Flue gas heavy metal toxicity control system and method suitable for chain grate boiler

Abstract

The present invention discloses a flue gas heavy metal toxicity control system and method suitable for a chain grate boiler, comprising an adsorbent storage and transportation system, the adsorbent storage and transportation system being connected to a chain grate furnace through an adsorbent conveying system; the adsorbent storage and transportation system comprising an adsorbent medicine bin, the bottom outlet of the adsorbent medicine bin being connected to a buffer bin, the bottom outlet of the buffer bin being connected to a feed bin, the adsorbent storage and transportation system comprising a rotary feeding device connected to the bottom outlet of the feed bin, the outlet end of the rotary feeding device being connected to the chain grate furnace through a conveying pipeline, the side of the chain grate furnace being connected to a dust removal device through a tail flue, and the conveying pipeline being connected to a compressed air source. The present invention can effectively reduce the heavy metal toxicity in the flue gas at the outlet of the chain grate furnace.

Description

Technical Field

[0001] The invention relates to the field of heavy metal adsorption, and in particular to a flue gas heavy metal toxicity control system and method suitable for a chain grate boiler. Background Art

[0002] At present, most waste incineration power plants use chain grate furnaces as combustion boilers. The heavy metal content in the fuel (primary waste) of waste incineration power plants far exceeds the heavy metal content in traditional power plant fuels (such as coal and natural gas), so the heavy metal emission control is more stringent. The harm of heavy metals is that they cannot be decomposed by microorganisms and can be enriched in organisms to form other more toxic compounds. In the environment, heavy metals undergo geological and biological dual cycles of migration and transformation, and are eventually absorbed by the human body through channels such as the atmosphere, drinking water, and food, which have negative effects on human health, such as carcinogenicity and teratogenicity. Summary of the invention

[0003] The purpose of the present invention is to provide a flue gas heavy metal toxicity control system and method suitable for a chain grate boiler to overcome the defects of the prior art. The present invention can effectively reduce the heavy metal toxicity in the flue gas at the chain grate boiler outlet.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme:

[0005] A flue gas heavy metal toxicity control system applicable to a chain grate boiler comprises an adsorbent storage and transportation system, wherein the adsorbent storage and transportation system is connected to the chain grate furnace through an adsorbent delivery system;

[0006] The adsorbent storage and transportation system includes an adsorbent medicine bin, the bottom outlet of the adsorbent medicine bin is connected to a buffer bin, the bottom outlet of the buffer bin is connected to a feeding bin, the adsorbent storage and transportation system includes a rotary feeding device connected to the bottom outlet of the feeding bin, the outlet end of the rotary feeding device is connected to the chain furnace hearth through a conveying pipe, the side of the chain furnace hearth is connected to the dust removal equipment through a tail flue, and the conveying pipe is connected to a compressed air source.

[0007] Furthermore, a first-level dome valve is provided between the adsorbent medicine bin and the buffer bin.

[0008] Furthermore, a buffer bin material level alarm is provided on the buffer bin, and the buffer bin material level alarm is used to assist in controlling the opening or closing of the first-level dome valve.

[0009] Furthermore, a secondary dome valve is provided between the buffer bin and the feeding bin.

[0010] Furthermore, a feeding bin material level alarm is provided on the feeding bin, and the feeding bin material level alarm is used to assist in controlling the opening or closing of the secondary dome valve.

[0011] Furthermore, a bag dust collector is arranged on the top of the adsorbent medicine bin.

[0012] Furthermore, an upper pressure balance pipe is connected between the top of the adsorbent medicine bin and the top of the buffer bin, and a first control valve is provided on the upper pressure balance pipe.

[0013] Furthermore, a lower pressure balance pipe is connected between the top of the buffer bin and the top of the feeding bin, and a second control valve is arranged on the lower pressure balance pipe.

[0014] Furthermore, the outlet end of the compressed air source is also connected to the upper part and the lower part of the buffer bin.

[0015] The invention is a method for controlling heavy metal toxicity in flue gas of chain grate boilers. The adsorbent passes through the adsorbent medicine bin, buffer bin and feeding bin in sequence, enters the conveying pipeline under the action of a rotating feeding device and gravity, connects the compressed air source with the conveying pipeline, and delivers the adsorbent to the furnace of the chain grate furnace by pneumatic conveying. The adsorbent reacts with the heavy metal vapor in the flue gas in the furnace of the chain grate furnace, is agglomerated into fly ash particles, and is finally delivered to the dust removal equipment through the tail flue.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects:

[0017] The present invention delivers the adsorbent into the furnace of the chain furnace through a three-level storage and transportation system. In order to effectively separate the feeding bin and the adsorbent medicine bin and realize different pressure operation, a buffer bin is added, that is, the adsorbent medicine bin first feeds into the buffer bin, and then the buffer bin feeds into the feeding bin. This design can increase the feeding bin delivery pressure according to the distance of the delivery pipeline without worrying about the problem of excessive pressure in the adsorbent medicine bin. At the same time, a higher delivery pressure can reduce the system gas consumption rate, reduce the diameter of the delivery pipeline, and reduce investment and operating costs. Then, the heavy metal content in the furnace flue gas is reduced through adsorption and agglomeration, the heavy metal toxicity of the flue gas is reduced, and the heavy metal pollution of the waste incineration power station is reduced, which can effectively reduce the heavy metal toxicity in the flue gas at the outlet of the chain grate furnace.

[0018] Furthermore, the present invention installs a first-level dome valve and a second-level dome valve between the adsorbent medicine bin and the buffer bin and between the buffer bin and the feeding bin, respectively, and controls the valve switch state by observing the status of the buffer bin level alarm and the feeding bin level alarm, thereby controlling the pressure in the bin at different stages.

[0019] The method of the present invention can make full use of the advantage that the temperature range of the chain furnace is consistent with the adsorbent reaction, and combine with the principle of heavy metal adsorption and removal to reduce the heavy metal content in the flue gas, thus contributing to winning the battle to protect the blue sky. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The present invention is a schematic diagram of a flue gas heavy metal toxicity control system applicable to a chain grate boiler.

[0021] Among them, 1 is the adsorbent medicine bin, 2 is the buffer bin, 3 is the feeding bin, 4 is the compressed air source, 5 is the rotary feeding device, 6 is the chain furnace hearth, 7 is the tail flue, 8 is the first dome valve, 9 is the second dome valve, 10 is the lower end pressure balance pipe, 11 is the upper end pressure balance pipe, 12 is the buffer bin material level alarm, 13 is the feeding bin material level alarm, 14 is the bag filter, 15 is the boiler fuel inlet, 16 is the furnace chain grate. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in further detail below:

[0023] According to research, adsorbents such as limestone can absorb heavy metal vapor in flue gas at a specific temperature and reduce the heavy metal toxicity of flue gas. The present invention proposes a flue gas heavy metal toxicity control system suitable for chain grate boilers, see Figure 1 , including an adsorbent storage and transportation system, which is connected to the chain furnace furnace 6 through an adsorbent conveying system; the adsorbent storage and transportation system includes an adsorbent medicine bin 1, the bottom outlet of the adsorbent medicine bin 1 is connected to a buffer bin 2, the bottom outlet of the buffer bin 2 is connected to a feed bin 3, a primary dome valve 8 is arranged between the adsorbent medicine bin 1 and the buffer bin 2, a buffer bin material level alarm 12 is arranged on the buffer bin 2, and the buffer bin material level alarm 12 is used to assist in controlling the opening or closing of the primary dome valve 8, a secondary dome valve 9 is arranged between the buffer bin 2 and the feed bin 4, a feed bin material level alarm 13 is arranged on the feed bin 4, and the feed bin material level alarm 13 is used to assist in controlling the opening or closing of the secondary dome valve 9, the adsorbent A bag filter 14 is provided at the top of the medicine bin 1, an upper pressure balance pipe 11 is connected between the top of the adsorbent medicine bin 1 and the top of the buffer bin 2, and a first control valve is provided on the upper pressure balance pipe 11, a lower pressure balance pipe 10 is connected between the top of the buffer bin 2 and the top of the feeding bin 3, and a second control valve is provided on the lower pressure balance pipe 10, the adsorbent storage and transportation system includes a rotary feeding device 5 connected to the bottom outlet of the feeding bin 3, the outlet end of the rotary feeding device 5 is connected to the chain furnace hearth 6 through a conveying pipe, and the side of the chain furnace hearth 6 is connected to the dust removal equipment through a tail flue 7, and a compressed air source 4 is connected to the conveying pipe, and the outlet end of the compressed air source 4 is also connected to the upper and lower parts of the buffer bin 2.

[0024] The implementation process of the present invention is further described in detail below in conjunction with the embodiments:

[0025] (1) The adsorbent storage and transportation system can be divided into three levels in terms of vertical direction and function, with the top being the adsorbent medicine bin 1, the middle being the buffer bin 2, and the bottom being the feed bin 3;

[0026] (2) The adsorbent conveying system needs to be equipped with a compressed air source 4. The adsorbent enters the conveying pipeline at a certain flow rate under the action of the rotating feeding device 5 and gravity, and is finally delivered to the chain furnace furnace 6 by pneumatic conveying;

[0027] (3) The adsorbent undergoes an adsorption reaction with the heavy metal vapor in the flue gas in the chain furnace furnace 6 and is agglomerated into fly ash particles, which are eventually sent to the dust removal equipment through the tail flue 7.

[0028] The step (1) specifically includes:

[0029] (1-1) In order to effectively separate the feed bin and the adsorbent bin and realize different pressure operation, a buffer bin is added, that is, the adsorbent bin first feeds into the buffer bin, and then the buffer bin feeds into the feed bin. The beneficial effect of this type of design is that the feeding bin delivery pressure can be increased accordingly according to the distance of the delivery pipeline without worrying about the problem of excessive pressure in the adsorbent bin. At the same time, a higher delivery pressure can reduce the gas consumption rate of the system, reduce the diameter of the delivery pipeline, and reduce investment and operating costs;

[0030] (1-2) A first-level dome valve 8 and a second-level dome valve 9 are respectively installed between the adsorbent medicine bin 1 and the buffer bin 2 and between the buffer bin 2 and the feed bin 3. The valve switch status is controlled by observing the status of the buffer bin material level alarm 12 and the feed bin material level alarm 13, thereby controlling the pressure in the bin at different stages;

[0031] (1-3) Before the adsorbent medicine bin 1 feeds the buffer bin 2, the top bag filter (14), the upper pressure balance pipe 11 and the first dome valve 8 must be opened, and the lower pressure balance pipe 10 and the second dome valve 9 must be closed;

[0032] (1-4) Before the buffer bin 2 feeds the feed bin 3, the lower pressure balance pipe 10 and the secondary dome valve 9 must be opened, and the upper pressure balance pipe 11 and the primary dome valve 8 must be closed. The bag filter 14 can be closed or kept stationary.

[0033] The step (2) specifically includes:

[0034] (2-1) The compressed air source 4 can be dried compressed air or other high-pressure fluidizing gas. If there is no air source nearby, an air compressor and a matching dryer can be installed. The present invention does not impose any specific restrictions.

[0035] (2-2) The adsorption reaction temperature of the adsorbent and heavy metals is 700-1100°C, while the combustion temperature of the chain grate furnace is 1000-1100°C. Therefore, the adsorbent can be directly sent into the upper part of the chain grate 16 of the chain furnace furnace 6 through the delivery pipeline to carry out the adsorption reaction. Since the adsorbent is pneumatically transported, the adsorbent cannot be sent into the boiler through the boiler fuel inlet 15;

[0036] The step (3) specifically includes:

[0037] The adsorbent can effectively capture free heavy metal gases and dust in the flue gas, and form particles that can be collected through adsorption and agglomeration. The particles are collected by the original environmental dust removal devices of the waste incineration power plant, such as bag filters, electrostatic precipitators or electric bag dust collectors, effectively avoiding direct discharge into the atmosphere. The present invention does not limit and describe the characteristics of subsequent environmental dust removal devices.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Applicable to the flue gas heavy metal toxicity control system of chain grate boiler, characterized in that: It comprises an adsorbent storage and transportation system, wherein the adsorbent storage and transportation system is connected to the chain furnace furnace (6) through the adsorbent conveying system; The adsorbent storage and transportation system comprises an adsorbent medicine bin (1), the bottom outlet of the adsorbent medicine bin (1) is connected to a buffer bin (2), the bottom outlet of the buffer bin (2) is connected to a feed bin (3), the adsorbent storage and transportation system comprises a rotary feeding device (5) connected to the bottom outlet of the feed bin (3), the outlet end of the rotary feeding device (5) is connected to a chain furnace hearth (6) through a conveying pipeline, the side of the chain furnace hearth (6) is connected to a dust removal device through a tail flue (7), and the conveying pipeline is connected to a compressed air source (4); A first-level dome valve (8) is provided between the adsorbent medicine bin (1) and the buffer bin (2); The buffer bin (2) is provided with a buffer bin material level alarm (12), and the buffer bin material level alarm (12) is used to assist in controlling the opening or closing of the first-stage dome valve (8); A secondary dome valve (9) is provided between the buffer bin (2) and the feed bin (3); The feed bin (3) is provided with a feed bin material level alarm (13), and the feed bin material level alarm (13) is used to assist in controlling the opening or closing of the secondary dome valve (9); An upper pressure balance pipe (11) is connected between the top of the adsorbent medicine bin (1) and the top of the buffer bin (2), and a first control valve is provided on the upper pressure balance pipe (11); A lower pressure balance pipe (10) is connected between the top of the buffer bin (2) and the top of the feed bin (3), and a second control valve is provided on the lower pressure balance pipe (10).

2. The flue gas heavy metal toxicity control system suitable for chain grate boiler according to claim 1, characterized in that: A bag dust collector (14) is arranged on the top of the adsorbent medicine bin (1).

3. The flue gas heavy metal toxicity control system applicable to chain grate boilers according to claim 1 is characterized in that: The outlet end of the compressed air source (4) is also connected to the upper part and the lower part of the buffer bin (2).

4. A method for controlling heavy metal toxicity in flue gas of a chain grate boiler, using the heavy metal toxicity control system for flue gas of a chain grate boiler according to any one of claims 1 to 3, characterized in that: The adsorbent passes through the adsorbent medicine bin (1), the buffer bin (2) and the feeding bin (3) in sequence, and enters the conveying pipeline under the action of the rotating feeding device (5) and gravity, and the compressed air source (4) is connected to the conveying pipeline, and the adsorbent is delivered to the chain furnace hearth (6) by pneumatic conveying. The adsorbent reacts with the heavy metal vapor in the flue gas in the chain furnace hearth (6) to be agglomerated into fly ash particles, and finally delivered to the dust removal equipment through the tail flue (7).

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