Integrated fused salt steam generator suitable for flexible operation of coal-fired unit

Abstract

The invention discloses an integrated fused salt steam generator suitable for flexible operation of a coal-fired unit. Comprising a feed water inlet, a steam outlet, a fused salt inlet, a fused salt outlet, a shell, a preheating section baffle, a porous connecting pipe plate, a steam storage chamber baffle, a porous connecting pipe plate, an electric control valve, an overheating section baffle, a fused salt pipeline, a fused salt pipeline valve, a straight pipe, a preheating section, an evaporation section, a steam storage chamber, an overheating section, a spiral pipe and a fused salt branch inlet. The heat exchanger has the advantages that the preheating section, the evaporation section and the overheating section are integrated in the heat exchanger, the occupied space of equipment is reduced, and rapid load response is achieved; the fused salt branch can adjust the temperature of a fused salt outlet and prevent the fused salt temperature from deviating from a set value; reverse flowing and alternate reversing of cold and hot fluid are combined, the water supply vaporization space is enlarged, and the flow instability phenomena such as density wave oscillation are restrained; a steam storage chamber is arranged between the evaporation section and the overheating section, the steam yield can be rapidly changed by adjusting pressure through a valve, and the requirement for flexible operation of a coal-fired unit is met.

Description

Technical Field

[0001] This invention relates to the field of heat exchange equipment technology, and specifically to an integrated molten salt steam generator suitable for flexible operation of coal-fired power units. Background Technology

[0002] my country's new power system construction is accelerating, and the proportion of renewable energy power generation continues to increase. However, the volatility and uncertainty of wind and solar power pose a severe challenge to the safe and stable operation of the power grid. As the "ballast" of energy security, coal-fired power units urgently need to be transformed from traditional baseload power sources to flexible adjustment power sources. The flexibility transformation of coal-fired power units has become a core task for ensuring energy security and low-carbon transformation.

[0003] Molten salt thermal energy storage technology, with its advantages of long lifespan, high energy density, and low corrosivity, has become a key path for coupling energy storage and enhancing the flexible regulation capabilities of coal-fired power units. By coordinating the operation of the molten salt thermal energy storage system with the unit's steam-water system, flexible utilization of thermal energy across time and space can be achieved, effectively reducing the thermal inertia of coal-fired power units and improving load response rate. Currently, Huaneng Haimen Power Plant has achieved the first application of molten salt thermal energy storage coupled with a 1,000 kW unit technology in China, verifying the feasibility of this technical route. However, large-scale promotion still faces the challenge of core equipment compatibility.

[0004] Existing molten salt steam generators are insufficient to meet the stringent requirements of flexible operation in coal-fired power units. Firstly, traditional equipment often employs a decentralized functional module design, with preheaters, evaporators, and superheaters arranged independently. This results in a large space requirement and high thermal inertia, leading to delayed load response and an inability to match the rapid load changes required by coal-fired power units. Secondly, under high-parameter operating conditions, unreasonable heat exchange paths for hot and cold fluids and insufficient flow stability can easily trigger instability phenomena such as density wave oscillations, resulting in large fluctuations in outlet steam temperature. Thirdly, the integration process of molten salt steam generators and coal-fired power units is poorly compatible. Due to significant differences in equipment operating characteristics, problems such as asynchronous load response and decreased system energy efficiency are prone to occur, making it difficult to form a large-scale coupled solution.

[0005] Therefore, developing an integrated molten salt steam generator that can adapt to the flexible operation requirements of coal-fired power units, has a compact structure, fast response, and stable parameters has become a key technical requirement for breaking through the bottleneck of deep coupling between molten salt thermal storage and coal-fired power, and promoting the flexible transformation of coal-fired power units. Summary of the Invention

[0006] This invention provides an integrated molten salt steam generator suitable for flexible operation of coal-fired power units. Its technical purpose is to achieve integrated molten salt steam generator, reduce equipment space occupation, improve the heat exchange stability of hot and cold fluids, and adapt to the flexible operation requirements of coal-fired power units.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution: This invention provides an integrated molten salt steam generator suitable for flexible operation of coal-fired power units, comprising: a feedwater inlet, a steam outlet, a molten salt inlet, a molten salt outlet, a shell, a preheating section baffle, a lower perforated connecting tube sheet, a steam storage chamber baffle, an upper perforated connecting tube sheet, an electric regulating valve, a superheating section baffle, molten salt pipelines, molten salt pipeline valves, straight pipes, a preheating section, an evaporation section, a steam storage chamber, a superheating section, a spiral tube, and a molten salt branch inlet.

[0008] The upper and lower ends of the shell are respectively provided with a steam outlet and a water inlet. The inner cavity is provided with a preheating section baffle, a lower porous connecting tube sheet, a steam storage chamber baffle, an upper porous connecting tube sheet, an electric regulating valve, and a superheating section baffle from bottom to top. The preheating section is between the preheating section baffle and the lower porous connecting tube sheet, the evaporation section is between the lower porous connecting tube sheet and the steam storage chamber baffle, the steam storage chamber is between the steam storage chamber baffle and the upper porous connecting tube sheet, and the superheating section is between the electric regulating valve and the superheating section baffle. The side of the preheating section is provided with a molten salt branch inlet and a molten salt outlet, and the side of the superheating section is provided with a molten salt inlet.

[0009] Furthermore, the molten salt inlet is connected to the superheated section via a molten salt pipeline, and a molten salt pipeline valve is installed on the molten salt pipeline.

[0010] Furthermore, the evaporation section is provided with multiple straight pipes arranged at intervals, and the preheating section and superheating section are provided with spiral pipes.

[0011] Furthermore, feedwater enters the molten salt steam generator through the feedwater inlet, enters the tube side of the preheating section, and after reaching saturation temperature, enters the shell side of the evaporation section through the lower porous connecting tube sheet. After being completely vaporized into saturated steam, it enters the steam storage chamber, passes through the upper porous connecting tube sheet and the electric regulating valve, and enters the superheating section. Finally, the superheated steam passes through the hot section baffle and flows out of the molten salt steam generator through the steam outlet. Molten salt enters through the molten salt inlet, passes through the shell side of the superheating section, the steam storage chamber, and the tube side of the evaporation section in sequence, mixes with the molten salt that enters the preheating section through the molten salt branch inlet on the shell side of the preheating section, and flows out of the heat exchanger through the molten salt outlet.

[0012] The advantages of this invention are: (1) The preheating section, evaporation section and superheating section are integrated in the heat exchanger to reduce the space occupied by the equipment and achieve rapid load response; (2) The molten salt branch can adjust the molten salt outlet temperature by changing the temperature distribution of the hot and cold fluids in the preheating section, while ensuring the steam temperature, so as to prevent the molten salt outlet temperature from deviating from the set value. (3) The combination of reverse flow of hot and cold fluids and alternating flow increases the vaporization space of feedwater and suppresses flow instability phenomena such as density wave oscillation; (4) A steam storage chamber is arranged between the evaporation section and the superheating section. The steam output can be quickly changed by adjusting the pressure through valves to meet the flexible operation requirements of coal-fired units. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the molten salt steam generator described in this invention; Wherein: 1-Water supply inlet, 2-Steam outlet, 3-Molten salt inlet, 4-Molten salt outlet, 5-Shell, 6-Preheating section baffle, 7-Lower perforated connecting tube sheet, 8-Steam storage chamber baffle, 9-Upper perforated connecting tube sheet, 10-Electric regulating valve, 11-Superheating section baffle, 12-Molten salt pipeline, 13-Molten salt pipeline valve, 14-Straight pipe, 15-Preheating section, 16-Evaporation section, 17-Steam storage chamber, 18-Superheating section, 19-Spiral tube, 20-Molten salt branch inlet. Detailed Implementation

[0014] The technical solution of this application will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the scope of the invention. like Figure 1 As shown, the molten salt steam generator of the present invention includes: a water inlet 1, a steam outlet 2, a molten salt inlet 3, a molten salt outlet 4, a shell 5, a preheating section baffle 6, a lower porous connecting tube sheet 7, a steam storage chamber baffle 8, an upper porous connecting tube sheet 9, an electric regulating valve 10, a superheating section baffle 11, a molten salt pipeline 12, a molten salt pipeline valve 13, a straight pipe 14, a preheating section 15, an evaporation section 16, a steam storage chamber 17, a superheating section 18, a spiral tube 19, and a molten salt branch inlet 20.

[0015] In this embodiment, the upper and lower ends of the shell 5 are respectively provided with a steam outlet 2 and a water inlet 1. The inner cavity is provided with a preheating section baffle 6, a lower porous connecting tube sheet 7, a steam storage chamber baffle 8, an upper porous connecting tube sheet 9, an electric regulating valve 10, and a superheating section baffle 11 in sequence from bottom to top. The preheating section 15 is between the preheating section baffle 6 and the lower porous connecting tube sheet 7, the evaporation section 16 is between the lower porous connecting tube sheet 7 and the steam storage chamber baffle 8, the steam storage chamber 17 is between the steam storage chamber baffle 8 and the upper porous connecting tube sheet 9, and the superheating section 18 is between the electric regulating valve 10 and the superheating section baffle 11. The side of the preheating section 15 is provided with a molten salt branch inlet 20 and a molten salt outlet 4, and the side of the superheating section 18 is provided with a molten salt inlet 3.

[0016] In this embodiment, the molten salt inlet 3 is connected to the superheated section 18 through the molten salt pipeline 12, the molten salt branch inlet 20 is connected to the preheated section 15 through the molten salt pipeline, and a molten salt pipeline valve 13 is provided on the molten salt pipeline 12.

[0017] In this embodiment, the evaporation section 16 is provided with a heat exchange tube bundle 14, and the preheating section 15 and the superheating section 18 are provided with spiral tubes 19.

[0018] Feedwater enters the molten salt steam generator through feedwater inlet 1, flows into the tube side of preheating section 15, and after reaching saturation temperature, enters the shell side of evaporation section 16 through lower porous connecting tube sheet 7. After being completely vaporized into saturated steam, it enters the steam storage chamber 17, and then enters the superheating section 18 through upper porous connecting tube sheet 9 and electric regulating valve 10. Finally, the superheated steam passes through hot section baffle 11 and flows out of the molten salt steam generator through steam outlet 2. Molten salt enters through molten salt inlet 3, passes sequentially through the shell side of superheating section 18, steam storage chamber 17, and tube side of evaporation section 16, mixes with the molten salt entering preheating section 15 through molten salt branch inlet 20, and flows out of the heat exchanger through molten salt outlet 3.

[0019] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. An integrated molten salt steam generator suitable for flexible operation of coal-fired power units, characterized in that, include: Water inlet (1), steam outlet (2), molten salt inlet (3), molten salt outlet (4), shell (5), preheating section baffle (6), lower perforated connecting tube sheet (7), steam storage chamber baffle (8), upper perforated connecting tube sheet (9), electric regulating valve (10), superheating section baffle (11), molten salt pipeline (12), molten salt pipeline valve (13), straight pipe (14), preheating section (15), evaporation section (16), steam storage chamber (17), superheating section (18), spiral tube (19), molten salt branch inlet (20); The upper and lower ends of the shell (5) are respectively provided with a steam outlet (2) and a water inlet (1). The inner cavity is provided with a preheating section baffle (6), a lower porous connecting pipe plate (7), a steam storage chamber baffle (8), an upper porous connecting pipe plate (9), an electric regulating valve (10), and a superheating section baffle (11) from bottom to top. The preheating section (15) is between the preheating section baffle (6) and the lower porous connecting pipe plate (7), the evaporation section (16) is between the lower porous connecting pipe plate (7) and the steam storage chamber baffle (8), the steam storage chamber (17) is between the steam storage chamber baffle (8) and the upper porous connecting pipe plate (9), and the superheating section (18) is between the electric regulating valve (10) and the superheating section baffle (11). The side of the preheating section (15) is provided with a molten salt branch inlet (20) and a molten salt outlet (4), and the side of the superheating section (18) is provided with a molten salt inlet (3).

2. The integrated molten salt steam generator suitable for flexible operation of coal-fired power units according to claim 1, characterized in that, The molten salt inlet (3) is connected to the superheated section (18) through the molten salt pipeline (12), the molten salt branch inlet (20) is connected to the preheated section (15), and a molten salt pipeline valve (13) is installed on the molten salt pipeline (12).

3. The integrated molten salt steam generator suitable for flexible operation of coal-fired power units according to claim 1, characterized in that, The evaporation section (16) is equipped with a straight pipe (14), and the preheating section (15) and the superheating section (18) are equipped with spiral pipes (19).

4. An integrated molten salt steam generator suitable for flexible operation of coal-fired power units according to claim 1, characterized in that, Water enters the molten salt steam generator through the water inlet (1), enters the tube side of the preheating section (15), and after reaching the saturation temperature, it enters the shell side of the evaporation section (16) through the lower porous connecting tube sheet (7). After being completely vaporized into saturated steam, it enters the steam storage chamber (17), and enters the superheating section (18) through the upper porous connecting tube sheet (9) and the electric regulating valve (10). Finally, it is heated to the point that the superheated steam passes through the hot section baffle (11) and flows out of the molten salt steam generator through the steam outlet (2). Molten salt enters through the molten salt inlet (3), passes through the shell side of the superheating section (18), the steam storage chamber (17), and the tube side of the evaporation section (16) in sequence, and mixes with the molten salt that enters the preheating section (15) through the molten salt branch inlet (20) on the shell side of the preheating section (15). It then flows out of the heat exchanger through the molten salt outlet (3).

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