JP6547960B2 - Operating method when starting gas turbine and exhaust gas path device for gas turbine - Google Patents

Description

  The present invention relates to a method of operating a gas turbine at startup and an exhaust gas path device for a gas turbine that is useful when applied during the operation.

  Generally, in a thermal power plant or the like, a gas turbine is rotated using high-temperature and high-pressure combustion gas generated by burning fuel, and power is generated by a generator utilizing the rotational force. In this case, combustion gas and the like are directly introduced into the turbine, but it is common to clean the fuel gas and the combustion air and the like using a filter and the like on the inlet side of the turbine. That is, in the case of a gas turbine, conventionally, the fuel gas or the like on the upstream side (inlet side) is introduced after the purification process. As a result, the dust in the exhaust system combustion gas on the downstream side of the gas turbine, that is, on the outlet side is relatively small. Therefore, after the turbine is rotated by the combustion gas, the exhaust gas can usually be exhausted as it is, and it is usual not to reprocess the exhaust gas or to stop it to such an extent that a denitration facility is provided.

  Further, as another conventional technique, combined cycle power generation in which a waste heat recovery boiler is disposed downstream of the gas turbine, high temperature steam is generated by the waste heat recovery boiler, and heat is recovered by the steam turbine, and further a turbine There is also a coal gasification combined cycle power generation system or the like in which a cyclone and a gas purification device are disposed on the upstream side of (1).

  Furthermore, in the gas turbine disclosed in Patent Document 2, a dust removal filter is disposed on the upstream side (inlet side) of the turbine to send dust-free air to the compressor.

JP, 2011-214562, A JP 2011-140880 A

  As described above, in the case of the conventional gas turbine disclosed in Patent Documents 1 and 2, etc., after recovering the pressure and sensible heat of the combustion gas, the atmosphere is generally diffused as it is as the exhaust gas through the chimney etc. That's normal.

  By the way, since existing gas turbines are used after the combustion air is pre-dusted with a filter on the inlet side of the turbine, it is considered that the exhaust gas after fuel combustion contains almost no dust. However, this state is when the gas turbine is stably operated, and in this case, it can be said that the exhaust gas can be dissipated as it is without any problem. However, gas turbines sometimes stop operation for inspection or equipment repair. At such timing, air may flow into the passage through which the combustion gas (exhaust gas) flows, and iron rust may be generated due to temperature change or water inflow.

  In addition, particularly in combined cycle power generation that uses fuel containing sulfur such as coal gasification gas, by-product gas such as blast furnace gas, and sulfur such as heavy oil, the exhaust heat recovery boiler immediately after the gas turbine contains Since the sulfur contained is oxidized to form SOx, it reacts with the water in the combustion gas to form sulfuric acid, and this sulfuric acid reacts with the boiler tube to produce iron sulfate on the inner surface of the boiler tube. is there.

Furthermore, when operating a gas turbine, ammonia for NOx removal may be used in order to reduce NOx contained in exhaust gas, and in this case, ammonium sulfate (NH ₄ (NH _{4) is} generated by the reaction between ammonia for NOx removal and SOx. ₂ ) ₂ SO ₄ is generated, which adheres to the inner surface of the boiler tube of the heat recovery steam generator and can not be avoided.

  As described above, in a gas turbine containing sulfur in fuel and having exhaust heat recovery equipment, products such as iron sulfate and ammonium sulfate are inevitably produced and attached to the inner surface of the boiler tube by using the exhaust heat recovery equipment. It is believed to be growing.

  In this respect, when the gas turbine is operating in a steady state, the sulfur oxidation product reacted on the surface of the boiler tube as described above is in a state of adhering to the surface of the boiler tube and hence such products It does not come out of the chimney entrained by the combustion gas. However, as described above, the temperature of the boiler tube is lowered when the equipment is stopped such as inspection or repair of the equipment. Therefore, products such as iron rust, iron sulfate, and ammonium sulfate, which have been attached, may be exfoliated to form flakes due to thermal contraction or the like of the boiler tube at this time. Then, in such a case, when it is subsequently tried to start up the equipment (gas turbine), such iron rust, iron sulfate and ammonium sulfate peel off and become flaked, which is mixed in the exhaust gas and scattered from the chimney There was a risk of Such iron rust, iron sulfate and ammonium sulfate are dissipated as dust, which may lead to an undesirable situation on the environment.

  On the other hand, since such a problem does not occur during normal equipment operation, it is necessary to pay attention only to the start-up operation of the equipment as described above. Therefore, in the past, measures were taken to start only when the weather conditions are good, and to periodically clean the inside of the boiler, so that dust discharged from the chimney when starting the turbine was not scattered as much as possible. It is

  An object of the present invention is to provide a technology capable of obviating the problem of the scattering of dust and various flakes that may occur when starting such a turbine.

  The inventors of the present invention have been able to overcome the above-mentioned problems of the prior art and, as a result of earnestly studying to achieve the above-mentioned purpose, have developed the present invention characterized by the following configuration. It was

That is, according to the present invention, when the gas turbine is started to obtain driving force by burning the fuel gas, the main gas path can switch the exhaust gas path of the gas turbine through the flow path switching damper. During operation at the time of gas turbine start, exhaust gas is introduced into the bypass route and the exhaust gas is removed by a filter type dust collector using a heat resistant air filter disposed in the route. And, after completion of the dust removal operation at the time of starting the gas turbine, the exhaust gas is introduced to the main path.

Further, according to the present invention, an exhaust gas passage apparatus for a gas turbine which obtains a driving force by burning a fuel gas as used in an operation method at the time of starting the gas turbine, the exhaust gas passage, a flow path switching damper And a filter-type dust collector using a heat-resistant air filter for start-up operation is disposed in the bypass path, and is branched downstream of the filter-type dust collector. An exhaust gas path device of a gas turbine characterized in that a bypass path is connected to a main path is proposed.

In the present invention,
(1) The operation at the time of gas turbine startup should be completed by 6 hours after startup.
(2) operation when starting the gas turbine, the dust concentration in the exhaust gas in at least the bypass passage outlet side 0.1 g ^/ m 3 (Normal) or less, preferably became 0.05 g ^/ m 3 (Normal) or less When you quit,
(3) measuring the dust concentration at least on the outlet side of the bypass path of the exhaust gas path;
(4) After the operation at the time of startup of the gas turbine is finished, guiding the exhaust gas to the main path using the flow path switching damper
(5) The filter-type dust collector may have a dust collection rate (colorimetry) of 60% or more and / or a particle size of 50 μm or less.
(6) A dust concentration meter is disposed at least on the outlet side of the bypass path of the exhaust gas path,
It is considered that adopting can be a more preferable solution.

  According to the present invention according to the above-described configuration, dust (flaky matter) contained in exhaust gas expected to be generated particularly at startup when operating a gas turbine, for example, a gas turbine having exhaust heat recovery equipment Removal of harmful dust into the atmosphere by removing dust from the exhaust gas path with a filter-type dust collector, which is disposed in the bypass path used at startup, among others. it can. Furthermore, since the exhaust gas can be dissipated without passing through the filter-type dust collector when the start-up operation is finished and the normal (stable) operation is achieved, unnecessary pressure loss is avoided and effective energy recovery is realized. There is an effect that it can be done, and the improvement of power generation efficiency can be aimed at.

It is a schematic diagram of the equipment flow for describing one embodiment of the present invention. It is a schematic diagram of the equipment flow for describing other embodiments of the present invention.

  FIG. 1 shows an example of a turbine suitable for use in the present invention, in particular, a gas turbine installation that generates electric power by using a by-product gas such as blast furnace gas as a fuel gas. In this figure, 1 in the figure is a gas turbine, 2 is a compressor that compresses air taken from the outside, 3 is a combustor that obtains high-temperature and high-pressure gas by mixing compressed air with fuel gas and burning it. In general, the gas turbine 1 is rotated by the high-temperature, high-pressure gas thus obtained, and a generator (not shown) mounted coaxially mainly with the rotation shaft is activated to generate electric power. is there.

  In the example shown in FIG. 1, an exhaust heat recovery boiler 4 for recovering sensible heat of exhaust gas is disposed on the downstream side (exhaust outlet side) of the turbine 1 and generated by the exhaust heat recovery boiler 4 It is an example which arranges a steam turbine 5 to be driven by steam and generates a power by starting a generator through the steam turbine 5. In addition, 6 of illustration is a condenser.

  In the above-mentioned turbine equipment, in the present invention, the exhaust gas path 7 is configured and arranged directly downstream of the gas turbine 1 or indirectly via the exhaust heat recovery boiler 4 etc. In particular, it prepared for operation at the time of gas turbine start-up.

  Specifically, the flow path switching damper 8 is disposed in the exhaust gas path 7, and the extension position thereof is a main path 7a used during normal operation and a bypass path 7b used for startup operation. The bypass path 7b is used only for a predetermined time during start-up operation of the gas turbine.

And in this invention, in order to use it at the time of start-up operation of a gas turbine, the filter type dust collector 9 is arrange | positioned in the said bypass path 7b. As the filter dust collector 9, layered 1 plurality of exhaust gas temperature (usually 100 to 150 ° C.) the resistance heat Eyafiruta considering (medium wire mesh with supported glass cotton ones box shape using the as) It is preferable to use them in a row at a required interval.

  By using such a filter-type dust collector 9, dust contained in high-temperature exhaust gas on the outlet side of the so-called gas turbine 1 or exhaust heat recovery boiler 4 which is often observed particularly at the start of the gas turbine It is possible to remove flakes consisting of iron dust generated on the inner surface of the boiler tube or flakes of attached sulfuric acid or the like generated on the inner surface of the boiler tube as described above, and exhaust gas may be dissipated as it is. It is possible to reduce the amount of dust and the like in the environment to such an extent that there is no problem at all.

  As the performance of the filter-type dust collector 9 meeting such requirements, for example, in order to make the flakes have a particle diameter equal to or less than the visible particle diameter, the average collection rate by the colorimetric method is as defined in JIS 9908. It is preferable to adjust the number of heat-resistant air filters installed so that the performance becomes 60% or more and / or the size of particles passing through the filter is 50 μm or less (however, the heat resistance with an average collection rate of 60% or more) If it is an air filter, it is possible to remove up to 99.9 mass% of the incoming dust even with one unit). The reason is that the above dust collection rate, filter passing particles can overcome environmental problems.

  In the present invention, it is preferable that the operation at the time of gas turbine start-up be completed until at least 6 hours have passed, which is about 4 to 5 hours after the start of start-up. The reason is that when the waste heat recovery boiler 4 inside is washed with water in a real machine, the water inside the boiler 4 after washing is dried by the exhaust gas at the time of start-up, and at least 6 hours after start-up, generation of new dust Because there is no

Also, the operation of the startup gas turbine, at least dust concentration 0.1 g ^/ m 3 in the exhaust gas at the outlet side of the bypass passage 7b (Normal) or less, preferably equal to or less than 0.05g ^/ m 3 (Normal) It is desirable to end when you The reason is that, in the actual machine, if it is reduced to 0.05 g / m ³ (Normal) or less, no further increase in dust is observed. This level corresponds to a dust scattering amount of about 1 kg / min in a 150 MW class gas turbine (described in the example) to be described below. The situation where 1 kg of dust is detached and scattered from the boiler per minute is assumed to be unsteady, and it is desirable to switch the route after confirming that the dust concentration has become lower than this level. .

  In addition, about the said filter-type dust collector 9, if trapping dust to a fixed quantity, replacement | exchange is needed. Therefore, when the number of the heat-resistant air filters is increased and the dust collection area is increased, the life of the filters can be extended and the replacement cycle becomes longer. On the other hand, if the number of filters is increased, the initial investment is increased, so it is necessary to select the optimum number. Since the heat-resistant air filter is used only for several hours (for example, about 5 hours) at the start of the facility and becomes standby (not used) after use, the number of gas turbines with a large number of starts increases the number of filters. In a gas turbine having a small number of start-up times, it is preferable to reduce the number of filters. Generally, in the case of a gas turbine having about 10 times of start / stop times a year, a filter of heat-resistant air is used for 50 hours a year. The filter capacity may be selected so as to be more than time. The number of such filters is sufficient for the construction cost compared to the maintenance and operation costs of the power plant.

  FIG. 2 shows an integrated coal gasification combined cycle power generation system (IGCC installation) which is one of the examples applicable to the present invention. In this example, in the gas turbine 1, the high pressure coal gasification fuel gas generated from the coal gasifier 12 with a gas purification device is burned in the combustor 3 using the air compressed by the air compressor 2, Using the sensible heat of the high temperature exhaust gas, the steam turbine 5 recovers the power generation energy using the steam generated by the exhaust heat recovery boiler 4.

  And, in order to prevent the dust and flakes generated in the exhaust heat recovery boiler 4 and the like from flowing out when starting up the gas turbine equipment using this equipment, the flow path switching installed in the exhaust gas path 7 The damper 8 was switched (in this case, closed), and the exhaust gas was allowed to flow through the filter type dust collector 9 of the bypass path 7 b to remove dust for a fixed time (5 hours). Then, sufficient dust removal is performed as described below, and at the stage where dust generation has decreased (after 5 hours), the flow switching damper 8 is opened to complete the bypass operation of the exhaust gas, and the main path 7a Switched to.

That is, in the gas turbine equipment (power generation output: 150 MW) according to the illustrated example, the amount of exhaust gas: 1,000,000 m ³ / h (Normal), exhaust gas temperature (outlet temperature of exhaust heat recovery boiler 4): 130 ° C., at startup The start-up operation was carried out under the conditions of dust concentration of 1 mg / m ³ (Normal) at the inlet side of the flow path switching damper 8 of FIG. The filter dust collector installed in the bypass path 7b has 200 heat resistant 250 ° C. heat-resistant filters (the dust collection rate is 60% of the average collection rate in the colorimetry method) made by Shinwa Tech. Stage). Under this condition, after 5 hours of start-up operation, the dust concentration at the outlet (chimney 10) side of the exhaust gas passage contains substantially less than 0.01 mg / m ³ (Normal). Not able to exhaust gas.

  The method of start-up operation of the gas turbine according to the present invention and the exhaust gas path device of the gas turbine are mainly dust in the exhaust gas on the outlet side of the various types of gas turbine equipment in the embodiments, as well as various types of gas turbines. It is applicable to all turbine equipment in the case where it contains and flakes.

Reference Signs List 1 gas turbine 2 compressor 3 combustor 4 exhaust heat recovery boiler 5 steam turbine 7 exhaust gas passage 7a main passage 7b bypass passage 8 damper for flow passage switching 9 filter type dust collector 10 chimney 11, 11 'dust concentration meter 12 coal gasification Furnace G generator

Claims (8)

In the operation at the start of the gas turbine which burns fuel gas and obtains driving force, the exhaust gas path of this gas turbine is branched into the main path and the bypass path which can switch the flow path through the flow path switching damper During operation at the time of gas turbine startup, exhaust gas is introduced into the bypass path, and the exhaust gas is removed by a filter-type dust collector using a heat-resistant air filter disposed in the path. After completion of the dust removal operation, the exhaust gas is introduced to the main path.   The operation method at the time of gas turbine startup according to claim 1, wherein the operation at the time of gas turbine startup is ended until six hours have elapsed after the start of startup. The operation at the time of gas turbine startup is terminated when the concentration of dust in the exhaust gas at least on the outlet side of the bypass path is 0.1 g / m ³ (Normal) or less. The operating method at the time of gas turbine start-up described.   The method for operating a gas turbine according to any one of claims 1 to 3, wherein the measurement of the dust concentration in the exhaust gas path is performed on the inlet side and the outlet side of the bypass path. The filter-type dust collector using the heat-resistant air filter is prepared by adjusting the number of filters installed so that the dust collection rate (colorimetric method) can be 60% or more and / or the size of filtration passing particles can be 50 μm or less The operating method at the time of gas turbine starting according to any one of claims 1 to 4, characterized in that In an exhaust gas path device of a gas turbine which obtains a driving force by burning a fuel gas, the exhaust gas path is branched into a main path and a bypass path whose flow paths can be switched using a flow path switching damper. A filter-type dust collector using a heat-resistant air filter for start-up operation is disposed in the bypass path, and a bypass path downstream of the filter-type dust collector is connected to a main path. . The filter-type dust collector using the heat-resistant air filter is prepared by adjusting the number of filters installed so that the dust collection rate (colorimetric method) can be 60% or more and / or the size of filtration passing particles can be 50 μm or less The exhaust gas path device of a gas turbine according to claim 6, characterized in that   8. The exhaust gas passage device for a gas turbine according to claim 6, wherein a dust densitometer is disposed at least on the outlet side of the bypass passage of the exhaust gas passage.

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