Combustion control method for generator sets adapting to large fluctuations in gas pressure and gas volume

Abstract

The invention relates to the field of blast furnace gas automatic control, and provides a combustion control method for a generator set adapting to large fluctuations in gas pressure and gas volume. The method comprises the following steps: limiting the speed of blast furnace gas pressure to obtain a set value of blast furnace gas pressure, and using the set value as a boiler main control set value; when the blast furnace gas output changes, stabilizing the set value of blast furnace gas pressure at a specific pressure point by controlling the opening of valves of the same operation part; determining an oxygen target value according to a main steam flow, obtaining an air volume set value and a fuel volume set value according to the output of the boiler main control, and obtaining a final air volume set value according to the oxygen target value and the air volume set value; using the final air volume set value as a target value of fan air volume after being limited by a minimum air volume; limiting the upper limit of the fuel volume set value by the actual air volume, limiting the lower limit of the air volume set value by the actual gas volume, adding or subtracting air and fuel in a load-changing process, and ensuring the proportion of air volume and gas volume in the load-changing process.

Description

Technical Field

[0001] The invention relates to the field of blast furnace gas automatic control, and in particular to a combustion control method for a generator set adapting to large fluctuations in gas pressure and gas volume. Background Art

[0002] Since some steel enterprises have no pressure stabilization measures in the gas pipeline network, there are many gas users, and the pressure of the gas pipeline network fluctuates greatly, how to ensure that the gas pipeline network is maintained within a certain pressure range and realize automatic combustion of the boiler in the gas generator unit of the self-provided power plant is a thorny problem. The existing solutions and specifications are generally: the first case is that the gas pipeline network adds gas pressure stabilization equipment, such as installing a gas tank, to stabilize the boiler fuel. This method can solve the above problems, but the investment and floor space are large; the second case is that without adding pressure stabilization measures, most enterprises adopt the method of increasing operating personnel, always paying attention to the pressure of the gas pipeline network, and frequently manually operating the unit boiler, steam turbine, auxiliary equipment and other equipment according to the pressure changes. This method can also meet production needs, but it requires high technical level of operating personnel and high labor intensity of operating personnel. Generally, the high pressure of the pipeline network is maintained to ensure the normal production of other processes, and gas emission waste occurs for a long time. Maintaining low pressure will affect the production of other processes and production efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide a combustion control method for a generator set that is adaptable to large fluctuations in gas pressure and gas volume, which does not require additional large investments and can enable the boiler of a gas generator set to automatically control combustion according to gas changes.

[0004] The present invention solves the technical problem and adopts the following technical solution:

[0005] A combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume comprises the following steps:

[0006] The blast furnace gas pressure is speed-limited to obtain a set value of the blast furnace gas pressure, which is used as a boiler main control set value;

[0007] When the blast furnace gas output changes, the setting value of the blast furnace gas pressure is stabilized at a specific pressure point by controlling the opening of the valves in the same operation part;

[0008] The oxygen target value is determined according to the main steam flow, the air volume set value and the fuel volume set value are obtained according to the output of the boiler master control, and the final air volume set value is obtained according to the oxygen target value and the air volume set value;

[0009] The final air volume setting value is used as the target value of the fan air volume after passing the minimum air volume limit;

[0010] Use the actual air volume to limit the upper limit of the fuel volume setting value, and use the actual gas volume to limit the lower limit of the air volume setting value. Add or subtract air and fuel during the load change process to ensure the ratio of air volume and gas volume during the load change process.

[0011] Furthermore, the speed limiting of the blast furnace gas pressure to obtain the set value of the blast furnace gas pressure specifically refers to: dividing the actual pipeline pressure, that is, the blast furnace gas into two paths, one path is input into the filter speed limiter to obtain the first set value of the blast furnace gas pressure, and input it into the subtractor, and the other path inputs the actual pipeline pressure into the subtractor, and after the difference operation is performed between the actual pipeline pressure and the first set value, it is input to the boiler main regulator, and after the operation of the boiler main regulator, the set value of the blast furnace gas pressure is obtained.

[0012] Furthermore, blast furnace gas is used to regulate the normal operation of the gas boiler. During the regulation process, there is an regulating main valve entering each layer of burners, and there is an regulating sub-valve entering each burner. The burner main valve is adjusted by manual operation, and the regulating sub-valves of each layer of burners can be operated simultaneously, that is, all valves of the burners on the same layer can be operated simultaneously through an operating panel, and each sub-valve has its own bias, so that the opening of the sub-valve has a fixed deviation from the opening set by the same operator.

[0013] Furthermore, when the blast furnace gas production volume changes, the set value of the blast furnace gas pressure is stabilized at a specific pressure point by controlling the opening of the valves of the same operation part, specifically:

[0014] When the blast furnace gas production increases and the blast furnace gas pressure rises, the set value of the blast furnace gas pressure also increases, and the rate of increase is limited. At this time, the opening of the same operating part is increased to stabilize the blast furnace gas pressure, that is, the opening of the burner valve is increased to match the increase in blast furnace gas pressure;

[0015] When the blast furnace gas production decreases, the output value of the same operator closes the valve opening to reduce gas consumption, slow down the rate of blast furnace gas decline, and stabilize the set value of blast furnace gas pressure at a specific pressure point.

[0016] Furthermore, when there is a large deviation between the set value and actual pressure of the blast furnace gas pressure, it means that the actual pressure is changing rapidly. At this time, a fast-adjusting parameter is used to ensure the stability of the pipeline network pressure. When the blast furnace gas pressure rises or falls to a certain amplitude, the set value will no longer continue to rise or fall, and the gas boiler will no longer consider load stability, and all of it will be used to stabilize the pipeline network pressure.

[0017] Furthermore, obtaining the final air volume setting value according to the oxygen content target value and the air volume setting value specifically refers to: air volume setting value×oxygen content correction value+air volume offset=obtaining the final air volume setting value.

[0018] Furthermore, the secondary air damper entering the furnace is controlled according to the operation status of the corresponding burner and the main steam flow rate: a reasonable curve is fitted according to the data of different loads running for a long time, and each valve is set with a corresponding offset, or the valves of the upper front wall and / or upper rear wall and / or lower burner valves are operated at the same time.

[0019] Furthermore, the boiler induced draft fan is regulated by total air volume feedforward, total gas volume feedforward and actual furnace pressure.

[0020] Furthermore, when the total air volume and the total gas volume are used as feedforward to enter the induced draft automatic regulation, the blast furnace gas and the coke oven gas are considered respectively, and at the same time, the induced draft fan strengthens the feedforward effect of the furnace pressure.

[0021] The beneficial effects of the present invention are as follows: through the above-mentioned combustion control method for generator sets that adapt to large fluctuations in gas pressure and gas volume, the present invention does not require additional large investments and can enable the boiler of the gas generator set to automatically control combustion according to changes in gas. At the same time, the present invention can avoid the waste of gas release caused by untimely manual operation by operating personnel or affect the normal production of other processes. In addition, the present invention also avoids the problem of frequent manual operation and high labor intensity by operating personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of the combustion control method for a generator set proposed by the present invention that is adaptable to large fluctuations in gas pressure and gas volume. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0024] The present invention proposes a combustion control method for a generator set that is adaptable to large fluctuations in gas pressure and gas volume. Figure 1 , wherein the method comprises the following steps:

[0025] S1. Limit the blast furnace gas pressure to obtain a set value for the blast furnace gas pressure, which is used as the boiler master control set value;

[0026] S2. When the blast furnace gas production volume changes, the setting value of the blast furnace gas pressure is stabilized at a specific pressure point by controlling the opening of the valves of the same operation part;

[0027] S3. Determine the oxygen target value according to the main steam flow, obtain the air volume set value and the fuel volume set value according to the output of the boiler master control, and obtain the final air volume set value according to the oxygen target value and the air volume set value;

[0028] S4. The final air volume setting value is used as the target value of the fan air volume after passing the minimum air volume limit;

[0029] S5. Use the actual air volume to limit the upper limit of the fuel volume setting value, and use the actual gas volume to limit the lower limit of the air volume setting value. Add or subtract air and fuel during the load change process to ensure the ratio of air volume and gas volume during the load change process.

[0030] In the above method, the speed limiting of the blast furnace gas pressure to obtain the set value of the blast furnace gas pressure specifically refers to: dividing the actual pipeline pressure, that is, the blast furnace gas into two paths, one path is input into the filter speed limiter to obtain the first set value of the blast furnace gas pressure, and input it into the subtractor, and the other path inputs the actual pipeline pressure into the subtractor, and after the actual pipeline pressure is subtracted from the first set value, it is input to the boiler main regulator, and after the operation of the boiler main regulator, the set value of the blast furnace gas pressure is obtained.

[0031] The gas source of gas boilers is generally blast furnace gas and coke oven gas. The pressure and calorific value of coke oven gas are relatively stable and are generally used for ignition. Blast furnace gas is generally used to adjust the normal operation of gas boilers. Blast furnace gas is used to adjust the normal operation of gas boilers. During the adjustment process, there is a main regulating valve entering each layer of burners, and there is a regulating sub-valve entering each burner. The main valve of the burner is adjusted by manual operation. The regulating sub-valve of each layer of burners can be operated at the same time, that is, through an operation panel, all valves of the same layer of burners are operated at the same time, and each sub-valve has its own bias, so that the opening of the sub-valve has a fixed deviation from the opening set by the same operator. In this way, the opening of the sub-valve can have a fixed deviation from the opening set by the same operator. Since the entire adjustment process must consider the pipeline pressure, and the grid-side assessment such as AGC adjustment is generally not considered. Therefore, the boiler main control setting value is considered to be the blast furnace gas pressure, and the boiler main control output is the gas volume, which is sent to the setting value of the gas volume same-operation module and the setting value for the air volume after the conversion of the fuel volume to the air volume.

[0032] It should be pointed out that when the blast furnace gas production changes, the setting value of the blast furnace gas pressure is stabilized at a specific pressure point by controlling the opening of the valves in the same operation part, specifically:

[0033] When the blast furnace gas production increases and the blast furnace gas pressure rises, the set value of the blast furnace gas pressure also increases, and the rate of increase is limited. At this time, the opening of the same operating part is increased to stabilize the blast furnace gas pressure, that is, the opening of the burner valve is increased to match the increase in blast furnace gas pressure;

[0034] When the blast furnace gas production decreases, the output value of the same operator closes the valve opening to reduce gas consumption, slow down the rate of blast furnace gas decline, and stabilize the set value of blast furnace gas pressure at a specific pressure point.

[0035] Specifically, the blast furnace gas pressure after speed limit is used as the set value of blast furnace gas pressure. When the blast furnace gas production increases and the blast furnace gas pressure rises, the set value of blast furnace gas pressure also increases, but the rate of increase is limited. In this way, the opening of the same operation part must be increased to stabilize the blast furnace gas pressure, that is, the opening of the burner valve is increased to match the increase in blast furnace gas pressure. When the blast furnace gas production decreases, the output value of the same operation will also close the valve opening to reduce the gas consumption and slow down the speed of blast furnace gas decline. This can not only stabilize the combustion, but also slow down the speed of change of blast furnace gas pressure, and finally stabilize at a specific pressure point. When the gas pressure set value and the actual pressure have a large deviation, it means that the actual pressure is changing rapidly. At this time, a fast adjustment parameter should be changed to ensure the stability of the pipeline network pressure. When the blast furnace gas pressure increases or decreases to a certain amplitude, the set value will no longer continue to increase or decrease, and the gas boiler will no longer consider load stability, and all of it is used to stabilize the pipeline network pressure.

[0036] In addition, further, obtaining the final air volume setting value according to the oxygen content target value and the air volume setting value specifically refers to: air volume setting value×oxygen content correction value+air volume offset=obtaining the final air volume setting value.

[0037] Here, since the boiler relies on the blower to control the total air volume. The target value of the oxygen content is determined according to the main steam flow of the boiler; the air volume setting value is obtained according to the output of the boiler master control, and the air volume setting value × oxygen correction value + air volume offset (the air volume manually adjusted on the operation screen) is used to obtain the final air volume setting value. The final air volume setting value is used as the target value of the fan air volume after the minimum air volume limit and is adjusted. This ensures that the fan and the fuel master control can obtain the required air volume and gas volume at the same time, and use the actual air volume to limit the upper limit of the gas volume setting value, and use the actual gas volume to limit the lower limit of the air volume setting value. This allows the wind and fuel to be quickly added or subtracted during the load change process, and the ratio of the wind and gas volume to be ensured during the load change process.

[0038] In actual application, the secondary air damper entering the furnace is controlled according to the operation status of the corresponding burner and the main steam flow rate: a reasonable curve is fitted according to the data of different loads during long-term operation, and each valve is set with a corresponding offset, or the valves of the upper front wall and / or upper rear wall and / or lower burner valves are operated at the same time. The secondary air damper entering the furnace is controlled according to the operation status of the corresponding burner and the main steam flow rate, and the operating personnel fit a reasonable curve based on past experience or long-term operation data of different loads, and each valve can be manually set with an offset, or several valves on the upper front wall can be operated at the same time, and the upper rear wall and lower burner valves can also be operated at the same time.

[0039] As a further preferred embodiment, the boiler induced draft fan is adjusted by total air volume feedforward, total gas volume feedforward and actual furnace pressure. When the total air volume and total gas volume are used as feedforward to enter the induced draft automatic adjustment, blast furnace gas and coke oven gas are considered respectively, and the induced draft fan strengthens the feedforward effect of the furnace pressure. Here, the boiler induced draft fan is adjusted by total air volume feedforward, total gas volume feedforward and actual furnace pressure. The total air volume and total gas volume are used as feedforward to enter the induced draft automatic adjustment, and blast furnace gas and coke oven gas are considered respectively, because their effects on the induced draft fan are completely different. This feedforward plays a greater role when the fuel pressure fluctuates greatly. At the same time, the induced draft fan needs to strengthen the feedforward effect of the furnace pressure, because the air volume and gas volume as feedforward cannot 100% compensate for the changes in furnace pressure caused by changes in gas volume.

[0040] Therefore, the present invention can automatically match the current pipeline network pressure, adaptively match the reasonable load according to the change of pipeline network pressure to maintain the stability of pipeline network pressure, and the boiler load changes relatively smoothly, and can respond quickly under abnormal circumstances.

Claims

1. A combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume, characterized in that: The steps include: The blast furnace gas pressure is speed-limited to obtain a set value of the blast furnace gas pressure, which is used as a boiler main control set value; The speed limiting of the blast furnace gas pressure to obtain the set value of the blast furnace gas pressure specifically refers to: dividing the actual pipe network pressure, that is, the blast furnace gas into two paths, one path is input into the filter speed limiter to obtain the first set value of the blast furnace gas pressure, and input it into the subtractor, and the other path inputs the actual pipe network pressure into the subtractor, performs a difference operation between the actual pipe network pressure and the first set value, and then inputs it into the boiler main regulator, and obtains the set value of the blast furnace gas pressure after the operation of the boiler main regulator; When the blast furnace gas output changes, the setting value of the blast furnace gas pressure is stabilized at a specific pressure point by controlling the opening of the valves in the same operation part; The oxygen target value is determined according to the main steam flow rate, the air volume setting value and the fuel volume setting value are obtained according to the output of the boiler master control, and the final air volume setting value is obtained according to the oxygen target value and the air volume setting value. The final air volume setting value is obtained according to the oxygen target value and the air volume setting value, specifically referring to: air volume setting value × oxygen correction value + air volume offset = final air volume setting value; The final air volume setting value is used as the target value of the fan air volume after passing the minimum air volume limit; Use the actual air volume to limit the upper limit of the fuel volume setting value, and use the actual gas volume to limit the lower limit of the air volume setting value. Add or subtract air and fuel during the load change process to ensure the ratio of air volume and gas volume during the load change process.

2. The combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume according to claim 1, characterized in that: Blast furnace gas is used to regulate the normal operation of the gas boiler. During the regulation process, there is an regulating main valve entering each layer of burners, and an regulating sub-valve entering each burner. The burner main valve is adjusted by manual operation, and the regulating sub-valve of each layer of burners can be operated simultaneously, that is, through an operating panel, all valves of the burner on the same layer are operated at the same time, and each sub-valve has its own bias, so that the opening of the sub-valve has a fixed deviation from the opening set by the same operator.

3. The combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume according to claim 1, characterized in that: When the blast furnace gas production changes, the setting value of the blast furnace gas pressure is stabilized at a specific pressure point by controlling the opening of the valves in the same operation part, specifically: When the blast furnace gas production increases and the blast furnace gas pressure rises, the set value of the blast furnace gas pressure also increases, and the rate of increase is limited. At this time, the opening of the same operating part is increased to stabilize the blast furnace gas pressure, that is, the opening of the burner valve is increased to match the increase in blast furnace gas pressure; When the blast furnace gas production decreases, the output value of the same operator closes the valve opening to reduce gas consumption, slow down the rate of blast furnace gas decline, and stabilize the set value of blast furnace gas pressure at a specific pressure point.

4. The combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume according to claim 3, characterized in that: When there is a large deviation between the set value and actual pressure of blast furnace gas pressure, it means that the actual pressure is changing rapidly. At this time, a fast-adjusting parameter is used to ensure the stability of the pipeline network pressure. When the blast furnace gas pressure rises or falls to a certain amplitude, the set value will no longer continue to rise or fall, and the gas boiler will no longer consider load stability, and all of it is used to stabilize the pipeline network pressure.

5. The combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume according to any one of claims 1 to 4, characterized in that: The secondary air damper entering the furnace is controlled according to the operation status of the corresponding burner and the main steam flow rate: a reasonable curve is fitted according to the data of different loads running for a long time, and each valve is set with a corresponding offset, or the valves of the upper front wall and / or upper rear wall and / or lower burner are operated at the same time.

6. The combustion control method for a generator set adapted to large fluctuations in gas pressure and gas volume according to claim 5, characterized in that: The boiler induced draft fan is regulated by total air volume feedforward, total gas volume feedforward and actual furnace pressure.

7. According to the combustion control method of a generator set adapted to large fluctuations in gas pressure and gas volume as described in claim 6, when the total air volume and total gas volume are used as feedforward to enter the induced draft automatic adjustment, blast furnace gas and coke oven gas are considered respectively, and at the same time, the induced draft fan strengthens the feedforward effect of the furnace pressure.

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