A method for continuous monitoring and intelligent regulation of zero liquid discharge of wastewater

Abstract

The present invention provides a method for zero discharge of wastewater with continuous monitoring and intelligent adjustment. The method for zero discharge of wastewater of the present invention includes the following steps: S1: Feed wastewater into an atomizer of an atomizing drying device to atomize it into droplets according to a preset gas-liquid ratio, and at the same time feed high-temperature flue gas into the atomizing drying device; S2: Take real-time samples and weigh the ash in the flue gas before entering the atomizing drying device and after flowing out of the atomizing drying device respectively, and calculate the ash moisture content X of the flue gas after flowing out of the atomizing drying device through the following formula: X = (m2 - m1) / m2; S3: Adjust the gas-liquid ratio of the atomizing drying device according to the ash moisture content X. The method for zero discharge of wastewater of the present invention can detect the ash moisture content X of the flue gas at the outlet of the atomizing drying device in real time and reasonably adjust the operating parameters of the atomizing drying device in a timely manner, which is beneficial to improving the drying effect of wastewater, reducing the energy consumption of the device and ensuring the stable operation of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a zero-emission method for wastewater that can be continuously monitored and intelligently adjusted. Background Art

[0002] During the production and operation process of thermal power plants, a large amount of high-salt wastewater is generated. This type of wastewater has a very high salt content or suspended solid content, and its water quality components are extremely complex. Direct discharge will cause serious environmental pollution. In recent years, the discharge control of industrial wastewater has become increasingly strict, and the zero-emission of high-salt wastewater from thermal power plants has become a hot topic in the industry. Currently, the high-temperature flue gas drying technology is one of the mainstream zero-emission technologies for high-salt wastewater in the industry, and it has the advantages of simple process flow and low operation cost. This technology extracts the high-temperature flue gas from the thermal power plant, atomizes the wastewater and sprays it into the drying tower, so that the wastewater droplets are fully contacted with the high-temperature flue gas, and the wastewater is evaporated and dried by using the waste heat of the flue gas, thus realizing the zero-emission of wastewater. However, the temperature of the high-temperature flue gas in the thermal power plant has a certain fluctuation, resulting in unstable temperature of the high-temperature flue gas entering the drying tower, and further making the evaporation effect of the drying tower on the wastewater extremely unstable.

[0003] In order to judge the evaporation effect of the drying tower on the wastewater, currently only two methods of sampling detection and empirical judgment can be used; among them, sampling detection needs to extract ash samples from the outlet of the ash discharge pipeline of the drying tower, and after extraction, the ash moisture content is calculated by drying for several hours. This method is time-consuming and cannot quickly reflect the wastewater evaporation effect; empirical judgment indirectly reflects the wastewater evaporation effect through the temperature of the flue gas at the outlet of the drying tower. This method is mainly based on operation experience and has uncertainty, so the reliability is not high. The above sampling detection and empirical judgment cannot quickly and accurately reflect the evaporation effect of the wastewater, and thus cannot provide a necessary basis for the reasonable adjustment of the operation parameters of the wastewater drying system. If the wastewater evaporation is poor, it will lead to failures such as wet ash, blockage, and corrosion, thus having a serious adverse impact on the normal operation of the system.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a zero-emission method for wastewater that can be continuously monitored and intelligently adjusted, which can detect the moisture content of flue gas ash in real time and timely and reasonably adjust the operation parameters of the atomization drying equipment, which is beneficial to reducing equipment energy consumption and ensuring the stable operation of the equipment.

[0006] The zero-emission method for wastewater that can be continuously monitored and intelligently adjusted of the present invention includes the following steps:

[0007] S1: Feed the wastewater into the atomizer of the atomization drying equipment to be atomized into droplets according to a preset gas-liquid ratio, and at the same time feed the high-temperature flue gas into the atomization drying equipment;

[0008] S2: Take real-time samples and weigh the ash in the flue gas before entering the atomization drying equipment and after flowing out of the atomization drying equipment, and calculate the ash moisture content X of the flue gas after flowing out of the atomization drying equipment through the following formula:

[0009] X = (m2 - m1) / m2

[0010] Wherein, m1 is the mass of the flue gas ash sample before entering the atomization drying equipment, and m2 is the mass of the flue gas ash sample after flowing out of the atomization drying equipment; m1 and m2 are the results of the ash mass detection at the same time;

[0011] S3: Adjust the gas-liquid ratio of the atomization drying equipment according to the ash moisture content X.

[0012] In step S1, the temperature T of the flue gas (i.e., high-temperature flue gas) before entering the atomization drying equipment should be 280 - 400 °C; the atomization drying equipment operates at a preset gas-liquid ratio first, and the preset gas-liquid ratio is set in the following way:

[0013] If 280 °C ≤ T ≤ 320 °C, set the preset gas-liquid ratio to 15500 - 16500 Nm 3 / m 3 ;

[0014] If 320 °C < T ≤ 360 °C, set the preset gas-liquid ratio to 12000 - 14500 Nm 3 / m 3 ;

[0015] If 360 °C < T ≤ 400 °C, set the preset gas-liquid ratio to 10000 - 11000 Nm 3 / m 3 .

[0016] In step S3, during the operation of the atomization drying equipment, adjust the gas-liquid ratio of the atomization drying equipment according to the ash moisture content X, and the adjustment method is as follows:

[0017] If X ≤ 1.0%, reduce the gas-liquid ratio by 5 - 15%; if 1.0% < X ≤ 2.0%, keep the preset gas-liquid ratio unchanged; if 2.0% < X ≤ 3.0%, increase the gas-liquid ratio by 5 - 15%; if 3.0% < X ≤ 4.0%, increase the gas-liquid ratio by 16 - 24%; if 4.0% < X ≤ 5.0%, increase the gas-liquid ratio by 25 - 35%; if X > 5.0%, stop the operation of the atomization drying equipment.

[0018] The above adjustments to the gas-liquid ratio of the atomization drying equipment are all adjusted based on the preset gas-liquid ratio; when adjusting the gas-liquid ratio, adjust the wastewater flow rate first, and then adjust the flue gas flow rate.

[0019] The atomization drying equipment includes a dryer, an atomizer is provided at the top of the dryer, the atomizer is communicated with the wastewater pipeline, a wastewater regulating valve is provided on the wastewater pipeline, an inlet flue and an outlet flue are respectively provided at the upper and lower parts of the dryer, a flue gas regulating valve is provided on the inlet flue, and an ash discharge pipeline is provided at the bottom of the dryer.

[0020] The dryer is mainly used for evaporating and drying wastewater by using high-temperature flue gas. The wastewater enters the dryer after being atomized by the atomizer through the wastewater pipeline, and the wastewater flow rate is adjusted by the wastewater regulating valve; the atomizer is mainly used for atomizing the wastewater into droplets; the atomizer can adopt a centrifugal atomizer or a multi-fluid atomizer, and the average particle size of the droplets is 30-100 μm. The high-temperature flue gas enters the dryer through the inlet flue, and the flue gas flow rate is adjusted by the flue gas regulating valve. The high-temperature flue gas and the droplets formed by the atomization of the wastewater are in full contact and heat exchange inside the dryer, and the heat of the high-temperature flue gas is used to evaporate and dry the wastewater droplets. The wastewater droplets are dried into solid particulate matter (i.e., ash) and discharged through the ash discharge pipeline.

[0021] Detection devices for real-time sampling and weighing of the ash in the flue gas before entering the atomization drying equipment and after flowing out of the atomization drying equipment are respectively arranged in parallel on the inlet flue and the outlet flue. The detection devices of the inlet flue and the outlet flue have the same structure.

[0022] Specifically, the detection device includes a flue gas inlet pipe, a flue gas transmission pipe and an ash transmission pipe. A valve and a filter are successively arranged on the flue gas inlet pipe. The flue gas outlet and the ash outlet of the filter are respectively communicated with the flue gas transmission pipe and the ash transmission pipe. A fan is arranged on the flue gas transmission pipe. An ash meter for real-time detection of the ash mass and an ash transmission pump for conveying the ash are arranged at the outlet end of the ash transmission pipe.

[0023] The filter is mainly used for intercepting the ash in the flue gas, and the aperture of the filter can be 20-30 μm. The fan is mainly used for providing the conveying power for the high-temperature flue gas, so that the high-temperature flue gas flows from the flue gas inlet pipe through the filter to the flue gas transmission pipe. The ash meter is mainly used for detecting the ash mass; the ash meter includes a weight sensor for weighing the ash with a rated volume in the ash transmission pipe; it can be understood that the sizes of the ash transmission pipes and the weight sensors of the detection devices on the inlet flue and the outlet flue can be exactly the same, and at this time the ash volumes flowing through the weight sensor are the same.

[0024] Furthermore, a constant-volume device can be arranged above the weight sensor. The constant-volume device has openings at both ends and is in the shape of a hollow cylinder. The ash conveying pipe is in an L shape. The constant-volume device is horizontally arranged in the horizontal section of the ash conveying pipe. The constant-volume devices of the detection devices on the inlet flue and the outlet flue have the same diameter and volume. The ash in the ash conveying pipe is shunted through the constant-volume device for constant volume and weighed by the weight sensor located below the constant-volume device. At this time, the constant-volume device weighs the ash of the same volume, further ensuring the accuracy of the measurement result. The volume of the constant-volume device can be 2.5 - 5L.

[0025] In addition, a first pressure gauge is arranged on the smoke inlet pipe at the inlet end of the filter, and a second pressure gauge and a soot blower are arranged on the smoke outlet pipe at the outlet end of the filter; when the pressure value of the second pressure gauge drops to 50 - 60% of the pressure value of the first pressure gauge, the soot blower is started to blow soot on the filter.

[0026] Furthermore, a reducer pipe is arranged between the smoke inlet pipe and the ash conveying pipe. The reducer pipe is used to further compact the ash; a one-way exhaust filter element is arranged at the connection between the reducer pipe and the ash conveying pipe. The one-way exhaust filter element is used to discharge the trace residual gas in the ash outward during the ash compaction process, and at the same time, external gas cannot enter the filter element inward; the diameter of the ash conveying pipe is 1 / 4 to 1 / 2 of the diameter of the smoke inlet pipe.

[0027] The atomization drying device further includes a controller. The controller is provided with a calculation module for calculating the moisture content X of the ash. The calculation module is electrically connected to the ash meter. The controller adjusts the gas-liquid ratio of the atomization drying device according to the moisture content X of the ash.

[0028] The implementation of the present invention has at least the following advantages:

[0029] 1) The zero wastewater discharge method of the present invention can perform real-time online monitoring of the moisture content of the ash, without the need for offline drying treatment for several hours, greatly shortening the detection time and realizing the instant monitoring of the wastewater evaporation effect.

[0030] 2) The zero wastewater discharge method of the present invention can directly detect the moisture content of the flue gas ash at the outlet of the atomization drying device, which can accurately reflect the wastewater evaporation and drying effect of the device, avoiding empirical inference through indicators such as temperature and reducing the operation risk of the atomization drying device.

[0031] 3) The zero wastewater discharge method of the present invention can adjust the operation parameters of the atomization drying device in real time based on the online monitoring results, improving the wastewater evaporation effect, ensuring the stability of the operation of the atomization drying device, and at the same time being beneficial to reducing the energy consumption of the device. Description of the Drawings

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 Structural schematic diagram of a wastewater zero - discharge device in an embodiment;

[0034] Figure 2 Structural schematic diagram of a detection device in an embodiment.

[0035] Explanation of reference numerals:

[0036] 1: Dryer; 2: Atomizer; 3: Wastewater pipeline; 31: Wastewater regulating valve; 4: Inlet flue; 41: Flue gas regulating valve; 5: Outlet flue; 6: First detection device; 7: Second detection device; 8: Ash discharge pipeline; 9: Smoke inlet pipe; 10: Valve; 11: Filter; 12: Smoke transmission pipe; 13: Ash transmission pipe; 14: Fan; 15: Ash meter; 16: Ash transfer pump; 17: Reducing pipe; 18: First pressure gauge; 19: Second pressure gauge; 20: Soot blower; 21: Unidirectional exhaust filter element. Specific embodiments

[0037] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] The following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0040] Embodiment 1

[0041] The method for continuous monitoring and intelligent regulation of zero wastewater discharge in this embodiment includes the following steps:

[0042] S1: Feed the wastewater into the atomizer of the atomizing drying equipment to atomize it into droplets according to a preset gas-liquid ratio, and at the same time feed the high-temperature flue gas into the atomizing drying equipment;

[0043] S2: Take real-time samples and weigh the ash in the flue gas before entering the atomizing drying equipment and after flowing out of the atomizing drying equipment respectively, and calculate the ash moisture content X of the flue gas after flowing out of the atomizing drying equipment through the following formula:

[0044] X = (m2 - m1) / m2

[0045] where m1 is the mass of the flue gas ash sample before entering the atomizing drying equipment, and m2 is the mass of the flue gas ash sample after flowing out of the atomizing drying equipment;

[0046] S3: Adjust the gas-liquid ratio of the atomizing drying equipment according to the ash moisture content X.

[0047] The temperature T of the flue gas (i.e., high-temperature flue gas) before entering the atomizing drying equipment should be 280 - 400 °C; the atomizing drying equipment operates at a preset gas-liquid ratio first, and the preset gas-liquid ratio is set in the following way:

[0048] If 280 °C ≤ T ≤ 320 °C, set the preset gas-liquid ratio to 15500 - 16500 Nm 3 / m 3 ;

[0049] If 320 °C < T ≤ 360 °C, set the preset gas-liquid ratio to 12000 - 14500 Nm 3 / m 3 ;

[0050] If 360 °C < T ≤ 400 °C, set the preset gas-liquid ratio to 10000 - 11000 Nm 3 / m 3 。

[0051] During the operation of the atomizing drying equipment, adjust the gas-liquid ratio of the atomizing drying equipment according to the ash moisture content X, and the adjustment method is as follows:

[0052] If X ≤ 1.0%, reduce the gas-liquid ratio by 5 - 15%; if 1.0% < X ≤ 2.0%, keep the preset gas-liquid ratio unchanged; if 2.0% < X ≤ 3.0%, increase the gas-liquid ratio by 5 - 15%; if 3.0% < X ≤ 4.0%, increase the gas-liquid ratio by 16 - 24%; if 4.0% < X ≤ 5.0%, increase the gas-liquid ratio by 25 - 35%; if X > 5.0%, stop the operation of the atomizing drying equipment.

[0053] The method for zero wastewater discharge with continuous monitoring and intelligent regulation in this embodiment is carried out by using an atomization drying device; as Figure 1 shown, the atomization drying device includes a dryer 1, the diameter of the dryer 1 can be 2 - 12 m, and the height of the dryer 1 can be 20 - 25 m; an atomizer 2 is provided at the top of the dryer 1, the atomizer 2 is a centrifugal atomizer or a multi-fluid atomizer, and the atomizer 2 is used to atomize the wastewater into droplets with an average particle size of 30 - 100 μm. The atomizer 2 is connected to a wastewater pipe 3, and a wastewater regulating valve 31 for regulating the wastewater flow rate is provided on the wastewater pipe 3. An inlet flue 4 and an outlet flue 5 are respectively provided in the upper and lower parts of the dryer 1, a flue gas regulating valve 41 for regulating the flue gas flow rate is provided on the inlet flue 4, and an ash discharge pipe 8 is provided at the bottom of the dryer 1.

[0054] The high-temperature flue gas enters the dryer through the inlet flue 4, and the flue gas flow rate is regulated by the flue gas regulating valve 41; at the same time, the wastewater is atomized into droplets by the atomizer 2, and the high-temperature flue gas and the droplets formed by the atomization of the wastewater come into full contact and exchange heat inside the dryer 1. The heat of the high-temperature flue gas evaporates and dries the wastewater droplets, and after the wastewater droplets are dried into solid particulate matter (i.e., ash), they are discharged through the ash discharge pipe 8.

[0055] A first detection device 6 for real-time sampling and weighing of the ash in the flue gas before entering the atomization drying device is provided in parallel on the inlet flue 4, and a second detection device 7 for real-time sampling and weighing of the ash in the flue gas after flowing out of the atomization drying device is provided in parallel on the outlet flue 5. The first detection device 6 and the second detection device 7 have the same structure and are collectively referred to as the detection device.

[0056] Combined with Figure 2 shown, the detection device includes a flue gas inlet pipe 9, a flue gas transmission pipe 12 and an ash transmission pipe 13. A valve 10 and a filter 11 are successively provided on the flue gas inlet pipe 9. The filter 11 is mainly used to intercept the ash in the high-temperature flue gas, the pore size of the filter 11 is 20 - 30 μm, the flue gas outlet and the ash outlet of the filter 11 are respectively connected to the flue gas transmission pipe 12 and the ash transmission pipe 13. A fan 14 is provided on the flue gas transmission pipe 12. A reducing pipe 17 is provided between the flue gas inlet pipe 9 and the ash transmission pipe 13, and the reducing pipe 17 can further compact the ash. A one-way exhaust filter element 21 is provided at the connection between the reducing pipe 17 and the ash transmission pipe 13. The one-way exhaust filter element 21 can discharge the trace residual gas in the ash outward during the ash compaction process, and at the same time, external gas cannot enter the filter element inward. The outlet end of the one-way exhaust filter element 21 can be connected to the flue gas transmission pipe 12.

[0057] At the outlet end of the ash conveying pipe 13, there are successively an ash meter 15 for real-time detection of the ash quality and an ash conveying pump 16 for ash conveying. The ash meter 15 includes a weight sensor for weighing the ash with a rated volume in the ash conveying pipe 13. The ash conveying pipe 13 of the detection devices on the inlet flue 4 and the outlet flue 5 and the weight sensor have the same size, and at this time, the ash volume flowing through the weight sensor is the same.

[0058] Further, a constant volume device is arranged above the weight sensor. The constant volume device has openings at both ends and is in a hollow cylindrical shape. The ash conveying pipe 13 is in an L shape, and the constant volume device is horizontally arranged in the horizontal section of the ash conveying pipe 13. The constant volume devices on the detection devices of the inlet flue 4 and the outlet flue 5 have the same diameter and volume. The ash in the ash conveying pipe 13 passes through the constant volume device for constant volume and is weighed by the weight sensor located below the constant volume device. At this time, the constant volume device weighs the ash with the same volume, further ensuring the accuracy of the measurement result. The volume of the constant volume device can be 2.5 - 5L. The ash conveying pump 16 provides power for ash conveying to ensure that the ash is discharged at a stable speed, and the outlet end of the ash conveying pipe 13 can be connected to the ash discharge pipe 8.

[0059] In addition, a first pressure gauge 18 is provided on the smoke inlet pipe 9 at the inlet end of the filter 11, and a second pressure gauge 19 and a soot blower 20 are provided on the smoke outlet pipe 12 at the outlet end of the filter 11; when the pressure value of the second pressure gauge 19 drops to 50 - 60% of the pressure value of the first pressure gauge 18, the soot blower 20 is started to blow the filter 11 to clean the ash blocking the filter 11.

[0060] The atomization drying device further includes a controller. The controller is provided with a calculation module for calculating the ash moisture content X according to the formula X = (m2 - m1) / m2. The calculation module is electrically connected to the ash meter 15. The controller adjusts the gas-liquid ratio of the atomization drying device in real time as follows according to the ash moisture content X:

[0061] If X ≤ 1.0%, the controller adjusts the flue gas regulating valve 41 and / or the waste water regulating valve 31 to reduce the gas-liquid ratio by 5 - 15% relative to the preset gas-liquid ratio; X ≤ 1.0% indicates that the waste water evaporation effect is good, but there is a problem of excessive heat consumption. By reducing the gas-liquid ratio by 5 - 15%, the energy consumption can be reduced by 5 - 15%.

[0062] If 1.0% < X ≤ 2.0%, the controller does not adjust the flue gas regulating valve 41 and the waste water regulating valve 31 to maintain the preset gas-liquid ratio; 1.0% < X ≤ 2.0% indicates that the waste water evaporation effect is good. At this time, the ash moisture content meets the industry standard requirements, has good fluidity, and will not cause equipment operation failures, so there is no need to adjust the operation parameters of the equipment.

[0063] If 2.0% < X ≤ 3.0%, the controller adjusts the flue gas regulating valve 41 and / or the wastewater regulating valve 31 to increase the gas-liquid ratio by 5 - 15% relative to the preset gas-liquid ratio; 2.0% < X ≤ 3.0% indicates that the wastewater evaporation effect is not ideal. At this time, the ash moisture content is slightly higher than the industry standard requirement, but the ash fluidity is still good. Long-term operation will cause equipment operation failures. By increasing the gas-liquid ratio of the equipment by 5 - 15%, the drying capacity of the equipment can be improved and the operation effect of the equipment can be stabilized.

[0064] If 3.0% < X ≤ 4.0%, the controller adjusts the flue gas regulating valve 41 and / or the wastewater regulating valve 31 to increase the gas-liquid ratio by 16 - 24% relative to the preset gas-liquid ratio; 3.0% < X ≤ 4.0% indicates that the wastewater evaporation effect is poor. At this time, the ash moisture content is higher than the industry standard requirement, the ash fluidity becomes poor, and the risk of equipment operation failures is relatively high. By increasing the gas-liquid ratio of the equipment by 16 - 24%, the drying capacity of the equipment can be improved and the operation effect of the equipment can be stabilized.

[0065] If 4.0% < X ≤ 5.0%, the controller adjusts the flue gas regulating valve 41 and / or the wastewater regulating valve 31 to increase the gas-liquid ratio by 25 - 35% relative to the preset gas-liquid ratio; 4.0% < X ≤ 5.0% indicates that the wastewater evaporation effect is poor. At this time, the ash moisture content is higher than the industry standard requirement, the ash fluidity is poor, and it is easy to cause equipment operation failures. By increasing the gas-liquid ratio of the equipment by 25 - 35%, the drying capacity of the equipment can be improved and the operation effect of the equipment can be stabilized.

[0066] If X > 5.0%, the controller closes the flue gas regulating valve 41 and the wastewater regulating valve 31 to stop the operation of the atomizing drying equipment; X > 5.0% indicates that the wastewater evaporation effect is extremely poor, there are risks such as wet ash, blockage, and corrosion, which will cause serious equipment operation failures. At this time, the equipment should stop running.

[0067] Example 2

[0068] The zero-wastewater discharge method of this example is carried out by using the method of Example 1; among them, the diameter of the dryer 1 is 12m and the height is 25m; the atomizer 2 adopts a centrifugal atomizer 2, the average particle size of the droplets formed by the atomization of the wastewater is 30μm, and the pore size of the filter 11 is 20μm; the flue gas temperature before entering the atomizing drying equipment is 280°C, and the preset gas-liquid ratio is 16500 Nm 3 / m 3 。

[0069] After the atomizing drying equipment starts to operate, the controller adjusts the gas-liquid ratio in real time according to the ash moisture content X fed back by the calculation module:

[0070] If X ≤ 1.0%, reduce the gas-liquid ratio by 15%; if 1.0% < X ≤ 2.0%, maintain the preset gas-liquid ratio unchanged; if 2.0% < X ≤ 3.0%, increase the gas-liquid ratio by 15%; if 3.0% < X ≤ 4.0%, increase the gas-liquid ratio by 24%; if 4.0% < X ≤ 5.0%, increase the gas-liquid ratio by 35%; if X > 5.0%, stop the operation of the atomization drying equipment.

[0071] The ash moisture content X of the atomization drying equipment every 7 days of operation, as well as the average energy consumption and operation effect during the operation of the atomization drying equipment, are shown in Table 1; where: the average energy consumption refers to the additional energy that needs to be supplemented to the thermal power unit due to the evaporation and drying of wastewater, which is the average value during the test period.

[0072] Example 3

[0073] The zero-wastewater-discharge method of this example is carried out by using the method of Example 1; among them, the diameter of the dryer 11 is 2 m and the height is 20 m; the atomizer 22 uses a two-fluid atomizer 22, and the average particle size of the droplets formed by the atomization of the wastewater is 100 μm; the flue gas temperature before entering the atomization drying equipment is 400 °C, and the preset gas-liquid ratio is 10500 Nm 3 / m 3 .

[0074] After the atomization drying equipment starts to operate, the controller adjusts the gas-liquid ratio in real time according to the ash moisture content X fed back by the calculation module:

[0075] If X ≤ 1.0%, reduce the gas-liquid ratio by 5%; if 1.0% < X ≤ 2.0%, maintain the preset gas-liquid ratio unchanged; if 2.0% < X ≤ 3.0%, increase the gas-liquid ratio by 5%; if 3.0% < X ≤ 4.0%, increase the gas-liquid ratio by 16%; if 4.0% < X ≤ 5.0%, increase the gas-liquid ratio by 25%; if X > 5.0%, stop the operation of the atomization drying equipment.

[0076] The ash moisture content X of the atomization drying equipment every 7 days of operation, as well as the average energy consumption and operation effect during the operation of the atomization drying equipment, are shown in Table 2.

[0077] Control Example 1

[0078] Except that the controller is not used to adjust the gas-liquid ratio of the atomization drying equipment, and the gas-liquid ratio of the atomization drying equipment is fixedly set to 16500 Nm 3 / m 3 otherwise, the rest is basically the same as in Example 2.

[0079] The ash moisture content X of the atomization drying equipment every 7 days of operation, as well as the average energy consumption and operation effect during the operation of the atomization drying equipment, are shown in Table 1.

[0080] Table 1 Ash moisture content, average energy consumption and operation effect of Example 2 and Control Example 1

[0081]

[0082] Comparative Example 2

[0083] Except that the controller is not used to adjust the gas-liquid ratio of the atomization drying equipment, and the gas-liquid ratio of the dryer is fixedly set to 10500 Nm 3 / m 3 otherwise, it is basically the same as Example 3.

[0084] The ash moisture content X of the atomization drying equipment every 7 days of operation, as well as the average energy consumption and operation effect during the operation of the atomization drying equipment, are shown in Table 2.

[0085] Comparative Example 3

[0086] Except that the real-time adjustment method of the gas-liquid ratio of the atomization drying equipment by the controller is different, otherwise, it is basically the same as Example 3.

[0087] The real-time adjustment method of the gas-liquid ratio of the atomization drying equipment by the controller in this comparative example is as follows:

[0088] If X ≤ 2.0%, keep the preset gas-liquid ratio unchanged; if 2.0% < X ≤ 4.0%, increase the gas-liquid ratio by 10%; if 4.0% < X ≤ 5.0%, increase the gas-liquid ratio by 20%; if X > 5.0%, the atomization drying equipment stops running.

[0089] The ash moisture content X of the atomization drying equipment every 7 days of operation, as well as the average energy consumption and operation effect during the operation of the atomization drying equipment, are shown in Table 2.

[0090] Table 2 Ash moisture content, average energy consumption and operation effect of Example 3 and Comparative Examples 2 and 3

[0091]

[0092] The above results show that:

[0093] 1. Comparative Examples 1 and 2 do not adjust the gas-liquid ratio of the atomization drying equipment, resulting in unstable drying effect of the wastewater and being unable to well cope with the adverse effects brought by the temperature fluctuation of the high-temperature flue gas. When the ash moisture content X ≤ 1.0%, it will cause waste of heat energy and lead to a significant increase in the energy consumption of the atomization drying equipment; when the ash moisture content X > 2.0%, there will be failures such as wet ash and blockage, and some ash will agglomerate and cake, thus affecting the recovery and utilization of the ash.

[0094] 2. In Comparative Example 3, other methods were used to adjust the gas-liquid ratio of the atomization drying equipment, but the ash moisture content could not be stably controlled within 1-2%. This not only failed to meet the requirements of industry standards but also led to problems such as wet ash, blockage, and corrosion, affecting the recycling and utilization of ash and being unfavorable to the stable operation of the atomization drying equipment.

[0095] 4. The methods of Examples 2-3 can stably maintain the ash moisture content at the outlet of the atomization drying equipment within 1-2%, well overcoming the adverse effects caused by the temperature fluctuations of high-temperature flue gas. It can not only meet the requirements of industry standards but also reduce the energy consumption of the atomization drying equipment, improving both the wastewater evaporation effect of the atomization drying equipment and ensuring its safe and stable operation.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for zero discharge of wastewater with continuous monitoring and intelligent regulation, characterized in that, It includes the following steps: S1: Feed the wastewater into the atomizer of the atomizing dryer according to a preset gas-liquid ratio to atomize it into droplets, and at the same time feed the high-temperature flue gas into the atomizing dryer; S2: Take real-time samples and weigh the ash in the flue gas before entering the atomizing dryer and after flowing out of the atomizing dryer respectively, and calculate the ash moisture content X of the flue gas after flowing out of the atomizing dryer through the following formula: X = (m2 - m1) / m2 where m1 is the mass of the flue gas ash sample before entering the atomizing dryer, and m2 is the mass of the flue gas ash sample after flowing out of the atomizing dryer; S3: Adjust the gas-liquid ratio of the atomizing dryer according to the ash moisture content X; The atomizing dryer includes a dryer, an atomizer is provided at the top of the dryer, the atomizer is connected to the wastewater pipeline, a wastewater regulating valve is provided on the wastewater pipeline, an inlet flue and an outlet flue are respectively provided at the upper and lower parts of the dryer, a flue gas regulating valve is provided on the inlet flue, a dust discharge pipeline is provided at the bottom of the dryer, and detection devices for taking real-time samples and weighing the ash in the flue gas before entering the atomizing dryer and after flowing out of the atomizing dryer are respectively connected in parallel on the inlet flue and the outlet flue; The detection device includes a flue gas inlet pipe, a flue gas transmission pipe and a dust transmission pipe. A valve and a filter are successively provided on the flue gas inlet pipe. The flue gas outlet and the ash outlet of the filter are respectively connected to the flue gas transmission pipe and the dust transmission pipe. A fan is provided on the flue gas transmission pipe. At the outlet end of the dust transmission pipe, a dust counter for real-time detection of the ash mass and a dust conveying pump for conveying the ash are successively provided. The dust counter includes a weight sensor for weighing the ash with a rated volume in the dust transmission pipe. The dust transmission pipes and the weight sensors of the detection devices on the inlet flue and the outlet flue have exactly the same dimensions, and at this time the ash volume flowing through the weight sensor is the same; The gas-liquid ratio of the atomizing dryer is adjusted in the following way: If X ≤ 1.0%, reduce the gas-liquid ratio by 5 - 15%; if 1.0% < X ≤ 2.0%, keep the preset gas-liquid ratio unchanged; if 2.0% < X ≤ 3.0%, increase the gas-liquid ratio by 5 - 15%; if 3.0% < X ≤ 4.0%, increase the gas-liquid ratio by 16 - 24%; if 4.0% < X ≤ 5.0%, increase the gas-liquid ratio by 25 - 35%; if X > 5.0%, the atomizing dryer stops operating.

2. The zero liquid discharge method for wastewater according to claim 1, wherein The temperature T of the flue gas before entering the atomizing dryer is 280 - 400 °C; the preset gas-liquid ratio is set in the following way: If 280 °C ≤ T ≤ 320 °C, set the preset gas-liquid ratio to 15500 - 16500 Nm 3 / m 3 ; If 320 °C < T ≤ 360 °C, set the preset gas-liquid ratio to 12000 - 14500 Nm 3 / m 3 ; If 360 °C < T ≤ 400 °C, set the preset gas-liquid ratio to 10000 - 11000 Nm 3 / m 3 .

3. The zero wastewater discharge method according to claim 1, characterized in that The atomizer is a centrifugal atomizer or a multi-fluid atomizer; the average particle size of the droplets is 30 - 100 μm.

4. The zero wastewater discharge method according to claim 1, characterized in that, A first pressure gauge is provided on the flue gas inlet pipe at the inlet end of the filter, and a second pressure gauge and a soot blower are provided on the flue gas transmission pipe at the outlet end of the filter; when the pressure value of the second pressure gauge drops to 50 - 60% of the pressure value of the first pressure gauge, start the soot blower to blow the filter.

5. The zero - discharge method for wastewater according to claim 1, wherein A reducer is provided between the flue gas inlet pipe and the dust transmission pipe, and a one-way exhaust filter element is provided at the connection between the reducer and the dust transmission pipe.

6. The zero liquid discharge method for wastewater according to claim 1, wherein The atomization drying equipment further includes a controller, and the controller is provided with a calculation module for calculating the moisture content X of the ash. The calculation module is electrically connected to the ash meter, and the controller adjusts the gas-liquid ratio of the atomization drying equipment according to the moisture content X of the ash.

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