Blast furnace slag flushing water lack steam dewhitening treatment and water saving system and method

Abstract

The present invention discloses a de-whitening treatment and water-saving system and method for blast furnace slag washing water spent steam. The system cools down the slag washing water spent steam, precipitates a large amount of water, reduces the moisture content in the slag washing water spent steam, thereby reducing white smoke or no white smoke during discharge. The precipitated water also carries dust, sulfur dioxide (SO2), nitrogen oxides (NO X ) and other pollutants, thereby further reducing the toxicity of the exhaust gas; the system is provided with a thermal mass dewhitening device, a spray assembly and a heat exchange tube are arranged inside it, and cooling is carried out by a combination of water cooling and air cooling. A collecting tank is arranged at its bottom to fully recycle the spray water and cooling water. After purification and sedimentation, the water is continued to be used as slag flushing water and spray water, thereby improving the utilization efficiency of water resources, saving water and reducing emissions.

Description

Technical Field

[0001] The invention relates to equipment and methods in the field of energy conservation and environmental protection, and in particular to a system and method for descaling and water-saving of blast furnace slag flushing water and deficient steam. Background Art

[0002] In the field of metallurgical production, in recent years, with the country's strict requirements on energy conservation, emission reduction and emission indicators, all walks of life have continuously taken measures to research new technologies, develop new processes, manufacture new equipment, and actively install and put them into use. After several years of efforts, some enterprises have met the national emission standards for dust, SO2, sewage and other emission indicators, which has greatly improved the environment.

[0003] However, there are other problems that need to be solved in the current industrial production. For example, when the slag water is insufficient to flush the blast furnace of the steel enterprise, a long white dragon will appear, also known as white smoke. The longer the white dragon is, the colder the area is. These white smokes have seriously damaged the urban landscape, affected the visibility of surrounding traffic, and caused serious pollution to the atmosphere. After analysis, it is known that the main component of these white smokes is water vapor, which also contains certain dust pollutants, sulfur dioxide (SO2), nitrogen oxides (NO X ), etc. These white smokes are also a cause of smog, so in recent years, there are more and more regulations and requirements on removing white smoke;

[0004] In addition, the water content in the white smoke is relatively high, and direct discharge into the air will inevitably lead to an increase in water consumption in the steel plant. If it can be recovered and recycled, it will not only save a lot of water resources, but also reduce the production costs of the enterprise.

[0005] Due to the above reasons, the inventors studied the composition, causes and changing patterns of white smoke at different temperatures, and found that the temperature of the exhausted steam from the slag flushing water is above 95°C when it escapes from the slag ditch, and the temperature is around 85°C when it is discharged from the chimney, and it still contains a large amount of water. On this basis, combined with the information such as the white smoke emission scale and white smoke composition of each factory, a system and method that can solve the above problems were designed. Summary of the invention

[0006] In order to overcome the above problems, the inventors have conducted intensive research and designed a system and method for de-whitening and water-saving of blast furnace slag flushing water exhaust steam. The system cools the slag flushing water exhaust steam from 95°C in the slag ditch to 52°C before discharging it. During the cooling process, a large amount of water is precipitated from the slag flushing water exhaust steam, thereby reducing the moisture content in the slag flushing water exhaust steam, so that the white smoke when the slag flushing water exhaust steam is discharged is reduced or eliminated. The precipitated water also carries dust, sulfur dioxide (SO2), nitrogen oxides (NO X) and other pollutants, thereby further reducing the toxicity of the exhaust gas; a thermal mass dewhitening device is provided in the system, a spray assembly and a heat exchange tube are arranged inside the system, and cooling is performed by a combination of water cooling and air cooling. A liquid collecting tank is arranged at the bottom of the system to fully recycle the spray water and cooling water, and the water is continuously used as slag flushing water and spray water after being treated by purification and sedimentation, thereby improving the utilization efficiency of water resources, saving water, and reducing emissions, thereby completing the present invention.

[0007] Specifically, the purpose of the present invention is to provide a blast furnace slag flushing water exhaust steam dewhitening treatment and water saving system, the system comprises a slag flushing water exhaust steam outlet pipe 3, one end of which is located above the slag ditch 1, and the other end of which is connected to the thermal mass dewhitening device base 5;

[0008] The slag flushing water spent steam 6 in the slag ditch 1 enters the thermal mass desulphurizer base 5 through the slag flushing water spent steam outlet pipe 3;

[0009] The base 5 of the thermal mass desulphurizer is provided with a cavity for accommodating slag flushing water and steam 6.

[0010] A thermal mass deoxidizer body 8 communicating with the cavity is arranged on the top of the thermal mass deoxidizer base 5.

[0011] The slag flushing water spent steam 6 is cooled down in the process of moving upward in the thermal mass deoxidizer body 8 , and the water vapor therein condenses into liquid and flows back into the thermal mass deoxidizer base 5 .

[0012] A spray assembly 7 is further provided in the thermal mass dewhitening device base 5 , which is used to spray cooling water into the cavity in the thermal mass dewhitening device base 5 to cool the slag flushing water and exhausted steam 6 therein.

[0013] Wherein, a cyclone fan 2 is arranged on the slag flushing water and exhausted steam outlet pipe 3, which is used to continuously lead the slag flushing water and exhausted steam 6 from the slag ditch 1 to the thermal mass descaling device base 5;

[0014] Preferably, a pressure flow meter 4 is further provided on the slag flushing water exhausted steam outlet pipe 3 to monitor and record the amount of the slag flushing water exhausted steam 6 introduced.

[0015] Among them, a heat exchange tube 21 is arranged inside the thermal mass dewhitener body 8, and the slag washing water exhaust steam 6 in the thermal mass dewhitener base 5 moves upward inside the heat exchange tube 21 to the top of the thermal mass dewhitener body 8. In this process, the water vapor condenses into liquid and flows back to the thermal mass dewhitener base 5 along the inner wall of the heat exchange tube 21.

[0016] Among them, a tube sheet 22 is arranged inside the thermal mass deoxidizer body 8 near the thermal mass deoxidizer base 5, through which the heat exchange tube 21 is fixed and the slag flushing water exhaust steam 6 is blocked to prevent the slag flushing water exhaust steam 6 from escaping from the outside of the heat exchange tube 21 to the top of the thermal mass deoxidizer body 8.

[0017] Among them, a cold air connecting pipe 12 is arranged on the lower side of the thermal mass dewhitening device body 8, and cold air is injected into the thermal mass dewhitening device body 8 through the cold air connecting pipe 12. The cold air moves upward along the outside of the heat exchange tube 21 and absorbs the heat carried by the slag flushing water exhaust steam 6 in the heat exchange tube.

[0018] A dry mixed gas induced draft fan 9 is arranged on the top of the thermal mass deoxidizer body 8, and the dry mixed gas induced draft fan 9 sucks the slag flushing water exhausted steam 6 inside the heat exchange tube 21 and the cold air outside the heat exchange tube 21.

[0019] The system further includes a spray pump 17 disposed on the ground, wherein the spray pump 17 is connected to the spray assembly 7 via a spray pipeline 16 to provide cooling water for the spray assembly 7 .

[0020] The system further includes a cold air blower 15 disposed on the ground, wherein the cold air blower 15 is connected to the cold air connecting pipe 12 through a cold air pipe 14 to provide cold air to the cold air connecting pipe 12;

[0021] Preferably, the system further comprises a cold air duct support 13 for supporting the cold air duct 14 .

[0022] The present invention also provides a method for dewhitening and water-saving of exhausted steam from slag flushing in a blast furnace, characterized in that in the method, the exhausted steam from slag flushing in a blast furnace is dewhitened and water-saving treated by the system as described above.

[0023] The beneficial effects of the present invention include:

[0024] (1) The blast furnace slag washing water exhaust steam dewhitening treatment and water-saving system provided by the present invention has a simple structure, a small footprint, water and energy saving, easy maintenance, reliable operation, and low production and operation costs, and can achieve the purpose of reducing or dewhitening the exhaust steam emission of blast furnace slag washing water;

[0025] (2) The blast furnace slag flushing water exhaust steam dewhitening treatment and water saving system provided by the present invention can further reduce the emission of pollutants, making the pollutant emission amount far lower than the national standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the overall structure of a blast furnace slag flushing water deficient steam desulphurization treatment and water saving system according to a preferred embodiment of the present invention is shown;

[0027] Figure 2 A schematic structural diagram of a cross-section of a thermal mass deoxidizer according to a preferred embodiment of the present invention is shown;

[0028] Figure 3 A top view of a thermal mass deoxidizer according to a preferred embodiment of the present invention is shown;

[0029] Figure 4 A schematic diagram of the structure of a heat exchange tube with spiral grooves inside according to a preferred embodiment of the present invention is shown;

[0030] Figure 5 A schematic structural diagram of a spray assembly according to a preferred embodiment of the present invention is shown.

[0031] Description of Figure Numbers:

[0032] 1-Slag ditch

[0033] 2- Cyclone fan

[0034] 3-Slag flushing water exhaust steam outlet pipe

[0035] 4-Pressure flow meter

[0036] 5- Thermal mass debleaching device base

[0037] 6-Slag flushing water lacks steam

[0038] 7-Spray assembly

[0039] 71-Nozzle

[0040] 72-Nozzle

[0041] 8-Thermal dewhitening device body

[0042] 9-Dry Mixed Air Induced Draft Fan

[0043] 10-Dry Mixture

[0044] 11-Temperature flow meter

[0045] 12-Cold air connecting duct

[0046] 13-Cold air duct bracket

[0047] 14-Cold air duct

[0048] 15-Cold air blower

[0049] 16-Spray pipe

[0050] 17-Spray pump

[0051] 18-Lined bone plate

[0052] 19-Framework Design

[0053] 20-Fixed plate

[0054] 21-Heat exchange tube

[0055] 22-Tube sheet

[0056] 23-Sewage outlet DETAILED DESCRIPTION

[0057] The present invention will be further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present invention will become more clear and distinct.

[0058] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0059] According to the blast furnace slag flushing water lack steam dewhitening treatment and water saving system provided by the present invention, Figure 1 As shown in the figure, the system includes a slag flushing water and exhausted steam outlet pipe 3, one end of which is located above the slag ditch 1, and the other end of which is connected to the thermal mass desulphurizer base 5; the height difference between the end of the slag flushing water and exhausted steam outlet pipe 3 located above the slag ditch 1 and the horizontal flow channel in the slag ditch is 1 to 2 meters, and the slag flushing water and exhausted steam rising from the slag ditch escapes upward and enters the slag water and exhausted steam outlet pipe 3;

[0060] The slag flushing water spent steam 6 in the slag ditch 1 enters the thermal mass desulphurizer base 5 through the slag flushing water spent steam outlet pipe 3;

[0061] The base 5 of the thermal mass desulphurizer is provided with a cavity for accommodating slag flushing water and steam 6.

[0062] A thermal mass deoxidizer body 8 communicating with the cavity is arranged on the top of the thermal mass deoxidizer base 5.

[0063] The slag flushing water spent steam 6 is cooled down in the process of moving upward in the thermal mass deoxidizer body 8 , and the water vapor therein condenses into liquid and flows back into the thermal mass deoxidizer base 5 .

[0064] In the steelmaking and other fields, a large amount of high-temperature slag is produced. In the prior art, it is treated by a water quenching slag process, that is, the slag is washed with water. The water for washing the slag is the slag washing water described in this application. After washing the slag, the temperature of the slag washing water increases, and part of the slag washing water is vaporized into a gaseous state, which is dissipated into the air and then condensed into water mist, thereby obtaining the slag washing water-lacking steam described in this application.

[0065] The slag ditch described in the present application is a commonly used equipment component in the fields of steelmaking, etc. The steel slag produced by steelmaking is regularly discharged / dumped into the slag ditch, and the steel slag is washed with water in the slag ditch. The slag ditch already available in the prior art can be connected to the blast furnace slag flushing water, exhausted steam, dewhitening treatment and water-saving system provided in the present application, and the present application does not make any special limitation on this.

[0066] Preferably, a liquid collecting tank is provided at the lower end of the cavity, in which condensed water after condensation of the spray water and the slag flushing water exhaust steam 6 is collected;

[0067] Preferably, the thermal mass dewhitening device body 8 and the thermal mass dewhitening device base 5 together constitute the thermal mass dewhitening device, which is also the core component of the device and method. The height of the thermal mass dewhitening device is generally about 12 meters. The work during actual installation is mainly to fix the thermal mass dewhitening device near the slag ditch, and then connect the slag ditch 1 through the slag flushing water exhaust steam outlet pipe 3, connect the liquid collecting tank with the water treatment equipment and the spray assembly and related equipment, and then set the cold air connecting pipe 12. Preferably, a spray assembly 7 is also provided in the thermal mass dewhitening device base 5, which is used to spray cooling water into the cavity in the thermal mass dewhitening device base 5 to cool the slag flushing water exhaust steam 6 therein. The temperature of the slag flushing water exhaust steam when entering the thermal mass dewhitening device base 5 is about 95 degrees, which is reduced to about 65-80 degrees after being sprayed by the spray assembly 7, and still has a high water content. When entering the subsequent air cooling link, a large amount of condensed water will precipitate. The slag flushing water exhausted steam mentioned in the present application refers to the gas containing saturated steam exhausted after the slag ditch is flushed with water. After multiple treatments are performed on the gas, it is still called slag flushing water exhausted steam.

[0068] The cooling water can be the water to be used for slag flushing, and its temperature can be room temperature. The spraying water enters the liquid collecting tank at the lower end of the cavity after spraying, and is mixed with the condensed water after the condensation of the slag flushing water exhaust steam 6 and then discharged to the outside of the thermal mass dewhitening device. After sedimentation, filtration, pH adjustment and other treatments, it can be used for slag flushing or spraying again, thereby realizing the continuous recycling of water resources. The specific water treatment procedure can be selected and set according to the factory and mine environment where the equipment is located and the composition of industrial raw materials, and this is not particularly limited in the present application.

[0069] Through actual monitoring, it is known that the condensed water returning from the heat exchange tubes carries a large amount of pollutant impurities. The subsequent water treatment process is mainly to remove the pollutant impurities mixed in the water. This also shows that the blast furnace slag water exhaust steam de-whitening treatment and water-saving system can not only de-whiten and save water, but also further reduce pollutant emissions.

[0070] Preferably, the system further comprises a spray pump 17 disposed on the ground, wherein the spray pump 17 is connected to the spray assembly 7 via a spray pipeline 16 to provide cooling water for the spray assembly 7 .

[0071] The spray pipeline 16 is a soft pipeline with good sealing performance, which can achieve the above-mentioned function of circulating cooling water. It can be prepared by using existing pipelines in the prior art, and the present application does not make any special limitation on this.

[0072] The spray pump 17 can be any existing pump in the art, as long as it can achieve the above functions, and the present application does not impose any particular limitation on this.

[0073] More preferably, the treated circulating water is extracted by the spray pump 17 and provided to the spray assembly 7 as cooling water, that is, the spray pump 17 is connected to the circulating water treatment system.

[0074] In a preferred embodiment, a cyclone fan 2 is provided on the slag flushing water and exhausted steam outlet pipe 3, which is used to continuously lead the slag flushing water and exhausted steam 6 from the slag ditch 1 to the thermal mass descaling device base 5;

[0075] The cyclone fan can be any existing fan in the art, as long as it can achieve the above functions, and this application does not make any special limitation on this.

[0076] Preferably, a pressure flow meter 4 is also provided on the slag flushing water and exhausted steam outlet pipe 3 to monitor and record the amount of the slag flushing water and exhausted steam 6 introduced;

[0077] The pressure flow meter can be a pressure flow meter already available in the art, as long as it can achieve the above functions, and this application does not impose any particular limitation on this.

[0078] Preferably, a plurality of slag flushing water and exhausted steam outlet pipes 3 are provided, and the connection ports of the slag flushing water and exhausted steam outlet pipes 3 and the slag ditch are arranged at different positions of the slag ditch, so as to lead out as much slag flushing water and exhausted steam from the slag ditch as quickly as possible.

[0079] At least one cyclone fan 2 is provided on each of the slag flushing water and exhausted steam outlet pipes 3;

[0080] A conical wide mouth is provided at the end of the slag flushing water and exhausted steam outlet pipe 3 connected to the slag ditch 1, so as to increase the circulation efficiency of the slag flushing water and exhausted steam.

[0081] In a preferred embodiment, a heat exchange tube 21 is provided inside the thermal mass dewhitener body 8, and the slag washing water exhaust steam 6 in the thermal mass dewhitener base 5 moves upward inside the heat exchange tube 21 to the top of the thermal mass dewhitener body 8. During this process, the water vapor condenses into liquid and flows back to the thermal mass dewhitener base 5 along the inner wall of the heat exchange tube 21.

[0082] The heat exchange tubes 21 are provided in plurality, and the plurality of heat exchange tubes are densely arranged and parallel to each other. Preferably, the size standards of the heat exchange tubes are substantially the same, and the inner diameter thereof is 70 to 90 mm, and more preferably 80 mm. A certain gap is left between two adjacent heat exchange tubes so that cold air can pass through the gap and take away the heat carried by the slag flushing water and exhausted steam 6 in the heat exchange tube to complete the heat exchange.

[0083] Preferably, a tube sheet 22 is provided inside the thermal mass dewhitener body 8 near the thermal mass dewhitener base 5, through which the heat exchange tube 21 is fixed and the slag flushing water exhaust steam 6 is blocked to prevent the slag flushing water exhaust steam 6 from escaping from the outside of the heat exchange tube 21 to the top of the thermal mass dewhitener body 8. That is, the slag flushing water exhaust steam 6 escaping upward from the thermal mass dewhitener base 5 is blocked by the tube sheet 22 and can only continue to escape upward after entering the heat exchange tube 21.

[0084] The tube sheet described in the present application includes a circular or square metal plate, on which a heat exchange tube is penetrated. The metal plate and the heat exchange tube are fixedly connected by expansion joint and / or welding. The heat exchange tube is fixed by the tube sheet, and the metal plate and the heat exchange tube are sealed without gaps, so as to prevent the slag flushing water and exhausted steam below the tube sheet from escaping to above the tube sheet through the gaps.

[0085] Preferably, a cold air connecting pipe 12 is provided on the lower side of the thermal mass dewhitening device body 8, and cold air is injected into the thermal mass dewhitening device body 8 through the cold air connecting pipe 12. The cold air moves upward along the outside of the heat exchange tube 21 and absorbs the heat carried by the slag flushing water exhaust steam 6 in the heat exchange tube.

[0086] Preferably, the system also includes a cold air blower 15 arranged on the ground, and the cold air blower 15 is connected to the cold air connecting duct 12 through a cold air duct 14 to provide cold air for the cold air connecting duct 12; the cold air can be ordinary outdoor air and does not need to be specially treated. In the summer when the outdoor temperature is high, the working power of the cold air blower 15 can be appropriately increased, and in the winter when the outdoor temperature is low, the working power of the cold air blower 15 can be appropriately reduced.

[0087] The cold air blower can be any existing blower in the art, as long as it can achieve the above functions, and this application does not make any special limitation on this.

[0088] Preferably, the system further comprises a cold air duct support 13 for supporting the cold air duct 14. The cold air duct support 13 is as follows: Figure 1 As shown in , one end of the cold air duct 14 is supported, and the other end of the cold air duct 14 stands on the ground, and the whole body is made of cross-connected steel.

[0089] The air duct can be made of existing ducts in the art, and can be a metal duct or a soft duct such as a plastic duct, as long as it can achieve the above functions, and this application does not make any special limitations on this.

[0090] The temperature of the cold air is substantially the same as the outdoor air temperature. After entering the thermal mass de-whitening device body 8, due to the high temperature of the slag flushing water exhaust steam in the heat exchange tube, generally about 65 to 80 degrees, the heat exchange tube itself has excellent thermal conductivity. The cold air absorbs the heat transferred from the heat exchange tube, and its own temperature gradually rises. The temperature of the slag flushing water exhaust steam in the heat exchange tube gradually decreases, and the water vapor condenses into water droplets, which slide along the inner wall of the heat exchange tube into the liquid collecting tank.

[0091] In the present application, two cooling and lowering schemes, water cooling and air cooling, are provided for the slag flushing water exhausted steam by spraying cooling water through a spray component and providing cold air with a cold air blower. While cooling the slag flushing water exhausted steam, the condensed water is collected. The lower the temperature of the slag flushing water exhausted steam when it is discharged, the lower the water content therein. Due to limited conditions, when the temperature of the slag flushing water exhausted steam drops to about 50 degrees, the cost of continuing to cool it down is too high, and when the temperature is below 50 degrees, the water content that can be precipitated by continuing to cool it down is also getting less and less. Therefore, discharging the slag flushing water exhausted steam when it is cooled to about 50-54 degrees is the most cost-effective solution, which can not only achieve the purpose of no white smoke or less white smoke, but also recycle a large amount of water resources and further reduce the content of pollutants discharged.

[0092] Preferably, a drain port 23 is provided above the tube sheet 22. After the cold air enters the thermal mass deoxidizer body 8, as the working time continues, some pollutants such as condensed water and dust particles will gradually fall back and accumulate on the tube sheet, so it is necessary to clean the tube sheet regularly, that is, to discharge the pollutants on the tube sheet to the outside of the thermal mass deoxidizer body 8 through the drain port 23.

[0093] In a preferred embodiment, a dry mixed gas induced draft fan 9 is provided on the top of the thermal mass deoxidizer body 8, and the dry mixed gas induced draft fan 9 sucks the slag flushing water exhausted steam 6 inside the heat exchange tube 21 and the cold air outside the heat exchange tube 21.

[0094] The dry mixed air induced draft fan may be any existing fan in the art, as long as it can achieve the above functions, and this application does not impose any special limitation on this.

[0095] After the slag flushing water exhausted steam 6 escapes upward from the heat exchange tube, it mixes with the cold air outside the heat exchange tube to form a dry mixed gas 10. At this time, the temperature of the dry mixed gas 10 can be reduced to about 52 degrees, and it is uniformly sucked and discharged into the outside atmosphere through the dry mixed gas induced draft fan 9.

[0096] Preferably, a temperature flow meter 11 is provided at the top of the heat exchange tube and below the dry mixed gas induced draft fan 9. The temperature flow meter 11 can monitor the air temperature and flow rate at the dry mixed gas induced draft fan 9 in real time. When the temperature there is too high, such as when the temperature is higher than 53 degrees, the spray assembly 7 is controlled to increase the spray volume, and the cold air blower 15 is controlled to increase the air intake volume. A regulating control module is also provided in the blast furnace slag flushing water and exhaust steam dewhitening treatment and water saving system. The regulating control module receives the flow rate and temperature information detected in real time by the temperature flow meter 11, and automatically controls the working conditions of the cyclone fan, spray assembly, dry mixed gas induced draft fan, and cold air blower in the blast furnace slag flushing water and exhaust steam dewhitening treatment and water saving system in combination with the current outdoor temperature and other external conditions, to ensure that the blast furnace slag flushing water and exhaust steam dewhitening treatment and water saving system is always in a reasonable working state.

[0097] The temperature flow rate meter can be selected from existing temperature flow rate meters in the art, as long as it can achieve the above functions, and this application does not make any special restrictions on this.

[0098] In a preferred embodiment, Figure 2 , Figure 3 As shown in , in the heat mass deoxidizer body 8, the heat exchange tubes 21 are divided into multiple groups, i.e., multiple tube bundle groups. Preferably, four tube bundle groups A, B, C, and D are installed in the frame 19 of the heat mass deoxidizer body 8. Each tube bundle group can be transported and installed separately. Multiple lining bone plates 18 and multiple fixing plates 20 are arranged around each tube bundle group. The lining bone plates 18 and the fixing plates 20 fix the tube bundle group as a whole, and ensure that the heat exchange tubes therein will not be relatively displaced.

[0099] Preferably, the lining bone plate 18 is vertically arranged, and its length extension direction is consistent with the extension direction of the heat exchange tube, and the fixing plate 20 is horizontally arranged and fixed on the lining bone plate 18, so as to further enhance the connection strength between each lining bone plate 18 and improve the overall strength of each tube bundle group;

[0100] Preferably, four tube sheets 22 are also provided, one tube sheet 22 is provided under each tube bundle group, and the multiple tube sheets 22 are tightly connected to each other to ensure that no slag flushing water and exhausted steam 6 pass through the connection gaps.

[0101] More preferably, the lining bone plate 18 adjacent to the frame 19 is arranged in the frame 19 and is fixed to the frame 19 as a whole, so as to further enhance the overall strength of the thermal mass de-bleaching device body 8 and ensure that its strength can meet the use requirements. Dividing the heat exchange tubes in the thermal mass de-bleaching device body 8 into 4 fixed tube bundle groups can not only facilitate on-site installation and simplify the installation process, but also improve construction efficiency without fixing the heat exchange tubes one by one at the construction site. It can also take into account the convenience of equipment transportation. If the thermal mass de-bleaching device body 8 is taken as a complete whole, it is difficult to transport it as a whole under the existing technical conditions due to its large volume and weight. Setting it into 4 tube bundle groups can perfectly solve the above problems.

[0102] In a preferred embodiment, Figure 4 As shown in , a spiral groove is provided on the inner wall of the heat exchange tube, and the depth of the spiral groove is about 2 mm. After the slag flushing water and exhausted steam 6 enter the heat exchange tube, it gradually rises in a spiral motion under the action of the spiral groove, thereby extending the heat exchange time between the spiral slag flushing water and exhausted steam 6 and the external cold air, and can also increase the heat transfer efficiency, thereby greatly improving the heat exchange capacity;

[0103] Further preferably, heat transfer fins are provided on the outside of the heat exchange tube, and the heat transfer fins are spiral, thereby increasing the contact area between the cold air entering the thermal mass deoxidizer body 8 and the heat exchange tube, thereby increasing the heat transfer efficiency.

[0104] In a preferred embodiment, the thermal mass deoxidizer body 8 comprises a shell which is sealed around and opened at both ends, and the heat exchange tube is placed and fixed in the shell;

[0105] The thermal mass deoxidizer base 5 comprises a shell which is sealed at the periphery and the lower end and opened at the upper end, and the cavity for storing the slag flushing water and the steam is located in the shell;

[0106] The lower end of the thermal mass deoxidizer body 8 is fixed to the upper end of the thermal mass deoxidizer base 5 to form a thermal mass deoxidizer. The hollow cavity inside the thermal mass deoxidizer is divided into upper and lower parts by the tube sheet 22.

[0107] A slag flushing water and exhausted steam inlet is provided on the side of the thermal mass dewhitening device base 5, and a slag flushing water and exhausted steam outlet pipe 3 is fixed to the side of the thermal mass dewhitening device base 5 through the side. A liquid collecting tank surrounded by the shell is provided at the bottom of the dewhitening device base 5, and an outlet pipe is provided on the shell at the bottom of the liquid collecting tank to lead the water in the liquid collecting tank to the water treatment equipment; a cold air inlet is provided on the side of the thermal mass dewhitening device body 8, and the cold air connecting pipe 12 is fixed to the side of the thermal mass dewhitening device body 8 through the cold air inlet;

[0108] The top of the thermal mass dewhitener body 8 is open, and the slag-washing water-exhausted steam and cold air are discharged from the top of the thermal mass dewhitener body 8. After the slag-washing water-exhausted steam escapes from the heat exchange tube, the slag-washing water-exhausted steam and the cold air are mixed to form a dry mixed gas, which are discharged from the top of the thermal mass dewhitener body 8 under the action of the dry mixed gas induced draft fan 9.

[0109] In a preferred embodiment, Figure 5 As shown in , the spray assembly includes a spray head 71 and a spray pipe 72, wherein there are multiple spray heads, each of which is connected to the spray pipe 72, and the cooling water to be sprayed is transported to the spray head 71 through the spray pipe 72;

[0110] The nozzles are arranged in two layers. The nozzles 71 located in the lower layer all spray cooling water downward, and the nozzles 71 located in the upper layer all spray cooling water sideways, so as to facilitate the condensed water and cooling water to be closer to the inner wall of the thermal mass deoxidizer base 5, so as to facilitate the formation of water droplets sliding from the side wall to the liquid collection tank; 12 nozzles are arranged in a circle on the upper layer to spray cooling water outward, and 41 nozzles are arranged in a circular array on the lower layer to spray cooling water downward.

[0111] The present invention also provides a method for descaling and water-saving of blast furnace slag flushing water deficient steam, the method comprising the following steps:

[0112] The slag flushing water-exhausted steam 6 in the slag ditch 1 is led out to the base 5 of the thermal mass desulphurizer through the slag flushing water-exhausted steam outlet pipe 3 by the cyclone fan 2; at this time, the temperature of the slag flushing water-exhausted steam 6 is about 95 degrees.

[0113] The slag flushing water-exhausted steam 6 is sprayed through the spray assembly 7, and the slag flushing water-exhausted steam 6 escapes upward through the spray assembly 7 and enters the heat exchange tube 21;

[0114] Cold air is injected into the thermal mass deoxidizer body 8 through the cold air connecting pipe 12, and the cold air moves upward outside the heat exchange tube, continuously exchanges heat with the slag-washing water-exhausted steam 6 inside the heat exchange tube, further cooling the slag-washing water-exhausted steam 6, causing the water vapor therein to condense and flow back to the thermal mass deoxidizer base 5 along the inner wall of the heat exchange tube, thereby reducing the temperature of the dry mixed gas 10 obtained at the dry mixed gas induced draft fan 9 to 50-55 degrees Celsius.

[0115] Example:

[0116] 1080m 3 The steel output of the effective volume blast furnace is 4,000 tons / day, the slag output is 1,600 tons / day, and the slag flushing water used for flushing steel slag is 1,246 tons per day; among them, about 250 tons of slag flushing water is directly discharged into the atmosphere through the chimney in the form of slag flushing water exhaust steam. The specific indicators obtained by monitoring the slag flushing water exhaust steam are as follows:

[0117] The average temperature of the slag-washing water steam when it is discharged from the chimney is 93 degrees Celsius, and the average concentration of particulate matter when it is discharged from the chimney is 40mg / Nm 3 , the average concentration of sulfur dioxide (SO2) is 160mg / Nm 3 、Nitrogen oxides (NO X )The average concentration is 300mg / Nm 3 On a clear day, obvious white smoke can be observed with the naked eye within 10 km of the chimney.

[0118] The blast furnace slag flushing water exhaust steam dewhitening treatment and water-saving system provided in the present application is installed near the slag ditch of the above-mentioned blast furnace, the thermal mass dewhitening device base is fixed on the ground near the slag ditch, and the slag flushing water exhaust steam lead-out pipe is installed above the slag ditch, and the slag flushing water exhaust steam is introduced into the thermal mass dewhitening device base through the slag flushing water exhaust steam lead-out pipe. A liquid collecting tank is arranged at the bottom of the thermal mass dewhitening device base, and a spray assembly is arranged at the top of the inner part; a thermal mass dewhitening device body connected to the thermal mass dewhitening device base is installed above the thermal mass dewhitening device base, and a tube sheet and a heat exchange tube are arranged in the thermal mass dewhitening device body, wherein there are 1600 heat exchange tubes in total, each of which has an inner diameter of 80 mm, a spiral groove is opened inside each heat exchange tube, and a heat transfer fin is arranged outside each heat exchange tube; a cold air connecting pipe is also arranged on the side of the thermal mass dewhitening device body to inject cold air into the gap outside the heat exchange tube;

[0119] The slag flushing water exhaust steam in the slag ditch is led out to the base of the thermal mass dewhitener through the slag flushing water exhaust steam outlet pipe by the cyclone fan. The temperature of the slag flushing water exhaust steam when entering the base of the thermal mass dewhitener is 95 degrees. The total amount of slag flushing water exhaust steam entering the base of the thermal mass dewhitener is 288,000 m3 per day. 3 (standard atmospheric pressure);

[0120] The daily water spray volume of the spray assembly is 192,000 m 3 After the slag flushing water exhaust steam is sprayed by the spraying component 7, the temperature of the slag flushing water exhaust steam is reduced to 85 degrees Celsius;

[0121] The slag flushing water exhaust steam passes through the spray assembly and enters the heat exchange tube. Cold air is injected into the thermal mass dewhitening device body through the cold air connecting pipe to cool the heat exchange tube and the slag flushing water exhaust steam. The daily injection volume of cold air is 6 million m 3 (standard atmospheric pressure); so that the final dry mixed gas is 52 degrees Celsius and discharged into the atmosphere.

[0122] 156 tons of condensed water can be recovered from the sump every day, that is, the difference between the water collected in the sump and the cooling water sprayed by the spray assembly is 156 tons.

[0123] The monitoring results of pollutant content in the slag flushing water exhausted steam discharged from the heat exchange tubes are as follows:

[0124] The average concentration of particulate matter is 10 mg / Nm 3 , the average concentration of sulfur dioxide (SO2) is 35mg / Nm 3 、Nitrogen oxides (NO X )The average concentration is 50mg / Nm 3 , and on a clear day, no obvious white smoke was seen within 10km of the chimney, and no obvious white smoke was seen within 1km of the chimney;

[0125] It can be seen from the above embodiments that after installing the blast furnace slag water exhaust steam dewhitening treatment and water-saving system provided in this application, water resources can be greatly saved. 156 tons can be recovered from about 250 tons of slag water that is directly discharged into the atmosphere through the chimney in the form of slag water exhaust steam, and the recovery rate is more than half, thereby eliminating the white smoke / white dragon phenomenon and reducing the emission of pollutants, so that the pollutant emissions are far lower than the emission standards prescribed by the state.

[0126] The present invention has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, the present invention may be subjected to a variety of substitutions and improvements, all of which fall within the scope of protection of the present invention.

Claims

1. A blast furnace slag flushing water deficient steam dewhitening treatment and water saving system, characterized in that: The system comprises a slag flushing water exhausted steam outlet pipe (3), one end of which is located above the slag ditch (1) and the other end of which is connected to the thermal mass descaling device base (5); The slag flushing water spent steam (6) in the slag ditch (1) enters the thermal mass descaling device base (5) through the slag flushing water spent steam outlet pipe (3); The base (5) of the thermal mass descaling device is provided with a cavity for accommodating slag flushing water and exhausted steam (6). A thermal mass deoxidizer body (8) connected to the cavity is arranged on the top of the thermal mass deoxidizer base (5). The slag flushing water exhausted steam (6) is cooled down in the process of moving upward in the thermal mass dewhitening device body (8), and the water vapor therein condenses into liquid and flows back into the thermal mass dewhitening device base (5); A heat exchange tube (21) is arranged inside the thermal mass dewhitener body (8), and the slag washing water exhaust steam (6) in the thermal mass dewhitener base (5) moves upward inside the heat exchange tube (21) to the top of the thermal mass dewhitener body (8), during which the water vapor condenses into liquid and flows back into the thermal mass dewhitener base (5) along the inner wall of the heat exchange tube (21); A tube sheet (22) is provided inside the thermal mass dewhitening device body (8) near the thermal mass dewhitening device base (5), and the heat exchange tube (21) is fixed by the tube sheet, and the slag flushing water exhaust steam (6) is blocked to prevent the slag flushing water exhaust steam (6) from escaping from the outside of the heat exchange tube (21) to the top of the thermal mass dewhitening device body (8); A cold air communication pipe (12) is provided on the side of the lower end of the thermal mass descaling device body (8), and cold air is injected into the thermal mass descaling device body (8) through the cold air communication pipe (12). The cold air moves upward along the outside of the heat exchange tube (21) to absorb the heat carried by the slag flushing water exhaust steam (6) in the heat exchange tube; A dry mixed gas induced draft fan (9) is arranged on the top of the thermal mass descaling device body (8), and the dry mixed gas induced draft fan (9) is used to suck the slag flushing water spent steam (6) inside the heat exchange tube (21) and the cold air outside the heat exchange tube (21); A spray assembly (7) is also provided in the thermal mass deoxidizer base (5), and a temperature flow meter (11) is provided at the top of the heat exchange tube and below the dry mixed air induced draft fan (9). The temperature flow meter (11) can monitor the air temperature and flow rate at the dry mixed air induced draft fan (9) in real time. When the temperature at the location is higher than 53 degrees, the spray assembly (7) is controlled to increase the spray volume, and the cold air supply fan (15) is controlled to increase the air intake volume.

2. The blast furnace slag flushing water exhaust steam dewhitening treatment and water saving system according to claim 1 is characterized in that: The spray assembly (7) is used to spray cooling water into the cavity in the thermal mass descaling device base (5) to cool the slag flushing water and exhausted steam (6) therein.

3. The blast furnace slag flushing water exhaust steam dewhitening treatment and water saving system according to claim 1, characterized in that: A cyclone fan (2) is provided on the slag flushing water spent steam outlet pipe (3) for continuously leading the slag flushing water spent steam (6) from the slag ditch (1) to the thermal mass descaling device base (5); A pressure flow meter (4) is also provided on the slag flushing water exhausted steam outlet pipe (3) for monitoring and recording the amount of slag flushing water exhausted steam (6) introduced.

4. The blast furnace slag flushing water exhaust steam dewhitening treatment and water saving system according to claim 2, characterized in that: The system also includes a spray pump (17) disposed on the ground, wherein the spray pump (17) is connected to the spray assembly (7) via a spray pipeline (16) to provide cooling water for the spray assembly (7).

5. The blast furnace slag flushing water exhaust steam dewhitening treatment and water saving system according to claim 1, characterized in that: The system further comprises a cold air blower (15) arranged on the ground, wherein the cold air blower (15) is connected to the cold air connecting pipe (12) via a cold air pipe (14) to provide cold air for the cold air connecting pipe (12); The system also includes a cold air duct support (13) for supporting the cold air duct (14).

6. A method for descaling and saving water from steam used to flush slag from a blast furnace, characterized in that: In the method, the system as claimed in any one of claims 1 to 5 is used to remove the whiteness and save water of the exhausted steam of blast furnace slag flushing water.

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