System and method for reactivating and circularly deacidifying waste incineration fly ash

Abstract

The invention relates to the technical field of fly ash treatment, in particular to a system and a method for reactivating and circularly deacidifying waste incineration fly ash. The system comprises: an efficient dry reactor; the high-efficiency dry-process reactor comprises an A-section tower and a B-section tower; the A-section tower and the B-section tower are connected through a bottom elbow, and a Venturi-like reducing opening is formed in an inlet of the elbow; a flue gas circulating device and a flue gas humidifying device are sequentially arranged on the inner wall of the tower body of the section A tower in the flue gas flowing direction; a fly ash inlet is formed in the side wall of the tower body of the B-section tower; a fly ash reactivation device; a fly ash outlet of the fly ash reactivation device is connected with a fly ash inlet of the B-section tower; the dust remover is connected with a flue gas outlet of the B-section tower; the dust remover is provided with a flue gas outlet and a fly ash outlet; the fly ash recycling and conveying device is connected with a fly ash outlet of the dust remover; and a fly ash outlet of the fly ash recycling and conveying device is connected with a fly ash inlet of the fly ash reactivation device. The system and the method provided by the invention have better deacidification efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of fly ash treatment, and in particular to a system and method for reactivating, cyclically removing acid from waste incineration fly ash. Background Art

[0002] In the treatment of waste incineration flue gas, dry deacidification often involves spraying the deacidifier directly into the flue with a nozzle. The deacidifier passes through the flue and the surface of the bag to form a deacidification effect. However, due to the short mixing time in the flue and the poor mixing effect, the deacidifier consumption is large.

[0003] Patent application document CN 215428213 U discloses a desulfurization agent recycling and uniform distribution system for dry desulfurization, including a desulfurization tower, a dust collector, a material conveying device, a rotary feeding device and a fluidized air uniform mixing device, the top of the desulfurization tower is connected to the inlet of the dust collector, the flue gas discharged from the upper part of the desulfurization tower is separated by gas and solid through the dust collector, the outlet of the dust collector is connected to the material conveying device, the desulfurization agent separated by the dust collector is conveyed by the material conveying device, the output end of the material conveying device is connected to the feed end of the fluidized air uniform mixing device through the rotary feeding device, a feeding port is provided on one side of the fluidized air uniform mixing device, and the discharge end of the fluidized air uniform mixing device is connected to the desulfurization tower. The system can improve the reaction efficiency of the desulfurization agent and make full use of the desulfurization agent.

[0004] In the above-mentioned prior art, humidification is only one-time humidification, and the humidification effect and water volume control are poor, which cannot meet various working conditions. When more water is added, more fly ash circulation is required, resulting in unnecessary waste. Fly ash activation only adopts humidification, and there is no good control method for the easy compaction of waste incineration fly ash. One-side feeding will cause uneven distribution of particles in the reaction tower, affecting the removal efficiency. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a system and method for reactivating and cyclically deacidifying fly ash from waste incineration, which has a better deacidification effect.

[0006] The present invention provides a system for reactivating and cyclically removing acid from fly ash from garbage incineration, comprising:

[0007] A high-efficiency dry reactor; the high-efficiency dry reactor comprises a section A tower and a section B tower; the section A tower and the section B tower are connected by a bottom elbow, and a venturi-like reduction port is arranged at the inlet of the elbow; a flue gas inlet is arranged at the top of the section A tower; a flue gas outlet is arranged at the top of the section B tower; a flue gas circulation device and a flue gas humidification device are arranged in sequence on the inner wall of the tower body of the section A tower along the flow direction of the flue gas; a fly ash inlet is arranged on the side wall of the tower body of the section B tower;

[0008] A fly ash reactivation device; the fly ash outlet of the fly ash reactivation device is connected to the fly ash inlet of the section B tower;

[0009] A dust collector connected to the flue gas outlet of the B-stage tower; the dust collector is provided with a flue gas outlet and a fly ash outlet;

[0010] A fly ash recycling and conveying device is connected to the fly ash outlet of the dust collector; the fly ash outlet of the fly ash recycling and conveying device is connected to the fly ash inlet of the fly ash reactivation device.

[0011] Preferably, a deacidification agent injection port is provided in the high-efficiency dry reactor for injecting the deacidification agent.

[0012] Preferably, the fly ash reactivation device comprises:

[0013] An intermediate weighing hopper; the intermediate weighing hopper is provided with a fly ash inlet; a fly ash external discharge unloader is provided in the intermediate weighing hopper; the fly ash external discharge port of the fly ash external discharge unloader is the fly ash external discharge port of the intermediate weighing hopper; a fly ash variable frequency unloader is provided at the bottom of the intermediate weighing hopper;

[0014] A fly ash humidifying device is connected to the fly ash outlet of the fly ash variable frequency discharger; the fly ash outlet of the fly ash humidifying device is connected to the fly ash inlet of the B-stage tower.

[0015] Preferably, a fluidizing device is provided at the lower part of the intermediate weighing bucket; the fluidizing device is a fluidizing plate;

[0016] The fly ash variable frequency discharger is a screw discharger.

[0017] Preferably, the fly ash reactivation device further comprises: a fly ash grinding activation device;

[0018] The fly ash inlet of the fly ash grinding activation device is connected to the fly ash outlet of the fly ash variable frequency discharger, and the fly ash outlet of the fly ash grinding activation device is connected to the fly ash inlet of the fly ash humidifying device.

[0019] Preferably, the fly ash humidification device comprises a primary fly ash humidification conveyor and a secondary fly ash humidification conveyor connected in sequence; the fly ash inlet of the primary fly ash humidification conveyor is connected to the fly ash outlet of the fly ash grinding activation device; the fly ash outlet of the secondary fly ash humidification conveyor is connected to the fly ash inlet of the high-efficiency dry deacidification tower.

[0020] The present invention also provides a method for reactivating and cyclically deacidifying fly ash from waste incineration, comprising the following steps:

[0021] S1) Flue gas enters the A-stage tower of the high-efficiency dry reactor, passes through the flue gas circulation device and enters the flue gas humidification device for pre-cooling;

[0022] S2) the pre-cooled flue gas passes through a venturi-like reduction port and enters the B-stage tower of the high-efficiency dry reactor, and the flue gas discharged from the top of the B-stage tower is dedusted by a dust collector; the flue gas after dedusting is purified flue gas;

[0023] S3) The fly ash after dust removal is transported to the fly ash reactivation device, and after grinding and activation, enters the B section tower from the fly ash inlet on the side wall of the tower body of the B section tower.

[0024] Preferably, in step S1), the flue gas contains SO 2 The content is 200~600mg / Nm 3 , HCl content is 400~1200mg / Nm 3 ;

[0025] The flue gas temperature at the flue gas inlet of the A section tower of the high-efficiency dry reactor is 145-220°C;

[0026] The flue gas temperature after the pre-cooling is 145-180°C.

[0027] Preferably, step S3) comprises:

[0028] a) After the fly ash after dust removal is weighed in the intermediate weighing bucket, a portion of the fly ash is sent to the fly ash grinding activation device through the fly ash variable frequency discharger for grinding, and the other portion of the fly ash is discharged through the fly ash external discharger;

[0029] b) The fly ash after grinding and crushing is transported to the fly ash humidification device for humidification and then enters the B-stage tower.

[0030] Preferably, in step b), the fly ash after grinding and crushing is transported to a fly ash humidification device for humidification, comprising:

[0031] The fly ash after grinding and crushing is transported to the fly ash primary humidification conveyor for primary humidification, and then transported to the fly ash secondary humidification conveyor for secondary humidification;

[0032] The humidity of fly ash after secondary humidification is not less than 2%.

[0033] The technical solution of the present invention has higher deacidification efficiency, higher utilization rate of slaked lime, lower slaked lime consumption and higher efficiency than the existing dry method; and the fly ash output will also be reduced accordingly. At the same time, the present invention does not have high requirements for the inlet flue gas temperature of the high-efficiency dry reactor, and can meet a wide range of requirements of 145 to 220°C. Compared with the existing semi-dry method, the inlet flue gas temperature can be reduced from 200°C to 145°C, effectively improving the thermal efficiency of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1A system diagram of waste incineration fly ash reactivation cycle deacidification provided in one embodiment of the present invention;

[0035] Figure 2 A structural diagram of a fly ash reactivation device provided for one embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with 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.

[0037] The present invention provides a system for reactivating and cyclically removing acid from fly ash from garbage incineration, comprising:

[0038] A high-efficiency dry reactor; the high-efficiency dry reactor comprises a section A tower and a section B tower; the section A tower and the section B tower are connected by a bottom elbow, and a venturi-like reduction port is arranged at the inlet of the elbow; a flue gas inlet is arranged at the top of the section A tower; a flue gas outlet is arranged at the top of the section B tower; a flue gas circulation device and a flue gas humidification device are arranged in sequence on the inner wall of the tower body of the section A tower along the flow direction of the flue gas; a fly ash inlet is arranged on the side wall of the tower body of the section B tower;

[0039] A fly ash reactivation device; the fly ash outlet of the fly ash reactivation device is connected to the fly ash inlet of the section B tower;

[0040] A dust collector connected to the flue gas outlet of the B-stage tower; the dust collector is provided with a flue gas outlet and a fly ash outlet;

[0041] A fly ash recycling and conveying device is connected to the fly ash outlet of the dust collector; the fly ash outlet of the fly ash recycling and conveying device is connected to the fly ash inlet of the fly ash reactivation device.

[0042] Figure 1 A system diagram of fly ash reactivation and deacidification for waste incineration provided in one embodiment of the present invention. 1 is a high-efficiency dry reactor, which includes a section A tower and a section B tower, 1-1 is the section A tower of the high-efficiency dry reactor, 1-2 is the section B tower of the high-efficiency dry reactor; 2 is a flue gas circulation device; 3 is a flue gas humidification device; 4 is a fly ash reactivation device; 5 is a dust collector; 6 is a fly ash recycling and conveying device.

[0043] In the present invention, the section A tower 1-1 and the section B tower 1-2 are connected by a bottom elbow, and a venturi-like reduction port is provided at the entrance of the elbow to prevent fly ash from accumulating at the bottom of the reactor. A flue gas inlet is provided at the top of the section A tower 1-1; a flue gas outlet is provided at the top of the section B tower 1-2. The inner lining of the section B tower 1-2 is a wear-resistant steel plate. Along the flow direction of the flue gas, a flue gas circulation device 2 and a flue gas humidification device 3 are sequentially provided on the inner wall of the tower body of the section A tower 1-1; a fly ash inlet is provided on the side wall of the tower body of the section B tower 1-2.

[0044] In the present invention, a deacidification agent injection port is provided in the high-efficiency dry reactor 1 for injecting the deacidification agent. The present invention has no particular limitation on the location of the deacidification agent injection port, and the deacidification agent injection port can be provided in the A-stage tower 1-1 or the B-stage tower 1-2. In some embodiments, the deacidification agent injection port is provided in the A-stage tower 1-1.

[0045] In certain embodiments of the present invention, the flue gas of the flue gas circulation device 2 is taken from at least one of the flue gas after the dust collector and the low-temperature sulfur-free flue gas. The functions of the flue gas circulation device 2 are as follows: 1. Used as a backup cooling device, the use of low-temperature sulfur-free flue gas or ambient air mixed with the original flue gas can be used to cool down the flue gas under the premise of increasing the relative humidity less. It is suitable for replacing the spray gun of the flue gas humidification system for pre-cooling when the relative humidity of the original flue gas is high or the HCl concentration is too high. 2. When the boiler load is low and the flue gas volume is much lower than the design volume, turn on the flue gas circulation device 2, and the clean flue gas from the dust collector returns to the inlet of the high-efficiency dry reactor, so that the reactor flow rate reaches the design requirements, and prevents dust deposition or unsmooth fly ash circulation caused by low flow rate.

[0046] Specifically, the flue gas circulation device 2 may be a flue gas circulation duct.

[0047] In some embodiments of the present invention, the flue gas humidification device 3 is a flue gas humidification spray gun, specifically a dual-fluid humidification spray gun. The function of the flue gas humidification device 3 is to pre-cool the flue gas temperature. The cooling range is related to the inlet and outlet acidic pollution and the inlet temperature. Theoretically, the flue gas temperature after cooling is 145-180°C. The specific temperature control is jointly controlled by the inlet and outlet acidic pollutants, the fly ash circulation volume and the inlet temperature, and a logical chain is performed.

[0048] The flue gas after pre-cooling by the flue gas humidification device 3 enters the venturi-like reduction port in the high-efficiency dry reactor, which is mainly used to prevent the circulating fly ash from depositing and causing the high-efficiency dry reactor to be blocked. The size range of the venturi-like reduction port is set according to the concentration of pollutants and the flue gas volume.

[0049] In the present invention, the fly ash outlet of the fly ash reactivation device 4 is connected to the fly ash inlet of the B-stage tower 1-2. A fly ash distribution plate is arranged at the fly ash inlet of the B-stage tower 1-2.

[0050] In certain embodiments of the present invention, the fly ash reactivation device 4 comprises:

[0051] An intermediate weighing hopper; the intermediate weighing hopper is provided with a fly ash inlet; a fly ash external discharge unloader is provided in the intermediate weighing hopper; the fly ash external discharge port of the fly ash external discharge unloader is the fly ash external discharge port of the intermediate weighing hopper; a fly ash variable frequency unloader is provided at the bottom of the intermediate weighing hopper;

[0052] A fly ash humidifying device is connected to the fly ash outlet of the fly ash variable frequency discharger; the fly ash outlet of the fly ash humidifying device is connected to the fly ash inlet of the B-stage tower.

[0053] Figure 2 The structure diagram of the fly ash reactivation device provided by one embodiment of the present invention, wherein 4-1 is an intermediate weighing hopper, 4-2 is a fly ash external discharger, 4-3 is a fly ash variable frequency discharger, 4-4 is a fly ash grinding activation device, 4-5 is a fly ash humidification device, 4-5-1 is a fly ash primary humidification conveyor, 4-5-2 is a fly ash secondary humidification conveyor, 4-6 is a fly ash distribution plate, and 1-2 is a B-stage tower of a high-efficiency dry reactor. Figure 2 Section B Tower 1-2 in the figure only shows a part of the tower.

[0054] The fly ash inlet of the intermediate weighing hopper 4-1 is the fly ash inlet of the fly ash reactivation device 4. The fly ash outlet of the fly ash recycling and conveying device 6 is connected to the fly ash inlet of the intermediate weighing hopper 4-1.

[0055] In some embodiments of the present invention, the fly ash discharge port of the fly ash discharger 4-2 is connected to the ash silo. The fly ash discharger is a screw discharger.

[0056] The fly ash transported by the fly ash recycling and conveying device 6 enters the intermediate weighing hopper 4-1. The intermediate weighing hopper has a weighing function and can distribute the fly ash in the hopper according to the required circulation ratio. One part is sent to the fly ash grinding activation device through the fly ash variable frequency unloading machine, and the other part is unloaded to the ash bin through the fly ash external discharge unloading machine.

[0057] In some embodiments of the present invention, a fluidizing device is provided at the lower part of the intermediate weighing hopper 4-1, and the fluidizing air temperature is not lower than 140°C to prevent the fly ash from agglomerating and agglomerating. The fluidizing device is a fluidizing plate.

[0058] In certain embodiments of the present invention, the fly ash variable frequency discharger 4 - 3 is a screw discharger.

[0059] The fly ash is sent to the fly ash grinding activation device through the fly ash variable frequency unloader. The delivery volume of the fly ash variable frequency unloader is the fly ash circulation volume. The fly ash circulation volume is controlled by the fly ash humidification device, inlet and outlet acidic pollutants, flue gas flow rate, and reactor pressure difference, and a logical chain is performed.

[0060] In some embodiments of the present invention, the fly ash reactivation device 4 further comprises: a fly ash grinding activation device 4-4. The fly ash inlet of the fly ash grinding activation device 4-4 is connected to the fly ash outlet of the fly ash variable frequency discharger 4-3, and the fly ash outlet of the fly ash grinding activation device 4-4 is connected to the fly ash inlet of the fly ash humidification device 4-5.

[0061] The fly ash in the intermediate weighing hopper 4-1 is transported to the fly ash grinding activation device 4-4 through the fly ash variable frequency discharger 4-3. The fly ash grinding activation device mainly adopts the principle of mechanical grinding and crushing, and grinds or crushes the circulating fly ash by rolling, vibrating or injecting steam into the fly ash. In addition to grinding the agglomerated fly ash with larger particles, this process can also remove the covering layer covering the surface of the unreacted slaked lime, thereby increasing the reaction specific surface area of ​​the slaked lime.

[0062] In certain embodiments of the present invention, the fly ash grinding and activation device 4 - 4 is a conventional fly ash crushing and grinding device, including but not limited to a ball mill and the like.

[0063] In certain embodiments of the present invention, the fly ash humidification device 4-5 comprises a fly ash primary humidification conveyor 4-5-1 and a fly ash secondary humidification conveyor 4-5-2 which are connected in sequence; the fly ash inlet of the fly ash primary humidification conveyor 4-5-1 is connected to the fly ash outlet of the fly ash grinding activation device; the fly ash outlet of the fly ash secondary humidification conveyor 4-5-2 is connected to the fly ash inlet of the high-efficiency dry deacidification tower.

[0064] The ground fly ash enters the fly ash primary humidification conveyor 4-5-1 for primary humidification. This equipment is mainly based on a twin-screw conveying system. Atomized water is sprayed at a fixed position during the conveying process to achieve the humidification activation function. The twin screw uses a variety of blade combinations or non-uniform blades to ensure the mixing of fly ash and water and prevent the problem of caking. The humidification nozzle adopts a multi-nozzle and small flow method. In addition to using water as the humidification medium, steam humidification can also be used if the flue gas temperature is too low, so that the expected humidification indicators can be achieved under the premise of ensuring the lowest flue gas temperature. The above design is used to ensure the uniformity of humidification and prevent caking.

[0065] In the fly ash humidification device, the humidification water volume is controlled by the inlet and outlet acid pollutants, the fly ash circulation volume, the flue gas flow rate and the inlet flue gas temperature, and is logically interlocked. If steam humidification is used, the inlet and outlet acid pollutants and the fly ash circulation volume are jointly controlled.

[0066] The circulating ash after the primary humidification of the fly ash enters the secondary humidification conveyor 4-5-2, which is similar in design to the primary humidification conveyor of the fly ash, but with a lower humidification capacity. In certain embodiments of the present invention, the primary humidification conveyor of the fly ash and the secondary humidification conveyor of the fly ash can be independently selected from a double-shaft humidifier or a double-screw conveyor.

[0067] The circulating ash humidified by the fly ash secondary humidification conveyor 4-5-2 is transported to the B-stage tower 1-2 through its own spiral.

[0068] In certain embodiments of the present invention, the dust collector 5 is a bag dust collector, and a conventional bag dust collector well known to those skilled in the art can be used. The smoke after dust removal enters a subsequent treatment system or is directly discharged.

[0069] In certain embodiments of the present invention, a branch is provided in the flue gas outlet pipe of the dust collector 5 , and the branch is connected to the circulating flue gas inlet of the flue gas circulation device 2 .

[0070] In certain embodiments of the present invention, the fly ash recycling and conveying device 6 is used to convey the fly ash collected by the bag filter to the fly ash reactivation device 4, and can be pneumatically or mechanically conveyed. The fly ash recycling and conveying device is a conventional screw conveying device, such as a screw conveyor.

[0071] The system for reactivating and cyclically deacidifying waste incineration fly ash provided by the present invention may be an automatic control system.

[0072] The present invention also provides a method for reactivating and cyclically deacidifying fly ash from waste incineration, comprising the following steps:

[0073] A) Flue gas enters the A-stage tower of the high-efficiency dry reactor, passes through the flue gas circulation device and enters the flue gas humidification device for pre-cooling;

[0074] B) passing the pre-cooled flue gas through a venturi-like reduction port and then entering the B-stage tower of the high-efficiency dry reactor, and the flue gas discharged from the top of the B-stage tower is dedusted by a dust collector; the flue gas after dedusting is purified flue gas;

[0075] C) transporting the dedusted fly ash to the fly ash reactivation device, grinding and activating it, and then entering the B-section tower from the fly ash inlet on the side wall of the B-section tower body.

[0076] In step A):

[0077] In certain embodiments of the present invention, the flue gas (conventional domestic waste incineration flue gas) contains SO 2 The content is 200~600mg / Nm 3, HCl content is 400~1200mg / Nm 3 .

[0078] In certain embodiments of the present invention, the flue gas temperature at the flue gas inlet of the A-stage tower of the high-efficiency dry reactor is 145-220°C, such as 180°C.

[0079] In some embodiments of the present invention, the flue gas temperature after pre-cooling is 145-180° C., such as 160° C. The specific temperature control is jointly controlled by the inlet and outlet acid pollutants, the fly ash circulation amount and the inlet temperature, and is logically linked.

[0080] In certain embodiments of the present invention, after the pre-cooling, the flue gas is deacidified. Specifically, the deacidification is performed by spraying a deacidifying agent into the flue gas. The deacidifying agent may be slaked lime. The excess coefficient of slaked lime is not higher than 1.6.

[0081] In certain embodiments of the present invention, step C) comprises:

[0082] a) After the fly ash after dust removal is weighed in the intermediate weighing bucket, a portion of the fly ash is sent to the fly ash grinding activation device through the fly ash variable frequency discharger for grinding, and the other portion of the fly ash is discharged through the fly ash external discharger;

[0083] b) The fly ash after grinding and crushing is transported to the fly ash humidification device for humidification and then enters the B-stage tower.

[0084] In step a):

[0085] In certain embodiments of the present invention, the fly ash after dust removal is transported to an intermediate weighing hopper via a fly ash recycling and conveying device.

[0086] In some embodiments of the present invention, a portion of the fly ash enters the fly ash variable frequency discharger through the fluidizing device. The fluidizing air temperature is not less than 140°C, such as 150°C.

[0087] In certain embodiments of the present invention, the circulation rate of the fly ash is not less than 20, such as 25.

[0088] The fly ash after discharge is transported to the ash storage.

[0089] In step b):

[0090] In certain embodiments of the present invention, the fly ash after grinding and crushing is transported to a fly ash humidification device for humidification, comprising:

[0091] The fly ash after grinding and crushing is transported to the fly ash primary humidification conveyor for primary humidification, and then transported to the fly ash secondary humidification conveyor for secondary humidification.

[0092] The humidity of the fly ash after secondary humidification is not less than 2%, for example, 3% to 5%.

[0093] In certain embodiments of the present invention, the flue gas after dust removal is purified flue gas, in which SO 2 The content is 5~30mg / Nm 3 , the content of HCl is 2~6mg / Nm 3 .

[0094] The present invention is to further increase the mixing effect of the deacidifying agent (such as slaked lime) and flue gas and the activity of the circulating fly ash, thereby improving the utilization rate of the deacidifying agent and increasing the deacidifying effect.

[0095] Beneficial effects:

[0096] 1. The technical solution of the present invention has a higher deacidification efficiency. Specifically, SO 2 Removal efficiency>95%, HCl removal efficiency>99%; higher utilization rate of slaked lime, lower consumption of slaked lime than the existing dry method, higher efficiency. And the fly ash output will also be reduced accordingly.

[0097] 2. The present invention does not have high requirements on the inlet flue gas temperature of the high-efficiency dry reactor, and can meet a wide range of requirements of 145 to 220°C. Compared with the existing semi-dry method, the inlet flue gas temperature can be reduced from 200°C to 145°C, effectively improving the thermal efficiency of the boiler.

[0098] 3. The overall equipment is more compact, and the investment and construction period are reduced accordingly.

[0099] In order to further illustrate the present invention, a system and method for reactivating and cyclically removing acid from waste incineration fly ash provided by the present invention are described in detail below in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0100] Example

[0101] Use Figure 1 The waste incineration fly ash reactivation cycle deacidification system shown in the figure performs waste incineration fly ash reactivation cycle deacidification:

[0102] The system comprises:

[0103] A high-efficiency dry reactor 1; the high-efficiency dry reactor comprises a section A tower 1-1 and a section B tower 1-2; the section A tower and the section B tower are connected by a bottom elbow, and a venturi-like reduction port is provided at the inlet of the elbow; a flue gas inlet is provided at the top of the section A tower 1-1; a flue gas outlet is provided at the top of the section B tower 1-2; a flue gas circulation device 2 and a flue gas humidification device 3 are provided in sequence on the inner wall of the tower body of the section A tower 1-1 along the flow direction of the flue gas; a fly ash inlet is provided on the side wall of the tower body of the section B tower 1-2;

[0104] The high-efficiency dry reactor 1 is provided with a deacidification agent injection port for injecting the deacidification agent; the deacidification agent injection port is arranged in the A-stage tower 1-1; the flue gas circulation device 2 is a flue gas circulation pipeline; the flue gas humidification device 3 is a dual-fluid humidification spray gun;

[0105] A fly ash reactivation device 4; the fly ash outlet of the fly ash reactivation device 4 is connected to the fly ash inlet of the B-section tower 1-2; a fly ash distribution plate is provided at the fly ash inlet of the B-section tower 1-2;

[0106] The fly ash reactivation device 4 adopts Figure 2 The fly ash reactivation device shown comprises:

[0107] The intermediate weighing hopper 4-1; the fly ash inlet of the intermediate weighing hopper 4-1 is the fly ash inlet of the fly ash reactivation device 4; the fly ash outlet of the fly ash recycling and conveying device 6 is connected to the fly ash inlet of the intermediate weighing hopper 4-1;

[0108] A fly ash discharger 4-2 is arranged in the intermediate weighing hopper 4-1; the fly ash discharger 4-2 is a screw discharger; the fly ash discharge port of the fly ash discharger 4-2 is the fly ash discharge port of the intermediate weighing hopper; a fly ash variable frequency discharger 4-3 is arranged at the bottom of the intermediate weighing hopper; the fly ash variable frequency discharger 4-3 is a screw discharger;

[0109] A fly ash grinding activation device 4-4; the fly ash grinding activation device 4-4 is a ball mill; the fly ash inlet of the fly ash grinding activation device 4-4 is connected to the fly ash outlet of the fly ash variable frequency discharger 4-3, and the fly ash outlet of the fly ash grinding activation device 4-4 is connected to the fly ash inlet of the fly ash humidification device 4-5;

[0110] The fly ash humidification device 4-5 comprises a fly ash primary humidification conveyor 4-5-1 and a fly ash secondary humidification conveyor 4-5-2 which are connected in sequence; the fly ash inlet of the fly ash primary humidification conveyor 4-5-1 is connected to the fly ash outlet of the fly ash grinding activation device; the fly ash outlet of the fly ash secondary humidification conveyor 4-5-2 is connected to the fly ash inlet of the high-efficiency dry deacidification tower; the fly ash primary humidification conveyor 4-5-1 and the fly ash secondary humidification conveyor 4-5-2 are both selected from biaxial humidifiers;

[0111] The circulating ash humidified by the fly ash secondary humidification conveyor 4-5-2 is conveyed to the B-stage tower 1-2 by its own spiral;

[0112] A dust collector 5 connected to the flue gas outlet of the B-stage tower; the dust collector 5 is a bag dust collector; the dust collector 5 is provided with a flue gas outlet and a fly ash outlet; a branch is provided in the flue gas outlet pipe of the dust collector 5, and the branch is connected to the circulating flue gas inlet of the flue gas circulation device 2;

[0113] A fly ash recycling and conveying device 6 is connected to the fly ash outlet of the dust collector; the fly ash outlet of the fly ash recycling and conveying device 6 is connected to the fly ash inlet of the fly ash reactivation device 4; the fly ash recycling and conveying device 6 is a screw conveyor.

[0114] The method for reactivating and recycling the deacidification of waste incineration fly ash comprises the following steps:

[0115] 1. In flue gas (conventional domestic waste incineration flue gas), SO 2 The content is 200~600mg / Nm 3 , HCl content is 400~1200mg / Nm 3 ;

[0116] The flue gas enters the A-stage tower of the high-efficiency dry reactor 1, passes through the flue gas circulation device 2 and enters the flue gas humidification device 3 for pre-cooling; the flue gas temperature after pre-cooling is 160°C; the flue gas temperature at the flue gas inlet of the A-stage tower of the high-efficiency dry reactor 1 is 180°C;

[0117] After the pre-cooling, deacidification is performed by spraying a deacidifying agent (the deacidifying agent is slaked lime, and the excess coefficient of slaked lime is not higher than 1.6) into the flue gas;

[0118] 2. The pre-cooled flue gas passes through a venturi-like reduction port and enters the B-stage tower of the high-efficiency dry reactor 1. The flue gas discharged from the top of the B-stage tower is dedusted by a dust collector 5; the flue gas after dedusting is purified flue gas;

[0119] 3. The fly ash after dust removal is transported to the intermediate weighing hopper 4-1 through the fly ash recycling and conveying device 6; after being weighed by the intermediate weighing hopper 4-1, a part of the fly ash passes through the fluidizing device (the fluidizing device is a fluidizing plate, and the fluidizing air temperature is 150°C) and enters the fly ash variable frequency discharger 4-3, and is sent to the fly ash grinding activation device 4-4 through the fly ash variable frequency discharger 4-3 for grinding, and the other part of the fly ash is discharged through the fly ash external discharger 4-2; the circulation ratio of the fly ash is 25; the fly ash after external discharge is transported to the ash storage;

[0120] The fly ash after grinding and crushing is transported to the fly ash primary humidification conveyor 4-5-1 for primary humidification, and then transported to the fly ash secondary humidification conveyor 4-5-2 for secondary humidification before entering the tower of section B. The humidity of the fly ash after secondary humidification is 3% to 5%.

[0121] After testing, the purified flue gas contains SO 2 The content is 5~20mg / Nm 3 , the content of HCl is <2~6mg / Nm 3 . SO 2 Removal efficiency>97%, HCl removal efficiency>99%.

[0122] The description of the above embodiments is only used to help understand the method of the present invention and its core idea. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A system for reactivating and cyclically removing acid from fly ash from waste incineration, comprising: A high-efficiency dry reactor; the high-efficiency dry reactor comprises a section A tower and a section B tower; the section A tower and the section B tower are connected by a bottom elbow, and a venturi-like reduction port is arranged at the inlet of the elbow; a flue gas inlet is arranged at the top of the section A tower; a flue gas outlet is arranged at the top of the section B tower; a flue gas circulation device and a flue gas humidification device are arranged in sequence on the inner wall of the tower body of the section A tower along the flow direction of the flue gas; a fly ash inlet is arranged on the side wall of the tower body of the section B tower; A fly ash reactivation device; the fly ash outlet of the fly ash reactivation device is connected to the fly ash inlet of the section B tower; A dust collector connected to the flue gas outlet of the B-stage tower; the dust collector is provided with a flue gas outlet and a fly ash outlet; A fly ash recycling and conveying device is connected to the fly ash outlet of the dust collector; the fly ash outlet of the fly ash recycling and conveying device is connected to the fly ash inlet of the fly ash reactivation device.

2. The system according to claim 1, characterized in that The high-efficiency dry reactor is provided with a deacidification agent injection port for injecting the deacidification agent.

3. The system according to claim 1, characterized in that The fly ash reactivation device comprises: An intermediate weighing hopper; the intermediate weighing hopper is provided with a fly ash inlet; a fly ash external discharge unloader is provided in the intermediate weighing hopper; the fly ash external discharge port of the fly ash external discharge unloader is the fly ash external discharge port of the intermediate weighing hopper; a fly ash variable frequency unloader is provided at the bottom of the intermediate weighing hopper; A fly ash humidifying device is connected to the fly ash outlet of the fly ash variable frequency discharger; the fly ash outlet of the fly ash humidifying device is connected to the fly ash inlet of the B-stage tower.

4. The system according to claim 3, characterized in that A fluidizing device is provided at the lower part of the intermediate weighing bucket; the fluidizing device is a fluidizing plate; The fly ash variable frequency discharger is a screw discharger.

5. The system according to claim 3, characterized in that The fly ash reactivation device further comprises: a fly ash grinding activation device; The fly ash inlet of the fly ash grinding activation device is connected to the fly ash outlet of the fly ash variable frequency discharger, and the fly ash outlet of the fly ash grinding activation device is connected to the fly ash inlet of the fly ash humidifying device.

6. The system according to claim 5, characterized in that The fly ash humidification device comprises a primary fly ash humidification conveyor and a secondary fly ash humidification conveyor which are connected in sequence; the fly ash inlet of the primary fly ash humidification conveyor is connected to the fly ash outlet of the fly ash grinding activation device; the fly ash outlet of the secondary fly ash humidification conveyor is connected to the fly ash inlet of the high-efficiency dry deacidification tower.

7. A method for reactivating and cyclically deacidifying fly ash from waste incineration, comprising the following steps: S1) Flue gas enters the A-stage tower of the high-efficiency dry reactor, passes through the flue gas circulation device and enters the flue gas humidification device for pre-cooling; S2) the pre-cooled flue gas passes through a venturi-like reduction port and enters a section B tower of a high-efficiency dry reactor, and the flue gas discharged from the top of the section B tower is dedusted by a dust collector; The flue gas after dust removal is purified flue gas; S3) The fly ash after dust removal is transported to the fly ash reactivation device, and after grinding and activation, enters the B section tower from the fly ash inlet on the side wall of the tower body of the B section tower.

8. The method according to claim 7, characterized in that In step S1), the content of SO2 in the flue gas is 200-600 mg / Nm 3 , HCl content is 400~1200mg / Nm 3 ; The flue gas temperature at the flue gas inlet of the A section tower of the high-efficiency dry reactor is 145-220°C; The flue gas temperature after the pre-cooling is 145-180°C.

9. The method according to claim 7, characterized in that: Step S3) comprises: a) After the fly ash after dust removal is weighed in the intermediate weighing bucket, a portion of the fly ash is sent to the fly ash grinding activation device through the fly ash variable frequency discharger for grinding, and the other portion of the fly ash is discharged through the fly ash external discharger; b) The fly ash after grinding and crushing is transported to the fly ash humidification device for humidification and then enters the B-stage tower.

10. The method according to claim 9, characterized in that In step b), the fly ash after grinding and crushing is transported to a fly ash humidification device for humidification, comprising: The fly ash after grinding and crushing is transported to the fly ash primary humidification conveyor for primary humidification, and then transported to the fly ash secondary humidification conveyor for secondary humidification; The humidity of fly ash after secondary humidification is not less than 2%.

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