Condensing unit low-pressure heat supply transformation system

Abstract

The utility model discloses a condensing unit low-pressure heat supply transformation system which comprises a low-pressure cylinder, an intermediate-pressure cylinder and a high-pressure cylinder, the high-pressure cylinder is connected with a main steam pipeline, the intermediate-pressure cylinder is connected with a reheat steam pipeline, and the intermediate-pressure cylinder is connected with the low-pressure cylinder through a second steam pipeline and a second branch pipeline. The medium-pressure cylinder is connected with the heat supply network heater through a second steam pipeline and a first branch pipeline, steam from the medium-pressure cylinder passes through the heat supply network heater, then condensed water is connected with a large machine heat regeneration system, the heat supply network circulating pump is connected with the heat supply network heater, and cold water passes through the heat supply network circulating pump, is subjected to heat exchange through the heat supply network heater and then goes to heat consumers. In order to overcome the defects in the prior art, the utility model provides the low-pressure heat supply transformation system of the condensing unit. Under the condition that heat supply requirements are met, heat supply safety and reliability are high, economical efficiency is good, heat supply transformation cost is reduced, and operation risks are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of low-pressure heating transformation of condensing units in power plants, and in particular to a low-pressure heating transformation system for condensing units. The utility model can improve the heating capacity, heating safety and economy of the units. Background Art

[0002] In the existing technology, the unit often uses low-pressure cylinder zero-output technology to carry out heating steam transformation. Low-pressure cylinder zero-output transformation is also called cylinder cutting transformation. It is a heating technology that uses most of the exhaust steam from the intermediate-pressure cylinder for heating, and passes a very small amount of exhaust steam into the low-pressure cylinder to take away the blast heat of the low-pressure blades.

[0003] The existing technology involves a large amount of work in cylinder cutting and modification, and there are certain safety risks in operation. When the low-pressure cylinder is modified to "zero output", when it is operated under small volume flow conditions, the last two stages of the low-pressure cylinder are operated under blast conditions, which causes the temperature after the last two stages of the low-pressure cylinder and the temperature of the low-pressure exhaust cylinder to increase. In order to reduce the temperature of the low-pressure exhaust cylinder, it is necessary to continuously spray water to reduce the temperature and maintain the temperature of the low-pressure exhaust cylinder within a safe range. Under small volume flow conditions, the vortex appearing on the last-stage blades will draw cooling water into the moving blade flow channel, aggravating the water erosion in the root area of ​​the moving blade steam outlet edge, threatening the safe operation of the unit. In other words, when the low-pressure cylinder is running at zero output, there may be problems such as blade blasting, flutter, and aggravated water erosion. Therefore, it is necessary to apply a metal wear-resistant layer spraying treatment to the last-stage blades of the low-pressure cylinder. Utility Model Content

[0004] The utility model is to overcome the shortcomings of the above-mentioned prior art and provide a low-pressure heat supply transformation system for a condensing unit. The utility model can improve the heating capacity of the unit, and under the condition of meeting the heating requirements, the heating safety and reliability are high, the economy is good, the heating transformation cost is reduced, and the operation risk is reduced.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A low-pressure heating reconstruction system for a condensing unit comprises a low-pressure cylinder, an intermediate-pressure cylinder and a high-pressure cylinder, wherein the high-pressure cylinder is connected to a main steam pipeline, the intermediate-pressure cylinder is connected to a reheat steam pipeline, the intermediate-pressure cylinder is connected to the low-pressure cylinder via a second steam pipeline and a second branch pipeline, the intermediate-pressure cylinder is connected to a heat network heater via a second steam pipeline and a first branch pipeline, the steam from the intermediate-pressure cylinder passes through the heat network heater and the condensed water is connected to a large machine heat recovery system, the heat network circulation pump is connected to the heat network heater, and cold water passes through the heat network circulation pump and is heat exchanged in the heat network heater before being sent to heat users.

[0007] The second branch pipeline is connected to the air intake pipeline.

[0008] The air intake pipeline is provided with a flow meter and a steam intake control valve.

[0009] A regulating valve is provided on the branch pipe 2 connecting the medium-pressure cylinder and the low-pressure cylinder, and the amount of steam entering the low-pressure cylinder is regulated by the regulating valve.

[0010] There is a tee in front of the regulating valve. The steam is led out from the tee and connected to the heating network heater, and then goes to the heat user.

[0011] The branch pipeline 1 is provided with a valve 1, and the steam extraction pressure is adjusted by the regulating valve. The branch pipeline 1 is used to adjust the steam supply to the outside.

[0012] The beneficial effects of the utility model are:

[0013] 1. The utility model can reduce the amount of steam turbine body modification work while ensuring that the volume flow of the low-pressure cylinder of the steam turbine is not lower than the safety volume flow of the original unit, and avoid the operating risk caused by too little steam flow in the low-pressure cylinder. At the same time, the utility model increases the steam extraction capacity of the unit by cutting off most of the steam inlet of the low-pressure cylinder of the steam turbine while ensuring that the volume flow of the low-pressure cylinder of the steam turbine is not lower than the safety volume flow of the original unit.

[0014] 2. The low-pressure cylinder of the utility model maintains a certain steam flow rate. At this time, there is no need to implement metal wear-resistant layer spraying treatment on the last-stage blades of the low-pressure cylinder, and the transformation workload is small, thereby reducing the workload and cost of the low-pressure cylinder transformation.

[0015] 3. The low-pressure cylinder of the utility model maintains a certain steam flow rate, avoiding problems such as blade blasting, flutter, and increased water erosion that may exist during operation. The volume flow of the low-pressure cylinder of the utility model meets the safe volume flow of the original unit, has high operational safety, and reduces operational safety risks.

[0016] 4. By providing a valve 1 on the branch pipe 1, the extraction steam pressure is adjusted by the regulating valve, and the external steam supply can be conveniently and accurately adjusted through the branch pipe 1.

[0017] 5. By providing a regulating valve on the branch pipe 2 connecting the medium-pressure cylinder and the low-pressure cylinder, the amount of steam entering the low-pressure cylinder can be conveniently and accurately regulated through the regulating valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0019] Figure 1 It is a schematic structural diagram of an embodiment of the present utility model.

[0020] In the figure, low-pressure cylinder 1, medium-pressure cylinder 2, high-pressure cylinder 3, generator 4, steam pipe 2 8, branch pipe 2 9, branch pipe 1 10, air intake pipe 11, heating network heater 12, heating network circulating pump 13, heat user 14, large machine heat recovery system 15, steam inlet control valve 16, flow meter 17, main steam pipe 18, reheat steam pipe 19, valve 1 20, valve 2 21, and tee 22. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0022] like Figure 1 As shown, a low-pressure heating reconstruction system for a condensing unit includes a low-pressure cylinder 1, an intermediate-pressure cylinder 2, and a high-pressure cylinder 3. The high-pressure cylinder 3 is connected to a main steam pipe 18, the intermediate-pressure cylinder 2 is connected to a reheat steam pipe 19, the intermediate-pressure cylinder 2 is connected to the low-pressure cylinder 1 through a steam pipe 2 8 and a branch pipe 2 9, the intermediate-pressure cylinder 2 is connected to a heat network heater 12 through a steam pipe 2 8 and a branch pipe 10, the steam from the intermediate-pressure cylinder 2 passes through the heat network heater 12 and the condensed water is connected to a large machine heat recovery system 15, the heat network circulation pump 13 is connected to the heat network heater 12, and the cold water passes through the heat network circulation pump 13 and is heat exchanged through the heat network heater 12 and then goes to the heat user 14.

[0023] The branch pipeline 2 9 is connected to the air intake pipeline 11 .

[0024] The air intake pipe 11 is provided with a flow meter 17 and a steam intake control valve 16 .

[0025] A regulating valve 21 is provided on the branch pipe 29 connecting the medium pressure cylinder 2 and the low pressure cylinder 1. The regulating valve 21 is used to adjust the amount of steam entering the low pressure cylinder 1.

[0026] A tee 22 is provided in front of the regulating valve 21. Steam is drawn out from the tee 22 and connected to the heating network heater 12, and then goes to the heat user 14 to realize steam extraction heating of the steam turbine.

[0027] The branch pipeline 10 is provided with a valve 20, and the steam extraction pressure can be adjusted by the regulating valve 20. The branch pipeline 10 is used to adjust the external steam supply.

[0028] The utility model can reduce the amount of steam turbine body modification work while avoiding the operating risk caused by too little steam flow in the low-pressure cylinder, on the premise of ensuring that the volume flow of the low-pressure cylinder of the steam turbine is not lower than the safe volume flow of the original unit. At the same time, the utility model increases the steam extraction capacity of the unit by cutting off most of the steam inlet of the low-pressure cylinder of the steam turbine, on the premise of ensuring that the volume flow of the low-pressure cylinder of the steam turbine is not lower than the safe volume flow of the original unit.

[0029] 2. The low-pressure cylinder of the utility model maintains a certain steam flow rate. At this time, there is no need to implement metal wear-resistant layer spraying treatment on the last-stage blades of the low-pressure cylinder, and the transformation workload is small, thereby reducing the workload and cost of the low-pressure cylinder transformation.

[0030] 3. The low-pressure cylinder of the utility model maintains a certain steam flow rate, avoiding problems such as blade blasting, flutter, and increased water erosion that may exist during operation. The volume flow of the low-pressure cylinder of the utility model meets the safe volume flow of the original unit, has high operational safety, and reduces operational safety risks.

[0031] In the description of the present invention, the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "vertical", "horizontal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the purpose of describing the present invention rather than requiring the present invention to be constructed or operated in a specific position, and therefore cannot be understood as a limitation on the present invention. The terms "connected" and "connected" in the present invention should be understood in a broad sense, for example, it can be a connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] The above is a preferred embodiment of the present invention, and the description of the specific embodiment is only used to better understand the concept of the present invention. For ordinary technicians in this technical field, several improvements or equivalent substitutions can be made according to the principle of the present invention, and these improvements or equivalent substitutions are also considered to fall within the protection scope of the present invention.

Claims

1. A low-pressure heating transformation system for a condensing unit, comprising a low-pressure cylinder, a medium-pressure cylinder, and a high-pressure cylinder, characterized in that: The high-pressure cylinder is connected to the main steam pipeline, the medium-pressure cylinder is connected to the reheat steam pipeline, the medium-pressure cylinder is connected to the low-pressure cylinder through steam pipeline 2 and branch pipeline 2, the medium-pressure cylinder is connected to the heat network heater through steam pipeline 2 and branch pipeline 1, the steam from the medium-pressure cylinder passes through the heat network heater and the condensed water is connected to the large machine heat recovery system, the heat network circulation pump is connected to the heat network heater, and the cold water passes through the heat network circulation pump and heat exchanged with the heat network heater before going to the heat user.

2. The low-pressure heat supply transformation system of a condensing unit according to claim 1 is characterized in that: The second branch pipeline is connected to the air intake pipeline.

3. The low-pressure heat supply transformation system for a condensing unit according to claim 2 is characterized in that: The air intake pipeline is provided with a flow meter and a steam intake control valve.

4. The low-pressure heat supply transformation system for a condensing unit according to claim 1, characterized in that: A regulating valve is provided on the branch pipe 2 connecting the medium-pressure cylinder and the low-pressure cylinder, and the amount of steam entering the low-pressure cylinder is regulated by the regulating valve.

5. The low-pressure heat supply transformation system for a condensing unit according to claim 4 is characterized in that: There is a tee in front of the regulating valve. The steam is led out from the tee and connected to the heating network heater, and then goes to the heat user.

6. The low-pressure heat supply transformation system for a condensing unit according to claim 1, characterized in that: A valve is provided on the branch pipeline one, and the extraction steam pressure is adjusted by the regulating valve.

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