A boiler water thermal power deoxidization waste heat utilization based burner cooling water system

Abstract

The utility model discloses a kind of based on boiler water thermal power deaerating waste heat utilization's burner cooling water system, including cooling water storage tank and burner, it is characterized in that, desalted water is sent into closed cooling water storage tank as cooling medium, circulation is established by cooling water pump, it is pumped to the burner from cooling water storage tank, and desalted water is returned to the cooling water storage tank after heat exchange with burner by liquid separator tank;The cooling water storage tank gas phase outlet is connected with steam ejector, steam generated by boiler water thermal power deaerating is as the injection gas source of the steam ejector, desalted water returned to the cooling water storage tank is partially evaporated under vacuum, and after the evaporated desalted water and injected steam are mixed, it enters boiler water deaerator.The mouth cooling water system can reduce energy consumption, reduce resource waste, improve safety, provide a kind of efficient, safe, environmentally friendly burner cooling scheme for coal chemical industry.

Description

Technical Field

[0001] This utility model belongs to the field of coal chemical technology, specifically relating to a burner cooling water system based on the utilization of waste heat from boiler hydrothermal deaeration. Background Technology

[0002] In the field of coal chemical industry (such as coal gasification, coal-to-oil, and coal-to-olefins), the gasifier burner is one of the core pieces of equipment. Its function is to efficiently mix and combust raw materials such as pulverized coal, oxygen, and steam. Because the burner is in a high-temperature, high-pressure, and highly corrosive environment for a long time, the stable operation of its cooling system is directly related to the safety, reliability, and economy of the burner itself, the gasifier, and even the entire production plant.

[0003] The key functions of a burner cooling water system include cooling protection, temperature control, and safety interlocks. Cooling protection involves circulating cooling water to remove heat from the high-temperature zone of the burner, preventing overheating and damage to the metal materials. Temperature control maintains the burner within a reasonable operating temperature range, avoiding structural failure caused by localized overheating or thermal stress. Safety interlocks are triggered by abnormalities in the cooling water system (such as low flow rate, high temperature, or abnormal pressure) to shut down the system and prevent burner burnout or explosion.

[0004] The burner cooling water technologies widely used in the coal chemical industry mainly include the following methods: (1) Open-loop cooling system (currently the most common method, cooling with circulating water) The technical characteristic of this cooling water system is that the cooling water absorbs heat from the burners and then exchanges heat with the circulating water, which then returns to the open cooling tower for heat dissipation and reuse. The main problem is that the circulating cooling water is exposed to the atmosphere and is easily contaminated (e.g., by dust, oxygen), leading to increased risk of corrosion and scaling in the burner cooling water heat exchanger. Heat is directly lost, resulting in low energy efficiency, and water pollution may affect the burner's lifespan.

[0005] (2) Closed-loop cooling system (mechanical vacuum pressure control) This cooling water system uses demineralized water as the cooling medium, circulating in a closed system. An electrically driven vacuum pump maintains negative pressure, causing partial evaporation and cooling of the high-temperature return water under low pressure. The main problems are: high energy consumption during long-term operation of the vacuum pump, and susceptibility to mechanical failure, affecting system stability; direct discharge of evaporated water vapor, resulting in waste of water and heat; and the lack of rapid detection methods in case of burner leaks (such as CO or other combustible gases entering the cooling water), posing a safety hazard.

[0006] In summary, the main defects of existing burner cooling water systems are high energy consumption, insufficient safety, and waste of resources. These include high power consumption and low energy efficiency due to continuous operation of the mechanical vacuum pump; lack of rapid detection and emergency measures for burner leaks (such as CO entering the cooling water); ineffective recovery of evaporated water and heat, increasing operating costs; leakage and corrosion of the circulating water heat exchanger; and energy consumption of the circulating water. Summary of the Invention

[0007] The purpose of this invention is to provide a burner cooling water system based on the utilization of waste heat from boiler hydrothermal deaeration, which solves the problems of high energy consumption, low safety and resource waste in existing burner cooling water systems, and provides an efficient, safe and environmentally friendly burner cooling solution for the coal chemical industry.

[0008] To achieve the above-mentioned objectives, this utility model provides a burner cooling water system based on the utilization of waste heat from boiler water thermal deaeration, comprising a cooling water storage tank and burners. The system is characterized in that demineralized water is fed into a sealed cooling water storage tank as a cooling medium, and a circulation is established by a cooling water pump. The demineralized water is pumped from the cooling water storage tank to the burners, and after heat exchange with the burners, it returns to the cooling water storage tank via a separator. The vapor outlet of the cooling water storage tank is connected to a steam ejector, and the steam used for boiler water thermal deaeration serves as the injection gas source for the steam ejector. The demineralized water returning to the cooling water storage tank partially evaporates under vacuum, and the evaporated demineralized water mixes with the injected steam before entering the boiler water deaerator.

[0009] Furthermore, the vapor outlet of the cooling water storage tank is also connected to a vacuum pump, and the exhaust gas from the vacuum pump is connected to the boiler water deaerator.

[0010] Furthermore, an online CO monitor is installed at the vapor outlet of the cooling water storage tank to determine whether there is a leak during burner operation.

[0011] Furthermore, a condenser is installed before the gas inlet of the CO online monitoring instrument.

[0012] Furthermore, the cooling water storage tank is equipped with a vacuum gauge.

[0013] Beneficial Effects: This utility model's burner cooling water system based on boiler water thermal deaeration and waste heat utilization utilizes low-pressure steam (0.5MPa) from the boiler deaeration system in its steam ejector, improving energy utilization efficiency. Online CO monitoring can be integrated with interlocking protection; a condensing online CO monitor is installed in the gas phase pipeline to ensure timely alarm and action in case of leakage. Evaporated cooling water is mixed with steam and recycled to the boiler water deaerator, achieving efficient recovery of water and heat. Dual redundancy control of the steam ejector and electric vacuum pump improves system reliability. Specifically, it includes: 1. Unaffected by ambient temperature, precise temperature control: The evaporation rate and temperature are controlled by the pressure of the cooling water storage tank for the control burner; 2. The coolant tank is sealed, making burner leak detection more sensitive and reducing interference from external factors; 3. Use the steam from boiler water thermal deoxygenation as the injection gas source, mix it with the evaporated demineralized water and enter the deaerator to achieve secondary utilization of demineralized water and heat; 4. No circulating water cooler is required, reducing equipment corrosion and leakage, and saving circulating water volume. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an existing burner cooling water system. Among them, 1. Cooling water storage tank, 2. Cooling water pump, 3. Circulating water cooler, 4. Burner, 5. Separator, 6. CO online monitor; Figure 2 This is a schematic diagram of a burner cooling water system based on the utilization of waste heat from boiler water thermal deaeration. The components include: 1. Cooling water storage tank; 2. Cooling water pump; 4. Burner; 5. Separator; 6. CO online monitor; 7. Steam ejector; 8. Vacuum pump; and 9. Boiler water deaerator. Detailed Implementation

[0015] The technical solution of this utility model will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of this utility model.

[0016] Existing burner cooling water systems, such as Figure 1 Cooling water in the atmospheric pressure cooling water storage tank 1 is circulated by cooling water pump 2. The water is first pumped to the circulating water cooler 3 for heat dissipation, then sent to the burner 4 for heat exchange before returning to the cooling water storage tank 1 via the separator 5 for reuse. An online CO monitor 6 is installed at the gas phase outlet of the separator 5 to sample and analyze the CO before venting.

[0017] like Figure 2A burner cooling water system based on the utilization of waste heat from boiler water thermal deaeration is disclosed. The cooling medium, demineralized water, is fed into a cooling water storage tank 1 and then pumped to burners 4 by a cooling water pump 2. After heat exchange with burners 4, the demineralized water returns to the cooling water storage tank 1 via a separator 5, establishing a demineralized water circulation. The cooling water storage tank 1 is a sealed container maintaining a certain vacuum. Its vapor phase outlet pipe is connected to a steam ejector 7, which uses steam generated from boiler water thermal deaeration as the injection gas source. A CO online monitoring instrument 6 with a condenser is installed on the vapor phase pipe at the inlet of the steam ejector 7. The steam injection generates negative pressure, causing partial evaporation of the demineralized water returning to the cooling water storage tank 1 under vacuum. The evaporated demineralized water mixes with the injected steam and enters the boiler water deaerator 9. A vacuum pump 8 is also connected in parallel to the vapor phase outlet pipe of the cooling water storage tank 1, and the exhaust gas from the vacuum pump 8 is connected to the boiler water deaerator 9.

[0018] After the demineralized water that has been heated after cooling burner 4 returns to the cooling water storage tank 1, the latent heat of vaporization carried away by some of the evaporation maintains the heat balance of the cooling water system. A pressure gauge is installed on the cooling water storage tank 1, and the pressure (vacuum) of the cooling water storage tank 1 is adjusted according to the operating temperature requirements of the burner cooling water.

[0019] After the demineralized water cools the burner, it is heated and maintains thermal balance through its own evaporation. Taking a 10-degree increase in the temperature of 300 tons of cooling water, from 35°C to 45°C, as an example, to control the pressure to 9.6 kPa (saturation pressure at 45°C), approximately 5.25 tons of water need to be evaporated to maintain the system's thermal balance. At the same time, the burner cooling water system is sealed to maintain this pressure.

[0020] 0.5MPa steam from boiler water thermal deaeration is used as the gas source for the steam ejector 7 on the vapor phase pipeline at the top of the cooling water storage tank 1 of the burner cooling system, controlling the pressure corresponding to the return water temperature of the burner 4 (45 degrees corresponds to a pressure of 9.6kPa). An electrically driven vacuum pump 8 serves as a backup. The evaporated demineralized water mixes with the injected steam and enters the boiler water deaerator 9 to recover water and heat. A CO online monitoring instrument 6 with condensation function is installed on the vapor phase pipeline at the inlet of the steam ejector 7 to determine if there is a leak during the operation of the burner 4. A cooling water pump 2 is installed at the bottom of the cooling water storage tank 1 (note the pump's installation height and the liquid level control in the cooling water storage tank 1 to avoid pump cavitation). The cooling water temperature rises after passing through the burner shroud and returns to the cooling water storage tank 1, where it cools down by evaporation due to pressure reduction, completing the circulation.

[0021] First, the demineralized water circulation between cooling water storage tank 1, cooling water pump 2, and burner 4 is established through cooling water pump 2. Second, the vapor phase pressure control is established through steam ejector 7 (vacuum pump 8 can be used if the downstream system is not started). After the gasifier is running, the pressure of cooling water storage tank 1 is reduced to 9.6 kPa by increasing the steam flow of steam ejector 7 (or the corresponding pressure is adjusted according to the operating temperature requirements of the burner cooling water). The evaporated demineralized water and steam are mixed and enter the boiler water deaerator 9. After thermal deaeration, it is sent to the downstream boiler, steam boiling boiler, etc.

[0022] During operation, the CO online monitoring instrument 6 normally reads 0. If an alarm is triggered, a retest can be performed through the vent of the boiler water deaerator 9. If a leak is confirmed in burner 4, the system can be monitored or the system can be shut down for handling.

[0023] The burner cooling water system described above uses pressure-controlled evaporative cooling combined with steam jet waste heat recovery, offering the following advantages compared to traditional burner cooling water technology: 1. Precise temperature control, unaffected by ambient temperature. Traditional systems relying on mechanical vacuum pumps or external coolers suffer from significant temperature fluctuations due to variations in ambient temperature and cooling water flow. This system, however, precisely controls evaporation by adjusting the cooling water tank pressure (e.g., 9.6 kPa for 45℃), ensuring the return water temperature remains stable at the set value (e.g., 45℃ ± 1℃), unaffected by seasonal or ambient temperature changes.

[0024] 2. Closed system + CO monitoring significantly improves safety. Open systems are susceptible to contamination, while closed systems suffer from delayed leak detection. This system features a fully enclosed loop, preventing the entry of oxygen and dust and reducing the risk of corrosion. A condensing online CO monitor is installed on the vapor phase pipeline to quickly identify burner leaks (such as CO mixing with cooling water). Small amounts of CO leaking into the boiler water deaerator can be removed thermally; large leaks trigger an interlock shutdown to prevent explosions.

[0025] 3. Utilizing waste heat steam from boiler deaeration significantly reduces energy consumption and emissions. Unlike steam ejectors, which require an external supply of high-pressure steam (e.g., 10 kg or more) or rely on an electrically driven vacuum pump (which consumes a lot of energy), this system uses the boiler water deaerator's own 5 kg of low-pressure steam as the injection gas source, requiring no additional energy. The evaporated demineralized water is mixed with the injection steam and returned to the deaerator, achieving 100% water and heat recovery, reducing makeup water consumption and boiler fuel consumption.

[0026] 4. Eliminate the circulating water cooler to reduce equipment maintenance. The use of plate / tube heat exchangers with secondary cooling via circulating water poses risks of scaling, corrosion, and leakage. This system replaces mechanical cooling with evaporative cooling, eliminating the need for a circulating water cooler and saving circulating water volume (e.g., 200–400 m³ / h). It also reduces the investment in moving equipment (such as cooling water pumps) and chemical agents (such as corrosion inhibitors), lowering maintenance costs.

[0027] The burner cooling water system based on boiler hydrothermal deaeration and waste heat utilization is calculated as follows, assuming the burner cooling circulating water temperature rises by 10℃, with different circulating water volumes (200 / 300 / 400 m³ / h):

[0028] Note: Heat absorption calculation: Q = m·cp·ΔT (m is the flow rate, specific heat capacity cp = 4.18 kJ / kg·℃, ΔT = 10℃); Evaporation estimation: Based on a latent heat of vaporization of approximately 2,390 kJ / kg, evaporation ≈ heat absorbed / latent heat of vaporization; Steam (5kg) consumption: The efficiency of the steam ejector is estimated at 1:8 (steam: air extraction).

[0029] Based on the table above, the overall benefits are summarized as follows: Energy saving: Utilizing waste heat steam reduces the power consumption of vacuum pumps (approximately 50–100 kW / unit) and the amount of circulating water used.

[0030] Water saving: Closed-loop circulation + evaporation recovery reduces the amount of desalinated water replenished (1,000–2,000 kg / h).

[0031] Safety: Real-time CO monitoring and interlock protection prevent accidents caused by burner leaks.

[0032] Stable: Dual vacuum sources (steam jet + vacuum pump backup) ensure uninterrupted pressure control.

[0033] The burner cooling water system described herein is suitable for high-temperature burner cooling systems in industries such as coal chemical, metallurgy, and glass, and is especially suitable for operating conditions with high flow rates (above 200 m³ / h) and high reliability requirements.

Claims

1. A burner cooling water system based on boiler hydrothermal deaeration waste heat utilization, comprising a cooling water storage tank and burners, characterized in that, Demineralized water is fed into a sealed cooling water storage tank as a cooling medium. A cooling water pump establishes a circulation, and the water is pumped from the cooling water storage tank to the burner. After exchanging heat with the burner, the demineralized water is returned to the cooling water storage tank via a separator. The vapor outlet of the cooling water storage tank is connected to a steam ejector. Steam generated by the boiler water thermal deaeration serves as the injection gas source for the steam ejector. The demineralized water returning to the cooling water storage tank partially evaporates under vacuum. The evaporated demineralized water mixes with the injected steam and then enters the boiler water deaerator.

2. The burner cooling water system according to claim 1, characterized in that, The cooling water storage tank's gas phase outlet is also connected to a vacuum pump, and the exhaust gas from the vacuum pump is connected to the boiler water deaerator.

3. The burner cooling water system according to claim 1, characterized in that, An online CO monitor is installed at the vapor phase outlet of the cooling water storage tank.

4. The burner cooling water system according to claim 3, characterized in that, A condenser is installed before the gas inlet of the CO online monitoring instrument.

5. The burner cooling water system according to claim 1, characterized in that, The cooling water storage tank is equipped with a vacuum gauge.

Images