A steam drum water supply system of a solid electric heat accumulating steam boiler

Abstract

This invention discloses a steam drum makeup water system for a solid-state electric thermal storage steam boiler, relating to the field of solid-state electric thermal storage technology. Its features include: each steam drum is connected to a makeup water flow control component and a makeup water circulation component; the makeup water circulation component connects each steam drum to a feedwater tank via a steam output main pipe, a feedwater main pipe, and an overflow main pipe; the makeup water flow control component consists of a temperature-controlled flow valve, a water temperature sampler, a temperature compensator, and a temperature-controlled conduit. The purpose of this invention is to solve the problems of high system failure rate, complex control, and increased maintenance costs when multiple steam drums are installed in parallel within a solid-state electric thermal storage steam boiler. The technical advantages of this invention are that multiple steam drums share a single makeup water system, enabling stable operation of each steam drum; the system control is simple; the equipment footprint is small, saving equipment investment; and the utilization rate of thermal energy is improved.

Description

Technical Field

[0001] This invention relates to the field of solid-state electric thermal energy storage technology, specifically to a solid-state electric thermal energy storage steam boiler that operates at a voltage of 10kV to 110kV, in which multiple steam drums are installed in parallel, and the multiple steam drums share a single water supply system, which can achieve stable operation of each steam drum. Background Technology

[0002] Steam heat sources commonly used in industrial production processes are coal-fired or gas-fired boilers with a capacity of over 20 tons per hour. In some industries, the steam output from these boilers often exceeds 100 tons per hour. If solid-state electric thermal storage (SEPS) steam boilers were to replace coal-fired or gas-fired boilers, multiple boilers would need to operate in parallel to achieve an industrial steam output capacity of several hundred tons per hour. Existing SEPS steam boilers typically have at least one steam drum, with each drum producing less than 10 tons of steam. Each steam drum requires an independent water supply system. When multiple SEPS steam boilers operate in parallel, the combined steam output parameters must meet the requirements of the industrial production process, and the steam output must synchronously follow changes in steam consumption. Each steam drum must have an independent water level detection device and control system to accurately and reliably adjust the water supply pumps or valves of each steam drum's independent water supply system. However, when the number of steam drums in this configuration is more than three, more than three sets of water replenishment systems need to be installed. This configuration increases the failure rate, increases the complexity of controlling the solid electric thermal storage steam boiler, and increases the maintenance cost of the equipment in the later stage. Summary of the Invention

[0003] In view of the above technical requirements, the present invention provides a steam drum water supply system for a solid electric thermal storage steam boiler, which aims to solve the problems of high system failure rate, complex control and increased maintenance costs when multiple steam drums are installed in parallel in a solid electric thermal storage steam boiler.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A steam drum water supply system for a solid-state electric thermal storage steam boiler includes multiple heat exchanger groups connected in parallel with multiple steam drums, and multiple steam drums connected to a feedwater tank via multiple pipelines. The system is characterized in that each steam drum is connected to a corresponding water supply flow control component and a water supply circulation component; the water supply circulation component connects each steam drum to the feedwater tank via a steam output main pipe, a feedwater main pipe, and an overflow main pipe. The water supply flow control component consists of a temperature-controlled flow valve, a water temperature sampler, a temperature compensator, and a temperature-controlled conduit. A steam drum water supply pipe is connected to the bottom of the steam drum, and a temperature-controlled flow valve is installed on the steam drum water supply pipe. The steam drum water supply pipe is connected to the main water supply pipe. The temperature-controlled flow valve is connected to a water temperature sampler through a temperature-controlled conduit. The water temperature sampler is a sealed container filled with a temperature-sensitive expansion liquid, which can withstand the internal liquid pressure following the temperature change of the overflow pipe.

[0005] In the water replenishment flow control component, an overflow pipe is installed inside the steam drum. The upper port of the overflow pipe is set at the same height as the evaporation liquid level inside the steam drum, and the lower port is connected to the steam drum overflow water temperature sampler.

[0006] The water replenishment and circulation assembly consists of a water replenishment pump, a water tank level gauge, a steam arrestor, a circulation pump, and a temperature probe installed on the water supply tank connected to the steam output main pipe. The water replenishment pump is installed on the pipeline connecting the water supply tank to the external water source. The circulation pump is installed on the pipeline connecting the water supply tank to the main water supply pipe. The steam arrestor is installed on the pipeline connecting the water supply tank to the overflow main pipe.

[0007] The steam arrester is a sealed metal container with a steam arrester inlet at the bottom connected to the overflow manifold and a steam arrester outlet at the top connected to the feedwater tank.

[0008] The temperature compensator is a metal component connected to the water temperature sampler whose heat dissipation does not change with the ambient temperature.

[0009] There are 3 to 60 steam drums connected in parallel to the steam output main pipe at the inlet end of the steam meter.

[0010] Thermosensitive expansion liquid is placed in a sealed container. It is a liquid that can absorb the heat energy released by the overflow pipe and convert it into expansion force, which can drive the temperature-controlled flow valve to complete the alternating opening and closing process.

[0011] The aforementioned temperature-controlled flow valve is a hydraulic control valve capable of withstanding saturated water temperature and pressure.

[0012] The heat exchanger group consists of 1 to 10 shell-and-tube heat exchangers connected to the same steam drum. The shell-and-tube heat exchangers are made of welded metal finned tubes.

[0013] Steam meters are electromagnetic, orifice plate, or vortex street type heat energy metering instruments with steam parameter acquisition and remote transmission functions.

[0014] The technical solution adopted in this invention has the following advantages: When solid-state electric thermal storage (SEPFS) steam boilers replace coal-fired or gas-fired steam boiler systems, the output capacity of hundreds of tons of industrial steam is achieved by operating multiple units in parallel. This requires each SEPFS steam drum to output steam with identical parameters. To synchronize with changes in production steam demand, each steam drum needs an independent water supply system, resulting in a complex system structure. The technical solution of this invention involves installing multiple steam drums in parallel within the SEPFS steam boiler, with all steam drums sharing a single water supply system. This ensures stable operation of each steam drum, simplifies system control, reduces equipment footprint and investment costs, and improves the utilization rate of thermal energy. Attached Figure Description

[0015] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein: Figure 1 This is a schematic diagram of the system configuration of the present invention; Figure 2 This is a schematic diagram of the water replenishment flow control component of the present invention.

[0016] Explanation of icon numbers: 1. Steam drum; 2. Heat exchanger assembly; 3. Riser pipe; 4. Steam drum feedwater pipe; 5. Overflow pipe; 6. Downcomer pipe; 7. Steam output main pipe; 8. Feedwater main pipe; 9. Overflow main pipe; 10. Circulating water pump; 11. Feedwater tank; 12. Makeup water pump; 13. Water tank level gauge; 14. Steam arrester; 14-1. Steam arrester inlet; 14-2. Steam arrester outlet; 15. Temperature-controlled flow valve; 16. Water temperature sampler; 17. Temperature-controlled conduit; 18. Temperature probe; 19. Steam meter; 20. Temperature compensator; 21. Makeup water flow control assembly; 22. Evaporation liquid level; 23. Makeup water circulation assembly; 24. Upper port; 25. Expansion liquid. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Unless otherwise specified, the techniques used in the embodiments are conventional means well known to those skilled in the art.

[0018] Example: In this example, Figure 1 This is a schematic diagram of the system configuration of the present invention. Figure 2This is a schematic diagram of the water replenishment flow control component of the present invention, combined with... Figure 1 , Figure 2The following is an explanation. In this embodiment, a steam drum makeup water system for a solid electric thermal storage steam boiler includes 3 to 60 steam drums 1 connected in parallel to the steam output main pipe 7 at the inlet end of the steam meter 19, a heat exchanger group 2 and a makeup water flow control component 21 connected to each steam drum 1, and a makeup water circulation component 23 connected to the steam output main pipe 7, the feed water main pipe 8 and the overflow main pipe 9. The piping in heat exchanger group 2 is connected to the solid thermal storage boiler; the makeup water circulation assembly 23 consists of a makeup water pump 12, a water tank level gauge 13, a steam arrester 14, a circulation pump 10, and a temperature probe 18 installed on the feedwater tank 11 connected to the steam output main pipe 7; the makeup water flow control assembly 21 consists of a temperature control flow valve 15, a water temperature sampler 16, a temperature compensator 20, and a temperature control conduit 17; an overflow pipe 5 is installed inside the steam drum 1, with the upper port 24 of the overflow pipe 5 set at the same height as the evaporation liquid level 22 inside the steam drum 1, and the lower port connected to the steam drum overflow water temperature sampler 16; the steam arrester 14 has a steam arrester inlet 14-1 connected to the overflow main pipe 9 at the bottom and a steam arrester outlet 14-2 connected to the feedwater tank 11 at the top. The water temperature sampler 16 is connected to the temperature control conduit 17 and is a sealed metal container filled with temperature-sensitive expansion liquid 25. It can withstand the internal liquid pressure following the temperature change of the overflow pipe 5. The temperature control conduit 17 is a metal conduit filled with temperature-sensitive expansion liquid 25, located between the water temperature sampler 16 and the temperature control flow valve 15. It can transmit the expansion force of the temperature-sensitive expansion liquid 25 in the water temperature sampler 16 and drive the temperature control flow valve 15 to be in the open or closed state. The temperature compensator 20 is connected to the water temperature sampler 16. Its compensation mechanism only compensates for the temperature change of the water temperature sampler 16. The heat dissipation of the temperature compensator 20 does not change with the ambient temperature. The temperature control flow valve 15 is a hydraulic control valve that can withstand the pressure of saturated water temperature. The steam meter 19 is an electromagnetic, orifice plate, or vortex type heat energy metering instrument with steam parameter acquisition and remote transmission functions; the heat exchanger group 2 consists of 1 to 10 shell-and-tube heat exchangers connected to the same steam drum 1, with the shell-and-tube heat exchangers being welded from metal finned tubes; the circulating pump 10 and the makeup water pump 12 are high-temperature resistant water pumps capable of withstanding the working temperature and pressure of saturated water. Thermosensitive expansion liquid 25 is a liquid placed in the sealed container of the water temperature sampler 16, capable of absorbing the heat energy of the saturated water flowing out of the overflow pipe 5 connected to the water temperature sampler 16, causing a volume change, and generating an axial force to drive the temperature control flow valve 15 to complete the alternating opening and closing process. Thermosensitive expansion liquid 25 is a mixture of water and ethylene glycol, ethers, heat transfer oil, etc., liquids whose volume energy changes accordingly with temperature. Its volume-temperature change curve is suitable for the working temperature conditions of this system. If a mixture of water and ethylene glycol is used, the appropriate mixing ratio of water and ethylene glycol can be selected according to the sampling temperature range of the water temperature sampler 16.

[0019] Water supply flow control process: When the steam drum 1 of the solid-state electric thermal storage steam boiler has steam output, it needs to be replenished with water. The circulating water driven by the circulating pump 10 is sent into the steam drum 1 through the temperature-controlled flow valve 15. When the replenishment water in the steam drum 1 reaches the evaporation surface, the saturated water overflows from the upper port 24 of the overflow pipe 5. The heat energy released by the overflowing saturated water flowing through the overflow pipe 5 is continuously absorbed by the temperature-sensitive expansion liquid 25 in the container of the water temperature sampler 16, causing the temperature-sensitive expansion liquid 25 in the container to gradually heat up and generate a continuously increasing expansion force. The expansion force is transmitted to the temperature-controlled flow valve 15 through the temperature-controlled conduit 17 connected to the container of the water temperature sampler 16, compressing the built-in spring of the temperature-controlled flow valve 15, thereby driving the valve core to gradually reduce the flow of the temperature-controlled flow valve 15 until the temperature-controlled flow valve 15 is closed. The temperature-controlled flow valve 15 in the closed state causes the overflow pipe With no circulating water overflowing from the overflow pipe 5, the temperature-sensitive expansion liquid 25 in the water temperature sampler 16 loses its heating from the overflow pipe 5 and enters a cooling state. As the temperature decreases, the expansion force of the temperature-sensitive expansion liquid 25 continuously weakens, and this weakening thrust is transmitted to the temperature-controlled flow valve 15 via the temperature control conduit 17. The built-in spring of the temperature-controlled flow valve 15 gradually recovers, thereby driving the valve core to gradually open the flow rate of the steam drum 1 to replenish water until the temperature-controlled flow valve 15 is fully open. The reciprocating water replenishment cycle of the steam drum 1 is a necessary condition for the stable steam output of this system. Adjusting the heat dissipation of the matching temperature compensator 20 can optimize the heating and cooling rate of the temperature-sensitive expansion liquid 25 in the water temperature sampler 16, which can affect the working state of the temperature-controlled flow valve 15 and achieve the effect of stabilizing the water replenishment flow curve of the steam drum 1. In summary, the temperature-sensitive expansion liquid 25 utilizes the changes in expansion force caused by the temperature rise when there is saturated water flowing out of the overflow pipe 5 and the temperature drop when there is no saturated water flowing out, to complete the working process of closing and opening the temperature control flow valve 15 in a cycle, thereby realizing the dynamic automatic balance water replenishment process of each steam drum 1.

[0020] Working process of solid-state electric thermal storage steam boiler: like Figure 1As shown, before the system enters the working state, the water replenishment pump 12 is started to inject deoxygenated water into the feedwater tank 11. The water level in the feedwater tank 11 is brought to the control water level line, approximately 2 / 3 of the height inside the tank. The water replenishment pump 12 then stops replenishing water, and automatic control is established to maintain this water level. If the water level falls below this line, water is automatically replenished. Once the water level reaches the control line, the circulation pump 10 is started to inject the deoxygenated water from the feedwater tank 11 into each steam drum 1. During the replenishment process for each steam drum 1, the water replenishment pump 12 continuously replenishes water into the feedwater tank 11 to keep the water level line at approximately 2 / 3 of the height inside the tank stable. When the water replenishment pump 12 stops replenishing water, and the water level line in the feedwater tank 11 remains stable, it indicates that water is overflowing from the upper port 24 of the overflow pipe 5 in each steam drum 1. The circulating water driven by the circulation pump 10 has reached equilibrium, and the replenishment work for each steam drum 1 has been completed. The circulation pump 10 can then be stopped. At this point, the solid-state electric thermal storage steam boiler has met the normal start-up conditions. The solid-state electric thermal storage steam boiler is connected to the power supply to carry out thermal storage work. When the solid thermal storage temperature reaches the output steam requirement, the heat exchanger group 2 is started to heat the deoxygenated water in the steam drum 1 to produce steam. The steam output from each steam drum 1 is collected into the steam output main pipe 7 and output to the heat user through the steam meter 19. When steam is output from the steam output main 7, start the circulating pump 10, making the output flow rate of the circulating pump 10 greater than 1 / 10 to 1 / 20 of the flow rate measured by the steam meter 19, and read the temperature value of the temperature probe 18 in real time. Under the condition that the water supply pump 12 continuously and normally supplies water, the water temperature in the feedwater tank 11 measured by the temperature probe 18 is 15°C lower than the temperature of the saturated water in the steam drum 1. If it is not lower than 15°C, the flow rate of the circulating pump 10 can be adjusted to be greater than 1 / 10 to 1 / 20 of the flow rate measured by the steam meter 19, or the water supply of the water supply pump 12 can be appropriately increased within the controllable range of the water level in the feedwater tank 11. The purpose is to reduce the risk of cavitation of the circulating pump 10, ensure the stable operation of the circulating pump 10, and extend the service life of the circulating pump 10.

[0021] This system can also send the output saturated steam through a steam-water separator to reduce the water content in the saturated steam before sending it to the superheater heat exchanger for reheating, thus providing superheated steam to users who need it.

[0022] The water replenishment system of the present invention mainly solves the problems of existing technologies where multiple (three or more) steam drums 1 need to be equipped with separate water supply regulation systems for independent control when connected in parallel, which is prone to failure and also brings problems such as difficult control coordination and high maintenance costs.

[0023] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in 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 determined by the scope of the claims.

Claims

1. A steam drum makeup water system for a solid-state electric thermal storage steam boiler, comprising multiple heat exchanger groups (2) connected in parallel with multiple steam drums (1), and multiple steam drums (1) connected to a feedwater tank (11) via multiple pipelines, characterized in that: Each steam drum (1) is connected to a water supply flow control component (21) and a water supply circulation component (23); the water supply circulation component (23) is connected to the water supply tank (11) through the steam output main pipe (7), the water supply main pipe (8), and the overflow main pipe (9) of each steam drum (1); The water supply flow control component (21) consists of a temperature control flow valve (15), a water temperature sampler (16), a temperature compensator (20), and a temperature control conduit (17). A steam drum water supply pipe (4) is connected to the bottom of the steam drum (1), and a temperature control flow valve (15) is installed on the steam drum water supply pipe (4). The steam drum water supply pipe (4) is connected to the main water supply pipe (8). The temperature control flow valve (15) is connected to a water temperature sampler (16) through a temperature control conduit (17). The water temperature sampler (16) is a sealed container that is filled with temperature-sensitive expansion liquid (25) and can withstand the internal liquid pressure following the temperature change of the overflow pipe (5).

2. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: In the water replenishment flow control component (21), an overflow pipe (5) is provided inside the steam drum (1). The upper port (24) of the overflow pipe (5) is set at the same height as the evaporation liquid surface (22) inside the steam drum (1), and the lower port is connected to the steam drum overflow water temperature sampler (16).

3. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: The water replenishment circulation assembly (23) consists of a water replenishment pump (12), a water tank level gauge (13), a steam arrester (14), a circulation pump (10), and a temperature probe (18) installed on the water supply tank (11) connected to the steam output main pipe (7). The water replenishment pump (12) is installed on the pipeline connecting the water supply tank (11) to the external water source. The circulation pump (10) is installed on the pipeline connecting the water supply tank (11) to the water supply main pipe (8). The steam arrester (14) is installed on the pipeline connecting the water supply tank (11) to the overflow main pipe (9).

4. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: The steam arrester (14) is a sealed metal container with a steam arrester inlet (14-1) connected to the overflow manifold (9) at the bottom and a steam arrester outlet (14-2) connected to the feedwater tank (11) at the top.

5. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: The temperature compensator (20) is a metal component connected to the water temperature sampler (16) whose heat dissipation does not change with the ambient temperature.

6. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: There are 3 to 60 steam drums (1) connected in parallel to the steam output main pipe (7) at the inlet end of the steam meter (19).

7. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: The temperature-sensitive expansion liquid (25) is placed in a sealed container. It is a liquid that can convert the heat energy released by the overflow pipe (5) into expansion force and drive the temperature-controlled flow valve (15) to complete the alternating opening and closing process.

8. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: The temperature control flow valve (15) is a hydraulic control valve that can withstand the temperature and pressure of saturated water.

9. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 1, characterized in that: The heat exchanger group (2) consists of 1 to 10 shell-and-tube heat exchangers connected to the same steam drum (1), and the shell-and-tube heat exchangers are made of welded metal finned tubes.

10. The steam drum makeup water system of a solid-state electric thermal storage steam boiler according to claim 6, characterized in that: Steam meter (19) is an electromagnetic, orifice plate, or vortex street type heat energy metering instrument with steam parameter acquisition and remote transmission function.

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