Flue bottom plate anti-corrosion device

Abstract

The present invention relates to the field of industrial energy conservation and environmental protection technology, and specifically to a flue bottom plate anti-corrosion device. The flue bottom plate anti-corrosion device comprises a flue bottom plate and a flue side plate, the flue bottom plate and the flue side plate are evenly coated with a glass flake anti-corrosion layer, a carbon brick anti-corrosion layer is evenly applied on the glass flake anti-corrosion layer, a spray water pipe is arranged above the carbon brick anti-corrosion layer and in a vertical direction of the flue, and a plurality of nozzles at an oblique downward angle are evenly arranged on the spray water pipe. The present invention solves the problem of acid condensation in flue gas, which continuously drips onto the flue bottom plate and causes corrosion, and prolongs the service life of the flue.

Description

Technical Field

[0001] The invention relates to the technical field of industrial energy conservation and environmental protection, and in particular to a flue bottom plate anti-corrosion device, which can be used for anti-corrosion treatment of a flue bottom plate between a low-temperature economizer and an absorption tower. Background Art

[0002] China's energy structure is characterized by being rich in coal, poor in oil and little gas, which determines that the energy required for domestic industrial production comes mainly from coal, accounting for about 70% of total energy consumption.

[0003] The exhaust gas of coal-fired boilers has the characteristics of high temperature, high concentration of pollutants such as SO2 and nitrogen oxides, and high dust content. In order to solve the problem of boiler flue gas emission pollution, a large number of technical measures have been taken in recent years to reduce the emission of pollutants such as smoke, SO2, and nitrogen oxides. The dust collector, flue gas desulfurization system (FGD), and flue gas denitrification system (SCR) have been added and modified, and the overall emission level has been greatly reduced. At the same time, in order to recover the heat in the flue gas, a low-temperature economizer was added to recover the waste heat of the flue gas, which has achieved good results.

[0004] However, since the low-temperature economizer recovers the heat in the flue gas, the flue gas temperature is reduced. When the flue gas temperature is lower than the acid dew point temperature, the acid in the flue gas will condense and condense, and under the action of flue gas flow velocity and gravity, it will continuously drip onto the flue bottom plate downstream of the low-temperature economizer. As the acid dew continues to accumulate, its corrosiveness becomes stronger and stronger, resulting in corrosion and perforation of the flue bottom plate and the lower part of the side plate, flue gas leakage, and the need to shut down the furnace for repair, causing great economic losses.

[0005] At present, the flue bottom plate adopts a single material anti-corrosion measure. First, the flue bottom plate directly adopts corrosion-resistant duplex stainless steel; second, the flue bottom plate adopts anti-corrosion glass flakes on a carbon steel substrate; third, the flue bottom plate adopts a polytetrafluoroethylene anti-corrosion plate lined on a carbon steel substrate. These anti-corrosion measures have many defects. Duplex stainless steel has good anti-corrosion performance, but it is expensive, and as time goes by, acid dew accumulates continuously, and duplex stainless steel will also expand from pitting corrosion to large-area corrosion perforation. Glass flakes have good anti-corrosion performance and are cheap, but glass flakes are not wear-resistant and easy to crack; dust particles in the flue gas will wear the anti-corrosion layer, and the alternating hot and cold changes in the flue gas temperature during the low-temperature economizer flushing will cause the glass flakes to crack, thereby further corroding the flue substrate. Polytetrafluoroethylene anti-corrosion plate has excellent anti-corrosion performance, but it is expensive and has extremely high requirements for construction technology. In addition, polytetrafluoroethylene plate has a certain permeability. Corrosive substances in flue gas (hydrochloric acid, hydrofluoric acid) generally penetrate into the interior of the polytetrafluoroethylene plate through welds or weak parts and corrode the substrate.

[0006] How to solve the corrosion problem of the flue bottom plate and the lower part of the side plate behind the low-temperature economizer, extend the service life of the flue bottom plate and the lower part of the side plate, and reduce the time and number of unit shutdowns for maintenance has become an issue that needs to be solved urgently. Summary of the invention

[0007] The invention provides a flue bottom plate anti-corrosion device to solve the problem that the flue bottom plate is easily corroded.

[0008] A technical solution for a flue bottom plate anti-corrosion device is as follows:

[0009] A flue bottom plate anti-corrosion device comprises a flue bottom plate and a flue side plate, the flue bottom plate and the flue side plate are evenly coated with a glass flake anti-corrosion layer, a carbon brick anti-corrosion layer is applied on the glass flake anti-corrosion layer, a spray water pipe is arranged above the carbon brick anti-corrosion layer, and a plurality of nozzles are arranged on the spray water pipe.

[0010] Furthermore, the flue bottom plate and the flue side plates are made of carbon steel or stainless steel, and the flue bottom plate is sloped for drainage.

[0011] Furthermore, the thickness of the glass flake anti-corrosion layer is 2-3.5 mm, and the thickness of the carbon brick anti-corrosion layer is 20-40 mm.

[0012] Furthermore, the spray water pipe is arranged transversely above the carbon brick anti-corrosion layer and perpendicular to the direction of the flue.

[0013] Furthermore, the nozzle is arranged on the spray water pipe obliquely downward along the drainage direction.

[0014] Furthermore, the spray water pipe and the nozzle are both made of duplex stainless steel.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The invention effectively solves the problem of acid liquid adhering to the surface of the flue bottom plate and the lower part of the flue side plate and causing corrosion, improves the anti-corrosion and wear-resistant performance and service life of the flue bottom plate and the flue side plate, and the invention has a simple structure, low cost and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the overall structure of the flue bottom plate anti-corrosion device

[0018] Figure 2 Schematic diagram of embodiment 1 of the flue bottom plate anti-corrosion device

[0019] Figure 3 Schematic diagram of embodiment 2 of the flue bottom plate anti-corrosion device

[0020] 1- flue bottom plate, 2- glass flake anti-corrosion layer, 3- carbon brick anti-corrosion layer, 4- spray water pipe, 5- nozzle, 6- low-temperature economizer, 7- absorption tower, 8- low-temperature economizer inlet, 9- low-temperature economizer outlet, 10- absorption tower slurry pool, 11- low-temperature economizer water collecting hopper. DETAILED DESCRIPTION

[0021] Example 1

[0022] Instructions attached Figure 2 A boiler smoke exhaust system is provided, which includes a low-temperature economizer 6 and an absorption tower 7. A flue bottom plate anti-corrosion device is located in the flue between the low-temperature economizer 6 and the absorption tower 7. The flue bottom plate anti-corrosion device includes a flue bottom plate 1 and a flue side plate. The flue bottom plate 1 is sloped and slopes toward the absorption tower slurry pool 10. A 2-3.5 mm glass flake anti-corrosion layer 2 is evenly applied on the flue bottom plate 1 and the flue side plate. A 20-40 mm carbon brick anti-corrosion layer 3 is evenly applied on the glass flake anti-corrosion layer 2. A spray water pipe 4 is provided on the carbon brick anti-corrosion layer 3. The spray water pipe is horizontally arranged above the carbon brick anti-corrosion layer and perpendicular to the direction of the flue. A plurality of nozzles 5 are arranged on the spray water pipe 4. The nozzles 5 are arranged obliquely downward along the downhill direction of the flue bottom plate 1.

[0023] When the boiler smoke exhaust system is working, the high-temperature flue gas enters the low-temperature economizer 7 from the low-temperature economizer inlet 8 and is converted into low-temperature flue gas and discharged from the low-temperature economizer outlet 9 into the flue. The low-temperature flue gas condenses into acid dew in the flue and falls onto the surface of the carbon brick anti-corrosion layer 3 under the action of gravity. At the same time, the nozzle 5 on the spray water pipe 4 continuously sprays water onto the surface of the carbon brick anti-corrosion layer 3 to form a water film. The water film continuously dilutes the condensed and dripping acid dew and carries the acid dew into the absorption tower slurry pool 10.

[0024] Example 2

[0025] Instructions attached Figure 3 Another embodiment of the flue bottom plate anti-corrosion device is provided. The difference between this embodiment and Example 1 is that the flue bottom plate 1 is set at a certain slope toward the low-temperature economizer water collecting bucket 11, and the nozzle 5 is also set obliquely downward along the downhill direction of the flue bottom plate 1. When the boiler exhaust system is working, the water film formed by the nozzle 5 spraying water on the surface of the carbon brick anti-corrosion layer 3 flows into the low-temperature economizer water collecting bucket 11, and is discharged into the absorption tower slurry pool through the sewage pipe.

[0026] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flue bottom plate anti-corrosion device, comprising a flue bottom plate and a side plate, characterized in that: The flue bottom plate anti-corrosion device is located in the flue between the low-temperature economizer and the absorption tower. The flue bottom plate and the side plate are evenly coated with a glass flake anti-corrosion layer, a carbon brick anti-corrosion layer is applied on the glass flake anti-corrosion layer, a spray water pipe is arranged above the carbon brick anti-corrosion layer, and a plurality of nozzles are arranged on the spray water pipe; The flue bottom plate and the side plates are made of carbon steel or stainless steel, and the flue bottom plate is sloped for drainage; The thickness of the glass flake anti-corrosion layer is 2-3.5 mm, and the thickness of the carbon brick anti-corrosion layer is 20-40 mm; The spray water pipe is arranged horizontally above the carbon brick anti-corrosion layer and perpendicular to the direction of the flue; The nozzle is arranged on the spray water pipe obliquely downward along the drainage direction; After the high-temperature flue gas enters the low-temperature economizer from the inlet, it is converted into low-temperature flue gas and discharged from the outlet of the low-temperature economizer into the flue. The low-temperature flue gas condenses into acid dew in the flue and falls onto the surface of the carbon brick anti-corrosion layer under the action of gravity. At the same time, the nozzle on the spray water pipe continuously sprays water onto the surface of the carbon brick anti-corrosion layer to form a water film. The water film continuously dilutes the condensed and dripping acid dew and carries the acid dew into the absorption tower slurry pool.

2. A flue bottom plate anti-corrosion device according to claim 1, characterized in that: The spray water pipe and the nozzle are both made of duplex stainless steel.

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