Starting preheating system for steam generator of photo-thermal power station

Abstract

The utility model discloses a steam generator starting preheating system of a photo-thermal power station, relates to the technical field of natural circulation steam generators, and solves the problem of cold-state starting preheating of a steam generator system. A steam pocket, an evaporator and a preheater are sequentially arranged in the height direction from top to bottom; the upper side of the preheater communicates with the steam pocket through a pipeline; the upper side of the evaporator is connected with the lower side of the steam pocket through an ascending pipe; the preheating cycle starting bypass comprises a main path and two branches, the main path is connected with the steam pocket, and the main path is connected with the evaporator and the preheater through the two branches; a heater is arranged on the main circuit. The boiler water in the steam pocket, the evaporator and the preheater is continuously and circularly heated through the arranged starting preheating circulating bypass, the boiler water is heated into saturated steam water, part of the generated saturated steam is discharged to heat the superheater and the reheater, and starting preheating of all equipment is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to natural circulation steam generator technical field, specifically is a kind of photovoltaic power station steam generator starting preheating system. BACKGROUND

[0002] In solar thermal power industry, molten salt is often used as intermediate medium to store and release energy. Since molten salt will solidify at ~220℃, all the equipment in contact with molten salt medium needs to be kept at a temperature not lower than 220℃ when working. The steam generator system of photovoltaic power is one of such equipment on the energy release side, which uses high-temperature molten salt from molten salt tank to heat feed water, to generate superheated steam to enter steam turbine to do work and generate electricity.

[0003] The natural circulation steam generator system is composed of preheater, evaporator, steam drum, superheater and reheater, among which the preheater and evaporator are water-molten salt heat exchangers, the superheater and reheater are steam-molten salt heat exchangers, and the steam drum is a water storage and steam-water separation device. When using natural circulation system, the evaporator-steam drum is powered by natural circulation, without additional forced circulation pump.

[0004] When the steam generator system is working normally, the temperature of feed water is ~250℃, which meets the temperature requirement. However, when starting in cold state, the temperature of all equipment is normal temperature (~20℃), and the temperature of water injection is only ~15℃. Therefore, a separate starting preheating system is needed to preheat the equipment of natural circulation steam generator system. SUMMARY

[0005] The utility model discloses a kind of photovoltaic power station steam generator starting preheating systems to solve the problem of the above-mentioned steam generator system cold-state starting preheating.

[0006] The utility model discloses a kind of photovoltaic power station steam generator starting preheating systems, specifically including steam drum, evaporator and preheater, steam drum, evaporator and preheater are sequentially arranged from top to bottom in height direction;Preheater lower side is provided with water inlet, and upper side is communicated with steam drum by pipeline;Steam drum lower side is connected with the lower side of evaporator by downcomer, and the upper side of evaporator is connected with the lower side of steam drum by riser;Steam drum lower side is also connected with evaporator and preheater respectively by starting preheating circulation bypass;Starting preheating circulation bypass includes main road and two branches, and main road is connected with steam drum, and main road is connected with evaporator and preheater respectively by two branches;Heater is arranged on main road.

[0007] Further, gate valve and circulating water pump are also arranged on the main road, and steam drum, gate valve, circulating water pump and heater are sequentially communicated.

[0008] Further, gate valve is arranged on the branch.

[0009] Further, a gate valve is arranged on the water inlet pipeline of the preheater.

[0010] Further, a gate valve is arranged at the outlet of the steam drum.

[0011] The beneficial effect of the light and heat power station steam generator starting preheating system is:

[0012] (1) The light and heat power station steam generator starting preheating system solves the problem of cold-state starting preheating of the steam generator system, continuously circulates and heats the boiler water in the steam drum, evaporator and preheater through the starting preheating circulating bypass, the boiler water is heated into saturated steam water, and the generated saturated steam is discharged to heat the superheater and reheater, thereby realizing starting preheating of all devices. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings, and their description, are presented to add generic structure for public inspection in order to convey an understanding of the application.

[0014] In the drawings:

[0015] Figure 1 is a structural schematic view of the light and heat power station steam generator starting preheating system according to the present application;

[0016] Wherein: 1-gate valve two, 2-steam drum, 3-down pipe, 4-up pipe, 5-gate valve three, 6-circulating water pump, 7-heater, 8-evaporator, 9-gate valve four, 10-gate valve five, 11-preheater, 12-gate valve one. DETAILED DESCRIPTION

[0017] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0018] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] Specific implementation method one: See Figure 1 This implementation method will be described in detail. For example... Figure 1 The diagram shows a preheating system for the start-up of a solar thermal power plant steam generator according to this embodiment. The solid line represents the normal operating feedwater line, and the dashed line represents the preheating cycle bypass. Specifically, the preheating system includes a steam drum 2, an evaporator 8, and a preheater 11, arranged sequentially from top to bottom in the vertical direction. The preheater 11 has a water inlet on its lower side and is connected to the steam drum 2 via a pipeline on its upper side. The lower side of the steam drum 2 is connected to the lower side of the evaporator 8 via a downcomer 3, and the upper side of the evaporator 8 is connected to the lower side of the steam drum 2 via a riser 4. The lower side of the steam drum 2 is also connected to both the evaporator 8 and the preheater 11 via the preheating cycle bypass. The preheating cycle bypass includes a main line and two branch lines. The main line is connected to the steam drum 2, and the two branch lines are connected to both the evaporator 8 and the preheater 11. A heater 7 is installed on the main line.

[0022] The main line is also equipped with gate valve 3 (5) and circulating water pump 6, and steam drum 2, gate valve 3 (5), circulating water pump 6 and heater 7 are connected in sequence. One branch line is equipped with gate valve 4 (9) and is connected to the inlet of evaporator 8; another branch line is equipped with gate valve 5 (10) and is connected to the inlet of preheater 11.

[0023] A gate valve 12 is installed on the water inlet pipe of the preheater 11.

[0024] A gate valve 2 is installed at the steam outlet of the steam drum 2.

[0025] When the steam generator is in normal operation, the preheater 11 feeds water into the steam drum 2, the saturated water in the steam drum 2 is circulated into the evaporator 8 through the downcomer 3 to be evaporated, the evaporated saturated steam and water are separated in the steam drum 2 through the riser 4, and the superheated steam is fed into the superheater to be superheated. Figure 1 The normal operation water feeding line.

[0026] The start-up preheating circulation bypass is arranged in communication with the normal operation water feeding line, and together forms a start-up preheating system to realize the start-up preheating function: the circulating water pump 6 is used to draw the boiler water in the steam drum 2 from the bottom of the steam drum 2 into the heater 7 to be heated, and the heated boiler water is divided into two paths and fed into the inlet of the preheater 11 and the inlet of the evaporator 8 connected with the downcomer 3. The circulating water entering the preheater 11 is returned to the steam drum 2 through the normal water feeding line, and the circulating water entering the evaporator 8 is returned to the steam drum 2 through the riser 4 and flows in the downcomer 3 under the action of the height difference.

[0027] The specific working process of the start-up preheating system of the photothermal power station steam generator is explained as follows:

[0028] The gate valve one 12 at the inlet of the preheater 11 and the gate valve two 1 at the outlet of the steam drum 2 are closed to form a closed system of the preheater 11, the evaporator 8 and the steam drum 2; the gate valve three 5, the gate valve four 9 and the gate valve five 10 of the start-up preheating circulation bypass are opened to communicate the normal operation water feeding line and the start-up preheating circulation bypass; the circulating water pump 6 and the heater 7 are opened to continuously heat the circulating boiler water; as the temperature of the boiler water is higher and higher, the boiler water is heated into saturated steam and water by the heater 7 after reaching the saturated temperature (i.e. 100℃ under atmospheric pressure), and the saturated steam is returned to the steam drum 2 to cause the system to gradually increase the pressure and temperature due to the pressure of the closed system; as the system pressure increases, the gate valve two 1 at the outlet of the steam drum 2 is slightly opened to release part of the saturated steam to heat the superheater and the reheater; when the temperature of all the devices reaches 240℃ or above, the start-up preheating circulation bypass is cut off to complete the start-up preheating of the system.

[0029] The start-up preheating system of the photothermal power station steam generator solves the problem of cold-state start-up preheating of the steam generator system, continuously heats the boiler water in the steam drum 2, the evaporator 8 and the preheater 11 through the start-up preheating circulation bypass, heats the boiler water into saturated steam and water, releases part of the generated saturated steam to heat the superheater and the reheater, and realizes the start-up preheating of all the devices.

[0030] The above-described specific embodiments further specifically describe the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above-described specific embodiments are merely examples of the present application and are not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A start-up pre-heat system for a thermal power plant steam generator, characterized by: The application relates to a steam generator comprising a steam drum (2), an evaporator (8) and a preheater (11), wherein the steam drum (2), the evaporator (8) and the preheater (11) are sequentially arranged from top to bottom in the height direction; the preheater (11) is provided with a water inlet on the lower side and is communicated with the steam drum (2) through a pipeline on the upper side; the lower side of the steam drum (2) is connected with the lower side of the evaporator (8) through a downcomer (3); the upper side of the evaporator (8) is connected with the lower side of the steam drum (2) through an upcomer (4); the lower side of the steam drum (2) is further connected with the evaporator (8) and the preheater (11) through a start-up preheating circulation bypass; the start-up preheating circulation bypass comprises a main path and two branch paths; the main path is connected with the steam drum (2); the main path is connected with the evaporator (8) and the preheater (11) through the two branch paths; and a heater (7) is arranged on the main path.

2. The photo-thermal power plant steam generator start-up pre-heat system of claim 1, wherein: A gate valve and a circulating water pump (6) are further arranged on the main path; the steam drum (2), the gate valve, the circulating water pump (6) and the heater (7) are sequentially communicated.

3. The photo-thermal power plant steam generator start-up pre-heat system of claim 1, wherein: A gate valve is arranged on the branch path.

4. The photo-thermal power plant steam generator start-up pre-heat system of claim 1, wherein: A gate valve is arranged on the water inlet pipeline of the preheater (11).

5. The photo-thermal power plant steam generator start-up pre-heat system of claim 1, wherein: A gate valve is arranged at the outlet of the steam drum (2).

Images