Anti-condensation device for steam soot-blowing residual pressure energy utilization

Abstract

The utility model belongs to a kind of steam soot-blowing residual pressure energy utilization's anti-condensation device;Including low-temperature superheater and hot primary air pipeline, the low-temperature superheater steam outlet is connected with turbine, and the outlet of turbine is connected with through temperature pressure detection unit and temperature compensation unit and soot-blowing pipeline;The mechanical end of the turbine is connected with generator;The inside of the turbine is connected with the nozzle valve of nozzle;The hot primary air pipeline is connected with temperature compensation unit. Through setting the technical scheme that turbine and temperature compensation unit cooperate, to realize the recovery of steam energy from low-temperature superheater, while realizing energy recovery, the temperature of low-temperature steam is compensated by temperature compensation unit, to meet the characteristics that superheat degree is greater than 80 DEG C, prevent condensation phenomenon in soot-blowing pipe, realize long time stable operation of soot-blowing system.

Description

Technical Field

[0001] This utility model belongs to the field of steam soot blowing technology, specifically an anti-condensation device for utilizing residual pressure energy in steam soot blowing. Background Technology

[0002] Soot blowing systems are an important component of boiler systems. Their primary task is to remove slag and ash buildup on heating surfaces, ensuring their cleanliness and thus guaranteeing safe boiler operation. Taking soot blowing on water-cooled walls as an example: slag or ash buildup on the water-cooled walls severely affects the furnace's heat absorption efficiency, reduces the boiler's evaporation rate, and leads to increased steam and tube wall temperatures in the superheater and reheater, potentially even causing overheating and tube rupture. Furthermore, ash buildup on the convection tube bundles not only reduces heat transfer efficiency but also increases flue gas heat loss and induced draft fan power consumption, and in severe cases, can even affect boiler output. This also increases boiler energy consumption and emissions.

[0003] Currently, the steam source for soot blowing is taken from the outlet of the low-temperature superheater (pressure: 9.8 MPa; temperature: 390℃). During steam soot blowing, a certain pressure and superheat must be maintained. For example, the pressure is generally controlled between 1.1 and 1.5 MPa. Excessive pressure will damage the equipment, leading to blown-off surfaces and tube rupture; insufficient pressure will not guarantee the soot blowing effect. Regarding superheat, the temperature must be greater than 80℃ when the steam reaches the sootblower nozzle. Insufficient temperature will cause the steam to condense into water droplets after entering the boiler. When the sootblower tube length exceeds 50 meters, the heat loss along the path further increases the probability of condensation. When the sootblower's drainage is poor, these water droplets will be carried onto the boiler's heating surface tube bundle, causing cracking and deformation due to temperature changes, ultimately leading to boiler tube rupture. Furthermore, when burning high-sulfur coal, condensate combines with ash to form sulfate scale, accelerating tube wall corrosion, and the repair cost for a single tube rupture exceeds 200,000 yuan. In summary, the steam pressure and temperature at the outlet of the low-temperature superheater are high, while the required pressure and temperature for soot blowing are relatively low. Some companies have attempted to recover this energy using turbines. When the steam pressure is reduced from 9.8 MPa to 1.1 MPa, the temperature of the steam drops sharply from 380℃ to 200-220℃ after isentropic expansion. The low-temperature steam at 200-220℃ will condense in the soot blowing tube, and water droplets impacting the heated surface can easily cause tube rupture. Based on this, companies currently use pressure reducing valves in their soot blowing systems. These valves use orifice plates for mechanical pressure reduction. After adiabatic expansion, the entropy of the 9.8 MPa steam increases by 0.8 kJ / (kg·K), resulting in a loss of approximately 1200 kJ / kg of usable energy. Furthermore, because the steam needs to be continuously depressurized, the pressure reducing valves are prone to damage. Utility Model Content

[0004] To overcome the above deficiencies, this utility model provides an anti-condensation device for utilizing residual pressure energy from steam soot blowing, thereby solving the technical problems existing in the prior art.

[0005] The technical solution adopted by this utility model to solve its technical problem is: An anti-condensation device for utilizing residual pressure energy in steam soot blowing includes a low-temperature superheater and a hot primary air duct. The steam outlet of the low-temperature superheater is connected to a turbine, and the outlet of the turbine is connected to the soot blowing duct via a temperature and pressure detection unit and a temperature compensation unit. The mechanical end of the turbine is connected to a generator. The interior of the turbine is connected to a nozzle valve connected to a nozzle. The hot primary air duct is connected to the temperature compensation unit.

[0006] The beneficial effects of this utility model are as follows: By using a turbine in conjunction with a temperature compensation unit, the energy of the steam can be recovered by the turbine. After recovery, when the temperature drops, the temperature compensation unit compensates for the temperature of the low-temperature steam to meet the requirements of the soot blowing system for steam temperature and pressure. In this utility model, a nozzle valve is used to adjust the opening of the nozzle to ensure that the steam is at 1.1~1.5Mpa, and the temperature and pressure detection unit monitors the temperature of the low-temperature steam. When compensation is needed, the temperature of the low-temperature steam can be compensated by the hot primary air in the hot primary air pipeline to prevent condensation in the soot blowing pipe.

[0007] Preferably, the temperature and pressure detection unit includes a first pressure sensor and a first temperature sensor installed on the pipe at the turbine outlet.

[0008] Preferably, the temperature compensation unit includes a gas-steam heat exchanger, and the turbine outlet is connected to the soot blowing pipe through the first channel and the third temperature sensor of the gas-steam heat exchanger; the hot primary air pipe is connected to the coal mill inlet of the coal pulverizing system through the second channel of the gas-steam heat exchanger.

[0009] Preferably, the hot primary air duct is provided with a first tee and a first valve, and a second tee is provided between the second channel of the gas-steam heat exchanger and the coal powder drying port of the coal mill in the coal pulverizing system. The third end of the first tee is connected to the third end of the second tee through the second valve.

[0010] Preferably, a fourth temperature sensor is provided between the second channel and the second and third channels of the gas-steam heat exchanger, and a fifth temperature sensor is provided between the second and third channels and the coal powder drying port of the coal mill.

[0011] Preferably, a flow meter, a second temperature sensor, and a second pressure sensor are sequentially installed between the steam outlet of the low-temperature superheater and the turbine.

[0012] This utility model also includes a PLC control system. The signal input terminals of the PLC control system are respectively connected to the first pressure sensor, the third temperature sensor, and the fifth temperature sensor. The signal output terminals of the PLC control system are connected to the nozzle valve, the first valve, and the second valve.

[0013] A steam soot blowing residual pressure energy utilization anti-condensation device, manufactured according to the above scheme, utilizes a turbine and a temperature compensation unit to recover steam energy from the low-temperature superheater. Simultaneously, the temperature compensation unit compensates for the temperature of the low-temperature steam to ensure a superheat greater than 80°C, preventing condensation within the soot blowing pipe and ensuring long-term stable operation of the soot blowing system. The temperature compensation unit includes a gas-steam heat exchanger, which compensates for the low-temperature steam through heat exchange between hot primary air and low-temperature steam. The hot primary air can compensate for the low-temperature steam according to actual conditions. It not only provides thermal compensation for the low-temperature steam but also compensates for the temperature of the hot primary air after heat exchange via a bypass pipe with a second valve, ensuring it is suitable for drying at the coal powder drying port of the coal mill. In other words, the temperature compensation unit of this invention can compensate for the temperature of both low-temperature steam and hot primary air, satisfying the soot blowing system requirements while avoiding modifications to the coal pulverizing system. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the control principle of this utility model.

[0017] In the diagram: 1. Low-temperature superheater; 2. Hot primary air duct; 3. Turbine; 4. Generator; 5. Soot blowing duct; 6. Nozzle; 7. Nozzle valve; 8. First pressure sensor; 9. First temperature sensor; 10. Gas-steam heat exchanger; 11. Third temperature sensor; 12. Coal mill; 13. First tee; 14. First valve; 15. Second tee; 16. Second valve; 17. Flow meter; 18. Second temperature sensor; 19. Second pressure sensor; 20. PLC control system; 21. Fourth temperature sensor; 22. Fifth temperature sensor. Detailed Implementation

[0018] 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.

[0019] The following is in conjunction with the appendix Figure 1 This application provides a further detailed description of an anti-condensation device for utilizing residual pressure energy in steam soot blowing. It includes a low-temperature superheater 1 and a hot primary air duct 2. The steam outlet of the low-temperature superheater 1 is connected to a turbine 3. The outlet of the turbine 3 is connected to the soot blowing duct 5 via a temperature and pressure detection unit and a temperature compensation unit. The mechanical end of the turbine 3 is connected to a generator 4. A nozzle valve 7 is connected to a nozzle 6 inside the turbine 3. The hot primary air duct 2 is connected to the temperature compensation unit. This invention is applied to a soot blowing system, enabling the safe and stable operation of the entire system while recovering the steam energy in the low-temperature superheater 1. Specifically, it recovers the steam energy through a turbine 3. When the pressure reaches the target threshold, the temperature of the recovered steam is compensated in a temperature compensation unit by the hot primary air from the hot primary air duct 2, thereby increasing the temperature of the low-temperature steam and preventing condensation in the soot blowing pipe. Furthermore, this invention regulates the steam pressure after passing through the turbine 3 through a nozzle valve 7 connected to the nozzle 6, keeping it within the pressure threshold range of 1.1 to 1.5 MPa. Simultaneously, a temperature and pressure detection unit can detect the pressure and temperature of the steam after passing through the turbine 3 in real time. After ensuring the steam pressure is within the aforementioned threshold range, the flow rate of the hot primary air in the temperature compensation unit is determined by the steam temperature value, thus ensuring the safe and stable operation of the soot blowing system.

[0020] Preferably, the temperature and pressure detection unit includes a first pressure sensor 8 and a first temperature sensor 9 installed on the pipe at the outlet of the turbine 3. The temperature and pressure detection unit of this invention includes a first pressure sensor 8 and a first temperature sensor 9 for detecting pressure after passing through the turbine 3, and for real-time monitoring of the pressure and temperature of the low-temperature steam.

[0021] Preferably, the temperature compensation unit includes a gas-vapor heat exchanger 10. The turbine 3 outlet is connected to the soot blowing pipe 5 through the first channel of the gas-vapor heat exchanger 10 and the third temperature sensor 11. The hot primary air pipe 2 is connected to the coal powder drying port of the coal mill 12 of the coal pulverizing system through the second channel of the gas-vapor heat exchanger 10. The hot primary air temperature in the hot primary air pipe 2 of this invention is 300℃. The 300℃ hot primary air exchanges heat with the low-temperature steam from the turbine 3 to compensate for the low-temperature steam temperature. The hot primary air through the gas-vapor heat exchanger 10 can enter the coal mill of the coal pulverizing system to dry the coal powder. As can be seen from the above, the above configuration of this invention can realize the coupling of the soot blowing system and the coal pulverizing system to achieve energy recovery.

[0022] Preferably, the hot primary air duct 2 is provided with a first tee 13 and a first valve 14, and a second tee 15 is provided between the second channel of the gas-steam heat exchanger 10 and the air inlet of the coal powder drying port of the coal mill 12. The third end of the first tee 13 is connected to the third end of the second tee 15 through the second valve 16. The temperature compensation unit described in this utility model not only compensates for the temperature of the low-temperature steam in the soot blowing system, but also compensates for the temperature of the hot primary air after heat exchange in the coal pulverizing system. Through the aforementioned bypass duct with the second valve 16, the unheated hot primary air can be directly mixed with the heat-exchanged hot primary air, thereby achieving temperature compensation for the heat-exchanged hot primary air and ensuring the drying effect of the coal powder in the coal mill 12. The above-mentioned configuration can achieve the stable operation of the coal pulverizing system without changing the original process design of the coal pulverizing system.

[0023] Preferably, a fourth temperature sensor 21 is provided between the second channel and the second three-way valve 15 of the gas-steam heat exchanger 10, and a fifth temperature sensor 22 is provided between the second three-way valve 15 and the coal powder drying port of the coal mill 12. The fourth temperature sensor 21 can detect the temperature of the hot primary air after heat exchange, and the fifth temperature sensor 22 can detect the temperature of the mixture of the unexchanged hot primary air and the hot primary air after heat exchange. The above detection can provide data support for adjusting the opening of the second valve 16.

[0024] Preferably, a flow meter 17, a second temperature sensor 18, and a second pressure sensor 19 are sequentially installed between the steam outlet of the low-temperature superheater 1 and the turbine 3. This arrangement allows for the detection of the temperature, flow rate, and pressure of the steam from the low-temperature superheater 1, ensuring the stable operation of the turbine 3.

[0025] like Figure 1 , 2As shown, this utility model also includes a PLC control system 20. The signal input terminals of the PLC control system 20 are respectively connected to the first pressure sensor 8, the third temperature sensor 11 and the fifth temperature sensor 22, and the signal output terminals of the PLC control system 20 are connected to the nozzle valve 7, the first valve 14 and the second valve 16. This utility model can be controlled manually or automatically. Regardless of the control method used, the purpose is to achieve safe and stable operation of the soot blowing system and the coal pulverizing system. Taking automatic control as an example, the first pressure sensor 8 provides the PLC control system 20 with data on the steam pressure after passing through the turbine 3. When the pressure is too high, the PLC control system 20 controls the nozzle valve 7 to increase the opening of the nozzle 6. When the pressure is too low, the PLC control system 20 controls the nozzle valve 7 to decrease the opening of the nozzle 6. The third temperature sensor 11 is used to detect the temperature of the steam after passing through the gas-steam heat exchanger 10. When the temperature is too low, the PLC control system 20 controls the first valve 14 to increase the opening. When the temperature is too high, the PLC control system 20 controls the first valve 14 to decrease the opening. The fifth temperature sensor 22 is used to detect the temperature of the hot primary air after passing through the gas-steam heat exchanger 10. When the temperature is too low, the PLC control system 20 controls the second valve 16 to increase the opening. When the temperature is too high, the PLC control system 20 controls the second valve 16 to decrease the opening.

[0026] The working principle of this utility model is as follows: Step 1: Obtain the real-time operating data of the target boiler, and determine the soot blowing sequence and cycle of the target boiler based on the real-time soot blowing requirements of the target boiler; Step 2: The flow meter 17, the second temperature sensor 18, and the second pressure sensor 19 at the steam outlet of the low-temperature superheater 1 monitor the steam flow, temperature, and pressure in real time, and can upload and monitor the above data and images; Step 3: The high-temperature and high-pressure steam at the steam outlet of the low-temperature superheater 1, with a pressure of 9.8 MPa and a temperature of 380℃, enters the turbine 3 through the nozzle 6 to drive the rotor of the turbine to rotate, and generates electricity from the generator 4. The steam pressure after passing through the turbine 3 drops to 1.1 MPa; Steam soot blowing pressure is an important parameter of the soot blowing system and must meet a certain range. If the pressure of the soot blower is too high, it may increase the risk of wear and damage to the soot blower and may shorten the service life of the soot blower and the boiler; if the pressure of the soot blower is too low, it may lead to poor cleaning effect of the soot blower, directly affecting the heat transfer efficiency and normal operation of the boiler. When the steam pressure after turbine 3 is below 1.1 MPa during operation, the opening of nozzle 6 is adjusted by nozzle valve 7 to decrease the opening of nozzle 6, thereby reducing the steam flow area and decreasing the working capacity of turbine 3, which in turn increases the outlet steam pressure. When the steam pressure after turbine 3 is above 1.1 MPa, the opening of nozzle 6 is adjusted by nozzle valve 7 to increase the opening of nozzle 6, which reduces the outlet steam pressure. High-temperature and high-pressure steam at 9.8 MPa and 380℃ drives the rotor of turbine 3. After the outlet pressure drops to 1.1 MPa, the steam temperature is approximately 200–220℃.

[0027] The initial state (9.8 MPa, 380 °C) was calculated based on the ideal isentropic expansion theory: By consulting tables or calculating, we assume that the initial enthalpy h1≈3150kJ / kg; Final pressure (1.1 MPa): Assume isentropic expansion to 1.1 MPa, with the final state being wet steam (partially liquefied). The corresponding theoretical enthalpy is h2≈2700 kJ / kg, and the temperature is T2≈180℃ (refer to the saturated steam table). The expansion process of a real turbine involves losses such as friction and heat leakage, necessitating the introduction of isentropic efficiency (η). The isentropic efficiency of industrial turbines is typically 0.7–0.85. Assuming an efficiency of η = 0.8, the actual enthalpy drop is: Δhactual = η * (h1)2 h2)=0.8×(3150 2700) = 360 kJ / kg; Actual final enthalpy: h2 = h1 Δh actual = 3150 360 = 2790 kJ / kg; Based on the saturated steam temperature (approximately 185℃) corresponding to 1.1MPa and the actual final enthalpy h2, combined with the pressure-enthalpy diagram, the actual final temperature can be found to be approximately 200–220℃.

[0028] The turbine output shaft is directly connected to generator 4 (generator 4 is a permanent magnet synchronous generator), which converts mechanical energy into electrical energy. The power generation is calculated as follows: Turbine efficiency: 80%; Generator efficiency: 95%; Actual output power: P = flow rate × Δh × turbine efficiency × generator efficiency = 5t / h×1000 kg / t×360kJ / kg×0.8×0.95÷3600s / h=380kW; Annual operating time: T=1200h; Annual power generation: E = 380kW × 1200h = 456000kWh.

[0029] Step 4: The low-temperature steam, with a pressure of 1.1 MPa and a temperature of 200-220℃ after passing through turbine 3, enters the first channel of the gas-steam heat exchanger 10; hot primary air from the boiler (temperature of 300℃) is drawn into the second channel of the gas-steam heat exchanger 10; the two exchange heat, reducing the low-temperature steam to 250-300℃ to meet the requirements of the soot blowing system; after heat exchange, the temperature can be detected by the third temperature sensor 11; if the temperature is insufficient, the opening of the first valve 14 can be increased to adjust the temperature; the temperature of the hot primary air after heat exchange is reduced to 180-200℃. Step 5: The operating parameters of the soot blowing steam pressure and temperature control process are acquired in real time and analyzed to provide immediate feedback and adjustment. Simultaneously, the turbine power generation is recorded. The steam pressure can be detected by the first pressure sensor 8, and the steam pressure is adjusted by adjusting the opening of the nozzle valve 7; the steam temperature can be detected by the third temperature sensor 11, and the temperature is adjusted by adjusting the opening of the first valve 14. Step 6: To ensure the drying effect of the hot primary air on the pulverized coal in the coal mill 12, the hot primary air can be divided into two streams. One stream undergoes heat exchange through the second channel of the gas-steam heat exchanger 10 and then enters the second three-way valve 15. The other stream enters the second three-way valve 15 directly without heat exchange through the second valve 16. After the two streams of hot primary air are combined and the temperature is maintained at around 260℃, they enter the coal mill 12. The temperature of the hot primary air is monitored by the fifth temperature sensor 22, and the temperature is adjusted by the opening of the second valve 16. This utility model, through the cooperation of the turbine 3 and the temperature compensation unit, maintains the superheat of the soot blowing steam ≥80℃ while recovering the mechanical energy of the residual steam pressure, avoiding the impact of condensate on the boiler heating surface, and achieving the purpose of environmental protection, energy saving, and safe operation. It realizes the unity of efficient recovery of residual pressure energy and safe operation of the boiler. Furthermore, the temperature compensation unit can not only compensate for the temperature of the steam, but also compensate for the temperature of the hot primary air, so that both the soot blowing system and the coal pulverizing system can operate stably for a long time.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A steam soot blowing residual pressure energy utilization anti-condensation device, comprising a low-temperature superheater (1) and a hot primary air duct (2), characterized in that: The steam outlet of the low-temperature superheater (1) is connected to the turbine (3), and the outlet of the turbine (3) is connected to the soot blowing pipe (5) through the temperature and pressure detection unit and the temperature compensation unit. The mechanical end of the turbine (3) is connected to the generator (4); The nozzle valve (7) is connected to the nozzle (6) inside the turbine (3); The hot primary air duct (2) is connected to the temperature compensation unit.

2. The anti-condensation device for utilizing residual pressure energy in steam soot blowing according to claim 1, characterized in that: The temperature and pressure detection unit includes a first pressure sensor (8) and a first temperature sensor (9) installed on the pipe at the outlet of the turbine (3).

3. The anti-condensation device for utilizing residual pressure energy from steam soot blowing according to claim 1, characterized in that: The temperature compensation unit includes a gas-vapor heat exchanger (10), and the turbine (3) outlet is connected to the soot blowing pipe (5) through the first channel and the third temperature sensor (11) of the gas-vapor heat exchanger (10). The hot primary air duct (2) is connected to the air inlet of the coal mill (12) of the coal pulverizing system through the second channel of the gas-steam heat exchanger (10).

4. The anti-condensation device for utilizing residual pressure energy from steam soot blowing according to claim 3, characterized in that: The hot primary air duct (2) is provided with a first tee (13) and a first valve (14). A second tee (15) is provided between the second channel of the gas-steam heat exchanger (10) and the coal powder drying port of the coal mill (12) of the coal pulverizing system. The third end of the first tee (13) is connected to the third end of the second tee (15) through the second valve (16).

5. The anti-condensation device for utilizing residual pressure energy from steam soot blowing according to claim 4, characterized in that: A fourth temperature sensor (21) is provided between the second channel and the second tee (15) of the gas heat exchanger (10), and a fifth temperature sensor (22) is provided between the second tee (15) and the coal powder drying port of the coal mill (12).

6. The anti-condensation device for utilizing residual pressure energy in steam soot blowing according to claim 1, characterized in that: A flow meter (17), a second temperature sensor (18), and a second pressure sensor (19) are sequentially installed between the steam outlet of the low-temperature superheater (1) and the turbine (3).

7. The anti-condensation device for utilizing residual pressure energy from steam soot blowing according to claim 1, characterized in that: It also includes a PLC control system (20), whose signal input terminals are connected to the first pressure sensor (8), the third temperature sensor (11) and the fifth temperature sensor (22), respectively, and whose signal output terminals are connected to the nozzle valve (7), the first valve (14) and the second valve (16).

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