A system and method for reactivating and recycling acid removal from waste incineration fly ash

Abstract

The present application relates to fly ash treatment technical field, especially to a kind of garbage incineration fly ash reactivation system and method for cyclic deacidification.The system includes: efficient dry method reactor;Efficient dry method reactor includes A section tower and B section tower;The A section tower is connected with B section tower using bottom elbow, and venturi-like reduced port is set at elbow entrance;Along the flow direction of flue gas, flue gas circulating device and flue gas humidifying device are sequentially arranged in the inner wall of A section tower;Flue gas inlet is arranged in the side wall of B section tower;Fly ash reactivation device;The fly ash outlet of fly ash reactivation device is connected with the fly ash inlet of B section tower;Dust collector connected with the flue gas outlet of B section tower;The dust collector is provided with flue gas outlet and fly ash outlet;Fly ash recirculation conveying device connected with the fly ash outlet of the dust collector;The fly ash outlet of fly ash recirculation conveying device is connected with the fly ash inlet of fly ash reactivation device.The system and method of the present application have relatively optimal deacidification efficiency.

Description

Technical Field

[0001] This invention relates to the field of fly ash treatment technology, and in particular to a system and method for reactivating and recycling fly ash from waste incineration for acid removal. Background Technology

[0002] In waste incineration flue gas treatment, dry deacidification often involves directly spraying the deacidifying agent into the flue through a nozzle. The deacidifying agent passes through the flue and the surface of the filter bags to achieve a deacidification effect. However, due to the short mixing time in the flue and the poor mixing effect, the consumption of deacidifying agent is relatively large.

[0003] Patent application CN 215428213 U discloses a desulfurizing agent recycling and uniform distribution system for dry desulfurization, including a desulfurization tower, a dust collector, a material conveying device, a rotary feeder, and a fluidizing 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 undergoes gas-solid separation by the dust collector. The outlet of the dust collector is connected to the material conveying device, and the desulfurizing 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 inlet end of the fluidizing air uniform mixing device through the rotary feeder. A feed inlet is provided on one side of the fluidizing air uniform mixing device, and the outlet end of the fluidizing air uniform mixing device is connected to the desulfurization tower. This system can improve the reaction efficiency of the desulfurizing agent and make full use of the desulfurizing agent.

[0004] In the aforementioned existing technologies, humidification is only a one-time process, resulting in poor humidification effect and limited water volume control. This makes it unsuitable for various operating conditions, and requires more fly ash circulation when more water is added, leading to unnecessary waste. Fly ash activation only uses humidification, offering no effective means to control the caking of fly ash from waste incineration. Unilateral feeding leads to uneven particle distribution in the reaction tower, affecting 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 recycling fly ash from waste incineration to remove acid, which has a better acid removal effect.

[0006] This invention provides a system for reactivating and recycling acid removal from waste incineration fly ash, comprising:

[0007] A high-efficiency dry process reactor; the high-efficiency dry process reactor includes an A-section tower and a B-section tower; the A-section tower and the B-section tower are connected by a bottom elbow, and a Venturi-like constriction inlet is provided at the inlet of the elbow; a flue gas inlet is provided at the top of the A-section tower; a flue gas outlet is provided at the top of the B-section tower; along the flow direction of the flue gas, a flue gas circulation device and a flue gas humidification device are sequentially arranged on the inner wall of the A-section tower; a fly ash inlet is provided on the side wall of the B-section 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 B-section tower;

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

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

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

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

[0013] An intermediate weighing hopper is provided with a fly ash inlet; a fly ash discharge unloader is provided inside the intermediate weighing hopper; the fly ash discharge outlet of the fly ash discharge unloader is the fly ash discharge outlet 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 humidification device is connected to the fly ash outlet of the fly ash variable frequency unloader; the fly ash outlet of the fly ash humidification device is connected to the fly ash inlet of the B-section tower.

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

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

[0017] Preferably, the fly ash reactivation device further includes: 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 unloader, and the fly ash outlet of the fly ash grinding activation device is connected to the fly ash inlet of the fly ash humidification device.

[0019] Preferably, the fly ash humidification device includes 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 and activation device; and 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] This invention also provides a method for reactivating and recycling fly ash from waste incineration for acid removal, comprising the following steps:

[0021] S1) The flue gas enters the A-section 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 is passed through a Venturi-like constrictor and then enters the B-section tower of the high-efficiency dry reactor. The flue gas discharged from the top of the B-section tower is then subjected to dust removal by a dust collector. The flue gas after dust removal 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, it enters the B-section tower from the fly ash inlet on the side wall of the B-section tower.

[0024] Preferably, in step S1), the SO2 content in the flue gas is 200–600 mg / Nm³. 3 The HCl content is 400–1200 mg / Nm³. 3 ;

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

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

[0027] Preferably, step S3) includes:

[0028] a) After the dust removal, the fly ash is weighed in the intermediate weighing hopper. Part of the fly ash is sent to the fly ash grinding and activation device for grinding through the fly ash frequency conversion unloading machine, and the other part of the fly ash is discharged through the fly ash discharge unloading machine.

[0029] b) After being ground and crushed, the fly ash is conveyed to the fly ash humidification device for humidification and then enters the B-section tower.

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

[0031] After being ground and crushed, the fly ash is conveyed to the primary fly ash humidification conveyor for primary humidification, and then conveyed to the secondary fly ash humidification conveyor for secondary humidification.

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

[0033] The technical solution of this invention has higher acid removal efficiency and higher lime utilization rate, with lower lime consumption and higher efficiency than existing dry methods; and the fly ash production will also be reduced accordingly. At the same time, this 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 145-220℃. Compared with the existing semi-dry method, the inlet flue gas temperature can be reduced from 200℃ to 145℃, effectively improving the boiler thermal efficiency. Attached Figure Description

[0034] Figure 1A system diagram of a waste incineration fly ash reactivation and recycling deacidification system provided as an embodiment of the present invention;

[0035] Figure 2 This is a structural diagram of a fly ash reactivation device provided in an embodiment of the present invention. Detailed Implementation

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] This invention provides a system for reactivating and recycling acid removal from waste incineration fly ash, comprising:

[0038] A high-efficiency dry process reactor; the high-efficiency dry process reactor includes an A-section tower and a B-section tower; the A-section tower and the B-section tower are connected by a bottom elbow, and a Venturi-like constriction inlet is provided at the inlet of the elbow; a flue gas inlet is provided at the top of the A-section tower; a flue gas outlet is provided at the top of the B-section tower; along the flow direction of the flue gas, a flue gas circulation device and a flue gas humidification device are sequentially arranged on the inner wall of the A-section tower; a fly ash inlet is provided on the side wall of the B-section 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 B-section tower;

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

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

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

[0043] In this invention, the A-section tower 1-1 and the B-section tower 1-2 are connected by a bottom elbow, with a Venturi-like constriction at the elbow inlet to prevent fly ash from accumulating at the bottom of the reactor. A flue gas inlet is located at the top of the A-section tower 1-1; a flue gas outlet is located at the top of the B-section tower 1-2. The inner lining of the B-section tower 1-2 is made of 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 installed on the inner wall of the A-section tower 1-1; a fly ash inlet is located on the side wall of the B-section tower 1-2.

[0044] In this invention, the high-efficiency dry reactor 1 is equipped with a deacidifying agent injection port for injecting deacidifying agent. This invention does not impose any special restrictions on the location of the deacidifying agent injection port; it can be located in section A tower 1-1 or section B tower 1-2. In some embodiments, the deacidifying agent injection port is located in section A tower 1-1.

[0045] In some embodiments of the present invention, the flue gas of the flue gas recirculation device 2 is taken from at least one of the flue gas after the dust collector and low-temperature sulfur-free flue gas. The functions of the flue gas recirculation device 2 are: ① As a backup cooling system, using low-temperature sulfur-free flue gas or ambient air mixed with the original flue gas allows for cooling with minimal increase in relative humidity. This is suitable for pre-cooling when the relative humidity of the original flue gas is high or the HCl concentration is too high, replacing the spray guns of the flue gas humidification system. ② When the boiler load is low and the flue gas volume is significantly lower than the design volume, the flue gas recirculation device 2 is activated, allowing the clean flue gas from the dust collector to return to the inlet of the high-efficiency dry reactor, ensuring the reactor flow rate meets design requirements and preventing dust deposition or poor fly ash circulation caused by low flow rates.

[0046] Specifically, the flue gas recirculation device 2 can be a flue gas recirculation 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 pollutants and the inlet temperature. Theoretically, the cooled flue gas temperature is 145-180°C. The specific temperature control is jointly controlled by the inlet and outlet acidic pollutants, the fly ash circulation rate, and the inlet temperature, and is logically interlocked.

[0048] The flue gas, after being pre-cooled by the flue gas humidification device 3, enters the Venturi-like constriction in the high-efficiency dry reactor. This function is mainly to prevent the deposition of circulating fly ash, which could lead to blockage of the high-efficiency dry reactor. The size range of the Venturi-like constriction is set according to the concentration of pollutants and the flue gas volume.

[0049] In this invention, 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.

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

[0051] An intermediate weighing hopper is provided with a fly ash inlet; a fly ash discharge unloader is provided inside the intermediate weighing hopper; the fly ash discharge outlet of the fly ash discharge unloader is the fly ash discharge outlet 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 humidification device is connected to the fly ash outlet of the fly ash variable frequency unloader; the fly ash outlet of the fly ash humidification device is connected to the fly ash inlet of the B-section tower.

[0053] Figure 2 This is a structural diagram of a fly ash reactivation device provided in an embodiment of the present invention. In the diagram, 4-1 is an intermediate weighing hopper, 4-2 is a fly ash discharge unloader, 4-3 is a fly ash variable frequency unloader, 4-4 is a fly ash grinding and activation device, 4-5 is a fly ash humidification device, 4-5-1 is a primary fly ash humidification conveyor, 4-5-2 is a secondary fly ash humidification conveyor, 4-6 is a fly ash distribution plate, and 1-2 is the B-section tower of the high-efficiency dry reactor. Figure 2 Section B of the towers 1-2 only shows a part of the tower body.

[0054] The fly ash inlet of the intermediate weighing hopper 4-1 is also the fly ash inlet of the fly ash reactivation device 4. The fly ash outlet of the fly ash recirculation 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 discharge unloader 4-2 is connected to the ash silo. The fly ash discharge unloader is a screw unloader.

[0056] The fly ash conveyed by the fly ash recycling conveyor 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. Part of it is sent to the fly ash grinding and activation device through the fly ash frequency conversion unloader, and the other part is unloaded to the ash silo through the fly ash external discharge unloader.

[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 fly ash from agglomerating and clumping. The fluidizing device is a fluidizing plate.

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

[0059] Fly ash is fed to the fly ash grinding and activation device through the fly ash variable frequency unloader. The conveying capacity of the fly ash variable frequency unloader is the fly ash circulation capacity. The fly ash circulation capacity is jointly controlled by the fly ash humidification device, inlet and outlet acidic pollutants, flue gas flow rate, and reactor pressure difference, and is logically interlocked.

[0060] In some embodiments of the present invention, the fly ash reactivation device 4 further includes 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 unloader 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 conveyed to the fly ash grinding and activation device 4-4 via the fly ash variable frequency unloading machine 4-3. The fly ash grinding and activation device mainly adopts the principle of mechanical grinding and crushing. It grinds or crushes the circulating fly ash by means of tumbling, vibration or steam injection to impact the fly ash. In addition to grinding the larger agglomerated fly ash particles, this process can also remove the covering layer on the surface of unreacted hydrated lime, thereby increasing the reaction specific surface area of ​​the hydrated lime.

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

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

[0064] After grinding, the fly ash enters the primary humidification conveyor 4-5-1 for primary humidification. This equipment is mainly based on a twin-screw conveyor system, in which atomized water is sprayed at fixed positions during the conveying process to achieve the humidification activation function. The twin screws employ various blade combinations or non-uniform blade configurations to ensure mixing of fly ash and water and prevent caking. The humidification nozzles use a multi-nozzle, low-flow-rate method. In addition to water, steam can also be used as the humidification medium if the flue gas temperature is too low, thus achieving the desired humidification target while maintaining the lowest possible flue gas temperature. These design features ensure uniform humidification and prevent agglomeration.

[0065] In the fly ash humidification device, the humidification water volume is jointly controlled by the inlet and outlet acidic 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, it is jointly controlled by the inlet and outlet acidic pollutants and the fly ash circulation volume.

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

[0067] After being humidified by the fly ash secondary humidification conveyor 4-5-2, the circulating ash is conveyed to section B tower 1-2 by its own screw conveyor.

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

[0069] In some 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 some embodiments of the present invention, the fly ash recirculation 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 pneumatic or mechanical conveying. The fly ash recirculation conveying device is a conventional screw conveyor, such as a screw conveyor.

[0071] The waste incineration fly ash reactivation and recycling deacidification system provided by this invention can be an automatic control system.

[0072] This invention also provides a method for reactivating and recycling fly ash from waste incineration for acid removal, comprising the following steps:

[0073] A) The flue gas enters the A-section 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) The pre-cooled flue gas is passed through a Venturi-like constrictor and then enters the B-section tower of the high-efficiency dry reactor. The flue gas discharged from the top of the B-section tower is then subjected to dust removal by a dust collector. The flue gas after dust removal is purified flue gas.

[0075] C) The fly ash after dust removal is transported to the fly ash reactivation device, and after grinding and activation, it enters the B-section tower from the fly ash inlet on the side wall of the B-section tower.

[0076] In step A):

[0077] In some embodiments of the present invention, the SO2 content in the flue gas (conventional municipal solid waste incineration flue gas) is 200–600 mg / Nm³. 3The HCl content is 400–1200 mg / Nm³. 3 .

[0078] In some embodiments of the present invention, the flue gas temperature at the inlet of the A-section tower of the high-efficiency dry reactor is 145-220°C, for example, 180°C.

[0079] In some embodiments of the present invention, the temperature of the pre-cooled flue gas is 145–180°C, for example, 160°C. Specific temperature control is achieved through a logical interlocking mechanism, jointly controlled by the inlet and outlet acidic pollutants, the fly ash circulation rate, and the inlet temperature.

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

[0081] In some embodiments of the present invention, step C) includes:

[0082] a) After the dust removal, the fly ash is weighed in the intermediate weighing hopper. Part of the fly ash is sent to the fly ash grinding and activation device for grinding through the fly ash frequency conversion unloading machine, and the other part of the fly ash is discharged through the fly ash discharge unloading machine.

[0083] b) After being ground and crushed, the fly ash is conveyed to the fly ash humidification device for humidification and then enters the B-section tower.

[0084] In step a):

[0085] In some embodiments of the present invention, the fly ash after dust removal is conveyed to an intermediate weighing hopper via a fly ash recirculation conveying device.

[0086] In some embodiments of the present invention, a portion of the fly ash enters the fly ash variable frequency unloader via a fluidization device. The fluidization air temperature is not lower than 140°C, for example, 150°C.

[0087] In some embodiments of the present invention, the fly ash recycling rate is not less than 20, for example 25.

[0088] After being discharged, the fly ash is transported to the ash silo.

[0089] In step b):

[0090] In some embodiments of the present invention, the fly ash after grinding and crushing is conveyed to a fly ash humidification device for humidification, including:

[0091] After being ground and crushed, the fly ash is conveyed to the primary fly ash humidification conveyor for primary humidification, and then conveyed to the secondary fly ash humidification conveyor for secondary humidification.

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

[0093] In some embodiments of the present invention, the flue gas after dust removal is purified flue gas, and the SO2 content in the purified flue gas is 5-30 mg / Nm³. 3 The HCl content is 2–6 mg / Nm³. 3 .

[0094] This invention aims to further enhance the mixing effect of deacidifying agents (such as slaked lime) and flue gas, as well as the activity of circulating fly ash, thereby improving the utilization rate of deacidifying agents and increasing the deacidification effect.

[0095] Beneficial effects:

[0096] 1. The technical solution of this invention has higher deacidification efficiency, specifically, SO2 removal efficiency > 95% and HCl removal efficiency > 99%; the utilization rate of hydrated lime is higher, with lower hydrated lime consumption and higher efficiency than existing dry methods. Furthermore, fly ash production will also be reduced accordingly.

[0097] 2. 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 145-220℃. Compared with the existing semi-dry process, the inlet flue gas temperature can be reduced from 200℃ to 145℃, which effectively improves the boiler thermal efficiency.

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

[0099] To further illustrate the present invention, the following detailed description of a system and method for reactivating and recycling deacidification of waste incineration fly ash provided by the present invention is provided in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0100] Example

[0101] Adopting such Figure 1 The system shown is for the reactivation and recycling of waste incineration fly ash for acid removal.

[0102] The system includes:

[0103] A high-efficiency dry reactor 1; the high-efficiency dry reactor includes 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 constriction inlet 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; along the flow direction of the flue gas, a flue gas circulation device 2 and a flue gas humidification device 3 are sequentially arranged on the inner wall of the section A tower 1-1; a fly ash inlet is provided on the side wall of the section B tower 1-2;

[0104] The high-efficiency dry reactor 1 is equipped with a deacidifying agent injection port for injecting deacidifying agent; the deacidifying agent injection port is located in section A 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] 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, as follows: Figure 2 The fly ash reactivation device shown includes:

[0107] 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 recirculation conveying device 6 is connected to the fly ash inlet of the intermediate weighing hopper 4-1.

[0108] A fly ash discharge unloader 4-2 is installed inside the intermediate weighing hopper 4-1; the fly ash discharge unloader 4-2 is a screw unloader; the fly ash discharge port of the fly ash discharge unloader 4-2 is the fly ash discharge port of the intermediate weighing hopper; a fly ash variable frequency unloader 4-3 is installed at the bottom of the intermediate weighing hopper; the fly ash variable frequency unloader 4-3 is a screw unloader.

[0109] 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 unloader 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 includes a primary fly ash humidification conveyor 4-5-1 and a secondary fly ash humidification conveyor 4-5-2 connected in sequence; the fly ash inlet of the primary fly ash humidification conveyor 4-5-1 is connected to the fly ash outlet of the fly ash grinding and activation device; the fly ash outlet of the secondary fly ash humidification conveyor 4-5-2 is connected to the fly ash inlet of the high-efficiency dry deacidification tower; both the primary fly ash humidification conveyor 4-5-1 and the secondary fly ash humidification conveyor 4-5-2 are selected from twin-shaft humidifiers;

[0111] The circulating ash, after being humidified by the secondary humidification conveyor 4-5-2, is conveyed to section B tower 1-2 by its own screw conveyor;

[0112] A dust collector 5 is connected to the flue gas outlet of the B-section tower; the dust collector 5 is a bag filter; 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 recirculation conveying device 6 is connected to the fly ash outlet of the dust collector; the fly ash outlet of the fly ash recirculation conveying device 6 is connected to the fly ash inlet of the fly ash reactivation device 4; the fly ash recirculation conveying device 6 is a screw conveyor.

[0114] The method for reactivating and recycling fly ash from waste incineration for acid removal includes the following steps:

[0115] 1. The SO2 content in the flue gas (conventional municipal solid waste incineration flue gas) is 200-600 mg / Nm³. 3 The HCl content is 400–1200 mg / Nm³. 3 ;

[0116] The flue gas enters the A-section 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 temperature of the flue gas after pre-cooling is 160℃; the flue gas temperature at the flue gas inlet of the A-section tower of the high-efficiency dry reactor 1 is 180℃.

[0117] After the pre-cooling, deacidification is carried out by injecting 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 is passed through a Venturi-like constrictor and then enters the B section tower of the high-efficiency dry reactor 1. The flue gas discharged from the top of the B section tower is then subjected to dust removal by the dust collector 5. The flue gas after dust removal is purified flue gas.

[0119] 3. The fly ash after dust removal is conveyed to the intermediate weighing hopper 4-1 via the fly ash recirculation conveying device 6. After weighing in the intermediate weighing hopper 4-1, a portion of the fly ash passes through a fluidizing device (the fluidizing device is a fluidizing plate, and the fluidizing air temperature is 150℃) and enters the fly ash variable frequency unloading machine 4-3. The fly ash is then fed into the fly ash grinding and activation device 4-4 for grinding, while the other portion of the fly ash is discharged through the fly ash external discharge unloading machine 4-2. The circulation ratio of the fly ash is 25. The discharged fly ash is then conveyed to the ash silo.

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

[0121] Tests showed that the SO2 content in the purified flue gas was 5–20 mg / Nm³. 3 The HCl content is <2-6 mg / Nm³. 3 SO2 removal efficiency > 97%, HCl removal efficiency > 99%.

[0122] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for reactivated circulating deacidification of waste incineration fly ash, characterized by, The system comprises: a high-efficiency dry method reactor; the high-efficiency dry method reactor comprises an A-section tower and a B-section tower; the A-section tower and the B-section tower are connected by a bottom elbow, and a Venturi-like reduced-diameter port is arranged at the inlet of the elbow; a flue gas inlet is arranged at the top of the A-section tower; a flue gas outlet is arranged at the top of the B-section tower; a flue gas circulating device and a flue gas humidifying device are arranged in sequence on the inner wall of the A-section tower along the flow direction of the flue gas; a fly ash inlet is arranged on the side wall of the B-section tower; the flue gas of the flue gas circulating device is taken from at least one of the flue gas after a dust collector and low-temperature sulfur-free flue gas; a fly ash reactivation device; a fly ash outlet of the fly ash reactivation device is connected with the fly ash inlet of the B-section tower; 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 unloading machine is arranged in the intermediate weighing hopper; a fly ash external discharge port of the fly ash external discharge unloading machine is a fly ash external discharge port of the intermediate weighing hopper; a fly ash frequency conversion unloading machine is arranged at the bottom of the intermediate weighing hopper; a fly ash humidifying device connected with the fly ash outlet of the fly ash frequency conversion unloading machine; a fly ash outlet of the fly ash humidifying device is connected with the fly ash inlet of the B-section tower; a dust collector connected with the flue gas outlet of the B-section tower; the dust collector is provided with a flue gas outlet and a fly ash outlet; a fly ash recirculation conveying device connected with the fly ash outlet of the dust collector; a fly ash outlet of the fly ash recirculation conveying device is connected with the fly ash inlet of the fly ash reactivation device; a fly ash grinding and activating device; a fly ash inlet of the fly ash grinding and activating device is connected with the fly ash outlet of the fly ash frequency conversion unloading machine, and a fly ash outlet of the fly ash grinding and activating device is connected with the fly ash inlet of the fly ash humidifying device.

2. The system of claim 1, wherein, A deacidifying agent injection port is arranged in the high-efficiency dry method reactor for injecting a deacidifying agent.

3. The system of claim 1, wherein, A fluidizing device is arranged at the lower part of the intermediate weighing hopper; the fluidizing device is a fluidizing plate; The fly ash frequency conversion unloading machine is a screw unloading machine.

4. The system of claim 1, wherein, The fly ash humidifying device comprises a fly ash first-stage humidifying conveyor and a fly ash second-stage humidifying conveyor connected in sequence; a fly ash inlet of the fly ash first-stage humidifying conveyor is connected with the fly ash outlet of the fly ash grinding and activating device; a fly ash outlet of the fly ash second-stage humidifying conveyor is connected with the fly ash inlet of the B-section tower of the high-efficiency dry method reactor.

5. A method for fly ash reactivation and deacidification of waste incineration by using the system according to any one of claims 1-4, comprising the following steps: S1) flue gas enters the A-section tower of the high-efficiency dry method reactor, passes through the flue gas circulating device to enter the flue gas humidifying device, and is pre-cooled; S2) after the pre-cooled flue gas passes through the Venturi-like reduced-diameter port, it enters the B-section tower of the high-efficiency dry method reactor, and flue gas discharged from the top of the B-section tower is de-dusted by a dust collector; the flue gas after de-dusting is purified flue gas; S3) the de-dusted fly ash is conveyed to the fly ash reactivation device, is ground and activated, and then enters the B-section tower from the fly ash inlet on the side wall of the B-section tower.

6. The method of claim 5, wherein, In step S1), the content of SO2 in the flue gas is 200-600 mg / Nm3, and the content of HCl is 400-1200 mg / Nm3. The flue gas temperature at the flue gas inlet of the A section tower of the high-efficiency dry method reactor is 145-220 ℃; The flue gas temperature after the pre-cooling is 145-180 ℃.

7. The method of claim 5, wherein, Step S3) comprises: a) After the dust removal, a part of the fly ash is weighed by an intermediate weighing hopper, and then a part of the fly ash is sent to a fly ash grinding and activating device by a fly ash frequency conversion unloading machine for grinding, and another part of the fly ash is discharged by a fly ash external discharge unloading machine; b) After the fly ash after grinding and crushing is sent to a fly ash humidifying device for humidification, it enters the B section tower.

8. The method of claim 7, wherein, In step b), the fly ash after grinding and crushing is sent to a fly ash humidifying device for humidification, comprising: The fly ash after grinding and crushing is sent to a fly ash primary humidifying conveyor for primary humidification, and then sent to a fly ash secondary humidifying conveyor for secondary humidification; The humidity of the fly ash after secondary humidification is not less than 2%.

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