Carbon basket and method for removing benzene series in coking initial rainwater by using same

Abstract

The invention relates to a carbon basket and a method for removing benzene series in coking initial rainwater by using the carbon basket. The initial coking rainwater sequentially flows through the coarse and fine grids and the plurality of carbon baskets, the coarse and fine grids are utilized to physically intercept large floating objects and benzene series in water, and the carbon baskets are utilized to physically intercept and adsorb the benzene series in the water. After the water is adsorbed by the carbon basket, the content of benzene series in the water is greatly reduced, and then the water sequentially enters a sand basin, a coagulative precipitation tank, a V-shaped filter tank, a chlorine disinfection tank, a clean water tank and the like of a traditional water treatment device to be treated and finally reaches the standard to be discharged or recycled. The benzene series adsorbed on the carbon basket is heated and converted into waste gas through heating, and the waste gas is discharged after reaching the standard after being adsorbed by the activated carbon bed. The activated carbon bed is regenerated through spraying, and spraying wastewater is fed into a coking phenol-cyanogen wastewater treatment system for deep oxidation, so that up-to-standard discharge of the wastewater is realized. The method has the advantages of simplicity in operation, low cost, good effect and the like, and can be used for effectively treating the initial coking rainwater and realizing up-to-standard discharge.

Description

Technical Field

[0001] This invention relates to the fields of iron and steel smelting and water treatment technology, specifically to a carbon basket and a method for removing benzene compounds from rainwater during the initial stage of coking. Background Technology

[0002] Benzene compounds are a byproduct of coal production and a harmful pollutant, with some (such as benzo(a)pyrene, anthracene, and naphthalene) exhibiting strong carcinogenicity. Under normal circumstances, during the high-temperature carbonization and coking process, benzene compounds in coal are released through the coke oven gas system and subsequently captured and utilized in the coking process. However, during coal charging, coke pushing, and venting from the top of the coke oven, some benzene compounds escape and disperse into the coking area, ultimately polluting the coking soil and causing surface pollution. During rainy weather, these benzene compounds enter the drainage system with rainwater, further polluting the aquatic environment. To prevent benzene pollution in coking wastewater, GB 16171-2012, "Emission Standard of Pollutants from Coking Chemical Industry," specifies that the concentration of benzene in directly discharged coking wastewater should be below 0.2 mg / L, and the concentration of benzo(a)pyrene should be below 0.03 μg / L. Because the emission concentration limits for benzene series compounds are relatively low, the initial rainwater, after simple treatment such as coagulation, sand filtration, and disinfection, is unlikely to meet the above emission standards.

[0003] To address this challenge, some companies have adopted technologies such as molecular sieve adsorption, biological treatment, and air flotation in the upstream water treatment stage. However, these methods still have some problems and shortcomings, specifically: (1) The initial rainfall is large, and the use of technologies such as molecular sieve adsorption, biological treatment and air flotation treatment has problems such as large land area and high investment.

[0004] (2) The molecular sieves and packings used have a large consumption, and a lot of waste is generated and difficult to handle.

[0005] (3) The quality of the effluent is affected by the lifespan of materials such as molecular sieves and packings, resulting in large fluctuations and difficulty in meeting standards. Summary of the Invention

[0006] The main objective of this invention is to solve the aforementioned problems in existing coking rainwater treatment processes and to provide a carbon basket specifically designed for removing benzene compounds from initial coking rainwater. This basket utilizes contact adsorption to separate benzene compounds from coking wastewater and then uses an electric heater to desorb and separate the benzene compounds, thereby achieving the transfer of benzene compounds from initial coking rainwater to the gaseous state. Combined with a series of subsequent treatments, the removal and purification of benzene compounds are ultimately achieved efficiently and at low cost.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a carbon basket, comprising a fine grid and a fiber carbon layer arranged on the surface of the fine grid, wherein the fiber carbon layer is woven from fiber carbon filaments. The fiber carbon filaments have a multi-layer structure, including at least a steel wire bottom layer and a semi-coke powder outer layer. The fine grid can provide support for the fiber carbon layer to a certain extent, and the fiber carbon layer is mainly used to adsorb and separate benzene series compounds from rainwater in the early stage of coking.

[0008] In the above scheme, the carbon fiber filament also includes a cotton fiber intermediate layer, and the two sides of the cotton fiber intermediate layer are bonded and fixed to the outer layer of semi-coke powder and the bottom layer of steel wire respectively by adhesive material.

[0009] In the above scheme, the carbon basket also includes a motor, which is connected to the carbon basket and drives it to rotate, thereby driving the fine grid and the fiber carbon layer to rotate synchronously. By using the motor to drive the carbon basket to rotate, all parts of the fiber carbon layer can come into contact with the rainwater in the early stage of coking and adsorb and separate the benzene series compounds therein, ensuring that the carbon basket is fully utilized.

[0010] In the above scheme, the carbon basket also includes a matching heating device and a suction device. The heating device is positioned directly above the fibrous carbon layer of the carbon basket and is used to heat the fibrous carbon layer so that the adsorbed benzene compounds are desorbed and converted into a gaseous state. The suction device is arranged above the carbon basket and is used to collect the benzene compound waste gas generated after heating and desorption.

[0011] In the above scheme, the heating device includes an electric heater. The electric heater is positioned directly opposite the fine grid of the charcoal basket, and the two are matched in size (i.e., of equal width).

[0012] In the above scheme, the suction device includes a booster fan and an electric heating hood. The electric heater is fixed on the electric heating hood, and a circular air intake is provided at the top of the electric heating hood. The booster fan is connected to the circular air intake of the electric heating hood through a pipe. The electric heater heats the fiber carbon layer of the carbon basket, and the benzene series compounds adsorbed on the fiber carbon layer are heated and turned into waste gas. The booster fan extracts and collects the benzene series compound vapors for appropriate treatment.

[0013] In the above scheme, the carbon basket also includes a matching activated carbon bed and a spraying device. The booster fan transports the collected benzene series waste gas to the activated carbon bed for adsorption, and discharges it after reaching the standard. The spraying device sprays water onto the activated carbon bed to regenerate the activated carbon, and the sprayed wastewater is transported to the coking phenol-cyanide wastewater treatment system for deep oxidation treatment, thereby achieving the removal and purification of benzene series compounds in the wastewater.

[0014] In the above scheme, the number of fixed activated carbon beds is at least two sets, thereby realizing cyclical alternating adsorption and regeneration, ensuring the continuity of the entire treatment process.

[0015] The second objective of this invention is to utilize the aforementioned carbon basket to remove benzene compounds from the initial rainwater during coking, comprising: placing the carbon basket in the initial rainwater flow during coking, partially immersing its fine grid and fiber carbon layer in the water, using the fiber carbon layer to adsorb and separate the benzene compounds in the initial rainwater during coking, using a heating device to heat the fiber carbon layer to convert the benzene compounds into waste gas, and using a suction device to collect the benzene compound waste gas and transport it to an activated carbon bed for treatment.

[0016] In the above scheme, at least two carbon baskets are dispersed at a certain distance in the flow of rainwater during the initial coking stage. By using multiple carbon baskets to adsorb the rainwater flowing through the coking stage, benzene compounds are effectively separated. This ensures the overall purification efficiency of the carbon baskets and allows for the replacement of the fiber carbon layer by lifting a portion of the carbon basket when the fiber carbon layer is damaged, thereby ensuring that the pollutants in the water treatment system consistently meet the standards.

[0017] In the above scheme, coarse and fine screens are also arranged upstream of the rainwater flow in the early stage of coking, which are used to physically intercept coarse and fine floating objects and benzene series compounds in the water multiple times.

[0018] In the above scheme, the initial rainwater from coking, after being treated by carbon basket adsorption, passes through a grit chamber, a coagulation sedimentation tank, a V-shaped filter, a chlorine disinfection tank, and a clear water tank in sequence before being discharged in compliance with standards or reused.

[0019] This invention utilizes the low solubility of benzene compounds in water and their ease of adsorption and adhesion to solids. Through dynamic contact between the solids and water, benzene compounds are transferred from the water to the surface of the solids. Furthermore, taking advantage of the low boiling points of benzene compounds and the high boiling points of the solids, heating is used to desorb and peel the benzene compounds from the solid surface, removing them from initial rainwater and subjecting them to appropriate treatment, ultimately achieving compliant discharge of initial rainwater from coking operations.

[0020] Compared with existing similar products or technologies, the advancements of this invention are mainly reflected in the following aspects: (1) The benzene series compounds in the initial rainwater of coking are separated by adsorption of carbon baskets, and then desorbed by electric heating device. This achieves the purpose of transferring benzene series compounds from the initial rainwater to the gaseous state. Only by increasing or decreasing the number of carbon baskets can different water treatment volumes be adapted. This completely solves the problems of large land area and high investment faced by traditional methods when treating large amounts of rainwater.

[0021] (2) The benzene series compounds were transformed from gaseous to liquid state by activated carbon adsorption and spray regeneration. The wastewater containing benzene series compounds generated by spraying was sent to the coking phenol cyanide wastewater treatment system for deep treatment, which achieved the removal and purification of benzene series compounds. This not only achieved the standard discharge, but also solved a series of problems existing in the current water treatment technology, such as large consumption of molecular sieves and packings, large amount of waste generated and difficult treatment.

[0022] (3) By setting up multiple sets of carbon baskets in a dispersed manner, the overall purification efficiency can be guaranteed, and the fiber layer can be replaced by lifting the carbon basket when the fiber carbon layer is damaged. This overcomes the problems of the existing technology, such as the effluent water quality being affected by the material lifespan, large fluctuations in effluent water quality, and difficulty in meeting standards.

[0023] (4) The whole treatment method has the advantages of simple operation, low cost and good effect, and achieves the standard discharge of rainwater in the early stage of coking, which greatly reduces the environmental protection pressure of enterprises. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the processing method described in this invention.

[0025] Figure 2 This is a schematic diagram of the structure of the carbon basket described in this invention.

[0026] Attached reference numerals: 1-coarse screen, 2-fine screen, 3-carbon basket, 4-sedimentation tank, 5-coagulation sedimentation tank, 6-V-shaped filter, 7-chlorine disinfection tank, 8-electric heating cover, 9-air intake, 10-activated carbon bed, 11-booster fan, 12-fine screen bar, 13-fiber carbon, 14-electric heater, 15-insulation cotton, 16-galvanized sheet. Detailed Implementation

[0027] To enable those skilled in the art to fully understand the purpose, technical solution, and beneficial effects of this invention, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be emphasized that the illustrative embodiments and descriptions listed herein are for illustrative purposes only and do not constitute any limitation on the invention.

[0028] It should also be noted that, to avoid obscuring the invention with unnecessary details, the accompanying drawings only show structures and / or method steps closely related to the technical solutions of the present invention, while omitting other details that are not closely related to the present invention. The term "comprising / including" herein indicates the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components. Unless otherwise specified, the terms "connected" or "linked" can refer not only to a direct connection but also to an indirect connection or a wireless connection involving an intermediary.

[0029] Unless otherwise stated, the descriptions of orientation or positional relationships in this invention, such as "upper," "lower," "left," "right," "front," and "rear," are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the purpose of facilitating the description of this invention and simplifying the description. They are not intended to indicate or imply that the system or element referred to must have a specific orientation or be constructed or operated in a specific orientation, and should not be construed as limiting the technical solution of this invention.

[0030] The process method for removing benzene series compounds from rainwater during the initial stage of coking in this invention is as follows: Figure 1 As shown, the specific process is as follows: Rainwater from the initial coking stage is collected and transported directionally. Along the waterway, coarse screens 1, fine screens 2, and multiple (e.g., 2-6 sets) of carbon baskets 3 are sequentially installed. Coarse screens 1 physically intercept large floating objects and benzene compounds in the water. Fine screens 2 then physically intercept fine floating objects and benzene compounds a second time. Finally, carbon baskets 3 repeatedly physically intercept and adsorb benzene compounds in the water. After carbon basket adsorption treatment, the benzene content in the wastewater is significantly reduced, ensuring that subsequent wastewater meets discharge or reuse requirements. The treated wastewater then sequentially enters the traditional water treatment unit's sedimentation tank 4, coagulation sedimentation tank 5, V-type filter 6, chlorine disinfection tank 7, and clear water tank for further treatment. The purified water in the clear water tank can be directly discharged in compliance with standards or used for internal plant recirculation.

[0031] After the carbon basket 3 becomes saturated with adsorption, it is heated to increase its temperature. The benzene compounds adsorbed on the carbon basket 3 are converted into waste gas upon heating. Under the suction of the booster fan 11, this waste gas is transported to the activated carbon bed 10, where it is adsorbed and separated, and then discharged into the atmosphere in compliance with standards. After the activated carbon bed 10 becomes saturated, it is regenerated by spraying industrial water. The sprayed wastewater is then sent to the coking phenol and cyanide wastewater treatment system for deep oxidation treatment, thereby achieving wastewater discharge that meets standards.

[0032] The most critical processing equipment in the entire process is the carbon basket 3, whose structural diagram is shown below. Figure 2 As shown. The main function of the carbon basket 3 is to control the concentration of benzene compounds in the rainwater during the initial stage of coking. During operation, multiple carbon baskets 3 are usually distributed in the water path, all located after the fine screen 2 and before the sedimentation tank 4. The carbon basket 3 includes a traditional fine screen and a layer of fibrous carbon 13 wrapped around the surface of the fine screen bars 12. The fine screen and the fibrous carbon layer are driven to rotate synchronously by a motor to achieve cyclic adsorption and separation.

[0033] Fiber carbon 13 is woven from fiber carbon filaments, which are composed of various materials bonded together. The bottom layer is fine steel wire (diameter φ 0.2-0.4μm, material 304 or 316L), the middle layer is cotton fiber (quality standard refers to GB / T19635), and the outer layer is semi-coke powder. Adjacent layers are bonded together with an adhesive liquid (i.e., glue, quality standard refers to GB / T 19340). To prepare the fiber carbon filaments, an adhesive liquid is first applied to the surface of the fine steel wire, then cotton fiber is bonded on top. Next, an adhesive liquid is applied to the surface of the cotton fiber, and then semi-coke powder (particle size <3μm > 90%) is bonded on top. The mixture is then air-dried to form fiber carbon filaments, which are then used to weave the fiber carbon layer.

[0034] An electric heating hood 8 is installed above the carbon basket 3, positioned above the water surface. An electric heater 14 is installed on the inner wall of the electric heating hood 8, which is also wrapped with insulation cotton 15 and galvanized steel plate 16. The electric heating hood 8 is mainly used to heat the fiber carbon layer, thereby converting the adsorbed benzene compounds into waste gas. The electric heating hood 8 has an air intake 9, through which the benzene compound waste gas generated from heating the carbon basket 3 is drawn into the activated carbon bed 10 for adsorption and separation.

[0035] Example 1 (1) The initial rainwater collected in the coking plant area first passes through coarse screen 1, where large floating objects and benzene compounds in the water are physically intercepted. The treated rainwater then enters fine screen 2, where fine floating objects and benzene compounds in the water are physically intercepted a second time. After that, the rainwater passes through 2-3 sets of carbon baskets 3, where benzene compounds in the water are physically intercepted multiple times. The rainwater treated in this way flows through sedimentation tank 4, coagulation sedimentation tank 5, V-type filter 6, chlorine disinfection tank 7, and clear water tank in sequence before being used for replenishing the plant's circulating water.

[0036] (2) The charcoal basket 3 is fully or partially submerged in water and rotated by a motor. An electric heating cover 8 is installed 100-200mm above the water surface above the charcoal basket 3. The tilt angle of the electric heating cover 8 is 55-65°, and the tilt angle between the fine grid of the charcoal basket 3 and the water surface is equal to the tilt angle of the electric heating cover. The outer wall of the electric heating cover 8 is insulated with 20-30mm thick insulation cotton 15, and then wrapped with a 0.6-0.8mm thick galvanized sheet. An electric heater 14 is also installed on the inner wall of the electric heating cover 8. The width of the electric heater 14 is equal to the width of the grid of the charcoal basket 3. A circular air intake 9 is provided at the top of the electric heating cover 8. The diameter of the air intake 9 is determined by the area of ​​the electric heating cover 8, and is approximately 1 / 30-1 / 33 of its area. After the fiber carbon layer on the carbon basket 3 is saturated with adsorption, the electric heater 14 and the booster fan 11 are started, and the benzene series waste gas generated by thermal desorption is directionally transported to the activated carbon bed 10 through the air inlet 9.

[0037] (3) After the benzene series compounds in the waste gas are adsorbed by the fixed activated carbon bed 10, the remaining qualified gas is pressurized by the booster fan 11 and discharged into the atmosphere. The activated carbon bed 10 is arranged horizontally, with two towers connected in parallel, one for adsorption and one for regeneration. The thickness of the carbon bed is about 1000-2000 mm, and the gas flow velocity on the surface of the activated carbon does not exceed 0.6 m / s. In order to ensure the adsorption effect, the activated carbon is replaced once a year, and the quality standard of the activated carbon refers to the national standard GB / T 12496. The replaced activated carbon is sent to the coking coal blending and coking to achieve the harmless treatment of waste activated carbon.

[0038] The activated carbon after adsorption is periodically regenerated by spraying industrial water, with the volume ratio of spray water to waste gas being approximately 1:100,000 to 1:130,000. The wastewater after spraying and washing is collected and sent to the coking phenol and cyanide wastewater treatment system for deep oxidation treatment to ensure that the benzene series compounds in the wastewater are reduced to the emission requirements.

[0039] Example 2 The initial rainwater from a coking plant with a production capacity of 1 million tons was treated using the method described in Example 1. The thickness of the activated carbon bed 10 was approximately 1300 mm, the gas flow velocity on the activated carbon surface was 0.6 m / s, and the volume ratio of sprayed water to waste gas was approximately 1:100000.

[0040] Sampling and testing results showed that the benzene content in the initial rainwater from the coking plant before treatment was 0.3 μm / L, while the benzene content in the water flowing out of the clear water tank after treatment was less than 0.03 μm / L. This indicates that the method of the present invention can completely remove the initial rainwater from a coking plant with a production capacity of 1 million tons, achieving compliant discharge or reuse.

[0041] Example 3 The initial rainwater from a coking plant with a production capacity of 2 million tons was treated using the method described in Example 1. The thickness of the activated carbon bed 10 was approximately 1500 mm, the gas flow velocity on the activated carbon surface was 0.5 m / s, and the volume ratio of sprayed water to waste gas was approximately 1:110000.

[0042] Sampling and testing results showed that the benzene series compounds in the initial rainwater of the coking plant before treatment were approximately 0.15 μm / L, while no benzene series compounds were detected in the water flowing out of the clear water pool after treatment. This indicates that the method of the present invention can completely remove the initial rainwater from a coking plant with a production capacity of 2 million tons, and can achieve compliant discharge or reuse.

[0043] In summary, the carbon basket and corresponding treatment method provided by this invention have advantages such as simple operation, low cost and good effect in practical applications. They can achieve the standard discharge of rainwater in the early stage of coking, and reduce the wastewater treatment and environmental protection pressure of enterprises.

Claims

1. A carbon basket for removing benzene compounds from rainwater during the initial stage of coking, characterized in that: The carbon basket includes a grid and a fiber carbon layer arranged on the surface of the grid. The fiber carbon layer is woven from fiber carbon filaments, and the fiber carbon filaments include at least a metal wire bottom layer and a carbon powder outer layer.

2. The charcoal basket as described in claim 1, characterized in that: The fiber carbon filament also includes a fiber intermediate layer, and the two sides of the fiber intermediate layer are respectively bonded and fixed to the carbon powder outer layer and the metal wire bottom layer.

3. The charcoal basket as described in claim 1, characterized in that: The carbon basket also includes a motor, which is directly or indirectly connected to the grid and the fiber carbon layer and drives them to rotate.

4. The charcoal basket as described in claim 1, characterized in that: The charcoal basket also includes a matching heating device and a suction device. The heating device is positioned directly above the fibrous charcoal layer of the charcoal basket, and the suction device is arranged above the charcoal basket.

5. The charcoal basket as described in claim 4, characterized in that: The heating device includes an electric heater, and the suction device includes a booster fan and an electric heating cover. The electric heater is fixed on the electric heating cover, and an air intake is provided on the electric heating cover. The booster fan is connected to the air intake of the electric heating cover through a pipe.

6. The charcoal basket as described in claim 4, characterized in that: The carbon basket also includes a matching activated carbon bed, a spraying device, and a coking phenol and cyanide wastewater treatment system. The suction device draws the waste gas to the activated carbon bed for adsorption treatment, the spraying device sprays water onto the activated carbon bed for regeneration, and the sprayed wastewater is transported to the coking phenol and cyanide wastewater treatment system for deep oxidation treatment.

7. The charcoal basket as described in claim 6, characterized in that: There are at least two sets of activated carbon beds to facilitate alternating adsorption and regeneration.

8. A method for removing benzene compounds from rainwater during the initial stage of coking using a carbon basket, characterized in that... The method includes: placing a carbon basket in the rainwater flow during the initial stage of coking, partially immersing its grid and fiber carbon layer in the water, using the fiber carbon layer to adsorb and separate benzene series compounds in the rainwater during the initial stage of coking, using a heating device to heat the fiber carbon layer to desorb the benzene series compounds and convert them into waste gas, and using a suction device to collect the waste gas and transport it to an activated carbon bed for treatment.

9. The method as described in claim 8, characterized in that: There are at least two charcoal baskets, which are distributed in the rainwater flow during the initial stage of coking.

10. The method as described in claim 8, characterized in that: Coarse and fine screens are arranged upstream of the rainwater flow during the initial coking stage. After being treated by carbon basket adsorption, the rainwater from the initial coking stage is discharged or reused after further treatment. The subsequent treatment includes at least one of grit removal, coagulation sedimentation, filtration, and disinfection.

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