Leakage monitoring system for sintering large flue water tube type waste heat boiler

Abstract

This utility model relates to the field of waste heat recovery and discloses a leakage monitoring system for a sintering flue water-tube waste heat boiler. The system includes a steam drum and multiple heat exchangers connected to the steam drum within the sintering flue. At least one heat exchanger serves as an evaporator, with its inlet and outlet connected to the steam drum via downcomers and risers, respectively. The inlet of at least one heat exchanger is connected to the steam drum via a first steam pipe, and its outlet is connected to the external steam network via a second steam pipe, serving as a superheater. Laser flue gas humidity analyzers are installed on both sides of each heat exchanger within the sintering flue to monitor the flue gas humidity on both sides of each heat exchanger in real time. This utility model enables timely identification and isolation of leaking heat exchange modules when leaks occur within the sintering flue, ensuring the safe operation of the sintering machine and preventing low-temperature corrosion of subsequent heat exchange surfaces due to leakage.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery, and in particular to a leakage monitoring system for a sintering large flue water tube type waste heat boiler. Background Technology

[0002] Currently, large-scale ferrous metallurgical sintering plants use sintering machines for sintering operations. These machines can sinter concentrates and rich ore powders of different compositions and particle sizes into blocks, and partially eliminate harmful impurities such as sulfur and phosphorus contained in the ore. The high-temperature flue gas generated during sintering is drawn into the main flue of the sintering machine by a fan. The temperature of each air box in the main flue is approximately 200–500℃. To recover and utilize this waste heat from the flue gas, water-tube waste heat boilers are commonly used. This involves installing heat exchangers in the main flue to absorb the heat from the flue gas and generate steam for external use or for waste heat power generation.

[0003] Because the flue gas from the sintering flue contains a high dust content and sulfur dioxide, and the temperature of each air box in the flue can fluctuate significantly, especially with changes in ore and adjustments to the sintering process, the heat exchange surfaces of the waste heat boiler may experience wear and low-temperature corrosion, potentially leading to tube rupture after a period of operation. When the leakage in the heat exchange tubes is small, the water directly absorbs heat and evaporates within the flue, making it difficult for operators to accurately determine the leak status using temperature measurement points before and after the heat exchange module. Increased moisture content in the flue gas lowers the acid dew point, potentially causing further corrosion and damage to subsequent boiler heat exchange pipes. Therefore, how to monitor leaks in the sintering flue water-tube waste heat boiler, ensuring timely detection and isolation of even minor leaks, and thus guaranteeing the safe operation of the sintering machine process system, is a common concern across the industry. Utility Model Content

[0004] This utility model aims to solve the technical problems existing in the prior art. To this end, this utility model provides a leakage monitoring system for a sintering flue water-tube waste heat boiler, which can promptly identify and isolate the leaking heat exchange module when a leak occurs in the heat exchanger within the sintering flue, ensuring the safe operation of the sintering machine and preventing low-temperature corrosion of subsequent heat exchange surfaces caused by leakage.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A leakage monitoring system for a sintering flue water-tube waste heat boiler is provided, comprising a steam drum and multiple heat exchangers connected to the steam drum within the sintering flue; at least one heat exchanger serves as an evaporator, with its inlet and outlet connected to the steam drum via downcomers and risers, respectively; the inlet of at least one heat exchanger is connected to the steam drum via a first steam pipe, and its outlet is connected to an external steam network via a second steam pipe, serving as a superheater; laser flue gas humidity analyzers are installed on both sides of each heat exchanger within the sintering flue to monitor the flue gas humidity on both sides of each heat exchanger in real time.

[0007] In some optional embodiments, temperature measuring devices and pressure measuring devices are respectively installed on both sides of each heat exchanger in the sintering flue, for real-time monitoring of the flue gas temperature and pressure on both sides of each heat exchanger in the sintering flue.

[0008] In some optional embodiments, the sintering flue is also equipped with an online sulfur dioxide analyzer for real-time monitoring of the sulfur dioxide concentration in the sintering flue.

[0009] In some alternative implementations, each heat exchanger is equipped with an isolation valve at both the inlet and outlet ends.

[0010] In some alternative embodiments, a bypass pipe is provided between the first steam pipe and the second steam pipe, and a bypass valve is provided on the bypass pipe.

[0011] In some alternative implementations, both the isolation valve and the bypass valve are electrically operated.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. This utility model can use a laser flue gas humidity analyzer to monitor the flue gas humidity before and after each heat exchanger in real time, and can accurately identify the leaking heat exchanger based on the increase in flue gas humidity, so as to isolate the heat exchanger in time.

[0014] 2. The system can also use temperature and pressure measuring devices to monitor the flue gas temperature and pressure before and after each heat exchanger in real time. On the one hand, it can provide guidance for safe production operation. On the other hand, combined with the flue gas humidity monitored by the laser flue gas humidity analyzer, it can dynamically reflect the leakage amount of a single heat exchanger based on the moisture content of the flue gas when a heat exchanger leak occurs, and realize quantitative analysis of the damage of a single heat exchanger.

[0015] 3. The system's online sulfur dioxide analyzer, combined with a laser flue gas humidity analyzer, can calculate the flue gas acid dew point temperature. This enables the isolation of leaking heat exchangers in cases of large leaks or low-temperature corrosion, ensuring the safe operation of the sintering machine and waste heat boiler. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0017] Figure 1 This is a structural diagram of the leakage monitoring system for a sintering large flue water tube type waste heat boiler provided by this utility model.

[0018] The attached diagram lists the components represented by each number as follows:

[0019] 1—Steam drum, 2—Heat exchanger, 2a—Evaporator, 2b—Superheater, 3—Isolation valve, 4—Bypass pipe, 5—Bypass valve, 6—Laser flue gas humidity analyzer, 7—Temperature measuring device, 8—Pressure measuring device, 9—Sulfur dioxide online analyzer, 10—Sintering flue. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0022] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] Furthermore, the terms "first," "second," etc., used in this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. The terms "installed," "connected," and "joined" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0025] Example 1

[0026] As attached Figure 1 As shown, this embodiment provides a leakage monitoring system for a sintering flue water-tube waste heat boiler, including a steam drum 1 and multiple heat exchangers 2 located within the sintering flue 10 and connected to the steam drum 1. Preferably, the inlet and outlet of at least one heat exchanger 2 are connected to the steam drum via downcomers and risers, respectively, serving as an evaporator 2a; the inlet of at least one heat exchanger 2 is connected to the steam drum via a first steam pipe, and the outlet is connected to the external steam network via a second steam pipe, serving as a superheater 2b. Boiler water enters the evaporator from the steam drum through the downcomer to absorb heat. After absorbing heat, the boiler water becomes a steam-water mixture and enters the steam drum through the riser. The saturated steam in the steam drum enters the superheater through the first steam pipe to continue absorbing heat, becoming superheated steam for use by the external steam network.

[0027] Preferably, in this embodiment, an isolation valve 3 is provided at the inlet and outlet ends of each heat exchanger 2 to facilitate isolation of the heat exchanger in case of leakage. After isolation of the heat exchanger, the steam in the steam drum needs to be discharged. Therefore, in this embodiment, a bypass pipe 4 is also provided between the first steam pipe and the second steam pipe, and a bypass valve 5 is installed on the bypass pipe to allow the steam in the steam drum to be directly sent to the external steam network through the bypass pipe after the superheater is isolated. In this embodiment, the isolation valve and bypass valve are preferably electric valves for easy automatic control.

[0028] To accurately determine whether a heat exchanger is leaking, this embodiment installs laser flue gas humidity analyzers 6 (selectable from the Noco Instruments NK-300 series) on both sides of each heat exchanger within the sintering flue. These analyzers monitor the flue gas humidity on both sides of each heat exchanger in real time. Working principle: When there is no leak in the heat exchanger, the humidity readings of the flue gas before and after the leak are consistent. When a leak occurs, some furnace water leaks into the flue gas and evaporates, increasing the flue gas humidity. The leaking heat exchanger can be identified by the change in the values ​​measured by the laser flue gas humidity analyzers before and after the leak, and the leak can be isolated by closing the isolation valves at the inlet and outlet of that heat exchanger.

[0029] Example 2

[0030] Based on Embodiment 1, this embodiment further provides temperature measuring devices 7 and pressure measuring devices 8 on both sides of each heat exchanger in the sintering flue, respectively, for real-time monitoring of the flue gas temperature and pressure on both sides of each heat exchanger in the sintering flue.

[0031] This embodiment utilizes temperature and pressure measuring devices to monitor the flue gas temperature and pressure before and after each heat exchanger in real time. On one hand, this provides guidance for safe production operation; on the other hand, combined with flue gas humidity monitoring by a laser flue gas humidity analyzer, it can dynamically reflect the leakage amount of a single heat exchanger based on the moisture content of the flue gas when a leak occurs (the higher the moisture content, the greater the leakage), enabling quantitative analysis of the damage to individual heat exchangers. The formula for calculating the moisture content of the flue gas before and after the heat exchanger is as follows:

[0032]

[0033] In the formula: d is the moisture content; The relative humidity of the flue gas (measured by a laser flue gas humidity analyzer); P s Let be the saturated humidity of the flue gas (which can be calculated using thermodynamic formulas or by consulting a water vapor table; for example, the saturated water vapor pressure at 50℃ is approximately 12.3 kPa, meaning the saturated humidity of the flue gas at 50℃ is 12.3 kPa); and P be the flue gas pressure (measured by a pressure measuring device). The above formula is a well-known existing formula; for details, please refer to "Engineering Thermodynamics," Machinery Industry Press.

[0034] Example 3

[0035] Based on Example 1 or Example 2, this example further includes an online sulfur dioxide analyzer 9 (THA100 type) installed in the sintering flue 10 to monitor the concentration of sulfur dioxide in the sintering flue in real time.

[0036] This embodiment can calculate the acid dew point temperature of flue gas based on data from an online sulfur dioxide analyzer and a laser flue gas humidity analyzer. The specific calculation formula is as follows:

[0037]

[0038] In the formula: t dew This refers to the acid dew point temperature of the flue gas. The percentage (%) of flue gas water vapor. This represents the percentage (%) of SO2 in the flue gas. The above formula is a well-known, existing formula, where... The percentage of water vapor in the flue gas can be calculated from the data measured by the laser flue gas humidity analyzer.

[0039] This embodiment enables the system to operate normally when the leakage is small and the operating temperature is higher than the acid dew point temperature; when the leakage is large or low-temperature corrosion occurs, the leaking heat exchanger can be isolated by the isolation valves installed on the inlet and outlet pipes of the heat exchanger, ensuring the safe operation of the sintering machine and the waste heat boiler.

[0040] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A leakage monitoring system for a sintering flue water-tube waste heat boiler, comprising a steam drum and multiple heat exchangers connected to the steam drum within the sintering flue; characterized in that: At least one heat exchanger has its inlet and outlet connected to the steam drum via downcomers and risers, respectively, serving as an evaporator; the inlet of at least one heat exchanger is connected to the steam drum via a first steam pipe, and its outlet is connected to the external steam network via a second steam pipe, serving as a superheater. Laser flue gas humidity analyzers are installed on both sides of each heat exchanger in the sintering flue to monitor the flue gas humidity on both sides of each heat exchanger in the sintering flue in real time.

2. The leakage monitoring system for a sintering large flue water-tube waste heat boiler according to claim 1, characterized in that: Temperature measuring devices and pressure measuring devices are installed on both sides of each heat exchanger in the sintering flue, respectively, to monitor the flue gas temperature and pressure on both sides of each heat exchanger in the sintering flue in real time.

3. The leakage monitoring system for a sintering large flue water-tube waste heat boiler according to claim 1, characterized in that: The sintering flue is also equipped with an online sulfur dioxide analyzer to monitor the concentration of sulfur dioxide in the sintering flue in real time.

4. The leakage monitoring system for a sintering large flue water-tube waste heat boiler according to any one of claims 1 to 3, characterized in that: Each heat exchanger is equipped with an isolation valve at both the inlet and outlet ends.

5. The leakage monitoring system for a sintering large flue water-tube waste heat boiler according to claim 4, characterized in that: A bypass pipe is also provided between the first steam pipe and the second steam pipe, and a bypass valve is provided on the bypass pipe.

6. The leakage monitoring system for a sintering large flue water-tube waste heat boiler according to claim 5, characterized in that: Both the isolation valve and the bypass valve are electric valves.

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