An apparatus and method for the low temperature spray drying of a suspension of particles in a three phase concentrate

Abstract

The application discloses a kind of equipment and method for treating concentrated liquid of three-phase low-temperature spray drying of suspended particles, including particle supply system, low-temperature gas supply air system, turbulent air field mixing system, liquid atomization system, laminar flow air field mixing system, suspended particle system, particle collection discharge system and gas-solid separation, condensate recovery and tail gas deodorization system;Particle supply system and low-temperature gas supply air system provide particles and low-temperature gas respectively;Turbulent air field mixing system realizes low-temperature gas turbulence;The upper portion of tapered cylinder is provided with liquid atomization system to atomize concentrated liquid into droplets;The upper portion of tapered cylinder is provided with laminar flow air field mixing system, and the turbulent flow state of gas-liquid mixed fluid is adjusted to laminar flow state;Laminar flow air field mixing system is provided with suspended particle system above it.The present application realizes the efficient separation of soluble substances in concentrated liquid through the dual action of evaporation and interception of suspended particle layer droplets, and opens up a new technical route for the spray drying treatment of concentrated liquid.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental engineering water treatment technology and spray drying technology, and in particular to a device and method for treating concentrated liquid by low-temperature drying of suspended particles. BACKGROUND

[0002] The membrane concentrated liquid of landfill leachate and the concentrated liquid generated by zero discharge of industrial enterprise wastewater in China have large production, which are two types of concentrated liquid that need to be treated urgently at present. The various types of concentrated liquid have complex components, high salt content and difficult degradation, which are worldwide problems in wastewater treatment.

[0003] At present, the concentrated liquid treatment technology mainly includes evaporation concentration, such as multi-effect evaporation (MED), steam-powered compression evaporation (TVR), mechanical compression evaporation (MVR), flash evaporation (FE), submerged combustion evaporation (SCE) and other evaporation technologies. As a reduction treatment method, evaporation treatment can reduce the volume of the original membrane concentrated liquid to 2-10%; however, due to the presence of a large amount of ammonia nitrogen, organic matter, scaling ions and chloride ions in the concentrated liquid, high-temperature corrosion and container scaling are prone to occur, and therefore the evaporation technology faces problems such as high investment, high operation and maintenance cost and poor stability.

[0004] Spray drying technology is widely used in food, medicine and chemical industries, and is used for product drying, powder preparation and solid-liquid separation. The technology uses an atomizer to disperse the raw material liquid into mist droplets, and dries the mist droplets by hot gas to obtain the product. Spray drying has the advantages of fast drying speed, high drying efficiency, flexible operation and strong adaptability, but the spray drying technology is greatly affected by gas temperature, and the heat transfer coefficient will also be low when the temperature is low, resulting in low thermal efficiency.

[0005] In summary, how to overcome the shortcomings of the existing concentrated liquid evaporation technology and spray drying technology, combine the advantages of the two, and efficiently utilize the characteristics of high salt content and high ammonia nitrogen of the concentrated liquid, is a technical problem that needs to be solved in the prior art. SUMMARY

[0006] In order to solve the above problems, the present application provides a device and method for treating concentrated liquid by low-temperature spray drying of suspended particles.

[0007] The technical scheme of the present application is as follows:

[0008] A device for treating concentrated liquid by low-temperature spray drying of suspended particles, comprising a particle feeding system, a low-temperature gas supply and distribution system, a turbulent flow field mixing system, a liquid atomization system, a laminar flow field mixing system, a suspended particle system, a particle collection and discharge system, and a gas-solid separation, condensed water recovery and tail gas deodorization system.

[0009] The particle supply system and the low-temperature gas supply system are respectively located at the upper and lower ends of the device, and respectively provide particles and low-temperature gas;

[0010] The turbulent flow field mixing system comprises a tapered cylinder with a large lower part and a small upper part, so as to realize turbulent flow of the low-temperature gas; the upper part of the tapered cylinder is provided with the liquid atomization system, which atomizes the concentrated liquid into atomized droplets and fully mixes the atomized droplets with the turbulent low-temperature gas into a gas-liquid two-phase mixed fluid; the upper part of the tapered cylinder is provided with the laminar flow field mixing system, which adjusts the turbulent flow state of the gas-liquid mixed fluid into a laminar flow state.

[0011] The laminar flow field mixing system is provided above the suspended particle system, and the atomized droplets of the concentrated liquid collide with the suspended particles to be absorbed and rapidly evaporated.

[0012] Further, the suspended particle system utilizes the balance between the gravity of the particles and the resistance formed by the relative motion of the gas-liquid mixed fluid and the particles to form a stable suspended particle layer.

[0013] Further, the tapered cylinder is provided with the particle collection and discharge system, and the particle collection system comprises a discharge hopper with a large lower part and a small upper part; the diameter of the tapered cylinder is gradually reduced, and the diameter of the discharge hopper is gradually increased, so as to hinder the turbulent flow of the low-temperature gas; the contraction angle of the tapered cylinder is 30-60°.

[0014] Further, the liquid atomization system comprises a concentrated liquid conveying pipe and an atomizing nozzle connected with each other.

[0015] Further, the laminar flow field mixing system comprises a flow regulating assembly, and the flow regulating assembly adopts a vane type, a hole plate type or a vane-hole plate combined type gas flow regulator.

[0016] Further, the gas-solid separation, condensate water recovery and tail gas deodorization system is located at the upper part of the device and comprises a cyclone separator, a water collector, a condenser and a subsequent deodorization system connected in sequence.

[0017] Further, the particle supply system comprises a screw conveyor and a vibrating hole plate, and the vibrating hole plate is used for uniform distribution; the low-temperature gas supply system comprises an air inducing fan and a wind distribution hole plate, and the wind distribution hole plate is used for uniform air supply.

[0018] A method for processing concentrated liquid by using the above-mentioned device for processing concentrated liquid by using a suspended particle three-phase low-temperature spray drying process, comprising the following steps:

[0019] Light particles are uniformly distributed from the top of the device by using the particle supply system;

[0020] Low-temperature tail gas is uniformly distributed upward from the bottom of the device by using the low-temperature gas supply system.

[0021] The turbulent wind field mixing system forms a turbulent wind field when the low-temperature hot air diffuses upward, and the turbulent wind field is rapidly and fully mixed with the concentrated liquid atomized droplets to form a gas-liquid two-phase mixed fluid;

[0022] The gas-liquid two-phase mixed fluid continues to enter the laminar flow field mixing system upward to adjust the turbulent flow state to a laminar flow state;

[0023] The mixed fluid in the laminar flow state uniformly and balancedly enters the suspended particle system to form a gas-liquid-solid three-phase mixed fluid, wherein the concentrated liquid atomized droplets collide with the suspended particles to be intercepted, absorbed and rapidly evaporated; the suspended particles enriched with salt and residual liquid increase in weight and then lose stability to fall into the particle collection and discharge system for discharge.

[0024] Further, the low-temperature tail gas includes low-temperature coal-fired tail gas and low-temperature industrial tail gas, and the temperature of the tail gas is 50-100 DEG C; the concentrated liquid is landfill leachate membrane concentrated liquid or concentrated liquid generated in industrial enterprise sewage zero discharge engineering.

[0025] Further, the suspended particles are calcium-carbon-based mesoporous particles, and the mesoporous pore size is 18-20 nm; the particle size of the suspended particles is 3-5 mm.

[0026] Further, the upward escaping gas-liquid-solid three-phase mixed fluid enters the gas-solid separation, condensed water recovery and tail gas deodorization system to realize gas-solid separation, the solid particles fall into the discharge bin for discharge, the escaping droplets are physically recovered into concentrated liquid by using a water collector, the water vapor is recycled after being recovered by a condenser, and the tail gas is discharged after being deodorized.

[0027] The beneficial effects of the present application are as follows:

[0028] (1) The present application overcomes the shortcomings of existing concentrated liquid evaporation technology, such as high-temperature corrosion and container fouling, and the shortcomings of spray drying technology, such as being greatly affected by gas temperature and low thermal efficiency, combines the advantages of the two, reduces container fouling through the interception of suspended particles, improves the low thermal efficiency by using low-temperature coal-fired tail gas, and also efficiently utilizes the high salt content and high ammonia nitrogen characteristics of concentrated liquid to realize low-temperature spray drying technology of concentrated liquid.

[0029] (2) The present application has a clever device concept and reasonable design; the design of each subsystem is an invention point, such as the gas and liquid entering the device from the bottom instead of from the top of the traditional spray dryer, the full mixing of gas and liquid by the turbulent wind field mixing system, the conversion of the flow state to laminar flow by the rectifying assembly of the laminar flow field mixing system to ensure the stability of the suspended particle layer.

[0030] (3) The present application sets up a suspended particle layer in the device, realizes the efficient separation of dissolved substances in the concentrated liquid through the dual action of droplet evaporation and interception of the suspended particle layer, and opens up a new technical route for the spray drying treatment of concentrated liquid.

[0031] (4) The present application preferably uses coal-fired tail gas as a gas source, which can utilize low-grade heat energy and fix part of carbon dioxide (CO2) in the coal-fired tail gas, thereby being beneficial to carbon emission reduction of the coal-fired tail gas.

[0032] (5) The raw material liquid of the present application uses concentrated liquid, such as landfill leachate membrane concentrated liquid or concentrated liquid generated in industrial enterprise sewage zero discharge engineering, to realize pollution-free resource treatment.

[0033] In summary, the present application can realize cross-media removal of pollutants in gas-liquid-solid three phases, and simultaneously realize harmless, reduction and resource of gas-liquid-solid waste. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic diagram of the present application of the suspended particle three-phase low-temperature spray drying equipment;

[0035] Among them, 1 is a low-temperature gas inlet, 2 is a wind distribution hole plate, 3 is a concentrated liquid conveying pipe, 4 is an atomizing nozzle, 5 is a first screw conveyor, 6 is a vibrating hole plate, 7 is an outlet hopper, 8 is a rotary on-off device, 9 is a second screw conveyor, 10 is a suspended particle layer, 11 is a rectifying section cylinder, 12 is a rectifying assembly, 13 is a mixing section cylinder, 14 is a tapered section cylinder, 15 is a cyclone separator, 16 is a water collector, and 17 is a condenser. DETAILED DESCRIPTION

[0036] In order to make the technical means, creative features, purposes and effects realized by the present application easy to understand, the technical solutions in the embodiments of the present application are described clearly and completely below in combination with the drawings of the specification. It should be understood that the described embodiments are only part of the embodiments of the present application, not all.

[0037] The equipment for processing concentrated liquid by the suspended particle three-phase low-temperature spray drying in the present embodiment includes eight subsystems: a screw conveying particle feeding system, a low-temperature gas supply and distribution system, a turbulent air field mixing system, a liquid atomizing system, a laminar air field mixing system, a suspended particle system, a particle collection and discharge system, and a gas-solid separation, condensed water recovery and tail gas deodorization system.

[0038] Among them, the screw conveying particle feeding system is located at the top of the equipment, including the first screw conveyor 5 and the vibrating hole plate 6, and uniform feeding is realized through the vibrating hole plate 6. The hole diameter of the vibrating hole plate 6 is 5-10 mm.

[0039] Among them, the low-temperature gas supply and distribution system is located at the bottom of the equipment, including an air supply fan and the wind distribution hole plate 2, and the low-temperature gas is supplied through the wind distribution hole plate 2 to realize uniform distribution of temperature and wind speed. The low-temperature gas is low-temperature coal-fired tail gas, and the hole diameter of the wind distribution hole plate 2 is 10-50 mm.

[0040] The turbulent wind field mixing system is mainly composed of a tapered section cylinder 14, including a mixing section cylinder 13 and the tapered section cylinder 14, the mixing section cylinder 13 is located above the tapered section cylinder 14 and the two are communicated, the diameter of the tapered section cylinder 14 is gradually reduced Figure 1 The diameter of the tapered section cylinder 14 is gradually reduced and the diameter of the discharge hopper 7 located in the system is gradually increased to hinder the disturbance of the wind field to achieve the purpose of fluid turbulence, and the contraction angle of the tapered section cylinder 14 is 30-60°.

[0041] The liquid atomization system is located in the mixing area (specifically the mixing section cylinder 13) above the turbulent wind field mixing system, including a concentrated liquid delivery pipe 3 and an atomizing nozzle 4 connected with each other. The atomizing nozzle 4 atomizes the concentrated liquid into small atomized droplets which are released and fully mixed with the low-temperature gas in the turbulent flow state to form a gas-liquid two-phase mixed fluid.

[0042] The laminar wind field mixing system is mainly composed of a flow regulating assembly 12, including a flow regulating section cylinder 11 and the flow regulating assembly 12, the flow regulating section cylinder 11 is located above the mixing section cylinder 13 and the two are communicated, the flow regulating assembly 12 is arranged in the flow regulating section cylinder 11, and the flow regulating assembly 12 is used to adjust the mixed fluid in the turbulent flow state to the laminar flow state, so that the mixed fluid can enter the suspended particle system uniformly and balancedly.

[0043] Further, the flow regulating assembly adopts a common blade type, hole plate type or blade-hole plate combined type gas flow regulator, and specifically can refer to the flow regulator part of 6.3 and appendix B in GB / T2624.2-2006.

[0044] The suspended particle system includes a suspended particle layer 10 located above the flow regulating section cylinder 11, and the stable suspended particle layer 10 is formed by balancing the particle settling velocity of the suspended particle layer 10 and the upward flow velocity of the mixed fluid, i.e. balancing the gravity of the particles and the resistance formed by the relative motion of the mixed fluid and the particles.

[0045] The particle collection and discharge system is located in the tapered section cylinder 14 of the turbulent wind field mixing system, including a discharge hopper 7, a rotary on-off device 8 and a second screw conveyor 9 connected in sequence, Figure 1 The discharge hopper 7 is large at the top and small at the bottom, which is convenient for receiving the falling suspended particles; the suspended particles fall to the discharge hopper 7 due to the enrichment of salt and the weight increase of residual liquid, and the collection and discharge of particles are completed, and the low-temperature gas is prevented from being discharged.

[0046] The gas-liquid-solid mixture escapes upward into the cyclone separator 15 to realize separation of the gas and the solid particles under the action of centrifugal force. The separated wet hot gas enters the water collector 16 to recover a large amount of fine concentrated liquid droplets entrained in the hot air. The recovered concentrated liquid is returned to the system for re-atomization absorption, and the gas enters the condenser 17 for further condensation to obtain condensed water. Finally, the dry gas is discharged after being treated by the deodorization system, and the separation and treatment of the gas-liquid-solid mixture are completed.

[0047] The method for treating the concentrated liquid by using the above-mentioned equipment for treating the concentrated liquid by low-temperature spray drying of suspended particles includes the following steps:

[0048] The light particles are added from the top of the equipment by using a spiral conveying feeding system, and uniform feeding is realized through the vibrating hole plate 6.

[0049] The low-temperature coal-fired tail gas is introduced from the low-temperature gas inlet 1 at the bottom of the equipment by using a low-temperature gas supply and distribution system, and uniform gas distribution is realized through the air distribution hole plate 2.

[0050] When the low-temperature hot air diffuses upward, it forms a turbulent flow field (turbulent flow state) by being hindered and tapered by the discharge hopper 7 and the section cylinder 14, and the concentrated liquid atomized droplets released by the atomizing nozzle 4 are quickly mixed to form a gas-liquid two-phase mixed fluid.

[0051] The gas-liquid two-phase mixed fluid continues to enter the laminar flow field mixing system upward, and the rectifier assembly 12 is used to adjust the turbulent flow state to a laminar flow state.

[0052] The mixed fluid in the laminar flow state enters the suspended particle layer 10 to form a gas-liquid-solid three-phase mixed fluid, in which the concentrated liquid atomized droplets are quickly absorbed and evaporated after colliding with the suspended particles.

[0053] The suspended particles, which are enriched with salt and residual liquid and become unstable, fall into the discharge hopper 7, and then are discharged through the second spiral conveyor 9 after being locked by the rotary on-off device 8.

[0054] The upward escaping gas-liquid-solid three-phase mixed fluid enters the cyclone separator 15 to realize gas-solid separation, and the solid particles fall into the discharge bin for discharge. The escaping liquid droplets are physically recovered to concentrated liquid by using the water collector 16, and the water vapor is recovered and reused by using the condenser 17. The tail gas is discharged after being deodorized.

[0055] Further, the low-temperature coal-fired tail gas can be replaced by other low-temperature industrial tail gas, and the gas temperature is preferably 50-100°C.

[0056] Further, the concentrated liquid is preferably a landfill leachate membrane concentrated liquid or a concentrated liquid generated in a zero discharge project of industrial enterprise wastewater, and the like.

[0057] Further, the atomized droplets released by the atomizing nozzle 4 have a diameter of 10-200 μm.

[0058] Further, the suspended particles are preferably calcium-carbon-based mesoporous particles, and the particle size of the suspended particles is preferably 3-5 mm.

[0059] Further, the calcium-carbon-based mesoporous particles can be prepared by the following method:

[0060] (1) The aquaculture pond sediment, calcium carbide slag and straw powder are stirred and mixed; the mass ratio of the sediment, calcium carbide slag and straw powder is (5-6):2:(2-3);

[0061] (2) The mixed material is dewatered and pressure-formed in a double-screw extruder to form wet-based columnar particles;

[0062] (3) The wet-based columnar particles are sent to a low-temperature aerobic pyrolysis rotary reactor (the low-temperature aerobic pyrolysis rotary reactor is a horizontal rotary aerobic pyrolysis furnace described in CN115477527B), and the particles are preheated, low-temperature aerobic pyrolyzed and instantaneously combusted to realize the harmless treatment of the aquaculture pond sediment, and obtain calcium-carbon-based particles with particle strength (calcium carbonate formed by the reaction of CO2 generated by pyrolysis and CO2 in the atmosphere with the calcium carbide slag provides particle strength for the columnar particles), and having a mesoporous space structure (average pore size of 20 nm). The good mesoporous system of the calcium-carbon-based particles can be used as a spray drying carrier. That is, the above-mentioned calcium-carbon-based mesoporous particles. It has a large porosity and specific surface area (such as a specific surface area of 13.6764 m 2 / g).

[0063] Alternatively, the calcium-carbon-based mesoporous particles can also be prepared by the following method:

[0064] (1) The sewage sludge, calcium carbide slag and fly ash are stirred and mixed; the mass ratio of the sewage sludge, fly ash and calcium carbide slag is (3-4):(1-1.5):(1-2);

[0065] (2) The above mixture is conveyed to a double-screw extruder to obtain wet-based columnar particles by pressure forming, and the water content is 40-50%;

[0066] (3) The wet base columnar particles are sent to a low-temperature aerobic pyrolysis rotary reactor (the low-temperature aerobic pyrolysis rotary reactor is a horizontal rotary aerobic pyrolysis furnace described in CN115477527B); the wet base columnar particles are preheated in front of the reactor by using tail gas waste heat to reduce the water content of the particles to 20-30%; in the low-temperature aerobic pyrolysis zone in the middle of the reactor, the biomass contained in the sewage sludge is subjected to aerobic pyrolysis to form biochar, and at the same time, the carbide slag reacts with CO2 in the environment or CO2 generated by pyrolysis to directly form calcium carbonate to provide mechanical strength to the particles; at the end of the reactor, the surface liquid phase product is removed by instantaneous combustion; and finally, calcium-carbon-based biochar ceramsite (mesoporous average pore diameter of 18 nm) with high mechanical strength and without maintenance is formed, i.e., the calcium-carbon-based mesoporous particles described above. It has a larger porosity and specific surface area (such as a specific surface area of 16.2173 m 2 / g).

[0067] Example 1

[0068] The equipment for the three-phase low-temperature spray drying treatment of the concentrated liquid of the suspended particles in this embodiment, whose treatment object is the high-concentration concentrated liquid, landfill leachate membrane concentrated liquid, mainly includes eight subsystems: a spiral conveying particle feeding system, a low-temperature gas air supply system, a turbulent air field mixing system, a liquid atomization system, a laminar air field mixing system, a suspended particle system, a particle collection and discharge system, and a gas-solid separation, condensed water recovery and tail gas deodorization system.

[0069] Among them, the spiral conveying particle feeding system is located at the top of the equipment, including a first spiral conveyor 5 and a vibrating aperture plate 6, which realizes uniform feeding through the vibrating aperture plate 6. The aperture diameter of the vibrating aperture plate 6 is 4 mm.

[0070] Among them, the low-temperature gas air supply system is located at the bottom of the equipment, including an air induction fan and an air distribution aperture plate 2. The low-temperature gas is supplied through the air distribution aperture plate 2 to realize uniform distribution of temperature and air speed. The low-temperature gas is preferentially coal-fired tail gas. The aperture diameter of the air distribution aperture plate 2 is 30 mm.

[0071] Among them, the turbulent air field mixing system includes a mixing section cylinder 13 and a tapered section cylinder 14. The purpose of fluid turbulence is achieved by gradually reducing the diameter of the tapered section cylinder 14 and the discharge hopper 7 located in the system to disturb the air field. The contraction angle of the tapered section cylinder 14 is 60°.

[0072] Among them, the liquid atomization system is located in the mixing zone above the turbulent air field mixing system, including a concentrated liquid conveying pipe 3 and an atomizing nozzle 4 connected to each other. The atomizing nozzle 4 atomizes the liquid into tiny atomized droplets, which are released and fully mixed with the low-temperature gas in turbulent flow to form a gas-liquid two-phase mixed fluid.

[0073] The laminar flow field mixing system is mainly composed of a rectifying component 12, which adjusts the turbulent flow state of the mixed fluid to a laminar flow state.

[0074] The suspended particle system is composed of a suspended particle layer 10, which is formed by balancing the particle sedimentation speed and the rising flow speed of the mixed fluid, i.e. balancing the particle gravity and the resistance formed by the relative motion between the mixed fluid and the particles.

[0075] The particle collection and discharge system is located in the tapered section cylinder 14 of the turbulent flow field mixing system, and is composed of a discharge hopper 7, a rotary on-off device 8 and a screw conveyor 9. The suspended particles fall to the discharge hopper 7 due to the enrichment of salt and the increase in weight of the residual liquid, and the collection and discharge of the particles are completed, while preventing the discharge of low-temperature gas.

[0076] The gas-solid separation, condensate water recovery and tail gas deodorization system is located at the upper part of the equipment, and is composed of a cyclone separator 15, a water collector 16, a condenser 17 and a subsequent deodorization system. The escaped gas-liquid-solid mixture enters the cyclone separator 15 and is separated into wet hot gas and particles due to the action of centrifugal force. The separated wet hot gas enters the water collector 16 to recover a large number of fine concentrated liquid droplets entrained in the hot air. The recovered concentrated liquid is returned to the system for re-atomization and absorption, while the gas enters the condenser 17 for further condensation to obtain condensate water. Finally, the dry gas is discharged after being treated by the deodorization system, and the separation and treatment of the gas-liquid-solid mixture are completed.

[0077] The method for processing concentrated liquid by using the above-mentioned suspended particle three-phase low-temperature spray drying equipment for processing concentrated liquid includes the following steps:

[0078] The light calcium carbonate-based mesoporous particles with a particle size of 4 mm (prepared by any one of the preparation methods in Example 1 above) are fed from the top of the device using a screw conveying feeding system, and uniform feeding is achieved by vibrating the hole plate 6; the low-temperature coal combustion tail gas at 70°C is introduced from the low-temperature gas inlet 1 at the bottom of the device through the warm gas supply and distribution system, and uniform gas distribution is achieved by the bottom air distribution hole plate 2; the low-temperature hot air passes through the discharge hopper 7 and the tapered section cylinder 14 to form a turbulent wind field, and the 50 μm diameter liquid droplets of the landfill leachate membrane concentrate released by the atomizing nozzle 4 are quickly mixed to form a gas-liquid two-phase mixed fluid; the gas-liquid two-phase mixed fluid continues to enter the laminar flow field rectification system, and the turbulent flow state is adjusted to a laminar flow state by using the rectification assembly 12; the laminar mixed fluid enters the suspended particle layer 10 to form a gas-liquid-solid three-phase mixing system, and the atomized droplets are absorbed and quickly evaporated after colliding with the suspended particles; the suspended particles enriched with salt and residual liquid increase in weight and then lose stability to fall into the particle collection hopper 7, and after the air is locked and discharged by the rotary air lock 8, it is discharged through the second screw conveyor 9; the gas-liquid-solid mixture that escapes upward enters the cyclone separator 15 to achieve gas-solid separation, wherein the solid particles fall into the discharge bin and are discharged, the escaping droplets are physically recovered to concentrate liquid by using the water collector 16, and the water vapor is recovered by using the condenser 17 and then reused, and the tail gas is discharged after deodorizing treatment.

[0079] Example 2:

[0080] The suspended particle three-phase low-temperature spray drying treatment concentrate device of the present embodiment is aimed at the treatment object of high-concentration concentrate—landfill leachate membrane concentrate, and mainly includes eight subsystems: a screw conveying particle feeding system, a low-temperature gas supply and distribution system, a turbulent wind field mixing system, a liquid atomizing system, a laminar flow field mixing system, a suspended particle system, a particle collection and discharge system, and a gas-solid separation, condensate recovery and tail gas deodorization system.

[0081] The screw conveying particle feeding system is located at the top of the device, and includes a screw conveyor 5 and a vibrating hole plate 6, and uniform feeding is achieved by vibrating the hole plate 6, and the hole diameter of the multi-hole plate is 5 mm.

[0082] The low-temperature gas supply and distribution system is located at the bottom of the device, and includes an air supply fan and an air distribution hole plate 2, and the low-temperature gas is supplied through the air distribution hole plate 2 to achieve uniform distribution of temperature and air speed, and the low-temperature gas is preferably coal combustion tail gas, and the hole diameter of the multi-hole plate is 50 mm.

[0083] The turbulent wind field mixing system is mainly composed of a tapered pipe 14, including a mixing section cylinder 13 and a tapered section cylinder 14, and the purpose of fluid turbulence is achieved by gradually reducing the diameter of the tapered section cylinder 14 and the discharge hopper 7 located in the system to disturb the wind field, and the contraction angle of the tapered section cylinder 14 is 40°.

[0084] The liquid atomization system is located above the mixing area of the turbulent wind field mixing system, and comprises a concentrated liquid delivery pipe 3 and an atomization nozzle 4 connected with each other, the atomization nozzle 4 atomizes the liquid into small atomized droplets which are released and fully mixed with the low-temperature gas in a turbulent flow state to form a gas-liquid two-phase mixed fluid.

[0085] The laminar wind field mixing system is mainly composed of a flow regulating assembly 12, and the flow regulating assembly 12 is used to adjust the mixed fluid in a turbulent flow state to a laminar flow state.

[0086] The suspended particle system is composed of a suspended particle layer 10, and the suspended particle layer 10 is formed by balancing the particle sedimentation speed and the upward flow speed of the mixed fluid, i.e. balancing the gravity of the particles and the resistance formed by the relative motion between the mixed fluid and the particles.

[0087] The particle collection and discharge system is located in the tapered section cylinder 14 of the turbulent wind field mixing system, and is composed of a discharge hopper 7, a rotary on-off device 8 and a screw conveyor 9, the suspended particles fall to the discharge hopper 7 due to the enrichment of salt and the increase in weight of residual liquid, and the collection and discharge of the particles are completed, and the low-temperature gas is prevented from being discharged.

[0088] The gas-solid separation, condensate water recovery and tail gas deodorization system is located at the upper part of the equipment, and is composed of a cyclone separator 15, a water collector 16, a condenser 17 and a subsequent deodorization system. The escaped gas-liquid-solid mixture enters the cyclone separator 15 and is separated into wet hot gas and particles due to the action of centrifugal force, the separated wet hot gas enters the water collector 16 to recover a large amount of fine concentrated liquid droplets entrained in the hot air, the recovered concentrated liquid is returned to the system for atomization absorption again, the gas enters the condenser 17 for further condensation to obtain condensate water, and finally the dry gas is discharged after being treated by the deodorization system, and the separation and treatment of the gas-liquid-solid mixture are completed.

[0089] The method for processing concentrated liquid by using the above-mentioned suspended particle three-phase low-temperature spray drying device for processing concentrated liquid comprises the following steps:

[0090] The light calcium carbonate-based mesoporous particles with a particle size of 5 mm (prepared by any one of the preparation methods in Embodiment 1 above) are fed from the top of the device by using a screw conveying feeding system, and are uniformly distributed by the vibrating hole plate 6; the low-temperature coal combustion tail gas at 50°C is introduced from the low-temperature gas inlet 1 at the bottom of the device by using the air supply and distribution system, and is uniformly distributed by the bottom air distribution hole plate 2; the low-temperature hot air passes through the discharge hopper 7 and the tapered section cylinder 14 to form a turbulent air field, and the 70 μm diameter liquid droplets of the landfill leachate membrane concentrate released by the atomizing nozzle 4 are quickly mixed to form a gas-liquid two-phase mixed fluid; the gas-liquid two-phase mixed fluid continues to move upward into the laminar flow field rectification system, and the turbulent flow state is adjusted to a laminar flow state by using the rectification assembly 12; the laminar mixed fluid enters the suspended particle layer 10 to form a gas-liquid-solid three-phase mixing system, and the atomized liquid droplets are quickly absorbed and evaporated after colliding with the suspended particles; the suspended particles enriched with salt and residual liquid are increased in weight and then lose stability to fall into the particle collection hopper 7, and after the air is locked and discharged by the rotary air lock 8, they are discharged by the second screw conveyor 9; the gas-liquid-solid mixture that escapes upward in the mixing system enters the cyclone separator 15 to realize gas-solid separation, wherein the solid particles fall into the discharge bin and are discharged, the escaped liquid droplets are physically recycled to concentrate liquid by using the water collector 16, the water vapor is recycled by using the condenser 17 and then reused, and the tail gas is discharged after being deodorized.

[0091] The above description does not constitute a limitation on the protection scope of the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. An apparatus for the three-phase low-temperature spray drying of a concentrate of a suspension of particles, characterized in that The device comprises a particle supply system, a low-temperature gas supply system, a turbulent air field mixing system, a liquid atomization system, a laminar air field mixing system, a suspended particle system, a particle collection and discharge system, and a gas-solid separation, condensed water recovery and tail gas deodorization system. The particle supply system and the low-temperature gas supply system are respectively located at the upper and lower ends of the device, and respectively provide particles and low-temperature gas. The turbulent air field mixing system comprises a tapered cylinder with a small upper part and a large lower part, which realizes turbulent flow of low-temperature gas; the upper part of the tapered cylinder is provided with the liquid atomization system to atomize the concentrated liquid into atomized droplets, which are fully mixed with the turbulent low-temperature gas into a gas-liquid two-phase mixed fluid. The upper part of the tapered cylinder is provided with the laminar air field mixing system to adjust the turbulent flow of the gas-liquid mixed fluid into laminar flow. The upper part of the laminar air field mixing system is provided with the suspended particle system, and the concentrated liquid atomized droplets collide with the suspended particles to be absorbed and rapidly evaporated.

2. A device for the treatment of a low temperature spray-dried suspension of particles in a three-phase concentrate according to claim 1, characterized in that The suspended particle system utilizes the balance between the gravity of the particles and the resistance formed by the relative motion of the gas-liquid mixed fluid and the particles to form a stable suspended particle layer.

3. A device for the treatment of a low temperature three-phase suspension of particles by spray drying according to claim 1 or 2, characterised in that The particle collection and discharge system is arranged in the tapered cylinder, and the particle collection system comprises a discharge hopper arranged with a large lower part and a small upper part, which hinders the turbulent air field by gradually reducing the diameter of the tapered cylinder and gradually increasing the diameter of the discharge hopper to realize turbulent flow of low-temperature gas; the taper angle of the tapered cylinder is 30-60°.

4. A device for the treatment of a low temperature three-phase spray-drying concentrate of suspended particles according to claim 1 or 2, characterized in that, The liquid atomization system comprises a concentrated liquid delivery pipe and an atomizing nozzle connected with each other.

5. A device for the treatment of a low temperature three-phase suspension of particles by spray drying according to claim 1 or 2, characterized in that The laminar air field mixing system comprises a flow regulating assembly, which adopts a blade type, a hole plate type or a combination of blade and hole plate type gas flow regulator.

6. A device for the treatment of a low temperature spray-drying concentrate of suspended particles according to claim 1 or 2, characterized in that, The gas-solid separation, condensed water recovery and tail gas deodorization system is located at the upper part of the device, and comprises a cyclone separator, a water collector, a condenser and a subsequent deodorization system connected in sequence.

7. A method of processing a concentrate using the apparatus for processing a concentrate of any one of claims 1-6, wherein the method comprises: The device comprises: The particle supply system is used to uniformly supply light particles from the top of the device; The low-temperature tail gas is uniformly supplied from the bottom of the device by the low-temperature gas supply system; The turbulent air field mixing system forms a turbulent air field when the low-temperature hot air diffuses upward, and rapidly and fully mixes with the concentrated liquid atomized droplets to form a gas-liquid two-phase mixed fluid; The gas-liquid two-phase mixed fluid continues to flow upward into the laminar air field mixing system to adjust the turbulent flow into laminar flow; The laminar flow mixed fluid uniformly and balancedly enters the suspended particle system to form a gas-liquid-solid three-phase mixed fluid, in which the concentrated liquid atomized droplets collide with the suspended particles to be absorbed and rapidly evaporated; the suspended particles enriched with salt and residual liquid increase in weight and lose stability to fall into the particle collection and discharge system for discharge.

8. The method of claim 7, wherein, The low-temperature tail gas includes low-temperature coal-fired tail gas and low-temperature industrial tail gas, and the temperature of the tail gas is 50-100℃; the concentrated liquid is landfill leachate membrane concentrated liquid or concentrated liquid generated in industrial enterprise sewage zero discharge engineering.

9. The method of claim 7 or 8, wherein, The suspended particles are calcium-carbon-based mesoporous particles with a mesoporous pore size of 18-20nm; the particle size of the suspended particles is 3-5mm.

10. The method of claim 8 or 9, wherein, The upwardly escaping gas-liquid-solid three-phase mixed fluid enters a gas-solid separation, condensed water recovery and tail gas deodorization system to realize gas-solid separation, solid particles fall into a discharge bin for discharge, escaping liquid drops are physically recovered and concentrated liquid is recovered by a water collector, water vapor is recycled after being recovered by a condenser, and tail gas is discharged after deodorization treatment.

Images