A high-efficiency energy-saving sludge dewatering and electricity generation method

Abstract

The application discloses a kind of high-efficiency energy-saving sludge dewatering synchronous power generation methods, belongs to the field of sludge dewatering, to solve the problem of high energy consumption of existing sludge dewatering method.The application is designed and constructed by imitating the transpiration of plants in nature to design and construct dewatering power generation unit, under the evaporation driving action of solar energy, using the designed dewatering power generation unit, the water in the sludge is directional migration in dewatering power generation unit and finally evaporates and disperses, while the water directional migration process induces the formation of ion concentration difference in dewatering power generation unit, generates potential difference, finally recovers the chemical energy of sludge water and water-soluble ions in it in the form of electric energy, to achieve the effect of sludge dewatering synchronous power generation.Compared with the existing method, the application can dewater sludge and realize synchronous power generation without additional energy input.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high efficiency energy-saving sludge dewatering synchronous power generation method, belong to environmental protection technical field. BACKGROUND

[0002] Higher moisture content makes the volume of sludge large, resulting in a series of difficulties such as transportation, treatment, disposal, etc. Therefore, sludge dewatering reduction is particularly necessary. At present, in actual engineering, the main method for sludge dewatering / solid-liquid separation is high-speed centrifugation, plate and frame filter pressing and electro-osmotic dewatering, etc. However, these technologies require high speed, high pressure or input high voltage, so that the energy consumption of the current sludge dewatering process is high. Low energy consumption or even negative energy consumption sludge dewatering technology still needs to be developed. SUMMARY

[0003] In view of the above technical deficiencies, the present application provides a kind of high efficiency energy-saving sludge dewatering synchronous power generation method, which aims to solve the high energy consumption problem in the prior art sludge dewatering technology, by imitating the transpiration of plants in nature, the water in sludge is driven by solar energy to migrate outward, and eventually evaporate and disperse, while recovering the chemical energy contained in the water, to realize sludge dewatering synchronous power generation.

[0004] The present application can be achieved by the following technical approach:

[0005] Including, under the evaporation driving action of solar energy, using the designed dewatering power generation unit, the water in sludge is subjected to directional migration and eventually evaporates and disperses in the dewatering power generation unit, while the water is subjected to directional migration, an ion concentration difference is induced in the dewatering power generation unit, an electric potential difference is generated, and the chemical energy contained in the sludge water and water-soluble ions is recovered in the form of electric energy, achieving the effect of sludge dewatering synchronous power generation.

[0006] Further, the dewatering power generation unit is stacked and fixed from bottom to top by sludge layer, filter cloth, mesh conductive electrode ①, water absorption induced power generation module, evaporation driven power generation module and mesh conductive electrode ② through specific device, wherein the water absorption induced power generation module is composed of moisture power generation material, which makes the water in sludge layer migrate upward by hydrophilic functional group and capillary force, and generates ion gradient during the directional migration and diffusion of water, the evaporation driven power generation module is composed of water-absorbing photothermal material, which converts solar energy into heat energy to further drive water to migrate upward and eventually evaporate and disperse under sunlight, accelerates the solid-liquid separation of sludge, and further induces ion gradient on the water migration path under the action of evaporation, and strengthens the power generation effect.

[0007] Further, the shape of the moisture power generation material as the water absorption induced power generation module is T-shaped, the height of the vertical part of the T-shaped in the vertical direction is 0.1-50 cm, the bottom end of the vertical part is in contact with the sludge layer covered by the mesh conductive electrode ① and the filter cloth, the height of the horizontal straight part of the T-shaped in the vertical direction is 0.01-5 cm, and the top end of the horizontal straight part is in contact with the evaporation driven power generation module. The thickness of the water absorption light-heat material as the evaporation driven power generation module in the vertical direction is 0.1-10 cm, and the bottom end is in contact with the horizontal straight part of the T-shaped moisture power generation material.

[0008] Further, the ratio between the thickness of the water absorption light-heat material as the evaporation driven power generation module in the vertical direction and the height of the moisture power generation material as the water absorption induced power generation module in the vertical direction is 0.1-5.

[0009] Further, the sludge types include residual activated sludge, anaerobic digestion sludge, conditioned sludge, trench sludge, primary sludge, dredging sludge and fecal sludge, the thickness of the sludge layer is 0.01-50 cm, the water content of the sludge is 10%-99%, and the conductivity of the sludge is 0.01 mS / cm-10000 mS / cm.

[0010] Further, the specific device for stacking and fixing is composed of a sludge tank and a dewatering power generation functional tank, wherein the sludge tank is used for placing the sludge layer covered by the filter cloth and the mesh conductive electrode ①, and is nested outside the vertical part of the T-shaped moisture power generation material, the depth is the same as the height of the vertical part of the T-shaped moisture power generation material in the vertical direction, and the cross-sectional dimension is the same as the cross-sectional dimension of the vertical part of the T-shaped moisture power generation material.

[0011] Further, the dewatering power generation functional tank is composed of two parallel upper and lower plates which are fixed and assembled by screws and nuts at the four corners of the plates, and is used for pressing the water absorption induced power generation module, the evaporation driven power generation module and the mesh conductive electrode ②, wherein the upper plate is hollowed out into a grid shape to receive solar radiation and to diffuse water vapor, the hollowed-out area accounts for 1 / 6-5 / 6 of the area of the plate, and the lower plate is centrally hollowed out into a square window for locking the horizontal straight part of the T-shaped moisture power generation material, and the area of the square window is smaller than the cross-sectional area of the horizontal straight part of the T-shaped moisture power generation material.

[0012] The beneficial results of the present application are:

[0013] The present application proposes a high-efficiency and energy-saving sludge dewatering and synchronous power generation method, which can realize sludge dewatering and synchronous power generation without additional energy input compared with the current existing method. BRIEF DESCRIPTION OF DRAWINGS

[0014] ATTACHED Figure 1 is a schematic diagram of the dewatering power generation unit described in the present application;

[0015] Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer.

[0016] Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer. Figure 2 Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer.

[0017] Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer.

[0018] Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer. Figure 3 Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer. DETAILED DESCRIPTION

[0019] The present application will be described in detail below with reference to the accompanying drawings and examples, but the drawings and examples involved are only exemplary and do not constitute any limitation on the scope of the present application. Those skilled in the art should understand that the details and forms of the technical solutions of the present application can be modified or replaced without departing from the spirit and scope of the present application, and such modifications and replacements all fall within the protection scope of the present application.

[0020] Figure: 1-mesh electrode ②, 2-evaporation driven power generation module, 3-water absorption induced power generation module, 4-filter cloth, 5-mesh electrode ①, 6-sludge layer. Figure 1 The present application provides a high-efficiency and energy-saving sludge dewatering and synchronous power generation method. Under the evaporation driving action of solar energy, a dewatering power generation unit with a stacking structure is used to make the water in the sludge migrate directionally in the dewatering power generation unit and eventually evaporate and escape. The directional migration of water induces the formation of an ion concentration difference in the dewatering power generation unit, and a potential difference is generated. The chemical energy contained in the water and water-soluble ions in the sludge is recovered in the form of electrical energy, thereby achieving the effect of sludge dewatering and synchronous power generation.

[0021] The dewatering power generation unit is stacked and fixed by a specific device from bottom to top in sequence by a sludge layer, a filter cloth, a mesh conductive electrode ①, a water absorption induced power generation module, an evaporation driven power generation module, and a mesh conductive electrode ②. The water absorption induced power generation module is composed of a moisture power generation material, which makes the water in the sludge in the sludge layer migrate directionally upward by relying on the hydrophilic functional group and capillary force, and generates an ion gradient in the process of directional migration and diffusion of water. The evaporation driven power generation module is composed of a water-absorbing light-thermal material, which converts solar energy into heat energy to further drive the upward migration of water and eventually evaporate and escape under sunlight, thereby accelerating the solid-liquid separation of sludge, and further inducing the ion gradient in the water migration path under the action of evaporation, thereby strengthening the power generation effect.

[0022] The moisture-generating material of the water-absorbing induced power generation module is prepared by gelling a polymer containing oxygen-containing functional groups such as hydroxyl groups in a T-shaped 3D mold. The vertical part of the T-shape has a height of 0.1 to 50 cm in the vertical direction, and the bottom end of the vertical part is in contact with the sludge layer covered by the silver mesh electrode ① and the filter cloth. The horizontal part of the T-shape has a height of 0.01 to 5 cm in the vertical direction, and the top end of the horizontal part is in contact with the evaporation-driven power generation module.

[0023] The water-absorbing photothermal material used as the evaporation-driven power generation module is prepared by doping a light absorber into a hydrophilic polymer. Its thickness in the vertical direction is 0.1 to 10 cm, and its bottom end is in contact with the horizontal and vertical parts of the T-shaped moisture-generating material.

[0024] The ratio between the thickness of the water-absorbing photothermal material in the vertical direction, which serves as the evaporation-driven power generation module, and the height of the moisture-generating material in the vertical direction, which serves as the water-absorbing induced power generation module, is 0.1 to 5.

[0025] The sludge types include residual activated sludge, conditioned residual activated sludge, dredged bottom sludge, and fecal sludge. The sludge layer thickness is 0.01–50 cm, the sludge moisture content is 10%–99%, and the sludge conductivity is 0.01 mS / cm–10000 mS / cm.

[0026] As attached Figure 2 As shown, the specific device for stacking and fixing consists of a sludge tank and a dewatering and power generation functional tank. The sludge tank holds a sludge layer covered with polyethylene filter cloth and silver mesh conductive electrodes ①, nested outside the vertical portion of the T-shaped moisture-generating material. Its depth and cross-sectional dimensions are the same as the vertical height of the T-shaped moisture-generating material. The dewatering and power generation functional tank is assembled from two parallel organic glass plates fixed at the four corners with screws and nuts. This tank is used to press against the water absorption-induced power generation module, the evaporation-driven power generation module, and the silver mesh conductive electrodes ②. The upper plate is perforated into a grid pattern to receive solar radiation and allow water vapor to escape. The perforated area occupies 1 / 6 to 5 / 6 of the plate's area. The lower plate has a square window cut into the center to lock the horizontal portion of the T-shaped moisture-generating material. The area of ​​the square window is smaller than the cross-sectional area of ​​the horizontal portion of the T-shaped moisture-generating material.

[0027] During the water evaporation process, charged ions in the sludge and protons released from polymers upon contact with water form an ion diffusion gradient induced by the directional migration of water, generating voltage at the upper and lower ends of the dewatering power generation unit, thus realizing the function of simultaneous dewatering and power generation.

[0028] The following embodiments further illustrate the specific implementation of the sludge dewatering and simultaneous power generation method of the present invention:

[0029] Example 1

[0030] The residual activated sludge was taken from an anaerobic / aerobic biological reaction process of a Beijing wastewater treatment plant with a daily water treatment capacity of 1 million tons. The moisture content of the sludge was 98.6%. The sludge was settled for 24 hours to obtain sludge with a moisture content of 92%. The sludge was dewatered using the designed dewatering power generation unit (the prepared wet power generation material was named MEG, and the water absorption light and heat material was named LAH). The sludge was filled into a sludge tank to form a sludge layer with a thickness of 0.3 cm. The dewatering process was consistent with that described in the specific embodiment, in which the height of MEG in the vertical direction was 10 cm, and the thickness of LAH was 5 cm. A xenon lamp was used to simulate sunlight irradiation. Under the irradiation of one standard solar intensity, the moisture content of the sludge layer could be reduced to 75.2% after two hours of dewatering. The open circuit voltage between the reticular conductive electrode ① and the reticular conductive electrode ② could be maintained at 0.37 V or higher, as shown in FIG. 1. Figure 3

[0031] Example 2

[0032] The same residual activated sludge as in Example 1 was taken as the original sludge for conditioning. FeCl3·6H2O was added to the sludge at a dosage of 50 mg / g of dry sludge to obtain conditioned sludge. The conditioned sludge was filled into a sludge tank, and the dewatering process was consistent with that described in Example 1. After two hours of dewatering, the moisture content of the sludge layer was reduced to 70.1%. The voltage between the reticular conductive electrode ① and the reticular conductive electrode ②, as well as the current in the circuit, was recorded using a multimeter. It was calculated that the power generation unit could output electrical energy at a power of 506.9 mW per square meter.

[0033] Example 3

[0034] The dredged sludge (moisture content 76.1%) was filled into a sludge tank, and the dewatering process was consistent with that described in Example 1. After two hours of dewatering, the moisture content of the sludge layer was reduced to 56.3%. The voltage between the reticular conductive electrode ① and the reticular conductive electrode ②, as well as the current in the circuit, was recorded using a multimeter. It was calculated that the power generation unit could output electrical energy at a power of 336.1 mW per square meter.

[0035] Example 4

[0036] The fecal sludge (moisture content 90.8%) was filled into a sludge tank, and the dewatering process was consistent with that described in Example 1. After two hours of dewatering, the moisture content of the sludge layer was reduced to 75.8%. The voltage between the reticular conductive electrode ① and the reticular conductive electrode ②, as well as the current in the circuit, was recorded using a multimeter. It was calculated that the power generation unit could output electrical energy at a power of 452.6 mW per square meter.​

Claims

1. A highly efficient and energy-saving method for simultaneous power generation during sludge dewatering, characterized in that, Driven by solar evaporation, a designed dewatering and power generation unit is used to induce the directional migration of water in the sludge, which then evaporates and dissipates. Simultaneously, this directional migration induces an ion concentration gradient within the unit, generating a potential difference. Ultimately, the water in the sludge and the chemical energy contained in its water-soluble ions are recovered as electrical energy, achieving simultaneous power generation during sludge dewatering. The dewatering and power generation unit, from bottom to top, consists of a sludge layer, filter cloth, a mesh conductive electrode 1, a water absorption-induced power generation module, an evaporation-driven power generation module, and a mesh conductive electrode 1. Electrode 2 is stacked and fixed by a specific device. The water-absorbing induced power generation module is made of a moisture-generating material. It relies on hydrophilic functional groups and capillary forces to cause water in the sludge layer to migrate upward in a directional manner. During the directional migration and diffusion of water, an ion gradient is generated. The evaporation-driven power generation module is made of a water-absorbing photothermal material. Under sunlight, it converts solar energy into heat energy to further drive water to migrate upward and eventually evaporate and dissipate, accelerating the solid-liquid separation of sludge. Furthermore, under the action of evaporation, it further induces the generation of an ion gradient along the water migration path, enhancing the power generation effect.

2. The efficient and energy-saving method for simultaneous sludge dewatering and power generation according to claim 1, characterized in that, The moisture-generating material used as the water absorption-induced power generation module is T-shaped. The vertical part of the T-shape has a height of 0.1 to 50 cm in the vertical direction. The bottom end of the vertical part is in contact with the sludge layer covered by the mesh conductive electrode 1 and the filter cloth. The horizontal part of the T-shape has a height of 0.01 to 5 cm in the vertical direction. The top end of the horizontal part is in contact with the evaporation-driven power generation module.

3. The efficient and energy-saving method for simultaneous sludge dewatering and power generation according to claim 1, characterized in that, The water-absorbing photothermal material used as the evaporation-driven power generation module has a thickness of 0.1 to 100 cm in the vertical direction, and its bottom end is in contact with the horizontal and vertical parts of the T-shaped moisture-generating material.

4. The efficient and energy-saving method for simultaneous sludge dewatering and power generation according to claim 1, characterized in that, The ratio between the thickness of the water-absorbing photothermal material in the vertical direction, which serves as the evaporation-driven power generation module, and the height of the moisture-generating material in the vertical direction, which serves as the water-absorbing induced power generation module, is 0.1 to 5.

5. The efficient and energy-saving method for simultaneous sludge dewatering and power generation according to claim 1, characterized in that, The types of sludge include excess activated sludge, anaerobic digestion sludge, conditioning sludge, drainage sludge, primary sedimentation sludge, dredged bottom sludge, and fecal sludge. The sludge layer thickness is 0.01–50 cm, the sludge moisture content is 10%–99%, and the sludge conductivity is 0.01 mS / cm–10000 mS / cm.

6. A highly efficient and energy-saving method for simultaneous sludge dewatering and power generation according to claim 1 or 2, characterized in that, The specific device that plays a stacking and fixing role consists of a sludge tank and a dewatering and power generation functional tank. The sludge tank is used to place the sludge layer covered by filter cloth and mesh conductive electrode 1, and is nested outside the vertical part of the T-shaped wet power generation material. The depth is the same as the height of the vertical part of the T-shaped wet power generation material in the vertical direction, and the cross-sectional dimension is the same as the cross-sectional dimension of the vertical part of the T-shaped wet power generation material.

7. A highly efficient and energy-saving method for simultaneous sludge dewatering and power generation according to claim 6, characterized in that, The dehydration-generating power generation tank is assembled from two parallel plates fixed at the four corners by screws and nuts. It is used to press the water absorption-induced power generation module, the evaporation-driven power generation module, and the mesh conductive electrode 2. The upper plate is hollowed out into a mesh shape to receive solar radiation and release water vapor. The hollowed-out area accounts for 1 / 6 to 5 / 6 of the plate area. The lower plate has a square window cut out in the center to lock the horizontal and vertical parts of the T-shaped moisture-generating material. The area of ​​the square window is smaller than the cross-sectional area of ​​the horizontal and vertical parts of the T-shaped moisture-generating material.

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