A low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas

Abstract

The present invention provides a low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas, which belongs to the technical field of acid production and waste heat recovery, and solves the technical problems of poor effect and high cost of existing acid production and waste heat recovery. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas comprises a high-temperature absorption tower, an evaporator, a deoxygenated water heater, a deaerator and a desalted water heater, wherein a first packing layer and a second packing layer are arranged inside the high-temperature absorption tower, a first spray absorption system is arranged above the first packing layer, a second spray absorption system is arranged above the second packing layer, an air inlet is arranged on the high-temperature absorption tower, a high-temperature circulation tank is connected to the lower end of the high-temperature absorption tower through a recovery pipeline, a high-temperature circulation tank is connected to a high-temperature circulation acid pump through a pipeline, and the high-temperature circulation acid pump is connected to the sulfuric acid inlet of the evaporator through a pipeline. The present invention has the advantages of improving the effect of acid production and waste heat recovery and reducing the cost of use.

Description

Technical Field

[0001] The invention belongs to the technical field of acid production and waste heat recovery, and relates to a low-temperature waste heat recovery system, in particular to a low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas. Background Art

[0002] Chinese patent literature discloses a converter copper smelting system based on a sulfuric acid low-temperature waste heat recovery system [Application No.: 202120038208.8; Announcement No.: CN 214529191U]. This converter copper smelting system includes a sulfuric acid low-temperature waste heat recovery system, the sulfuric acid low-temperature waste heat recovery system includes a high-temperature absorption tower with an input pipe, the converter copper smelting system also includes a flow meter, and the flow meter is arranged on the input pipe of the high-temperature absorption tower; the converter copper smelting system also includes a cold and heat exchange system, a secondary sulfuric acid circulation system and a desalted water treatment system, and the cold and heat exchange system, the secondary sulfuric acid circulation system and the desalted water treatment system are respectively connected to the sulfuric acid low-temperature waste heat recovery system. By using the sulfuric acid low-temperature waste heat recovery system for converter copper smelting, the technical gap in the industry is filled, and the technical application upgrade for converter copper smelting is brought; a flow meter is installed to cope with the large fluctuations in the smelting flue gas volume and the sulfur dioxide concentration in the flue gas during the converter blowing process.

[0003] In view of the above technologies, in recent years, various manufacturers in the market have continued to improve and upgrade the HRS system, and have better realized the recovery and utilization efficiency of flue gas heat and sulfur dioxide gas. However, the HRS system currently in use has a large deoxygenation tower, which cannot be used on the ground floor, occupies a large area, and is difficult to install and maintain. At the same time, when the flue gas enters the high-temperature absorption tower, the flue gas is continuously sent in. Due to the large volume of the high-temperature absorption tower and the small size of the flue gas pipeline relative to the diameter of the high-temperature absorption tower, the flue gas cannot be well dispersed in the high-temperature absorption tower after entering the high-temperature absorption tower, which reduces the effect of acid production and waste heat recovery. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas. The technical problem to be solved by the invention is: how to improve the effect of acid production and waste heat recovery and reduce the cost of use.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas comprises a high-temperature absorption tower, an evaporator, a deoxygenated water heater, a deaerator and a desalted water heater, wherein a first packing layer and a second packing layer are arranged inside the high-temperature absorption tower, a first spray absorption system is arranged above the first packing layer, a second spray absorption system is arranged above the second packing layer, an air inlet is arranged on the high-temperature absorption tower, a high-temperature circulation tank is connected to the lower end of the high-temperature absorption tower through a recovery pipeline, a high-temperature circulation tank is connected to a high-temperature circulation acid pump through a pipeline, and the high-temperature circulation acid pump is connected to the sulfuric acid inlet of the evaporator through a pipeline, The first sulfuric acid outlet of the evaporator is connected to the deoxygenated water heater, the deaerator and the desalted water heater in sequence, the second sulfuric acid outlet of the evaporator is connected to the sulfuric acid inlet of the mixer, the mixer is connected to the second spray absorption system through a pipeline, the outlet of the deoxygenated water heater is connected to the inlet of the deaerator heating pipe through a pipeline, the outlet of the deoxygenated water heating pipe is connected to the hot water pump, and the outlet of the hot water pump is connected to the water supply inlet of the hot water storage tank in the deaerator; in addition, the water supply outlet of the deoxygenated water heater is connected to the deoxygenated water inlet of the deaerator, and the deoxygenated water outlet of the deaerator is connected to the water inlet of the evaporator and the water inlet of the diluter through the water supply pump;

[0007] The high-temperature absorption tower is provided with a plurality of air inlets distributed in a ring shape, an annular tube is fixed on the outer side of the high-temperature absorption tower, a plurality of air outlet pipes are fixed on the inner circumference of the annular tube, the air outlet pipes extend into the interior of the high-temperature absorption tower through the air inlets, an air inlet pipe is fixed on the annular tube, the other end of the air inlet pipe is connected with the air outlet end of the steam ejector, the air inlet end of the steam ejector is connected with the steam inlet, a valve is fixed on the air inlet end of the steam ejector, a cache box is fixed on the other end of the valve, a flue gas inlet pipe is fixed on the cache box, a plurality of springs are fixed on the inner upper end of the cache box, a piston plate is fixed on the other end of the spring, the piston plate is slidably connected with the cache box, and a one-way valve is arranged on the flue gas inlet pipe.

[0008] The working principle of the present invention is as follows: the process gas containing SO3 is sent into the flue gas inlet pipe, then enters the buffer box and is intermittently sent into the steam ejector through a valve, and at the same time, the steam inlet sends low-pressure steam into the steam ejector, so that the flue gas and the low-pressure steam are mixed, and then sent into the high-temperature absorption tower through the annular pipe and the outlet pipe. Since the outlet pipe is distributed in an annular manner and the outlet port of the outlet pipe is inclined downward, the mixed gas will not only flow to the bottom of the high-temperature absorption tower to extend the diffusion time of the mixed gas, but also the gas will form a counter-diffusion. During the upward flow of the gas, the sulfuric acid with a temperature of 180°C and a concentration of 99% is sprayed by the second spray absorption system to absorb most of the SO3 in the process gas. The sulfuric acid with a temperature of 60℃ and a concentration of 98.5% sprayed out by the first spray absorption system is absorbed again. After the sulfuric acid absorbs the gas, the temperature rises to 205±15℃. The high-temperature concentrated acid is pressurized by the high-temperature circulating acid pump and sent to the evaporator to heat the low-pressure feed water to produce low-pressure steam. After leaving the evaporator, the acid temperature drops to 190±15℃. After leaving the evaporator, part of the sulfuric acid is sent to the mixer to adjust the sulfuric acid concentration to 99%, and then sent to the second spray absorption system for use. Part of the sulfuric acid is adjusted to 98.5% and then sent to the second spray absorption system for use. The remaining part (10-40%) of the sulfuric acid in the evaporator enters the deoxygenated water heater to preheat the feed water entering the evaporator, and the acid temperature drops to 170±15℃. The remaining sulfuric acid is cooled by the equipment and sent to the deaerator to prepare low-pressure steam and heat the feed water. Finally, the sulfuric acid is sent to the desalted water heater to preheat the desalted water. The steam production rate of this system is generally 0.50 tons of steam / ton of acid. The steam production rate of the sulfuric acid plant using pyrite as raw material is generally 0.25-0.35 tons of steam / ton of acid.

[0009] A slide rod is fixed on the upper side of the piston plate, and the upper end of the slide rod extends out of the buffer box and fixes a limit block.

[0010] With the above structure, during operation, the slide rod can be used to guide and limit the piston plate to prevent the piston plate from deflecting, and the setting of the limit block can limit the descending position of the piston plate to prevent the piston plate from descending below the position where the smoke enters the pipe, thereby ensuring the normal operation of the device.

[0011] A driving gear is fixed on the valve stem of the valve, a sliding sleeve is fixed on the cache box, a sliding column is slidably connected in the sliding sleeve, a rack is fixed at the lower end of the sliding column, the rack is meshed with the gear, a first driven plate and a second driven plate are fixed on the sliding column, and an extrusion rod is fixed on the limit block, and the extrusion rod is located between the first driving rod and the second driving rod.

[0012] When the cam is in a closed position, the valve body is in a closed position, and when the cam is in a closed position, the valve body is in a closed position, and the cam ...

[0013] The first spray absorption system and the second spray absorption system have the same structure, the first spray absorption system includes a spray box, a plurality of air outlets are opened at the upper end of the spray box, a plurality of nozzles are fixed at the lower end of the spray box, a driving motor is fixed at the right end of the spray box, a spoiler tube is rotatably connected inside the spray box, the front and rear sides of the outer wall of the spoiler tube are in contact with the inside of the spray box, a plurality of flow interference holes are opened on the tube wall of the spoiler tube, the spoiler tube is fixedly connected to the output shaft end of the driving motor, and a plurality of air guide tubes are fixed at the lower end of the spray box.

[0014] With the above structure, during operation, the concentrated sulfuric acid in the mixer enters the spoiler tube through the pipeline, and the concentrated sulfuric acid is scattered around due to the rotation of the spoiler tube. At the same time, the flue gas enters the spray box through the air guide pipe, so that the flue gas contacts the scattered concentrated sulfuric acid, increasing the contact surface, thereby improving the absorption effect of the concentrated sulfuric acid on the flue gas.

[0015] The height of the air guide pipe is greater than 2 / 3 of the distance between the spoiler pipe and the lower end of the inner wall of the spray box, the air guide pipe is spaced apart from the spray head, and the air guide pipe is staggered with the spoiler hole.

[0016] With the above structure, a large amount of concentrated sulfuric acid can be prevented from directly entering the air duct during operation, thereby ensuring the smoothness of the air intake of the air duct, and a small amount of concentrated sulfuric acid will be discharged from the air duct, further improving the dispersibility of the concentrated sulfuric acid.

[0017] The spoiler tube is provided with a liquid inlet, and the outer wall of the spoiler tube is rotatably connected with a liquid inlet cover, the liquid inlet is located inside the liquid inlet cover, and the liquid inlet cover is connected with the mixer through a pipeline.

[0018] With the above structure, when the driving motor drives the spoiler tube to rotate, the smooth entry of sulfuric acid can be ensured by the arrangement of the liquid inlet cover and the liquid inlet.

[0019] The deaerator includes a shell, a deaeration chamber and a water supply chamber are provided inside the shell, a hot water storage tank is fixed inside the deaeration chamber, the hot water storage tank is made of heat-conducting material, a flash evaporator is fixed inside the water supply chamber, the water outlet pipe and steam pipe of the flash evaporator are connected to the deaeration chamber, the water supply chamber is connected to the desalted water heater, a treatment tower connected to the deaeration chamber is fixed at the upper end of the shell, and the treatment tower is connected to the steam ejector.

[0020] With the above structure, when the deaerator is working, superheated water enters the hot water storage tank, and the water in the desalted water heater enters the water supply chamber. First, the water in the water supply chamber is flash-evaporated to generate low-pressure steam through the flash evaporator principle, and the water and steam generated by the flash evaporator are sent to the deaerator chamber. On the one hand, the high temperature in the hot water storage tank is used to deoxygenate the desalted water, and on the other hand, the superheated water is used to heat the desalted water and generate steam again, which is convenient for conveying the steam to the steam ejector for use. The structure has good compactness. Compared with the existing deaerator, the height and volume of the deaerator can be greatly reduced, so that the deaerator can be installed and used on the bottom layer, and the heat recycling can be realized to reduce the cost of equipment use.

[0021] A first ventilation pipe is fixed to the outlet end of the steam pipe, the other end of the first ventilation pipe extends into the hot water storage tank and is connected to a heat exchange pipe, the other end of the heat exchange pipe is connected to a second ventilation pipe, the other end of the second ventilation pipe is connected to an air equalizing pipe, and a plurality of air jets are opened on the lower side of the air equalizing pipe.

[0022] With the above structure, during operation, steam can be heat exchanged inside the hot water storage tank through the heat exchange tube to improve the deoxygenation effect, and then discharged downward through the exhaust port of the gas equalizing pipe, thereby extending the deoxygenation time and further improving the deoxygenation effect.

[0023] A driving pipe is fixed at the lower end of the first ventilation pipe, a driven pipe is rotatably connected to the outer periphery of the driving pipe, the other end of the driven pipe is connected to the heat exchange pipe, a plurality of inclined holes are opened on the outer wall of the driving pipe, and a plurality of driving plates are fixed on the inner wall of the driven pipe.

[0024] With the above structure, the steam in the first ventilation pipe enters the driving pipe, is ejected from the inclined hole, and then is sprayed toward the side of the driving plate, thereby driving the driven pipe to rotate under the action of the driving plate, and the driven pipe drives the heat exchange pipe to rotate, stirring the superheated water, thereby improving the heat exchange efficiency. This structure does not require an additional driving mechanism, and does not need to consider the insulation problem of the driving mechanism, which can greatly reduce the cost of use.

[0025] Compared with the existing technology, the low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas has the following advantages:

[0026] 1. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas is equipped with a steam ejector to cope with the large fluctuations in the amount of smelting flue gas and the concentration of sulfur dioxide in the flue gas during the converter blowing process. At the same time, the steam generated by the deaerator is used to send the steam ejector, thereby saving the loss of low-pressure steam and using the excess steam for other purposes.

[0027] 2. The process gas containing SO3 is sent into the flue gas inlet pipe, then into the buffer box and intermittently sent into the steam ejector through the valve. At the same time, the steam inlet sends low-pressure steam into the steam ejector, so that the flue gas and low-pressure steam are mixed, and then sent into the high-temperature absorption tower through the annular pipe and the outlet pipe. Since the outlet pipe is distributed in an annular manner and the outlet of the outlet pipe is inclined downward, the mixed gas will not only flow to the bottom of the high-temperature absorption tower to extend the diffusion time of the mixed gas, but also form counter-diffusion. During the upward flow of the gas, the second spray absorption system is used to spray sulfuric acid with a temperature of 180°C and a concentration of 99% to absorb most of the SO3 in the process gas, and then pass through the first The temperature of the spray absorption system is 60℃, and the sulfuric acid with a concentration of 98.5% is absorbed again. After the sulfuric acid absorbs the gas, the temperature rises to 205±15℃. The high-temperature concentrated acid is pressurized by the high-temperature circulating acid pump and sent to the evaporator to heat the low-pressure feed water to produce low-pressure steam. After leaving the evaporator, the acid temperature drops to 190±15℃. After leaving the evaporator, part of the sulfuric acid is sent to the mixer to adjust the sulfuric acid concentration to 99%, and then sent to the second spray absorption system for use. Part of the sulfuric acid is adjusted to 98.5% and then sent to the second spray absorption system for use. The remaining part (10-40%) of the sulfuric acid in the evaporator enters the deoxygenated water heater to preheat the feed water entering the evaporator, and the acid temperature drops to 170±15℃. The remaining sulfuric acid is cooled by the equipment and sent to the deaerator to prepare low-pressure steam and heat the feed water. Finally, the sulfuric acid is sent to the desalted water heater to preheat the desalted water. The steam production rate of this system is generally 0.50 tons of steam / ton of acid. The steam production rate of the sulfuric acid plant using pyrite as raw material is generally 0.25-0.35 tons of steam / ton of acid.

[0028] 3. The valve is initially in a closed state. When the flue gas inlet pipe sends flue gas containing sulfur dioxide into the buffer box, the air pressure in the buffer box increases, causing the piston plate to compress the spring and move upward, thereby driving the limit block to rise through the sliding rod, and the limit block drives the extrusion rod to rise. When it rises to a certain position, the extrusion rod contacts the first driven plate, thereby driving the first driven plate to rise. The first driven plate drives the rack to rise through the sliding column, and the rack drives the gear to rotate, thereby opening the valve, so that the gas in the buffer box quickly enters the steam ejector under the pressure of the piston plate. When the piston plate drops to a certain extent, the extrusion rod contacts the second driven plate and drives the second driven plate to drop, thereby causing the rack to drop and drive the gear to reverse, close the valve, and stop supplying air to the annular pipe. Such a cycle can realize indirect air supply operation, so that after the flue gas enters the steam ejector, it has enough time to collide and diffuse with the low-pressure steam, so that the flue gas dispersion effect is good, and the flue gas recovery effect is improved.

[0029] 4. During operation, the concentrated sulfuric acid in the mixer enters the spoiler tube through the pipeline, and the concentrated sulfuric acid is scattered around due to the rotation of the spoiler tube. At the same time, the flue gas enters the spray box through the air duct, so that the flue gas contacts the scattered concentrated sulfuric acid, increasing the contact surface, thereby improving the absorption effect of the concentrated sulfuric acid on the flue gas.

[0030] 5. When the deaerator is working, superheated water enters the hot water storage tank, and the water in the desalted water heater enters the water supply chamber. First, the water in the water supply chamber is flash-evaporated to generate low-pressure steam through the principle of the flash evaporator, and the water and steam generated by the flash evaporator are sent to the deaerator chamber. On the one hand, the high temperature in the hot water storage tank is used to deoxygenate the desalted water, and on the other hand, the superheated water is used to heat the desalted water and generate steam again, which is convenient for conveying the steam to the steam ejector for use. The structure has good compactness. Compared with the existing deaerator, it can greatly reduce the height and volume of the deaerator, so that the deaerator can be installed and used at the bottom layer, and it can realize the recycling of heat and reduce the cost of equipment use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a system diagram of the present invention.

[0032] Figure 2 It is a structural schematic diagram of the high temperature absorption tower in the present invention.

[0033] Figure 3 It is a schematic diagram of the structure of the cache box in the present invention.

[0034] Figure 4 It is a structural schematic diagram of the spray absorption system in the present invention.

[0035] Figure 5 yes Figure 4A partial enlarged view of point A in the middle.

[0036] Figure 6 It is a structural schematic diagram of the deaerator in the present invention.

[0037] Figure 7 It is a schematic diagram of the structure of the driving tube and the driven tube in the present invention.

[0038] Figure 8 It is a cross-sectional view of the driving tube and the driven tube in the present invention.

[0039] In the figure, 1, high temperature absorption tower; 2, steam ejector; 3, high temperature circulation tank; 4, high temperature circulation acid pump; 5, evaporator; 6, mixer; 7, deoxygenated water heater; 8, deaerator; 9, desalted water heater; 10, first spray absorption system; 11, second spray absorption system; 12, first packing layer; 13, second packing layer; 14, annular pipe; 15, outlet pipe; 16, inlet pipe; 17, buffer box; 18, flue gas inlet pipe; 19, one-way valve; 20, spring; 21, piston plate; 22, slide rod; 23, limit block; 24, extrusion rod; 25, sliding sleeve; 26, sliding column; 27 , rack; 28, gear; 29, second driven plate; 30, first driven plate; 31, spray box; 32, drive motor; 33, nozzle; 34, air guide tube; 35, spoiler tube; 36, spoiler hole; 37, air outlet; 38, liquid inlet; 39, liquid inlet cover; 40, shell; 41, treatment tower; 42, deaerator chamber; 43, water supply chamber; 44, flash evaporator; 45, water outlet pipe; 46, steam pipe; 47, heat exchange pipe; 48, second ventilation pipe; 49, hot water storage tank; 50, air equalization pipe; 51, first ventilation pipe; 52, drive pipe; 53, inclined hole; 54 driven pipe; 55, drive plate. DETAILED DESCRIPTION

[0040] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0041] like Figure 1-Figure 8As shown, the low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas comprises a high-temperature absorption tower 1, an evaporator 5, a deoxygenated water heater 7, a deaerator 8 and a desalted water heater 9. The high-temperature absorption tower 1 is provided with a first packing layer 12 and a second packing layer 13, a first spray absorption system 10 is provided above the first packing layer 12, and a second spray absorption system 11 is provided above the second packing layer 13. The high-temperature absorption tower 1 is provided with an air inlet, and the lower end of the high-temperature absorption tower 1 is connected to a high-temperature circulation tank 3 through a recovery pipeline. The high-temperature circulation tank 3 is arranged on the pipeline between the packing arranged in the lower layer of the high-temperature absorption tower 1 and the high-temperature circulation acid pump 4, and is used to cooperate in outputting high-temperature gas. The high-temperature circulation tank 3 is connected to the high-temperature circulation acid pump 4 through a pipeline, and the high-temperature circulation acid pump 4 is connected to the sulfuric acid inlet of the evaporator 5 through a pipeline. The first sulfuric acid outlet of the evaporator 5 is connected to the deoxygenated water heater 7, the deaerator 8 and the desalted water in turn. Heater 9, the second sulfuric acid outlet of evaporator 5 is connected with the sulfuric acid inlet of mixer 6, and mixer 6 is connected with the second spray absorption system 11 through a pipeline; the deoxygenated water heater 7 can heat water from 104°C to about 170°C, the desalted water heater 9 can heat the desalted water from room temperature to 104°C, and the temperature of the sulfuric acid discharged from the desalted water heater 9 can be cooled to about 100°C. The deoxygenated water produced in the deaerator 8 meets the low-pressure steam required for SO3 mixing in the flue gas inlet pipe 18 and the deoxygenated water required for use by the evaporator 5. The outlet of the deoxygenated water heater 7 is connected with the inlet of the deaerator heating pipe through a pipeline, and the outlet of the deaerator heating pipe is connected to the hot water pump, and the outlet of the hot water pump is connected to the water supply inlet of the hot water storage tank 49 in the deaerator 8; in addition, the water supply outlet of the deoxygenated water heater 9 is connected with the deoxygenated water inlet of the deaerator 8, and the deoxygenated water outlet of the deaerator is respectively connected to the water inlet of the evaporator 5 and the water inlet of the diluter through the water supply pump.

[0042] The high-temperature absorption tower 1 is provided with a plurality of air inlets distributed in an annular manner, an annular tube 14 is fixed on the outer side of the high-temperature absorption tower 1, a plurality of air outlet pipes 15 are fixed on the inner periphery of the annular tube 14, the air outlet pipes 15 extend into the interior of the high-temperature absorption tower 1 through the air inlet, an air inlet pipe 16 is fixed on the annular tube 14, the other end of the air inlet pipe 16 is connected with the air outlet end of the steam ejector 2, the air inlet end of the steam ejector 2 is connected with the steam inlet, a valve is fixed on the air inlet end of the steam ejector 2, a cache box 17 is fixed on the other end of the valve, a flue gas inlet pipe 18 is fixed on the cache box 17, a plurality of springs 20 are fixed on the inner upper end of the cache box 17, a piston plate 21 is fixed on the other end of the spring 20, the piston plate 21 is slidably connected with the cache box 17, and a one-way valve 19 is provided on the flue gas inlet pipe 18.

[0043] The process gas containing SO3 is sent to the flue gas inlet pipe 18, then enters the buffer box 17 and is intermittently sent to the steam ejector 2 through a valve. At the same time, the steam inlet sends low-pressure steam into the steam ejector 2, so that the flue gas and the low-pressure steam are mixed, and then sent to the high-temperature absorption tower 1 through the annular pipe 14 and the outlet pipe 15. Since the outlet pipe 15 is distributed in an annular manner and the outlet of the outlet pipe 15 is inclined downward, the mixed gas will not only flow to the bottom of the high-temperature absorption tower 1 to extend the diffusion time of the mixed gas, but also the gas will form a counter-diffusion. During the upward flow of the gas, the sulfuric acid with a temperature of 180°C and a concentration of 99% is sprayed by the second spray absorption system 11 to absorb most of the SO3 in the process gas, and then The sulfuric acid with a temperature of 60°C and a concentration of 98.5% sprayed out by the first spray absorption system 10 is absorbed again. After the sulfuric acid absorbs the gas, the temperature rises to 205±15°C. The high-temperature concentrated acid is pressurized by the high-temperature circulating acid pump 4 and sent to the evaporator 5 to heat the low-pressure feed water to produce low-pressure steam. After leaving the evaporator 5, the acid temperature is reduced to 190±15°C. After leaving the evaporator 5, a part of the sulfuric acid is sent to the mixer 6 to adjust the sulfuric acid concentration to 99%, and then sent to the second spray absorption system 11 for use. A part of the sulfuric acid is adjusted to a sulfuric acid concentration of 98.5% and then sent to the second spray absorption system 11 for use. The remaining part (10-40%) of the sulfuric acid in the evaporator 5 is preheated by the deoxygenated water heater 7 of the evaporator 5 and enters the feed water of the evaporator 5. The acid temperature is reduced to 170±15°C. The remaining sulfuric acid is cooled by the equipment and sent to the deaerator 8 to prepare low-pressure steam and heat the feed water. Finally, the sulfuric acid is sent to the desalted water heater 9 to preheat the desalted water. The steam production rate of this system is generally 0.50 tons of steam / ton of acid. The steam production rate of the sulfuric acid plant using pyrite as raw material is generally 0.25-0.35 tons of steam / ton of acid.

[0044] A slide rod 22 is fixed on the upper side of the piston plate 21 , and the upper end of the slide rod 22 extends out of the buffer box 17 and is fixed with a limit block 23 .

[0045] With the above structure, during operation, the slide rod 22 can be used to guide and limit the piston plate 21 to prevent the piston plate 21 from being offset, and the setting of the limit block 23 can limit the descending position of the piston plate 21 to prevent the descending position of the piston plate 21 from being lower than the position of the smoke inlet pipe 18, thereby ensuring the normal operation of the device.

[0046] A driving gear 28 is fixed on the valve stem of the valve, a sliding sleeve 25 is fixed on the cache box 17, a sliding column 26 is slidably connected in the sliding sleeve 25, a rack 27 is fixed to the lower end of the sliding column 26, the rack 27 is meshed with the gear 28, a first driven plate 30 and a second driven plate 29 are fixed on the sliding column 26, and an extrusion rod 24 is fixed on the limit block 23, and the extrusion rod 24 is located between the first driving rod and the second driving rod.

[0047] With the above structure, the valve is initially in a closed state. When the flue gas inlet pipe 18 delivers flue gas containing sulfur dioxide into the buffer box 17, the air pressure in the buffer box 17 increases, causing the piston plate 21 to compress the spring 20 and move upward, thereby driving the limit block 23 to rise through the slide bar 22, and the limit block 23 drives the extrusion rod 24 to rise. When it rises to a certain position, the extrusion rod 24 contacts the first driven plate 30, thereby driving the first driven plate 30 to rise, and the first driven plate 30 drives the rack 27 to rise through the slide column 26, and the rack 27 drives the gear 28 to rotate, thereby closing the valve. Open, so that the gas in the buffer box 17 quickly enters the steam ejector 2 under the pressure of the piston plate 21; when the piston plate 21 drops to a certain extent, the extrusion rod 24 contacts the second driven plate 29 and drives the second driven plate 29 to drop, so that the rack 27 drops and drives the gear 28 to reverse, close the valve, and stop the gas supply to the steam ejector 2. Such a cycle can realize indirect gas supply operation, so that after the flue gas enters the steam ejector 2, it has enough time to collide and diffuse with the low-pressure steam, so that the flue gas dispersion effect is good and the flue gas recovery effect is improved.

[0048] The first spray absorption system 10 and the second spray absorption system 11 have the same structure. The first spray absorption system 10 includes a spray box 31. A plurality of air outlet holes 37 are provided at the upper end of the spray box 31. A plurality of nozzles 33 are fixed to the lower end of the spray box 31. A drive motor 32 is fixed to the right end of the spray box 31. A spoiler tube 35 is rotatably connected to the inside of the spray box 31. The front and rear sides of the outer wall of the spoiler tube 35 are in conflict with the inside of the spray box 31. A plurality of interfering flow holes 36 are provided on the tube wall of the spoiler tube 35. The spoiler tube 35 is fixedly connected to the output shaft end of the drive motor 32. A plurality of air guide tubes 34 are fixed to the lower end of the spray box 31.

[0049] With the above structure, during operation, the concentrated sulfuric acid in the mixer 6 enters the spoiler tube 35 through the pipeline, and the concentrated sulfuric acid is scattered around due to the rotation of the spoiler tube 35. At the same time, the flue gas enters the spray box 31 through the air guide tube 34, so that the flue gas contacts the scattered concentrated sulfuric acid, increasing the contact surface, thereby improving the absorption effect of the concentrated sulfuric acid on the flue gas.

[0050] The height of the air guide pipe 34 is greater than 2 / 3 of the distance between the spoiler pipe 35 and the lower end of the inner wall of the spray box 31 . The air guide pipe 34 is spaced apart from the spray head 33 , and the air guide pipe 34 is staggered with the spoiler hole 36 .

[0051] With the above structure, a large amount of concentrated sulfuric acid can be prevented from directly entering the air duct 34 during operation, thereby ensuring the smoothness of the air intake of the air duct 34, and a small amount of concentrated sulfuric acid will be discharged from the air duct 34, further improving the dispersibility of the concentrated sulfuric acid.

[0052] The spoiler tube 35 is provided with a liquid inlet 38 , and the outer wall of the spoiler tube 35 is rotatably connected with a liquid inlet cover 39 . The liquid inlet 38 is located inside the liquid inlet cover 39 , and the liquid inlet cover 39 is connected with the mixer 6 through a pipeline.

[0053] With the above structure, when the driving motor 32 drives the spoiler tube 35 to rotate, the liquid inlet cover 39 and the liquid inlet 38 can be arranged to ensure smooth entry of sulfuric acid.

[0054] The deaerator 8 includes a shell 40, and a deaerator chamber 42 and a water supply chamber 43 are provided inside the shell 40. A hot water storage tank 49 is fixed inside the deaerator chamber 42, and the hot water storage tank 49 is made of a heat-conducting material. A flash evaporator 44 is fixed inside the water supply chamber 43, and a water outlet pipe 45 and a steam pipe 46 of the flash evaporator 44 are both connected to the deaerator chamber 42. The water supply chamber 43 is connected to the desalted water heater 9. A treatment tower 41 connected to the deaerator chamber 42 is fixed at the upper end of the shell 40, and the treatment tower 41 is connected to the steam ejector 2.

[0055] With the above structure, when the deaerator is working, the superheated water enters the hot water storage tank 49, and the water in the desalted water heater 9 enters the water supply chamber 43. First, the water in the water supply chamber 43 is flashed to generate low-pressure steam through the flash evaporator principle, and the water and steam generated by the flash evaporator 44 are sent to the deoxygenation chamber 42. On the one hand, the high temperature in the hot water storage tank 49 is used to deoxygenate the desalted water, and on the other hand, the superheated water is used to heat the desalted water and generate steam again, which is convenient for conveying the steam to the steam ejector 2 for use. The structure has good compactness. Compared with the existing deaerator, the height and volume of the deaerator can be greatly reduced, so that the deaerator can be installed and used on the bottom layer, and the heat can be recycled to reduce the cost of equipment use.

[0056] A first ventilation pipe 51 is fixed to the air outlet end of the steam pipe 46, the other end of the first ventilation pipe 51 extends into the hot water storage tank 49 and is connected to the heat exchange pipe 47, the other end of the heat exchange pipe 47 is connected to the second ventilation pipe 48, the other end of the second ventilation pipe 48 is connected to the air equalizing pipe 50, and a plurality of air jets are opened on the lower side of the air equalizing pipe 50.

[0057] With the above structure, during operation, steam can be heat exchanged inside the hot water storage tank 49 through the heat exchange tube 47 to improve the deoxygenation effect, and then discharged downward through the exhaust port of the gas equalizing pipe 50, thereby extending the deoxygenation time and further improving the deoxygenation effect.

[0058] A driving tube 52 is fixed to the lower end of the first ventilation tube 51, and a driven tube 54 is rotatably connected to the outer periphery of the driving tube 52. The other end of the driven tube 54 is connected to the heat exchange tube 47. A plurality of inclined holes 53 are opened on the outer wall of the driving tube 52, and a plurality of driving plates 55 are fixed to the inner wall of the driven tube.

[0059] With the above structure, the steam in the first ventilation pipe 51 enters the driving pipe 52, is ejected from the inclined hole 53, and then is sprayed toward the side of the driving plate 55, thereby driving the driven pipe 54 to rotate under the action of the driving plate 55, and the driven pipe 54 drives the heat exchange tube 47 to rotate, stirring the superheated water, thereby improving the heat exchange efficiency. This structure does not require an additional driving mechanism, and does not need to consider the insulation problem of the driving mechanism, which can greatly reduce the cost of use.

[0060] In summary, by setting up structures such as the buffer box 17, the first spray absorption system 10, the second spray absorption system 11 and the deaerator 8, the effect of improving acid production and waste heat recovery and reducing the cost of use are achieved.

[0061] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas, comprising a high-temperature absorption tower (1), an evaporator (5), a deoxygenated water heater (7), a deaerator (8) and a desalted water heater (9), characterized in that: The high-temperature absorption tower (1) is provided with a first packing layer (12) and a second packing layer (13) inside, a first spray absorption system (10) is provided above the first packing layer (12), and a second spray absorption system (11) is provided above the second packing layer (13). An air inlet is provided on the high-temperature absorption tower (1), the lower end of the high-temperature absorption tower (1) is connected to a high-temperature circulation tank (3) via a recovery pipeline, the high-temperature circulation tank (3) is connected to a high-temperature circulation acid pump (4) via a pipeline, the high-temperature circulation acid pump (4) is connected to the sulfuric acid inlet of the evaporator (5) via a pipeline, the first sulfuric acid outlet of the evaporator (5) is connected to the deoxygenated water heater (7), the deoxygenator (8) and the desalted water heater (9) in sequence, the second sulfuric acid outlet of the evaporator (5) is connected to the sulfuric acid inlet of the mixer (6), and the mixer (6) is connected to the second spray absorption system (11) via a pipeline; The high-temperature absorption tower (1) is provided with a plurality of air inlets distributed in an annular shape. An annular tube (14) is fixed on the outer side of the high-temperature absorption tower (1). A plurality of air outlet pipes (15) are fixed on the inner circumference of the annular tube (14). The air outlet pipes (15) extend into the interior of the high-temperature absorption tower (1) through the air inlet. An air inlet pipe (16) is fixed on the annular tube (14). The other end of the air inlet pipe (16) is connected to the air outlet end of the steam ejector (2). The air inlet end of the steam ejector (2) is connected to the steam inlet. A valve is fixed on the air inlet end of the steam ejector (2). A buffer box (17) is fixed on the other end of the valve. A flue gas inlet pipe (18) is fixed on the buffer box (17). A plurality of springs (20) are fixed on the upper end of the interior of the buffer box (17). A piston plate (21) is fixed on the other end of the spring (20). The piston plate (21) is slidably connected to the buffer box (17). A one-way valve (19) is provided on the flue gas inlet pipe (18). The deaerator (8) comprises a shell (40), wherein a deaerator chamber (42) and a water supply chamber (43) are provided inside the shell (40), a hot water storage tank (49) is fixed inside the deaerator chamber (42), and the hot water storage tank (49) is made of a heat-conducting material, a flash evaporator (44) is fixed inside the water supply chamber (43), a water outlet pipe (45) and a steam pipe (46) of the flash evaporator (44) are both connected to the deaerator chamber (42), the water supply chamber (43) is connected to the desalted water heater (9), a treatment tower (41) connected to the deaerator chamber (42) is fixed at the upper end of the shell (40), the treatment tower (41) is connected to the steam ejector (2), and the gas outlet end of the steam pipe (46) is connected to the steam ejector (2). A first ventilation pipe (51) is fixed, the other end of the first ventilation pipe (51) extends into the hot water storage tank (49) and is connected to the heat exchange pipe (47), the other end of the heat exchange pipe (47) is connected to the second ventilation pipe (48), the other end of the second ventilation pipe (48) is connected to the air equalizing pipe (50), a plurality of air jets are provided on the lower side of the air equalizing pipe (50), a driving pipe (52) is fixed to the lower end of the first ventilation pipe (51), the outer periphery of the driving pipe (52) is rotatably connected to a driven pipe, the other end of the driven pipe is connected to the heat exchange pipe (47), a plurality of inclined holes (53) are provided on the outer wall of the driving pipe (52), and a plurality of driving plates (55) are fixed to the inner wall of the driven pipe (54).

2. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas according to claim 1 is characterized in that: A slide rod (22) is fixed on the upper side of the piston plate (21), and the upper end of the slide rod (22) extends out of the buffer box (17) and is fixed with a limit block (23).

3. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas according to claim 2 is characterized in that: A driving gear (28) is fixed on the valve stem of the valve, a sliding sleeve (25) is fixed on the buffer box (17), a sliding column (26) is slidably connected in the sliding sleeve (25), a rack (27) is fixed at the lower end of the sliding column (26), the rack (27) is meshed with the gear (28), a first driven plate (30) and a second driven plate (29) are fixed on the sliding column (26), and an extrusion rod (24) is fixed on the limit block (23), and the extrusion rod (24) is located between the first driving rod and the second driving rod.

4. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas according to claim 1 is characterized in that: The first spray absorption system (10) and the second spray absorption system (11) have the same structure. The first spray absorption system (10) comprises a spray box (31). A plurality of air outlet holes (37) are provided at the upper end of the spray box (31). A plurality of spray heads (33) are fixed at the lower end of the spray box (31). A driving motor (32) is fixed at the right end of the spray box (31). A spoiler tube (35) is rotatably connected to the inside of the spray box (31). Both the front and rear sides of the outer wall of the spoiler tube (35) are in contact with the inside of the spray box (31). A plurality of flow interference holes (36) are provided on the tube wall of the spoiler tube (35). The spoiler tube (35) is fixedly connected to the output shaft end of the driving motor (32). A plurality of air guide tubes (34) are fixed to the lower end of the spray box (31).

5. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas according to claim 4 is characterized in that: The height of the air guide pipe (34) is greater than 2 / 3 of the distance between the spoiler pipe (35) and the lower end of the inner wall of the spray box (31), the air guide pipe (34) and the spray head (33) are arranged at intervals, and the air guide pipe (34) and the spoiler hole (36) are arranged in a staggered manner.

6. The low-temperature waste heat recovery system for acid production from non-ferrous smelting flue gas according to claim 4 is characterized in that: The spoiler tube (35) is provided with a liquid inlet (38), and the outer wall of the spoiler tube (35) is rotatably connected to a liquid inlet cover (39). The liquid inlet (38) is located inside the liquid inlet cover (39), and the liquid inlet cover (39) is connected to the mixer (6) through a pipeline.

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