System for recovering and utilizing heat energy of high-temperature flue gas and treatment system

Abstract

The utility model discloses a kind of high-temperature flue gas's heat energy recycling system and processing system of stable electric energy can be output. Heat energy recycling system includes: first molten salt heat exchanger, with first low-temperature molten salt liquid inlet and first high-temperature molten salt liquid outlet;Molten salt heat accumulator, with feed inlet and discharge port;First steam generator, with high-temperature molten salt liquid inlet, first low-temperature molten salt liquid outlet, first water inlet and first steam exhaust port, high-temperature molten salt liquid inlet and discharge port are communicated, first low-temperature molten salt liquid outlet and first low-temperature molten salt liquid inlet are communicated;Power generation device, with steam air inlet, electric energy outlet and condensate water drain, steam air inlet and first steam exhaust port are communicated;Soft water tank, with condensate water inlet, third water inlet and soft water drain, condensate water inlet and condensate water drain are communicated, soft water drain and first water inlet are communicated;Salt melting tank, its second low-temperature molten salt liquid outlet and first low-temperature molten salt liquid inlet are communicated.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas heat utilization, and more specifically, to a heat energy recovery and utilization system and a treatment system for high-temperature flue gas. Background Technology

[0002] As global attention to energy efficiency and environmental protection continues to grow, energy efficiency levels are also constantly evolving. Improving energy efficiency facilitates the upgrading of energy-saving standards and is recognized globally as one of the most economical and effective energy-saving measures. Simultaneously, improved energy efficiency promotes the implementation of standard labeling, strengthens refined management of energy conservation and carbon reduction in key sectors, helps energy users to have clear objectives and a basis for action in their energy management, and can also forge new advantages for green industrial development, leading to green transformation and high-quality development of industries.

[0003] Industrial energy consumption accounts for over 70% of total societal energy consumption. Kilns and submerged arc furnaces, as major energy consumers in the building materials and metallurgical industries, contribute significantly to low industrial energy efficiency due to the waste of heat from their flue gas. Kilns have high exhaust temperatures and large volumes of flue gas, carrying away over 30% of total energy consumption. For example, semi-closed submerged arc furnaces have large flue gas volumes and temperatures exceeding 500℃; closed submerged arc furnaces have relatively smaller flue gas volumes, but their calorific value can reach 2600 kcal / Nm³. 3 The flue gas temperature can reach over 500℃. Therefore, utilizing the heat from the high-temperature flue gas generated by kilns is a key measure for achieving efficient energy recycling, cost reduction, and green emission reduction in the industrial sector.

[0004] Using waste heat boilers to generate steam from flue gas and then using that steam to generate electricity is a natural and effective way to achieve high energy efficiency. However, the flue gas volume and temperature in kilns are unstable, resulting in large fluctuations in the amount of steam generated, and the steam is not easy to store for long periods. This leads to unstable power generation and makes it impossible to meet the basic requirements for grid connection. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a high-temperature flue gas heat energy recovery and utilization system, a high-temperature flue gas treatment system, and a kiln flue gas treatment system that can output stable electrical energy. The technical solution is as follows:

[0006] A high-temperature flue gas heat recovery and utilization system includes:

[0007] The first molten salt heat exchanger has a first coil, a first air inlet and a first exhaust outlet. The first coil has a first low-temperature molten salt inlet and a first high-temperature molten salt outlet.

[0008] The molten salt thermal storage tank has an inlet and a outlet, with the inlet connected to the first high-temperature molten salt outlet.

[0009] The first steam generator has a third coil, a high-temperature molten salt inlet and a first low-temperature molten salt outlet. The third coil has a first water inlet and a first steam exhaust outlet. The high-temperature molten salt inlet is connected to the discharge outlet, and the first low-temperature molten salt outlet is connected to the first low-temperature molten salt inlet.

[0010] The power generation device has a steam inlet, an electrical outlet and a condensate drain outlet, with the steam inlet connected to the first steam exhaust outlet.

[0011] The soft water tank has a condensate inlet, a third inlet, and a soft water outlet. The condensate inlet and the condensate outlet are connected, and the soft water outlet is connected to the first inlet.

[0012] The salt melting tank has a heater, a molten salt inlet, and a second low-temperature molten salt drain outlet, which is connected to the first low-temperature molten salt inlet.

[0013] A high-temperature flue gas treatment system includes:

[0014] The aforementioned heat recovery and utilization system is used to process high-temperature flue gas and output low-temperature flue gas;

[0015] The purification device is used to purify low-temperature flue gas and output low-temperature clean gas.

[0016] The advantages of the aforementioned high-temperature flue gas heat energy recovery and utilization system and high-temperature flue gas treatment system are: overcoming the drawbacks of directly using water as a heat exchange medium, utilizing molten salt with characteristics such as large specific heat capacity, high thermal conductivity, high boiling point, low viscosity, weak corrosivity, and low cost as the heat energy carrier of the molten salt heat exchanger under normal pressure to absorb the heat energy of high-temperature flue gas with unstable gas volume and temperature, and then providing stable high-temperature molten salt to the steam generator as a heat medium through the molten salt heat storage device, thereby obtaining stable steam heat energy for stable power generation, making the energy form more efficient and improving energy utilization.

[0017] The first type of kiln flue gas treatment system includes:

[0018] The first molten salt heat exchanger has a first coil, a first air inlet and a first exhaust port. The first coil has a first low-temperature molten salt inlet and a first high-temperature molten salt outlet. The first air inlet is connected to the flue gas outlet of the kiln.

[0019] The purification device is used to purify the medium-temperature flue gas output from the first exhaust port and output medium-temperature clean gas.

[0020] The second molten salt heat exchanger has a second coil, a second air inlet and a second exhaust port. The second coil has a second low-temperature molten salt inlet and a second high-temperature molten salt outlet. The second air inlet is connected to the medium-temperature clean gas exhaust port of the purification device.

[0021] The molten salt thermal storage tank has an inlet and a outlet, with the inlet connected to the first high-temperature molten salt outlet and the second high-temperature molten salt outlet.

[0022] The first steam generator has a third coil, a high-temperature molten salt inlet and a first low-temperature molten salt outlet. The third coil has a first water inlet and a first steam exhaust outlet. The high-temperature molten salt inlet is connected to the discharge outlet, and the first low-temperature molten salt outlet is connected to the first low-temperature molten salt inlet and the second low-temperature molten salt inlet.

[0023] The power generation device has a steam inlet, an electrical outlet and a condensate drain outlet, with the steam inlet connected to the first steam exhaust outlet.

[0024] The soft water tank has a condensate inlet, a third inlet, and a soft water outlet. The condensate inlet and the condensate outlet are connected, and the soft water outlet is connected to the first inlet.

[0025] The salt melting tank has a heater, a molten salt inlet, and a second low-temperature molten salt drain outlet, which is connected to the first low-temperature molten salt inlet and the second low-temperature molten salt inlet.

[0026] Based on the above-mentioned high-temperature flue gas treatment system, the first kiln flue gas treatment system, by setting up two stages of molten salt heat exchangers and rationally arranging the positions of the two stages of molten salt heat exchangers before and after the purification device, not only fully recovers high-temperature heat and medium-temperature heat, but also achieves a particularly better purification effect on flue gas at medium temperature.

[0027] The second type of kiln flue gas treatment system includes:

[0028] The first molten salt heat exchanger has a first coil, a first air inlet and a first exhaust port. The first coil has a first low-temperature molten salt inlet and a first high-temperature molten salt outlet. The first air inlet is connected to the flue gas outlet of the kiln.

[0029] The molten salt thermal storage tank has an inlet and a outlet, with the inlet connected to the first high-temperature molten salt outlet.

[0030] The first steam generator has a third coil, a high-temperature molten salt inlet and a first low-temperature molten salt outlet. The third coil has a first water inlet and a first steam exhaust outlet. The high-temperature molten salt inlet is connected to the discharge outlet, and the first low-temperature molten salt outlet is connected to the first low-temperature molten salt inlet.

[0031] The dust removal device is used to remove dust from the medium-temperature flue gas output from the first exhaust port and output medium-temperature low-dust gas.

[0032] The second steam generator has a fourth coil, a third air inlet and a third exhaust port. The fourth coil has a second water inlet and a second steam exhaust port. The third air inlet is connected to the medium-temperature low-dust gas exhaust port of the dust removal device.

[0033] The power generation device has a steam inlet, an electrical outlet and a condensate drain outlet, and the steam inlet is connected to the first steam exhaust outlet and the second steam exhaust outlet.

[0034] The soft water tank has a condensate inlet, a third inlet, and a soft water outlet. The condensate inlet and the condensate outlet are connected, and the soft water outlet is connected to the first inlet and the second inlet.

[0035] A salt melting tank has a heater, a molten salt inlet, and a second low-temperature molten salt outlet, the second low-temperature molten salt outlet being connected to the first low-temperature molten salt inlet;

[0036] The purification device is used to purify the low-temperature, low-dust gas output from the third exhaust port and output low-temperature clean gas.

[0037] Based on the first type of kiln flue gas treatment system, the second type of kiln flue gas treatment system sets up two-stage steam generators and arranges the positions of the two-stage steam generators in a reasonable manner. The first steam generator uses high-temperature molten salt as a heat source, and the second steam generator uses the heat of medium-temperature low-dust gas as a heat source, so that the high-temperature heat and medium-temperature heat can be fully recovered.

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. Attached Figure Description

[0039] The accompanying drawings, which form part of this utility model, are used to aid in understanding this utility model. The content provided in the drawings and the related descriptions in this utility model can be used to explain this utility model, but do not constitute an undue limitation of this utility model. In the drawings:

[0040] Figure 1 This is a schematic diagram of the high-temperature flue gas heat energy recovery and utilization system and the high-temperature flue gas treatment system of Embodiment 1 of this utility model.

[0041] Figure 2 This is a schematic diagram of the high-temperature flue gas heat energy recovery and utilization system and the high-temperature flue gas treatment system of Embodiment 2 of this utility model.

[0042] Figure 3 This is a schematic diagram of the kiln flue gas treatment system of Embodiment 5 of this utility model.

[0043] Figure 4 This is a schematic diagram of the kiln flue gas treatment system of Embodiment 6 of this utility model.

[0044] The relevant markings in the above figures are:

[0045] 100 - First molten salt heat exchanger, 110 - First coil, 111 - First low-temperature molten salt inlet, 112 - First high-temperature molten salt outlet, 120 - First air inlet, 130 - First exhaust outlet, 200 - Second molten salt heat exchanger, 210 - Second coil, 211 - Second low-temperature molten salt inlet, 212 - Second high-temperature molten salt outlet, 220 - Second air inlet, 230 - Second exhaust outlet, 300 - First steam generator, 310 - Third coil, 311 - First water inlet, 312 - First steam outlet 320 - High-temperature molten salt inlet; 330 - First low-temperature molten salt outlet; 340 - Third low-temperature molten salt inlet; 350 - Third low-temperature molten salt outlet; 400 - Second steam generator; 410 - Fourth coil; 411 - Second water inlet; 412 - Second steam exhaust outlet; 420 - Third air inlet; 430 - Third exhaust outlet; 510 - Steam inlet; 520 - Power outlet; 530 - Condensate drain outlet; 540 - Steam drum; 550 - Power generation unit; 610 - Soft water tank; 611 - ... 612-Condensate inlet, 613-Third inlet, 620-Soft water outlet, 621-Molten salt tank, 622-Molten salt inlet, 623-Second low-temperature molten salt outlet, 624-Fourth low-temperature molten salt inlet, 625-Fourth low-temperature molten salt outlet, 630-Molten salt heat storage tank, 631-Feed inlet, 632-Discharge outlet, 633-Pressure regulator, 711-First liquid pump, 712-Second liquid pump, 713-Third liquid pump, 714-Fourth liquid pump, 715-Fifth liquid pump, 716-... Six-liquid pump, 717-Seventh-liquid pump, 721-Molten salt flow control valve, 722-Steam flow control valve, 731-First valve, 732-Second valve, 733-Third valve, 734-Fourth valve, 735-Fifth valve, 736-Sixth valve, 737-Seventh valve, 738-Eighth valve, 739-Ninth valve, 810-Kiln, 820-Dust removal device, 830-Purification device, 840-Induced draft device, 841-First induced draft fan, 842-Second induced draft fan, 850-Chimney. Detailed Implementation

[0046] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0047] The technical solutions and features provided in the various parts of this utility model, including the following description, can be combined with each other without conflict.

[0048] Furthermore, the embodiments of the present invention described below are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the protection scope of the present invention.

[0049] Regarding the terminology and units used in this utility model: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this utility model are intended to cover non-exclusive inclusion.

[0050] Example 1

[0051] Figure 1 This is a schematic diagram of the high-temperature flue gas heat energy recovery and utilization system and the high-temperature flue gas treatment system in this embodiment.

[0052] like Figure 1 The high-temperature flue gas heat recovery and utilization system shown includes a first molten salt heat exchanger 100, a molten salt heat storage tank 630, a first steam generator 300, a power generation device 550, a soft water tank 610, and a salt melting tank 620.

[0053] The first molten salt heat exchanger 100 has a first coil 110, a first air inlet 120, and a first exhaust port 130. The first coil 110 has a first low-temperature molten salt inlet 111 and a first high-temperature molten salt outlet 112. After the high-temperature flue gas flowing in from the first air inlet 120 exchanges heat with the low-temperature molten salt flowing in from the first low-temperature molten salt inlet 111, the high-temperature flue gas is converted into low-temperature flue gas and discharged from the first exhaust port 130 into the purification device 830. The low-temperature molten salt is converted into high-temperature molten salt and discharged from the first high-temperature molten salt outlet 112.

[0054] The molten salt thermal storage tank 630 has an inlet 631 and a outlet 632. The inlet 631 is connected to the first high-temperature molten salt outlet 112, and the molten salt thermal storage tank 630 is connected to a pressure regulator 633. The molten salt thermal storage tank 630 is a tank with an electrically heated structure, capable of keeping the high-temperature molten salt at a constant temperature. The high-temperature molten salt discharged from the first high-temperature molten salt outlet 112 is stored in the molten salt thermal storage tank 630, which helps to provide a stable heat medium to the first steam generator 300.

[0055] The first steam generator 300 has a third coil 310, a high-temperature molten salt inlet 320, and a first low-temperature molten salt outlet 330. The third coil 310 has a first water inlet 311 and a first steam exhaust outlet 312. The high-temperature molten salt inlet 320 is connected to the discharge outlet 632, and the first low-temperature molten salt outlet 330 is connected to the first low-temperature molten salt inlet 111, with a fourth liquid pump 714 between them. After the high-temperature molten salt flowing in from the high-temperature molten salt inlet 320 exchanges heat with the soft water flowing in from the first water inlet 311, the high-temperature molten salt is converted into low-temperature molten salt and discharged from the first low-temperature molten salt outlet 330 into the first low-temperature molten salt inlet 111. The soft water is converted into steam and discharged from the first steam exhaust outlet 312. A first liquid pump 711 and a molten salt flow control valve 721 are provided between the discharge outlet 632 and the high-temperature molten salt inlet 320.

[0056] The power generation device 550 has a steam inlet 510, an electrical outlet 520, and a condensate drain 530. The steam inlet 510 is connected to a first steam exhaust port 312. A steam reservoir 540 and a steam flow control valve 722 are provided between the first steam exhaust port 312 and the steam inlet 510. The steam discharged from the first steam exhaust port 312 is stored in the steam reservoir 540, which helps to provide a stable steam supply to the power generation device 550.

[0057] The soft water tank 610 has a condensate inlet 611, a third inlet 612 and a soft water outlet 613. The condensate inlet 611 is connected to the condensate outlet 530, and the soft water outlet 613 is connected to the first inlet 311, with a third liquid pump 713 between them.

[0058] The salt molten tank 620 includes a heater 621, a molten salt inlet 622, and a second low-temperature molten salt outlet 623. The first steam generator 300 also includes a third low-temperature molten salt inlet 340. The second low-temperature molten salt outlet 623 is connected to the third low-temperature molten salt inlet 340, and a fifth liquid pump 715 is provided between them, thereby achieving communication between the second low-temperature molten salt outlet 623 and the first low-temperature molten salt inlet 111. The first steam generator 300 also includes a third low-temperature molten salt outlet 350, and the salt molten tank 620 also includes a fourth low-temperature molten salt inlet 624. The third low-temperature molten salt outlet 350 is connected to the fourth low-temperature molten salt inlet 624, and a sixth liquid pump 716 is provided between them.

[0059] The high-temperature flue gas treatment system includes the aforementioned heat recovery and utilization system, purification device 830, induced draft device 840, and chimney 850. The heat recovery and utilization system processes the high-temperature flue gas and outputs low-temperature flue gas. Purification device 830 is used to purify the low-temperature flue gas and output low-temperature clean gas; the appropriate equipment for purification device 830 is selected based on the dust content, sulfur content, and nitrogen oxide content of the low-temperature flue gas. Induced draft device 840 is used to draw the low-temperature clean gas through chimney 850 for discharge.

[0060] Example 2

[0061] Figure 2 This is a schematic diagram of the high-temperature flue gas heat energy recovery and utilization system and the high-temperature flue gas treatment system in this embodiment.

[0062] like Figure 2 The high-temperature flue gas heat recovery and utilization system shown includes a first molten salt heat exchanger 100, a molten salt heat storage tank 630, a first steam generator 300, a power generation device 550, a soft water tank 610, and a salt melting tank 620.

[0063] The first molten salt heat exchanger 100 has a first coil 110, a first air inlet 120, and a first exhaust port 130. The first coil 110 has a first low-temperature molten salt inlet 111 and a first high-temperature molten salt outlet 112. After the high-temperature flue gas flowing in from the first air inlet 120 exchanges heat with the low-temperature molten salt flowing in from the first low-temperature molten salt inlet 111, the high-temperature flue gas is converted into low-temperature flue gas and discharged from the first exhaust port 130 into the purification device 830. The low-temperature molten salt is converted into high-temperature molten salt and discharged from the first high-temperature molten salt outlet 112.

[0064] The molten salt thermal storage tank 630 has an inlet 631 and a outlet 632. The inlet 631 is connected to the first high-temperature molten salt outlet 112, and the molten salt thermal storage tank 630 is connected to a pressure regulator 633. The molten salt thermal storage tank 630 is a tank with an electrically heated structure, capable of keeping the high-temperature molten salt at a constant temperature. The high-temperature molten salt discharged from the first high-temperature molten salt outlet 112 is stored in the molten salt thermal storage tank 630, which helps to provide a stable heat medium to the first steam generator 300.

[0065] The first steam generator 300 has a third coil 310, a high-temperature molten salt inlet 320, and a first low-temperature molten salt outlet 330. The third coil 310 has a first water inlet 311 and a first steam exhaust outlet 312. The high-temperature molten salt inlet 320 is connected to the discharge outlet 632, and the first low-temperature molten salt outlet 330 is connected to the first low-temperature molten salt inlet 111. After the high-temperature molten salt flowing in from the high-temperature molten salt inlet 320 exchanges heat with the soft water flowing in from the first water inlet 311, the high-temperature molten salt is converted into low-temperature molten salt and discharged from the first low-temperature molten salt outlet 330 into the first low-temperature molten salt inlet 111. The soft water is converted into steam and discharged from the first steam exhaust outlet 312. A first liquid pump 711 and a molten salt flow control valve 721 are provided between the discharge outlet 632 and the high-temperature molten salt inlet 320.

[0066] The power generation device 550 has a steam inlet 510, an electrical outlet 520, and a condensate drain outlet 530. The steam inlet 510 is connected to the first steam exhaust outlet 312 of the third coil 310. A steam reservoir 540 and a steam flow control valve 722 are provided between the first steam exhaust outlet 312 and the steam inlet 510. The steam discharged from the first steam exhaust outlet 312 is stored in the steam reservoir 540, which helps to provide a stable steam supply to the power generation device 550.

[0067] The soft water tank 610 has a condensate inlet 611, a third inlet 612 and a soft water outlet 613. The condensate inlet 611 is connected to the condensate outlet 530, and the soft water outlet 613 is connected to the first inlet 311, with a third liquid pump 713 between them.

[0068] The salt molten tank 620 has a heater 621, a molten salt inlet 622, and a second low-temperature molten salt outlet 623. The first steam generator 300 also has a third low-temperature molten salt inlet 340. The second low-temperature molten salt outlet 623 is connected to the third low-temperature molten salt inlet 340, and a fifth liquid pump 715 is provided between the two, thereby realizing the connection between the second low-temperature molten salt outlet 623 and the first low-temperature molten salt inlet 111.

[0069] Specifically, the heat energy recovery and utilization system of this embodiment also includes a first pipe connecting the first high-temperature molten salt drain port 112 and the feed port 631, a first branch pipe connected to the first low-temperature molten salt drain port 330, a fourth low-temperature molten salt drain port 625 disposed on the salt melting tank 620, a second branch pipe connected to the fourth low-temperature molten salt drain port 625, a third pipe connecting the first pipe and the first branch pipe, and a second pipe connecting the first low-temperature molten salt feed port 111, the first branch pipe, and the second branch pipe. The first pipe is equipped with a first valve 731, the first branch pipe with a second valve 732 and a fourth liquid pump 714, the second branch pipe with a third valve 733 and a seventh liquid pump 717, the second pipe with a fourth valve 734, and the third pipe with a fifth valve 735 and a second liquid pump 712. Compared with Embodiment 1, the heat energy recovery and utilization system of this embodiment can adaptively adjust the flow rate of low-temperature molten salt into the first coil 110 according to the temperature and volume of the flue gas and the heat exchange efficiency through the coordination of the various valves, making it more flexible in use.

[0070] Example 3

[0071] Compared with Embodiment 1 or 2, the difference of the high-temperature flue gas heat energy recovery and utilization system in this embodiment is that the shape of the first molten salt heat exchanger is adapted to the converter furnace cover, thereby enabling the recovery of converter heat.

[0072] Example 4

[0073] Compared with Embodiment 1 or 2, the difference of the high-temperature flue gas heat energy recovery and utilization system in this embodiment is that the shape of the first molten salt heat exchanger 100 is adapted to the furnace body of the kiln 810.

[0074] Example 5

[0075] Figure 3 This is a schematic diagram of the kiln flue gas treatment system in this embodiment.

[0076] like Figure 3 The kiln flue gas treatment system shown includes a first molten salt heat exchanger 100, a purification device 830, a second molten salt heat exchanger 200, a molten salt heat storage device 630, a first steam generator 300, a power generation device 550, a soft water tank 610, and a salt melting tank 620.

[0077] The first molten salt heat exchanger 100 has a first coil 110, a first air inlet 120, and a first exhaust port 130. The first coil 110 has a first low-temperature molten salt inlet 111 and a first high-temperature molten salt outlet 112. The first air inlet 120 is connected to the flue gas outlet of the kiln 810. After the kiln flue gas flowing in from the first air inlet 120 exchanges heat with the low-temperature molten salt flowing in from the first low-temperature molten salt inlet 111, the kiln flue gas is converted into medium-temperature flue gas and discharged into the purification device 830 from the first exhaust port 130. The low-temperature molten salt is converted into high-temperature molten salt and discharged from the first high-temperature molten salt outlet 112.

[0078] The purification device 830 is used to purify the medium-temperature flue gas output from the first exhaust port 130 and output medium-temperature clean gas. The purification device 830 includes a desulfurization tower, a dust collector, and a denitrification device connected in sequence.

[0079] The second molten salt heat exchanger 200 has a second coil 210, a second air inlet 220, and a second exhaust port 230. The second coil 210 has a second low-temperature molten salt inlet 211 and a second high-temperature molten salt outlet 212. The second air inlet 220 is connected to the medium-temperature clean gas exhaust port of the purification device 830. An exhaust fan 840 and a chimney 850 are located at the rear end of the second exhaust port 230. After the medium-temperature clean gas flowing in from the second air inlet 220 exchanges heat with the low-temperature molten salt flowing in from the second low-temperature molten salt inlet 211, the medium-temperature clean gas is converted into low-temperature clean gas and discharged from the second exhaust port 230 into the exhaust fan 840. The low-temperature molten salt is converted into high-temperature molten salt and discharged from the second high-temperature molten salt outlet 212.

[0080] The molten salt thermal storage tank 630 has an inlet 631 and a outlet 632. The inlet 631 is connected to the first high-temperature molten salt outlet 112 and the second high-temperature molten salt outlet 212. The molten salt thermal storage tank 630 is connected to a pressure regulator 633. The molten salt thermal storage tank 630 is a tank with an electrically heated structure, capable of keeping high-temperature molten salt at a constant temperature. The high-temperature molten salt discharged from the first high-temperature molten salt outlet 112 and the second high-temperature molten salt outlet 212 is stored in the molten salt thermal storage tank 630, which helps to provide a stable heat medium to the first steam generator 300.

[0081] The first steam generator 300 has a third coil 310, a high-temperature molten salt inlet 320, and a first low-temperature molten salt outlet 330. The third coil 310 has a first water inlet 311 and a first steam exhaust outlet 312. The high-temperature molten salt inlet 320 is connected to the discharge outlet 632, and the first low-temperature molten salt outlet 330 is connected to the first low-temperature molten salt inlet 111 and the second low-temperature molten salt inlet 211. After the high-temperature molten salt flowing in from the high-temperature molten salt inlet 320 exchanges heat with the soft water flowing in from the first water inlet 311, the high-temperature molten salt is converted into low-temperature molten salt and discharged from the first low-temperature molten salt outlet 330 into the first low-temperature molten salt inlet 111 and the second low-temperature molten salt inlet 211. The soft water is converted into steam and discharged from the first steam exhaust outlet 312. A first liquid pump 711 and a molten salt flow control valve 721 are provided between the discharge outlet 632 and the high-temperature molten salt inlet 320.

[0082] The first low-temperature molten salt drain port 330, the first low-temperature molten salt inlet port 111, and the second low-temperature molten salt inlet port 211 are connected to the first main road, the first branch road, and the second branch road. The first main road is equipped with a fourth liquid pump 714, the first branch road is equipped with a sixth valve 736, and the second branch road is equipped with a seventh valve 737.

[0083] The power generation device 550 has a steam inlet 510, an electrical outlet 520, and a condensate drain 530. The steam inlet 510 is connected to a first steam exhaust port 312. A steam reservoir 540 and a steam flow control valve 722 are provided between the first steam exhaust port 312 and the steam inlet 510. The steam discharged from the first steam exhaust port 312 is stored in the steam reservoir 540, which helps to provide a stable steam supply to the power generation device 550.

[0084] The soft water tank 610 has a condensate inlet 611, a third inlet 612 and a soft water outlet 613. The condensate inlet 611 is connected to the condensate outlet 530, and the soft water outlet 613 is connected to the first inlet 311, with a third liquid pump 713 between them.

[0085] The salt molten tank 620 includes a heater 621, a molten salt inlet 622, and a second low-temperature molten salt outlet 623. The first steam generator 300 also includes a third low-temperature molten salt inlet 340. The second low-temperature molten salt outlet 623 is connected to the third low-temperature molten salt inlet 340, and a fifth liquid pump 715 is provided between them, thereby enabling communication between the second low-temperature molten salt outlet 623 and the first low-temperature molten salt inlet 111 and the second low-temperature molten salt inlet 211. The first steam generator 300 also includes a third low-temperature molten salt outlet 350, and the salt molten tank 620 also includes a fourth low-temperature molten salt inlet 624. The third low-temperature molten salt outlet 350 is connected to the fourth low-temperature molten salt inlet 624, and a sixth liquid pump 716 is provided between them.

[0086] Example 6

[0087] Figure 4 This is a schematic diagram of the kiln flue gas treatment system in this embodiment.

[0088] like Figure 4 The kiln flue gas treatment system shown includes a first molten salt heat exchanger 100, a molten salt heat storage tank 630, a first steam generator 300, a dust removal device 820, a second steam generator 400, a power generation device 550, a soft water tank 610, a salt melting tank 620, and a purification device 830.

[0089] The first molten salt heat exchanger 100 has a first coil 110, a first air inlet 120, and a first exhaust port 130. The first coil 110 has a first low-temperature molten salt inlet 111 and a first high-temperature molten salt outlet 112. The first air inlet 120 is connected to the flue gas outlet of the kiln 810. After the kiln flue gas flowing in from the first air inlet 120 exchanges heat with the low-temperature molten salt flowing in from the first low-temperature molten salt inlet 111, the kiln flue gas is converted into medium-temperature flue gas and discharged into the dust removal device 820 from the first exhaust port 130. The low-temperature molten salt is converted into high-temperature molten salt and discharged from the first high-temperature molten salt outlet 112.

[0090] The molten salt thermal storage tank 630 has an inlet 631 and a outlet 632. The inlet 631 is connected to the first high-temperature molten salt outlet 112, and the molten salt thermal storage tank 630 is connected to a pressure regulator 633. The molten salt thermal storage tank 630 is a tank with an electrically heated structure, capable of keeping the high-temperature molten salt at a constant temperature. The high-temperature molten salt discharged from the first high-temperature molten salt outlet 112 is stored in the molten salt thermal storage tank 630, which helps to provide a stable heat medium to the first steam generator 300.

[0091] The first steam generator 300 has a third coil 310, a high-temperature molten salt inlet 320, and a first low-temperature molten salt outlet 330. The third coil 310 has a first water inlet 311 and a first steam exhaust outlet 312. The high-temperature molten salt inlet 320 is connected to the discharge outlet 632, and the first low-temperature molten salt outlet 330 is connected to the first low-temperature molten salt inlet 111. After the high-temperature molten salt flowing in from the high-temperature molten salt inlet 320 exchanges heat with the soft water flowing in from the first water inlet 311, the high-temperature molten salt is converted into low-temperature molten salt and discharged from the first low-temperature molten salt outlet 330 into the first low-temperature molten salt inlet 111. The soft water is converted into steam and discharged from the first steam exhaust outlet 312. A first liquid pump 711 and a molten salt flow control valve 721 are provided between the discharge outlet 632 and the high-temperature molten salt inlet 320.

[0092] The dust removal device 820 is used to remove dust from the medium-temperature flue gas output from the first exhaust port 130 and output medium-temperature low-dust gas. The dust removal device 820 preferably uses a porous metal membrane as the filter medium.

[0093] The second steam generator 400 has a fourth coil 410, a third air inlet 420, and a third exhaust port 430. The fourth coil 410 has a second water inlet 411 and a second steam exhaust port 412. The third air inlet 420 is connected to the medium-temperature, low-dust gas exhaust port of the dust removal device 820. The medium-temperature, low-dust gas flowing in from the third air inlet 420 is combusted and exchanges heat with the soft water flowing in from the second water inlet 411. The medium-temperature, low-dust gas is converted into low-temperature, low-dust gas and discharged into the purification device 830 from the third exhaust port 430. The soft water is converted into steam and discharged from the second steam exhaust port 412. A first induced draft fan 841 is provided between the medium-temperature, low-dust gas exhaust port and the third air inlet 420 of the dust removal device 820.

[0094] The power generation device 550 has a steam inlet 510, an electrical outlet 520, and a condensate drain 530. The steam inlet 510 is connected to a first steam exhaust port 312 and a second steam exhaust port 412. A steam reservoir 540 and a steam flow control valve 722 are provided between the first steam exhaust port 312, the second steam exhaust port 412, and the steam inlet 510. The steam discharged from the first steam exhaust port 312 and the second steam exhaust port 412 is stored in the steam reservoir 540, which helps to provide a stable steam supply to the power generation device 550.

[0095] The soft water tank 610 has a condensate inlet 611, a third inlet 612, and a soft water outlet 613. The condensate inlet 611 is connected to the condensate outlet 530, and the soft water outlet 613 is connected to the first inlet 311 and the second inlet 411. The soft water outlet 613, the first inlet 311, and the second inlet 411 are connected by a second main line, a third branch line, and a fourth branch line. A third liquid pump 713 is installed on the second main line, an eighth valve 738 is installed on the third branch line, and a ninth valve 739 is installed on the fourth branch line.

[0096] The salt molten tank 620 has a heater 621, a molten salt inlet 622, and a second low-temperature molten salt outlet 623. The first steam generator 300 also has a third low-temperature molten salt inlet 340. The second low-temperature molten salt outlet 623 is connected to the third low-temperature molten salt inlet 340, and a fifth liquid pump 715 is provided between the two, thereby realizing the connection between the second low-temperature molten salt outlet 623 and the first low-temperature molten salt inlet 111.

[0097] To enhance operational flexibility, the system includes a first pipe connecting the first high-temperature molten salt drain port 112 and the feed port 631; a first branch pipe connecting the first low-temperature molten salt drain port 330; a fourth low-temperature molten salt drain port 625 located on the molten salt tank 620; a second branch pipe connecting the fourth low-temperature molten salt drain port 625; a third pipe connecting the first pipe and the first branch pipe; and a second pipe connecting the first low-temperature molten salt feed port 111, the first branch pipe, and the second branch pipe. The first pipe is equipped with a first valve 731; the first branch pipe is equipped with a second valve 732 and a fourth liquid pump 714; the second branch pipe is equipped with a third valve 733 and a seventh liquid pump 717; the second pipe is equipped with a fourth valve 734; and the third pipe is equipped with a fifth valve 735 and a second liquid pump 712. This allows for adaptive adjustment of the flow rate of low-temperature molten salt into the first coil 110 based on the temperature, volume, and heat exchange efficiency of the kiln flue gas, resulting in greater operational flexibility.

[0098] The purification device 830 is used to purify the low-temperature, low-dust gas output from the third exhaust port 430 and output low-temperature clean gas. The purification device 830 includes a desulfurization tower, a dust collector, and a denitrification device connected in sequence. A second induced draft fan 842 and a chimney 850 are provided at the rear end of the low-temperature clean gas exhaust port of the purification device 830.

[0099] In the molten salt tank 620 of this invention, solid salt enters from the molten salt inlet 622 and is heated into flowing molten salt by the heater 621. Besides providing molten salt, the molten salt tank 620 can also be used to heat and melt circulating low-temperature molten salt when its flowability is poor. Additionally, when the system is shut down, molten salt from pipelines and equipment can be pumped into the molten salt tank 620 for storage to prevent solidification and system failure.

[0100] Molten salt flows in the pipeline under oxygen-free conditions and can be, but is not limited to, any combination of fluorides, chlorides, carbonates, sulfates, and nitrates. Nitrates (ternary or binary) have lower melting points, higher decomposition points, and wider effective operating temperatures, making them the preferred choice for molten salt. More preferably, mixed nitrates combining multiple metal elements can be used, such as ternary mixed nitrates composed of potassium nitrate, sodium nitrate, and sodium nitrite, or binary mixed nitrates composed of potassium nitrate and sodium nitrite.

[0101] The foregoing has described the relevant content of this utility model. Those skilled in the art will be able to implement this utility model based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of this utility model without inventive effort should fall within the protection scope of this utility model.

Claims

1. A high-temperature flue gas heat energy recovery and utilization system, characterized in that: include: The first molten salt heat exchanger (100) has a first coil (110), a first air inlet (120) and a first exhaust port (130). The first coil (110) has a first low-temperature molten salt inlet (111) and a first high-temperature molten salt outlet (112). The molten salt heat storage tank (630) has a feed inlet (631) and a discharge outlet (632), and the feed inlet (631) is connected to the first high-temperature molten salt discharge outlet (112); The first steam generator (300) has a third coil (310), a high-temperature molten salt inlet (320) and a first low-temperature molten salt outlet (330). The third coil (310) has a first water inlet (311) and a first steam exhaust outlet (312). The high-temperature molten salt inlet (320) is connected to the discharge outlet (632), and the first low-temperature molten salt outlet (330) is connected to the first low-temperature molten salt inlet (111). The power generation device (550) has a steam inlet (510), an electrical outlet (520) and a condensate drain outlet (530), and the steam inlet (510) is connected to the first steam exhaust outlet (312). The soft water tank (610) has a condensate inlet (611), a third inlet (612) and a soft water outlet (613). The condensate inlet (611) is connected to the condensate outlet (530), and the soft water outlet (613) is connected to the first inlet (311). The salt melting tank (620) has a heater (621), a molten salt inlet (622) and a second low-temperature molten salt drain (623), which is connected to the first low-temperature molten salt inlet (111).

2. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: It also includes a first liquid pump (711) and a molten salt flow control valve (721) located between the discharge port (632) and the high-temperature molten salt inlet (320); the molten salt heat storage tank (630) is connected to the pressure regulator (633).

3. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: Also includes: A first pipe is provided on the first high-temperature molten salt drain port (112) and the feed port (631), and a first valve (731) is provided on the first pipe; A first branch pipe is connected to the first low-temperature molten salt drain port (330), and a second valve (732) and a fourth liquid pump (714) are provided on the first branch pipe; A fourth low-temperature molten salt drain outlet (625) is provided on the salt melting tank (620); The second branch pipe is connected to the fourth low-temperature molten salt drain port (625), and the second branch pipe is equipped with a third valve (733) and a seventh liquid pump (717); A second pipe is connected to the first low-temperature molten salt inlet (111), the first branch pipe, and the second branch pipe. A fourth valve (734) is provided on the second pipe.

4. The high-temperature flue gas heat energy recovery and utilization system as described in claim 3, characterized in that: It also includes a third pipe connecting the first pipe and the first branch pipe, and a fifth valve (735) and a second liquid pump (712) are provided on the third pipe.

5. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: Also includes: A steam drum (540) and a steam flow control valve (722) are located between the first steam exhaust port (312) and the steam inlet (510); A third liquid pump (713) is installed between the first water inlet (311) and the soft water outlet (613); A fourth liquid pump (714) is installed between the first low-temperature molten salt inlet (111) and the first low-temperature molten salt outlet (330).

6. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: The first steam generator (300) also has a third low-temperature molten salt inlet (340), and the second low-temperature molten salt outlet (623) is connected to the third low-temperature molten salt inlet (340) and a fifth liquid pump (715) is provided between the two.

7. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: The first steam generator (300) also has a third low-temperature molten salt drain port (350), and the salt melting tank (620) also has a fourth low-temperature molten salt inlet port (624). The third low-temperature molten salt drain port (350) and the fourth low-temperature molten salt inlet port (624) are connected and a sixth liquid pump (716) is provided between them.

8. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: The shape of the first molten salt heat exchanger (100) is adapted to the converter cover.

9. The high-temperature flue gas heat energy recovery and utilization system as described in claim 1, characterized in that: The shape of the first molten salt heat exchanger (100) is adapted to the kiln body.

10. A high-temperature flue gas treatment system, characterized in that: include: The heat energy recovery and utilization system according to any one of claims 1-9 is used to process high-temperature flue gas and output low-temperature flue gas; Purification device (830) is used to purify low-temperature flue gas and output low-temperature clean gas.

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