Solar high-temperature air calcining carbide slag system and method

Abstract

The invention discloses a solar high-temperature air calcining carbide slag system and method. The system comprises a tower type solar heat absorber, a heat exchanger, a heat storage tank and a suspension calcining carbide slag unit, the tower type solar heat absorber is connected with the heat side of the heat exchanger to form a heat absorption circulation loop; the heat absorption working medium absorbs heat in the tower type solar heat absorber and releases heat on the heat side of the heat exchanger; the heat storage tank is connected with the cold side of the heat exchanger to form a heat storage circulation loop; the heat storage air absorbs heat in the cold side of the heat exchanger and releases heat in the heat storage tank; the heat storage tank absorbs and stores the heat of the heat storage air; the heat storage tank is connected with the carbide slag suspension calcination unit to form a heat release circulation loop; the heat release air absorbs heat in the heat storage tank and releases heat in the carbide slag suspension calcination unit to decompose carbide slag. Large-enthalpy-difference heat extraction is carried out through the pressurized gas, and the advantages of being good in temperature uniformity and small in thermal stress are achieved; meanwhile, clean solar photo-thermal is used for replacing fossil fuel to provide heat for calcining the carbide slag, so that energy is saved, and consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of photothermal utilization, heat storage and comprehensive utilization of carbide slag waste resources, and relates to a carbide slag processing system, and in particular to a solar high-temperature air calcination carbide slag system and method. Background Art

[0002] With the continuous development of the chlor-alkali industry, the emission and stockpile of carbide slag are increasing. At present, most of the treatment methods of carbide slag are still discarded, piled up and landfilled, which has caused serious environmental pollution and waste of calcium resources. As a calcium-containing resource, carbide slag is mainly composed of calcium hydroxide (content of more than 80%), which can be used to prepare calcium oxide products after drying and calcination. In the existing carbide slag calcination process, hot blast furnaces and high-temperature calcining furnaces with burners in the middle and lower parts are generally used for calcination, which will consume a large amount of fossil fuels and is not conducive to the realization of energy conservation and carbon reduction goals. The use of low-carbon fuels and renewable energy as heat supply can effectively improve the carbon emission reduction capacity of carbide slag calcination.

[0003] Solar energy resources are abundant, clean and pollution-free, and are widely concerned about renewable energy. Using solar energy to heat carbide slag to provide energy is an effective measure to reduce carbon emissions in the calcium oxide product industry. The existing common solar energy heating methods mainly include traditional water / steam absorbers, molten salt absorbers, and air chamber absorbers. However, the above absorbers all have their own limitations. Water / steam absorbers are prone to overheating and bursting in the high-temperature steam section; molten salt absorbers will produce molten salt decomposition and serious corrosion problems under high temperature conditions exceeding 700°C, which is not suitable for the temperature range used for carbide slag calcination; cavity air absorbers are prone to local overheating and failure due to uneven flow. In addition, affected by factors such as weather and day and night changes, the instability and intermittency of solar energy also limit its development to a certain extent. Therefore, in order to make full use of solar energy and minimize carbon emissions from carbide slag calcination, it is urgent to develop a photothermal utilization technology that uses solar energy to heat and calcine carbide slag. Summary of the invention

[0004] The present invention provides a solar high-temperature air calcining carbide slag system and method to overcome the defects of the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a tower solar high-temperature air calcining carbide slag system, comprising a tower solar heat absorber, a heat exchanger, a heat storage tank and a suspended calcining carbide slag unit; the tower solar heat absorber is connected to the hot side of the heat exchanger to form a heat absorption circulation loop, and the heat-absorbing working medium circulates in the heat absorption circulation loop; the heat-absorbing working medium absorbs heat in the tower solar heat absorber and releases heat in the hot side of the heat exchanger; the heat storage tank is connected to the cold side of the heat exchanger to form a heat storage circulation loop, and the heat storage air circulates in the heat storage circulation loop; the heat storage air absorbs heat in the cold side of the heat exchanger and releases heat in the heat storage tank; the heat storage medium in the heat storage tank absorbs the heat of the heat storage air and stores it; the heat storage tank is connected to the suspended calcining carbide slag unit to form a heat release circulation loop, and the heat release air circulates in the heat release circulation loop; the heat release air absorbs heat in the heat storage tank and releases heat in the suspended calcining carbide slag unit; the suspended calcining carbide slag unit decomposes the carbide slag using the heat of the heat release air.

[0007] Furthermore, the system also includes a cooling water tower and a water-cooled heat exchanger; the hot side of the water-cooled heat exchanger is arranged in the heat absorption circulation loop, and is connected between the hot side of the heat exchanger and the tower-type solar thermal absorber along the flow direction of the heat absorption medium; if the temperature of the heat absorption medium exceeds a threshold value, heat is released again in the hot side of the water-cooled heat exchanger; the cooling water tower and the cold side of the water-cooled heat exchanger are connected to form a cooling circulation loop, and the cooling medium circulates in the cooling circulation loop; the cooling medium absorbs heat in the cold side of the water-cooled heat exchanger.

[0008] Furthermore, the system also includes a first centrifugal water pump, a second centrifugal water pump, an air storage tank, a first variable frequency boost compressor and a second variable frequency boost compressor; the first centrifugal water pump and the second centrifugal water pump are arranged in parallel in the cooling circulation loop, and are connected between the cooling water tower and the cold side of the water-cooled heat exchanger along the flow direction of the cooling medium; the first variable frequency boost compressor and the second variable frequency boost compressor are arranged in parallel; the air storage tank and the first variable frequency boost compressor and the second variable frequency boost compressor are connected in sequence in the heat absorption circulation loop along the flow direction of the heat absorption medium, and are arranged between the hot side of the water-cooled heat exchanger and the tower solar thermal absorber.

[0009] Furthermore, the heat storage tank is a double-layer heat storage tank, including an inner tank and an outer tank nested with each other, and both the inner tank and the outer tank are filled with solid particles; the inner tank and the outer tank of the heat storage tank are arranged in parallel in the heat storage circulation loop and the heat release circulation loop; the inner tank and the outer tank store heat and release heat respectively at the same time, and the heat storage and heat release are operated alternately in the inner tank and the outer tank.

[0010] Furthermore, the system also includes a first cyclone separator, a first high-temperature variable frequency fan, a second cyclone separator and a second high-temperature variable frequency fan; the first cyclone separator and the first high-temperature variable frequency fan are sequentially connected in the heat storage circulation loop along the flow direction of the heat storage air, and are arranged between the heat storage tank and the cold side of the heat exchanger; the second cyclone separator and the second high-temperature variable frequency fan are both arranged in the heat release circulation loop, along the flow direction of the heat release air, the second cyclone separator is connected between the heat storage tank and the suspended calcined carbide slag unit, and the second high-temperature variable frequency fan is connected between the suspended calcined carbide slag unit and the heat storage tank.

[0011] Furthermore, the suspended calcined carbide slag unit includes a decomposition furnace, a separation cyclone and a preheating subunit; the decomposition furnace, the separation cyclone and the preheating subunit are sequentially connected in the heat release circulation loop along the flow direction of the heat release air; the heat storage tank is connected to the decomposition furnace, the heat release air from the heat storage tank enters the decomposition furnace to decompose the carbide slag, and the decomposition products are discharged to the separation cyclone together with the heat release air; the separation cyclone separates the heat release air from the decomposition products; the separated heat release air preheats the carbide slag before decomposition in the preheating subunit, the preheating subunit is connected to the heat storage tank, and the preheated heat release air enters the heat storage tank again.

[0012] Furthermore, the suspended calcined carbide slag unit also includes a carbide slag hopper, a drying crusher, a purification and impurity removal separator, a cooling subunit and a finished product silo; the carbide slag hopper, the drying crusher, the purification and impurity removal separator, the preheating subunit and the decomposition furnace are connected in sequence to form a feeding path; the purification and impurity removal separator is used to separate impurities in the carbide slag; the decomposition furnace, the separation cyclone, the cooling subunit and the finished product silo are connected in sequence to form a discharging path; the cooling subunit is used to cool the decomposition products separated by the separation cyclone; the drying crusher is also arranged in the heat release circulation loop, connected between the preheating subunit and the heat storage tank along the flow direction of the heat release air; a third cyclone separator is also provided between the drying crusher and the heat storage tank.

[0013] Furthermore, the preheating subunit is a multi-stage preheating subunit, including multiple preheating cyclones; the upper part of the preheating cyclone is provided with a carbide slag inlet and a heat-releasing air inlet along the tangent direction of the cylinder, a heat-releasing air outlet is provided in the vertical direction of the top, and a carbide slag outlet is provided at the bottom; the first-stage preheating cyclone to the last-stage preheating cyclone are arranged in a left-right staggered manner from top to bottom; the carbide slag inlet of the first-stage preheating cyclone is connected to the purification and impurity removal separator; the heat-releasing air inlet of the last-stage preheating cyclone is connected to the separation cyclone; the carbide slag outlet of the last-stage preheating cyclone is connected to the decomposition furnace; the heat-releasing air outlet of the first-stage preheating cyclone is connected to the drying crusher.

[0014] Furthermore, the cooling subunit is a multi-stage cooling subunit, including multiple cooling cyclones; the upper part of the cooling cyclone is provided with a decomposition product inlet and an air inlet along the tangential direction of the cylinder, the top is provided with an air outlet in the vertical direction, and the bottom is provided with a decomposition product outlet; the first-stage cooling cyclone to the last-stage cooling cyclone are arranged in a left-right staggered manner from top to bottom; the decomposition product inlet of the first-stage cooling cyclone is connected to the separation cyclone; the air inlet of the last-stage cooling cyclone directly allows air to enter; the decomposition product outlet of the last-stage cooling cyclone is connected to the finished product silo; the air outlet of the first-stage cooling cyclone is directly discharged to the outside.

[0015] In a second aspect, the present invention provides a tower-type solar high-temperature air calcination method for carbide slag, which is realized by the tower-type solar high-temperature air calcination system for carbide slag, including a heat absorption cycle, a heat storage cycle, a heat release cycle and calcination of carbide slag;

[0016] The working mode of the heat absorption cycle is as follows: the sunlight is reflected and concentrated to the tower solar thermal absorber through the heliostat field to make it absorb heat; the heat absorbing medium is gas; the gas enters the tower solar thermal absorber to absorb heat; the tower solar thermal absorber produces heated gas, which enters the hot side of the heat exchanger and exchanges heat with the heat storage air of the heat storage cycle to cool down, and then enters the hot side of the water-cooled heat exchanger, and finally is re-delivered to the tower solar thermal absorber to absorb heat; the heat absorption cycle is repeated; wherein, if the temperature of the gas cooled down after the heat exchange exceeds the threshold value, it exchanges heat with the cooling water of the auxiliary cooling cycle in the hot side of the water-cooled heat exchanger, and is further cooled down to below the threshold value before being re-delivered to the tower solar thermal absorber to absorb heat; if the temperature of the cooled gas does not exceed the threshold value, it is directly re-delivered to the tower solar thermal absorber to absorb heat; the working mode of the auxiliary cooling cycle is as follows: the cooling water in the cooling water tower is transported to the water-cooled heat exchanger to exchange heat with the gas in the heat absorption cycle to reduce the temperature of the gas, and the cooling water after the heat exchange re-enters the cooling water tower, and the auxiliary cooling cycle is repeated;

[0017] The working mode of the heat storage cycle is as follows: the heat storage air is input into the cold side of the heat exchanger, and is heated after exchanging heat with the gas in the heat absorption cycle; the heated heat storage air enters the inner tank or outer tank of the heat storage tank, heats the solid particles, and the solid particles absorb the heat carried by the heat storage air and store it; then the heat storage air is discharged from the inner tank or outer tank of the heat storage tank and re-input into the heat exchanger, thereby repeating the heat storage cycle;

[0018] The working mode of the heat release cycle is as follows: the heat release air is input into the inner tank or outer tank of the heat storage tank, and is heated by the heat stored solid particles; then the heated heat storage air is discharged from the inner tank or outer tank of the heat storage tank, enters the suspended calcined carbide slag unit to release heat and calcine the carbide slag, and finally is re-input into the inner tank or outer tank of the heat storage tank to absorb heat, thereby repeating the heat release cycle;

[0019] The inner tank and the outer tank of the heat storage tank store heat and release heat respectively at the same time, and the heat storage and heat release are performed alternately in the inner tank and the outer tank.

[0020] The beneficial effect of the present invention is that the present invention combines tower solar thermal technology, solid particle heat storage technology and calcined carbide slag technology. The tower solar thermal absorber generates high-temperature gas above 900°C and stores heat in the heat storage tank. When releasing heat, the air absorbs heat from the solid particles and enters the decomposition furnace to calcine the carbide slag. Specifically, firstly, the system uses pressurized gas to extract heat with a large enthalpy difference, and has the advantages of good temperature uniformity and small thermal stress. Secondly, the decomposition furnace in the traditional calcined carbide slag process needs to use a large amount of coal powder, which not only consumes a large amount of fossil energy, but also causes environmental pollution and a large amount of carbon emissions. Compared with the traditional calcination process, the present invention uses clean solar thermal instead of fossil fuels to provide heat for calcined carbide slag, while saving energy and reducing consumption, achieving zero carbon emissions, and has the characteristics of high efficiency, energy saving, cleanness and low carbon. In addition, the present invention combines tower solar thermal absorption technology and solid particle heat storage technology to achieve efficient thermal utilization of solar energy. The combination of heat absorption and heat storage can effectively solve the problems of volatility and intermittency of solar energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a tower type solar high temperature air calcining carbide slag system and method;

[0022] Figure 2 is a schematic diagram of the heat storage tank 31 and the pipeline;

[0023] The markings in the attached drawings are: 11, heliostat field; 12, tower solar thermal absorber; 13, heat exchanger; 14, gas storage tank; 151, first variable frequency booster compressor; 152, second variable frequency booster compressor; 21, cooling water tower; 22, water-cooled heat exchanger; 231, first centrifugal water pump; 232, second centrifugal water pump; 31, heat storage tank; 311, inner tank; 312, outer tank; 32, first cyclone separator; 33, first high temperature variable frequency fan; 34, second cyclone separator; 35, second high temperature variable frequency fan; 41, decomposition furnace; 42, separation cyclone; 43, preheating subunit; 44, carbide slag hopper; 45, drying crusher; 46, purification and impurity removal separator; 47, cooling subunit; 48, finished product silo; 49, third cyclone separator. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, the present invention provides a tower type solar high temperature air calcining carbide slag system, comprising a tower type solar heat absorber 12, a heat exchanger 13, a heat storage tank 31 and a suspended calcining carbide slag unit.

[0026] The tower solar thermal absorber 12 is arranged on the reflected light path of the heliostat field 11. The tower solar thermal absorber 12 is connected to the hot side of the heat exchanger 13 to form a heat absorption circulation loop, and the heat absorbing medium circulates in the heat absorption circulation loop. The heat absorbing medium absorbs heat in the tower solar thermal absorber 12 and releases heat in the hot side of the heat exchanger 13.

[0027] Among them, the tower solar thermal absorber 12 uses pressurized gas as the heat absorbing medium, such as air, nitrogen, helium, etc. The tower solar thermal absorber 12 adopts the indirect heat transfer method of "metal bath", and is filled with liquid metal or alloy inside, which evenly transfers the heat of high heat flux density to the spiral winding, and then is taken away by the heat absorbing medium in the spiral winding. It has the characteristics of high thermal conductivity and uniform temperature, can achieve efficient heat transfer, and even out the heat flux density, reduce thermal stress, and avoid hazards such as pipe burst. The tower solar thermal absorber 12 can specifically be a tower solar cyclone absorber (CN116428754A), which uses gas to extract heat with a large enthalpy difference. On the one hand, it can reach a high temperature of more than 900°C, which is perfectly adapted to the temperature range of calcium carbide slag calcination. On the other hand, the good temperature uniformity of the absorber can avoid pipe bursts, local overheating, etc.

[0028] The heat exchanger 13 is a finned tube heat exchanger 13, which can be used under large temperature difference conditions. Finned tubes are used to enhance heat transfer, and the U-shaped tube connections at both ends can expand freely to reduce the thermal stress caused by the large temperature difference. The tube side is the hot side, and the heat absorbing medium flows in the tube side. The shell side is the cold side, and the heat storage air flows in the shell side.

[0029] In a preferred embodiment, the system further includes a cooling water tower 21 and a water-cooled heat exchanger 22. The hot side of the water-cooled heat exchanger 22 is arranged in a heat absorption circulation loop, and is connected between the hot side of the heat exchanger 13 and the tower-type solar thermal absorber 12 along the flow direction of the heat absorbing medium. If the temperature of the heat absorbing medium exceeds a threshold value, heat is released again in the hot side of the water-cooled heat exchanger 22. The cooling water tower 21 and the cold side of the water-cooled heat exchanger 22 are connected to form a cooling circulation loop, and the cooling medium circulates in the cooling circulation loop. The cooling medium absorbs heat in the cold side of the water-cooled heat exchanger 22.

[0030] The water-cooled heat exchanger 22 is a coiled tube heat exchanger 13, and the tube side can withstand high pressure. The tube side is the hot side, and the heat absorbing medium flows in the tube side. The shell side is the cold side, and the cooling medium flows in the shell side.

[0031] Specifically, the system also includes a first centrifugal water pump 231 and a second centrifugal water pump 232. The first centrifugal water pump 231 and the second centrifugal water pump 232 are arranged in parallel in the cooling cycle, and are connected between the cooling water tower 21 and the cold side of the water-cooled heat exchanger 22 along the flow direction of the cooling medium. The first centrifugal water pump 231 and the second centrifugal water pump 232 adopt a parallel double pipeline with one in use and one in reserve. Under normal circumstances, only one is enabled to participate in the cooling cycle. Once damage occurs during operation, it is immediately switched to another spare pipeline. In the heat absorption cycle, the temperature of the hot side outlet of the heat exchanger 13 will gradually increase. When the temperature monitored by the hot side outlet temperature indicator of the heat exchanger 13 exceeds the threshold, the cooling cycle is started.

[0032] The system also includes an air storage tank 14, a first variable frequency boost compressor 151 and a second variable frequency boost compressor 152. The first variable frequency boost compressor 151 and the second variable frequency boost compressor 152 are arranged in parallel. The air storage tank 14 and the first variable frequency boost compressor 151 and the second variable frequency boost compressor 152 are sequentially connected in the heat absorption circulation loop along the flow direction of the heat absorbing working medium, and are arranged between the hot side of the water-cooled heat exchanger 22 and the tower solar thermal absorber 12. Among them, the first variable frequency boost compressor 151 and the second variable frequency boost compressor 152 are used to overcome the pipeline pressure drop to meet the inlet pressure requirement of the tower solar thermal absorber 12. Because the fan is easily damaged in a high temperature environment, a parallel double pipeline with one in use and one in reserve is adopted. Under normal circumstances, only one pipeline is enabled to participate in the heat absorption cycle. Once damage occurs during operation, it is immediately switched to another spare pipeline.

[0033] The heat storage tank 31 is connected to the cold side of the heat exchanger 13 to form a heat storage circulation loop, and the heat storage air circulates in the heat storage circulation loop. The heat storage air absorbs heat in the cold side of the heat exchanger 13 and releases heat in the heat storage tank 31. The heat storage medium in the heat storage tank 31 absorbs the heat of the heat storage air and stores it.

[0034] The heat storage tank 31 is connected to the suspension calcined carbide slag unit to form a heat release circulation loop, in which the heat release air circulates. The heat release air absorbs heat in the heat storage tank 31 and releases heat in the suspension calcined carbide slag unit. The suspension calcined carbide slag unit uses the heat of the heat release air to decompose the carbide slag.

[0035] Specifically, Figure 2As shown, the heat storage tank 31 is a double-layer heat storage tank, which adopts a sleeve-type double-tank structure with one charge and one discharge, including an inner tank 311 and an outer tank 312 nested with each other, and the inner tank 311 and the outer tank 312 are filled with solid particles. The solid particles can be a variety of particle materials such as quartz, pebbles, ceramics, etc. The inner tank 311 and the outer tank 312 of the heat storage tank 31 are arranged in parallel in the heat storage circulation loop and the heat release circulation loop. That is, in the heat storage circulation loop, the inner tank 311 and the outer tank 312 are both connected to the cold side of the heat exchanger 13; in the heat release circulation loop, the inner tank 311 and the outer tank 312 are both connected to the suspended calcined calcium carbide slag unit. The inner tank 311 and the outer tank 312 store heat and release heat at the same time, respectively, and the heat storage and heat release are alternately operated in the inner tank 311 and the outer tank 312. That is, the inner tank 311 releases heat while the outer tank 312 stores heat, and then the outer tank 312 releases heat and the inner tank 311 stores heat, and this alternating operation is repeated, thereby improving the heat utilization efficiency.

[0036] According to the heat storage principle of the thermocline layer, in the heat storage cycle, the heat storage air enters the heat storage tank 31 from the top and heats the quartz particles. The bottom outlet temperature is first kept at a low temperature, then gradually increases, and finally kept at a high temperature. At this time, the heat storage is completed. Specifically, the outer tank 312 is provided with a first inlet and a fourth outlet at the top, and a first outlet and a fourth inlet at the bottom. The inner tank 311 is provided with a second inlet and a third outlet at the top, and a second outlet and a third inlet at the bottom. The first and second inlet pipelines at the top are provided with a first and second valve, and the third and fourth outlet pipelines are provided with a seventh and eighth valve. The first and second outlet pipelines at the bottom are provided with a third and fourth valve, and the third and fourth inlet pipelines are provided with a fifth and sixth valve. When the outer tank 312 stores heat, the first and third valves are opened, and the second and fourth valves are closed. When the inner tank 311 stores heat, the second and fourth valves are opened, and the first and third valves are closed. When the outer tank 312 releases heat, the sixth and eighth valves are opened, and the fifth and seventh valves are closed. When the inner tank 311 releases heat, the fifth and seventh valves are opened, and the sixth and eighth valves are closed.

[0037] During the heat storage process, the heat storage air enters from the top and exits from the bottom. During the heat release process, the heat release air enters from the bottom and exits from the top. The double tanks can realize one charging and one releasing, and the two tanks are charged and released alternately. For example, during heat storage, the heat storage air enters from the first inlet at the top of the outer tank 312 and is discharged from the first outlet at the bottom of the outer tank 312. After the outer tank 312 completes heat storage, it starts to release heat. The heat release air enters from the fourth inlet at the bottom of the outer tank 312 and is discharged from the fourth outlet at the top of the outer tank 312. While the outer tank 312 is releasing heat, the heat storage pipeline is switched by opening and closing the valve, and the inner tank 311 starts to store heat. The heat storage air enters from the second inlet at the top of the inner tank 311 and is discharged from the second outlet at the bottom of the inner tank 311. After the outer tank 312 completes heat release, the pipeline is switched to the inner tank 311 to release heat, and the outer tank 312 stores heat again, and the heat is charged and released alternately in this way.

[0038] Specifically, the system includes a first cyclone separator 32, a first high-temperature variable frequency fan 33, a second cyclone separator 34 and a second high-temperature variable frequency fan 35. The first cyclone separator 32 and the first high-temperature variable frequency fan 33 are sequentially connected in the heat storage circulation loop along the flow direction of the heat storage air, and are arranged between the heat storage tank 31 and the cold side of the heat exchanger 13. The second cyclone separator 34 and the second high-temperature variable frequency fan 35 are both arranged in the heat release circulation loop. Along the flow direction of the heat release air, the second cyclone separator 34 is connected between the heat storage tank 31 and the suspended calcined carbide slag unit, and the second high-temperature variable frequency fan 35 is connected between the suspended calcined carbide slag unit and the heat storage tank 31. Among them, the first high-temperature variable frequency fan 33 can automatically adjust the flow rate. As the heat storage cycle proceeds, the outlet temperature of the heat storage tank 31 will change accordingly. The temperature indicator at the outlet monitors the temperature in real time and automatically adjusts the flow rate of the first high-temperature variable frequency fan 33 to achieve dynamic thermal balance.

[0039] The suspended calcined carbide slag unit includes a decomposition furnace 41, a separation cyclone 42 and a preheating subunit 43. The decomposition furnace 41, the separation cyclone 42 and the preheating subunit 43 are sequentially connected in a heat release circulation loop along the flow direction of the heat release air. The heat storage tank 31 is connected to the decomposition furnace 41, and the heat release air from the heat storage tank 31 enters the decomposition furnace 41 to decompose the carbide slag, and the decomposition products are discharged to the separation cyclone 42 together with the heat release air. The separation cyclone 42 separates the heat release air from the decomposition products. The separated heat release air preheats the carbide slag before decomposition in the preheating subunit 43, and the preheating subunit 43 is connected to the heat storage tank 31, and the preheated heat release air enters the heat storage tank 31 again to absorb heat.

[0040] Specifically, the suspended calcined carbide slag unit also includes a carbide slag hopper 44, a drying crusher 45, a purification and impurity removal separator 46, a cooling subunit 47 and a finished product silo 48. The carbide slag hopper 44, the drying crusher 45, the purification and impurity removal separator 46, the preheating subunit 43 and the decomposition furnace 41 are connected in sequence to form a feeding path. The purification and impurity removal separator 46 is used to separate the impurities silicon dioxide, aluminum oxide, iron oxide and silicate minerals in the carbide slag material to increase the percentage of calcium content in the carbide slag, and the impurities are discharged to the outside. The decomposition furnace 41, the separation cyclone 42, the cooling subunit 47 and the finished product silo 48 are connected in sequence to form a discharging path. The cooling subunit 47 is used to cool the decomposition products separated by the separation cyclone 42. The drying crusher 45 is also arranged in the heat release circulation loop, and is connected between the preheating subunit 43 and the heat storage tank 31 along the flow direction of the heat release air. A third cyclone separator 49 is also provided between the drying crusher 45 and the heat storage tank 31 .

[0041] The preheating subunit 43 is a multi-stage preheating subunit 43, including a plurality of preheating cyclones. A carbide slag inlet and a heat-releasing air inlet are provided at the upper part of the preheating cyclone along the tangent direction of the cylinder, a heat-releasing air outlet is provided at the top vertically, and a carbide slag outlet is provided at the bottom. The first-stage preheating cyclone to the last-stage preheating cyclone are arranged in a left-right staggered manner from top to bottom. The carbide slag inlet of the N-stage preheating cyclone is connected to the carbide slag outlet of the N-1-stage preheating cyclone, and the heat-releasing air inlet of the N-stage preheating cyclone is connected to the heat-releasing air outlet of the N+1-stage preheating cyclone. The carbide slag inlet of the first-stage preheating cyclone is connected to the purification and impurity removal separator 46. The heat-releasing air inlet of the last-stage preheating cyclone is connected to the separation cyclone 42. The carbide slag outlet of the last-stage preheating cyclone is connected to the decomposition furnace 41. The heat-releasing air outlet of the first-stage preheating cyclone is connected to the drying crusher 45.

[0042] The cooling subunit 47 is a multi-stage cooling subunit 47, including multiple cooling cyclones. The upper part of the cooling cyclone is provided with a decomposition product inlet and an air inlet along the tangent direction of the cylinder, an air outlet is provided in the vertical direction of the top, and a decomposition product outlet is provided at the bottom. The first-stage cooling cyclone to the last-stage cooling cyclone are arranged in a left-right staggered manner from top to bottom. The decomposition product inlet of the N-stage cooling cyclone is connected to the decomposition product outlet of the N-1-stage cooling cyclone, and the air inlet of the N-stage cooling cyclone is connected to the air outlet of the N+1-stage cooling cyclone. The decomposition product inlet of the first-stage cooling cyclone is connected to the separation cyclone 42. The air inlet of the last-stage cooling cyclone directly allows air to enter. The decomposition product outlet of the last-stage cooling cyclone is connected to the finished product bin 48. The air outlet of the first-stage cooling cyclone is directly discharged to the outside.

[0043] In summary, the specific connection relationship between each loop and path is:

[0044] Heat absorption circulation loop: the outlet of the tower solar thermal absorber 12 is connected to the hot side inlet of the heat exchanger 13, the hot side outlet of the heat exchanger 13 is connected to the hot side inlet of the water-cooled heat exchanger 22, the hot side outlet of the water-cooled heat exchanger 22 is connected to the inlet of the air storage tank 14, the outlet of the air storage tank 14 is connected to the inlets of the first variable frequency booster compressor 151 and the second variable frequency booster compressor 152 in parallel, and the outlets of the first variable frequency booster compressor 151 and the second variable frequency booster compressor 152 in parallel are connected to the inlet of the tower solar thermal absorber 12.

[0045] Cooling circulation loop: the outlet of the cooling water tower 21 is connected to the inlet of the first centrifugal water pump 231 and the second centrifugal water pump 232 in parallel, the outlet of the first centrifugal water pump 231 and the second centrifugal water pump 232 in parallel is connected to the cold side inlet of the water-cooled heat exchanger 22, and the cold side outlet of the water-cooled heat exchanger 22 is connected to the inlet of the cooling water tower 21.

[0046] Heat storage circulation loop: the outlet of the first high-temperature variable-frequency fan 33 is connected to the cold-side inlet of the heat exchanger 13, the cold-side outlet of the heat exchanger 13 is connected to the first inlet and the second inlet in parallel of the heat storage tank 31, the first outlet and the second outlet in parallel of the heat storage tank 31 are connected to the inlet of the first cyclone separator 32, and the outlet of the first cyclone separator 32 is connected to the inlet of the first high-temperature variable-frequency fan 33.

[0047] Heat release circulation loop: the outlet of the second high-temperature variable-frequency fan 35 is connected to the third inlet and the fourth inlet of the heat storage tank 31 in parallel, the third outlet and the fourth outlet of the heat storage tank 31 in parallel are connected to the inlet of the second cyclone separator 34, the outlet of the second cyclone separator 34 is connected to the gas inlet of the decomposition furnace 41, the mixed outlet of the decomposition furnace 41 is connected to the inlet of the separation cyclone cylinder 42, the gas outlet of the separation cyclone cylinder 42 is connected to the heat-releasing air inlet of the third-stage preheating cyclone cylinder of the preheating subunit 43, the heat-releasing air outlet of the first-stage preheating cyclone cylinder of the preheating subunit 43 is connected to the gas inlet of the drying crusher 45, the gas outlet of the drying crusher 45 is connected to the inlet of the third cyclone separator 49, and the outlet of the third cyclone separator 49 is connected to the inlet of the second high-temperature variable-frequency fan 35.

[0048] Feeding path: the outlet of the carbide slag hopper 44 is connected to the solid inlet of the drying crusher 45, the solid outlet of the drying crusher 45 is connected to the inlet of the purification and impurity removal separator 46, the outlet of the purification and impurity removal separator 46 is connected to the carbide slag inlet of the first-stage preheating cyclone of the preheating subunit 43, and the carbide slag outlet of the third-stage preheating cyclone of the preheating subunit 43 is connected to the solid inlet of the decomposition furnace 41.

[0049] Discharge path: the mixed outlet of the decomposition furnace 41 is connected to the inlet of the separation cyclone 42, the solid outlet of the separation cyclone 42 is connected to the decomposition product inlet of the first-stage cooling cyclone of the cooling subunit 47, and the decomposition product outlet of the third-stage cooling cyclone of the cooling subunit 47 is connected to the finished product silo 48.

[0050] The tower type solar high temperature air calcining carbide slag method comprises a heat absorption cycle, a heat storage cycle, a heat release cycle and calcining carbide slag. The cooling medium is cooling water.

[0051] The heat absorption cycle is realized through the heat absorption cycle loop, and the working mode is: the sunlight is reflected and concentrated to the tower solar thermal absorber 12 through the heliostat field 11 to absorb heat. The heat absorbing medium is gas. The gas storage tank 14 outputs gas of a certain pressure, and the gas pressure is increased to the inlet pressure required by the tower solar thermal absorber 12 by the first variable frequency booster compressor 151 or the second variable frequency booster compressor 152, and the high-pressure gas enters the tower solar thermal absorber 12 to absorb heat. The tower solar thermal absorber 12 produces high-temperature (950℃) high-pressure gas, enters the hot side of the heat exchanger 13, exchanges heat with the heat storage air of the heat storage cycle, and then cools down, and then enters the hot side of the water-cooled heat exchanger 22, and finally enters the gas storage tank 14, and then re-pressurized by the first variable frequency booster compressor 151 or the second variable frequency booster compressor 152 and transported to the tower solar thermal absorber 12 to absorb heat. In this way, the heat absorption cycle is repeated.

[0052] Among them, if the temperature of the gas cooled down after heat exchange in the heat exchanger 13 exceeds the threshold, that is, the upper temperature limit of the gas storage tank 14 (200°C), it will exchange heat with the cooling water (cooling medium) of the auxiliary cooling cycle in the hot side of the water-cooled heat exchanger 22, and further cool down to below the threshold before entering the gas storage tank 14; if the temperature of the cooled gas does not exceed the threshold, it will directly enter the gas storage tank 14.

[0053] The auxiliary cooling cycle is realized through a cooling cycle loop, and the working mode is as follows: when the outlet temperature of the hot side of the heat exchanger 13 during the heat absorption cycle exceeds the threshold value of 200°C, the auxiliary cooling cycle is started. The cooling water in the cooling water tower 21 enters the first centrifugal water pump 231 or the second centrifugal water pump 232, and is transported to the water-cooled heat exchanger 22 through the first centrifugal water pump 231 or the second centrifugal water pump 232 to exchange heat with the gas in the heat absorption cycle, thereby reducing the temperature of the gas. After the heat exchange, the cooling water re-enters the cooling water tower, thereby repeating the auxiliary cooling cycle.

[0054] The heat storage cycle is realized through a heat storage cycle loop, and the working method is as follows: the first high-temperature variable frequency fan 33 inputs the heat storage air into the cold side of the heat exchanger 13, and heats it to 935°C after heat exchange with the gas in the heat absorption cycle. The heated heat storage air enters the inner tank 311 or the outer tank 312 of the heat storage tank 31, heats the solid particles to 905°C, and the solid particles absorb the heat carried by the heat storage air and store it. Then the heat storage air is discharged from the inner tank 311 or the outer tank 312 of the heat storage tank 31, and after gas-solid separation by the first cyclone separator 32, the clean heat storage air is re-input into the cold side of the heat exchanger 13 through the first high-temperature variable frequency fan 33, so as to repeat the heat storage cycle.

[0055] The heat release cycle is realized through a heat release circulation loop, and the working mode is as follows: the second high-temperature variable frequency fan 35 inputs the heat release air into the inner tank 311 or the outer tank 312 of the heat storage tank 31, and is heated to 890°C by the high-temperature (905°C) solid particles after heat storage. Then the heated heat storage air is discharged from the inner tank 311 or the outer tank 312 of the heat storage tank 31, and after gas-solid separation by the second cyclone separator 34, enters the decomposition furnace 41 to heat and calcine the calcium carbide slag in the decomposition furnace 41. Then the heat release air is discharged from the decomposition furnace 41 together with the decomposition product, and enters the separation cyclone 42 for gas-solid separation. The separated heat-releasing air enters the preheating subunit 43 as a preheating heat source, and then enters the drying crusher 45 as a drying heat source. The drying flue gas temperature is about 200°C. Finally, after gas-solid separation by the third cyclone separator 49, the clean heat-releasing air is re-input into the inner tank 311 or the outer tank 312 of the heat storage tank 31 through the second high-temperature variable frequency fan 35 to absorb heat, thereby repeating the heat release cycle.

[0056] The inner tank 311 and the outer tank 312 of the heat storage tank 31 respectively store heat and release heat at the same time, and the heat storage and heat release are performed alternately in the inner tank 311 and the outer tank 312 .

[0057] The calcination of carbide slag is achieved through a feeding path and a discharging path, and the working method is as follows: the carbide slag hopper 44 transports the wet carbide slag to the drying crusher 45 for crushing, and is dried by the heat-releasing air in the heat-releasing cycle. Then it is transported to the purification and impurity removal separator 46 to separate impurities. The carbide slag after impurities removal enters the preheating subunit 43 to be preheated by the heat-releasing air. The preheated carbide slag enters the decomposition furnace 41, and the calcium hydroxide in the carbide slag is suspended in the high-temperature heat-releasing air and decomposed by heat to produce calcium oxide, which is discharged together with the heat-releasing air. Gas-solid separation is performed through the separation cyclone 42. The separated heat-releasing air enters the preheating subunit 43 as a preheating heat source. The decomposition product enters the cooling subunit 47 to be cooled to below 100°C, and finally enters the finished product silo 48 for storage.

[0058] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art.

[0059] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tower type solar high temperature air calcining carbide slag system, characterized in that: It includes tower solar thermal receiver, heat exchanger, heat storage tank and suspended calcined carbide slag unit; The tower solar heat absorber is connected to the hot side of the heat exchanger to form a heat absorption circulation loop, in which the heat absorption medium circulates; the heat absorption medium absorbs heat in the tower solar heat absorber and releases heat in the hot side of the heat exchanger; The heat storage tank is connected to the cold side of the heat exchanger to form a heat storage circulation loop, in which the heat storage air circulates; the heat storage air absorbs heat in the cold side of the heat exchanger and releases heat in the heat storage tank; the heat storage medium in the heat storage tank absorbs the heat of the heat storage air and stores it; The heat storage tank is connected to the suspended calcined carbide slag unit to form a heat release circulation loop, in which heat release air circulates; the heat release air absorbs heat in the heat storage tank and releases heat in the suspended calcined carbide slag unit; the suspended calcined carbide slag unit uses the heat of the heat release air to decompose the carbide slag.

2. The tower type solar high temperature air calcining carbide slag system according to claim 1 is characterized in that: It also includes cooling water towers and water-cooled heat exchangers; The hot side of the water-cooled heat exchanger is arranged in the heat absorption circulation loop and connected between the hot side of the heat exchanger and the tower solar thermal absorber along the flow direction of the heat absorbing medium; if the temperature of the heat absorbing medium exceeds a threshold value, heat is released again in the hot side of the water-cooled heat exchanger; The cooling water tower and the cold side of the water-cooled heat exchanger are connected to form a cooling circulation loop, in which the cooling medium circulates; the cooling medium absorbs heat in the cold side of the water-cooled heat exchanger.

3. The tower type solar high temperature air calcining carbide slag system according to claim 2 is characterized in that: It also includes a first centrifugal water pump, a second centrifugal water pump, an air storage tank, a first variable frequency booster compressor and a second variable frequency booster compressor; The first centrifugal water pump and the second centrifugal water pump are arranged in parallel in the cooling circulation loop, and are connected between the cooling water tower and the cold side of the water-cooled heat exchanger along the flow direction of the cooling medium; The first variable frequency boost compressor and the second variable frequency boost compressor are arranged in parallel; the air storage tank and the first variable frequency boost compressor and the second variable frequency boost compressor are sequentially connected in the heat absorption circulation loop along the flow direction of the heat absorption working medium, and are arranged between the hot side of the water-cooled heat exchanger and the tower solar thermal absorber.

4. The tower type solar high temperature air calcining carbide slag system according to claim 2 is characterized in that: The heat storage tank is a double-layer heat storage tank, comprising an inner tank and an outer tank nested with each other, and both the inner tank and the outer tank are filled with solid particles; The inner tank and the outer tank of the heat storage tank are arranged in parallel in the heat storage circulation loop and the heat release circulation loop; the inner tank and the outer tank store heat and release heat respectively at the same time, and the heat storage and heat release are operated alternately in the inner tank and the outer tank.

5. The tower type solar high temperature air calcining carbide slag system according to claim 4 is characterized in that: It also includes a first cyclone separator, a first high-temperature variable-frequency fan, a second cyclone separator, and a second high-temperature variable-frequency fan; The first cyclone separator and the first high-temperature variable frequency fan are sequentially connected in the heat storage circulation loop along the flow direction of the heat storage air, and are arranged between the heat storage tank and the cold side of the heat exchanger; The second cyclone separator and the second high-temperature variable-frequency fan are both arranged in the heat release circulation loop. Along the flow direction of the heat release air, the second cyclone separator is connected between the heat storage tank and the suspended calcined carbide slag unit, and the second high-temperature variable-frequency fan is connected between the suspended calcined carbide slag unit and the heat storage tank.

6. The tower type solar high temperature air calcining carbide slag system according to claim 1 is characterized in that: The suspended calcined carbide slag unit comprises a decomposition furnace, a separation cyclone and a preheating subunit; The decomposition furnace, the separation cyclone and the preheating subunit are sequentially connected in the heat release circulation loop along the flow direction of the heat release air; The heat storage tank is connected to the decomposition furnace, and the heat-releasing air from the heat storage tank enters the decomposition furnace to decompose the carbide slag, and the decomposition products are discharged to the separation cyclone together with the heat-releasing air; the separation cyclone separates the heat-releasing air from the decomposition products; the separated heat-releasing air preheats the carbide slag before decomposition in the preheating subunit, and the preheating subunit is connected to the heat storage tank, and the preheated heat-releasing air enters the heat storage tank again.

7. The tower type solar high temperature air calcining carbide slag system according to claim 6 is characterized in that: The suspended calcined carbide slag unit also includes a carbide slag hopper, a drying crusher, a purification and impurity removal separator, a cooling subunit and a finished product silo; The carbide slag hopper, drying crusher, purification and impurity removal separator, the preheating subunit and the decomposition furnace are connected in sequence to form a feeding path; the purification and impurity removal separator is used to separate impurities in the carbide slag material; The decomposition furnace, the separation cyclone, the cooling subunit and the finished product silo are connected in sequence to form a discharge path; the cooling subunit is used to cool the decomposition products separated by the separation cyclone; The drying crusher is also arranged in the heat release circulation loop and connected between the preheating subunit and the heat storage tank along the flow direction of the heat release air; A third cyclone separator is also provided between the drying crusher and the heat storage tank.

8. The tower type solar high temperature air calcining carbide slag system according to claim 7 is characterized in that: The preheating subunit is a multi-stage preheating subunit, including a plurality of preheating cyclones; The upper part of the preheating cyclone is provided with a carbide slag inlet and a heat-releasing air inlet along the tangent direction of the cylinder, a heat-releasing air outlet is provided in the vertical direction of the top, and a carbide slag outlet is provided at the bottom; The first-stage preheating cyclone to the last-stage preheating cyclone are arranged in a left-right staggered manner from top to bottom; the carbide slag inlet of the first-stage preheating cyclone is connected to the purification and impurity removal separator; the heat-releasing air inlet of the last-stage preheating cyclone is connected to the separation cyclone; the carbide slag outlet of the last-stage preheating cyclone is connected to the decomposition furnace; the heat-releasing air outlet of the first-stage preheating cyclone is connected to the drying crusher.

9. The tower type solar high temperature air calcining carbide slag system according to claim 7, characterized in that: The cooling subunit is a multi-stage cooling subunit, including a plurality of cooling cyclones; The upper part of the cooling cyclone is provided with a decomposition product inlet and an air inlet along the tangential direction of the cylinder, an air outlet is provided in the vertical direction of the top, and a decomposition product outlet is provided at the bottom; The first-stage cooling cyclone to the last-stage cooling cyclone are arranged in a left-right staggered manner from top to bottom; the decomposition product inlet of the first-stage cooling cyclone is connected to the separation cyclone; the air is directly introduced into the air inlet of the last-stage cooling cyclone; the decomposition product outlet of the last-stage cooling cyclone is connected to the finished product silo; and the air outlet of the first-stage cooling cyclone is directly discharged to the outside.

10. A tower type solar high temperature air calcination method for carbide slag, characterized in that: The method is realized by the tower type solar high temperature air calcining carbide slag system as claimed in claim 4, comprising a heat absorption cycle, a heat storage cycle, a heat release cycle and calcining carbide slag; The working mode of the heat absorption cycle is as follows: the sunlight is reflected and concentrated to the tower solar thermal absorber through the heliostat field to make it absorb heat; the heat absorbing medium is gas; the gas enters the tower solar thermal absorber to absorb heat; the tower solar thermal absorber produces heated gas, which enters the hot side of the heat exchanger and exchanges heat with the heat storage air of the heat storage cycle to cool down, and then enters the hot side of the water-cooled heat exchanger, and finally is re-delivered to the tower solar thermal absorber to absorb heat; the heat absorption cycle is repeated; wherein, if the temperature of the gas cooled down after the heat exchange exceeds the threshold value, it exchanges heat with the cooling water of the auxiliary cooling cycle in the hot side of the water-cooled heat exchanger, and is further cooled down to below the threshold value before being re-delivered to the tower solar thermal absorber to absorb heat; if the temperature of the cooled gas does not exceed the threshold value, it is directly re-delivered to the tower solar thermal absorber to absorb heat; the working mode of the auxiliary cooling cycle is as follows: the cooling water in the cooling water tower is transported to the water-cooled heat exchanger to exchange heat with the gas in the heat absorption cycle to reduce the temperature of the gas, and the cooling water after the heat exchange re-enters the cooling water tower, and the auxiliary cooling cycle is repeated; The working mode of the heat storage cycle is as follows: the heat storage air is input into the cold side of the heat exchanger, and is heated after exchanging heat with the gas in the heat absorption cycle; the heated heat storage air enters the inner tank or outer tank of the heat storage tank, heats the solid particles, and the solid particles absorb the heat carried by the heat storage air and store it; then the heat storage air is discharged from the inner tank or outer tank of the heat storage tank and re-input into the heat exchanger, thereby repeating the heat storage cycle; The working mode of the heat release cycle is as follows: the heat release air is input into the inner tank or outer tank of the heat storage tank, and is heated by the heat stored solid particles; then the heated heat storage air is discharged from the inner tank or outer tank of the heat storage tank, enters the suspended calcined carbide slag unit to release heat and calcine the carbide slag, and finally is re-input into the inner tank or outer tank of the heat storage tank to absorb heat, thereby repeating the heat release cycle; The inner tank and the outer tank of the heat storage tank store heat and release heat respectively at the same time, and the heat storage and heat release are performed alternately in the inner tank and the outer tank.

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