JPH06307206A - Steam turbine system making use of exhaust heat - Google Patents

Abstract

PURPOSE:To enable output to be rapidly increased while being interlocked with the rapid increase in the output of an internal combustion engine by recoverying exhaust heat of the internal combustion engine so as to operate a steam turbine system. CONSTITUTION:Exhaust heat is recovered by working fluid, and by a heat exchanger 1, and steam of working fluid is taken as superheated steam so as to drive a main steam turbine 4, and the shaft output is taken out. For the transitional fixed period to when the steam generating amount of the heat exchanger 1 is followed according to the sudden change of the output of the internal combustion engine, steam in a pressure reducing chamber 51 is pressurized and sent to a superheater 3 by an electric blower 21, and a discharge pipe 54 as an exhaust part of a forcibly pressure reducing device 5 and a steam chamber of the heat exchanger 1 are connected to each other through a solenoid valve V4 to be opened when pressure in the steam chamber is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat utilizing steam turbine system for recovering the amount of heat of exhaust gas in various internal combustion engines and improving the overall energy efficiency.

An internal combustion engine typified by a gasoline engine or a diesel engine plays a major role as various power sources including a power source mounted on a land transportation engine such as an automobile and a rail car, a ship and the like.

Almost all of such internal combustion engines are fueled by petroleum, which depends on imports. Such oil is not only valuable in terms of price, but the oil resources themselves are limited, and there is a demand to save as much as possible.

[0004]

2. Description of the Related Art The total thermal efficiency of an internal combustion engine currently put into practical use is about 30 to 40%, and such an upper limit cannot be exceeded despite rigorous research and development day and night. Therefore, 1/2 or more of the fuel possession energy is wasted as loss represented by heat and sound. In particular, exhaust gas contains a large amount of heat, and unless the unused energy is utilized, a dramatic improvement in the overall thermal efficiency of the internal combustion engine cannot be achieved.

In order to effectively use such exhaust heat energy, a method for recovering exhaust heat energy in addition to electric energy is being adopted as a so-called cogeneration system in a large-scale internal combustion engine for power generation. However, since the recovered energy is in the form of heat, it cannot be used without the use of steam or hot water, and it is said to be technically and economically feasible unless it is a large internal combustion engine. Therefore, it is difficult to apply those methods to a small-medium-sized internal combustion engine for transportation mounted on a vehicle, a ship, or the like. Even if you use it,
The generated steam or the like is at most usable for heating and cooling purposes.

In view of such circumstances, the present inventor has previously proposed an exhaust heat utilizing steam turbine system in which a small turbine is driven to recover energy in order to effectively use exhaust heat energy of an internal combustion engine. (Japanese Patent Application 4
No. -352656, which is not yet known at this time, and is hereinafter referred to as a preceding exhaust heat utilization system).

As shown in FIG. 2, the prior exhaust heat utilization system applied by the applicant of the present invention is, as shown in FIG. 2, a heat exchanger 101 for heating and evaporating the working fluid by the heat quantity of the exhaust gas, and the heat exchanger. A steam pressurizer 102 that pressurizes the working fluid steam obtained in 101, a superheater 103 that reheats the outlet steam of the steam pressurizer 102, and the heater 103.
A main steam turbine 104 that is rotated by superheated steam obtained from the output of the main steam turbine to generate power, and a forced decompression device 105 connected to the exhaust side of the main steam turbine 104,
A condenser 106 for converting the steam discharged from the forced decompression device 105 into a working fluid liquid, and a backflow preventer 107 for returning the working fluid liquid obtained by the condenser 106 to the heat exchanger 101. And composed.

The steam pressurizer 102 sucks the working fluid generated by the heat exchanger 101, pressurizes it in the superheater 103 and exhausts it, and the electric blower 121 and the steam turbine blower 1 respectively.
22 and is switched by two solenoid valves V1 and V2, and vapor pressure is selectively applied by either of them. In this case, the main shaft 141 of the main steam turbine 104 is connected to any device for power recovery for the engine itself or for peripheral devices.

Further, this preceding exhaust heat utilization system is
A heat exchanger 10 provided in the middle of an exhaust pipe of an internal combustion engine from an exhaust inlet 111 to an exhaust outlet 113.
1. In particular, the exhaust vaporizes the working fluid 114 while the exhaust gas passes through the expanded heat exchange section 112, and the generated vapor causes the solenoid valve V1 to open and the solenoid valve V2 to open when the vapor shortage occurs immediately after the system operation starts. It is closed, and is introduced into the superheater 103 by the electric blower 121 via the superheated steam introducing pipe 131.

Further, the steam generated in the heat exchanger 101, on the contrary, when the system becomes a steady state, on the contrary, the solenoid valve V
The solenoid valve V1 is closed by opening the valve 2 and the steam output from the superheater 103 is introduced into the superheater 103 by the steam turbine blower 122 that operates by diverting the steam. The superheated steam exiting the superheater 103 operates the main steam turbine 104 and the small steam turbine 152 via the superheater outlet pipe 132. The small steam turbine 152 rotates the decompression blower 153 to decompress the decompression chamber 151 on the exhaust side of the main steam turbine 104.
The waste steam inside is forcedly sent to the condenser 106.

The exhaust pipe 154 of the decompression blower 153 is
It is connected to the condenser 106 via the diffusion resistance fan 108, and this exhaust steam is cooled by the cooling water flowing from the cooling water inlet 162 to the outlet 163 while passing through the steam pipe 161, and is returned to the liquid. , And becomes working fluid again via the backflow preventer 107.

In such a preceding exhaust heat utilization system attached to the internal combustion engine, when the prime mover generating exhaust gas is rapidly accelerated, the engine output sharply increases, and the exhaust temperature also sharply increases. However, there is a temporal lag in the increase in the steam generation amount of the heat exchanger 101 heated by the exhaust gas, and it is not possible to immediately follow the increase in the steam generation amount. Therefore, it is necessary to immediately follow the operation of the internal combustion engine to improve the output. For example, in applications such as auxiliary power of the engine, etc., sufficient steam is not available as a result of insufficient energy generation. Will not be possible.

[0013]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art and recovers the energy stored in the waste heat attached to mobile internal combustion engines and small and medium-sized internal combustion engines. It is an object of the present invention to provide an exhaust heat utilizing steam turbine system capable of generating sufficient energy even when the output of the internal combustion engine of the main body suddenly changes.

[0014]

The gist of the constitution of the present invention is to provide a heat exchanger for heating and evaporating a working fluid by the amount of heat of exhaust gas, and a working fluid obtained by the heat exchanger. A steam pressurizer that pressurizes steam, a superheater that reheats the outlet steam of the steam pressurizer, a main steam turbine that is rotated by superheated steam obtained from the output of the heater to generate power, and the main steam turbine. A forced decompression device connected to the exhaust side of the steam turbine, a condenser for converting the exhaust steam of the forced decompression device into a working fluid liquid, and the working fluid liquid obtained by the condenser as the heat exchange. It consists of a backflow preventer of working fluid for returning to the reactor, the steam pressurizer is an electric blower and a steam turbine blower inserted in parallel in the middle of the pipe connecting the steam chamber of the heat exchanger and the superheater. There
A steam turbine blower operating with the output steam of the superheater, and a solenoid valve inserted in the middle of each pipe of the electric blower and the steam turbine blower, immediately after the start of operation of the internal combustion engine to which this system is attached, When the output steam from the superheater is insufficient, the electric blower is operated, the corresponding solenoid valve is opened, the steam in the steam chamber of the heat exchanger is pressurized and supplied to the superheater, When the output steam of the superheater becomes sufficient, the operation of the electric blower is stopped,
And in the steam turbine system utilizing exhaust heat, which is configured to control the solenoid valve to be closed and to open the corresponding solenoid valve while closing the corresponding solenoid valve, in the exhaust side of the main steam turbine. The decompression chamber is connected to the suction side of the electric blower, a valve is inserted in the middle of the decompression chamber, and when the output of the internal combustion engine to be mounted is suddenly increased, the steam in the steam chamber of the heat exchanger becomes insufficient. An exhaust heat utilizing steam turbine system in which the electric blower is operated for an excessive period of time, and at the same time, a valve between the suction side and the decompression chamber is controlled to be opened. Can be solved.

A valve for connecting the connecting portion between the forced decompression device and the condenser to the steam chamber of the heat exchanger, and opening and closing the space between them, which is a valve between the forced decompression device and the condenser. It is also possible to insert a valve that opens when the vapor pressure in the connection rises above the vapor pressure in the vapor chamber of the heat exchanger. A steam recirculation device may be inserted outside the valve in the middle of a pipe that connects the connection between the forced decompression device and the condenser to the steam chamber of the heat exchanger. As a result, when the steam pressure in the steam chamber of the heat exchanger is lowered, the steam in the connecting portion can be increased in pressure and fed into the steam chamber.

The excessive fixed time until the steam in the steam chamber of the heat exchanger becomes insufficient is usually not more than 10 seconds.

[0017]

Since the present invention is configured as described above, exhaust heat which reaches several tens of% of the amount of heat possessed by the fuel is recovered as much as possible,
Higher efficiency of the internal combustion engine can be achieved. Exhaust gas from the internal combustion engine is introduced into a heat exchanger to heat the working fluid and generate steam. The steam thus generated is pressurized by the steam pressurizer and is heated while passing through the superheater installed in the exhaust passage to change from saturated steam to superheated steam. The superheated steam thus generated is guided to the main steam turbine to generate rotational power. Further, the split superheated steam serves as a drive source of the forced decompression device for reducing the exhaust side pressure of the main steam turbine.

The forced decompression device may be a decompression blower powered by a steam driven small turbine. The exhaust of the main steam turbine taken out through this decompression blower is changed from steam to liquid in a condenser for gas-liquid conversion. The working fluid liquid is returned to the heat exchanger. This system uses a condensate turbine that uses a working fluid in a closed system. Therefore, although water can be used as the working fluid,
A fluid having a lower boiling point can be used depending on the scale of the internal combustion engine, the application, the fuel used, and the like.

In such a construction, when the output of the target internal combustion engine is made to rise rapidly, the exhaust gas temperature rises sharply, but the amount of steam generated in the heat exchanger heated by the exhaust gas rises temporally. There is a lag and it is not possible to immediately follow up and increase the amount of steam generated.

In such a case, however, a valve inserted in the middle of a pipe connecting the decompression chamber on the exhaust side of the main steam turbine to the suction side of the electric blower is opened, and at the same time the electric blower is operated. The vapor in the decompression chamber is sucked and pressurized, and the pressurized vapor is sent to the superheater side. Thus, the steam turbine blower secures a necessary amount and pressure of steam in combination with the steam sent from the steam chamber of the heat exchanger, while the electric blower further reduces the pressure in the decompression chamber. The output of the steam turbine can be suddenly increased in association with the sudden increase in the output of the internal combustion engine.

Further, if an attempt is made to increase the output of this system due to the sudden increase in the output of the internal combustion engine, the steam in the steam chamber of the heat exchanger will be temporarily insufficient. Thus, when the vapor pressure of the connection between the forced decompression device and the condenser is relatively increased, the valve of the pipe connecting the connection and the steam chamber of the heat exchanger is opened, The steam on the side of the connecting portion is returned to the steam chamber of the heat exchanger. Even if the vapor pressure on the side of the connecting portion is insufficient, if a vapor recirculation device is inserted and placed in the middle of the pipe, it can recirculate. As a result, the outputs of the main steam turbine and the steam-driven small turbine can be rapidly increased.

The opening operation of both valves and the operation of the electric blower can be detected by a control signal or a change in the rotational speed that causes the output of the internal combustion engine to rise sharply, and can be controlled according to the detection signal. Either one may be selected depending on the degree of output sudden increase, or both may be activated simultaneously.

The use of the rotary power obtained from the main shaft of the main turbine is not limited, but for example, electrical energy can be recovered as power for a generator having an appropriate capacity suitable for the generated power. Since electric energy can be easily converted to other energy, it can be applied to any purpose. Further, it can be used to forcibly perform intake and exhaust of the internal combustion engine and increase engine output and efficiency. Further, in an auxiliary device of an internal combustion engine, for example, a vehicle-mounted internal combustion engine, it is possible to directly drive an air conditioner device, a generator, a cooling system, etc. that are driven by a shaft output.

The electric blower is driven by using a battery as a power source, and the electric power can be charged by the output of a generator operated by the surplus power generated during the steady state operation, and can be covered thereby. The same applies to vapor recirculation devices that may be provided.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a basic configuration diagram of an exhaust heat utilizing steam turbine system according to an embodiment of the present invention. In the figure, the heat exchanger 1 corresponds to a steam utilization boiler,
Exhaust inlet 11 through expanded heat exchange section 12 and exhaust outlet 13
The heat quantity of the exhaust gas held is transmitted to the working fluid 14 during the period. The heated working fluid 14 evaporates and changes to saturated vapor.

This saturated steam is taken out to the outside and the pressure is increased by the steam pressurizer 2 consisting of an electric blower 21 or a steam turbine blower 22 driven by a small steam turbine, and then exhausted via a superheater introduction pipe 31. It is adapted to be fed into the superheater 3 provided in the passage.

Whether the electric blower 21 is operated,
Whether to operate the steam turbine blower 22 is selectively performed by switching the two solenoid valves V1 and V2 according to the amount of steam generated and the steam conditions. That is, immediately after the operation of the internal combustion engine to be mounted is started, and when the output steam from the superheater 3 is insufficient, the electric blower 21 is operated to open the corresponding solenoid valve V1 to open the heat exchanger. No. 1 steam chamber is pressurized and sent to the superheater 3 through the superheater introducing pipe 31, and when the output steam of the superheater 3 becomes sufficient, the operation of the electric blower 21 is stopped, and the countermeasure is taken. The solenoid valve V1 is closed, the steam turbine 22 is operated, and the corresponding solenoid valve V2 is opened.

As described above, the saturated steam is sent through the superheater introduction pipe 31, receives heat from the exhaust gas of the internal combustion engine while passing through the superheater 3, and is passed through the superheater discharge pipe 32 as superheated steam. It is supposed to be sent out.

The superheated steam obtained from the superheater outlet pipe 32 is guided to the main steam turbine 4 and collides with turbine blades to perform work, thereby rotating the main shaft 41. The exhaust of the main steam turbine 4 that has finished the work is guided to the decompression chamber 51 of the forced decompression device 5 that is configured on the exhaust side of the main steam turbine 4.

This forced decompression device 5 is a main steam turbine 4
Has a function of expanding the steam pressure difference between the steam inlet and the steam outlet and increasing the power. The power of the forced decompression device 5 may be an electric motor, but in the present embodiment, the small steam turbine 52 is shunted by superheated steam guided to the main steam turbine 4.
The decompression blower 5 driven by this power
I am using 3. The suction side of the decompression blower 53 is the decompression chamber 5
1 and sends it to the discharge pipe 54. In addition,
The steam shunt to the small steam turbine 52 for the pressure reducing device should be designed so as to send less steam than the main steam turbine 4 by reducing the pipe diameter or providing an appropriate flow rate adjusting valve.

The steam exiting the discharge pipe 54 of the forced decompression device 5 is introduced into the condenser 6 for gas-liquid conversion, and the steam pipe 6
The liquid is cooled and liquefied by the cooling medium flowing from the cooling medium inlet 62 to the outlet 63 while passing through 1. Therefore, the liquid phase of the working fluid is taken out from below the condenser 6. Water can usually be used as the cooling medium, but when a working fluid having a low boiling point is adopted, air or other gas can be used. Also, a cooling system with a radiator can be adopted.

The working fluid liquid phase taken out as described above is returned to the heat exchanger 1 via the backflow preventer 7 as a pressure adjusting system. The backflow preventer 7 has a function of preventing backflow due to high pressure on the heat exchanger side and circulating the working fluid liquid phase. A pressure pump can also be used in combination to promote circulation. The main steam turbine 4 used in such a configuration is a condensing turbine connected to the condenser 6 via the forced decompression device 5, and the working fluid is a closed system. Therefore, any working fluid can be used in consideration of the scale of the apparatus, the exhaust temperature, the purpose of using the generated power, the influence on the environment, the economical efficiency, and the like.

Since this exhaust steam turbine system makes effective use of the exhaust heat of the internal combustion engine, it is convenient to install it at a high temperature portion before exhaust gas treatment or the like, that is, at a position close to the exhaust manifold. However, there are many possibilities depending on the selection of the working fluid, the use of the generated power, etc., and it is not limited.

As described above, such an exhaust steam turbine system can be used for various purposes, but the output of the main steam turbine 4 can be used as auxiliary power for the internal combustion engine. In such applications, it is desirable that the output of the internal combustion engine, which is the prime mover, and the shaft output of the main steam turbine 4 change correspondingly. Normally, if a sudden change in the output of an internal combustion engine during operation, especially a control for a sudden increase in output is performed, the engine output responds immediately and the exhaust gas temperature also rises rapidly, but the amount of steam generated in the heat exchanger 1 Is slightly delayed, so that the output of the main steam turbine 4 cannot rise sharply.

In such a state, the pressure reducing chamber 51 and the electric blower 21 on the exhaust side of the main steam turbine 4 are the first means for rapidly increasing the output of the main steam turbine 4.
A pipe is provided between the suction side and the suction side, and is connected via a solenoid valve V3. When it becomes necessary to rapidly increase the output of the main steam turbine 4, the solenoid valve V3 is opened and the electric blower 21 is operated at the same time. By such operation,
The vapor on the side of the decompression chamber 51 is sucked and further decompressed, and is pressurized and supplied to the superheater 3 side to pressurize the working fluid. As a result, the amount of superheated steam flowing into the main steam turbine 4 increases,
Its output rises.

As a second means for rapidly increasing the output of the main steam turbine 4, the exhaust pipe 54 connecting the forced pressure reducing device 5 and the condenser 6 and the steam chamber of the heat exchanger 1 are connected. A pipe is provided between and, and a solenoid valve V4 is inserted in the middle of the pipe. When it is necessary to rapidly increase the output of the main steam turbine 4, and when the steam pressure in the steam chamber of the heat exchanger 1 decreases, the solenoid valve V4 is opened and the discharge pipe 54 side Heat exchanger 1 for steam pressurized by decompression blower 53
Into the steam room. As a result, the lack of steam is compensated for,
The output of the main steam turbine 4 sharply increases.

These first and second means for rapidly increasing the output of the main steam turbine 4 may be either one of them depending on the required degree of output increase, or both may be operated simultaneously. it can.

[0038]

According to the present invention, several tens% of the total heat quantity of fuel, which is inevitable in the present internal combustion engines, is held.
A considerable amount of waste heat in exhaust gas can be recovered, and recovered energy can be used directly or indirectly for an appropriate load. In this case, especially for vehicles,
It is possible to quickly follow fluctuations in the output of an internal combustion engine in a variable speed internal combustion engine such as for a ship, and in particular, to rapidly increase the output.

As an example of how to use the recovered energy, generator drive, engine accessory drive, air conditioner drive,
There is a drive source for the internal combustion engine efficiency improving device. However, regardless of these enumerations, many uses can be expected as a power source of a load as appropriate.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram of an embodiment of an exhaust heat utilizing steam turbine system of the present invention.

FIG. 2 is a main part configuration diagram of a preceding exhaust heat utilization steam turbine system (not known).

[Explanation of symbols]

 1 heat exchanger 2 steam pressurizer 3 superheater 4 main steam turbine 5 forced decompression device 6 condenser 7 backflow preventer V1 solenoid valve V2 solenoid valve V3 solenoid valve V4 solenoid valve 21 electric blower 22 steam turbine blower 51 decompression chamber 53 Decompression blower 54 discharge pipe

Claims (2)

[Claims] 1. A heat exchanger (1) for heating and evaporating a working fluid by the amount of heat of exhaust gas, and a steam pressurizer (2) for pressurizing the working fluid vapor obtained by the heat exchanger (1). ), A superheater (3) that reheats the outlet steam of the steam pressurizer (2), and a main steam turbine that generates power by being rotated by the superheated steam obtained from the output of the heater (3) ( 4), a forced pressure reducing device (5) connected to the exhaust side of the main steam turbine (4), and the forced pressure reducing device (5)
Condenser for converting the exhaust steam of the vehicle to working fluid (6)
And a working fluid backflow preventer (7) for returning the working fluid liquid obtained by the condenser (6) to the heat exchanger, the steam pressurizer (2) The electric blower (21) and the steam turbine blower (22) inserted in parallel in the middle of the pipe connecting the steam chamber of the device (1) and the superheater (3), which are output steam of the superheater (3). Installation of this system, which comprises an operating steam turbine blower (22) and solenoid valves (V1) and (V2) inserted in the middle of each pipe of the electric blower (21) and the steam turbine blower (22). Immediately after the start of operation of the target internal combustion engine, when the output steam from the superheater (3) is insufficient, the electric blower (21) is operated to open the corresponding solenoid valve (V1), The steam in the steam chamber of the heat exchanger (1) is pressurized to When it is supplied to the heater (3) and the output steam of the superheater (3) becomes sufficient, the operation of the electric blower (21) is stopped and the corresponding solenoid valve (V1) is closed, and
In an exhaust heat utilizing steam turbine system in which the steam turbine blower (22) is operated and a corresponding solenoid valve (V2) is opened, pressure reduction on the exhaust side of the main steam turbine (4) The chamber (51) is connected to the suction side of the electric blower (21), a valve is inserted in the middle of the chamber, and the steam of the heat exchanger (1) when the output of the internal combustion engine to be mounted is suddenly increased. During an excessive period of time leading to a shortage of steam in the chamber, the electric blower (2
1) is operated, and at the same time, the suction side and the decompression chamber (5
An exhaust heat utilizing steam turbine system in which the valve between 1) is controlled to be opened. 2. A valve for connecting a connecting portion between the forced decompression device (5) and the condenser (6) to a steam chamber of the heat exchanger (1) and opening and closing the space therebetween. And a valve which is opened when the vapor pressure of the connection between the forced decompression device (5) and the condenser (6) rises above the vapor pressure of the vapor chamber of the heat exchanger (1). Exhaust heat utilization steam turbine system of 1.