Combustion control system and combustion control method for cooperative heating of high-calorific-value coal gas and low-calorific-value coal gas

Abstract

The invention belongs to the field of industrial heating furnaces, and relates to a combustion control system and a combustion control method for cooperative heating of high-calorific-value and low-calorific-value coal gas. The combustion control system comprises multiple types of burners arranged on the heating furnace, and a low-heating-value gas system, a high-heating-value gas system, an air system and an air subsystem which are communicated with the burners. The method comprises the steps that furnace temperature control is conducted, specifically, the flow of each low-heating-value gas pipeline, the flow of each high-heating-value gas pipeline, the flow of each first air pipeline and the flow of each second air pipeline are adjusted so that the difference value between the actual temperature T1 and the set temperature T2 of a temperature control area of the heating furnace can be controlled not to exceed 10 DEG C; and furnace pressure control: adjusting the flow of each low-heat-value soot pipeline, each empty smoke pipeline and each conventional smoke exhaust pipeline so as to control the difference value between the actual pressure P1 and the set pressure P2 of the hearth of the heating furnace not to exceed 5Pa. Dual utilization of fuel of the heating furnace is achieved, and the defects that the gas demand quantity and the gas supply quantity of the heating furnace are not matched, and the economy and rationality of single gas utilization are limited are overcome.

Description

Technical Field

[0001] The invention belongs to the field of industrial heating furnaces and relates to a combustion control system and a combustion control method for coordinated heating of high- and low-calorific value coal gases. Background Art

[0002] Long-process steel enterprises dominate the total domestic steel production capacity, accounting for up to 90% of the production capacity. Compared with short-process steel enterprises, long-process steel enterprises are more equipped with coking and ironmaking processes, which produce by-products such as coke oven gas and blast furnace gas. In the steelmaking process, short-process enterprises mostly use electric furnace technology, while long-process enterprises use converter technology, and the converter process further produces converter gas. Therefore, before the steel rolling process of long-process steel enterprises, there will be a variety of process by-products such as coke oven gas, blast furnace gas and converter gas, which provide a fuel source for the steel rolling heating furnace.

[0003] However, in hot rolling, medium and thick plate, wide and thick plate rolling mills, there are usually multiple heating furnaces, and due to the production capacity of the rolling mill, the supply of a single gas is often unable to meet the gas demand of multiple heating furnaces. This leads to a mismatch between gas supply and demand. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a combustion control system and a combustion control method for coordinated heating of high and low calorific value coal gases, so as to realize the "double utilization" of heating furnace fuel, so as to overcome the mismatch between the gas demand of the heating furnace in the steel rolling workshop and the gas supply of the steel enterprise, as well as the limited economy and rationality of single coal gas utilization.

[0005] In a first aspect, the present invention provides a combustion control system for coordinated heating of high and low calorific value coal gases, the combustion control system comprising a plurality of burners arranged on a heating furnace, and a low calorific value coal gas system, a high calorific value coal gas system, an air system and an air subsystem connected to the burners; wherein:

[0006] A plurality of burners are arranged oppositely on the furnace walls on both sides of the heating furnace; the heating furnace is divided into a heating section, a heating section and a soaking section along the length direction, and each section is provided with at least one pair of burners;

[0007] The low calorific value gas system is used to supply low calorific value fuel to the heating furnace, and comprises a low calorific value gas pipeline connected to each burner located in the first heating stage and the second heating stage;

[0008] The high calorific value gas system is used to supply high calorific value fuel to the heating furnace, and includes a high calorific value gas pipeline connected to each burner located in the soaking section;

[0009] The air system and the air subsystem are used to supply air to the heating furnace, and the two respectively include a first air duct and a second air duct; the first air duct is connected to each burner located in the first heating section and the second heating section, and the second air duct is connected to each burner located in the soaking section;

[0010] According to the fuel types in the low calorific value gas pipeline and the high calorific value gas pipeline, it is determined whether each burner group adopts a double regenerative burner or a conventional burner.

[0011] Optionally, a first burner group, a second burner group and a third burner group are respectively provided on the first heating section, the second heating section and the equalizing section, and each burner group is composed of multiple burners of the same type; the low calorific value gas pipeline and the first air pipeline are connected to each burner in the first burner group and the second burner group, and the high calorific value gas pipeline and the second air pipeline are connected to each burner in the third burner group.

[0012] Optionally, the combustion control system also includes a low calorific value coal smoke system for discharging flue gas generated by the combustion of low calorific value fuel, which includes a low calorific value coal smoke pipe; one end of the low calorific value coal smoke pipe is connected to each burner located in the first heating stage and the second heating stage, and the other end is connected to the low calorific value coal smoke chimney.

[0013] Optionally, the combustion control system also includes an air smoke system, which is used to discharge waste gas or air not involved in combustion, and includes an air smoke duct; one end of the air smoke duct is connected to each burner located in the first heating stage and the second heating stage, and the other end is connected to the air smoke chimney.

[0014] Optionally, the combustion control system also includes a conventional smoke exhaust system for discharging smoke from the heating furnace, which includes a conventional smoke exhaust pipe; one end of the conventional smoke exhaust pipe is connected to a conventional smoke exhaust duct arranged in the furnace walls on both sides of the heating furnace, and the other end is connected to a conventional smoke exhaust chimney.

[0015] Optionally, when the fuel transported by the low calorific value gas pipeline is blast furnace gas and the fuel transported by the high calorific value gas pipeline is one or more of coke oven gas, converter gas, mixed gas, and natural gas, the first burner group and the second burner group use double regenerative burners, and the third burner group uses conventional burners.

[0016] Optionally, when the fuel transported by the low calorific value gas pipeline is one or more of coke oven gas, converter gas, and mixed gas, and the fuel transported by the high calorific value gas pipeline is one or more of natural gas and liquefied petroleum gas, the first burner group, the second burner group, and the third burner group all use conventional burners.

[0017] Optionally, the first burner group and the second burner group each include four double regenerative heat burners, and the double regenerative heat burners include a low calorific value gas heat storage tank and an air heat storage tank; the low calorific value gas pipeline is connected to the low calorific value gas burner front header, and is connected to each low calorific value gas heat storage tank through multiple low calorific value gas burner front branches; the first air pipeline is connected to the air burner front header, and is connected to each air heat storage tank through multiple air burner front branches.

[0018] Optionally, the third burner group includes four conventional burners, each of which has a conventional burner gas interface and a conventional burner air interface. The high calorific value gas pipeline is connected to each conventional burner gas interface through a high calorific value gas burner front header, and the second air pipeline is connected to each conventional burner air interface.

[0019] Optionally, along the fuel flow direction, a low calorific value gas butterfly valve, a low calorific value gas blind plate valve, a low calorific value gas regulating and shut-off valve, a low calorific value gas flow meter, a low calorific value gas section flow meter, a low calorific value gas section regulating and shut-off valve, and a low calorific value gas reversing valve are sequentially arranged on the pipeline connecting the low calorific value gas pipeline and the first burner group or the second burner group;

[0020] Along the fuel flow direction, a high calorific value gas butterfly valve, a high calorific value gas blind plate valve, a high calorific value gas regulating and shut-off valve, a high calorific value gas flow meter, a high calorific value gas section flow meter, and a high calorific value gas section regulating and shut-off valve are sequentially arranged on the pipeline connecting the high calorific value gas pipeline and the third burner group.

[0021] Optionally, along the air flow direction, a combustion-supporting fan, an air flow meter, a first air section flow meter, a first air section regulating shut-off valve, and an air reversing valve are sequentially arranged on the pipeline connecting the first air duct with the first burner group and the second burner group; along the air flow direction, a second air section flow meter, a second air section regulating shut-off valve, a hot air release valve, and an air preheater are sequentially arranged on the pipeline connecting the second air duct with the third burner group.

[0022] Optionally, along the direction of flue gas flow, a low calorific value coal smoke reversing valve, a low calorific value coal smoke regulating and shut-off valve, a low calorific value coal smoke exhaust fan, and a low calorific value coal smoke chimney are sequentially arranged on the low calorific value coal smoke pipeline, and an air smoke reversing valve, an air smoke regulating and shut-off valve, an air smoke exhaust fan, and an air smoke chimney are sequentially arranged on the air smoke pipeline.

[0023] Optionally, the air smoke pipe is connected to the front header of the air burner, and the connectivity between the pipes is switched by an air reversing valve and an air smoke reversing valve; the low calorific value coal smoke pipe is connected to the front header of the low calorific value burner, and the connectivity between the pipes is switched by a low calorific value coal smoke reversing valve and a low calorific value gas reversing valve.

[0024] Optionally, the reversing valves on the burners located on the same side of the furnace wall of the heating furnace are in an interlocking relationship and are opposite to the states of the reversing valves of the burners on the opposite side; the interlocking relationship is: the states of the low calorific value gas reversing valve and the air reversing valve are consistent; the states of the low calorific value coal smoke reversing valve and the air smoke reversing valve are consistent and opposite to the states of the low calorific value gas reversing valve and the air reversing valve.

[0025] In a second aspect, the present invention further provides a combustion control method for high- and low-calorific value coal gas cooperative heating, which is applied to the above-mentioned combustion control system for high- and low-calorific value coal gas cooperative heating, comprising:

[0026] Furnace temperature control: adjust the flow of each low calorific value gas pipeline, high calorific value gas pipeline, first air pipeline and second air pipeline to control the difference between the actual temperature T1 and the set temperature T2 of the temperature control zone of the heating furnace to not exceed 10°C;

[0027] Furnace pressure control: adjust the flow of each low calorific value coal smoke duct, empty smoke duct and conventional smoke exhaust duct to control the difference between the actual pressure P1 and the set pressure P2 of the furnace of the heating furnace to not exceed 5Pa.

[0028] Optionally, when T1≥T2 and T1-T2>10℃, the switching cycle of the low calorific value gas pipeline, the low calorific value coal smoke pipeline, the first air pipeline and the air smoke pipeline remains unchanged, and the flow of the low calorific value gas pipeline, the low calorific value coal smoke pipeline, the first air pipeline and the air smoke pipeline is reduced.

[0029] Optionally, when 10℃≤T2-T1≤30℃, the switching cycle of the low calorific value gas pipeline, the low calorific value coal smoke pipeline, the first air pipeline and the air smoke pipeline remains unchanged, and the flow rates of the low calorific value gas pipeline, the low calorific value coal smoke pipeline, the first air pipeline and the air smoke pipeline are increased.

[0030] Optionally, when T2-T1>30℃, the reversing period of the low calorific value gas pipeline, the low calorific value coal smoke pipeline, the first air pipeline and the air smoke pipeline is extended so that the temperature of the low calorific value gas pipeline and the first air pipeline at the burner inlet is ≤180℃; the flow rate of the low calorific value gas pipeline, the low calorific value coal smoke pipeline, the first air pipeline and the air smoke pipeline is increased.

[0031] Optionally, when P1≥P2, increase the flow rate of the low calorific value coal smoke duct and the air smoke duct, and / or increase the flow rate of the conventional smoke exhaust duct; at the same time, ensure that the temperature of the low calorific value coal gas duct and the first air duct at the burner inlet is ≤180°C.

[0032] Optionally, when P1≤P2, the flow rates of the low calorific value coal smoke duct and the air smoke duct are reduced, and / or the flow rate of the conventional smoke exhaust duct is reduced, while ensuring that the temperature of the low calorific value coal gas duct and the first air duct at the burner inlet is ≤180°C.

[0033] Optionally, during furnace pressure control,

[0034] If the temperature of the low calorific value coal gas pipeline and the first air pipeline at the burner inlet is ≤180°C, the furnace pressure is adjusted by adjusting the flow of the low calorific value coal smoke pipeline and the air smoke pipeline;

[0035] If the temperature of the low calorific value gas pipeline and the first air pipeline at the burner inlet is greater than 180°C, the furnace pressure is adjusted by adjusting the flow rate of the conventional smoke exhaust pipeline;

[0036] If the temperature of the low calorific value gas pipeline and the first air pipeline at the burner inlet is ≤180℃, and only adjusting the flow of the low calorific value coal smoke pipeline and the air smoke pipeline cannot make the furnace pressure meet the standard, then adjust the flow of the conventional smoke exhaust pipeline at the same time to make the furnace pressure meet the standard.

[0037] The beneficial effects of the present invention are:

[0038] First of all, the present invention takes into account the actual conditions such as the differences in production capacity of different steel rolling mills, the different gas demands of heating furnaces, and the different gas supplies of steel enterprises, and proposes a combustion control system and a combustion control method for coordinated heating of high and low calorific value gases. This not only realizes the "double utilization" of heating furnace fuel and effectively meets the energy balance needs of steel enterprises, but also overcomes the defects of the prior art in that gas supply and demand do not match, and the economy and rationality of single gas utilization is limited, thereby improving the flexibility and efficiency of energy utilization.

[0039] Secondly, the invention successfully solves the problem of matching the normal working gas demand of the heating furnace in the steel rolling workshop with the gas supply of the steel enterprise, ensuring the continuous and stable production of the heating furnace. By coordinating the furnace temperature and furnace pressure control methods, the invention further achieves the production goal of "high quality, high efficiency, and low consumption" of the heating furnace, and improves the overall production efficiency of the steel enterprise. Especially for the blast furnace gas with low calorific value, it realizes more economical and reasonable fuel utilization, and effectively promotes the technical exploration and innovation of steel enterprises in the utilization of heating furnace fuel.

[0040] Finally, the combustion control method provided by the present invention can achieve precise control of the furnace temperature and furnace pressure. According to the actual difference, the reverse temperature difference control method, the positive narrow temperature difference control method or the positive wide temperature difference control method is automatically adopted, so that the furnace temperature control accuracy reaches T1-T2≤±10℃. According to the actual difference, the reverse or positive pressure difference control method is automatically adopted so that the furnace pressure control accuracy reaches P1-P2≤±5Pa, which effectively ensures the stable operation of the heating furnace and further improves the quality and production efficiency of steel products.

[0041] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0043] Figure 1 One of the structural schematic diagrams of a combustion control system for cooperative heating of high and low calorific value coal gases provided by the present invention;

[0044] Figure 2 The second structural schematic diagram of a combustion control system for cooperative heating of high and low calorific value coal gases provided by the present invention;

[0045] Figure 3 The third structural schematic diagram of a combustion control system for coordinated heating of high and low calorific value coal gases provided by the present invention.

[0046] Reference numerals:

[0047] 1- low calorific value gas system, 1.1- low calorific value gas pipeline, 1.2- low calorific value gas butterfly valve, 1.3- low calorific value gas blind plate valve, 1.4- low calorific value gas regulating cut-off valve, 1.5- low calorific value gas flowmeter, 1.6- low calorific value gas section flowmeter, 1.7- low calorific value gas section regulating cut-off valve, 1.8- low calorific value gas reversing valve, 1.9- low calorific value gas burner front header, 1.10- low calorific value gas burner front branch pipe, 1.11- low calorific value gas burner front regulating valve, 1.12- low calorific value gas heat storage tank;

[0048] 2- low calorific value coal smoke system, 2.1- low calorific value coal smoke chimney, 2.2- low calorific value coal smoke pipeline, 2.3- low calorific value coal smoke exhaust fan, 2.4- low calorific value coal smoke regulating cut-off valve, 2.5- low calorific value coal smoke reversing valve;

[0049] 3- air system, 3.1- combustion-supporting fan, 3.2- fan outlet cut-off valve, 3.3- fan outlet flexible connection, 3.4- first air pipeline, 3.5- air flow meter, 3.6- first air section flow meter, 3.7- first air section regulating cut-off valve, 3.8- air reversing valve, 3.9- air burner front header, 3.10- air burner front branch pipe, 3.11- air burner front regulating valve, 3.12- air heat storage tank;

[0050] 4-air-smoke system, 4.1-air-smoke chimney, 4.2-air-smoke duct, 4.3-air-smoke exhaust fan, 4.4-air-smoke regulating shut-off valve, 4.5-air-smoke reversing valve;

[0051] 5-high calorific value gas system, 5.1-high calorific value gas pipeline, 5.2-high calorific value gas butterfly valve, 5.3-high calorific value gas blind plate valve, 5.4-high calorific value gas regulating cut-off valve, 5.5-high calorific value gas flowmeter, 5.6-high calorific value gas section flowmeter, 5.7-high calorific value gas section regulating cut-off valve, 5.8-high calorific value gas burner front header, 5.9-conventional burner gas interface;

[0052] 6-air subsystem, 6.1-second air section flow meter, 6.2-second air section regulating cut-off valve, 6.3-second air pipeline, 6.4-conventional burner air interface, 6.5-hot air release valve, 6.6-air preheater;

[0053] 7- Conventional smoke exhaust system, 7.1- Conventional smoke exhaust chimney, 7.2- Conventional smoke exhaust duct, 7.3- Conventional smoke exhaust flue;

[0054] 8-heating furnace; 8.1-first burner group; 8.2-second burner group; 8.3-third burner group. DETAILED DESCRIPTION

[0055] The following describes the embodiments of the present invention by specific examples, and 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 embodiments, 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, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0056] 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", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is 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 orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0057] 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 invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0058] In order to overcome the mismatch between the gas demand of the heating furnace in a steel rolling workshop and the gas supply of the steel enterprise, as well as the limited economy and rationality of single gas utilization, the present invention provides a combustion control system and a combustion control method for coordinated heating of high and low calorific value gases.

[0059] like Figure 1 to Figure 3 The combustion control system includes a plurality of burners arranged on a heating furnace 8, and a low calorific value gas system 1, a high calorific value gas system 5, an air system 3, an air subsystem 6, a low calorific value coal smoke system 2, an air smoke system 4 and a conventional smoke exhaust system 7 connected to the burners.

[0060] Multiple burners are arranged in pairs on the furnace walls on both sides of the heating furnace 8 to directly supply heat to the furnace of the heating furnace 8. The heating furnace 8 is divided into a heating section, a heating section and a soaking section along the length direction. Each section is provided with at least one burner group, and each burner group is composed of multiple burners of the same type. In particular, the burner types of different burner groups may be different, and the burner is selected as a double regenerative burner or a conventional burner according to the fuel type.

[0061] In this embodiment, the first burner group 8.1, the second burner group 8.2 and the third burner group 8.3 are respectively arranged on the first heating section, the second heating section and the soaking section of the heating furnace 8. The furnace top and the furnace bottom of the heating furnace 8 are both made of steel structure, and the surroundings are opposite side wall steel structure and end wall steel structure, and the furnace body is built with refractory masonry.

[0062] The low calorific value gas system 1 is used to supply low calorific value fuel to the heating furnace 8, and includes a low calorific value gas pipeline 1.1, which is connected to each burner located in the first heating section and the second heating section. In this embodiment, the low calorific value gas pipeline 1.1 is connected to each burner in the first burner group 8.1 and the second burner group 8.2. Further, along the fuel flow direction, the pipeline connecting the low calorific value gas pipeline 1.1 to the first burner group 8.1 or the second burner group 8.2 is sequentially provided with a low calorific value gas butterfly valve 1.2, a low calorific value gas blind plate valve 1.3, a low calorific value gas regulating cut-off valve 1.4, a low calorific value gas flowmeter 1.5, a low calorific value gas section flowmeter 1.6, a low calorific value gas section regulating cut-off valve 1.7, and a low calorific value gas reversing valve 1.8. The low calorific value gas butterfly valve 1.2 and the low calorific value gas blind plate valve 1.3 are used to effectively cut off the supply of low calorific value gas, the low calorific value gas regulating cut-off valve 1.4 and the low calorific value gas flow meter 1.5 are used for low calorific value gas flow metering and regulation, and the low calorific value gas section regulating cut-off valve 1.7 is used for regulating the combustion section gas.

[0063] The high calorific value gas system 5 is used to supply high calorific value fuel to the heating furnace 8, and includes a high calorific value gas pipeline 5.1, which is connected to each burner located in the soaking section. In this embodiment, the high calorific value gas pipeline 5.1 is connected to each burner in the third burner group 8.3. Further, along the fuel flow direction, the pipeline connecting the high calorific value gas pipeline 5.1 and the third burner group 8.3 is sequentially provided with a high calorific value gas butterfly valve 5.2, a high calorific value gas blind plate valve 5.3, a high calorific value gas regulating and shutting off valve 5.4, a high calorific value gas flowmeter 5.5, a high calorific value gas section flowmeter 5.6, and a high calorific value gas section regulating and shutting off valve 5.7. The high calorific value gas butterfly valve 5.2 and the high calorific value gas blind plate valve 5.3 are used to effectively cut off the high calorific value gas, the high calorific value gas regulating cut-off valve 5.4 and the high calorific value gas flowmeter 5.5 are used to measure and adjust the high calorific value gas flow, and the high calorific value gas section regulating cut-off valve 5.7 is used to adjust the combustion section gas.

[0064] The air system 3 is used to supply air to the heating furnace 8, and includes a first air duct 3.4, which is connected to each burner located in the first heating section and the second heating section. In this embodiment, the first air duct 3.4 is connected to each burner in the first burner group 8.1 and the second burner group 8.2. Along the air flow direction, the pipeline connecting the first air duct 3.4 and the first burner group 8.1 and the second burner group 8.2 is sequentially provided with a combustion-supporting fan 3.1, a fan outlet shut-off valve 3.2, a fan outlet soft connection 3.3, an air flow meter 3.5, a first air section flow meter 3.6, a first air section regulating shut-off valve 3.7, and an air reversing valve 3.8.

[0065] The air subsystem 6 is used to supply air to the heating furnace 8, and includes a second air duct 6.3, which is connected to each burner located in the soaking section. In this embodiment, the second air duct 6.3 is connected to each third burner group 8.3. Along the air flow direction, the second air section flow meter 6.1, the second air section regulating cut-off valve 6.2, the hot air release valve 6.5, and the air preheater 6.6 are sequentially arranged on the pipeline connecting the second air duct 6.3 and the third burner group 8.3.

[0066] The low calorific value soot system 2 is used to discharge the flue gas generated by the combustion of low calorific value fuel, and includes a low calorific value soot pipe 2.2. One end of the low calorific value soot pipe 2.2 is connected to each burner located in the first heating stage and the second heating stage, and the other end is connected to the low calorific value soot chimney 2.1. Along the flow direction of the flue gas, the low calorific value soot pipe 2.2 is sequentially provided with a low calorific value soot reversing valve 2.5, a low calorific value soot regulating and shut-off valve 2.4, a low calorific value soot exhaust fan 2.3, and a low calorific value soot chimney 2.1.

[0067] The air smoke system 4 is used to discharge waste gas or air not involved in combustion, and includes an air smoke duct 4.2; one end of the air smoke duct 4.2 is connected to each burner located in the first heating stage and the second heating stage, and the other end is connected to the air smoke chimney 4.1. Along the flow direction of the smoke, the air smoke duct 4.2 is provided with an air smoke reversing valve 4.5, an air smoke regulating shut-off valve 4.4, an air smoke exhaust fan 4.3, and an air smoke chimney 4.1 in sequence.

[0068] The conventional smoke exhaust system 7 is used to discharge the smoke in the heating furnace 8, which includes a conventional smoke exhaust pipe 7.2; one end of the conventional smoke exhaust pipe 7.2 is connected to a conventional smoke exhaust duct 7.3 arranged in the furnace walls on both sides of the heating furnace 8, and the other end is connected to a conventional smoke exhaust chimney 7.1.

[0069] It should be noted that in the present invention, low calorific value fuel and high calorific value fuel are relative concepts, and it is only necessary to ensure that the calorific value of the fuel transported in the low calorific value gas pipeline 1.1 is lower than the calorific value of the fuel transported in the high calorific value gas pipeline 5.1. When the fuel transported by the low calorific value gas pipeline 1.1 is blast furnace gas, and the fuel transported by the high calorific value gas pipeline 5.1 is one or more of coke oven gas, converter gas, mixed gas, and natural gas, the first burner group 8.1 and the second burner group 8.2 use double regenerative burners, and the third burner group 8.3 uses conventional burners. When the fuel transported by the low calorific value gas pipeline 1.1 is one or more of coke oven gas, converter gas, and mixed gas, and the fuel transported by the high calorific value gas pipeline 5.1 is one or more of natural gas and liquefied petroleum gas, the first burner group 8.1, the second burner group 8.2, and the third burner group 8.3 all use conventional burners.

[0070] In this embodiment, the fuel transported by the low calorific value gas pipeline 1.1 is blast furnace gas, and the fuel transported by the high calorific value gas pipeline 5.1 is one or more of coke oven gas, converter gas, mixed gas, and natural gas. The first burner group 8.1 and the second burner group 8.2 use double regenerative burners, and the third burner group 8.3 uses conventional burners. The first burner group 8.1 and the second burner group 8.2 each include four double regenerative burners, and the third burner group 8.3 includes four conventional burners.

[0071] In this example, the double regenerative burner includes a pair of low calorific value coal gas heat storage tanks 1.12 and air heat storage tanks 3.12. The low calorific value coal gas pipeline 1.1 is connected to the low calorific value coal gas burner front header 1.9, and is connected to each low calorific value coal gas heat storage tank 1.12 through a plurality of low calorific value coal gas burner front branch pipes 1.10. Each low calorific value coal gas burner front branch pipe 1.10 is provided with a low calorific value coal gas burner front regulating valve 1.11. The first air pipeline 3.4 is connected to the air burner front header 3.9, and is connected to each air heat storage tank 3.12 through a plurality of air burner front branch pipes 3.10. Each air burner front branch pipe 3.10 is provided with an air burner front regulating valve 3.11.

[0072] Furthermore, the air-smoke duct 4.2 is connected to the air burner front header 3.9, which is shared with the first air duct 3.4 to input air into the first burner group 8.1 or the second burner group 8.2 or to output smoke. The connection relationship between the ducts is switched by the air reversing valve 3.8 and the air-smoke reversing valve 4.5. If the air reversing valve 3.8 is in the "open" state, the air-smoke reversing valve 4.5 is in the "closed" state; if the air reversing valve 3.8 is in the "closed" state, the air-smoke reversing valve 4.5 is in the "open" state.

[0073] Furthermore, the low calorific value soot pipeline 2.2 is connected to the low calorific value burner front header 1.9, which shares the low calorific value burner front header 1.9 with the low calorific value gas pipeline 1.1 to introduce fuel into the first burner group 8.1 or the second burner group 8.2 or to discharge flue gas. The connectivity between the pipelines is switched by the low calorific value soot reversing valve 2.5 and the low calorific value gas reversing valve 1.8. The low calorific value gas reversing valve 1.8 is in the "open" state, and the low calorific value soot reversing valve 2.5 is in the "closed" state; if the low calorific value gas reversing valve 1.8 is in the "closed" state, the low calorific value soot reversing valve 2.5 is in the "open" state.

[0074] The conventional burner has a conventional burner gas interface 5.9 and a conventional burner air interface 6.4. The high calorific value gas pipeline 5.1 is connected to each conventional burner gas interface 5.9 through a high calorific value gas burner front header 5.8. The second air pipeline 6.3 is connected to each conventional burner air interface 6.4.

[0075] In particular, the reversing valves on the burners located on the same side of the furnace wall of the heating furnace 8 are in an interlocking relationship and are in opposite states to the reversing valves of the burners on the opposite sides. The interlocking relationship is: the states of the low calorific value gas reversing valve 1.8 and the air reversing valve 3.8 are consistent, and the states of the low calorific value coal smoke reversing valve 2.5 and the air smoke reversing valve 4.5 are consistent and are opposite to the states of the low calorific value gas reversing valve 1.8 and the air reversing valve 3.8. Specifically, if the low calorific value gas reversing valve 1.8 is in the "open" state, the air reversing valve 3.8 is in the "open" state, the low calorific value coal smoke reversing valve 2.5 is in the "closed" state, and the air-smoke reversing valve 4.5 is in the "closed" state; at the same time, if the low calorific value gas reversing valve 1.8 on the opposite side of the heating furnace 8 is in the "closed" state, the air reversing valve 3.8 is in the "closed" state, the low calorific value coal smoke reversing valve 2.5 is in the "open" state, and the air-smoke reversing valve 4.5 is in the "open" state.

[0076] It should be noted that the low calorific value gas regulating and shutoff valve 1.4 plays a role of regulating and shutting off, and can be split into two valves in actual production, one for regulating and shutting off. The high calorific value gas regulating and shutoff valve 5.4 plays a role of regulating and shutting off, and can be split into two valves in actual production, one for regulating and shutting off.

[0077] In some optional embodiments, the air system 3 may use a single or multiple combustion-supporting fans 3.1, and the flow rate of the conventional smoke exhaust duct 7.3 may be adjusted by a combination of a flue damper, a variable frequency fan or a fixed frequency fan and a regulating valve. The chimneys in various systems may use steel chimneys, concrete chimneys, etc., such as low calorific value coal smoke chimney 2.1, air smoke chimney 4.1, etc.

[0078] The present invention also provides a combustion control method for coordinated heating of high and low calorific value coal gases, which is applied to the above-mentioned combustion control system for coordinated heating of high and low calorific value coal gases. The combustion control method includes a furnace temperature control method and a furnace pressure control method.

[0079] The furnace temperature control method uses the difference △T and the difference change rate between the actual temperature T1 of the temperature control zone of the heating furnace 8 and the set temperature T2 of the temperature control zone as signals, and controls the opening of the low calorific value gas section regulating cut-off valve 1.7 and the first air section regulating cut-off valve 3.7 in real time, and adjusts the flow of each low calorific value gas pipeline 1.1, high calorific value gas pipeline 5.1, first air pipeline 3.4 and second air pipeline 6.3 to control △T not to exceed 10°C.

[0080] The furnace pressure control method uses the difference △P and the difference change rate between the actual furnace pressure P1 and the furnace set pressure P2 of the heating furnace 8 as signals, and controls the power of the low calorific value coal smoke exhaust fan 2.3, the air smoke exhaust fan 4.3, and the conventional smoke exhaust fan (or the flue gate on the conventional smoke exhaust duct 7.3) in real time, and adjusts the flow of each low calorific value coal smoke pipe 2.2, the air smoke pipe 4.2 and the conventional smoke exhaust pipe 7.2 to control △P not to exceed 5Pa.

[0081] Specifically, the furnace temperature control method includes the following modes:

[0082] (1) Reverse temperature difference control mode:

[0083] When T1≥T2 and T1-T2>10℃, the switching cycle of the low calorific value gas pipeline 1.1, the low calorific value coal smoke pipeline 2.2, the first air pipeline 3.4 and the air smoke pipeline 4.2 remains unchanged (i.e., the switching cycle of the low calorific value gas reversing valve 1.8, the low calorific value coal smoke reversing valve 2.5, the air reversing valve 3.8 and the air smoke reversing valve 4.5 remains unchanged), and the flow of the low calorific value gas pipeline 1.1, the low calorific value coal smoke pipeline 2.2, the first air pipeline 3.4 and the air smoke pipeline 4.2 is reduced (i.e., the opening of the low calorific value gas section regulating cut-off valve 1.7, the first air section regulating cut-off valve 3.7, the low calorific value coal smoke regulating cut-off valve 2.4 and the air smoke regulating cut-off valve 4.4 is reduced). At the same time, in order to maintain the furnace pressure, the low calorific value coal smoke exhaust fan 2.3 and the air smoke exhaust fan 4.3 follow the change to stabilize the furnace pressure.

[0084] (2) Forward narrow temperature difference control mode:

[0085] When 10℃≤T2-T1≤30℃, the switching cycle of the low calorific value gas pipeline 1.1, the low calorific value coal smoke pipeline 2.2, the first air pipeline 3.4 and the air smoke pipeline 4.2 remains unchanged (i.e., the switching cycle of the low calorific value gas reversing valve 1.8, the low calorific value coal smoke reversing valve 2.5, the air reversing valve 3.8 and the air smoke reversing valve 4.5 remains unchanged), and the flow of the low calorific value gas pipeline 1.1, the low calorific value coal smoke pipeline 2.2, the first air pipeline 3.4 and the air smoke pipeline 4.2 is increased (i.e., the opening of the low calorific value gas section regulating cut-off valve 1.7, the first air section regulating cut-off valve 3.7, the low calorific value coal smoke regulating cut-off valve 2.4 and the air smoke regulating cut-off valve 4.4 is increased). At the same time, in order to maintain the furnace pressure, the low calorific value coal smoke exhaust fan 2.3 and the air smoke exhaust fan 4.3 follow the changes to stabilize the furnace pressure.

[0086] (3) Positive wide temperature difference control mode:

[0087] When T2-T1>30℃, the switching period of the low calorific value gas pipeline 1.1, the low calorific value coal smoke pipeline 2.2, the first air pipeline 3.4 and the air smoke pipeline 4.2 is extended (i.e., the switching period of the low calorific value gas reversing valve 1.8, the low calorific value coal smoke reversing valve 2.5, the air reversing valve 3.8 and the air smoke reversing valve 4.5 is extended) so that the temperature of the low calorific value gas pipeline 1.1 and the first air pipeline 3.4 at the burner inlet is ≤180℃; the flow rate of the low calorific value gas pipeline 1.1, the low calorific value coal smoke pipeline 2.2, the first air pipeline 3.4 and the air smoke pipeline 4.2 is increased (i.e., the opening of the low calorific value gas section regulating and shutting valve 1.7, the first air section regulating and shutting valve 3.7, the low calorific value coal smoke regulating and shutting valve 2.4 and the air smoke regulating and shutting valve 4.4 is increased). At the same time, in order to maintain the furnace pressure, the low calorific value coal smoke exhaust fan 2.3 and the air smoke exhaust fan 4.3 change accordingly.

[0088] Specifically, the furnace pressure control method includes the following modes:

[0089] (1) Reverse pressure difference control mode:

[0090] When P1≥P2, increase the flow rate of the low calorific value coal smoke pipeline 2.2 and the air smoke pipeline 4.2 (i.e. increase the power of the low calorific value coal smoke exhaust fan 2.3 and the air smoke exhaust fan 4.3 in the air smoke exhaust system), and / or increase the flow rate of the conventional smoke exhaust pipeline 7.2 (i.e. increase the power of the conventional smoke exhaust fan or increase the flue damper opening of the conventional smoke exhaust flue 7.3); at the same time, ensure that the temperature of the low calorific value coal gas pipeline 1.1 and the first air pipeline 3.4 at the burner inlet is ≤180℃ (this is the maximum temperature to ensure the normal operation of the equipment).

[0091] (2) Forward pressure difference control mode:

[0092] When P1≤P2, reduce the flow of the low calorific value coal smoke pipeline 2.2 and the air smoke pipeline 4.2 (i.e. reduce the power of the low calorific value coal smoke exhaust fan 2.3 and the air smoke exhaust fan 4.3 in the air smoke exhaust system), and / or reduce the flow of the conventional smoke exhaust pipeline 7.2 (i.e. reduce the power of the conventional smoke exhaust fan or reduce the flue damper opening of the conventional smoke exhaust flue 7.3), while ensuring that the temperature of the low calorific value coal gas pipeline 1.1 and the first air pipeline 3.4 at the burner inlet is ≤180°C.

[0093] In particular, in the process of furnace pressure control, the main means of regulation is to "regulate the flow of low calorific value coal smoke pipe 2.2 and empty smoke pipe 4.2" to maximize the recovery of flue gas heat. The secondary means of regulation is to "regulate the flow of conventional smoke exhaust pipe 7.2" to effectively protect the electrical equipment and instrument detection equipment on the front branch pipes of each burner. Specifically, if the temperature of the low calorific value gas pipeline 1.1 and the first air pipeline 3.4 at the burner inlet is ≤180°C, the furnace pressure is adjusted by adjusting the flow rates of the low calorific value coal smoke pipeline 2.2 and the air smoke pipeline 4.2; if the temperature of the low calorific value gas pipeline 1.1 and the first air pipeline 3.4 at the burner inlet is greater than 180°C, the furnace pressure is adjusted by adjusting the flow rate of the conventional smoke exhaust pipeline 7.2; if the temperature of the low calorific value gas pipeline 1.1 and the first air pipeline 3.4 at the burner inlet is ≤180°C, and only adjusting the flow rates of the low calorific value coal smoke pipeline 2.2 and the air smoke pipeline 4.2 cannot make the furnace pressure meet the standard, then the flow rate of the conventional smoke exhaust pipeline 7.2 is adjusted at the same time to make the furnace pressure meet the standard.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention 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 present invention.

Claims

1. A combustion control system for cooperative heating of high and low calorific value coal gases, characterized in that: The combustion control system comprises a plurality of burners arranged on a heating furnace (8), and a low calorific value gas system (1), a high calorific value gas system (5), an air system (3) and an air subsystem (6) connected to the burners; wherein: A plurality of burners are arranged oppositely on the furnace walls on both sides of the heating furnace (8); the heating furnace (8) is divided into a heating section, a heating section and a soaking section along the length direction, and each section is provided with at least one pair of burners; The low calorific value coal gas system (1) is used to supply low calorific value fuel to the heating furnace (8), and comprises a low calorific value coal gas pipeline (1.1), wherein the low calorific value coal gas pipeline (1.1) is connected to each burner located in the first heating stage and the second heating stage; The high calorific value coal gas system (5) is used to supply high calorific value fuel to the heating furnace (8), and comprises a high calorific value coal gas pipeline (5.1), wherein the high calorific value coal gas pipeline (5.1) is connected to each burner located in the soaking section; The air system (3) and the air subsystem (6) are used to supply air to the heating furnace (8), and the two respectively include a first air pipeline (3.4) and a second air pipeline (6.3); the first air pipeline (3.4) is connected to each burner located in the first heating section and the second heating section, and the second air pipeline (6.3) is connected to each burner located in the soaking section; wherein, According to the fuel types in the low calorific value gas pipeline (1.1) and the high calorific value gas pipeline (5.1), it is determined whether each burner group adopts a double regenerative burner or a conventional burner.

2. The combustion control system according to claim 1, characterized in that: The first heating section, the second heating section and the soaking section are respectively provided with a first burner group (8.1), a second burner group (8.2) and a third burner group (8.3), and each burner group is composed of a plurality of burners of the same type; The low calorific value gas pipeline (1.1) and the first air pipeline (3.4) are connected to each burner in the first burner group (8.1) and the second burner group (8.2), and the high calorific value gas pipeline (5.1) and the second air pipeline (6.3) are connected to each burner in the third burner group (8.3).

3. The combustion control system according to claim 1, characterized in that: It also includes a low calorific value coal smoke system (2) for discharging smoke generated by the combustion of low calorific value fuel, which includes a low calorific value coal smoke pipeline (2.2); one end of the low calorific value coal smoke pipeline (2.2) is connected to each burner located in the first heating stage and the second heating stage, and the other end is connected to the low calorific value coal smoke chimney (2.1).

4. The combustion control system according to claim 3, characterized in that: It also includes an air smoke system (4), which is used to discharge waste gas or air not involved in combustion, and includes an air smoke duct (4.2); one end of the air smoke duct (4.2) is connected to each burner located in the first heating stage and the second heating stage, and the other end is connected to the air smoke chimney (4.1).

5. The combustion control system according to claim 1, characterized in that: It also includes a conventional smoke exhaust system (7) for exhausting smoke from the heating furnace (8), which includes a conventional smoke exhaust pipe (7.2); one end of the conventional smoke exhaust pipe (7.2) is connected to a conventional smoke exhaust duct (7.3) arranged in the furnace walls on both sides of the heating furnace (8), and the other end is connected to a conventional smoke exhaust chimney (7.1).

6. The combustion control system according to claim 2, characterized in that: When the fuel transported by the low calorific value gas pipeline (1.1) is blast furnace gas, and the fuel transported by the high calorific value gas pipeline (5.1) is one or more of coke oven gas, converter gas, mixed gas, and natural gas, the first burner group (8.1) and the second burner group (8.2) use double regenerative burners, and the third burner group (8.3) uses conventional burners.

7. The combustion control system according to claim 2, characterized in that: When the fuel transported by the low calorific value gas pipeline (1.1) is one or more of coke oven gas, converter gas, and mixed gas, and the fuel transported by the high calorific value gas pipeline (5.1) is one or more of natural gas and liquefied petroleum gas, the first burner group (8.1), the second burner group (8.2), and the third burner group (8.3) all use conventional burners.

8. The combustion control system according to claim 6, characterized in that: The first burner group (8.1) and the second burner group (8.2) each include four double regenerative burners, and the double regenerative burners include a low calorific value coal gas regenerative tank (1.12) and an air regenerative tank (3.12); The low calorific value coal gas pipeline (1.1) is connected to the low calorific value coal gas burner front header (1.9), and is connected to each of the low calorific value coal gas heat storage tanks (1.12) through a plurality of low calorific value coal gas burner front branch pipes (1.10); The first air pipeline (3.4) is connected to the air burner front header (3.9), and is connected to each of the air heat storage boxes (3.12) through a plurality of air burner front branch pipes (3.10).

9. The combustion control system according to claim 6 or 7, characterized in that: The third burner group comprises four conventional burners, each of which has a conventional burner gas interface (5.9) and a conventional burner air interface (6.4); The high calorific value gas pipeline (5.1) is connected to each of the conventional burner gas interfaces (5.9) through a high calorific value gas burner front header (5.8), and the second air pipeline (6.3) is connected to each of the conventional burner air interfaces (6.4).

10. The combustion control system according to claim 8, characterized in that: Along the fuel flow direction, a pipeline connecting the low calorific value gas pipeline (1.1) and the first burner group (8.1) or the second burner group (8.2) is provided with a low calorific value gas butterfly valve (1.2), a low calorific value gas blind plate valve (1.3), a low calorific value gas regulating and shut-off valve (1.4), a low calorific value gas flow meter (1.5), a low calorific value gas section flow meter (1.6), a low calorific value gas section regulating and shut-off valve (1.7), and a low calorific value gas reversing valve (1.8) in sequence; Along the fuel flow direction, a pipeline connecting the high calorific value gas pipeline (5.1) and the third burner group (8.3) is provided with a high calorific value gas butterfly valve (5.2), a high calorific value gas blind plate valve (5.3), a high calorific value gas regulating and shut-off valve (5.4), a high calorific value gas flow meter (5.5), a high calorific value gas section flow meter (5.6), and a high calorific value gas section regulating and shut-off valve (5.7) in sequence.

11. The combustion control system according to claim 10, characterized in that: Along the air flow direction, a combustion-supporting fan (3.1), an air flow meter (3.5), a first air section flow meter (3.6), a first air section regulating shut-off valve (3.7), and an air reversing valve (3.8) are sequentially arranged on the pipeline connecting the first air duct (3.4) and the first burner group (8.1) and the second burner group (8.2); Along the air flow direction, a second air section flow meter (6.1), a second air section regulating shut-off valve (6.2), a hot air release valve (6.5), and an air preheater (6.6) are sequentially arranged on the pipeline connecting the second air duct (6.3) and the third burner group (8.3).

12. The combustion control system according to claim 11, characterized in that: Along the flue gas flow direction, the low calorific value coal smoke pipe (2.2) is provided with a low calorific value coal smoke reversing valve (2.5), a low calorific value coal smoke regulating and shutting valve (2.4), a low calorific value coal smoke exhaust fan (2.3), and a low calorific value coal smoke chimney (2.1) in sequence, and the air smoke pipe (4.2) is provided with an air smoke reversing valve (4.5), an air smoke regulating and shutting valve (4.4), an air smoke exhaust fan (4.3), and an air smoke chimney (4.1) in sequence.

13. The combustion control system according to claim 12, characterized in that: The air smoke pipe (4.2) is connected to the air burner front header (3.9), and the connection relationship between the pipes is switched through the air reversing valve (3.8) and the air smoke reversing valve (4.5); the low calorific value coal smoke pipe (2.2) is connected to the low calorific value burner front header (1.9), and the connection relationship between the pipes is switched through the low calorific value coal smoke reversing valve (2.5) and the low calorific value coal gas reversing valve (1.8).

14. The combustion control system according to claim 12, characterized in that: The reversing valves on the burners located on the same side of the furnace wall of the heating furnace (8) are in an interlocking relationship and are in the opposite state to the reversing valves on the burners on the opposite side; The interlocking relationship is as follows: the states of the low calorific value coal gas reversing valve (1.8) and the air reversing valve (3.8) are consistent, and the states of the low calorific value coal smoke reversing valve (2.5) and the air smoke reversing valve (4.5) are consistent and opposite to the states of the low calorific value coal gas reversing valve (1.8) and the air reversing valve (3.8).

15. A combustion control method for cooperative heating of high and low calorific value coal gases, applied to the combustion control system for cooperative heating of high and low calorific value coal gases according to claim 1, characterized in that: include: Furnace temperature control: regulating the flow rates of the low calorific value gas pipeline (1.1), the high calorific value gas pipeline (5.1), the first air pipeline (3.4) and the second air pipeline (6.3) to control the difference between the actual temperature T1 and the set temperature T2 of the temperature control zone of the heating furnace (8) to not exceed 10°C; Furnace pressure control: regulating the flow rates of the low calorific value coal smoke pipes (2.2), the empty smoke pipes (4.2) and the conventional smoke exhaust pipes (7.2) to control the difference between the actual pressure P1 and the set pressure P2 of the furnace of the heating furnace (8) to not exceed 5 Pa.

16. The combustion control method according to claim 15, characterized in that: When T1≥T2 and T1-T2>10°C, the switching cycle of the low calorific value coal gas pipeline (1.1), the low calorific value coal smoke pipeline (2.2), the first air pipeline (3.4) and the air smoke pipeline (4.2) remains unchanged, and the flow rates of the low calorific value coal gas pipeline (1.1), the low calorific value coal smoke pipeline (2.2), the first air pipeline (3.4) and the air smoke pipeline (4.2) are reduced.

17. The combustion control method according to claim 15, characterized in that: When 10°C≤T2-T1≤30°C, the switching cycle of the low calorific value coal gas pipeline (1.1), the low calorific value coal smoke pipeline (2.2), the first air pipeline (3.4) and the air smoke pipeline (4.2) remains unchanged, and the flow rates of the low calorific value coal gas pipeline (1.1), the low calorific value coal smoke pipeline (2.2), the first air pipeline (3.4) and the air smoke pipeline (4.2) are increased.

18. The combustion control method according to claim 15, characterized in that: When T2-T1>30°C, the switching period of the low calorific value coal gas pipeline (1.1), the low calorific value coal smoke pipeline (2.2), the first air pipeline (3.4) and the air smoke pipeline (4.2) is extended so that the temperature of the low calorific value coal gas pipeline (1.1) and the first air pipeline (3.4) at the burner inlet is ≤180°C; and the flow rates of the low calorific value coal gas pipeline (1.1), the low calorific value coal smoke pipeline (2.2), the first air pipeline (3.4) and the air smoke pipeline (4.2) are increased.

19. The combustion control method according to claim 15, characterized in that: When P1≥P2, the flow rates of the low calorific value coal smoke pipeline (2.2) and the air smoke pipeline (4.2) are increased, and / or the flow rate of the conventional smoke exhaust pipeline (7.2) is increased; at the same time, the temperature of the low calorific value coal gas pipeline (1.1) and the first air pipeline (3.4) at the burner inlet is ensured to be ≤180°C.

20. The combustion control method according to claim 15, characterized in that: When P1≤P2, the flow rates of the low calorific value coal smoke pipeline (2.2) and the air smoke pipeline (4.2) are reduced, and / or the flow rate of the conventional smoke exhaust pipeline (7.2) is reduced, while ensuring that the temperature of the low calorific value coal gas pipeline (1.1) and the first air pipeline (3.4) at the burner inlet is ≤180°C.

21. The combustion control method according to claim 15, characterized in that: During the furnace pressure control process, If the temperature of the low calorific value coal gas pipeline (1.1) and the first air pipeline (3.4) at the burner inlet is ≤180°C, the furnace pressure is adjusted by adjusting the flow of the low calorific value coal smoke pipeline (2.2) and the air smoke pipeline (4.2); If the temperature of the low calorific value gas pipeline (1.1) and the first air pipeline (3.4) at the burner inlet is greater than 180° C., the furnace pressure is adjusted by adjusting the flow rate of the conventional smoke exhaust pipeline (7.2); If the temperature of the low calorific value coal gas pipeline (1.1) and the first air pipeline (3.4) at the burner inlet is ≤180°C, and the furnace pressure cannot be brought up to standard by only adjusting the flow rates of the low calorific value coal smoke pipeline (2.2) and the air smoke pipeline (4.2), the flow rate of the conventional smoke exhaust pipeline (7.2) is adjusted at the same time to bring the furnace pressure up to standard.

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