Novel converter flue gas waste heat boiler dosing method

Abstract

A novel converter flue gas waste heat boiler chemical adding method comprises the steps that chemical adding amount calculation is conducted on parameters such as the volume, the pollution discharge period and the pollution discharge amount of a waste heat boiler, a simple chemical adding device is manufactured according to the chemical adding amount calculation result, and the water quality of the boiler is controlled through a periodic pollution discharge and chemical adding method. The amount of trisodium phosphate required to be added in the initial stage is measured according to the water volume and the content of trisodium phosphate; and setting a period addition amount by setting a pollution discharge period and pollution discharge amount. And the boiler water reaches each index range by periodically adding chemicals into the steam pocket. The problem of complex and tedious control of waste heat boiler dosing is solved, and boiler water quality is stabilized. The recovery efficiency of the waste heat boiler is greatly improved, the safety of the boiler is maintained, and the service life of the boiler is prolonged.

Description

Technical Field

[0001] The invention relates to the field of steelmaking and metallurgical equipment, in particular to a novel method for adding medicine to a converter flue gas waste heat boiler. Background Art

[0002] The flue gas waste heat boiler in the converter steelmaking process uses the high temperature flue gas generated in the converter steelmaking process to heat water to produce steam or hot water for various industrial applications such as power supply and heating. In this process, the boiler water is usually softened, but due to the complex quality of the converter water and its frequent use, the Ca content in the water is high. 2+ Mg 2+ Components such as plasma, suspended matter, and silicates (SiO2) still exist, and after repeated heating, they are prone to forming scaling substances such as CaCO3 and MgCO3. The deposition of scaling substances can reduce boiler heat exchange efficiency and may even cause serious problems such as equipment corrosion and failure. Therefore, effective measures must be taken to control water quality and prevent scaling.

[0003] At present, in the water quality control of converter flue gas waste heat boiler, trisodium phosphate is usually added to the drum water to alleviate or prevent the formation of scale. 2+ Mg 2+ The ions react to form water-soluble compounds or loose slag, which is discharged from the boiler through the blowdown device, effectively reducing the risk of scaling. By adding chemicals, the hardness and suspended matter content in the water can be effectively controlled, thereby reducing the negative impact of scaling on the boiler.

[0004] The traditional dosing method for converter flue gas waste heat boilers generally adopts continuous dosing, that is, the anti-scaling agent is continuously added to the boiler feed water or drum water at a certain concentration. This method uses a dosing device to quantitatively add the liquid medicine, but this method has some shortcomings. First, due to the volatility of boiler water quality, it is difficult to achieve stable control of water quality by continuous dosing. Excessive dosage of the agent may lead to over-treatment of the water quality, increase the usage and cost of the agent; insufficient dosage of the agent may not effectively prevent scaling and reduce the operating efficiency of the boiler. In addition, continuous dosing also requires frequent monitoring of water quality. The operation process is cumbersome, and the water quality detection is not accurate enough, resulting in a gap between the actual effect and the expected target. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a novel converter flue gas waste heat boiler dosing method.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a new converter flue gas waste heat boiler dosing method, comprising the following steps:

[0007] (1) Calculate the boiler water volume and the approved flue volume based on the calculated drum water level and flue volume;

[0008] (2) Determine the loss amount of periodic sewage discharge based on the water hardness and the concentration of trisodium phosphate used;

[0009] (3) Calculate the periodic dosage based on the dosage cycle, sewage discharge volume, and dosage of trisodium phosphate;

[0010] (4) Add deionized water to the water supply pipe of the dosing tank, add trisodium phosphate through the dosing hopper, prepare the agent into liquid, start the dosing pump and add the liquid into the steam drum;

[0011] (5) Check the boiler water quality index. If the water quality does not meet the standard, continue to add reagents. If the water quality exceeds the standard, start the drain valve to drain the waste heat boiler;

[0012] (6) Add medicine to the boiler according to the dosing cycle and the amount of medicine added during the cycle.

[0013] As a further improvement of the present invention: the dosage of trisodium phosphate in step (2) is 1 g / L, and the trisodium phosphate content of the water quality agent industrial phosphate is adjusted to 92%.

[0014] As a further improvement of the present invention: the step (3) includes calculating the steam drum operating volume and the flue volume.

[0015] As a further improvement of the present invention: the steam drum operating volume is calculated by the steam drum volume and the water level meter range.

[0016] As a further improvement of the present invention: in the step (4), 1000 L of desalted water is added to the water supply pipe of the dosing tank.

[0017] As a further improvement of the present invention: in step (4), 1m 3 Liquid

[0018] As a further improvement of the present invention: if the water quality index is not met in step (4), 1 kg of the agent is further added to prepare 100 ml of the liquid for dosing the waste heat boiler.

[0019] As a further improvement of the present invention: in the step (4), a liquid medicine storage device and a stirring device are provided in the medicine adding tank.

[0020] As a further improvement of the present invention, the dosing cycle and the blowdown volume are dynamically adjusted according to the boiler water quality and the blowdown loss, so as to achieve accurate control of the balance between the dosing volume and the blowdown volume.

[0021] As a further improvement of the present invention: in step (4), the dosing pump is connected to the water quality sensor through an intelligent control system to automatically adjust the dosing amount and the opening and closing of the sewage valve, and to provide real-time feedback control of the water quality.

[0022] As a further improvement of the present invention: in step (5), water quality detection and sewage discharge control are automatically completed through a PLC control system, reducing manual intervention.

[0023] Compared with existing technologies, this invention offers the following advantages: By accurately calculating parameters such as the waste heat boiler's volume, blowdown cycle, and blowdown volume, it determines the appropriate dosage and implements periodic dosing control using a simple dosing device. This dosing method significantly resolves the cumbersome control issues associated with traditional dosing methods by precisely regulating boiler water quality, stabilizing boiler water quality and effectively improving waste heat boiler operating efficiency.

[0024] By calculating the boiler drum and flue volume, the present invention can accurately calculate the boiler water volume and the required initial dosage of chemicals. Combining the blowdown cycle and discharge volume, and through periodic dosing, this not only ensures that boiler water quality remains within a reasonable range, but also avoids unbalanced chemical use and the adverse consequences of overdosing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to illustrate the technical solution more clearly, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 It is a structural schematic diagram of the present invention.

[0027] Reference numerals:

[0028] 1. Dosing hopper; 2. Dosing tank water supply pipe; 3. Dosing tank; 4. Water level gauge; 5. Drain valve; 6. Drain pipe; 7. Dosing valve; 8. Dosing pump; 9. Dosing pump outlet valve; 10. Dosing pipe check valve; 11. Drum water supply valve; 12. Drum water supply pipe check valve; 13. Waste heat boiler drum; 14. Downcomer; 15. Riser; 16. Vaporization flue; 17. Vaporization flue drain valve; 18. Mixer. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] During the converter steelmaking process, the high-temperature flue gas generated transfers heat energy to water through the waste heat boiler, thereby generating steam or hot water, which is widely used in industrial power supply, heating and other applications. However, although boiler water is usually softened, due to the complex quality of converter water and its frequent use, the Ca content in the water is high. 2+ Mg 2+ Components such as plasma, suspended matter, and silicates (SiO2) still exist. These substances easily form scaling materials such as CaCO3 and MgCO3 during repeated heating. Boiler scaling significantly reduces heat exchange efficiency and, in severe cases, can cause equipment corrosion and failure, impacting system stability. Therefore, effective measures must be taken to control water quality and prevent scaling.

[0032] At present, the water quality control of converter flue gas waste heat boiler usually adopts the method of adding trisodium phosphate to the drum water to prevent the formation of scale. 2+ Mg 2+ The plasma reacts to produce soluble compounds or loose water slag, which is discharged from the boiler through the blowdown device, thereby reducing the risk of scaling. This dosing method can effectively adjust the hardness and suspended solids content of water, reducing the adverse effects of scaling on the boiler.

[0033] However, traditional dosing methods mostly use continuous dosing, that is, anti-scaling agents are continuously added to the boiler feed water or drum water at a fixed concentration. Although this method uses a dosing device to quantitatively add the liquid medicine, it also has certain drawbacks. First, the quality of boiler water is often volatile, and continuous dosing makes it difficult to stably control the water quality. When the agent is excessive, it will cause excessive water treatment, increase the amount of agent used and the cost; when the agent is insufficient, it may not be able to effectively prevent scaling, resulting in reduced boiler efficiency. In addition, continuous dosing also requires frequent monitoring of water quality. The operation process is cumbersome, and the water quality test results are not accurate enough, which often leads to a large gap between the actual effect and the expected target.

[0034] Therefore, the traditional continuous dosing method has problems such as unstable water quality control, complex operation, and high cost. There is an urgent need for a more accurate, simple and efficient dosing method to improve the water quality control effect of waste heat boilers.

[0035] In order to solve the above problems, the present invention provides a novel converter flue gas waste heat boiler dosing method, comprising the following steps:

[0036] (1) Calculate the boiler water volume and the approved flue volume based on the calculated drum water level and flue volume;

[0037] (2) Determine the loss amount of periodic sewage discharge based on the water hardness and the concentration of trisodium phosphate used;

[0038] (3) Calculate the periodic dosage based on the dosage cycle, sewage discharge volume, and dosage of trisodium phosphate;

[0039] (4) Add deionized water to the water supply pipe of the dosing tank, add trisodium phosphate through the dosing hopper, prepare the agent into liquid, start the dosing pump and add the liquid into the steam drum;

[0040] (5) Check the boiler water quality index. If the water quality does not meet the standard, continue to add reagents. If the water quality exceeds the standard, start the drain valve to drain the waste heat boiler;

[0041] (6) Add medicine to the boiler according to the dosing cycle and the amount of medicine added during the cycle.

[0042] The present invention accurately calculates parameters such as the volume, blowdown cycle, and blowdown volume of the waste heat boiler to determine a reasonable dosage, and implements periodic dosing control through a simple dosing device.

[0043] As an embodiment of the present invention, the amount of trisodium phosphate used in step (2) is 1 g / L, and the trisodium phosphate content of the water quality agent industrial phosphate is adjusted to 92%;

[0044] By setting the dosage of trisodium phosphate to 1g / L, the concentration of the agent can be accurately controlled to ensure that the dosage matches the boiler water quality requirements. Reasonable dosage of the agent can effectively prevent excessive water treatment, avoid agent waste, and ensure that the agent has the best anti-scaling effect; trisodium phosphate is a commonly used water quality regulating agent with strong water softening and anti-scaling effects. In this solution, trisodium phosphate and Ca in water 2+ Mg 2+The plasma reaction generates water-soluble compounds or loose slag, effectively reducing scaling, ensuring stable boiler water quality and mitigating the risk of reduced heat exchange efficiency and equipment damage caused by scaling. Since trisodium phosphate (TSP) in industrial phosphates contains 92% TSP, this high concentration ensures that each dose is more effective, reducing the need for frequent changes or dosage adjustments. Compared to lower-content reagents, using 92% TSP reduces usage, improves chemical efficiency, and reduces operating costs. Precisely controlled dosages simplify and stabilize the dosing process. Frequent water quality monitoring and dosage adjustments are unnecessary, reducing operational complexity and the need for manual intervention. Appropriate TSP dosage helps maintain stable boiler water quality, reduces scaling and corrosion, and thus extends boiler life. It also ensures boiler heat exchange efficiency, improves waste heat recovery efficiency, and reduces energy consumption and maintenance costs.

[0045] As an embodiment of the present invention, the step (3) includes calculating the steam drum operating volume and the flue volume.

[0046] As an embodiment of the present invention, the drum operating volume is calculated by the drum volume and the water level meter range.

[0047] By accurately calculating the operating volume of the drum, the actual volume of water operating within the boiler can be precisely determined. The calculation of the drum's operating volume is based on the drum's volume and the water level meter range, enabling dynamic monitoring of water level changes during actual operation. This calculation method can promptly reflect fluctuations in the boiler's water volume, allowing adjustments to the reagent dosing strategy to ensure that the amount of reagent added matches the actual boiler's operating conditions. The drum's operating volume is a function of water level changes. By accurately calculating the relationship between the drum's volume and water level, changes in the water level can be stably monitored, further precisely controlling the timing and amount of reagent addition. Accurately calculating drum volume and water level changes helps better control boiler water quality, thereby avoiding problems such as scaling and corrosion, and ensuring the boiler is always in good operating condition.

[0048] As an embodiment of the present invention, in step (4), 1000L of deionized water is added to the water supply pipe of the dosing tank; in step (4), 1m 3 If the water quality index is not met, continue to add 1kg of the agent to prepare 100ml of liquid to add medicine to the waste heat boiler.

[0049] Add 1000L of desalted water to the dosing tank and prepare 1m 3The liquid medicine can ensure that the concentration of the liquid medicine is accurate and stable each time the medicine is added. This quantitative liquid medicine preparation method effectively avoids the uneven concentration of the liquid medicine during the dosing process, ensures that each portion of the medicine in the dosing process can be evenly mixed and added as needed, and avoids too much or too little medicine affecting the water quality control effect. During the dosing process, if the water quality indicators do not meet the set standards, the boiler water quality is ensured to meet the requirements by continuously adding the medicine (such as continuing to add 1kg of medicine to prepare 100L of liquid medicine). The dosage of the medicine is flexibly adjusted according to the real-time water quality monitoring results, making the dosing process more accurate and flexible, thereby ensuring that the boiler water quality is always in the best state and avoiding the negative impact of water quality fluctuations on boiler operation.

[0050] As an embodiment of the present invention, in step (4), a drug liquid storage device and a stirring device are provided in the drug adding tank, and the stirring device is used to uniformly prepare the drug to ensure the uniformity of the drug liquid.

[0051] The automated liquid preparation and stirring device reduces manual intervention and improves the accuracy and consistency of the dosing process. The equipment can adjust the dosage of the agent in real time according to changes in water quality, ensuring the accuracy of the agent delivery, reducing the complexity of manual intervention, and improving work efficiency and system stability. The method of preparing the liquid allows the dosage to be accurately calculated and directly added each time, avoiding waste of the agent. By adding the agent on demand (for example, continuing to add the agent when the water quality indicators are not up to standard), unnecessary use of the agent can be reduced. The addition of the stirring device not only improves the uniformity of the liquid, but also effectively avoids the problem of precipitation or agglomeration of the agent, ensuring the stability and safety of the liquid. At the same time, the entire dosing process is operated through an automatic control system, reducing operational errors and safety hazards, and improving the reliability and safety of the system.

[0052] As an embodiment of the present invention, the calculation cycle dosage is shown in the following table:

[0053]

[0054]

[0055] In the table, the initial dosage calculation is (C2 + C3) * C6. C2 refers to the loss from periodic blowdown. This refers to the amount of water lost from the boiler due to water quality control and blowdown operations within a specified period. This value needs to be estimated based on the frequency of blowdown and water quality losses. C3 refers to the dosage of trisodium phosphate, that is, the concentration or amount of trisodium phosphate required per unit of water. Assume that the concentration of trisodium phosphate is fixed, for example, 1g / L. C6 refers to the boiler water volume, that is, the amount of water in the boiler requiring dosing, either the volume of the steam drum or the actual volume of water in the boiler. Therefore, the logic for calculating the initial dosage is: first calculate the sum of the loss from periodic blowdown (C2) and the trisodium phosphate dosage (C3); then multiply this by the boiler water volume (C6) to obtain the required total dosage.

[0056] The calculation method for the cycle dosage in the table is C5*C4*C6. C4 refers to the number of days or time period in the dosing cycle. This refers to the frequency or interval of dosing within a unit of time. For example, if the dosing cycle is every three days, then C4 is three days. C5 refers to the dosage per cycle. This refers to the amount of trisodium phosphate required during a cycle, typically calculated based on the boiler's water quality or losses. C6 refers to the boiler's water or steam volume, specifically the volume of water to be dosed or the boiler's water capacity. Generally, the dosage is calculated based on the boiler's water volume to ensure optimal water quality. Therefore, the cycle dosage can be calculated as follows: C5 (dosage per cycle) multiplied by C4 (number of days or frequency of dosing) to determine the total dosage per cycle. This is then multiplied by C6 (boiler water or steam volume) to determine the dosage for the entire boiler system.

[0057] like Figure 1 As shown, the medicine tank 3 is provided with a dosing hopper 1, a dosing tank water supply pipe 2 and a mixer 18, a water level gauge 4 is provided on the medicine tank 3, a drain pipe 6 is provided on the lower side of the medicine tank 3, and a drain valve 5 is provided on the drain pipe 6. The medicine tank 3 is connected to the waste heat boiler drum 13, and the connecting pipeline is provided with a medicine outlet valve 7, a dosing pump 8, a dosing pump outlet valve 9, a dosing pipe check valve 10, a drum water supply valve 11, and a drum water supply pipe check valve 12; a downcomer 14 and an upcomer 15 are provided between the waste heat boiler drum 13 and the vaporization flue 16; and a vaporization flue drain valve 17 is provided on the vaporization flue 16.

[0058] The main functions of the present invention are:

[0059] (1) Stabilize boiler water quality and prevent boiler scaling: The present invention uses periodic dosing to prevent over- or under-dosing of trisodium phosphate and other chemicals. It also effectively avoids fluctuations in boiler water quality and maintains water stability. This effectively slows down or prevents boiler scaling, ensures boiler heat exchange efficiency, reduces maintenance and cleaning frequency, and extends boiler service life.

[0060] (2) Simplify the operation process and reduce enterprise management and control costs: By introducing a periodic dosing control method, the present invention greatly simplifies the dosing process and reduces the frequency of manual monitoring, testing, and adjustment. Enterprises no longer need to conduct frequent water quality testing and testing operations, thereby reducing management and control costs and improving operational simplicity. This not only reduces the workload of operators but also improves the work efficiency of enterprises.

[0061] (3) Solve the problem of excessive periodic dosing and avoid water quality exceeding standards: Traditional continuous dosing methods easily lead to excessive dosage of chemicals, which in turn causes boiler water quality indicators to exceed standards and brings difficulties to water quality control. In contrast, the present invention adopts a periodic dosing method based on specific parameter calculations, which can accurately control the dosage of chemicals, avoid the problems of excessive dosing and water quality exceeding standards, keep water quality within the appropriate range, and avoid unnecessary sewage discharge and chemical waste.

[0062] (4) Small production volume, low cost, and easy implementation: The periodic dosing method of the present invention does not require large-scale modification of the existing boiler system. The modification is small, installation and commissioning are simple, and will not cause a large increase in enterprise costs. The dosing control function can be achieved through the optimization and adjustment of existing equipment, and the modification cycle is short, which is convenient for rapid implementation.

[0063] (5) Simple structure, easy to manufacture and construct: The present invention adopts a simple dosing device and a periodic dosing system, with a simple structural design, easy manufacturing process, short construction period, and reduced construction period and construction difficulty. The dosing device can be easily connected to the existing boiler system, does not require complex technical support and equipment investment, and has high economic benefits.

[0064] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical solutions and technical concepts of the present invention without creative mental work, and all of them fall within the scope of protection of the present invention.

Claims

1. A novel converter flue gas waste heat boiler dosing method, characterized in that: The following steps are involved: (1) Calculate the boiler water volume and the approved flue volume based on the calculated drum water level and flue volume; (2) Determine the loss amount of periodic sewage discharge based on the water hardness and the concentration of trisodium phosphate used; (3) Calculate the periodic dosage based on the dosage cycle, sewage discharge volume, and dosage of trisodium phosphate; (4) Add deionized water to the water supply pipe of the dosing tank, add trisodium phosphate through the dosing hopper, prepare the agent into liquid, start the dosing pump and add the liquid into the steam drum; (5) Check the boiler water quality index. If the water quality does not meet the standard, continue to add reagents. If the water quality exceeds the standard, start the drain valve to drain the waste heat boiler; (6) Add medicine to the boiler according to the dosing cycle and the amount of medicine added during the cycle.

2. A novel converter flue gas waste heat boiler dosing method according to claim 1, characterized in that: The dosage of trisodium phosphate in step (2) is 1 g / L, and the trisodium phosphate content of the water quality agent industrial phosphate is adjusted to 92%.

3. The novel converter flue gas waste heat boiler dosing method according to claim 1 is characterized in that: The step (3) includes calculating the steam drum operating volume and the flue volume.

4. A novel converter flue gas waste heat boiler dosing method according to claim 3, characterized in that: The drum operating volume is calculated by the drum volume and the water level meter range.

5. The novel converter flue gas waste heat boiler dosing method according to claim 1 is characterized in that: In the step (4), 1000 L of deionized water is added to the water supply pipe of the dosing tank.

6. A novel converter flue gas waste heat boiler dosing method according to claim 5, characterized in that: In the step (4), 1 m 3 of liquid medicine.

7. A novel converter flue gas waste heat boiler dosing method according to claim 6, characterized in that: If the water quality index is not met in step (4), 1 kg of the reagent is added to prepare 100 ml of the reagent solution for dosing the waste heat boiler.

8. The novel converter flue gas waste heat boiler dosing method according to claim 1 is characterized in that: In the step (4), a drug liquid storage device and a stirring device are provided in the drug adding tank.

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