Heat storage tank constant-displacement expansion vessel exhaust steam utilization system

Abstract

The utility model discloses a heat storage tank fixed discharge expander steam utilization system, including heat storage tank, fixed discharge expander, steam ejector, pressure reducing valve, shut-off valve, main steam pipeline, heat storage tank blowdown pipeline, low pressure steam pipeline, expander steam pipeline, expander steam exhaust pipeline, expander blowdown pipeline, the main steam pipeline is divided into two branches, one branch is connected to steam ejector, and the other branch is connected to pressure reducing valve, and the two branch pipelines are evenly provided with shut-off valve in the middle, one end of steam ejector is connected with main steam pipeline, and the other end is connected with low pressure steam pipeline, heat storage tank is connected together through the blowdown pipeline of bottom with fixed discharge expander, and the top of fixed discharge expander is equipped with expander steam pipeline, and the expander steam pipeline is equipped with two branches, branch one is connected to steam ejector, and branch two is connected to expander steam exhaust pipeline, the bottom of fixed discharge expander is equipped with blowdown pipeline, and when the water level of fixed discharge expander exceeds the design water level line, the water in fixed discharge expander can be discharged through blowdown pipeline.

Description

Technical Field

[0001] This utility model belongs to the technical field of thermal storage equipment, and relates to a waste steam utilization system for thermal storage tanks with fixed discharge expansion vessels. Background Technology

[0002] In recent years, renewable energy power generation such as wind power and solar power has experienced rapid development. However, due to the significant impact of weather on wind and solar power, their intermittent and unpredictable nature leads to widespread curtailment of wind and solar power, resulting in energy waste. The development of thermal storage technology is of great significance in solving these problems.

[0003] With the gradual maturation of steam thermal storage technology, the application of thermal storage tanks is becoming increasingly widespread. Chinese patent CN115681927A discloses an electric thermal energy storage steam supply system, including an electric heater, a thermal storage spherical tank, a circulating pump set, a steam dryer, and a steam distribution cylinder. After the system operates for a period of time, scale will accumulate inside the thermal storage tank, and the water level will rise. To maintain the safe operation of the thermal storage tank, wastewater must be discharged periodically through a drain outlet. This wastewater discharge process results in heat loss, but the system does not include a waste steam utilization system for a fixed-discharge expansion tank. Chinese patents CN113008064A and CN104048286A also relate to thermal storage technology, but neither includes a waste steam utilization system for a fixed-discharge expansion tank.

[0004] Chinese patent CN10889585B discloses a waste heat recovery system and method for boiler fixed-discharge expansion tanks, mainly used for waste heat recovery from waste steam in fixed-discharge expansion tanks. The waste heat recovery system includes a fixed-discharge expansion tank, a control terminal, a liquid collection and separation tank, a drain valve, a pre-pump valve, a water pump, a post-pump valve, a pump check valve, a primary discharge valve, a steam-side gate valve, a discharge valve, a vent valve, a steam-side check valve, a steam-liquid mixer, a water-side electric regulating valve, a water-side gate valve, a level gauge, and pipelines No. 1, 2, 3, 4, 5, 6, 7, and 8, as well as wires No. 1, 2, 3, and 4. This device can only transfer waste steam heat to cold water; the project must have sufficient cold water to absorb this heat. Some projects do not require hot water, limiting its application scenarios. Furthermore, the system contains energy-consuming equipment such as water pumps, resulting in less than ideal energy utilization efficiency.

[0005] Thermal storage tanks typically supply low-pressure steam to heat users. The operating pressure of the storage tank is higher than the steam pressure used by the users. For example, in a certain project, the steam supply pressure is 0.8 MPa, but to improve the storage capacity of the thermal storage tank, its operating pressure is increased to 2.5 MPa. There is a pressure difference between the heating steam supply tank and the user end. If a steam ejector can be installed to utilize this pressure difference to eject the exhaust steam from the fixed-discharge expansion tank, the recovered exhaust steam can be directly used for heating. Furthermore, the system for utilizing exhaust steam from fixed-discharge expansion tanks is simpler and has a wider range of applications.

[0006] In summary, the waste steam recovery system for fixed-discharge expansion tanks can effectively recover waste steam to achieve energy conservation. However, only by rationally designing the recovery system can the pressure drop of the heat storage tank be effectively utilized to maximize the recovery of waste heat and waste steam, and improve the energy quality of the recovered waste steam. Utility Model Content

[0007] The purpose of this invention is to provide a waste heat utilization system for exhaust steam from a thermal storage tank expansion vessel, which reduces heat loss from exhaust steam and improves the heating capacity of the thermal storage tank while ensuring the quality of water and steam.

[0008] This utility model is achieved through the following technical solution: The thermal storage tank exhaust steam utilization system includes a thermal storage tank, an exhaust steam expansion tank, a pressure reducing valve, a shut-off valve, a main steam pipeline, a thermal storage tank drain pipeline, a low-pressure steam pipeline, an expansion tank exhaust steam pipeline, an expansion tank exhaust steam venting pipeline, and an expansion tank drainage pipeline. The thermal storage tank is connected to the main steam pipeline at the top, and a steam ejector is installed on the main steam pipeline. One end of the steam ejector is connected to the main steam pipeline, and the other end is connected to the low-pressure steam pipeline. The expansion tank exhaust steam pipeline has two branches, one branch is connected to the steam ejector, and the other branch is connected to the expansion tank exhaust steam venting pipeline.

[0009] Furthermore, the main steam pipeline has two branches, one of which connects to the steam ejector and the other to the pressure reducing valve. A shut-off valve is installed in the middle of both branches.

[0010] Furthermore, the heat storage tank is connected to the fixed-discharge expansion container via a drain pipe at the bottom, and the top of the fixed-discharge expansion container is connected to the exhaust steam pipe of the expansion container.

[0011] Working principle: Wastewater from the thermal storage tank enters the fixed-discharge expansion tank through the thermal storage tank drain pipe. Inside the expansion tank, the wastewater flashes and transforms into low-pressure exhaust steam and saturated water. The low-pressure exhaust steam is sent to the steam ejector through the expansion tank exhaust steam pipe. High-pressure steam from the thermal storage tank enters the steam ejector through the main steam pipe. The high-pressure steam flows within the steam ejector, creating an ejection effect that draws in the exhaust steam from the fixed-discharge expansion tank. Within the steam ejector, the pressure of the high-pressure steam decreases, while the pressure of the low-pressure exhaust steam increases. The two mix together and flow out from the steam ejector outlet as low-pressure steam. Unflashed water in the fixed-discharge expansion tank is discharged through the thermal storage tank drain pipe.

[0012] Compared with the prior art, the innovation and beneficial effects of this utility model are as follows: by setting up a steam ejector, the exhaust steam in the constant discharge expansion vessel can be utilized, and the pressure difference of the heat storage tank can be used to improve energy utilization efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0014] In the diagram: 1. Heat storage tank, 2. Fixed discharge expansion tank, 3. Steam ejector, 4. Pressure reducing valve, 5. Shut-off valve, 6. Main steam pipeline, 7. Heat storage tank drain pipeline, 8. Low-pressure steam pipeline, 9. Exhaust steam pipeline of expansion tank, 10. Exhaust steam venting pipeline of expansion tank to the atmosphere, 11. Drainage pipeline of expansion tank. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Figure 1 The diagram shows a thermal storage tank and expansion vessel waste steam utilization system, comprising a thermal storage tank 1, a fixed-discharge expansion vessel 2, a steam ejector 3, a pressure reducing valve 4, a shut-off valve 5, a main steam pipeline 6, a thermal storage tank drain pipeline 7, a low-pressure steam pipeline 8, an expansion vessel waste steam pipeline 9, an expansion vessel waste steam venting pipeline 10, and an expansion vessel drainage pipeline 11. The thermal storage tank 1 is connected to the top of the main steam pipeline 6, which has two branches: one branch connects to the steam ejector 3, and the other branch connects to the pressure reducing valve 4. A shut-off valve 5 is installed in the middle of each branch pipeline. One end of the heat storage tank drain pipe 7 is connected to the bottom of the heat storage tank 1, and the other end is connected to the fixed discharge expansion container 2. A shut-off valve 5 is installed on the heat storage tank drain pipe 7. If the liquid level in the heat storage tank 1 is too high or the water quality is not up to standard, the shut-off valve 5 can be opened to drain the water. The water from the heat storage tank 1 enters the fixed discharge expansion container 2 through the heat storage tank drain pipe 7. The top of the fixed discharge expansion container is connected to the expansion container exhaust steam pipe 9, and the bottom of the fixed discharge expansion container 2 is connected to the expansion container drain pipe 11. The expansion container exhaust steam pipe 9 has two branches. One branch is connected to the steam ejector 3, and the other branch is connected to the expansion container exhaust gas vent pipe 10.

[0017] Working process and principle: After the heat storage tank 1 drains water into the fixed discharge expansion tank 2, the pressure inside the fixed discharge expansion tank 2 is much lower than that inside the heat storage tank 1. The sudden pressure drop after the water enters the fixed discharge expansion tank 2 will cause the saturated water to flash. The steam generated by the flashing will enter the steam ejector 3 under the ejection action of the main steam. The main steam and exhaust steam will form usable low-pressure steam after passing through the steam ejector 3. At the same time, when the steam ejector 3 is not working, the exhaust steam venting pipe 10 of the expansion tank can discharge the exhaust steam in the fixed discharge expansion tank 2 to a safe place outdoors. The water in the fixed discharge expansion tank 2 that has not flashed can be discharged through the expansion tank drainage pipe 11. The main steam pipeline 6 has two branches. Branch 1 connects to the steam ejector 3, and branch 2 connects to the pressure reducing valve 4. When there is exhaust steam available in the constant discharge expansion vessel 2, the shut-off valve 5 on branch 1 opens and the shut-off valve 5 on branch 2 closes. The main steam in the heat storage tank 1 enters the steam ejector 3 through the main steam pipeline 6. The exhaust steam in the constant discharge expansion vessel also enters the steam ejector 3 under the action of high-velocity steam, and finally mixes to form usable low-pressure steam. When there is no exhaust steam available in the constant discharge expansion vessel 2 or the main steam pressure in the heat storage tank 1 is too low, the shut-off valve 5 on branch 1 closes and the shut-off valve 5 on branch 2 opens. The main steam in the heat storage tank 1 enters the pressure reducing valve 4 through the main steam pipeline 6. The main steam becomes usable low-pressure steam after passing through the pressure reducing valve 4.

Claims

1. A thermal storage tank with constant discharge and expansion vessel waste steam utilization system, comprising a thermal storage tank, a constant discharge and expansion vessel, a pressure reducing valve, a shut-off valve, a main steam pipeline, a thermal storage tank drain pipeline, a low-pressure steam pipeline, an expansion vessel waste steam pipeline, an expansion vessel waste steam venting pipeline to the atmosphere, and an expansion vessel drainage pipeline, wherein the top of the thermal storage tank is connected to the main steam pipeline, characterized in that: A steam ejector is installed on the main steam pipeline, with one end connected to the main steam pipeline and the other end connected to the low-pressure steam pipeline. The expansion tank exhaust steam pipeline has two branches, one branch connected to the steam ejector and the other branch connected to the expansion tank exhaust steam venting pipeline. The main steam pipeline has two branches, one branch connected to the steam ejector and the other branch connected to the pressure reducing valve. Shut-off valves are installed in the middle of both branch pipelines. The heat storage tank is connected to the fixed-discharge expansion tank through the bottom drain pipe, and the top of the fixed-discharge expansion tank is connected to the expansion tank exhaust steam pipeline.

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