Molten steel slag sensible heat recovery method

Abstract

The invention relates to the field of sensible heat recovery methods, in particular to a molten steel slag sensible heat recovery method which comprises the following steps: feeding high-temperature molten steel slag into a tank heat exchanger, cooling the high-temperature molten steel slag in a manner of combining radiation heat exchange with conduction heat exchange, and meanwhile, cooling the high-temperature molten steel slag in a tank heat exchanger; in the cooling and condensing process, mechanical impact force is applied to the steel slag for crushing, so that granular medium-temperature solid steel slag and a first part of saturated steam are obtained; and the medium-temperature solid steel slag and the first part of saturated steam are fed into post-stage waste heat recovery equipment, sensible heat of the medium-temperature solid steel slag and the first part of saturated steam is further recovered to produce a final product, the final product is superheated steam, and meanwhile the medium-temperature solid steel slag is cooled to the target temperature. According to the embodiment of the invention, water is not contacted in the process of cooling and crushing the high-temperature molten steel slag, so that the problem that a large amount of dust-containing steam is generated by a water quenching method is avoided, the heat energy recovery efficiency is improved, and meanwhile, water resources are effectively saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sensible heat recovery method, in particular to a molten steel slag sensible heat recovery method. BACKGROUND

[0002] The existing steel slag treatment process does not recover the huge sensible heat resources of high-temperature molten steel slag, and the commonly used heat pouring, pool stewing, drum method and pressure or atmospheric roller pressure heat crushing process also consume a large amount of water resources, especially the roller pressure heat crushing process generates a large amount of dust-containing water vapor by spraying a large amount of water to the high-temperature molten steel slag for cooling, which greatly increases the dust removal workload of the system, the operation energy consumption is high, and the production cost of the enterprise is increased. SUMMARY

[0003] The purpose of the present application is to provide a molten steel slag sensible heat recovery method to solve the problems of consuming a large amount of water resources and generating a large amount of dust in the traditional high-temperature molten steel slag treatment method, high energy consumption and environmental pollution.

[0004] To solve the above technical problems, the present application specifically provides the following technical scheme:

[0005] A sensible heat recovery method of molten steel slag, comprising the following steps: a front-stage heat exchange step: sending high-temperature molten steel slag into a tank heat exchanger, cooling the high-temperature molten steel slag by a combination of radiation heat exchange and conduction heat exchange, and at the same time, applying mechanical impact force to the high-temperature molten steel slag in the cooling and condensation process to crush it, so as to obtain granular medium-temperature solid steel slag and a first part of saturated steam; a rear-stage waste heat recovery step: sending the medium-temperature solid steel slag and the first part of saturated steam into a rear-stage waste heat recovery device to further recover the sensible heat thereof to produce a final product, which is superheated steam, and cool the medium-temperature solid steel slag to a target temperature.

[0006] Further, the front-stage heat exchange step is performed by at least three tank heat exchangers operating in staggered peaks to ensure that the medium-temperature solid steel slag and the first part of saturated steam can be continuously and stably supplied to the rear-stage waste heat recovery device.

[0007] Further, the tank heat exchanger comprises a rotatable treatment tank, and a radiation heat exchanger and a crushing tooth fixedly arranged inside the treatment tank and not rotating synchronously with the treatment tank; the radiation heat exchanger is used to absorb the heat radiation of the high-temperature molten steel slag to produce the first part of saturated steam; and the crushing tooth is used to apply mechanical impact force to the high-temperature molten steel slag in the cooling and condensation process when the treatment tank rotates.

[0008] Further, the post-stage waste heat recovery device comprises a vertical heat exchange tower and a flue waste heat boiler, and the post-stage waste heat recovery step comprises: feeding the medium-temperature solid steel slag into the vertical heat exchange tower and making it exchange heat with low-temperature exhaust gas as the output of the flue waste heat boiler in countercurrent to obtain target-temperature steel slag and high-temperature exhaust gas; feeding the high-temperature exhaust gas and the first part of saturated steam into the flue waste heat boiler to produce the superheated steam.

[0009] Further, in the vertical heat exchange tower, the flow path of the medium-temperature solid steel slag is defined by alternately arranged positive taper guide vanes and inverted taper guide vanes from top to bottom to form a diffusion-converging spiral falling track, and the positive taper guide vanes and the inverted taper guide vanes are provided with circumferentially distributed long holes, so that the low-temperature exhaust gas flowing from bottom to top forms a multi-stage turbulent wind field to strengthen the turbulent mixing and heat exchange of gas and solid.

[0010] Further, the high-temperature exhaust gas discharged from the vertical heat exchange tower is subjected to at least one dust removal treatment before entering the flue waste heat boiler.

[0011] Further, the low-temperature exhaust gas discharged from the flue waste heat boiler is fed into the vertical heat exchange tower through a low-temperature exhaust gas conveying system comprising a circulating fan, and the pressure, flow or temperature of the exhaust gas entering the vertical heat exchange tower is controlled by a throttle valve and / or a cold air valve arranged in the low-temperature exhaust gas conveying system.

[0012] Further, the post-stage waste heat recovery device comprises a vertical waste heat boiler, the inside of the vertical waste heat boiler is provided with a steel slag flow channel capable of receiving medium-temperature solid steel slag and allowing it to flow naturally by gravity, a heat exchange flow channel surrounds the steel slag flow channel to make the working medium flowing in the heat exchange flow channel conductively exchange heat with the medium-temperature solid steel slag, and the heat exchange flow channel comprises a superheating section, an evaporation section and a heating section arranged in sequence along the steel slag flow channel; the post-stage waste heat recovery step comprises: the medium-temperature solid steel slag conductsively exchanges heat with the working medium flowing in the heat exchange flow channel in the steel slag flow channel to heat the working medium in the heating section, heat the working medium into a second part of saturated steam in the evaporation section, and heat the first part of saturated steam and the second part of saturated steam into the superheated steam in the superheating section after being combined.

[0013] Further, the heat exchange channel further comprises a gas-water separator, the gas-water separator comprising a water supplementing port, a liquid outlet, a gas-liquid mixture inlet and a gas outlet, the inlet of the superheating section being connected to the gas outlet of the gas-water separator and the saturated steam outlet of the tank-type heat exchanger, the inlet of the evaporation section being connected to the liquid outlet of the gas-water separator, the outlet of the evaporation section being connected to the gas-liquid mixture inlet of the gas-water separator, the inlet of the heating section being connected to a normal-temperature water source, and the outlet of the heating section being connected to the water supplementing port of the gas-water separator.

[0014] Further, the post-stage waste heat recovery step further comprises the following steps of circulating and supplementing the working medium: the external normal-temperature water enters the heating section, absorbs the heat of the middle-temperature solid steel slag tail part and is preheated into hot water, and is sent into the gas-water separator as the supplementing water; the water in the gas-water separator enters the evaporation section, absorbs the heat of the middle-temperature solid steel slag middle part and forms a gas-water mixture, the gas-water mixture returns to the gas-water separator for gas-liquid separation, and the separated water enters the evaporation section again to form an evaporation cycle; and the second part of the saturated steam is obtained by the gas-water separator.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] The present application provides a sensible heat recovery method of molten steel slag. The high-temperature steel slag does not contact water during the process of temperature reduction and crushing, thereby avoiding the problem of a large amount of dust-containing steam generated by water quenching. The high-temperature steel slag and the middle-temperature steel slag are treated in stages, thereby improving the heat energy recovery efficiency and the system adaptability. The sensible heat of the steel slag is effectively recovered while the steel slag is crushed at low energy consumption, thereby providing high-quality steam for enterprises, bringing additional economic benefits, and saving water resources. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can also be obtained from the provided drawings without creative labor.

[0018] Figure 1 The system diagram of the first embodiment of the present application;

[0019] Figure 2 The slag feeding working condition of the tank-type heat exchanger of the first embodiment of the present application;

[0020] Figure 3 The heat exchange working condition of the tank-type heat exchanger of the first embodiment of the present application;

[0021] Figure 4A tapping condition of the tank heat exchanger of the first embodiment of the present application;

[0022] Figure 5 A structural diagram of the vertical heat exchange tower of the first embodiment of the present application;

[0023] Figure 6 A system diagram of the second embodiment of the present application;

[0024] Figure 7 A structural diagram of the vertical waste heat boiler of the second embodiment of the present application;

[0025] The reference numerals in the drawings represent the following respectively:

[0026] 1 - tank heat exchanger; 11 - treatment tank; 12 - material passing port; 13 - cover door; 14 - horizontal rotary table; 15 - radiation heat exchanger; 16 - crushing tooth; 17 - chain plate conveyor; 18 - bucket elevator; 2 - vertical heat exchange tower; 21 - tower body; 22 - normal cone guide plate; 23 - inverted cone guide plate; 24 - long hole; 25 - hollow column; 3 - flue waste heat boiler; 31 - saturated steam delivery pipe; 32 - throttle valve; 33 - low temperature air pipe; 34 - circulating fan; 35 - cold air valve; 36 - high temperature air pipe; 37 - cyclone dust collector; 38 - metal filter drum dust collector; 4 - vertical waste heat boiler; 41 - superheating section; 42 - evaporation section; 43 - heating section; 44 - gas-water separator; 441 - water supplement port; 442 - liquid outlet; 443 - gas-liquid mixture inlet; 444 - gas outlet. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0028] In order to solve the problems of large water resource consumption and high operation energy consumption in the existing steel slag treatment process, the present application provides a sensible heat recovery device and sensible heat recovery method for molten steel slag.

[0029] (First embodiment, description of sensible heat recovery device and sensible heat recovery method)

[0030] Reference Figure 1, the sensible heat recovery device comprises a tank heat exchanger 1, a vertical heat exchange tower 2 and a flue waste heat boiler 3, the tank heat exchanger 1 is used for radiative heat exchange between water and high-temperature molten steel slag (above 1300℃) and cooling the high-temperature molten steel slag into broken granular medium-temperature solid steel slag (about 800℃), while generating saturated steam, the vertical heat exchange tower 2 guides the low-temperature waste gas to conduct convective heat exchange with the medium-temperature solid steel slag in the tower, so as to cool the medium-temperature solid steel slag to a target temperature, while generating high-temperature waste gas, and the high-temperature waste gas and the saturated steam are introduced into the flue waste heat boiler 3 to produce superheated steam, thereby realizing dry recovery of the sensible heat of the steel slag.

[0031] The target temperature is slightly higher than the temperature of the normal-temperature water input into the flue waste heat boiler 3.

[0032] The sensible heat recovery method comprises the following steps:

[0033] Step one, the high-temperature molten steel slag (above 1300℃) is sent into the tank heat exchanger 1, the tank heat exchanger 1 breaks and conducts water cooling heat exchange, so as to cool the high-temperature molten steel slag into small pieces of medium-temperature solid steel slag (about 800℃), while generating saturated steam.

[0034] Step two, the medium-temperature solid steel slag is sent into the vertical heat exchange tower 2 to flow naturally from top to bottom, and the low-temperature waste gas discharged from the flue waste heat boiler 3 is sent into the vertical heat exchange tower 2 to flow naturally from bottom to top, the medium-temperature solid steel slag conducts convective heat exchange with the low-temperature waste gas, the medium-temperature solid steel slag is reduced to the target temperature, and the low-temperature waste gas is heated to high-temperature waste gas.

[0035] Step three, the saturated steam generated in step one and the high-temperature waste gas generated in step two are introduced into the flue waste heat boiler 3 to produce superheated steam.

[0036] Preferably, the tank heat exchanger 1 in the sensible heat recovery device and the sensible heat recovery method has at least three, and multiple tank heat exchangers 1 staggered operation, so as to ensure that the saturated steam can be stably transported to the flue waste heat boiler 3, and at the same time, the medium-temperature solid steel slag can be stably transported to the vertical heat exchange tower 2.

[0037] (First embodiment, description of the tank heat exchanger 1)

[0038] Reference Figures 2 to 4 , the tank heat exchanger 1 comprises a treatment tank 11, a horizontal rotary table 14, a radiative heat exchanger 15 and a breaking tooth 16.

[0039] The treatment tank 11 is a rotatable horizontal cylindrical structure, used for containing high-temperature molten steel slag, the horizontal rotary table 14 is used for supporting and driving the treatment tank 11 to rotate around its own axis, and the peripheral wall of the treatment tank 11 is provided with a slag discharge port, and a openable and closable cover door 13 is installed on the slag discharge port, and the cover door 13 is opened when feeding and discharging.

[0040] When the steel slag is put into the inside of the treatment tank 11, the slag outlet is located at the top of the treatment tank 11; when the steel slag is treated in the inside of the treatment tank 11, the slag outlet swings back and forth at the top of the treatment tank 11 along with the reciprocating rotation of the treatment tank 11, and the slag outlet can be closed or not closed; when the slag is discharged, the slag outlet is located at the bottom of the treatment tank 11, so that the steel slag in the inside of the treatment tank 11 is discharged.

[0041] Preferably, a cooling water flow channel (not shown in the figure) is arranged in the interlayer of the wall surface of the treatment tank 11, which is used to circulate the cooling water to absorb the heat of the steel slag through heat conduction on one hand, and to protect the treatment tank 11 itself from being damaged by high temperature on the other hand; a high-temperature reflection layer (not shown in the figure) is arranged at the upper part of the inner wall of the treatment tank 11, which is used to reflect the heat radiation of the steel slag to the radiation heat exchanger 15.

[0042] The radiation heat exchanger 15 and the crushing teeth 16 are fixed in the inside of the treatment tank 11 by the support and do not rotate synchronously with the treatment tank 11.

[0043] The radiation heat exchanger 15 is used to absorb the heat radiation generated by the high-temperature molten steel slag in the inside of the treatment tank 11, one end of the radiation heat exchanger 15 is higher than the other end, and the normal temperature water is input into the inside of the radiation heat exchanger 15 from the lower end of the radiation heat exchanger 15, and the saturated steam formed after the normal temperature water absorbs heat is output from the higher end of the radiation heat exchanger 15.

[0044] The crushing teeth 16 can withstand the impact of the steel slag, and the crushing teeth 16 generate relative motion with the high-temperature molten steel slag in the inside of the treatment tank 11 when the treatment tank 11 performs the reciprocating rotary motion, and the mechanical impact force is applied to the high-temperature molten steel slag, so that the high-temperature molten steel slag naturally forms small granular particles in the process of condensing into medium-temperature solid steel slag.

[0045] Further, the cooling water flow channel is arranged in the inside of the crushing teeth 16 and the support connecting the frame and the crushing teeth 16 is provided with the cooling water flow channel communicated with the crushing teeth 16, so that the cooling water can circulate in the inside of the crushing teeth 16 to reduce the temperature of the crushing teeth 16 and ensure the normal work of the crushing teeth 16 in the high-temperature and impact environment.

[0046] The horizontal rotary table 14 includes two groups of bearing wheels, and the two groups of bearing wheels are respectively arranged at the two sides of the treatment tank 11, and each group of bearing wheels includes at least two coaxial bearing wheels, so that the treatment tank 11 can be stably supported by the bearing wheels.

[0047] The horizontal rotary table 14 further includes a motor (not shown in the figure) for driving the rotation of the bearing wheels or the treatment tank 11, so that the treatment tank 11 can rotate and reciprocate.

[0048] (First embodiment, description about the vertical heat exchange tower 2)

[0049] ReferenceFigure 5 The vertical heat exchange tower 2 comprises a tower body 21, the top of the tower body 21 is provided with a slag inlet and a high-temperature waste gas outlet, and the bottom of the tower body 21 is provided with a slag outlet and a low-temperature waste gas inlet.

[0050] The inside of the tower body 21 is provided with:

[0051] Alternately arranged from top to bottom are the positive taper guide plates 22 and the inverted taper guide plates 23, and the medium-temperature solid slag is driven by gravity to sequentially flow through the positive taper guide plates 22 and the inverted taper guide plates 23, forming a diffusion-converging spiral downward path of the medium-temperature solid slag, thereby prolonging the heat exchange journey of the medium-temperature solid slag.

[0052] The positive taper guide plates 22 and the inverted taper guide plates 23 are both provided with long holes 24 that are uniformly distributed in the circumferential direction, so that the low-temperature waste gas flowing from bottom to top forms a multi-stage turbulent wind field, thereby strengthening the turbulent gas-solid mixing and heat exchange.

[0053] The positive taper guide plates 22 are fixed by the hollow column 25 that is coaxially erected inside the tower body 21, the inside of the hollow column 25 is water-cooled, and the inverted taper guide plates 23 are rigidly connected with the inner wall of the tower body 21, thereby enhancing the thermal shock resistance of the tower body 21.

[0054] (First embodiment, description of the flue-type waste heat boiler 3)

[0055] Working principle of the flue-type waste heat boiler 3:

[0056] The flue-type waste heat boiler 3 uses the high-temperature waste gas generated by the vertical heat exchange tower 2 and the tank-type heat exchanger 1 as the main heat source to heat the boiler working water to generate steam and superheat it to generate superheated steam.

[0057] The flue-type waste heat boiler 3 also uses the saturated steam generated by the tank-type heat exchanger 1 to further heat it in the superheating section 41 of the flue-type waste heat boiler 3, thereby generating superheated steam.

[0058] (First embodiment, supplementary description of the sensible heat recovery device and the sensible heat recovery method)

[0059] Further, with reference to Figure 1 The sensible heat recovery device of the molten slag further comprises other components that facilitate the implementation of the sensible heat recovery method, such as:

[0060] Component 1, a conveying system connecting the discharge port of the tank-type heat exchanger 1 and the feeding port of the vertical heat exchange tower 2, comprising a chain plate conveyor 17 and a bucket elevator 18.

[0061] The chain plate conveyor 17 is used for receiving the 800 DEG C or so medium-temperature solid steel slag poured out by each tank heat exchanger 1 and conveying the solid steel slag to the feeding port of the bucket elevator 18, and the bucket elevator 18 is used for lifting the medium-temperature solid steel slag to the feeding port at the top of the vertical heat exchange tower 2.

[0062] The low-temperature waste gas conveying system connecting the air outlet of the flue waste heat boiler 3 and the air inlet of the vertical heat exchange tower 2 comprises a throttle valve 32, a low-temperature air pipe 33, a circulating fan 34 and a cold air valve 35.

[0063] The air outlet of the flue waste heat boiler 3, the throttle valve 32, the low-temperature air pipe 33, the circulating fan 34 and the air inlet of the vertical heat exchange tower 2 are sequentially connected, the circulating fan 34 is used for sucking the low-temperature waste gas from the inside of the flue waste heat boiler 3 through the low-temperature air pipe 33 and discharging the low-temperature waste gas to the air inlet of the vertical heat exchange tower 2, the throttle valve 32 is used for controlling the fluctuation of the air pressure and air flow in the low-temperature air pipe 33, and the cold air valve 35 is connected to the low-temperature air pipe 33 and the outdoor through a three-way pipe, and the cold air valve 35 is used for being actively opened to enable the circulating fan 34 to suck the low-temperature air from the outdoor into the inside of the vertical heat exchange tower 2 when the temperature of the low-temperature waste gas in the low-temperature air pipe 33 is too high.

[0064] The design effectively controls the pressure, flow and temperature of the gas entering the vertical heat exchange tower 2, so that the temperature of the steel slag output by the vertical heat exchange tower 2 is relatively stable.

[0065] The high-temperature waste gas conveying system connecting the air outlet of the vertical heat exchange tower 2 and the air inlet of the flue waste heat boiler 3 comprises a high-temperature air pipe 36, a cyclone dust collector 37 and a metal filter cartridge dust collector 38.

[0066] The air outlet of the vertical heat exchange tower 2, the high-temperature air pipe 36, the cyclone dust collector 37, the metal filter cartridge dust collector 38 and the air inlet of the flue waste heat boiler 3 are sequentially connected, and the high-temperature waste gas discharged from the vertical heat exchange tower 2 is discharged to the flue waste heat boiler 3 after being dedusted twice.

[0067] The saturated steam conveying pipe 31 connecting the saturated steam outlet of the tank heat exchanger 1 and the saturated steam inlet of the flue waste heat boiler 3 is used for moving the saturated steam by the pressure of the saturated steam.

[0068] The cooling water conveying system (not shown in the figure) connecting the cooling water inlet of the tank heat exchanger 1 comprises a water pump and a water storage tank.

[0069] The cooling water inlet, the water pump and the water storage tank are sequentially connected, the water tank is used for storing water, and the water pump is used for pumping water into the cooling water inlet.

[0070] The core advantages and innovation points of the embodiment are as follows:

[0071] Whole dry process: high-temperature molten steel slag does not contact water during the cooling and crushing process, avoiding the problem of a large amount of dust-containing steam generated by water quenching, and significantly reducing the investment and operating costs of environmental protection equipment.

[0072] Segmented processing and efficient recovery: high-temperature molten steel slag (high-grade heat energy) and medium-temperature solid steel slag (medium-low grade heat energy) are processed in stages, improving the heat recovery efficiency and system adaptability.

[0073] Continuous and stable energy output: through the intermittent coordinated operation of multiple tank heat exchangers 1 and the continuous operation of vertical heat recovery towers 2 and flue-type waste heat boilers 3, the conversion from intermittent slag to continuous and stable production of high-temperature superheated steam is realized, meeting the demand for stable heat sources for subsequent systems such as power generation.

[0074] Energy saving and economic benefits: while crushing steel slag at low energy consumption, effectively recovering the sensible heat of steel slag, providing high-quality steam for enterprises, bringing additional economic benefits, and saving water resources.

[0075] (Second embodiment, description of sensible heat recovery device and sensible heat recovery method)

[0076] The second embodiment differs from the first embodiment in that a vertical waste heat boiler 4 is used instead of the combination of a vertical heat recovery tower 2 and a flue-type waste heat boiler 3.

[0077] Reference Figure 6 , the sensible heat recovery device includes a tank heat exchanger 1 and a vertical waste heat boiler 4.

[0078] The tank heat exchanger 1 is used to radiate heat between water and high-temperature molten steel slag (above 1300°C), and cool it to medium-temperature solid steel slag (about 800°C) in the form of crushed particles, while generating the first part of saturated steam.

[0079] The vertical waste heat boiler 4 is internally provided with a steel slag flow channel and a heat exchange flow channel. The steel slag flow channel penetrates the vertical waste heat boiler 4 from top to bottom, so that the vertical waste heat boiler 4 can receive medium-temperature solid steel slag and allow it to flow naturally by gravity. The heat exchange flow channel surrounds the steel slag flow channel so that the working medium flowing inside it conducts heat exchange with the medium-temperature solid steel slag. The working medium includes the first part of steam and water, and the working medium forms superheated steam inside the heat exchange flow channel. The medium-temperature solid steel slag is discharged after being cooled to the target temperature.

[0080] The target temperature is slightly higher than the temperature of the normal temperature water input into the vertical waste heat boiler 4.

[0081] The discharge port of the tank heat exchanger 1 is connected with the feed port of the vertical waste heat boiler 4 through a chain plate conveyor 17 and a bucket elevator 18, wherein the chain plate conveyor 17 is used to receive the 800℃ or so medium-temperature solid steel slag poured out by each tank heat exchanger 1 and to convey the solid steel slag to the feed port of the bucket elevator 18, and the bucket elevator 18 is used to lift the medium-temperature solid steel slag to the feed port at the top of the vertical waste heat boiler 4.

[0082] Specifically, referring to Figure 7 , the heat exchange flow channel comprises, from top to bottom, a superheating section 41, an evaporation section 42 and a heating section 43, and a gas-water separator 44, and the superheating section 41, the evaporation section 42 and the heating section 43 adopt water-cooled walls.

[0083] The gas-water separator 44 comprises a water supplement port 441, a liquid outlet 442, a gas-liquid mixture inlet 443 and a gas outlet 444, the inlet of the superheating section 41 is connected with the gas outlet 444 of the gas-water separator 44 and the saturated steam outlet of the tank heat exchanger 1, the inlet of the evaporation section 42 is connected with the liquid outlet 442 of the gas-water separator 44, the outlet of the evaporation section 42 is connected with the gas-liquid mixture inlet 443 of the gas-water separator 44, and the inlet of the heating section 43 is connected with a normal-temperature water source, and the outlet of the heating section 43 is connected with the water supplement port 441 of the gas-water separator 44.

[0084] The sensible heat recovery method comprises the following steps:

[0085] Step one, normal-temperature water preheating and supplement: the external normal-temperature water enters the heating section 43 located at the bottom of the vertical waste heat boiler 4, is preheated into hot water by absorbing the heat of the tail part of the solid steel slag, and then sequentially passes through the outlet of the heating section 43, the water supplement port 441 and enters the gas-water separator 44 as the make-up water of the whole circulating system.

[0086] Step two, evaporation circulation: the water in the gas-water separator 44 enters the evaporation section 42 through the liquid outlet 442, boils to form a gas-water mixture by absorbing the heat of the middle part of the solid steel slag in the evaporation section 42, and then sequentially passes through the outlet of the evaporation section 42, the gas-liquid mixture inlet 443 and returns to the gas-water separator 44, the gas and liquid phases in the separator are separated, the separated liquid water re-enters the evaporation section 42 through the water outlet, and an independent and continuous evaporation circulation is formed.

[0087] Step three, steam convergence and superheating: the second part of the saturated steam separated from the gas-water separator 44 is led out through the gas outlet 444, then converges with the first part of the saturated steam generated by the tank heat exchanger at the inlet of the superheating section 41 at the top of the vertical waste heat boiler 4, and the mixed saturated steam enters the superheating section 41, exchanges heat with the top solid steel slag for the last time, is heated into superheated steam with higher heat energy, and is output as the final product.

[0088] The above examples are only exemplary embodiments of the present application and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements are also considered as falling within the protection scope of the embodiments of the present application.

Claims

1. A sensible heat recovery method of molten steel slag, characterized by, The method comprises the following steps: a pre-stage heat exchange step: sending high-temperature molten steel slag into a tank heat exchanger, cooling the high-temperature molten steel slag by a combination of radiation heat exchange and conduction heat exchange, and applying mechanical impact force to the high-temperature molten steel slag during the cooling and condensation process to break it, thereby obtaining granular medium-temperature solid steel slag and a first portion of saturated steam; a post-stage waste heat recovery step: sending the medium-temperature solid steel slag and the first portion of saturated steam into a post-stage waste heat recovery device to further recover the sensible heat thereof to produce a final product, which is superheated steam, and cool the medium-temperature solid steel slag to a target temperature.

2. The sensible heat recovery method according to claim 1, wherein the pre-stage heat exchange step is performed by at least three tank heat exchangers that are operated in staggered mode to ensure that the medium-temperature solid steel slag and the first portion of saturated steam can be continuously and stably supplied to the post-stage waste heat recovery device.

3. The sensible heat recovery method according to claim 1, wherein the tank heat exchanger comprises a rotatable treatment tank, and a radiation heat exchanger and breaking teeth fixedly arranged inside the treatment tank and not rotating synchronously with the treatment tank; the radiation heat exchanger is used to absorb the thermal radiation of the high-temperature molten steel slag to produce the first portion of saturated steam; the breaking teeth are used to apply mechanical impact force to the high-temperature molten steel slag during the cooling and condensation process when the treatment tank is rotating.

4. The sensible heat recovery method according to any one of claims 1-3, wherein the post-stage waste heat recovery device comprises a vertical heat exchange tower and a flue waste heat boiler, and the post-stage waste heat recovery step comprises: sending the medium-temperature solid steel slag into the vertical heat exchange tower and making it exchange heat with low-temperature exhaust gas as the output of the flue waste heat boiler in a counter-flow manner to obtain target-temperature steel slag and high-temperature exhaust gas; sending the high-temperature exhaust gas and the first portion of saturated steam into the flue waste heat boiler together to produce the superheated steam.

5. The sensible heat recovery method according to claim 4, wherein in the vertical heat exchange tower, the flow path of the medium-temperature solid steel slag is defined by alternately arranged positive taper guide vanes and inverted taper guide vanes from top to bottom, thereby forming a diffusion-convergence type spiral falling trajectory, and the positive taper guide vanes and the inverted taper guide vanes are provided with circumferentially distributed long holes, so that the low-temperature exhaust gas flowing from bottom to top forms a multi-stage turbulent wind field to intensify the gas-solid turbulent mixing and heat exchange.

6. The sensible heat recovery method according to claim 4, wherein the high-temperature exhaust gas discharged from the vertical heat exchange tower is subjected to at least one dust removal treatment before entering the flue waste heat boiler.

7. The sensible heat recovery method according to claim 4, wherein the low-temperature exhaust gas discharged from the flue waste heat boiler is sent into the vertical heat exchange tower through a low-temperature exhaust gas conveying system comprising a circulating fan, and the pressure, flow rate or temperature of the exhaust gas entering the vertical heat exchange tower is controlled by a throttle valve and / or a cold air valve arranged in the low-temperature exhaust gas conveying system.

8. The sensible heat recovery method according to any one of claims 1-3, wherein The post-stage waste heat recovery device comprises a vertical waste heat boiler, an internal steel slag flow channel capable of receiving the medium-temperature solid steel slag and allowing it to flow naturally by gravity is arranged in the vertical waste heat boiler, a heat exchange flow channel surrounds the steel slag flow channel so that the working medium flowing in the heat exchange flow channel conducts heat exchange with the medium-temperature solid steel slag, and the heat exchange flow channel comprises a superheating section, an evaporation section and a heating section arranged in sequence along the steel slag flow channel; The post-stage waste heat recovery step comprises: the medium-temperature solid steel slag conducts heat exchange with the working medium flowing in the heat exchange flow channel in the steel slag flow channel, so that the working medium is heated in the heating section, the working medium is heated into the second part of saturated steam in the evaporation section, and the first part of saturated steam and the second part of saturated steam are combined and heated into the superheated steam in the superheating section.

9. The sensible heat recovery method according to claim 8, wherein, The heat exchange flow channel further comprises an air-water separator, the air-water separator comprises a water supplementing port, a liquid outlet, an air-liquid mixture inlet and a gas outlet, the inlet of the superheating section is connected with the gas outlet of the air-water separator and the saturated steam outlet of the tank-type heat exchanger, the inlet of the evaporation section is connected with the liquid outlet of the air-water separator, the outlet of the evaporation section is connected with the air-liquid mixture inlet of the air-water separator, the inlet of the heating section is connected with a normal-temperature water source, and the outlet of the heating section is connected with the water supplementing port of the air-water separator.

10. The sensible heat recovery method according to claim 9, wherein, The post-stage waste heat recovery step further comprises the following steps of circulating and supplementing the working medium: The external normal-temperature water enters the heating section, absorbs the heat of the tail part of the medium-temperature solid steel slag and is preheated into hot water, and is sent into the air-water separator as the supplementing water; The water in the air-water separator enters the evaporation section, absorbs the heat of the middle part of the medium-temperature solid steel slag and forms an air-water mixture, the air-water mixture returns to the air-water separator for air-liquid separation, and the separated water enters the evaporation section again to form an evaporation cycle; The second part of saturated steam is obtained by the air-water separator.

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