Intelligent collaborative treatment system for cement kiln desulfurization wastewater

Abstract

The application discloses a cement kiln desulfurization wastewater intelligent collaborative treatment system, and belongs to the technical field of cement kiln flue gas wet desulfurization wastewater treatment. The system comprises an electric control valve, a cyclone, a vacuum dewatering machine, a filter cake moisture content detector, a wastewater adjusting tank, a multi-parameter water quality detector, a neutralization reaction flocculation device, a dosing pump, a precipitation device, a water quality detector, a reused water tank, a water supply pump, a dust concentration detector, a temperature sensor and an intelligent control module. The intelligent control module can adjust the water demand on demand, predict the water demand and reversely adjust the wastewater treatment rate. Meanwhile, the dehydration time and the feed valve opening degree are linked and adjusted in combination with the operation condition of the desulfurization tower and the filter cake moisture content. The dosing amount is closed-loop adjusted according to the water quality in and out, and the filter cake target moisture content, the dosing coefficient and the water tank liquid level and other parameters are collaboratively optimized, so that the full-automatic operation of reverse adjustment from the water demand end is realized, the comprehensive operation cost is reduced, and the wastewater zero discharge problem is solved.

Description

Technical Field

[0001] This invention relates to the field of wet desulfurization wastewater treatment technology for cement kiln flue gas, and particularly to an intelligent collaborative treatment system for cement kiln desulfurization wastewater. Background Technology

[0002] Limestone-gypsum wet desulfurization is the mainstream desulfurization technology in the cement industry. The byproducts are desulfurization gypsum and desulfurization wastewater. Currently, the cement industry generally sprays untreated desulfurization wastewater directly into the grate cooler (about 190°C) for evaporation, which can easily lead to problems such as caking on the duct walls, equipment corrosion, and affecting the quality of clinker. This method has failed to achieve stable zero discharge of desulfurization wastewater.

[0003] Unlike the power industry, cement kiln flue gas has a lower sulfur content (for example, a 5000t / d cement kiln typically produces approximately 550,000 Nm³ of flue gas at the kiln tail). 3 / h, SO2 concentration ≤2000mg / Nm 3 The gypsum dewatering workshop operates at a low frequency and generates a small amount of desulfurization wastewater (typically 0~3m³). 3 / h). Cement kilns have production processes such as spray dust suppression and mill spraying, and can use treated desulfurization wastewater. The water demand is roughly equivalent to the volume of desulfurization wastewater; moreover, the water quality requirements are relatively lower than those for domestic water and conventional industrial water. This characteristic provides a feasible premise for adapting wastewater treatment systems to cement kilns. However, existing wastewater treatment technologies have the following problems in the application of cement kilns: (1) The water demand for dust suppression spraying and mill spraying is characterized by high intermittency and strong fluctuations, because the use of these two methods depends on the dust concentration in the stockpile and the temperature inside the mill. The water demand flow rate can jump from zero to the maximum value within a few minutes. Conventional continuous control logic cannot accurately respond to such demand fluctuations, resulting in excessive water spraying or insufficient water volume. If the water production capacity design and the equalization tank and reclaimed water tank are not matched, it will cause investment waste and accumulation of sediment in the tank. (2) Vacuum dewatering machines and gypsum slurry discharge pumps are mostly operated at a fixed speed. The moisture content of the filter cake is unstable (too wet affects use, too dry increases energy consumption). The output of filtrate and the subsequent water demand are difficult to match, and overflow of the equalization tank or the recycled water tank or empty pump operation often occurs. (3) Cement enterprises generally do not have dedicated water treatment personnel, and the control system must be highly adaptive and low-maintenance; (4) The three stages of dehydration, wastewater treatment and water demand are independent of each other and lack coordinated control and optimization, resulting in high overall operating costs. For example, the dehydration stage consumes excessive electricity in order to pursue low water content, and the dosing stage overdoses chemicals in order to control inaccurately.

[0004] In summary, how to completely achieve zero discharge of desulfurization wastewater and establish a fully automated intelligent treatment system that adjusts from the demand side in reverse and achieves coordinated optimization of dewatering, wastewater treatment, and water demand is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] (a) Technical problems to be solved This invention provides an intelligent collaborative treatment system for desulfurization wastewater from cement kilns, aiming to replace the direct injection method of grate coolers. It utilizes the characteristics of cement kiln wet desulfurization systems, namely "small wastewater volume, multiple water demand points, and low water quality requirements," to solve problems such as waste of pool capacity, unstable filter cake moisture content, delayed water supply response, and lack of coordination among various links in existing technologies. It achieves fully automatic and low-cost operation by reverse adjustment from the water demand side.

[0006] (II) Technical Solution This invention provides an intelligent co-treatment system for desulfurization wastewater from cement kilns, comprising: an electric control valve, a hydrocyclone, a vacuum dewatering machine, a filter cake moisture content detector, a wastewater equalization tank, a multi-parameter water quality analyzer, a neutralization reaction flocculation device, a dosing pump, a sedimentation device, a water quality analyzer, a recycled water tank, a water supply pump, a dust concentration detector, a temperature sensor, and an intelligent control module. The electric control valve is installed at the inlet of the hydrocyclone, and the outlet of the hydrocyclone is connected to the feed inlet of the vacuum dewatering machine. The filter cake moisture content detector is installed at the discharge outlet of the vacuum dewatering machine, and the wastewater equalization tank... The inlet of the wastewater regulating tank is connected to the filtrate outlet of the vacuum dewatering machine. The multi-parameter water quality analyzer is installed at the outlet of the wastewater regulating tank, and the inlet of the neutralization reaction flocculation device is connected to the outlet of the wastewater regulating tank. The dosing pump is located at the dosing port of the neutralization reaction flocculation device, and the inlet of the sedimentation device is connected to the outlet of the neutralization reaction flocculation device. The water quality analyzer is installed at the outlet of the sedimentation device, and the inlet of the recycled water tank is connected to the supernatant outlet of the sedimentation device. The inlet of the water supply pump is connected to the outlet of the recycled water tank, and its outlet is connected to the spray gun at each water usage point.

[0007] Furthermore, no membrane separation device or evaporation crystallization device is installed between the neutralization reaction flocculation device and the precipitation device.

[0008] As a further embodiment of the present invention, the design capacity of the wastewater equalization tank and the recycled water tank is determined according to the average water demand.

[0009] Furthermore, the dust concentration detector is installed at the dust suppression spray point in the raw material storage yard, the temperature sensor is installed inside the mill, and the intelligent control module is connected to the above-mentioned equipment and instruments.

[0010] As a further embodiment of the present invention, the vacuum dehydrator is driven by a variable frequency motor, and its filter cake outlet falls directly into the gypsum silo.

[0011] Furthermore, the neutralization reaction flocculation device integrates a neutralization zone, a reaction zone, and a flocculation zone. Each zone is fed with lime powder, PAC, PAM, and organic sulfur materials by a dosing pump. The sedimentation device adopts a conical settling device, and the sediment is discharged through the sedimentation port at the bottom cone end.

[0012] This invention also provides a method for the intelligent co-treatment of desulfurization wastewater from cement kilns, comprising the following steps: S1: Water demand acquisition and adjustment: Real-time acquisition of dust concentration and equipment temperature signals. When the dust concentration or equipment temperature is higher than the set value, it is determined that there is a water demand. The required water demand is calculated based on the signal feedback value and adjusted in real time. When the dust concentration or temperature meets the emission and safety indicators, the water demand is gradually reduced until dynamic balance is achieved. S2: Predict water demand and adjust wastewater volume: Based on the changing pattern of water demand, predict the water demand in the future period and adjust the treatment rate of the neutralization reaction flocculation device in advance so that the wastewater treatment capacity of the system always follows the actual water demand. S3: Dehydration and water demand balance control: Receives the signal from the filter cake moisture content detector, and adjusts the dehydration time of the vacuum dehydrator and the opening of the electric regulating valve according to the preset target moisture content of the filter cake, the liquid level of the recycled water tank, the water demand, and the operating conditions of the pH value, liquid level and slurry density in the desulfurization tower. At the same time, it dynamically matches the water supply of the gypsum slurry discharge pump. S4: Acquisition and adjustment of dosing amount: Receives signals from multi-parameter water quality analyzer and water quality analyzer, calculates the required dosage of chemicals according to the preset effluent water quality requirements and adjusts it in real time. When the effluent water quality meets the reuse requirements, the dosage of chemicals is gradually reduced to dynamic equilibrium. S5: Dehydration-Wastewater Treatment-Water Demand Co-optimization: Taking the synergy and operating cost of the above S1-S4 steps as the objective, the target moisture content of the filter cake, the quality of the effluent, the level of the recycled water tank, the predicted water demand, and the pH value, level and slurry density in the desulfurization tower are used as joint optimization variables, and the optimization algorithm is used for global adjustment.

[0013] Furthermore, the intelligent control module is also configured to: in the collaborative optimization of S5, when the demand for recycled water increases, automatically increase the target moisture content of the filter cake within the allowable range to release the processing capacity of the dewatering unit, while increasing the response speed of the water supply pump; when the demand for recycled water decreases, automatically stabilize the target moisture content of the filter cake and reduce the dosage.

[0014] The beneficial effects of this invention are as follows: 1. Simplified and adaptable process, fully automatic operation: No membrane system or evaporation crystallization is required, and the investment is only 10% to 20% of the deep treatment process in the power industry; all detection, judgment, adjustment and optimization are completed intelligently without human intervention, which is particularly suitable for unattended operation in cement plants, and completely solves the problem of stable zero discharge of desulfurization wastewater in cement plants.

[0015] 2. Demand-driven reverse regulation to eliminate production-consumption disconnect: By utilizing real-time production signals such as dust concentration and equipment temperature, the processing and supply of water can be adjusted from the water demand side, solving the problem of high intermittent fluctuations in water demand at cement kilns.

[0016] 3. Production based on demand, reducing tank volume: Wastewater equalization tanks and reclaimed water tanks are designed according to average water demand. Through accurate demand forecasting and dynamic adjustment, instantaneous peaks can be dealt with, and the reduced tank volume significantly reduces investment costs and the frequency of sediment cleaning.

[0017] 4. Dewatering-water demand linkage to stabilize filter cake moisture content: The filter cake moisture content is stably controlled at 13%~18%, which improves the quality and transport performance of gypsum; at the same time, the dewatering water volume is dynamically matched according to the water demand and tank position to avoid overflow or empty pump.

[0018] 5. Global collaborative optimization to reduce overall costs: The operating costs of the three stages of dehydration, wastewater treatment, and water demand are uniformly incorporated into the objective function, avoiding the overall cost increase caused by local optima in a single stage and reducing the overall operating cost. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure and connection of the system of the present invention; Figure 2 This is a flowchart illustrating the working method of the present invention.

[0020] In the diagram: 1. Electric control valve; 2. Hydrocyclone; 3. Vacuum dewatering machine; 4. Filter cake moisture content meter; 5. Wastewater equalization tank; 6. Multi-parameter water quality meter; 7. Neutralization reaction flocculation device; 8. Dosing pump; 9. Sedimentation device; 10. Water quality meter; 11. Reclaimed water tank; 12. Water supply pump; 13. Dust concentration meter; 14. Temperature sensor; 15. Intelligent control module. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. It should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "arrangement" should be interpreted broadly. For those skilled in the art, the specific meaning of the above terms in this patent can be understood according to the specific circumstances.

[0022] Reference Figures 1-2Taking a 5000t / d cement kiln desulfurization wastewater intelligent co-treatment system as an example, it includes an electric control valve 1 installed on the inlet pipe of a hydrocyclone 2 (electric butterfly valves can be used), with 2-4 units. The underflow port of the hydrocyclone 2 is connected to the feed inlet of a vacuum dewatering machine 3. The vacuum dewatering machine 3 is a frequency conversion belt dewatering machine, and its filter cake outlet faces the gypsum silo, where the filter cake falls directly. The filter cake moisture content detector 4 is a microwave moisture meter, which performs online non-contact measurement and is installed at the discharge port. The filtrate produced by the vacuum dewatering machine 3 flows by gravity through a pipeline to a wastewater equalization tank 5. The vacuum dewatering machine 3 is arranged above the wastewater equalization tank 5, and the wastewater equalization tank 5 is designed with an effective volume of ~60m³ based on the average water demand. 3 The pool is equipped with an aeration and stirring system, located underground. A multi-parameter water quality analyzer (6) is installed on its outlet pipe to measure pH, turbidity, heavy metals, etc., and then connected to a neutralization reaction flocculation device (7). The neutralization reaction flocculation device (7) integrates a neutralization zone, a reaction zone, and a flocculation zone. Each zone is injected with lime powder, PAC, PAM, organic sulfur, etc., by a dosing pump (8). The sedimentation device (9) uses a conical settling tank; the sediment is discharged through the sedimentation port at the bottom of the cone, and the supernatant flows by gravity into a reclaimed water tank (11) with an effective volume of ~60m³. 3 A water quality tester 10 and a turbidity meter are installed at the outlet of the sedimentation device 9. The outlet of the recycled water tank 11 is connected to a water supply pump 12. Multiple pumps are connected in parallel to deliver water to the spray dust suppression point and the mill spray point respectively. A dust concentration tester 13 is installed at the spray dust suppression point. A temperature sensor 14 is installed inside the mill. The intelligent control module 15 is electrically connected to all the above instruments and actuators.

[0023] This invention also proposes a working method for an intelligent collaborative treatment system for desulfurization wastewater from cement kilns, comprising the following steps: S1: Real-time acquisition of dust concentration in the limestone stockpile and equipment temperature signals inside the mill. When the dust concentration exceeds the start-up value, such as >30mg / m³, the system will detect the dust concentration. 3 Or the temperature is higher than the starting value, such as >70mg / m³ 3 When a water demand is detected, the required water consumption is calculated based on the signal strength. When the dust concentration or temperature meets the emission and safety standards, the water consumption is gradually reduced until a dynamic balance is reached. S2: The intelligent control module records the average water supply and trend of the past 5 minutes, predicts the water demand in the next 2 minutes, and adjusts the wastewater treatment rate of the neutralization reaction flocculation device 7 2 minutes in advance, so that the wastewater treatment capacity of the system always follows the actual water demand. S3: The intelligent control module reads the filter cake moisture content and, based on the preset filter cake target (e.g., 15% moisture content), sends a dewatering time adjustment command to the vacuum dewatering machine 3 and an opening adjustment command to the electric regulating valve 1 at the hydrocyclone inlet. When the filter cake moisture content is higher than the target value, the dewatering time is increased and the valve opening is decreased; conversely, the dewatering time is decreased and the valve opening is increased. The intelligent control module matches the target filter cake moisture content and water demand, and sends dynamic adjustment commands to the gypsum slurry discharge pump. S4: The intelligent control module calculates the dosage based on the pH, turbidity, and heavy metals of the influent water according to the model, drives the dosing pump 8, and sends a dosing adjustment command to the dosing pump 8; when the effluent water quality meets the reuse requirements, the dosage is gradually reduced to dynamic equilibrium. S5: Every 8 hours, power consumption, chemical consumption, target moisture content of filter cake, effluent quality, level of recycled water tank, and predicted water demand are collected as joint optimization variables. The optimization algorithm is used to adjust the variables globally, and the optimization results are automatically updated to the settings of S3 and S4.

[0024] The specific settings involved in the above steps (such as dust concentration threshold, temperature threshold, target moisture content range of filter cake, volume, etc.) can be determined by those skilled in the art through conventional tests based on actual working conditions. Examples are given here but not limited to these settings.

Claims

1. A smart collaborative treatment system for desulfurization wastewater from cement kilns, characterized in that, include: Electric control valve (1), hydrocyclone (2), vacuum dewatering machine (3), filter cake moisture content detector (4), wastewater regulating tank (5), multi-parameter water quality detector (6), neutralization reaction flocculation device (7), dosing pump (8), sedimentation device (9), water quality detector (10), recycled water tank (11), water supply pump (12), dust concentration detector (13), temperature sensor (14), intelligent control module (15). The electric control valve (1) is installed at the inlet of the hydrocyclone (2), and the outlet of the hydrocyclone (2) is connected to the feed port of the vacuum dewatering machine (3). The filter cake moisture content detector (4) is installed at the outlet of the vacuum dewatering machine (3), and the wastewater regulating tank (5) is connected to the feed port of the vacuum dewatering machine (3). The inlet of the device is connected to the filtrate outlet of the vacuum dehydrator (3), the multi-parameter water quality analyzer (6) is installed at the outlet of the wastewater regulating tank (5), and the inlet of the neutralization reaction flocculation device (7) is connected to the outlet of the wastewater regulating tank (5). The dosing pump (8) is set at the dosing port of the neutralization reaction flocculation device (7), and the inlet of the sedimentation device (9) is connected to the outlet of the neutralization reaction flocculation device (7). The water quality analyzer (10) is installed at the outlet of the sedimentation device (9), and the inlet of the recycled water tank (11) is connected to the supernatant outlet of the sedimentation device (9). The inlet of the water supply pump (12) is connected to the outlet of the recycled water tank (11), and its outlet is connected to the spray gun at each water point.

2. The intelligent collaborative treatment system for desulfurization wastewater from cement kilns according to claim 1, characterized in that, No membrane separation device or evaporation crystallization device is installed between the neutralization reaction flocculation device (7) and the precipitation device (9).

3. The intelligent collaborative treatment system for desulfurization wastewater from cement kilns according to claim 1, characterized in that, The design capacity of the wastewater regulating tank (5) and the recycled water tank (11) is determined according to the average water demand.

4. The intelligent collaborative treatment system for desulfurization wastewater from cement kilns according to claim 1, characterized in that, The dust concentration detector (13) is installed at the dust suppression spray point in the raw material stockpile, the temperature sensor (14) is installed inside the mill, and the intelligent control module (15) is connected to the above-mentioned equipment and instruments.

5. The intelligent collaborative treatment system for desulfurization wastewater from cement kilns according to claim 1, characterized in that, The vacuum dehydrator (3) is driven by a variable frequency motor, and its filter cake outlet falls directly into the gypsum storage.

6. The intelligent collaborative treatment system for desulfurization wastewater from cement kilns according to claim 2, characterized in that, The neutralization reaction flocculation device (7) integrates a neutralization zone, a reaction zone, and a flocculation zone. Each zone is fed with lime powder, PAC, PAM, and organic sulfur materials by a dosing pump (8). The sedimentation device (9) uses a cone-shaped sedimentator, and the sediment is discharged through the sedimentation port at the bottom cone end.

7. The intelligent collaborative treatment system for desulfurization wastewater from cement kilns according to claim 1, characterized in that, Its control method includes the following steps: S1: Collects and adjusts water demand, collects dust concentration and equipment temperature signals in real time, and determines that there is a water demand when the dust concentration or equipment temperature is higher than the set value. It calculates the required water demand based on the signal feedback value and adjusts it in real time. When the dust concentration or temperature meets the emission and safety indicators, it gradually reduces the water demand until dynamic equilibrium is reached. S2: Predict water demand and adjust wastewater volume. Based on the changing pattern of water demand, predict the water demand in the future period and adjust the treatment rate of the neutralization reaction flocculation device (7) in advance so that the wastewater treatment capacity of the system always follows the actual water demand. S3: Dehydration and water demand balance control, receiving the signal from the filter cake moisture content detector (4), adjusting the dehydration time of the vacuum dehydrator and the opening of the electric regulating valve according to the preset target moisture content of the filter cake, the liquid level of the recycled water tank (11), the water demand, and the operating conditions of the pH value, liquid level and slurry density in the desulfurization tower, while dynamically matching the water supply of the gypsum slurry discharge pump; S4: Collect and adjust the dosage of chemicals. Collect and adjust the dosage of chemicals: Receive signals from the multi-parameter water quality analyzer (6) and the water quality analyzer (10), calculate the required dosage of chemicals according to the preset effluent water quality requirements and adjust it in real time. When the effluent water quality meets the reuse requirements, gradually reduce the dosage of chemicals to dynamic equilibrium. S5: Dehydration-Wastewater Treatment-Water Demand Co-optimization: Taking the synergy and operating cost of the above S1-S4 steps as the objective, the target moisture content of the filter cake, the quality of the effluent, the level of the recycled water tank, the predicted water demand, and the pH value, level and slurry density in the desulfurization tower are used as joint optimization variables, and the optimization algorithm is used for global adjustment.

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