CN121371952A - An integrated moving bed desulfurization device for vertical boiler systems - Google Patents

Abstract

The invention discloses a built-in moving bed desulfurization device for a vertical boiler system. A plurality of inserted sheet type moving beds are arranged in the middle temperature Duan Shuxiang of the boiler shell, each inserted sheet type moving bed comprises an inverted cone-shaped hollow shell made of a porous plate, at least one pneumatic conveying feeding port is arranged on the shell, the pneumatic conveying feeding port is used for conveying granular desulfurizing agent filler into a ventilation shell, a byproduct discharging screw conveyor is arranged in the inner bottom of the shell, and a discharging pipe is arranged at the bottom of one side of the shell corresponding to the byproduct discharging screw conveyor. The device can be directly arranged in the vertical boiler shell, and only one set of desulfurizing agent storage and transportation circulating discharging system is required to be arranged outside the boiler.

Description

Built-in moving bed desulfurization device for vertical boiler system

Technical Field

The invention relates to the technical equipment field of boiler flue gas desulfurization treatment. In particular to a built-in moving bed desulfurization device for a vertical boiler system, which is mainly used for vertical boiler flue gas desulfurization with low concentration level (< 200mg/m < 3 >), and can be directly arranged in a middle-temperature or low-temperature section (< 400 ℃ for use) in the vertical boiler, and the standard emission of flue gas can be realized without additionally arranging other desulfurization facilities on a boiler outlet flue. Compared with the traditional boiler flue gas desulfurization technology with low concentration level (< 200mg/m < 3 >), the method has the remarkable advantages of small occupied area, simple system and low construction and operation cost.

Background

SO ₂ is a gaseous pollutant with larger content and wider influence surface in atmospheric pollutants, and is mainly from the combustion of fossil fuels (coal, petroleum and natural gas) and the roasting and smelting processes of sulfide ores.

The control technology for SO ₂ is mainly divided into a pre-combustion desulfurization technology (mainly referred to as raw coal purification and gas fine desulfurization), a clean combustion desulfurization technology (molded coal sulfur fixation, circulating fluidized bed combustion desulfurization, coal water slurry and the like) and a post-combustion desulfurization technology (terminal treatment).

According to the ultra-low emission standards of electric power, metallurgy and cement building material industries which are released successively in the country in recent years, boiler flue gas desulfurization is becoming stricter, and most industrial enterprises desulfurization purification projects all require flue gas to realize the ultra-low emission requirement that the sulfur dioxide concentration is lower than 35mg/Nm ³.

With the annual increase of the environmental pressure in China, the national emission requirements are further tightened, and the flue gas desulfurization technology is rapidly developed. At present, the types of flue gas desulfurization technology reach dozens, and flue gas desulfurization is divided into three main types of desulfurization technologies, namely a wet process, a semi-dry process and a dry process according to whether water is added in the desulfurization process or not and the dry and wet forms of desulfurization products. The main stream flue gas desulfurization process with wider application at present is briefly described as follows:

The wet process adopts an absorption tower form, and flue gas enters the absorption tower and then fully contacts and reacts with alkaline solution to achieve the desulfurization effect. The wet washing method has good acid gas removal effect and small absorbent consumption. The method has the defects of complex flow, more matched equipment, tail gas tailing phenomenon, and the requirement of arranging a secondary purification device to achieve ultra-clean emission and matched sewage treatment.

The semi-dry desulfurization is to spray the absorbent into a reaction tower, and the SO ₂ gas reacts with the absorbent, and simultaneously, the moisture in the absorbent is evaporated by utilizing the waste heat of the flue gas, the absorbent and pollutants perform sufficient mass and heat transfer, SO that the efficiency is improved, and meanwhile, the reaction product can be dried, and the product is discharged in a dry solid form. The semi-dry process is mature and has simple equipment. The method has the advantages of high purification efficiency, easy treatment of products, control of system temperature and humidity, good adaptability to load fluctuation, adjustable absorbent dosage according to the concentration of pollutants in the flue gas, and low water consumption.

The dry desulfurization process is to spray lime powder/sodium carbonate/sodium bicarbonate into a flue of a system or a desulfurization reactor through a spraying system, contact and react with acid gas to generate solid compounds, and then trap the solid compounds together with fly ash by a dry dust collector and other equipment. The combined process has the greatest advantages of simple system, convenient maintenance, low cost, small occupied area, no waste water and no tailing phenomenon of flue gas after desulfurization.

A new dry desulfurization technology has also emerged in recent two years, namely a fixed bed dry desulfurization process, which adopts a fixed bed-like technology, and uses a desulfurizing agent (lime, sodium bicarbonate, magnesium oxide, etc.) and shaped particles of a catalyst to be filled in a desulfurization reactor, and after flue gas flows, SO ₂ therein is oxidized into SO ₃ and is reacted and solidified into calcium sulfate solid. The process has no waste water, simple operation, wide application range of flue gas temperature (not more than 400 ℃), small occupied area and low investment.

Compared with the wet desulfurization process and the semi-dry desulfurization process with complex process facilities, the dry desulfurization process has the advantages of low investment and operation cost, no waste water and no white smoke, is particularly suitable for treating low-sulfur smoke, but has the defects that aiming at a boiler smoke desulfurization project with large flow and low concentration, the filling amount of a desulfurizing agent is relatively large, partial projects are also uneven in reaction of the desulfurizing agent in a filler layer due to uneven air flow, and the utilization rate of active ingredients of the desulfurizing agent is low.

Disclosure of Invention

In order to overcome the defects, the invention aims to provide a built-in moving bed desulfurization device for a vertical boiler system, which is particularly suitable for large-flow low-concentration boiler flue gas desulfurization, has a plurality of advantages of fixed bed dry desulfurization, and can realize the functions of recycling online desulfurizing agents and replacing the desulfurizing agents as required.

In order to achieve the above object, the built-in moving bed desulfurization device for a vertical boiler system of the present invention is characterized in that a plurality of insert moving beds are provided at a middle temperature Duan Shuxiang inside a boiler housing, each of the insert moving beds comprises:

An inverted cone-shaped funnel-shaped hollow shell made of a porous plate;

The shell is provided with at least one pneumatic conveying feed inlet, granular desulfurizing agent filler is conveyed into the hollow part of the ventilation shell, a byproduct discharge screw conveyor is arranged at the inner bottom of the shell, and a discharge pipe is arranged at the bottom of one side of the shell corresponding to the byproduct discharge screw conveyor.

Further, a desulfurizing agent storage and transportation circulation discharging system is arranged outside the boiler shell and at least comprises a desulfurizing agent bin, wherein a pneumatic conveying device is arranged at a discharging hole at the bottom of the desulfurizing agent bin, and the pneumatic conveying device is communicated with a pneumatic conveying feeding hole through a feeding pneumatic conveying pipeline;

The desulfurization agent bin is characterized by further comprising a lifting machine, wherein a feed inlet is formed in the bottom of the lifting machine, the feed inlet of the lifting machine is communicated with a discharge pipe of the byproduct discharge screw conveyor through a discharge pipe, a discharge outlet is formed in the upper portion of the lifting machine, and the discharge outlet of the lifting machine is arranged corresponding to the feed inlet of the desulfurization agent bin.

Further, the pneumatic conveying device consists of a Venturi transmitter and a feeding Roots blower.

Further, an inspection manhole door is arranged on one side of each layer of moving bed frame.

Further, a star discharger and a desulfurizing agent weighing device are arranged at the bottom of the desulfurizing agent bin.

Further, the desulfurizing agent filler is a granular calcium-based desulfurizing agent.

Further, the flow direction of the flue gas is the same as the flow direction of the desulfurizing agent.

Compared with the conventional boiler flue gas desulfurization technologies such as circulating fluidized bed CFB desulfurization, sodium bicarbonate SDS desulfurization, and calcium-based ultrafine powder dry desulfurization, the invention has the following obvious advantages, and is more suitable for being applied to various low-concentration (< 200mg/m ³) horizontal vertical boiler flue gas desulfurization projects.

1. The device can be directly arranged in the vertical boiler shell, and only 1 set of desulfurizing agent storage and transportation circulating discharging system is required to be arranged outside the boiler, compared with the traditional desulfurizing technology, a desulfurizing tower and a cloth bag dust remover are not required to be arranged, so that project occupation is saved to a great extent, and construction cost is low;

2. The device can be directly arranged in the vertical boiler shell, so that the design, the manufacture and the installation of the desulfurization device and the boiler equipment can be easily realized, and the whole construction period is saved;

3. The purification principle of the invention adopts a dry adsorption purification mode of the granular calcium-based desulfurizing agent, does not introduce any other substances, and avoids the influence of introducing new materials into the flue gas to a flue gas system due to other desulfurization processes such as wet spraying, semi-dry spraying slurry, dry spraying powder and the like;

4. the device adopts a conical vertically arranged plug-in type moving bed structure, the structural design of the moving bed is flexible, different plug-in modules and the number of layers of plug-in stuffing can be designed according to the size of a boiler shell and the sulfur concentration in flue gas, and the device has obvious advantages in the aspects of field arrangement and on-line switching control;

5. the device is wide in applicable smoke volume range, the overall dimension of the inserted sheet type moving bed can be designed according to the scale of the smoke volume treated by the project, and the device is not limited by the scale of the smoke volume in theory;

6. The purifying system has a relatively simple structure, other transmission equipment is not required except a discharging screw conveyor in the moving bed, the equipment is not required to be attended during normal operation, and the workload of personnel inspection and maintenance is extremely low;

7. The device has the advantages of small system resistance, less transmission equipment and low energy consumption;

8. the device of the invention has no waste water generation and no secondary pollution, and the waste granular desulfurizing agent after adsorption saturation can be directly packaged at the lower part of the desulfurizing agent bin or transported by an automobile.

9. After the fume is purified by the device, the fume is still dry fume, and the system does not need corrosion prevention and has no phenomenon of white fume.

Drawings

Fig. 1 is a schematic elevation view of the present invention.

Fig. 2 is a schematic top view of the present invention.

FIG. 3 shows a device according to the invention schematic cross-section of the moving bed.

FIG. 4 is a schematic diagram of a porous plate according to the present invention.

In the figure:

1. the boiler comprises a boiler body, 2, a granular calcium-based desulfurizing agent, 3, a gas inlet and outlet porous plate, 4, a pneumatic conveying feed inlet, 5, a byproduct discharge screw conveyor, 6, a moving bed steel frame, 7, a feeding pneumatic conveying pipeline, 8, a discharge pipeline, 9, a bucket elevator, 10, a desulfurizing agent bin, 11, a star discharger, 12, a desulfurizing agent weighing device, 13, a venturi transmitter, 14, a feeding Roots blower, 15, an outer discharge outlet pipe, 16 and a guide chute in a filler plugboard;

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

The terms "first," "second," and the like, 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, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present invention, unless explicitly stated and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, directly connected, or indirectly connected through an intermediary, or may be in communication with the interior of two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

The invention relates to a built-in moving bed desulfurization device for a vertical boiler system, wherein a plurality of insert-type moving beds are vertically arranged in a middle temperature section (for example, between a superheater and an evaporator) in a shell of a boiler (1), and each insert-type moving bed comprises:

The hollow shell is formed by arranging an inner inverted cone-shaped air inlet and outlet porous plate and an outer inverted cone-shaped air inlet and outlet porous plate at intervals;

The shell is provided with at least one pneumatic conveying feed inlet 4, 4 pneumatic conveying feed inlets in fig. 2, a granular desulfurizing agent filler 2 for conveying into the hollow part of the ventilation shell, a byproduct discharge screw conveyor is arranged at the inner bottom of the shell, and a discharge pipe is arranged at the bottom of one side of the shell corresponding to the byproduct discharge screw conveyor.

The external discharge system for the desulfurizing agent storage and transportation circulation is arranged outside the boiler shell and comprises a feeding pneumatic conveying pipeline (7), a discharging pipeline (8), a bucket elevator (9), a desulfurizing agent bin (10), a star discharger (11), a desulfurizing agent weighing device (12), a Venturi transmitter (13), a feeding Roots blower (14), an external discharge outlet pipe (15) and the like.

The built-in moving bed desulfurization apparatus for a vertical boiler system according to the present invention will be further described with reference to fig. 1 to 4:

after passing through the high temperature evaporator, denitration and other facilities, the temperature of the boiler flue gas is reduced to about 330-400 ℃, and a built-in moving bed desulfurization device is arranged inside the boiler flue gas depending on the boiler body shell in the temperature zone.

The boiler is characterized in that a moving bed steel structure frame (6) is arranged in the boiler shell and is used for building and supporting the inserted sheet type moving bed of the multilayer structure.

According to the concentration of sulfur dioxide in boiler flue gas, an inverted cone-shaped funnel-shaped hollow shell made of two layers or three layers of porous plates is arranged. The sulfur dioxide concentration is lower than 100mg/m3, two layers are generally arranged, the sulfur dioxide concentration is higher than 100mg/m3, and three layers are generally arranged.

Each layer of inserted sheet formula moving bed is from top feeding, from the bottom ejection of compact, realizes online material flow, circulation, update. The top feeding adopts a pneumatic conveying mode, and the bottom discharging adopts a spiral conveying mode. The power medium of pneumatic conveying is derived from compressed air generated by a feeding Roots blower (14). The spiral conveyor (5) directly transfers the desulfurizing agent to the bucket elevator (9), and then the bucket elevator (9) is used for conveying the desulfurizing agent back into the desulfurizing agent bin (10).

The lower part of the desulfurizing agent bin (10) is discharged through 1 star discharger (11), and is connected with 1 desulfurizing agent weighing device (12) for metering the dosage of desulfurizing agent. The metered desulfurizing agent is sent into the moving bed layer in the boiler through a lower Venturi transmitter (13) and a feeding pipeline (7).

In the running process of the desulfurization device, the concentration level of sulfur dioxide can be monitored in real time according to the CEMS on-line detection device at the inlet and the outlet, the action of a moving bed can be properly reduced when the device runs at the low concentration level for a long time, the circulation amount and the fresh material updating amount are reduced, and the circulation amount and the fresh material adding amount are improved when the device runs at the high concentration sulfur dioxide concentration level, so that the purpose of ultra-low emission is realized.

The desulfurizing principle of the desulfurizing agent of the device is as follows:

The main reaction formula of the desulfurization of the granular calcium-based desulfurizing agent is SO ₂+ 1/2 O₂+Ca(OH)₂→ CaSO₄+ H₂ O. The method is technically realized by using a purifying device with a fixed bed or intermittent moving bed structure to be filled with a granular desulfurizing agent, and after flue gas flows, sulfur dioxide in the desulfurizing agent is reacted and solidified into calcium sulfate (gypsum) solid.

Selecting a granular calcium-based desulfurizing agent:

the device of the invention is prepared by using a common granular calcium-based desulfurizing agent in the market, wherein the desulfurizing agent is prepared by taking calcium hydroxide as a main active component and adding other accelerators. The sulfur dioxide removal agent has good sulfur dioxide removal effect within a temperature window of 50-400 ℃.

The whole process does not use water and does not produce waste water. The operation control process is one step, and the process is simple.

The desulfurization effect can be achieved by adjusting the contact time according to the requirement, 100% removal can be achieved, the desulfurization device is insensitive to short-time fluctuation of flue gas conditions and is also insensitive to flue gas temperature, and the desulfurization device is almost suitable for all flue gas conditions.

The present invention has been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention. Many other changes and modifications may be made without departing from the spirit and scope of the invention and should be considered as within the scope of the invention.

In the description of the present specification, a particular feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments or examples.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (7)

1. A built-in moving bed desulfurization device for a vertical boiler system, characterized in that multiple insert-type moving beds are vertically arranged in the intermediate temperature section inside the boiler shell; each of the insert-type moving beds comprises: A hollow, inverted conical funnel-shaped shell made of porous plate; At least one pneumatic conveying inlet is provided on the shell for conveying granular desulfurizing agent filler into the hollow part of the ventilated shell; a by-product discharge screw conveyor is provided at the bottom of the shell, and a discharge pipe is provided on one side of the bottom corresponding to the by-product discharge screw conveyor. 2. The built-in moving bed desulfurization device for a vertical boiler system as described in claim 1, characterized in that a desulfurizing agent storage, transportation, circulation and discharge system is provided outside the boiler shell, including at least: a desulfurizing agent silo, and a pneumatic conveying device is provided at the bottom outlet of the desulfurizing agent silo, wherein the pneumatic conveying device is connected to the pneumatic conveying inlet through a pneumatic conveying pipeline. It also includes an elevator, with a feed inlet at the bottom of the elevator, which is connected to the discharge pipe of the by-product discharge screw conveyor via a discharge pipe; and a discharge outlet at the top of the elevator, which corresponds to the feed inlet of the desulfurizing agent silo. 3. The built-in moving bed desulfurization device for a vertical boiler system as described in claim 1, characterized in that the pneumatic conveying device consists of a Venturi transmitter and a feeding Roots blower. 4. The built-in moving bed desulfurization device for a vertical boiler system as described in claim 2, characterized in that an inspection manhole is provided on one side of each moving bed frame. 5. The built-in moving bed desulfurization device for a vertical boiler system as described in claim 1, characterized in that a star-shaped unloader and a desulfurizing agent weighing device are provided at the bottom of the desulfurizing agent silo. 6. The built-in moving bed desulfurization device for a vertical boiler system as described in claim 1, characterized in that the desulfurizing agent filler is a granular calcium-based desulfurizing agent. 7. The built-in moving bed desulfurization device for a vertical boiler system as described in claim 1, characterized in that the flue gas flow direction is the same as the desulfurizing agent flow direction.