High-parameter industrial steam supply system suitable for large coal-fired unit

Abstract

The invention provides a high-parameter industrial steam supply system suitable for a large coal-fired unit, belongs to the technical field of efficient combined heat and power generation of thermal generator sets, and solves the technical problem of realizing steam supply stability of the large coal-fired unit. A high-parameter industrial steam supply system suitable for a large coal-fired unit comprises a superheater, a steam-water separator, a high-pressure cylinder, a low-pressure cylinder, a reheater, a steam heat accumulator, a condenser and a booster pump, an outlet of the superheater is connected with the steam-water separator, and the steam-water separator is connected with a temperature and pressure reducer and the high-pressure cylinder; the desuperheater desuperheats and decompresses the main steam and then supplies external high-pressure steam; an outlet of the high-pressure cylinder is sequentially connected with the reheater, the medium-pressure cylinder and the low-pressure cylinder. According to the invention, thermodynamic cycle of a large coal-fired unit can be better matched, the steam throttling loss is reduced, the overall heat efficiency of the unit is improved, the power generation coal consumption is reduced, the gradient utilization of energy is realized, and the value of coal resources is more fully excavated.

Description

Technical Field

[0001] The invention belongs to the technical field of high-efficiency cogeneration of thermal power generating sets, relates to steam supply for large coal-fired units, and in particular to a high-parameter industrial steam supply system suitable for large coal-fired units. Background Art

[0002] With the rapid development of industry, the demand for high-parameter steam is growing, especially in the chemical, pharmaceutical, papermaking and other industries. A stable and reliable high-parameter industrial steam supply system is crucial. Large coal-fired units, as an important energy conversion device, have the potential to provide large-scale steam, but the traditional coal-fired unit steam supply system has gradually exposed many shortcomings when facing the high-parameter industrial steam supply demand. In order to meet the strict requirements of modern industry for high-parameter steam, while taking into account energy efficient utilization and environmental protection, it is urgently necessary to conduct in-depth research and technological innovation on the steam supply system suitable for large coal-fired units, and develop a new high-parameter industrial steam supply system to fill the gap in existing technologies and promote the sustainable development of industrial production.

[0003] After searching, the Chinese patent authorization number CN110671161A discloses a high-parameter industrial steam supply system and method suitable for large coal-fired units, including a superheater, a temperature and pressure reducer, a high-pressure cylinder, a low-pressure cylinder, a high-pressure heater, a booster pump and a flash device: the outlet of the superheater is respectively connected to the inlet of the high-pressure cylinder and the temperature and pressure reducer; the temperature and pressure reducer cools and reduces the main steam and then supplies high-pressure gas to the outside; the outlet of the high-pressure cylinder is connected to the reheater, the medium-pressure cylinder and the low-pressure cylinder in sequence; the condensate return water or make-up water is respectively connected to the temperature and pressure reducer, the flash device and the inlet of the reheater through the booster pump. The present invention does not require irreversible modification of the heating surface of the boiler reheater, and there is no obvious modification risk; finally, the system of the present invention is simple, reliable in operation, and can flexibly adapt to the situation of fluctuation, reduction or even suspension of steam supply, ensuring that the outlet steam temperature of the boiler reheater is maintained in a relatively stable range, and ensuring that the safety of the unit operation is not affected by the fluctuation of steam supply.

[0004] The above-mentioned patent discloses a high-parameter industrial steam supply system and method suitable for large coal-fired units, which has the following shortcomings: when the combustion unit supplies high-pressure steam to the outside, the excess steam discharged from the exhaust port of the low-pressure cylinder is not effectively utilized, and the excess steam is condensed into condensate by the condenser, which reduces the thermal efficiency of the reheater. At the same time, the supply of condensate or make-up water through the booster pump and the supply to the reheater through vaporization by the flash evaporation device increase energy consumption and water waste. Therefore, a high-parameter industrial steam supply system suitable for large coal-fired units is designed. Summary of the invention

[0005] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a high-parameter industrial steam supply system suitable for large coal-fired units. The technical problem to be solved by the invention is: how to achieve the steam supply stability of large coal-fired units and improve energy utilization.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A high-parameter industrial steam supply system suitable for large coal-fired units, including a superheater, a steam-water separator, a high-pressure cylinder, a low-pressure cylinder, a reheater, a steam accumulator, a condenser and a booster pump. The outlet of the superheater is connected to the steam-water separator, and the steam-water separator is connected to the temperature and pressure reducing device and the high-pressure cylinder respectively; The desuperheater and pressure reducer reduces the temperature and pressure of the main steam and then supplies high-pressure steam to the outside. The outlet of the high-pressure cylinder is connected to the reheater, the medium-pressure cylinder and the low-pressure cylinder in sequence; The low-pressure cylinder is connected to the steam accumulator and condenser respectively; The outlet of the steam accumulator is mixed with the exhaust gas of the high-pressure cylinder and connected to the inlet of the reheater; The condenser outlet is connected with a booster pump and a condensate pump respectively; The booster pump is connected to the desuperheater and pressure reducer and the reheater respectively; The outlet of the condensate pump is connected to the low-pressure heater, deaerator, feed water pump and high-pressure heater in sequence; The outlet of the high pressure heater is connected to the inlet of the superheater.

[0007] The working principle of the present invention is: when high-pressure steam is not supplied to the outside, all the second regulating valve, the second stop valve, the first stop valve, the first regulating valve, the fourth regulating valve, the fourth stop valve, the seventh stop valve, the seventh regulating valve, the fifth stop valve, and the fifth regulating valve are closed, and the outlet steam of the superheater enters the high-pressure cylinder through the steam-water separator to do work, and the exhaust steam enters the reheater for a second heating, and the outlet reheated steam enters the medium-pressure cylinder and the low-pressure cylinder, so that the medium-pressure cylinder and the low-pressure cylinder perform work in turn, and the exhaust steam in the low-pressure cylinder enters the condenser to condense, and the condensate passes through the condensate pump, and then passes through the low-pressure heater deaerator, the feed water pump, and the high-pressure heater in turn, and finally passes through the high-pressure heater to the superheater to become high-temperature steam and enter the high-pressure cylinder to continue to do work. When high-pressure steam is needed to be supplied to the outside When steam is discharged, all regulating valves and stop valves are opened. After the steam in the superheater passes through the steam-water separator, part of it enters the temperature and pressure reducing device through the fourth regulating valve and the fourth stop valve. At the same time, the condensate obtained by the booster pump from the condenser passes through the first regulating valve and the first stop valve to the temperature and pressure reducing device, so as to reduce the temperature and pressure of the steam in the temperature and pressure reducing device and realize external high-pressure steam supply. At the same time, most of the excess steam in the low-pressure cylinder is stored in the steam accumulator, and is mixed with the exhaust steam in the high-pressure cylinder through the second regulating valve and the second stop valve to enter the boiler reheater to make up for the reduced amount of high-pressure cylinder steam entering the reheater. At the same time, the booster pump sprays part of the condensate into the reheater through the third regulating valve and the third stop valve to mix and cool the reheated steam to prevent the reheater from overheating.

[0008] A fourth regulating valve and a fourth stop valve are arranged on the connecting pipeline between the steam-water separator and the temperature and pressure reducing device.

[0009] With the above structure, the amount of high-temperature steam obtained by the temperature-reducing and pressure-reducing device can be controlled by setting the fourth regulating valve and the fourth stop valve.

[0010] A first regulating valve and a first stop valve are arranged on the connecting pipeline between the boosting pump and the temperature and pressure reducing device, and a third stop valve and a third regulating valve are arranged on the connecting pipeline between the boosting pump and the reheater.

[0011] With the above structure, the booster pump can regulate the condensate obtained by setting the first regulating valve, the first stop valve, the third stop valve and the third regulating valve, so as to ensure that the desuperheater and the reheater can work stably. The connecting pipeline between the steam accumulator and the reheater is provided with a second regulating valve and a second stop valve, and the connecting pipeline between the steam accumulator and the low-pressure cylinder is provided with a fifth regulating valve and a fifth stop valve; The connecting pipeline between the condenser and the low-pressure cylinder is provided with a sixth regulating valve and a sixth stop valve, the connecting pipeline between the booster pump and the condenser is provided with a seventh stop valve and a seventh regulating valve, and the connecting pipeline between the condensate pump and the condenser is provided with an eighth regulating valve and an eighth stop valve.

[0012] With the above structure, the steam accumulator can regulate the amount of excess steam obtained from the low-pressure cylinder and the amount delivered to the reheater. At the same time, the condensate of the condenser can be adjusted and distributed to the booster pump and condensate pump in real time according to demand.

[0013] Compared with the prior art, the high-parameter industrial steam supply system suitable for large coal-fired units of the present invention has the following advantages: 1. In the present invention, it can better match the thermal cycle of large coal-fired units, reduce steam throttling losses, improve the overall thermal efficiency of the units, reduce coal consumption for power generation, realize the cascade utilization of energy, and allow coal resources to be more fully exploited. Compared with traditional steam supply methods, the high-parameter system can greatly increase the industrial steam supply without affecting the power generation capacity, meet the large-scale steam demand of industrial parks, etc., and the steam supply of a single unit can reach more than 200t / h, which effectively guarantees industrial production.

[0014] 2. In the present invention, the high-parameter steam supply system can better match the thermal cycle of large coal-fired units, reduce steam throttling losses, improve the overall thermal efficiency of the units, reduce coal consumption for power generation, realize the cascade utilization of energy, and allow coal resources to be more fully exploited.

[0015] 3. In the present invention, the good adaptation of large coal-fired units and high-parameter steam supply systems can ensure the continuous and stable supply of industrial steam, reduce the risk of production interruption, and ensure the continuity of industrial production processes, which is especially important for continuous production enterprises and reduces the economic losses of enterprises caused by unstable steam supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a high-parameter industrial steam supply system suitable for large coal-fired units of the present invention.

[0017] In the figure, 1, high-pressure cylinder; 2, medium-pressure cylinder; 3, low-pressure cylinder; 4, superheater; 5, temperature and pressure reducer; 6, reheater; 7, first regulating valve; 8, first stop valve; 9, second regulating valve; 10, second stop valve; 11, third regulating valve; 12, third stop valve; 13, booster pump; 14, high-pressure heater; 15, deaerator; 16, feed water pump; 17, low-pressure heater; 18, condensate pump; 19, condenser; 20, fourth regulating valve; 21, fourth stop valve; 22, fifth regulating valve; 23, fifth stop valve; 24, sixth regulating valve; 25, sixth stop valve; 26, seventh regulating valve; 27, seventh stop valve; 28, eighth regulating valve; 29, eighth stop valve; 30, steam-water separator; 31, steam accumulator. DETAILED DESCRIPTION

[0018] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0019] like Figure 1 , as shown, a high-parameter industrial steam supply system suitable for large coal-fired units, including a superheater 4, a steam-water separator 30, a high-pressure cylinder 1, a low-pressure cylinder 3, a reheater 6, a steam accumulator 31, a condenser 19 and a booster pump 13, the outlet of the superheater 4 is connected to the steam-water separator 30, and the steam-water separator 30 is respectively connected to the temperature-reducing and pressure-reducing device 5 and the high-pressure cylinder 1; The desuperheater and pressure reducer 5 desuperheats and reduces the pressure of the main steam and then supplies high-pressure steam to the outside; The outlet of the high-pressure cylinder 1 is connected to the reheater 6, the medium-pressure cylinder 2 and the low-pressure cylinder 3 in sequence; The low pressure cylinder 3 is connected to the steam accumulator 31 and the condenser 19 respectively; The outlet of the steam accumulator 31 is mixed with the exhaust gas of the high pressure cylinder 1 and connected to the inlet of the reheater 6; The outlet of the condenser 19 is connected to a booster pump 13 and a condensate pump 18 respectively; The boost pump 13 is connected to the desuperheater 5 and the reheater 6 respectively; The outlet of the condensate pump 18 is connected to the low-pressure heater 17, the deaerator 15, the feed water pump 16, and the high-pressure heater 14 in sequence; The outlet of the high pressure heater 14 is connected to the inlet of the superheater 4 .

[0020] In this embodiment, a fourth regulating valve 20 and a fourth stop valve 21 are provided on the connecting pipeline between the steam-water separator 30 and the temperature-reducing and pressure-reducing device 5. The fourth regulating valve 20 and the fourth stop valve 21 are provided to adjust the amount of steam supplied to the temperature-reducing and pressure-reducing device 5.

[0021] In this embodiment, a first regulating valve 7 and a first stop valve 8 are provided on the connecting pipeline between the boosting pump 13 and the desuperheater 5, and a third stop valve 12 and a third regulating valve 11 are provided on the connecting pipeline between the boosting pump 13 and the reheater 6. Through the cooperation of the first regulating valve 7, the first stop valve 8, the second regulating valve 9 and the second stop valve 10, the condensate obtained by the boosting pump 13 can be adjusted according to the actual situation to be delivered to the desuperheater 5 and the reheater 6, so as to ensure that the desuperheater 5 and the reheater 6 can work stably.

[0022] In this embodiment, the connecting pipeline between the steam accumulator 31 and the reheater 6 is provided with a second regulating valve 9 and a second stop valve 10, and the connecting pipeline between the steam accumulator 31 and the low-pressure cylinder 3 is provided with a fifth regulating valve 22 and a fifth stop valve 23. Through the setting of the fifth regulating valve 22 and the fifth stop valve 23, it is convenient to adjust the steam storage speed and amount of the steam accumulator 31 in real time according to the actual situation of the steam accumulator 31.

[0023] In this embodiment, the connecting pipeline between the condenser 19 and the low-pressure cylinder 3 is provided with a sixth regulating valve 24 and a sixth stop valve 25. The setting of the sixth regulating valve 24 and the sixth stop valve 25 controls the amount of excess steam entering the condenser 19 to ensure that the steam accumulator 31 has sufficient amount for storage.

[0024] In this embodiment, the connecting pipeline between the boost pump 13 and the condenser 19 is provided with a seventh stop valve 27 and a seventh regulating valve 26. Through the setting of the seventh stop valve 27 and the seventh regulating valve 26, the condensate in the condenser 19 can be adjusted according to demand to enter the boost pump 13.

[0025] In this embodiment, the connecting pipeline between the condensate pump 18 and the condenser 19 is provided with an eighth regulating valve 28 and an eighth stop valve 29. The setting of the eighth regulating valve 28 and the eighth stop valve 29 makes it easy to adjust the amount of condensate supplied to the superheater 4.

[0026] The working principle of the present invention is as follows: when high-pressure steam is not supplied to the outside, all the second regulating valves 9, the second stop valve 10, the first stop valve 8, the first regulating valve 7, the fourth regulating valve 20, the fourth stop valve 21, the seventh stop valve 27, the seventh regulating valve 26, the fifth stop valve 23, and the fifth regulating valve 22 are closed, and the outlet steam of the superheater 4 enters the high-pressure cylinder 1 through the steam-water separator 30 to perform work, and the exhaust steam enters the reheater 6 for a second heating, and the outlet reheated steam enters the medium-pressure cylinder 2 and the low-pressure cylinder 3, so that the medium-pressure cylinder 2 and the low-pressure cylinder 3 perform work in turn, and the exhaust steam in the low-pressure cylinder 3 enters the condenser 19 to condense, and the condensate passes through the condensate pump 18, and then passes through the low-pressure heater 17, the deaerator 15, the feed water pump 16, and the high-pressure heater 14 in turn, and finally passes through the high-pressure heater 14 to the superheater 4 to become high-temperature steam and enter the high-pressure cylinder 1 to continue to perform work. When it is necessary to When high-pressure steam is supplied from outside, all regulating valves and stop valves are opened. After the steam in the superheater 4 passes through the steam-water separator 30, part of it enters the temperature-reducing and pressure-reducing device 5 through the fourth regulating valve 20 and the fourth stop valve 21. At the same time, the condensate obtained by the booster pump 13 from the condenser 19 passes through the first regulating valve 7 and the first stop valve 8 to the temperature-reducing and pressure-reducing device 5, so that the temperature and pressure of the steam in the temperature-reducing and pressure-reducing device 5 are reduced, and high-pressure steam supply to the outside is realized. At the same time, most of the excess steam in the low-pressure cylinder 3 is stored in the steam accumulator 31, and is mixed with the exhaust steam in the high-pressure cylinder 1 through the second regulating valve 9 and the second stop valve 10 to enter the boiler reheater 6, so as to make up for the reduced amount of steam from the high-pressure cylinder 1 entering the reheater 6. At the same time, the booster pump 13 sprays part of the condensate into the reheater 6 through the third regulating valve 11 and the third stop valve 12, mixes and cools the reheated steam, and prevents the reheater 6 from overheating.

[0027] In summary, in the present invention, by setting the steam accumulator 31, the excess steam in the low-pressure cylinder 3 can be stored and transferred, which is convenient for direct supply to the reheater 6. After being stored, it is used for direct supply to the reheater 6, so that the steam can be reused in the system, avoiding unnecessary loss of energy and improving the energy utilization rate of the entire coal-fired unit. When the steam demand of the reheater 6 fluctuates, the steam accumulator 31 can play a buffering role. It can replenish the steam required by the reheater 6 in time, ensure the relative stability of the steam parameters imported from the reheater 6, and help the reheater 6 to work stably, thereby ensuring the stability of the output steam parameters of the entire steam supply system, meeting the steam demand of industrial production, etc., and helping to optimize the large-scale coal-fired unit. The operating conditions of each component of the unit can be improved, the service life of the equipment can be extended, and the maintenance cost can be reduced. At the same time, the steam-water separator 30 can improve the steam quality, remove water droplets in the steam, meet the demand for high-quality steam in high-precision industrial production, improve the system operation efficiency, reduce the energy loss and pipeline resistance caused by water, and make steam transmission smoother; it can also stabilize the steam parameters, avoid the fluctuations of steam temperature and pressure caused by changes in water content, provide a stable and reliable steam supply for industrial production, and ensure the stable and efficient operation of the entire steam supply system. At the same time, the condenser 19 is used to supply condensate to the booster pump 13 and the condensate pump 18, so that the condensate can be fully utilized, improve the utilization rate of the condensate, and avoid additional water supply.

[0028] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A high-parameter industrial steam supply system suitable for a large coal-fired unit, comprising a superheater (4), a steam-water separator (30), a high-pressure cylinder (1), a low-pressure cylinder (3), a reheater (6), a steam accumulator (31), a condenser (19) and a booster pump (13), characterized in that: The outlet of the superheater (4) is connected to the steam-water separator (30), and the steam-water separator (30) is respectively connected to the temperature-reducing and pressure-reducing device (5) and the high-pressure cylinder (1); The temperature and pressure reducing device (5) reduces the temperature and pressure of the main steam and then supplies high-pressure steam to the outside; The outlet of the high-pressure cylinder (1) is connected to the reheater (6), the medium-pressure cylinder (2) and the low-pressure cylinder (3) in sequence; The low-pressure cylinder (3) is connected to the steam accumulator (31) and the condenser (19) respectively; The outlet of the steam accumulator (31) is mixed with the exhaust gas of the high-pressure cylinder (1) and then connected to the inlet of the reheater (6); The outlet of the condenser (19) is respectively connected to a booster pump (13) and a condensate pump (18); The booster pump (13) is connected to the temperature reducing and pressure reducing device (5) and the reheater (6) respectively; The outlet of the condensate pump (18) is connected in sequence to the low-pressure heater (17), the deaerator (15), the feed water pump (16), and the high-pressure heater (14); The outlet of the high pressure heater (14) is connected to the inlet of the superheater (4).

2. A high-parameter industrial steam supply system suitable for large coal-fired units according to claim 1, characterized in that: A fourth regulating valve (20) and a fourth stop valve (21) are provided on the connecting pipeline between the steam-water separator (30) and the temperature and pressure reducing device (5).

3. A high-parameter industrial steam supply system suitable for large coal-fired units according to claim 1, characterized in that: A first regulating valve (7) and a first stop valve (8) are provided on the connecting pipeline between the boosting pump (13) and the temperature reducing and pressure reducing device (5), and a third stop valve (12) and a third regulating valve (11) are provided on the connecting pipeline between the boosting pump (13) and the reheater (6).

4. A high-parameter industrial steam supply system suitable for large coal-fired units according to claim 1, characterized in that: The connecting pipeline between the steam accumulator (31) and the reheater (6) is provided with a second regulating valve (9) and a second stop valve (10), and the connecting pipeline between the steam accumulator (31) and the low-pressure cylinder (3) is provided with a fifth regulating valve (22) and a fifth stop valve (23).

5. A high-parameter industrial steam supply system suitable for large coal-fired units according to claim 1, characterized in that: The connecting pipeline between the condenser (19) and the low-pressure cylinder (3) is provided with a sixth regulating valve (24) and a sixth stop valve (25).

6. A high-parameter industrial steam supply system suitable for large coal-fired units according to claim 1, characterized in that: The connecting pipeline between the booster pump (13) and the condenser (19) is provided with a seventh stop valve (27) and a seventh regulating valve (26).

7. A high-parameter industrial steam supply system suitable for large coal-fired units according to claim 1, characterized in that: The connecting pipeline between the condensate pump (18) and the condenser (19) is provided with an eighth regulating valve (28) and an eighth stop valve (29).

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