JP2012002199A - Internal combustion engine stationary power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both of improvement in energy efficiency and higher reliability in an internal combustion engine stationary power generation system.SOLUTION: The internal combustion engine stationary power generation system includes an internal combustion engine (1), a rotational driving body (3), a steam generating means (9) recovering the waste heat of the internal combustion engine to generate steam, turbines (6, 7) that can be driven by introducing the generated steam or exhaust gas, and a power generator (8) that can generate electricity with the rotation driving of the turbines. The system includes an induction motor (2) connected between the output shaft of the internal combustion engine and the input shaft of the rotation driving body, that can output assist torque for the internal combustion engine by electric power generated by the generator, and can generate electricity by using the output of the internal combustion engine.

Description

  The present invention relates to an internal combustion engine stationary power generation system that uses exhaust heat of an internal combustion engine to generate electric power in a facility such as a factory, and more particularly to an internal combustion engine and a rotation coupled to the output shaft of the internal combustion engine. A driving body, steam generating means for recovering exhaust heat contained in the exhaust gas of the internal combustion engine to generate steam, a turbine that can be driven by introducing the generated steam or the exhaust gas, and the turbine The present invention relates to a technical field of an internal combustion engine stationary power generation system including a generator connected to an output shaft and capable of generating electric power in accordance with the rotational drive of the turbine.

  In the power generation system, an exhaust gas economizer is installed using the exhaust gas of the internal combustion engine, and heat generated from the exhaust gas that has been worked in the main engine is exchanged for heat to drive the steam turbine to generate power. There is a system in which a generator is provided and a shaft generator is rotated by the output of the internal combustion engine to generate power. Such power generation systems include those configured mainly with internal combustion engines that are installed stationary in facilities such as factories, and those that are being researched and developed as energy-saving technologies for ships.

  There exists patent document 1 as an example applied to the ship. Patent Document 1 discloses a technique for driving a gas turbine using exhaust gas from an internal combustion engine to cover a part of inboard load power.

JP 2007-1339 A

  In this type of power generation system configured mainly with an internal combustion engine, energy efficiency in the system is improved by converting the exhaust heat contained in the exhaust gas of the internal combustion engine into power. Here, in an internal combustion engine stationary power generation system, for example, a rotary drive body such as various compressors and pumps installed in a facility can be considered as a drive target using the generated power. There is not a little energy loss when performing. Considering that the rotary drive body to which power is supplied rotates in the same manner as the internal combustion engine, power conversion is not performed without directly using the rotational drive energy of the internal combustion engine for the rotary drive of the rotary drive body. There is a technical problem in that the use of the connection is wasteful from the viewpoint of the energy efficiency of the system.

  In addition, even with the technique disclosed in Patent Document 1, it is not possible to say that the energy efficiency of this type of power generation system is sufficient. Therefore, the actual situation is that further improvement of energy efficiency is required as a general request.

  In a stationary power generation system of an internal combustion engine, a fluid machine such as a compressor or a pump, which is a kind of driven rotational drive body, is provided in a factory for generating air pressure in the factory and is normally electrically driven. However, when the factory is closed at night, its use is greatly reduced, but for safety reasons, it cannot be completely stopped. For this reason, in an internal combustion engine stationary power generation system, it is common to install an auxiliary generator for emergencies such as when an internal combustion engine malfunction occurs. However, the installation of the auxiliary generator has a technical problem that it takes extra site and cost.

  The present invention has been made in view of, for example, the above-described problems, and an object thereof is to provide an internal combustion engine stationary power generation system having high energy efficiency and excellent reliability.

  In order to solve the above problems, an internal combustion engine stationary power generation system of the present invention recovers exhaust heat contained in exhaust gas of the internal combustion engine, a rotary drive connected to the output shaft of the internal combustion engine, and the internal combustion engine. Steam generating means for generating steam, a turbine that can be driven by introducing the generated steam or the exhaust gas, and an output shaft of the turbine that is connected to the turbine so that power can be generated when the turbine is rotationally driven. An internal combustion engine stationary power generation system including a generator, wherein the internal combustion engine is connected between an output shaft of the internal combustion engine and an input shaft of the rotary drive body, and uses electric power generated by the generator. Can output an assist torque for assisting the rotational drive of the rotary drive body, and can generate electric power by utilizing at least a part of the output of the internal combustion engine. Characterized in that it comprises an electrically motor.

  One aspect of the internal combustion engine stationary power generation system of the present invention is characterized by further comprising power transmission means for transmitting the power generated by the generator and the induction motor to an external power transmission network.

  In another aspect of the internal combustion engine stationary power generation system of the present invention, it further comprises power receiving means for receiving power from an external power transmission network, and driving the induction motor using the received power, An assist torque for assisting the rotational drive of the rotary drive body by the internal combustion engine is output.

  In another aspect of the internal combustion engine stationary power generation system of the present invention, the induction motor and a storage battery capable of storing the electric power generated by the generator are further provided.

  In another aspect of the internal combustion engine stationary power generation system of the present invention, feedback control means for feeding back a load value of the internal combustion engine based on a fuel injection amount required for the internal combustion engine to a target load value, and the internal combustion engine stationary type A power surplus state determination unit that detects surplus power generated in the power generation system and determines a power surplus, and determines whether the power surplus state is determined by the power surplus state determination unit. A feedforward control means comprising engine output calculation means for calculating engine output based on the output, and corrected fuel injection amount calculation means for calculating fuel injection amount based on the engine output and load value; The fuel injection amount calculated by the feedforward control means is subtracted from the fuel injection amount by It is characterized in.

  According to the internal combustion engine stationary power generation system according to the present invention, the rotary drive body is mechanically coupled to the output shaft of the internal combustion engine via the induction motor, so that power is generated in the internal combustion engine stationary power generation system. Compared with the case where the rotary drive body is electrically driven using electric power, there is less loss during power conversion, and a highly efficient power generation system can be realized.

  In addition, the induction motor can output assist torque for assisting the operation of the rotary drive body that is basically driven by the internal combustion engine by using the electric power generated by the generator. That is, the exhaust heat of the internal combustion engine can be substantially reused by driving the induction motor using the electric power generated using the exhaust heat in the exhaust gas of the internal combustion engine as a power source. Therefore, the energy efficiency of the internal combustion engine stationary power generation system can be further enhanced. In addition, driving the induction motor using the electric power obtained by the power generation in the internal combustion engine stationary power generation system as a power source contributes to reducing the load on the internal combustion engine at the same time, thus reducing the fuel consumption of the internal combustion engine. You can also.

  Furthermore, since the induction motor can generate electric power by using at least a part of the output of the internal combustion engine, for example, the output amount of the internal combustion engine with respect to the output amount required for driving the rotary drive body. Is excessive, the power can be converted by generating power using the surplus output of the internal combustion engine, and the surplus output of the internal combustion engine can be used effectively without wasting it.

1 is a block diagram showing an overall configuration of an internal combustion engine stationary power generation system according to a first embodiment. In 1st Embodiment, it is an example of the block diagram which shows the whole structure of the internal combustion engine stationary power generation system provided with the power transmission / reception means with the external electric power network. In 1st Embodiment, it is an example of the block diagram which shows the whole structure of the internal combustion engine stationary power generation system provided with the storage battery. It is a block diagram which shows the operation control of the internal combustion engine stationary power generation system which concerns on 2nd Embodiment. It is a figure which shows the (a) map A and (b) map B in 2nd Embodiment. It is a block diagram which shows the operation | movement flow of the power surplus state determination means in 2nd Embodiment.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.
<First Embodiment>

  First, an overall configuration of an internal combustion engine stationary power generation system (hereinafter referred to as “power generation system” as appropriate) according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the overall configuration of the power generation system according to the present embodiment.

  The power generation system includes an engine 1 which is an example of a stationary internal combustion engine capable of supplying power by burning fuel, an induction motor 2 connected to the output shaft of the engine 1, and the engine 1 via the induction motor 2. Rotation drive body 3 that rotates in response to output, supercharger 4 that compresses air supplied to engine 1, cooler 5 that cools air from supercharger 4, exhaust gas economizer 9, induction An in-facility power system 11 supplied by the electric motor 2 and the generator 8 is configured.

  The engine 1 burns fuel, thereby rotating the rotational drive body 3 via the induction motor 2 connected to the output shaft and discharging exhaust gas. The engine 1 is a kind of internal combustion engine, and is typically a multi-cylinder engine having a plurality of cylinders, and is a stationary engine provided stationary in a facility where a power generation system is installed. A clutch mechanism and a transmission gear mechanism (not shown) are provided between the engine 1 and the induction motor 2, and the output of the engine 1 is induced by appropriately changing the connection state and gear ratio. It is configured to be able to transmit to the electric motor 2 side at a predetermined rate.

  The exhaust gas from the engine 1 is supplied to the exhaust gas economizer 9 via the supercharger 4. In the supercharger 4, the air supplied to the engine 1 is compressed, and the temperature and pressure of the air are increased.

  A condenser 12 is provided at the rear stage of the steam turbine 7, and the steam that has driven the turbine in the steam turbine 7 is returned to the water by the condenser 12. The water generated by the condenser 12 is supplied to the exhaust gas economizer 9 after the air from the supercharger 4 is cooled by the cooler 5. In the cooler 5, for example, water is passed through the fins, and heat is exchanged with the air through the fins, thereby cooling. In FIG. 1, the circulation path of steam and water is indicated by a dotted line.

  In the exhaust gas economizer 9, steam is generated based on the water supplied from the cooler 5 using the exhaust gas discharged from the engine 1 and supplied via the supercharger 4 or the gas turbine 6. The steam generated by the exhaust gas economizer 9 drives the steam turbine 7, rotates the generator 8 together with the power of the gas turbine 6, and supplies power to the in-facility power system 11.

  The rotary drive body 3 is a rotated body connected to the output shaft of the engine 1 via the induction motor 2. For example, a rotationally driven part such as a compressor or a pump provided in a facility where the power generation system is installed is used. Various types of equipment. The rotational drive body 3 is rotationally driven by being connected to the output shaft of the engine 1 via the induction motor 2.

  As described above, the rotary drive body 3 is generally electrically driven by being supplied with power from the in-facility power system 11 generated in this type of power generation system. In other words, conventionally, the rotational motion of the engine 1 is once converted into electric power and then supplied to the rotational driving body 3. For this reason, conversion loss occurs during power conversion, and the driving efficiency of the rotary drive 3 is not good in terms of energy. In that respect, in the power generation system according to the present embodiment, since the rotary drive body 3 is connected to the output shaft of the engine 1 via the induction motor 2, the rotary drive of the engine 1 is mechanically used as it is. Therefore, the energy in the power generation system can be used effectively. That is, in the present embodiment, the rotary drive body 3 can be mechanically driven according to the rotation of the engine 1 without power conversion, so that a power generation system with little energy loss can be realized.

  The induction motor 2 can transmit the output torque of the engine 1 to the rotary drive body 3 side through a clutch mechanism and a transmission gear mechanism (not shown). For example, when the output torque and rotational speed of the engine 1 are different from the torque and rotational speed required to drive the rotary drive 3, the clutch connection state and gear ratio are changed as appropriate so that they match. It is configured to be able to.

  The induction motor 2 can also function as an assist motor for the engine 1 using the electric power generated by the generator 8 as a power source. For example, when the output torque of the engine 1 for driving the rotary drive body 3 is insufficient, the induction motor 2 supplies assist torque to the rotary drive body 3 (or the output shaft of the engine 1). Thus, the engine 1 can be assisted. As described above, in the power generation system according to the present embodiment, the power can be reused by driving the induction motor 3 using the electric power generated by the exhaust heat contained in the exhaust gas of the engine 1. Efficiency can be further improved.

  The engine 1 functions as a power source of the power generation system by burning fuel. Here, the fuel of the engine 1 includes a risk that the price fluctuates greatly. Therefore, in this type of power generation system, there is a general request to operate a highly efficient power generation system while reducing the risk of the price fluctuation. In response to such a request, the power generation system according to the present embodiment generates power using exhaust heat contained in the exhaust gas from the engine 1, and uses the surplus power obtained by the power generation as a power source for the induction motor 2. By driving the, the assist torque is supplied to the output shaft of the engine 1, thereby reducing the load on the engine 1 and effectively suppressing the fuel consumption of the engine 1.

  The induction motor 2 can also function as a generator. When the output amount of the engine 1 is excessive with respect to the output amount required to drive the rotary drive 3, the surplus output of the engine 1 is used to generate power in the induction motor 2, Since it can supply as a part of electric power grid | system 11, it can utilize as electric power, without wasting the surplus output of the engine 1. FIG.

  Subsequently, the power generation system according to the present embodiment purchases at least a part of the in-facility power system 11 from the external power transmission network as shown by reference numeral 13 in FIG. Can be sold via an external power grid. That is, reference numeral 13 indicates an example of “power transmitting means” and “power receiving means” according to the present invention. FIG. 2 is an example of a block diagram illustrating an overall configuration of a power generation system including an external power network and power transmission / reception means.

  First, a description will be given of a case where the required power amount of the in-facility power system 11 is high and a part thereof is purchased by purchasing power from an external power transmission network. In this case, reference numeral 13 in FIG. 2 functions as a “power receiving unit” according to the present invention. As described in the background art, in this type of power generation system, an auxiliary generator is generally provided in case the engine 1 that is the main power source of the rotary drive 3 fails. However, the auxiliary generator requires a large site and cost for installation. Thus, in the power generation system according to the present embodiment, the rotary drive body 3 can be driven without using power from the engine 1 by driving the induction motor 2 using electric power purchased from the outside. . That is, even if an auxiliary generator is not provided, it is possible to respond by driving the induction motor 2 in an emergency such as when the engine 1 fails.

  Next, the case where the electric power generated in the power generation system is sold to the external power transmission network will be described. In this case, the code | symbol 13 of FIG. 2 functions as a "power transmission means" which concerns on this invention. For example, if an in-facility compressor or the like is employed as the rotary driving body 3, the torque for driving such a compressor or the like may be relatively small, so that the output of the engine 1 is excessive with respect to the required output. There is a tendency to become. In such a case, surplus energy can be used without waste by converting the excess amount of the output of the engine 1 by causing the induction motor 2 to function as a generator and selling it. .

  Further, in order to effectively use surplus energy in the power generation system, a storage battery 14 may be provided in the system as shown in FIG. FIG. 3 is an example of a block diagram illustrating the overall configuration of the power generation system including the storage battery 14. In this case, the surplus energy converted by the induction motor 2 can be stored in the storage battery 14 in the form of electric power. Therefore, when the energy is insufficient to drive the rotary drive body 3 in the power generation system at a later date, the assist motor 2 is driven by using the electric power stored in the storage battery 14, thereby providing assist torque to the engine 1. Can be supplied and assisted. This example is also advantageous in that it is not necessary to provide an emergency auxiliary generator.

In addition, as another merit when the storage battery 14 is provided, for example, during the daytime when the power load in the facility is large, the engine 1 is stored in the storage battery 14 in advance during the day when the power load in the facility is reduced. And the rotational drive body 3 can be driven using only the induction motor 2 as a power source by using the electric power stored in the storage battery 14. Thereby, the operating time of the engine 1 can be reduced and the fuel consumption of the engine 1 can be effectively suppressed.
Second Embodiment

  In the above power generation system, the gas turbine 6, the steam turbine 7, and the induction motor 2 cover the power in the facility. Here, when surplus power is generated due to a sudden decrease in the power load in the facility, the surplus power generated is supplied to the induction motor 2, the assist torque by the induction motor 2 becomes a disturbance, and the rotary drive body 3 suddenly There is a risk of accelerating.

  Therefore, in the power generation system according to the second embodiment, such a fear can be effectively eliminated by performing the control shown in FIG. FIG. 4 is a block diagram illustrating operation control of the power generation system according to the second embodiment. In addition, since the whole structure of the electric power generation system which concerns on 2nd Embodiment is common in 1st Embodiment, suppose that detailed description is abbreviate | omitted here.

  When the rotational drive body 3 is rotationally driven at a predetermined rotational speed, an appropriate load is applied to the rotational drive body 3. That is, in order to drive the rotational drive body 3 at a predetermined rotational speed, it is necessary to calculate a target load value applied to the rotational drive body.

  As shown in FIG. 4, first, a rotational drive body load command is given in order to rotationally drive the rotational drive body 3 with a target load value. The rotary drive load command is converted into a fuel injection amount by the controller 21 and a fuel injection command is given to the engine 22.

  On the other hand, when the surplus power amount generated by the sudden decrease in the power load in the facility is detected and it is determined that the power surplus is present, the engine output corresponding to the output of the induction motor 2 according to the map A described later is calculated as an engine output 25. Then, a fuel injection amount calculation 26 calculates a fuel injection amount corresponding to the engine load value and engine output according to the map B. The fuel injection amount determined by the surplus power is transmitted to the actuator 27, and is subtracted from the fuel injection command of the controller 21, and the subtracted and corrected fuel injection command is given to the engine 22. In this way, the fuel injection amount to be finally supplied to the engine is controlled by the above-described feedforward control.

  In FIG. 4, a mechanically controlled engine that mechanically controls fuel injection is used as the engine 22, but an electronically controlled engine is also preferably used.

  Subsequently, after adding the assist torque from the induction motor 2 and subtracting the fluid load (for example, the air resistance passing through the wings of the compressor which is an example of the rotary drive 3), the load value calculation 23 is performed and fed back. The difference between the target load value of the rotary drive 3 and the actual load value is calculated by subtraction 24.

  In the engine output calculation 25 and the fuel injection amount calculation 26 described above, calculation is performed using maps A and B shown in FIGS. 5A and 5B, which are created in advance. A map A in FIG. 5A is a map that can calculate the engine output corresponding to the output of the induction motor 2 (see FIG. 1), and is shown as a two-dimensional map. Further, a map B in FIG. 5B is a map capable of calculating the fuel injection amount corresponding to the engine load value and the engine output, and is shown as a three-dimensional map.

  As described above, since the output of the induction motor 2 can be directly detected, the fuel injection amount can be calculated from the maps A and B shown in FIGS. In addition, you may calculate not only by the calculation by a map but by the numerical formula model using a conversion factor one by one.

  Moreover, the determination about the power surplus state which starts the control shown in FIG. 4 is determined by the power surplus state determination means shown in FIG.

  The power surplus state determination means first calculates the required power in the facility from the voltage and current value in the required power calculation 31 in the facility. On the other hand, in this system, as shown in FIG. 1, the sum of the power generated by the generator 8 and the induction motor 2 is the power supply. Therefore, surplus power can be obtained by subtracting the required power in the facility from the sum of the power generated by the generator 8 and the induction motor 2. Then, in the power surplus state determination 30, the obtained surplus power is compared with a predetermined threshold, and when the surplus power exceeds the threshold, it is determined as a power surplus state, and the control shown in FIG. 4 is started. .

  From the above, in the power generation system according to the present embodiment, feedforward control is used so that the load value of the rotary drive body 3 becomes the target value when surplus power is detected and it is determined that the power surplus state is present. By controlling the fuel injection amount of the engine, the influence of disturbance can be effectively suppressed even when the power load in the facility is suddenly reduced.

  On the contrary, various control can be considered also when the power load in the facility increases rapidly. For example, the output of the engine 1 maintains the rated output, but the shortage is based on the power stored in the storage battery 14. It is good to supplement. In this case, since the electric power stored in the storage battery 14 is generated by converting the surplus energy by the generator 8 and the induction motor 2, it is effectively utilized without wasting energy in the power generation system. It becomes.

  As described above, the power generation system according to the present embodiment can provide an internal combustion engine stationary power generation system that is high in energy efficiency and excellent in reliability.

  The present invention includes, for example, an internal combustion engine, a rotary drive connected to an output shaft of the internal combustion engine, steam generation means for recovering exhaust heat contained in exhaust gas of the internal combustion engine and generating steam, and the generation For use in an internal combustion engine stationary power generation system including a turbine that can be driven by introducing the generated steam or the exhaust gas, and a generator that is connected to an output shaft of the turbine and that can generate electric power when the turbine is driven to rotate Is possible.

DESCRIPTION OF SYMBOLS 1 Engine 2 Induction motor 3 Rotating drive body 4 Supercharger 5 Cooler 6 Gas turbine 7 Steam turbine 8 Generator 9 Exhaust gas economizer 11 Power in facility 12 Condenser 14 Storage battery 21 Controller 25 Engine output calculation 26 Fuel injection amount Calculation

Claims (5)

An internal combustion engine, a rotary drive connected to the output shaft of the internal combustion engine, steam generation means for recovering exhaust heat contained in the exhaust gas of the internal combustion engine and generating steam, and the generated steam or the In an internal combustion engine stationary power generation system comprising a turbine that can be driven by introducing exhaust gas, and a generator that is connected to an output shaft of the turbine and that can generate electric power as the turbine is driven to rotate.
Assisted between the output shaft of the internal combustion engine and the input shaft of the rotary drive body, and assisting the rotational drive of the rotary drive body by the internal combustion engine by using the electric power generated by the generator An internal combustion engine stationary power generation system comprising an induction motor capable of outputting an assist torque and capable of generating power by utilizing at least a part of the output of the internal combustion engine.   The internal combustion engine stationary power generation system according to claim 1, further comprising power transmission means for transmitting electric power generated by the generator and the induction motor to an external power transmission network. A power receiving means for receiving power from an external power grid;
The assist torque for assisting the rotational drive of the rotary drive body by the internal combustion engine is output by driving the induction motor using the received electric power. The internal combustion engine stationary power generation system described.   The internal combustion engine stationary power generation system according to any one of claims 1 to 3, further comprising a storage battery capable of storing electric power generated by the induction motor and the generator. Feedback control means for feeding back a load value of the internal combustion engine based on a fuel injection amount required for the internal combustion engine to a target load value;
Power surplus state determination means for detecting surplus power generated in the internal combustion engine stationary power generation system and determining power surplus; and
Engine output calculating means for determining whether the power surplus state is determined by the power surplus state determining means and calculating the engine output based on the output of the induction motor if the power surplus state;
Feedforward control means comprising correction fuel injection amount calculation means for calculating a fuel injection amount based on the engine output and a load value;
5. The combustion injection amount is corrected by subtracting a fuel injection amount calculated by the feedforward control unit from a fuel injection amount by the feedback control unit. 6. The internal combustion engine stationary power generation system.

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