KR100906267B1 - Gas turbine apparatus, apparatus for supplying fuel gas and method for suppressing calorie elevation of fuel gas - Google Patents

Abstract

Provided is a low calorie gas supply facility capable of supplying fuel gas as a stable gas turbine fuel by pressing a spike in its calories. The low-calorie gas supply facility 1 is connected to a low-calorie gas supply pipe 3 for supplying gas to the gas turbine 2 as a fuel, and a fuel gas supply pipe 3, in an acid production plant and a nitrogen production plant. Calories installed in the waste nitrogen supply pipe 4 and the low calorie gas supply pipe 3 for supplying the waste nitrogen generated in at least one place 20 to the low calorie gas supply pipe 3, and for detecting the calorific value of the gas. The meter 11 and the control apparatus 100 are provided, and when the control apparatus 100 detects the calorimeter 11 exceeding the reference value, the waste nitrogen is discharged from the waste nitrogen supply pipe 4. To control it.

Gas, turbine, fuel, gas, calories, rise, suppression

Description

GAS TURBINE APPARATUS, APPARATUS FOR SUPPLYING FUEL GAS AND METHOD FOR SUPPRESSING CALORIE ELEVATION OF FUEL GAS}

The present invention relates to a gas turbine installation, a fuel gas supply facility and a method for suppressing calorie rise of fuel gas. More specifically, a fuel gas supply facility for supplying a gas whose heating value (also called a "calorie") fluctuates, such as a low-calorie gas, as a fuel of a gas turbine, a gas turbine facility equipped with this fuel gas supply facility, and the said gas A method of suppressing an increase in the calorific value of a gas for turbine fuel.

In the steelmaking field, for example, when pig iron is produced by a blast furnace method, a furnace gas (Blast Furnace Gas, hereinafter referred to as 'BFG') is generated as a by-product gas in a blast furnace. Since the total calorific value of BFG reaches up to about half of the calorific value of the coke used, BFG has been used in various ways in steel mills in order to reduce steelmaking costs. BFG generates about 3,000Nm3 per ton of coke, and its composition is 10 to 18% by volume of carbon dioxide (CO ₂ ) (hereinafter referred to as '%'), 22 to 30% of carbon monoxide (CO), nitrogen (N ₂ ) is 52 to 60%, hydrogen (H ₂ ) is 0.5 to 4%, and methane (CH ₄ ) is about 0.5 to 3%.

Since BFG contains 2 to 10 g / Nm3 of fume dust in addition to these, after removing it to about 0.01g / Nm3 from a vibration damper, it is a fuel gas having a calorific value of 800 kcal / Nm3. It is used for a coke oven, a heating furnace, a boiler, etc. In recent years, even in gas turbines, combustion of low-calorie gas is enabled by the improvement of the technology, and there are increasing cases of generating electricity by using BFG as a gas turbine fuel. The low calorie gas here is defined as a gas whose calorific value is about 12 MJ / Nm 3 or less. As the low-calorie gas, as described later, not only the furnace gas (BFG) but also various other kinds of gases such as converter gas (LDG) and mixed gas thereof are included.

On the other hand, in recent years, new steelmaking processes other than the blast furnace method (for example, direct reduction ironmaking methods such as FINEX and COREX) have been developed, and a combustion method that can also be applied to the effective use of by-product gas generated from these new processes. Development is expected. In any steelmaking process, the by-product gases generated (gas composition or calories) will vary depending on the plant or operation. Even in the same facility, it varies depending on the characteristics of each raw material and the degree of reaction.

Looking at the calorie, the most important characteristic of using by-product gas as the fuel of a gas turbine, if the gas turbine exceeds the upper limit of the permissible fluctuation of calories (for example, about + 10% of the average calorie value) In other words, when the calories are rapidly increased, the combustion temperature in the combustor of the gas turbine is abruptly abnormal high temperature. Due to this, there is a possibility that the burner part, the vane and the rotor blade of the turbine may be damaged, and the damage that may shorten the life may occur. In this case, economical continuous operation of the gas turbine installation becomes difficult.

Techniques for diluting with so-called pure nitrogen gas (N ₂ ) in order to suppress fluctuating calories of by-product gas are known (see Patent Document 1 and Patent Document 2, for example). However, with an inert gas such as a N ₂ it was purified by high purity if the dilution of the by-product gas, according to the variation value of the calorie is N ₂ Expensive inert gases such as these must be used in large quantities. In addition, it is very difficult to continuously secure a large amount of inert gas except in a special industrial field. In addition, it is necessary to provide a large amount of inert gas storage facilities and various equipment facilities for supplying gas including piping. For this reason, purchasing and using pure inert gas lowers the economics of gas turbine power generation and impedes the technical superiority of the gas turbine which exhibits high efficiency.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-155762

Patent Document 2: Japanese Patent Application Laid-Open No. 9-317499

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has a fuel gas supply facility capable of alleviating calorie fluctuations of fuel gas for a gas turbine, which is low in equipment cost and operating cost, and a gas turbine facility having the fuel gas supply facility; It is an object of the present invention to provide a method of suppressing an increase in the calorific value of a gas for a gas turbine fuel.

Fuel gas supply facilities of the present invention for the above purpose,

A fuel gas supply passage for supplying gas to the gas turbine as fuel;

A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage;

It is provided in the said fuel gas supply passage, and is provided with the calorific value detection apparatus for detecting the calorific value in gas.

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According to the present invention, waste nitrogen generated as a by-product to be discarded in an oxygen production plant and waste nitrogen produced in a nitrogen production plant but contained in a small amount of oxygen can be recovered and used as a dilution gas of fuel gas. By containing a large amount of nitrogen, which is a non-combustible gas, and extremely easy procurement, by mixing inexpensive waste nitrogen and diluting the fuel gas, it is possible to suppress a calorie increase of the fuel gas. Here, the calorific value detecting device includes not only an apparatus for directly measuring the calorific value of the gas (eg, a so-called 'calorimeter') but also an apparatus for measuring the content rate of the combustible component in the gas.

A control device capable of controlling the waste nitrogen supply operation by the waste nitrogen supply passage may be further provided based on the detection result of the calorific value detection device.

The control device is configured to supply waste nitrogen from the waste nitrogen supply passage when the maximum allowable caloric value of the gas supplied as fuel to the gas turbine is set and the caloric value of the fuel gas exceeds the maximum allowable calorie set value. can do.

An inert gas supply passage for supplying an inert gas to the fuel gas supply passage is connected, and the calorific value detecting device is provided with the waste nitrogen supplied to the fuel gas supply passage by the waste nitrogen supply passage. A fuel gas supply facility configured to control the inert gas supply operation by the inert gas supply passage on the basis of the detection result of is preferable. This is because if the supply of the waste nitrogen is stopped or reduced, the dilution of the fuel gas can be compensated for by the high purity inert gas when the suppression of calorie increase of the fuel gas is insufficient.

In the waste nitrogen supply passage, a storage tank for temporarily storing waste nitrogen supplied from at least one of an oxygen production plant and a nitrogen production plant may be installed. This is to maintain a stable supply of waste nitrogen.

In the waste nitrogen supply passage, an oxygen concentration fluctuation suppression tank for temporarily storing waste nitrogen supplied from at least one of an oxygen production plant and a nitrogen production plant is provided, and a gas inlet and a gas outlet are provided in the oxygen concentration fluctuation suppression tank. It is preferable to form a, to connect the upstream side of the waste nitrogen supply passage to the gas inlet, and connect the downstream side of the waste nitrogen supply passage to the gas outlet. The waste nitrogen supplied while the oxygen concentration is mixed is mixed in the oxygen concentration fluctuation suppression tank, whereby the concentration fluctuation of the trace amount of oxygen which is a by-product component contained in the waste nitrogen is made uniform, and the safety as the dilution gas of the waste nitrogen is stabilized. Because it becomes.

In each of the above facilities, a tank for temporarily storing fuel gas is provided in the fuel gas supply passage, and the tank has a gas inlet and a gas outlet, and the gas inlet has an upstream side of the fuel gas supply passage. It is preferable that the downstream side of the fuel gas supply passage is connected to the gas outlet. The waste gas in the downstream part of the tank is reduced because the fuel gas supplied through the fuel gas supply passage is temporarily stored in the tank and mixed therein, thereby decreasing the calorie fluctuation rate and the calorie fluctuation rate is alleviated. This is because it is easier to control calorie equalization by dilution using. The calorific value detecting device described above is provided in the fuel gas supply passage, but in a facility in which a tank is provided in the fuel gas supply passage, such a tank also constitutes a fuel gas supply passage, so that the calorific value detecting device is provided in the fuel gas supply passage. The thing includes installing in the said tank.

Two types of gas inlets are formed in the tank, one of the gas inlets is connected to the upstream side of the fuel gas supply passage, and the other gas inlet is connected to the return passage connected to the downstream side of the fuel gas supply passage. In the return passage, a gas feeding device for feeding fuel gas toward the tank can be provided.

A gas return path is connected between the fuel gas supply passage upstream from the tank and the fuel gas supply passage downstream from the tank, and the gas for pumping fuel gas toward the fuel gas supply passage upstream from the tank is connected to the return passage. A pressure feeding device can be installed.

A tank for temporarily storing fuel gas is provided in the fuel gas supply passage, an outlet passage for returning fuel gas from the tank to the fuel gas supply passage between the fuel gas supply passage and the tank, and a fuel gas supply passage. It is preferable that the fuel gas supply facility is provided with an upstream side inlet passage through which the fuel gas is sent from the upstream side to the tank from the connection point with the outlet passage in the shunt. This is because the fuel gas is mixed therein by the tank as well, so that the width of the calorie fluctuation is reduced while the rate of calorie fluctuation is moderated.

In addition, the tank mentioned above may be a fixed type tank which does not change internal volume at least, or may be a tank of the internal volume variation type used as a gas holder which monitors the supply-demand balance of gas in a conventional gas turbine installation etc. good. A tank having an internal volume variation type is a tank having a lid member that is hermetically mounted so as to move up and down in response to a tank internal pressure, and is balanced by actively moving the lid member up and down by a driving device. It is a tank which can select a tank volume to maximize the effect.

Further, the fuel gas supply facility has a downstream in which fuel gas is sent to the tank from the downstream side instead of the connection point with the outlet passage in the fuel gas supply passage in place of or along with the upstream side inlet passage. A side inlet passage may be provided, and a gas pressure feeding device for feeding fuel gas toward the tank may be provided in the downstream side inlet passage.

In the fuel gas supply facility having the tank, a return passage is connected between the downstream side of the connection point to the outlet passage in the fuel gas supply passage and the upstream side of the connection point to the inlet passage in the fuel gas supply passage. In the return passage, a gas feeding device for feeding fuel gas toward the upstream fuel gas supply passage can be provided.

It is preferable to provide a stirring device for stirring the gas inside the tank described above.

And a return passage connected between an upstream portion and a downstream portion in the fuel gas supply passage, wherein a portion of the fuel gas flowing through the fuel gas supply passage is transferred upstream from the downstream portion of the fuel gas supply passage. It is preferable that a gas pumping device that is pumped toward the front is provided. This is because the same operation as that by the tank is achieved.

Gas turbine equipment of the present invention,

A gas turbine and a fuel gas supply facility for supplying gas as fuel to the gas turbine are provided, and the fuel gas supply facility is any of the fuel gas supply facilities described above.

The method of suppressing the calorie increase of the fuel gas for the gas turbine fuel of the present invention,

A calorie measurement step of measuring the calorific value of the gas supplied as fuel to the gas turbine,

And a waste nitrogen incorporating step of incorporating waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant into the fuel gas when the measurement result exceeds a set allowable calorie value.

Also, when it is determined that the calorific value measurement result does not fall below the set allowable calorie value even by the waste nitrogen supply, a calorie increase suppressing method further comprising the step of incorporating an inert gas into the fuel gas.

According to the present invention, a facility for supplying a gas turbine with a fuel gas that can vary in calories, such as a process byproduct gas, is realized by a low installation cost and an operating cost. For example, when supplying a fluctuating gas such as a low calorie gas as fuel, in order to suppress calorie increase of the gas, a large amount of waste nitrogen easily occupied by a nonflammable gas called N ₂ is obtained in large quantities. Because you can.

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

2 is a piping diagram schematically showing a gas turbine power generation facility including a low calorie gas supply facility according to another embodiment of the present invention.

3 is a graph showing an example of the relationship between the mixing ratio of low calorie gas and air and the flammability limit of the mixer, taking the volume ratio of low calorie gas on the horizontal axis, and taking the temperature on the vertical axis.

4 is a graph showing an example of a state in which calorie fluctuation of low-calorie gas is relaxed as it passes through the buffer tank of FIG. 1 or 2.

5 is a graph showing another example of a state in which calorie fluctuation of low-calorie gas is relaxed as it passes through a buffer tank.

6 is a graph showing another example of a state in which calorie fluctuation of low calorie gas is relaxed as it passes through a buffer tank.

7 is a piping diagram illustrating another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

8 is a piping diagram illustrating another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

FIG. 9 is a piping diagram illustrating still another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

FIG. 10 is a graph illustrating an example of a state in which calorie fluctuation of low calorie gas is relaxed as it passes through the buffer tank of FIG. 8 or FIG. 9.

FIG. 11 is a piping diagram illustrating still another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

12 is a piping diagram showing another example of calorie fluctuation suppressing means that can be installed in the gas turbine power generation facility of FIG. 1 or FIG. 2.

FIG. 13 is a piping diagram illustrating still another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

14 is a piping diagram illustrating still another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

FIG. 15 is a piping diagram illustrating still another example of a buffer tank that may be installed in the gas turbine power generation facility of FIG. 1 or 2.

<Explanation of symbols for the main parts of the drawings>

1: low calorie gas supply equipment 2: gas turbine

3: low calorie gas supply line 4: waste nitrogen supply line

5: Mixer 6: Dust Collector

7: Calorific value detector (calorimeter) 8: Flow meter

9: mixed gas supply piping 10: buffer tank

11: calorimeter 12: oximeter

13: low pressure compressor 14: high pressure compressor

15: cooler 16: combustor

17: flow control valve 18: filter

19: generator 20: source (of waste nitrogen)

21: nitrogen storage tank

22: oxygen concentration fluctuation suppression tank (of waste nitrogen)

23: oximeter 24: fan

25: non-return valve 26: stop valve

27: flow meter 28: flow control valve

29: stop valve 30: non-return valve

31: waste nitrogen discharge pipe 32: flow control valve

33: low calorie gas supply facility 34: inert gas supply piping

35: stop valve 36: flow meter

37: flow control valve 38: common piping

39: fan 40: gas amount balance monitoring device

41: communication pipe 42: tank

43: lid member 44: adjustment weight

45: upstream side inlet piping 46: gas amount balance monitoring device

47: tank 48: pressure detection device

49: return piping 50: downstream side inlet piping

51: stirring device 52: return piping

100: control device S: direct reduction steelworks

EMBODIMENT OF THE INVENTION The embodiment of the fuel gas supply facility of this invention, the gas turbine facility provided with the same, and the method of suppressing the heat generation increase of fuel gas are described, referring an accompanying drawing.

1 is a piping diagram showing an outline of a gas turbine facility including a low calorie gas supply facility 1 which is an embodiment of a fuel gas supply facility of the present invention. As a gas turbine installation, the gas turbine power generation facility is illustrated. As described above, the low calorie gas is defined as a gas whose calorific value is about 12 MJ / Nm 3 or less. Low-calorie gas often fluctuates characteristics such as calories.

The low calorie gas supply facility 1 is a low calorie gas supply pipe 3 for supplying the gas turbine 2 as a fuel by-product gas (hereinafter referred to as 'low calorie gas') generated in the direct reduction steel making facility S. And control the operation of the waste nitrogen supply pipe 4 for supplying waste nitrogen as the diluent gas to the low calorie gas supply pipe 3 in order to suppress the calorie increase of the low calorie gas, and the operation of the low calorie gas supply facility 1. The control apparatus 100 for doing so is provided.

The reason why the waste nitrogen is mixed in order to dilute the low calorie gas and suppress its calorie rise is because the waste nitrogen contains a large amount of N ₂ , but does not contain a flammable gas. The waste nitrogen contains a small amount of nitrogen released from the oxygen production plant used in the furnace method and the direct reduction iron production method such as the FINEX method or the COREX method, and the nitrogen discharged from the nitrogen production plant added to the oxygen production plant. Nitrogen. In the case of direct reduction iron production methods such as the FINEX method and the COREX method, since oxygen is used, it is essential to install an oxygen production plant that produces a large amount of oxygen. Oxygen is also used in the furnace process, so oxygen production plants are used, even if there are differences in scale. The oxygen production plant produces nitrogen by separating nitrogen from air, but nitrogen after separating oxygen is usually discharged to the atmosphere as waste nitrogen. On the other hand, in many cases, a nitrogen production plant is added to an oxygen production plant to produce high purity nitrogen, but even in this case, nitrogen containing a small amount of oxygen is released into the atmosphere as waste nitrogen. Such waste nitrogen has a gas composition of about 95 to 98% by mass of nitrogen gas and about 2 to 5% of oxygen, and is an extremely safe dilution gas in view of the flammability limit of low calorie gas. Recovering and using such a large amount of nitrogen which is disposed of in large quantities makes operation costs particularly low.

In the upstream portion of the mixer 5 of the low-calorie gas supply pipe 3, a dust collector 6 for dust-reducing the low-calorie gas sent from the direct reduction iron making facility S, and a buffer for storing the low-calorie gas as a primary. The tank 10 is provided. The buffer tank 10 is provided 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. In the buffer tank 10 of FIG. 1, its inlet 10a and outlet 10b are formed near the lower end of the tank circumferential wall, but are not particularly limited to this formation position. For example, you may form in the center part of a tank circumference wall, an upper part, a bottom part of a tank, etc.

The buffer tank 10 has a relatively large capacity, and low calorie gas that stays while calorie fluctuates from time to time is mixed inside the buffer tank 10. The effect is mentioned later. On the downstream side of the buffer tank 10, a calorific value detector (calorimeter) 7 for detecting the calorific value of the low calorie gas and a flowmeter 8 for measuring the flow rate are provided. The installation position of this flowmeter 8 is not limited to the upstream side of the mixer 5. The downstream side of the mixer 5 may be sufficient. For example, it may be between the high pressure compressor 14 and the combustor 16 described later.

The installation position of the calorific value detection device 7 is not limited to the downstream side of the buffer tank 10, and may be, for example, an upstream side of the buffer tank 10. By detecting the calorie fluctuation of the gas in advance on the upstream side of the buffer tank 10, it is possible to more reliably control the calorific value using the mixer 5. In addition, in the buffer tank 10, a calorific value detector is provided on the downstream side together with the upstream side of the buffer tank 10 and the gas calorie fluctuation suppressing effect of the buffer tank 10 is monitored by both calorific value detectors. It is possible to grasp the overall performance of the system for suppressing calorie fluctuations in combination with gas mixing. The calorific value detection device can also be mounted directly on the buffer tank 10. In addition to the calorific value detecting device 7 in the low calorie gas supply pipe 3, a separate calorific value detecting device may be attached to the buffer tank 10.

Here, as the calorific value detecting device 7, a so-called 'calorimeter' for directly measuring the calorific value of the gas, an apparatus for measuring the content rate (concentration) of the combustible component, and the like are used. When the detection speed is important, it is preferable to use a flammable gas concentration detector at present. The concentration which detects the concentration of the component corresponding to the kind of the combustible component mainly contained in the low-calorie gas to be applied and the combustible component (for example, CO is a by-product gas in the direct reduction iron production method). You may use a detector. In this specification, the whole calorific value detection apparatus is called "calorimeter".

The lower portion of the lower calorie gas supply pipe 3 than the mixer 5 is routed there to the gas turbine 2 in the state where the low calorie gas is mixed with the waste nitrogen. It is called). The mixed gas supply piping 9 is provided with a calorimeter 11 and an oxygen concentration meter 12 for measuring the oxygen concentration in the mixed gas. On the downstream side of the oxygen concentration meter 12, a low pressure fuel gas compressor (hereinafter referred to as a "low pressure compressor") 13 and a high pressure fuel gas compressor (hereinafter referred to as a "high pressure compressor") 14 of the gas turbine 2 are provided. It is installed in order. Between both compressors 13 and 14, a cooler 15 for cooling a mixed gas as a fuel gas is provided. The fuel pipe 9a connected from the high pressure compressor 14 to the combustor 16 of the gas turbine 2 is provided with a flow regulating valve (hereinafter referred to as a 'flow regulating valve') 17 for regulating the turbine output. It is. Reference numeral '18' denotes a filter installed in a pipe for supplying air to the combustor 6. The generator 19 is connected to the gas turbine 2.

FIG. 1 shows a type of rotationally driven by the turbine 2 together with both compressors 13 and 14, but is not limited thereto, and both compressors 13 and 14 are not coaxially connected to the turbine 2. Instead, it may be configured to be driven by a dedicated motor.

The waste nitrogen supply facility will be described. The waste nitrogen supply pipe 4 extends from the oxygen production plant (or nitrogen production plant) 20, which is a source of waste nitrogen, to the mixer 5. The waste nitrogen supply pipe 4 is provided with a nitrogen storage tank 21 and an oxygen concentration fluctuation suppressing tank 22. Regarding the mounting positions of these tanks 21 and 22, any may be provided on the upstream side (downstream side).

The nitrogen storage tank 21 temporarily stores waste nitrogen from the supply source 20, so that even if the supply of waste nitrogen from the supply source 20 suddenly stops or significantly decreases, the predetermined time may be reduced. It is installed for the purpose of continuously supplying waste nitrogen. In addition, fluctuations in the internal pressure of the waste nitrogen supply pipe 4 can be alleviated. The nitrogen storage tank 21 may be connected to the waste nitrogen supply pipe 4 with only one line of communication pipe, or may be formed with an inlet and an outlet and connected to each of the upstream and downstream sides of the waste nitrogen supply pipe 4. good.

The oxygen concentration fluctuation suppressing tank 22 is provided for the purpose of suppressing the fluctuation of the oxygen concentration in waste nitrogen. If the fluctuation of the oxygen concentration is negligible, it is not necessary to provide the oxygen concentration fluctuation suppressing tank 22. The oxygen concentration fluctuation suppressing tank 22 is formed with an inlet 22a and an outlet 22b, and 22a and 22b are connected to the waste nitrogen supply pipe 4 by the inlet pipe and the outlet pipe, respectively. With this structure, all of the waste nitrogen supplied by the waste nitrogen supply pipe 4 flows into the oxygen concentration fluctuation suppressing tank 22 and is mixed. As a result, even if there is a fluctuation in oxygen concentration in the supplied waste nitrogen, the fluctuation range of the oxygen concentration of the waste nitrogen exiting from the outlet 22b of the oxygen concentration fluctuation suppressing tank 22 is reduced, and the fluctuation rate is lowered. . That is, the fluctuation of oxygen concentration is greatly alleviated (suppressed). When the oxygen concentration is relaxed in this manner, the safety of the waste nitrogen as a dilution gas is stably exhibited.

The oxygen concentration fluctuation suppressing tank 22 can also be used as the nitrogen storage tank 21. In this case, the nitrogen storage tank 21 in the figure does not need to be installed, and only the oxygen concentration fluctuation suppressing tank 22 needs to be provided.

On the downstream side of the oxygen concentration fluctuation suppression tank 22, the waste nitrogen supply pipe 4 is branched into two lines for convenience during maintenance, and sucks waste nitrogen from the supply source 20 to supply fuel gas supply pipe ( A fan 24 as a pressure feeding device for pumping the waste nitrogen supply pipe 4 toward 3) is provided. The fan 24 is not necessary when the pressure of the waste nitrogen at the time generated from the source 20 is high enough.

On the downstream side of each fan 24, a non-return valve 25 is provided to prevent the reverse flow to the fan 24 side. The waste nitrogen supply pipe 4 is integrated in one line again on the downstream side of the both side check valves 25. A portion of the waste nitrogen supply pipe 4 downstream from the integration point includes a stop valve 26, a flow meter 27, a flow control valve 28, an oximeter 23, a stop valve 29 and a check valve 30. ) Is finally installed, and the waste nitrogen supply pipe 4 is connected to the mixer 5. The installation position of the oxygen concentration meter 23 is not particularly limited to the position shown, and may be provided at any position on the waste nitrogen supply pipe 4. In suppressing calorie fluctuations of low-calorie gas, when the oxygen concentration meter 23 is used, it is not necessary to use the oxygen concentration meter 12 of the mixed gas supply pipe 9 for the control. The non-return valve 30 is for preventing the low calorie gas from flowing back to the waste nitrogen supply pipe 4. The nitrogen storage tank 21 and the oxygen concentration fluctuation suppressing tank 21 mentioned above may be provided between the backflow prevention valve 25 and the stop valve 26, respectively.

A waste nitrogen discharge pipe 31 for releasing waste nitrogen into the atmosphere is provided between the stop valve 26 of the waste nitrogen supply pipe 4 and the flow meter 27. The waste nitrogen discharge pipe 31 is provided with a flow regulating valve 32.

Next, an example of the operation control of the said facility by the control apparatus 100 is demonstrated. First, the low calorie gas is pumped toward the gas turbine 2 while monitoring the calorimeter 7 and the flowmeter 8 of the low calorie gas supply pipe 3. At this time, in the waste nitrogen supply pipe 4, the stop valve 26 is opened, the flow control valve 28 is closed, and the flow control valve 32 of the waste nitrogen discharge pipe 31 is open, and the fan 24 is opened. It's working. That is, waste nitrogen is sucked in and is discharged | emitted from the waste nitrogen discharge piping 31 to air | atmosphere. The other stop valve 29 is open.

In the control apparatus 100, the allowable calorie range on the fuel gas use of each gas turbine 2 is set. That is, the reference calorie value (for example, 1,600 kPa / Nm3) and the fluctuation range (for example, ± 10% of the reference calorie value). And the flow rate control valve 28 of the waste nitrogen supply pipe 4 so that the calorie value of the low calorie gas does not exceed the upper limit calorie value (for example, + 10% and 1,760 kPa / Nm 3) of the allowable variation. It opens and adjusts the flow regulating valve 32 of the waste nitrogen discharge piping 3 to a closing direction. This mixes waste nitrogen with low-calorie gas and controls the calorie value to fall within the acceptable range. When supplying waste nitrogen and supplying N ₂ to be described later, together with monitoring of the calorimeter 7 and the flow meter 8, the calorimeter of the mixed gas supply pipe 9 to determine suitability of the final calorie value. Monitor (11). When supplying the waste nitrogen, the oxygen concentration of the supply waste nitrogen is monitored by the oxygen concentration meter 23 of the waste nitrogen supply pipe 4 or the oxygen concentration meter 12 of the low calorie gas supply pipe 3 as described later. By monitoring the oxygen concentration of the fuel gas after the waste nitrogen is mixed.

Next, a description will be given of the configuration in which the waste nitrogen can be discharged to the atmosphere from the waste nitrogen supply pipe 4 through the waste nitrogen discharge pipe 31. The amount of waste nitrogen supplied is usually controlled by the flow regulating valve 28. When the detection value of the calorimeter 7 of the low-calorie gas supply pipe 3 decreases rapidly (the calorie value of the low-calorie gas drops sharply), the response is problematic for the control by the flow regulating valve 28. There is also a possibility. In such a case, the flow rate regulating valve 32 of the waste nitrogen discharge pipe 31 is opened to dissipate a portion of the waste nitrogen to the atmosphere, thereby rapidly reducing the supply amount of waste nitrogen to cope with a sudden drop in calorie value.

2 shows another form of a low calorie gas supply facility. This low-calorie gas supply facility 33 installs an inert gas supply facility in the low-calorie gas supply facility 1 of FIG. Since other configurations are the same as those of the low calorie gas supply equipment 1 of FIG. 1, the same equipment is given the same reference numerals, and detailed description thereof is omitted. The inert gas supply facility of FIG. 2 is equipped with the inert gas supply piping 34 for supplying the high purity inert gas to the low-calorie gas supply piping 3. This is provided to stably supply the dilution gas when the above-described oxygen production plant (nitrogen production plant) 20, which is a source of waste nitrogen, stops operation for some reason or the generation amount of waste nitrogen is greatly reduced. In this embodiment, since nitrogen gas (N ₂ ) is used as the inert gas, this inert gas supply pipe 34 is referred to as N ₂ supply pipe 34. The inert gas is not limited to N ₂ and may be CO ₂ or helium (He).

In this embodiment N ₂ The supply pipe 34 is connected to the waste nitrogen supply pipe 4, and the common pipe 38 of waste nitrogen and N ₂ is connected to the low calorie gas supply pipe 3. This common pipe 38 is connected to the low calorie gas supply pipe 3 by the mixer 5. When it is considered to mix the inert gas and the waste nitrogen and supply it to the low-calorie gas supply pipe 3, the gas for mixing both gases at the connection portion between the N ₂ supply pipe 34 and the waste nitrogen supply pipe 4. You may install a mixer.

4 and 34 may be directly connected to the mixer 5 without joining the waste nitrogen supply pipe 4 and the N ₂ supply pipe 5, however, as shown in FIG. , 34) is preferably connected in advance. The N ₂ supply pipe 34 is provided with a stop valve 35, a flow meter 36, and a flow control valve 37 in order from the upstream side. The stop pipe 29 and the backflow prevention valve 30 are provided in the said common pipe 38 sequentially from an upstream side similarly to the waste nitrogen supply pipe 4 of the low-calorie gas supply facility 1 of FIG.

When the control apparatus 100 determines from the measurement result of the calorimeter 11 of the mixed gas supply pipe 9 that the calorie value is still not maintained in an allowable range even by waste nitrogen supply, the N ₂ supply pipe 34 While monitoring the flowmeter 36 of the control panel, N ₂ is mixed with the low calorie gas to control the calorie value to fall within the allowable range by adjusting the opening of the flow control valve 37.

Since the waste nitrogen generated in the oxygen production plant or the nitrogen production plant contains 2 to 5% of oxygen, when the waste nitrogen is mixed with the low calorie gas, the oxygen content (oxygen concentration) of the mixed gas is increased to a small degree. If a certain proportion of oxygen is contained in the combustible gas, theoretically the combustible gas falls within the combustible range at a predetermined temperature. In order to examine also the case where waste nitrogen containing about 2 to 5% of oxygen is mixed with a low calorie gas, the allowable maximum mixing ratio of the low calorie gas of air containing a relatively large amount of oxygen may be used.

That is, since air contains oxygen at a constant volume ratio (unchanged at about 21%), the flammability limit of the mixture of air and low calorie gas is determined with respect to the volume ratio of low calorie gas or air, and from this, the maximum allowable mixing ratio of air. It is convenient to set and calculate and set the maximum allowable mixing ratio of the waste nitrogen based on the ratio between the data and the oxygen content ratio. For example, the allowable maximum mixing ratio of air is multiplied by the ratio between the oxygen content of air (21%) and the oxygen mixing rate of waste nitrogen to be employed (about 2 to 5%). It demonstrates below.

In FIG. 3, the flammable range is shown by the relationship of the volume ratio of a low calorie gas and temperature with respect to the mixed gas of low calorie gas and air. In the figure, the curve which follows the round black spot of the left side shows the minimum volume ratio (maximum volume ratio of air) of the low-calorie gas in the combustible range of mixed gas. The curve following the square black spot on the right shows the maximum volume ratio (minimum volume ratio of air) of the low calorie gas in the combustible range of the mixed gas. The range between the two curves is the flammable range. Since the calorie value of low calorie gas fluctuates, both curves also fluctuate. Thus, based on such data, if air is considered as a diluent gas, for example, the maximum allowable mixed volume fraction of air is 20% by volume, taking into account the safety factor (80% by volume of low calorie gas). ) The ratio is smaller (20%) than the minimum volume fraction of air represented by the curve following the square black spot on the right. This figure is an example.

Here, the ratio of the oxygen content rate of air and waste nitrogen is 21/5. The oxygen content of the waste nitrogen is about 2 to 5%, but is set at 5% by taking the direction of safety. Since the maximum allowable volume ratio of air is 20%, the maximum allowable mixed volume ratio of waste nitrogen is 20% x 21/5 kPa 84%. Although the maximum allowable mixing volume fraction of such waste nitrogen is set in the controller 100, these are the maximum allowable mixing volume ratios derived from the flammable limits of the mixed gas. In practice, waste nitrogen is not mixed in low-calorie gas until it reaches 84%.

The above control is performed based on the detection result of the flowmeter 8 of the low-calorie gas supply piping 3 and the flowmeter 27 of the waste nitrogen supply piping 4. In addition, the oxygen concentration of the mixed gas and the oxygen concentration of the waste nitrogen are always monitored together by the oxygen concentration meter 23 (may be '12'). To cope with unexpected fluctuations in oxygen concentration.

Next, the effect of the buffer tank 10 of FIG. 1 or FIG. 2 is demonstrated. As described above, all of the sent low-calorie gas flows into the buffer tank 10. The volume of this buffer tank is large, for example, the thing of 20,000-200,000m <3> in volume is normally provided with respect to the low calorie gas supply piping 3 of diameter 2-3m. Every minute calorie fluctuates, low-calorie gas is mixed in a buffer tank. Gas mixing in the tank referred to in this specification means mixing of time difference, so to speak. That is, the low-calorie gas which flowed in into the buffer tank 10 simultaneously distributes from the part which flows out into the outlet 10b relatively quickly to the part which stays in the buffer tank 10 late. On the other hand, since new gas flows in continuously from the inlet 10a, the gas which flowed in in the past and the gas which flowed in newly are mixed continuously. This is called time difference mixing.

As a result of this time difference mixing, the calorie fluctuation range of the low-calorie gas exiting from the outlet 10b of the buffer tank 10 is reduced, and the fluctuation rate is lowered. That is, the calorie fluctuation is greatly alleviated (suppressed). When the calorie fluctuation is alleviated in advance in this manner, it becomes very easy to control calorie rise suppression by dilution with waste nitrogen or the like downstream. The above phenomenon is demonstrated referring FIGS. 4-9.

4 is a simulation of the relaxation (suppression) of the calorie fluctuation when the calorie fluctuating low-calorie gas is supplied at a flow rate of 500,000 Nm 3 / hr when the volume of the buffer tank 10 of FIG. 1 or FIG. 2 is 200,000 m 3. A graph showing the results. The horizontal axis represents time (minutes), and the vertical axis represents gas calorie value (mm 3 / Nm 3), which is a calorific value of low calorie gas. Moreover, the curve shown by the dotted line in the figure shows the calorie fluctuation (original fluctuation) of the low calorie gas sent to the buffer tank 10. This is one sample actually measured. The curve shown by the solid line shows the calorie fluctuation (change after suppression) of the low calorie gas exiting from the buffer tank 10. As shown, the calorie of the low calorie gas before entering the buffer tank 10 varies from about 1,530 kcal / Nm3 to about 2,360 kcal / Nm3. That is, it has a fluctuation range of about ± 21% of the average value (1945 kV / Nm 3). According to the theoretical calculation of the calorie fluctuation of the low-calorie gas exiting the buffer tank 10, it is from 1,780 mW / Nm3 to 1,960 mW / Nm3, and the variation range is about ± 5% of the average value (1,870 mW / Nm3). It is suppressed until. Also in the fluctuation period as shown, the short period component and the middle period component are significantly suppressed. This effect tends to be remarkable as the volume of the buffer tank increases with respect to the supply flow rate of low calorie gas. When the fluctuation range of the intrinsic fluctuation is small, it is effective even if the volume of the buffer tank is made small from the viewpoint of economy.

FIG. 5 shows the attenuation state of the calorie fluctuation when the low-calorie gas flow rate is 500,000 Nm 3 / hr and the volume of the buffer tank 10 is 100,000 m 3, which is half of the above. The calorie fluctuation in this case is also suppressed by the buffer tank 10 in the range of 1,700 mW / Nm 3 to 2,040 mW / Nm 3, and the variation range is about ± 9% of the average value (1,970 mW / Nm 3).

FIG. 6 shows the attenuation state of calorie fluctuations when the volume of the buffer tank 10 is 50,000 m 3 in a facility where low calorie gas is supplied at a flow rate of 200,000 Nm 3 / hr. The calorie fluctuation in this case is also suppressed by the buffer tank 10 in the range from 1,740 kPa / Nm 3 to 2,010 kPa / Nm 3, and the variation range is about ± 7.2% of the average value (1,875 kPa / Nm 3).

Although not shown, in a facility in which low-calorie gas is supplied at a flow rate of 200,000 Nm 3 / hr as described above, when the volume of the buffer tank 10 is set to 25,000 m 3, which is half of the above, the variation range is an average value (1,875 kPa / Nm 3). ) Is about ± 12%.

As shown in FIG. 7, in a facility in which low-calorie gas is supplied at a flow rate of 200,000 Nm 3 / hr, two buffer tanks 10 having a volume of 25,000 m 3 are provided in parallel, and both are used during normal operation. In addition, it is conceivable that only one tank is used only for abnormal situations such as periodical inspection or poor operation.

Thus, only the buffer tank is provided, and the calorie fluctuation of the low calorie gas is largely suppressed without active control. As a result, the control of mixing the waste nitrogen and the inert gas downstream is very easy. For example, when the calorie fluctuation range of the fuel gas of the gas turbine 2 is set to +/- 10% of the reference calorie value (average value), the average value of the calorie fluctuating downstream of the buffer tank is the gas turbine 2 In order to coincide with the reference calorie value set in the above, a buffer tank having a volume corresponding to the standard is provided, and a constant ratio of waste nitrogen is supplied from the downstream side. Regarding the supply operation of the waste nitrogen, it is not necessary to consider an aspect of calorie fluctuation of low calorie gas.

In extreme cases, a waste nitrogen supply facility or an inert gas supply facility is necessary if the average value of the calorie fluctuations of the low calorie gas after passing through the buffer tank 10 is approximately equal to the reference calorie value set in the gas turbine 2. Disappear. Even when both facilities are provided, the facility may be operated with the stop valve 29 of the waste nitrogen supply pipe 4 of FIG. 1 and the stop valve 29 of the supply pipe 38 of FIG. 2 closed. Naturally, when the calorie fluctuation of the low-calorie gas generated is not large, the installation of the buffer tank is not necessary, and the waste nitrogen supply facility or the inert gas supply facility can be sufficiently coped with.

Another buffer tank 42 is shown in FIG. 8. Since this buffer tank 42 is used for the conventional gas turbine installation, it is contained in the apparatus 40 which monitors gas volume balance. The gas amount balance monitoring device 40 is for balancing the low calorie gas amount sent from the upstream side with the consumption gas amount required by the gas turbine. When there is a fluctuation in the amount of supply gas or a load fluctuation of the gas turbine, it is necessary to balance the supply amount and the consumption amount. When the supply is unexpectedly excessive, the gas is dissipated to the atmosphere. When the supply is insufficient, the gas turbine may be lowered or some operations may be stopped.

The gas amount balance monitoring device 40 is hermetically sealed to a tank 42 whose outlet 42b is connected to the low-calorie gas supply pipe 3 by a communication tube 41, and an upper end opening of the tank 42. In addition, the lid member 43 provided with the sealant so that the tank can be moved up and down, and the adjustment weight 44 provided, for example in the lid member 43 are provided. The lid member 43 is moved up and down in the tank by the balance between the weight of the weight 44 and the total amount of pushing force due to atmospheric pressure, and the pushing force due to the internal pressure of the tank 42. Move. Therefore, the lid member 43 moves up and down in response to the balance change of the supply amount and the consumption amount of the low calorie gas. While monitoring the vertical movement of the lid member 43, measures such as air dissipation of the gas and reduction of the turbine load are taken.

The buffer tank of FIG. 8 uses the gas amount balance monitoring device 40 to suppress calorie fluctuations. The upstream side inlet pipe 45 which connects the upstream side and the inlet 42a of a tank to the said tank 42 rather than the connection position with the communication pipe 41 in the low-calorie gas supply piping 3 besides the said communication pipe 41 newly. ) Is connected. The upstream side inlet pipe 45 is provided with a fan 39 for sending low-calorie gas to the tank 42. Since the upstream side inlet pipe 45 is connected to the upstream side of the low-calorie gas supply pipe 3 rather than the communication pipe 41, the said fan 39 can also be abbreviate | omitted by piping design which considered pressure loss. The same applies to the upstream inlet pipe 45 shown in FIGS. 9 and 13. A part of the low calorie gas supplied flows into the tank 42 through the upstream inlet pipe 45, and the low calorie gas is mixed in the tank 42, and the same amount of gas is supplied through the communication pipe 41 into the tank 42. ) Is returned to the low-calorie gas supply pipe 3. In this case, the communication pipe 41 is also called an outlet pipe. The buffer tank 42 is connected to the upstream side inlet pipe 45 and the communication pipe 41 constituting the bypass pipe of the low calorie gas supply pipe 3, that is, to the low calorie gas supply pipe 3. Are installed in parallel.

Also by the buffer tank 42, the low-calorie gas sent through the upstream inlet piping 45 is mixed in the buffer tank similarly to the buffer tank 10 mentioned above. As a result, the calorie fluctuation range of the low-calorie gas exiting from the outlet 42b of the buffer tank 42 is reduced, and the fluctuation rate is lowered. That is, the calorie fluctuation is greatly alleviated (suppressed).

In addition, in the tank 42, a stirring device 51 such as a fan is provided to agitate the gas. This is to promote the mixing of the gas in the tank, thereby realizing more effective suppression of calorie fluctuation. As an installation form of the stirring apparatus 51, it is preferable from a viewpoint of the effective mixing of gas that it is installed in the vicinity of the outlet 42b in the attitude | position which can flow gas from the vicinity of the outlet 42b of a tank toward a tank inside. The stirring device 51 is not limited to the tank 42 of FIG. 8, but can also be provided for the tanks 10, 42, 47 shown in other drawings and other tanks capable of exhibiting a calorie suppressing effect. . Moreover, it is preferable to provide the electric motor 51a etc. as a rotational drive of the stirring apparatus 51 in the exterior of a tank.

9 shows another gas amount balance monitoring device 46 which can be used as calorie fluctuation suppressing means. The gas amount balance monitoring device 46 has a more economical configuration and includes a gas-tight tank 47 in communication with the low-calorie gas supply pipe 3 by the communication pipe 41. The pressure detection apparatus 48 is provided in the tank 47, and the internal pressure of the tank 47 is always monitored. When the detection pressure reaches the upper limit region, the control device 100 issues a command to increase the gas consumption in the facility, and balances the supply and demand of the gas. The other structure is similar to the above-described apparatus 40 (FIG. 8), and the upstream inlet piping 45 is connected to the inlet 47a of the tank 47, and the communication pipe 41 is connected to the outlet 47b. Connected. The tank 47 can also be sufficiently used as calorie fluctuation suppressing means.

FIG. 10 shows the volume of the tank 42 (47) shown in FIG. 8 or 9 as 200,000 m 3 in a facility in which calorie fluctuating low calorie gas is supplied at a flow rate of 500,000 Nm 3 / hr. By the following, the calorie fluctuation in the case of sending 200,000 Nm 3 / hr of gas to the tank 42 (47) among the flow rates of 500,000 Nm 3 / hr is shown. The curve shown by the dotted line in the figure shows the calorie variation (unique variation) of the low-calorie gas sent from the direct reduction steelmaking facility (S). This is the actual measurement sample described above. The curve indicated by the dashed line indicates the simulation result of the calorie fluctuation (transient fluctuation) of the low calorie gas passing through the tank 42 and passing through the communication tube 41. The curve shown by the solid line shows the calorie fluctuation (post-inhibition fluctuation) of the gas which reaches the mixer 5 via the low-calorie gas supply piping 3 part downstream from the communication pipe 41. As described above, the calorie of the low calorie gas before entering the tank 42 (47) has a fluctuation range of about ± 21% of the average value (1,945 kPa / Nm 3). By the way, the calorie change of the gas after joining the low-calorie gas supply pipe 3 from the tank 42 (47) through the communication pipe 41 is from 1,690 kPa / Nm 3 to 2,100 kPa / Nm 3, and the variation range is an average value ( 1,895 kV / Nm 3) is suppressed to about ± 11%. This figure is an example.

In this manner, it is also possible to suppress the gas calorie fluctuation by using an existing facility including the tank 42 (47). In addition, it is possible to easily dilute the low calorie gas with the waste nitrogen downstream. In FIG. 8 and FIG. 9, the upstream inlet pipe 45 that sends the low calorie gas to the tank 42 (47) is connected to the upstream side of the outlet pipe 41 in the low calorie gas supply pipe 3. It is not limited to such a structure in particular, You may connect to the downstream side rather than the outlet piping 41 (refer FIG. 14). In addition, both pipes 41 and 45 may be provided in multiple lines.

The buffer tank 42 shown in FIG. 11 is a buffer tank 42 for the gas amount balance monitoring apparatus 40 similar to that shown in FIG. The difference is in the form of piping connecting the low calorie gas supply pipe 3. The piping form of FIG. 11 removes the part from the connection part with the upstream side inlet piping 45 to the connection part with the communication pipe 41 in the low-calorie gas supply piping 3 of FIG. The fan 39 on the side inlet pipe 45 is removed. That is, the low calorie gas supply pipe 3 on the upstream side is connected to the inlet 42a, and the low calorie gas supply pipe 3 on the downstream side is connected to the outlet 42b. In other words, the buffer tank 10 shown in FIG. 1 and FIG. 2 was replaced with the tank 42 for the gas amount balance monitoring apparatus 40. Such piping is a form which can be easily retrofitted when the existing gas amount balance monitoring device 40 also serves as a gas calorie fluctuation suppressing device.

12 shows other calorie fluctuation suppressing means. This means is a return pipe 49 for returning a part of the low calorie gas to the upstream side of the low calorie gas supply pipe 3 provided in the low calorie gas supply pipe 3. The return pipe 49 is provided with a fan 39 for pumping low calorie gas upstream. Although the return piping 49 shown is comprised so that it may branch from one suction part to the branch pipe 49a of several lines, and will return to the previous low calorie gas supply piping 3, Even if it is comprised by the return piping of one line, good. Moreover, you may provide one line of return piping in the several different site | part of the low calorie gas supply piping 3, respectively.

Also by this means, the low-calorie gas is mixed with the low-calorie gas newly supplied at the time of returning upstream of the low-calorie gas supply pipe 3, and the calorie fluctuation is alleviated. In order to increase this effect, the length of the return pipe 49 may be increased, and the volume ratio of the return gas amount to the supply gas amount may be increased.

FIG. 13 also shows a buffer tank 42 provided in parallel with respect to the low calorie gas supply pipe 3 in the same manner as the tank of FIG. 8. As shown, between the tank 42 and the low-calorie gas supply piping 3, the upstream inlet piping 45 provided with the fan 39, and the said communication pipe 41 as an outlet piping are connected. That is, the upstream inlet pipe 45 is connected to the inlet 42a of the tank 42, and the outlet pipe 41 is connected to the outlet 42b. However, a new inlet 50a is formed in the tank 42, and a downstream inlet pipe connected to the inlet 50a is downstream from the connection portion with the outlet pipe 41 in the low-calorie gas supply pipe 3. 50 is connected. The downstream side inlet pipe 50 is provided with a fan 39 for sending low-calorie gas to the tank 42. As shown, the connection positions (inlets 42a and 50a) of the upstream side inlet pipe 45 and the downstream side inlet pipe 50 to the tank 42 are close to each other.

According to this structure, a part of low-calorie gas is pumped to the tank 42 through the upstream side inlet_pipe from the upstream of the low-calorie gas supply piping 3, and at the same time from the downstream side of the low-calorie gas supply piping 3 A part of low-calorie gas is conveyed through the downstream side inlet piping 50, it mixes, and it flows out from the outlet 42b to a communication pipe. As a result, since a part of the low-calorie gas whose calorie fluctuation was suppressed circulates, mixing for a long time in the tank is realized. The longer the length of the downstream inlet pipe 50 is, the longer the residence time of the gas to be mixed becomes, and more preferable mixing is realized. The downstream inlet pipe 50 is connected to the inlet 50a of the tank 42 from the downstream side of the low calorie gas supply pipe 3, but from the downstream side, the inlet pipe of the low calorie gas supply pipe 3 ( You may connect to the upstream rather than the connection part with 45).

14 also shows a buffer tank 42 installed in parallel with the low calorie gas supply pipe 3. As illustrated, the communication pipe 41 and the downstream inlet pipe 50 as the outlet pipe are connected between the tank 42 and the low calorie gas supply pipe 3. The downstream side inlet pipe 50 is provided with a fan 39 for sending low-calorie gas to the tank 42.

According to such a structure, even if the downstream inlet piping 50 is connected to the downstream side rather than the connection part with the communication pipe 41 in the low calorie gas supply piping 3, the low calorie gas will be set in the downstream inlet piping ( It is sent into the tank 42 through 50, mixes, and flows out from the outlet 42b to the communication pipe | tube. As a result, an effective mixing is achieved because a part of the low calorie gas whose calorie fluctuation is suppressed circulates. As the length of the downstream inlet pipe 50 is increased, the mixing over a longer time in the tank is realized.

The tank 42 shown in FIG. 15 has two types of inlets 42a and 50a. The upstream low calorie gas supply pipe 3 is connected to one inlet 42a, and the downstream low calorie gas supply pipe 3 is connected to the outlet 42b, and the downstream low calorie gas is connected to the other inlet 52a. The return pipe 52 connected to the supply pipe 3 is connected. The two inlets 42a and 52a are formed in close proximity. The return pipe 52 is provided with a fan 39 for sending low-calorie gas to the tank.

According to this structure, since some of the low-calorie gas whose calorie fluctuation was suppressed in the tank 31 was returned to the tank 42 again, and mixed again, more preferable mixing is realized. The longer the return pipe 52 is, the longer the residence time of the gas to be mixed. The return pipe 52 is connected to the inlet 52a of the tank 42 from the downstream side of the low calorie gas supply pipe 3, but from the downstream side, the return pipe 52 is located upstream of the tank in the low calorie gas supply pipe 3. You may connect.

Although the by-product gas generated by the direct reduction iron-making method was illustrated as the low-calorie gas to be used, it is not limited to this. Examples of the low-calorie gas include furnace gas (BFG), converter gas (LDG), coal bed gas (coal mine gas, denoted as CMG) included in the coal bed, and by-product gas generated by the melt reduction steelmaking method, and GTL ( Tail gas generated from gas-to-liquids process, by-product gas generated by oil refining process from oil sand, gas generated by waste incineration using plasma, and household waste Low-calorie gas, such as by-product gas generated by chemical reaction of methane gas (Landfill gas) generated during the fermentation and decomposition of general wastes in landfills, and other similar raw materials. Of course, the gas alone, as well as a mixture of a plurality of dissimilar gases, such as a mixed gas of BFG and LDG, also includes a gas whose calorific value is about 12 MJ / Nm 3 or less.

According to the present invention, by keeping a large amount of low calorie gas whose calorie changes from time to time and diluting with waste nitrogen of low oxygen concentration which is easy to collect, it is possible to suppress abnormal rise in combustion temperature and to continue stable combustion. have. That is, the said effect is acquired by low installation cost and operation cost. Furthermore, the nitrogen gas generated in the oxygen production plant etc. which was conventionally discarded can be utilized effectively.

Claims (22)

delete delete delete A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; A calorific value detecting device provided in the fuel gas supply passage for detecting the calorific value of the gas; And a control device for controlling the waste nitrogen supply operation by the waste nitrogen supply passage based on the detection result of the calorific value detection device, An inert gas supply passage for supplying an inert gas to the fuel gas supply passage; The control device is configured to control the inert gas supply operation by the inert gas supply passage on the basis of the detection result of the calorific value detection device in a state where the waste nitrogen supply to the fuel gas supply passage by the waste nitrogen supply passage is performed. There is a fuel gas supply facility characterized in that. delete A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; It is provided in the fuel gas supply passage, and provided with a calorific value detecting device for detecting the calorific value in the gas, In the waste nitrogen supply passage, an oxygen concentration fluctuation suppression tank for temporarily storing waste nitrogen supplied from at least one of an oxygen production plant and a nitrogen production plant is provided, The oxygen concentration fluctuation suppressing tank has an inlet and an outlet, and the inlet is connected with an upstream side of the waste nitrogen supply passage, and the outlet is connected with a downstream side of the waste nitrogen supply passage. . delete A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; It is provided in the fuel gas supply passage, and provided with a calorific value detecting device for detecting the calorific value in the gas, In the fuel gas supply passage, a tank for temporarily storing fuel gas is provided, The tank has an outlet and two types of gas inlets, A downstream side of the fuel gas supply passage is connected to the outlet; An upstream side of the fuel gas supply passage is connected to one gas inlet, A return passage is connected between the other gas inlet and the downstream side of the fuel gas supply passage, And a gas feeding device for feeding fuel gas toward the tank in the return passage. A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; It is provided in the fuel gas supply passage, and provided with a calorific value detecting device for detecting the calorific value in the gas, In the fuel gas supply passage, a tank for temporarily storing fuel gas is provided, The tank has an inlet and an outlet, the inlet is connected to an upstream side of the fuel gas supply passage, the outlet is connected to a downstream side of the fuel gas supply passage, A feedback passage is connected between the fuel gas supply passage upstream from the tank and the fuel gas supply passage downstream from the tank; And a gas feeding device for feeding fuel gas toward the fuel gas supply passage on the upstream side of the tank in the return passage. A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; It is provided in the fuel gas supply passage, and provided with a calorific value detecting device for detecting the calorific value in the gas, In the fuel gas supply passage, tanks for temporarily storing fuel gas are provided in parallel, Between the fuel gas supply passage and the tank, an upstream side for sending fuel gas to the tank from an upstream side from an outlet passage for returning fuel gas from the tank to the fuel gas supply passage and an outlet passage in the fuel gas supply passage. A fuel gas supply facility, characterized in that the inlet passage is provided. A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; It is provided in the fuel gas supply passage, and provided with a calorific value detecting device for detecting the calorific value in the gas, In the fuel gas supply passage, tanks for temporarily storing fuel gas are provided in parallel, Between the fuel gas supply passage and the tank, a downstream side for sending fuel gas to the tank from a downstream side than an outlet passage for returning fuel gas from the tank to the fuel gas supply passage and an outlet passage in the fuel gas supply passage. The entrance passage is installed, And a gas pressure feeding device for feeding fuel gas toward the tank in the downstream inlet passage. The method of claim 10, A return passage is connected between the downstream side of the connection point with the outlet passage in the fuel gas supply passage and the upstream side of the connection point with the inlet passage in the fuel gas supply passage, And a gas feeding device for feeding fuel gas toward the upstream fuel gas supply passage in the return passage. The method of claim 10, A fuel gas supply facility, characterized in that the stirring device for stirring the gas inside the tank is installed. A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; It is provided in the fuel gas supply passage, and provided with a calorific value detecting device for detecting the calorific value in the gas, And a return passage connected between an upstream portion and a downstream portion in the fuel gas supply passage, And a gas feeding device for feeding a portion of the fuel gas flowing through the fuel gas supply passage from the downstream portion of the fuel gas supply passage toward the upstream portion in the return passage. Gas turbine, And a fuel gas supply facility for supplying gas as fuel to the gas turbine, Said fuel gas supply facility consists of a fuel gas supply facility as described in any one of Claims 4, 6, 8-10, 12, 14, The gas turbine characterized by the above-mentioned. equipment. delete When supplying the fuel gas to the gas turbine, the mixing step of mixing the fuel gas by passing through the tank for temporarily storing the fuel gas, A calorie measurement step of measuring a calorific value of fuel gas after mixing by the tank; A waste nitrogen mixing step of mixing waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant as fuel for dilution when the measurement result exceeds a set allowable calorie value, The tank has an inlet through which the fuel gas is introduced, and an outlet through which the fuel gas is discharged. And incorporating an inert gas into the fuel gas when it is determined that the calorific value measurement result does not fall below a set allowable calorie value even by waste nitrogen supply. Gas turbine, And a fuel gas supply facility for supplying gas as fuel to the gas turbine, The fuel gas supply facility comprises the fuel gas supply facility according to claim 11. Gas turbine, And a fuel gas supply facility for supplying gas as fuel to the gas turbine, The fuel gas supply equipment is the fuel gas supply equipment according to claim 10, A gas turbine installation, characterized in that a stirring device for stirring the gas inside the tank is provided. delete A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; A calorific value detecting device provided in the fuel gas supply passage for detecting the calorific value of the gas; A tank provided upstream from the waste nitrogen supply passage connecting portion of the fuel gas supply passage to temporarily store and mix the fuel gas; And a control device for controlling the waste nitrogen supply operation by the waste nitrogen supply passage based on the calorific value of the fuel gas after mixing by the tank detected by the calorific value detection device, The tank has an inlet and an outlet, the inlet is connected to an upstream side of the fuel gas supply passage, the outlet is connected to a downstream side of the fuel gas supply passage, A fuel gas supply facility, characterized in that the stirring device for stirring the gas inside the tank is installed. Gas turbine, A fuel gas supply device for supplying gas as fuel to the gas turbine; A stirring device for agitating the gas inside the tank, The fuel gas supply facility, A fuel gas supply passage for supplying gas to the gas turbine as fuel; A waste nitrogen supply passage connected to the fuel gas supply passage for supplying waste nitrogen generated in at least one of an oxygen production plant and a nitrogen production plant to the fuel gas supply passage; A calorific value detecting device provided in the fuel gas supply passage for detecting the calorific value of the gas; A tank provided upstream from the waste nitrogen supply passage connecting portion of the fuel gas supply passage to temporarily store and mix the fuel gas; And a control device for controlling the waste nitrogen supply operation by the waste nitrogen supply passage based on the calorific value of the fuel gas after mixing by the tank detected by the calorific value detection device, The tank has an inlet and an outlet, the inlet is connected to an upstream side of the fuel gas supply passage, and the outlet is connected to a downstream side of the fuel gas supply passage.

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