Low-pressure bypass system matched with deep peak regulation of unit

Abstract

The utility model relates to the field of low-pressure bypass systems, in particular to a low-pressure bypass system matched with deep peak regulation of a unit, which comprises a valve seat main body, a valve seat valve core is mounted in the valve seat main body, a pre-starting valve changing gasket is arranged on the outer wall of the valve seat valve core, and a valve seat connecting pipe is arranged on the other side of the valve seat main body. A valve flow pipe is arranged on one side of the valve seat body, and a flow adjusting hole is formed in the valve flow pipe. According to the utility model, the valve core protective sleeve is arranged, and the low side valve core is transformed into the valve core with the protective sleeve, so that wet steam of the valve can be prevented from being directly scoured on the valve core, the special protective sleeve is arranged on the valve core, the valve core is reliably prevented from being damaged by blowing, the problem of inner leakage of deep peak regulation low side scour is solved, the coal consumption of a unit is reduced, and the efficiency of the unit is improved; the safety reliability and peak regulation flexibility of the system are improved after transformation, and safe and stable operation of the unit is guaranteed.

Description

Technical Field

[0001] The utility model relates to the field of low-pressure bypass systems, in particular to a low-pressure bypass system for deep peak regulation of a unit. Background Art

[0002] The bypass system of the unit is configured as a high-pressure and low-pressure two-stage series bypass with a capacity of 30% BMCR. The bypass device consists of a high-pressure bypass system and two low-pressure bypass systems. The low-pressure bypass system consists of a low-pressure bypass valve, a water spray regulating valve, a water spray isolation valve, a desuperheater, etc. It is connected from the reheat steam pipeline in front of the inlet of the intermediate-pressure cylinder of the steam turbine, and is connected to the condenser after pressure reduction and temperature reduction. With the frequent deep peak regulation of the unit in recent years, the low-pressure bypass valve is frequently opened and closed, which brings the following three problems: First, the pipeline behind the low-pressure bypass valve is eroded and thinned, and there is a risk of leakage; second, the low-pressure bypass valve and the drain gate in front of the low-pressure bypass valve are frequently eroded and leaked; third, during the deep peak regulation period, the steam temperature before the low bypass reaches the rated reheat steam temperature of 566 degrees Celsius, which is about 100 degrees Celsius higher than the reheat steam temperature during start-up and shutdown, and the strength margin of the low bypass valve cover bolts is insufficient.

[0003] In Chinese patent CN114542219B, the present invention provides a system for low-pressure bypass heat storage peak regulation of a heating power generation unit, which is used for the heating power generation unit to achieve deep peak regulation in both the heat storage and heat release stages. The system combines the low-pressure bypass with the heat storage device, connects the boiler reheater with the heat storage device through the low-pressure bypass steam pipeline and the low-pressure bypass steam regulating valve. When the heating power generation unit needs to be peak shaving, the low-pressure bypass and the heat storage device are enabled, and the unit can achieve deep load reduction peak regulation in both the heat storage and heat release stages. Through repeated heat storage and heat release, less heat storage medium can be used to achieve continuous long-term peak regulation; due to the combination of the low-pressure bypass system and the heat storage device, the high-temperature and high-pressure steam in the low-pressure bypass passes through the heat storage device and the temperature and pressure reduction device before outputting the heating steam to the user for heating, thereby reducing part of the energy loss in the high-quality steam temperature reduction process; at the same time, because the system is not completely thermoelectrically decoupled, a certain system thermal efficiency is also guaranteed.

[0004] In the existing low-pressure bypass system, the unit frequently performs deep peak regulation. After the low-pressure bypass valve is opened for a long time, the pipeline behind the low-pressure bypass valve is eroded and thinned. In addition, the metallographic structure of the pipeline behind the valve may change due to overheating and other reasons, which reduces the strength of the material and seriously affects the safe operation of the unit. Other units in the system have experienced accidents in which the pipeline behind the valve ruptures during operation. Analysis shows that this is because the grade of the material behind the valve is low and the strength is insufficient after overheating. In recent years, the unit has frequently performed peak regulation. Through long-term tracking and degradation analysis of the pipeline and fittings behind the low bypass, it is found that the pipeline and fittings made of Q235-A thin at a faster rate. The unit frequently performs deep peak regulation, and the low-pressure bypass valve system is frequently opened and closed, resulting in frequent erosion and leakage of the low-pressure bypass valve and the drain gate in front of the low-pressure bypass valve. The internal leakage of the low-pressure bypass system increases the heat consumption rate of the unit, which has a great impact on the economy of the unit. The long-term existence of internal leakage also poses a serious hidden danger to the safety of the unit.

[0005] Therefore, to address the above issues, a low-pressure bypass system is proposed for deep peak regulation of the units. Utility Model Content

[0006] In order to make up for the deficiencies of the prior art and to make the low-pressure bypass system have a better cooling effect, the utility model provides a low-pressure bypass system for deep peak regulation of the unit, which solves the problems of the existing low-pressure bypass system, that is, the water temperature may be high due to hot weather when in use, thereby failing to effectively cool down the processed parts and tools during cooling, and the cooling method is single.

[0007] The technical solution adopted by the utility model to solve its technical problems is: the low-pressure bypass system for deep peak regulation of the unit described in the utility model comprises a valve seat body, a valve seat valve core is installed inside the valve seat body, and a pre-start valve replacement gasket is arranged on the outer wall of the valve seat valve core, and a valve seat connecting pipe is arranged on the other side of the valve seat body, a valve flow tube is arranged on one side of the valve seat body, and a flow regulating hole is opened inside the valve flow tube, a valve core protection sleeve is arranged on one side of the flow regulating hole, and a core surface sealing surface is arranged on the other side of the valve core protection sleeve, a clamping ring is arranged on the other side of the valve seat body, and a spring washer is tightly fitted on the other side of the clamping ring, and the internal thread of the clamping ring is connected with a hexagon socket bolt, the valve flow tube is made of A335-P22 alloy, and the valve flow tube and the outer wall of the valve core protection sleeve are in a vertical parallel line, and the valve core protection sleeve is made of Stellite alloy.

[0008] Preferably, the flow regulating hole flows through the valve core protection sleeve and then indirectly flows to the core surface sealing surface.

[0009] Preferably, the hexagon socket bolt forms an elastic structure through a spring washer and a clamping ring, and the hexagon socket bolt is made of Inconell718 alloy.

[0010] Preferably, the pre-start valve replacement gasket is made of high carbon steel.

[0011] Preferably, the two core sealing surfaces in the same area are symmetrically arranged to form a smaller groove.

[0012] The benefits of utility models are:

[0013] 1. The utility model is provided with a valve core protection sleeve, and the low bypass valve core is transformed into a valve core with a protection sleeve. This method can ensure that the valve wet steam does not directly flush on the valve core. There is a special protection sleeve on the valve core, which reliably ensures that the valve core is not damaged by blowing, solves the problem of internal leakage caused by flushing of the low bypass during deep peak regulation, and the low-pressure bypass valve can fully meet the no internal leakage standard, reduce the coal consumption of the unit, and improve the efficiency of the unit. At the same time, after the transformation, the system safety reliability and peak regulation flexibility are improved, ensuring the safe and stable operation of the unit;

[0014] 2. The utility model is provided with a valve flow tube, and the valve flow tube and valve seat connecting tube made of A335-P22 alloy are used. The material of all pipelines and pipe fittings between the low bypass and the low bypass three-stage desuperheater is upgraded to A335-P22 alloy, thereby improving the material grade and solving the problem of rapid thinning of pipelines and pipe fittings after the low bypass valve due to deep peak regulation of the unit. The mixed temperature zone of the pipeline after the low-pressure bypass valve is consistent with the material before the valve, thus ensuring the safe operation of the pipeline after the valve after the low-pressure bypass valve is opened during the peak regulation of the unit;

[0015] 3. The utility model is provided with hexagon socket bolts, and the material of the low bypass valve cover bolts is upgraded to Inconel718 alloy, thereby solving the problem of insufficient strength margin of the original material of the low bypass valve cover bolts. The strength of the low-pressure bypass valve cover bolts is improved, which can meet the requirement that the reheat steam temperature reaches the rated value during deep peak regulation, thereby ensuring the safe operation of the low-pressure bypass valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the utility model;

[0018] Figure 2 for Figure 1 A schematic diagram of the enlarged three-dimensional structure of the structure at A in the middle;

[0019] Figure 3 for Figure 1Schematic diagram of the enlarged three-dimensional structure of the structure at B in the middle.

[0020] In the figure: 1. Valve seat body; 2. Valve seat valve core; 3. Pre-start valve replacement gasket; 4. Valve flow tube; 5. Flow adjustment hole; 6. Valve core protection sleeve; 7. Core sealing surface; 8. Clamping ring; 9. Spring washer; 10. Hexagon socket bolt; 11. Valve seat connecting pipe. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] Embodiment 1

[0023] See also Figures 1 to 3 As shown, the low-pressure bypass system for deep peak regulation of the unit includes a valve seat body 1, a valve seat valve core 2 is installed inside the valve seat body 1, and a pre-start valve replacement gasket 3 is arranged on the outer wall of the valve seat valve core 2, and a valve seat connecting pipe 11 is arranged on the other side of the valve seat body 1, a valve flow tube 4 is arranged on one side of the valve seat body 1, and a flow regulating hole 5 is opened inside the valve flow tube 4, a valve core protection sleeve 6 is arranged on one side of the flow regulating hole 5, and a core surface sealing surface 7 is arranged on the other side of the valve core protection sleeve 6, a clamping ring 8 is arranged on the other side of the valve seat body 1, and a spring washer 9 is tightly fitted on the other side of the clamping ring 8, and the internal thread of the clamping ring 8 is connected with a hexagon socket bolt 10, the material of the valve flow tube 4 is A335-P22 alloy, and the valve flow tube 4 It is in a vertical parallel line with the outer wall of the valve core protection sleeve 6, and the material of the valve core protection sleeve 6 is Stellite alloy; during the operation of the equipment, the valve flow tube 4 components in the valve seat body 1 flush steam toward the core surface sealing surface 7 through the internal flow adjustment hole 5. There is a special valve core protection sleeve 6 on the valve core. The valve flow tube 4 and the valve core protection sleeve 6 are arranged vertically. The valve core protection sleeve 6 must be flushed first before steam enters the core surface sealing surface 7, which reliably ensures that the valve seat valve core 2 is not damaged by blowing, and solves the problem of internal leakage caused by deep peak regulation and low bypass flushing. During the steam flushing process, the valve flow tube 4, valve seat connecting pipe 11 and other pipelines made of A335-P22 alloy are used to improve the material grade and solve the problem of rapid thinning of pipelines and fittings after the deep peak regulation and low bypass valve of the unit.

[0024] See also Figure 2 and Figure 3As shown, the flow through the flow regulating hole 5 flows to the valve core protection sleeve 6 and then indirectly flows to the core surface sealing surface 7; the steam first contacts the valve core protection sleeve 6 through the internal flow regulating hole 5, and the valve core protection sleeve 6 ensures that the wet steam of the valve will not directly wash the valve core, and then contacts the core surface sealing surface 7.

[0025] See also Figure 1 As shown, the hexagon socket bolt 10 forms an elastic structure through the spring washer 9 and the clamping ring 8, and the material of the hexagon socket bolt 10 is Inconel718 alloy; the hexagon socket bolt 10 made of higher strength Inconel718 alloy inside the valve seat body 1 solves the problem of insufficient strength margin of the original material of the low bypass valve cover bolt, and cooperates with the clamping ring 8 and the spring washer 9 to effectively extend the overall service life.

[0026] See also Figure 1 As shown, the material of the pre-start valve replacement gasket 3 is high carbon steel; since the valve is frequently opened, the sealing ring is easily damaged during frequent openings. If the bolt strength is high enough, the control gasket can be replaced with a spring to become a pre-self-starting structure to meet the use requirements.

[0027] See also Figure 2 and Figure 3 As shown, the two core surface sealing surfaces 7 in the same area are symmetrically arranged to form a smaller groove; after passing through the valve flow tube 4 and the valve core protection sleeve 6, the steam passes through the groove formed by the two core surface sealing surfaces 7 and then enters the valve seat valve core 2.

[0028] Working principle: First, during the operation of the equipment, the valve flow tube 4 in the valve seat body 1 flushes steam toward the core surface sealing surface 7 through the internal flow adjustment hole 5. The steam first contacts the valve core protection sleeve 6 through the internal flow adjustment hole 5. The valve core protection sleeve 6 ensures that the valve wet steam will not directly flush on the valve core. Then it contacts the core surface sealing surface 7, and enters the valve seat core 2 through the groove formed by the two core surface sealing surfaces 7. There is a special valve core protection sleeve 6 on the valve core, which reliably ensures that the valve seat core 2 is not damaged by blowing, and solves the problem of internal leakage caused by deep peak regulation and low bypass flushing. During the steam flushing process, the valve flow tube 4, valve seat connecting pipe 11 and other pipelines made of A335-P22 alloy are used to improve the material grade and solve the problem of internal leakage caused by machine The problem of rapid thinning of pipelines and fittings after the deep peak-shaving low bypass valve is solved, so that the equipment can operate continuously and avoid accidents of pipeline rupture during operation. During the deep peak-shaving period, the steam temperature before the low bypass reaches the rated reheat steam temperature of 566℃, which is about 100℃ higher than the reheat steam temperature during start-up and shutdown. The original material of the low bypass valve cover bolts is A193-B16, and the strength margin is insufficient. The hexagon socket bolts 10 made of higher strength Inconel718 alloy are used inside the valve seat body 1 to solve the problem of insufficient strength margin of the original material of the low bypass valve cover bolts. The clamping ring 8 and spring washer 9 are used to effectively extend the overall service life. In addition, an elastic pre-start valve replacement gasket 3 is used around the valve seat valve core 2, and the hexagon socket bolts 10 with sufficient strength are used to change the whole structure to a pre-start valve structure.

[0029] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, and these changes and improvements fall within the scope of the utility model to be protected.

Claims

1. The unit's deep peak load regulation is equipped with a low-pressure bypass system, which is characterized by: The valve seat body (1) comprises a valve seat core (2) installed inside the valve seat body (1), and a pre-start valve replacement gasket (3) is arranged on the outer wall of the valve seat core (2), and a valve seat connecting pipe (11) is arranged on the other side of the valve seat body (1), a valve flow tube (4) is arranged on one side of the valve seat body (1), and a flow regulating hole (5) is opened inside the valve flow tube (4), a valve core protection sleeve (6) is arranged on one side of the flow regulating hole (5), and a core surface sealing surface (7) is arranged on the other side of the valve core protection sleeve (6), a clamping ring (8) is arranged on the other side of the clamping ring (8), and a spring washer (9) is tightly fitted on the other side of the clamping ring (8), and a hexagon socket head bolt (10) is connected to the internal thread of the clamping ring (8); The material of the valve flow tube (4) is A335-P22 alloy, the valve flow tube (4) and the outer wall of the valve core protection sleeve (6) are in a vertical parallel line, and the material of the valve core protection sleeve (6) is Stellite alloy.

2. The low-pressure bypass system for deep peak load regulation of the unit according to claim 1 is characterized by: The flow regulating hole (5) flows through the valve core protection sleeve (6) and then indirectly flows to the core surface sealing surface (7).

3. The low-pressure bypass system for deep peak load regulation of the unit according to claim 1 is characterized by: The hexagon socket bolt (10) forms an elastic structure through a spring washer (9) and a clamping ring (8), and the material of the hexagon socket bolt (10) is Inconel718 alloy.

4. The low-pressure bypass system for deep peak load regulation of the unit according to claim 1 is characterized in that: The material of the pre-start valve replacement gasket (3) is high carbon steel.

5. The low-pressure bypass system for deep peak load regulation of the unit according to claim 1 is characterized by: Two core sealing surfaces (7) in the same area are symmetrically arranged to form a smaller groove.

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