CN107228348B

CN107228348B - Remove tube sheet formula's fused salt steam generator

Info

Publication number: CN107228348B
Application number: CN201710448709.1A
Authority: CN
Inventors: 姚飞奇; 应仁丽; 徐昂; 刘可亮
Original assignee: Hangzhou Boiler Group Co Ltd
Current assignee: Xizi clean energy equipment manufacturing Co.,Ltd.
Priority date: 2017-06-14
Filing date: 2017-06-14
Publication date: 2020-10-23
Anticipated expiration: 2037-06-14
Also published as: CN107228348A

Abstract

The invention discloses a movable tube plate type fused salt steam generating device which comprises a steam drum, a fused salt evaporator, a downcomer, an ascending tube, a fused salt inlet, a fused salt outlet, a water supply inlet and a steam outlet; the molten salt evaporator comprises a cylinder body, an upper end enclosure, a lower end enclosure, an evaporation tube bundle, an upper tube plate, a lower tube plate, a baffle plate, a central cylinder and an inner envelope, wherein a steam pocket is arranged at the upper part of the molten salt evaporator and is connected with the molten salt evaporator through a down pipe and an up pipe; an upper tube plate and a lower tube plate in the molten salt evaporator are arranged up and down, and an evaporation tube bundle is connected with the upper tube plate and the lower tube plate into a whole in a welding or expansion joint mode; an inner cladding is arranged on the outer side of the lower tube plate, a central barrel is arranged in the center of the fused salt evaporator, and a downcomer led out from a steam drum enters the lower part of the fused salt evaporator through the central barrel. The invention effectively solves the problems of high temperature difference and large stress of the single-tube plate and U-shaped tube bundle evaporator, improves the safety of the fused salt evaporator and can reduce the stress born by the evaporation tube bundle.

Description

Remove tube sheet formula's fused salt steam generator

Technical Field

The invention belongs to the technical field of renewable energy utilization, and particularly relates to a movable tube plate type molten salt steam generating device.

Background

Solar energy and wind energy are important components of renewable energy, and in recent years, in order to solve the problem of environmental pollution and reduce fossil energy consumption, renewable energy substitution with solar energy and wind energy as the core is emerging in various countries in the world. China is a country with abundant solar energy resources and wind energy resources, and solar energy and wind energy utilization has been developed in China for nearly ten years. Statistics show that by the end of 2016, the photovoltaic accumulated installed capacity of China is 7800 million and the wind power accumulated installed capacity is 1.49 million and million. The proportion of wind energy and solar energy in energy structures in China is gradually increased.

Because there is no energy storage device with large capacity, the power generation power of wind energy and solar energy is greatly influenced by wind and light resources, so that along with the rapid increase of installed capacity of wind power and photovoltaic power in recent two years, serious wind and light abandoning phenomena exist in the three north areas and the northwest areas where wind power resources are concentrated in China, and the serious local wind and light abandoning rate is close to 30%. In order to solve the problems, a certain fused salt energy storage system must be configured for photovoltaic and wind power, a battery energy storage scheme is generally adopted at present, the service life of a storage battery is usually only 3-5 years, and meanwhile, the recovery treatment of waste batteries is still a problem to be solved. Perhaps beneficial to the fused salt energy storage technology, is an effective method for solving the problems of wind abandonment and light abandonment.

In the technical route of solar power generation, besides photovoltaic power generation, in recent years, photothermal power generation technology is gradually developed from demonstration application to scale application. The solar-thermal power generation generally has a large-scale energy storage system, the collection of sunlight and the process of thermal power generation can be decoupled, power generation is carried out according to the requirements of a power grid, when the proportion of renewable energy sources in a power supply structure is gradually increased, the requirement of the power grid on the schedulability of the power supply can be gradually increased, and the characteristic of the solar-thermal power generation determines to occupy an important position in the future energy structure of China. The heat storage medium adopted by photo-thermal power generation at present is usually molten salt, and the molten salt has the characteristics of high heat capacity, wide liquid phase temperature range, good flowing heat transfer characteristic and the like, and is an ideal heat storage carrier.

When solar resources exist, the generated high-temperature molten salt is stored in the molten salt tank. When a load is required, hot melt salt is extracted to enter a steam generation system, steam with required parameters is generated, and the steam is conveyed to a steam power system to do work and generate power. The molten salt evaporator is an important device of the steam generation system, and the reliability of the molten salt evaporator influences the normal operation of the steam generation system and even the whole generator set. Because the inlet and outlet fused salts of the fused salt evaporator have large temperature difference (possibly exceeding 100 ℃), the traditional U-shaped tube bundle and shell-and-tube heat exchanger structure is adopted, the tube plate of the heat exchanger has high temperature difference and thermal stress, the conditions of cracks and tube opening leakage are easily caused, and the reliability of the fused salt heat exchanger is influenced.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the movable tube plate type fused salt steam generating device is provided, an evaporator adopts a vertically arranged double-tube plate structure, the flow of water and steam is on the tube side, and the flow of fused salt is on the shell side; the double tube plates are respectively arranged at the upper part and the lower part of the evaporator, and two ends of the evaporator tube bundle are respectively connected with the upper tube plate and the lower tube plate through welding or expansion joint; the upper tube plate is fixed with the evaporator cylinder (usually welded), and the lower tube plate can freely expand along the height direction; and a baffle plate is designed on the outer side of the evaporation tube bundle and is used for forming a channel for molten salt to flow.

The technical scheme adopted by the invention for solving the technical problems is as follows: a movable tube plate type fused salt steam generating device comprises a steam drum, a fused salt evaporator, a downcomer, an ascending tube, a fused salt inlet, a fused salt outlet, a water supply inlet and a steam outlet; the molten salt evaporator comprises a cylinder body, an upper end enclosure, a lower end enclosure, an evaporation tube bundle, an upper tube plate, a lower tube plate, a baffle plate, a central cylinder and an inner envelope, wherein a steam pocket is arranged at the upper part of the molten salt evaporator and is connected with the molten salt evaporator through a down pipe and an up pipe; an upper tube plate and a lower tube plate in the molten salt evaporator are arranged up and down, and an evaporation tube bundle is connected with the upper tube plate and the lower tube plate into a whole in a welding or expansion joint mode; an inner cladding is arranged on the outer side of the lower tube plate, a central barrel is arranged in the center of the fused salt evaporator, and a downcomer led out from a steam drum enters the lower part of the fused salt evaporator through the central barrel.

During normal work, feed water enters the steam pocket through the water supply pipe, saturated water in the steam pocket enters the molten salt evaporator through the downcomer, the downcomer enters the lower portion of the molten salt evaporator through the central cylinder, the saturated water enters the evaporation tube bundle in the inner cladding changing direction, heat is absorbed in the evaporation tube bundle to complete the gasification evaporation process, the saturated water enters the steam pocket through the steam water ascending tube, steam-water separation is completed in the steam pocket, the separated steam flows out of the molten salt steam generating device from the steam outlet, the saturated water and the water in the steam pocket are mixed and enter the downcomer again, the baffle plate is arranged on the outer side of the evaporation tube bundle, molten salt flows through the flowing formed by the baffle plate, heat is transferred to media in the tube, and the gasification evaporation process of the whole water is completed.

Compared with the prior art, the invention has the advantages that:

(1) the double-tube plate evaporator structure arranged up and down effectively solves the problems of high temperature difference and large stress of a single-tube plate and U-shaped tube bundle evaporator, and improves the safety of the fused salt evaporator;

(2) the movable lower tube plate structure can effectively absorb the expansion displacement difference of the evaporation tube bundle under the conditions of starting, stopping and variable working conditions, and reduce the stress borne by the evaporation tube bundle;

(3) according to the invention, water and steam flow from the pipe side to the pipe side, and the flow direction is from bottom to top (vertical arrangement is adopted), so that the design scheme is beneficial to the power circulation of water and steam; the system can adopt a natural circulation mode, so that the initial investment can be reduced and the operating cost can be saved;

(4) the arrangement scheme of the molten salt flow on the shell side is beneficial to salt dredging and condensation preventing of the evaporator, and the safety of the molten salt evaporation system can be improved.

Drawings

FIG. 1 is a schematic diagram of the working principle of the movable tube plate type molten salt steam generating device.

The reference numbers in the figures mean: the device comprises a steam drum 1, a molten salt evaporator 2, a downcomer 3, an upcomer 4, a molten salt inlet 5, a molten salt outlet 6, a water supply inlet 7, a steam outlet 8, a cylinder 21, an upper end enclosure 22, a lower end enclosure 23, an evaporation tube bundle 24, an upper tube plate 25, a lower tube plate 26, a baffle plate 27, a central cylinder 28 and an inner cladding 29.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in fig. 1, the present invention provides a moving tube sheet type molten salt steam generator, comprising: the system comprises a steam drum 1, a molten salt evaporator 2, a downcomer 3, an ascending pipe 4, a molten salt inlet 5, a molten salt outlet 6, a feed water inlet 7 and a steam outlet 8; the molten salt evaporator 2 includes: barrel 21, upper head 22, lower head 23, evaporator tube bundle 24, upper tube plate 25, lower tube plate 26, baffle 27, central tube 28 and inner shell 29.

The steam drum 1 is arranged above the molten salt evaporator 2, and the molten salt evaporator 2 is arranged vertically and is connected with the steam drum 1 into a whole through a downcomer 3 and an upcomer 4. The shell of the fused salt evaporator 2 consists of a cylinder 21, an upper seal head 22 and a lower seal head 23; the evaporator internal member mainly comprises an evaporator tube bundle 24, an upper tube plate 25, a lower tube plate 26 and a baffle plate 27, wherein the upper tube plate 25 is tightly connected with the cylinder body (generally in a welding mode), and the lower tube plate 26 can freely expand along the axial direction in the evaporator cylinder body 21. The centers of the upper tube plate 25, the lower tube plate 26 and the evaporator tube bundle 24 are provided with a central tube 28, and the merged down tubes 3 enter the lower part of the evaporator through the central tube 28. Baffle plates 27 are arranged on the outer side of the evaporation tube bundle 24 at intervals in the direction vertical to the tubes, hot-melt salt entering from the molten salt inlet 5 passes through a flow channel formed by the baffle plates 27, heat is transferred to working media in the evaporation tube bundle 24, and the hot-melt salt flows out of the evaporator from the molten salt outlet 6 after the temperature is reduced. The outer side of the lower tube plate 26 is provided with an inner cladding 29, saturated water from the downcomer 3 flows through the lower tube plate 26, the evaporator tube bundle 24 and the upper tube plate 25 in sequence under the pushing of gravity pressure difference after being baffled reversely by the inner cladding (29), and the vaporization and evaporation processes of part of water are completed in the evaporator tube bundle 24. Two-phase flow enters the steam pocket 1 through the ascending pipe 4, the steam-water separation process is completed in the steam pocket 1, saturated steam flows out of the evaporation system through the steam outlet 8, the water supplemented by the steam pocket enters the steam pocket through the water supply pipe 7 so as to maintain the water level of the steam pocket 1 at a normal position, and the saturated water reenters the evaporator 2 through the descending pipe 3, so that the circulation process of the evaporation system is completed.

A movable tube plate type fused salt steam generating device is characterized in that the lower tube plate 26 can be movably designed to effectively absorb the expansion difference of an evaporation tube bundle 24 in a cold and hot state; meanwhile, the double-tube-plate design scheme can eliminate the temperature difference and stress existing on the U-shaped tube and the single-tube plate structure. The vertical arrangement of the fused salt evaporator 2 is beneficial to the establishment of natural circulation, and the circulating pump and the operating cost are saved; meanwhile, the arrangement mode of the molten salt flow on the shell side is also favorable for salt dredging, and the safety of the system is improved.

With the gradual recognition of the heat storage capacity of the molten salt, the application of the molten salt in the field of energy storage becomes wider and wider, and the molten salt evaporation system has a wide application prospect.

Claims

1. The utility model provides a remove tube sheet formula's fused salt steam generator which characterized in that: the evaporator adopts a vertically-arranged double-pipe plate structure, the water and steam flow is on the pipe side, and the molten salt flow is on the shell side; the double tube plates are respectively arranged at the upper part and the lower part of the evaporator, and two ends of the evaporator tube bundle are respectively connected with the upper tube plate and the lower tube plate through welding or expansion joint; the upper tube plate is fixed with the evaporator cylinder, and the lower tube plate can freely expand along the height direction; the outer side of the evaporation tube bundle is provided with a baffle plate for forming a molten salt flowing channel, and the baffle plate comprises a steam drum (1), a molten salt evaporator (2), a downcomer (3), an ascending tube (4), a molten salt inlet (5), a molten salt outlet (6), a water supply inlet (7) and a steam outlet (8); the molten salt evaporator (2) comprises a cylinder (21), an upper seal head (22), a lower seal head (23), an evaporator tube bundle (24), an upper tube plate (25), a lower tube plate (26), a baffle plate (27), a central cylinder (28) and an inner wrapping shell (29), wherein a steam drum (1) is arranged at the upper part of the molten salt evaporator (2) and is connected with the molten salt evaporator (2) through a downcomer (3) and an upcomer (4); an upper tube plate (25) and a lower tube plate (26) in the molten salt evaporator (2) are arranged up and down, and an evaporator tube bundle (24) is connected with the upper tube plate (25) and the lower tube plate into a whole in a welding or expansion joint mode; an inner cladding (29) is arranged on the outer side of the lower tube plate (26), a central barrel (28) is arranged in the center of the molten salt evaporator (2), and a downcomer (3) led out from the steam drum (1) enters the lower part of the molten salt evaporator (2) through the central barrel (28);

during normal work, feed water enters the steam pocket (1) through the water supply pipe, saturated water in the steam pocket (1) enters the molten salt evaporator (2) through the downcomer (3), the downcomer (3) enters the lower part of the molten salt evaporator (2) through the central cylinder (28), the saturated water enters the evaporation tube bundle (24) through the inner cladding (29) in a changed direction, heat is absorbed in the evaporation tube bundle (24) to complete a gasification evaporation process, the saturated water enters the steam pocket (1) through the steam water riser (4), steam-water separation is completed in the steam pocket (1), the separated steam flows out of the molten salt steam generating device from the steam outlet (8), the saturated water is mixed with the water in the steam pocket (1) and enters the downcomer (3) again, the outer side of the evaporation tube bundle (24) is provided with the baffle plate (27), molten salt flows through the flow formed by the baffle plate (27) to transfer heat to media in the tube, the gasification and evaporation process of water is completed; wherein the content of the first and second substances,

the steam drum (1) is arranged above the molten salt evaporator (2), the molten salt evaporator (2) is arranged vertically and is connected with the steam drum (1) into a whole through a downcomer (3) and an ascending pipe (4), and the shell of the molten salt evaporator (2) consists of a cylinder body (21), an upper end enclosure (22) and a lower end enclosure (23); the evaporator comprises an evaporator tube bundle (24), an upper tube plate (25), a lower tube plate (26) and a baffle plate (27), wherein the upper tube plate (25) is tightly connected with a cylinder body, the lower tube plate (26) can freely expand along the axial direction in the evaporator cylinder body (21), the centers of the upper tube plate (25), the lower tube plate (26) and the evaporator tube bundle (24) are provided with a central tube (28), a converged downcomer (3) enters the lower part of the evaporator through the central tube (28), the outer side of the evaporator tube bundle (24) is provided with the baffle plate (27) at intervals in the direction vertical to the tubes, hot melt salt entering from a molten salt inlet (5) passes through a flow channel formed by the baffle plate (27) to transfer heat to a working medium in the evaporator tube bundle (24), the hot melt salt flows out of the evaporator from a molten salt outlet (6) after the temperature is reduced, the outer side of the lower tube plate (26) is provided with an inner cladding (29), the steam enters the steam drum (1) through the ascending pipe (4) to complete the steam-water separation process in the steam drum (1), the saturated steam flows out of the evaporation system from the steam outlet (8), the steam drum water supplement enters the steam drum through the water supply inlet (7) to maintain the water level of the steam drum (1) at a normal position, and the saturated water reenters the evaporator (2) through the descending pipe (3) to complete the circulation process of the evaporation system.