Multi-heat-exchanger parallel integrated configuration steam generator system of photo-thermal power station

Abstract

According to the multi-heat-exchanger parallel integrated configuration steam generator system of the photo-thermal power station, when the unit capacity is increased and a heat exchanger with standard capacity cannot be directly adopted, the whole set of unit does not need to be redesigned by consuming too much manpower and material resources, so that the research and development investment of equipment can be saved; meanwhile, auxiliary devices such as a flow valve can be reduced, fault points are reduced, and the operation and maintenance workload is reduced. The system comprises a steam-water side system and a molten salt side system, a heat exchanger of the steam-water side system comprises N preheaters, a steam pocket, N evaporators, N superheaters and N reheaters, the reheaters and the superheaters are connected with a steam turbine, the preheaters, the evaporators, the superheaters and the reheaters with the standard capacity are connected in parallel, and N is a positive integer larger than 1. N is equal to the increased target unit capacity / standard unit capacity, and the lengths and the pipe diameters of the steam-water side connecting pipelines of the N heat exchangers connected in parallel are equal.

Description

Technical Field

[0001] The present invention relates to the technical field of steam generating devices, and in particular to a steam generator system having multiple heat exchangers connected in parallel and integrated therein in a solar thermal power station. Background Art

[0002] The steam generator is a critical heat exchange system in a CSP plant. It includes equipment such as a preheater, evaporator, drum, superheater, and reheater. Currently, most CSP projects in operation in China are standard-capacity units, such as 50MW. When unit capacity increases, for example to 100MW or above, the heat exchanger equipment in the steam generator of a conventional 50MW unit can no longer meet system parameter requirements. This means that standard-capacity heat exchangers cannot be directly used, and non-standard-capacity heat exchangers need to be redesigned. Increasing the capacity of a single unit is constrained by factors such as the structural design of the unit itself, requiring significant manpower and material resources to design a new unit to meet the increased unit capacity requirements. Summary of the Invention

[0003] In response to the problem that when the unit capacity increases, it is necessary to spend manpower and material resources to redesign the unit, the present invention provides a multi-heat exchanger parallel integrated steam generator system for a solar thermal power station. When the unit capacity increases and standard capacity heat exchangers cannot be directly used, there is no need to spend too much manpower and material resources to redesign the entire unit, thereby saving equipment research and development investment. At the same time, it can also reduce auxiliary devices such as flow valves, reduce failure points, and reduce operation and maintenance workload.

[0004] The technical solution is as follows: a multi-heat exchanger parallel integrated steam generator system of a solar thermal power station, which includes a steam-water side system and a molten salt side system. The steam-water side system and the molten salt side system are equipped with heat exchangers. The heat exchanger of the steam-water side system includes a preheater, a steam drum, an evaporator, a superheater and a reheater. The reheater and the superheater are respectively connected to the steam turbine. It is characterized in that: it is suitable for the situation where the capacity of the target unit of the solar thermal power station is increased and the unit with the increased capacity cannot directly use a heat exchanger of standard capacity. The preheater, the evaporator, the superheater and the reheater of standard capacity are respectively provided with N units and are connected in parallel with each other, N is a positive integer greater than 1, and N=the increased target unit capacity / standard unit capacity, and the length and diameter of the steam-water side connecting pipes of the N parallel heat exchangers are equal.

[0005] Furthermore, the feed water is connected to the feed water inlet of the preheater in parallel, the feed water outlet of the preheater in parallel is connected to the inlet 1 of the steam drum, the outlet 1 of the steam drum is connected to the steam-water inlet of the evaporator in parallel, the steam-water outlet of the evaporator in parallel is connected to the inlet 2 of the steam drum, the outlet 2 of the steam drum is connected to the steam inlet of the superheater in parallel, the steam outlet of the superheater in parallel is connected to the steam turbine, the exhaust port of the steam turbine is connected to the steam inlet of the reheater in parallel, and the steam outlet of the reheater in parallel is connected to the steam turbine.

[0006] Furthermore, the height of the steam drum is higher than the height of the evaporator.

[0007] Furthermore, the heat exchanger of the molten salt system includes the superheater, the reheater, the evaporator and the preheater; the high-temperature molten salt is respectively connected to the molten salt inlets of N superheaters and the molten salt inlets of N reheaters, the molten salt inlet of each evaporator is connected to the molten salt outlet of one of the superheaters and the molten salt outlet of one of the reheaters, and the molten salt outlet of each evaporator is connected to the molten salt inlet of one of the preheaters.

[0008] Furthermore, the lengths and diameters of the molten salt side connecting pipes between the N evaporators and the preheaters are equal.

[0009] Beneficial effects: When the unit capacity increases, this solution can use standard-capacity heat exchangers to form non-standard-capacity units, without consuming too much manpower and material resources to redesign the entire unit, thereby saving equipment research and development investment. At the same time, this solution can reduce auxiliary devices such as flow valves while ensuring the consistency of parallel pipeline flow, thereby reducing failure points and costs, and reducing operation and maintenance workload. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the connection diagram of the steam-water side pipeline of the present invention;

[0011] Figure 2 This is the molten salt side pipeline connection diagram of the present invention. DETAILED DESCRIPTION

[0012] like Figure 1A multi-heat exchanger parallel integrated steam generator system for a solar thermal power station is shown, comprising a steam-water side system and a molten salt side system, both of which are equipped with heat exchangers. The heat exchanger in the steam-water side system includes a preheater, a steam drum, an evaporator, a superheater, and a reheater, each of which is connected to a steam turbine. The steam generator system is suitable for situations where the target unit capacity of the solar thermal power station is increased and the increased unit cannot directly use a heat exchanger of standard capacity. There are N standard-capacity preheaters, evaporators, superheaters, and reheaters, respectively, which are connected in parallel with each other, where N is a positive integer greater than 1 and N = the increased target unit capacity / standard unit capacity. Taking the increase in unit capacity to 100MW as an example, two 50MW steam generator heat exchanger devices can be connected in parallel, and the steam-water side connecting pipes of the N parallel heat exchangers are of equal length and diameter. This configuration automatically and evenly distributes the heat exchange medium flow, without the need for regulating valves or flow valves for distribution.

[0013] Based on the above, the specific connection method of the heat exchanger is as follows: the feedwater is first connected to the feedwater inlet of the parallel preheater, the feedwater outlet of the parallel preheater is connected to the first inlet of the steam drum, the first outlet of the steam drum is connected to the steam-water inlet of the parallel evaporator, the steam-water outlet of the parallel evaporator is connected to the second inlet of the steam drum, the second outlet of the steam drum is connected to the steam inlet of the parallel superheater, the steam outlet of the parallel superheater is connected to the steam turbine, the exhaust port of the steam turbine is connected to the steam inlet of the parallel reheater, and the steam outlet of the parallel reheater is connected to the steam turbine. This scheme uses a single steam drum for the steam-water side. This is because the steam drum is a container with a relatively simple structure. The workload of increasing its capacity is far less than the workload of designing other heat exchangers. At the same time, using a single steam drum ensures uniform steam mixing. Compared with two steam drums in parallel, it reduces the number of key auxiliary equipment such as steam drum water level control and safety valves, thereby reducing the number of failure points.

[0014] like Figure 2 As shown, the heat exchangers on the molten salt side of the system include a superheater, reheater, evaporator, and preheater. The high-temperature molten salt is connected to the molten salt inlets of N superheaters and N reheaters, respectively. The molten salt inlet of each evaporator is connected to the molten salt outlet of one superheater and one reheater, and the molten salt outlet of each evaporator is connected to the molten salt inlet of one preheater. To reduce the use of valves, the molten salt-side connecting pipes between the N evaporators and the preheater are of equal length and diameter.

[0015] To mitigate the risks of large-capacity systems, a foreign 100MW tower solar thermal unit steam generator system uses a dual-row steam generator system with a 50MW capacity. This requires each steam generator row to be equipped with a corresponding auxiliary system and an isolation valve between the two rows. This solution, however, builds on this foundation by designing a single steam generator system. No isolation valves are installed between parallel heat exchangers with the same function, simplifying the system.

[0016] When the system is running, combined with Figure 1 , the feed water enters the two preheaters through two branches respectively, and the water at the outlet of the preheater merges into one path and enters the steam drum. The working medium in the steam drum enters the two evaporators through the downcomer, and after the phase change occurs in the evaporator, it returns to the steam drum through the riser. Here the height of the steam drum is higher than the height of the evaporator, so that the liquid working medium automatically enters the evaporator by gravity, and the gaseous working medium automatically rises and enters the steam drum, thereby eliminating the use of the boiler water circulation pump. At the same time, the density difference between steam and water in the heat exchange tube can be used to promote the flow of steam and water to form a cycle. The saturated steam separated in the steam drum is divided into two branches and enters the two superheaters. After being heated to superheated steam, it merges into one main steam pipe and enters the steam turbine to do work. The cold reheated steam formed by the exhaust of the high-pressure cylinder of the steam turbine is divided into two branches and enters the two reheaters. The hot reheated steam after being heated again merges into one path and enters the low-pressure cylinder of the steam turbine to continue to do work. Combined with Figure 2 The high-temperature molten salt enters the two superheaters through two branch pipes and the two reheaters through another two branch pipes. The molten salt at the superheater and reheater outlets enters the evaporator and preheater through two branch pipes respectively, and finally merges into a low-temperature molten salt main pipe.

[0017] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by anyone familiar with the art within the technical scope disclosed by the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A multi-heat exchanger parallel integrated steam generator system for a solar thermal power station, comprising a steam-water side system and a molten salt side system, wherein the steam-water side system and the molten salt side system are equipped with heat exchangers, wherein the heat exchangers of the steam-water side system include a preheater, a steam drum, an evaporator, a superheater, and a reheater, wherein the reheater and the superheater are respectively connected to a steam turbine, characterized in that: It is applicable to the case where the target unit capacity of a solar thermal power station is increased and the unit with the increased capacity cannot directly use a heat exchanger of standard capacity. The preheater, the evaporator, the superheater and the reheater of standard capacity are respectively provided with N units and are connected in parallel with each other, N is a positive integer greater than 1, and N=the increased target unit capacity / the standard unit capacity, and the lengths and diameters of the steam-water side connecting pipes of the N parallel heat exchangers are equal.

2. The multi-heat exchanger parallel integrated steam generator system of a CSP plant according to claim 1, characterized in that: The feed water is connected to the feed water inlet of the preheater in parallel, the feed water outlet of the preheater in parallel is connected to the inlet 1 of the steam drum, the outlet 1 of the steam drum is connected to the steam-water inlet of the evaporator in parallel, the steam-water outlet of the evaporator in parallel is connected to the inlet 2 of the steam drum, the outlet 2 of the steam drum is connected to the steam inlet of the superheater in parallel, the steam outlet of the superheater in parallel is connected to the steam turbine, the exhaust port of the steam turbine is connected to the steam inlet of the reheater in parallel, and the steam outlet of the reheater in parallel is connected to the steam turbine.

3. The multi-heat exchanger parallel integrated steam generator system of a CSP plant according to claim 2, characterized in that: The height of the steam drum is higher than that of the evaporator.

4. A multi-heat exchanger parallel integrated steam generator system for a solar thermal power station according to any one of claims 1 to 3, characterized in that: The heat exchanger of the molten salt side system includes the superheater, the reheater, the evaporator and the preheater; the high-temperature molten salt is respectively connected to the molten salt inlets of N superheaters and the molten salt inlets of N reheaters, the molten salt inlet of each evaporator is connected to the molten salt outlet of one of the superheaters and the molten salt outlet of one of the reheaters, and the molten salt outlet of each evaporator is connected to the molten salt inlet of one of the preheaters.

5. The multi-heat exchanger parallel integrated steam generator system of a CSP plant according to claim 4, characterized in that: The lengths and diameters of the molten salt side connecting pipes between the N evaporators and the preheaters are equal.

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