Waste steel recovery equipment and treatment method

Abstract

The invention discloses waste steel recovery equipment and a treatment method, the waste steel recovery equipment comprises a crusher, a conveyor belt, a separation tank and a condensation separation box, a pair of crushing rollers is rotatably connected in the crusher, and the pair of crushing rollers crush waste steel to form iron sheets when rotating; the conveying belt is mounted at the lower parts of the pair of crushing rollers and is used for conveying iron sheets; a heating rod is mounted in the separation tank, the heating rod is connected with municipal electricity, the iron sheet enters the separation tank after passing through the conveying belt, and the heating rod heats the iron sheet in the separation tank to 600-800 DEG C so as to analyze paint on the iron sheet. The method has the beneficial effects that the problems that a traditional mechanical paint removal method is high in labor intensity, low in efficiency, prone to damage a base body and prone to dust pollution are solved, and meanwhile the problems of equipment corrosion, high potential safety hazards, VOCs emission and secondary pollution caused by the fact that a chemical paint removal method uses a highly-corrosive agent can be solved.

Description

Technical Field

[0001] This invention relates to the technical field, specifically to a waste steel recycling equipment and processing method. Background Technology

[0002] With the development of the renewable resource recycling industry, the amount of scrap steel being recycled continues to increase. It is very common for scrap steel materials to have paint or anti-corrosion coatings on their surfaces, such as scrapped car body panels, discarded paint buckets, coated scrap steel plates, and scrap steel structures. These scrap steel materials need to have their paint removed before being reused to ensure the quality of the steel.

[0003] Traditional paint stripping methods mainly include mechanical peeling and chemical etching. Mechanical stripping requires workers to repeatedly apply force using tools such as grinders and scrapers to remove the paint, resulting in high labor intensity, low efficiency, and inability to meet the needs of large-scale processing. Furthermore, the instability of mechanical forces can easily damage the steel substrate, reducing the quality of the recycled material, and generating large amounts of dust during processing, polluting the working environment and increasing subsequent remediation costs.

[0004] Chemical paint stripping relies on highly corrosive agents to peel off the paint. While this method is fast, the corrosive agents can erode the steel substrate, leading to high investment and maintenance costs for corrosion protection equipment. Furthermore, many chemical paint strippers contain organic solvents, which are not only flammable and explosive but can also cause excessive VOC emissions, posing a serious threat to the environment and operational safety, and potentially causing secondary pollution of soil and water bodies.

[0005] Therefore, in order to address the above-mentioned technical problems, it is necessary to provide a waste steel recycling equipment and processing method. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a waste steel recycling equipment and processing method to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a waste steel recycling device, including a crusher, a conveyor belt, a separation tank, and a condensation separation box. A pair of crushing rollers are rotatably connected inside the crusher, crushing the waste steel into iron sheets as they rotate. The conveyor belt is installed below the crushing rollers and transports the iron sheets. A heating rod is installed inside the separation tank and connected to municipal power. After passing through the conveyor belt, the iron sheets enter the separation tank, where the heating rod heats them to 600-800°C to remove paint from the sheets. A fourth pipe and a fifth pipe are fixedly connected to the condensation separation box. The end of the fourth pipe away from the condensation separation box is fixedly connected to the separation tank, and the end of the fifth pipe away from the condensation separation box is fixedly connected to a gas collecting tank.

[0008] In one or more embodiments of the present invention, the crusher is equipped with a plurality of water spray heads, all of which are located below a pair of crushing rollers. When the crushing rollers crush scrap steel, the plurality of water spray heads spray cleaning fluid to clean the iron sheet. The scrap steel recycling equipment also includes a water storage tank located below the crusher, and the cleaning fluid sprayed from the water spray heads flows into the water storage tank.

[0009] In one or more embodiments of the present invention, a drying mechanism is further included, the drying mechanism comprising a first hopper and an air pump, the first hopper being located at the end of the conveyor belt away from the crusher, an inclined perforated plate being fixedly connected inside the first hopper, and a plurality of air jets being installed on the perforated plate; a second pipe is fixedly connected to the air pump, the end of the second pipe away from the air pump extending into the first hopper, and a third pipe being fixedly connected to the end of the second pipe extending into the first hopper, the air jets being fixedly connected to the third pipe.

[0010] In one or more embodiments of the present invention, an auger is fixedly installed on the first hopper, and a heating box is fixedly connected to the outlet end of the auger. A heat insulation plate is fixedly connected inside the heating box, and the heat insulation plate divides the space inside the heating box into a preheating chamber and a heating chamber. A separation tank is fixedly installed inside the heating chamber. A second hopper is fixedly installed inside the preheating chamber. A seventh tube is integrally formed on the second hopper. The end of the seventh tube away from the heating box is connected to the separation tank. A solenoid valve is fixedly installed on the seventh tube.

[0011] In one or more embodiments of the present invention, a plurality of ignition guns are fixedly installed inside the heating chamber, and a sixth tube connected to the heating chamber is fixedly connected to the gas collecting tank.

[0012] In one or more embodiments of the present invention, an air valve is fixedly installed on the heat insulation plate.

[0013] In one or more embodiments of the present invention, a first pipe body connected to the preheating chamber is fixedly connected to the air pump.

[0014] In one or more embodiments of the present invention, the condensation separation box is provided with a shell-and-tube condenser.

[0015] A method for recycling and processing scrap steel includes the following steps: S1, pre-crushing treatment: The scrap steel to be processed is fed into the crusher, and a pair of opposing rotating crushing rollers inside the crusher are started. Through the shearing and squeezing action of the crushing rollers, the scrap steel is crushed into iron pieces of a preset size, breaking the continuity of the paint layer on the surface of the steel and increasing the contact area for subsequent heat exchange of the steel. S2, Closed-loop thermal desorption paint removal: The iron sheet obtained in step S1 is conveyed to a closed separation tank via a conveyor belt. The heating rod inside the separation tank is activated to raise the temperature inside the separation tank to 600-800℃. The iron sheet is heated at a constant temperature, causing the organic polymer of the paint adhering to the surface of the iron sheet to undergo a thermal decomposition reaction, decomposing into gaseous hydrocarbons and tar vapor, thus achieving complete separation of the paint coating from the steel substrate. The entire process is closed to prevent dust from escaping. S3, Oil-Gas Condensation Separation: The high-temperature oil-gas mixture generated in the separation tank is introduced into the condensation separation box through the fourth pipe. After being cooled by the tubular condenser inside the condensation separation box, the high-boiling-point tar liquid component is separated and collected and stored. The low-boiling-point non-condensable combustible gas is transported to the gas collection tank through the fifth pipe for temporary storage and backup, thus completing the classification and recovery of paint cracking products.

[0016] In one or more embodiments of the present invention, a water spray head is provided below the crushing roller inside the crusher. The water spray head is activated simultaneously with the crushing operation to spray clean water or cleaning liquid containing surfactants to spray the crushed iron pieces, suppress dust flying and wash away soluble impurities on the surface of the iron pieces. The cleaning waste liquid is collected in the water storage tank through the bottom collection hopper of the crusher, and recycled after sedimentation and filtration. The pre-cleaned iron sheet is conveyed to the first hopper via a conveyor belt. The iron sheet slides down the inclined perforated plate inside the first hopper. The air pump is started to generate a high-speed airflow, which is conveyed through the second and third pipes to the jet nozzle and sprayed out. The high-speed airflow sweeps away the moisture on the surface of the iron sheet, completing the drying process and reducing the energy consumption of subsequent thermal desorption. After drying, the iron sheets are quantitatively conveyed by an auger to the second hopper in the preheating chamber of the heating box for temporary storage. By controlling the intermittent opening of the solenoid valve on the seventh tube, the iron sheets are intermittently fed into the separation tank, connecting the upstream continuous crushing and drying process with the downstream batch thermal desorption process, thus realizing continuous production throughout the entire process. The non-condensable combustible gas temporarily stored in the gas collecting tank is transported to the heating chamber of the heating box through the sixth pipe. It is ignited by an ignition gun to provide the main heat source for the separation tank and reduce the mains power consumption of the heating rod. The waste heat of the high-temperature flue gas in the heating chamber is introduced into the preheating chamber through the gas valve on the heat insulation plate to preheat the iron sheet to be treated. The waste heat gas after heat exchange is extracted by the air pump through the first pipe and used for jet head purging and drying, realizing the cascade recycling of thermal energy.

[0017] The beneficial effects of this invention are that it solves the problems of high labor intensity, low efficiency, easy damage to the substrate, and dust pollution caused by traditional mechanical paint stripping methods, while avoiding the problems of equipment corrosion, high safety hazards, VOC emissions, and secondary pollution caused by the use of highly corrosive agents in chemical paint stripping methods. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a scrap steel recycling device according to one embodiment of the present invention; Figure 2 This is a cross-sectional view of a crusher in a scrap steel recycling equipment according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of the drying mechanism of a scrap steel recycling device according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the heating box of a scrap steel recycling device according to an embodiment of the present invention; Figure 5 This is a cross-sectional view of the separation tank of a scrap steel recycling device according to an embodiment of the present invention; Figure 6 The present invention provides a flowchart of a method for recycling and processing scrap steel in one embodiment. Figure 1 ; Figure 7 The present invention provides a flowchart of a method for recycling and processing scrap steel in one embodiment. Figure 2 ; Figure 8 The present invention provides a flowchart of a method for recycling and processing scrap steel in one embodiment. Figure 3 .

[0020] Explanation of reference numerals in the attached figures: 1. Crusher; 11. Crushing roller; 12. Water spray head; 13. Water storage tank; 2. Conveyor belt; 3. First hopper; 31. Mesh plate; 311. Air jet head; 32. Screw conveyor; 4. Air pump; 41. First pipe body; 42. Second pipe body; 43. Third pipe body; 5. Condensation separation box; 51. Fourth pipe body; 52. Fifth pipe body; 6. Gas collection tank; 61. Sixth pipe body; 7. Heating box; 701. Preheating chamber; 702. Heating chamber; 71. Insulation plate; 711. Air valve; 72. Second hopper; 721. Seventh pipe body; 73. Solenoid valve; 74. Ignition gun; 8. Separation tank; 81. Heating rod. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: like Figures 1 to 5 As shown, a waste steel recycling device according to one embodiment of the present invention includes a crusher 1, a conveyor belt 2, a separation tank 8, and a condensation separation box 5. The crusher 1 serves as a pretreatment unit, and a pair of crushing rollers 11 are rotatably connected inside it. During operation, the pair of crushing rollers 11 rotate in opposite directions under the drive of the drive device, applying shearing and squeezing action to the incoming waste steel, such as scrapped car skins and waste paint buckets, crushing them into iron pieces of a certain size to increase the contact area between the steel and the subsequent heat carrier and improve heat transfer efficiency; on the other hand, disrupting the continuity of the paint layer helps the pyrolysis gases escape.

[0023] The conveyor belt 2 is installed below a pair of crushing rollers 11 to receive and transport the crushed iron pieces to the next processing unit.

[0024] The separation tank 8 is the core processing unit of this equipment, and it is equipped with a heating rod 81, which is connected to the municipal power supply. The iron sheet is conveyed into the separation tank 8 via the conveyor belt 2. The heating rod 81 is activated, heating the iron sheet in the separation tank 8 to 600-800℃. Under this high-temperature environment, the paint adhering to the surface of the iron sheet undergoes complex physicochemical changes, namely a thermal decomposition reaction. The organic polymer molecules in the paint absorb energy at high temperatures, their molecular chains break, and they decompose into small-molecule gaseous hydrocarbons, tar vapor, and a small amount of solid carbon black. This process achieves the desorption and removal of the paint coating from the steel substrate. Because the thermal desorption process takes place within the sealed separation tank 8, the problem of dust spillage caused by mechanical paint removal is effectively avoided.

[0025] A fourth tube 51 and a fifth tube 52 are fixedly connected to the condenser-separator 5. The end of the fourth tube 51 furthest from the condenser-separator 5 is fixedly connected to the separator 8, used to exhaust the high-temperature oil-gas mixture containing paint cracking products generated in the separator 8. The end of the fifth tube 52 furthest from the condenser-separator 5 is fixedly connected to the gas collecting tank 6. After the high-temperature oil-gas mixture enters the condenser-separator 5, its temperature decreases after passing through the internal tubular condenser. The tar component with a higher boiling point condenses into a liquid and is collected and stored, while the non-condensable combustible gas with a lower boiling point, such as gases whose main components are hydrogen, methane, carbon monoxide, and other light hydrocarbons, enters the gas collecting tank 6 through the fifth tube 52 for temporary storage, to be used later.

[0026] This embodiment achieves efficient removal of paint from scrap steel and partial recovery of products through three core steps: crushing, thermal desorption, and condensation separation, thus overcoming the main drawbacks of traditional mechanical and chemical methods.

[0027] Example 2: Based on Example 1, this example further optimizes the pretreatment process and adds a continuous production function module, aiming to solve problems such as dust pollution, excessive moisture content of iron sheets, and discontinuous production during the crushing process.

[0028] like Figure 1 and Figure 2 As shown, to address the dust problem during the crushing process, multiple water spray heads 12 are installed inside the crusher 1. These spray heads 12 are all located below a pair of crushing rollers 11. When the crushing rollers 11 crush scrap steel, the spray heads 12 spray water or a cleaning solution containing surfactants to wash the freshly crushed iron sheets. This not only suppresses the emission of fine dust that may be generated during the crushing process, improving the working environment, but also dissolves or washes away some soluble contaminants and loose impurities adhering to the surface of the iron sheets, thus achieving a preliminary purification effect.

[0029] Furthermore, such as Figures 1 to 5 As shown, the scrap steel recycling equipment also includes a water storage tank 13, which is located below the crusher 1. The cleaning fluid sprayed from the water nozzles 12 rinses the iron sheets and then flows into the water storage tank 13 through the collection hopper at the bottom of the crusher 1. The liquid in the water storage tank 13 can be recycled after sedimentation and filtration, thus saving water resources.

[0030] After being sprayed and cleaned, the iron sheets have moisture adhering to their surface. If they were to directly enter the high-temperature separation tank 8, the rapid vaporization of this moisture would consume a large amount of heat energy, increasing energy consumption. Therefore, this embodiment includes a drying mechanism.

[0031] Specifically, the drying mechanism includes a first hopper 3 and an air pump 4. The first hopper 3 is located at the end of the conveyor belt 2 away from the crusher 1 and is used to catch iron sheets falling from the conveyor belt 2. An inclined perforated plate 31 is fixedly connected inside the first hopper 3, and multiple air jets 311 are installed on the perforated plate 31. A second pipe 42 is fixedly connected to the air pump 4. The end of the second pipe 42 away from the air pump 4 extends into the first hopper 3, and the end of the second pipe 42 extending into the first hopper 3 is fixedly connected to a third pipe 43. The air jets 311 are fixedly connected to the third pipe 43. When the air pump 4 is working, it generates a high-speed airflow, which is conveyed through the second pipe 42 and the third pipe 43, and finally ejected at high speed from the air jets 311. As the iron sheets slide down the inclined perforated plate 31 under gravity, they are blown by the high-speed airflow, and the moisture attached to their surface is evaporated at an accelerated rate, thereby achieving the purpose of drying.

[0032] To achieve continuous production, this embodiment adds a buffer and intermittent feeding structure after the drying unit. Specifically, an auger 32 is fixedly installed on the first hopper 3. The inlet of the auger 32 is connected to the bottom outlet of the first hopper 3, and a heating chamber 7 is fixedly connected to its outlet end. A heat insulation plate 71 is fixedly connected inside the heating chamber 7, dividing the internal space of the heating chamber 7 into a preheating chamber 701 and a heating chamber 702. A separation tank 8 is fixedly installed inside the heating chamber 702. As the iron sheet falls from the conveyor belt 2 onto the perforated plate 31 and slides from the perforated plate 31 onto the auger 32, a dryer nozzle 311 sprays dry gas to dry the iron sheet. The dried iron sheet is then quantitatively and controllably conveyed by the auger 32 to the second hopper 72 inside the heating chamber 7. The second hopper 72 is fixedly installed inside the preheating chamber 701. A seventh tube 721 is integrally formed on the second hopper 72. The end of the seventh tube 721 furthest from the heating chamber 7 is connected to the separation tank 8. A solenoid valve 73 is fixedly installed on the seventh tube 721. The dried iron sheets first enter the second hopper 72 for temporary storage. When the separation tank 8 completes a batch processing and needs to be fed, the solenoid valve 73 is opened, and the iron sheets enter the separation tank 8 by gravity through the seventh tube 721. When the separation tank 8 is heating and desorbing the paint on the iron sheets, the solenoid valve 73 is closed, and the crushed and dried iron sheets are temporarily stored in the second hopper 72. Through the buffer hopper and intermittent feeding, an effective connection is achieved between the continuous operation of the upstream crushing and drying processes and the batch operation of the downstream thermal desorption processes, thus realizing continuous production of the entire system.

[0033] Based on Example 1, this embodiment introduces a spray dust suppression, airflow drying, and buffer feeding module, which not only improves the working environment and reduces the energy consumption of the thermal desorption process, but more importantly, enables continuous operation of the equipment and significantly improves processing efficiency.

[0034] Example 3: Based on Example 2, this example further integrates an energy recycling system, which aims to use the non-condensable combustible gas generated by thermal desorption as the system heat source and to utilize the waste heat of flue gas in a cascade manner, thereby achieving energy self-sufficiency in the process and significantly reducing operating costs.

[0035] like Figures 1 to 5 As shown, to achieve energy self-sufficiency, multiple ignition guns 74 are fixedly installed inside the heating chamber 702. A sixth pipe 61, connected to the heating chamber 702, is fixedly connected to the gas collecting tank 6. The paint on the iron sheet inside the separator 8 decomposes at high temperature, and the resulting high-temperature oil and gas enters the condensation recovery unit inside the condensation separation box 5 via the fourth pipe 51. In the condensation separation box 5, the high-temperature oil and gas is cooled, and the high-boiling-point fuel oil components are condensed and separated, stored in an oil storage tank, and can be sold as industrial fuel, achieving resource utilization. The separated non-condensable combustible gas is purified through processes such as acid removal and coking removal, and then transported through pipelines to the gas collecting tank 6 for temporary storage to stabilize the gas source pressure and flow rate. When needed, the combustible gas in the gas collecting tank 6 is input into the heating chamber 702 through the sixth pipe 61. Under the high-energy ignition of the ignition gun 74, the combustible gas mixes with combustion air and burns. The heat generated by combustion directly heats the separator 8. This approach fully utilizes the heat energy derived from the paint waste carried by the scrap steel, significantly reducing the power consumption of the heating rod 81. When the calorific value of the pyrolysis gas is insufficient or the system is started, the heating rod 81 or external fuel can be used to ensure stable process temperature. This energy cycle mode is key to achieving economical and environmentally friendly operation of this equipment.

[0036] To further recover and utilize the waste heat from the flue gas and improve overall thermal efficiency, a gas valve 711 is fixedly installed on the heat insulation plate 71. The high-temperature flue gas generated by combustion in the heating chamber 702, after heating the separator 8, still carries a large amount of waste heat. By opening the gas valve 711, this high-temperature gas can pass through the heat insulation plate 71 and enter the preheating chamber 701 from the heating chamber 702. The high-temperature flue gas exchanges heat with the outer wall and bottom of the second hopper 72 in the preheating chamber 701, thereby preheating the iron sheets to be analyzed in the second hopper 72. The temperature of the iron sheets is increased before entering the separator 8, shortening their heating time in the separator 8 and further reducing the energy consumption of the main heating process. The low-temperature flue gas after heat exchange can finally be discharged through the chimney.

[0037] To further enhance the drying effect of the drying mechanism and realize the recycling of hot air in the preheating chamber 701, a first pipe 41 connected to the preheating chamber 701 is fixedly connected to the suction pump 4. Inside the preheating chamber 701, after heat exchange, the temperature of the high-temperature flue gas decreases, but it still contains a certain amount of heat and is relatively dry. The suction pump 4 extracts this portion of hot gas from the preheating chamber 701 through the first pipe 41 and then discharges it into the jet head 311 through the second pipe 42. Using the preheated hot gas to purge the freshly broken wet iron sheets, compared to room temperature air, results in a higher saturated moisture content and stronger moisture-carrying capacity, thus significantly enhancing the drying effect and achieving cascaded energy utilization.

[0038] This embodiment, building upon the continuous production achieved in Embodiment 2, utilizes an energy recycling network to convert combustible waste generated during the thermal desorption process into thermal energy, maximizing its utilization. This means that, except during the start-up phase, the equipment requires virtually no external energy supplementation when processing scrap steel, resulting in extremely low operating costs and significant environmental and economic benefits.

[0039] like Figures 1 to 8 As shown, a method for recycling and processing scrap steel includes the following steps: S1, pre-treatment of crushing: The scrap steel to be processed is fed into the crusher 1, and a pair of opposing rotating crushing rollers 11 inside the crusher 1 are started. Through the shearing and squeezing action of the crushing rollers 11, the scrap steel is crushed into iron pieces of a preset size, breaking the continuity of the paint layer on the surface of the steel, and increasing the contact area for subsequent heat exchange of the steel. S2, Closed-loop thermal desorption paint removal: The iron sheet obtained in step S1 is conveyed to the closed separation tank 8 via conveyor belt 2. The heating rod 81 inside the separation tank 8 is activated to raise the temperature inside the separation tank 8 to 600-800℃, and the iron sheet is heated at a constant temperature. This causes the organic polymer of the paint attached to the surface of the iron sheet to undergo a thermal decomposition reaction, decomposing into gaseous hydrocarbons and tar vapor, thus achieving complete separation of the paint coating from the steel substrate. The entire process is closed to prevent dust from escaping. S3, Oil-gas condensation and separation: The high-temperature oil-gas mixture generated in the separator 8 is introduced into the condensation separator 5 through the fourth pipe 51. After being cooled by the tubular condenser inside the condensation separator 5, the high-boiling-point tar liquid component is separated and collected and stored. The low-boiling-point non-condensable combustible gas is transported to the gas collection tank 6 through the fifth pipe 52 for temporary storage and backup, thus completing the classification and recovery of paint cracking products.

[0040] Specifically, a water spray head 12 is installed below the crushing roller 11 inside the crusher 1. The water spray head 12 is activated simultaneously with the crushing operation to spray clean water or cleaning liquid containing surfactants to spray the crushed iron pieces, suppress dust flying and wash away soluble impurities on the surface of the iron pieces. The cleaning waste liquid is collected in the water storage tank 13 through the bottom collection hopper of the crusher 1, and recycled after sedimentation and filtration.

[0041] The pre-cleaned iron sheet is conveyed to the first hopper 3 via conveyor belt 2. The iron sheet slides down the inclined perforated plate 31 inside the first hopper 3. The vacuum pump 4 is started to generate a high-speed airflow, which is conveyed to the jet nozzle 311 through the second pipe 42 and the third pipe 43 and sprayed out. The high-speed airflow sweeps away the moisture on the surface of the iron sheet, completing the drying process and reducing the energy consumption of subsequent thermal desorption.

[0042] After drying, the iron sheets are quantitatively conveyed by the screw conveyor 32 to the second hopper 72 in the preheating chamber 701 of the heating box 7 for temporary storage. By controlling the intermittent opening of the solenoid valve 73 on the seventh tube 721, the iron sheets are intermittently fed into the separation tank 8, connecting the upstream continuous crushing and drying process with the downstream batch thermal desorption process, and realizing continuous production throughout the entire process.

[0043] The non-condensable combustible gas temporarily stored in the gas collecting tank 6 is transported to the heating chamber 702 of the heating box 7 through the sixth pipe 61. It is ignited by the ignition gun 74 to provide the main heat source for the separation tank 8 and reduce the mains power consumption of the heating rod 81. The waste heat of the high-temperature flue gas in the heating chamber 702 is introduced into the preheating chamber 701 through the gas valve 711 on the heat insulation plate 71 to preheat the iron sheet to be processed. The waste heat gas after heat exchange is extracted by the air pump 4 through the first pipe 41 and used for purging and drying by the jet head 311 to realize the cascade recycling of thermal energy.

[0044] Obviously, the above-described embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A scrap steel recycling device, characterized in that, include: The crusher (1) has a pair of crushing rollers (11) rotatably connected inside it. When the pair of crushing rollers (11) rotate, they crush scrap steel into iron sheets. Conveyor belt (2), which is installed under a pair of crushing rollers (11) for transporting iron sheets; Separation tank (8), a heating rod (81) is installed inside the separation tank (8), the heating rod (81) is connected to municipal power, the iron sheet enters the separation tank (8) after passing through the conveyor belt (2), the heating rod (81) heats the iron sheet in the separation tank (8) to 600-800℃, so as to decompose the paint on the iron sheet; A condensation separator (5) is fixedly connected to a fourth pipe (51) and a fifth pipe (52). The end of the fourth pipe (51) away from the condensation separator (5) is fixedly connected to a separator (8), and the end of the fifth pipe (52) away from the condensation separator (5) is fixedly connected to a gas collecting tank (6).

2. The scrap steel recycling equipment as described in claim 1, characterized in that, The crusher (1) is equipped with multiple water spray heads (12), which are located below a pair of crushing rollers (11). When the crushing rollers (11) crush scrap steel, the multiple water spray heads (12) spray out cleaning fluid to clean the iron sheet. The scrap steel recycling equipment also includes a water storage tank (13), which is located below the crusher (1). The cleaning fluid sprayed by the water spray heads (12) flows into the water storage tank (13).

3. The scrap steel recycling equipment as described in claim 2, characterized in that, It also includes a drying mechanism, which includes a first hopper (3) and a vacuum pump (4). The first hopper (3) is located at one end of the conveyor belt (2) away from the crusher (1). An inclined mesh plate (31) is fixedly connected inside the first hopper (3). Multiple air jets (311) are installed on the mesh plate (31). A second pipe (42) is fixedly connected to the air pump (4). The end of the second pipe (42) away from the air pump (4) extends into the first hopper (3). The end of the second pipe (42) extending into the first hopper (3) is fixedly connected to a third pipe (43). The jet head (311) is fixedly connected to the third pipe (43).

4. The scrap steel recycling equipment as described in claim 3, characterized in that, A screw conveyor (32) is fixedly installed on the first hopper (3). A heating box (7) is fixedly connected to the outlet end of the screw conveyor (32). A heat insulation plate (71) is fixedly connected inside the heating box (7). The heat insulation plate (71) divides the space inside the heating box (7) into a preheating chamber (701) and a heating chamber (702). The separation tank (8) is fixedly installed inside the heating chamber (702). The preheating chamber (701) is fixedly installed with a second hopper (72), and a seventh tube (721) is integrally formed on the second hopper (72). The end of the seventh tube (721) away from the heating box (7) is connected to the separation tank (8). A solenoid valve (73) is fixedly installed on the seventh tube (721).

5. The scrap steel recycling equipment as described in claim 4, characterized in that, Multiple ignition guns (74) are fixedly installed inside the heating chamber (702), and a sixth tube (61) connected to the heating chamber (702) is fixedly connected to the gas collecting tank (6).

6. The scrap steel recycling equipment as described in claim 5, characterized in that, An air valve (711) is fixedly installed on the heat insulation plate (71).

7. The scrap steel recycling equipment as described in claim 6, characterized in that, The air pump (4) is fixedly connected to a first pipe (41) that communicates with the preheating chamber (701).

8. The scrap steel recycling equipment as described in claim 1, characterized in that, The condensation separator (5) is equipped with a tubular condenser.

9. A method for recycling and processing scrap steel, characterized in that, Includes the following steps: S1, pre-treatment of crushing: The scrap steel to be processed is fed into the crusher (1), and a pair of opposing crushing rollers (11) inside the crusher (1) are started. Through the shearing and squeezing action of the crushing rollers (11), the scrap steel is crushed into iron pieces of a preset size, breaking the continuity of the paint layer on the surface of the steel and increasing the contact area for subsequent heat exchange of the steel. S2, Closed thermal desorption paint removal: The iron sheet obtained in step S1 is conveyed to the closed separation tank (8) via conveyor belt (2). The heating rod (81) inside the separation tank (8) is activated to raise the temperature inside the separation tank (8) to 600-800℃. The iron sheet is heated at a constant temperature, so that the organic polymer of the paint attached to the surface of the iron sheet undergoes thermal decomposition reaction, decomposing into gaseous hydrocarbons and tar vapor, thus achieving complete separation of the paint coating from the steel substrate. The entire process is closed to prevent dust from overflowing. S3, oil and gas condensation separation: The high-temperature oil and gas mixture generated in the separator (8) is introduced into the condensation separator (5) through the fourth pipe (51). After being cooled by the tubular condenser inside the condensation separator (5), the high-boiling-point tar liquid component is separated and collected and stored. The low-boiling-point non-condensable combustible gas is transported to the gas collection tank (6) through the fifth pipe (52) for temporary storage and backup, thus completing the classification and recovery of paint cracking products.

10. The method for recycling and processing scrap steel as described in claim 9, characterized in that, A water spray head (12) is installed below the crushing roller (11) inside the crusher (1). The water spray head (12) is started simultaneously during the crushing operation to spray clean water or cleaning liquid containing surfactants to spray the crushed iron pieces, suppress dust flying and wash away soluble impurities on the surface of the iron pieces. The cleaning waste liquid is collected in the water storage tank (13) through the bottom collection hopper of the crusher (1), and recycled after sedimentation and filtration. The pre-cleaned iron sheet is conveyed to the first hopper (3) via conveyor belt (2). The iron sheet slides down along the inclined mesh plate (31) inside the first hopper (3). The vacuum pump (4) is started to generate a high-speed airflow, which is conveyed to the jet nozzle (311) through the second pipe (42) and the third pipe (43) and sprayed out. The high-speed airflow sweeps away the moisture on the surface of the iron sheet, completing the drying process and reducing the energy consumption of subsequent thermal desorption. After drying, the iron sheets are quantitatively transported by auger (32) to the second hopper (72) in the preheating chamber (701) of the heating box (7) for temporary storage. By controlling the intermittent opening of the solenoid valve (73) on the seventh tube (721), the iron sheets are intermittently fed into the separation tank (8), connecting the upstream continuous crushing and drying process with the downstream batch thermal desorption process, and realizing continuous production throughout the entire process. The non-condensable combustible gas temporarily stored in the gas collection tank (6) is transported to the heating chamber (702) of the heating box (7) through the sixth pipe (61), and ignited by the ignition gun (74) to provide the main heat source for the separation tank (8) and reduce the mains power consumption of the heating rod (81). The waste heat of the high temperature flue gas in the heating chamber (702) is introduced into the preheating chamber (701) through the gas valve (711) on the heat insulation plate (71) to preheat the iron sheet to be treated. The waste heat gas after heat exchange is extracted by the air pump (4) through the first pipe (41) and used for purging and drying by the jet head (311) to realize the cascade recycling of thermal energy.

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