KR102590658B1 - System and control method thereof for natural gas dual fuel power plant - Google Patents

Abstract

The present invention has the advantage of safely managing gas by using a nitrogen generator to inject nitrogen into the space between the inner and outer pipes of the double pipe in a natural gas co-fired power generation system using natural gas, an explosive fuel. Additionally, the use of nitrogen, an inert gas, has the advantage of safely managing the co-fired power generation system as ignition or explosion does not occur in the pipe even if gas leaks, and condensate, lubricant, and dust are stored in the space between the inner and outer pipes of the double pipe. It has the advantage of reducing piping management problems and efficient piping management by preventing the inflow of various foreign substances, as well as gas safety and piping management, as well as engine start and maintenance by using air with high oxygen concentration separated from the nitrogen generator. It has the advantage of enabling smooth ignition and operation during low-load operation, and reducing the occurrence of incomplete combustion by adding it to the intake air when changing the operation mode to co-firing operation.

Description

Natural gas co-fired power generation system and control method {SYSTEM AND CONTROL METHOD THEREOF FOR NATURAL GAS DUAL FUEL POWER PLANT}

The present invention relates to a natural gas co-fired power generation system and control method.

In natural gas co-fired power generation systems such as ships and land-based co-fired engines where gas safety management is important because natural gas is used as fuel, the area handling natural gas is divided into a safety area in accordance with relevant international regulations and laws. To prevent the risk of natural gas leakage, double wall pipes are generally used.

Accordingly, the double pipe used has a concentric structure in which the inner pipe and the outer pipe have different diameters, and natural gas is supplied and transported through the inner pipe, and the space between the inner pipe and the outer pipe is Air flows in the opposite direction of the gas supply direction, and the air pressure flowing at this time is lower than atmospheric pressure. Due to this structure and operation, even if the natural gas supplied through the inner pipe of the double pipe leaks, the air flowing between the inner and outer pipes It is discharged to the outside together with gas, thereby preventing gas leakage.

A fan is used to allow air to flow in the space between the inner and outer pipes of the double pipe used for gas supply in this co-fired power generation system, and the inlet through which the air flows at this time is located in the engine room.

Accordingly, condensation may be generated in the engine room air due to external influences, and various foreign substances such as lubricant and dust may enter and cause problems such as corrosion in the pipes.

In particular, in a co-fired power generation system that uses fuel such as kerosene with a low flash point, when the temperature in the engine room is high, such as in the summer, kerosene in vapor form in the air enters the space between the inner and outer pipes of the double pipe along with the air, and then lowers the temperature. It may explode due to its flash point, creating a safety issue.

In addition, due to the characteristics of the co-fired power generation system, optimal combustion does not occur when the engine is started and the operation is switched to gas co-firing, resulting in the generation of CO and NOx.

Republic of Korea Patent Publication No. 10-0902958 (2009.06.08.)

The purpose of the present invention is to solve existing problems in consideration of various existing problems. When switching operation modes between diesel combustion and gas co-firing of a co-fired power generation system, the nitrogen generator installed for purging the system is used to purge the generated nitrogen into a double pipe. The aim is to provide a natural gas co-fired power generation system and control method that can effectively manage gas safety, such as preventing gas explosion by injecting it into the space between the inner and outer pipes and allowing it to flow.

In addition, another object of the present invention is to efficiently manage pipes by preventing the inflow of various foreign substances such as condensate, lubricant, and dust into the space between the inner and outer pipes, and to prevent the problem of kerosene with a low flash point entering with air and exploding. The purpose is to provide a natural gas co-fired power generation system and control method that can prevent.

In addition, another object of the present invention is to store air with a high oxygen concentration that is separated from the nitrogen generator and discarded to the outside in a separate tank to utilize the high oxygen concentration during engine start and low load operation to facilitate ignition and operation. The aim is to provide a natural gas co-firing power generation system and control method that can reduce the occurrence of incomplete combustion by introducing it into the intake air when switching from diesel operation to co-firing operation.

The natural gas co-firing power generation system according to an embodiment of the present invention to solve the above technical problem includes a double pipe installed between the co-firing engine and the LNG base, which consists of an inner pipe supplied with natural gas and an outer pipe supplied with nitrogen; GVU (Gas Valve Unit) installed on one side of the double pipe; A natural gas pressure sensor installed on one side of the inner pipe to measure the pressure of natural gas supplied to the co-fired engine; A nitrogen gas pressure sensor installed on one side of the double pipe to measure the pressure of nitrogen flowing between the inner pipe and the outer pipe; A natural gas temperature sensor installed on one side of the inner pipe to measure natural gas temperature; A nitrogen generator installed on one side of the double pipe to supply nitrogen to the space between the inner pipe and the outer pipe; A nitrogen tank installed between the double pipe and the nitrogen generator; An oxygen tank installed between the nitrogen generator and the co-firing engine; An oxygen supply valve installed between the oxygen tank and the co-firing engine; A gas leak detection sensor connected to one side of the double pipe via the GVU to detect natural gas components in nitrogen; An integrated controller connected to the co-firing engine, GVU, nitrogen gas pressure sensor, nitrogen generator, nitrogen tank, oxygen tank, and gas leak detection sensor to control the co-firing power generation system; a nitrogen supply valve installed between the outer pipe and the nitrogen tank to supply nitrogen to the space between the inner pipe and the outer pipe; a gas injection valve installed between the co-firing engine and the double pipe to control injection of natural gas into the co-firing engine; and a gas operation monitoring device that is connected to the integrated controller and monitors the operation of the co-fired power generation system.

In another embodiment, the GVU of the present invention receives a signal from the integrated controller, supplies gas to the co-fired engine, and includes a gas supply valve installed between the LNG base and the double pipe to block the gas supply in an emergency. It is characterized by

As another embodiment, the GVU of the present invention includes a gas purging valve installed on one side of the inner pipe to receive a signal from the integrated controller and close during gas supply or co-firing operation, and open when gas leaks to discharge natural gas to the outside. It is characterized by:

As another embodiment, the GVU of the present invention includes an emergency nitrogen supply valve installed on one side of the outer piping to receive a signal from the integrated controller and close during gas supply and co-firing operation, and open when gas leaks to supply nitrogen for purging. It is characterized by:

As another embodiment, the GVU of the present invention includes a nitrogen purging valve installed on one side of the outer pipe to receive a signal from the integrated controller and discharge nitrogen flowing between the inner pipe and the outer pipe to the outside of the co-firing engine room. It is characterized by

As another embodiment, the nitrogen generator of the present invention is characterized by supplying nitrogen to the space between the inner pipe and the outer pipe and for purging, or to the intake system of the mixed combustion engine.

In another embodiment, an oxygen compressor that operates by receiving a signal from the integrated controller is installed between the nitrogen generator of the present invention and the oxygen tank.

As another embodiment, the oxygen supply valve of the present invention is characterized by receiving a signal from the integrated controller for oxygen generated and stored in the nitrogen generator and controlling the input of oxygen in the oxygen tank into the co-fired engine.

As another embodiment, the nitrogen supply valve of the present invention receives a signal from the integrated controller to supply nitrogen generated and stored in the nitrogen generator between the inner pipe and the outer pipe, or supplies nitrogen for purging in the event of a gas leak. do.

As another embodiment, the gas operation monitoring device of the present invention receives signals from the nitrogen gas pressure sensor, gas leak detection sensor, and integrated controller to check whether gas supply occurs normally and to generate an alarm when gas leaks, thereby supplying gas in a co-fired power generation system. It is characterized by switching from diesel operation to mixed combustion operation while checking the leak status in real time.

Meanwhile, the natural gas co-firing power generation system control method according to an embodiment of the present invention includes an engine starting step of providing a start signal to the co-firing engine through an integrated controller when the signal received from each facility of the co-firing power generation system is normal; A system purging step of purging the natural gas remaining in the co-firing engine or the inner pipe of the double pipe connecting the co-firing engine and the LNG base under the control of the integrated controller before starting the co-firing engine; A diesel operation step in which the co-fired engine proceeds to diesel operation after completing the system purging step; An oxygen supply step of supplying oxygen simultaneously with starting the diesel operation step; In the diesel operation stage, the co-firing engine is raised to a load that can be switched to an operation mode, and when the signals received from each device of the co-firing power generation system are normal, the operation mode is manually switched by the driver's selection and the co-firing operation proceeds to co-firing operation. step; A nitrogen supply step of supplying nitrogen from a nitrogen generator between the inner piping and the outer piping of the double pipe when natural gas is supplied to the co-firing engine through the inner piping of the double pipe under the control of the integrated controller as the co-firing operation step progresses. ; A gas leak detection step of detecting a gas leak under the control of the integrated controller after performing the co-firing operation step; The nitrogen supply step During the process, if the amount of nitrogen in the nitrogen tank falls below a certain level, a nitrogen generator operation step of stopping operation of the nitrogen generator under the control of the integrated controller.

As another embodiment, the diesel operation stage of the present invention is characterized in that it is operated until switching to co-fueling operation through a gas operation monitoring device.

As another embodiment, the oxygen supply in the oxygen supply step of the present invention is characterized by supplying the load up to a load that can switch the operation mode after starting the co-fired engine.

As another embodiment, the gas leak detection step of the present invention is characterized in that gas leak is detected by a gas leak detection sensor when nitrogen flowing between the inner pipe and the outer pipe of the double pipe is discharged to the outside through the outlet of the outer pipe. Do it as

As another embodiment, the gas leak detection step of the present invention measures the pressure of nitrogen flowing between the inner pipe 31 and the outer pipe of the double pipe by the nitrogen gas pressure sensor of the GVU installed in the double pipe to determine the pressure due to natural gas leak. It is characterized by detecting fluctuations or detecting gas leaks.

The present invention has the advantage of safely managing gas by using a nitrogen generator to inject nitrogen into the space between the inner and outer pipes of the double pipe in a natural gas co-fired power generation system using natural gas, an explosive fuel. There is.

In addition, the use of nitrogen, an inert gas, has the advantage of safely managing the co-fired power generation system because ignition or explosion does not occur in the pipes even if gas leaks.

In addition, it has the advantage of reducing pipe management problems and enabling efficient pipe management by preventing the inflow of various foreign substances such as condensate, lubricant, and dust into the space between the inner and outer pipes of the double pipe.

In addition, in addition to gas safety and piping management, by using air with a high oxygen concentration separated from the nitrogen generator, ignition and operation can be smoothed during engine start and low load operation, and suction can be used when switching to operation mode for mixed combustion operation. It has the advantage of reducing the occurrence of incomplete combustion by injecting it into the air.

1 is a block diagram of a natural gas co-fired power generation system according to a first embodiment of the present invention;
Figures 2 and 3 are cross-sectional views of the front and side of the double pipe applied to Figure 1,
Figure 4 is a configuration diagram of a natural gas co-fired power generation system according to a second embodiment of the present invention;
Figure 5 is a control flow chart of the natural gas co-fired power generation system according to the present invention;

In order to fully understand the present invention, a preferred embodiment of the present invention will be described with reference to the accompanying drawings FIGS. 1 to 5. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. Therefore, the shapes of elements in the drawings may be exaggerated to emphasize a clearer description. It should be noted that the same configuration may be indicated by the same reference numeral in each drawing. Detailed descriptions of well-known functions and configurations that are judged to unnecessarily obscure the gist of the present invention are omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the natural gas co-firing power generation system according to the first embodiment of the present invention consists of an inner pipe 31 to which natural gas is supplied and an outer pipe 32 to which nitrogen is supplied, and is used to power the co-firing engine 1 and LNG. A double pipe (3) installed between the bases (2); A GVU (Gas Valve Unit) (4) installed on one side of the double pipe (3) to control the supply of natural gas to the co-fired engine (1), block the gas supply in case of leakage, and control gas discharge to the outside; A natural gas pressure sensor (5) installed on one side of the inner pipe (31) to measure the pressure of natural gas supplied to the co-fired engine (1); A nitrogen gas pressure sensor (51) installed on one side of the double pipe (3) to measure the pressure of nitrogen flowing between the inner pipe (31) and the outer pipe (32); A natural gas temperature sensor (6) installed on one side of the inner pipe (31) to measure the natural gas temperature; A nitrogen generator (7) installed on one side of the double pipe (3) to supply nitrogen to the space between the inner pipe (31) and the outer pipe (32); A nitrogen tank (70) installed between the double pipe (3) and the nitrogen generator (7); An oxygen tank (71) installed between the nitrogen generator (7) and the co-firing engine (1); An oxygen supply valve (72) installed between the oxygen tank (71) and the co-firing engine (1); A gas leak detection sensor (8) connected to one side of the double pipe (3) via the GVU (4) to detect natural gas components in nitrogen; It is connected to the co-firing engine (1), GVU (4), nitrogen gas pressure sensor (51), nitrogen generator (7), nitrogen tank (70), oxygen tank (71), and gas leak detection sensor (8) to generate co-firing power. Integrated controller (9) that controls the system; A nitrogen supply valve (10) installed between the outer pipe (32) and the nitrogen tank (70) to supply nitrogen to the space between the inner pipe (31) and the outer pipe (32); A gas injection valve (100) installed between the co-firing engine (1) and the double pipe (3) to control injection of natural gas into the co-firing engine (1); It is configured to include a gas operation monitoring device (11) that is connected to the integrated controller (9) and monitors the operation of the co-fired power generation system.

At this time, the co-firing engine 1 serves to generate power using liquid fuel (diesel, etc.) and natural gas as fuel.

The LNG base 2 serves to supply natural gas, which is a fuel for power generation.

The double pipe 3 is configured so that the inner pipe 31 and the outer pipe 32 of different diameters form a concentric structure, as shown in Figures 2 and 3, and gas flows from the inner pipe 31 to which natural gas is supplied. Even if it leaks, it serves to prevent natural gas from leaking to the outside through the outer pipe 32 through which nitrogen is supplied.

The GVU (4) is controlled by receiving a signal from the integrated controller (9), and is installed between the LNG base (2) and the double pipe (3) to supply gas to the co-firing engine (1) and to supply gas in an emergency. A gas supply valve (41) that blocks; A gas purging valve (42) installed on one side of the inner pipe (31), which is closed during gas supply and co-firing operation and opens when gas is leaked to discharge natural gas to the outside; An emergency nitrogen supply valve (43) installed on one side of the outer pipe (32), which is closed during gas supply and co-firing operation and opens when gas leaks to supply nitrogen for purging; It is configured to include a nitrogen purging valve (44) installed on one side of the outer pipe (32) to discharge nitrogen flowing between the inner pipe (31) and the outer pipe (32) to the outside of the room of the co-fired engine (1). .

The nitrogen gas pressure sensor 51 measures the pressure of nitrogen flowing between the inner pipe 31 and the outer pipe 32 of the double pipe 3, detects pressure fluctuations due to natural gas leakage, and determines gas leakage. Do it.

The natural gas temperature sensor 6 serves to measure the temperature of natural gas supplied to the co-fired engine 1 through the inner pipe 31 of the double pipe 3.

The nitrogen generator (7) supplies nitrogen to the space between the inner pipe (31) and the outer pipe (32) of the double pipe (3) and for purging, or supplies nitrogen to the intake system of the co-fired engine (1) for optimal combustion. It serves to separate nitrogen and oxygen through pressure swing absorption (PSA) by sucking and compressing external air.

The nitrogen tank 70 serves to store nitrogen separated from the nitrogen generator 7.

The oxygen tank 71 serves to separate nitrogen from the nitrogen generator 7 and store air with a high oxygen concentration remaining.

The oxygen supply valve 72 receives the oxygen generated and stored in the nitrogen generator 7 from the integrated controller 9 and supplies oxygen in the oxygen tank 71 for optimized combustion of the co-fired engine 1. It plays a role in controlling what is input into the co-firing engine (1).

The gas leak detection sensor (8) detects a gas leak in the room of the co-fired engine (1) or is installed at the end of the double pipe (3) to detect natural gas components in nitrogen discharged to the outside and detects the gas leak between the integrated controller (9) and the gas. It serves to send a gas leak signal to the operation monitoring device (11).

The integrated controller (9) controls each part of the co-firing power generation system, such as the co-firing engine (1), nitrogen generator (7), natural gas pressure sensor (5), natural gas temperature sensor (6), and gas leak detection sensor (8). Receive signals from the GVU (4) to control gas supply, blocking, and external discharge, and control the nitrogen generator (7) to supply nitrogen and oxygen and to supply nitrogen in the nitrogen tank (70) and oxygen tank (71). When there is a lack of oxygen, the nitrogen generator (7) is operated to reduce incomplete combustion of the co-fired engine (1) and control it to achieve optimized combustion.

The nitrogen supply valve 10 receives a signal from the integrated controller 9 to supply nitrogen generated and stored in the nitrogen generator 7 between the inner pipe 31 and the outer pipe 32 of the double pipe 3. And it serves to supply nitrogen for purging in case of gas leak.

The gas injection valve 100 receives a signal from the integrated controller 9 during co-firing operation and serves to control the injection of natural gas into the co-firing engine 1 according to the load.

The gas operation monitoring device 11 receives signals from the nitrogen gas pressure sensor 51, the gas leak detection sensor 8, and the integrated controller 9 to determine whether gas supply is normal and to generate an alarm when gas leaks. It plays a role in switching from diesel operation to co-fired operation by checking the gas supply and leakage status in the power generation system in real time.

By receiving signals from the gas leak detection sensor (8) and the integrated controller (9), such as whether the gas supply is normal and an alarm occurring in the event of a gas leak, the status related to gas supply and leakage in the natural gas co-fired power generation system can be checked in real time. It plays a role in switching the driving mode from driving to mixed driving.

Meanwhile, in the natural gas co-fired power generation system according to the second embodiment of the present invention, as shown in FIG. 4, an oxygen compressor 73 is installed between the nitrogen generator 7 and the oxygen tank 71, and the oxygen Before storing the air with a high oxygen concentration separated through the nitrogen generator 7 in the oxygen tank 71, the compressor 73 also produces oxygen for starting air of the co-fired engine 1, which requires high pressure. It has a usable role.

At this time, the oxygen compressor 73 operates by receiving a signal from the integrated controller 9, and the oxygen supply valve 72 installed between the oxygen tank 71 and the co-firing engine 1 provides not only oxygen supply but also pressure. It consists of a regulator that can also perform a regulating role and is used to optimize starting air and combustion of the co-fired engine (1).

Accordingly, by using air with a high oxygen concentration as starting air, ignition can be performed more efficiently and facility utilization can be improved.

Next, the control method of the natural gas co-fired power generation system of the present invention configured as described above includes an engine starting step (S100); System purging step (S200); Diesel operation stage (S300); Oxygen supply step (S400); Co-firing operation stage (S500); Nitrogen supply step (S600); Gas leak detection step (S700); It consists of a nitrogen generator operation step (S800).

That is, the engine start-up step (S100) is performed by giving a start signal to the co-fired engine (1) through the integrated controller (9) when the signal received from each facility of the co-fired power generation system is normal.

The system purging step (S200) is a double pipe connecting the co-firing engine (1) or the co-firing engine (1) and the LNG base (2) under the control of the integrated controller (9) before starting the co-firing engine (1). Proceed to purge the natural gas remaining in the inner pipe (31) of 3).

Then, nitrogen is supplied through the nitrogen supply valve 10 and the emergency nitrogen supply valve 43, and at the same time, the gas purging valve 42 is opened to discharge the gas to the outside of the power plant.

This operation operates equally during normal and emergency stops of the co-fired engine 1, thereby managing gas safety.

In the diesel operation step (S300), the co-firing engine 1 proceeds to diesel operation after completing the system purging step (S200), but is operated before switching to co-firing operation through the gas operation monitoring device 11.

The oxygen supply step (S400) supplies oxygen to improve incomplete combustion of the co-fired engine (1) that appears at low load after starting in the diesel operation step (S300).

In the oxygen supply step (S400), the integrated controller 9 controls the oxygen supply valve 72 to supply oxygen in the oxygen tank 71 to the intake system of the co-fired engine (1). At this time, oxygen supply is After starting the co-firing engine (1), the operating mode is supplied to a load capable of being switched. Typically, the operating mode can be switched at a load of 10 to 30%, and is set differently depending on the capacity and model of the co-firing engine (1).

In addition, oxygen supply is stopped when the optimal air-fuel ratio set through pre-testing is reached or the oxygen in the oxygen tank 71 falls below a certain amount, and oxygen is charged through the nitrogen generator operation step (S800).

In the diesel operation step (S300), the co-firing engine (1) is raised to a load that can be switched to an operation mode, and when the signals received from each device of the co-firing power generation system are normal, the gas operation monitoring device (11) displays the co-firing engine ( 1) Whether the driving mode can be switched is displayed. At this time, the driving mode is switched manually by the driver's selection, and when the driving mode is switched through the gas operation monitoring device 11, the mixed combustion operation step (S500) is performed. .

And, the integrated controller 9 controls the gas supply valve 41 and the gas injection valve 100 to supply natural gas to the co-fired engine 1 through the inner pipe 31 of the double pipe 3. The pressure and temperature of the natural gas supplied at this time vary depending on the type, capacity, and engine load of the co-firing engine (1).

In addition, at the same time as gas is supplied to the engine, The nitrogen supply step (S600) proceeds, and the integrated controller (9) controls the nitrogen supply valve (10) and the nitrogen purging valve (44) to transfer the nitrogen stored in the nitrogen tank (70) into the double pipe (3). It is continuously supplied between the inner pipe (31) and the outer pipe (32) and discharged outside the co-fired engine (1) room to prevent fire and explosion due to gas leakage.

At this time, the supplied nitrogen flow rate varies depending on the length of the double pipe (3), the size of the space between the inner and outer sides, the nitrogen supply pressure, etc., and is controlled by the operation of the nitrogen supply valve (10).

In addition, the nitrogen pressure generated by the nitrogen generator (7) and stored in the nitrogen tank (70) is lower than the pressure of the natural gas flowing in the inner pipe (31) of the double pipe (3) and higher than atmospheric pressure.

Accordingly, even if gas leaks from the inner pipe 31 of the double pipe 3, nitrogen flows between the inner pipe 31 and the outer pipe 32 of the double pipe 3, preventing fire and explosion from occurring and the co-fired engine (1). ) is discharged outside the room.

And the nitrogen supply step (S600) During the process, when the amount of nitrogen in the nitrogen tank 70 falls below a certain level, the integrated controller 9 proceeds with the nitrogen generator operation step (S800) to separate nitrogen in the air and store it in the nitrogen tank 70. The amount of nitrogen in the nitrogen tank (70) is maintained, and the capacity of the nitrogen tank (70) varies depending on the type, capacity, and control characteristics of the co-firing engine (1), and the co-firing engine (1) and gas piping before and after starting the co-firing engine (1). It is calculated to be larger than the capacity that can be purged at once.

Additionally, when switching operation modes, the integrated controller 9 controls not only the nitrogen supply step (S600) but also the oxygen supply step (S400).

At this time, when the operation is switched from the diesel mode to the co-firing mode, due to the nature of the co-firing operation, natural gas fuel is injected into the intake system, so the air required for combustion is reduced, and combustion of the co-firing engine 1 occurs incompletely. In order to improve this, the integrated controller 9 controls the oxygen supply valve 72 to supply oxygen in the oxygen tank 71 to the co-fired engine 1, thereby compensating for temporary incomplete combustion and changes in air-fuel ratio due to operation change. It can increase combustion efficiency and reduce air pollutants in exhaust gases.

At this time, the supplied oxygen is supplied until the optimal air-fuel ratio set through pre-testing is reached after the operation mode conversion is completed.

In addition, when the oxygen in the oxygen tank 71 falls below a certain amount or when knocking occurs in the co-fired engine 1, supply is stopped, and oxygen is charged through the nitrogen generator operation step (S800).

In addition, the capacity of the oxygen tank 71 varies depending on the type, capacity, and control characteristics of the co-firing engine 1, and the amount supplied during start-up and low load is larger than the amount supplied when switching operation modes. The capacity of the oxygen tank 71 is calculated based on the amount.

In addition, after the co-firing operation step (S500) is performed, a gas leak detection step (S700) is performed to manage and control the gas safety of the co-firing power generation system. At this time, gas leaks are detected in two ways.

First, leakage is detected through a gas leak detection sensor (8) installed at the nitrogen outlet flowing between the inner pipe (31) and the outer pipe (32) of the double pipe (3), and the gas pressure of the inner pipe (31) is Since the pressure of nitrogen flowing between the inner pipe 31 and the outer pipe 32 is higher than that, even if gas leaks, it is discharged to the outside along with nitrogen.

At this time, since the space between the inner pipe 31 and the outer pipe 32 of the double pipe 3 is filled with nitrogen, an inert gas, it does not ignite or explode in the double pipe 3 even if the gas leaks.

In particular, a structure such as a windbreak is installed around the nitrogen outlet to prevent the influence of the external environment, and the gas leak detection efficiency is increased by allowing the gas to remain within the structure until it is detected. The structure includes a windbreak, roof, etc. It is composed of and has different shapes depending on site conditions.

Second, gas leakage is detected through changes in pressure using the natural gas pressure sensor (5) and the nitrogen gas pressure sensor (51) installed in the double pipe (3) between the GVU (4) and the co-firing engine (1).

At this time, when gas leaks from the inner pipe 31 of the double pipe 3, the gas pressure supplied to the co-fired engine 1 becomes smaller than the natural gas pressure measured in the GVU 4, and the inner pipe 31 The nitrogen pressure between the and the outer pipe 32 increases by taking advantage of the phenomenon.

And the pressure change that can be considered a gas leak varies depending on the diameter and length of the double pipe (3), gas supply pressure, etc.

If a problem occurs not only in the inner pipe 31 but also in the outer pipe 32 and gas leaks, the leak is detected through a sensor installed in the room of the co-fired engine (1), and this sensor detects the gas. It is installed on the GVU (4), the top of the co-fired engine (1), etc., where there is a high possibility of leakage. In this case, the installation location and number of gas leak detectors (8) may vary depending on site conditions.

In this way, gas leaks can be detected in two ways, and when a gas leak is detected, related warnings and alarms are also generated in the gas operation monitoring device 11, so that the driver can immediately recognize the related situation.

When a gas leak is detected using the above principle, the integrated controller 9 manages safety by controlling the co-fired power generation system in the following order.

First, when a gas leak is detected, the gas injection valve 100 and the gas supply valve 41 in the GVU 4 are closed to stop the gas supply, and the gas purging valve 42 is opened to release the remaining gas in the gas pipe to the power plant. Discharge to the outside.

In addition, the emergency nitrogen supply valve 43 in the GVU (4) is opened, and the nitrogen generated through the nitrogen generator (7) and stored in the nitrogen tank (70) is supplied to the double pipe (3), thereby eliminating gas that may remain. is purged and discharged to the outside, and at the same time, the integrated controller (9) automatically and immediately switches from the co-fired operation mode to the diesel operation mode to ensure that there is no problem in power supply.

In addition, the operation mode can be switched from co-fuel operation to diesel mode through the gas operation monitoring device 11 according to the operator's judgment, and the operation mode can be switched by pressing the emergency operation mode switch button.

As such, the present invention uses a nitrogen generator (7) in a natural gas co-fired power generation system using natural gas, an explosive fuel, to create a space between the inner pipe (31) and the outer pipe (32) of the double pipe (3). There is an advantage in that the gas can be managed safely by injecting nitrogen into it and allowing it to flow.

In addition, the present invention has the advantage of safely managing the co-fired power generation system because, by using nitrogen, an inert gas, ignition or explosion does not occur in the pipe even if the gas leaks.

In addition, the present invention prevents the inflow of various foreign substances such as condensate, lubricant, and dust into the space between the inner pipe 31 and the outer pipe 32 of the double pipe (3), thereby reducing pipe management problems and enabling efficient pipe management. There is an advantage.

In addition, the present invention not only provides gas safety and piping management, but also uses air with a high oxygen concentration separated from the nitrogen generator (7) to facilitate ignition and operation during engine start and low load operation, and co-fueling operation. It has the advantage of reducing the occurrence of incomplete combustion by adding it to the intake air when changing the operation mode.

Meanwhile, the present invention is not limited to the above-described embodiments, but can be implemented with modifications and modifications without departing from the gist of the present invention, and the technical idea to which such modifications and modifications are applied also falls within the scope of the following patent claims. Must see.

1: Co-firing engine 2: LNG base
3: double pipe 31: inner pipe
32: External piping 4: GVU
41: gas supply valve 42: gas purging valve
43: Emergency nitrogen supply valve 44: Nitrogen purging valve
5: Natural gas pressure sensor 51: Nitrogen gas pressure sensor
6: Natural gas temperature sensor 7: Nitrogen generator
70: nitrogen tank 71: oxygen tank
72: Oxygen supply valve 73: Oxygen compressor
8: Gas leak detection sensor 9: Integrated controller
10: Nitrogen supply valve 11: Gas operation monitoring device
100: Gas injection valve

Claims (15)

A double pipe (3) installed between the co-fired engine (1) and the LNG base (2), consisting of an inner pipe (31) to which natural gas is supplied and an outer pipe (32) to which nitrogen is supplied; GVU (Gas Valve Unit) (4) installed on one side of the double pipe (3); A natural gas pressure sensor (5) installed on one side of the inner pipe (31) to measure the pressure of natural gas supplied to the co-fired engine (1); A nitrogen gas pressure sensor (51) installed on one side of the double pipe (3) to measure the pressure of nitrogen flowing between the inner pipe (31) and the outer pipe (32); A natural gas temperature sensor (6) installed on one side of the inner pipe (31) to measure the natural gas temperature; A nitrogen generator (7) installed on one side of the double pipe (3) to supply nitrogen to the space between the inner pipe (31) and the outer pipe (32); A nitrogen tank (70) installed between the double pipe (3) and the nitrogen generator (7); An oxygen tank (71) installed between the nitrogen generator (7) and the co-firing engine (1); An oxygen supply valve (72) installed between the oxygen tank (71) and the co-firing engine (1); A gas leak detection sensor (8) connected to one side of the double pipe (3) via the GVU (4) to detect natural gas components in nitrogen; It is connected to the co-firing engine (1), GVU (4), nitrogen gas pressure sensor (51), nitrogen generator (7), nitrogen tank (70), oxygen tank (71), and gas leak detection sensor (8) to generate co-firing power. Integrated controller (9) that controls the system; A nitrogen supply valve (10) installed between the outer pipe (32) and the nitrogen tank (70) to supply nitrogen to the space between the inner pipe (31) and the outer pipe (32); A gas injection valve (100) installed between the co-firing engine (1) and the double pipe (3) to control injection of natural gas into the co-firing engine (1); A natural gas co-fired power generation system comprising a gas operation monitoring device (11) connected to the integrated controller (9) to monitor the operation of the co-fired power generation system. In claim 1,
The GVU (4) receives a signal from the integrated controller (9) to supply gas to the co-fired engine (1), and is located between the LNG base (2) and the double pipe (3) to block the gas supply in an emergency. A natural gas co-fired power generation system comprising an installed gas supply valve (41). In claim 1,
The GVU (4) receives a signal from the integrated controller (9) and closes during gas supply or co-firing operation, and opens when gas leaks, and is installed on one side of the inner pipe (31) to discharge natural gas to the outside. (42) A natural gas co-fired power generation system comprising: In claim 1,
The GVU (4) receives a signal from the integrated controller (9) and closes during gas supply and co-firing operation, and opens when gas leaks, an emergency nitrogen supply valve installed on one side of the outer pipe (32) to supply nitrogen for purging. (43) A natural gas co-fired power generation system comprising: In claim 1,
The GVU (4) receives a signal from the integrated controller (9) and operates the outer pipe (32) to discharge nitrogen flowing between the inner pipe (31) and the outer pipe (32) to the outside of the room of the co-fired engine (1). A natural gas co-fired power generation system characterized by including a nitrogen purging valve (44) installed on one side of the. In claim 1,
The nitrogen generator (7) supplies nitrogen to the space between the inner pipe (31) and the outer pipe (32) and for purging, or supplies nitrogen to the intake system of the co-fired engine (1). system. In claim 1,
A natural gas co-fired power generation system, characterized in that an oxygen compressor (73) that operates by receiving a signal from the integrated controller (9) is installed between the nitrogen generator (7) and the oxygen tank (71). In claim 1,
The oxygen supply valve 72 receives a signal from the integrated controller 9 for oxygen generated and stored in the nitrogen generator 7 and controls the input of oxygen in the oxygen tank 71 into the co-fired engine 1. A natural gas co-fired power generation system characterized by In claim 1,
The nitrogen supply valve (10) receives a signal from the integrated controller (9) to supply nitrogen generated and stored in the nitrogen generator (7) between the inner pipe (31) and the outer pipe (32) or purges the nitrogen generated and stored in the nitrogen generator (7) between the inner pipe (31) and the outer pipe (32). A natural gas co-fired power generation system characterized by supplying conscripted nitrogen. In claim 1,
The gas operation monitoring device 11 receives signals from the nitrogen gas pressure sensor 51, the gas leak detection sensor 8, and the integrated controller 9 to determine whether gas supply is normal and to generate an alarm when gas leaks. A natural gas co-firing power generation system characterized by switching from diesel operation to co-firing operation while checking the gas supply and leakage status in the power generation system in real time. An engine starting step (S100) of providing a start signal to the co-firing engine (1) through the integrated controller (9) when the signal received from each facility of the co-firing power generation system is normal; The inner pipe (31) of the double pipe (3) connecting between the co-firing engine (1) or the co-firing engine (1) and the LNG base (2) under the control of the integrated controller (9) before starting the co-firing engine (1). A system purging step (S200) of purging the remaining natural gas; A diesel operation step (S300) in which the co-fired engine (1) proceeds to diesel operation after completing the system purging step (S200); An oxygen supply step (S400) in which oxygen is supplied simultaneously with startup in the diesel operation step (S300); In the diesel operation step (S300), the co-firing engine 1 is raised to a load capable of switching the operation mode, and when the signals received from each device of the co-firing power generation system are normal, the operation mode is manually switched by the driver's selection to enable co-firing. A mixed-fired operation stage (S500) that proceeds with driving; Simultaneously with the progress of the co-firing operation step (S500), when natural gas is supplied to the co-firing engine (1) through the inner pipe (31) of the double pipe (3) under the control of the integrated controller (9), the nitrogen generator (7) ) a nitrogen supply step (S600) of supplying nitrogen between the inner pipe 31 and the outer pipe 32 of the double pipe (3); After performing the co-firing operation step (S500), a gas leak detection step (S700) of detecting a gas leak under the control of the integrated controller (9); The nitrogen supply step (S600) During the process, if the amount of nitrogen in the nitrogen tank 70 falls below a certain level, a nitrogen generator operation step (S800) of stopping the operation of the nitrogen generator 7 under the control of the integrated controller 9; A natural gas co-fired power generation system control method, characterized in that. In claim 11,
A natural gas co-firing power generation system control method, characterized in that the diesel operation step (S300) is operated until switching to co-firing operation through the gas operation monitoring device (11). In claim 11,
A method of controlling a natural gas co-firing power generation system, characterized in that the oxygen supply in the oxygen supply step (S400) is supplied up to a load capable of switching the operation mode after starting the co-firing engine (1). In claim 11,
The gas leak detection step (S700) is performed when nitrogen flowing between the inner pipe 31 and the outer pipe 32 of the double pipe 3 is discharged to the outside through the outlet of the outer pipe 32. A gas leak detection sensor ( 8) A natural gas co-fired power generation system control method characterized by detecting gas leaks. In claim 11,
The gas leak detection step (S700) is performed by detecting nitrogen flowing between the inner pipe 31 and the outer pipe 32 of the double pipe 3 by the nitrogen gas pressure sensor 51 of the GVU 4 installed in the double pipe 3. A natural gas co-fired power generation system control method characterized by detecting pressure fluctuations due to natural gas leakage or detecting gas leakage by measuring the pressure.