Steel mill steam recovery device and application thereof in aerated concrete production

Abstract

The invention discloses a steel mill steam recovery device and application thereof in aerated concrete production, and relates to the technical field of energy recycling, the steel mill steam recovery device comprises a heat exchange part and further comprises a recovery part; the heat exchange part comprises a heat exchange cylinder, a heat preservation inner cylinder is fixedly mounted in the heat exchange cylinder, and a first heat exchange assembly, a second heat exchange assembly and a third heat exchange assembly are fixedly mounted in the heat preservation inner cylinder; the first heat exchange assembly, the second heat exchange assembly and the third heat exchange assembly each comprise a heat exchange box and a heat conduction cone fixedly installed in the heat exchange box. The steel mill steam recovery device has the advantages that during steam recovery, steam is recovered through natural floating of the steam, the steam guide pipe is blocked in the recovery process, steam heat loss caused by entering of external air is avoided, the steel mill steam recovery device is applied to aerated concrete production, the production energy consumption of aerated concrete is greatly reduced, and the production cost is reduced. The method has great economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of energy recovery and utilization, and in particular to a steel plant steam recovery device and application thereof in aerated concrete production. Background Art

[0002] In the rolling mill of a steel plant, steel needs to be heated in a heating furnace for subsequent rolling operations. The heated steel needs to be placed in a water pool for rapid cooling and quenching. After the steel enters the water pool, the water in the water pool will instantly vaporize to form steam under the action of high temperature. In order to improve the utilization of steam, the steam needs to be recovered.

[0003] The existing steam recovery adopts smoke hood recovery, and the steam is sucked into the smoke hood by the fan in the smoke hood and then utilized. Therefore, the publication number CN216925183U discloses a smoke collecting hood for smoke recovery, which includes a smoke hood, and two shielding covers are movably installed on the bottom side of the smoke hood, and the extrusion covers are rotatably installed on the two shielding covers, and sliding brackets are fixedly installed on the two shielding covers, and four sliding brackets are movably installed on the smoke hood. A motor is fixedly installed on one side of the smoke hood, and a driving seat is fixedly installed on the two shielding covers. Threaded holes are opened on the two driving seats, and a first screw rod and a second screw rod are respectively threadedly installed in the two threaded holes, and the threads on the first screw rod and the second screw rod are opposite.

[0004] The above-mentioned smoke hood is provided with two shielding covers, so that when the smoke hood is stopped, the first screw rod and the second screw rod rotate in opposite directions to drive the two driving seats to approach each other, so that the outlet of the smoke hood is closed by the two shielding covers to prevent dust from being scattered, and the two shielding covers can also collect the fallen dust to avoid pollution;

[0005] By setting the pushing frame and the knocking block, when the two shielding covers are closed, the pushing frame can drive the knocking block to intermittently knock the inner wall of the smoke hood, so that the smoke and dust on the inner wall of the smoke hood can be shaken off and recovered by the shielding covers, further avoiding pollution.

[0006] When the above-mentioned smoke hood and the existing smoke hood are in use, air other than steam around the bottom of the smoke hood will be sucked into the smoke hood during suction. Since the temperature of the air is lower than that of the steam, the heat of the steam will be lost. At the same time, the recovered steam needs to be filtered, and this process will cause some heat loss, thereby causing the steam to condense prematurely and reducing the heat utilization rate.

[0007] Therefore, a new type of steel plant steam recovery device and its application in aerated concrete can be used to solve the shortcomings of the prior art. Summary of the invention

[0008] The purpose of the present invention is to solve the problem in the prior art that more heat loss leads to lower energy utilization rate, and to propose a steel plant steam recovery device and its application in aerated concrete production.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A steam recovery device for a steel plant, comprising a heat exchange part and a recovery part;

[0011] The heat exchange part comprises a heat exchange cylinder, a heat preservation inner cylinder is fixedly installed inside the heat exchange cylinder, and a first heat exchange component, a second heat exchange component and a third heat exchange component are fixedly installed inside the heat preservation inner cylinder;

[0012] The first heat exchange assembly, the second heat exchange assembly and the third heat exchange assembly all include a heat exchange box and a heat-conducting cone fixedly installed inside the heat exchange box, and each of the heat exchange boxes is fixedly connected to a flow guide bucket outside, a booster assembly is installed between the heat exchange box and the heat exchange cylinder in the first heat exchange assembly, and a plurality of heat transfer assemblies matching the corresponding heat exchange boxes are installed on the heat exchange cylinder;

[0013] The recovery part comprises a smoke hood, a steam guide pipe is fixedly connected to the smoke hood, the steam guide pipe is fixedly connected to the heat exchange cylinder, and a steam separation component is installed on the steam guide pipe.

[0014] Preferably, a swirl blade is fixedly installed in each of the heat exchange boxes, and the heat conduction cones in each of the heat exchange boxes are arranged in a staggered manner.

[0015] Preferably, the boosting assembly includes a piston plate slidably mounted inside the heat exchange box, a plurality of through holes are provided on the piston plate and the heat exchange box, a one-way tube is fixedly mounted in each of the through holes, a driving mechanism cooperating with the piston plate is installed on the heat exchange cylinder, and a sealing mechanism cooperating with the heat exchange box is installed on the heat exchange cylinder.

[0016] Preferably, the driving mechanism includes a frame fixedly mounted on the outside of the heat exchange cylinder, a second motor fixedly mounted on the frame, a rotating disk fixedly mounted on the driving end of the second motor, an eccentric wheel fixedly mounted on the rotating disk, a connecting rod rotatably mounted on the eccentric wheel, a sleeve fixedly mounted on the frame, a slide plate slidably mounted in the sleeve, the slide plate and the connecting rod are rotatably connected, a push rod fixedly mounted on the end of the slide plate away from the connecting rod, and the push rod passes through the heat exchange cylinder and is fixedly connected to the piston plate.

[0017] Preferably, the blocking mechanism comprises a partition fixedly mounted on the heat exchange cylinder, the heat exchange cylinder is divided into two sections by the partition, an intermittent gear ring and a gear disc meshing with the intermittent gear ring are rotatably mounted on the partition, a first motor is fixedly mounted on the partition, a driving end of the first motor is fixedly connected to the gear disc, and a circular hole matching the heat exchange box is opened on the partition;

[0018] A plurality of incomplete toothed discs are rotatably mounted on the partition, each of which is meshed with an intermittent toothed ring, and a sealing disc matching a circular hole is fixedly mounted on each of the incomplete toothed discs, and each of the sealing discs is in contact with the heat exchange box.

[0019] Preferably, the heat transfer component includes a spiral conduit fixedly wound around the outside of the heat exchange box, both ends of the spiral conduit are fixedly connected to a docking conduit, a pump box is fixedly installed outside the heat exchange cylinder, and the two docking conduits extend out of the heat exchange cylinder and are connected to the pump box.

[0020] Preferably, liquid mercury is stored in the pump box that cooperates with the heat exchange box in the first heat exchange assembly, which is mainly used for heat transfer preheating; high-concentration ethanol is stored in the pump box that cooperates with the heat exchange box in the second heat exchange assembly, which is used for vaporization and pressurization; high-concentration ether is stored in the pump box that cooperates with the heat exchange box in the third heat exchange assembly, which is used for vaporization and pressurization.

[0021] Preferably, the steam separation assembly includes a steam separation box fixedly mounted inside the steam duct, a rotating shaft rotatably mounted on the steam separation box, an upper sealing plate affixed to the upper end of the steam separation box fixedly mounted on the upper portion of the rotating shaft, and a lower sealing plate affixed to the lower end of the steam separation box fixedly mounted on the lower portion of the rotating shaft, and a transmission mechanism matching the rotating shaft is mounted on the steam duct.

[0022] Preferably, the transmission mechanism comprises a motor fixedly mounted on the outside of the steam duct, the driving end of the motor extends into the interior of the steam duct, and the driving end of the motor is connected to the rotating shaft via a bevel gear set.

[0023] The present invention also provides the use of the steam recovery device in the production of aerated concrete, comprising the following steps:

[0024] S1. Prepare aerated concrete slurry: mix iron tailings, cement, lime and desulfurized gypsum in a mass ratio of 60:12:23:5 to obtain a mixture, add 60% of water by mass to the mixture, add a foam stabilizer in an amount of 8% by mass of the water, mix well, add 0.06% of aluminum powder paste by mass of the mixture, mix well, and obtain aerated concrete slurry;

[0025] S2, stirring and foaming;

[0026] S3, pouring test mold;

[0027] S4. Static curing: Place the cast concrete in a static curing room for static curing at a temperature of 55°C.

[0028] S5, demoulding the mold to form a blank;

[0029] S6. Autoclave curing: placing the aerated concrete block in an autoclave curing room for curing;

[0030] S7, drying in an oven to obtain a finished aerated concrete product;

[0031] The static curing room and the autoclave curing room are both connected to the heat exchange component of the steam recovery device through pipelines, and the heat recovered by the steam recovery device is transmitted to the static curing room and the autoclave curing room.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. When the steam recovery device recovers steam, the first heat exchange component is set to recover the heat in the steam for the first time, and then the second heat exchange component and the third heat exchange component are used to recover the remaining heat in the steam. During the first recovery, the steam is dusted, so that the heat is released faster. The multi-stage recovery makes the heat recovery more complete, reduces the loss of heat recovery, and improves the energy utilization rate.

[0034] 2. When the steam recovery device is recovering steam, a motor and a bevel gear set are set to drive the upper sealing plate and the lower sealing plate to intermittently seal the top and bottom of the steam separation box. This can effectively prevent external air from entering the heat exchange cylinder to cause heat loss when the first heat exchange component is operating, thereby greatly improving the retention of heat in the steam.

[0035] 3. When the steam recovery device is recovering steam, a sealing mechanism is provided to seal the steam outlet of the heat exchange box in the first heat exchange assembly. In combination with the use of a piston plate, the steam pressure in the heat exchange box can be increased, thereby increasing the temperature of the steam and accelerating the heat release rate of the steam, thereby achieving the purpose of improving the heat recovery efficiency.

[0036] 4. Applying steam recovery device in aerated concrete production greatly reduces the production energy consumption of aerated concrete.

[0037] In summary, the present invention utilizes the natural flotation of steam to recover steam during steam recovery, and seals the steam pipe during the recovery process to prevent external air from entering and causing steam heat loss. After recovery, the steam is subjected to multi-stage heat exchange treatment to improve the utilization rate of steam heat. In addition, dust mixed in the steam can be removed during heat recovery, which is beneficial to the release of steam heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0039] Figure 1 This is a structural schematic diagram of a steam recovery device for a steel plant proposed by the present invention;

[0040] Figure 2 for Figure 1 Detailed schematic diagram of the structure after being rotated to a certain angle;

[0041] Figure 3 for Figure 1 A schematic detailed view of the plan structure along one of the angles;

[0042] Figure 4 for Figure 3 Detailed schematic diagram of the three-dimensional structure along the AA section;

[0043] Figure 5 for Figure 4 A schematic diagram of the enlarged structure of the first heat exchange component and the driving mechanism;

[0044] Figure 6 for Figure 5 Detailed schematic diagram of the structure after being rotated to a certain angle;

[0045] Figure 7 for Figure 6 Detailed schematic diagram of the internal structure of the middle plugging mechanism;

[0046] Figure 8 for Figure 6 A schematic diagram of the enlarged structure of the middle drive mechanism;

[0047] Fig. 9 for Figure 6 A schematic detailed diagram of the planar structure of the first heat exchange component along one of the angles;

[0048] Fig.10 for Fig. 9 Detailed schematic diagram of the three-dimensional structure along the BB section;

[0049] Fig.11 for Fig.10 Detailed schematic diagram of the structure after being rotated to a certain angle;

[0050] Fig.12 for Figure 1 An enlarged structural schematic detail diagram of the final smoke hood;

[0051] Fig.13 for Fig.12 A schematic detailed view of the plan structure along one of the angles;

[0052] Fig.14 for Fig.13Detailed schematic diagram of the three-dimensional structure along the CC section;

[0053] Fig.15 for Fig.14 The enlarged structural schematic details of the middle motor and steam distribution box;

[0054] Fig.16 for Fig.15 Detailed schematic diagram of the exploded structure;

[0055] Fig.17 is the XRD pattern of aerated concrete product G2;

[0056] Fig.18 is the SEM image of aerated concrete product G2;

[0057] (a) 30,000-fold magnification of the hydration product;

[0058] (b) Hydration product at point B in (a) magnified 50,000 times;

[0059] In the figure: 1 heat exchange cylinder, 2 hanging rope, 3 first motor, 4 smoke hood, 5 second motor, 6 pump box, 7 plugging mechanism, 8 docking duct, 9 insulation inner cylinder, 10 first heat exchange component, 11 second heat exchange component, 12 heat exchange box, 13 spiral duct, 14 guide bucket, 15 push rod, 16 rotating disk, 17 eccentric wheel, 18 sleeve, 19 connecting rod, 20 gear plate, 21 intermittent gear ring, 22 incomplete gear plate, 23 plugging disk, 24 heat transfer cone, 25 swirl blade, 26 piston plate, 27 one-way pipe, 28 steam guide pipe, 29 motor, 30 steam distribution box, 31 upper plugging plate, 32 bevel gear set, 33 rotating shaft, 34 lower plugging plate. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Example 1: Reference Figure 1-Figure 11 , a steam recovery device for a steel plant, comprising a heat exchange portion, and also comprising a recovery portion;

[0062] The heat exchange part comprises a heat exchange cylinder 1, a heat preservation inner cylinder 9 is fixedly installed inside the heat exchange cylinder 1, and a first heat exchange component 10, a second heat exchange component 11 and a third heat exchange component are fixedly installed inside the heat preservation inner cylinder 9;

[0063] The function of the heat preservation tube 9 is to insulate the heat exchange tube 1 to prevent the heat of the steam in the heat exchange tube 1 from being directly transferred to the heat exchange tube 1 and then absorbed by the external environment, thereby effectively preserving the heat in the steam and reducing heat loss.

[0064] The first heat exchange assembly 10, the second heat exchange assembly 11 and the third heat exchange assembly all include a heat exchange box 12 and a heat conductive cone 24 fixedly installed inside the heat exchange box 12. The outside of each heat exchange box 12 is fixedly connected to a flow guide hopper 14. A booster assembly is installed between the heat exchange box 12 and the heat exchange cylinder 1 in the first heat exchange assembly 10.

[0065] The function of the guide bucket 14 is to guide the steam in the heat exchange tube 1 to ensure that the steam in the heat exchange tube 1 smoothly enters the heat exchange box 12, avoid turbulence in the heat exchange tube 1, cause heat loss, and further reduce the loss of steam heat.

[0066] The steam in the heat exchange cylinder 1 will horizontally pass through the guide bucket 14 into the heat exchange box 12 in the first heat exchange component 10. When the steam contacts the heat exchange box 12, most of the heat will be absorbed by the heat exchange box 12 (the heat exchange box 12 is made of metal material. Considering the cost, the heat exchange box 12 is best made of copper).

[0067] The function of the heat-conducting cone 24 is to increase the contact area between the steam and the heat exchange box 12, thereby accelerating the heat conduction rate. At the same time, increasing the contact area can also effectively improve the heat conduction efficiency. There will be some heat loss in the process of heat conduction. The longer the time, the greater the loss. Therefore, the heat conduction speed is accelerated here to shorten the transfer time, which can reduce the heat loss to a certain extent.

[0068] In addition, the heat-conducting cones 24 are arranged in a staggered manner to form an interception net in the heat exchange box 12. Steam will liquefy on the heat-conducting cones 24, and the liquefaction will cause dust in the steam to adhere to the heat-conducting cones 24, so that the steam can be dust-removed and can be regarded as a filter.

[0069] A swirl blade 25 is fixedly installed in each heat exchange box 12, and the heat conduction cones 24 in each heat exchange box 12 are arranged in a staggered manner. The function of the swirl blade 25 is to make the steam form a swirl after entering the heat exchange box 12. The centrifugal force generated by the swirl can diffuse the steam to the surroundings, increasing the chance of the steam contacting the inner wall of the heat exchange box 12, so that the steam can contact the inner wall of the heat exchange box 12 more thoroughly, the heat exchange efficiency is higher, the heat exchange amount is larger, and the heat loss is lower.

[0070] The booster assembly includes a piston plate 26 slidably mounted inside the heat exchange box 12. A plurality of through holes are provided on the piston plate 26 and the heat exchange box 12. A one-way pipe 27 is fixedly mounted in each through hole. A driving mechanism matching the piston plate 26 is mounted on the heat exchange cylinder 1.

[0071] The booster assembly can increase the steam pressure in the heat exchange box 12, thereby increasing the temperature of the steam and accelerating the heat release rate of the steam, thereby achieving the purpose of improving the heat recovery efficiency.

[0072] When the piston plate 26 moves toward the side close to the heat-conducting cone 24, the space between the heat-conducting cone 24 and the piston plate 26 inside the heat exchange box 12 is compressed (during the compression process, the end of the heat exchange box 12 away from the piston plate 26 needs to be blocked), and the pressure increases to pressurize the steam. Increasing the steam pressure will increase the heat of the steam, thereby improving the heat exchange efficiency;

[0073] The expansion of the space on the other side of the heat exchange box 12 will draw the steam in the heat exchange tube 1 into the heat exchange box 12, which requires the cooperation of a one-way pipe 27, which can prevent the steam from flowing back.

[0074] The driving mechanism includes a frame fixedly mounted on the outside of the heat exchange cylinder 1, a second motor 5 is fixedly mounted on the frame, a rotating disk 16 is fixedly mounted on the driving end of the second motor 5, an eccentric wheel 17 is fixedly mounted on the rotating disk 16, a connecting rod 19 is rotatably mounted on the eccentric wheel 17, a sleeve 18 is fixedly mounted on the frame, a slide plate is slidably mounted in the sleeve 18, the slide plate is rotatably connected to the connecting rod 19, a push rod 15 is fixedly mounted on the end of the slide plate away from the connecting rod 19, and the push rod 15 passes through the heat exchange cylinder 1 and is fixedly connected to the piston plate 26.

[0075] The driving end of the second motor 5 rotates to drive the rotating disk 16 fixedly connected thereto to rotate. The rotation of the rotating disk 16 drives the eccentric wheel 17 fixedly connected thereto to rotate. The eccentric wheel 17 will make a circular motion around the central axis of the rotating disk 16. The rotation of the eccentric wheel 17 will change the horizontal position of the connecting rod 19, so that the connecting rod 19 makes a reciprocating motion in the horizontal direction, so the connecting rod 19 will drive the slide plate to move, thereby changing the position of the slide plate in the sleeve 18. The movement of the slide plate drives the push rod 15 to move, thereby driving the piston plate 26 to move, thereby achieving the purpose of steam suction and exhaust.

[0076] The heat exchange cylinder 1 is provided with a plugging mechanism 7 which matches with the heat exchange box 12;

[0077] The blocking mechanism 7 includes a partition fixedly mounted on the heat exchange tube 1, the heat exchange tube 1 is divided into two sections by the partition, an intermittent gear ring 21 and a toothed disc 20 meshing with the intermittent gear ring 21 are rotatably mounted on the partition, a first motor 3 is fixedly mounted on the partition, a driving end of the first motor 3 is fixedly connected to the toothed disc 20, and a circular hole matching the heat exchange box 12 is opened on the partition;

[0078] A plurality of incomplete toothed discs 22 are rotatably mounted on the partition, each of which is meshed with the intermittent toothed ring 21 , and a sealing disc 23 matching the circular hole is fixedly mounted on each incomplete toothed disc 22 , and each sealing disc 23 is in contact with the heat exchange box 12 .

[0079] When boosting is performed, the first motor 3 and the second motor 5 operate synchronously. The rotation of the driving end of the first motor 3 drives the gear disc 20 fixedly connected thereto to rotate. The rotation of the gear disc 20 drives the intermittent gear ring 21 meshing therewith to rotate. The rotation of the intermittent gear ring 21 drives the multiple incomplete gear discs 22 meshing therewith to rotate, thereby driving the sealing disc 23 fixedly connected to the incomplete gear disc 22 to rotate. The multiple sealing discs 23 form a closed circular disc for sealing the port of the heat exchange box 12.

[0080] Embodiment 2: This embodiment is different from the embodiment 1 in that: Figure 1-Figure 5 The heat exchange cylinder 1 is provided with a plurality of heat transfer components matched with the corresponding heat exchange boxes 12 .

[0081] The heat transfer component includes a spiral conduit 13 fixedly wound around the outside of the heat exchange box 12. Both ends of the spiral conduit 13 are fixedly connected to a docking conduit 8. A pump box 6 is fixedly installed outside the heat exchange cylinder 1. Both docking conduits 8 extend out of the heat exchange cylinder 1 and are connected to the pump box 6.

[0082] The pump box 6 includes a heat storage device and a circulation device. The heat on the heat exchange box 12 will be absorbed by the heat exchange fluid in the spiral conduit 13, and then enter the pump box 6 through the docking conduit 8;

[0083] The operation of the heat storage device in the pump box 6 can be controlled by a control system to absorb and store the heat of the heat exchange fluid in the docking conduit 8. The heat storage device and the circulation device are both common existing devices and will not be elaborated on here.

[0084] Liquid mercury is stored in the pump box 6 matched with the heat exchange box 12 in the first heat exchange assembly 10, which is mainly used for heat transfer preheating. Liquid mercury has a good heat transfer effect and a high thermal conductivity, which can absorb and conduct the heat on the heat exchange box 12 to a greater extent and reduce heat loss. The outside of the docking conduit 8 is wrapped with a heat insulation film, which is used to keep the docking conduit 8 warm and reduce heat loss during heat conduction.

[0085] The pump box 6 matched with the heat exchange box 12 in the second heat exchange assembly 11 stores high-concentration ethanol for vaporization and pressurization; the pump box 6 matched with the heat exchange box 12 in the third heat exchange assembly stores high-concentration ether for vaporization and pressurization;

[0086] The first heat exchange component 10 is provided to recover the heat in the steam for the first time, and then the second heat exchange component 11 and the third heat exchange component are used to recover the remaining heat in the steam. The steam is dusted during the first recovery, so that the heat is released faster. The multi-stage recovery makes the heat recovery more complete, reduces the loss of heat recovery, and improves the energy utilization rate.

[0087] High-purity ethanol and high-purity ether both have good thermal conductivity, and their boiling points are lower than that of water. Therefore, the heat required to form steam is lower. In this way, steam can be formed under the action of low heat, and then the volume is changed by steam expansion. The steam thermal energy is stored through energy storage equipment and used to release the pressure of aerated concrete in aerated concrete.

[0088] Embodiment 3: This embodiment is different from the technical solution of Embodiment 2 in that: Figure 1-Figure 4 - Figure 12-16 The recovery part includes a smoke hood 4, which is fixedly connected with a steam guide pipe 28. The steam guide pipe 28 is fixedly connected with the heat exchange tube 1. A steam separation component is installed on the steam guide pipe 28. The outside of the steam guide pipe 28 is also wrapped with a thermal insulation film to reduce the heat loss of steam.

[0089] The steam separation assembly includes a steam separation box 30 fixedly mounted inside the steam duct 28, a rotating shaft 33 rotatably mounted on the steam separation box 30, an upper sealing plate 31 abutting against the upper end of the steam separation box 30 is fixedly mounted on the upper portion of the rotating shaft 33, and a lower sealing plate 34 abutting against the lower end of the steam separation box 30 is fixedly mounted on the lower portion of the rotating shaft 33, and a transmission mechanism matching the rotating shaft 33 is mounted on the steam duct 28.

[0090] When the steam enters the hood 4 under the action of its own buoyancy, it will then enter the steam separation box 30, and finally enter the heat exchange tube 1 through the steam separation box 30. If the steam enters the heat exchange tube 1 directly through the steam separation box 30, the heat exchange tube 1 will be connected to the outside world, and the negative pressure generated by the first heat exchange component 10 will suck the outside air into the heat exchange tube 1 through the hood 4. The outside air temperature is lower than the steam temperature, which will absorb the heat on the steam, resulting in reduced steam heat loss. Therefore, when the first heat exchange component 10 sucks the steam into the heat exchange box 12, it is necessary to keep the heat exchange tube 1 isolated from the outside world, which is achieved by using a steam separation component here;

[0091] The steam dividing box 30 divides the steam conduit 28 into three steam inlet bins, and the steam inlet area of ​​each steam inlet bin is the same.

[0092] The rotation of the driving end of the motor 29 will drive the rotating shaft 33 to rotate, thereby driving the upper blocking plate 31 and the lower blocking plate 34 to rotate. The upper blocking plate 31 and the lower blocking plate 34 are both designed in two-thirds of the original design, and are staggered. When rotating, the upper part of one of the steam inlet bins can always be kept connected to the heat exchange cylinder 1, while the bottom is not connected to the smoke hood 4, while the tops of the other two steam inlet bins are not connected to the heat exchange cylinder 1, and the bottoms are connected to the smoke hood 4. When sucking steam, only the steam in the steam inlet bin connected to the heat exchange cylinder 1 will be sucked into the heat exchange box 12;

[0093] It effectively prevents external air from entering the heat exchange tube 1 to cause heat loss, greatly increases the heat retention in the steam, and thus improves the utilization rate of thermal energy.

[0094] The transmission mechanism includes a motor 29 fixedly mounted on the outside of the steam duct 28 , a driving end of the motor 29 extends into the interior of the steam duct 28 , and the driving end of the motor 29 is connected to a rotating shaft 33 via a bevel gear set 32 ​​.

[0095] The rotation of the driving end of the motor 29 will drive the rotating shaft 33 to rotate through the bevel gear set 32, which is used for transmission connection. The longitudinal transmission is converted into a transverse transmission, which can avoid the motor 29 being installed in the steam guide pipe 28, which is beneficial to the smooth passage of steam.

[0096] The specific operation steps of this device are as follows:

[0097] First, the steam generated by the steel plant will float up under the action of natural buoyancy and enter the steam inlet bin in the smoke hood 4. At this time, the first motor 3, the second motor 5 and the motor 29 are turned on. The motor 29 drives the upper blocking plate 31 and the lower blocking plate 34 to rotate, so that the steam inlet bin is indirectly connected to the heat exchange cylinder 1.

[0098] The driving end of the second motor 5 rotates to drive the rotating disk 16 fixedly connected thereto to rotate, and the rotating disk 16 rotates to drive the eccentric wheel 17 fixedly connected thereto to rotate. The eccentric wheel 17 will make a circular motion around the central axis of the rotating disk 16. The rotation of the eccentric wheel 17 will change the horizontal position of the connecting rod 19, so that the connecting rod 19 will make a reciprocating motion in the horizontal direction, so the connecting rod 19 will drive the slide plate to move, thereby changing the position of the slide plate in the sleeve 18. The movement of the slide plate drives the push rod 15 to move, thereby driving the piston plate 26 to move;

[0099] When the piston plate 26 moves toward the side close to the heat-conducting cone 24, the space between the heat-conducting cone 24 and the piston plate 26 inside the heat exchange box 12 is compressed, and the space on the other side of the heat exchange box 12 expands, which will draw the steam in the heat exchange cylinder 1 into the heat exchange box 12, which requires the one-way pipe 27 to complete.

[0100] In the heat exchange cylinder 1, the plugging mechanism 7 needs to be kept in operation during steam absorption to plug the ports of the heat exchange box 12. The driving end of the first motor 3 rotates to drive the toothed disc 20 fixedly connected thereto to rotate. The rotation of the toothed disc 20 drives the intermittent toothed ring 21 meshing therewith to rotate. The rotation of the intermittent toothed ring 21 drives the multiple incomplete toothed discs 22 meshing therewith to rotate, thereby driving the plugging disc 23 fixedly connected to the incomplete toothed disc 22 to rotate. The multiple plugging discs 23 form a closed disc to plug the ports of the heat exchange box 12.

[0101] The steam sucked into the first heat exchange component 10 will be pressurized by the booster component, and then contact the heat exchange box 12 in the first heat exchange component 10, and the heat in the steam will be transferred to the heat exchange box 12. The heat on the heat exchange box 12 will be absorbed by the heat exchange liquid in the spiral conduit 13, and then enter the pump box 6 through the docking conduit 8. The control system can be used to control the operation of the heat storage device in the pump box 6, and the heat of the heat exchange liquid in the docking conduit 8 can be absorbed and stored for use in the static curing room. The remaining heat in the steam will be absorbed by the second heat exchange component 11 and the third heat exchange component for use in the steam curing room.

[0102] Embodiment 4: Application of the above steam recovery device in aerated concrete production comprises the following steps:

[0103] S1. Prepare aerated concrete slurry: mix iron tailings, cement, lime and desulfurized gypsum in a mass ratio of 60:12:23:5 to obtain a mixture, add 60% of water by mass to the mixture, add a foam stabilizer in an amount of 8% by mass of the water, mix well, add 0.06% of aluminum powder paste by mass of the mixture, mix well, and obtain aerated concrete slurry;

[0104] S2, stirring and foaming;

[0105] S3, pouring test mold;

[0106] S4. Static curing: Place the cast aerated concrete in a static curing room for static curing at a temperature of 55°C.

[0107] S5, demoulding the mold to form a blank;

[0108] S6. Autoclave curing: placing the aerated concrete block in an autoclave curing room for curing;

[0109] S7, drying in an oven to obtain a finished aerated concrete product;

[0110] The static curing room and the autoclave curing room are both connected to the heat exchange component of the steam recovery device through pipelines, and the heat recovered by the steam recovery device is transmitted to the static curing room and the autoclave curing room.

[0111] Results Analysis

[0112] 1. The influence of iron tailings fineness on product strength

[0113] The grinding time of iron tailings was controlled to be 10min, 20min, 30min, 40min, and 50min, and the dry material mass ratio of raw materials was tentatively set to be 60% iron tailings mass fraction, 12% cement mass fraction, 23% lime mass fraction, and 5% desulfurized gypsum mass fraction. The amount of aluminum powder paste was 0.06% of the dry material mass ratio, the water-to-material ratio was 0.6, the foam stabilizer was 8% of the total water consumption, and the static curing temperature was 55°C. The relationship between the wet grinding time and the product strength of the autoclaved aerated concrete prepared under the above different wet grinding times is shown in Table 1.

[0114] Table 1 Relationship between iron tailings wet grinding time and aerated concrete performance

[0115]

[0116] The different fineness of iron tailings has a certain influence on the pouring stability of slurry and the strength of the product. Under the same water-to-material ratio, if the fineness is too fine, the viscosity of the slurry will increase, the gas generation speed will be inconsistent with the slurry thickening speed, and the phenomenon of holding gas will occur; if the fineness is too coarse, the slurry will be too thin, and it is easy to cause mold collapse, bubbling, and sinking.

[0117] It can be seen from Table 1 that when the tailings wet grinding time is 30 minutes, the product compressive strength is the highest, reaching 4.80MPa. This shows that when the tailings wet grinding time is 30 minutes, the slurry thickening speed and the gas generation speed are coordinated, which is conducive to the formation of a uniform pore structure. Considering factors such as energy consumption and production efficiency, the wet grinding time of iron tailings in the test is determined to be 30 minutes.

[0118] 2. Design of mix ratio of iron ore tailings aerated concrete

[0119] In order to maximize the use of iron tailings, the iron tailings wet-milled for 30 minutes were selected with a dosage between 55% and 65%, the gypsum dosage was 5%, the cement dosage was temporarily set at 5% to 15%, the lime dosage was 15% to 30%, the aluminum powder paste dosage was 0.06% of the dry material mass ratio, the water-to-material ratio was 0.60, the foam stabilizer was 8% of the total water consumption, and the static curing temperature was 55°C. Based on a large number of exploratory experiments in the early stage, the design of the main raw material mix ratio is shown in Table 2.

[0120] Table 2 Performance test results of aerated concrete with different raw material ratios

[0121]

[0122]

[0123] From Table 2, we can see that when the tailings dosage is 60%, the cement dosage is 10%, and the lime dosage is 25%, the performance of the product reaches the best, so Q2 is determined as the optimal ratio.

[0124] 3. Effect of static curing temperature on the performance of aerated concrete

[0125] Under the same raw material ratio, different curing temperatures will result in different speeds of thickening of the cast slurry, and will not be completely consistent with the gas emission rate of the aluminum paste. To obtain the best strength of the product, the gas emission rate of the aluminum paste must be synchronized with the thickening rate of the slurry, which is conducive to the formation of a better pore structure inside the product and is the guarantee for the product to obtain better strength. The test results of the effect of curing temperature on strength are shown in Table 5.

[0126] Table 5 Effect of curing temperature on the performance of aerated concrete products

[0127]

[0128] It can be seen from Table 5 that when the curing temperature is 40-60℃, the strength of aerated concrete products is also increasing. When the curing temperature is 60-70℃, the strength tends to decrease. When the curing temperature is 60℃, the absolute dry compressive strength of aerated concrete products reaches 4.74MPa. This shows that the increase in temperature is beneficial to the strength development of the product, but when the temperature is too high, the water evaporates too quickly during the product molding, and the slurry consistency changes rapidly, resulting in inconsistent slurry thickening speed and aluminum powder initiation speed, and the gas generation is not smooth, resulting in air holding phenomenon, which is not conducive to the later strength development of the product. Therefore, 60℃ is selected as the optimal static curing temperature.

[0129] 4. Effect of gypsum content on the performance of aerated concrete

[0130] In the production of aerated concrete, gypsum is used as a regulator. Its main function is to inhibit the dissolution of lime, slow down the gas generation rate of aluminum paste, and prolong the thickening time of slurry. On the basis of the previously determined Q2 mix ratio, the amount of cement and lime calcium materials is kept unchanged, the amount of foam stabilizer is kept unchanged, the curing temperature is 60℃, the gypsum dosage is adjusted, and the amount of iron tailings is adjusted accordingly. The effect of gypsum dosage on strength is shown in Table 3.

[0131] Table 3 Effect of gypsum content on the performance of aerated concrete

[0132]

[0133] It can be seen from Table 3 that when the gypsum content is 5%, the specific strength (specific strength = compressive strength / density) of aerated concrete products reaches 8.30MPa. When the gypsum content is too high or too low, the strength of the products decreases to varying degrees, especially when the content is 4% or 6%, the strength decreases more.

[0134] 5. Composition and structure of iron ore tailings aerated concrete

[0135] In order to verify the reliability of formula G2, X-ray diffraction analysis was used to conduct a preliminary study on the microstructure of sample G2. The test results are as follows: Fig.17 As shown. Fig.17 It can be seen that after autoclaving, the main phase of the newly formed G2 product is 0.9 nm tobermorite (Ca5Si6O 18 H2), 1.1nm tobermorite (Ca5Si6O 17 5H2O) and 1.4nm tobermorite (Ca5Si6O 18 H2·8H2O), in nature, there is also the coexistence of tobermorite with different bound water contents. The formation of tobermorite with various bound water contents may be related to the unevenness of the composition (including water content) and particle size in the product. The formation of the hydration product tobermorite ensures the good strength of aerated concrete. The biotite and calcite in the iron tailings still exist after high-temperature autoclaving conditions, but the diffraction peak intensity has decreased. It can be determined that these minerals are less active under the autoclaving conditions used in this research system and have not fully participated in the reaction. However, under autoclaving conditions, the intensity of the diffraction peak of hematite has not changed, which shows that hematite does not participate in the reaction in the entire system and acts as an aggregate in the product. The original gangue minerals plagioclase, hornblende, and chlorite phases in the tailings are decomposed after autoclaving and curing, entering the tobermorite structure to form new mineral phases. These new mineral phases are extremely beneficial to the development of product strength. The diffraction peak intensity of quartz has decreased significantly, and some residual quartz exists as the main aggregate in the product. In addition Fig.17 There is a certain diffuse background in the spectrum, which can prove that there are amorphous substances or substances with extremely low crystallinity (no diffraction peak) in the product G2, which leads to the broadening of the diffraction peak and affects the background value of the XRD diffraction spectrum.

[0136] The microstructure of aerated concrete products after high temperature autoclaving is shown in Fig.18 (a), it can be seen that the hydration products are densely clustered in the figure, and low-crystallinity or amorphous CSH gel (see A in the figure) and a large amount of willow-shaped or leaf-shaped tobermorite with relatively good crystallinity (see B in the figure) are generated on the cross section of the sample. The CSH gel acts as a "binder" to bond these dense hydration products together to form a good network framework structure. This structure can change the pore structure of the product, better resist external loads, and is not easy to cause stress concentration under stress, which plays a certain role in improving the strength of the product. Fig.18 (b) Yes Fig.18(a) From the enlarged image at B, it can be seen that the hydration product tobermorite has a good crystal morphology, and there are unreacted quartz particles around the plate-like or flake-like objects. Due to the different selection of the field of view, the number of quartz particles also varies.

[0137] 6. Mechanism analysis of preparing aerated concrete from iron tailings

[0138] The reaction process of aerated concrete in the iron ore tailings-cement-lime system is the same as that of other types of aerated concrete, including a static curing stage and a steam-pressed curing stage under high temperature and high pressure.

[0139] During the static curing stage, cement in the casting slurry and the green body is hydrated, quicklime is dissolved, and low-crystallinity or amorphous CSH gel, Ca(OH)2 and a small amount of hydrated calcium sulfoaluminate, etc. are produced. Under the conditions of hot alkali excitation, a small amount of SiO2 components in iron tailings and silica sand begin to show chemical activity, reacting with Ca(OH)2 produced by quicklime dissolution to form CSH gel, which makes the green body of the product gain early strength and is convenient for handling and cutting.

[0140] During the autoclaving stage, as the temperature rises, more SiO2 in the iron tailings dissolves faster and reacts with Ca(OH)2 to form CSH gel. At the same time, the double-alkali silicate in the cement reacts with SiO2 to form tobermorite and CSH gel. - Due to the action of ions, the Si-O and Al-O bonds in the system are broken, which makes the SiO2 and Al2O3 components in the raw material system active, and combines with Ca(OH)2 to form hydration products, forming a supersaturated solution. By maintaining a sufficient steam curing time, the hydration products are generated, crystallized, nucleated, and interwoven into a network, showing gel properties. Because some minerals in iron tailings and silica sand participate in the generation reaction of hydration products under high temperature autoclave conditions, more CSH gel and tobermorite are formed. These hydration products are tightly wrapped on the surface of the coarser iron tailings particles, giving the product strength. Combined with the above mechanism analysis, it can be seen that the strength of aerated concrete is obtained by cementing other components that do not participate in the reaction together, such as CSH gel and tobermorite, which are formed by the reaction of cement, lime and the active components SiO2 and Al2O3 in the raw material system.

[0141] The present invention applies a steam recovery device to the production of aerated concrete, successfully utilizes iron tailings to prepare A3.5 and B06 grade autoclaved aerated concrete that meets national standards, broadens the range of raw materials used for aerated concrete, solves the problem of resource shortage in some manufacturers that use aeolian sand and fly ash resources to produce aerated concrete, and is of great significance for the comprehensive utilization of a large amount of iron tailings, saving tailings management costs and protecting the mine environment.

[0142] Using the raw material system of cement-lime-iron tailings, through a large number of experimental studies, the process parameters and optimal scheme for preparing autoclaved aerated concrete using iron tailings were determined. The iron tailings were ground for 30 minutes, the mass ratio of dry materials was: iron tailings: lime: cement: gypsum = 60:25:10:5, the amount of aluminum powder paste added was 0.06% of the total dry material, the water-to-material ratio was 0.60, the foam stabilizer was 8% of the total water consumption, the slurry pouring temperature was 50°C, the static curing temperature was 60°C, the steaming pressure was 1.25MPa, the temperature was 180°C, and the autoclaving time was 12h.

[0143] Iron tailings aerated concrete can form tobermorite with different bound water contents during autoclaving. The original mineral component in the tailings - hematite basically does not participate in the hydrothermal reaction, and it acts as an aggregate in the aerated concrete products.

[0144] The application of steel plant steam recovery device in aerated concrete production has greatly reduced the energy consumption of aerated concrete production and has great economic benefits.

[0145] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A steam recovery device for a steel plant, comprising a heat exchange part, characterized in that: It also includes a recycling department; The heat exchange part comprises a heat exchange cylinder (1), a heat insulation inner cylinder (9) is fixedly installed inside the heat exchange cylinder (1), and a first heat exchange component (10), a second heat exchange component (11) and a third heat exchange component are fixedly installed inside the heat insulation inner cylinder (9); The first heat exchange assembly (10), the second heat exchange assembly (11) and the third heat exchange assembly all comprise a heat exchange box (12) and a heat-conducting cone (24) fixedly mounted inside the heat exchange box (12); the outside of each heat exchange box (12) is fixedly connected to a flow guide hopper (14); a booster assembly is installed between the heat exchange box (12) and the heat exchange cylinder (1) in the first heat exchange assembly (10); and a plurality of heat transfer assemblies matching the corresponding heat exchange boxes (12) are installed on the heat exchange cylinder (1); The recovery section comprises a smoke hood (4), a steam guide pipe (28) is fixedly connected to the smoke hood (4), the steam guide pipe (28) is fixedly connected to the heat exchange cylinder (1), and a steam separation component is installed on the steam guide pipe (28).

2. The steel plant steam recovery device according to claim 1, characterized in that: A swirl blade (25) is fixedly installed in each heat exchange box (12), and the heat conduction cones (24) in each heat exchange box (12) are arranged in a staggered manner.

3. The steel plant steam recovery device according to claim 1, characterized in that: The booster assembly comprises a piston plate (26) slidably mounted inside a heat exchange box (12); a plurality of through holes are provided on the piston plate (26) and the heat exchange box (12); a one-way tube (27) is fixedly mounted in each of the through holes; a driving mechanism matched with the piston plate (26) is mounted on the heat exchange cylinder (1); and a sealing mechanism (7) matched with the heat exchange box (12) is mounted on the heat exchange cylinder (1).

4. The steel plant steam recovery device according to claim 3, characterized in that: The driving mechanism comprises a frame fixedly mounted on the outside of the heat exchange cylinder (1), a second motor (5) fixedly mounted on the frame, a rotating disk (16) fixedly mounted on the driving end of the second motor (5), an eccentric wheel (17) fixedly mounted on the rotating disk (16), a connecting rod (19) rotatably mounted on the eccentric wheel (17), a sleeve (18) fixedly mounted on the frame, a slide plate slidably mounted in the sleeve (18), the slide plate and the connecting rod (19) are rotatably connected, a push rod (15) fixedly mounted on one end of the slide plate away from the connecting rod (19), the push rod (15) passes through the heat exchange cylinder (1) and is fixedly connected to the piston plate (26).

5. The steel plant steam recovery device according to claim 3, characterized in that: The blocking mechanism (7) comprises a partition fixedly mounted on the heat exchange tube (1), the heat exchange tube (1) being divided into two sections by the partition, an intermittent gear ring (21) and a toothed disc (20) meshing with the intermittent gear ring (21) being rotatably mounted on the partition, a first motor (3) being fixedly mounted on the partition, a driving end of the first motor (3) being fixedly connected to the toothed disc (20), and a circular hole matching the heat exchange box (12) being provided on the partition; A plurality of incomplete toothed discs (22) are rotatably mounted on the partition, each of the incomplete toothed discs (22) is meshed with the intermittent toothed ring (21), and a sealing disc (23) matching the circular hole is fixedly mounted on each of the incomplete toothed discs (22), and each of the sealing discs (23) is in contact with the heat exchange box (12).

6. The steel plant steam recovery device according to claim 1, characterized in that: The heat transfer component comprises a spiral conduit (13) fixedly wound around the outside of a heat exchange box (12), both ends of the spiral conduit (13) being fixedly connected to a docking conduit (8), a pump box (6) being fixedly mounted on the outside of the heat exchange cylinder (1), and both docking conduits (8) extending out of the heat exchange cylinder (1) and connected to the pump box (6).

7. The steel plant steam recovery device according to claim 1, characterized in that: Liquid mercury is stored in the pump box (6) matched with the heat exchange box (12) in the first heat exchange component (10), and is mainly used for heat transfer preheating; high-concentration ethanol is stored in the pump box (6) matched with the heat exchange box (12) in the second heat exchange component (11), and is used for vaporization and pressurization; high-concentration ether is stored in the pump box (6) matched with the heat exchange box (12) in the third heat exchange component, and is used for vaporization and pressurization.

8. The steel plant steam recovery device according to claim 1, characterized in that: The steam separation assembly comprises a steam separation box (30) fixedly mounted inside the steam guide pipe (28); a rotating shaft (33) is rotatably mounted on the steam separation box (30); an upper sealing plate (31) abutting against the upper end of the steam separation box (30) is fixedly mounted on the upper portion of the rotating shaft (33); and a lower sealing plate (34) abutting against the lower end of the steam separation box (30) is fixedly mounted on the lower portion of the rotating shaft (33); and a transmission mechanism matched with the rotating shaft (33) is mounted on the steam guide pipe (28).

9. The steel plant steam recovery device according to claim 8, characterized in that: The transmission mechanism comprises a motor (29) fixedly mounted on the outside of the steam duct (28), a driving end of the motor (29) extending into the interior of the steam duct (28), and a bevel gear set (32) connecting the driving end of the motor (29) and a rotating shaft (33).

10. Application of the steel plant steam recovery device according to any one of claims 1 to 9 in aerated concrete production, characterized in that: The following steps are involved: S1. Prepare aerated concrete slurry: mix iron tailings, cement, lime and desulfurized gypsum in a mass ratio of 60:12:23:5 to obtain a mixture, add 60% of water by mass to the mixture, add a foam stabilizer in an amount of 8% by mass of the water, mix well, add 0.06% of aluminum powder paste by mass of the mixture, mix well, and obtain aerated concrete slurry; S2, stirring and foaming; S3, pouring test mold; S4. Static curing: Place the cast aerated concrete in a static curing room for static curing at a temperature of 55°C. S5, demoulding the mold to form a blank; S6. Autoclave curing: placing the aerated concrete block in an autoclave curing room for curing; S7, drying in an oven to obtain a finished aerated concrete product; The static curing room and the autoclave curing room are both connected to the heat exchange component of the steam recovery device through pipelines, and the heat recovered by the steam recovery device is transmitted to the static curing room and the autoclave curing room.

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