An energy system for producing compressed air from high-flow-rate main steam extraction in thermal power units.

Abstract

This invention discloses an energy system for producing compressed air from high-flow-rate main steam extraction in a thermal power unit. The system includes a thermal power unit comprising a boiler assembly, a high-pressure cylinder, and an intermediate-pressure cylinder. A main steam pipeline connects the boiler assembly and the high-pressure cylinder. A main diversion pipeline connects to the main steam pipeline, which in turn connects to a small steam turbine. The small steam turbine is driven by a compressed gas assembly. A cold reheat steam pipeline connects the high-pressure cylinder and the boiler assembly. An exhaust steam pipeline connects to the small steam turbine. A drive steam pipeline extends from the main steam pipeline. The exhaust steam pipeline and the drive steam pipeline merge and connect to the cold reheat steam pipeline via a return pipeline. This invention, by establishing the exhaust steam pipeline and the drive steam pipeline, increases the steam extraction flow rate to the main steam pipeline, exceeding the original 10% extraction flow rate limit for the unit. It also achieves a stable, efficient, and reliable supply of compressed gas to the coal-fired power unit, increasing the product range available for sale from coal-fired power units.

Description

Technical Field

[0001] This invention relates to the field of energy utilization technology, and in particular to an energy system for producing compressed air by extracting large-flow main steam from a thermal power unit. Background Technology

[0002] Currently, most combined heat and power (CHP) units in China use direct heat supply to achieve CHP, such as directly supplying steam and hot water. Urban coal-fired power plants have abundant and diverse steam resources, which can not only provide heat and electricity, but also have the ability to provide compressed air, compressed carbon dioxide, and other products.

[0003] Currently, most chemical plants use gas turbines or electric compressors to produce compressed gas. These methods consume a lot of energy and are not economical.

[0004] Furthermore, the steam available for driving the small steam turbine in a coal-fired unit can be selected from main steam, cold reheat steam, and hot reheat steam. Among these, the pressure of cold reheat steam and hot reheat steam is reduced, resulting in a higher enthalpy value of the exhaust steam after driving the small steam turbine and lower energy efficiency. Main steam can be better recovered and reused after driving the small steam turbine, but the amount of main steam extracted is constrained by the overheating of the boiler reheater, and generally the amount of main steam extracted does not exceed 10% of the main steam flow.

[0005] In summary, the applicant believes that there is a lack of existing technologies that can produce compressed gas by extracting large-flow main steam from thermal power units, thus failing to achieve large-scale, high-efficiency, and low-cost production of compressed gas products from coal-fired power units. Summary of the Invention

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] To achieve the above objectives, this invention proposes an energy system for producing compressed air from high-flow-rate main steam extraction in a thermal power unit. The system includes a thermal power unit comprising a boiler assembly, a high-pressure cylinder, and an intermediate-pressure cylinder. A main steam pipeline is provided between the boiler assembly and the high-pressure cylinder. A main diversion pipeline is connected to the main steam pipeline. The main diversion pipeline is connected to a small steam turbine. A compressed gas assembly is driven by the small steam turbine. A cold reheat steam pipeline is provided between the high-pressure cylinder and the boiler assembly. An exhaust steam pipeline is connected to the small steam turbine. A drive steam pipeline is led out from the main steam pipeline. The exhaust steam pipeline and the drive steam pipeline are connected and merged, and then connected to the cold reheat steam pipeline via a return pipeline.

[0008] This invention increases the steam extraction flow rate of the main steam pipeline by setting up exhaust steam pipelines and drive steam pipelines, exceeding the original 10% steam extraction flow rate limit of the unit, and realizes a stable, efficient and reliable supply of compressed gas to coal-fired power units, thereby increasing the variety of coal-fired power unit products for sale.

[0009] Optionally, a first check valve, a first regulating valve, and a first isolation valve are sequentially installed on the main diversion pipe along the direction from the main steam pipe to the small steam turbine.

[0010] Furthermore, the compressed gas assembly includes a first compressor that is drivenly connected to the small steam turbine, the compressor is connected to a gas source pipeline, the gas source pipeline is connected to a compressed gas source, and the outlet of the first compressor is connected to a gas product pipeline.

[0011] Furthermore, a hot press for mixing the exhaust steam from the small steam turbine and the driving steam is provided at the connection position between the exhaust steam pipe and the driving steam pipe. The hot press is connected to both the driving steam pipe and the exhaust steam pipe. The outlet of the hot press is connected to the cold reheat steam pipe through a return pipe.

[0012] Furthermore, a second check valve, a second regulating valve, and a second isolation valve are sequentially installed on the drive steam pipe along the direction from the main steam pipe to the hot press.

[0013] Furthermore, a third regulating valve is installed on the return pipe at the position corresponding to the hot press and the cold reheat steam pipe.

[0014] Furthermore, the intermediate pressure cylinder is connected to a deaerator, the deaerator outlet is equipped with a water pump, the water pump outlet is equipped with a water inlet pipe, and the water inlet pipe is connected to the hot press.

[0015] Furthermore, the gas source pipeline is connected to a second compressor, which is an electric compressor.

[0016] Furthermore, the small steam turbine is connected to the first compressor via a steam drive shaft.

[0017] Furthermore, the exhaust pressure in the exhaust pipe is 1-2 MPa.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is a schematic diagram of the structure of an energy system for producing compressed air by extracting large-flow main steam from a thermal power unit according to the present invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Boiler assembly; 2. High-pressure cylinder; 3. Intermediate-pressure cylinder; 4. Main steam pipeline; 5. Main diversion pipeline; 6. Exhaust pipeline; 7. Drive steam pipeline; 8. Return pipeline; 9. Cold / reheat steam pipeline; 10. First compressor; 11. Second compressor; 12. Gas source pipeline; 13. Water intake pipeline; 14. Hot press; 15. Small steam turbine; 16. First check valve; 17. First regulating valve; 18. First isolation valve; 19. Second check valve; 20. Second regulating valve; 21. Second isolation valve; 22. Third regulating valve. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] This invention provides an energy system for producing compressed air by extracting large-flow main steam from a thermal power unit, as described below. Figure 1 To elaborate in detail.

[0025] An energy system for producing compressed air by extracting large-flow main steam from a thermal power unit includes a thermal power unit. The thermal power unit includes a boiler assembly 1, a high-pressure cylinder 2, and an intermediate-pressure cylinder 3. A main steam pipe 4 is provided between the boiler assembly 1 and the high-pressure cylinder 2. A main diversion pipe 5 is connected to the main steam pipe 4. The main diversion pipe 5 is connected to a small steam turbine 15. A compressed gas assembly is driven by the small steam turbine 15. A cold reheat steam pipe 9 is provided between the high-pressure cylinder 2 and the boiler assembly 1. An exhaust steam pipe 6 is connected to the small steam turbine 15. A drive steam pipe 7 is led out from the main steam pipe 4. The exhaust steam pipe and the drive steam pipe 7 are connected and merged, and then connected to the cold reheat steam pipe 9 through a return pipe 8.

[0026] The thermal power unit includes a boiler assembly 1, a high-pressure cylinder 2, and an intermediate-pressure cylinder 3. The main steam pipe 4 of the boiler assembly 1 is connected to the inlet of the high-pressure cylinder 2. The boiler assembly 1 includes a boiler reheater and is also connected to a hot reheat steam pipe. The hot reheat steam pipe is connected to the inlet of the intermediate-pressure cylinder 3. The outlets of the high-pressure cylinder 2 and the intermediate-pressure cylinder 3 are connected to a regenerative system. The regenerative system includes a No. 1 high-temperature feedwater heater, a No. 2 high-temperature feedwater heater, a No. 3 high-temperature feedwater heater, and a deaerator feedwater assembly, which are connected in sequence by pipes. The No. 1 high-temperature feedwater heater is connected to the inlet of the boiler assembly 1, and the deaerator feedwater assembly is connected to the intermediate-pressure cylinder 3. The two steam outlets of the high-pressure cylinder 2 are respectively connected to the No. 1 high-temperature feedwater heater and the No. 2 high-temperature feedwater heater. The other steam outlet of the intermediate-pressure cylinder 3 is connected to the No. 3 high-temperature feedwater heater. The No. 1 high-temperature feedwater heater (referred to as the high-pressure heater in the figure, the same below), the No. 2 high-temperature feedwater heater, the No. 3 high-temperature feedwater heater, and the deaerator feedwater assembly are also connected in sequence by a return flow pipe.

[0027] A portion of steam is drawn from the main steam pipe 4 along the main diversion pipe 5 to power the small steam turbine 15. The small steam turbine 15 drives the compressed gas assembly to perform compressed gas operation. At the same time, a drive steam pipe 7 is installed on the main steam pipe 4, and a portion of steam is drawn from the main steam pipe 4 as drive steam to accelerate the exhaust of the small steam turbine 15, thereby promoting the steam extraction from the main steam pipe 4 by the small steam turbine 15.

[0028] This invention increases the steam extraction flow rate of the main steam pipeline 4 by drawing a drive steam pipeline 7 and setting an exhaust steam pipeline on the original main steam pipeline 4 of the thermal power unit, exceeding the original unit's 10% steam extraction flow rate limit. It also enables a stable, efficient, and reliable supply of compressed gas to the coal-fired power unit, thereby increasing the variety of coal-fired power unit products available for sale.

[0029] In some embodiments, a first check valve 16, a first regulating valve 17, and a first isolation valve 18 are sequentially arranged on the main diversion pipe 5 along the direction from the main steam pipe 4 to the small steam turbine 15. The arrangement of the first check valve 16 and the first isolation valve 18 can facilitate system isolation between the main steam pipe 4 and the small steam turbine, and the first regulating valve 17 can effectively control the amount of steam entering the small steam turbine 15.

[0030] In some embodiments, the compressed gas assembly includes a first compressor 10 drivenly connected to a small steam turbine 15. The compressor is connected to a gas source pipeline 12, which is connected to a compressed gas source. The outlet of the first compressor 10 is connected to a gas product pipeline. The compressed gas source can be various gases such as air, carbon dioxide, and nitrogen. The small steam turbine 15 drives the first compressor 10 to work under the drive of steam extracted from the main steam pipeline 4. The compressed gas source enters the first compressor 10 along the gas source pipeline 12, and the gas is output along the gas product pipeline after being compressed by the first compressor 10.

[0031] In some embodiments, the small steam turbine 15 and the first compressor 10 are connected by a steam drive shaft.

[0032] In some embodiments, the gas source pipeline 12 is connected to a second compressor 11, which is an electric compressor. When the thermal power unit or small steam turbine 15 needs maintenance or malfunctions, the second compressor 11 can maintain the gas compression operation normally, thereby ensuring the normal production supply of compressed gas.

[0033] In some embodiments, the exhaust pressure in the exhaust pipe 6 is 1-2 MPa.

[0034] In some embodiments, a hot press 14 for mixing the exhaust steam from the small steam turbine 15 and the driving steam is provided at the connection point between the exhaust steam pipe 6 and the driving steam pipe 7. The hot press 14 is connected to both the driving steam pipe 7 and the exhaust steam pipe 6, and its outlet is connected to the cold reheat steam pipe 9. The hot press 14 can mix and compress the steam in the two pipes and supply it back into the cold reheat steam pipe 9 for reheating of the boiler assembly 1, thereby increasing the gas flow rate entering the boiler assembly 1.

[0035] In some embodiments, a second check valve 19, a second regulating valve 20, and a second isolation valve 21 are sequentially arranged on the drive steam pipe 7 along the direction from the main steam pipe 4 to the hot press 14. The arrangement of the second check valve 19 and the second isolation valve 21 can facilitate system isolation between the main steam pipe 4 and the drive steam pipe 7, and the second regulating valve 20 can effectively control the amount of steam entering the drive steam pipe 7.

[0036] In some embodiments, in order to control the steam flow rate supplied by the hot press 14 to the cold reheat steam pipeline 9, a third regulating valve is provided on the return pipeline 8 at a position corresponding to the hot press 14 and the cold reheat steam pipeline 9, for controlling the steam flow rate in the pipeline between the hot press 14 and the cold reheat steam pipeline 9.

[0037] In some embodiments, to adjust the steam temperature within the hot press 14, desuperheating water needs to be supplied from the outside. Considering that the original thermal power unit's regenerative system includes a deaerator feedwater assembly for deaerating and cooling steam, this assembly includes a deaerator connected to the intermediate-pressure cylinder 3. A feedwater pump is installed at the deaerator outlet, and a water inlet pipe 13 is installed at the feedwater pump outlet. The water inlet pipe 13 is connected to the hot press 14, supplying a portion of the condensate from the regenerative system to the hot press 14 for cold / warm water supply. This reduces the need to reintroduce water from the external environment, thus reducing manpower and material costs. The exhaust steam from the small turbine is fed into the hot press 14 as the injected steam. The main steam and the small turbine exhaust steam are mixed and blended in the hot press 14, supplemented by a portion of desuperheating water, adjusting the exhaust steam pressure and temperature to match the cold reheat steam pressure. Then, the steam flows to the boiler reheater inlet in the boiler assembly 1.

[0038] This invention enables a stable, efficient, and reliable supply of compressed gas to coal-fired power units, increasing the variety of products available for sale and identifying new profit points. The compressed gas supply guarantee offers high flexibility, significantly improving the operational flexibility of the unit. It also achieves a substantial increase in main steam extraction capacity, exceeding the original 10% extraction flow limit for each unit. A comparison with no steam extraction, traditional steam extraction, and this solution is as follows:

[0039] 1) Under non-extraction conditions, when the main steam flow rate is 1Q, the main steam extraction rate is 0, the total extraction rate of No. 1 high-temperature feedwater heater and No. 2 high-temperature feedwater heater is 0.15Q, and the cold reheat steam is 0.85Q. This inlet flow rate is the safe operating flow rate of boiler component 1 (at this time, the cold reheat steam flow rate is the inlet flow rate of the boiler reheater).

[0040] 2) Traditional steam extraction scheme: When the main steam flow rate is 1Q, the maximum steam extraction rate of the main steam is 0.1Q, the total steam extraction rate of No. 1 high-temperature feedwater heater and No. 2 high-temperature feedwater heater is 0.15Q, and the cold reheat steam is 0.75Q under the condition that the boiler reheater does not overheat (0.75Q is the minimum flow rate for the reheater to not overheat, and at this time the cold reheat steam flow rate is the inlet flow rate of the boiler reheater).

[0041] 3) The present invention can achieve the following when the main steam flow rate is 1Q: 0.2Q steam is extracted to the small turbine, 0.2Q steam is extracted to the driving steam, the total steam extraction of No. 1 high-temperature feedwater heater and No. 2 high-temperature feedwater heater is 0.15Q, the cold reheat steam is 0.55Q, and the boiler reheater inlet flow rate is 0.85Q (the boiler reheater inlet flow rate is equal to the cold reheat steam flow rate plus the mixed steam flow rate).

[0042] In summary, this invention can achieve large-flow main steam extraction.

[0043] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An energy system for producing compressed air from main steam extraction of a large flow of a thermal power unit, characterized in that, The utility model provides a kind of steam turbine unit, including thermal power generating unit, the thermal power generating unit includes boiler assembly, high-pressure cylinder and medium-pressure cylinder, main steam pipe is provided between the boiler assembly with high-pressure cylinder, main flow guide pipe is communicated and arranged on the main steam pipe, small steam turbine is communicated with the main flow guide pipe, compressed gas assembly is drivingly connected with the small steam turbine, cold reheat steam pipe is provided between the high-pressure cylinder with the boiler assembly, exhaust pipe is communicated and arranged with the small steam turbine, drive steam pipe is communicated and arranged with the main steam pipe being led out, the exhaust pipe and the drive steam pipe are communicated and merged after confluence, and are communicated with the cold reheat steam pipe by backflow pipe; The exhaust pipe and the drive steam pipe are provided with a hot press for mixing small steam turbine exhaust steam and drive steam at the connection position, the hot press is communicated and arranged with the drive steam pipe and the exhaust pipe, and the hot press outlet is communicated and arranged with the cold reheat steam pipe by backflow pipe; The medium-pressure cylinder is communicated with deaerator, the deaerator outlet is provided with feed water pump, the feed water pump outlet is provided with water conduit, and the water conduit is communicated and arranged with the hot press.

2. The energy system of claim 1, wherein, The first check valve, the first regulating valve and the first isolation valve are sequentially arranged on the main flow guide pipe along the direction from the main steam pipe to the small steam turbine.

3. The energy system of claim 1, wherein, The compressed gas assembly includes the first compressor drivingly connected with the small steam turbine, the compressor is communicated with gas source pipe, the gas source pipe is communicated and arranged with compressed gas source, and the first compressor outlet is communicated with gas product pipe.

4. The energy system of claim 1, wherein, The second check valve, the second regulating valve and the second isolation valve are sequentially arranged on the drive steam pipe along the direction from the main steam pipe to the hot press.

5. The energy system of claim 1, wherein, The third regulating valve is arranged on the backflow pipe at the position between the hot press and the cold reheat steam pipe.

6. The energy system of claim 3, wherein, The gas source pipe is communicated and arranged with the second compressor, and the second compressor is arranged as electric compressor.

7. The energy system of claim 3, wherein, The small steam turbine and the first compressor are drivingly connected by steam drive shaft.

8. The energy system of claim 1, wherein, The exhaust steam pressure in the exhaust pipe is 1-2MPa.

Images