Coke oven flue gas graded denitration control system
By setting up a flue gas grading control pipeline in the coke oven flue gas desulfurization and denitrification process, and the coke oven flue gas is processed in a graded manner according to the NOx content, the problem of reduced activity and shortened service life of the catalyst caused by long-term exposure to flue gas is solved, and the effect of extending the service life of the catalyst and reducing production costs is achieved.
Patent Information
- Application Number
- CN202421751442.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-23
- Publication Date
- 2025-05-20
- Estimated Expiration
- 2034-07-23
AI Technical Summary
In the existing coke oven flue gas desulfurization and denitrification process, the denitrification layer catalyst is exposed to the coke oven flue gas for a long time, resulting in a reduction in catalyst activity and shortening service life, which increases production costs.
A coke oven flue gas grading denitrification control system is designed. By setting up a flue gas grading control pipeline in the denitrification device, the denitrition treatment is carried out in a graded manner according to the change in NOx content in the coke oven flue gas to avoid long-term exposure of the catalyst to the flue gas.
It extends the service life of the catalyst, reduces production costs, and improves the efficiency and economicality of denitrification treatment.
Smart Images
Figure CN222887745U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of coke oven flue gas treatment, and particularly relates to a hierarchical denitration control system for coke oven flue gas. Background Art
[0002] Coke oven flue gas is the waste gas generated by the heating and combustion of coke ovens. The main components of coke oven flue gas are pollutants such as sulfur dioxide, nitrogen oxides, particulate matter, and tar. "SDS dry desulfurization + dust removal + low-temperature SCR selective catalytic reduction denitration" is the conventional process for desulfurization and denitration of coke oven flue gas. The coke oven flue gas is first desulfurized with a desulfurizer, then dust is removed, and the desulfurized ash removed by dust removal enters the desulfurized ash bin for collection. The desulfurized and dust-removed coke oven flue gas is denitrified with a reducing agent, and the coke oven flue gas that reaches the emission standard under the action of an induced draft fan is discharged from the coke oven chimney. The type of gas used for coke oven heating determines the change in the composition of coke oven flue gas. For example, when the coke oven is heated with mixed gas and the blending ratio is about 3%, the SO 2 content in the generated coke oven flue gas is about 130 mg / m 3 , and the NO x content is about 100 mg / m 3 ; if one coke oven in a group of coke ovens is heated with coke oven gas instead, the SO 2 content in the generated coke oven flue gas is about 200 mg / m 3 , and the NO x content is about 300 mg / m 3 ; when the coke oven is heated entirely with blast furnace gas, the SO 2 content in the generated coke oven flue gas is about 100 mg / m 3 , and the NO x content is generally lower than 100 mg / m 3 .
[0003] When the coke oven flue gas is purified by the conventional process of "SDS dry desulfurization + dust removal + low-temperature SCR selective catalytic reduction denitration", the catalyst in the denitration layer is always in the environment of high-flow coke oven flue gas, which has an adverse effect on the chemical life of the catalyst. Moreover, the unremoved SO 2 in the coke oven flue gas reacts with the denitrification reducing agent NH 3 to generate ammonium bisulfate and ammonium sulfate, which adhere to the surface of the catalyst, causing the catalyst to lose its activity, affecting the denitrification efficiency, and also reducing the service life of the catalyst. There are sulfur-resistant catalysts on the market. Although they can solve the problem of the reaction between the unremoved SO 2 and the denitrification reducing agent, the price of sulfur-resistant catalysts is higher than that of ordinary catalysts. In large-scale industrial production, the amount of catalysts used is large, increasing the production cost of enterprises. Moreover, sulfur-resistant catalysts cannot solve the problem that the catalyst in the denitrification layer is always in the coke oven flue gas environment, which will shorten the service life of the catalyst. Content of the Utility Model
[0004] In view of the problem that in the existing SDS dry desulfurization + dust removal + low-temperature SCR selective catalytic reduction denitration process flow, the catalyst in the denitration layer is exposed to coke oven flue gas for a long time, affecting the use effect and service life of the catalyst. The utility model provides a hierarchical denitration control system for coke oven flue gas, which meets the enterprise's demand for hierarchical denitration treatment of coke oven flue gas by adding a flue gas hierarchical control pipeline, and reduces the denitration treatment cost of coke oven flue gas.
[0005] The technical solution of the utility model is as follows:
[0006] A hierarchical denitration control system for coke oven flue gas includes a desulfurization pipeline. The outlet of the desulfurization pipeline is communicated with the inlet of a dust removal and denitration integrated device. An air dust removal device and a denitration device are sequentially arranged in the dust removal and denitration integrated device. The air dust removal device includes a plurality of parallel-connected dust removal branches. Each dust removal branch is provided with a dust removal layer. The end of the dust removal layer is provided with an on-line flue gas component analyzer. The denitration device includes a plurality of parallel-connected denitration branches. The outlet of the dust removal branch is communicated with the inlet of the denitration branch. Each denitration branch is sequentially provided with a denitration inlet control valve and a denitration layer. The outlet of the denitration branch is communicated with an induced draft fan. The outlet of the dust removal branch is also communicated with the induced draft fan through a flue gas hierarchical control pipeline. A flue gas hierarchical control pipeline control valve is arranged on the flue gas hierarchical control pipeline.
[0007] The on-line flue gas component analyzer is used to continuously monitor the concentration and emission of gaseous pollutants (including nitrogen oxides, sulfur oxides, and carbon oxides).
[0008] Further, a denitration outlet control valve is arranged at the end of the denitration layer.
[0009] Further, the denitration inlet control valve and the flue gas hierarchical control pipeline control valve are electric sluice valves or pneumatic sluice valves, and the denitration outlet control valve is a pneumatic flap valve or an electric flap valve.
[0010] Further, the denitration inlet control valve and the flue gas hierarchical control pipeline control valve are electric sluice valves, and the denitration outlet control valve is an electric flap valve;
[0011] The hierarchical denitration control system for coke oven flue gas further includes a controller. The on-line flue gas component analyzer is signal-connected to the controller. The controller is respectively control-connected to the denitration inlet control valve, the flue gas hierarchical control pipeline control valve, and the denitration outlet control valve.
[0012] When the controller receives the signal from the on-line flue gas component analyzer, it triggers the control connection to the denitration inlet control valve, the flue gas hierarchical control pipeline control valve, and the denitration outlet control valve.
[0013] Further, the denitration inlet control valve and the flue gas classification control pipeline control valve are pneumatic gate valves, and the denitration outlet control valve is a pneumatic flap valve;
[0014] The coke oven flue gas classification denitration control system further includes a controller. The on-line flue gas composition analyzer is signal-connected to the controller, and the controller is respectively control-connected to the pneumatic actuators of the denitration inlet control valve, the flue gas classification control pipeline control valve, and the denitration outlet control valve.
[0015] When the controller receives the signal from the on-line flue gas composition analyzer, it triggers the air compressor. The air compressor sends compressed air into the pneumatic actuator. After receiving the air, the pneumatic actuator generates pressure and pushes the denitration inlet control valve, the flue gas classification control pipeline control valve, and the denitration outlet control valve to their corresponding positions respectively, controlling the opening and closing of each control valve.
[0016] Further, the outlets of every two dust removal branches are connected to the inlet of the same denitration branch.
[0017] Further, the outlets of each dust removal branch are connected to the inlet of a main outlet pipeline. The outlet of the main outlet pipeline is respectively connected to the inlets of each denitration branch. An on-line flue gas composition analyzer is arranged on the main outlet pipeline, and the outlet of the main outlet pipeline is also connected to the induced draft fan through the flue gas classification control pipeline.
[0018] The beneficial effects of the present utility model are as follows:
[0019] The present utility model provides a coke oven flue gas classification denitration control system. By arranging a flue gas classification control pipeline in the denitration device, the situation that the catalyst in the denitration layer is always in the coke oven flue gas is avoided. When the NO x content in the coke oven flue gas after dust removal is within the emission standard range, no denitration treatment is carried out, and it directly enters the flue gas classification control pipeline and is normally discharged, reducing the time for the catalyst in the denitration layer to be exposed to the environment of the coke oven flue gas; when the NO x content in the coke oven flue gas after dust removal is higher than the emission standard, it first enters the denitration layer for denitration and then is normally discharged. According to the change of the NO x content in the coke oven flue gas, the denitration process is classified, realizing the functions of prolonging the service life of the catalyst and reducing the production cost, and having extremely high practicability and popularization. Description of the Drawings
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.
[0021] Figure 1It is a schematic diagram of the staged denitration control system for coke oven flue gas in Embodiment 1.
[0022] Figure 2 It is a schematic diagram of the staged denitration control system for coke oven flue gas in Embodiment 2.
[0023] In the figure, 1 - dust removal device, 2 - denitration device, 3 - dust removal layer, 4 - on-line flue gas composition analyzer, 5 - denitration inlet control valve, 6 - denitration layer, 7 - induced draft fan, 8 - flue gas staging control pipeline control valve, 9 - denitration outlet control valve. Detailed implementation manners
[0024] In order to enable those skilled in the art to better understand the technical solutions in the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.
[0025] Embodiment 1
[0026] Refer to Figure 1 , a staged denitration control system for coke oven flue gas, comprising a desulfurization pipeline, the outlet of the desulfurization pipeline is communicated with the inlet of an integrated dust removal and denitration device. An integrated dust removal and denitration device is sequentially provided with a dust removal device 1 and a denitration device 2. The dust removal device 1 includes a plurality of parallel-connected dust removal branches. Each dust removal branch is provided with a dust removal layer 3. The end of the dust removal layer 3 is provided with an on-line flue gas composition analyzer 4 (on-line nitrogen oxide analyzer). The denitration device 2 includes a plurality of parallel-connected denitration branches. The outlets of every two dust removal branches are communicated with the inlet of the same denitration branch. Each denitration branch is sequentially provided with a denitration inlet control valve 5 (electric sluice valve) and a denitration layer 6. The end of the denitration layer 6 is provided with a denitration outlet control valve 9 (electric flap valve). The outlet of the denitration branch is communicated with an induced draft fan 7. The outlet of the dust removal branch is also communicated with the induced draft fan 7 through a flue gas staging control pipeline. A flue gas staging control pipeline control valve 8 (electric sluice valve) is provided on the flue gas staging control pipeline. The staged denitration control system for coke oven flue gas further includes a controller. The on-line flue gas composition analyzer 4 is in signal connection with the controller. The controller is respectively in control connection with the denitration inlet control valve 5, the flue gas staging control pipeline control valve 8, and the denitration outlet control valve 9.
[0027] When the coke oven flue gas undergoes SDS dry desulfurization + dust removal + low-temperature SCR selective catalytic reduction denitrification, the coke oven flue gas first enters the desulfurization pipeline for desulfurization, and then enters each dust removal layer 3 respectively. After dust removal, the on-line flue gas component analyzer 4 set at the end of the dust removal layer 3 analyzes the content of each component in the coke oven flue gas. When NO x content is lower than the emission standard (taking 100 mg / m 3 as an example), the denitrification inlet control valve 5 is closed through the controller, and the flue gas grading control valve 8 of the flue gas grading control pipeline is opened. The coke oven flue gas enters the flue gas grading control pipeline, and then is directly discharged from the chimney under the action of the induced draft fan 7; when NO x content is not lower than the emission standard, the denitrification inlet control valve 5 is opened, the flue gas grading control valve 8 of the flue gas grading control pipeline is closed, the denitrification outlet control valve 9 is opened after the coke oven flue gas is denitrified, and then it is discharged from the chimney under the action of the induced draft fan 7.
[0028] In addition, to ensure that the catalyst is always in a hot standby state, the controller can be adjusted to partially open the denitrification inlet control valve 5 and the denitrification outlet control valve 9, and first let a small amount of coke oven flue gas pass through the denitrification layer 6 at a certain flow rate to ensure that the hot standby temperature of the catalyst is higher than 100 °C to prevent the catalyst from getting damp. At this time, the content of NO x , dust, SO 2 , NH 3 in the coke oven flue gas is extremely small, and the impact on the chemical life of the catalyst is extremely slight.
[0029] Example 2
[0030] Refer to Figure 2, A staged denitrification control system for coke oven flue gas, comprising a desulfurization pipeline. The outlet of the desulfurization pipeline is connected to the inlet of an integrated dust removal and denitrification device. Inside the integrated dust removal and denitrification device, a dust removal device 1 and a denitrification device 2 are arranged in sequence. The dust removal device 1 includes a number of parallel dust removal branches, and each dust removal branch is provided with a dust removal layer 3. The denitrification device 2 includes a number of parallel denitrification branches. The outlets of each dust removal branch are connected to the inlet of a main gas outlet path, and the outlet of the main gas outlet path is respectively connected to the inlets of each denitrification branch. The outlet of the denitrification branch is connected to a draft fan 7. The outlet of the main gas outlet path is also connected to the draft fan 7 through a flue gas staged control pipeline. A flue gas component on-line analyzer 4 (on-line nitrogen oxide analyzer) is arranged on the main gas outlet path. Each denitrification branch is sequentially provided with a denitrification inlet control valve 5 (pneumatic slide gate valve) and a denitrification layer 6. The end of the denitrification layer 6 is provided with a denitrification outlet control valve 9 (pneumatic flap valve). A flue gas staged control pipeline control valve 8 (pneumatic slide gate valve) is arranged on the flue gas staged control pipeline. The staged denitrification control system for coke oven flue gas further includes a controller. The flue gas component on-line analyzer 4 is signal-connected to the controller, and the controller is respectively connected to the pneumatic actuators of the denitrification inlet control valve 5, the flue gas staged control pipeline control valve 8, and the denitrification outlet control valve 9 for control.
[0031] When the coke oven flue gas undergoes SDS dry desulfurization + dust removal + low-temperature SCR selective catalytic reduction denitrification, the coke oven flue gas first enters the desulfurization pipeline for desulfurization, and then enters each dust removal layer 3 respectively. After dust removal, the coke oven flue gas is merged into the main gas outlet path. The on-line analyzer 4 analyzes the content of each component in the coke oven flue gas. According to the specific flow rate and NO x content, select to open the denitrification inlet control valve 5 and close all flue gas staged control pipeline control valves 8, or open the flue gas staged control pipeline control valve 8 and close all denitrification inlet control valves 5. Specifically, when the NO x content is lower than the emission standard (taking 100 mg / m 3 as an example), then close all denitrification inlet control valves 5 and open the flue gas staged control pipeline control valve 8 of the flue gas staged control pipeline. The coke oven flue gas enters the flue gas staged control pipeline, and then under the action of the draft fan 7, it is directly discharged from the chimney; when the NO x content is not lower than the emission standard, then open the denitrification inlet control valve 5 and close all flue gas staged control pipeline control valves 8. After the coke oven flue gas is denitrified, open the denitrification outlet control valve 9, and then under the action of the draft fan 7, it is discharged from the chimney.
[0032] In addition, to ensure that the catalyst is always in a hot standby state, the denitrification inlet control valve 5 and the denitrification outlet control valve 9 can be partially opened. First, let a small amount of coke oven flue gas pass through the denitrification layer 6 at a certain flow rate to ensure that the hot standby temperature of the catalyst is higher than 100 °C and prevent the catalyst from getting damp. At this time, the NO in the coke oven flue gas x, dust, SO 2 , NH 3 The content is extremely small and has extremely little impact on the chemical life of the catalyst.
[0033] Although the present utility model has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present utility model is not limited thereto. Without departing from the spirit and essence of the present utility model, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present utility model, and these modifications or substitutions should all be within the scope of the present utility model. / Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, and all should be covered within the protection scope of the present utility model.
Claims
1. A coke oven flue gas graded denitrification control system, comprising a desulfurization pipeline, characterized in that: The outlet of the desulfurization pipeline is connected to the inlet of the integrated dust removal and denitration device. The integrated dust removal and denitration device is provided with a dust removal device (1) and a denitration device (2) in sequence. The dust removal device (1) comprises a plurality of dust removal branches arranged in parallel. Each dust removal branch is provided with a dust removal layer (3). An online flue gas component analyzer (4) is provided at the end of the dust removal layer (3). The denitration device (2) comprises a plurality of denitration branches arranged in parallel. The outlet of the dust removal branch is connected to the inlet of the denitration branch. Each denitration branch is provided with a denitration inlet control valve (5) and a denitration layer (6) in sequence. The outlet of the denitration branch is connected to an induced draft fan (7). The outlet of the dust removal branch is also connected to the induced draft fan (7) via a flue gas classification control pipeline. A flue gas classification control pipeline control valve (8) is provided on the flue gas classification control pipeline.
2. A coke oven flue gas graded denitration control system as claimed in claim 1, characterized in that: A denitration outlet control valve (9) is provided at the end of the denitration layer (6).
3. A coke oven flue gas graded denitration control system as claimed in claim 2, characterized in that: The denitration inlet control valve (5) and the flue gas classification control pipeline control valve (8) are electric gate valves or pneumatic gate valves, and the denitration outlet control valve (9) is a pneumatic flap valve or an electric flap valve.
4. A coke oven flue gas graded denitration control system as claimed in claim 3, characterized in that: The denitration inlet control valve (5) and the flue gas classification control pipeline control valve (8) are electric gate valves, and the denitration outlet control valve (9) is an electric flap valve; The coke oven flue gas classification denitration control system also includes a controller, the flue gas composition online analyzer (4) is connected to the controller signal, and the controller is respectively connected to the denitration inlet control valve (5), the flue gas classification control pipeline control valve (8), and the denitration outlet control valve (9).
5. A coke oven flue gas graded denitration control system as claimed in claim 3, characterized in that: The denitration inlet control valve (5) and the flue gas classification control pipeline control valve (8) are pneumatic gate valves, and the denitration outlet control valve (9) is a pneumatic flap valve; The coke oven flue gas staged denitration control system also includes a controller, a flue gas composition online analyzer (4) is connected to the controller signal, and the controller is respectively connected to the pneumatic actuator control of the denitration inlet control valve (5), the flue gas staged control pipeline control valve (8), and the denitration outlet control valve (9).
6. A coke oven flue gas graded denitration control system as claimed in claim 1, characterized in that: The outlets of every two dust removal branches are connected to the inlet of the same denitrification branch.
7. A coke oven flue gas graded denitration control system as claimed in claim 1, characterized in that: The outlets of the dust removal branches are connected to the inlet of a main gas outlet, and the outlets of the main gas outlet are respectively connected to the inlet of each denitrification branch. An online flue gas composition analyzer (4) is provided on the main gas outlet, and the outlet of the main gas outlet is also connected to an induced draft fan (7) via a flue gas classification control pipeline.