JP2017166334A - Operation method in starting gas turbine, and exhaust gas passage device of gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of solving a problem on scattering of dust and various flakes which may generate in starting a turbine, in advance.SOLUTION: In an operation method in starting a gas turbine, and an exhaust gas passage device applying the operation method in starting the gas turbine, an exhaust gas passage of the gas turbine is branched into a main passage and a bypass passage capable of switching a flow channel through a flow channel switching damper in the operation in starting the gas turbine, and the exhaust gas is guided into the bypass passage to remove dust in the exhaust gas by a filter-type dust collector during the operation in starting the gas turbine.SELECTED DRAWING: Figure 1

Description

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

  In general, 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 electric power is generated by a generator that uses the rotational force. In this case, combustion gas or the like is directly introduced into the turbine, but these fuel gas, combustion air, and the like are usually cleaned by using a filter or the like on the inlet side of the turbine. That is, in the case of a gas turbine, conventionally, the upstream side (incoming side) fuel gas or the like is introduced after being cleaned. As a result, the amount of dust in the exhaust system combustion gas which is the downstream side of the gas turbine, that is, 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 the exhaust gas is usually not reprocessed or stopped to the extent that a denitration facility is provided.

  As another conventional technique, a combined cycle power generation in which an exhaust heat recovery boiler is disposed downstream of the gas turbine, high temperature steam is generated by the exhaust heat recovery boiler, and heat recovery is performed by the steam turbine. There is also a coal gasification combined power generation system in which a cyclone and a gas purification device are arranged on the upstream side (Patent Document 1).

  Furthermore, in the gas turbine disclosed in Patent Document 2, a dust removal filter is disposed on the upstream side (entrance side) of the turbine so that air containing no dust is sent to the compressor.

JP 2011-214562 A JP 2011-140880 A

  As described above, in the case of the conventional gas turbines disclosed in Patent Documents 1 and 2 and the like, after the pressure and sensible heat of the combustion gas are recovered, the exhaust gas is generally directly discharged into the atmosphere as an exhaust gas through a chimney or the like. Is normal.

  By the way, the existing gas turbine is used after the combustion air is previously dust-removed by a filter on the inlet side of the turbine, so that 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. Therefore, in this case, it can be said that there is no problem even if the exhaust gas is diffused as it is. However, the operation of a gas turbine may be stopped for inspection or equipment repair. At such timing, air flows into the passage through which the combustion gas (exhaust gas) flows, and iron rust or the like may be generated due to temperature change or inflow of moisture.

  In addition, especially in combined cycle power generation using coal-containing gas such as coal gasification gas and blast furnace gas, and fuel containing sulfur content such as heavy oil, in the exhaust heat recovery boiler immediately after the gas turbine, Since the contained sulfur is oxidized to produce SOx, it reacts with moisture in the combustion gas to produce sulfuric acid, which reacts with the boiler tube to produce iron sulfate on the inner surface of the boiler tube. is there.

Furthermore, when operating the gas turbine, denitration ammonia may be used to reduce NOx contained in the exhaust gas. In this case, ammonium sulfate (NH _{4) is} produced by the reaction between the denitration ammonia and SOx. ) ₂ SO ₄ is generated, and it is inevitable that this will adhere to and accumulate on the inner surface of the boiler tube of the exhaust heat recovery boiler.

  In this way, in a gas turbine that contains sulfur in the fuel and has an exhaust heat recovery facility, products such as iron sulfate and ammonium sulfate are inevitably generated and adhered to the inner surface of the boiler tube by using the exhaust heat recovery facility. It is thought to be growing.

  In this regard, when the gas turbine is operating in a steady state, the sulfur oxidation product reacted on the boiler tube surface as described above is in a state of being attached to the surface of the boiler tube. There will be no exhaust from the chimney with the combustion gas. However, as described above, when the facility is stopped such as inspection or repair of the facility, the temperature of the boiler tube is lowered. Therefore, products such as iron rust, iron sulfate, and ammonium sulfate that have adhered may peel off due to heat shrinkage of the boiler tube at this time, resulting in flakes. In such a case, after that, when the equipment (gas turbine) is started up, the iron rust, iron sulfate, and ammonium sulfate are peeled off and flakes are mixed into the exhaust gas, which is scattered from the chimney. There was a risk. Since such iron rust, iron sulfate, and ammonium sulfate are diffused as dust, there is a risk of causing an undesirable situation in the environment.

  On the other hand, since such a problem does not occur at the time of normal facility operation, it is necessary to pay attention to the above-described problem only at the time of facility start-up operation. Therefore, conventionally, in order to prevent dust discharged from the chimney from being scattered as much as possible when the turbine is started, it is often necessary to start up only when the weather conditions are good, or regularly clean the inside of the boiler. It is.

  An object of the present invention is to provide a technique that can solve the problem of dust and various flakes that may occur when starting such a turbine.

  The inventors have overcome the above-mentioned problems of the prior art, and, as a result of earnestly and intensively studying the achievement of the object, 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 exhaust gas path of the gas turbine can be switched to the main path through the path switching damper. Branching into a bypass path, and during operation when starting the gas turbine, exhaust gas is guided into the bypass path, and the exhaust gas is removed by a filter dust collector disposed in the path. It is the operation method at the time of starting the gas turbine.

  The present invention also provides an exhaust gas path device for a gas turbine that obtains a driving force by burning fuel gas as an operation method at the time of starting the gas turbine. An exhaust gas path device for a gas turbine characterized in that a filter type dust collector for start-up operation is disposed in the bypass path, and the main path and the bypass path are switchable using Propose.

In the present invention,
(1) The operation at the time of starting up the gas turbine should be terminated by 6 hours after the start of starting,
(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 Sometimes ending,
(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 starting the gas turbine is completed, the exhaust gas is guided to the main path using the flow path switching damper.
(5) The filter-type dust collector should have a dust collection rate (colorimetric method) of 60% or more and / or a filter-passing 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 the above can be a more preferable solution.

  According to the present invention having the above-described configuration, when operating a gas turbine, for example, a gas turbine having an exhaust heat recovery facility, dust contained in exhaust gas that is expected to be generated at the start-up (flaky state) By removing the dust (including dust) with a filter-type dust collector installed in the exhaust gas path, especially the bypass path used at startup, it is possible to prevent harmful dust from being released into the atmosphere. it can. Furthermore, when the start-up operation is completed and normal (stable) operation is reached, exhaust gas can be dissipated without passing through a filter type dust collector, so that effective pressure recovery can be achieved by avoiding unnecessary pressure loss. There is an effect that it can be performed, and power generation efficiency can be improved.

It is an approximate line figure of the equipment flow for explaining one embodiment of the present invention. It is an approximate line figure of the equipment flow for explaining 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 facility that generates electric power using a by-product gas such as a blast furnace gas as a fuel gas. In this figure, 1 is a gas turbine, 2 is a compressor that compresses air taken in from the outside, and 3 is a combustor that obtains high-temperature and high-pressure gas by mixing the compressed air with fuel gas and burning it. In general, the gas turbine 1 is rotated with the obtained high-temperature and high-pressure gas, and a generator (not shown) mounted coaxially with the rotating shaft is started to generate 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 downstream of the turbine 1 (exhaust output side), and is generated in the exhaust heat recovery boiler 4. This is an example in which a steam turbine 5 driven by steam is disposed, and a generator is activated via the steam turbine 5 to generate power. In addition, 6 of illustration is a condenser.

  In the turbine equipment, in the present invention, the exhaust gas path 7 is configured and arranged directly on the downstream side of the gas turbine 1 or indirectly through the exhaust heat recovery boiler 4 or the like, that is, as follows. In particular, it was prepared for operation when the gas turbine was started.

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

  In the present invention, a filter type dust collector 9 is disposed in the bypass path 7b in order to use the gas turbine for starting operation. As the filter type dust collector 8, one or more such as a known heat-resistant air filter (a box shape using glass cotton supported by a metal mesh as a filter medium) considering exhaust gas temperature (usually 100 to 150 ° C.) is used. It is preferable to use them by stacking them or arranging them at a required interval.

  By using such a filter type dust collector 9, the dust contained in the high-temperature exhaust gas at the outlet side of the so-called gas turbine 1 or exhaust heat recovery boiler 4, which is often observed especially at the start of the gas turbine ( Flakes made of iron sulfate pieces generated on the inner surface of the boiler tube or the peeled pieces of adhering sulfuric acid, etc., can be removed. The dust inside can be reduced to an extent that does not cause any problems in the environment.

  As the performance of the filter type dust collector 9 that can meet such a demand, for example, in order to make the flakes have a visible particle size or less, the average collection rate in the colorimetric method defined in JIS 9908 is the dust collection rate. It is preferable to adjust the number of heat-resistant air filters installed so that the size is 60% or more and / or the size of the filtration-passed particles is 50 μm or less (however, the heat-resistance with an average collection rate of 60% or more) If it is an air filter, removal of up to 99.9 mass% of the incoming dust is possible. This is because the above-mentioned dust collection rate and filtered particles can overcome environmental problems.

  In the present invention, the operation at the time of starting the gas turbine is preferably finished by at least 6 to 5 hours after the start of starting. The reason for this is that when the inside of the exhaust heat recovery boiler 4 is washed with water in the actual machine, the moisture inside the boiler 4 after washing is dried by the exhaust gas at the start, and at least 6 hours after the start, new dust is generated. Because there will be no more.

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. The reason for this is that in the actual machine, when it is reduced to 0.05 g / m ³ (Normal) or less, the subsequent increase in dust is not observed. This level corresponds to a dust scattering amount of about 1 kg / min in a 150 MW class gas turbine (assumed in the embodiment) described below. The situation where 1 kg of dust is separated from the boiler per minute and scattered is assumed to be an unsteady state, and it is desirable to switch the route after confirming that the dust concentration is below this level. .

  In addition, about the said filter type dust collector 9, if dust is captured to a fixed quantity, replacement | exchange will be needed. Therefore, increasing the number of heat-resistant air filters and increasing the dust collection area can prolong the life of the filter and increase the replacement period. On the other hand, since the initial investment increases when the number of filters is increased, it is necessary to select the optimum number. The heat-resistant air filter is used only for a few hours (for example, about 5 hours) at the time of starting the equipment, and is in a standby state (not used) after use. Therefore, a gas turbine having a large number of start-ups increases the number of the filters, It is preferable to reduce the number of filters in a gas turbine with a small number of startups. In general, in the case of a gas turbine having the number of start / stop operations of about 10 times a year, since a heat-resistant air filter is used for 50 hours per year, it is generally used for 2 years, which is a regular maintenance span of the gas turbine. What is necessary is just to select so that it may become filter capacity more than time. Such a number of filters is a sufficiently reasonable construction cost compared to the power plant maintenance and operation costs.

  FIG. 2 shows an integrated coal gasification combined power generation system (IGCC facility) which is one of the examples suitable for the present invention. In this example, in the gas turbine 1, while the high-pressure coal gasification fuel gas generated from the coal gasification furnace 12 with the gas purifier is burned in the combustor 3 using the air compressed by the air compressor 2, Power generation energy is recovered by the steam turbine 5 using steam generated by the exhaust heat recovery boiler 4 using the sensible heat of the high-temperature exhaust gas.

  In starting operation of the gas turbine equipment using this equipment, in order to prevent the dust and flakes generated in the exhaust heat recovery boiler 4 and the like from flowing out, the flow path switching installed in the exhaust gas passage 7 is used. The damper 8 was switched (in this case, closed), exhaust gas was passed through the filter type dust collector 9 in the bypass path 7b, and dust was removed for a fixed time (5 hours). Then, when sufficient dust removal is performed as described below and dust generation is reduced (after 5 hours), the flow switching damper 8 is opened, exhaust gas bypass operation is completed, and the main path 7a Was switched to.

That is, in the gas turbine facility (power generation output: 150 MW) according to the illustrated example, the exhaust gas amount: 1 million m ³ / h (Normal), the exhaust gas temperature (the outlet temperature of the exhaust heat recovery boiler 4): 130 ° C., at the time of startup The start-up operation was performed under the condition of the dust concentration on the inlet side of the flow path switching damper 8 of 1 mg / m ³ (Normal). The filter dust collector installed in the bypass path 7b is installed in parallel with 200 Shinwa Tech heat-resistant 250 ° C heat-resistant filters (the dust collection rate is 60% in terms of the average collection rate by the colorimetric method). Step). Under this condition, after 5 hours of start-up operation, the concentration of dust on the outlet (chimney 10) side of the exhaust gas path substantially contains 0.01 mg / m ³ (Normal) or less. No gas could be exhausted.

  The gas turbine start-up operation method and the gas turbine exhaust gas path apparatus according to the present invention mainly include dust in the exhaust gas on the outlet side in various uniaxial and biaxial turbines in addition to various gas turbine equipment in the embodiments. It can be applied to all turbine equipments that contain flakes and flakes.

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Compressor 3 Combustor 4 Exhaust heat recovery boiler 5 Steam turbine 7 Exhaust gas path 7a Main path 7b Bypass path 8 Channel switching damper 9 Filter dust collector 10 Chimney 11, 11 'Dust concentration meter 12 Coal gasification Furnace G Generator

Claims (8)

  When starting a gas turbine that obtains driving force by burning fuel gas, the exhaust gas path of this gas turbine is branched into a main path and a bypass path that can switch the flow path via a flow path switching damper During the operation at the time of starting the gas turbine, the exhaust gas is guided into the bypass path, and the exhaust gas is removed by a filter type dust collector disposed in the path. how to drive.   The operation method at the time of gas turbine start-up according to claim 1, wherein the operation at the time of gas turbine start-up is terminated by 6 hours after the start of start-up. The operation at the time of starting the gas turbine is terminated when the concentration of dust in the exhaust gas at least on the outlet side of the bypass path becomes 0.1 g / m ³ (Normal) or less. The operation method at the time of gas turbine starting of description.   The method for operating a gas turbine according to any one of claims 1 to 3, wherein the dust concentration is measured at least on the outlet side of the bypass path of the exhaust gas path.   5. The exhaust gas is guided to a main path by using the flow path switching damper after the operation for dust removal at the time of starting the gas turbine is completed. Operation method at the time of gas turbine startup.   In an exhaust gas path device of a gas turbine that obtains driving force by burning fuel gas, the exhaust gas path is branched into a main path and a bypass path that can be switched using a flow path switching damper. An exhaust gas path device for a gas turbine, characterized in that a filter type dust collector for starting operation is disposed in the bypass path.   7. The gas turbine according to claim 6, wherein the filter type dust collector uses a dust collection rate (colorimetric method) of 60% or more and / or a size of filtration-passed particles of 50 μm or less. Exhaust gas path device.   The exhaust gas path device for a gas turbine according to claim 6 or 7, wherein a dust concentration meter is disposed at least on the outlet side of the bypass path of the exhaust gas path.

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