Ultra-low emission system of double-heat-storage heating furnace

Abstract

The utility model belongs to the technical field of industrial heating, and relates to an ultralow emission system of a double-heat-storage heating furnace, which comprises a soot pipeline and an empty smoke pipeline which are connected with the double-heat-storage heating furnace, the soot pipeline is provided with a flow detection device, a residual CO combustion device and a first SCR (Selective Catalytic Reduction) denitration device which are sequentially arranged along the flowing direction of smoke, and the empty smoke pipeline is provided with second SCR denitration devices which are sequentially arranged along the flowing direction of the smoke. According to the ultralow emission system of the double-heat-storage heating furnace, the structures of the soot pipeline and the empty smoke pipeline are optimized, so that the problem that NOx emission of the double-heat-storage heating furnace exceeds the standard and the problem that coal gas is continuously emitted from a combustor front collecting pipe to a reversing valve in the reversing period of a heat storage unit are solved; and in addition, coal gas and air fed into the heating furnace can be preheated, so that the energy-saving effect of the double-heat-storage heating furnace is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of industrial heating and relates to an ultra-low emission system of a double heat storage heating furnace. Background Art

[0002] Steel enterprises are still in the process of technology accumulation and improvement, and are characterized by high energy consumption and high pollution. The processes of steel enterprises are raw materials, coking, ironmaking, steelmaking, continuous casting, rolling (hot rolling / cold rolling), and finished products. The rolling process is the last link in the steel product process, and rolling quality and rolling speed have become important assessment indicators.

[0003] The energy consumption of steel rolling heating furnace accounts for 60%-70% of the energy consumption of steel rolling process. This process is an important breakthrough for energy saving and emission reduction. According to the quality of fuel, steel rolling heating furnace can be divided into conventional heating furnace (high calorific value fuel) or double heat storage heating furnace (low calorific value fuel) as disclosed in the Chinese patent with publication number CN218329352U. The double heat storage heating furnace uses the heat storage unit to preheat the low calorific value gas and combustion air to 1000℃, while reducing the emission temperature of coal smoke and air smoke, realizing the efficient use of low calorific value gas, and playing a role in energy saving and emission reduction.

[0004] However, there are still two problems with the dual heat storage combustion technology: First, the high temperature and low calorific value gas and high temperature combustion air are burned, the flame center temperature is high, and the thermal NO x Rapid production can easily lead to NO in flue gas x The emissions exceeded the standard; secondly, during the reversing process of the heat storage unit, the gas between the burner header and the reversing valve was extracted, and toxic and flammable components such as CO were continuously discharged into the atmosphere. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide an ultra-low emission system for a double heat storage heating furnace to solve the NO x The problem of excessive emissions and the problem of continuous gas emissions from the front header to the reversing valve of the burner in the reversing cycle of the heat storage unit.

[0006] In order to achieve the above object, the utility model provides the following technical solutions:

[0007] An ultra-low emission system for a dual heat storage heating furnace comprises a coal smoke pipeline and an air smoke pipeline connected to the dual heat storage heating furnace, wherein the coal smoke pipeline is provided with a flow detection device, a residual CO combustion device and a first SCR denitrification device arranged in sequence along the flue gas flow direction, and the air smoke pipeline is provided with a second SCR denitrification device arranged in sequence along the flue gas flow direction.

[0008] Furthermore, it also includes a gas pipeline and an air pipeline connected to the dual regenerative heating furnace, the coal smoke pipeline is also provided with a gas preheater located after the first SCR denitration device, and the gas pipeline is connected to the dual regenerative heating furnace through the gas preheater;

[0009] The air smoke pipeline is also provided with an air preheater located after the second SCR denitration device, and the air pipeline is connected to the dual heat storage heating furnace through the air preheater.

[0010] Furthermore, the dual heat storage heating furnace includes a heating furnace, a burner arranged in the heating furnace, a gas box and an air box connected to the burner, and the gas box is connected to the gas pipeline and the coal smoke pipeline through a three-way reversing valve, and the air box is connected to the air smoke pipeline and the air pipeline through a three-way reversing valve.

[0011] Furthermore, the gas preheater and the air preheater are plate preheaters or tube preheaters.

[0012] Furthermore, the residual CO combustion device is also connected to a supplementary combustion gas pipe and a supplementary combustion air pipe, and regulating valves and flow detection devices are provided on the supplementary combustion gas pipe and the supplementary combustion air pipe, and the residual CO combustion device has a supplementary combustion nozzle connected to the supplementary combustion gas and the supplementary combustion air pipe.

[0013] Furthermore, the soot pipeline is also provided with a CO concentration detection device and an O2 concentration detection device located between the residual CO combustion device and the flow detection device, and a temperature detection device located between the residual CO combustion device and the first SCR denitrification device.

[0014] Furthermore, the empty smoke pipeline is also provided with a regulating valve and a temperature detection device arranged before the second SCR denitration device.

[0015] Furthermore, the residual CO combustion device is a porous medium combustion device or a catalytic combustion device.

[0016] The beneficial effects of the utility model are:

[0017] The utility model provides an ultra-low emission system for a double heat storage heating furnace, which solves the problem of NO emission in the double heat storage heating furnace by optimizing the structure of the coal smoke pipeline and the air smoke pipeline. x It can solve the problem of excessive emissions and the problem of continuous gas emissions from the front header of the burner to the reversing valve in the reversing cycle of the heat storage unit; and it can also preheat the gas and air sent to the heating furnace, thereby improving the energy-saving effect of the double heat storage heating furnace.

[0018] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and research, or can be taught from the practice of the present invention to some extent. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be described in detail below in conjunction with the accompanying drawings, in which:

[0020] Figure 1 It is a structural schematic diagram of an ultra-low emission system of a double heat storage heating furnace in the utility model.

[0021] Figure numerals: gas pipeline 1, gas preheater 2, first SCR denitrification device 3, residual CO combustion device 4, soot pipeline 5, three-way reversing valve 6, air smoke pipeline 7, second SCR denitrification device 8, air pipeline 9, air preheater 10, gas box 11, air box 12, regulating valve 13, temperature detection device 14, CO concentration detection device 15, O2 concentration detection device 16, flow detection device 17. DETAILED DESCRIPTION

[0022] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0023] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present utility model. In order to better illustrate the embodiments of the present utility model, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0024] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "back" and the like indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0025] See also Figure 1 , which is an ultra-low emission system of a dual regenerative heating furnace, comprising a gas pipeline 1, a soot pipeline 5, an air pipeline 9 and an air smoke pipeline 7 connected to the dual regenerative heating furnace, the soot pipeline 5 is provided with a flow detection device 17, a residual CO combustion device 4, a first SCR denitration device 3 and a gas preheater 2 arranged in sequence along the flue gas flow direction, and the gas pipeline 1 is connected to the dual regenerative heating furnace through the gas preheater 2, so that the gas in the gas pipeline 1 is supplied to the dual regenerative heating furnace after heat exchange with the high-temperature soot in the soot pipeline 5 through the gas preheater 2;

[0026] The air-smoke pipeline 7 is provided with a second SCR denitrification device 8 and an air preheater 10 arranged in sequence along the flue gas flow direction, and the air pipeline 9 is connected to the dual heat storage heating furnace through the air preheater 10, so that the air in the air pipeline 9 exchanges heat with the high-temperature air and smoke in the air-smoke pipeline 7 through the air preheater 10 and is supplied to the dual heat storage heating furnace.

[0027] Specifically, the dual heat storage heating furnace includes a heating furnace (not shown), a burner (not shown) arranged in the heating furnace, a gas box 11 and an air box 12 connected to the burner, and the gas box 11 is connected to the gas pipeline 1 and the coal smoke pipeline 5 through a three-way reversing valve 6, and the air box 12 is connected to the air smoke pipeline 7 and the air pipeline 9 through a three-way reversing valve 6; the burner connecting the gas box 11 and the air box 12 is usually arranged relative to each other in the heating furnace, and adopts a cross-intermittent operation to facilitate the entry of gas and air in the heating furnace and the discharge of smoke; and the gas pipeline 1, the coal smoke pipeline 5, the air pipeline 9 and the air smoke pipeline 7 are all provided with a fan as a power source. The specific structure of the dual heat storage heating furnace can be referred to the Chinese patent with publication number CN 218329352 U, and the utility model will not be repeated.

[0028] The flue gas generated by the combustion of fuel in the dual heat storage heating furnace is discharged in two ways, one way is discharged through the coal smoke side (gas box 11), and the other way is discharged through the air smoke side (air box 12). In order to meet the optimal operating temperature range of the current SCR denitration technology, the normal emission temperature control range of coal smoke and air smoke during normal production of the dual heat storage heating furnace is 250℃-450℃ (it should be noted that the purpose of this temperature range is to meet the optimal operating temperature range of the current SCR denitration technology. With the development of technology, the lower limit of this temperature range can be adjusted).

[0029] When the double regenerative heating furnace is in normal production, the flue gas composition on the coal smoke side contains NO generated by coal gas combustion. x , and the gas (CO) between the front header of the burner and the three-way reversing valve 6 during the reversing process of the heat storage unit is mixed. The flue gas components on the air-smoke side only contain NO generated by the combustion of coal gas. x .

[0030] Furthermore, the residual CO combustion device 4 is also connected to a supplementary combustion gas pipe and a supplementary combustion air pipe, and a regulating valve 13 and a flow detection device 17 are provided on the supplementary combustion gas pipe and the supplementary combustion air pipe, and the residual CO combustion device 4 is provided with a supplementary combustion nozzle connected to the supplementary combustion gas and the supplementary combustion air pipe; and a CO concentration detection device 15 and an O2 concentration detection device 16 located between the residual CO combustion device 4 and the flow detection device 17, and a temperature detection device 14 located between the residual CO combustion device 4 and the first SCR denitrification device 3 are provided on the soot pipeline 5.

[0031] This embodiment uses the ultra-low emission system of the double heat storage heating furnace, and the NO x Chemical removal is carried out by the first SCR denitrification device 3, and CO on the soot side is burned and removed by the residual CO combustion device 4. The temperature control range of the soot pipeline 5 is 250℃-450℃. When the soot temperature is lower than 250℃, the opening of the regulating valve 13 on the supplementary combustion gas pipeline is increased. When the soot temperature is higher than 250℃, the regulating valve on the supplementary combustion gas pipeline is closed. When the O2 flow converted from the O2 concentration detected on the soot pipeline can meet the CO flow converted from the CO concentration detected on the soot pipeline and the amount of O2 required for complete combustion of the supplementary combustion gas, the regulating valve on the supplementary combustion air pipeline is closed, otherwise the opening of the air regulating valve is increased until the O2 flow meets the demand for complete combustion. When the soot temperature is higher than 450℃, the regulating valve on the supplementary combustion air is opened and increased until the soot temperature drops to 450℃.

[0032] Furthermore, the air smoke pipeline 7 is also provided with a regulating valve 13 and a temperature detection device 14 before the second SCR denitration device 8 is arranged.

[0033] In this embodiment, the ultra-low emission system of the double heat storage heating furnace is used, and the air-to-gas side NO x By using the second SCR denitrification device 8 for chemical removal, the temperature control range of the air smoke pipeline is 250℃-450℃. When the air smoke temperature is lower than 250℃, the opening of the regulating valve 13 on the air smoke pipeline 7 is increased to increase the air smoke flow rate. When the air smoke temperature is higher than 450℃, the opening of the regulating valve 13 on the air smoke pipeline 7 is reduced to reduce the air smoke flow rate.

[0034] Preferably, the gas preheater 2 and the air preheater 10 are plate preheaters or tubular preheaters, and the residual CO combustion device 15 can be a porous medium combustion device or a catalytic combustion device, which is used to burn and remove CO in the flue gas;

[0035] In summary, this embodiment uses the ultra-low emission system of the double heat storage heating furnace, and the NO x , combustible components (including CO, etc.) and NO on the air-smoke side x All of them have been effectively removed, achieving the ultra-low emission target and meeting the national ultra-low emission requirements.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. An ultra-low emission system of a dual heat storage heating furnace, characterized in that: It includes a coal smoke pipeline and an air smoke pipeline connected to the double heat storage heating furnace. The coal smoke pipeline is provided with a flow detection device, a residual CO combustion device and a first SCR denitrification device arranged in sequence along the flue gas flow direction. The air smoke pipeline is provided with a second SCR denitrification device arranged in sequence along the flue gas flow direction.

2. The ultra-low emission system of the dual heat storage heating furnace according to claim 1 is characterized in that: It also includes a gas pipeline and an air pipeline connected to the dual regenerative heating furnace, the coal smoke pipeline is also provided with a gas preheater located after the first SCR denitration device, and the gas pipeline is connected to the dual regenerative heating furnace through the gas preheater; The air smoke pipeline is also provided with an air preheater located after the second SCR denitration device, and the air pipeline is connected to the dual heat storage heating furnace through the air preheater.

3. The ultra-low emission system of the dual heat storage heating furnace according to claim 2 is characterized in that: The dual heat storage heating furnace includes a heating furnace, a burner arranged in the heating furnace, a gas box and an air box connected to the burner, and the gas box is connected to the gas pipeline and the coal smoke pipeline through a three-way reversing valve, and the air box is connected to the air smoke pipeline and the air pipeline through a three-way reversing valve.

4. The ultra-low emission system of the dual heat storage heating furnace according to claim 2 is characterized in that: The gas preheater and the air preheater are plate preheaters or tube preheaters.

5. The ultra-low emission system of the dual heat storage heating furnace according to claim 1 is characterized in that: The residual CO combustion device is also connected to a supplementary combustion gas pipe and a supplementary combustion air pipe, and both the supplementary combustion gas pipe and the supplementary combustion air pipe are provided with regulating valves and flow detection devices, and the residual CO combustion device has a supplementary combustion nozzle connected to the supplementary combustion gas and the supplementary combustion air pipes.

6. The ultra-low emission system of the dual heat storage heating furnace according to claim 5 is characterized in that: The soot pipeline is also provided with a CO concentration detection device and an O2 concentration detection device located between the residual CO combustion device and the flow detection device, and a temperature detection device located between the residual CO combustion device and the first SCR denitration device.

7. The ultra-low emission system of the dual heat storage heating furnace according to claim 1 is characterized in that: The air smoke pipeline is also provided with a regulating valve and a temperature detection device arranged before the second SCR denitration device.

8. The ultra-low emission system of the dual heat storage heating furnace according to claim 1 is characterized in that: The residual CO combustion device is a porous medium combustion device or a catalytic combustion device.

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