Drainage pipeline anti-corrosion device, heat supply system and drainage pipeline anti-corrosion method

Abstract

The invention discloses a drain pipeline anti-corrosion device, a heat supply system and a drain pipeline anti-corrosion method.The drain pipeline anti-corrosion device is characterized in that the data acquisition end of a control unit is connected with the data sending end of an oxygen-enriched water metering pump and used for obtaining a flow signal of the oxygen-enriched water metering pump; the output end of the control unit is connected with the control end of the oxygen-enriched water metering pump; the output end of the control unit is connected with the control end of the oxygen introduction unit; the output end of the oxygen introduction unit is connected with the input end of the oxygen-enriched water preparation unit, the output end of the oxygen-enriched water preparation unit is connected with the first end of the oxygen-enriched water metering pump, and the second end of the oxygen-enriched water metering pump is connected with an inlet of a drain pipe of the heating network heater. According to the drain pipe device, oxygen-enriched water is introduced into the drain pipe of the heating network heater, the oxygen content in the drain pipe is increased, a compact oxidation protection layer can be formed in the drain pipe, electrochemical reaction in the drain pipe is hindered, and flowing accelerated corrosion of the drain pipe is inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of power station systems, and in particular to a drainage pipeline anti-corrosion device, a heating system and a drainage pipeline anti-corrosion method. Background Art

[0002] Among the pipeline failure risks faced by nuclear power plants and large power plants in the existing technology, flow-accelerated corrosion ranks first, and pipelines experiencing flow-accelerated corrosion account for about 33% of the pipelines in power plants.

[0003] Flow-accelerated corrosion is a metal loss phenomenon caused by the combined action of electrochemical corrosion and physical erosion corrosion processes such as diffusion, mass transfer and deposition of corrosion products. The electrochemical process includes the ionization of the metal matrix Fe, the formation and chemical dissolution of the oxide film on the metal matrix surface. First, the magnetic oxide film on the surface of the metal matrix is ​​loose and porous. The metal matrix contacts the aqueous solution, and the metal matrix Fe forms a galvanic cell with the aqueous solution. Fe is ionized and loses electrons to generate Fe 2+ , part of Fe 2+ It reacts chemically with a small amount of Fe in the metal matrix under the action of an aqueous solution oxidant to form a magnetic Fe3O4 oxide film. The Fe3O4 oxide film is permeable and slightly soluble, and will chemically dissolve in water, causing the thickness of the oxide film to become thinner and the gap to increase, weakening the protective effect on the metal matrix of the pipeline, while enhancing the ionization of the metal matrix Fe, thinning the pipe wall, and accelerating the flow and corrosion rate.

[0004] Under the influence of flow-accelerated corrosion, the oxide protective film on the surface of the pipeline continues to dissolve and become thinner under the mainstream medium, resulting in a continuous decrease in the protective effect and increased corrosion, which is mainly manifested in accelerated pipeline scaling rate, valve blockage, increased pipeline pressure difference and thinning of the metal matrix. In severe cases, it will cause pipeline burst accidents, leakage of high-temperature working fluids, and unplanned shutdown of units, resulting in huge economic losses. Summary of the invention

[0005] The invention provides a drainage pipeline anti-corrosion device, a heating system and a drainage pipeline anti-corrosion method, so as to slow down or avoid flow-accelerated corrosion in the drainage pipeline.

[0006] According to one aspect of the present invention, there is provided a drainage pipeline anti-corrosion device, comprising: a control unit, an oxygen supply unit, an oxygen-enriched water preparation unit and an oxygen-enriched water metering pump;

[0007] The data acquisition end of the control unit is connected to the data sending end of the oxygen-enriched water metering pump to obtain the flow signal of the oxygen-enriched water metering pump;

[0008] The output end of the control unit is connected to the control end of the oxygen-enriched water metering pump to control the opening of the oxygen-enriched water metering pump; the output end of the control unit is connected to the control end of the oxygen supply unit to control the oxygen output flow of the oxygen supply unit;

[0009] The output end of the oxygen supply unit is connected to the input end of the oxygen-enriched water preparation unit, the output end of the oxygen-enriched water preparation unit is connected to the first end of the oxygen-enriched water metering pump, and the second end of the oxygen-enriched water metering pump is connected to the inlet of the heat network heater drain pipe.

[0010] Optionally, the oxygen-enriched water preparation unit comprises: a demineralized water metering pump, a mixing tank, a delivery pump, a balancing valve and a buffer tank;

[0011] The output end of the control unit is connected to the control end of the delivery pump and the control end of the balancing valve;

[0012] The data acquisition end of the control unit is connected to the data sending end of the mixing tank and the data sending end of the buffer tank, and is used to obtain the liquid level data signal and the pressure data signal of the mixing tank and the buffer tank;

[0013] The first end of the buffer tank is connected to the first end of the mixing tank through the balancing valve, and the second end of the buffer tank is connected to the second end of the mixing tank through the delivery pump;

[0014] The third end of the mixing tank is connected to the input end of the oxygen-enriched water preparation unit, and the third end of the buffer tank is connected to the output end of the oxygen-enriched water preparation unit;

[0015] The fourth end of the mixing tank is connected to the output end of the desalted water metering pump.

[0016] Optionally, the drainage pipe anti-corrosion device further includes: an electric valve;

[0017] The first end of the electric valve is connected to the output end of the oxygen-enriched water metering pump, and the second end of the electric valve is connected to the inlet of the drain pipe of the heating network heater;

[0018] The control end of the electric valve is connected to the output end of the control unit.

[0019] Optionally, the drainage pipeline anti-corrosion device further includes: a check valve;

[0020] The first end of the check valve is connected to the output end of the oxygen-enriched water metering pump, and the second end of the check valve is connected to the second end of the electric valve.

[0021] Optionally, the oxygen supply unit includes: a flow meter and an oxygen bus;

[0022] The control end of the flow meter is connected to the control end of the oxygen supply unit;

[0023] The first end of the flow meter is connected to the output end of the oxygen bus, and the second end of the flow meter is connected to the output end of the oxygen passing unit.

[0024] According to another aspect of the present invention, there is provided a heating system, comprising: a medium pressure cylinder, a low pressure cylinder, a heating network heater, a low temperature heat source heater, a return water network and a drainage pipe anti-corrosion device according to any embodiment of the present invention;

[0025] The air extraction end of the medium-pressure cylinder is connected to the air inlet of the heat network heater, the drain outlet end of the heat network heater is connected to the output end of the oxygen-enriched water metering pump of the drain pipe anti-corrosion device, the air extraction end of the low-pressure cylinder and the heat source inlet end of the low-temperature heat source heater, and the heat source outlet end of the low-temperature heat source heater is connected to the inlet of the heat recovery system;

[0026] The return water inlet end of the heating network heater is connected to the first end of the return water network, and the return water outlet end of the heating network heater is connected to the second end of the return water network; the return water inlet end of the low-temperature heat source heater is connected to the third end of the return water network, and the return water outlet end of the low-temperature heat source heater is connected to the fourth end of the return water network.

[0027] According to another aspect of the present invention, a method for anti-corrosion of a drain pipe is provided, which is applied to a device for anti-corrosion of a drain pipe in any embodiment of the present invention, comprising:

[0028] Setting the oxygen output flow rate of the oxygen supply unit to a target preset value;

[0029] Obtaining a set target dissolved oxygen value in the drain pipe anti-corrosion device;

[0030] Obtaining drainage parameters in the drainage pipeline;

[0031] Obtaining a target flow rate of an oxygen-enriched water metering pump in a drainage pipeline anti-corrosion device according to the set target dissolved oxygen value and the drainage parameter;

[0032] The opening degree of the oxygen-enriched water metering pump is controlled according to the target flow rate of the oxygen-enriched water metering pump.

[0033] Optionally, the obtaining of drainage parameters in the drainage pipeline includes:

[0034] Obtain the dissolved oxygen meter parameter signal at the end of the heating network heater drain system and the flow parameter signal of the heating network heater drain pump.

[0035] Optionally, obtaining the target flow rate of the oxygen-enriched water metering pump in the drainage pipeline anti-corrosion device according to the set target dissolved oxygen value and the drainage parameter includes:

[0036] The set target dissolved oxygen value and the drain parameter are input into the oxygenation control model, and the output result of the oxygenation control model is the target flow rate of the oxygen-enriched water metering pump in the drain pipe anti-corrosion device;

[0037] The expression of the oxygenation control model includes:

[0038] Q2=(K1(M2-M1)+K2M1e (M2-M1) )Q1×10 -3 ;

[0039] Among them, Q2 is the flow value of the oxygen-enriched water metering pump, K1 is the proportional coefficient, M2 is the parameter value of the dissolved oxygen meter at the end of the heat network heater drain system, M1 is the target dissolved oxygen value set by the drain pipe anti-corrosion device, K2 is the constraint coefficient, and Q1 is the flow value of the heat network heater drain pump.

[0040] Optionally, after controlling the opening of the oxygen-enriched water metering pump according to the target flow rate of the oxygen-enriched water metering pump, the method further includes:

[0041] The oxygen content value or steam hydrogen conductivity value of the water drain from the heating network heater is obtained, and when the oxygen content value or steam hydrogen conductivity value of the water drain from the heating network heater is greater than a preset threshold value, the oxygen-enriched water metering pump is controlled to be closed.

[0042] In the drain pipe anti-corrosion device, heating system and drain pipe anti-corrosion method of the embodiment of the present invention, in the drain pipe anti-corrosion device, the oxygen supply unit and the oxygen-enriched water preparation unit prepare oxygen-enriched water; the oxygen-enriched water metering pump adjusts its opening according to the control of the control unit to pass a fixed amount of oxygen-enriched water into the inlet of the drain pipe of the heating network heater. In the embodiment of the present invention, oxygen-enriched water is passed into the drain pipe to increase the oxygen content in the drain pipe. It helps to form a dense oxide protective layer in the drain pipe, hinders the electrochemical reaction in the drain pipe, and inhibits the flow-accelerated corrosion of the drain pipe. At the same time, the drain pipe anti-corrosion device of the embodiment of the present invention passes oxygen-enriched water into the drain pipe, which helps to accurately control the oxygen flow, maintain system stability and reduce pipeline impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0044] Figure 1 A drainage pipe anti-corrosion device provided by an embodiment of the present invention;

[0045] Figure 2 Another anti-corrosion device for drain pipes provided in an embodiment of the present invention;

[0046] Figure 3 Another anti-corrosion device for drain pipes provided in an embodiment of the present invention;

[0047] Figure 4 Another anti-corrosion device for drain pipes provided in an embodiment of the present invention;

[0048] Figure 5 A heating system provided by an embodiment of the present invention;

[0049] Figure 6 A method for preventing corrosion of a drainage pipe provided by an embodiment of the present invention;

[0050] Figure 7 Another anti-corrosion method for drain pipes provided by an embodiment of the present invention;

[0051] Figure 8 Another anti-corrosion method for a drain pipe is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0053] It should be noted that the terms "first", "second", etc. in the specification 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 data 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 that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0054] Figure 1 A drainage pipe anti-corrosion device provided by an embodiment of the present invention, such as Figure 1As shown, the drainage pipe anti-corrosion device provided by the embodiment of the present invention includes: a control unit 101, an oxygen-passing unit 102, an oxygen-enriched water preparation unit 103 and an oxygen-enriched water metering pump 104; the data acquisition end of the control unit 101 is connected to the data sending end of the oxygen-enriched water metering pump 104, for obtaining the flow signal of the oxygen-enriched water metering pump 104; the output end of the control unit 101 is connected to the control end of the oxygen-enriched water metering pump 104, for controlling the opening of the oxygen-enriched water metering pump 104; the output end of the control unit 101 is connected to the control end of the oxygen-passing unit 102, for controlling the oxygen output flow of the oxygen-passing unit 102; the output end of the oxygen-passing unit 102 is connected to the input end of the oxygen-enriched water preparation unit 103, the output end of the oxygen-enriched water preparation unit 103 is connected to the first end of the oxygen-enriched water metering pump 104, and the second end of the oxygen-enriched water metering pump 104 is connected to the inlet of the drainage pipe of the heat network heater.

[0055] Specifically, the oxygen supply unit 102 provides an oxygen source for the oxygen-enriched water preparation unit 103. The control unit 101 also sends a control instruction to the oxygen supply unit 102 through the output end to adjust its oxygen output flow rate to meet the oxygen demand in the oxygen-enriched water preparation process. In the oxygen-enriched water preparation unit 103, desalted water is mixed with oxygen to prepare oxygen-enriched water. The oxygen-enriched water metering pump 104 is a flow control device for adjusting the flow rate of oxygen-enriched water. The control unit 101 obtains the flow signal of the oxygen-enriched water metering pump 104 through the data acquisition end to monitor the flow rate of the oxygen-enriched water in real time. After the preparation of the oxygen-enriched water is completed, it is accurately measured by the oxygen-enriched water metering pump 104 and injected into the inlet of the heat network heater drain pipe to improve the corrosive environment in the drain pipe. The control unit 101 sends a control instruction to the oxygen-enriched water metering pump 104 through the output end to adjust its opening to accurately control the flow rate of the oxygen-enriched water.

[0056] The oxygen content of the oxygen-enriched water can be precisely controlled by adjusting the oxygen input of the oxygen supply unit 102 during the preparation process. By adjusting the preparation parameters of the oxygen-enriched water, the oxygen content input into the drain pipe can be flexibly adjusted to meet different needs. At the same time, in a high-pressure or high-temperature environment, direct oxygen supply may pose a risk of leakage or explosion, while oxygen-enriched water is relatively safer and more stable. Therefore, indirect oxygen supply through oxygen-enriched water is beneficial to improving the safety of the drain pipe system. In addition, for the drain pipe, under high flow or high pressure conditions, oxygen-enriched water is used as a liquid medium, and the flow of oxygen-enriched water has a relatively small impact on the pipe, which helps to protect the pipe structure.

[0057] Optionally, the output terminal and the data acquisition terminal of the control unit 101 are connected to the oxygen-enriched water preparation unit 103. The control unit 101 controls the oxygen-enriched water preparation of the oxygen-enriched water preparation unit 103 by monitoring the state of the oxygen-enriched water preparation unit 103.

[0058] Exemplarily, the flow-accelerated corrosion rate of pipelines is mainly affected by factors such as the shape, material, environment of the pipeline, pH, conductivity, and oxygen content of the working fluid. The iron ion content in the working fluid can directly reflect the flow-accelerated corrosion rate of the pipeline. The increase in oxygen content can effectively inhibit flow-accelerated corrosion. When the hydrogen conductivity of the heat network heater hydrophobicity is less than 0.15μS / cm, the hydrophobic pipeline is prone to flow-accelerated corrosion. The hydrophobic pipeline anti-corrosion device introduces oxygen-rich water into the inlet of the heat network heater hydrophobic pipe to increase the dissolved oxygen mass concentration of the hydrophobicity and increase the pH value of the hydrophobicity, thereby producing a metal passivation effect on the metal surface of the pipeline, forming a double-layer oxide film on the metal surface, the inner layer is a magnetic Fe3O4 oxide film close to the surface of the metal substrate, and the outer layer is a dense protective layer of Fe2O3 and hydrated iron oxide oxide film. The dense oxide film hinders the electrochemical reaction and reduces the Fe 2 + diffusion, reducing the flow accelerated corrosion rate.

[0059] In an embodiment of the present invention, a drain pipe anti-corrosion device is provided, wherein an oxygen supply unit and an oxygen-enriched water preparation unit prepare oxygen-enriched water; the oxygen-enriched water metering pump adjusts its opening according to the control of the control unit to pass a fixed amount of oxygen-enriched water into the inlet of the drain pipe of the heating network heater. In an embodiment of the present invention, oxygen-enriched water is passed into the drain pipe to increase the oxygen content in the drain pipe. This helps to form a dense oxide protective layer in the drain pipe, hinders the electrochemical reaction in the drain pipe, and inhibits the flow-accelerated corrosion of the drain pipe. At the same time, the drain pipe anti-corrosion device of the embodiment of the present invention passes oxygen-enriched water into the drain pipe, which helps to accurately control the oxygen flow, maintain system stability, and reduce pipeline impact.

[0060] Based on the above embodiments, Figure 2 Another anti-corrosion device for drain pipes provided by an embodiment of the present invention is as follows: Figure 2As shown, in the drainage pipe anti-corrosion device provided by the embodiment of the present invention, the oxygen-enriched water preparation unit 103 includes: a desalted water metering pump 1031, a mixing tank 1032, a delivery pump 1035, a balancing valve 1034 and a buffer tank 1033; the output end of the control unit 101 is connected to the control end of the delivery pump 1035 and the control end of the balancing valve 1034; the data acquisition end of the control unit 101 is connected to the data sending end of the mixing tank 1032 and the data sending end of the buffer tank 1033, so as to obtain the data of the mixing tank 1032 and the buffer tank 1033; the first end of the buffer tank 1033 is connected to the first end of the mixing tank 1032 through a balancing valve 1034, and the second end of the buffer tank 1033 is connected to the second end of the mixing tank 1032 through a delivery pump 1035; the third end of the mixing tank 1032 is connected to the input end of the oxygen-enriched water preparation unit 103, and the third end of the buffer tank 1033 is connected to the output end of the oxygen-enriched water preparation unit 103; the fourth end of the mixing tank 1032 is connected to the output end of the desalted water metering pump 1031.

[0061] Specifically, the desalted water metering pump 1031 delivers the desalted water to the mixing tank 1032 at a certain flow rate and pressure. Among them, the desalted water is pure water that has been treated to remove most of the minerals and impurities. The use of desalted water helps to reduce the impact of impurities in the water on the oxygen-enriched water preparation process, thereby improving the quality of oxygen-enriched water. In the mixing tank 1032, the desalted water is mixed with oxygen. The mixing tank 1032 ensures that oxygen can be fully dissolved in the water to increase the dissolved oxygen content in the water to form oxygen-enriched water. The buffer tank 1033 is used to store and adjust the pressure and flow of oxygen-enriched water. In the process of preparing oxygen-enriched water, the oxygen-enriched water flows from the mixing tank to the buffer tank, and the buffer tank 1033 can absorb pressure fluctuations to ensure that the oxygen-enriched water is output at a stable pressure and flow rate. The balancing valve 1034 is used to connect the mixing tank and the buffer tank, and the balancing valve 1034 is turned on or off to adjust the pressure balance between the two. During the preparation of oxygen-enriched water, the balancing valve 1034 can ensure that the pressure difference between the mixing tank 1032 and the buffer tank 1033 is maintained within a safe range, thereby preventing equipment damage or safety hazards caused by excessively high or low pressure.

[0062] Optionally, the opening of the desalted water flow pump 1031 is a fixed value, and the opening of the desalted water flow pump 1031 is determined when debugging the equipment according to the actual conditions of different power plants. When the desalted water metering pump 1031 is started, the interlocking delivery pump 1035 is not started.

[0063] The control unit 101 collects the liquid level data signals and the pressure data signals of the mixing tank 1032 and the buffer tank 1033 , and controls the on and off of the delivery pump 1035 and the balance valve 1034 according to the liquid level data signals and the pressure data signals.

[0064] Exemplarily, when the desalted water metering pump 1031 is turned off and there is no oxygen input to the oxygen-enriched water preparation unit 103, the liquid level data signal and the pressure data signal of the buffer tank 1033 are collected: when the liquid level of the buffer tank 1033 is less than the first liquid level height, the delivery pump 1035 is started to fill the buffer tank 1033 with water to the second liquid level height; when the pressure of the buffer tank 1033 exceeds the first pressure threshold, the balance valve 1034 is opened to deliver oxygen to the mixing tank 1032 to reduce the oxygen partial pressure above the buffer tank 1033. Optionally, the first liquid level height is one-half of the capacity height of the buffer tank 1033; the second liquid level height is five-sixths of the capacity height of the buffer tank 1033; and the first pressure threshold is 0.5MPa.

[0065] The output end of the control unit 101 is connected to the control end of the desalted water metering pump 1031, and the control unit 101 controls the switch of the salt water flow pump 1031 according to the liquid level data signals of the mixing tank 1032 and the buffer tank 1033. Collect the liquid level data signal of the buffer tank 1033: when the liquid level of the mixing tank 1032 is greater than the third liquid level height and less than the fourth liquid level height, the control unit 101 controls the desalted water metering pump 1031 to turn on; when the liquid level of the mixing tank 1032 is greater than the fourth liquid level height, the control unit 101 controls the desalted water metering pump 1031 to turn off. Optionally, the third liquid level height is one-third of the capacity height of the mixing tank 1032; the fourth liquid level height is two-thirds of the capacity height of the mixing tank 1032.

[0066] Based on the above embodiments, Figure 3 Another anti-corrosion device for drain pipes provided by an embodiment of the present invention is as follows: Figure 3 As shown, the anti-corrosion device for drain pipes provided in the embodiment of the present invention further includes: an electric valve 106; the first end of the electric valve 106 is connected to the output end of the oxygen-enriched water metering pump 104, and the second end of the electric valve 106 is connected to the inlet of the drain pipe of the heating network heater; the control end of the electric valve 106 is connected to the output end of the control unit 101. The anti-corrosion device for drain pipes provided in the embodiment of the present invention further includes: a check valve 105; the first end of the check valve 105 is connected to the output end of the oxygen-enriched water metering pump 104, and the second end of the check valve 105 is connected to the second end of the electric valve 106.

[0067] Specifically, in the drainage pipe anti-corrosion device, an electric valve 106 is provided between the drainage pipe inlet of the heating network heater and the output end of the oxygen-enriched water metering pump 104. The electric valve 106 can be turned on or off according to the control signal of the control unit 101.

[0068] When oxygen is passed through the drain pipe, the surface of the sediment layer of the drain pipe is converted into stable Fe2O3, and the micropores of the Fe3O4 film layer are blocked, making the protective layer denser, and forming a uniform and dense Fe2O3+Fe3O4 double-layer protective film on the carbon steel surface, thereby inhibiting the flow-accelerated corrosion of the drain system. At the same time, the addition of oxidants causes the carbon steel potential to reach the Fe2O3 passivation zone from the magnetic Fe3O4 stable zone, thereby forming a dense and stable protective oxide film on the metal surface.

[0069] However, when the amount of oxygen-enriched water introduced into the drain pipe is too high, the oxygen-enriched water, as a strong oxidant, will accelerate the oxidation reaction of metal materials and increase the corrosion rate of equipment. At the same time, when the oxygen content in the drain pipe is too high and the protective oxide film formed on the metal surface is too thick, the oxides and other sediments in the pipe are more likely to accumulate in the pipe to block the pipe, affecting the normal flow of the drain and even causing system failure.

[0070] The electric valve 106 is arranged between the inlet of the heat network heater drain pipe and the output end of the oxygen-enriched water metering pump 104. When the control unit 101 detects that the oxygen content of the heat network heater drain or the steam hydrogen conductivity is greater than the preset threshold, the electric valve 106 is turned off, and the drain pipe anti-corrosion device stops passing oxygen into the drain pipe. This is conducive to ensuring that oxygen-enriched water is passed into the drain at an appropriate flow rate and concentration, and is conducive to strictly controlling the oxygen-enriched water content, ensuring the safe, stable and efficient operation of the system.

[0071] In the drain pipe protection device, the check valve 105 is located between the oxygen-enriched water metering pump 104 and the electric valve 106. The check valve 105 is used to prevent the drain in the drain pipe from flowing back into the drain pipe anti-corrosion device.

[0072] Based on the above embodiments, Figure 4 Another anti-corrosion device for drain pipes provided by an embodiment of the present invention is as follows: Figure 4 As shown, in the drain pipe anti-corrosion device provided by the embodiment of the invention, the oxygen supply unit 102 includes: a flow meter 1021 and an oxygen bus 1022; the control end of the flow meter 1021 is connected to the control end of the oxygen supply unit 102; the first end of the flow meter 1021 is connected to the output end of the oxygen bus 1022, and the second end of the flow meter 1021 is connected to the output end of the oxygen supply unit 102.

[0073] Specifically, the flow meter 1021 is a flow control device for adjusting the flow of oxygen. The oxygen bus 1022 is an oxygen supply device for storing and distributing oxygen.

[0074] The flow meter 1021 receives oxygen from the oxygen bus 1022 and adjusts its opening according to the instruction of the control unit 101, thereby controlling the amount of oxygen entering the oxygen-enriched water preparation unit 103. Optionally, the opening of the gas flow meter 1021 can also be determined when debugging the equipment according to the actual situation of different power plants, and it will not be changed at will after being determined.

[0075] Exemplarily, based on the above embodiments, the control unit 101 controls the flow meter 1021 to be turned on or off according to the equipment status in the oxygen-enriched water preparation unit 1032. The data acquisition terminal of the control unit 101 collects the pressure data signal of the mixing tank 1032 in the oxygen-enriched water preparation unit 103. When the pressure of the mixing tank 1032 is greater than the second pressure threshold and less than the third pressure threshold, the control unit 101 controls the flow meter 1021 to be turned on; when the pressure of the mixing tank 1032 is greater than the third pressure threshold, the control unit 101 controls the flow meter 1021 to be turned on. Optionally, the second pressure threshold is 0.3MPa; the third pressure threshold is 0.5MPa. At the same time, when the gas flow meter 1021 is started, the delivery pump 1035 can be interlocked and not started.

[0076] Based on the above embodiments, Figure 5 A heating system provided by an embodiment of the present invention, such as Figure 5 As shown, the heating system provided by the embodiment of the present invention includes: a medium-pressure cylinder 02, a low-pressure cylinder 03, a heat network heater 04, a low-temperature heat source heater 05, a return water network 06 and a drain pipe anti-corrosion device 01 in any embodiment of the present invention; the suction end of the medium-pressure cylinder 02 is connected to the air inlet of the heat network heater 04, the drain outlet end of the heat network heater 04 is connected to the output end of the oxygen-enriched water metering pump 104 of the drain pipe anti-corrosion device 01, the suction end of the low-pressure cylinder 03 and the heat source inlet end of the low-temperature heat source heater 05, and the heat source outlet end of the low-temperature heat source heater 05 is connected to the inlet of the heat recovery system; the return water inlet end of the heat network heater 04 is connected to the first end of the return water network 06, and the return water outlet end of the heat network heater 04 is connected to the second end of the return water network 06; the return water inlet end of the low-temperature heat source heater 05 is connected to the third end of the return water network 06, and the return water outlet end of the low-temperature heat source heater 05 is connected to the fourth end of the return water network 06.

[0077] Specifically, the intermediate pressure cylinder 02 is a component of the steam turbine unit, receiving the steam discharged from the high pressure cylinder and the reheated steam. In the heating system of the embodiment of the present invention, the exhaust end of the intermediate pressure cylinder 02 is used to provide steam for heating, and the steam output from the exhaust end of the intermediate pressure cylinder 02 is input to the air inlet of the heating network heater 04.

[0078] As a heat exchange device, the heat network heater 04 uses the steam extracted from the medium pressure cylinder 02 to heat the return water in the return water network 06. The steam releases heat in the heat network heater, which increases the return water temperature in the return water network 06 to meet the heating demand. The air inlet is the heat source inlet, and the return water inlet end of the heat network heater 04 is the return water input end in the return water network 06; the heat network heater 04 also has a drain outlet end and a return water outlet end. The drain outlet end discharges the drain generated during the heating process, and the return water outlet end outputs the heated high-temperature water.

[0079] The return water network 06 is a pipe network for circulating return water. The return water flows out from the heating area, is heated by the heating network heater, and then flows back to the heating area. The heating area includes the heating network users.

[0080] The drain outlet of the heat network heater 04 is connected to the exhaust end of the low-pressure cylinder 03 and the heat source inlet end of the low-temperature heat source heater 05, and the heat source outlet end of the low-temperature heat source heater 05 is connected to the inlet of the heat recovery system; the return water inlet end of the low-temperature heat source heater 05 is connected to the third end of the return water network 06, and the return water outlet end of the low-temperature heat source heater 05 is connected to the fourth end of the return water network 06. The low-temperature heat source heater 05 receives drain and low-pressure cylinder exhaust as heat sources to heat the return water of the return water network. Exemplarily, the drain is cooled from 150°C to 50°C after passing through the low-temperature heat source heat exchanger, and the return water of the return water network is heated from 70°C to 130°C, and returns to the return water pipeline of the heat network for circulation.

[0081] The drain flowing out of the heat source outlet of the low-temperature heat source heater 05 enters the heat recovery system, wherein the heat recovery system refers to a component of the thermal system in the power plant. Exemplarily, the heat recovery system includes: a condenser hot well or a low-pressure heater. The condenser hot well is used to gather condensate condensed from the exhaust steam of the steam turbine. The condensate is collected and stored in the hot well for subsequent use. The low-pressure heater uses steam at a lower pressure to further heat the drain. As the drain flows through each heater, its temperature gradually increases. Finally, the drain is heated to a temperature close to or reaching a preset temperature and is sent to a boiler or other water-using equipment.

[0082] The drain outlet of the heating network heater 04 is used as an oxygenation point, and the output end of the oxygen-enriched water metering pump 104 of the drain pipe anti-corrosion device 01 outputs oxygen-enriched water to the drain outlet of the heating network heater 04, thereby increasing the oxygen content of the drain in the drain pipe to avoid flow-accelerated corrosion.

[0083] In the heating system provided by the embodiment of the present invention, the heat source of the heat network heater comes from the medium pressure cylinder of the steam turbine unit. After the heat network heater heats the return water in the return water network, the drain is discharged through the drain outlet of the heat network heater. The output end of the oxygen-enriched water metering pump of the drain pipe anti-corrosion device is connected to the drain outlet of the heat network heater. The drain pipe anti-corrosion device passes oxygen-enriched water into the drain pipe, which is conducive to the formation of a dense oxidation protection layer in the drain pipe, hindering the electrochemical reaction in the drain pipe and inhibiting the flow-accelerated corrosion of the drain pipe.

[0084] Based on the above embodiments, Figure 6 The present invention provides a method for preventing corrosion of a drain pipe. The present invention is applicable to preventing corrosion of the drain pipe caused by flow acceleration. The method for preventing corrosion of a drain pipe can be applied to the device for preventing corrosion of a drain pipe in any embodiment of the present invention. Figure 6 As shown, the anti-corrosion method for drain pipes provided by the embodiment of the present invention includes:

[0085] S201, setting the oxygen output flow rate of the oxygen supply unit to a target preset value.

[0086] Specifically, Figure 1-6 As shown, in the drainage pipe anti-corrosion device, the oxygen supply unit 102 provides an oxygen source for the oxygen-enriched water preparation unit 103. The oxygen output flow rate of the oxygen supply unit 102 is set to a target preset value. The oxygen output flow rate of the oxygen supply unit 102 is determined when the equipment is debugged according to the actual conditions of different power plants, and will not be changed at will after being determined.

[0087] S202: Obtain a set target dissolved oxygen value in the drainage pipe anti-corrosion device.

[0088] Specifically, Figures 1 to 5 In the drain pipe anti-corrosion device 01, a target dissolved oxygen value is set. The specific value of the target oxygen content is determined by the actual operation of the power plant. Optionally, the target dissolved oxygen value is set between 20 and 80 μg / L. Setting the target dissolved oxygen value can provide the drain pipe with sufficient oxygen-rich water to form a dense oxide film to avoid accelerated corrosion of the drain pipe flow; it can also avoid problems such as excessively thick oxide layer and intensified corrosion reaction caused by excessive oxygen-rich water.

[0089] S203, obtaining drainage parameters in the drainage pipeline.

[0090] Specifically, the drainage parameters in the drainage pipeline include: the dissolved oxygen meter value at the end of the heating network heater drainage system and the flow value of the heating network heater drainage pump.

[0091] Exemplarily, the sensor or instrument on the drain pipe obtains the dissolved oxygen meter signal at the end of the heat network heater drain system and the flow signal of the heat network heater drain pump. The dissolved oxygen meter value at the end of the heat network heater drain system and the flow value of the heat network heater drain pump reflect the actual oxygen content in the drain pipe and the flow rate of the drain.

[0092] S204. Obtain a target flow rate of an oxygen-enriched water metering pump in a drainage pipeline anti-corrosion device according to a set target dissolved oxygen value and drainage parameters.

[0093] Calculate and determine the oxygen-enriched water flow rate that the oxygen-enriched water metering pump 104 needs to provide to achieve the set target dissolved oxygen value. Optionally, the target flow rate of the oxygen-enriched water metering pump 104 is calculated based on the target dissolved oxygen value, the actual dissolved oxygen value and the drain flow value through an algorithm or model.

[0094] S205. Control the opening of the oxygen-enriched water metering pump according to the target flow rate of the oxygen-enriched water metering pump.

[0095] Specifically, according to the target flow rate of the oxygen-enriched water metering pump, the control unit 101 adjusts the opening degree of the oxygen-enriched water metering pump 104 so that the actual oxygen-enriched water flow rate matches the target flow rate.

[0096] In the anti-corrosion method for drain pipes of the embodiment of the present invention, accurate control of the amount of oxygen-enriched water introduced into the drain pipe by the anti-corrosion device for drain pipes is achieved by setting a target dissolved oxygen value, obtaining drain parameters, calculating a target flow rate, and controlling the opening of an oxygen-enriched water metering pump. This method helps prevent flow-accelerated corrosion in drain pipes and improves the operating efficiency and safety of power plants.

[0097] Based on the above embodiments, Figure 7 Another anti-corrosion method for drain pipes provided by an embodiment of the present invention is as follows: Figure 7 As shown, the anti-corrosion method for drain pipes provided in the embodiment of the present invention also includes:

[0098] S301, setting the oxygen output flow rate of the oxygen supply unit to a target preset value.

[0099] S302, obtaining a set target dissolved oxygen value in the drainage pipe anti-corrosion device.

[0100] S303, obtaining the dissolved oxygen meter parameter signal at the end of the heating network heater drain system and the flow parameter signal of the heating network heater drain pump.

[0101] Specifically, the dissolved oxygen meter parameter signal at the end of the heat network heater drain system reflects the dissolved oxygen level at the end of the drain pipe (ie, the outlet of the heat network heater drain system). The heat network heater drain pump flow parameter signal represents the flow of the drain pump, ie, the water flow rate in the drain pipe.

[0102] S304, setting a target dissolved oxygen value and drain parameters and inputting them into an oxygenation control model, the output result of the oxygenation control model is a target flow rate of an oxygen-enriched water metering pump in the drain pipe anti-corrosion device.

[0103] Among them, the expression of the oxygen addition control model includes:

[0104] Q2=(K1(M2-M1)+K2M1e (M2-M1) )Q1×10 -3 ;

[0105] Among them, Q2 is the flow value of the oxygen-enriched water metering pump 104, K1 is the proportional coefficient, M2 is the parameter value of the dissolved oxygen table at the end of the heat network heater 04 drain system, M1 is the target dissolved oxygen value set by the drain pipe anti-corrosion device, K2 is the constraint coefficient, and Q1 is the flow value of the heat network heater 04 drain pump.

[0106] Specifically, the proportional coefficient K1 and the constraint coefficient K2 are set manually according to the actual situation. The proportional coefficient K1 adjusts the difference between the set target dissolved oxygen value (hereinafter referred to as the target value) and the dissolved oxygen table parameter value at the end of the heat network heater drain system (hereinafter referred to as the actual value), which is the adjustment ratio of the flow control of the oxygen-enriched water metering pump 104. The constraint coefficient K2 controls the actual value to be stable near the target value.

[0107] For example, for a unit with a relatively stable drain flow rate of a heating network heater, the setting value of the corresponding proportional coefficient K1 is relatively large and the setting value of the constraint coefficient K2 is relatively small. At this time, the drain flow rate changes slightly, and the flow rate of the oxygen-enriched water flow pump tends to be stable.

[0108] When the flow fluctuation of the heat network heater drain is relatively large, the setting value of the corresponding proportional coefficient K1 is relatively small and the setting value of the constraint coefficient K2 is relatively large. Since the difference between the actual value and the target value caused by the flow fluctuation changes dramatically, the smaller the proportional coefficient K1, the smaller the impact of the difference between the actual value and the target value; the larger the constraint coefficient K2, the better the neutralization when the actual value deviates greatly from the target value, and the better stability when the actual value is close to the target value.

[0109] S305. Control the opening of the oxygen-enriched water metering pump according to the target flow rate of the oxygen-enriched water metering pump.

[0110] Based on the above embodiments, Figure 8 Another anti-corrosion method for drain pipes provided by an embodiment of the present invention is as follows: Figure 8 As shown, the anti-corrosion method for drain pipes provided in the embodiment of the present invention also includes:

[0111] S401, setting the oxygen output flow rate of the oxygen supply unit to a target preset value.

[0112] S402: Obtain a set target dissolved oxygen value in the drainage pipe anti-corrosion device.

[0113] S403, obtaining drainage parameters in the drainage pipeline.

[0114] S404. Obtain a target flow rate of an oxygen-enriched water metering pump in a drainage pipeline anti-corrosion device according to a set target dissolved oxygen value and drainage parameters.

[0115] S405. Control the opening of the oxygen-enriched water metering pump according to the target flow rate of the oxygen-enriched water metering pump.

[0116] S406, obtaining the oxygen content value or steam hydrogen conductivity value of the heat network heater drain, and when the oxygen content value or steam hydrogen conductivity value of the heat network heater drain is greater than a preset threshold, controlling the oxygen-enriched water metering pump to close.

[0117] Specifically, when the oxygen content in the drain of the heating network heater is too high, the excessive oxygen content in the drain will react with the metal equipment to cause oxidation, which will accelerate the corrosion of the equipment. When the hydrogen conductivity of the drain is high, the ion content in the system is high, which will also accelerate the oxygen evolution corrosion of the iron of the pipeline matrix. Therefore, the preset thresholds of the oxygen content value and steam hydrogen conductivity value of the drain of the heating network heater are set. The oxygen content value or steam hydrogen conductivity value of the drain of the heating network heater is collected in real time and compared with the preset threshold value; when the oxygen content value or steam hydrogen conductivity value of the drain of the heating network heater is greater than the preset threshold value, the oxygen-enriched water metering pump is controlled to be closed.

[0118] Optionally, the preset threshold value of the oxygen content value of the heat network heater drain is 80 μg / L; the preset threshold value of the steam hydrogen conductivity value is 0.15 μS / cm.

[0119] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0120] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A drainage pipe anti-corrosion device, characterized in that: include: Control unit, oxygen supply unit, oxygen-enriched water preparation unit and oxygen-enriched water metering pump; The data acquisition end of the control unit is connected to the data sending end of the oxygen-enriched water metering pump to obtain the flow signal of the oxygen-enriched water metering pump; The output end of the control unit is connected to the control end of the oxygen-enriched water metering pump to control the opening of the oxygen-enriched water metering pump; the output end of the control unit is connected to the control end of the oxygen supply unit to control the oxygen output flow of the oxygen supply unit; The output end of the oxygen supply unit is connected to the input end of the oxygen-enriched water preparation unit, the output end of the oxygen-enriched water preparation unit is connected to the first end of the oxygen-enriched water metering pump, and the second end of the oxygen-enriched water metering pump is connected to the inlet of the heat network heater drain pipe.

2. The drainage pipe anti-corrosion device according to claim 1, characterized in that: The oxygen-enriched water preparation unit comprises: a demineralized water metering pump, a mixing tank, a delivery pump, a balancing valve and a buffer tank; The output end of the control unit is connected to the control end of the delivery pump and the control end of the balancing valve; The data acquisition end of the control unit is connected to the data sending end of the mixing tank and the data sending end of the buffer tank, and is used to obtain the liquid level data signal and the pressure data signal of the mixing tank and the buffer tank; The first end of the buffer tank is connected to the first end of the mixing tank through the balancing valve, and the second end of the buffer tank is connected to the second end of the mixing tank through the delivery pump; The third end of the mixing tank is connected to the input end of the oxygen-enriched water preparation unit, and the third end of the buffer tank is connected to the output end of the oxygen-enriched water preparation unit; The fourth end of the mixing tank is connected to the output end of the desalted water metering pump.

3. The drainage pipe anti-corrosion device according to claim 1, characterized in that: The drainage pipeline anti-corrosion device also includes: an electric valve; The first end of the electric valve is connected to the output end of the oxygen-enriched water metering pump, and the second end of the electric valve is connected to the inlet of the drain pipe of the heating network heater; The control end of the electric valve is connected to the output end of the control unit.

4. The drainage pipe anti-corrosion device according to claim 3, characterized in that: The drainage pipeline anti-corrosion device also includes: a check valve; The first end of the check valve is connected to the output end of the oxygen-enriched water metering pump, and the second end of the check valve is connected to the second end of the electric valve.

5. The drainage pipe anti-corrosion device according to claim 1, characterized in that: The oxygen supply unit comprises: a flow meter and an oxygen bus; The control end of the flow meter is connected to the control end of the oxygen supply unit; The first end of the flow meter is connected to the output end of the oxygen bus, and the second end of the flow meter is connected to the output end of the oxygen passing unit.

6. A heating system, characterized in that: include: A medium-pressure cylinder, a low-pressure cylinder, a heat network heater, a low-temperature heat source heater, a return water network, and a drainage pipe anti-corrosion device according to any one of claims 1 to 5 above; The air extraction end of the medium-pressure cylinder is connected to the air inlet of the heat network heater, the drain outlet end of the heat network heater is connected to the output end of the oxygen-enriched water metering pump of the drain pipe anti-corrosion device, the air extraction end of the low-pressure cylinder and the heat source inlet end of the low-temperature heat source heater, and the heat source outlet end of the low-temperature heat source heater is connected to the inlet of the heat recovery system; The return water inlet end of the heating network heater is connected to the first end of the return water network, and the return water outlet end of the heating network heater is connected to the second end of the return water network; the return water inlet end of the low-temperature heat source heater is connected to the third end of the return water network, and the return water outlet end of the low-temperature heat source heater is connected to the fourth end of the return water network.

7. A method for anti-corrosion of a drain pipe, applied to the anti-corrosion device of any one of claims 1 to 5, characterized in that: include: Setting the oxygen output flow rate of the oxygen supply unit to a target preset value; Obtaining a set target dissolved oxygen value in the drain pipe anti-corrosion device; Obtaining drainage parameters in the drainage pipeline; Obtaining a target flow rate of an oxygen-enriched water metering pump in a drainage pipeline anti-corrosion device according to the set target dissolved oxygen value and the drainage parameter; The opening degree of the oxygen-enriched water metering pump is controlled according to the target flow rate of the oxygen-enriched water metering pump.

8. The method for anti-corrosion of drain pipes according to claim 7, characterized in that: The obtaining of the drainage parameters in the drainage pipeline comprises: Obtain the dissolved oxygen meter parameter signal at the end of the heating network heater drain system and the flow parameter signal of the heating network heater drain pump.

9. The method for anti-corrosion of drain pipes according to claim 8, characterized in that: The step of obtaining the target flow rate of the oxygen-enriched water metering pump in the drainage pipeline anti-corrosion device according to the set target dissolved oxygen value and the drainage parameter comprises: The set target dissolved oxygen value and the drain parameter are input into the oxygenation control model, and the output result of the oxygenation control model is the target flow rate of the oxygen-enriched water metering pump in the drain pipe anti-corrosion device; The expression of the oxygenation control model includes: <h2 style=";text-align:left;direction:ltr">Q2 = (K1(M2-M1)+K2M1e<h2 style=";text-align:left;direction:ltr"> (M2-M1) <h2 style=";text-align:left;direction:ltr"> Q1×10<h2 style=";text-align:left;direction:ltr"> -3 <h2 style=";text-align:left;direction:ltr"> ; Among them, Q2 is the flow value of the oxygen-enriched water metering pump, K1 is the proportional coefficient, M2 is the parameter value of the dissolved oxygen meter at the end of the heat network heater drain system, M1 is the target dissolved oxygen value set by the drain pipe anti-corrosion device, K2 is the constraint coefficient, and Q1 is the flow value of the heat network heater drain pump.

10. The method for anti-corrosion of drain pipe according to claim 7, characterized in that: After controlling the opening degree of the oxygen-enriched water metering pump according to the target flow rate of the oxygen-enriched water metering pump, the method further includes: The oxygen content value or steam hydrogen conductivity value of the water drain from the heating network heater is obtained, and when the oxygen content value or steam hydrogen conductivity value of the water drain from the heating network heater is greater than a preset threshold value, the oxygen-enriched water metering pump is controlled to be closed.

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