System and working method for separating carbon sand from sludge carbon and simultaneously expanding carbon hole

Abstract

The application discloses a system and working method for separating carbon sand from sludge carbon and synchronously expanding the carbon hole, which comprises a tank body, a rotating mechanism, a sludge carbon releasing mechanism, a secondary reverse mixing mechanism and a water outlet weir, a sand collecting hopper is installed at the bottom end of the tank body, a sand discharging pipe is connected to the lower end of the sand collecting hopper, the sludge carbon releasing mechanism is installed inside the tank body and above the sand collecting hopper, a carbon inlet is formed in the side wall bottom end of the sludge carbon releasing mechanism, a carbon inlet pipe is connected to the carbon inlet, the inlet of the carbon inlet pipe is located outside the tank body, the rotating mechanism is installed above the sludge carbon releasing mechanism, a water inlet pipe is connected to the inlet of the rotating mechanism, the secondary reverse mixing mechanism is installed above the rotating mechanism, the water outlet weir is arranged above the secondary reverse mixing mechanism, and the water outlet weir is connected with the inner wall of the tank body. The application realizes the effective separation of carbon powder and sand and stone from sludge carbon, simultaneously realizes the expansion of the carbon hole and the removal of part of the ash, increases the specific surface area of the carbon, and improves the adsorption performance of the carbon.

Description

Technical Field

[0001] This invention relates to the field of sludge carbon treatment technology, and in particular to a system and working method for separating carbon and sand and simultaneously expanding carbon pores in sludge carbon. Background Technology

[0002] Sludge is a byproduct of wastewater treatment, concentrating 30% to 50% of pollutants from wastewater. It is a complex heterogeneous body composed of organic debris, bacterial cells, inorganic particles, and colloidal sludge. The main characteristics of sludge are a water content generally above 90%, reaching up to 99%, fine particles, low specific gravity, and a colloidal liquid state. Sludge has a high organic content, complex composition, and is prone to putrefaction and foul odor. Sludge carbonization is a sludge stabilization process that involves pyrolysis under anaerobic or anoxic conditions to obtain carbon-containing solid products. During carbonization, organic matter decomposes, producing products including pyrolysis gas (composed of low-molecular-weight organic matter and water vapor), tar, and biochar—a solid carbonaceous material mainly composed of fixed carbon and inorganic matter.

[0003] Biochar prepared from sludge is usually a mixture containing carbon and sand. The large amount of sand in biochar affects its further application. How to achieve efficient separation of carbon and sand in biochar is an important research topic in the field of biochar application. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a system and method for separating biochar and sand in sludge biochar and simultaneously expanding the pores of the biochar, achieving two goals at once.

[0005] A system for separating carbon and sand in sludge carbon and simultaneously expanding carbon pores according to the present invention includes a tank, a swirl mechanism, a sludge carbon release mechanism, a secondary backmixing mechanism, and an effluent weir. A sand collection hopper is installed at the bottom of the tank, and a sand discharge pipe is connected to the lower end of the sand collection hopper. The sludge carbon release mechanism is installed inside the tank, above the sand collection hopper. A carbon inlet is opened at the bottom of the side wall of the sludge carbon release mechanism, and a carbon inlet pipe is connected to the carbon inlet. The inlet of the carbon inlet pipe is located outside the tank. The swirl mechanism is installed above the sludge carbon release mechanism, and a water inlet pipe is connected to the inlet of the swirl mechanism. The secondary backmixing mechanism is installed above the swirl mechanism. The effluent weir is located above the secondary backmixing mechanism and is connected to the inner wall of the tank. An effluent pipe is connected to the outer side of the tank at the location of the effluent weir.

[0006] Preferably, the sludge carbon release mechanism includes a triangular cone, with multiple sets of external discharge ports evenly opened on the upper part of the cone surface, and the carbon inlet pipe connected to the lower part of the cone surface.

[0007] Preferably, a cover plate is connected to the upper end of the external discharge outlet through a hinge, and the opening degree of the cover plate is 0-85°.

[0008] Preferably, the swirling mechanism includes multiple layers of guide vanes in a spiral shape. The multiple layers of guide vanes are connected to the inner wall of the tank body. An inlet pipe connection port is provided at the inlet of the guide vane on the inner wall of the tank body. The inlet pipe is connected to the inlet pipe connection port. The connection between the inlet pipe and the inner wall of the tank body is tangent. The inclination angle of the inlet of the guide vane is the same as the inclination angle of the inlet pipe.

[0009] Preferably, the interval between multiple groups of the guide vanes is D 管 / n, where D 管 represents the diameter of the inlet pipe, and n represents the number of layers of the guide vanes.

[0010] Preferably, the secondary backmixing mechanism includes a baffle in a triangular solid strip shape, and the baffle is connected to the inner wall of the tank body.

[0011] Preferably, the inlet height of the carbon inlet pipe is higher than the installation height of the water outlet weir.

[0012] Preferably, a working method of the system for carbon sand separation and simultaneous carbon pore expansion in sludge carbon is as follows:

[0013] S1: Introduce the sludge carbon into the triangular cone from the inlet of the carbon inlet pipe;

[0014] S2: Introduce an acidic aqueous solution with a flow rate of S from the inlet pipe, where the pH value of the acidic aqueous solution is b;

[0015] S3: The acidic aqueous solution flows through the guide vanes and forms a swirling flow after passing through the guide vanes. The swirling flow has a centrifugal acceleration of a:

[0016]

[0017]

[0018] where a is the centrifugal acceleration, with the unit of m / s 2 ; k is an adjustment coefficient; S is the flow rate in the sewage inlet pipe, with the unit of m / s; D is the diameter of the tank body, with the unit of m; ρ 砂 is the true density of the sand, with the unit of kg / m 3 ; ρ 炭 is the true density of the carbon, with the unit of kg / m 3 ; b is the pH value of the acidic aqueous solution, and 0 < b < 7; l is the length of the guide vane, with the unit of m; h is the height from the starting point to the ending point of the guide vane, with the unit of m;

[0019] S4: Due to the swirling effect, a negative pressure is formed in the center, and the sludge carbon is drawn into the triangular cone and led out from the external discharge port. Swirling and collisions occur between particles in the tank. Due to the different centrifugal forces, the carbon powder with a lower density rises with the water flow and is led out from the outlet weir. The sand with a higher density is subjected to the dual action of centrifugal force and gravity, accumulates on the inner wall of the tank and flows downward, collecting in the sand collection hopper and periodically discharged from the tank through the sand discharge pipe.

[0020] Preferably, in step S4, the pore volume of the carbon powder after soaking in acid is c, wherein:

[0021]

[0022] C0 is the initial pore volume of sludge activated carbon, in cm³. 3 / g; b is the pH value of the acidic aqueous solution; a is the centrifugal acceleration in m / s². 2 m and n are process-related parameters, where m = -0.2 and n = 0.1.

[0023] The beneficial effects of this invention are:

[0024] (1) The equipment has a simple structure. Except for the circular cover at the discharge port of sludge and carbon, it is a static equipment, which is convenient for management and maintenance.

[0025] (2) By using swirling flow, a negative pressure is formed in the center, which draws the sludge carbon into the tank. Swirling flow and collisions between particles are formed in the tank. Due to the different centrifugal forces, the carbon powder has a lower density and rises with the water flow, flowing out of the tank from the top weir. The sand has a higher density and is subject to the dual action of centrifugal force and gravity. It accumulates on the inner wall of the tank and flows downward, collecting in the sand collection hopper and being discharged out of the tank periodically, thus achieving effective separation of carbon powder and sand in the sludge carbon.

[0026] (3) Carbon and sand are separated by cyclone, and carbon powder is soaked in acid solution, which can expand the pores of carbon and remove some ash, increase the specific surface area of ​​carbon and improve the adsorption performance of carbon. Attached Figure Description

[0027] In the attached diagram:

[0028] Figure 1 This is a schematic diagram of the structure of a system for separating carbon and sand in sludge carbon and simultaneously expanding carbon pores, as proposed in this invention.

[0029] Figure 2 The present invention proposes Figure 1 Sectional view of AA in the middle;

[0030] Figure 3 The present invention proposes Figure 1 Cross-sectional view of the middle section (BB);

[0031] Figure 4 This is a schematic diagram of the triangular pyramidal portion proposed in this invention.

[0032] In the diagram: 1-Tank body, 2-Water inlet pipe, 3-Carbon inlet pipe, 4-Triangular cone, 5-Cover plate, 6-External discharge outlet, 7-Water outlet weir, 8-Water outlet pipe, 9-First valve, 10-Guide plate, 11-Sand collection hopper, 12-Sand discharge pipe, 13-Second valve, 14-Baffle, 15-Third valve. Detailed Implementation

[0033] Reference Figure 1 A system for separating carbon and sand in sludge carbon and simultaneously expanding carbon pores includes a tank 1, a swirl mechanism, a sludge carbon release mechanism, a secondary backmixing mechanism, and an effluent weir 7. A sand collection hopper 11 is installed at the bottom of the tank 1, and a sand discharge pipe 12 is connected to the lower end of the sand collection hopper 11. The sludge carbon release mechanism is installed inside the tank 1 above the sand collection hopper 11. A carbon inlet is opened at the bottom of the side wall of the sludge carbon release mechanism, and a carbon inlet pipe 3 is connected to the carbon inlet. The inlet of the carbon inlet pipe 3 is located outside the tank 1. The swirl mechanism is installed above the sludge carbon release mechanism, and an inlet pipe 2 is connected to the inlet of the swirl mechanism. The secondary backmixing mechanism is installed above the swirl mechanism. The effluent weir 7 is located above the secondary backmixing mechanism and is connected to the inner wall of the tank 1. An effluent pipe 8 is connected to the outer side of the tank 1 at the position of the effluent weir 7.

[0034] The sludge carbon release mechanism includes a triangular cone 4, with multiple sets of external discharge ports 6 evenly distributed on the upper part of the cone surface of the triangular cone 4, and a carbon inlet pipe 3 connected to the lower part of the cone surface of the triangular cone 4.

[0035] The upper end of the external discharge port 6 is connected to a cover plate 5 via a hinge, and the opening degree of the cover plate 5 is 0-85°.

[0036] The swirl mechanism includes a spiral multi-layer guide vane 10, which is connected to the inner wall of the tank 1. The inner wall of the tank 1 has an inlet pipe connection port at the inlet of the guide vane 10. The inlet pipe 2 is connected to the inlet pipe connection port and is tangent to the inner wall of the tank 1. The inlet tilt angle of the guide vane 10 is the same as the tilt angle of the inlet pipe 2.

[0037] The spacing between the multiple sets of guide vanes 10 is D. 管 / n, where D 管 'n' represents the diameter of the inlet pipe, and 'n' represents the number of layers of guide vanes.

[0038] The secondary reverse mixing mechanism includes a triangular solid strip baffle 14, which is connected to the inner wall of the tank 1.

[0039] The inlet height of the carbon inlet pipe 3 is higher than the installation height of the outlet weir 7.

[0040] The working method of the system for separating carbon sand from sludge carbon and simultaneously expanding carbon pores is as follows:

[0041] S1: Introduce the sludge carbon into the triangular cone 4 through the inlet of the carbon inlet pipe 3;

[0042] S2: Introduce an acidic aqueous solution with a flow rate of S from the water inlet pipe, where the pH value of the acidic aqueous solution is b;

[0043] S3: The acidic aqueous solution flows through the guide plate 10 and forms a swirl after passing through the guide plate 10. The centrifugal acceleration of the swirl is a:

[0044]

[0045]

[0046] Where a is the centrifugal acceleration, with the unit of m / s 2 ; k is the adjustment coefficient; S is the flow rate in the sewage inlet pipe, with the unit of m / s; D is the diameter of the tank body, with the unit of m; ρ 砂 is the true density of the sand, with the unit of kg / m 3 ; ρ 炭 is the true density of the carbon, with the unit of kg / m 3 ; b is the pH value of the acidic aqueous solution, and 0 < b < 7; l is the length of the guide plate, with the unit of m; h is the height from the starting point to the ending point of the guide plate, with the unit of m;

[0047] S4: Due to the effect of the swirl, a negative pressure is formed in the center. The sludge carbon is sucked into the triangular cone 4 and led out through the external discharge outlet 6. A swirl is formed in the tank body 1 and collisions occur between particles. Due to different centrifugal forces, the carbon powder has a small density and rises with the water flow, and is led out from the water outlet weir 7. The sand has a larger density and is affected by the dual action of centrifugal force and gravity. It accumulates on the inner wall of the tank body 1 and flows downward, gathering in the sand collecting hopper 11 and being regularly discharged out of the tank through the sand discharge pipe 12;

[0048] In step S4, the pore volume of the carbon powder after being soaked in the acid solution is c, where:

[0049]

[0050] C0 is the initial pore volume of the sludge carbon, with the unit of cm 3 / g; b is the pH value of the acidic aqueous solution; a is the centrifugal acceleration, with the unit of m / s 2 ; m and n are process-related parameters, m = -0.2, n = 0.1.

[0051] Example 1:

[0052] This embodiment includes the following steps: 1 kg of sludge with a moisture content of 99.6% produced by a municipal wastewater treatment plant is concentrated by gravity, reducing the moisture content to 96%. 20% lime (by dry weight of the sludge) and 0.3% cationic polyacrylamide are added. The sludge is then dewatered using a plate and frame filter press, reducing the moisture content to 80%. The dewatered sludge is then fed into a sludge carbonization furnace, dried, and carbonized at 350℃ for 3 hours to obtain 0.2 kg of sludge carbon with a specific surface area of ​​120 μm. 2 / g, pore volume 1.02cm 3 / g.

[0053] The sludge was treated using a carbon-sand separation and simultaneous pore-expansion process. The acidic water had a pH of 3 and a centrifugal acceleration of 294.3 m / s². 2 With a hydraulic retention time of 3 minutes, 0.14 kg of carbon and 0.06 kg of sand were recovered. The specific surface area of ​​the recovered carbon was 142 m². 2 / g, pore volume 1.13cm 3 / g, the specific surface area increased by 18.3%, and the pore volume was calculated to be 1.15cm³ using an empirical formula. 3 / g, with a relative error of 1.8% compared to the experimental value, which is within the acceptable range.

[0054] Example 2:

[0055] This embodiment includes the following steps: 0.7 kg of sludge with a moisture content of 99.8% produced by a wastewater treatment plant in an industrial park, and 0.3 kg of iron sludge with a moisture content of 96% produced by the Fenton process. The mixed sludge is concentrated by gravity, reducing the moisture content by 95%. 20% lime (based on the dry weight of the sludge) and 0.3% cationic polyacrylamide are added. The mixture is then dewatered using a plate and frame filter press, reducing the moisture content to 78%. The dewatered sludge is then fed into a sludge carbonization furnace, dried, and carbonized at 600℃ for 2 hours to obtain 0.12 kg of sludge carbon with a specific surface area of ​​90 μm. 2 / g, pore volume 0.99cm 3 / g.

[0056] The sludge was treated using a carbon-sand separation and simultaneous pore-expansion process, with acidic water pH=5 and a centrifugal acceleration of 490.5 m / s. 2 The hydraulic retention time was 3 minutes, and 0.05 kg of carbon and 0.07 kg of sand were recovered. The specific surface area of ​​the recovered carbon was 102 m². 2 / g, pore volume 1.03cm 3 / g, the specific surface area increased by 13.3%, and the pore volume was calculated to be 1.06cm³ using an empirical formula. 3 / g, with a relative error of 2.9% compared to the experimental value, which is within the acceptable range.

Claims

1. A system for separating carbon sand from sludge carbon and simultaneously expanding carbon pores, characterized in that: The system includes a tank (1), a swirl mechanism, a sludge carbon release mechanism, a secondary back-mixing mechanism, and an effluent weir (7). A sand collection hopper (11) is installed at the bottom of the tank (1), and a sand discharge pipe (12) is connected to the lower end of the sand collection hopper (11). The sludge carbon release mechanism is installed inside the tank (1) above the sand collection hopper (11). A carbon inlet is opened at the bottom of the side wall of the sludge carbon release mechanism, and a carbon inlet pipe (3) is connected to the carbon inlet. The inlet of the carbon inlet pipe (3) is located outside the tank (1). The swirl mechanism is installed above the sludge carbon release mechanism, and a water inlet pipe (2) is connected to the inlet of the swirl mechanism. The secondary back-mixing mechanism is installed above the swirl mechanism. The effluent weir (7) is located above the secondary back-mixing mechanism. The effluent weir (7) is connected to the inner wall of the tank (1), and an effluent pipe (8) is connected to the outer side of the tank (1) at the position of the effluent weir (7). The sludge carbon release mechanism includes a triangular cone (4), and multiple sets of external discharge ports (6) are evenly opened on the upper part of the cone surface of the triangular cone (4). The carbon inlet pipe (3) is connected to the lower part of the cone surface of the triangular cone (4). The swirl mechanism includes a spiral-shaped multi-layered guide vane (10), which is connected to the inner wall of the tank (1). The inner wall of the tank (1) is provided with a water inlet at the inlet of the guide vane (10). The water inlet pipe (2) is connected to the water inlet. The water inlet pipe (2) is tangent to the inner wall of the tank (1). The inlet tilt angle of the guide vane (10) is the same as the tilt angle of the water inlet pipe (2).

2. The system for separating carbon sand and simultaneously expanding carbon pores in sludge carbon according to claim 1, characterized in that: The upper end of the external discharge port (6) is connected to a cover plate (5) via a hinge, and the opening degree of the cover plate (5) is 0-85°.

3. The system for separating carbon sand and simultaneously expanding carbon pores in sludge carbon according to claim 1, characterized in that: The spacing between the multiple sets of guide vanes (10) is D. 管 / n, where D 管 'n' represents the diameter of the inlet pipe, and 'n' represents the number of layers of guide vanes.

4. The system for separating carbon sand and simultaneously expanding carbon pores in sludge carbon according to claim 1, characterized in that: The secondary reverse mixing mechanism includes a triangular solid strip baffle (14) connected to the inner wall of the tank (1).

5. The system for separating carbon sand and simultaneously expanding carbon pores in sludge carbon according to claim 1, characterized in that: The inlet height of the carbon inlet pipe (3) is higher than the installation height of the outlet weir (7).

6. The operating method of the system for separating carbon sand and simultaneously expanding carbon pores in sludge carbon according to any one of claims 1-5, characterized in that, The method steps are as follows: S1: The sludge carbon is introduced into the triangular cone (4) through the inlet of the carbon inlet pipe (3); S2: An acidic aqueous solution with a flow rate of S is introduced into the inlet pipe, wherein the pH value of the acidic aqueous solution is b; S3: The acidic aqueous solution flows through the guide vane (10) and forms a swirling flow. The centrifugal acceleration of the swirling flow is a: a= ； ； Among them, a is the centrifugal acceleration, with the unit of m / s 2 ; k is the adjustment coefficient; S is the flow velocity in the sewage inlet pipe, with the unit of m / s; D is the diameter of the tank body, with the unit of m; ρ 砂 is the true density of sand, with the unit of kg / m 3 ; ρ 炭 is the true density of carbon, with the unit of kg / m 3 ; b is the pH value of the acidic aqueous solution, and 0 < b < 7; l is the length of the guide plate, with the unit of m; h is the height from the starting point to the ending point of the guide plate, with the unit of m; S4: Due to the effect of swirling flow, a negative pressure is formed in the center. The sludge carbon is drawn into the triangular cone (4) and drawn out from the external discharge port (6). Swirling flow is formed in the tank (1) and collisions occur between particles. Due to the different centrifugal forces, the carbon powder has a low density and rises with the water flow. It is drawn out from the outlet weir (7). The sand has a high density and is affected by both centrifugal force and gravity. It accumulates on the inner wall of the tank (1) and flows downward, gathering in the sand collection hopper (11). It is periodically discharged from the tank through the sand discharge pipe (12).

7. The working method of the system for separating carbon sand and simultaneously expanding carbon pores in sludge carbon according to claim 6, characterized in that, In step S4, the pore volume of the carbon powder after soaking in acid is c, where: c= ； C0 is the initial pore volume of sludge activated carbon, in cm³. 3 / g; b is the pH value of the acidic aqueous solution; a is the centrifugal acceleration in m / s². 2 m=-0.2, n=0.1.

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