JP2007170245A - Gas turbine facility, low calory gas feeding facility, and method of suppressing rise of calory of gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low calory gas feeding facility capable of stably feeding a low calory gas as a gas turbine fuel while suppressing the abrupt rise of the calory of the gas. <P>SOLUTION: This gas turbine facility comprises a low calory gas feed pipe 3 for feeding the low calory gas to a gas turbine 2, a steam feed pipe 4 for feeding steam into the low calory gas feed pipe 3, a mixer 6 disposed at the connection part between the low calory gas feed pipe 3 and the steam feed pipe 4, a calorimeter 11 disposed in the low calory gas feed pipe 3 and detecting the heating value of the gas, and a control device 100. The control device 100 feeds the steam from the steam feed pipe 4 when the value detected by the calorimeter 11 exceeds a reference value to controllably suppress the rise of the calory of the low calory gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas turbine facility, a low calorie gas supply facility, and a method for suppressing the calorie rise of the gas. More specifically, a low calorie gas supply facility that supplies a low-calorie gas to the gas turbine in a state where it can be used as a fuel for the gas turbine, a gas turbine facility equipped with the low-calorie gas supply facility, and heat generation of the low calorie gas for the gas turbine fuel The present invention relates to a method for suppressing an increase in amount.

In the steelmaking field, for example, when pig iron is produced by the blast furnace method, a top gas (Blast Furnace Gas, hereinafter referred to as BFG) is generated as a by-product gas from the blast furnace. Since the total calorific value of BFG reaches about half of the calorific value of the coke used, BFG is widely used in steelworks to reduce the cost of ironmaking. BFG generates 3000 Nm ³ per ton of input coke, and its composition is 10 to 18% CO ₂ , 22 to 30% CO, 52 to 60% N ₂ , 0.5 to 4% H ₂ , CH ₄ Is 0.5 to 3%.

BFG contains 2-10 g / Nm ³ of dust in addition to this. After removing this to about 0.01 g / Nm ³ with a dust remover, hot air is used as a low calorie fuel gas with a calorific value of about 800 kcal / Nm ^3. Used in furnaces, coke ovens, heating furnaces, boilers, etc. In recent years, gas turbines can also be burned with low calorie gas due to improvements in technology, and the number of cases in which BFG is used as gas turbine fuel is increasing.

  On the other hand, in recent years, new iron-making processes other than the blast furnace method (for example, direct reduced iron method) are being developed, and combustion methods that can be applied to the effective use of by-product gas that constantly fluctuates in calories from such new processes. Development is awaited. In any steelmaking process, the characteristics (gas composition and calorie) of the by-product gas generated vary depending on the equipment and operation contents. Even in the same equipment, it changes from time to time according to the characteristics of each raw material and the reaction process. There is no constant.

  Looking at calorie, which is the most important characteristic when using byproduct gas as gas turbine fuel, the upper limit of the allowable fluctuation range of calorie inherent to each gas turbine (for example, about + 10% of the average calorie value) When it exceeds, that is, when the calorie value suddenly increases, the combustion temperature in the combustor of the gas turbine may suddenly become an abnormally high temperature. As a result, the burner part, the stationary blades and the moving blades of the turbine are damaged and the life is shortened, and the economical continuous operation of the gas turbine equipment becomes difficult.

A technique of diluting with nitrogen gas (N ₂ ) in order to suppress calorie fluctuation of by-product gas is known (see, for example, Patent Document 1 and Patent Document 2). However, when the by-product gas is diluted only with N ₂ , a large amount of expensive inert gas such as N ₂ is inevitably used depending on the variation value of calories. Moreover, it is very difficult to secure a large amount of inert gas continuously except for a special industrial field. Furthermore, it is necessary to extend a large amount of inert gas storage facilities and various equipment facilities for supplying gas including piping. For these reasons, the method of using an inert gas lowers the economics of gas turbine power generation and hinders the technical superiority of the gas turbine that advocates high efficiency.
JP 2002-155762 A JP 9-317499 A

  The present invention has been made to solve such a problem, and has a low calorie gas supply facility capable of alleviating an increase in calorie of a low calorie fuel gas for a gas turbine, which is low in equipment cost and operation cost, and the low calorie gas supply. It aims at providing the gas turbine equipment provided with the equipment, and the method of suppressing the rise in calories of low calorie gas for gas turbine fuel.

For the above purpose, the low calorie gas supply facility of the present invention is:
A low caloric gas supply passage for supplying low caloric gas as fuel gas to the gas turbine;
A water vapor supply passage connected to the low calorie gas supply passage for supplying the water vapor for dilution to the low calorie gas supply passage;
A calorific value detection device for detecting a calorific value in the gas disposed in the low calorie gas supply passage;
And a control device capable of controlling the water vapor supply operation by the water vapor supply passage based on the detection result of the calorific value detection device.

  According to this invention, the calorie rise of the low calorie gas which continuously fluctuates in calorie can be suppressed by mixing the water vapor that does not contain the combustible gas and is easily procured to dilute the low calorie gas. Here, the calorific value detection device includes not only a device that directly measures the calorific value of gas (for example, a so-called calorimeter) but also a device that measures the content of combustible components in the gas.

  The control device is configured to set the maximum allowable calorie value of the fuel gas of the gas turbine and to supply water vapor from the water vapor supply passage so as to maintain the caloric value of the low calorie gas below the maximum allowable caloric value. be able to.

In the low calorie gas supply facility in which the fuel compressor and the cooler are installed up to the combustor of the gas turbine in the low calorie gas supply passage,
A mixer for mixing the low calorie gas and water vapor can be installed between the fuel compressor and the cooler. This is because the water vapor is mixed at a position where low calorie gas having a pressure and temperature suitable for the pressure and temperature of the water vapor to be supplied flows. Note that steam is not directly supplied to the combustor.

  In each of the above facilities, a first tank for temporarily storing low calorie gas is disposed in the low calorie gas supply passage, and the first tank has an inlet and an outlet. It is preferable that the upstream side of the calorie gas supply passage is connected, and the downstream side of the low calorie gas supply passage is connected to the outlet. All of the low-calorie gas supplied through the low-calorie gas supply passage is temporarily stored in the first tank and mixed therein, thereby reducing the width of the calorie fluctuation and reducing the calorie fluctuation speed. Therefore, calorie leveling control by steam dilution at the downstream portion of the first tank outlet is further facilitated. The calorific value detection device described above is installed in the low calorie gas supply passage, but in a facility in which the first tank or the second tank described later is installed in the low calorie gas supply passage, this tank also constitutes the low calorie gas supply passage. Therefore, it also includes attaching the calorific value detection device to the tank.

  A second tank for temporarily storing the low calorie gas is disposed in the low calorie gas supply passage, and the low calorie gas is supplied from the low calorie gas supply passage to the second tank between the low calorie gas supply passage and the second tank. A gas inlet passage for feeding the gas into the tank, and an outlet passage for returning the low calorie gas from the second tank to the low calorie gas supply passage, and the first gas pressure feeding device for feeding the low calorie gas toward the second tank through the inlet passage Is preferably a low-calorie gas supply facility. This is because the same action as that of the first tank is achieved.

A return passage for returning a part of the low calorie gas to be supplied to the upstream side of the low calorie gas supply passage is disposed in the low calorie gas supply passage, and the low calorie gas is provided upstream of the low calorie gas supply passage in the return passage. A low-calorie gas supply facility in which a second gas pumping device for pumping toward is provided is preferable. This is because the same action as the action by the first tank is achieved. The steam shut-off device that is disposed in the steam supply passage and can shut off and open the passage, and is disposed on the upstream side of the steam shut-off device. A low calorie gas supply facility equipped with a water vapor release device is preferred. As the water vapor shut-off device, for example, a stop valve or a flow control valve can be employed.

  As the water vapor for dilution, water vapor generated by a boiler that uses exhaust heat from the gas turbine to which the low calorie gas supply facility supplies fuel can be used. In addition, the direct use of the steam generated from the boiler includes the use of the steam as dilution steam after being used in a steam turbine for power generation.

The gas turbine equipment of the present invention is
A gas turbine and a low-calorie gas supply facility for supplying low-calorie gas as fuel gas to the gas turbine are provided, and the low-calorie gas supply facility is any one of the low-calorie gas supply facilities described above.

In such gas turbine equipment, a plurality of gas turbines are installed, and each gas turbine is provided with the low-calorie gas supply equipment and the exhaust heat recovery boiler and / or auxiliary boiler,
The steam introduced into the steam supply passage of the low calorie gas supply facility may be steam generated by an exhaust heat recovery boiler and / or an auxiliary boiler installed in a gas turbine other than the corresponding gas turbine.

The low calorie gas calorie increase suppressing method for gas turbine fuel of the present invention is:
A calorie measuring step for measuring the calorific value of the low calorie gas supplied to the gas turbine as fuel gas;
A water vapor mixing step of mixing dilution water vapor into the low calorie gas so that the measurement result does not exceed the set allowable caloric value.

  According to the present invention, a facility for supplying a gas turbine with a low calorie gas that can fluctuate in calorie, such as a process by-product gas, is realized with a low facility cost and an operation cost. This is because water vapor containing no combustible component can be obtained easily and in large quantities in order to suppress the caloric rise of low calorie gas that can be used as fuel gas.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a low calorie gas supply facility of the present invention, a gas turbine facility including the same, and a method for suppressing an increase in the calorific value of low calorie gas for gas turbine fuel will be described with reference to the accompanying drawings.

  FIG. 1 is a piping diagram showing an outline of a gas turbine facility including a low calorie gas supply facility 1 according to an embodiment of the present invention. A gas turbine power generation facility is exemplified as the gas turbine facility.

This low calorie gas supply facility 1 is for diluting the low calorie gas, and a low calorie gas supply pipe 3 for supplying by-product gas (hereinafter referred to as low calorie gas) generated directly in the reduced iron facility S to the gas turbine 2 as fuel. And a water vapor supply pipe 4 for supplying water vapor to the low calorie gas supply pipe 3. The reason why water vapor is mixed in order to dilute the low calorie gas and suppress the rise in calorie is because the water vapor does not contain combustible gas or oxygen gas. Here, low calorie gas is defined as a gas whose calorific value is about 12 MJ / Nm ³ or less.

  A control device 100 for controlling the operation of the low calorie gas supply facility 1 is provided.

  The low calorie gas supply pipe 3 includes a dust collector 9 for removing dust from the low calorie gas directly sent from the low calorie gas generating source of the reduced iron facility S, and a buffer tank 10 for primarily storing the low calorie gas. is set up. The buffer tank 10 has a relatively large capacity, and the low calorie gas flowing in while calorimetrically changing is mixed inside the buffer tank 10. The effect will be described later. On the downstream side of the buffer tank 10, a calorific value detection device 11 for detecting the calorific value of the low calorie gas and a flow meter 12 for measuring the flow rate are installed.

  Here, as the calorific value detection device 11, a so-called calorimeter that directly measures the calorific value of gas, a device that measures the content (concentration) of combustible components, and the like are used. The heat generation amount detection device 11 can be directly attached to the buffer tank 10. In addition to the calorific value detection device 11 on the low calorie gas supply pipe 3, another calorific value detection device may be attached to the buffer tank 10. When importance is attached to the detection speed, it is preferable to use a combustible gas concentration detector at present. Furthermore, depending on the type of combustible component contained in the low calorie gas applied, and depending on the combustible component in which the main concentration fluctuation occurs (for example, carbon monoxide in the by-product gas in the direct reduced iron method), the component You may use the density | concentration detector which detects this density | concentration. In this specification, these calorific value detection devices as a whole are referred to as “calorimeters”.

  A low pressure fuel gas compressor (hereinafter referred to as a low pressure compressor) 16 and a high pressure fuel gas compressor (hereinafter referred to as a high pressure compressor) 17 of the gas turbine 2 are installed on the downstream side of the flow meter 12 in that order. A cooler 18 is disposed between the compressors 16 and 17 for cooling the mixed gas that is a fuel gas. The low-pressure compressor 16 and the high-pressure compressor 17 in the present embodiment are of a type that is integrally driven by a motor 15 after being connected coaxially. The fuel compressor is not limited to two high and low stages as in the present embodiment, and may be a single stage or three or more stages.

  A mixer 6 is installed between the low-pressure compressor 16 and the cooler 18. The water vapor supply pipe 4 described above is connected to the mixer 6 where the water vapor for dilution is mixed with the low calorie gas. Since the portion of the low calorie gas supply pipe 3 downstream from the mixer 6 is sometimes sent to the gas turbine 2 in a state where the low calorie gas is mixed with water vapor, the pipe in this range is referred to as a mixed gas supply pipe 13. A calorimeter 14 is installed in the mixed gas supply pipe 13.

  A low calorie gas supply pipe 13 between the high pressure compressor 17 and the combustor 19 of the gas turbine 2 is provided with a flow rate adjusting valve (hereinafter referred to as a flow control valve) 20 for adjusting the turbine output. Reference numeral 21 denotes a filter installed in a pipe for supplying air to the combustor 19. A generator 22 is connected to the gas turbine 2.

  In FIG. 1, both compressors 16 and 17 are not coaxially connected to the turbine 2 and are configured in a multi-shaft type that is driven by a dedicated motor after both 16 and 17 are coaxially connected. It is not limited to this. For example, the compressors 16 and 17 may be uniaxially connected to the turbine 2 coaxially and driven to rotate by the turbine 2.

  In this gas turbine power generation facility, an exhaust heat recovery boiler 51 using the heat of exhaust gas from the gas turbine 2 is provided. The steam obtained by the exhaust heat recovery boiler 51 can be sent to the user point U as process steam or the like, but instead of this or with this, a steam turbine 52 for generating electricity with the steam is installed. May be. The exhaust gas from the exhaust heat recovery boiler 51 is dissipated into the atmosphere through a chimney (not shown). Reference numeral 54 denotes a generator.

  Further, the steam used in the steam turbine 52 is also used to dilute the low calorie gas that is the fuel of the gas turbine 2 as follows. FIG. 1 shows a back-pressure steam turbine. Steam after being used in all stages is sent to the following steam supply pipe 4 through a steam introduction pipe 53. In the case of a condensing steam turbine, the steam is extracted from the middle stage. The steam is sent to the steam supply pipe 4. This is because in the case of a condensing steam turbine, the temperature and pressure of the steam after being used in all stages is lowered.

  A water vapor supply facility for supplying water vapor to the low calorie gas will be described. A steam supply pipe 4 for supplying steam to low calorie gas is connected to the steam introduction pipe 53 for taking out the steam from the steam turbine 52 described above. A flow control valve 56 for controlling the amount of water vapor sent to the water vapor supply pipe 4 is installed in the water vapor introduction pipe 53. The water vapor supply pipe 4 is provided with a temperature reducer 23, which can cool the water vapor to an appropriate temperature for mixing with the low calorie gas. The temperature reducer 23 sprays or fountains pure water on water vapor, and a pure water supply pipe 24 is connected thereto, and a flow control valve 25 is installed in the pure water supply pipe 24. Yes. A thermometer 26 is installed on the downstream side of the temperature reducer 23. The flow control valve 25 is controlled so that the steam reaches the target temperature while feeding back the detection value of the thermometer 26.

  In the present embodiment, the water vapor supplied for dilution to the low calorie gas supply pipe 3 is generated in the exhaust heat recovery boiler 51 provided in the gas turbine 2 to which the low calorie gas supply pipe 3 supplies low calorie gas. Although it is water vapor | steam, this invention is not limited to this structure. For example, when general factory steam can be used for dilution, this steam may be used. In addition, when a steam power generation facility is installed in the vicinity, the steam of the boiler of this facility can be used after being used for power generation.

  When a plurality of gas turbine power generation facilities in which the low calorie gas supply facility 1, the gas turbine 2, the exhaust heat recovery boiler 51, and the steam turbine 52 are combined as shown in FIG. The steam of the exhaust heat recovery boiler 51 can be used for dilution. This is a case where the gas turbine is not stopped even if an emergency occurs in the steam supply source and the steam cannot be supplied. As described above, even when the steam generated in the other equipment 55 is introduced, the steam is fed into the steam supply pipe 4. Normally, a so-called auxiliary boiler is provided for cold starting such a combined power generation facility. Therefore, also in this case, the steam of the auxiliary boilers of other systems can be used for dilution.

  A stop valve 27, a flow meter 28, a flow control valve 29, and a check valve 30 are installed in that order on the downstream side of the thermometer 26 in the water vapor supply pipe 4. The water vapor supply pipe 4 is connected to a mixer 6. Between the stop valve 27 and the flow meter 28 of the water vapor supply pipe 4, a water vapor discharge pipe 31 for releasing water vapor to the atmosphere is disposed. A flow control valve 32 is installed in the water vapor discharge pipe 31.

  Next, an example of operation control of this facility by the control device 100 will be described. First, the low calorie gas is pumped toward the gas turbine 2 while monitoring the calorimeter 11 and the flow meter 12 of the low calorie gas supply pipe 3. At this time, in the water vapor supply pipe 4, the stop valve 27 is already opened and the flow control valve 29 is closed, or is opened to a predetermined opening. The flow control valve 32 of the water vapor discharge pipe 31 is in a slightly open state. Thereby, the water vapor sent from the steam turbine 52 is always released to the atmosphere from the water vapor discharge pipe 31 through a chimney (not shown). During operation, when a reference caloric value for use of the gas turbine 2 described later is set lower than an average caloric value of the supplied fuel gas, it is necessary to constantly supply water vapor to the fuel gas. The flow control valve 29 is opened to a predetermined opening as described above. When it is not necessary to set the reference calorie value of the gas turbine 2 lower than the average calorie value of the fuel gas, the flow control valve 29 is closed. The reason why the flow control valve 32 of the water vapor discharge pipe 31 is always opened is that when the supply of water vapor to the fuel gas becomes necessary or when it is desired to increase the supply amount of water vapor, the flow control valve 32 This is because the measures can be taken more quickly by adjusting the opening.

In the control device 100, an allowable calorie range for use of the fuel gas of each gas turbine 2 is set. That is, the reference calorie value (for example, 1600 kcal / Nm ³ ) and the fluctuation range (for example, ± 10% of the reference calorie value). Then, in order to prevent the caloric value of the low caloric gas from exceeding the upper limit caloric value (for example, + 10%, 1760 kcal / Nm ³ ) of the allowable fluctuation, The flow control valve 32 of the discharge pipe 31 is adjusted in the valve closing direction. In this way, water vapor is mixed with low calorie gas so that the calorie value falls within an allowable range. When supplying water vapor, the calorimeter 14 of the mixed gas supply pipe 13 is monitored together with the calorimeter 11 and the flow meter 12 in order to determine the appropriateness of the final caloric value.

  FIG. 2 shows an example of calorie control performed by mixing water vapor with low calorie gas. As shown in FIG. 2A, the allowable calorie range of the gas turbine 2 described above is lower than the calorie value of the fuel gas, that is, lower than the value estimated as the lower limit value of the calorie fluctuation of the fuel gas. Can be set to In this way, even if the calorie value of the fuel gas fluctuates, it does not fall below the allowable calorie range of the gas turbine 2, so there is no need to supply the heat increasing gas, as shown in FIG. The calorie adjustment of the fuel gas can be performed only with the steam for reducing heat.

  Moreover, the calorie control as shown in FIG. 3 may be used. That is, as shown in FIG. 3A, the allowable calorie range of the gas turbine 2 may be set so that the value estimated as the lower limit value of the fluctuating fuel gas calorie is always within the range. This is because the allowable calorie range of the gas turbine 2 is made closer to the calorie value of the fuel gas than the range shown in FIG. Then, when the fluctuating high calorie portion is about to exceed the allowable calorie range of the gas turbine 2, as shown in FIG. 3 (b), an appropriate amount of water vapor that can prevent this is supplied to reduce the calorie value. It is kept within the allowable calorie range (indicated by a broken line in FIG. 3A).

  The temperature of the low calorie gas where the mixer 6 is installed has been investigated in advance, and this temperature hardly changes. Therefore, the dilution water vapor mixed with the low calorie gas needs to be equivalent to the temperature of the low calorie gas. Therefore, as described above, the control device 100 feeds back the detection value of the thermometer 26 of the water vapor supply pipe 4 and adjusts the temperature reducer 23 so that the water vapor reaches the target temperature set based on the temperature of the low calorie gas. The degree of opening of the flow control valve 25 of the pure water supply pipe 24 connected to is controlled.

  Next, a description will be given of a configuration in which water vapor can be discharged to the atmosphere through the water vapor discharge pipe 31. The amount of water vapor is controlled by the flow control valve 29. However, when the detected value of the calorimeter 11 of the low calorie gas supply pipe 3 is rapidly reduced, the control by the flow control valve 29 may cause a problem in response. is there. In such a case, a part of the water vapor is diffused to the atmosphere by the flow control valve 32 of the water vapor discharge pipe 31, so that the supply amount of the water vapor is rapidly reduced to cope with the sudden decrease in the calorie value.

Next, the function and effect of the buffer tank 10 in FIG. 1 will be described. As shown in the figure, the buffer tank 10 is formed with an inlet 10a to which the upstream low calorie gas supply pipe 3 is connected, and an outlet 10b to which the downstream low calorie gas supply pipe 3 is connected is formed separately from the inlet 10a. Is formed. Therefore, all of the low caloric gas that has been sent flows into the buffer tank 10. The buffer tank has a large volume. For example, a low-calorie gas supply pipe 3 having a diameter of about 2 to 3 m is generally installed with a volume of about 20000 to 200000 m ³ . Therefore, the low calorie gas sent while the calorie fluctuates every moment is mixed in the buffer tank. As a result, the fluctuation range of the calorie of the low calorific gas exiting from the outlet 10b of the buffer tank 10 is reduced at a stroke, and the fluctuation speed is reduced at a stroke. That is, calorie fluctuation is greatly relaxed (blunted). Thus, when the calorie fluctuation is alleviated in advance, it becomes very easy to control the increase in calorie by dilution of water vapor downstream. The above phenomenon will be described with reference to FIGS.

FIG. 4 shows a simulation result of a calorie fluctuation mitigation (suppression) state when a low calorie gas that fluctuates in calorie is supplied at a flow rate of 500,000 Nm ³ / hr when the volume of the buffer tank 10 in FIG. 1 is 200000 m ^3. It is a graph to show. The horizontal axis represents time (minutes), and the vertical axis represents the gas calorie value (kcal / Nm ³ ), which is the calorific value of low calorie gas. Moreover, the curve shown with a broken line in the figure has shown the calorie fluctuation | variation (original fluctuation | variation) of the low calorie gas sent to the buffer tank 10. FIG. This is an actually measured sample. A curve represented by a solid line indicates a calorie fluctuation (a fluctuation after suppression) of the low calorie gas exiting from the buffer tank 10. As shown, the calorie of the low caloric gas before entering the buffer tank 10 varies from about 1530 kcal / Nm ³ to about 2360 kcal / Nm ³ . That is, it has a fluctuation range of about ± 21% of the average value (1945 kcal / Nm ³ ). However, according to the result of theoretical calculation of the calorie fluctuation of the low calorie gas exiting from the buffer tank 10 using a simulation model, it is 1780 kcal / Nm ³ to 1960 kcal / Nm ³ , and the fluctuation range is an average value (1870 kcal / Nm). ³ ) is suppressed to about ± 5%. As shown in the figure, the fluctuation period is also greatly relaxed (lengthened). This effect becomes more prominent as the volume of the buffer tank is increased with respect to the supply flow rate of the low calorie gas. In addition, when the original fluctuation cycle and fluctuation width are small, the calorie fluctuation can be suppressed even if the buffer tank volume is reduced from the economical point of view.

5 shows, the low-calorie gas flow rate remains was 500,000 nm ³ / hr, the attenuation state of the calorie variance is shown when the volume of the buffer tank 10 was set to 100000 ³ half of the above. Calorie variance in this case also is suppressed in a range from 1700kcal / Nm ³ to 2040kcal / Nm ³ by the buffer tank 10, the variation width of about ± 9% of the average value (1970kcal / Nm ^3).

6, when the low calorie is a 50000 m ³ volume of the buffer tank 10 in the equipment to be supplied at a flow rate 200000Nm ³ / hr, are shown attenuation state of calorie variance. Calorie variance in this case also is suppressed in a range from 1740kcal / Nm ³ to 2010kcal / Nm ³ by the buffer tank 10, the variation width of about ± 7.2% of the average value (1875kcal / Nm ^3).

Although not shown, when the volume of the buffer tank 10 is set to 25000 m ³ which is half of the above in a facility in which low calorie gas is supplied at a flow rate of 200000 Nm ³ / hr as described above, the fluctuation range is an average value (1875 kcal / Nm ³ ) Of about ± 12%.

Therefore, as shown in FIG. 7, in a facility where low calorie gas is supplied at a flow rate of 200000 Nm ³ / hr, two buffer tanks 10 having a volume of 25000 m ³ are installed in parallel, and both are used during normal operation. Also, it is possible to use only one tank only for unsteady situations such as periodic inspections and malfunctions.

  As described above, the calorie fluctuation of the low calorie gas is greatly suppressed without providing control for positively adding the heat reducing gas and the heat increasing gas only by providing the buffer tank. As a result, the control of mixing the water vapor downstream is very easy. For example, if the calorie fluctuation range of the fuel gas of the gas turbine 2 is set to be ± 10% of the reference calorie value (average value), a buffer tank having a volume that can meet the specifications is provided. In order to make the average value of the calories that fluctuate downstream coincide with the reference calorie value set in the gas turbine 2, it is only necessary to supply a certain amount of water vapor downstream. With regard to the operation of supplying water vapor, it is not necessary to consider the cycle and amplitude of the calorie fluctuation of the low calorie gas.

  In an extreme case, if the average value of the fluctuating calories of the low calorie gas after passing through the buffer tank 10 substantially matches the reference calorie value set in the gas turbine 2, the steam supply equipment is not necessary. Even when both the buffer tank 10 and the steam supply facility are provided, the facility may be operated with the flow control valve 29 of the steam supply pipe 8 of FIG. 1 closed. Of course, if the calorie fluctuation of the generated low calorie gas is not large from the beginning, it is not necessary to install a buffer tank, and it can be adequately handled only by the steam supply equipment.

  FIG. 8 shows another buffer tank 42. This buffer tank 42 may be used in conventional gas turbine equipment, and is included in the device 40 for monitoring the gas amount balance. That is, the gas amount balance monitoring device 40 is for balancing the amount of low calorie gas sent from the upstream side with the amount of gas consumed required by the gas turbine. When there are fluctuations in the supply gas amount and load changes in the gas turbine, it is necessary to balance the supply amount and the consumption amount. When the supply amount becomes unexpectedly excessive, it is diffused into the atmosphere, and when the supply amount becomes insufficient, the load of the gas turbine is reduced or a part of the operation is stopped.

  This gas amount balance monitoring device 40 includes a tank 42 connected to the low calorie gas supply pipe 3 by a communication pipe 41, and a lid member that is airtightly closed at the upper end opening of the tank 42 and is movable up and down in the tank. 43 and an adjustment weight 44 installed on the lid member 43, for example. The lid member 43 moves up and down in the tank by a balance of the total of its own weight, the weight of the weight 44 and the push-down force due to the atmospheric pressure, and the push-up force caused by the internal pressure of the tank 42. Therefore, the lid member 43 moves up and down according to a change in the balance between the supply amount and consumption amount of the low calorie gas. While monitoring the vertical movement of the lid member 43, measures such as atmospheric emission of fuel gas and reduction in turbine load are taken.

  This gas amount balance monitoring device 40 is used for suppressing calorie fluctuation. In addition to the communication pipe 41, the tank 42 is connected to an inlet pipe 45 that communicates with the low calorie gas supply pipe 3 anew. The inlet pipe 45 is provided with a fan 39 for sending low calorie gas to the tank 42. Accordingly, a part of the low calorie gas supplied flows into the tank 42 through the inlet pipe 45 and mixes in the tank 42, and the same amount of gas passes from the tank 42 through the communication pipe 41 to the low calorie gas supply pipe 3. Return to. Therefore, in this case, the communication pipe 41 can also be called an outlet pipe.

  FIG. 9 shows another gas amount balance monitoring device 46 that can be used as calorie fluctuation suppressing means. The gas amount balance monitoring device 46 has a more economical configuration, and has an airtight tank 46 a communicated with the low calorie gas supply pipe 3 by a communication pipe 41. A pressure detection device 47 is installed in the tank 46a, and the internal pressure of the tank 46a is constantly monitored. When the detected pressure reaches the upper limit range, the control device 100 issues a command to increase the gas consumption in the facility, and balances the gas supply and demand. The other structure is the same as that of the above-described apparatus 40 (FIG. 8), and can be sufficiently used as calorie fluctuation suppressing means.

10, in a facility where the low calorie gas varying calorific is supplied at a flow rate 500,000 nm ³ / hr, the volume of the tank 42 (46a) in FIG. 8 or 9 and 200000M ^3, by the fan 39 of 500,000 nm ³ / hr It is a graph which shows the relaxation state of the calorie fluctuation | variation at the time of sending in gas of 200000Nm < ³ > / hr to the tank 42 (46a). The curve shown with a broken line in the figure shows the calorie fluctuation (original fluctuation) of the low calorie gas sent directly from the reduced iron facility S. This is the actual measurement sample described above. A curve represented by a two-dot chain line indicates a simulation result of calorie fluctuation (transient fluctuation) of the low caloric gas that leaves the tank 42 and passes through the communication pipe 41. The curve indicated by the solid line indicates the calorie fluctuation (after-suppression fluctuation) of the gas that reaches the mixer 6 through the low calorie gas supply pipe 3 portion downstream from the communication pipe 41. As before, the calorie of the low calorie gas before entering the tank 42 (46a) has a fluctuation range of about ± 21% of the average value (1945 kcal / Nm ³ ). However, the calorie fluctuation of the gas after joining from the tank 42 (46a) through the communication pipe 41 to the low calorie gas supply pipe 3 is from 1690 kcal / Nm ³ to 2100 kcal / Nm ³ , and the fluctuation range is an average value (1895 kcal). / Nm ³ ) of about ± 11%. This number is an example.

  In this way, it is possible to suppress fluctuations in gas calorie using the existing equipment having the tank 42 (46a). In addition, the low calorific gas can be diluted more effectively with water vapor downstream. 8 and 9, the inlet pipe 45 for feeding the low calorie gas into the tank 42 (46 a) is connected to the upstream side of the outlet pipe 41 in the low calorie gas supply pipe 3, but is not particularly limited to this configuration. Alternatively, the outlet pipe 41 may be connected downstream. A plurality of both the tubes 41 and 45 may be provided.

  FIG. 11 shows another calorie fluctuation suppressing means. This means is a return pipe 48 disposed in the low calorie gas supply pipe 3 for returning a part of the low calorie gas to the upstream side of the low calorie gas supply pipe 3. The return pipe 48 is provided with a fan 49 for pumping low calorie gas upstream. The illustrated return pipe 48 is configured to return to the original low calorie gas supply pipe 3 even if branched from a single suction section into a plurality of branch pipes 48a, but may also be configured from a single return pipe. Alternatively, a single return pipe may be provided in each of a plurality of different parts of the low calorie gas supply pipe 3. Also by such means, the low calorie gas is mixed with the new low calorie gas when returned to the upstream side of the low calorie gas supply pipe 3, and the calorie fluctuation is alleviated. In order to increase this effect, it is only necessary to lengthen the return pipe 48 and increase the volume ratio of the return gas amount to the supply gas amount.

  In the embodiment described above, the mixer 6 for mixing the water vapor with the fuel gas is installed on the outlet side of the low-pressure compressor 16, but it is not limited to this configuration. The installation position of the mixer 6 may be the inlet side of the low-pressure compressor 16, the inlet side of the high-pressure compressor 17, or the outlet side of the high-pressure compressor 17.

  In the embodiment described above, the by-product gas generated by the direct reduction iron manufacturing method is exemplified as the low calorie gas to be used. However, the present invention is not limited to this. Low calorie gas includes blast furnace gas (BFG), coke oven gas (COG), converter gas (LDG), coal bed gas (Coal mine gas, represented as CMG), smelting reduction iron making method By-product gas generated, tail gas generated in GTL (Gas-to-Liquid) process, by-product gas generated during oil refining process from oil sand, gas generated by dust incineration using plasma, Low-calorie gas such as by-product gas generated by chemical reaction of methane gas (Landfill gas) generated in the process of fermentation and decomposition of general waste including raw garbage in the landfill Is included. Needless to say, the present invention can be applied even when two or more kinds of gases are appropriately mixed and used as a mixed gas of BFG and COG.

  According to the present invention, low-calorie gas whose calorie changes from time to time is easy to introduce in large quantities and is diluted with water vapor that does not contain flammable components or oxygen gas. Stable combustion can be continued while suppressing the rise. That is, the above-described effect can be obtained by low equipment cost and operation cost.

It is a piping diagram showing one embodiment of the gas turbine power generation equipment including the low calorie gas supply equipment of the present invention. FIG. 2A is a graph showing an example of the relationship between the calorie fluctuation of the fuel gas (low calorie gas) and the allowable calorie range of the gas turbine, and FIG. 2B shows the change in the flow rate of water vapor supplied to the fuel gas. It is a graph to show. FIG. 3A is a graph showing another example of the relationship between the calorie fluctuation of the fuel gas (low calorie gas) and the allowable calorie range of the gas turbine, and FIG. 3B is a graph showing the flow rate of water vapor supplied to the fuel gas. It is a graph which shows a change. It is the graph which showed an example of the state by which the calorie fluctuation | variation of low calorie gas is eased by passing the buffer tank in FIG. It is the graph which showed the other example of the state by which the calorie fluctuation | variation of low calorie gas is eased by passing through a buffer tank. It is the graph which showed the further another example of the state by which the calorie fluctuation | variation of a low calorie gas is eased by passing through a buffer tank. It is a piping diagram which shows the other example of the buffer tank which can be installed in the gas turbine power generation equipment of FIG. FIG. 6 is a piping diagram showing still another example of a buffer tank that can be installed in the gas turbine power generation facility of FIG. 1. FIG. 6 is a piping diagram showing still another example of a buffer tank that can be installed in the gas turbine power generation facility of FIG. 1. FIG. 10 is a graph showing an example of a state where the calorie fluctuation of low caloric gas is alleviated by passing through the buffer tank of FIG. 8 or FIG. 9. It is a piping diagram which shows the other example of the calorie fluctuation | variation suppression means which can be installed in the gas turbine power generation equipment of FIG.

Explanation of symbols

1 .... Low calorie gas supply equipment
2 ... Gas turbine
3. Low-calorie gas supply piping
4 .... Steam supply piping
6. Mixer
9 ... Dust collector
10 ... Buffer tank
11 .... calorimeter
12 .... Flow meter
13. Mixed gas supply piping
14. Calorimeter
15 .... Motor
16 .... Low pressure compressor
17 ... High pressure compressor
18 .... Cooler
19 .. Combustor
20 ... Flow control valve
21... Filter
22 .... Generator
23 .... Temperature reducer
24 ... Pure water supply piping
25 ... Flow control valve
26 ... Thermometer
27 ... Stop valve
28 ... Flow meter
29 ... Flow control valve
30 ... Check valve
31 ... Water vapor discharge pipe
32 ... Flow control valve
39 ... Fan
40 .... Gas amount balance monitoring device
41 .... Communication pipe
42 ... Tank
43 .. Lid member
44 ... Adjusting weight
45 ... Inlet piping
46 ... Gas amount balance monitoring device
46a ... tank
··· Pressure detector
48 ... Return piping
49 ... Fan
51 .... Waste heat recovery boiler
52 ... Chimney
53... Steam introduction pipe
54 .... Generator
55. Other facilities
56 ... Flow control valve
100 ... Control device
S ... Direct reduction iron equipment

Claims (12)

A low caloric gas supply passage for supplying low caloric gas as fuel gas to the gas turbine;
A water vapor supply passage connected to the low calorie gas supply passage for supplying the water vapor for dilution to the low calorie gas supply passage;
A calorific value detection device for detecting a calorific value in the gas disposed in the low calorie gas supply passage;
A low calorie gas supply facility comprising a control device capable of controlling a water vapor supply operation by a water vapor supply passage based on a detection result of the calorific value detection device.   The control device sets the maximum allowable calorie value of the fuel gas of the gas turbine, and supplies steam from the steam supply passage so that the calorie value of the low calorie gas is maintained below the maximum allowable calorie set value. The low calorie gas supply facility according to claim 1, which is configured. A fuel compressor and a cooler are installed up to the combustor of the gas turbine in the low calorie gas supply passage,
2. A low calorie gas supply facility according to claim 1, wherein a mixer for mixing low caloric gas and water vapor is installed between the fuel compressor and the cooler, and a water vapor supply pipe is connected to the mixer. . A first tank for temporarily storing low calorie gas is disposed in the low calorie gas supply passage,
2. The low tank according to claim 1, wherein the first tank has an inlet and an outlet, the upstream side of the low calorie gas supply passage is connected to the inlet, and the downstream side of the low calorie gas supply passage is connected to the outlet. Calorie gas supply equipment. A second tank for temporarily storing low calorie gas is disposed in the low calorie gas supply passage,
Between the low calorie gas supply passage and the second tank, a gas inlet passage for sending low calorie gas from the low calorie gas supply passage to the second tank and an outlet passage for returning the low calorie gas from the second tank to the low calorie gas supply passage are arranged. Has been established,
The low-calorie gas supply equipment according to claim 1, wherein a first gas pumping device for pumping low-calorie gas toward the second tank is disposed in the inlet passage.   A return passage for returning a part of the low calorie gas to be supplied to the upstream side of the low calorie gas supply passage is disposed in the low calorie gas supply passage, and the low calorie gas is provided upstream of the low calorie gas supply passage in the return passage. The low-calorie gas supply facility according to claim 1, wherein a second gas pumping device that pumps the gas toward the bottom is disposed.   2. The low calorie gas according to claim 1, further comprising a water vapor blocking device disposed in the water vapor supply channel and capable of blocking and opening the channel, and a water vapor releasing device disposed upstream of the water vapor blocking device. Supply equipment.   The low-calorie gas supply facility according to claim 1, wherein the steam is steam generated by a boiler that uses exhaust heat from the turbine. A gas turbine,
A low-calorie gas supply facility for supplying low-calorie gas as fuel gas to the gas turbine;
A gas turbine facility, wherein the low calorie gas supply facility is the low calorie gas supply facility according to any one of claims 1 to 7. A plurality of gas turbines are installed, and each gas turbine is provided with the low-calorie gas supply equipment and the exhaust heat recovery boiler.
The gas turbine equipment according to claim 9, wherein the steam introduced into the steam supply passage of the low calorie gas supply equipment is steam generated by an exhaust heat recovery boiler installed in a gas turbine other than the corresponding gas turbine. A plurality of gas turbines are installed, and each gas turbine is provided with the above low calorie gas supply equipment and an auxiliary boiler,
The gas turbine equipment according to claim 9, wherein the steam introduced into the steam supply passage of the low calorie gas supply equipment is steam generated by an exhaust heat recovery boiler installed in a gas turbine other than the corresponding gas turbine. A calorie measuring step for measuring the calorific value of the low calorie gas supplied to the gas turbine as fuel gas;
A method for suppressing an increase in calorie of low-calorie gas for a gas turbine fuel, comprising a step of mixing a water vapor for dilution into the low-calorie gas so that the measurement result does not exceed a set allowable caloric value.

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