Test device and method for the effect of scaling rate on boiler heat exchange tubes

Abstract

The invention discloses a test device for the scaling rate of a boiler heat exchange tube, comprising a deoxygenated water tank, a cooling component, a heat exchanger, an electric heater, a dosing component, a water-cooled wall simulation component, a desalted water preparation component, and a sampling component connected by pipelines; the deoxygenated water tank is sequentially connected to the cooling component, the heat exchanger, the electric heater, and the water-cooled wall simulation component, the dosing component is connected to the dosing pipeline, the hot end of the water-cooled wall simulation component is connected to the heat exchanger, the water after heat exchange by the heat exchanger is connected to the deoxygenated water tank through a pipeline, the desalted water preparation component is connected to the deoxygenated water tank, and the sampling component is connected to the water outlet end of the heat exchanger, the water inlet end and the water outlet end of the water-cooled wall simulation component; the dosing component comprises at least two dissolving boxes, and the water-cooled wall simulation component comprises a test tube sample and a heating mechanism. A test method is also disclosed. The invention has the following beneficial effects: the test device is simple, the test parameters can be adjusted quickly, the disassembly and assembly are simple, and the test result evaluation is convenient.

Description

Technical Field

[0001] The invention relates to a chemical field system of a thermal power plant, and in particular to a test device and method for the influence of heat flux of a boiler heat exchange tube and water working conditions on scaling rate. Background Art

[0002] The thermal system of a thermal power generating unit can be divided into an all-iron system and a copper system according to the metal material. Currently, the units in service and newly built are basically all-iron systems, that is, the main metal materials of the thermal cycle system are carbon steel and stainless steel, and do not contain copper and copper alloys. During the operation and standby of the unit, the metal material will inevitably suffer from corrosion damage, resulting in iron impurities in the water vapor. During the migration of iron in the water vapor circulation system, the iron impurities in the water vapor working fluid will cause scaling in the high-temperature area. In the water vapor system of a thermal power generating unit, scaling generally starts from the high-pressure heater of the high-pressure feed water system, and scaling occurs in the economizer, water wall and turbine blades along the water vapor process.

[0003] Through analysis and detection, it is known that the scaling components of the current generator sets are mainly iron oxides. Therefore, corrosion and material migration in the thermal system based on iron-based materials have become the main sources of scaling substances. The characteristics of iron corrosion products in the thermal system are shown in Table 1.

[0004] Table 1 Characteristics of iron corrosion products

[0005] composition color <![CDATA[Density g / cm 3 > Thermal stability <![CDATA[Fe(OH)2 1 )]]> white 3.40 <![CDATA[Decomposes into Fe3O4 and H2 at 100 °C]]> FeO black 5.4～5.73 <![CDATA[Melts at 1371 - 1424 °C and decomposes into Fe and Fe3O4 at temperatures below 570 °C]]> <![CDATA[Fe3O4]]> black 5.20 Melts at 1597℃ α-FeOOH yellow 4.20 <![CDATA[Lose water to form α-Fe2O3 at about 200 °C]]> β-FeOOH Light brown \ <![CDATA[It loses water to form α-Fe2O3 at about 230 °C]]> γ-FeOOH orange 3.97 <![CDATA[Transforms into α-Fe2O3 at approximately 200 °C]]> <![CDATA[γ-Fe2O3]]> brown 4.88 <![CDATA[Transforms into α-Fe2O3 at temperatures above 250 °C]]> <![CDATA[α-Fe2O3]]> Brick Red 5.25 <![CDATA[Decompose into Fe3O4 at 1457 °C under 0.098 MPa]]>

[0006] Note: 1) Fe(OH)2 is unstable in an oxygen environment and can transform into γ-FeOOH, α-FeOOH or Fe3O4 at room temperature.

[0007] As can be seen from the above table, the corrosion products of iron that can stably exist during the operation of the thermal system are mainly Fe3O4 and α-Fe2O3. FeOOH is the main product of oxygen corrosion during the shutdown of the unit. After the unit is in operation, it will migrate to the higher temperature feedwater system and water-cooled wall system and will also be transformed into stable α-Fe2O3. The formation of Fe3O4 and α-Fe2O3 is related to temperature and water conditions. Among them, Fe3O4 is widely present in the water-steam system and can be generated under reducing feedwater conditions and high-temperature steam systems. α-Fe2O3 is more widely present under oxidizing feedwater conditions.

[0008] The feed water conditions of the generator set can be divided into fully volatile water conditions and oxidizing water conditions according to different dosing treatment methods. Among them, the fully volatile treatment can be divided into fully volatile reducing water conditions and fully volatile weakly oxidizing water conditions. The main differences between the three water conditions are shown in Table 2.

[0009] Table 2 Differences in different water supply conditions

[0010] Water supply conditions Types of water dosing Feed water oxygen content, μg / L Feed water oxidation-reduction potential, mV Fully volatile reducing water conditions Ammonia and hydrazine ≤7 -300～-350 Fully volatile weakly oxidized water conditions ammonia ≤10 ≈0 Oxidizing water conditions Ammonia and oxygen 10～150 +100～+150

[0011] Different feedwater conditions will have a significant impact on the morphology and corrosion process of iron in the working fluid. For large thermal power generating units, the main type of feedwater corrosion is flow-accelerated corrosion (FAC), which is accelerated corrosion occurring in the turbulent zone under a reducing environment. It not only causes corrosion damage to thermal equipment, but is also the fundamental process for the migration of corrosion products in the water-steam system. Flow-accelerated corrosion mainly includes four steps:

[0012] Carbon steel material corrodes to generate ferrous ions, some of which are oxidized on-site to ferroferric oxide.

[0013] Fe+2H2O→Fe2++2OH-+H2

[0014] 3Fe+4H2O→Fe3O4+4H2

[0015] Some of the newly generated ferrous ions diffuse through the porous oxide layer, while some of the newly generated hydrogen penetrates into the interior of the carbon steel.

[0016] Dissolution and reduction of the outer layer of ferroferric oxide.

[0017]

[0018] The dissolved iron ions migrate into the bulk water while hydrogen gas permeates through the steel into the air.

[0019] Under reducing conditions, the corrosion product of iron is mainly ferroferric oxide, with coarse grains (5-8μm), large inter-grain gaps, and loose bite, resulting in large fluid resistance and poor corrosion resistance of the oxide film on the metal surface, which causes obvious corrosion in the water supply system. If oxygen is added to the water supply, the redox potential of the water supply will increase from -300mV to +100mV. At this time, the oxide produced on the metal surface is mainly ferric oxide, with a grain size of less than 5μm, small inter-grain gaps, and tight bite. This oxide film has small fluid resistance and good corrosion resistance, which can effectively inhibit the corrosion of the water supply system, thereby reducing the iron content of the water supply system and also reducing the scaling rate of the water-cooled wall.

[0020] Among the many factors affecting water wall scaling, the most direct factor, in addition to the iron content in the feed water entering the water wall, is the water wall heat flux (heat flux (Heat Flux, Thermal Flux) is a vector, also known as heat flux density, with directionality, its magnitude is equal to the heat flowing through a unit area per unit time along this direction, the direction is along the normal direction of the isothermal surface, and it points from high temperature to low temperature). Due to the high temperature of the flame in the water-cooled furnace, it is not easy to install temperature measuring points. Therefore, the influence of heat flux in the furnace tube on the scaling rate is usually calculated based on empirical formulas, for example:

[0021]

[0022] Among them: A Fe —The formation rate of iron oxide scale, g / (m 2 h)

[0023] —Iron content in boiler water, μg / L

[0024] q—local heat flux of the furnace tube, kW / m 2

[0025] K Fe —Proportional coefficient, the laboratory value is 5.7×10 -10 ; The boiler test value is 8.3×10 -10 .

[0026] For example, application number: 201610424709.3 discloses a method for analyzing the type and cause of scaling on the water-cooled wall of a boiler of a thermal power generating unit. The method comprehensively diagnoses the type and cause of scaling on the water-cooled wall of the boiler by combining macroscopic inspection, metallographic inspection and X-ray diffraction phase analysis. Specifically, the method includes the following steps:

[0027] (1) Cut the boiler water wall tube sample and observe the scaling condition;

[0028] (2) The cut boiler water-cooled wall tube samples are peeled, cut in half, and then chemically cleaned to observe the morphology of the metal matrix of the boiler water-cooled wall tube samples after cleaning;

[0029] (3) Conduct metallographic examination on boiler water wall tube samples before and after chemical cleaning;

[0030] (4) X-ray diffraction phase analysis of the scale on the boiler water wall tube sample surface;

[0031] (5) Determine the type and cause of scaling by observing and analyzing the results of steps (1) to (4).

[0032] However, since the operation mode of the generator set is relatively fixed, the test of different water conditions and heat fluxes on the generator set to determine the water wall scaling rate has the following shortcomings:

[0033] (1) The operating parameters of the generator set are relatively fixed. For example, the feed water condition is relatively fixed, and the boiler water wall heat flux is affected by the unit's power generation load. It is difficult to conduct experiments to adjust the influencing parameters.

[0034] (2) The test cycle for the effect of water conditions and heat flux on the scaling rate of the water-cooled wall is relatively long, and the water-cooled wall tube cutting work cannot be carried out in real time during the operation of the generator set, making it difficult to effectively evaluate the test results;

[0035] (3) Conducting tests on the effects of water conditions and heat flux on the scaling rate of the water-cooled wall on the generator set may increase the scaling rate of the water-cooled wall and increase the risk of corrosion, causing harm to the generator set.

[0036] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0037] The technical problem to be solved by the present invention is: how to solve the problems in the prior art of conducting a test on the influence of water conditions and heat flux on the scaling rate of the water-cooled wall when a generator set is in operation, the test is difficult, effective data cannot be obtained, and it is easy to cause harm to the unit. A test device and method specifically for testing the influence of water conditions and heat flux on the scaling rate of the water-cooled wall of a generator set is provided.

[0038] The present invention solves the above technical problems through the following technical means:

[0039] The scaling rate influence test device of the boiler heat exchange tube includes a deaeration water tank, a cooling component, a heat exchanger, an electric heater, a dosing component, a water-cooled wall simulation component, a desalted water preparation component, and a sampling component connected by pipelines;

[0040] The deoxygenated water tank is connected to the cooling component, the cooling component is connected to the heat exchanger, the heat exchanger is connected to the electric heater, the electric heater is connected to the water-cooled wall simulation component through a dosing pipeline, the dosing component is connected to the dosing pipeline, the hot end of the water-cooled wall simulation component is connected to the heat exchanger, the water after heat exchange in the heat exchanger is connected to the deoxygenated water tank through a pipeline, the desalted water preparation component is connected to the deoxygenated water tank, and the sampling component is connected to the water outlet end of the heat exchanger, the water inlet end and the water outlet end of the water-cooled wall simulation component;

[0041] The dosing component includes at least two dissolving boxes, the water-cooled wall simulation component includes a test tube sample and a heating mechanism for heating the test tube sample.

[0042] This device can effectively simulate the effects of multiple parameters such as heat flux of boiler heat exchange tubes, feed water conditions, and iron impurity content and form on scaling rate during the operation of the generator set. The test device is relatively simple and can quickly adjust the test parameters. Compared with the pipe cutting operation of the generator set, the test pipe sample is easy to disassemble and assemble, which is convenient for the evaluation of the test results.

[0043] Preferably, a steam inlet valve is provided at the top of the deoxygenated water tank, and a drain valve and an outlet valve are provided at the bottom, the outlet valve is connected to the pipe connecting the deoxygenated water tank and the cooling component, the desalted water preparation component is connected to the top of the deoxygenated water tank through a third pipe, and the heat exchanger is connected to the top of the deoxygenated water tank through a first pipe.

[0044] Preferably, the cooling component includes a cooling water inlet valve and a drain outlet for cooling water to enter, and the water outlet of the cooling component is connected to the heat exchanger through a second pipe, and a water delivery pump, a flow regulating valve, and a first pressure gauge are installed on the second pipe.

[0045] Preferably, the heat exchanger comprises a primary heat exchanger and a secondary heat exchanger connected in series.

[0046] Preferably, the electric heater comprises a primary electric heater and a secondary electric heater connected in series.

[0047] Preferably, the dosing component also includes at least two dosing pumps, the outlet of each dissolving drug box is connected to the dosing pump, at least two dissolving drug boxes are connected in parallel to the drug outlet pipeline, the drug outlet pipeline is connected to the dosing pipeline, and the drug outlet pipeline is provided with a dosing outlet pressure gauge and a dosing outlet valve.

[0048] Preferably, the water-cooled wall simulation component also includes an inlet pressure gauge and an outlet pressure gauge. After the dosing component adds medicine, the solution enters the test tube sample through the pipeline. The inlet end and outlet end of the test tube sample are respectively provided with an inlet pressure gauge and an outlet pressure gauge.

[0049] Preferably, the desalted water preparation component includes a cation exchanger, an anion exchanger, and a mixed ion exchanger connected in series in sequence, the cation exchanger is provided with a tap water inlet valve for controlling the entry of tap water, and the outlet of the mixed ion exchanger is connected to the top of the deoxygenated water tank through a third pipe.

[0050] Preferably, the sampling assembly includes a sampling shell, a fourth pipe, a fifth pipe, and a sixth pipe. A cooling water inlet pipe is provided at the top of the sampling shell. The starting end of the fourth pipe is connected to the water outlet of the heat exchanger and passes through the sampling shell. The starting end of the fifth pipe is connected to the inlet end of the water-cooled wall simulation assembly and passes through the sampling shell. The starting end of the sixth pipe is connected to the outlet end of the water-cooled wall simulation assembly and passes through the sampling shell. Sampling valves are provided at the ends of the fourth pipe, the fifth pipe, and the sixth pipe.

[0051] The present invention also adopts the above-mentioned method of the scaling rate impact test device of the boiler heat exchange tube, comprising the following steps:

[0052] SO1: After preparing desalted water with conductivity that meets the requirements, inject desalted water into the deoxygenated water tank; after the water level in the deoxygenated water tank meets the requirements, inject water into the pipes in the entire system. During this process, the desalted water preparation component operates;

[0053] S02: Sampling the water outlet of the heater, the water inlet and the water outlet of the water-cooled wall simulation component through the sampling component, and detecting the conductivity of the three sampling points. If the conductivity does not meet the requirements, open the deoxygenated water tank to discharge sewage until the conductivity of the three sampling points meets the requirements;

[0054] SO3: Turn on the dosing component, configure ammonia solution / ammonia + hydrazine solution in one of the dissolving boxes, adjust the pH value and hydrazine value in the system water sample until the pH value and hydrazine value of the three sampling points are qualified, and then stop dosing;

[0055] S04: Turn on the cooler and the electric heater, start the heating mechanism of the water wall simulation component to heat the system water sample, configure an iron solution in one of the dissolving boxes, and turn on the dosing component to adjust the iron content in the system water sample. When the iron content indicators of the three sampling points are qualified, stop dosing;

[0056] S05: When the iron content, pH value and hydrazine value in the water in the device are qualified, the test starts timing, and the oxygen content, iron content, pH / pH+hydrazine in the water sample are tested regularly. When the iron content and pH / pH+hydrazine are about to reach the lower limit of the control value, the iron content and pH / pH+hydrazine are adjusted to the control value range through the pressurizing component; when the test time is completed, the electric heater, water-cooled wall simulation component, and heat exchanger are turned off, and the water in the sampling component is discharged;

[0057] S06: Cut the test tube sample on the water-cooled wall simulation assembly, detect the amount of scaling per unit area on the inner wall of the test tube sample, and calculate the scaling rate of the test tube sample under the test conditions, heat flux and water conditions in combination with the test time; by conducting orthogonal tests under different heat flux and water conditions, the scaling rate law of the heat exchange tube is obtained.

[0058] Preferably, the water operating conditions in step S06 include fully volatile reducing water conditions, fully volatile weakly oxidizing water conditions and oxidizing water conditions.

[0059] Preferably, when the working condition is fully volatile reducing water, one of the solvent boxes is configured with ammonia and hydrazine solution, and one of the solvent boxes is configured with ferrosoferric oxide;

[0060] When it is a fully volatile weakly oxidized water working condition, one of the dissolving tanks is equipped with ammonia solution, and one of the dissolving tanks is equipped with ferroferric oxide and ferric oxide solution; when the detected dissolved oxygen is greater than the set value, saturated steam is introduced into the deoxygenation water tank;

[0061] When it is an oxidizing water condition, an ammonia solution is placed in one of the solvent boxes, and a ferric oxide solution is placed in another solvent box, and air is blown into the ferric oxide solution to make the dissolved oxygen concentration in the solution reach a saturated state; and saturated steam is introduced into the deoxygenation water tank;

[0062] The saturation concentration of dissolved oxygen in water is:

[0063]

[0064] Among them, P is the measured atmospheric pressure; P0 is the standard atmospheric pressure; T is the water temperature; DO is the dissolved oxygen concentration;

[0065] The actual value of dissolved oxygen in water detected by the sampling component is DO0, so the dosage of the dissolving box configured with ferric oxide solution is:

[0066]

[0067]

[0068] Where DO is the dissolved oxygen concentration; DO0 is the actual value of dissolved oxygen; Q is the water flow rate in the test device; V 10 To control the dosage when the dissolved oxygen concentration in water is 10μg / L; V 50 To control the dosage when the dissolved oxygen concentration in water is 50μg / L; the dosage should be controlled at V 10 -V 50 between;

[0069] In the fully volatile reducing water condition, the fully volatile weakly oxidizing water condition, and the oxidizing water condition, the heat flux calculation formula in step S06 is:

[0070] q=U·I / S 内 1000

[0071] Where, q is the heat flux; U is the voltage of the heating mechanism; I is the current of the heating mechanism; S 内 is the inner surface area of ​​the tested tube sample;

[0072] The specific steps of step S06 are: after the test, cut the test tube sample, use 5% hydrochloric acid solution with corrosion inhibitor to clean the scaling product, and the scaling rate calculation formula is:

[0073]

[0074] Among them, m 前 is the mass of the test tube sample before cleaning, m 后 A is the quality of the test tube sample after cleaning, Fe is the scaling rate.

[0075] The advantages of the present invention are:

[0076] (1) This device can effectively simulate the effects of multiple parameters such as heat flux of boiler heat exchange tubes, feed water conditions, and iron impurity content and form on scaling rate during the operation of the generator set. The test device is relatively simple and can quickly adjust the test parameters. Compared with the pipe cutting operation of the generator set, the test pipe sample is easy to disassemble and assemble, which is convenient for evaluating the test results.

[0077] (2) The device is equipped with at least two dosing units, which can adjust the water supply conditions and iron content separately without interfering with each other, and the parameters can be adjusted flexibly.

[0078] (3) The device uses the water-cooled wall to simulate the high temperature water sample behind the assembly to preheat the system water sample, thereby improving the heat exchange efficiency and reducing the energy consumption of the subsequent electric heater.

[0079] (4) The output power of the electric heater is adjustable, which can control the water sample temperature and simulate the heat flux of the water-cooled wall. The test heat flux range is wide.

[0080] (5) The device is equipped with sampling points at the heat exchanger outlet, water wall simulation component inlet and water wall simulation component outlet, which can monitor parameters such as pH, redox potential and iron content in the test device through real-time sampling and analysis, facilitating the operation adjustment of the dosing system. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 It is a structural schematic diagram of a scaling rate influence test device for boiler heat exchange tubes of the present invention;

[0082] Figure 2 is a flow chart of a test method for the scaling rate influence of boiler heat exchange tubes in an embodiment of the present invention;

[0083] Numbers in the figure:

[0084] 100, deaerator tank; 101, steam inlet valve; 102, drain valve; 103, outlet valve; 104, inlet valve; 105, flow meter;

[0085] 200, cooling assembly; 201, first cooling water inlet valve; 203, second pipeline; 202, sewage outlet; 204, water delivery pump; 205, flow regulating valve; 206, first pressure gauge;

[0086] 300, heat exchanger; 301, first pipeline; 302, primary heat exchanger; 303, secondary heat exchanger;

[0087] 400, electric heater; 401, primary electric heater; 402, secondary electric heater; 403, second pressure gauge;

[0088] 500, dosing assembly; 501, dosing pipeline; 502, first dissolving box; 503, second dissolving box; 504, first dosing pump; 505, second dosing pump; 506, dosing outlet pressure gauge; 507, dosing outlet valve;

[0089] 600, water-cooled wall simulation component; 601, seventh pipeline; 602, test tube sample; 603, heating mechanism; 604, component inlet pressure gauge; 605, component outlet pressure gauge;

[0090] 700, demineralized water preparation component; 701, third pipeline; 702, cation exchanger; 703, anion exchanger; 704, mixed ion exchanger; 705, tap water inlet valve; 706, sampling and discharge valve; 707, outlet valve;

[0091] 800, sampling assembly; 801, second cooling water inlet valve; 802, fourth pipeline; 803, fifth pipeline; 804, sixth pipeline; 805, sampling valve after heater; 806, inlet sampling valve of water-cooled wall simulation device; 807, outlet sampling valve of water-cooled wall simulation device; DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are 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 are within the scope of protection of the present invention.

[0093] Embodiment 1:

[0094] like Figure 1 As shown, the scaling rate impact test device of the boiler heat exchange tube includes a deoxygenated water tank 100, a cooling assembly 200, a heat exchanger 300, an electric heater 400, a dosing assembly 500, a water-cooled wall simulation assembly 600, a desalted water preparation assembly 700, and a sampling assembly 800 connected by pipelines;

[0095] The deoxygenated water tank 100 is connected to the cooling component 200, the cooling component 200 is connected to the heat exchanger 300, the heat exchanger 300 is connected to the electric heater 400, the electric heater 400 is connected to the water-cooled wall simulation component 600 through the dosing pipe 501, the dosing component 500 is connected to the dosing pipe 501, the hot end of the water-cooled wall simulation component 600 is connected to the heat exchanger 300 through the seventh pipe 601, the water after heat exchange in the heat exchanger 300 is connected to the deoxygenated water tank 100 through the first pipe 301, the desalted water preparation component 700 is connected to the deoxygenated water tank 100, and the sampling component 800 is connected to the water outlet end of the heat exchanger 300, the water inlet end and the water outlet end of the water-cooled wall simulation component 600;

[0096] Specifically, the top of the deoxygenated water tank 100 is provided with a steam inlet valve 101, through which saturated steam can be introduced to thermally deoxygenate the water entering the deoxygenated water tank 100. By adjusting the opening of the steam inlet valve 101, the amount of steam introduced can be adjusted to adjust the residual oxygen concentration of the water in the deoxygenated water tank 100 after deoxygenation. The bottom of the deoxygenated water tank 100 is provided with a drain valve 102, which can discharge unqualified water; the bottom of the deoxygenated water tank 100 is also provided with an outlet valve 103, and the outlet valve 103 is connected to the pipeline connecting the deoxygenated water tank 100 and the cooling component 200; the desalted water preparation component 700 is connected to the top of the deoxygenated water tank 100 through the third pipeline 701, and the heat exchanger 300 is connected to the top of the deoxygenated water tank 100 through the first pipeline 301.

[0097] One side of the cooling assembly 200 has a pipeline for cooling water to enter, and a first cooling water inlet valve 201 is provided on the pipeline. A sewage outlet 202 is provided at the bottom of the cooling assembly 200. The water outlet of the cooling assembly 200 is connected to the heat exchanger 300 through a second pipeline 203. A delivery water pump 204, a flow regulating valve 205, and a first pressure gauge 206 are installed on the second pipeline 203. Cooling water is introduced through the first cooling water inlet valve 201. The cooling water source is tap water, and the cooling water is discharged through the sewage outlet 202. The cooling assembly 200 can cool the outlet water of the deoxygenated water tank 100 to below 60°C to meet the requirements of the delivery water pump 204 for the inlet water temperature. The flow regulating valve 205 can adjust the water volume in the test device system. A first pressure gauge 206 is provided after the flow regulating valve 205 to monitor the outlet pressure of the delivery water pump 204.

[0098] The heat exchanger 300 is arranged in two stages in series, including a primary heat exchanger 302 and a secondary heat exchanger 303. The primary heat exchanger 302 and the secondary heat exchanger 303 are both divided into a cold end and a hot end. The cold end is the low-temperature water flow channel at the outlet of the delivery water pump 204, and the hot end is the high-temperature water flow channel at the outlet of the water-cooled wall simulation component 600. Both the primary heat exchanger 302 and the secondary heat exchanger 303 are tubular heat exchangers. The outlet of the water-cooled wall simulation component 600 can be used to pass high-temperature water into the heat exchanger 300 through the seventh pipe 601 to preheat the low-temperature water at the outlet of the delivery water pump 204. While reducing the outlet water temperature of the water-cooled wall simulation component 600 to meet the water inlet temperature requirements of the deoxygenation water tank 100, it can also increase the outlet water temperature of the delivery water pump 204 and reduce the output power of the subsequent electric heater 400.

[0099] The electric heater 400 is connected in two stages in series, including a primary electric heater 401 and a secondary electric heater 402. The electric heater 400 heats the outlet water of the heat exchanger 300. The heated water enters the water-cooled wall simulation component 600 through the dosing pipe 501. The water temperature can be raised to 270°C at most. Before entering the electric heater 400, it also includes a second pressure gauge 403.

[0100] The dosing assembly 500 includes at least two dissolving medicine boxes and at least two dosing pumps. In this embodiment, it includes a first dissolving medicine box 502, a second dissolving medicine box 503, a first dosing pump 504, and a second dosing pump 505. The outlet of the first dissolving medicine box 502 is connected to the first dosing pump 504, and the outlet of the second dissolving medicine box 503 is connected to the second dosing pump 505. A dissolving medicine box outlet valve is provided between the dissolving medicine box and the dosing pump; the first dissolving medicine box 502 and the second dissolving medicine box 503 are connected in parallel to the medicine outlet pipeline, and the medicine outlet pipeline is connected to the dosing pipeline 501. The medicine outlet pipeline is provided with a dosing outlet pressure gauge 506 and a dosing outlet valve 507. In order to accurately adjust the pH, redox potential and iron content in the test water; the device is provided with at least two dosing units, which can adjust the water supply water condition and iron content respectively, without interfering with each other, and the parameters can be adjusted flexibly.

[0101] The water-cooled wall simulation component 600 includes a water-cooled wall simulation shell, a test tube sample 602, and a heating mechanism 603 for heating the test tube sample 602. The test tube sample 602 is built inside the water-cooled wall simulation shell. The water-cooled wall simulation component 600 also includes an inlet pressure gauge 604 and an outlet pressure gauge 605. After the dosing component 500 adds drugs, the solution enters the test tube sample 602 through the dosing pipeline 501. The inlet end and the outlet end of the test tube sample 602 are respectively provided with an inlet pressure gauge 604 and an outlet pressure gauge 605. The test tube sample 602 can be welded in the water-cooled wall simulation shell. The material of the tube sample is SA-213T12 or 15CrMo low alloy steel. The electric heating power of the heating mechanism 603 is adjustable, and the scaling rate test can be carried out under different heat flux conditions.

[0102] The water outlet of the water-cooled wall simulation component 600 passes through the first-stage heat exchanger 302 and the second-stage heat exchanger 303 in sequence through the seventh pipeline 601, and exchanges heat with the low-temperature water at the outlet of the delivery water pump 204. A flow meter 105 and an inlet valve 104 are provided at one end of the seventh pipeline 601 close to the deoxygenated water tank 100, and the end of the seventh pipeline 601 enters the top of the deoxygenated water tank 100. The water sample with a higher temperature after the water-cooled wall simulation component 600 is used to preheat the system water sample, thereby improving the heat exchange efficiency and reducing the energy consumption of the subsequent electric heater.

[0103] The deionized water preparation component 700 includes a cation exchanger 702, an anion exchanger 703, and a mixed ion exchanger 704 connected in series in sequence. The cation exchanger 702 is provided with a tap water inlet valve 705 for controlling the entry of tap water. The outlet of the mixed ion exchanger 704 is connected to the top of the deoxygenated water tank 100 through a third pipe 701. The third pipe 701 has a branch at the outlet of the mixed ion exchanger 704, and a sampling and discharge valve 706 is provided on the branch; the third pipe 701 is provided with a water outlet valve 707.

[0104] The cation exchanger 702 is filled with cation exchange resin, the anion exchanger 703 is filled with anion exchange resin, and the mixed ion exchanger 704 is filled with cation and anion exchange resins and fully mixed. The inlet water of the equipment is tap water, and the preparation of demineralized water can ensure that the conductivity is ≤0.15μS / cm.

[0105] The sampling assembly 800 includes a second cooling water inlet valve 801, a fourth pipe 802, a fifth pipe 803, and a sixth pipe 804. A cooling water inlet pipe is provided at the top of the sampling shell, and a second cooling water inlet valve 801 is provided on the cooling water inlet pipe. The starting end of the fourth pipe 802 is connected to the outlet end of the heat exchanger 300 and passes through the sampling shell. The starting end of the fifth pipe 803 is connected to the inlet end of the water-cooled wall simulation assembly 600 and passes through the sampling shell. The starting end of the sixth pipe 804 is connected to the outlet end of the water-cooled wall simulation assembly 600 and passes through the sampling shell. Connected to the outlet end of the water-cooled wall simulation component 600 and passing through the sampling shell, the ends of the fourth pipeline 802, the fifth pipeline 803, and the sixth pipeline 804 are all provided with sampling valves. Specifically, the end of the fourth pipeline 802 is the sampling valve 805 after the heater, the end of the fifth pipeline 803 is the inlet sampling valve 806 of the water-cooled wall simulation device, and the end of the sixth pipeline 804 is the outlet sampling valve 807 of the water-cooled wall simulation device. After the water from the test device is cooled by the sampling component 800, the water sample temperature can be reduced to 25°C±2°C.

[0106] The device in this embodiment can effectively simulate the effect of multiple parameter changes such as heat flux of boiler heat exchange tubes, feed water conditions, and iron impurity content and morphology on scaling rate during the operation of the generator set. The test device is relatively simple and can quickly adjust the test parameters. Compared with the generator set pipe cutting operation, the test pipe sample 602 is easy to disassemble and assemble, which is convenient for evaluating the test results.

[0107] Embodiment 2:

[0108] This embodiment also adopts the method of the above-mentioned boiler heat exchange tube scaling rate impact test device, including the following steps:

[0109] Step SO1: First, tap water is introduced into the desalted water preparation component 700 through the tap water inlet valve 705 to prepare desalted water, and the conductivity of the water outlet is detected at the sampling and discharge valve 706. When the conductivity of the desalted water does not meet the requirement of ≤0.15μS / cm, continuous discharge is performed. When the requirement is met, the outlet valve 707 is opened to inject water into the deoxygenated water tank 100.

[0110] When the water level of the deoxygenated water tank 100 reaches a high level, the outlet valve 103 and the inlet valve 104 of the deoxygenated water tank 100 are opened, the delivery water pump 204 is started, and the flow regulating valve 205 at the outlet of the delivery water pump 204 is slowly opened to prevent the current of the delivery water pump 204 from being overloaded. The system pipeline is filled with water through the delivery water pump 204, and the desalted water preparation component 700 is operated during the filling process to control the water level of the deoxygenated water tank 100 to operate at a high level.

[0111] Step S02: When the test device is full of water and a circulation is established, the sampling valve 805 after the heater, the sampling valve 806 at the inlet of the water-cooled wall simulation device, and the sampling valve 807 at the outlet of the water-cooled wall simulation device are opened respectively to detect the conductivity of the water sample in the test device respectively. If the conductivity is greater than 0.15 μS / cm, the drain valve 102 of the deoxygenated water tank 100 is opened to flush and drain the water through the drain port of the deoxygenated water tank 100 until the conductivity of the water samples at the three sampling points is less than or equal to 0.15 μS / cm.

[0112] When the conductivity of the system water sample is qualified, close the tap water inlet valve 705 and the outlet valve 707 of the deionized water preparation component 700. Adjust the water level of the deoxygenated water tank 100 to a low level and close the drain valve 102.

[0113] Step SO3: prepare ammonia solution / ammonia + hydrazine solution in the first solvent box 502, open the outlet valve of the solvent box, open the dosing outlet valve 507 and other valves on the drug outlet pipeline, start the first dosing pump 504, adjust the pH value / pH value + hydrazine content in the system water sample, and stop the first dosing pump 504 after the sampling valve 805 after the heater, the inlet sampling valve 806 of the water-cooled wall simulation device and the outlet sampling valve 807 of the water-cooled wall simulation device detect that the pH value / pH value + hydrazine content index is qualified.

[0114] Step S04: Open the first cooling water inlet valve 201 of the cooling assembly 200 and the second cooling water inlet valve 801 of the sampling assembly 800 respectively. At the same time, start the electric heater 400, start the heating mechanism 603 of the water-cooled wall simulation assembly 600, heat the system water sample, and adjust the heat flux of the test tube sample 602 welded on the water-cooled wall simulation assembly 600 to the experimental value.

[0115] An iron solution is prepared in the second solvent box 503, the outlet valve of the solvent box is opened, the second dosing pump 505 is started, and the iron content in the system water sample is adjusted. When the iron content index detected by the sampling valve 805 after the heater, the inlet sampling valve 806 of the water-cooled wall simulation device and the outlet sampling valve 807 of the water-cooled wall simulation device is qualified, the second dosing pump 505 can be stopped.

[0116] Step S05: When the iron content, pH value / pH value+hydrazine content in the water in the device are qualified, the test starts timing. During the test, when the water level in the deoxygenated water tank 100 is low, the tap water inlet valve 705 and the outlet valve 707 of the desalted water preparation component 700 need to be opened to replenish water to the deoxygenated water tank 100 to a high level;

[0117] The oxygen content, iron content, pH value / pH value+hydrazine content in the water sample are regularly tested through the sampling valve 805 after the heater, the sampling valve 806 at the inlet of the water-cooled wall simulation device, and the sampling valve 807 at the outlet of the water-cooled wall simulation device. When the iron content and pH / pH+hydrazine are about to reach the lower limit of the control value, the first dosing pump 504 and the second dosing pump 505 can be turned on respectively to adjust the iron content and pH / pH+hydrazine to the control value range.

[0118] When the test time is completed, turn off the primary electric heater 401 and the secondary electric heater 402, and turn off the heating mechanism 603 of the water-cooled wall simulation component 600. When the water temperature drops below 40°C, stop the water delivery pump 204. Close the first cooling water inlet valve 201 of the cooling component 200, close the second cooling water inlet valve 801 of the sampling component 800, and discharge the water in the device through the post-heater sampling valve 805, the water-cooled wall simulation device inlet sampling valve 806, and the water-cooled wall simulation device outlet sampling valve 807.

[0119] Step S06: Cut the test tube sample 602 on the water-cooled wall simulation assembly 600, detect the amount of scaling per unit area of ​​the inner wall of the sample, and calculate the scaling rate of the heat flux and water working conditions of the test tube sample 602 under the test conditions in combination with the test time. By conducting orthogonal tests under different heat flux and water working conditions, the scaling rate law of the heat exchange tube can be obtained.

[0120] Embodiment three:

[0121] See also Figure 2As shown, after the test device is filled with water and a circulation is established in the second embodiment, the sampling valve 805 after the heater, the sampling valve 806 at the inlet of the water-cooled wall simulation device, and the sampling valve 807 at the outlet of the water-cooled wall simulation device are opened, and the conductivity of the water samples at the three sampling points is detected to be ≤0.15μS / cm; when the conductivity of the system water sample is qualified, the tap water inlet valve 705 and the outlet valve 707 of the desalted water preparation component 700 are closed. Adjust the water level of the deoxygenated water tank to a low level and close the drain valve 102.

[0122] The water operating conditions in step S06 include fully volatile reducing water conditions, fully volatile weakly oxidizing water conditions and oxidizing water conditions.

[0123] (1) When it is a fully volatile reducing water condition,

[0124] Ammonia and hydrazine solutions are arranged in the first solvent box 502, wherein the addition of ammonia can make the pH of water alkaline, and hydrazine can make water reductive. Ferroferric oxide solution is arranged in the second solvent box 503, and during the test, the pH, hydrazine, dissolved oxygen and iron content in the water can be sampled and tested through the inlet sampling valve 806 of the water-cooled wall simulation device, and the pH is controlled to be 9.3±0.1, hydrazine≤30μg / L, dissolved oxygen≤7μg / L, and iron content is 5-10μg / L.

[0125] When the fully volatile reducing water working condition is adopted, the steam inlet valve 101 of the deoxygenation water tank 100 needs to be opened to introduce saturated steam to thermally deoxygenate the water in the deoxygenation water tank 100 .

[0126] During the test, the test tube sample 602 is heated by the heating mechanism 603, and the heat is transferred to the test tube sample 602 through the heating wire. The heating current I and voltage U of the heating mechanism 603 are measured using an ammeter and a voltmeter, respectively, and the inner surface area S of the test tube sample 602 is measured. 内 , the heat flux calculation formula is as follows:

[0127] q=U·I / S 内 ·1000 Formula 2

[0128] Where, q-heat flux, kW / m 2 ; U-voltage, V; I-current, A; S in - Internal surface area of ​​the test cell, m 2 .

[0129] The test heat fluxes were 200, 250, 300 and 350 kW / m 2 The test was carried out under the conditions of 168 hours under each heat flux condition. After each test, the test tube sample 602 was cut and the scaling product was cleaned with a 5% hydrochloric acid solution containing a corrosion inhibitor. The mass before and after cleaning was m 前 and m 后, then the scaling rate calculation formula is:

[0130]

[0131] Among them, A Fe - fouling rate, g / (m 2 h).

[0132] (2) When using fully volatile weakly oxidized water, an ammonia solution is prepared in the first solvent tank 502, wherein the addition of ammonia can make the pH of the water alkaline. The second solvent tank 503 is prepared with ferroferric oxide and ferric oxide solutions. During the test, the pH, dissolved oxygen and iron content in the water can be sampled and tested through the inlet sampling valve 806 of the water-cooled wall simulation device, and the pH is controlled to be 9.3±0.1, the dissolved oxygen ≤10μg / L, and the iron content is 5-10μg / L.

[0133] When fully volatile weakly oxidizing water is used, the steam inlet valve 101 of the deoxygenation water tank 100 is closed. When the dissolved oxygen detected at the inlet sampling valve 806 of the water-cooled wall simulation device is greater than 10 μg / L, the steam inlet valve 101 of the deoxygenation water tank 100 is opened to introduce saturated steam to thermally deoxygenate the water in the deoxygenation water tank 100 and control the dissolved oxygen in the water to be ≤10 μg / L.

[0134] During the test, the test tube sample 602 is heated by the heating mechanism 603, and the heat is transferred to the test tube sample 602 through the heating wire. The heating current I and voltage U of the heating mechanism 603 are measured using an ammeter and a voltmeter, respectively, and the inner surface area S of the test tube sample 602 is measured. The heat flux calculation formula is shown in Formula 2.

[0135] The test heat fluxes were 200, 250, 300 and 350 kW / m 2 The test was carried out under the conditions of 168 hours under each heat flux condition. After each test, the test tube sample 602 was cut and the scaling product was cleaned with a 5% hydrochloric acid solution containing a corrosion inhibitor. The mass before and after cleaning was m 前 and m 后 , the scaling rate calculation formula is shown in Formula 3.

[0136] (3) When further adopting the oxidizing water working condition, an ammonia solution is prepared in the first solvent box 502, wherein the addition of ammonia can make the pH of the water alkaline. A ferric oxide solution is prepared in the second solvent box 503, and air is blown into the ferric oxide solution to make the dissolved oxygen concentration in the solution reach a saturated state. During the test, the pH, dissolved oxygen and iron content in the water can be sampled and tested through the inlet sampling valve 806 of the water-cooled wall simulation device, and the pH is controlled to be 8.9±0.1, 10≤dissolved oxygen≤50μg / L, and the iron content is 5-10μg / L.

[0137] Ignoring the influence of ferric oxide solution, the saturated concentration of dissolved oxygen in water is:

[0138]

[0139] p-measured atmospheric pressure, hPa; p0-standard atmospheric pressure, hPa; T-water temperature, ranging from 0 to 40°C; DO-dissolved oxygen concentration, mg / L.

[0140] When using oxidizing water conditions, in order to accurately control the dissolved oxygen content in the water of the test device, it is necessary to open the steam inlet valve 101 of the deoxygenated water tank 100, pass saturated steam, and perform thermal deoxygenation on the water in the deoxygenated water tank 100. The dissolved oxygen concentration in the water after thermal deoxygenation can be sampled and tested through the sampling valve 805 after the heater. The actual value of dissolved oxygen in the tested water is DO0, and the dosage of the second dosing pump 505 is:

[0141]

[0142]

[0143] DO-dissolved oxygen concentration, mg / L; DO0-actual dissolved oxygen value, mg / L; Q-water flow rate in the test device, L / h; V 10- Dosage for controlling dissolved oxygen concentration in water to 10μg / L, L / h; V 50 -Control the dosage when the dissolved oxygen concentration in water is 50μg / L, L / h.

[0144] Then the dosage of the second dosing pump 505 (referring to the amount of ferric oxide solution containing saturated dissolved oxygen added) should be controlled at V 10 -V 50 between.

[0145] During the test, the test tube sample 602 is heated by the heating mechanism 603, and the heat is transferred to the test tube sample 602 through the heating wire. The heating current I and voltage U of the heating mechanism 603 are measured using an ammeter and a voltmeter, respectively, and the inner surface area S of the test tube sample 602 is measured. The heat flux calculation formula is shown in Formula 2.

[0146] The test heat fluxes were 200, 250, 300 and 350 kW / m 2 The test was carried out under the conditions of 168 hours under each heat flux condition. After each test, the test tube sample 602 was cut and the scaling product was cleaned with a 5% hydrochloric acid solution containing a corrosion inhibitor. The mass before and after cleaning was m 前 and m 后 , the scaling rate calculation formula is shown in Formula 3.

[0147] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The scaling rate test device for boiler heat exchange tubes is characterized by: It includes a deoxygenated water tank, a cooling component, a heat exchanger, an electric heater, a dosing component, a water-cooled wall simulation component, a desalted water preparation component, and a sampling component connected by pipelines; The deoxygenated water tank is connected to the cooling component, the cooling component is connected to the heat exchanger, the heat exchanger is connected to the electric heater, the electric heater is connected to the water-cooled wall simulation component through a dosing pipeline, the dosing component is connected to the dosing pipeline, the hot end of the water-cooled wall simulation component is connected to the heat exchanger, the water after heat exchange in the heat exchanger is connected to the deoxygenated water tank through a pipeline, the desalted water preparation component is connected to the deoxygenated water tank, and the sampling component is connected to the water outlet end of the heat exchanger, the water inlet end and the water outlet end of the water-cooled wall simulation component; The dosing assembly includes at least two drug dissolving boxes, and the water-cooled wall simulation assembly includes a test tube sample and a heating mechanism for heating the test tube sample; The dosing assembly also includes at least two dosing pumps, the outlet of each dissolving medicine box is connected to the dosing pump, at least two dissolving medicine boxes are connected in parallel to the medicine outlet pipeline, the medicine outlet pipeline is connected to the dosing pipeline, and the medicine outlet pipeline is provided with a dosing outlet pressure gauge and a dosing outlet valve; The sampling assembly includes a sampling shell, a fourth pipe, a fifth pipe, and a sixth pipe. A cooling water inlet pipe is provided at the top of the sampling shell. The starting end of the fourth pipe is connected to the water outlet of the heat exchanger and passes through the sampling shell. The starting end of the fifth pipe is connected to the inlet of the water-cooled wall simulation assembly and passes through the sampling shell. The starting end of the sixth pipe is connected to the outlet of the water-cooled wall simulation assembly and passes through the sampling shell. Sampling valves are provided at the ends of the fourth pipe, the fifth pipe, and the sixth pipe.

2. The scaling rate impact test device for boiler heat exchange tubes according to claim 1, characterized in that: A steam inlet valve is provided at the top of the deoxygenated water tank, and a drain valve and an outlet valve are provided at the bottom. The outlet valve is connected to the pipe connecting the deoxygenated water tank and the cooling component. The desalted water preparation component is connected to the top of the deoxygenated water tank through a third pipe, and the heat exchanger is connected to the top of the deoxygenated water tank through a first pipe.

3. The scaling rate test device for boiler heat exchange tubes according to claim 1, characterized in that: The cooling component includes a cooling water inlet valve and a drain port for cooling water to enter. The water outlet of the cooling component is connected to the heat exchanger through a second pipeline. A water delivery pump, a flow regulating valve, and a first pressure gauge are installed on the second pipeline.

4. The scaling rate impact test device for boiler heat exchange tubes according to claim 1, characterized in that: The heat exchanger comprises a primary heat exchanger and a secondary heat exchanger connected in series.

5. The scaling rate influence test device of boiler heat exchange tube according to claim 1, characterized in that: The electric heater comprises a primary electric heater and a secondary electric heater which are connected in series.

6. The scaling rate influence test device of boiler heat exchange tube according to claim 1, characterized in that: The water-cooled wall simulation component also includes an inlet pressure gauge and an outlet pressure gauge. After the dosing component adds medicine, the solution enters the test tube sample through the pipeline. The inlet end and outlet end of the test tube sample are respectively provided with an inlet pressure gauge and an outlet pressure gauge.

7. The scaling rate impact test device for boiler heat exchange tubes according to claim 1, characterized in that: The desalted water preparation component includes a cation exchanger, an anion exchanger, and a mixed ion exchanger connected in series in sequence. The cation exchanger is provided with a tap water inlet valve for controlling the entry of tap water. The outlet of the mixed ion exchanger is connected to the top of the deoxygenated water tank through a third pipe.

8. The method for using the boiler heat exchange tube scaling rate test device according to any one of claims 1 to 7, characterized in that: The following steps are involved: SO1: After preparing desalted water with conductivity that meets the requirements, inject desalted water into the deoxygenated water tank; after the water level in the deoxygenated water tank meets the requirements, inject water into the pipes in the entire system. During this process, the desalted water preparation component operates; S02: Sampling the water outlet of the heater, the water inlet and the water outlet of the water-cooled wall simulation component through the sampling component, and detecting the conductivity of the three sampling points. If the conductivity does not meet the requirements, open the deoxygenated water tank to discharge sewage until the conductivity of the three sampling points meets the requirements; SO3: Turn on the dosing component, configure ammonia solution / ammonia + hydrazine solution in one of the dissolving boxes, adjust the pH value and hydrazine value in the system water sample until the pH value and hydrazine value of the three sampling points are qualified, and then stop dosing; S04: Turn on the cooler and the electric heater, start the heating mechanism of the water wall simulation component to heat the system water sample, configure an iron solution in one of the dissolving boxes, and turn on the dosing component to adjust the iron content in the system water sample. When the iron content indicators of the three sampling points are qualified, stop dosing; S05: When the iron content, pH value and hydrazine value in the water in the device are qualified, the test starts timing, and the oxygen content, iron content, pH / pH+hydrazine in the water sample are tested regularly. When the iron content and pH / pH+hydrazine are about to reach the lower limit of the control value, the iron content and pH / pH+hydrazine are adjusted to the control value range through the pressurizing component; when the test time is completed, the electric heater, water-cooled wall simulation component, and heat exchanger are turned off, and the water in the sampling component is discharged; S06: Cut the test tube sample on the water-cooled wall simulation assembly, detect the amount of scaling per unit area on the inner wall of the test tube sample, and calculate the scaling rate of the test tube sample under the test conditions, heat flux and water conditions in combination with the test time; by conducting orthogonal tests under different heat flux and water conditions, the scaling rate law of the heat exchange tube is obtained.

9. The method for using the boiler heat exchange tube scaling rate test device according to claim 8, characterized in that: The water operating conditions in step S06 include fully volatile reducing water conditions, fully volatile weakly oxidizing water conditions and oxidizing water conditions.

10. The method for using the boiler heat exchange tube scaling rate test device according to claim 9, characterized in that: When the working condition is full volatile reducing water, one of the solvent boxes is equipped with ammonia and hydrazine solution, and one of the solvent boxes is equipped with ferroferric oxide; When it is a fully volatile weakly oxidized water working condition, one of the dissolving tanks is equipped with ammonia solution, and one of the dissolving tanks is equipped with ferroferric oxide and ferric oxide solution; when the detected dissolved oxygen is greater than the set value, saturated steam is introduced into the deoxygenation water tank; When it is an oxidizing water condition, an ammonia solution is placed in one of the solvent boxes, and a ferric oxide solution is placed in another solvent box, and air is blown into the ferric oxide solution to make the dissolved oxygen concentration in the solution reach a saturated state; and saturated steam is introduced into the deoxygenation water tank; The saturation concentration of dissolved oxygen in water is: Among them, P is the measured atmospheric pressure; P0 is the standard atmospheric pressure; T is the water temperature; DO is the dissolved oxygen concentration; The actual value of dissolved oxygen in water detected by the sampling component is DO0, so the dosage of the dissolving box configured with ferric oxide solution is: Where DO is the dissolved oxygen concentration; DO0 is the actual value of dissolved oxygen; Q is the water flow rate in the test device; V 10 To control the dosage when the dissolved oxygen concentration in water is 10μg / L; V 50 To control the dosage when the dissolved oxygen concentration in water is 50μg / L; the dosage should be controlled at V 10 -V 50 between; In the fully volatile reducing water condition, the fully volatile weakly oxidizing water condition, and the oxidizing water condition, the heat flux calculation formula in step S06 is: Where, q is the heat flux; U is the voltage of the heating mechanism; I is the current of the heating mechanism; S 内 is the inner surface area of ​​the tested tube sample; The specific steps of step S06 are: after the test, cut the test tube sample, use 5% hydrochloric acid solution with corrosion inhibitor to clean the scaling product, and the scaling rate calculation formula is: Among them, m 前 is the mass of the test tube sample before cleaning, m 后 A is the quality of the test tube sample after cleaning, Fe is the scaling rate.

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