Device and method for recovering phosphorus slag waste heat through air quenching and flash evaporation

Abstract

The invention relates to a device and method for recovering phosphorus slag waste heat through air quenching and flash evaporation. Comprising an air quenching chamber, a compressed air system, a gas-liquid separator, a gas storage tank, a process control sensor, a flash evaporator, a screw expander, a condenser, a generator and an energy storage device, the molten phosphorus slag flows into the air quenching chamber along the chute, and compressed air is sprayed into the air quenching chamber through the Laval spray pipe to blow away the granulated molten phosphorus slag; the crushed slag particles fall into a water tank at the bottom of the air quenching chamber to be cooled; generated water vapor forms mixed high-temperature gas, the mixed high-temperature gas is discharged from an exhaust port of a gas collecting hood at the top of the air quenching chamber, and the steam pushes a screw expander to do work; after the flash evaporator is vacuumized and depressurized, generated water vapor is discharged from the top of the flash evaporator, enters the gas-liquid separator to be separated and enters the screw expander to push the screw expander to do work and drive the power generator to generate power. The defect that waste heat cannot be recycled through a water quenching method is overcome, high-enthalpy gas generated through air quenching is recycled, waste of waste heat resources is avoided, and economic benefits are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of energy and power engineering, and in particular relates to a device and method for recovering waste heat of phosphorus slag by wind quenching flash evaporation. Background Art

[0002] Phosphorus resources are widely distributed in nature, mostly in the form of phosphate minerals, with an approximate composition of Ca3(PO4)2 or Ca5(PO4)3F. Because the combination between phosphorus and oxygen is too tight, the process of extracting elemental phosphorus from natural phosphates is complicated. Since it is very difficult to separate elemental phosphorus from compounds, the widely used method in industry is to reduce pentavalent phosphorus with carbon. The electrothermal method is to put phosphate ore, coke and silica raw materials into an electric furnace in proportion to react, then spray cool the furnace gas to obtain crude phosphorus, and then introduce the crude phosphorus into a refining tank for two-stage refining to finally obtain a yellow phosphorus product. At the same time, a large amount of phosphorus slag waste will be generated in the process of producing yellow phosphorus, which will cause environmental pollution if not recycled.

[0003] Yellow phosphorus slag is a solid waste of phosphorus slag produced when yellow phosphorus is prepared by electric furnace method. For every ton of yellow phosphorus produced, about 8 to 10 tons of yellow phosphorus slag are produced. The total annual output of yellow phosphorus slag in China exceeds 7 million tons. The temperature of yellow phosphorus furnace slag is as high as 1400 to 1500℃. The heat taken away by yellow phosphorus slag accounts for about 30% of the total energy consumption. It has obvious waste heat utilization value. At present, the treatment of yellow phosphorus slag is mainly water quenching. This treatment method not only wastes the waste heat of molten yellow phosphorus slag, but also causes waste and pollution of water resources; at the same time, the solid phosphorus slag particles produced are easy to stick together into blocks, which is not conducive to recycling.

[0004] Slag refers to the melt mainly composed of oxides generated during the metallurgical process. There are many methods for treating slag in the industry. For example, the water quenching method is to use the dual effects of large flow, high-pressure water and slag flow to rapidly granulate and cool the slag under the dual effects of internal stress generated by rapid cooling and contraction. The centrifugal granulation method is to pour the liquid slag flow into the center of a high-speed rotating cup or disc. Under the action of centrifugal force, the slag flow spreads to the edge in the form of a liquid film on the surface of the granulator and radiates in the form of droplets. Then the waste heat is recovered at the water-cooled wall, fluidized bed, and moving bed. The hot stuffy method is to use the sensible heat of high-temperature liquid slag to sprinkle water, produce physical and mechanical effects and the digestion of free calcium oxide, so as to fragment the slag. The drum method refers to the high-temperature liquid slag in a high-speed rotating drum, using water as a cooling medium, to rapidly cool, solidify, and crush. The wind quenching method refers to the liquid slag being crushed by shearing and other actions under the strong impact and cooling effect of high-pressure airflow.

[0005] The wind quenching method is often used in the industry to treat molten steel slag. After the slag pot receives the slag, it is transported to the wind quenching device, the slag pot is tilted, the molten slag flows out through the intermediate tank, is blown away by the air sprayed from the nozzle, and is broken into slag particles. The heat dissipated in the high-temperature air and slag particles is recovered in the hood boiler and the slag particles are captured. Therefore, the wind quenching method for treating blast furnace slag can not only recover the waste heat generated, but also obtain finer solid slag particles; at the same time, the slag particles have a wider range of uses after recovery and have better utilization value. Based on the advantages of the above-mentioned wind quenching method, in order to make full use of the waste heat resources of high-temperature yellow phosphorus slag and take into account the resource utilization of yellow phosphorus slag after waste heat recovery, a method of treating yellow phosphorus slag by wind quenching is proposed.

[0006] At present, the waste heat recovery technologies mainly include low-quality waste heat recovery technology and chemical waste heat recovery technology. Among them, the low-quality waste heat recovery technology uses a steam-water heat exchanger to use hot steam as a heat source to obtain hot water with relatively stable temperature and flow, and then introduces the hot water into the organic Rankine cycle system. The heat is first transferred to the low-boiling point organic circulating working fluid in the system, and then the liquid working fluid changes phase into steam at a certain pressure, and finally expands and works in the expander to drive the generator to generate electricity; the chemical waste heat recovery technology uses endothermic chemical reactions to fix the heat contained in the high-temperature slag to the high-energy chemical bonds of the reaction products. This method The waste heat recovery technology has low thermal efficiency. Although the efficiency of thermochemical waste heat recovery technology is high, there are still many engineering and technical problems that have not been solved, and it is difficult to put it into practical engineering applications.

[0007] Usually, yellow phosphorus furnaces in industry discharge slag once every 4 hours. The discontinuity of slag discharge and the intermittent air quenching produce gas, which is not conducive to the continuous operation of heat recovery and the continuous use of heat after recovery. The flash evaporation method uses hot water to enter the flash evaporator, and the pressure is reduced by vacuuming, so that the boiling point of water is reduced to produce saturated steam, which enters the steam turbine to generate work and generate electricity. At the same time, after the water at the bottom of the air quenching chamber in the present invention comes into contact with the fallen slag particles, the temperature of the water is increased and becomes hot water. This part of hot water can also be introduced into the flash evaporator for flash evaporation. Therefore, the present invention introduces flash evaporation technology to make up for the intermittent period of slag discharge, and proposes a comprehensive utilization method for recovering the waste heat of phosphorus slag by air quenching and flash evaporation. Summary of the invention

[0008] The object of the present invention is to provide a device and method for recovering waste heat of phosphorus slag by wind quenching flash evaporation, so as to solve the technical problems raised in the background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The invention provides a device for recovering phosphorus slag waste heat by wind quenching flash evaporation, comprising a wind quenching chamber, a compressed air system, a gas-liquid separator, a gas storage tank, a process control sensor, a flash evaporator, a screw expander, a condenser, a generator and an energy storage device.

[0011] Furthermore, the air quenching chamber includes a slag inlet, a nozzle, a lining, a water pool, an exhaust port, an air sensor, a temperature sensor, a water replenishment device and a pressure sensor. The slag inlet is used for molten phosphorus slag to flow into the air quenching chamber at a flow rate of 20 to 80 t / h; the nozzle is a Laval nozzle installed in a double-row tube bundle; the lining is a Q345B steel structure that is resistant to high temperature and high pressure.

[0012] Furthermore, the water pool is used to cool the slag particles that fall after crushing, and the water pool is provided with a water replenishing device. When the water level line is lower than a predetermined water level, the water replenishing device automatically starts to replenish water; the exhaust port is used to discharge a mixed gas with a temperature of 200 to 500°C and a pressure of 0.15 to 3Mpa; the air sensor and temperature sensor are used to sense the air flow and temperature in the wind quenching chamber; the pressure sensor is used to monitor the pressure in the wind quenching chamber. When the pressure exceeds the safety pressure, the safety device automatically opens the exhaust port connected to the outside world to exhaust air, thereby ensuring the safety of the wind quenching chamber.

[0013] Furthermore, the compressed air system includes an air compressor, an air storage tank, a filter, a dryer, and a gas pipeline. The volume flow rate of the compressed air system is 10 to 200 m 3 / min, the working pressure is 0.3~3Mpa; the air compressor is used to compress the air at atmospheric pressure and output it at a higher pressure; the air storage tank is used to store compressed air; the filter is used to remove dust, moisture and oil; the dryer is used to dry the compressed air; the gas pipeline is used to transport the compressed air to the use point.

[0014] Furthermore, the gas tank is coated with an insulation layer for storing the gas separated by the gas-liquid separator; a heating coil is provided in the gas tank, and the hot steam in the coil is used to insulate the gas tank; an external electric heater can also be used, and the electric energy required for heating comes from the energy storage device; or steam and electric heating can be used simultaneously; the gas-liquid separator is used to separate the gas and store it in the gas tank.

[0015] Furthermore, the flash evaporator is a pressure vessel coated with anti-corrosion material inside and thermal insulation material outside. The flash evaporator evacuates and reduces the pressure of the hot water in the container to reduce the vacuum degree to the flash evaporation range of the hot water. At this time, the hot water reaches the boiling point and becomes saturated steam, which is used as a circulating medium to generate electricity.

[0016] Furthermore, the pressure sensor is an artificial intelligence pressure sensor used to monitor the pressure in the wind quenching chamber and the gas storage tank.

[0017] Furthermore, the screw expander is a positive displacement fluid machine. When gas enters the screw expander, it expands and drives the screw to rotate, converting thermal energy into mechanical energy, thereby driving the generator to generate electrical energy.

[0018] Furthermore, the condenser condenses the gas after work into liquid, which flows back into the wind quenching chamber to cool the fallen slag particles; the generator is used to convert the mechanical energy generated by the screw expander into electrical energy, and a stepless transmission is connected between the generator and the screw expander to adapt to different working conditions; the energy storage device is used to store the generated electrical energy and generate electricity using photovoltaic heating panels, and the stored electrical energy is used to insulate and heat the steam storage tank.

[0019] The present invention also provides a method for recovering waste heat of phosphorus slag by wind quenching and flash evaporation. The molten phosphorus slag flows into the wind quenching chamber along the chute, and the compressed air is sprayed into the wind quenching chamber through the Laval nozzle to blow away and granulate the molten phosphorus slag; the crushed slag particles fall into the water pool at the bottom of the wind quenching chamber for cooling; at the same time, the water in the water pool absorbs heat and the temperature rises to become hot water; after the hot air and water after wind quenching are cooled, the generated water vapor forms a mixed high-temperature gas, which is discharged from the exhaust port of the gas collecting hood at the top of the wind quenching chamber. After the mixed gas is separated by the gas-liquid separator, the hot mixed water vapor is stored in the gas storage tank; when the wind quenching in the wind quenching chamber is completed, the pressure sensor connected to the gas storage tank detects that the outlet pressure of the exhaust port reaches the set value, and then automatically opens to allow steam to enter. Enter the screw expander, push the screw expander to do work; when the pressure sensor connected to the water pool at the bottom of the wind quenching chamber monitors that the pressure in the gas storage tank has dropped to a certain value, it means that the gas in the gas storage tank has finished doing work; at this time, close the exhaust port of the gas storage tank; open the bottom water pool switch, and hot water flows into the flash evaporator; after vacuuming and reducing the pressure in the flash evaporator, the generated water vapor is discharged from the top of the flash evaporator into the gas-liquid separator for separation, and then enters the screw expander, pushing the screw expander to do work, driving the generator to generate electricity, ensuring the continuity of power generation, and the generated electrical energy is stored in the energy storage device connected to the generator, or sent out; finally, the gas after doing work in the screw expander is condensed into liquid by the condenser, and then circulated back to the wind quenching chamber for reuse.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention adopts the air quenching method to treat molten phosphorus slag to solve the defect that the water quenching method cannot recover waste heat, recycles and utilizes the high enthalpy gas generated by the air quenching, avoids the waste of waste heat resources, and improves economic benefits. Most of the solid slag particles obtained by treating molten phosphorus slag by the air quenching method have a particle size of less than 3 mm, which has a wider range of uses and a higher comprehensive utilization value. A water pool is set in the air quenching chamber to effectively absorb large particle impurities in the air quenching process, thereby improving the quality of the exhaust flue gas to a certain extent. The present invention introduces a flash evaporator, combined with flash evaporation technology, to solve the problem of intermittent gas generation, resulting in unsustainable power generation. The present invention selects a screw expander suitable for waste heat flue gas to do work, and converts thermal energy into mechanical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0023] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0024] Figure 1 The invention discloses a waste heat recovery process flow chart of a device and method for recovering waste heat of phosphorus slag by wind quenching flash evaporation;

[0025] Figure 2 The schematic diagram of the nozzle structure of the patent of the present invention is shown;

[0026] Figure 3 A schematic diagram of the structure of the wind quenching chamber is shown;

[0027] Figure 4 A schematic diagram of the flash evaporator structure is shown;

[0028] The above drawings include the following reference numerals:

[0029] 1-wind quenching chamber; 2-compressed air system; 3-pressure sensor 1; 4-flash evaporator; 5-first gas-liquid separator; 6-condenser; 7-screw expander; 8-stepless transmission; 9-generator; 10-energy storage device; 11-pressure sensor 2; 12-gas storage tank; 13-second gas-liquid separator; 14-temperature sensor; 15-slag inlet; 16-nozzle; 17-water replenishment device; 18-water tank; 19-lining; 20-pressure sensor; 21-exhaust port; 22-air sensor. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] The present invention provides a device and method for recovering waste heat of phosphorus slag by wind quenching and flash evaporation; the required devices include a wind quenching chamber 1, a compressed air system 2, a gas-liquid separator 5, 13, a gas storage tank 12, a process control sensor, a flash evaporator 4, a screw expander 7, a condenser, a generator 9 and an energy storage device 10. The method flow is as follows: molten phosphorus slag flows into the wind quenching chamber along a chute, and compressed air is sprayed into the wind quenching chamber through a Laval nozzle to blow away and granulate the molten phosphorus slag. The crushed slag particles fall into a pool at the bottom of the wind quenching chamber for cooling. At the same time, the water in the pool absorbs heat and the temperature rises, becoming hot water. After the hot air and water after wind quenching are cooled, the generated water vapor forms a mixed high-temperature gas, which is discharged from the exhaust port of the gas collecting hood at the top of the wind quenching chamber. After the mixed gas is separated by the gas-liquid separator, the hot mixed water vapor is stored in the gas storage tank. When the wind quenching in the wind quenching chamber is completed, the pressure sensor connected to the gas storage tank automatically opens after monitoring that the outlet pressure of the exhaust port reaches the set value, and the steam enters the screw expander to drive the screw expander to do work. When the pressure sensor connected to the water pool at the bottom of the wind quenching chamber detects that the pressure in the gas tank has dropped to a certain value, it means that the gas in the gas tank has finished working. At this time, close the exhaust port of the gas tank. Open the bottom water pool switch and hot water flows into the flash evaporator. After vacuuming and reducing the pressure in the flash evaporator, the generated water vapor is discharged from the top of the flash evaporator into the gas-liquid separator for separation, and then enters the screw expander, pushing the screw expander to work, driving the generator to generate electricity, ensuring the continuity of power generation, and the generated electricity is stored in the energy storage device connected to the generator, or sent out. Finally, the gas after the screw expander has done work is condensed into liquid by the condenser and circulated back to the wind quenching chamber for reuse.

[0033] The air quenching chamber includes a slag inlet 15, a nozzle 16, a lining 19, a water pool 18, an exhaust port 21, an air sensor 22, a temperature sensor 14, a water supply device 17 and a pressure sensor 20. The slag inlet is used for molten phosphorus slag to flow into the air quenching chamber at a flow rate of 20t / h; the nozzle is a Laval nozzle, which is installed in a double-row tube bundle (three nozzles in one bundle), and the material is a high-temperature resistant copper-nickel material (density: 8.9g / cm3, yield strength: ≥195Mpa, and can withstand a high temperature of 550℃). The inner wall of the nozzle is micro-processed, and the Mach number is controlled at 1.5. The lining is a high-temperature and high-pressure resistant Q345B steel structure (density: 7.85g / cm3, yield strength: ≥345Mpa, and can withstand a high pressure of 31.4Mpa).

[0034] The water pool is used to cool the slag particles that fall after crushing, and the water pool is provided with a water replenishing device. When the water level line is lower than the set water level, the water replenishing device automatically starts to replenish water; the exhaust port is used to discharge the mixed gas with a temperature of 250°C and a pressure of 0.3Mpa; the intelligent air sensor and the intelligent temperature sensor are used to sense the air flow and temperature in the wind quenching chamber; the pressure sensor is used to monitor the pressure in the wind quenching chamber. When the pressure exceeds the safety pressure, the safety device automatically opens the exhaust port connected to the outside world to exhaust air, thereby ensuring the safety of the wind quenching chamber.

[0035] The compressed air system includes an air compressor, an air storage tank, a filter, a dryer, and an air pipeline. The volume flow of the compressed air system is 33.8m 3 / min, and the working pressure is 1.1Mpa; the air compressor is used to compress the air at atmospheric pressure and output it at a higher pressure; the air storage tank is used to store compressed air; the filter is used to remove dust, moisture and oil. The dryer is used to dry the compressed air; the air pipeline is used to transport the compressed air to the point of use.

[0036] The gas storage tank is coated with a heat-insulating layer for storing the gas separated by the gas-liquid separator. A heating coil is provided in the gas storage tank, and the hot steam in the coil is used to keep the gas storage tank warm. An external electric heater can also be used, and the electric energy required for heating comes from the energy storage device. Alternatively, steam and electric heating can be used simultaneously.

[0037] The gas-liquid separator is used to separate the gas and store it in a gas storage tank.

[0038] The flash evaporator is a pressure vessel with an anti-corrosion material inside and a heat-insulating material outside. The flash evaporator evacuates and reduces the pressure of the hot water in the container to reduce the vacuum degree to the flash evaporation range of the hot water. At this time, the hot water reaches the boiling point and becomes saturated steam, which is used as a circulating medium to generate electricity.

[0039] The pressure sensor is an artificial intelligence pressure sensor used to monitor the pressure in the wind quenching chamber and the gas storage tank.

[0040] The screw expander is a volumetric fluid machine. When gas enters the screw expander, it expands and pushes the screw to rotate, converting heat energy into mechanical energy, which drives the generator to generate electrical energy.

[0041] The condenser condenses the gas after work into liquid, which flows back into the wind quenching chamber to cool the fallen slag particles.

[0042] The generator is used to convert the mechanical energy generated by the screw expander into electrical energy. A stepless transmission is connected between the generator and the screw expander to adapt to different working conditions.

[0043] The energy storage device is used to store the generated electric energy and generate electricity using the photovoltaic electric heating panel, and the stored electric energy is used to heat the steam storage tank.

[0044] Example 2

[0045] A device and method for recovering waste heat of phosphorus slag by air quenching and flash evaporation. The required devices include an air quenching chamber, a compressed air system, a gas-liquid separator, a gas storage tank, a process control sensor, a flash evaporator, a screw expander, a condenser, a generator and an energy storage device. The method flow is as follows: the molten phosphorus slag flows into the air quenching chamber along the chute, and the compressed air is sprayed into the air quenching chamber through the Laval nozzle to blow away and granulate the molten phosphorus slag. The crushed slag particles fall into the pool at the bottom of the air quenching chamber for cooling. At the same time, the water in the pool will absorb heat and increase its temperature to become hot water. After the hot air and water after air quenching are cooled, the generated water vapor forms a mixed high-temperature gas, which is discharged from the exhaust port of the gas collecting hood at the top of the air quenching chamber. After the mixed gas is separated by the gas-liquid separator, the hot mixed water vapor is stored in the gas storage tank. When the air quenching in the air quenching chamber is completed, the pressure sensor connected to the gas storage tank automatically opens after monitoring that the outlet pressure of the exhaust port reaches the set value, and the steam enters the screw expander to drive the screw expander to do work. When the pressure sensor connected to the water pool at the bottom of the wind quenching chamber detects that the pressure in the gas tank has dropped to a certain value, it means that the gas in the gas tank has finished working. At this time, close the exhaust port of the gas tank. Open the bottom water pool switch and hot water flows into the flash evaporator. After vacuuming and reducing the pressure in the flash evaporator, the generated water vapor is discharged from the top of the flash evaporator into the gas-liquid separator for separation, and then enters the screw expander, pushing the screw expander to work, driving the generator to generate electricity, ensuring the continuity of power generation, and the generated electricity is stored in the energy storage device connected to the generator, or sent out. Finally, the gas after the screw expander has done work is condensed into liquid by the condenser and circulated back to the wind quenching chamber for reuse.

[0046] The air quenching chamber includes a slag inlet, a nozzle, a lining, a water pool, an exhaust port, an air sensor, a temperature sensor, a water supply device and a pressure sensor. The slag inlet is used for molten phosphorus slag to flow into the air quenching chamber at a flow rate of 60t / h; the nozzle uses a Laval nozzle, which is installed in a double-row tube bundle (a bundle of 7 nozzles), and the material is a high-temperature resistant copper-nickel material (density: 8.9g / cm3, yield strength: ≥195Mpa, and can withstand a high temperature of 550℃). The inner wall of the nozzle is micro-processed, and the Mach number is controlled at 1.5. The lining uses a high-temperature and high-pressure resistant Q345B steel structure (density: 7.85g / cm3, yield strength: ≥345Mpa, and can withstand a high pressure of 31.4Mpa).

[0047] The water pool is used to cool the slag particles that fall after crushing, and the water pool is provided with a water replenishing device. When the water level line is lower than the set water level, the water replenishing device automatically starts to replenish water; the exhaust port is used to discharge the mixed gas with a temperature of 350°C and a pressure of 0.5Mpa; the intelligent air sensor and the intelligent temperature sensor are used to sense the air flow and temperature in the wind quenching chamber; the pressure sensor is used to monitor the pressure in the wind quenching chamber. When the pressure exceeds the safety pressure, the safety device automatically opens the exhaust port connected to the outside world to exhaust air, thereby ensuring the safety of the wind quenching chamber.

[0048] The compressed air system includes an air compressor, an air storage tank, a filter, a dryer, and an air pipeline. The volume flow rate of the compressed air system is 40.5m 3 / min, the working pressure is 1Mpa; the air compressor is used to compress the air at atmospheric pressure and output it at a higher pressure; the air storage tank is used to store compressed air; the filter is used to remove dust, moisture and oil. The dryer is used to dry the compressed air; the air pipeline is used to transport the compressed air to the point of use.

[0049] The gas storage tank is coated with a heat-insulating layer for storing the gas separated by the gas-liquid separator. A heating coil is provided in the gas storage tank, and the hot steam in the coil is used to keep the gas storage tank warm. An external electric heater can also be used, and the electric energy required for heating comes from the energy storage device. Alternatively, steam and electric heating can be used simultaneously.

[0050] The gas-liquid separator is used to separate the gas and store it in a gas storage tank.

[0051] The flash evaporator is a pressure vessel with an anti-corrosion material inside and a heat-insulating material outside. The flash evaporator evacuates and reduces the pressure of the hot water in the container to reduce the vacuum degree to the flash evaporation range of the hot water. At this time, the hot water reaches the boiling point and becomes saturated steam, which is used as a circulating medium to generate electricity.

[0052] The pressure sensor is an artificial intelligence pressure sensor used to monitor the pressure in the wind quenching chamber and the gas storage tank.

[0053] The screw expander is a volumetric fluid machine. When gas enters the screw expander, it expands and pushes the screw to rotate, converting heat energy into mechanical energy, which drives the generator to generate electrical energy.

[0054] The condenser condenses the gas after work into liquid, which flows back into the wind quenching chamber to cool the fallen slag particles.

[0055] The generator is used to convert the mechanical energy generated by the screw expander into electrical energy. A stepless transmission is connected between the generator and the screw expander to adapt to different working conditions.

[0056] The energy storage device is used to store the generated electric energy and generate electricity using the photovoltaic electric heating panel, and the stored electric energy is used to heat the steam storage tank.

[0057] Example 3

[0058] A device and method for recovering waste heat of phosphorus slag by air quenching and flash evaporation. The required devices include an air quenching chamber, a compressed air system, a gas-liquid separator, a gas storage tank, a process control sensor, a flash evaporator, a screw expander, a condenser, a generator and an energy storage device. The method flow is as follows: the molten phosphorus slag flows into the air quenching chamber along the chute, and the compressed air is sprayed into the air quenching chamber through the Laval nozzle to blow away and granulate the molten phosphorus slag. The crushed slag particles fall into the pool at the bottom of the air quenching chamber for cooling. At the same time, the water in the pool will absorb heat and increase its temperature to become hot water. After the hot air and water after air quenching are cooled, the generated water vapor forms a mixed high-temperature gas, which is discharged from the exhaust port of the gas collecting hood at the top of the air quenching chamber. After the mixed gas is separated by the gas-liquid separator, the hot mixed water vapor is stored in the gas storage tank. When the air quenching in the air quenching chamber is completed, the pressure sensor connected to the gas storage tank automatically opens after monitoring that the outlet pressure of the exhaust port reaches the set value, and the steam enters the screw expander to drive the screw expander to do work. When the pressure sensor connected to the water pool at the bottom of the wind quenching chamber detects that the pressure in the gas tank has dropped to a certain value, it means that the gas in the gas tank has finished working. At this time, close the exhaust port of the gas tank. Open the bottom water pool switch and hot water flows into the flash evaporator. After vacuuming and reducing the pressure in the flash evaporator, the generated water vapor is discharged from the top of the flash evaporator into the gas-liquid separator for separation, and then enters the screw expander, pushing the screw expander to work, driving the generator to generate electricity, ensuring the continuity of power generation, and the generated electricity is stored in the energy storage device connected to the generator, or sent out. Finally, the gas after the screw expander has done work is condensed into liquid by the condenser and circulated back to the wind quenching chamber for reuse.

[0059] The air quenching chamber includes a slag inlet, a nozzle, a lining, a water pool, an exhaust port, an air sensor, a temperature sensor, a water supply device and a pressure sensor. The slag inlet is used for molten phosphorus slag to flow into the air quenching chamber at a flow rate of 80t / h; the nozzle is a Laval nozzle, which is installed in a double-row tube bundle (10 nozzles in a bundle), and the material is a high-temperature resistant copper-nickel material (density: 8.9g / cm3, yield strength: ≥195Mpa, and can withstand a high temperature of 550℃). The inner wall of the nozzle is micro-processed, and the Mach number is controlled at 1.5. The lining adopts a high-temperature and high-pressure resistant Q345B steel structure (density: 7.85g / cm3, yield strength: ≥345Mpa, and can withstand a high pressure of 31.4Mpa).

[0060] The water pool is used to cool the slag particles that fall after crushing, and the water pool is provided with a water replenishing device. When the water level is lower than the set water level, the water replenishing device automatically starts to replenish water; the exhaust port is used to discharge the mixed gas with a temperature of 450°C and a pressure of 0.8Mpa; the intelligent air sensor and the intelligent temperature sensor are used to sense the air flow and temperature in the wind quenching chamber; the pressure sensor is used to monitor the pressure in the wind quenching chamber. When the pressure exceeds the safety pressure, the safety device automatically opens the exhaust port connected to the outside world to exhaust air, thereby ensuring the safety of the wind quenching chamber.

[0061] The compressed air system includes an air compressor, an air storage tank, a filter, a dryer, and an air pipeline. The volume flow rate of the compressed air system is 50m 3 / min, the working pressure is 0.8Mpa; the air compressor is used to compress the air at atmospheric pressure and output it at a higher pressure; the air storage tank is used to store compressed air; the filter is used to remove dust, moisture and oil. The dryer is used to dry the compressed air; the air pipeline is used to transport the compressed air to the point of use.

[0062] The gas storage tank is coated with a heat-insulating layer for storing the gas separated by the gas-liquid separator. A heating coil is provided in the gas storage tank, and the hot steam in the coil is used to keep the gas storage tank warm. An external electric heater can also be used, and the electric energy required for heating comes from the energy storage device. Alternatively, steam and electric heating can be used simultaneously.

[0063] The gas-liquid separator is used to separate the gas and store it in a gas storage tank.

[0064] The flash evaporator is a pressure vessel with an anti-corrosion material inside and a heat-insulating material outside. The flash evaporator evacuates and reduces the pressure of the hot water in the container to reduce the vacuum degree to the flash evaporation range of the hot water. At this time, the hot water reaches the boiling point and becomes saturated steam, which is used as a circulating medium to generate electricity.

[0065] The pressure sensor is an artificial intelligence pressure sensor used to monitor the pressure in the wind quenching chamber and the gas storage tank.

[0066] The screw expander is a volumetric fluid machine. When gas enters the screw expander, it expands and pushes the screw to rotate, converting heat energy into mechanical energy, which drives the generator to generate electrical energy.

[0067] The condenser condenses the gas after work into liquid, which flows back into the wind quenching chamber to cool the fallen slag particles.

[0068] The generator is used to convert the mechanical energy generated by the screw expander into electrical energy. A stepless transmission is connected between the generator and the screw expander to adapt to different working conditions.

[0069] The energy storage device is used to store the generated electric energy and generate electricity using the photovoltaic electric heating panel, and the stored electric energy is used to heat the steam storage tank.

[0070] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for recovering waste heat of phosphorus slag by wind quenching flash evaporation, characterized in that: It includes air quenching chamber, compressed air system, gas-liquid separator, gas storage tank, process control sensor, flash evaporator, screw expander, condenser, generator and energy storage device.

2. The device for recovering phosphorus slag waste heat by wind quenching flash evaporation according to claim 1 is characterized in that: The air quenching chamber includes a slag inlet, a nozzle, a lining, a water pool, an exhaust port, an air sensor, a temperature sensor, a water replenishment device and a pressure sensor. The slag inlet is used for molten phosphorus slag to flow into the air quenching chamber at a flow rate of 20 to 80 t / h; the nozzle is a Laval nozzle, which is installed in a double-row tube bundle; the lining adopts a high temperature and high pressure resistant Q345B steel structure.

3. The device for recovering phosphorus slag waste heat by wind quenching flash evaporation according to claim 2 is characterized in that: The water pool is used to cool the slag particles that fall after crushing, and the water pool is provided with a water replenishing device. When the water level is lower than the set water level, the water replenishing device automatically starts to replenish water; the exhaust port is used to discharge a mixed gas with a temperature of 200-500°C and a pressure of 0.15-3Mpa; the air sensor and temperature sensor are used to sense the air flow and temperature in the wind quenching chamber; the pressure sensor is used to monitor the pressure in the wind quenching chamber. When the pressure exceeds the safety pressure, the safety device automatically opens the exhaust port connected to the outside world to exhaust air, thereby ensuring the safety of the wind quenching chamber.

4. The device for recovering phosphorus slag waste heat by wind quenching flash evaporation according to claim 1 is characterized in that: The compressed air system includes an air compressor, an air storage tank, a filter, a dryer, and an air pipeline. The volume flow rate of the compressed air system is 10 to 200 m 3 / min, and the working pressure is 0.3-3Mpa; the air compressor is used to compress the air at atmospheric pressure and output it at a higher pressure; the air storage tank is used to store compressed air; The filter is used to remove dust, moisture and oil; the dryer is used to dry compressed air; and the air pipeline is used to transport compressed air to the point of use.

5. The device for recovering waste heat of phosphorus slag by wind quenching flash evaporation according to claim 1 is characterized in that: The gas storage tank is coated with an insulation layer for storing the gas separated by the gas-liquid separator; a heating coil is arranged in the gas storage tank, and the hot steam in the coil is used to keep the gas storage tank warm; an external electric heater can also be used, and the electric energy required for heating comes from the energy storage device; or steam and electric heating can be used simultaneously; the gas-liquid separator is used to separate the gas and store it in the gas storage tank.

6. The device for recovering waste heat of phosphorus slag by wind quenching flash evaporation according to claim 1 is characterized in that: The flash evaporator is a pressure vessel coated with anti-corrosion material inside and heat-insulating material outside. The flash evaporator evacuates and reduces the pressure of the hot water in the container to reduce the vacuum degree to the flash evaporation range of the hot water. At this time, the hot water reaches the boiling point and becomes saturated steam, which is used as a circulating medium to generate electricity.

7. The device for recovering phosphorus slag waste heat by wind quenching flash evaporation according to claim 3 is characterized in that: The pressure sensor is an artificial intelligence pressure sensor, which is used to monitor the pressure in the wind quenching chamber and the gas storage tank.

8. The device for recovering waste heat of phosphorus slag by wind quenching flash evaporation according to claim 7 is characterized in that: The screw expander is a volumetric fluid machine. When gas enters the screw expander, it expands and drives the screw to rotate, converting thermal energy into mechanical energy, driving the generator to generate electrical energy.

9. The device for recovering waste heat of phosphorus slag by wind quenching flash evaporation according to claim 8, characterized in that: The condenser condenses the gas after work into liquid, which flows back into the wind quenching chamber to cool the fallen slag particles; the generator is used to convert the mechanical energy generated by the screw expander into electrical energy, and a stepless transmission is connected between the generator and the screw expander to adapt to different working conditions; the energy storage device is used to store the generated electrical energy and generate electricity using photovoltaic heating panels, and the stored electrical energy is used to insulate and heat the steam storage tank.

10. A method for recovering waste heat of phosphorus slag by air quenching flash evaporation, characterized in that: The molten phosphorus slag flows into the quenching chamber along the chute, and the compressed air is sprayed into the quenching chamber through the Laval nozzle to blow away and granulate the molten phosphorus slag; the crushed slag particles fall into the water pool at the bottom of the quenching chamber for cooling; at the same time, the water in the water pool absorbs heat and the temperature rises, turning into hot water; after the hot air and water after quenching are cooled, the generated water vapor forms a mixed high-temperature gas, which is discharged from the exhaust port of the gas collecting hood at the top of the quenching chamber. After the mixed gas is separated by the gas-liquid separator, the hot mixed water vapor is stored in the gas storage tank; when the quenching in the quenching chamber is completed, the pressure sensor connected to the gas storage tank detects that the outlet pressure of the exhaust port reaches the set value, and it automatically opens, and the steam enters the screw expander to drive the screw expander to do work; when the pressure sensor connected to the water pool at the bottom of the quenching chamber detects that the pressure in the gas storage tank has dropped to a certain value, it means that the gas in the gas storage tank has finished doing work; at this time, the exhaust port of the gas storage tank is closed; Turn on the bottom water tank switch and hot water flows into the flash evaporator; after vacuuming and reducing the pressure in the flash evaporator, the generated water vapor is discharged from the top of the flash evaporator and enters the gas-liquid separator for separation, and then enters the screw expander, pushing the screw expander to do work, driving the generator to generate electricity, ensuring the continuity of power generation, and the generated electric energy is stored in the energy storage device connected to the generator, or sent out; finally, the gas after the screw expander has done work is condensed into liquid by the condenser, and then circulated back to the wind quenching chamber for reuse.

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