Smoke acquisition system and method for smoke exhaust simulation test of ship power device

Abstract

The invention discloses a smoke acquisition system for a smoke exhaust simulation test of a ship power device. The smoke acquisition system comprises a combustion chamber, a smoke exhaust pipe, a chimney and at least one temperature reduction piece, a combustor is arranged in the combustion chamber and communicated with a fuel oil supply pipeline and an air supply pipeline. A top outlet of the combustor is communicated with the lower end of the smoke exhaust pipe above; the upper end of the smoke exhaust pipe is connected with a chimney; the temperature reduction piece is arranged in the combustor or the smoke exhaust pipe, and an inlet of the temperature reduction piece is communicated with the water supply pipeline; a smoke temperature sensor is arranged at an outlet of the chimney. The invention further discloses a smoke obtaining method for the smoke exhaust simulation test of the ship power device. The method has the beneficial effects that the target flue gas with the corresponding flow and temperature is obtained according to the flue gas discharge characteristics of different ship power devices, and the flue gas simulation test of flue gas discharge control of different ship power devices can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of power system test verification, and in particular to a smoke acquisition system and method for a smoke exhaust simulation test of a ship power unit. Background Art

[0002] The flue gas temperature of ship power plants such as gas turbines, main boilers, and diesel engines is generally between 300℃ and 500℃. The infrared radiation generated by them seriously affects the infrared stealth of ships, and pollutants such as soot particles in the flue gas are prone to cause environmental pollution. Therefore, the flue gas needs to be cooled. In recent years, the treatment technology for power plant exhaust has been continuously developed, and the verification of flue gas treatment technology is the most reliable means to evaluate the treatment effect.

[0003] To conduct flue gas tests, it is first necessary to simulate and generate flue gas with a certain flow rate and temperature similar to the actual power unit. Generating hot flue gas through combustion is a more effective technical approach. Considering the feasibility of the technology and the controllable risks, the existing technology uses the method of generating simulated hot flue gas based on the transformation of mature power units such as boilers as a more feasible technical solution. However, traditional power units such as boilers adjust and control the exhaust parameters with the goal of obtaining efficient heat exchange. The flue gas temperature and flow rate are related to the required energy and are fixed, and generally the exhaust temperature is reduced as much as possible (about 150℃~200℃) to improve thermal efficiency. To conduct hot flue gas tests, it is necessary to adjust and set the flow rate and temperature of the hot flue gas according to the test object, and in order to simulate the exhaust of ship engines, the initial temperature of the simulated flue gas is required to be between 390~550℃. Therefore, its control method is quite different from the traditional boiler exhaust control method used in existing flue gas tests. In addition, since the flue gas and flow rate required to simulate different power units may be different, and the flue gas temperature has a greater impact on the infrared characteristics, the control accuracy requirements are also different. The existing hot flue gas tests using traditional boilers and other power units cannot simulate the exhaust of different ship power units. Summary of the invention

[0004] The purpose of the present invention is to provide a smoke acquisition system and method for ship power plant exhaust simulation test to address the deficiencies of the prior art, aiming to provide smoke of different temperatures for different ship power plant exhaust simulation tests.

[0005] The technical solution adopted by the present invention is: a smoke acquisition system for a smoke exhaust simulation test of a ship power plant, comprising a combustion chamber, a smoke exhaust pipe, a chimney, and at least one temperature reducing component; A burner is arranged in the combustion chamber, and the burner is connected with a fuel supply pipeline and an air supply pipeline; The top outlet of the burner is connected to the lower end of the smoke exhaust pipe above; The upper end of the smoke exhaust pipe is connected to the chimney; The temperature reducing element is arranged inside the burner or the smoke exhaust pipe, and the inlet of the temperature reducing element is connected with the water supply pipeline; A smoke temperature sensor is arranged at the outlet of the chimney.

[0006] According to the above scheme, the flue gas acquisition system includes a primary cooling element and a secondary cooling element; the primary cooling element and the secondary cooling element are respectively arranged inside the combustion chamber from bottom to top, and the inlets of the primary cooling element and the secondary cooling element are respectively connected to the water supply pipeline; The outlet of the first-stage cooling element is communicated with the inlet end of the second-stage cooling element through a pipeline.

[0007] According to the above scheme, the flue gas acquisition system also includes a three-stage cooling element, the outlet end of which is connected to the inside of the exhaust pipe; smoke temperature sensors are respectively arranged in the exhaust pipe upstream and downstream of the outlet end of the three-stage cooling element.

[0008] According to the above scheme, a fuel regulating valve is arranged on the fuel supply pipeline, and an air regulating valve and a blower are arranged on the air supply pipeline.

[0009] According to the above solution, the primary cooling element is a primary cooling coil, and the secondary cooling element is a secondary cooling coil.

[0010] According to the above scheme, the inlet ends of the first-stage cooling coil and the second-stage cooling coil are respectively connected to the water supply pipeline; the outlet of the first-stage cooling coil is connected to the outlet pipeline, and a steam-water separator is arranged on the outlet pipeline. The steam outlet of the steam-water separator is connected to the inlet of the second-stage cooling coil through the steam pipeline, and the outlet of the second-stage cooling coil is connected to the steam exhaust pipeline.

[0011] According to the above scheme, a water pump and a water valve are arranged on the water supply pipeline, and a buffer ball is arranged on the downstream pipeline of the water pump.

[0012] According to the above scheme, the three-stage cooling component is a cold air pipeline, the outlet of the cold air pipeline is connected to the inside of the smoke exhaust pipe, and a cold air valve is arranged on the cold air pipeline; the inlet of the cold air pipeline is connected to the air supply pipeline.

[0013] The present invention also discloses a smoke acquisition method for a smoke exhaust verification test of a ship power plant, the method comprising: Providing a smoke acquisition system as described above, and determining the flow rate and temperature of the target smoke; According to the target flue gas flow rate, calculate the fuel quantity of the burner, and then determine the fuel pressure and the opening of the fuel regulating valve; Distribute air according to the amount of fuel in the burner, obtain the air volume under the target flue gas flow rate, and determine the opening of the air regulating valve on the air supply pipeline; The burner ignites and burns to generate smoke. At the same time, the water valve on the water supply pipeline opens to supply cooling water to the primary and secondary cooling components respectively; the cold air pipeline supplies cold air to the exhaust pipe; The cooling water in the primary cooling element exchanges heat with the flue gas in the combustion chamber through radiation convection and radiation heat exchange. The cooling water in the primary cooling element absorbs heat and turns into steam. After passing through the steam-water separator, saturated steam is generated. The saturated steam is then sent to the secondary cooling element at the top of the combustion chamber to absorb heat. At the same time, feed water is added to further reduce the exhaust gas temperature after heat exchange with the flue gas. The first smoke temperature sensor in the smoke exhaust pipe detects the smoke temperature at the entrance of the smoke exhaust pipe. When the difference between the smoke temperature and the target temperature is detected to be less than 5°C, the air valve in the cold air duct is closed. When the smoke temperature is detected to be higher than the target temperature by more than 5°C, the amount of cold air required to reduce the smoke to the target temperature is calculated and the opening of the air valve is adjusted to perform three-level cooling on the smoke in the smoke exhaust pipe until the third smoke temperature sensor at the chimney outlet detects that the temperature of the smoke is reduced to the target temperature.

[0014] According to the above scheme, the specific method of air distribution according to the fuel amount of the burner is: determine the fuel amount under the maximum flow condition and the minimum flow condition according to the flue gas flow range of the ship power unit, determine the fuel pressure and the opening of the fuel regulating valve, and then determine the damper opening of each set point according to the flue gas oxygen content detected by the flue gas analyzer in the hot state, so as to determine the combustion air distribution under different fuel amounts, that is, determine the excess air coefficient, and then draw the air-oil configuration curve according to the obtained fuel amount and air volume data, that is, adjust a flue gas flow that changes linearly with the combustion rate; finally, the corresponding fuel air distribution can be obtained from the curve according to the target flue gas flow.

[0015] The beneficial effects of the present invention are: 1. The present invention can adjust the air-oil ratio by adjusting the flow rates of the fuel supply pipeline and the air supply pipeline according to the exhaust characteristics of different ship power plants, obtain the target flue gas of the corresponding flow rate, and adjust the temperature of the flue gas through the cooling element to obtain the target flue gas of the corresponding temperature. Compared with the prior art, the present invention can meet the flue gas simulation test of exhaust control of different ship power plants. The obtained flue gas can realize the precise control of the flue gas flow rate and temperature in the simulation test, and provide a reference for the exhaust control of actual ship power plants.

[0016] 2. The present invention uses cooling coils as primary and secondary cooling components to cool the flue gas. This cooling method does not change the composition of the flue gas, thus reducing test errors.

[0017] 3. In the present invention, the first-stage cooling element is used to roughly adjust the flue gas so that the difference between the flue gas temperature and the target temperature is within 15°C; the second-stage cooling element and the third-stage cooling element are used to finely adjust the flue gas temperature so that the difference between the flue gas temperature and the target temperature is within 5°C, and feedback adjustment is performed. This graded temperature control method is safe and reliable, highly flexible, and can obtain flue gas with different target temperatures. The entire system and method are highly versatile.

[0018] 4. The system and method of the present invention can be used to obtain experimental flue gas, and can also be used for cooling and discharging flue gas in actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Among them: 1-combustion chamber; 2-first-stage cooling component; 3-second-stage cooling component; 4-water supply pump; 5-steam-water separator; 6-smoke exhaust pipe; 7-chimney; 8-smoke temperature sensor; 9-buffer ball; 10-cold air pipeline; 11-export pipeline; 12-steam pipeline; 13-water supply pipeline; 14-steam exhaust pipeline; 15-safety discharge pipeline; 16-soot blowing pipeline; 17, muffler. DETAILED DESCRIPTION

[0021] In order to better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0022] like Figure 1 The figure shows a flue gas acquisition system, specifically a flue gas acquisition system for a ship power plant exhaust simulation test, comprising a combustion chamber 1, a smoke exhaust pipe 6, a chimney 7 and at least one temperature reducing component; The combustion chamber 1 is provided with a burner, and the burner is connected with a fuel supply pipeline and an air supply pipeline; The top outlet of the burner is connected to the lower end of the smoke exhaust pipe 6 above; The upper end of the smoke exhaust pipe 6 is connected to the chimney 7; The temperature reducing component is arranged in the combustion chamber 1, and the inlet of the temperature reducing component is connected with the water supply pipeline; A smoke temperature sensor 8 is provided at the outlet of the chimney 7 .

[0023] In the present invention, the flue gas acquisition system includes a primary cooling element 2 and a secondary cooling element 3; The primary cooling element 2 and the secondary cooling element 3 are respectively arranged inside the combustion chamber 1 from bottom to top, and the inlets of the primary cooling element 2 and the secondary cooling element 3 are respectively connected to the water supply pipeline; The outlet of the primary cooling element 2 is connected to the inlet of the secondary cooling element 3 through a pipeline.

[0024] Preferably, the flue gas acquisition system further comprises a three-stage cooling element, the outlet end of which is connected to the inside of the smoke exhaust pipe 6; smoke temperature sensors 8 are respectively arranged in the smoke exhaust pipe 6 upstream and downstream of the outlet end of the three-stage cooling element.

[0025] In the present invention, a fuel regulating valve is arranged on the fuel supply pipeline, and an air regulating valve and a blower are arranged on the air supply pipeline.

[0026] In the present invention, a first smoke temperature sensor and a second smoke temperature sensor are respectively arranged in the smoke exhaust pipe 6 upstream and downstream of the outlet end of the third-stage cooling element; and a third smoke temperature sensor is arranged at the outlet of the chimney 7 .

[0027] Preferably, the first-level cooling component 2 is a first-level cooling coil, and the second-level cooling component 3 is a second-level cooling coil; the inlet ends of the first-level cooling coil and the second-level cooling coil are respectively connected to the water supply pipeline; a water pump and a water valve are provided on the water supply pipeline, and a buffer ball 9 is arranged on the downstream pipeline of the water pump; the outlet of the first-level cooling coil is connected to the outlet pipeline 11, and a steam-water separator 5 is arranged on the outlet pipeline 11, and the steam outlet of the steam-water separator 5 is connected to the inlet of the second-level cooling coil through the steam pipeline 12, and the outlet of the second-level cooling coil is connected to the steam exhaust pipeline 14.

[0028] In the present invention, the flue gas generated in the combustion chamber 1 is subjected to primary and secondary cooling by the primary cooling element 2 and the secondary cooling element 3. The steam generated in the primary cooling coil enters the secondary cooling coil through the steam pipeline and mixes with the cooling water in the secondary cooling coil.

[0029] Preferably, the three-stage cooling component is a cold air duct 10, the outlet of the cold air duct 10 is connected to the inside of the smoke exhaust pipe 6, and a cold air valve is arranged on the cold air duct 10; the inlet of the cold air duct 10 is connected to the air supply pipeline, specifically, connected to the blower on the air supply pipeline.

[0030] In the present invention, a three-stage cooling element is used to further cool the smoke in the smoke exhaust pipe 6 .

[0031] In the present invention, three smoke temperature sensors detect the smoke temperature respectively.

[0032] In the present invention, a flow rate detection sensor for detecting the flue gas flow rate and a flue gas analyzer for detecting the flue gas components are arranged in the smoke exhaust pipe 6 .

[0033] In the present invention, a silencer 17 and a steam emptying device are sequentially arranged at the end of the steam exhaust pipeline 14 along the steam flow direction; the upper part of the steam-water separator 5 is also connected to a safety exhaust pipeline 15, and a safety valve is arranged on the safety exhaust pipeline 15; the steam pipeline 12 at the outlet of the steam-water separator 5 is also connected to a soot blowing pipeline 16, and the soot blowing pipeline 16 is connected to the inner bottom of the exhaust pipe 6 for regular soot blowing maintenance of the heat exchanger.

[0034] A flue gas acquisition method, specifically a flue gas acquisition method for a ship power plant exhaust verification test, the method comprising: Providing a smoke acquisition system as described above, and determining the flow rate and temperature of the target smoke; According to the target flue gas flow rate, calculate the fuel quantity of the burner, and then determine the fuel pressure and the opening of the fuel regulating valve; Distribute air according to the amount of fuel in the burner, obtain the air volume under the target flue gas flow rate, and determine the opening of the air regulating valve on the air supply pipeline; The burner ignites and burns to generate smoke, and at the same time, the water valve on the water supply pipeline opens to supply cooling water to the primary cooling element 2 and the secondary cooling element 3 respectively; the cold air pipeline 10 opens to supply cold air to the exhaust pipe 6; The cooling water in the primary cooling element 2 exchanges heat with the flue gas in the combustion chamber 1 through radiation convection and radiation heat exchange, so that the difference between the flue gas temperature passing through the primary cooling element and the target temperature is less than 15°C, and the flue gas temperature is roughly adjusted (primary cooling adjustment); the cooling water in the primary cooling element 2 absorbs heat and turns into steam, and generates saturated steam after passing through the steam-water separator 5, and then the saturated steam is sent to the secondary cooling element 3 at the top of the combustion chamber 1 to absorb heat, and at the same time, feed water is added, and the exhaust gas temperature is further reduced after heat exchange with the flue gas (secondary cooling adjustment). At this time, the temperature of the superheated steam is about 200°C, which is close to the target flue gas temperature; the control is relatively easy; after two-stage cooling, the flue gas temperature can be adjusted to a difference of about 10°C from the target flue gas temperature; The first smoke temperature sensor in the smoke exhaust pipe 6 detects the smoke temperature at the entrance of the smoke exhaust pipe 6. When the difference between the smoke temperature and the target temperature is detected to be less than 5°C, the air valve in the cold air duct 10 is closed; when the smoke temperature is detected to be higher than the target temperature by more than 5°C, the amount of cold air required to reduce the smoke to the target temperature is calculated and the opening of the air valve is adjusted to perform three-stage cooling of the smoke in the smoke exhaust pipe 6 until the third smoke temperature sensor at the outlet of the chimney 7 detects that the temperature of the smoke is reduced to the target temperature.

[0035] Since the flue gas flow rate range of the ship's power unit is 2kg / s ~ 10kg / s, and the temperature range is 290℃ ~ 550℃, appropriate components such as valves, fans, water pumps, etc. can be selected according to the maximum flow condition, minimum flow condition, and maximum temperature condition respectively.

[0036] In the present invention, the flue gas temperature is first roughly adjusted by the primary cooling element 2 so that the difference between the flue gas temperature and the target temperature is within 15°C; then, the secondary cooling element 3 and the tertiary cooling element are finely adjusted, so that the flue gas temperature can be theoretically consistent with the target temperature, and in practice, the difference between the flue gas temperature and the target temperature can be controlled within 5°C.

[0037] In the present invention, the specific method for air distribution according to the fuel amount of the burner is: determine the fuel amount under the maximum flow condition and the minimum flow condition according to the flue gas flow range of the ship power unit (that is, determine the fuel pressure and the opening of the fuel regulating valve), and then, in the furnace ignition state, determine the damper opening of each set point according to the flue gas oxygen content detected by the flue gas analyzer (specifically, the flue gas oxygen content can calculate the amount of air in the flue gas that does not participate in combustion, and judge whether it is completely burned and whether it is within a reasonable excess air coefficient range; the damper opening can be understood as the valve opening on the air supply pipeline), so as to determine the combustion air distribution under different fuel amounts, that is, determine the excess air coefficient, and then draw an air-oil configuration curve based on the obtained fuel amount and air volume data, that is, set a flue gas flow that changes linearly with the combustion rate; finally, the corresponding fuel air distribution can be obtained from the curve according to the target flue gas flow.

[0038] In the present invention, the cold air of the three-stage cooling element is led out from the blower outlet of the combustion system. The two-stage cooling element 3 and the three-stage cooling element play a role in fine-tuning the flue gas temperature, so that the difference between the flue gas temperature and the target temperature is within 5°C. Through this precise feedback control, the amount of cold air added is minimized to avoid affecting the flue gas composition.

[0039] In the present invention, the third smoke temperature sensor disposed at the chimney 7 outlet is used to monitor the smoke temperature, and then the first, second and third stage cooling components are used to perform closed-loop feedback control according to the smoke temperature.

[0040] Example Combined with the exhaust parameters of common marine power plants, a marine power plant exhaust simulation verification device is designed. The smoke indicators of the marine power plant exhaust simulation verification device include: exhaust flow range of 2kg / s to 10kg / s, temperature range of 290℃ to 550℃, and smoke temperature control error within 5℃.

[0041] To obtain a specified flow of flue gas, it is necessary to control the amount of fuel and air entering the combustion chamber 1, that is, to adjust the flue gas flow by controlling the amount of fuel and the air distribution. According to the law of conservation of mass and from the thermodynamic calculation, the amount of air required for 1kg of diesel when the excess air coefficient is 1.16 is 12.47Nm 3(equivalent to 15.03kg), then under this condition, to get 10kg / s of flue gas volume, the required fuel volume is (10kg / s×3600s / h / 16.03=)2246kg / h; that is, the burner needs to have the ability to completely burn 2246kg / h of fuel and be able to achieve linear proportional regulation. The heat generated by the complete combustion of 2246kg / h of fuel is (2246kg / h×40820kJ / kg=)91681720kJ / h, and the heat brought by the high-temperature flue gas at a flue gas temperature of 550℃ is (2246kg / h×10611kJ / kg=)23832306kJ / h, that is, 67849414kJ / h of heat must be taken away by the steam-water system, and the rated steam volume is calculated to be 23705kg / h. Similarly, when the flue gas flow rate is required to be 2kg / s, that is, the burner is required to handle a 20% combustion rate, but the excess air coefficient at this combustion rate is slightly higher than that at full load, taking 1.3, then the fuel volume is 403kg / h. Similarly, in order to keep the flue gas temperature at 290℃, the steam volume that takes away heat is calculated to be 5008kg / h.

[0042] The above are the calculation data of two extreme working conditions. The flue gas flow rate within this range can be adjusted by the amount of fuel oil and the amount of air supply. In actual operation, the amount of fuel oil and air supply is pre-set at a combustion rate of 20% to 100%, so that different combustion rates correspond linearly to the flue gas flow rate. It can also be seen from the above description that the flue gas temperature depends on the heat taken away by the steam, so the steam amount can be adjusted within the range of 5t / h to 25t / h (that is, by adjusting the amount of cooling water) to adjust the flue gas temperature. Of course, since the excess air volume and the output of saturated steam in actual operation will affect the flue gas temperature, the flue gas temperature is first adjusted to a value close to the target value and slightly higher than the target value during the design and system setting, and then a small amount of cold air output by the combustion blower is used to adjust the air and mix it into the high-temperature flue gas to obtain a more accurate flue gas temperature.

[0043] The above shows that the test parameters of flue gas temperature between 550℃~290℃ and flue gas volume of 10kg / s~2.0kg / s can be obtained by adjusting the combustion rate and steam temperature between the rated working condition and the minimum working condition, and high-temperature flue gas of various parameters in this range can be obtained. Other parameters such as operating water supply can be obtained by calculation.

[0044] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0045] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A smoke acquisition system for a ship power plant exhaust simulation test, characterized in that: It includes a combustion chamber, a smoke exhaust pipe, a chimney, and at least one temperature reducing element; A burner is arranged in the combustion chamber, and the burner is connected to a fuel supply pipeline and an air supply pipeline; the top outlet of the burner is connected to the lower end of the smoke exhaust pipe above; The upper end of the smoke exhaust pipe is connected to the chimney; The temperature reducing element is arranged inside the burner or the smoke exhaust pipe, and the inlet of the temperature reducing element is connected with the water supply pipeline; A smoke temperature sensor is arranged at the outlet of the chimney.

2. The flue gas acquisition system according to claim 1, characterized in that: The flue gas acquisition system includes a primary cooling component and a secondary cooling component; The primary cooling element and the secondary cooling element are respectively arranged inside the combustion chamber from bottom to top, and the inlets of the primary cooling element and the secondary cooling element are respectively connected to the water supply pipeline; The outlet of the first-stage cooling element is communicated with the inlet end of the second-stage cooling element through a pipeline.

3. The flue gas acquisition system according to claim 1, characterized in that: The flue gas acquisition system also includes a three-stage cooling element, the outlet end of which is connected to the inside of the smoke exhaust pipe; smoke temperature sensors are respectively arranged in the smoke exhaust pipe upstream and downstream of the outlet end of the three-stage cooling element.

4. The flue gas acquisition system according to any one of claims 1 to 3, characterized in that: The fuel supply pipeline is provided with a fuel regulating valve, and the air supply pipeline is provided with an air regulating valve and a blower.

5. The smoke acquisition system according to claim 2, characterized in that: The primary cooling element is a primary cooling coil, and the secondary cooling element is a secondary cooling coil.

6. The smoke acquisition system according to claim 5, characterized in that: The inlet ends of the primary cooling coil and the secondary cooling coil are respectively connected to the water supply pipeline; the outlet of the primary cooling coil is connected to the outlet pipeline, a steam-water separator is arranged on the outlet pipeline, the steam outlet of the steam-water separator is connected to the inlet of the secondary cooling coil through the steam pipeline, and the outlet of the secondary cooling coil is connected to the steam exhaust pipeline.

7. The smoke acquisition system according to claim 5, characterized in that: A water pump and a water valve are arranged on the water supply pipeline, and a buffer ball is arranged on the downstream pipeline of the water pump.

8. The flue gas acquisition system according to claim 3, characterized in that: The three-stage cooling component is a cold air pipeline, the outlet of the cold air pipeline is connected to the inside of the smoke exhaust pipe, and a cold air valve is arranged on the cold air pipeline; the inlet of the cold air pipeline is connected to the air supply pipeline.

9. A method for obtaining smoke for a smoke exhaust verification test of a ship power plant, characterized in that: The method is; Providing the smoke acquisition system of claim 1, and determining the flow rate and temperature of the target smoke; According to the target flue gas flow rate, calculate the fuel quantity of the burner, and then determine the fuel pressure and the opening of the fuel regulating valve; Distribute air according to the amount of fuel in the burner, obtain the air volume under the target flue gas flow rate, and determine the opening of the air regulating valve on the air supply pipeline; Ignition and combustion generate smoke, and at the same time the water valve on the water supply pipeline opens to supply cooling water to the primary and secondary cooling components respectively; the cold air pipeline supplies cold air to the exhaust pipe; The cooling water in the first-stage cooling element exchanges heat with the flue gas through radiation convection and radiation heat exchange, so that the difference between the flue gas temperature passing through the first-stage cooling element and the target temperature is less than 15°C; the cooling water in the first-stage cooling element absorbs heat and turns into steam, which generates saturated steam after passing through the steam-water separator, and then the saturated steam is sent to the second-stage cooling element at the top of the combustion chamber to absorb heat, and at the same time, feed water is added to further reduce the exhaust gas temperature after heat exchange with the flue gas; Detect the flue gas temperature at the entrance of the smoke exhaust pipe. When the difference between the flue gas temperature and the target temperature is detected to be less than 5°C, close the air valve in the cold air duct. When the flue gas temperature is detected to be more than 5°C higher than the target temperature, calculate the amount of cold air required to reduce the flue gas to the target temperature and adjust the opening of the air valve to perform three-level cooling on the flue gas in the smoke exhaust pipe until the third smoke temperature sensor at the chimney outlet detects that the temperature of the smoke gas has dropped to the target temperature.

10. The flue gas acquisition method according to claim 5, characterized in that: The specific method of air distribution according to the fuel quantity of the burner is as follows: determine the fuel quantity under the maximum flow condition and the minimum flow condition according to the flue gas flow range of the ship power unit, determine the fuel pressure and the opening of the fuel regulating valve, and under the ignition state, determine the air damper opening of each set point according to the oxygen content of the flue gas detected by the flue gas analyzer, so as to determine the combustion air distribution under different fuel quantities, that is, determine the excess air coefficient, and then draw the air-oil configuration curve according to the obtained fuel quantity and air volume data, that is, set a flue gas flow that changes linearly with the combustion rate; finally, the corresponding fuel air distribution can be obtained from the curve according to the target flue gas flow.

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