Multi-gas mixing system and method suitable for steel low-heating-value gas turbine

Abstract

The invention discloses a multi-gas mixing system and method suitable for a steel low-heating-value gas turbine. Comprising the following steps: mixing blast furnace gas and converter gas in a first gas pipeline mixer and then outputting first mixed gas; the first mixed gas and the coke oven gas are mixed in a second gas pipeline mixer, and then second mixed gas is output; the second mixed gas is conveyed to a gas compressor to be compressed; a mixed gas calorific value instrument is mounted on the communicating pipe; a coke oven gas regulating valve is mounted on the coke oven gas pipeline; the coke oven gas regulating valve is in signal connection with the mixed gas calorific value instrument; the opening degree of the coke oven gas regulating valve is subjected to feedback regulation through a calorific value signal of the mixed gas calorific value instrument. Through blending combustion of the converter gas, the adaptability of the steel low-heating-value gas turbine to fuel is expanded, and the flexible adjusting capacity of a gas system of the gas turbine is improved.

Description

Technical Field

[0001] The invention relates to the technical field of power generation by-product gas of steel enterprises, and in particular to a multi-gas blending system and method suitable for steel low calorific value gas gas turbines. Background Art

[0002] During the smelting process, steel enterprises will produce a large amount of by-product gas, including blast furnace gas, converter gas, coke oven gas, etc. In addition to the consumption of each smelting process, there is generally still some surplus gas, especially blast furnace gas. In order to make efficient use of the remaining low-calorific value gas, steel mills generally build low-calorific value gas generator sets. Among them, CCPP (combined cycle gas-steam power generation) is more efficient than the conventional BTG (boiler-turbine power generation) route, which is beneficial for steel mills to increase their self-generation rate and reduce carbon emissions. It has good comprehensive benefits and has been applied in many domestic steel mills and has achieved good operating results.

[0003] The design fuel of the low calorific value gas CCPP gas turbine is a dual fuel combination of blast furnace gas and coke oven gas, in which blast furnace gas is the main fuel and coke oven gas plays a role in calorific value regulation to control the calorific value of the mixed gas within the set range. However, in actual production, some steel mills may have insufficient surplus coke oven gas, while steel mills may have surplus converter gas. Therefore, how to make the low calorific value gas gas turbine burn converter gas on the basis of mixed burning of blast furnace gas and coke oven gas to improve the adaptability of the CCPP unit is a practical issue that steel mills are more concerned about.

[0004] However, there are certain difficulties in the blending of converter gas: unlike the relatively stable characteristics of natural gas, the calorific value and flow rate of steel plant blast furnace gas, converter gas and coke oven gas all fluctuate greatly, especially converter gas, which has very large flow rate and volatility. How to add converter gas with greater flow rate and calorific value fluctuations as a supplementary fuel to the blast furnace gas-coke oven gas fuel combination that already has a certain volatility, and most importantly, how to meet the strict requirements of gas turbines for fuel calorific value fluctuations, is a technical problem that needs to be urgently solved for the blending of converter gas. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the object of the present invention is to provide a multi-gas blending system suitable for steel low calorific value gas gas turbines.

[0006] To achieve the above object, the multi-gas blending system of the present invention, which is applicable to a steel low calorific value gas gas turbine, comprises: a converter gas pipeline, a blast furnace gas pipeline and a coke oven gas pipeline;

[0007] The converter gas pipeline and the blast furnace gas pipeline are connected to the inlet of the first gas pipeline mixer, and the blast furnace gas and the converter gas are mixed in the first gas pipeline mixer and then output through the first mixed gas pipeline at the outlet of the first gas pipeline mixer;

[0008] The first mixed coal gas pipeline and the coke oven gas pipeline are connected to the inlet of the second coal gas pipeline mixer, and the first mixed coal gas and the coke oven gas are mixed in the second coal gas pipeline mixer and then output through the second mixed gas pipeline at the outlet of the second coal gas pipeline mixer;

[0009] The second mixed gas pipeline is connected to the gas inlet of the gas compressor through a connecting pipe to deliver the gas to the gas compressor for compression;

[0010] A mixed gas calorific value meter is installed on the connecting pipe;

[0011] A coke oven gas regulating valve is installed on the coke oven gas pipeline; the coke oven gas regulating valve is connected to the mixed gas calorific value meter signal, and the opening of the coke oven gas regulating valve is feedback-regulated by the calorific value signal of the mixed gas calorific value meter;

[0012] A converter gas flowmeter and a converter gas regulating valve are provided on the converter gas pipeline; the converter gas regulating valve is connected to the converter gas flowmeter signal, and the opening of the converter gas regulating valve is feedback-regulated according to the flow signal of the converter gas flowmeter.

[0013] Furthermore, a gas dust collector is provided between the second mixed gas pipeline and the gas compressor.

[0014] Furthermore, the system also includes a gas reflux cooler;

[0015] One end of the gas reflux cooler is connected to the gas outlet of the gas compressor, and the other end is connected to the gas inlet of the gas dust collector, so as to quickly reflux and cool the high-temperature gas at the outlet of the gas compressor and send it to the inlet of the gas dust collector for recycling.

[0016] Furthermore, the system also includes a combustion chamber, an air compressor, a gas turbine, and a generator, wherein:

[0017] The gas outlet of the gas compressor and the air outlet of the air compressor are both connected to the combustion chamber. The gas and air are burned in the combustion chamber to generate high-temperature and high-pressure flue gas. The flue gas outlet of the combustion chamber is connected to the flue gas inlet of the gas turbine.

[0018] The generator is connected with the gas compressor, the air compressor and the gas turbine through a coupling or a gear box, and the gas turbine drives the generator to generate electricity.

[0019] Furthermore, it also includes a gas turbine control system and a generator set distributed control system DCS, wherein:

[0020] The gas turbine control system is responsible for the control of the gas turbine system. The signal of the mixed gas calorific value meter is connected to the gas turbine control system so as to automatically control the coke oven gas regulating valve through the gas turbine control system.

[0021] The generator set distributed control system DCS is responsible for the unified control of all supporting main and auxiliary systems of the generator set. The signal of the coke oven gas flow meter is connected to the generator set distributed control system DCS, and then the converter gas regulating valve is automatically controlled through the generator set distributed control system DCS.

[0022] Furthermore, a converter gas shut-off valve is installed on the converter gas pipeline to quickly shut off the converter gas entering the first gas mixer from the converter gas pipeline; and / or,

[0023] A coke oven gas cut-off valve is also installed on the coke oven gas pipeline to quickly cut off the coke oven gas entering the second gas mixer from the coke oven gas pipeline.

[0024] Further, a blast furnace gas flow meter is installed on the blast furnace gas pipeline to monitor the blast furnace gas flow in the blast furnace gas pipeline; and / or,

[0025] A converter gas flowmeter is installed on the converter gas pipeline to monitor the converter gas flow in the converter gas pipeline.

[0026] Furthermore, a converter gas pressure fan is installed along the converter gas pipeline to pressurize the converter gas so that the converter gas can smoothly enter the first gas mixer; and / or,

[0027] A coke oven gas pressurizing fan is also installed along the coke oven gas pipeline to pressurize the coke oven gas so that the coke oven gas can smoothly enter the second gas mixer;

[0028] To achieve the above object, the multi-gas blending method applicable to a steel low calorific value gas gas turbine of the present invention comprises the following steps: blast furnace gas and converter gas are mixed in a first gas pipeline mixer and then a first mixed gas is output;

[0029] The first mixed coal gas and the coke oven gas are mixed in the second gas pipeline mixer and then output as the second mixed coal gas;

[0030] The second mixed coal gas is sent to a coal gas compressor for compression;

[0031] Among them, blast furnace gas is used as the main fuel to ensure the necessary gas flow rate under the operating load of the gas turbine, and its flow rate is not controlled separately during the blending process;

[0032] Converter gas is used as auxiliary fuel. During the blending process, a flow control strategy is adopted. The opening of the coke oven gas regulating valve is adjusted with the set coke oven gas flow value as the target, and only the coke oven gas with a limited flow is allowed to enter the gas turbine.

[0033] Coke oven gas is used as the adjustment fuel, and a calorific value control strategy is adopted during the blending process. The opening of the converter gas regulating valve is adjusted based on the set calorific value of the mixed gas at the gas compressor inlet, ensuring that the calorific value of the gas finally entering the gas turbine meets the set requirements.

[0034] The present invention has the following advantages:

[0035] 1) By blending with converter gas, compared with the previous conventional scheme of using only blast furnace gas and coke oven gas as fuel, the adaptability of steel low calorific value gas gas turbine to fuel has been expanded, and the flexible adjustment capability of the gas system of the gas turbine has been improved.

[0036] 2) It can absorb the surplus converter gas of the steel plant, reduce the consumption of coke oven gas, and make better quality coke oven gas available for other purposes.

[0037] 3) By utilizing excess converter gas through gas turbines, the same amount of gas can generate more power output compared to conventional BTG gas power generation units, thereby creating incremental economic benefits.

[0038] 4) It can reduce the dependence of gas turbines on coke oven gas and improve the applicability of the advanced technology of steel low calorific value gas gas turbine power generation in steel mills. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the structural connection relationship of the present invention.

[0040] In the figure: 1. blast furnace gas pipeline; 2. converter gas pipeline; 3. coke oven gas pipeline; 4. converter gas booster fan; 5. converter gas flowmeter; 6. converter gas regulating valve; 7. converter gas shut-off valve; 8. first gas mixer; 9. blast furnace gas flowmeter; 10. coke oven gas booster fan; 11. coke oven gas flowmeter; 12. coke oven gas regulating valve; 13. coke oven gas shut-off valve; 14. second gas mixer; 15. first mixed gas pipeline; 16. second mixed gas pipeline; 17. gas dust collector; 18. gas compressor; 19. gas reflux cooler; 20. combustion chamber; 21. air compressor; 22. gas turbine; 23. generator; 24. gas calorific value meter; 25. gas turbine control system; 26. generator set distributed control system DCS. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Example 1

[0046] Figure 1The invention is an embodiment of a multi-gas blending system suitable for a steel low calorific value gas gas turbine, comprising a blast furnace gas pipeline 1, a converter gas pipeline 2, a coke oven gas pipeline 3, a converter gas regulating valve 6, a first gas mixer 8, a coke oven gas flow meter 11, a coke oven gas regulating valve 12, a second gas mixer 14, a first mixed gas pipeline 15, a second mixed gas pipeline 16, a gas dust collector 17, a gas compressor 18, and a mixed gas calorific value meter 24, wherein:

[0047] The blast furnace gas pipeline 1 is connected to the blast furnace gas inlet of the first gas pipeline mixer 8, the converter gas pipeline 2 is connected to the converter gas inlet of the first gas pipeline mixer 8, and the blast furnace gas and the converter gas are mixed in the first gas pipeline mixer 8;

[0048] One end of the first mixed gas pipeline 15 is connected to the gas outlet of the first gas pipeline mixer 8, and the other end is connected to the mixed gas inlet of the second gas pipeline mixer 14;

[0049] The coke oven gas pipeline 3 is connected to the coke oven gas inlet of the second gas pipeline mixer 14, and the coke oven gas is mixed with the mixed gas in the first mixed gas pipeline 15 in the second gas mixer 14;

[0050] One end of the second mixed gas pipeline 16 is connected to the gas outlet of the second gas pipeline mixer 14, and the other end is connected to the gas inlet of the gas dust collector 17;

[0051] The gas outlet of the gas dust collector 17 is connected to the gas inlet of the gas compressor 18, and the gas is sent to the gas compressor for compression. A mixed gas calorific value meter 24 is installed on the connecting pipe;

[0052] The converter gas flow meter 5 and the converter gas regulating valve 6 are installed on the converter gas pipeline 2. The converter gas regulating valve 6 is connected to the converter gas flow meter 5 by signal. The opening of the converter gas regulating valve 6 is feedback-regulated according to the flow signal of the converter gas flow meter 5.

[0053] The coke oven gas regulating valve 12 is installed on the coke oven gas pipeline 3 , and the coke oven gas regulating valve 12 is connected to the mixed gas calorific value meter 24 by signal, and the opening of the coke oven gas regulating valve 12 is feedback-regulated by the calorific value signal of the mixed gas calorific value meter 24 .

[0054] Example 2

[0055] On the basis of the above embodiment, a converter gas cut-off valve 7 is further installed on the converter gas pipeline 2, which can quickly cut off the converter gas entering the first gas mixer 8 from the converter gas pipeline 2;

[0056] A coke oven gas shut-off valve 13 is also installed on the coke oven gas pipeline 3 , which can quickly shut off the coke oven gas entering the second gas mixer 14 from the coke oven gas pipeline 3 .

[0057] Example 3

[0058] On the basis of the above embodiment, a blast furnace gas flow meter 9 is further installed on the blast furnace gas pipeline 1 to monitor the blast furnace gas flow in the blast furnace gas pipeline 1;

[0059] A converter gas flowmeter 5 is also installed on the converter gas pipeline 2 for monitoring the converter gas flow in the converter gas pipeline 2 .

[0060] Example 4

[0061] On the basis of the above embodiment, a converter gas pressure fan 5 is further installed along the converter gas pipeline 2 for pressurizing the converter gas so that the converter gas can smoothly enter the first gas mixer 8 .

[0062] Example 5

[0063] On the basis of the above embodiment, a coke oven gas pressurizing blower 10 is further installed along the coke oven gas pipeline 3 for pressurizing the coke oven gas so that the coke oven gas can smoothly enter the second gas mixer 14 .

[0064] Example 6

[0065] On the basis of the above-mentioned embodiment, the above-mentioned multi-gas blending system applicable to the steel low calorific value gas gas turbine further includes a gas reflux cooler 19, a combustion chamber 20, an air compressor 21, a gas turbine 22, and a generator 23, wherein:

[0066] One end of the gas reflux cooler 19 is connected to the gas outlet of the gas compressor 18, and the other end is connected to the gas inlet of the gas dust collector 17. The function of the gas reflux cooler 19 is to quickly reflux and cool the high-temperature gas at the outlet of the gas compressor 18 when the gas turbine is under load reduction or load rejection, and send it to the inlet of the gas dust collector 17 for recycling;

[0067] The gas outlet of the gas compressor 18 and the air outlet of the air compressor 21 are both connected to the combustion chamber 20. The gas and air are burned in the combustion chamber 20 to generate high-temperature and high-pressure flue gas. The flue gas outlet of the combustion chamber 20 is connected to the flue gas inlet of the gas turbine 22.

[0068] The generator 23 is connected to the gas compressor 18, the air compressor 21, and the gas turbine 22 via a coupling or a gear box, and the gas turbine drives the generator 23 to generate electricity.

[0069] Example 7

[0070] On the basis of the above-mentioned embodiment, the above-mentioned multi-gas blending system applicable to the steel low calorific value gas gas turbine further includes a gas turbine control system 25 and a generator set distributed control system DCS26, wherein:

[0071] The gas turbine control system 25 is responsible for controlling the gas turbine system. The signal of the mixed gas calorific value meter 24 is connected to the gas turbine control system 25, and then the coke oven gas regulating valve 12 is automatically controlled by the gas turbine control system 25;

[0072] The generator set distributed control system DCS26 is responsible for the unified control of all supporting main and auxiliary systems of the generator set. The signal of the converter gas flow meter 5 is connected to the generator set distributed control system DCS26, and then the converter gas regulating valve 6 is automatically controlled by the generator set distributed control system DCS26.

[0073] Example 8

[0074] The present invention is a multi-gas blending method applicable to a steel low calorific value gas gas turbine, which is implemented based on the system of the above embodiment, wherein:

[0075] Blast furnace gas is used as the main fuel to ensure the necessary gas flow rate under the operating load of the gas turbine, and its flow rate is not controlled separately during the blending process;

[0076] Converter gas is used as an auxiliary fuel. A flow control strategy is adopted during the blending process. The opening of the converter gas regulating valve is adjusted based on the set converter gas flow value, and only converter gas with a limited flow rate is allowed to enter the gas turbine.

[0077] Coke oven gas is used as the adjustment fuel. A calorific value control strategy is adopted during the blending process. The opening of the coke oven gas regulating valve is adjusted based on the set calorific value of the mixed gas at the gas compressor inlet to ensure that the calorific value of the mixed gas finally entering the gas turbine meets the set requirements.

[0078] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0079] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A multi-gas blending system suitable for steel low calorific value gas turbine, characterized in that: The system comprises: a converter gas pipeline, a blast furnace gas pipeline and a coke oven gas pipeline; The converter gas pipeline and the blast furnace gas pipeline are connected to the inlet of the first gas pipeline mixer, and the blast furnace gas and the converter gas are mixed in the first gas pipeline mixer and then output through the first mixed gas pipeline at the outlet of the first gas pipeline mixer; The first mixed coal gas pipeline and the coke oven gas pipeline are connected to the inlet of the second coal gas pipeline mixer, and the first mixed coal gas and the coke oven gas are mixed in the second coal gas pipeline mixer and then output through the second mixed gas pipeline at the outlet of the second coal gas pipeline mixer; The second mixed gas pipeline is connected to the gas inlet of the gas compressor through a connecting pipe to deliver the gas to the gas compressor for compression; A mixed gas calorific value meter is installed on the connecting pipe; A coke oven gas regulating valve is installed on the coke oven gas pipeline; the coke oven gas regulating valve is connected to the mixed gas calorific value meter signal, and the opening of the coke oven gas regulating valve is feedback-regulated by the calorific value signal of the mixed gas calorific value meter; A converter gas flowmeter and a converter gas regulating valve are provided on the converter gas pipeline; the converter gas regulating valve is connected to the converter gas flowmeter signal, and the opening of the converter gas regulating valve is feedback-regulated according to the flow signal of the converter gas flowmeter.

2. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 1, characterized in that: A gas dust collector is arranged between the second mixed gas pipeline and the gas compressor.

3. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 2, characterized in that: The system also includes a gas reflux cooler; One end of the gas reflux cooler is connected to the gas outlet of the gas compressor, and the other end is connected to the gas inlet of the gas dust collector, so as to quickly reflux and cool the high-temperature gas at the outlet of the gas compressor and send it to the inlet of the gas dust collector for recycling.

4. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 3, characterized in that: The system further comprises a combustion chamber, an air compressor, a gas turbine, and a generator, wherein: The gas outlet of the gas compressor and the air outlet of the air compressor are both connected to the combustion chamber. The gas and air are burned in the combustion chamber to generate high-temperature and high-pressure flue gas. The flue gas outlet of the combustion chamber is connected to the flue gas inlet of the gas turbine. The generator is connected with the gas compressor, the air compressor and the gas turbine through a coupling or a gear box, and the gas turbine drives the generator to generate electricity.

5. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 4, characterized in that: It also includes gas turbine control system and generator set distributed control system DCS, including: The gas turbine control system is responsible for the control of the gas turbine system. The signal of the mixed gas calorific value meter is connected to the gas turbine control system so as to automatically control the coke oven gas regulating valve through the gas turbine control system. The DCS of the generator set is responsible for the unified control of all the supporting main and auxiliary systems of the generator set. The signal of the coke oven gas flow meter is connected to the DCS of the generator set, and then the converter gas regulating valve is automatically controlled by the DCS of the generator set.

6. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 1, characterized in that: A converter gas shut-off valve is also installed on the converter gas pipeline to quickly shut off the converter gas entering the first gas mixer from the converter gas pipeline; and / or, A coke oven gas cut-off valve is also installed on the coke oven gas pipeline to quickly cut off the coke oven gas entering the second gas mixer from the coke oven gas pipeline.

7. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 1, characterized in that: A blast furnace gas flow meter is installed on the blast furnace gas pipeline to monitor the blast furnace gas flow in the blast furnace gas pipeline; and / or, A converter gas flowmeter is installed on the converter gas pipeline to monitor the converter gas flow in the converter gas pipeline.

8. The multi-gas blending system suitable for steel low calorific value gas turbine according to claim 1, characterized in that: A converter gas pressure fan is also installed along the converter gas pipeline to pressurize the converter gas so that the converter gas can smoothly enter the first gas mixer; and / or, A coke oven gas pressurizing fan is also installed along the coke oven gas pipeline to pressurize the coke oven gas so that the coke oven gas can smoothly enter the second gas mixer.

9. A multi-gas blending method suitable for steel low calorific value gas turbine, characterized in that: The method comprises the following steps: blast furnace gas and converter gas are mixed in a first gas pipeline mixer and then a first mixed gas is output; The first mixed coal gas and the coke oven gas are mixed in the second gas pipeline mixer and then output as the second mixed coal gas; The second mixed coal gas is sent to a coal gas compressor for compression; Among them, blast furnace gas is used as the main fuel to ensure the necessary gas flow rate under the operating load of the gas turbine, and its flow rate is not controlled separately during the blending process; Converter gas is used as auxiliary fuel. During the blending process, a flow control strategy is adopted. The opening of the coke oven gas regulating valve is adjusted with the set coke oven gas flow value as the target, and only the coke oven gas with a limited flow is allowed to enter the gas turbine. Coke oven gas is used as the adjustment fuel, and a calorific value control strategy is adopted during the blending process. The opening of the converter gas regulating valve is adjusted based on the set calorific value of the mixed gas at the gas compressor inlet, ensuring that the calorific value of the gas finally entering the gas turbine meets the set requirements.

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