Microwave-inductive coupling heating pure hydrogen reduction rotary kiln ironmaking system

Abstract

The utility model discloses a microwave-inductive coupling heating pure hydrogen reduction rotary kiln ironmaking system, and belongs to the technical field of reduced iron smelting. The technical problem that furnace burden ring formation in a traditional rotary kiln needs to be cleared at regular time after production halt is solved. The system comprises a rotary kiln reduction device body, a first driving device and a second driving device, the rotary kiln reduction device body comprises a rotary kiln body and an independent rotating structure; the first driving device is arranged outside the rotary kiln body and is in transmission connection with the rotary kiln body; the independent rotating structure comprises a rotating shaft and special-shaped rotating blades arranged on the rotating shaft, the rotating shaft is arranged in the length direction of the rotary kiln body and penetrates through the rotary kiln body, and the two ends of the rotating shaft are fixed outside the rotary kiln body and are in transmission connection with a second driving device; and the rotary kiln body driven by the first driving device and the independent rotating structure driven by the second driving device independently rotate in opposite directions. According to the rotary kiln, high-temperature furnace charge can be prevented from being bonded on the inner wall of the rotary kiln, and the ring forming phenomenon is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of reduction iron smelting technology, especially to a microwave-induction coupling heating pure hydrogen reduction rotary kiln ironmaking system. BACKGROUND

[0002] Hydrogen metallurgy is a new type of smelting process that uses hydrogen as a reducing agent to replace carbon-based fuels for steel production. It has attracted increasing attention in the industry due to its higher reduction efficiency and lower carbon emissions. It is expected to become an important means to achieve carbon neutrality in the steel industry.

[0003] Currently, the hydrogen metallurgy process routes developed based on different reduction devices mainly include: 1) traditional hydrogen-rich blast furnace smelting process, 2) hydrogen-based reduction shaft furnace smelting process, and 3) hydrogen reduction ironmaking process based on fluidized bed reactors. In terms of technical maturity, carbon reduction economy, and carbon reduction potential, the above three processes still have many problems in practical application. In comparison, the hydrogen-rich blast furnace smelting process involves blowing hydrogen-rich gases such as natural gas and coke oven gas into the tuyere to participate in the ironmaking process, reducing the consumption of carbon-containing raw materials such as coke and coal powder to achieve the purpose of emission reduction. It is relatively easy to achieve large-scale application in the current Chinese steel industry. Since this process is based on the traditional blast furnace, coke is still needed as a skeleton support during the reduction of iron, so there is a limit to the amount of hydrogen blowing. According to estimates, the carbon emission reduction range of hydrogen-rich blast furnace reduction is usually between 10% and 20%, which is difficult to support significant emission reduction in the future. The hydrogen-based shaft furnace process with natural gas as the gas source has been mature and widely used abroad. In recent years, domestic steel enterprises have introduced mature foreign technologies mainly using hydrogen by-product from coking as the gas source. Compared with the blast furnace ironmaking process, it can reduce CO2 emissions by more than 50%, and using full hydrogen shaft furnace smelting can achieve carbon emission reduction of more than 90%. However, this technology requires the use of high-grade iron ore resources as raw materials, and the global shortage of high-quality high-grade iron ore resources is a problem. The use of a high proportion of hydrogen gas also raises higher requirements for hydrogen gas heating furnace equipment manufacturing, heating methods, and hydrogen safety. If the raw material and hydrogen supply problems are not solved, it will seriously affect its large-scale application. The fluidized bed hydrogen reduction ironmaking process is based on a fluidized bed reactor and uses ordinary iron ore powder as raw material to produce sponge iron. It has relatively low requirements for iron ore grade and can provide a long-term effective solution for areas with low iron ore resource endowment. However, this process is not yet mature and has the disadvantages of high metalization rate, easy sticking and loss of flow, difficult control, low energy utilization rate and production rate, high production cost, and lack of market competitiveness, which still requires a lot of research and development investment.

[0004] In the prior art, hydrogen metallurgy technology mainly uses shaft furnace and fluidized bed as reduction reaction equipment for research, and at present, the traditional rotary kiln is a mature industrial kiln in the industry and is widely used in the cement and steel industries, and its principle is that the material enters the rotary kiln from the kiln tail, and the material rolls and moves along the circumferential direction and axial direction with the inclination and rotation of the cylinder, and the fuel is sprayed into the kiln from the kiln head, and the exhaust gas generated by combustion exchanges with the material to complete the process. However, the traditional rotary kiln has the problem of "ringing" caused by high-temperature furnace material sticking during operation. Practical new type content

[0005] In view of the above analysis, the present application aims to provide a microwave-induction coupled heating pure hydrogen reduction rotary kiln ironmaking system to solve the "ringing" technical problem caused by high-temperature furnace material sticking in the traditional rotary kiln.

[0006] The main purpose of the present application is achieved through the following technical solutions:

[0007] The present application provides a microwave-induction coupled heating pure hydrogen reduction rotary kiln ironmaking system, which comprises a rotary kiln reduction device body, a first driving device and a second driving device.

[0008] The rotary kiln reduction device body comprises a rotary kiln body and an independent rotating structure; the first driving device is arranged outside the rotary kiln body and can drive the rotary kiln body to rotate;

[0009] The independent rotating structure comprises a rotating shaft and an independent rotating spiral plate arranged thereon, the rotating shaft is arranged along the length direction of the rotary kiln body and penetrates the rotary kiln body, and the two ends of the rotating shaft are fixed outside the rotary kiln body and are in transmission connection with the second driving device.

[0010] The rotary kiln body driven by the first driving device and the independent rotating structure driven by the second driving device rotate in opposite directions.

[0011] In a possible design, the radial length of the independent rotating spiral plate is equal to the distance between the rotating shaft and the inner wall of the rotary kiln body.

[0012] In a possible design, the axial length of the independent rotating spiral plate is equal to the length of the rotary kiln body.

[0013] In a possible design, the microwave-induction coupled heating pure hydrogen reduction rotary kiln ironmaking system further comprises a reduction gas supply unit.

[0014] The feed end of the rotary kiln body is provided with a reduction gas inlet, and the discharge end is provided with a reduction gas outlet; the reduction gas supply unit is connected with the reduction gas inlet and the reduction gas outlet, and the reduction gas supply unit is used to provide normal temperature reduction gas for the rotary kiln body.

[0015] In a possible design, the rotary kiln body comprises, in sequence from the feeding end to the discharging end, a preheating reduction section, a constant-temperature reduction section and a cooling section;

[0016] The preheating reduction section is provided with a microwave heating device; the constant-temperature reduction section is provided with a medium-frequency induction constant-temperature heating device; and the microwave heating device and the medium-frequency induction constant-temperature heating device are both used for heating the iron-containing material.

[0017] In a possible design, the microwave-induction coupled heating pure-hydrogen reduction rotary kiln ironmaking system further comprises a series-tank charging unit.

[0018] The series-tank charging unit is arranged at the feeding end of the rotary kiln body.

[0019] In a possible design, the series-tank charging unit comprises an upper charging tank and a lower charging tank which are connected in series.

[0020] In a possible design, the upper charging tank is provided with an upper feeding valve and an upper discharging valve, and the lower charging tank is provided with a lower feeding valve and a lower discharging valve.

[0021] The upper charging tank and the lower charging tank are both provided with a gas inlet and a gas outlet; and the upper charging tank and the lower charging tank are both connected with a reducing gas supply unit.

[0022] In a possible design, the microwave-induction coupled heating pure-hydrogen reduction rotary kiln ironmaking system further comprises a series-tank discharging unit.

[0023] The series-tank discharging unit is arranged at the discharging end of the rotary kiln body.

[0024] In a possible design, the series-tank discharging unit comprises an upper discharging tank and a lower discharging tank which are connected in series.

[0025] Compared with the prior art, the utility model can realize at least one of the following beneficial effects:

[0026] (1) The utility model is driven by assembling independent rotating structures in the rotary kiln body and adopting two sets of independent driving devices, so that the rotary kiln body and the independent rotating structures therein produce independent reverse rotation, which can improve the composition of the iron-containing material and the uniformity of the heating of the iron-containing material, and promote the reduction of the iron-containing material.

[0027] (2) The independent rotating spiral plate can play a role of forced scraping, reduce the bonding of the furnace charge and avoid the generation of the ring formation phenomenon.

[0028] The above technical solutions can be combined with each other to realize more optional combination solutions. Other features and advantages of the present application will be described in the following description, and some advantages can be apparent from the description or can be understood by implementing the present application. The purposes and other advantages of the present application can be realized and obtained from the contents particularly pointed out in the description, embodiments and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings are only for the purpose of illustrating specific embodiments and are not considered as limiting the present application, and the same reference signs represent the same components throughout the drawings.

[0030] Figure 1 It is a structural schematic view of a microwave-induction coupling heating pure hydrogen reduction rotary kiln ironmaking system of the present application.

[0031] Figure 2 It is a structural schematic view of a rotary kiln furnace body and a corresponding driving device of the independent rotary spiral structure.

[0032] Reference signs:

[0033] 101 - upper charging tank; 102 - lower charging tank; 201 - rotary kiln reduction device body; 202 - microwave heating device; 203 - medium-frequency induction constant-temperature heating device; 204 - independent rotary spiral plate; 301 - upper discharging tank; 302 - lower discharging tank; 401 - reduction gas inlet; 402 - reduction gas outlet; 5 - gear; 6 - first driving reducer; 7 - second driving reducer; 8 - spiral driving shaft. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings form a part of the present application and are used to explain the principles of the present application together with the embodiments of the present application, but are not used to limit the scope of the present application.

[0035] The present application provides a microwave-induction coupling heating pure hydrogen reduction rotary kiln ironmaking system, as shown in Figure 1 and Figure 2 The system comprises a rotary kiln reduction device body 201, a first driving device and a second driving device; the rotary kiln reduction device body 201 comprises a rotary kiln furnace body and an independent rotary structure; the first driving device is arranged outside the rotary kiln furnace body and can drive the rotary kiln furnace body to rotate; the independent rotary structure comprises a rotary shaft and an independent rotary spiral plate 204 arranged thereon, the rotary shaft is arranged along the length direction of the rotary kiln furnace body and penetrates through the rotary kiln furnace body, both end portions of the rotary shaft are fixed outside the rotary kiln furnace body and are in transmission connection with the second driving device; the rotary kiln furnace body driven by the first driving device and the independent rotary structure driven by the second driving device are reversely and independently rotated.

[0036] Specifically, the rotary kiln body of the utility model is a spiral rotary kiln, the rotary kiln body is used for bearing iron-containing raw materials and reducing the iron-containing raw materials; the first driving device comprises a gear 5 and a first driving reducer 6, the gear 5 is installed on the shell of the rotary kiln body, and the first driving reducer 6 can drive the rotary kiln body to rotate by driving the gear 5 to rotate. The independent rotating structure of the utility model comprises a rotating shaft, the length of the rotating shaft is greater than the length of the rotary kiln body, the rotating shaft penetrates the rotary kiln body along the length direction of the rotary kiln body, and the two ends of the rotating shaft are located outside the rotary kiln body and connected with the second driving device, the second driving device comprises a second driving reducer 7 and a spiral driving shaft 8, the second driving reducer 7 can drive the rotating shaft to rotate through the spiral driving shaft 8, and then the rotating shaft drives the independent rotating spiral plate 204 to rotate. When the microwave-induction coupling heating pure hydrogen reduction rotary kiln iron-making system starts to work, the first driving device and the second driving device are started simultaneously, the rotary kiln body and the independent rotating spiral plate 204 rotate reversely and continuously, and the furnace charge moves from the feeding end to the discharging end of the furnace body under the guidance of the independent rotating spiral plate 204, and the independent rotating spiral plate 204 can scrape the inner wall of the rotary kiln body in real time, so that the high-temperature material can be prevented from being bonded on the inner wall of the furnace to form a ring.

[0037] Compared with the prior art, the utility model is equipped with an independent rotating structure in the rotary kiln body, and two sets of independent driving devices are used to make the rotary kiln body and the independent rotating structure rotate reversely and independently, so that the composition of the iron-containing material and the uniformity of the heating can be improved, and the reduction of the iron-containing material can be promoted.

[0038] The utility model adopts iron-containing ore powder as raw material for smelting, the iron-containing ore powder comprises one or more of vanadium-titanium magnetite, high-manganese ore and laterite nickel ore; and further comprises various iron-containing dust and sludge generated in the process of smelting steel and non-ferrous metal. The utility model solves the demand of the current hydrogen-based shaft furnace process for high-grade iron-containing raw materials (which need to be made into iron-containing pellets), and eliminates the ring-forming problem faced by the current traditional rotary kiln.

[0039] In addition, the hydrogen metallurgy process direct reduction iron product cost can be greatly reduced, and the dependence on high-grade iron ore raw materials and foreign equipment technology is broken, and the application of pure hydrogen metallurgy technology is promoted. Among them, the reduction of hydrogen metallurgy process direct reduction iron product cost mainly reflects the following aspects: first, in the raw material cost aspect, compared with the traditional shaft furnace using pellets as raw material, the utility model directly uses iron ore containing iron as smelting raw material, so that the construction cost and preparation cost of the pellet production line can be saved; second, in the operation aspect, the current rotary kiln needs to be shut down for 1-2 months for maintenance and replacement of refractory lining due to the problem of "ringing", so the production efficiency is low; compared with the prior art, the utility model is independently rotated and reversely rotated with the rotary kiln body, which can forcibly scrape the high-temperature furnace charge on the inner wall of the rotary kiln body in real time, avoid the high-temperature furnace charge from sticking to the wall, and thus avoid the "ringing" phenomenon of the rotary kiln, so that the production efficiency of the microwave-induction coupled heating pure hydrogen reduction rotary kiln ironmaking system of the utility model is higher under the same conditions.

[0040] In order to fully scrape the rotary kiln body inner wall, avoid high-temperature material from sticking to the wall to form a ring, the radial length of the independent rotating spiral plate 204 is equal to the radial distance between the rotary shaft and the rotary kiln body inner wall; in addition, the axial length of the independent rotating spiral plate 204 is equal to the length of the rotary kiln body.

[0041] Specifically, when the independent rotating spiral plate 204 is relatively independent and reversely rotated with the rotary kiln body, there is a certain relative speed between the two, so that the material is subjected to a certain stirring intensity in the circumferential direction of the furnace body. The independent rotating spiral plate 204 can not only stir the material in the circumferential direction of the furnace body to make the material composition more uniform, but also can play a role in forcibly scraping the material in the process of spirally advancing at a set speed under the action of the independent rotating spiral plate 204, so as to avoid the high-temperature material from sticking to the wall, and finally avoid the high-temperature material from forming a ring on the wall. In addition, the length of the independent rotating spiral plate 204 is equal to the length of the rotary kiln body, which can fully stir and scrape the material.

[0042] It should be noted that the independent rotating spiral plate 204 of the present application comprises a special-shaped spiral blade, which is made of a steel plate with excellent high-temperature resistance and hydrogen corrosion resistance. The special-shaped spiral blade is installed on the rotating shaft instead of the inner wall of the rotary kiln furnace body, which can reduce the production cost of the iron smelting system. This is because: if the special-shaped spiral blade is installed on the inner wall of the rotary kiln furnace body, special-shaped low refractory bricks (i.e. the refractory material needs to be specially made and customized according to the shape of the spiral) need to be installed. Compared with the installation of conventional cylindrical refractory bricks in the present application, the production and installation of special-shaped low refractory bricks will inevitably increase the production cost and installation cost of low refractory bricks, and will also increase the installation difficulty of refractory bricks, ultimately increasing the production cost of the rotary kiln furnace body for smelting iron. In addition, the special-shaped spiral blade is installed on the rotating shaft instead of the inner wall of the rotary kiln, which can rotate relative to the rotary kiln furnace body, thereby increasing the stirring degree of the material and improving the uniformity of the material, providing convenient conditions for the subsequent reduction reaction of the material.

[0043] It should be noted that the microwave-induction coupled heating pure hydrogen reduction rotary kiln iron smelting system of the present application further comprises a reducing gas supply unit; a reducing gas inlet 401 is provided at the feed end of the rotary kiln furnace body, and a reducing gas outlet 402 is provided at the discharge end; the reducing gas supply unit is connected to the reducing gas inlet 401 through a reducing gas main pipeline, and the reducing gas supply unit is used to provide normal temperature reducing gas to the rotary kiln furnace body.

[0044] Specifically, in view of the endothermic characteristics of hydrogen metallurgical reduction reaction, the present application uses "normal temperature hydrogen for high temperature iron-containing material reduction", that is, the heating device (including microwave heating device 202 and intermediate frequency induction constant temperature heating device 203) is used to heat the iron-containing ore instead of heating hydrogen, and when the temperature reaches the set temperature, the normal temperature reducing gas is introduced for reduction treatment. This operation can avoid the technical problems faced by the prior art using high temperature hydrogen.

[0045] It should be noted that the reducing gas supply unit of the present application further comprises a reducing gas branch pipeline, which is connected to the reducing gas inlet 401 at the feed end of the rotary kiln furnace body through a dehydration device and a dust removal device. The dehydration device is used to dehydrate the unreacted reducing gas discharged through the reducing gas outlet 402, and the dust removal device is used to remove dust from the unreacted reducing gas discharged from the rotary kiln furnace body. The hydrogen gas after dehydration and dust removal is introduced into the rotary kiln furnace body through the reducing gas branch pipeline and the reducing gas inlet 401.

[0046] The reducing gas outlet 402 at the discharge end of the rotary kiln furnace body is connected to the reducing gas inlet 401 through a reducing gas branch pipeline.

[0047] In order to heat the iron-containing powder ore, the rotary kiln body of the utility model comprises a preheating reduction section, a constant temperature reduction section and a cooling section in turn from the feeding end to the discharging end; the preheating reduction section is provided with a microwave heating device 202; the constant temperature reduction section is provided with a medium frequency induction constant temperature heating device 203; the microwave heating device 202 and the medium frequency induction constant temperature heating device 203 are both used for heating the iron-containing material.

[0048] In the prior art, when smelting by using a traditional blast furnace, hot blast furnaces are used to heat air and then spray into the blast furnace for reduction; when smelting by using a traditional hydrogen-based shaft furnace and a hydrogen-based fluidized bed, hydrogen is heated first, and then the reduction of the iron-containing material is carried out. Compared with the prior art, the utility model simultaneously applies two heat sources of microwave heating and induction heating to the rotary kiln for heating the iron-containing material, and solves the problems of hydrogen heating equipment and many materials and heating technologies faced by the current process.

[0049] It should be noted that the microwave heating device 202 and the medium frequency induction constant temperature heating device 203 of the utility model are both used for heating the iron-containing powder ore, and the purpose of heating is to use normal temperature reduction gas to reduce the high-temperature reduction iron-containing powder ore.

[0050] It should be emphasized that the utility model simultaneously applies two heat sources of microwave heating and induction heating to the rotary kiln for heating the iron-containing material, uses the rapid heating characteristics of microwaves to rapidly heat the iron-containing material to the required reduction temperature, and uses the medium frequency induction constant temperature heating device 203 to realize high-temperature maintenance, so as to finally achieve the purpose of reducing production cost and operation cost. This is because: the advantage of microwave heating is fast heating speed, but the disadvantage is high power consumption when maintaining a high temperature, resulting in high production cost, and the speed of induction heating is slower than that of microwave heating, but the power consumption at the same temperature is lower than that of microwave heating. Through the cooperation of the two heating modes, the purpose of rapidly heating and reducing the furnace charge can be achieved, and the operation cost can be reduced.

[0051] The inclination angle of the rotary kiln body of the utility model is 0°; that is, the rotary kiln body is arranged in a horizontal direction.

[0052] Specifically, the rotary kiln body of the utility model is provided with an independent rotating spiral plate 204, which can realize active rotation and discharging, that is, the furnace charge can be discharged automatically without setting an inclination angle.

[0053] Compared with the prior art, the utility model can avoid the problems caused by the inclination of the rotary kiln body, reduce the installation difficulty of the furnace body, improve the stability of the furnace body, and reduce the energy consumption and safety hazards of the furnace body.

[0054] In order to ensure the pure hydrogen environment in the rotary kiln body, prevent the outside air from entering the kiln in the feeding process and produce the safety hidden danger, the microwave-induction coupling heating pure hydrogen reduction rotary kiln ironmaking system further comprises a series tank loading unit; the series tank loading unit comprises the upper loading tank 101 and the lower loading tank 102 which are connected with each other in series; the series tank loading unit is arranged at the feeding end of the rotary kiln body; the series tank loading unit is connected with the feeding port of the rotary kiln body and can provide the iron-containing ore powder for the rotary kiln body.

[0055] Specifically, the upper loading tank 101 is provided with an upper feeding valve and an upper discharging valve, the lower loading tank 102 is provided with a lower feeding valve and a lower discharging valve, the upper loading tank 101 and the lower loading tank 102 are both provided with an air inlet and an air outlet; the upper loading tank 101 is connected with the reduction gas main pipeline through a first branch pipe, the lower loading tank 102 is connected with the reduction gas main pipeline through a second branch pipe, and control valves are arranged on the first branch pipe and the second branch pipe correspondingly. When feeding the rotary kiln body, first, the upper feeding valve is opened, the iron ore powder is loaded into the upper loading tank 101, then the upper feeding valve is closed, the control valves on the first branch pipe and the second branch pipe are opened and hydrogen is filled into the upper loading tank 101 and the lower loading tank 102, the pressure in the upper loading tank 101 and the lower loading tank 102 is kept consistent, then the control valves on the first branch pipe and the second branch pipe are closed to stop filling hydrogen; the upper discharging valve and the lower feeding valve are opened, when the furnace charge in the upper loading tank 101 is completely discharged into the lower loading tank 102, the upper discharging valve and the lower feeding valve are closed; the lower discharging valve is opened, the furnace charge is sent into the rotary kiln body, the above process is repeated to complete the alternate feeding.

[0056] Compared with the prior art, by arranging the series connection of the upper loading tank 101 and the lower loading tank 102 and the corresponding control valves, the air entering the furnace during the feeding process of the rotary kiln body can be prevented, and the pure hydrogen environment in the furnace can be ensured.

[0057] Similarly, in order to ensure the pure hydrogen environment in the rotary kiln, prevent the outside air from entering the kiln in the discharging process and produce the safety hidden danger, the microwave-induction coupling heating pure hydrogen reduction rotary kiln ironmaking system further comprises a series tank discharging unit; the series tank discharging unit comprises an upper discharging tank 301 and a lower discharging tank 302 which are connected with each other in series; the series tank discharging unit is arranged at the discharging end of the rotary kiln body; the series tank discharging unit is connected with the discharging port of the rotary kiln body and can discharge the materials smelted by the rotary kiln to the outside of the furnace.

[0058] Specifically, the upper discharging tank 301 is provided with an upper feeding valve and an upper discharging valve, the lower discharging tank 302 is provided with a lower feeding valve and a lower discharging valve, the upper discharging tank 301 and the lower discharging tank 302 are both provided with an air inlet and an air outlet; the upper discharging tank 301 is connected with the reduction gas main pipeline through a third branch pipe, the lower discharging tank 302 is connected with the reduction gas main pipeline through a fourth branch pipe, and control valves are arranged on the third branch pipe and the fourth branch pipe correspondingly.

[0059] When discharging the rotary kiln body, the air inlet and air outlet of the upper discharge tank 301 and the lower discharge tank 302 are opened first, then the control valves on the third branch pipe and the fourth branch pipe are opened, the air in the upper discharge tank 301 and the lower discharge tank 302 is replaced by hydrogen, the pressure in the upper discharge tank 301 and the lower discharge tank 302 is kept consistent, then the control valves on the third branch pipe and the fourth branch pipe are closed to stop the hydrogen filling; then the upper feeding valve is opened, the reduced product is fully fed into the upper discharge tank 301, then the upper feeding valve is closed, the upper discharge valve and the lower feeding valve are opened, when the reduced product in the upper discharge tank 301 is completely discharged into the lower discharge tank 302, the upper discharge valve and the lower feeding valve are closed; at this time, the lower discharge valve is opened, the reduced product is discharged from the kiln body, and the above process is repeated to complete the alternate discharge.

[0060] Compared with the prior art, the upper discharge tank 301 and the lower discharge tank 302 in series and the corresponding control valves are arranged, so that the air is prevented from entering the rotary kiln body during the discharging process, and the pure hydrogen environment in the furnace is ensured.

[0061] The implementation process of the above-mentioned microwave-induction coupled heating pure hydrogen reduction rotary kiln iron smelting system includes:

[0062] Step 1, the first driving device and the second driving device are started, and the rotary kiln body and the independent rotating spiral structure start independent reverse rotation;

[0063] In the above-mentioned step 1, the first driving reducer 6 rotates through the gear 5 to drive the rotary kiln body to rotate, and at the same time, the second driving reducer 7 drives the independent rotating spiral plate 204 to rotate through the rotating shaft, so that the rotary kiln body and the independent rotating spiral structure start reverse continuous rotation.

[0064] In the above-mentioned step 1, the rotation speed of the rotary kiln body is 0.3-1.5 r / min, which is used to meet the requirements of the design production capacity of the kiln and the real-time metallization rate of DRI.

[0065] In the above-mentioned step 1, the rotary kiln body is reduced in a pure hydrogen (H2> 99.5%) atmosphere, when the rotary kiln body is started for the first time, inert gas (for example, nitrogen) is introduced to replace the air in the kiln, so as to prevent explosion after hydrogen is introduced, the replacement time is determined according to the O2<1% of the kiln tail gas analysis, then pure hydrogen is introduced to replace the nitrogen, and the flow speed of the hydrogen is 28 m / s-38 m / s.

[0066] Step 2, the reducing gas supply unit and the series tank loading unit are started, and then the rotary kiln body is started to be loaded.

[0067] In the above-mentioned step 2, the total iron content TFe in the iron-containing ore powder is 55%-68%.

[0068] In the above step 2, in order to prevent the outside air from entering the kiln during the feeding process and causing safety hazards, the utility model uses a series tank loading unit to load the rotary kiln body, and the specific loading process includes:

[0069] Step 21, first open the upper feeding valve, load the iron ore powder into the upper loading tank 101, and then close the upper feeding valve;

[0070] Step 22, open the control valve on the first branch pipe and the control valve on the second branch pipe, and fill hydrogen into the upper loading tank 101 and the lower loading tank 102, so that the pressure in the upper loading tank 101 and the lower loading tank 102 is consistent, and then close the control valves on the first branch pipe and the second branch pipe to stop filling hydrogen;

[0071] Step 23, open the upper discharge valve and the lower feeding valve, and when the furnace charge in the upper loading tank 101 is completely discharged into the lower loading tank 102, close the upper discharge valve and the lower feeding valve;

[0072] Step 24, open the lower discharge valve, and send the furnace charge into the rotary kiln body, and repeat the above process to complete the feeding of the furnace body.

[0073] In the above step 24, the amount of feeding is controlled according to the filling rate of the raw materials in the rotary kiln of 6% to 8%.

[0074] Step 3, after loading, use the microwave heating device 202 and the intermediate frequency induction constant temperature heating device 203 to heat and reduce the iron-containing ore in the rotary kiln body;

[0075] In the above step 3, the heating and reduction process specifically includes: during loading, simultaneously open the microwave heating device 202 and the intermediate frequency induction constant temperature heating device 203, use the rapid heating characteristics of microwaves to rapidly heat the iron-containing materials in the preheating and reduction section to reach the required temperature for reduction, so as to quickly realize the rapid reduction of the furnace charge; use the intermediate frequency induction constant temperature heating device 203 to generate an intermediate frequency alternating current to heat and reduce the iron-containing furnace charge in the constant temperature reduction section.

[0076] In the above step 3, the temperature of the preheating and reduction section of the microwave heating is 850℃ to 1000℃, and the temperature of the constant temperature reduction section of the intermediate frequency induction heating is 1050℃ to 1100℃.

[0077] In the above step 3, the heating and reduction process of the iron-containing materials specifically includes:

[0078] When the iron-containing fine ore is put into the kiln, the microwave heating device 202 and the intermediate frequency induction constant temperature heating device 203 are started simultaneously, along with the continuous addition of the furnace charge, under the action of the independent rotating spiral plate 204, the furnace charge moves at a constant speed along the axial direction of the rotary kiln body from the feeding end of the rotary kiln body, the furnace charge is rapidly heated to a predetermined reduction temperature after passing through the preheating reduction section, and the pre-reduction of the iron oxide is carried out under the action of hydrogen, and then enters the constant temperature reduction section, and the furnace charge is further reduced to metallic iron.

[0079] Step 4, after reduction, the reduction product is discharged by using the string tank discharge unit.

[0080] Step 41, when discharging, first open the air inlet and air outlet of the lower discharge tank 302 and the upper discharge tank 301, then open the control valves on the third branch pipe and the fourth branch pipe, and use hydrogen to replace the air in the lower discharge tank 302 and the upper discharge tank 301, when the pressure in the upper discharge tank 301 and the lower discharge tank 302 is consistent, close the control valves on the third branch pipe and the fourth branch pipe to stop filling hydrogen;

[0081] Step 42, open the upper feeding valve, and after the reduction product enters the upper discharge tank 301, close the upper feeding valve;

[0082] Step 43, open the upper discharge valve and the lower feeding valve, when the reduction product in the upper discharge tank 301 is completely discharged into the lower discharge tank 302, close the upper discharge valve and the lower feeding valve; at this time, open the lower discharge valve, and the reduction product is discharged from the rotary kiln body, and the above process is repeated to complete the alternate discharge.

[0083] Compared with the prior art, the iron smelting method has the following effects:

[0084] (1) The smelting raw material of the utility model has wide adaptability, and iron ore powder with an iron grade of 55% to 68% high grade is suitable, which solves the problem of the demand for high-grade raw materials in the current hydrogen shaft furnace process.

[0085] (2) The utility model adopts the intermediate frequency induction constant temperature heating device 203 as the heat source of the constant temperature reduction section, which can overcome the shortcomings of high temperature constant temperature power consumption of microwave, and reduce the energy consumption per ton of iron.

[0086] (3) The traditional rotary kiln is adhered to the kiln wall due to the micro-melting of the furnace charge in the constant temperature reduction section, resulting in the phenomenon of "ringing", and the independent rotating spiral plate 204 of the utility model can play the role of forced scraping, reduce the adhesion of the furnace charge, and avoid the generation of the phenomenon of "ringing".

[0087] (4) The utility model discloses utilize the low temperature hydrogen gas in the rotary kiln body that does not participate in the reduction reaction as cooling protection gas to the reduction product carries out heat recovery, and the cooling protection gas after heat recovery is discharged from the kiln body through reduction gas outlet 402, and after the dehydration treatment through the dehydration device and the dust removal through the dust removal device, is introduced into the rotary kiln body through reduction gas branch pipe and reduction gas inlet 401, and the low temperature hydrogen gas after the reduction product heating can promote the reduction of the iron-containing furnace charge, and further improve the metallization rate of the product.

[0088] (5) The existing technology in the hydrogen-rich metallurgical reduction pellet generally adopts nitrogen for cooling, and the nitrogen after cooling is directly discharged, and the waste heat utilization efficiency is low. Compared with the prior art, the utility model adopts hydrogen as the reduction product cooling protection gas, and the space atmosphere in the rotary kiln body will not be destroyed due to the charging and discharging process. In addition, the hydrogen temperature after cooling and heat exchange can reach 50-100 DEG C, and the product waste heat is recovered, so the waste heat utilization efficiency is high.

[0089] (6) The traditional hydrogen metallurgical process adopts the idea of "heating hydrogen gas without heating material", and when the hydrogen-rich reduction gas reacts with the material, the heat exchange between hydrogen gas and the material is slow, and the hydrogen gas needs to be heated in circulation. Therefore, the reaction time is relatively long. In addition, the raw material used in the traditional hydrogen metallurgical process is pellet, and compared with the iron-containing fine ore of the utility model, the pellet is first subjected to heat exchange and then reacts with hydrogen gas, so the reduction time is relatively long. Compared with the prior art, the utility model adopts the idea of "heating material without heating hydrogen gas", and the material used in the utility model is iron-containing fine ore. The iron-containing fine ore is more likely to contact with hydrogen gas, and the reduction efficiency of the hydrogen gas at normal temperature and the heated iron-containing fine ore is relatively high. Therefore, the reaction time is relatively short, and the production efficiency is high.

[0090] Example 1

[0091] The iron-containing fine ore with an iron grade of 56% used in the embodiment is used as raw material, and the raw material loading amount is calculated according to the raw material filling rate of 6% in the rotary kiln body.

[0092] When loading, first, open the upper feeding valve, load the iron ore powder into the upper loading tank 101, and then close the upper feeding valve. Open the control valves on the first branch pipe and the second branch pipe, and fill hydrogen gas into the upper loading tank 101 and the lower loading tank 102, so that the pressure in the upper loading tank 101 and the lower loading tank 102 remains consistent. Then, close the control valves on the first branch pipe and the second branch pipe to stop filling hydrogen gas. Then, open the upper discharge valve and the lower feeding valve. When the furnace charge in the upper loading tank 101 is completely discharged into the lower loading tank 102, close the upper discharge valve and the lower feeding valve. Finally, open the lower discharge valve, and send the furnace charge into the rotary kiln body. Repeat the above process to complete the furnace charging.

[0093] At the same time of loading, 700 m 3Pure hydrogen is continuously injected into the kiln as a reducing agent from the reducing gas inlet 401, and the temperature of the iron-containing burden is raised to 850°C after being heated by the microwave heating device 202. The rotation speed of the rotary kiln body and the independent rotating spiral plate 204 is set to 1.5 r / min, and the residence time of the burden in the preheating and reducing section (microwave heating section) is maintained at 10 min. Subsequently, the burden gradually moves from the microwave heating section to the intermediate frequency induction constant temperature heating section at a constant speed along the axial direction of the kiln under the guidance of the independent rotating spiral plate 204. The burden is heated from 850°C to 1020°C by the intermediate frequency induction constant temperature heating device 203 and is reduced for 40 min at a constant temperature. In the current stage, the iron-containing burden is further reduced to metallic iron. After reduction is completed, the burden moves to the rear half of the rotary kiln at a constant speed under the guidance of the independent rotating spiral plate 204 and is gradually cooled, and then is discharged from the kiln tail into the serial tank discharge unit for discharge.

[0094] When discharging, the burden is first discharged into the upper discharge tank 301 in which air replacement with hydrogen has been completed. After the upper discharge tank is filled, the upper feed valve on the upper discharge tank 301 is closed and the upper discharge valve is opened, so that the burden is discharged into the lower discharge tank 302 and exchanges heat with the normal temperature hydrogen gas introduced into the lower discharge tank 302, so that the direct reduced iron powder at 700°C is reduced to 50°C and then discharged. The metallization rate of the reduced direct reduced iron powder is greater than or equal to 92%.

[0095] The reduced hydrogen gas is discharged from the reducing gas outlet 402, treated by a dehydration device and a dust removal device, and then injected into the kiln for recycling. In addition, the temperature of the hydrogen gas after heat exchange in the lower discharge tank 302 is 200°C-220°C, which is directly injected into the rotary kiln body through a pipeline, thereby improving the utilization efficiency and reduction efficiency of hydrogen gas and reducing production costs.

[0096] Example 2

[0097] In this embodiment, iron concentrate powder with an iron grade of 62% is used as a raw material, and the raw material loading amount is calculated according to a raw material filling rate of 7% in the rotary kiln body.

[0098] When loading, first, the upper feed valve is opened, the iron ore powder is loaded into the upper loading tank 101, and then the upper feed valve is closed. The control valve on the first branch pipe and the control valve on the second branch pipe are opened, and hydrogen is filled into the upper loading tank 101 and the lower loading tank 102, so that the pressure in the upper loading tank 101 and the lower loading tank 102 remains consistent. Then, the control valves on the first branch pipe and the second branch pipe are closed to stop filling hydrogen. Then, the upper discharge valve and the lower feed valve are opened. When the burden in the upper loading tank 101 is completely discharged into the lower loading tank 102, the upper discharge valve and the lower feed valve are closed. Finally, the lower discharge valve is opened, and the burden is fed into the rotary kiln body. The above process is repeated to complete the loading of the kiln body.

[0099] At the same time of loading, 700 m 3Pure hydrogen is continuously injected into the kiln as a reducing agent from the reducing gas inlet 401, and the temperature of the iron-containing burden is raised to 900°C after being heated by the microwave heating device 202. The rotation speed of the rotary kiln body and the independent rotating spiral plate 204 is set to 1.0 r / min, and the residence time of the burden in the preheating and reducing section (microwave heating section) is maintained at 20 min. Subsequently, the burden gradually moves from the microwave heating section to the intermediate frequency induction constant temperature heating section at a constant speed along the axial direction of the kiln under the guidance of the independent rotating spiral plate 204. The burden is heated from 900°C to 1050°C by the intermediate frequency induction constant temperature heating device 203 and is reduced for 60 min at a constant temperature. In the current stage, the iron-containing burden is further reduced to metallic iron. After reduction is completed, the burden moves to the rear half of the rotary kiln at a constant speed under the guidance of the independent rotating spiral plate 204 and is gradually cooled, and then is discharged from the kiln tail into the serial tank discharge unit for discharge.

[0100] When discharging, the burden is first discharged into the upper discharge tank 301 in which air replacement with hydrogen has been completed. After the upper discharge tank is filled, the upper feed valve on the upper discharge tank 301 is closed and the upper discharge valve is opened, so that the burden is discharged into the lower discharge tank 302 and exchanges heat with the normal temperature hydrogen gas introduced into the lower discharge tank 302, so that the direct reduced iron powder at 730°C is reduced to 50°C and then discharged. The metallization rate of the reduced direct reduced iron powder is greater than or equal to 94%.

[0101] The reduced hydrogen gas is discharged from the reducing gas outlet 402, treated by a dehydration device and a dust removal device, and then injected into the kiln for recycling. In addition, the temperature of the hydrogen gas after heat exchange in the lower discharge tank 302 is 200°C-220°C, which is directly injected into the rotary kiln body through a pipeline, thereby improving the utilization efficiency and reduction efficiency of hydrogen gas and reducing production costs.

[0102] Example 3

[0103] In this embodiment, iron concentrate powder with an iron grade of 68% is used as a raw material, and the raw material loading amount is calculated according to the raw material filling rate of 8% in the rotary kiln body.

[0104] When loading, first, the upper feed valve is opened, the iron ore powder is loaded into the upper loading tank 101, and then the upper feed valve is closed. The control valve on the first branch pipe and the control valve on the second branch pipe are opened, and hydrogen is filled into the upper loading tank 101 and the lower loading tank 102, so that the pressure in the upper loading tank 101 and the lower loading tank 102 remains consistent, and then the control valves on the first branch pipe and the second branch pipe are closed to stop filling hydrogen. Then, the upper discharge valve and the lower feed valve are opened. When the burden in the upper loading tank 101 is completely discharged into the lower loading tank 102, the upper discharge valve and the lower feed valve are closed. Finally, the lower discharge valve is opened, and the burden is fed into the rotary kiln body. The above process is repeated to complete the loading of the kiln body.

[0105] At the same time of loading, 700 m 3Pure hydrogen from the reducing gas inlet 401 is continuously injected into the kiln as a reducing agent, and the temperature of the iron-containing furnace charge is raised to 950 DEG C after being heated by the microwave heating device 202. The rotation speed of the rotary kiln body and the independent rotating spiral plate 204 is set to 0.7 r / min, the residence time of the furnace charge in the preheating and reducing section (microwave heating section) is maintained at 30 min, then the furnace charge is gradually moved from the microwave heating section to the intermediate frequency induction constant temperature heating section at a constant speed along the axial direction of the kiln under the guidance of the independent rotating spiral plate 204, the furnace charge is heated from 950 DEG C to 1100 DEG C by the intermediate frequency induction constant temperature heating device 203 and is reduced at a constant temperature for 70 min, and the iron-containing furnace charge is further reduced to metallic iron in the current stage. The furnace charge after reduction is moved to the rear half of the rotary kiln at a constant speed under the guidance of the independent rotating spiral plate 204 and is gradually cooled, and then is discharged from the kiln tail into the serial tank discharge unit for discharge.

[0106] When discharging, the upper discharge tank 301 in which air replacement with hydrogen is completed is first discharged, after the upper discharge tank is filled, the upper feeding valve on the upper discharge tank 301 is closed and the upper discharge valve is opened, so that the material is discharged into the lower discharge tank 302 and exchanges heat with the normal temperature hydrogen gas introduced into the lower discharge tank 302, so that the direct reduced iron powder at 760 DEG C is reduced to 50 DEG C and then discharged, and the metallization rate of the reduced direct reduced iron powder is greater than or equal to 96%.

[0107] The hydrogen after reduction is discharged from the reducing gas outlet 402, treated by the dehydration device and the dust removal device, and then sprayed into the kiln for recycling; in addition, the temperature of the hydrogen after heat exchange in the lower discharge tank 302 is 200 DEG C-220 DEG C, which is directly sprayed into the rotary kiln body through the pipeline, thereby improving the utilization efficiency and reduction efficiency of hydrogen and reducing the production cost.

[0108] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system, characterized in that, The rotary kiln reduction device comprises a rotary kiln reduction device body, a first driving device and a second driving device; The rotary kiln reduction device body comprises a rotary kiln furnace body and an independent rotating structure; the first driving device is arranged outside the rotary kiln furnace body and can drive the rotary kiln furnace body to rotate; The independent rotating structure comprises a rotating shaft and an independent rotating spiral plate arranged thereon; the rotating shaft is arranged along the length direction of the rotary kiln furnace body and penetrates through the rotary kiln furnace body; the two end portions of the rotating shaft are fixed outside the rotary kiln furnace body and are in transmission connection with the second driving device; The rotary kiln furnace body driven by the first driving device and the independent rotating structure driven by the second driving device rotate reversely and independently.

2. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 1, wherein, The radial length of the independent rotating spiral plate is equal to the distance between the rotating shaft and the inner wall of the rotary kiln furnace body.

3. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 2, wherein, The axial length of the independent rotating spiral plate is equal to the length of the rotary kiln furnace body.

4. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 1, wherein, The rotary kiln furnace body comprises, in sequence from the feeding end to the discharging end, a preheating reduction section, a constant-temperature reduction section and a cooling section; The preheating reduction section is provided with a microwave heating device; the constant-temperature reduction section is provided with a medium-frequency induction constant-temperature heating device; the microwave heating device and the medium-frequency induction constant-temperature heating device are both used for heating the iron-containing material.

5. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 1, wherein, The microwave-induction coupled pure hydrogen reduction rotary kiln ironmaking system further comprises a reduction gas supply unit; The feeding end of the rotary kiln furnace body is provided with a reduction gas inlet, and the discharging end thereof is provided with a reduction gas outlet; The reduction gas supply unit is connected with the reduction gas inlet and the reduction gas outlet, and is used for providing normal-temperature reduction gas to the rotary kiln furnace body.

6. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 5, wherein, Further comprising a series tank loading unit; The series tank loading unit is arranged at the feeding end of the rotary kiln furnace body.

7. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 6, wherein, The series tank loading unit comprises an upper loading tank and a lower loading tank which are connected in series.

8. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 7, wherein, The upper loading tank is provided with an upper feeding valve and an upper discharging valve, and the lower loading tank is provided with a lower feeding valve and a lower discharging valve; The upper loading tank and the lower loading tank are both provided with a gas inlet and a gas outlet; the upper loading tank and the lower loading tank are both connected with the reduction gas supply unit.

9. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to any one of claims 1 to 8, characterized in that, Further comprising a series tank discharging unit; The series tank discharging unit is arranged at the discharging end of the rotary kiln furnace body.

10. The microwave-inductively coupled heating pure hydrogen reduction rotary kiln ironmaking system according to claim 9, wherein, The series tank discharging unit comprises an upper discharging tank and a lower discharging tank which are connected in series.

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