Fly ash ammonium removal system with preheating device and ammonium removal method

文档序号:1347342 发布日期:2020-07-24 浏览:24次 中文

阅读说明:本技术 一种具有预热装置的粉煤灰除铵系统及除铵方法 (Fly ash ammonium removal system with preheating device and ammonium removal method ) 是由 原志敏 张国柱 谷小兵 白玉勇 张钧泰 文钰 于 2020-05-06 设计创作,主要内容包括:本发明提供了一种具有预热装置的粉煤灰除铵系统及除铵方法,除铵系统包括加药装置、预热装置、混合反应装置、干化装置和尾气净化装置;加药装置用于配置在混合反应装置中与粉煤灰中铵盐反应的碱液;预热装置利用蒸汽凝结水热量加热加药装置配置好的碱液;在混合反应装置内,粉煤灰与经过预热装置加热的碱液混合反应,促进氨气的释放;干化装置利用电厂蒸汽加热粉煤灰,促进粉煤灰中水分蒸发;尾气净化装置处理混合反应装置和干化装置产生的尾气。该系统利用蒸汽凝结水对碱液进行加热处理,能够有效地提高碱液与铵盐的反应效率,减少粉煤灰在系统内的停留时间,提高粉煤灰处理能力;同时梯级利用蒸汽及凝结水热量,提高能源利用率。(The invention provides a fly ash ammonium removal system with a preheating device and an ammonium removal method, wherein the ammonium removal system comprises a dosing device, a preheating device, a mixing reaction device, a drying device and a tail gas purification device; the dosing device is used for being configured in the mixed reaction device to react with the alkali liquor in the ammonium salt in the fly ash; the preheating device heats the alkali liquor prepared by the dosing device by utilizing the heat of the steam condensed water; in the mixing reaction device, the fly ash and the alkali liquor heated by the preheating device are mixed and reacted to promote the release of ammonia gas; the drying device heats the fly ash by using steam of a power plant to promote the evaporation of water in the fly ash; the tail gas purification device is used for treating tail gas generated by the mixed reaction device and the drying device. The system utilizes the steam condensate water to heat the alkali liquor, can effectively improve the reaction efficiency of the alkali liquor and the ammonium salt, reduce the retention time of the fly ash in the system and improve the fly ash treatment capacity; meanwhile, the heat of the steam and the condensed water is utilized in a gradient manner, so that the energy utilization rate is improved.)

1. A fly ash ammonium removal system with a preheating device is characterized by comprising a dosing device, a preheating device, a mixing reaction device, a drying device and a tail gas purification device;

the chemical adding device is used for preparing alkali liquor which reacts with ammonium salt in the fly ash in the mixed reaction device;

the preheating device heats the alkali liquor prepared by the dosing device by utilizing the heat of the steam condensed water;

in the mixing reaction device, the fly ash and the alkali liquor heated by the preheating device are mixed and reacted to promote the release of ammonia gas;

the drying device utilizes steam of a power plant to heat the fly ash so as to promote the evaporation of water in the fly ash;

and the tail gas purification device is used for treating tail gas generated by the mixed reaction device and the drying device.

2. The system of claim 1, wherein the drying device comprises a jacket, and the preheating device comprises a heating coil;

the jacket comprises a first inlet end, a first outlet end and a second outlet end;

the first inlet end is communicated with a steam outlet of the steam turbine;

the first outlet end and the second outlet end are used for discharging steam condensate;

the heating coil comprises a second inlet end and a third outlet end;

the first outlet end is communicated with the second inlet end, and the second outlet end and the third outlet end are communicated with a condensation water pipeline at the rear end of the steam turbine.

3. The system for removing ammonium from fly ash with a preheating device according to claim 2, wherein the steam condensate in the heating coil indirectly heats the configured alkali liquor in the preheating device.

4. The system for removing ammonium from fly ash according to claim 1, wherein the drying device and the fly ash conveying device in the mixing reaction device are horizontal paddles.

5. The system for removing ammonium from fly ash according to claim 1, wherein a spraying device is disposed in the mixing reaction device, and the spraying device sprays preheated alkali liquor into the mixing reaction device to promote mixing and reaction of the alkali liquor and fly ash.

6. The fly ash ammonium removal system with the preheating device as claimed in claim 1, wherein the tail gas treatment device comprises a dust removal device and a spray purification tower; and tail gas discharged by the mixing reaction device and the drying device is connected to the spray purification tower through the dust removal device.

7. The system for removing ammonium from fly ash with a preheating device as claimed in claim 1, wherein the tail gas outlet ends of the mixing reaction device and the drying device are provided with negative pressure fans.

8. A fly ash ammonium removal method, which is characterized in that the method adopts the fly ash ammonium removal system with the preheating device as claimed in any one of claims 1 to 7, and comprises the following steps:

heating water or prepared alkali liquor;

mixing the heated water or alkali liquor with the fly ash, and releasing tail gas containing ammonia gas from the fly ash;

drying the coal ash after releasing the ammonia gas to obtain dry coal ash;

and (4) carrying out tail gas treatment on tail gas generated in the mixed reaction process and the drying process.

9. The method for removing ammonium from fly ash according to claim 8, wherein the fly ash is dried by steam from a steam turbine;

and heating the alkali liquor by using high-temperature condensed water generated after the fly ash is dried.

10. The ammonium removal method for fly ash according to claim 8, wherein the mass ratio of fly ash to alkali liquor is controlled to be 10: 1-20: 1.

Technical Field

The invention relates to the technical field of solid waste recycling, in particular to a coal-fired power plant fly ash quality optimization system.

Background

Fly ash is one of the main solid wastes generated by coal-fired power plants, and the annual output is huge. One ton of raw coal is combusted, and 250-300 kg of fly ash is expected to be generated. Fly ash disposal difficulties are becoming more and more acute for coal fired power plants. Through decades of research and application, the fly ash has certain practical application achievements in the aspects of building engineering, agricultural utilization, heavy metal extraction and the like. Among them, the fly ash as an additive for cement or concrete is the current mainstream utilization mode.

At present, the denitration improvement of coal-fired power plants in China is close to the end sound. The content of nitrogen oxides in flue gas is reduced by adopting SCR technology (the technology takes urea or ammonia water as a reducing agent) in a large number of coal-fired units. However, during the actual operation of the SCR process, NH inevitably occurs3And escape. SO generated by burning and catalytic oxidation of S in raw coal3With escaped NH3Side reaction occurs to generate a large amount of NH4HSO4And (NH)4)2SO4. The two ammonium salts have strong adhesiveness, so that the ammonium salts are adhered and dispersed in the fly ash, and the quality and the resource utilization of the fly ash are influenced.

In the actual application process of the ammonium salt-containing fly ash in the field of cement concrete, phenomena of bubbling with irritation after pouring, prolonging of cement setting time, expansion of a mold after pouring of a test piece or an engineering entity and the like can occur, so that the concrete can not obtain the required performance, and even the quality and the service life of the concrete are threatened. Meanwhile, the released ammonia gas can also harm the health of constructors or residents. The phenomenon restricts the resource utilization of the fly ash.

Disclosure of Invention

The first purpose of the invention is to provide a fly ash ammonium removal system with a preheating device, which can solve the problem of poor resource utilization safety of fly ash;

the second purpose of the invention is to provide a fly ash ammonium removal method, which adopts the fly ash ammonium removal system with the preheating device.

The invention provides a fly ash ammonium removal system with a preheating device, which comprises a dosing device, the preheating device, a mixing reaction device, a drying device and a tail gas purification device, wherein the dosing device is connected with the preheating device;

the chemical adding device is used for preparing alkali liquor which reacts with ammonium salt in the fly ash in the mixed reaction device;

the preheating device heats the alkali liquor prepared by the dosing device by utilizing the heat of the steam condensed water;

in the mixing reaction device, the fly ash and the alkali liquor heated by the preheating device are mixed and reacted to promote the release of ammonia gas;

the drying device utilizes steam of a power plant to heat the fly ash so as to promote the evaporation of water in the fly ash;

and the tail gas purification device is used for treating tail gas generated by the mixed reaction device and the drying device.

Preferably, the drying device comprises a jacket, and the preheating device comprises a heating coil;

the jacket comprises a first inlet end, a first outlet end and a second outlet end;

the first inlet end is communicated with a steam outlet of the steam turbine;

the first outlet end and the second outlet end are used for discharging steam condensate;

the heating coil comprises a second inlet end and a third outlet end;

the first outlet end is communicated with the second inlet end, and the second outlet end and the third outlet end are communicated with a condensation water pipeline at the rear end of the steam turbine.

Preferably, the steam condensate in the heating coil indirectly heats the prepared alkali liquor in the preheating device.

Preferably, the drying device and the fly ash conveying device in the mixing reaction device are horizontal paddles.

Preferably, a spraying device is arranged in the mixing reaction device, and the spraying device sprays preheated alkali liquor into the mixing reaction device to promote mixing and reaction of the alkali liquor and the fly ash.

Preferably, the tail gas treatment device comprises a dust removal device and a spray purification tower; and tail gas discharged by the mixing reaction device and the drying device is connected to the spray purification tower through the dust removal device.

Preferably, the tail gas outlet ends of the mixing reaction device and the drying device are provided with negative pressure fans.

A fly ash ammonium removal method, which adopts the fly ash ammonium removal system with a preheating device as described above, and comprises the following steps:

heating water or prepared alkali liquor;

mixing the heated water or alkali liquor with the fly ash, and releasing tail gas containing ammonia gas from the fly ash;

drying the coal ash after releasing the ammonia gas to obtain dry coal ash;

and (4) carrying out tail gas treatment on tail gas generated in the mixed reaction process and the drying process.

Preferably, the fly ash is dried by steam of a steam turbine;

and heating the alkali liquor by using high-temperature condensed water generated after the fly ash is dried.

Preferably, the mass ratio of the fly ash to the alkali liquor is controlled to be 10: 1-20: 1.

Has the advantages that:

the ammonium removal system provided by the invention can remove ammonium salt in the fly ash and treat the finally generated tail gas containing ammonia gas. The system utilizes the steam condensate water to heat the alkali liquor, can effectively improve the reaction efficiency of the alkali liquor and the ammonium salt, reduce the retention time of the fly ash in the system and improve the fly ash treatment capacity; meanwhile, the heat of the steam and the condensed water is utilized in a gradient manner, so that the energy utilization rate is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of a flow structure of a fly ash ammonium removal system with a preheating device according to an embodiment of the present invention;

description of reference numerals:

1: a dosing device; 2: a preheating device; 3: a mixing reaction device; 4: a drying device; 5: tail gas purification processing apparatus.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. Furthermore, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, the present embodiment provides a fly ash ammonium removal system with a preheating device, which includes a dosing device 1, a preheating device 2, a mixing reaction device 3, a drying device 4, and a tail gas purification device 5.

The chemical adding device 1 is used for preparing alkali liquor which reacts with ammonium salt in the fly ash in the mixing reaction device 3.

The preheating device 2 heats the prepared alkali liquor in the dosing device 1 by utilizing the heat of the steam condensed water.

In the mixing reaction device 3, the fly ash and the alkali liquor heated by the preheating device 2 are mixed and reacted to promote the release of ammonia gas.

The drying device 3 utilizes steam of a power plant to heat the fly ash so as to promote the evaporation of water in the fly ash.

The specific connection relationship of each part is as follows:

the outlet end of the dosing device 1 is communicated with the inlet end of the preheating device 2, the outlet end of the preheating device 2 is communicated with the spraying device of the mixing reaction device 3, the coal ash outlet end of the mixing reaction device 3 is butted with the coal ash inlet end of the drying device 4, and the tail gas outlets of the mixing reaction device 3 and the drying device 5 are communicated with the tail gas purification device 5.

In this embodiment, there is also provided a working process of the ammonium removal system:

carrying out alkali liquor proportioning in the dosing device 1, conveying the proportioned alkali liquor to the preheating device 2 by the dosing device 1, spraying the alkali liquor heated by the preheating device 2 through a spraying device in the mixed reaction device 3, mixing the alkali liquor and the fly ash in the mixed reaction device 3, carrying out mixed reaction to generate ammonia gas, and finally conveying the fly ash after the mixed reaction to the drying device 4 for drying treatment. The tail gas purification device 5 can treat the tail gas of the mixing reaction device 3 and the drying device 4.

It should be noted that, when water is used to remove ammonium salt, the difference from using alkali liquor to remove ammonium salt is mainly that alkali liquor needs to be proportioned in the dosing device 1, water does not need to be proportioned, and the dosing device 1 only conveys water to the preheating device 2.

The ammonium removal system in the embodiment can remove ammonium salt in the fly ash and treat finally generated ammonia gas. The system utilizes the steam condensate water to heat the alkali liquor, can effectively improve the reaction efficiency of the alkali liquor and the ammonium salt, reduce the retention time of the fly ash in the system and improve the fly ash treatment capacity; meanwhile, the heat of the steam and the condensed water is utilized in a gradient manner, so that the energy utilization rate is improved.

Specifically, the drying device 4 comprises a jacket, the preheating device 2 comprises a heating coil, and the jacket comprises a first inlet end, a first outlet end and a second outlet end. The heating coil includes a second inlet end and a third outlet end.

The first inlet end is communicated with a steam outlet of the steam turbine, and the first outlet end and the second outlet end are used for discharging steam condensate. The first outlet end is communicated with the second inlet end, and the second outlet end and the third outlet end are communicated with a condensation water pipeline at the rear end of the steam turbine.

In the embodiment, the drying device 4 and the preheating device 2 can utilize the steam waste heat of the coal power plant through the connection relationship, so that the energy utilization rate is improved, and the operation cost is reduced.

Specifically, the jacket can realize the utilization of heat in steam of the steam turbine, and condensed water obtained after heat exchange of the steam in the jacket is partially conveyed to the preheating device 2 to heat alkali liquor or water, and the other part returns to a condensed water pipeline at the rear end of the steam turbine. The condensed water after heat exchange in the preheating device 2 finally returns to the condensed water pipeline at the rear end of the steam turbine.

The conveying devices in the mixing reaction device 3 and the drying device 4 are horizontal paddles.

The spraying device is arranged at the top of the mixing reaction device 3, and the fly ash conveying device is arranged at the bottom of the mixing reaction device 3.

The horizontal paddle in the mixing reaction device 3 can improve the mixing and reaction efficiency between the alkali liquor or water and the fly ash through rotation, and pushes the fly ash to move towards the drying device 4.

The mixing reaction device 3 is connected with the drying device 4 through a screw conveyor, and the reacted fly ash is conveyed into the indirect drying device 4 through the screw conveyor to remove moisture.

The tail gas treatment device 5 comprises a dust removal device and a spray purification tower, and the mixed reaction device 3 and the drying device 4 are both connected to the spray purification tower through the dust removal device.

Dust collector can get rid of the dust in the tail gas, and the tail gas after the dust removal is through spraying purification tower recovery water and ammonia, and remaining tail gas is discharged.

And the tail gas outlet ends of the mixing reaction device 3 and the drying device 4 are provided with negative pressure fans. The negative pressure fan can enable the mixed reaction device 3 and the drying device 4 to be in a negative pressure device, and provides power for a tail gas treatment device for tail gas.

In this embodiment, there is also provided a fly ash ammonium removal method using the fly ash ammonium removal system with a preheating device as described above, which includes the following steps:

heating water or prepared alkali liquor;

mixing the heated water or alkali liquor with the fly ash, and releasing tail gas containing ammonia gas from the fly ash;

drying the coal ash after releasing the ammonia gas to obtain dry coal ash;

and (4) carrying out tail gas treatment on tail gas generated in the mixed reaction process and the drying process.

Specifically, the fly ash is dried by steam of a steam turbine, and the alkali liquor is heated by high-temperature condensed water generated after the fly ash is dried by the steam.

The mass ratio of the fly ash to the alkali liquor is controlled to be 10: 1-20: 1.

For further explanation of the above method, the present embodiment provides the specific steps of the fly ash ammonium removal system in the actual production process:

1) the alkali liquor (or water) prepared by the dosing device 1 is heated in the preheating device 2, and the preheating temperature of the alkali liquor or water is 40-70 ℃.

2) High-temperature alkali liquor (or water) is sprayed by a spraying system in the mixing reaction device 3 and is mixed with the fly ash conveyed into the mixing reaction device 3 by a belt;

3) the mass ratio of the fly ash to the alkali liquor (or water) can be controlled by regulating the speed of the belt and the spraying amount, and the mass ratio of the fly ash to the alkali liquor (or water) is 10: 1-20: 1;

4) a horizontal paddle is arranged in the mixing reaction device 3, and the mixing and reaction of the fly ash and the alkali liquor (or water) are accelerated by rotation, and the fly ash is pushed to move forwards;

5) the fly ash after reaction is sent into a drying device 4 through a screw conveyor to remove water;

6) the shell of the drying device 4 comprises a jacket, and steam introduced into the jacket is used for heating wet coal ash;

7) the horizontal paddle is also arranged in the drying device 4, and the water evaporation is accelerated and the fly ash is pushed to move forwards through rotation;

8) the heating medium in the drying device 4 is steam at the rear end of a steam turbine;

9) the condensed water of the steam discharged by the drying device 4 is divided into two paths, wherein one path is introduced into the preheating device 2 to heat the alkali liquor (or water);

10) the steam condensate discharged by the preheating device 2 is mixed with the other path of steam condensate discharged by the drying device 4 and then is led to a condensate pipeline at the rear end of the steam turbine through a pipeline;

11) maintaining negative pressure in the mixing reaction device 3 and the drying device 4 through a fan, collecting tail gas of the two devices, removing dust and purifying;

12) and recovering water and ammonia gas from the tail gas after dust removal through a spray purification tower, and discharging the residual tail gas.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

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