot-blast stove system is provided with a heat accumulating type hot-blast stove set 200, and high-temperature hot air is generated through the heat accumulating type hot-blast stove set 200;
the generated high-temperature hot air is conveyed to a first high-temperature hot air input pipeline of the roasting section 130 through the first high-temperature hot air output pipeline, and the temperature and the flow of the high-temperature hot air in the high-temperature hot air input pipeline are regulated into a first temperature and flow range required by pellet roasting through a first regulating device arranged on the first high-temperature hot air output pipeline in the process that the high-temperature hot air passes through the first high-temperature hot air output pipeline; and the number of the first and second groups,
the generated high-temperature hot air is conveyed to a second high-temperature hot air input pipeline of the soaking section 140 through the second high-temperature hot air output pipeline, and the temperature and the flow of the high-temperature hot air in the high-temperature hot air input pipeline are regulated into a second temperature and flow range required by pellet roasting through a second regulating device arranged on the second high-temperature hot air output pipeline in the process that the high-temperature hot air passes through the second high-temperature hot air output pipeline; the preheated pellets are conveyed to a roasting section 130, and the pellets are roasted by high-temperature hot air entering from a first high-temperature hot air input pipeline to reach a preset level;
the pellets roasted in the roasting section 130 are conveyed to the soaking section 140, and the full-thickness roasting strengthening is performed on the pellets through the second high-temperature hot air input pipeline, so that the quality requirement set for the pellet roasting is met;
the oxidized pellets roasted in the soaking section 140 are conveyed to the cooling section 150, and cooling air is blown to cool the oxidized pellets, so that finished oxidized pellets are obtained.
Preferably, the method further comprises the following steps:
the heat accumulating type hot blast stove set 200 is at least provided with two heat accumulating type hot blast stoves, low-heat-value fuel is input into the heat accumulating type hot blast stoves from a low-heat-value fuel inlet of the heat accumulating type hot blast stoves, and the low-heat-value fuel is combusted in the heat accumulating type hot blast stoves to generate high-temperature flue gas;
each heat accumulating type hot blast stove is provided with a heat accumulating chamber, a heat accumulator for storing heat accumulating quantity and heating gas is arranged in the heat accumulating chamber, and gas is conveyed into the heat accumulating chamber through a gas input pipeline arranged in the heat accumulating type hot blast stove;
inputting combustion air into the heat accumulating type hot blast stove through a combustion air inlet, and inputting low-calorific-value fuel into the heat accumulating type hot blast stove through a low-calorific-value fuel inlet;
the high-temperature flue gas generated by mixing and burning combustion-supporting air and low-calorific-value fuel heats the heat accumulator in the heat accumulation chamber, and then the gas input into the heat accumulation chamber is heated by the high-temperature heat accumulator to form high-temperature hot air;
the generated high-temperature hot air is conveyed to a first high-temperature hot air output pipeline through a high-temperature hot air outlet arranged at the upper part of the regenerative chamber; and the number of the first and second groups,
and the generated high-temperature hot air is conveyed to a second high-temperature hot air output pipeline through a high-temperature hot air outlet arranged on the upper body of the storage chamber.
Preferably, the method further comprises the following steps:
the heat accumulating type hot blast stove set 200 is provided with a smoke discharge passage through which smoke generated by burning low-calorific-value fuel is discharged;
the high-air-temperature hot blast stove system is provided with a high-temperature heat exchanger, and the high-temperature heat exchanger is connected to a smoke discharge channel of the heat accumulating type hot blast stove set 200;
the high-temperature heat exchanger is provided with a combustion air high-temperature heat exchanger 210, and a smoke inlet of the combustion air high-temperature heat exchanger 210 is connected to a smoke discharge channel of the regenerative hot blast heater unit 200;
connecting a combustion-supporting fan to the combustion-supporting air high-temperature heat exchanger 210, inputting combustion-supporting air into the combustion-supporting air high-temperature heat exchanger 210 for preheating combustion-supporting air by the combustion-supporting fan, preheating the combustion-supporting air by using the waste heat of flue gas discharged after heat exchange from the heat accumulating type hot blast stove in the combustion-supporting air high-temperature heat exchanger 210, and discharging the preheated combustion-supporting air into the heat accumulating type hot blast stove set 200 through a combustion-supporting air outlet of the heat accumulating type hot blast stove set;
the high-temperature heat exchanger is provided with a fuel heat exchanger 220, the fuel heat exchanger 220 is connected to a flue gas discharge channel of the combustion air high-temperature heat exchanger 210, and the flue gas discharge channel of the combustion air high-temperature heat exchanger 210 is used for discharging flue gas after heat exchange;
connecting a fuel transfer pipe for supplying a low heating value fuel to the regenerative hot blast heater group 200 to a fuel heat exchanger 220; the fuel conveying pipeline conveys the low-heat-value fuel to the fuel heat exchanger 220, and the low-heat-value fuel is preheated by the waste heat of the flue gas in the fuel heat exchanger 220;
and delivers the preheated low calorie fuel to be discharged into the regenerative hot blast heater group 200.
Preferably, the method further comprises the following steps:
arranging an air draft device, connecting an air inlet of the air draft device with the cooling section 150, and connecting an air outlet of the air draft device with the heat accumulating type hot blast stove set 200;
part of the cooling hot air generated by the cooling section 150 is pumped into an air inlet of the cooling hot air pumping device, and the part of the cooling hot air is pumped into a heat storage chamber of the heat storage type hot air furnace from an air outlet of the cooling hot air pumping device;
the heat accumulator in the heat accumulation chamber is heated by smoke generated by burning low-heat-value fuel by the heat accumulation type hot blast stove, and the high-temperature heat accumulator heats the part of cooling hot air to form high-temperature hot air.
Preferably, the method further comprises the following steps:
the method comprises the following steps of taking low-heat-value gas fuel as fuel of a heat accumulating type hot blast stove, combusting the low-heat-value gas fuel in the heat accumulating type hot blast stove, and generating high-temperature flue gas by combusting the low-heat-value gas fuel; wherein the low heating value gas fuel comprises blast furnace gas.
In summary, the blast furnace gas and the combustion air enter the heat accumulating type hot blast furnace unit 200 for combustion after being preheated, the generated high-temperature flue gas is used for heating the heat accumulator, and the cooled combustion flue gas is used for preheating the blast furnace gas and the combustion air and then is directly discharged. Part of the cooling hot air from the belt type roasting system enters the heat accumulating type hot air furnace set 200, is heated by the high-temperature heat accumulator and then returns to the roasting section and the soaking section of the belt type roasting system through the high-temperature hot air pipeline, and is used for roasting the pellets in the roasting section and the soaking section. The high-temperature heat exchanger preheats blast furnace gas and combustion air by using the waste heat of flue gas discharged by the heat accumulating type hot blast furnace, and discharges the preheated gas and the combustion air after cooling. The high-temperature heat exchanger can be a heat accumulating type heat exchanger or a direct heat exchanger (a dividing wall type heat exchanger), and the dividing wall type heat exchanger is generally adopted for gas preheating.
The utility model discloses in, cancel high calorific value fuel nozzle, use that does not have flame, constancy of temperature and adjustable high temperature air is hot-blast (high temperature is hot-blast) to the pellet calcination, consequently can improve the oxidizing atmosphere of calcination section and soaking section to reinforcing pellet intensity.
The utility model discloses in, use do not have flame, can carry out the calcination to the pelletizing according to the high temperature air hot-blast that the technological requirement set for, improve the oxidizing atmosphere of calcination section and soaking section, expanded oxidation pelletizing raw materials optional range, be suitable for the multiple pelletizing raw materials of calcination, be favorable to reducing the pelletizing cost. The utility model discloses in, can set for the hot-blast temperature of high temperature air according to pelletizing calcination technology requirement, provide the best calcination oxidizing atmosphere, be suitable for the multiple pellet raw materials of calcination, be not limited to and use current belt roaster hot air circulating system, also be applicable to various novel belt roaster processes.
In the utility model discloses in, can use single low heat value blast furnace gas as fuel, compare and adopt coke oven gas to do fuel, the hot-blast furnace adopts low-nitrogen combustion technology, consequently can guarantee that nitrogen oxide discharges up to standard, need not to set up for belt roasting system and takes off a round pin facility, has reduced the environmental protection cost, has reduced the fuel cost simultaneously.
In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, the invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. To those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A roasting system for producing oxidized pellets is characterized by comprising a belt roasting system and a high-air-temperature hot air furnace system for providing high-temperature hot air for the belt roasting system, wherein the high-air-temperature hot air furnace system is arranged outside the belt roasting system and is connected with the belt roasting system through a pipeline; wherein:
the belt type roasting system comprises a drying section (110), a preheating section (120), a roasting section (130), a soaking section (140) and a cooling section (150) which are arranged in sequence; wherein the roasting section (130) is provided with a first high-temperature hot air input pipeline, and the soaking section (140) is provided with a second hot air input pipeline;
the high-air-temperature hot blast stove system comprises a heat accumulating type hot blast stove set (200); the heat accumulating type hot air furnace group (200) is provided with a first high-temperature hot air output pipeline and a second high-temperature hot air output pipeline;
a first high-temperature hot air output pipeline of the heat accumulating type hot air furnace set (200) is connected with a first high-temperature hot air input pipeline of the roasting section (130); a second high-temperature hot air output pipeline of the heat accumulating type hot air furnace set (200) is connected with a second high-temperature hot air input pipeline of the soaking section (140);
a first high-temperature hot air output pipeline of the heat accumulating type hot air furnace set (200) is provided with a first adjusting device for adjusting the temperature and the flow of high-temperature hot air in the first high-temperature hot air output pipeline; and a second high-temperature hot air output pipeline of the heat accumulating type hot air furnace set (200) is provided with a second adjusting device for adjusting the temperature and the flow of the high-temperature hot air in the second high-temperature hot air output pipeline.
2. The roasting system for producing oxidized pellets according to claim 1, wherein the regenerative hot-blast furnace set (200) comprises at least two regenerative hot-blast furnaces, the regenerative hot-blast furnaces comprise regenerative chambers, and the regenerative chambers are internally provided with heat accumulators for storing heat and heating gas; the heat accumulating type hot blast stove is provided with a low-heat-value fuel inlet for receiving low-heat-value fuel and a combustion air inlet; the heat accumulating type hot blast stove is also provided with a gas input pipeline for conveying gas into the heat accumulating chamber; the heat accumulating type hot blast stove heats a heat accumulator of the heat accumulating chamber through smoke generated by mixing and burning low-calorific-value fuel and combustion-supporting air, and the heated heat accumulator heats gas filled in the heat accumulator to form high-temperature hot air;
the heat accumulator is provided with a high-temperature hot air outlet; the high-temperature hot air outlet is connected with the high-temperature hot air output pipeline.
3. The roasting system for producing oxidized pellets according to claim 2, wherein the regenerative hot blast furnace set (200) comprises three regenerative hot blast furnaces.
4. The roasting system for producing oxidized pellets according to claim 2, wherein the regenerative hot blast furnace set (200) comprises four regenerative hot blast furnaces.
5. The roasting system for producing oxidized pellets according to claim 2, wherein the regenerative hot blast furnace set (200) is provided with a flue gas discharge passage for discharging flue gas generated by combustion of low calorific value fuel after heat exchange;
the high-air-temperature hot blast stove system also comprises a high-temperature heat exchanger, and the high-temperature heat exchanger is connected with a flue gas discharge channel of the heat accumulating type hot blast stove set (200);
the high-temperature heat exchanger comprises a combustion-supporting air high-temperature heat exchanger (210), the combustion-supporting air high-temperature heat exchanger (210) is provided with a smoke inlet and a combustion-supporting air outlet, the smoke inlet of the combustion-supporting air high-temperature heat exchanger (210) is connected to a smoke discharge channel of the heat accumulating type hot blast stove set (200), and the combustion-supporting air outlet of the combustion-supporting air high-temperature heat exchanger (210) is connected to the heat accumulating type hot blast stove set (200);
the high-air-temperature hot air furnace system further comprises a combustion-supporting fan, wherein the combustion-supporting fan preheats combustion-supporting air by the heat accumulating type hot air furnace flue gas through a combustion-supporting air high-temperature heat exchanger (210).
6. The roasting system for producing oxidized pellets of claim 5, wherein:
the high-temperature heat exchanger also comprises a fuel heat exchanger (220) connected with the combustion air high-temperature heat exchanger (210) through a pipeline;
the combustion air high-temperature heat exchanger (210) is provided with a flue gas discharge channel; the fuel heat exchanger (220) is connected to a flue gas discharge channel of the combustion air high-temperature heat exchanger (210);
the high blast temperature hot blast stove system further comprises a fuel delivery pipeline for providing low heating value fuel for the heat accumulating type hot blast stove set (200), and the fuel delivery pipeline delivers the low heating value fuel to a fuel heat exchanger (220) for preheating the low heating value fuel.
7. The roasting system for producing the oxidized pellets according to claim 2, further comprising an air draft device, wherein the air draft device is provided with an air inlet and an air outlet, the air inlet of the air draft device is connected with the cooling section (150), and the air outlet of the air draft device is connected with the heat accumulating type hot blast furnace set (200); the air draft device pumps part of the cooling hot air generated by the cooling section (150) into a heat storage chamber of the heat storage type hot blast stove; the heat accumulating type hot blast stove heats a heat accumulator in the heat accumulating chamber through smoke generated by burning low-heat-value fuel, and then the high-temperature heat accumulator heats the part of cooling hot air to form high-temperature hot air.
8. The roasting system for producing oxidized pellets of claim 2, wherein the low calorific value fuel is a low calorific value gas fuel.
9. The roasting system for producing oxidized pellets of claim 8, wherein the low heating value gas fuel comprises blast furnace gas.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113061717A (en) * | 2021-03-29 | 2021-07-02 | 北京卡卢金热风炉技术有限公司 | Roasting system and method for producing oxidized pellets |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113061717A (en) * | 2021-03-29 | 2021-07-02 | 北京卡卢金热风炉技术有限公司 | Roasting system and method for producing oxidized pellets |
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