Energy recovery system in non-continuous high-temperature liquid slag cooling process

Abstract

The utility model discloses an energy recovery system in a non-continuous high-temperature liquid slag cooling process. The energy recovery system comprises a continuous feeding track, a liquid slag pot, tunnel radiation heat exchange equipment and a controller, the tunnel radiation heat exchange equipment comprises a shell of a tunnel structure, a membrane type water cooling wall arranged on the inner wall face of the shell and a steam pocket arranged on the outer side of the shell, an upper outlet of the membrane type water cooling wall is connected with an inlet of the steam pocket, and a lower outlet of the steam pocket is connected with a lower inlet of the membrane type water cooling wall through a downcomer. The continuous feeding track comprises a main track and a plurality of branch tracks, a discharge port of each electric arc furnace is correspondingly provided with one branch track, and the tail ends of the branch tracks are converged to the front end of the main track; the main track penetrates through a shell inlet and outlet of the tunnel structure. And the controller is electrically connected with the continuous feeding track. The device can recover heat in the cooling process of the high-temperature liquid slag, is high in energy utilization rate and safety, is a continuous production process, and is stable and reliable.

Description

Technical Field

[0001] The utility model belongs to the field of energy recovery and utilization, in particular to an energy recovery system for a discontinuous high-temperature liquid slag cooling process. Background Art

[0002] The energy recovery process of the discontinuous high-temperature liquid slag cooling process serves the liquid slag produced by the electric arc furnace in the metallurgical and chemical industries, such as calcium carbide, ferrosilicon, industrial silicon furnaces, etc. So far, this type of slag is still cooled by natural cooling. In the production process, the charge is smelted to 1500-2200℃ by the electric arc furnace to generate high-temperature molten liquid, which then flows into the liquid slag pot from the discharge port. The pot is lifted to the ground of the cooling workshop by a bridge crane and a single clamp, cooled for several hours under natural ventilation conditions, and then enters the transportation link. This production process has high energy consumption, and the natural cooling process dissipates heat energy into the air, which not only wastes energy, but also forms a very high ambient temperature, resulting in a harsh working environment and safety risks.

[0003] At present, high-temperature liquid slag, as a product of the metallurgical and chemical industries, has high temperature and large output, and contains abundant waste heat that needs to be recovered. After the scientific and rational use of this part of heat energy, it can not only reduce thermal pollution and improve the safety of production operations, but also the recovered heat can reduce the production costs of enterprises and bring them economic benefits.

[0004] Most domestic manufacturers that deal with high-temperature liquid slag generally use natural air cooling to cool the high-temperature liquid slag after it comes out of the furnace. This treatment method does not recycle a large amount of sensible heat. A small number of manufacturers use induced draft fans to conduct convection heat exchange on the liquid slag to utilize the heat energy in the hot air, but due to the low heat capacity of air, the waste heat utilization efficiency of this process is not high, and the non-continuous production process has a great impact on the stability of energy utilization.

[0005] Chinese patent document with publication number CN116219092A discloses a slag cooling treatment device, which uses a gas-liquid water spray device and a cooling water spray device to perform initial and secondary cooling on the slag, and this treatment method causes waste of residual heat.

[0006] A Chinese patent document with publication number CN112063780A discloses a slag heat exchanger, which uses a conical container as a cooling chamber, the cooling chamber is fixed on a shell, the cooling chamber and the shell form a water chamber, the shell has a water inlet and a water outlet, and a slag discharge door is fixed on the shell through a door opening and closing device. The slag heat exchanger has a fast slag cooling speed and a good cooling effect, but it is inconvenient to operate and cannot be applied to automated production. Utility Model Content

[0007] The utility model provides an energy recovery system for a discontinuous high-temperature liquid slag cooling process, which can recover heat in the cooling process, has high energy utilization rate, high safety, and is a continuous production process, stable and reliable.

[0008] An energy recovery system for a discontinuous high-temperature liquid slag cooling process, suitable for liquid slag produced by an electric arc furnace, comprises a continuous feeding track, a liquid slag pot, a tunnel radiation heat exchange device and a controller that cooperate with each other;

[0009] The tunnel radiation heat exchange equipment comprises a shell of a tunnel structure, a membrane water-cooled wall arranged on the inner wall surface of the shell, and a steam drum arranged on the outer side of the shell, wherein the upper outlet of the membrane water-cooled wall is connected to an inlet of the steam drum, and the lower outlet of the steam drum is connected to the lower inlet of the membrane water-cooled wall through a downcomer;

[0010] The continuous feeding track includes a main track and a plurality of branch tracks. A branch track is arranged correspondingly below the discharge port of each electric arc furnace, and the end of each branch track converges to the front end of the main track; the main track passes through the shell entrance and exit of the tunnel structure;

[0011] The controller is electrically connected to the continuous feeding track and is used to control the main track and the branch track to transport the liquid slag pot.

[0012] Furthermore, the tunnel radiation heat exchange equipment also includes an upper header and a lower header, the upper outlet of the membrane water-cooled wall is connected to an inlet of the steam drum after passing through the upper header, and the downcomer is connected to the lower inlet of the membrane water-cooled wall after passing through the lower header.

[0013] The desalted water is heated to a steam-liquid mixed state through the membrane water-cooled wall through radiation heat exchange, and the steam-water separation is completed in the steam drum. The generated saturated steam is transported to the outside, and the boiler water in the steam drum is re-injected into the membrane water-cooled wall through the downcomer, realizing spontaneous continuous operation, safety and efficiency.

[0014] Furthermore, the membrane water-cooled wall is composed of a plurality of parallel thin tubes; the outlets of the plurality of parallel thin tubes are collected in an upper header, and the inlets are collected in a lower header.

[0015] Furthermore, the membrane water-cooled wall is arranged on the inner side wall and inner top surface of the shell of the tunnel structure, the inlet and outlet sides of the shell are sealed with steel plates, and the outside of the shell and the steel plate are provided with a thermal insulation layer.

[0016] Furthermore, the pot body of the liquid slag pot is in the shape of a truncated cone that is larger at the top and smaller at the bottom, and the pot body is provided with a slag cavity opening upward.

[0017] Furthermore, two notches are symmetrically arranged on the top of the pot body, and pot ears are installed in the two notches, and the outer walls of the pot ears are connected to hook blocks.

[0018] An energy recovery method for a discontinuous high-temperature liquid slag cooling process, using the above energy recovery system, comprising:

[0019] Each discharge port of the electric arc furnace discharges materials at intervals of 40-90 minutes, and each discharge lasts for 10-30 minutes;

[0020] The liquid slag is injected into the liquid slag pot below from the discharge port of the electric arc furnace. Under the control of the controller, the branch track transports the liquid slag pot filled with liquid slag to the main track, and then transports it to the tunnel radiation heat exchange equipment through the main track for radiation heat exchange; after the liquid slag is cooled to a certain temperature, it is sent out of the tunnel radiation heat exchange equipment through the main track;

[0021] Among them, the controller controls the moving speed and production sequence of different liquid slag pots on the continuous feeding track, so that the liquid slag produced by different arc furnaces can enter and exit the tunnel radiation heat exchange equipment almost continuously for radiation heat exchange.

[0022] Preferably, the controller controls the conveying speed of the main track so that each liquid slag pot stays inside the tunnel radiation heat exchange equipment for 1 to 3 hours.

[0023] Furthermore, in addition to controlling the moving speed of the liquid slag pot on the continuous feeding track, the controller can also be used to control the feed of desalted water in the drum and the delivery of saturated steam, making the entire process continuous and stable, and the process safe and efficient.

[0024] Compared with the prior art, the utility model has the following beneficial effects:

[0025] 1. Compared with the vast majority of processes that use natural air cooling to cool high-temperature liquid slag, the system of the utility model can effectively recycle and utilize a large amount of wasted energy; compared with a small number of processes that use convection heat exchange, the utility model overcomes the problem of low air heat capacity, uses desalted water to generate high-grade steam for utilization, and improves the efficiency of waste heat utilization; in addition, the utility model adjusts the discontinuous discharge process to a nearly continuous discharge process, thereby improving the stability of the overall process.

[0026] 2. The utility model focuses on recovering the waste heat of high-temperature liquid slag products in the metallurgical and chemical industries and making scientific and rational use of it. It can not only reduce thermal pollution and improve the safety of on-site production operations, but also improve the energy grade of slag waste heat, improve energy utilization efficiency, reduce production costs for enterprises, and bring economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the coordination between the liquid slag pot and the tunnel radiation heat exchange equipment in the utility model;

[0028] Figure 2 It is a schematic structural diagram of the liquid slag pot in the utility model. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0030] An energy recovery system for a discontinuous high-temperature liquid slag cooling process comprises a continuous feeding track, a liquid slag pot 1, a tunnel radiation heat exchange device and a controller that cooperate with each other.

[0031] like Figure 1 As shown, the tunnel radiation heat exchange equipment includes a shell of a tunnel structure, a membrane water-cooled wall 5 arranged on the inner wall of the shell, and a steam drum 2 arranged on the outer side of the shell. The upper outlet of the membrane water-cooled wall 5 is connected to an inlet of the steam drum 2 after passing through an upper header 6, and the lower outlet of the steam drum 2 is connected to the lower header 4 through a downcomer 3 and then connected to the lower inlet of the membrane water-cooled wall 5.

[0032] The main function of drum 2 is to separate water from steam. When the desalted water is heated to a vapor-liquid mixture through radiation heat exchange, the mixture enters drum 2 and the steam-water separation is completed inside drum 2. In this process, saturated steam is extracted for various industrial applications, and the boiler water in drum 2 is re-injected into the water-cooled wall through downcomer 3. This process realizes spontaneous continuous operation.

[0033] The upper header 6 is connected to the upper part of the membrane water-cooled wall 5 and is responsible for receiving and distributing the heat from the desalted water. The reasonable design of the upper header 6 can ensure that the heat is evenly distributed on the entire membrane water-cooled wall 5, thereby improving the thermal efficiency of the equipment.

[0034] The lower header 4 is connected to the lower part of the membrane water wall 5, and plays the role of collecting or distributing the steam-water working medium, reducing the transmission connection pipeline of the working medium. In addition, the lower header 4 also bears the role of supporting the entire membrane water wall 5 structure.

[0035] The membrane water wall 5 is the core part of the tunnel radiation heat exchange equipment, which is composed of multiple parallel thin tubes. The high-temperature slag transfers its heat energy to these thin tubes through radiation heat exchange, so that the water in the thin tubes is heated to a vapor-liquid mixed state. Therefore, the membrane water wall 5 plays multiple roles such as receiving heat, transferring heat and storing heat.

[0036] The downcomer 3 is an important component connecting the steam drum 2 and the membrane water-cooled wall 5, and is responsible for transporting the boiler water in the steam drum 2 to the membrane water-cooled wall 5. In this process, the boiler water is re-injected into the membrane water-cooled wall 5, realizing the spontaneous continuous operation of the equipment. The reasonable design of the downcomer 3 can ensure that the boiler water loses as little heat as possible during the transportation process, thereby improving the thermal efficiency of the entire equipment.

[0037] The continuous feeding track includes a main track and multiple branch tracks. A branch track is arranged below the discharge port of each electric arc furnace, and the end of each branch track converges to the front end of the main track; the main track passes through the shell entrance and exit of the tunnel structure; the controller is electrically connected to the continuous feeding track, and is used to control the main track and the branch track to transport the liquid slag pot 1.

[0038] like Figure 2 As shown, the pot body of the liquid slag pot 1 is in the shape of a truncated cone with a larger top and a smaller bottom, and the pot body is provided with a slag cavity 11 opening upward. Two notches are symmetrically arranged on the top of the pot body, and pot ears 12 are installed in both notches, and the outer wall of the pot ears 12 is connected to a hook block 13.

[0039] To verify the effect of the present invention, a specific example is given below for illustration.

[0040] In this embodiment, each electric arc furnace has three discharge ports, which are arranged at 120 degrees to each other. Each electric arc furnace discharges materials at intervals of 60 minutes, and each discharge lasts for 20 minutes. The three electric arc furnaces are grouped into one group, and the slag discharges of the three electric arc furnaces are collected on a main track through the corresponding branch tracks. The controller controls the continuous feed track to adjust the moving speed so that the three electric arc furnaces discharge materials in sequence, that is, after one electric arc furnace has finished discharging materials, the other one will immediately continue to discharge materials. Through such adjustments, even if the slag discharge sequence of each furnace is intermittent discharge, the three electric arc furnaces as a whole achieve nearly continuous discharge in the production process.

[0041] The liquid slag pot 1 used in this embodiment has a height of 898mm and an extension width of 1530mm. The pot body is in a truncated cone shape with a large top and a small bottom. In order to increase the overall radiation heat exchange area of ​​the slag, the height of the slag pot is reduced to 500mm, and the volume of each slag pot is approximately half of the original. Under the same output, the number of liquid slag pots 1 needs to be set to twice the original to meet normal discharge requirements. Therefore, under the same liquid slag output, the total radiation heat exchange area facing the top is expanded to twice the original area, which greatly improves the waste heat utilization efficiency, and at the same time, the continuity of the entire system is better.

[0042] The liquid slag is 1600℃ calcium carbide liquid with a production of 30t / h, which is continuously fed into the tunnel radiation heat exchange equipment through a continuous feeding track and divided into the liquid slag pot 2. Among them, the tunnel radiation heat exchange equipment is 2.73m wide, 4.8m high at the top, 25m long, and is coated with 30mm thick rock wool insulation material. The shell inlet and outlet of the tunnel structure are sealed with steel plates on both sides, and the outside is also coated with 30mm thick rock wool insulation material, leaving only a channel for the liquid slag pot 2 to enter and exit. The moving speed of the liquid slag pot 1 is controlled so that each pot stays in the tunnel for 2h. The calcium carbide liquid mainly exchanges heat with the membrane water-cooled wall in the equipment in the form of radiation. According to calculations, the surface temperature of the calcium carbide liquid at the outlet position is reduced to 400℃, which can produce 10.5t / h of 1.5MPa 200℃ saturated steam.

[0043] The controller in the utility model is used to control the moving speed of the liquid slag pot 1 on the track system, so as to cooperate with the main production process and improve the continuity of the system; it is used to control the desalted water supply system, so that the boiler can produce steam of qualified quality and avoid corrosion of the working medium; it is used to control the thermal system of the main equipment, so that the waste heat boiler can work normally and the entire process can be realized continuously, stably, safely and efficiently.

[0044] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy recovery system for the discontinuous high-temperature liquid slag cooling process, suitable for liquid slag produced by electric arc furnaces, It is characterized in that It includes a continuous feeding track, a liquid slag pot, a tunnel radiation heat exchange device and a controller that cooperate with each other; The tunnel radiation heat exchange equipment comprises a shell of a tunnel structure, a membrane water-cooled wall arranged on the inner wall surface of the shell, and a steam drum arranged on the outer side of the shell, wherein the upper outlet of the membrane water-cooled wall is connected to an inlet of the steam drum, and the lower outlet of the steam drum is connected to the lower inlet of the membrane water-cooled wall through a downcomer; The continuous feeding track includes a main track and a plurality of branch tracks. A branch track is arranged correspondingly below the discharge port of each electric arc furnace, and the end of each branch track converges to the front end of the main track; the main track passes through the shell entrance and exit of the tunnel structure; The controller is electrically connected to the continuous feeding track and is used to control the main track and the branch track to transport the liquid slag pot.

2. The energy recovery system for the discontinuous high-temperature liquid slag cooling process according to claim 1, It is characterized in that The tunnel radiation heat exchange equipment also includes an upper header and a lower header. The upper outlet of the membrane water-cooled wall is connected to an inlet of the steam drum after passing through the upper header, and the downcomer is connected to the lower inlet of the membrane water-cooled wall after passing through the lower header.

3. The energy recovery system for the discontinuous high-temperature liquid slag cooling process according to claim 2, It is characterized in that The membrane water-cooled wall is composed of a plurality of parallel thin tubes; the outlets of the plurality of parallel thin tubes are collected in an upper header, and the inlets are collected in a lower header.

4. The energy recovery system for the discontinuous high-temperature liquid slag cooling process according to claim 1, It is characterized in that The membrane water-cooled wall is arranged on the inner side wall and inner top surface of the shell of the tunnel structure. The inlet and outlet sides of the shell are sealed with steel plates. The shell and the steel plates are both provided with insulation layers.

5. The energy recovery system for the discontinuous high-temperature liquid slag cooling process according to claim 1, It is characterized in that The pot body of the liquid slag pot is in the shape of a truncated cone that is larger at the top and smaller at the bottom, and the pot body is provided with a slag cavity that opens upward.

6. The energy recovery system for the discontinuous high-temperature liquid slag cooling process according to claim 5, It is characterized in that The top of the pot body is symmetrically provided with two notches, pot ears are matched and installed in the two notches, and the outer walls of the pot ears are connected with hook blocks.

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