A waste incineration flue gas low-temperature corrosion test platform and working method

Abstract

The present application relates to waste incineration technical field, specifically to a kind of waste incineration flue gas low temperature corrosive test platform and working method.The platform includes the first pipeline connected with the flue gas outlet of bag filter and the second pipeline connected with the flue gas outlet of flue gas cooler, the outlet of the first pipeline and the outlet of the second pipeline are connected with first flue gas main pipe;The first flue gas main pipe is connected with multiple parallel heat exchange branch lines;Each heat exchange branch line is provided with heat exchanger, the heat exchange branch line is provided with flowmeter, flue gas volume regulating valve, temperature measuring point and induced draft fan;The outlet of the heat exchange branch line is connected with second flue gas main pipe, and the outlet of the second flue gas main pipe is connected with chimney and communicates;The cooling water outlet of all heat exchangers is connected with the first cooling water main pipe of cooling tower;The cooling water inlet of all heat exchangers is connected with the second cooling water main pipe of cooling tower.The test platform can be used for the corrosion resistance test and evaluation of various materials.

Description

Technical Field

[0001] This invention relates to the field of waste incineration technology, and in particular to a low-temperature corrosivity testing platform and working method for waste incineration flue gas. Background Technology

[0002] With the acceleration of urbanization, municipal solid waste treatment has become a crucial aspect of urban management. Waste incineration, as an efficient, volume-reducing, and harmless treatment method, is widely used. However, the flue gas produced during waste incineration has a complex composition, containing various harmful substances such as sulfur dioxide (SO2), hydrogen chloride (HCl), and heavy metals. These components exhibit strong corrosiveness under low-temperature conditions, posing a serious threat to the stable operation of incinerators and their supporting equipment.

[0003] Sulfur dioxide (SO2): Sulfur in waste produces sulfur dioxide during combustion, which is one of the main acidic gases. Under low-temperature conditions, some SO2 is further oxidized to SO3, which combines with water vapor to form sulfuric acid, causing the flue gas dew point temperature to rise and thus accelerating low-temperature corrosion.

[0004] Hydrogen chloride (HCl): Chlorine in waste will generate hydrogen chloride during the incineration process. HCl gas is not only harmful to human health and the environment, but it can also combine with moisture in flue gas to form an acidic environment, which will aggravate the corrosion of metal surfaces.

[0005] Heavy metals: Waste may contain heavy metals such as lead, mercury, and cadmium. These elements may exist in gaseous or solid form during incineration and are emitted through the flue gas system, causing corrosion to equipment and posing a risk of environmental pollution.

[0006] Low-temperature corrosion of flue gas refers to the phenomenon where acid vapors in the flue gas condense into acid liquid on the heated surface when the wall temperature of the heated surface is lower than the acid dew point in the flue gas, thereby causing severe corrosion to the metal of the heated surface.

[0007] Low-temperature corrosion is a particularly prominent problem during the operation of the tail-end heating surfaces of waste incinerators. Especially in the tail-end flue gas ducts, low-temperature economizers and flue gas condensers, the relatively low flue gas temperature and the presence of large amounts of acidic gases and moisture make them highly susceptible to acid dew point corrosion. Corrosion not only leads to rust on metal surfaces, shortening equipment lifespan, but can also cause ash blockage, further affecting the incinerator's operating efficiency and stability. The probability of low-temperature corrosion increases with the sulfur and chlorine content of the waste. Given the increasingly complex composition of waste, how to select suitable materials to effectively prevent low-temperature corrosion has become a pressing technical challenge for the waste incineration industry.

[0008] Currently, fluoroplastics have proven to be effective materials for heat exchangers that resist low-temperature corrosion at the tail end of waste incineration. However, they suffer from problems such as high price, weak pressure resistance, easy damage to heat exchange tubes, and low operating temperature. There is an urgent need to adopt suitable metal materials for application.

[0009] In the current field of waste incineration, although some research and countermeasures have been developed for high-temperature corrosion in flue gas, existing technologies still have significant shortcomings regarding low-temperature corrosion, particularly in evaluating the corrosiveness of waste incineration flue gas to various metal materials under low-temperature conditions. Specific shortcomings are as follows:

[0010] (1) Lack of comprehensive evaluation technology: Most existing experimental techniques and devices can only evaluate the corrosion resistance of a single metal material or a few specific materials. They cannot compare the corrosion resistance of multiple metal materials under the same flue gas conditions at the same time, resulting in one-sided evaluation results and difficulty in comprehensively guiding practical engineering applications.

[0011] (2) The experimental conditions are out of sync with the actual working conditions: The composition of flue gas from waste incineration is complex and varies greatly with factors such as the type of waste and the incineration process. Existing experimental devices often cannot accurately simulate the flue gas composition, temperature, humidity and other conditions in the actual incineration process, resulting in a large difference between the experimental results and the actual working conditions, and making it difficult to accurately reflect the corrosion of metal materials in actual use.

[0012] (3) Inconsistent evaluation methods and standards: Due to the lack of unified evaluation methods and standards, different research institutions or enterprises often use different experimental conditions, evaluation indicators and judgment standards when conducting low-temperature corrosion evaluation, resulting in a lack of comparability and repeatability between evaluation results, which is not conducive to the promotion and application of the technology. Summary of the Invention

[0013] To address the aforementioned problems, the present invention aims to provide a low-temperature corrosion testing platform and working method for waste incineration flue gas, used to test and evaluate the corrosion resistance of various materials, and thereby select metal materials resistant to low-temperature corrosion from waste incineration flue gas.

[0014] Specifically, this application provides the following technical solution:

[0015] A low-temperature corrosivity test platform for waste incineration flue gas includes a first pipeline connected to the flue gas outlet of a bag filter and a second pipeline connected to the flue gas outlet of a flue gas cooler. The outlets of the first pipeline and the second pipeline are both connected to a first flue gas header. The first flue gas header is connected to multiple parallel heat exchange branches.

[0016] Each heat exchange branch is equipped with a heat exchanger, a flow meter, a flue gas volume regulating valve, a temperature measuring point, and an induced draft fan; the outlet of each heat exchange branch is connected to the second flue gas header, and the outlet of the second flue gas header is connected to the chimney.

[0017] The cooling water outlets of all heat exchangers are connected to the first cooling water header of the cooling tower; the cooling water inlets of all heat exchangers are connected to the second cooling water header of the cooling tower.

[0018] Furthermore, a first regulating valve is provided on the first pipeline, a second regulating valve is provided on the second pipeline, and a flue gas main pipe temperature measuring point is provided on the first flue gas main pipe, the flue gas main pipe temperature measuring point being located in front of the inlet of the heat exchange branch.

[0019] Furthermore, the flow meter and flue gas volume regulating valve on the heat exchange branch are both located in front of the flue gas inlet of the heat exchanger.

[0020] Furthermore, the temperature measuring point and the induced draft fan on the heat exchange branch are located behind the flue gas outlet of the heat exchanger.

[0021] Furthermore, the cooling water outlet of the heat exchanger is connected to the first cooling water header via a pipe equipped with a temperature measuring point and a valve.

[0022] Furthermore, the second cooling water header is equipped with a cooling water header temperature measuring point and a third regulating valve.

[0023] Furthermore, the temperature measuring point of the cooling water header and the third regulating valve are located behind the outlet of the cooling tower.

[0024] Furthermore, all heat exchangers are made of different materials.

[0025] Furthermore, the flue gas outlet of the bag filter is connected to the inlet of the flue gas cooler; the flue gas outlet of the flue gas cooler is connected to the chimney.

[0026] The working method of the low-temperature corrosivity testing platform for waste incineration flue gas described in this invention includes the following steps:

[0027] ① Set the test flue gas temperature, and adjust the first regulating valve and the second regulating valve to minimize the difference between the flue gas header temperature measuring point and the set test flue gas temperature;

[0028] ②The test flue gas enters each heat exchanger for heat exchange after passing through the flue gas volume regulating valve of each heat exchange branch;

[0029] ③ Set the test flue gas volume, and adjust the flue gas volume regulating valve of each heat exchange branch to minimize the difference between the flue gas flow rate of each heat exchange branch and the set test flue gas volume;

[0030] ④ Cooling water is connected from the cooling tower to each heat exchanger through the second cooling water header, and after heat exchange, it returns to the cooling tower through the first cooling water header;

[0031] ⑤ Set the cooling water outlet temperature of the heat exchanger, and adjust the valves to minimize the difference between the cooling water outlet temperature of each heat exchange branch and the set cooling water outlet temperature of the heat exchanger.

[0032] ⑥ After heat exchange, the test flue gas enters the induced draft fan after passing through the temperature measuring point, and then is discharged to the chimney through the second flue gas header;

[0033] ⑦ Cut samples of the same shape and size from the base tubes of the heat exchanger used in the low-temperature flue gas environment of waste incineration at different times. Take a group of samples at each time and weigh them. Take at least 3 parallel samples in each group. Remove corrosion products according to the standard "Test Method for Corrosion Rate and Total Corrosion of Metals in Chemical Cleaning of Industrial Equipment" (GB / T 25147-2010) and then weigh them. Plot the corrosion kinetic curve (WS-T curve) based on the weight loss data, fit the curve to obtain a mathematical model, and then use it to predict the life of different materials and different parts.

[0034] Samples of the same shape and size were cut from the base tube of the heat exchanger after use at different times. A group of samples was taken at each time and weighed. At least three parallel samples were taken from each group for surface microscopic cross-section observation and measurement of corrosion product depth changes. A model of corrosion depth change over time (dt curve) was established, and a life prediction model for different materials was established to predict the material life.

[0035] ⑧Evaluate the corrosion resistance of different materials in each heat exchanger based on the predicted service life.

[0036] Compared with existing technologies, the low-temperature corrosivity testing platform and working method for waste incineration flue gas of the present invention have at least the following beneficial effects:

[0037] This invention draws a portion of the flue gas from the tail end of the bag filter in the waste incineration flue gas purification system and introduces it into this test platform. The flue gas then enters heat exchangers of different materials, which are cooled by cooling water. The heated cooling water is then cooled by a cooling tower, forming a continuously operating corrosion evaluation device.

[0038] This platform is a test platform and complete set of equipment that can simultaneously evaluate multiple metal materials, and can comprehensively and accurately assess the corrosion performance of waste incineration flue gas on multiple metal materials under low temperature conditions. (1) It realizes comprehensive evaluation of multiple materials: By designing an integrated test platform and complete set of equipment, it can simultaneously accommodate and test the corrosion resistance of multiple metal materials under the same flue gas conditions, providing a scientific basis for material selection, equipment design and anti-corrosion measures. (2) It accurately simulates actual working conditions: The test is conducted using actual waste incineration flue gas, ensuring that the test conditions are highly consistent with the actual incineration process, and improving the accuracy and practicality of the test results. (3) It unifies evaluation methods and standards: It formulates unified evaluation methods and standards to ensure that different research institutions or enterprises use the same test conditions, evaluation indicators and judgment standards when conducting low temperature corrosion evaluation, and improves the comparability and repeatability of evaluation results.

[0039] The low-temperature corrosion testing platform and working method for waste incineration flue gas of this invention effectively make up for the shortcomings of existing technologies in the low-temperature corrosion testing and evaluation of waste incineration flue gas. Through the implementation of this invention, the innovation and development of low-temperature corrosion evaluation technology for waste incineration flue gas can be promoted, providing strong support for the utilization of low-temperature waste heat in waste incineration technology, equipment anti-corrosion design and the research and development of anti-corrosion materials, and providing strong guarantee for the sustainable development of incineration technology and the continuous improvement of environmental protection requirements.

[0040] The following description, in conjunction with the accompanying drawings, further illustrates the low-temperature corrosivity testing platform and working method for waste incineration flue gas of the present invention. Attached Figure Description

[0041] The accompanying drawings in this application are intended to supplement the textual description in the specification with graphics, and to further explain the technical solution of this application. They do not constitute an undue limitation on this application.

[0042] Figure 1 This is a schematic diagram of the low-temperature corrosivity test platform for waste incineration flue gas of the present invention.

[0043] Among them, 1-bag filter; 2-flue gas cooler; 3-chimney; 4-cooling tower;

[0044] 11-First pipeline; 12-Second pipeline; 13-First flue gas header; 14-First cooling water header; 15-Second cooling water header; 16-Second flue gas header;

[0045] 101-First regulating valve; 102-Second regulating valve; 103-Temperature measuring point of flue gas main pipe; 104-Temperature measuring point of cooling water main pipe; 105-Third regulating valve;

[0046] 201 - First heat exchanger; 202 - Second heat exchanger; 203 - Third heat exchanger; 204 - Fourth heat exchanger; 205 - Fifth heat exchanger;

[0047] 301 - First flow meter; 302 - Second flow meter; 303 - Third flow meter; 304 - Fourth flow meter; 305 - Fifth flow meter;

[0048] 401 - First flue gas volume regulating valve; 402 - Second flue gas volume regulating valve; 403 - Third flue gas volume regulating valve; 404 - Fourth flue gas volume regulating valve; 405 - Fifth flue gas volume regulating valve;

[0049] 501 - First temperature measuring point; 502 - Second temperature measuring point; 503 - Third temperature measuring point; 504 - Fourth temperature measuring point; 505 - Fifth temperature measuring point;

[0050] 601 - First valve; 602 - Second valve; 603 - Third valve; 604 - Fourth valve; 605 - Fifth valve;

[0051] 701 - Sixth temperature measuring point; 702 - Seventh temperature measuring point; 703 - Eighth temperature measuring point; 704 - Ninth temperature measuring point; 705 - Tenth temperature measuring point;

[0052] 801 - First induced draft fan; 802 - Second induced draft fan; 803 - Third induced draft fan; 804 - Fourth induced draft fan; 805 - Fifth induced draft fan.

[0053] Figure 2 The corrosion kinetics curves for ND steel are shown.

[0054] Figure 3 The corrosion kinetics curves for 304 stainless steel are shown.

[0055] Figure 4 The corrosion kinetics curves for 316 stainless steel are shown.

[0056] Figure 5 The corrosion kinetics curves for 2205 stainless steel are shown.

[0057] Figure 6 The corrosion kinetics curves for 2507 stainless steel are shown.

[0058] Figure 7 The corrosion depth versus time curve for ND steel.

[0059] Figure 8 The corrosion depth versus time curve for 316 stainless steel.

[0060] Figure 9 The corrosion depth versus time curve for 2205 stainless steel.

[0061] Figure 10The corrosion depth versus time curve for 2507 stainless steel. Detailed Implementation

[0062] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0063] like Figure 1 As shown, a low-temperature corrosivity test platform for waste incineration flue gas includes a first pipe 11 connected to the flue gas outlet of a bag filter 1 and a second pipe 12 connected to the flue gas outlet of a flue gas cooler 2. The outlets of the first pipe 11 and the second pipe 12 are both connected to a first flue gas header 13. The first flue gas header 13 is connected to five parallel heat exchange branches. A first regulating valve 101 is provided on the first pipe 11, and a second regulating valve 102 is provided on the second pipe 12. A flue gas header temperature measuring point 103 is provided on the first flue gas header 13, and the flue gas header temperature measuring point 103 is located in front of the inlet of the heat exchange branches.

[0064] The five heat exchange branches are equipped with a first heat exchanger 201, a second heat exchanger 202, a third heat exchanger 203, a fourth heat exchanger 204, and a fifth heat exchanger 205, respectively. The cooling water outlets of all heat exchangers are connected to the first cooling water header 14 of the cooling tower 4; the cooling water inlets of all heat exchangers are connected to the second cooling water header 15 of the cooling tower 4.

[0065] The cooling water outlet of the first heat exchanger 201 is connected to the first cooling water header 14 via a pipe equipped with a first temperature measuring point 501 and a first valve 601. The cooling water outlet of the second heat exchanger 202 is connected to the first cooling water header 14 via a pipe equipped with a second temperature measuring point 502 and a second valve 602. The cooling water outlet of the third heat exchanger 203 is connected to the first cooling water header 14 via a pipe equipped with a third temperature measuring point 503 and a third valve 603. The cooling water outlet of the fourth heat exchanger 204 is connected to the first cooling water header 14 via a pipe equipped with a fourth temperature measuring point 504 and a fourth valve 604. The cooling water outlet of the fifth heat exchanger 205 is connected to the first cooling water header 14 via a pipe equipped with a fifth temperature measuring point 505 and a fifth valve 605.

[0066] The second cooling water header 15 is equipped with a cooling water header temperature measuring point 104 and a third regulating valve 105. The cooling water header temperature measuring point 104 and the third regulating valve 105 are located behind the outlet of the cooling tower 4.

[0067] The cooling water exiting cooling tower 4 passes through the second cooling water header 15 and then branches into five heat exchangers via five separate pipes to cool the flue gas. After passing through the heat exchangers, the water temperature rises, and the water then flows back into the cooling tower through the first cooling water header 14 for further cooling. Each of the five heat exchangers has a temperature measuring point on its outlet pipe to measure the water temperature, and five valves to regulate the cooling water flow. The second cooling water header 15 has a cooling water header temperature measuring point 104 to measure the cooling tower outlet water temperature, and a third regulating valve 105 to regulate the cooling water flow rate at the cooling tower outlet.

[0068] The first heat exchange branch is equipped with a first flow meter 301, a first flue gas flow regulating valve 401, a sixth temperature measuring point 701, and a first induced draft fan 801. The second heat exchange branch is equipped with a second flow meter 302, a second flue gas flow regulating valve 402, a seventh temperature measuring point 702, and a second induced draft fan 802. The third heat exchange branch is equipped with a third flow meter 303, a third flue gas flow regulating valve 403, an eighth temperature measuring point 703, and a third induced draft fan 803. The fourth heat exchange branch is equipped with a fourth flow meter 304, a fourth flue gas flow regulating valve 404, a ninth temperature measuring point 704, and a fourth induced draft fan 804. The fifth heat exchange branch is equipped with a fifth flow meter 305, a fifth flue gas flow regulating valve 405, a tenth temperature measuring point 705, and a fifth induced draft fan 805. All flow meters and flue gas flow regulating valves on all heat exchange branches are located upstream of the flue gas inlet of the heat exchanger. All temperature measuring points and induced draft fans on the heat exchange branches are located behind the flue gas outlet of the heat exchanger.

[0069] The flue gas outlet of the bag filter 1 is connected to the inlet of the flue gas cooler 2; the flue gas outlet of the flue gas cooler 2 is connected to the chimney 3. The flue gas from the bag filter 1 passes through the flue gas cooler 2 and then enters the chimney 3 for discharge. A first pipe 11 and a second pipe 12 are respectively used to draw out the flue gas before and after the flue gas cooler. The flue gas temperatures drawn out through the first pipe 11 and the second pipe 12 are different, with the flue gas temperature in the first pipe 11 being higher and the flue gas temperature in the second pipe 12 being lower. The first pipe 11 and the second pipe 12 are respectively equipped with a first regulating valve 101 and a second regulating valve 102, which can be used to regulate the temperature of the flue gas entering the test platform from the flue gas cooler.

[0070] The flue gas from the first pipeline 11 and the second pipeline 12 merges and enters the first flue gas header 13. The flue gas from the first flue gas header 13 then passes through five branch pipelines into five heat exchangers. After passing through the heat exchangers, the flue gas passes through five induced draft fans and converges into the second flue gas header 16, from which it is discharged into the chimney 3. Temperature measuring points are installed on the pipelines between the heat exchangers and the induced draft fans to measure the temperature of the flue gas from each branch after passing through the heat exchangers.

[0071] All heat exchangers are made of different materials, so multiple materials were tested simultaneously.

[0072] The working method and specific steps of this low-temperature corrosivity testing platform for waste incineration flue gas are as follows:

[0073] (1) Set the test flue gas temperature, and adjust the first regulating valve 101 and the second regulating valve 102 to minimize the difference between the flue gas header temperature measuring point 103 and the set test flue gas temperature;

[0074] (2) After passing through the flue gas flow regulating valve of each heat exchange branch, the test flue gas enters the first heat exchanger 201 to the fifth heat exchanger 205 for heat exchange.

[0075] (3) Set the test flue gas volume and adjust the flue gas volume regulating valves (first flue gas volume regulating valve 401 to fifth flue gas volume regulating valve 405) of each heat exchange branch to minimize the difference between the flue gas flow rate (measured by the first flow meter 301 to the fifth flow meter 305) of each heat exchange branch and the set test flue gas volume.

[0076] (4) Cooling water is connected from the cooling tower 4 to each heat exchanger through the second cooling water header 15, and after heat exchange, it returns to the cooling tower 4 through the first cooling water header 14.

[0077] (5) Set the cooling water outlet temperature of the heat exchanger. By adjusting the first valve 601 to the fifth valve 605, the difference between the cooling water outlet temperature of each heat exchange branch (measured by the first temperature measuring point 501 to the fifth temperature measuring point 505) and the set cooling water outlet temperature of the heat exchanger is minimized.

[0078] (6) After heat exchange, the test flue gas passes through 5 temperature measuring points (sixth temperature measuring point 701 to tenth temperature measuring point 705) and then enters 5 induced draft fans (first induced draft fan 801 to fifth induced draft fan 805), and is then discharged to the chimney 3 through the second flue gas header 16.

[0079] (7) Cut off samples of the same shape and size from the base tubes of the five heat exchangers 201-205 after use in the low-temperature flue gas environment of waste incineration at different times. Take a group of samples at each time and weigh them. Take at least three parallel samples from each group. Remove corrosion products according to the standard "Test Method for Corrosion Rate and Total Corrosion of Metals in Chemical Cleaning of Industrial Equipment" (GB / T 25147-2010) and then weigh them. Plot the corrosion kinetic curve (ws-t curve) based on the weight loss data, fit the curve to obtain a mathematical model, and then use it to predict the life of five different materials at different parts.

[0080] Samples of the same shape and size were cut from the base tubes of five heat exchangers 201-205 after use at different times. A group of samples was taken from each time period and weighed. At least three parallel samples were taken from each group for surface microscopic cross-section observation and measurement of corrosion product depth changes. A model of corrosion depth change over time (dt curve) was established, and five different material life prediction models were established to predict the material service life.

[0081] (8) Based on the predicted service life, the corrosion resistance of different materials in the five heat exchangers can be evaluated.

[0082] Application Examples

[0083] The experimental platform of this invention was used to conduct a low-temperature corrosion test on the tail flue gas of the flue gas purification system of a waste incineration power plant in Shanxi Province. Suitable metal heat exchange materials were selected from the test results for low-temperature waste heat utilization in waste incineration power plants, which can improve power generation efficiency, reduce carbon emissions, and has good economic, environmental and carbon emission reduction benefits.

[0084] The experiment selected heat exchangers with five different base tube materials: 09CrCuSb (hereinafter referred to as ND steel), 304 stainless steel, 316L stainless steel, 2205 stainless steel and 2507 stainless steel.

[0085] The test flue gas temperature was set at 140℃, and the test flue gas volume was set at 1000 m³ / h. 3 / h, set the cooling water outlet temperature of the heat exchanger to 48℃.

[0086] After 10, 30, and 60 days of service in the low-temperature flue gas environment of waste incineration, the heat exchange tubes were removed. Corrosion weight loss samples and maximum corrosion depth samples were processed for five different materials in each cycle. Corrosion weight loss and maximum pitting depth were measured for the samples in accordance with GB / T 25147-2010 Test method for corrosion rate and total corrosion of metals in chemical cleaning of industrial equipment and ISO 4969-1980 Macroscopic inspection of steel under strong mineral acid corrosion. Corrosion kinetic curves and corrosion depth change curves over time were established.

[0087] 1. Corrosion weight loss detection

[0088] After macroscopic analysis of the surfaces of five samples from different periods, samples were taken from severely corroded areas to ensure that the effective test area of ​​the samples was 100mm × 20mm. Three parallel samples were taken from each sample for pickling and rust removal. After the samples were placed in a desiccator for 24 hours, they were weighed and the average corrosion weight loss was recorded. The test results are shown in the table below.

[0089] Table 1. Corrosion weight loss data of five samples after 10, 30, and 60 days of corrosion.

[0090]

[0091] The average corrosion weight loss of five different tests over three cycles (test durations of 10 days, 30 days, and 60 days) was fitted, as follows: Figure 2-6 As shown.

[0092] 2. Maximum corrosion depth detection

[0093] Macroscopic testing was conducted on five types of samples. For ND steel, samples were taken from the average corrosion sites and prepared for metallographic analysis perpendicular to the pipe diameter. For 304, 316, 2205, and 2507 stainless steel, which exhibited severe pitting corrosion, samples were prepared perpendicular to the pipe diameter at the locations of the largest pits. The maximum pitting depths for different test cycles are shown in Table 2.

[0094] Table 2 Corrosion depth data of five samples after 10, 30, and 60 days of corrosion.

[0095]

[0096] Curves were established for the average corrosion depth of ND steel and the maximum pitting depth of 316 stainless steel, 2205 stainless steel and 2507 stainless steel, respectively. Figure 7-10 As shown, a through-matrix crack was detected in 304 stainless steel during the third cycle, making it impossible to establish a corrosion depth versus time curve.

[0097] It can be seen that the low-temperature corrosion test platform for waste incineration flue gas can provide flue gas corrosion tests under actual working conditions, providing an important basis for the material selection and optimization design of related equipment. (1) By adjusting the flue gas volume before and after the flue gas cooler, the temperature of the flue gas entering the test platform can be effectively controlled, thereby realizing the corrosion resistance test of heat exchanger materials under various flue gas temperatures. (2) By adjusting the flue gas volume and cooling water flow rate of the branch pipeline, corrosion resistance tests can be realized under various flue gas temperature and cooling water temperature conditions. (3) Flue gas extraction and temperature control system: By extracting part of the flue gas from the tail of the bag filter and setting two pipelines with different temperatures and corresponding regulating valves, the temperature of the flue gas entering the test platform can be accurately controlled, thereby enabling the study of flue gas corrosivity at different temperatures. (4) Multi-channel heat exchangers and flue gas flow regulation: The main pipe merges the flue gas from the two pipelines and then enters the five heat exchangers through five branch pipes. Each branch pipe is equipped with a flow meter and a flue gas flow regulating valve. This allows the test to simultaneously test the corrosivity of multiple materials under different flue gas conditions, improving the efficiency and accuracy of the test. (5) Cooling water circulation and temperature monitoring: The cooling water from the cooling tower enters the five heat exchangers through the main pipe and five branch pipes to cool the flue gas. At the same time, temperature measuring points and valves are installed on the outlet pipe of each heat exchanger to measure the water temperature and regulate the flow of cooling water. This design ensures the effective use and precise control of cooling water, thereby ensuring the accuracy of the test results. (6) Comprehensive temperature and flow monitoring: Multiple temperature measuring points and flow meters are set up throughout the test platform, including temperature measuring points on the main pipe, temperature measuring points after the heat exchangers, and flow meters and regulating valves on each branch pipe. These monitoring points can provide real-time feedback on temperature and flow information during the test, providing comprehensive data support for the test personnel and helping to study the low-temperature corrosivity of flue gas in greater depth.

[0098] In summary, the low-temperature corrosivity testing platform for waste incineration flue gas of the present invention has the following advantages:

[0099] 1. Simultaneous evaluation of multiple materials: The test platform of this invention can simultaneously test the corrosion resistance of multiple metal materials under the same flue gas conditions, realizing the comprehensive evaluation of multiple materials and significantly improving the scientificity and accuracy of material selection and equipment design.

[0100] 2. Accurate simulation of operating conditions: The test uses actual waste incineration flue gas to ensure that the experimental conditions are highly consistent with the actual incineration process, thereby improving the accuracy and practicality of the experimental results and making the evaluation results more practically instructive.

[0101] 3. Unified evaluation standards: This ensures that the same experimental conditions, evaluation indicators, and judgment criteria are used when evaluating low-temperature corrosion, thus enhancing the comparability and repeatability of the evaluation results.

[0102] 4. Continuous long-term testing: The test platform of this invention is a continuously operating corrosion evaluation device that can continuously conduct tests, significantly improving test efficiency and reducing the cost of a single test, which is conducive to long-term and stable corrosion research.

[0103] 5. Comprehensive monitoring and adjustment: The test platform is equipped with multiple temperature measuring points, flow meters, and regulating valves, enabling comprehensive monitoring and precise adjustment of flue gas temperature, flow rate, and cooling water temperature. This ensures the stability and accuracy of the test process and provides abundant data support.

[0104] 6. Flexibility and scalability: The heat exchangers can be made of different materials, and multiple materials can be tested simultaneously, giving the invention high flexibility and scalability. More heat exchangers can be added or test conditions adjusted as needed to meet the corrosion evaluation requirements of different materials and operating conditions.

[0105] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A working method for a low-temperature corrosivity testing platform for waste incineration flue gas, characterized in that: The waste incineration flue gas low-temperature corrosivity test platform includes a first pipeline (11) connected to the flue gas outlet of the bag filter (1) and a second pipeline (12) connected to the flue gas outlet of the flue gas cooler (2). The outlets of the first pipeline (11) and the second pipeline (12) are both connected to the first flue gas main pipe (13), which is connected to multiple parallel heat exchange branches. Each heat exchange branch is equipped with a heat exchanger, a flow meter, a flue gas volume regulating valve, a temperature measuring point and an induced draft fan. The outlet of each heat exchange branch is connected to the second flue gas main pipe (16), and the outlet of the second flue gas main pipe (16) is connected to the chimney (3). The cooling water outlets of all heat exchangers are connected to the first cooling water header (14) of the cooling tower (4), and the cooling water inlets of all heat exchangers are connected to the second cooling water header (15) of the cooling tower (4). The first pipeline (11) is provided with a first regulating valve (101), the second pipeline (12) is provided with a second regulating valve (102), and the first flue gas header (13) is provided with a flue gas header temperature measuring point (103), which is located in front of the inlet of the heat exchange branch. The flow meter and flue gas volume regulating valve on the heat exchange branch are both located in front of the flue gas inlet of the heat exchanger. The temperature measuring points and induced draft fans on the heat exchange branches are all located behind the flue gas outlet of the heat exchanger; all heat exchangers are made of different materials. Specifically, the following steps are included: ① Set the test flue gas temperature, and by adjusting the first regulating valve (101) and the second regulating valve (102), minimize the difference between the flue gas header temperature measuring point (103) and the set test flue gas temperature; ②The test flue gas enters each heat exchanger for heat exchange after passing through the flue gas volume regulating valve of each heat exchange branch; ③ Set the test flue gas volume, and adjust the flue gas volume regulating valve of each heat exchange branch to minimize the difference between the flue gas flow rate of each heat exchange branch and the set test flue gas volume; ④ Cooling water is connected from the cooling tower (4) to each heat exchanger through the second cooling water header (15), and after heat exchange, it returns to the cooling tower (4) through the first cooling water header (14). ⑤ Set the cooling water outlet temperature of the heat exchanger, and adjust the valves to minimize the difference between the cooling water outlet temperature of each heat exchange branch and the set cooling water outlet temperature of the heat exchanger. ⑥ The test flue gas after heat exchange enters the induced draft fan after passing through the temperature measuring point, and is then discharged to the chimney (3) through the second flue gas header (16). ⑦ Cut samples of the same shape and size from the base tubes of the heat exchanger used in the low-temperature flue gas environment of waste incineration at different times. Take a group of samples at each time and weigh them. Take at least 3 parallel samples from each group. Remove corrosion products according to the standard "Test Method for Corrosion Rate and Total Corrosion of Metals in Chemical Cleaning of Industrial Equipment" (GB / T 25147-2010), and then weigh them. Plot the corrosion kinetic curve based on the weight loss data, fit the curve to obtain a mathematical model, and then use it to predict the life of different materials and different parts. Samples of the same shape and size were cut from the base tube of the heat exchanger after use at different times. A group of samples was taken at each time and weighed. At least three parallel samples were taken from each group. The surface micro-section was observed and the change in corrosion product depth was measured. A model of corrosion depth change over time was established, and a life prediction model for different materials was established to predict the life of the materials. ⑧Evaluate the corrosion resistance of different materials in each heat exchanger based on the predicted service life.

2. The working method of the low-temperature corrosivity test platform for waste incineration flue gas according to claim 1, characterized in that: Temperature measuring points and valves are provided on the pipeline connecting the cooling water outlet of the heat exchanger to the first cooling water header (14).

3. The working method of the low-temperature corrosivity test platform for waste incineration flue gas according to claim 1, characterized in that: The second cooling water header (15) is equipped with a cooling water header temperature measuring point (104) and a third regulating valve (105).

4. The working method of the low-temperature corrosivity test platform for waste incineration flue gas according to claim 3, characterized in that: The cooling water header temperature measuring point (104) and the third regulating valve (105) are located behind the outlet of the cooling tower (4).

5. The working method of the low-temperature corrosivity test platform for waste incineration flue gas according to claim 1, characterized in that: The flue gas outlet of the bag filter (1) is connected to the inlet of the flue gas cooler (2), and the flue gas outlet of the flue gas cooler (2) is connected to the chimney (3).

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