JPH0696981B2 - Heating device and control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention introduces the exhaust gas of a gas turbine provided outside a heating furnace into the furnace, and uses the heat contained in the exhaust gas and the combustion heat of the fuel supplied into the heating furnace together. And a method of controlling the heating device.

[0002]

2. Description of the Related Art Generally, these heating furnaces have a built-in tube to be heated such as a serpentine tube type or a tube plate type, and are used for supplying and heating raw materials such as naphtha and water to these heated tubes. It is a thing. In these heating devices, for example, when naphtha is pyrolyzed to produce ethylene or hydrogen, a large amount of raw material flowing through the heated pipe in a short time of about 0.1 to 0.3 seconds is 400 to 900 ° C. It is necessary to heat up to the high temperature.

Since the fuel consumption for this heating is enormous,
Many energy-saving technologies have been adopted so far, and as a particularly significant investment effect, a gas turbine is attached to the heating furnace, the high-temperature exhaust gas is introduced into the heating furnace, and the fuel supplied to the heating furnace is supplied. A method of utilizing it with the heat of combustion has been proposed.

However, the gas turbines that have been introduced so far are all for power generation for general industry or for combined heat and power supply. These onshore gas turbines
It is highly reliable and can be operated continuously for a long time.
There was a problem that it was large and required a vast installation floor area. Further, the thermal efficiency is generally 30% or less, and further improvement of the thermal efficiency is desired for the promotion of comprehensive energy saving.

Generally, a gas turbine for an aircraft engine is designed to be small and lightweight so that it can be mounted on an aircraft, and particularly high efficiency can be obtained. The thermal efficiency can be improved and the required floor area can be saved.

However, gas turbines for aircraft are
Not designed for long-term continuous operation,
Also, it is significantly lighter than that for general industry, but this is not necessarily convenient for general industry in all respects. Since it took too short a time to stop rotating, it was impossible to immediately convert it into an industrial one.

That is, in this type of heating device, in order to make up for the interruption of the heat supply from the gas turbine when the gas turbine is stopped unnecessarily, the supply amount of fuel and air to the heating furnace is increased to It is necessary to significantly change the combustion state of No. 1 to keep the amount of heat supplied to the object to be heated constant or to decrease the amount of object to be heated according to the fluctuation of the amount of heat supplied to the heating furnace. In any case, the gas turbine for an aircraft engine has a small inertia in the rotating part, and when it is stopped, the flow rate of the high temperature exhaust gas from the gas turbine sharply decreases and is interrupted within a short time. It was difficult to keep the temperature distribution in the heating furnace stable following the rapid changes.

[0008] Usually, such an industrial heating furnace is combined with various plants provided on the downstream side thereof and integrated as a whole, so that the supply amount of the object to be heated is reduced. This method cannot be adopted because it involves fluctuations in the amount of products supplied to those plants and has a great impact on the entire plant. Therefore, it is necessary to greatly increase the supply amount of fuel and air.
This is the control of the air supply amount. This is because the fuel supply amount can be switched relatively quickly, but it takes a considerable time to increase the air supply amount.

For example, an emergency blower is installed to perform such control, and the emergency blower is started to supply air to the heating furnace at the moment when the gas turbine for the aircraft engine is urgently stopped. Even if you try, the time required for the blower to reach the rated speed, and its wind pressure and air flow rate to reach the rated value is usually much longer than the time until the supply of high-temperature exhaust gas from the gas turbine is interrupted. Since the air supply to the heating furnace is not in time, and the difference between the air supplied from the blower and the physical state of the exhaust gas supplied from the gas turbine (for example, temperature, oxygen concentration, etc.) is too large. However, the above-mentioned method has a great influence on the combustion state in the heating furnace, so that there is a problem that incomplete combustion or misfire of the fuel occurs and the quality of the product is impaired.

As another means, as an always operating blower, one having a larger capacity than that required for normal operation is installed.
Normally, the blower is operated at low speed, or the flow path of the blower is throttled with a valve or the like so that air is constantly supplied to the heating furnace at a low flow rate below the rated value, and the gas turbine is There is a method to increase the flow rate of the blower from the moment of an emergency stop, but doing so increases the equipment cost and the operating cost during normal operation, and even in this case, switching the blower requires a considerable time, Since there is a large difference in the physical state between the air supplied from the blower and the exhaust gas supplied from the gas turbine, it is inevitable that a large fluctuation in the temperature distribution within the heating furnace will occur, and this can be restored to a normal state within a short time. It was difficult to recover.

If the temperature distribution of the heating furnace fluctuates greatly, the state of the products from the heating furnace (for example, constituents, amount, temperature, pressure) also fluctuates greatly, and this also affects downstream processes. , The entire plant may fall into a dangerous state and an accident or disaster may occur.

Due to fluctuations before and after the emergency stop of the gas turbine,
What has a particularly great influence is the outlet temperature of the heated tube built into the heating furnace. Since the temperature of the air sent from the blower is much lower than the temperature of the exhaust gas supplied from the gas turbine, the conventional method causes the temperature inside the heating furnace to temporarily drop after the gas turbine is shut down. Inevitably, if the temperature in the heating furnace is lowered, the outlet temperature of the heated pipe contained in the heating furnace is also lowered, so that the composition of the heated product and the like greatly fluctuate.

If the flow rate of the raw material supplied to the tube to be heated is reduced in order to avoid this, the amount of the product from the heating furnace will be reduced, and the effect will reach the downstream plant. Due to the above-mentioned circumstances, any known control method has a great influence not only on the operation of the heating furnace but also on the operation of the downstream plant. Further, even in large boilers today, the amount of water retained in the can is extremely small. Therefore, when the exhaust heat of the gas turbine for aircraft engines is used, the same problem as described above occurs.

[0014]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a gas turbine combined heating furnace used in a production apparatus for ethylene, hydrogen, etc., or a large-scale boiler etc. It is intended to provide a technique for utilizing a high-efficiency gas turbine for an aircraft engine that could not be used because it was difficult to deal with, thereby further saving energy in these energy consuming facilities.

[0015]

The above object of the present invention is to:
A heating furnace equipped with a fuel combustion apparatus and a heated pipe through which a fluid to be heated flows, an apparatus for introducing high temperature exhaust gas of a gas turbine provided outside the heating furnace into the heating furnace, and a fuel combustion apparatus for the heating furnace Device for supplying fuel to the heating furnace, a blower for supplying air into the heating furnace, a device for controlling the air supply amount to the heating furnace according to the fuel supply amount to the heating furnace, and the exhaust gas of the gas turbine to the heating furnace. The apparatus includes a device for controlling the supply amount and a device for controlling the fuel supply amount to the heating furnace, and a device for controlling the fuel supply amount to control the temperature of the product flowing out of the heated pipe. In a device that heats a fluid flowing through a heated pipe by using combustion heat generated in a furnace and heat of a high temperature exhaust gas of a gas turbine, the gas turbine is a gas turbine for an aircraft engine, and an exhaust gas supply control device Gas turbine stopped In addition, the exhaust gas cutoff valve for closing the exhaust gas distribution pipe to the heating furnace, the product temperature control device, when the gas turbine is stopped, equipped with a means for setting a temperature set value higher than the value before the stop for a certain period of time. , The air supply control device corresponds to the fuel supply amount indicated by the fuel indicating controller of the product temperature control device. This is achieved by the above heating device characterized by controlling the flow rate of air supplied to the heating furnace.

As a gas turbine for the aircraft engine, a high temperature exhaust gas of 400 to 700 ° C. is generated, and when the high temperature exhaust gas is stopped, the time required for the flow rate of the high temperature exhaust gas to halve from the normal flow rate is 0.5 seconds. It is recommended to use the one for 20 seconds or more and more preferably for 2 seconds or more and 15 seconds or less.

Further, the above object is to control the above heating device, when the gas turbine is stopped unintentionally,
In order to maintain a constant product quality without reducing the supply of raw material, the trip detection controller detects the gas turbine stoppage and sends a trip detection signal, and the exhaust gas from the gas turbine to the heating furnace. Close the supply pipeline, fully open the air flow control valve provided in the pipeline that supplies air to the heating furnace, and set the product temperature controller to a temperature higher than the value immediately before the gas turbine was stopped. And the product temperature control device controls the opening of the fuel control valve in order to increase the fuel supply amount to the heating furnace in response to the set temperature increased by the step described in the preceding paragraph. In order to maintain the air flow rate required for the combustion of the fuel corresponding to the fuel supply amount indicated by the fuel control meter, the step for controlling the air supply flow rate control device to the heating furnace And the step of returning the set temperature of the product temperature control device to the original set value after the elapse of a predetermined time, and the set temperature returned to the normal value in the step described in the preceding paragraph. , The step of controlling the fuel supply amount to the heating furnace by the product temperature control device, and to maintain the air flow rate required for combustion of the fuel corresponding to the fuel supply amount indicated by the fuel control meter, This is achieved by controlling the temperature of the product at the outlet of the heated pipe to a constant value by a control method comprising the step of causing the supply air flow rate control device to perform a normal control operation.

[0018]

According to the present invention, even if a gas turbine for an aircraft engine is used, emergency control of fuel and air can be surely performed in response to the stop of the gas turbine. Also, since the temperature of the product at the outlet can be controlled to be constant without changing the supply amount of the raw material to the heated pipe, the quality and amount of the product can be constantly maintained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the configuration of a heating device that can be used as, for example, a naphtha cracking furnace for ethylene production, FIG. 2 is a graph showing stop characteristics of a gas turbine for aircraft engines, and FIG. 3 is shown in FIG. 7 is a graph showing changes in the indicated value of the indicating controller.

In FIG. 1, 1 is a heating furnace, 2 is a gas turbine exhaust gas supply device, 3 is a device for controlling the air supply amount to the heating furnace 1, and 4 is a supply amount of the exhaust gas supplied to the heating furnace 1. A device, 5 is a device for controlling the temperature of the product, 6 is a blower for supplying air to the heating furnace 1, 7 is a fuel supply device,
Reference numeral 8 is a raw material supply device, and 9 is a plant that receives a product.

In an actual plant, a large number of heating furnaces are provided in parallel for one gas turbine, but only one set is shown here.

The heating furnace 1 includes a furnace body 10 and a fuel combustion device 1.
1, a heated tube 12, a chimney 13, an exhaust fan 14, a drive motor 15 for the same, an exhaust damper 16, and heats and decomposes raw materials such as naphtha supplied from the raw material supply device 8 into the heated tube 12. , The degradation product is delivered, and the pipeline 9
1 to the receiving plant 9.

The gas turbine exhaust gas supply device 2 includes a gas turbine 20 for an aircraft engine, a generator 21, a trip detector 22 that detects the stoppage of the gas turbine 20 and sends a detection signal thereof, a chimney 23, and an exhaust gas pressure control device 24. , Exhaust gas supply pipe 25, exhaust gas distribution pipe 26, exhaust gas discharge pipe 27
And an exhaust gas oxygen meter 28, and the exhaust gas generated during power generation is supplied to the heating furnace 1 through a supply pipe 25 and a distribution pipe 26.

Thus, this gas turbine 20 is for an aircraft engine, and its exhaust gas temperature is 400 to 700 °.
C, the time until the exhaust gas flow rate is reduced from the normal flow rate to half when stopped is used for 0.5 seconds or more and 20 seconds or less. A more desirable gas turbine rotation speed half time is 2
It is at least 15 seconds but not more than 2 seconds. This rotation speed half time is 0.5
In seconds, it becomes difficult to control even by the present invention,
If the rotation half-time is 20 seconds or more, the downsizing and weight saving are not sufficient, and there is a problem in terms of thermal efficiency.

The air supply amount control device 3 comprises an air flow rate calculation control device 31, an air flow rate indicating controller 32 for detecting the air flow rate of the blower 6, and an air flow rate adjusting valve 33. Information such as the exhaust gas supply amount, exhaust gas oxygen concentration, and fuel supply amount to the furnace 1 is received, the required air amount is calculated, the opening of the air flow rate control valve 33 is adjusted, and the optimum amount of air is supplied to the heating furnace 1. Supply.

The exhaust gas supply amount control device 4 includes an exhaust gas flow rate calculation control device 41, an exhaust gas flow rate instruction controller 42, an exhaust gas flow rate control valve 43, an exhaust gas cutoff valve 44, and the like, and controls the opening degree of the exhaust gas flow rate control valve 43. The flow rate supplied to the heating furnace 1 is maintained at a predetermined value.

The product temperature control device 5 comprises a temperature calculation control device 51, a temperature indicating controller 52 provided at the outlet of the heated pipe 12, a fuel supply amount control device 53, a fuel cutoff valve 54, and the like, and the fuel flow rate control is performed. The device 53 includes a fuel flow rate indicator controller 531 and a fuel flow rate control valve 5 provided in the fuel supply pipe 71.
It consists of 32. The product temperature control device 5 controls the amount of fuel supplied to the heating furnace 1 so that the temperature of the product delivered from the heated pipe 12 is kept constant.

When the heating device is used as, for example, an ethylene production device, a petroleum fraction such as naphtha, ethane and liquefied petroleum gas is usually used as a raw material, and steam as a diluent is added thereto by weight. The mixture is mixed at a ratio of 0.3 to 0.5 and supplied to the heated pipe 12.

The mixture supplied to the heated tube 12 is 0.
Remains in the heated tube 2 for 1 to 0.3 seconds, during which 750
The reaction product gas is heated to ˜900 ° C. and pyrolyzed, and the reaction product gas is received by the downstream plant 9 through the passage 91.

Although only one fuel combustion device 11 is shown in the drawing, a plurality of fuel combustion devices 11 are installed on the side wall portion and floor surface of the heating passage 1, and these are respectively provided with fluid fuel, combustion air, and combustion air. Exhaust gas from the gas turbine is being supplied.

Generally, the operation control of this type of cracking furnace is mainly to control the supply amounts of raw materials and steam and to control the temperature of the cracked products. Of these, the former is performed by a flow rate controller (not shown) provided in each raw material supply pipe, and the latter is fuel supplied to the fuel combustion device 11 by the fuel supply amount control device 53 provided in the fuel supply pipe 71. To adjust.

A gas turbine 20 for an aircraft jet engine drives a generator 21 using the gas turbine 20 as a drive source, and the gas turbine 20 is a trip detector that operates when the gas turbine 20 is untimely stopped due to a failure or the like. 22 is provided. The exhaust gas discharge port of the gas turbine 20 is connected to a pipe 27 to the chimney 23 and a pipe 25 for supplying the exhaust gas to the heating furnace 1.

Each heating furnace 1 is provided with a blower 6, and the air blown by the blower 6 is sucked by a suction pipe 6
1. Through the discharge pipe 62, it merges with the exhaust gas sent from the gas turbine 20, and is sent to the fuel combustion device 11. The high temperature exhaust gas from the gas turbine 20 is distributed to each heating furnace 1 through the exhaust gas supply pipe 25 and the exhaust gas distribution pipe 26 to each cracking furnace, and the oxygen supply amount by the exhaust gas is the fuel supplied to each heating furnace 1. It is desirable that the amount of oxygen be equal to or less than the amount of oxygen required for combustion, and the blower 6 replenish the shortage.

The arithmetic and control unit 31, which combines the information signals from these control devices to comprehensively perform arithmetic control,
It is recommended to use a distributed direct digital control computer as 41 and 51. In this case, the control system of the arithmetic and control unit will be the following three systems. First system: Air supply amount calculation control system Oxygen contained in high temperature exhaust gas from the gas turbine 20,
The amount of air supplied to the heating furnace 1 is optimally controlled by comprehensively adjusting the oxygen contained in the air sent from the blower 6 together. Second system: Gas turbine exhaust gas supply amount calculation control system The flow rate of exhaust gas supplied from the gas turbine 20 to the heating furnace 1 is adjusted. Third system: product temperature calculation control system The temperature of the product sent from the heated pipe 12 is kept constant. At the time of an emergency stop of the gas turbine 20, the set value of the temperature controller 52 is set according to a program prepared in advance in order to keep the supply amount of the raw material and the outlet temperature of the heated tube 12 of the heating furnace 1, that is, the product temperature constant. Is raised for a certain period of time to a value higher than the set value at the time of stop, and is returned to the original value after a predetermined time has elapsed.

Next, a normal control operation of this heating device will be described. (A) Startup of heating furnace During the operation stop of the heating furnace 1, the exhaust gas flow rate control valve 43 and the exhaust gas cutoff valve 44 provided in the exhaust gas distribution pipe 26 are fully closed, and the heating furnace 1 and the gas turbine 20 are connected. The communication line is blocked. In this state, the fuel combustion device 11 is ignited, the temperature of the heating furnace 1 is raised, and the starting operation for using the heating furnace 1 as a cracking furnace is performed such as starting the supply of raw materials. Until the steady operation, the air for fuel combustion is not supplied from the gas turbine 20, but is supplied only by the blower 6.

(B) Startup of gas turbine Exhaust gas flow rate control valve 4 provided in the exhaust gas distribution pipe 26 of the heating furnace
3 and the degree of opening of the emergency cutoff valve 44 are 0, the exhaust gas pressure control valve 24 provided in the exhaust gas discharge pipe 27 is fully opened, the gas turbine 20 is started, and the rotation speed is sequentially increased.
When the rated speed is reached, steady operation is continued at that speed. Note that it is recommended that the gas turbine 20 cannot be started unless the exhaust gas flow rate control valve 43 and the emergency cutoff valve 44 have an opening of 0 and the pressure control valve 24 is not fully open. .

(C) Connection between gas turbine and heating furnace After confirming that the remote opening / closing valve 242 of the exhaust gas supply pipe 25 is fully opened, the exhaust gas cutoff valve 44 of the exhaust gas distribution pipe 26 of the planned connection furnace
Is fully opened, and the exhaust gas flow rate control valve 42 is operated to gradually open the exhaust gas flow rate control valve 43. As a result, when the pressure of the exhaust gas supply pipe 25 decreases, the opening degree of the exhaust gas pressure control valve 243 provided in the exhaust gas discharge pipe 27 leading to the chimney 23 decreases. When the number of heating furnaces 1 connected to the gas turbine 20 exceeds a certain number, the exhaust gas pressure control valve 243 is fully closed.

During this period, a signal from the air flow rate calculation control device 31 reduces the opening of the air flow rate control valve 33 provided in the suction pipe 61 of the blower 6, and the air flow rate to the heating furnace 1 is
The optimum value calculated from the information sent from each of the air flow rate instruction controller 32, the exhaust gas oxygen concentration meter 28, and the fuel flow rate instruction controller 531 is controlled.

(D) Separation of gas turbine from heating furnace Coke is generated and accumulated on the inner wall of the heated tube 12 by a side reaction, and the production efficiency of the heating furnace 1 decreases with the passage of time. Operation is interrupted at regular intervals,
Coke removal operation is required. Therefore, the heating furnace 1 is separated from the gas turbine 20. In addition to this regular maintenance work, the exhaust gas supply may be interrupted due to various troubles, production adjustments, shutdown of the entire furnace, etc.

When performing the disconnection, the exhaust gas flow rate adjusting controller 42 provided in the exhaust gas distribution pipe 26 of the heating furnace 1 is operated, and the exhaust gas flow rate adjusting valve 43 is gradually closed. At this time, in response to a signal from the air flow rate calculation control device 31, the air flow rate control valve 33 provided in the suction pipe 61 of the blower 6 sequentially increases its opening degree, and the air flow rate to the heating furnace 1 is controlled by the exhaust gas flow rate controller 42. , The oxygen concentration meter 28, the fuel flow rate controller 531 and other signals are adjusted to the optimum values.

At this time, if another heating furnace is connected to the gas turbine 20 in parallel at the same time, the exhaust gas supply pipe 2
The pressure fluctuation of No. 5 is small, and the pressure control valve 243 of the exhaust gas discharge pipe 27 hardly moves (in the normal operation, it is normally kept in the fully closed state). After the exhaust gas flow control valve 43 is fully opened,
The disconnection is completed by fully closing the exhaust gas cutoff valve 44.

After that, the heating furnace 1 is subjected to necessary maintenance such as coke removing operation, and after the starting operation by the method (a), is connected to the gas turbine 20 again by the method (c).

(E) Normal stop of heating furnace The heating furnace 1 is separated from the gas turbine 20 by the above-mentioned method (d), and thereafter, stop operations such as supply of raw materials and fuel and cooling of the heating furnace 1 are performed.

(F) Normal stop of gas turbine All the heating furnaces 1 are sequentially disconnected from the gas turbine 20 by the method of (d) above. In this process, the pressure of the exhaust gas supply pipe 25 gradually increases, so that the exhaust gas discharge pipe 2 leading to the chimney 23
The exhaust gas pressure control valve 243 of No. 7 starts to open sequentially, and the chimney 23
The emission of exhaust gas from the plant has started and is gradually increasing. After confirming that all the heating furnaces 1 have been disconnected and that the exhaust gas flow rate control valve 43 and the exhaust gas cutoff valve 44 of each exhaust gas distribution pipe 26 are all fully closed, a normal stop operation is performed according to the regulations, The turbine 20 is stopped.

(G) Control operation at the time of emergency stop of gas turbine When the gas turbine 20 is stopped due to a failure, the supply amount of exhaust gas decreases extremely rapidly. FIG. 3 shows the change over time in the exhaust gas supply amount (exhaust gas flow rate flowing in the exhaust gas supply pipe 25) after the gas turbine for an aircraft (output 25000 KW) used on the implementation side was stopped. From this figure, it is known that the exhaust gas supply amount decreases to 40% or less within 1 second after the stop, and becomes 20% or less after 2 seconds.

In response to such a rapid change in heat supply,
It is impossible to perform accurate and quick compensation control for each heating furnace without causing any interference or disturbance to the combustion amount of a large number of heating furnaces operating in parallel.

When the gas turbine 20 is urgently stopped, the trip detection controller 22 issues the following emergency treatment command signals (1) to (3). Command 1-1 Full open command signal of the air flow control valve 33 (about 2 until full open)
Seconds). Command 1-2 Calculation control start command signal to the air flow rate calculation control device 31. Command 2-1 Transmitted 1.5 seconds after the gas turbine stopped. A full closing command signal for the exhaust gas cutoff valve 44 provided in the exhaust gas distribution pipe 26 to the heating furnace 1 connected to the gas turbine 20 (about 3 seconds until fully opened). Command 2-2 Calculation control start command signal to the exhaust gas flow rate calculation control device 41. Command 3 Calculation control start command signal to the temperature setting control device 51.

The following arithmetic control is performed by these command signals. The product temperature control device 5 sets the set temperature of the temperature controller 52 provided in the outlet pipe of the heated pipe 12 of the heating furnace 1 connected to the gas turbine 20 according to a program prepared in advance, to the gas turbine 20. The value immediately before the stop was temporarily shifted to the high temperature side, and after a certain period of time, the original value was restored.

In the above embodiments, the change of the set temperature is shown as an example of a rectangular wave shape in which the temperature rises from the temperature before the change at a constant crest value and sharply falls after a lapse of a predetermined time. However, this is not limited to this type, and for example, since the set temperature at all times is constant, the set temperature may be increased to a desired set temperature.
When restoring the set value to a permissible value, it is possible not to make it stepwise, but to make it stepwise, linearly or exponentially lowered, and it is also possible to make its rise also triangular. .

The amount of shift of the set temperature to the high temperature side, the changing time and functional form, and the time integral value of the changing amount are the purpose of use of the heating furnace, the thermal characteristics, the gas turbine, and the like. Can be calculated in advance from the ratio of the amount of heat supplied to the heating furnace from the amount of heat supplied by fuel combustion, the characteristics of the control device used, the behavior when the gas turbine is stopped, and the like.

When the temperature set value is shifted to the high temperature side, the fuel flow rate controller 531 increases the opening degree of the fuel flow rate control valve 532 and increases the fuel supply amount by a fixed amount. Therefore, at this time, the indication value of the fuel flow rate controller 531 increases,
The signal is transmitted to the air flow rate calculation control device 31 of the air supply flow rate control device 3 for the heating furnace.

In such a case, the set value of the air flow rate controller 32 of the air supply amount control device 3 changes to the required air amount corresponding to the signal from the fuel flow controller 531. The opening degree of 33 is adjusted, and the supply amount of air is optimally controlled so that the combustion state in the heating furnace 1 is stably maintained.

The exhaust gas flow rate control device 4 of the gas turbine is
In accordance with the command signal, the setting of the exhaust gas flow rate controller 42 is changed to the flow rate "zero", and the output of this setting causes the exhaust gas flow rate control valve 43 to be fully closed.

As described above, according to the present invention, when the gas turbine is stopped unintentionally, the set temperature of the product temperature control device at the outlet of the pipe to be heated is increased, whereby the fuel and air supplied to the heating furnace are supplied. To increase the supply of.

It is possible to control the set value of the fuel supply amount to be supplied to the heating furnace to be higher than the value immediately before the stop of the gas turbine for a certain period of time without raising the set temperature of the product temperature control device. is there. Then, it is theoretically possible to set the increase amount to be substantially equal to the fuel increase amount to be increased by the control according to the present invention. However, such a control method cannot achieve the stable and high level control that can be realized by the present invention.

As an example of the change in the operating state of the heating furnace before and after the gas turbine is stopped, FIG. 3 shows the product temperature at the outlet of the heated pipe 12 (the value indicated by the temperature indicating controller 52) and the fuel supply amount (fuel flow rate). A change in the opening of the fuel flow rate control valve 532 is shown. From this graph, it is clear that according to the present invention, the temperature change of the decomposition product is kept within ± 2 ° C with respect to the temperature during normal operation.
Further, since the period in which such fluctuations occur is only about a few seconds, the quality of the product is not significantly affected.

[0057]

As described above, according to the apparatus and method of the present invention, an aircraft in which the exhaust gas is interrupted in an extremely short time at the time of an untimely stoppage in a heating apparatus having a gas turbine incorporated in a heating furnace. Even if a gas turbine for use is used, the amount of raw material supplied to the heating furnace is not changed when the gas turbine is stopped.
Moreover, the outlet temperature of the heated tube built into the heating furnace can be kept substantially constant, so that the operation of the heating furnace can be stably maintained, and therefore the safety of the entire plant including downstream processes can be secured. .

According to the present invention, it is possible to incorporate an aircraft gas turbine with high thermal efficiency into a heating furnace of a device for producing ethylene, hydrogen, etc. or a device with large energy consumption such as a large boiler. It has a remarkable effect on the improvement of total energy efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a heating device that can be used as, for example, a naphtha decomposition furnace for ethylene production.

FIG. 2 is a graph showing the shutdown characteristics of a gas turbine for an aircraft engine.

FIG. 3 is a product temperature at an outlet of a heated pipe, a fuel supply amount,
It is a graph which shows the change of the opening of a fuel flow control valve.

[Explanation of symbols]

 1 ... Heating furnace 10 ... Furnace body 11 ... Fuel combustion device 12 ... Heated tube 2 ... Gas turbine exhaust gas supply device 20 ... ... Gas turbine for aircraft engine 21 ... Generator 22 ... Trip detector 23 ... Chimney 24 ... Exhaust gas pressure control device 25 ... Exhaust gas supply pipe 26 Exhaust gas distribution pipe 27 Exhaust gas discharge pipe 28 Exhaust gas oxygen meter 3 Air supply amount control device 31 ··· Air flow rate calculation control device 32 ··· Air flow rate indicating controller 33 ··· Air flow rate control valve 4 ··· Exhaust gas supply amount control device 41 ··· Exhaust gas Flow rate control device 42 ... Exhaust gas flow rate indicator 43 ... Exhaust gas flow rate control valve 44 ... Exhaust gas shutoff valve 5 ... Product temperature control device 51 ... Temperature calculation control device 52 ... Temperature indicating controller 53 ... Fuel Supply amount control device 531 ... Fuel flow rate indicator controller 532 ... Fuel flow rate control valve 54 ... Fuel shutoff valve 6 ... Blower 7 ... Fuel supply device 8 .... Material supply device

Claims (7)

[Claims] 1. A heating furnace (1) comprising a fuel combustion device (11) and a heated pipe (12) through which a fluid to be heated flows.
And a device (2) for introducing high-temperature exhaust gas of a gas turbine (20) provided outside the heating furnace into the heating furnace (1) and a fuel combustion device (11) for the heating furnace (1). A device (7), a blower (6) for supplying air into the heating furnace (1), and a device for controlling the air supply amount to the heating furnace (1) according to the fuel supply amount to the heating furnace (1). (3), a device (4) for controlling the exhaust gas supply amount of the gas turbine (20) to the heating furnace (1), and a device (53) for controlling the fuel supply amount to the heating furnace (1), A device (5) for controlling the fuel supply amount to control the temperature of the product flowing out of the heated pipe (12), and the combustion heat generated in the heating furnace (1) and the gas turbine (20). ) Is used together with the heat of the high-temperature exhaust gas to heat the fluid flowing through the heated pipe (12), the gas turbine ( 20) is a gas turbine for an aircraft engine, and the exhaust gas supply amount control device (4) has an exhaust gas cutoff valve (44) for closing the exhaust gas distribution pipe (26) to the heating furnace (1) when the gas turbine is stopped. The product temperature control device (5) is provided with means for setting the temperature set value higher than the value before the stop for a certain time when the gas turbine is stopped, and the air supply amount control device (3) controls the product temperature Corresponding to the fuel supply amount indicated by the fuel indicating controller (531) of the control device (5). The heating device described above, characterized in that the flow rate of air supplied to the heating furnace (1) is controlled. 2. A gas turbine for an aircraft engine (2)
0) generates high temperature exhaust gas of 400 to 700 ° C., and the time until the flow rate of the high temperature exhaust gas is reduced from the normal flow rate to half when the high temperature exhaust gas is stopped is 0.5 seconds or more and 20 seconds or less. Heating device. 3. An air flow rate control device (3), wherein an air flow rate indicating controller (3) provided in an air supply pipe (61, 62).
2) and an air flow rate control valve (33), and an air flow rate operation control device (31) for adjusting the opening degree of the air flow rate control valve (33) in response to the output of the flow rate indicating controller (32). Item 3. A heating device according to item 1 or 2. 4. An exhaust gas flow rate controller (4) provided in an exhaust gas distribution pipe (26), wherein the exhaust gas supply amount control device (4) is provided.
2) and the exhaust gas flow rate control valve (43) and the exhaust gas flow rate calculation control device (4) for adjusting the opening degree of the exhaust gas flow rate control valve (43) in response to the output of the exhaust gas flow rate control valve (42).
The heating device according to any one of claims 1 to 3, further comprising 1). 5. A product temperature control device (5), a temperature indicating controller (52) provided in a product transport pipe (91) connected to an outlet of a heated pipe (12), and a heating furnace (1). Fuel supply amount adjusting device (53) provided in the fuel supply pipe (71) for controlling the fuel supply amount, and a temperature calculation for controlling the operation of the fuel supply amount adjusting device (53) in response to the output of the temperature indicating controller (52). Heating device according to any one of claims 1 to 4, comprising a control device (51). 6. A heating furnace (1) equipped with a fuel combustion device (11) and a heated pipe (12) through which a fluid to be heated flows, and a gas turbine (1) provided outside the heating furnace (1). 20), a device for introducing high-temperature exhaust gas of the gas turbine (20) into the heating furnace (1), a device (7) for supplying fuel to the heating furnace (1), and air in the heating furnace (1). A blower (6) for supplying air and a device (3) for controlling the air supply amount to the heating furnace (1) according to the fuel supply amount to the heating furnace (1)
And a device (4) for controlling the exhaust gas supply amount of the gas turbine (20) to the heating furnace (1) and a device (53) for controlling the fuel supply amount to the heating furnace (1). In a heating device comprising a device (5) for controlling the amount and controlling the temperature of the product flowing out of the heated pipe (12), the production state of the product when the gas turbine (20) is stopped suddenly. A method for controlling the above heating device for maintaining a constant value, wherein a trip detection controller (22) comprises a gas turbine (2
Step 0) detecting the stop and transmitting a trip detection signal. Closing the line (26) for distributing the exhaust gas from the gas turbine (20) to the heating furnace (1). Pipe lines (61, 6) for supplying air into the heating furnace (1)
The step of fully opening the air flow control valve (33) provided in 2). Changing the set temperature of the product temperature control device (5) to a higher temperature side than the value immediately before the gas turbine (20) is stopped. With the product temperature control device (5), the opening of the fuel flow rate control valve (532) is increased in order to increase the fuel supply amount to the heating furnace (1) corresponding to the set temperature increased by the steps described in the preceding paragraph. Controlling steps. In order to maintain the air supply amount necessary for combustion of the fuel corresponding to the fuel supply amount instructed by the fuel flow rate instruction controller (531), a control operation is performed to the air supply amount control device (3) to the heating furnace (1). Steps to take. A step of returning the set temperature of the product temperature control device (5) to the original set value after a predetermined time has elapsed. A step of controlling the fuel supply amount to the heating furnace (1) by the product temperature control device (5) corresponding to the set temperature returned to the normal value in the step described in the preceding paragraph. Also, in order to maintain the air flow rate necessary for the combustion of the fuel corresponding to the fuel supply amount indicated by the fuel flow rate instruction controller (531), the air supply amount control device (3) for the heating furnace (1) is normally operated. A step for performing a control action. And a method of controlling the heating device. 7. The change of the set temperature of the product temperature control device (5) is changed to a rectangular wave shape by a predetermined fixed value, which is higher than the value immediately before the gas turbine (20) is stopped for a fixed time. 7. The method for controlling the heating device according to 6.