Energy storage type heat exchanger and heating system for potassium sulfate production

Abstract

The application relates to an energy storage type heat exchanger and a heating system for potassium sulfate production, and belongs to the technical field of heat storage and heat exchange. The energy storage type heat exchanger comprises a heat preservation wall body provided with three placing cavities, high-temperature energy storage tanks, medium-temperature energy storage tanks and low-temperature energy storage tanks are respectively arranged in the three placing cavities, and the high-temperature energy storage tanks, the medium-temperature energy storage tanks and the low-temperature energy storage tanks are respectively used for heat energy recovery and utilization in a Mannheim process section, a Ziegler process section and a double decomposition process section of the heating system for potassium sulfate production. According to the temperature gradient requirements of the Mannheim process, the Ziegler process and the double decomposition process for preparing potassium sulfate, an integrated heat energy utilization system of waste heat recovery, cascade energy storage and accurate distribution is constructed, and closed loop recovery and efficient collaborative utilization of heat energy of the three processes are realized.

Description

Technical Field

[0001] This application belongs to the field of thermal storage and heat exchange technology, specifically relating to an energy storage heat exchanger and a heating system for potassium sulfate production. Background Technology

[0002] Potassium sulfate, a key chlorine-free potassium fertilizer in agricultural production, has a diverse production process characterized by varying raw material properties and product requirements, resulting in a technical system primarily based on the Mannheim process, assemblage process, and metathesis process. Different processes exhibit significant temperature gradients in their heating requirements, and the energy efficiency of the heating system directly determines the economic viability and environmental benefits of production. Currently, traditional heating methods are increasingly unable to meet the industry's demands for green and low-carbon development.

[0003] In the mainstream potassium sulfate preparation processes, the temperature requirements for heating vary significantly. The Mannheim process, a mature and mainstream process, requires its core reaction to be carried out at a high temperature of 500-600℃ to achieve complete conversion of potassium chloride and concentrated sulfuric acid. The combustion chamber temperature even needs to reach 1000-1400℃, typically relying on direct heating from gas burners, consuming 55-75 m³ of natural gas per ton of potassium sulfate. The assemblage process requires a medium-temperature environment of 280-320℃ to provide activation energy for the reaction and ensure the directional conversion of intermediate products. Although the metathesis process has relatively milder reaction conditions, the reaction stage requires temperature control at 65-100℃, and the crystallization process needs to maintain a stable temperature of around 40℃, often employing indirect steam heating.

[0004] In existing technologies, for the process sections with different temperature requirements, independent heating equipment is generally used for energy supply, resulting in a "separate heating" pattern. The Mannheim process often uses a dedicated gas-fired furnace to generate high-temperature heat by burning natural gas; the metathesis process often uses an electrically heated thermal oil furnace to create a medium-temperature environment; the double decomposition process relies on a low-pressure steam boiler to provide a low-temperature heat source, and steam preparation requires additional fuels such as coal or natural gas. These heating systems operate independently, with no heat transfer or sharing mechanism between the equipment, leading to cumulative costs for the purchase, installation, and maintenance of heating devices, while also occupying a large amount of production space.

[0005] More importantly, traditional heating methods suffer from severe energy waste, with overall energy utilization rates generally below 40%. The Mannheim process generates significant waste heat during high-temperature operation; the temperature of the reaction tail gas alone can reach 245-295°C, and even higher under some conditions. This tail gas, carrying substantial heat energy, is often simply cooled and then directly discharged in traditional processes, without effective utilization. Furthermore, the reaction within the Mannheim furnace is exothermic, and the released heat is lost through equipment dissipation and tail gas emissions, failing to participate in the system's energy cycle. In addition, the operating efficiency of independent heating equipment in each process segment has inherent limitations. For example, the heat conversion efficiency of gas-fired furnaces is approximately 80%-85%, and electric heating thermal oil furnaces suffer from about 15% electrical energy loss. The steam heating system of the metathesis process also experiences pipeline heat loss during steam transport. These multiple energy consumption factors further reduce overall energy efficiency.

[0006] This decentralized heating and waste heat model has brought multiple negative impacts. Economically, the operation of independent heating equipment requires continuous consumption of energy sources such as natural gas and electricity; the electricity consumption per ton of potassium sulfate can reach 65-80 kWh, and the added gas consumption significantly increases production costs. Environmentally, the large-scale combustion of fossil fuels leads to persistently high carbon emission intensity, and the directly emitted high-temperature exhaust gases cause thermal pollution. Technologically, the independent temperature control of each system makes it difficult to achieve dynamic heat balance, and frequent start-ups and shutdowns of heating equipment easily lead to temperature fluctuations, affecting reaction stability and product purity. Therefore, how to overcome the temperature barriers of different process stages and construct an integrated heating system that can coordinate waste heat recovery and cascade utilization has become a pressing technical challenge in the potassium sulfate production field, and is of great significance for improving the industry's energy efficiency, reducing production costs, and achieving a green transformation. Summary of the Invention

[0007] The technical problem to be solved by this application is to overcome the shortcomings of the prior art and provide an energy storage heat exchanger and a heating system for potassium sulfate production. This application addresses the temperature gradient requirements of three potassium sulfate preparation processes: the Mannheim process, the assemblage process, and the metathesis process. It constructs an integrated thermal energy utilization system that integrates waste heat recovery, cascaded energy storage, and precise distribution to achieve closed-loop recovery and efficient synergistic utilization of thermal energy from the three processes.

[0008] The technical solution adopted in this application to solve the problems existing in the prior art is:

[0009] An energy storage heat exchanger includes a cylindrical insulated wall with three placement chambers spaced vertically inside. Adjacent placement chambers are connected by a first heat exchange chamber and a second heat exchange chamber. A high-temperature energy storage tank, a medium-temperature energy storage tank, and a low-temperature energy storage tank are placed sequentially inside the three placement chambers from bottom to top. The high-temperature energy storage tank is filled with molten salt, while the medium-temperature and low-temperature energy storage tanks are filled with heat transfer oil.

[0010] The high-temperature energy storage tank is equipped with a heat exchange chamber, which is connected to a second liquid inlet pipe and a second liquid outlet pipe that extend to the outside of the insulation wall.

[0011] The medium-temperature energy storage tank is connected by a third liquid outlet pipe and a third liquid inlet pipe that extend to the outside of the insulation wall.

[0012] The cryogenic storage tank is connected by a fourth liquid outlet pipe and a fourth liquid inlet pipe that extend to the outside of the insulated wall.

[0013] Both the first and second heat exchange chambers are connected to a vacuum branch pipe and a gas supply pipe that extend to the outside of the insulation wall. Both the vacuum branch pipe and the gas supply pipe are connected to the vacuum control system outside the insulation wall.

[0014] The vacuum control system controls the vacuum level inside the first heat exchange chamber and the second heat exchange chamber.

[0015] Furthermore, both the upper and lower ends of the placement cavity are provided with placement platforms.

[0016] The high-temperature energy storage tank has annular first mounting plates protruding from the upper and lower ends of its outer side. A high-temperature resistant sealing gasket and a sealing ring are placed between the first mounting plate and the mounting platform.

[0017] The medium-temperature energy storage tank has annular second mounting plates protruding from the upper and lower ends of its outer side. A high-temperature resistant sealing gasket and a sealing ring are placed between the second mounting plate and the mounting platform.

[0018] The cryogenic energy storage tank has annular third mounting plates protruding from the upper and lower ends of its outer side. A high-temperature resistant sealing gasket and a sealing ring are placed between the third mounting plate and the mounting platform.

[0019] Furthermore, the vacuum control system includes a gas supply branch pipe connected to the gas supply pipe, a high-pressure gas tank, and a vacuum pump.

[0020] The gas filling branch pipe is connected in series with a first shut-off valve and a pressure regulating valve, and the two gas filling branch pipes are connected to the high-pressure gas tank through the gas filling main pipe.

[0021] Two vacuum branch pipes are connected to the main vacuum pipe through a first three-way valve. The main vacuum pipe is connected to the inlet of the vacuum pump through a suction pipe. A second shut-off valve is connected in series on the suction pipe.

[0022] Furthermore, the exhaust end of the vacuum pump is connected to the gas storage tank through a gas storage tank connecting pipe, and a second three-way valve is connected in series on the gas storage tank connecting pipe, with the remaining outlet of the second three-way valve connected to an vent pipe.

[0023] The gas storage tank is connected to the booster via a gas pipe. The booster pressurizes the gas output from the gas storage tank and then delivers it to the high-pressure gas tank.

[0024] Furthermore, the heat exchange chamber is annular, and an electric auxiliary heating device is installed inside the central through hole of the heat exchange chamber.

[0025] Furthermore, the high-temperature energy storage tank is equipped with a spiral tube inside, and the two ends of the spiral tube are respectively connected to an exhaust pipe and an air inlet pipe that pass through to the outside of the insulation wall. The exhaust pipe and the air inlet pipe are connected to the tail gas pipeline of the Mannheim reactor through valves.

[0026] A heating system for potassium sulfate production includes the aforementioned energy storage heat exchanger and a storage tank. The inlet of the storage tank is connected to the second outlet of the energy storage heat exchanger via a first reflux pipe. The outlet of the storage tank is connected to a heat exchange box inside a Mannheim reactor via a first heat transfer pipe. A first delivery pump is connected in series on the first heat transfer pipe. The heat exchange box inside the Mannheim reactor is connected to the second inlet of the energy storage heat exchanger via a second heat transfer pipe.

[0027] The tail gas pipe of the Mannheim reactor is connected to a tail gas connector. A third three-way valve is connected in series in the middle of the tail gas connector, and a fourth three-way valve is connected to the end of the tail gas connector. The remaining ports of the third three-way valve are connected to the inlet pipe of the energy storage heat exchanger through a first bypass pipe. The remaining two ports of the fourth three-way valve are connected to the post-treatment connection pipe and the exhaust pipe of the energy storage heat exchanger through a second bypass pipe, respectively.

[0028] The third liquid outlet pipe of the medium-temperature energy storage tank is connected to the first heating pipe, and the third liquid inlet pipe of the medium-temperature energy storage tank is connected to the second regenerating pipe. The first heating pipe is connected in series with the second transfer pump. The first heating pipe and the second regenerating pipe form a loop with the heating pipeline of the placement process section.

[0029] The fourth liquid outlet pipe of the cryogenic energy storage tank is connected to the second heating pipe, and the fourth liquid inlet pipe of the cryogenic energy storage tank is connected to the third regenerating pipe. The second heating pipe is connected in series with the third transfer pump. The second heating pipe and the third regenerating pipe form a loop with the heating pipeline of the metathesis process section.

[0030] Furthermore, the heat exchange box of the Mannheim reactor is fixed above the shell of the stirring structure, and a rotating shaft is fixed below the shell. The rotating shaft has a cavity inside, which is divided into an inlet chamber and an outlet chamber by a partition. The outer wall of the rotating shaft located outside the furnace body of the Mannheim reactor has an inlet port that is connected to the inlet chamber and an outlet port that is connected to the outlet chamber. The top of the inlet chamber is connected to the heat exchange box through a first connecting pipe, and the outlet chamber is connected to the heat exchange box through a second connecting pipe.

[0031] The shaft is fitted with three sealing rings. The inlet and outlet are respectively located in two interval areas formed by the three sealing rings. The outlet collection pipe and the inlet collection pipe are respectively fitted outside the two interval areas.

[0032] The liquid inlet collection pipe is connected to the liquid inlet, and the first liquid inlet pipe is connected externally.

[0033] The liquid collection pipe is connected to the liquid outlet, and the first liquid outlet pipe is connected externally.

[0034] The first liquid outlet pipe is connected to the second heat transfer pipe, and the first liquid inlet pipe is connected to the first heat transfer pipe.

[0035] Furthermore, the bottom surface of the reaction chamber inside the Mannheim reactor is flat, with a feed pipe running through the top of the reaction chamber and a discharge pipe running through the outside of the bottom surface of the reaction chamber. The stirring structure is located inside the reaction chamber.

[0036] The stirring structure includes a long strip-shaped shell, a paddle, and a control drive assembly.

[0037] Several spaced-apart paddles are rotatably mounted below the shell.

[0038] The control drive assembly includes a rotating shaft and a control component. The rotating shaft is fixedly connected to the housing, and the control component is used to adjust the angle of the paddle.

[0039] Furthermore, the control components include a rack, a sleeve, and a rotary drive device.

[0040] The top of the paddle is fixedly connected to a gear via a connecting shaft. The gear is located inside the housing, and the rack is slidably located inside the housing, meshing with all the gears.

[0041] The sleeve is fitted onto the rotating shaft, with the top of the sleeve extending into the interior of the housing and fixed with a gear ring, which meshes with a rack.

[0042] The rotary drive device is used to drive the sleeve to rotate relative to the shaft.

[0043] Compared with the prior art, the beneficial effects of this application are as follows:

[0044] (1) The insulated wall of the energy storage heat exchanger is equipped with three placement chambers, in which a high-temperature energy storage tank, a medium-temperature energy storage tank, and a low-temperature energy storage tank are placed in sequence. Adjacent tanks are connected by two heat exchange chambers to form a temperature gradient energy storage structure. The high-temperature energy storage tank corresponds to the Mannheim process, the medium-temperature energy storage tank corresponds to the deposition process, and the low-temperature energy storage tank corresponds to the metathesis process. They are connected to each process section through dedicated pipelines to form a circulation, so that the plant can generate potassium sulfate through three process methods under the premise of energy saving and consumption reduction, and achieve full coverage of low-end, medium-end and high-end potassium sulfate products, thereby increasing economic benefits.

[0045] (2) The high-temperature energy storage tank of the energy storage heat exchanger is equipped with a spiral tube connected to the tail gas pipeline of the Mannheim reactor to recover the heat of the tail gas at ≥450℃ and heat the molten salt. The high-temperature energy storage tank is equipped with an annular heat exchange chamber with an electric auxiliary heating device in the center to ensure that the temperature of the heat-conducting material is maintained when the temperature inside the high-temperature energy storage tank is below 500℃.

[0046] The Mannheim reactor has an inlet and outlet chamber inside its rotating shaft, and a detachable heat exchange box on its shell. The waste heat from the reaction is recovered through a circulating heat transfer medium and fed into the system's heating pipeline, thus absorbing the exothermic reaction of the Mannheim process. It can also preheat the reaction chamber of the Mannheim reactor in advance.

[0047] (3) The two heat exchange chambers of the energy storage heat exchanger are connected to the vacuum control system through the vacuum branch pipe and the gas supply pipe. The gas supply pipe is connected in series with the electric pressure regulating valve and the pressure sensor to form a closed-loop mechanism of "target pressure setting - real-time detection - deviation adjustment - stable maintenance" to accurately control the vacuum degree of the heat exchange chamber. The heat exchange efficiency of the two heat exchange chambers is adjusted by the vacuum degree to realize the gradient utilization of thermal energy.

[0048] (4) The gas extracted by the vacuum pump of the energy storage heat exchanger is stored in the gas storage tank, and after being pressurized by the booster, it is sent back to the high-pressure gas tank, reducing gas waste and reducing dependence on external gas sources.

[0049] (5) The heating system for potassium sulfate production constructs a temperature gradient through a three-temperature zone energy storage tank. The heat from the high-temperature energy storage tank can be adjusted through the vacuum degree of the heat exchange chamber and transferred to the medium-temperature energy storage tank as needed. The medium-temperature energy storage tank then transfers the heat to the low-temperature energy storage tank, realizing the tiered utilization of "high temperature for high temperature, medium temperature for medium temperature, and low temperature for low temperature". The heat from the three gradients is used for the three process paths of potassium sulfate production: the Mannheim process, the assemblage process, and the metathesis process, respectively. This changes the shortcomings of the existing technology, which uses independent heating equipment for each of the three process paths, and improves the comprehensive utilization efficiency of energy. Attached Figure Description

[0050] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0051] Figure 1 This is a process flow diagram of the heating system for potassium sulfate production in this application.

[0052] Figure 2 This is a process flow diagram of the external vacuum control section system of the energy storage heat exchanger in this application.

[0053] Figure 3 This is a first structural diagram of the energy storage heat exchanger of this application.

[0054] Figure 4 This is a second structural diagram of the energy storage heat exchanger of this application.

[0055] Figure 5 This is a first cross-sectional view of the energy storage heat exchanger of this application.

[0056] Figure 6 This is a second cross-sectional view of the energy storage heat exchanger of this application.

[0057] Figure 7 for Figure 6 Enlarged view of a portion of point A in the middle.

[0058] Figure 8 This is a third sectional view of the energy storage heat exchanger of this application.

[0059] Figure 9 This is the fourth sectional view of the energy storage heat exchanger of this application.

[0060] Figure 10 This is a partial cross-sectional view of the high-temperature energy storage tank in the energy storage heat exchanger of this application.

[0061] Figure 11 This is a structural diagram of the internal heat exchange chamber of a high-temperature energy storage tank.

[0062] Figure 12 This is a cross-sectional view of the Mannheim reactor.

[0063] Figure 13 This is a structural diagram of the stirring mechanism in a Mannheim reactor.

[0064] Figure 14 for Figure 13 A partial sectional view,

[0065] Figure 15 for Figure 14 Enlarged view of a section at point B in the middle.

[0066] Figure 16 This is a diagram of the stirring paddle structure in the mixing system.

[0067] Figure 17 This is a diagram of the rack and pinion structure in the stirring mechanism.

[0068] Figure 18 This is a structural diagram of the control drive assembly in the stirring structure.

[0069] Figure 19for Figure 18 sectional view,

[0070] Figure 20 This is a structural diagram of the rotating shaft assembly in the stirring structure.

[0071] Figure 21 for Figure 20 Sectional view,

[0072] Figure 22 This is a diagram of the sleeve structure in the stirring mechanism.

[0073] Figure 23 This is a diagram of the ring structure in the stirring mechanism.

[0074] In the diagram: 1-Shell, 101-Protruding plate, 2-Paddle plate, 201-Connecting shaft, 202-Gear, 3-Rack, 301-Groove, 4-Rotating shaft, 401-Bottom fixed flange, 402-Top fixed flange, 403-Baffle plate, 404-Liquid inlet chamber, 405-Liquid inlet, 406-Liquid outlet chamber, 407-Liquid outlet, 408-Sealing retaining ring, 5-Sleeve, 501-Gear ring, 502-Thickened tube, 503-Curved groove, 6-Ball head, 601-Connecting rod, 7-Collar ring, 8-Fixed... 9-Screw, 10-Servo motor, 11-Guide rod, 12-Liquid outlet collection pipe, 1201-First liquid outlet pipe, 13-Liquid inlet collection pipe, 1301-First liquid inlet pipe, 14-First connecting pipe, 15-Second connecting pipe, 16-First heat exchange box, 17-Second heat exchange box, 18-Third connecting pipe, 19-Reaction chamber, 1901-Feed pipe, 1902-Discharge chamber, 1903-Discharge pipe, 20-Blocking plate, 21-Telescopic drive device, 22-Furnace body, 2201-Tail gas pipe;

[0075] 23-Insulated wall, 2301-Placement cavity, 2302-Placing platform, 2303-First heat exchange cavity, 2304-Second heat exchange cavity, 2305-Inspection port, 2306-Inspection door, 24-High temperature energy storage tank, 2401-First mounting plate, 25-Heat exchange chamber, 2501-Second liquid inlet pipe, 2502-Second liquid outlet pipe, 2503-Finned plate, 26-Electric auxiliary heating device, 27-Spiral tube, 2701-Exhaust pipe, 2702-Air inlet Pipe, 28-Medium temperature energy storage tank, 2801-Third liquid outlet pipe, 2802-Third liquid inlet pipe, 2803-First pressure reducing pipe, 2804-Second access plate, 29-Cryogenic energy storage tank, 2901-Fourth liquid outlet pipe, 2902-Fourth liquid inlet pipe, 2903-Second pressure reducing pipe, 2904-Third access plate, 30-High temperature resistant sealing gasket, 31-Sealing ring, 32-Vacuum branch pipe, 33-Vacuum main pipe, 34-First three-way valve, 35-Gas supply pipe;

[0076] 36-Gas filling branch pipe, 3601-First shut-off valve, 3602-Pressure regulating valve, 3603-Pressure sensor, 37-Gas filling main pipe, 38-High-pressure gas tank, 39-Booster, 40-Booster connecting gas pipe, 41-Gas storage tank, 42-Gas storage tank connecting pipe, 43-Second three-way valve, 44-Drain pipe, 45-Vacuum pump, 46-Extraction pipe, 47-Second shut-off valve;

[0077] 48-Exhaust gas connection pipe, 49-Temperature sensor, 50-Third three-way valve, 51-Fourth three-way valve, 52-After-treatment connection pipe, 53-First bypass pipe, 54-Second bypass pipe, 55-First heat transfer pipe, 56-First transfer pump, 57-Second heat transfer pipe, 58-First return pipe, 59-Storage tank, 60-First heating pipe, 61-Second transfer pump, 62-Second regenerative pipe, 63-Second heating pipe, 64-Third transfer pump, 65-Third regenerative pipe, 66-First pressure reducing external connection pipe, 67-Second pressure reducing external connection pipe, 68-Gas collection tank. Detailed Implementation

[0078] The accompanying drawings provide a more detailed description of an energy storage heat exchanger and a heating system for potassium sulfate production, but these descriptions are not intended to limit the scope of this application.

[0079] Depend on Figures 3 to 11 As shown, an energy storage heat exchanger includes a cylindrical, enclosed insulated wall 23. The insulated wall 23 has three placement chambers 2301 spaced vertically inside. Adjacent placement chambers 2301 are connected by a first heat exchange chamber 2303 and a second heat exchange chamber 2304. A high-temperature energy storage tank 24, a medium-temperature energy storage tank 28, and a low-temperature energy storage tank 29 are placed inside the three placement chambers 2301 from bottom to top.

[0080] The high-temperature energy storage tank 24 is filled with molten salt at a temperature of 500 to 600°C. It is used to heat, preheat, and maintain the temperature of the process section for preparing potassium sulfate by the Mannheim process, while absorbing the exothermic reaction during the preparation of potassium sulfate by the Mannheim process.

[0081] Both the intermediate-temperature energy storage tank 28 and the cryogenic energy storage tank 29 are filled with heat-conducting oil. The intermediate-temperature energy storage tank 28 contains phase change energy storage materials, such as sodium nitrate-sodium nitrite composite phase change materials, which are packed inside a capsule. The internal temperature of the intermediate-temperature energy storage tank 28 is 280 to 320°C, used for heating and preheating the process section for preparing potassium sulfate via the assemblage method. The internal temperature of the cryogenic energy storage tank 29 is 80 to 90°C, used for heating and preheating the process section for preparing potassium sulfate via the metathesis method.

[0082] The high-temperature energy storage tank 24 has a heat exchange chamber 25 inside, and the heat exchange chamber 25 is connected by a second liquid inlet pipe 2501 and a second liquid outlet pipe 2502 that extend to the outside of the insulation wall 23. To improve heat exchange efficiency, several layers of finned plates 2503 are fixed to the outside of the heat exchange chamber 25. In order to maintain the temperature of the heat-conducting material inside the heat exchange chamber 25 when the internal temperature of the high-temperature energy storage tank 24 is below 500°C, in this embodiment, the heat exchange chamber 25 is annular, and an electric auxiliary heating device 26 is installed inside the central through hole of the heat exchange chamber 25. The heat-conducting material inside the heat exchange chamber 25 can be saturated steam or molten salt.

[0083] In order to improve the waste heat utilization efficiency of the Mannheim reactor tail gas, in this embodiment, the high-temperature energy storage tank 24 is provided with a spiral tube 27. The two ends of the spiral tube 27 are respectively connected to an exhaust pipe 2701 and an inlet pipe 2702 that pass through to the outside of the insulation wall 23. The exhaust pipe 2701 and the inlet pipe 2702 are connected to the Mannheim reactor tail gas pipeline through valves.

[0084] The medium-temperature energy storage tank 28 is connected to a third liquid outlet pipe 2801 and a third liquid inlet pipe 2802 that extend to the outside of the insulation wall 23. The low-temperature energy storage tank 29 is connected to a fourth liquid outlet pipe 2901 and a fourth liquid inlet pipe 2902 that extend to the outside of the insulation wall 23.

[0085] Both the first heat exchange chamber 2303 and the second heat exchange chamber 2304 are connected to a vacuum branch pipe 32 and a gas supply pipe 35 that extend to the outside of the insulation wall 23. Both the vacuum branch pipe 32 and the gas supply pipe 35 are connected to the vacuum control system outside the insulation wall 23.

[0086] The vacuum control system controls the vacuum level inside the first heat exchange chamber 2303 and the second heat exchange chamber 2304. By changing the vacuum level, the heat exchange efficiency is changed, so that the high-temperature energy storage tank 24 can heat the medium-temperature energy storage tank 28 or reduce or isolate heat transfer, and the medium-temperature energy storage tank 28 can heat the low-temperature energy storage tank 29 or reduce or isolate heat transfer.

[0087] To achieve adjustable vacuum levels, the sealing between the placement cavity 2301 and the first heat exchange cavity 2303 and the second heat exchange cavity 2304 must be ensured. Therefore, in this embodiment, the placement cavity 2301 is provided with a placement platform 2302 at both its upper and lower ends.

[0088] The high-temperature energy storage tank 24 has annular first mounting plates 2401 protruding from the upper and lower ends of its outer side. A high-temperature resistant sealing gasket 30 and a sealing ring 31 are sequentially placed between the first mounting plate 2401 and the mounting platform 2302.

[0089] The medium-temperature energy storage tank 28 has annular second mounting plates 2804 protruding from the upper and lower ends of its outer side. A high-temperature resistant sealing gasket 30 and a sealing ring 31 are sequentially placed between the second mounting plate 2804 and the mounting platform 2302.

[0090] The cryogenic energy storage tank 29 has annular third mounting plates 2904 protruding from the upper and lower ends of its outer side. A high-temperature resistant sealing gasket 30 and a sealing ring 31 are sequentially placed between the third mounting plate 2904 and the mounting platform 2302.

[0091] The high-temperature resistant sealing gasket 30 can be selected according to the temperature of the application environment, and can be made of rubber, aerogel or asbestos, etc. The sealing ring 31 is made of rigid material.

[0092] In order to enable maintenance of the equipment inside the placement cavity 2301, in this embodiment, 2 to 4 maintenance ports 2305 are provided on the inner wall of the placement cavity 2301 in a circular array around its axis. The maintenance ports 2305 are open, and a detachable maintenance door 2306 is provided at the opening. The maintenance door 2306 is composed of a rigid frame and thermal insulation material.

[0093] Depend on Figure 2 As shown, the vacuum control system includes a gas supply branch pipe 36 connected to the gas supply pipe 35, a high-pressure gas tank 38, and a vacuum pump 45.

[0094] A first shut-off valve 3601, a pressure regulating valve 3602, and a pressure sensor 3603 are connected in series on the gas filling branch pipe 36. The two gas filling branch pipes 36 are connected to the high-pressure gas tank 38 through the gas filling main pipe 37. The pressure regulating valve 3602 is an electrically controlled pressure regulating valve, and the pressure sensor 3603 detects the pressure after pressure regulation and provides feedback. In the vacuum control system, the cooperation between the electrically controlled pressure regulating valve 3602 and the pressure sensor 3603 constitutes a closed-loop pressure regulation mechanism, which can achieve precise pressure control during the gas filling process of the first heat exchange chamber 2303 and the second heat exchange chamber 2304, thereby stabilizing and regulating the vacuum degree of the heat exchange chamber. Different vacuum degrees are matched with different heat exchange efficiencies, and the heat exchange efficiency is determined by the pressure value detected by the pressure sensor 3603.

[0095] Two vacuum branch pipes 32 are connected to the vacuum main pipe 33 through the first three-way valve 34. The vacuum main pipe 33 is connected to the air inlet of the vacuum pump 45 through the air extraction pipe 46. A second shut-off valve 47 is connected in series on the air extraction pipe 46.

[0096] The exhaust end of the vacuum pump 45 is connected to the gas storage tank 41 through the gas storage tank connecting pipe 42. A second three-way valve 43 is connected in series on the gas storage tank connecting pipe 42, and the remaining outlet of the second three-way valve 43 is connected to the vent pipe 44.

[0097] The gas storage tank 41 is connected to the booster 39 via the booster pipe 40. The booster 39 pressurizes the gas output from the gas storage tank 41 and then delivers it to the high-pressure gas tank 38.

[0098] The steps for using the above-mentioned energy storage heat exchanger are as follows:

[0099] (a) Pre-start preparation stage for sealing inspection:

[0100] Inspect the sealing structure of each energy storage tank and placement chamber: Confirm that the high-temperature sealing gasket 30 and hard sealing ring 31 between the first mounting plate 2401 of the high-temperature energy storage tank 24, the second mounting plate 2804 of the medium-temperature energy storage tank 28, the third mounting plate 2904 of the low-temperature energy storage tank 29 and the placement platform 2302 of the placement chamber 2301 are intact, without damage or displacement. Ensure the sealing between the placement chamber 2301 and the first heat exchange chamber 2303 and the second heat exchange chamber 2304 to provide a basis for subsequent vacuum adjustment.

[0101] Valve and Piping Inspection: Check the status of all valves in the vacuum control system, including the first shut-off valve 3601 and pressure regulating valve 3602 on the gas supply branch pipe 36, the first three-way valve 34 connected to the vacuum branch pipe 32, the second shut-off valve 47 on the gas extraction pipe 46, and the second three-way valve 43 on the gas storage tank connecting pipe 42, all of which should be closed. Check that the connections of the second liquid inlet pipe 2501, the second liquid outlet pipe 2502, the third liquid outlet pipe 2801, the third liquid inlet pipe 2802, the fourth liquid outlet pipe 2901, the fourth liquid inlet pipe 2902, and the exhaust pipe 2701 and inlet pipe 2702 of the spiral pipe 27 to the corresponding process pipelines are secure and leak-free.

[0102] Medium and equipment status check: Confirm that the molten salt filling in the high-temperature energy storage tank 24 is sufficient, the heat transfer oil and capsule-encapsulated sodium nitrate-sodium nitrite composite phase change material filling in the medium-temperature energy storage tank 28 are normal, and the heat transfer oil filling in the low-temperature energy storage tank 29 is sufficient; check that the power supply and connection lines of the electric auxiliary heating device 26, vacuum pump 45, booster 39, high-pressure gas tank 38, and gas storage tank 41 are normal and can be started normally.

[0103] (II) Waste heat recovery and storage during the high-temperature energy storage tank heat storage stage:

[0104] The inlet pipe 2702 and outlet pipe 2701 of the spiral tube 27 are connected to the exhaust gas pipeline of the Mannheim reactor via valves. Opening the connecting valves allows the exhaust gas from the Mannheim reactor to enter the spiral tube 27 through the inlet pipe 2702. The heat from the exhaust gas is transferred to the molten salt in the high-temperature energy storage tank 24, completing waste heat recovery. The exhaust gas is then discharged through the outlet pipe 2701. During this process, the heat exchange efficiency is enhanced by the finned plates 2503 outside the heat exchange chamber 25, gradually raising the temperature of the molten salt to 500-600℃.

[0105] Electric auxiliary heating: If the internal temperature of the high-temperature energy storage tank 24 is lower than 500℃, the electric auxiliary heating device 26 in the central through hole of the heat exchange chamber 25 is activated to maintain the temperature of the heat-conducting material inside the heat exchange chamber 25 through electric auxiliary heating, so as to ensure that the temperature of the molten salt in the high-temperature energy storage tank 24 is stable at 500-600℃.

[0106] (III) Heating, preheating and heat preservation of Mannheim process sections in different process stages:

[0107] Open the valves of the second inlet pipe 2501 and the second outlet pipe 2502 of the heat exchange chamber 25 of the high-temperature energy storage tank 24 to allow the heat-conducting material to circulate between the heat exchange chamber 25 and the pipeline of the potassium sulfate preparation section of the Mannheim process. The molten salt at 500-600℃ in the high-temperature energy storage tank 24 provides the heat required for heating, preheating and heat preservation of the process section, while absorbing the heat released by the reaction of the process section, so as to realize the recovery and utilization of heat.

[0108] The principle of adjusting the heat transfer between the high-temperature energy storage tank 24, the medium-temperature energy storage tank 28, and the low-temperature energy storage tank 29 by changing the vacuum level is as follows:

[0109] Heat transfer is mainly achieved through three mechanisms: heat conduction, heat convection, and heat radiation. In this energy storage heat exchanger, the gas in the first heat exchange chamber 2303 and the second heat exchange chamber 2304 is the main medium for heat conduction and heat convection. Changes in vacuum directly affect the density of gas molecules in the chamber: the lower the vacuum, the greater the gas molecule density, the stronger the heat conduction and heat convection, and the higher the heat exchange efficiency; the higher the vacuum, the smaller the gas molecule density, the weaker the heat conduction and heat convection, and the lower the heat exchange efficiency; when an extremely high vacuum is reached, there are very few gas molecules, and heat conduction and heat convection can be basically ignored, with heat mainly transferred by heat radiation. At this point, the heat exchange efficiency is extremely low, and an approximate insulation state can be achieved.

[0110] The medium-temperature energy storage tank is put into use for heating and preheating of the process section of the deposition process:

[0111] Adjusting the vacuum level of the first heat exchange chamber 2303: If the high-temperature energy storage tank 24 is required to heat the medium-temperature energy storage tank 28, the first shut-off valve 3601 and the pressure regulating valve 3602 are opened through the gas supply branch pipe 36. Gas is supplied from the high-pressure gas tank 38 through the gas supply main pipe 37 and the gas supply branch pipe 36 to the first heat exchange chamber 2303, thereby increasing the number and density of gas molecules in the chamber, increasing heat transfer, and raising the temperature inside the medium-temperature energy storage tank 28 to 280-320℃.

[0112] If heat transfer needs to be reduced, close the first shut-off valve 3601, open the first three-way valve 34, start the vacuum pump 45, and evacuate the first heat exchange chamber 2303 through the vacuum branch pipe 32 to reduce the number and density of gas molecules in the chamber, reduce heat conduction and convection between the high-temperature energy storage tank 24 and the medium-temperature energy storage tank 28, and reduce heat exchange efficiency.

[0113] If heat transfer needs to be isolated, the first heat exchange chamber 2303 is continuously evacuated to a high vacuum state, minimizing gas heat transfer and achieving heat insulation.

[0114] Once the temperature inside the medium-temperature energy storage tank 28 stabilizes at 280-320℃, the valves of the third liquid outlet pipe 2801 and the third liquid inlet pipe 2802 are opened to allow the internal heat transfer oil to circulate with the pipeline of the potassium sulfate preparation section by the placement method, providing heating and preheating heat for the process section.

[0115] The cryogenic energy storage tank is put into use for heating and preheating of the metathesis process section:

[0116] Adjusting the vacuum level of the second heat exchange chamber 2304: If the medium-temperature energy storage tank 28 needs to heat the low-temperature energy storage tank 29, open the first shut-off valve 3601 and the pressure regulating valve 3602 through the gas supply branch pipe 36, and supply gas from the high-pressure gas tank 38 through the gas supply main pipe 37 and the gas supply branch pipe 36 to the second heat exchange chamber 2304, increase the number and density of gas molecules in the chamber, increase heat transfer, and raise the temperature inside the low-temperature energy storage tank 29 to 80-90℃;

[0117] If it is necessary to reduce or block heat transfer, the second heat exchange chamber 2304 is evacuated to increase the vacuum level and weaken or block heat transfer.

[0118] Low-temperature energy storage tank power supply: When the temperature inside the low-temperature energy storage tank 29 stabilizes at 80-90℃, open the valves of the fourth liquid outlet pipe 2901 and the fourth liquid inlet pipe 2902 to circulate the internal heat transfer oil with the pipeline of the potassium sulfate preparation section by metathesis method, and provide heating and preheating heat for the process section.

[0119] (iv) Gas recycling stage of vacuum control system:

[0120] When evacuating the first heat exchange chamber 2303 or the second heat exchange chamber 2304, the second shut-off valve 47 on the evacuation pipe 46 is opened. The gas extracted by the vacuum pump 45 enters the gas storage tank 41 through the vacuum main pipe 33 and the evacuation pipe 46. If the pressure inside the gas storage tank 41 is greater than the threshold, increasing the back pressure of the vacuum pump 45 will affect the evacuation effect. In this case, the gas flow direction is changed through the second three-way valve 43, so that the gas is discharged through the vent pipe 44.

[0121] When the gas in the gas storage tank 41 reaches a certain amount, the booster 39 is started. The gas in the gas storage tank 41 is pressurized and transported to the high-pressure gas tank 38 through the gas pipe 40 connected to the booster, so as to realize the recycling of gas and reduce gas waste.

[0122] Depend on Figure 1As shown, a heating system for potassium sulfate production includes the aforementioned energy storage heat exchanger and a storage tank 59. The inlet end of the storage tank 59 is connected to the second outlet pipe 2502 of the energy storage heat exchanger via a first return pipe 58. The outlet end of the storage tank 59 is connected to a heat exchange box inside the Mannheim reactor via a first heat transfer pipe 55. A first delivery pump 56 is connected in series on the first heat transfer pipe 55. The heat exchange box inside the Mannheim reactor is connected to the second inlet pipe 2501 of the energy storage heat exchanger via a second heat transfer pipe 57.

[0123] The tail gas pipe 2201 of the Mannheim reactor is connected to a tail gas connector 48. A third three-way valve 50 is connected in series in the middle of the tail gas connector 48, and a fourth three-way valve 51 is connected to the end of the tail gas connector 48. The remaining ports of the third three-way valve 50 are connected to the inlet pipe 2702 of the energy storage heat exchanger through a first bypass pipe 53. The remaining two ports of the fourth three-way valve 51 are connected to the post-treatment connection pipe 52 and the exhaust pipe 2701 of the energy storage heat exchanger through a second bypass pipe 54, respectively.

[0124] The exhaust pipe 48 is equipped with a temperature sensor 49. When the temperature sensor 49 detects a temperature less than 450°C, the exhaust pipe 48 is not connected to the first bypass pipe 53 and the second bypass pipe 54.

[0125] The third liquid outlet pipe 2801 of the medium-temperature energy storage tank 28 is connected to the first heating pipe 60, and the third liquid inlet pipe 2802 of the medium-temperature energy storage tank 28 is connected to the second regenerating pipe 62. The first heating pipe 60 is connected in series with the second transfer pump 61. The first heating pipe 60 and the second regenerating pipe 62 form a loop with the heating pipeline of the placement process section.

[0126] The fourth liquid outlet pipe 2901 of the low-temperature energy storage tank 29 is connected to the second heating pipe 63, and the fourth liquid inlet pipe 2902 of the low-temperature energy storage tank 29 is connected to the third regenerating pipe 65. The second heating pipe 63 is connected in series with the third transfer pump 64. The second heating pipe 63 and the third regenerating pipe 65 form a loop with the heating pipeline of the metathesis process section.

[0127] A first pressure-reducing pipe 2803 with a valve runs through the outside of the medium-temperature energy storage tank 28, and a second pressure-reducing pipe 2903 with a valve runs through the outside of the low-temperature energy storage tank 29. The first pressure-reducing pipe 2803 is connected to the gas collecting tank 68 through a first pressure-reducing external connecting pipe 66, and the second pressure-reducing pipe 2903 is connected to the gas collecting tank 68 through a second pressure-reducing external connecting pipe 67.

[0128] The medium-temperature energy storage tank 28 and the low-temperature energy storage tank 29 are connected to the gas collecting tank 68 via the first pressure reducing pipe 2803 and the second pressure reducing pipe 2903, forming a pressure stabilization system to address pressure fluctuations within the tanks. Its core function is to offset sudden pressure increases or decreases caused by temperature changes or the addition of heat transfer oil through gas migration and balancing mechanisms, ensuring that the internal pressure of the energy storage tank remains stable within a safe threshold, while simultaneously guaranteeing heat transfer efficiency and equipment operational safety.

[0129] Taking the medium-temperature energy storage tank 28 as an example, when the temperature of the medium-temperature energy storage tank 28 rises due to absorbing heat from the high-temperature energy storage tank 24, the internal heat transfer oil will increase in volume due to thermal expansion, and some low-boiling-point components may vaporize to produce steam. In addition, the capsule-encapsulated sodium nitrate-sodium nitrite composite phase change material may compress the internal air due to volume expansion during the phase change process, or a small amount of phase change material vapor may leak from the micro-slits of the capsule, causing a sudden increase in the pressure inside the tank. At this time, if the pressure inside the tank exceeds the preset safety value, the valve of the first pressure reducing pipe 2803 can be opened, and the excess gas inside the tank flows into the gas collecting tank 68 through the first pressure reducing external pipe 66. The gas collecting tank 68, as a volumetric buffer space, can temporarily store these gases to prevent the tank body from deforming, the sealing gasket from failing, or the heat transfer oil from leaking due to the continuous increase in pressure inside the tank, thus achieving pressure relief and stabilization.

[0130] Since the gas emitted is mostly gas containing vaporized heat transfer oil, it is collected in a unified manner through the gas collection tank 68, which facilitates the reuse of the heat transfer oil.

[0131] When the medium-temperature energy storage tank 28 releases heat to the low-temperature energy storage tank 29, or when the process section stops extracting heat, causing the temperature to drop, the heat transfer oil vapor inside the tank will condense into a liquid state, resulting in volume contraction. When the phase change material changes from a liquid state back to a solid state, its volume decreases, increasing the space inside the tank and potentially creating negative pressure. If the pressure inside the tank is lower than the preset lower limit, the valve of the first pressure reducing pipe 2803 can be opened, and the gas stored in the gas collecting tank 68 will flow back to the energy storage tank due to the negative pressure inside the tank, replenishing the internal space and achieving pressure replenishment and stabilization.

[0132] Based on the requirements of the heating system for potassium sulfate production, this embodiment improves the structure of the reaction chamber 19 of the Mannheim reactor. The furnace body 22, the burner outside the reaction chamber 19, and the stirring drive device outside the furnace body 22 are the same as the original Mannheim reactor and are not changed.

[0133] The bottom surface of the reaction chamber 19 is planar. A feed pipe 1901 is connected through the top of the reaction chamber 19, and a discharge pipe 1903 is connected through the outer side of the bottom surface of the reaction chamber 19, which is arranged downwards. In this embodiment, a through opening is provided on the outer side of the bottom surface of the reaction chamber 19, extending from the bottom surface of the reaction chamber 19 to the side wall. A discharge chamber 1902 is provided outside the reaction chamber 19 to cover the through opening, and the discharge pipe 1903 is connected through the bottom of the discharge chamber 1902.

[0134] The discharge chamber 1902 is equipped with a sliding block plate 20, which blocks the through opening of the reaction chamber 19. After the block plate 20 is blocked, the inner wall of the block plate 20 is consistent with the inner wall of the reaction chamber 19.

[0135] A telescopic drive device 21 is fixed to the outside of the furnace body 22. The telescopic rod of the telescopic drive device 21 is fixedly connected to the blocking plate 20. The telescopic drive device 21 can be an electric telescopic rod or a pneumatic telescopic rod.

[0136] The stirring structure includes a long strip-shaped shell 1, a paddle 2, and a control drive assembly; several paddles 2 arranged at intervals are rotatably disposed below the shell 1; the control drive assembly includes a rotating shaft 4 and a control component, the rotating shaft 4 being fixedly connected to the shell 1, and the control component being used to adjust the angle of the paddles 2.

[0137] In existing technologies, the bottom surface of the reaction chamber is curved, higher in the middle and lower at the edges, with the discharge pipe connected to the lowest point of the curved edge. This is because the angle of the paddles or rake teeth of the stirring mechanism in existing technologies cannot be adjusted, and material discharge can only be achieved through the curvature of the reaction chamber's bottom surface. This arrangement is primarily for material discharge considerations, but because the bottom surface is curved, the material distribution inside the reaction chamber is uneven, which in turn affects the reaction effect to some extent and reduces the purity of the reaction product, potassium sulfate.

[0138] In order to ensure the mixing effect and uniform material distribution, the bottom surface of the reaction chamber 19 is set to be flat. During the discharge process after the reaction, the blocking plate 20 moves outward, opening the passage between the reaction chamber 19 and the discharge chamber 1902. The flow direction of the material is changed by adjusting the angle of the stirring structure paddle 2, and the material is pushed into the discharge chamber 1902 in sequence, and then discharged through the discharge pipe 1903.

[0139] The stirring structure inside the reaction chamber 19 includes a long strip-shaped shell 1, a paddle 2, and a control drive assembly.

[0140] The shell 1 is composed of two parts, upper and lower, which are fixedly connected by bolts.

[0141] Several spaced-apart paddles 2 are rotatably disposed below the housing 1. The paddles 2 are arc-shaped plates, and a gear 202 is fixedly connected to the top of the plate via a connecting shaft 201. The gear 202 is rotatably disposed inside the housing 1.

[0142] The control drive assembly includes a rotating shaft 4 and a control component. The rotating shaft 4 is fixedly connected to the housing 1, and the control component is used to adjust the angle of the paddle 2.

[0143] The control components include a rack 3, a sleeve 5, and a rotary drive device.

[0144] The rack 3 is slidably disposed inside the housing 1. In order to limit its movement and make it slide only along a predetermined path, in this embodiment, the inner wall of the housing 1 is provided with a protruding plate 101, and the end face of the rack 3 is provided with a recessed groove 301. The groove 301 is engaged with the protruding plate 101, and the rack 3 is meshed with all the gears 202 inside the housing 1.

[0145] The sleeve 5 is coaxially sleeved on the rotating shaft 4, and the top of the sleeve 5 passes through the inside of the housing 1 and is fixed with a toothed ring 501, which meshes with the rack 3.

[0146] The rotary drive device is used to drive the sleeve 5 to rotate relative to the rotating shaft 4.

[0147] To achieve a fixed connection between the rotating shaft 4 and the housing 1 without affecting the arrangement of the gear ring 501, in this embodiment, a top fixing flange 402 is provided at the top of the rotating shaft 4, extending above the outside of the housing 1. The top fixing flange 402 is fixedly connected to the top surface of the housing 1 by bolts. A bottom fixing flange 401 is provided at the bottom of the rotating shaft 4, and the bottom fixing flange 401 is connected to the output end of the stirring drive device that drives the stirring structure of the Mannheim furnace by a coupling or bolts.

[0148] The rotary drive device includes a lifting mechanism, a collar 7, and a ball head 6 fixedly connected to the inner side of the collar 7 via a connecting rod 601.

[0149] The sleeve 5 has a thickened tube 502 at the bottom, and the thickened tube 502 has a curved groove 503 arranged from bottom to top on the outside. The ball head 6 is slidably disposed inside the curved groove 503.

[0150] The lifting mechanism drives the collar 7 to move up and down, thereby changing the height of the ball head 6. Since the ball head 6 slides inside the curved groove 503, the change in the height of the ball head 6 can cause the thickened tube 502, the sleeve 5, and the gear ring 501 to rotate relative to the rotating shaft 4. The rotation of the gear ring 501 causes the rack 3 to move, which in turn causes the gear 202 to rotate. The rotation of the gear 202 causes the propeller 2 to rotate, changing the angle of the propeller 2.

[0151] By changing the angle of the paddle 2, the stirring direction and effect of the material inside the Mannheim furnace can be changed, thus better matching different working conditions.

[0152] In order to optimize the driving effect of the ball head 6 on the thickened tube 502 when it moves, in this embodiment, two ball heads 6 are fixed inside the collar 7 and arranged symmetrically around its axis, and two curved grooves 503 are recessed on the outer wall of the thickened tube 502.

[0153] If a conventional lifting mechanism, such as an electric cylinder, electromagnet, or hydraulic cylinder, is used, the position of the ball head 6 cannot be precisely positioned, thus making it impossible to accurately adjust the rotation angle of the gear ring 501. To achieve precise adjustment of the rotation angles of the gear ring 501 and the paddle plate 2, in this embodiment, the lifting mechanism includes a fixed plate 8, a screw 9, and a servo motor 10. The fixed plate 8 is sleeved on the rotating shaft 4 below the sleeve 5, and the fixed plate 8 is fixedly connected to the rotating shaft 4. A rechargeable and replaceable battery module can be fixed on the fixed plate 8 to power the servo motor 10.

[0154] The servo motor 10 is fixedly connected to the fixed plate 8, and the vertically arranged screw 9 is connected to the output end of the servo motor 10.

[0155] The collar 7 has a threaded hole, through which the screw 9 passes and is threadedly connected. A vertically arranged guide rod 11 is fixed on the fixing plate 8, and the guide rod 11 passes through a through hole in the collar 7.

[0156] The servo motor 10 can precisely control the number of rotations, thus enabling precise adjustment of the height of the ball head 6.

[0157] The reaction process for preparing potassium sulfate using the Mannheim process is exothermic and involves high temperatures. To recover some of the excess heat energy, in this embodiment, a detachable heat exchange box is fixed to the shell 1. The rotating shaft 4 has an internal cavity, which is divided into an inlet chamber 404 and an outlet chamber 406 by a partition 403. The outer wall of the rotating shaft 4, located outside the furnace body 22, has an inlet port 405 connected to the inlet chamber 404 and an outlet port 407 connected to the outlet chamber 406. The top of the inlet chamber 404 is connected to the heat exchange box via a first connecting pipe 14, and the outlet chamber 406 is connected to the heat exchange box via a second connecting pipe 15.

[0158] The rotating shaft 4 is fitted with three sealing rings 408. The liquid inlet 405 and the liquid outlet 407 are respectively located in two interval areas formed by the three sealing rings 408. The liquid outlet collection pipe 12 and the liquid inlet collection pipe 13 are respectively fitted outside the two interval areas.

[0159] The liquid inlet collecting pipe 13 is connected to the liquid inlet 405 and is externally connected to the first liquid inlet pipe 1301; the liquid outlet collecting pipe 12 is connected to the liquid outlet 407 and is externally connected to the first liquid outlet pipe 1201. The first liquid outlet pipe 1201 is connected to the second heat transfer pipe 57 and the first liquid inlet pipe 1301 is connected to the first heat transfer pipe (55).

[0160] In order to plan the flow path of the heat transfer medium, in this embodiment, the heat exchange box adopts a first heat exchange box 16 and a second heat exchange box 17, which are respectively arranged on both sides of the rotating shaft 4. They are respectively connected to the first connecting pipe 14 and the second connecting pipe 15, and the ends of them that are away from the first connecting pipe 14 or the second connecting pipe 15 are connected through a third connecting pipe 18.

[0161] During production, the angle of paddle 2 is adjusted as follows:

[0162] During basic mixing:

[0163] A stirring drive device connected to the rotating shaft 4 via a bottom fixed flange 401 is operated, driving the rotating shaft 4 to rotate. Since the rotating shaft 4 is fixed to the housing 1 via a top fixed flange 402, the housing 1 rotates synchronously with the rotating shaft 4. The paddle 2 below the housing 1 rotates together with the housing 1, stirring the potassium sulfate material in the Mannheim furnace through the arc-shaped plate structure, thereby achieving mixing and agitation of the material.

[0164] Activate paddle angle adjustment as needed when adjusting the stirring direction or effect to match operating conditions:

[0165] Servo motor 10 starts, driving screw 9 to rotate. Because screw 9 engages with the threaded hole of collar 7, and collar 7 is limited by guide rod 11, it can only move up and down. Collar 7 moves vertically up and down along guide rod 11. Ball head 6 on the inner side of collar 7 moves up and down synchronously with collar 7, sliding within the curved groove 503 of thickened tube 502 at the bottom of sleeve 5. Because curved groove 503 is a curved structure arranged from bottom to top, the height change of ball head 6 forces thickened tube 502 and sleeve 5 to rotate relative to shaft 4. Gear ring 501 at the top of sleeve 5 rotates synchronously with sleeve 5, meshing with rack 3, causing rack 3 to slide horizontally along the protrusion 101 on the inner wall of housing 1 through groove 301.

[0166] The rack 3 meshes with the gears 202 on the top of all the paddles 2. The rack 3 slides, causing the gears 202 to rotate, which in turn drives the paddles 2 to rotate through the connecting shaft 201, thereby adjusting the angle of the paddles 2. The servo motor 10 precisely controls the number of rotations to achieve precise adjustment of the height of the ball head 6, ultimately completing the precise positioning of the angle of the paddles 2.

[0167] By adjusting the angle of paddle 2, the stirring direction and effect can be changed, making it suitable for the following different operating conditions in potassium sulfate production:

[0168] When the material has a high viscosity, such as in the middle and later stages of the reaction, the material tends to be solid or semi-solid: Adjust the angle of the paddle 2 so that its arc surface forms a large angle with the direction of rotation, close to perpendicular, to enhance the pushing and shearing force of the paddle on the material, avoid material accumulation, and ensure uniform mixing.

[0169] When the material viscosity is low, such as in the early stage of the reaction, the material is in a liquid or thin paste state: adjust the angle of the paddle 2 so that its arc surface forms a small angle with the direction of rotation, close to parallel, to reduce stirring resistance, avoid excessive splashing of material, and at the same time ensure a light mixing effect.

[0170] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. An energy storage heat exchanger, characterized in that: it comprises a cylindrical heat preservation wall (23) and a liquid storage tank (59), the heat preservation wall (23) is internally provided with three placing cavities (2301) spaced apart from top to bottom, two adjacent placing cavities (2301) are connected through a first heat exchange cavity (2303) and a second heat exchange cavity (2304), and high-temperature energy storage tanks (24), medium-temperature energy storage tanks (28) and low-temperature energy storage tanks (29) are sequentially placed in the three placing cavities (2301) from bottom to top, the high-temperature energy storage tanks (24) are filled with molten salt, and the medium-temperature energy storage tanks (28) and the low-temperature energy storage tanks (29) are filled with heat-conducting oil; the high-temperature energy storage tanks (24) are internally provided with heat exchange chambers (25), the heat exchange chambers (25) are connected through a second liquid inlet pipe (2501) and a second liquid outlet pipe (2502) penetrating to the outside of the heat preservation wall (23); the medium-temperature energy storage tanks (28) are connected through a third liquid outlet pipe (2801) and a third liquid inlet pipe (2802) penetrating to the outside of the heat preservation wall (23); the low-temperature energy storage tanks (29) are connected through a fourth liquid outlet pipe (2901) and a fourth liquid inlet pipe (2902) penetrating to the outside of the heat preservation wall (23); the first heat exchange cavity (2303) and the second heat exchange cavity (2304) are both connected through a vacuum extraction branch pipe (32) and a gas filling pipe (35) penetrating to the outside of the heat preservation wall (23), and the two vacuum extraction branch pipes (32) and the two gas filling pipes (35) are connected with a vacuum degree control system outside the heat preservation wall (23); the vacuum degree control system controls the vacuum degree in the first heat exchange cavity (2303) and the second heat exchange cavity (2304); a liquid inlet end of the liquid storage tank (59) is connected through a first return pipe (58) with the second liquid outlet pipe (2502) of the energy storage heat exchanger, a liquid outlet end of the liquid storage tank (59) is connected through a first heat transfer pipe (55) with a heat exchange tank provided in a Mannheim reaction furnace, a first conveying pump (56) is connected in series on the first heat transfer pipe (55), and the heat exchange tank in the Mannheim reaction furnace is connected through a second heat transfer pipe (57) with the second liquid inlet pipe (2501) of the energy storage heat exchanger; a tail gas pipe (2201) of the Mannheim reaction furnace is connected with a tail gas connecting pipe (48), a third three-way valve (50) is connected in series in the middle of the tail gas connecting pipe (48), a fourth three-way valve (51) is connected at the end of the tail gas connecting pipe (48), a remaining port of the third three-way valve (50) is connected through a first bypass pipe (53) with an air inlet pipe (2702) of the energy storage heat exchanger, and remaining two ports of the fourth three-way valve (51) are respectively connected with a post-treatment connecting pipe (52) and connected through a second bypass pipe (54) with an air outlet pipe (2701) of the energy storage heat exchanger. ​ The third liquid outlet pipe (2801) of the medium-temperature energy storage tank (28) is connected with the first heat supply pipe (60) in penetration, the third liquid inlet pipe (2802) of the medium-temperature energy storage tank (28) is connected with the second heat recovery pipe (62) in penetration, the first heat supply pipe (60) is connected with the second delivery pump (61) in series, and the first heat supply pipe (60) and the second heat recovery pipe (62) form a loop with the heating pipeline of the synthesis process section. The fourth liquid outlet pipe (2901) of the low-temperature energy storage tank (29) is connected with the second heat supply pipe (63) in penetration, the fourth liquid inlet pipe (2902) of the low-temperature energy storage tank (29) is connected with the third heat recovery pipe (65) in penetration, the second heat supply pipe (63) is connected with the third delivery pump (64) in series, and the second heat supply pipe (63) and the third heat recovery pipe (65) form a loop with the heating pipeline of the complex decomposition process section.

2. The energy storage type heat exchanger according to claim 1, characterized in that: both upper and lower ends of the placement cavity (2301) are provided with the placement tables (2302); the high-temperature energy storage tank (24) is provided with the annular first clamping plates (2401) on the upper and lower ends of the outer side, and the first clamping plates (2401) and the placement tables (2302) are sequentially provided with the high-temperature resistant sealing pads (30) and the sealing rings (31); the medium-temperature energy storage tank (28) is provided with the annular second clamping plates (2804) on the upper and lower ends of the outer side, and the second clamping plates (2804) and the placement tables (2302) are sequentially provided with the high-temperature resistant sealing pads (30) and the sealing rings (31); the low-temperature energy storage tank (29) is provided with the annular third clamping plates (2904) on the upper and lower ends of the outer side, and the third clamping plates (2904) and the placement tables (2302) are sequentially provided with the high-temperature resistant sealing pads (30) and the sealing rings (31).

3. The energy storage type heat exchanger according to claim 2, characterized in that: the vacuum degree control system comprises the gas filling branch pipes (36) connected with the gas filling pipes (35) in penetration, the high-pressure gas tanks (38) and the vacuum pumps (45); the gas filling branch pipes (36) are connected with the first stop valves (3601) and the pressure regulating valves (3602) in series, and the two gas filling branch pipes (36) are connected with the high-pressure gas tanks (38) in penetration through the gas filling main pipes (37); the two vacuum extraction branch pipes (32) are connected with the vacuum extraction main pipe (33) through the first three-way valves (34), the vacuum extraction main pipe (33) is connected with the gas inlet end of the vacuum pumps (45) through the gas extraction pipes (46), and the gas extraction pipes (46) are connected with the second stop valves (47) in series.

4. The energy storage type heat exchanger according to claim 3, characterized in that: the gas outlet end of the vacuum pumps (45) is connected with the gas storage tanks (41) through the gas storage tank connection pipes (42), the gas storage tank connection pipes (42) are connected with the second three-way valves (43) in series, and the remaining outlets of the second three-way valves (43) are connected with the emptying pipes (44); the gas storage tanks (41) are connected with the superchargers (39) through the supercharger connection gas pipes (40), and the superchargers (39) output the pressurized gas in the gas storage tanks (41) to the inside of the high-pressure gas tanks (38).

5. The energy storage heat exchanger according to claim 4, wherein the heat exchange chamber (25) is annular, and an electric auxiliary heating device (26) is arranged in the central through hole of the heat exchange chamber (25).

6. The energy storage heat exchanger according to claim 5, wherein the high-temperature energy storage tank (24) is internally provided with a spiral pipe (27), and the two ends of the spiral pipe (27) are respectively connected with an exhaust pipe (2701) and an air inlet pipe (2702) which are arranged outside the heat preservation wall (23), and the exhaust pipe (2701) and the air inlet pipe (2702) are connected with the tail gas pipe of the Manheim reaction furnace through valves.

7. A heating system for potassium sulfate production, comprising the energy storage heat exchanger according to claim 6, wherein the heat exchange box of the Manheim reaction furnace is fixed above the shell (1) of the stirring structure, and a rotating shaft (4) is fixed below the shell (1), the rotating shaft (4) is hollow, and the hollow space is divided into a liquid inlet cavity (404) and a liquid outlet cavity (406) by a partition plate (403), the outer wall of the rotating shaft (4) outside the furnace body (22) of the Manheim reaction furnace is provided with a liquid inlet opening (405) connected with the liquid inlet cavity (404) and a liquid outlet opening (407) connected with the liquid outlet cavity (406), the top of the liquid inlet cavity (404) is connected with the heat exchange box through a first connecting pipe (14), and the liquid outlet cavity (406) is connected with the heat exchange box through a second connecting pipe (15). The rotating shaft (4) is externally provided with three sealing snap rings (408), the liquid inlet opening (405) and the liquid outlet opening (407) are arranged in two interval regions formed by the three sealing snap rings (408), respectively, and the liquid outlet collecting pipe (12) and the liquid inlet collecting pipe (13) are respectively arranged outside the two interval regions. The liquid inlet collecting pipe (13) is connected with the liquid inlet opening (405), and the outside is connected with a first liquid inlet pipe (1301). The liquid outlet collecting pipe (12) is connected with the liquid outlet opening (407), and the outside is connected with a first liquid outlet pipe (1201). The first liquid outlet pipe (1201) is connected with the second heat transfer pipe (57), and the first liquid inlet pipe (1301) is connected with the first heat transfer pipe (55).

8. The heating system for potassium sulfate production according to claim 7, wherein the bottom surface of the reaction chamber (19) in the Manheim reaction furnace is planar, a feeding pipe (1901) is connected above the reaction chamber (19), a discharging pipe (1903) is connected outside the bottom surface of the reaction chamber (19) and arranged downward, and the stirring structure is arranged inside the reaction chamber (19). The stirring structure comprises a long strip-shaped shell (1), a paddle (2) and a control driving assembly. A plurality of interval arranged paddles (2) are rotationally arranged below the shell (1). The control driving assembly comprises a rotating shaft (4) and a control component, the rotating shaft (4) is fixedly connected with the shell (1), and the control component is used for adjusting the angle of the paddle (2).

9. The heating system for potassium sulfate production according to claim 8, wherein ​ ​ ​ ​ The regulating assembly comprises a rack (3), a sleeve (5) and a rotary driving device; The paddle (2) is fixedly connected with a gear (202) at the top through a connecting shaft (201), the gear (202) is arranged in the housing (1), the rack (3) is slidably arranged in the housing (1), and the rack (3) is in meshing connection with all the gears (202). The sleeve (5) is sleeved on the rotating shaft (4), the top of the sleeve (5) penetrates into the housing (1) and is fixedly connected with a gear ring (501), and the gear ring (501) is in meshing connection with the rack (3). The rotary driving device is used for driving the sleeve (5) to rotate relative to the rotating shaft (4).

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