JP2883341B2 - Structure of steam turbine, steam generation system for steam turbine, and operation method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has been modified so as to be able to expand the range of heat sources used, and is configured to be suitable for using an unstable heat source having a relatively low calorie. A steam turbine structure, and a steam generation system improved so as to be suitable for generating steam for driving the steam turbine by using an unstable heat source having a relatively low calorie;
Also, the present invention relates to an operation method of the steam generation system.

2. Description of the Related Art Conventionally, steam turbines have been improved continuously starting from non-reheat steam turbines, and reheat steam turbines have been developed to improve the efficiency of steam turbine plants.

These conventional steam turbines are mainly configured and operated on the premise of a high calorie and stable supply heat source mainly using fossil fuel as a heat source.

In a conventional steam turbine plant, the non-reheated steam turbine system is operated independently or the reheated steam turbine system is operated alone, and there is no precedent for using both the reheated and non-reheated steam turbine systems.

In a cogeneration steam turbine, a control valve is provided between a high-pressure section and an intermediate-pressure section to control the flow rate of steam flowing downstream. Regarding this kind of technology, Japanese Patent Publication No. 60-44
No. 481 is known.

[Problems to be solved by the invention]

Technical improvements related to conventional steam turbines have been focused on improving thermal efficiency and reducing the unit cost of generated power using coal or petroleum as an energy source.

However, given the limited reserves of these fossil fuels and the fact that their imports and prices are susceptible to international affairs, serious efforts are being made to expand the range of fuels that can be used. Is requested. This is a hundred years of contribution to the development of Japan's industry.

However, solar heat energy, garbage incineration energy, crude coal energy, crude liquid energy, and crude gas energy (hereinafter referred to as future energy), which have not been put to practical use, have the advantage that they are inexpensive, but they have each been put into practical use. There was a cause that hindered.

Unless the cause of such a problem is clarified and the problem is eliminated, the practical stage of the future energy source cannot be reached.

The “unusability” common to future energy sources can be summarized as follows: (i) The calorific value is relatively low.

(Ii) The calorific value is unstable.

It is.

The present invention has been made in view of such circumstances, and is a steam turbine structure suitable for using an inexpensive but unstable low-calorie heat source, and a steam generation system for a steam turbine suitable for using an unstable low-calorie heat source. And an operation method thereof.

[Means for solving the problem]

The basic principle of the structure of the present invention created as a steam turbine suitable for a future energy source which is less caloric and unstable than fuel for a conventional thermal power plant is briefly described as follows.

(A) If the amount of generated heat is unstable, the temperature and pressure of the generated steam also become unstable. In order to cope with such a problem, the steam turbine structure of the present invention enables the operation as a reheated steam turbine and the operation as a non-reheated steam turbine to be performed quickly.
The structure is such that it can be easily switched and the loss of steam energy when operating as a non-reheat turbine can be reduced. As a specific configuration, the steam flow direction of the high-pressure section and the steam flow direction of the medium-pressure section are equalized and arranged, and the high-pressure section final stage and the medium-pressure section first stage are brought close to each other. A partition plate for preventing the flow of steam is provided between the partition plate and the first stage of the intermediate-pressure section; an opening is provided in the partition plate;
A high-medium pressure communication valve that can be opened is installed, and a high-pressure part downstream end opening connected to a steam inlet of the heater reheating part is provided at a downstream end of the high-pressure part partitioned by the partition plate. At the upstream end of the intermediate pressure section defined by the above, an intermediate pressure section upstream end opening connected to the steam outlet of the heater reheating section is provided, and a return steam stop valve is provided in the connection pipe.

Further, in the above configuration, the high / intermediate pressure communication valve can be omitted.

Further, as described above, the steam generation system of the present invention created for generating steam using the low-calorie and unstable future energy source and supplying the steam to the steam turbine has the first heating system using the future energy source. And a second heater using a conventional energy source.

The method of the present invention created to operate this side-mounted steam generation system operates the first heater using a future energy source in a steady state, and the steam generated by the first heater is operated. If the amount of energy is insufficient, the second heater is operated using a conventional energy source.

[Action]

As described above, when the steam flow direction of the high pressure section and the steam flow direction of the medium pressure section are set to be the same, the steam flow path is short when supplying the exhaust gas of the high pressure section to the medium pressure section without reheating, Low loss of steam energy. In addition, the configuration of the steam turbine as a whole (combining the high-pressure section and the medium-pressure section) is simple and compact.

When using such a configuration, if a partition plate and valve means are provided between the high-pressure section and the medium-pressure section, switching between the pattern as the reheat type and the pattern as the non-reheat type can be easily and reliably performed. Done.

In addition, the above-described first heater and second heater are provided side by side, and in the steady state, the unit price of generated steam is reduced by using an inexpensive future energy source, and the instability peculiar to the future energy source is reduced. Therefore, when the calorie of the generated steam is insufficient, the second heater is operated by using the conventional energy source (high quality coal, high quality oil, high quality natural gas) to compensate for the insufficient energy (even if the energy is partially compensated). Well, you may switch entirely). Thereby, the supply of the necessary steam power to the steam turbine can be maintained.

Embodiment FIG. 1 is a longitudinal sectional view showing one embodiment of a steam turbine structure according to the present invention.

The main steam is supplied to the first stage nozzle 14 of the high-pressure section 16 through the turbine steam chamber 11, the steam control valve 12, and the nozzle steam chamber 13, and is blown to the first stage rotor blades 15. Thereafter, the work is performed while flowing toward the right side of the figure to the final stage 19 of the high pressure section.

In the drawing, reference numeral 18 denotes an intermediate pressure portion, and reference numeral 21 denotes a first stage thereof. As described above, the medium pressure section 18 is also set so that the flowing direction of the steam is rightward in the drawing.

As a result of making the steam flow direction of the high pressure section 16 and the steam flow direction of the intermediate pressure section 18 the same, the high pressure section final stage 19 and the intermediate pressure section first stage 21 are opposed to each other in close proximity.

A partition plate 20 is provided in such a manner as to partition the facing portion, and a high / medium pressure communication valve 17 having a structure capable of communicating or blocking the high / medium pressure portions partitioned by the partition plate is provided.

The casing of the high-pressure unit 16 of the present example has a single-layer structure. The high-pressure section 16 of the present example receives the supply of main steam generated by a low-calorie future energy source, so that it can withstand the pressure without having a double structure, and by employing a single structure, Shape and dimensions are compact.

The high / medium pressure communication valve 17 is not a stop valve type that can perform only ON / OFF control, but is constituted by a regulating valve having a flow rate control function.

On both sides through the partition plate 20, that is, the high-pressure section 16
A high-pressure section downstream end opening 22 and a medium-pressure section upstream end opening 23 are provided at the downstream end and the intermediate pressure section 18 at the upstream end, respectively.

The high-pressure section downstream end opening 22 is connected to a steam inlet of a heater reheating section 27 via a reheat steam main stop valve 24.

Further, the intermediate pressure portion upstream end opening 23 is connected to a steam outlet of the heater reheating unit 27 via a return steam stop valve 26 and a return steam regulating valve 25 having a flow rate control function in series. .

When the high-medium pressure communication valve 17 is closed, the steam that has worked in the high-pressure section 16 passes through the high-pressure section final stage 19, and then passes through the high-pressure section downstream end opening 22 to the steam inlet of the heater reheating section 27. Be guided.

The reheated steam reheated here is the intermediate pressure section upstream end opening 23
Through to the medium pressure section 18. That is, the steam turbine is operated for reheating.

When the high / medium pressure communication valve 17 is opened, the steam that has worked in the high pressure section 16 flows through the high / medium pressure communication valve 17 and passes through the medium pressure section 18.
Flows into. In this case, since the steam flow path does not pass through the steam turbine external piping, no steam energy loss occurs due to the piping.

In this case (when the high / medium pressure communication valve 17 is opened), if the return steam stop valve 26 is closed, steam does not flow to the reheating system, and non-reheating operation is performed.

The effect of the steam turbine of this example (FIG. 1) is great when applied to, for example, solar thermal power generation.

Normally, solar thermal power generation itself is naturally installed in a place where sunlight is relatively strong at all times.However, on a cloudy day or at night, there is a shortage of power that can be generated against demand, and fossil fuel For example, a method of installing a boiler based on the above is adopted. In consideration of the operation mode, in the case of operation that is always used, that is, in the case of energy originally called energy, since the calorie of the heat source is relatively low, abundant energy is used to obtain the necessary total energy (in other words, the energy density is diffused). In the case of a boiler operation of a complementary standpoint of adopting a reheat type and operating for a short time, it is preferable to adopt a simple non-reheat type while suppressing the equipment cost.

Such operations are also used in boilers that recover heat generated by garbage incineration and boilers that burn crude coal.
It is necessary to supplement with steam from a boiler used for general commercial use when not only the temperature rise is relatively low due to the moisture mixed in the garbage but also the temperature rise does not remain as planned.

If the high-to-medium pressure communication valve 17 is not a stop valve that performs a mere on / off operation, but is configured with a regulating valve having a flow control function, a mixed operation of a reheat type operation and a non-reheat type operation is performed. It is also possible.

In addition, by providing a reheat steam stop valve 24 for closing the flow of steam to the heater reheating unit in the high pressure exhaust unit, the steam flow is closed only by the return steam stop valve 26 in the case of non-reheat operation. Compared to the case, the flow of steam is the same as that of a normal non-reheat turbine, and can be systematically stabilized.

FIG. 2 shows an embodiment different from the above. Previous example (Fig. 1)
The difference from this is that no valve means is provided on the partition plate 31 that separates the high-pressure section 28 and the medium-pressure section 29, and the other configuration is similar to the previous example (FIG. 1). In this embodiment (FIG. 2), the reheat steam main stop valve 24 is unnecessary.

This example (FIG. 2) functions in the same manner as the previous example (FIG. 1) in which the high / medium pressure communication valve 17 is closed. That is, the steam that has worked in the high-pressure section 28 passes through the
The flow into the medium pressure section is blocked by 31 and the high pressure section end opening
It is sent to the heater reheating section 27 through 22 '. The high-temperature reheated steam reheated by the heater is returned to the medium pressure section through the medium pressure section end opening 23 '. Therefore, according to this embodiment, the partition plate 31 is provided between the high pressure section and the medium pressure section, and the return steam regulating valve 25 'and the return steam stop are provided between the high pressure section downstream end opening 22' and the medium pressure section upstream end opening 23 '. Valve 26 '
By providing the piping having the above structure, the flow path of the steam supplied from the high-pressure section to the medium-pressure section can be shortened, and the loss of steam energy can be reduced accordingly. It is a steam turbine structure of reheat type operation, suitable for application to a heater using a future energy source, and can be made compact in structure.

FIG. 3 is a diagram showing a case in which a future energy source (eg, waste rubber incineration heat or solar heat) having an unstable heating value and undergoing an unexpected change with time is used as a heat source to generate steam for driving a steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS It is a system diagram which shows one Example of the steam generation system based on the created this invention.

Reference numeral 6 denotes a high pressure section of the steam turbine, 7 denotes an intermediate pressure section, and 8 denotes a low pressure section.

The steam generation system of this embodiment is preferably used in combination with the steam turbine structure of the present invention shown in FIGS. 1 and 2, but can also be used in combination with a conventional reheated steam turbine.

Reference numeral 1 denotes a main steam superheater of the first heater, and 2 denotes a reheater, both of which constitute a first heater I.

Reference numeral 3 denotes a main steam superheater of the second heater, and reference numeral 4 denotes a reheater, both of which constitute a second heater II.

The first heater I uses a future energy source (for example, solar heat, waste incineration waste heat, or coarse coal) as a heat source.

The second heater II is a conventional fossil fuel (for example, LN
G, heavy oil, high-quality coal, etc.) as the heat source.

In order to operate the steam generation system of the present example, in a steady state, steam is generated by the first heater using a future energy source.

The future energy source, which is the heat source of the first heater I, will be abundant and inexpensive in the future, so that the unit price of generated steam is low in a steady state, and further, there is no concern about resource supply. However, these future energy sources generate unstable heat, such as solar heat due to changes in weather, waste incineration waste heat due to changes in waste quality and water content, and poor gaseous fuel due to changes in temperature. As the amount of heat changes, the amount, temperature, and pressure of the generated steam change, and its prediction is difficult.

When the retained energy of the generated steam decreases, the steam turbine structure shown in Fig. 1 switches between reheating operation and non-reheating operation (mixing is also possible), but depending on these operations, a complete response is not always possible. Since it is impossible, an embodiment of the operation method according to the present invention using the steam generation system (embodiment as an apparatus) of FIG. 3 configured to compensate for the shortage of the energy possessed by steam will be described below.

Steady state (a state in which the steam turbine structure according to the embodiment in FIG. 1 can cope with a change in generated steam holding energy)
In, the steam turbine is driven by the steam generated by the first heater I using a cheap and abundant future energy source as a heat source.

When the generated steam holding energy is reduced beyond the range that can be handled by the steam turbine structure according to the embodiment of FIG. 1, the conventional commercial energy source (for example, bituminous coal, LNG, heavy oil A, etc.) is used as a second heat source. Run Heater II to make up for the missing steam.

When the first heater I stops generating steam (for example, disappearance of solar heat at night, failure of flame holding in poor fuel, etc.), the steam is entirely switched to the steam generated by the second heater II. Continue operation of the steam turbine.

Thus, the steam turbine structure according to the present invention,
In combination with the steam generation system according to the present invention, it is possible to realize the use of a low-calorie and unstable future energy source.

〔The invention's effect〕

As described above, the steam turbine structure, the steam generation system for the steam turbine, and the operation method thereof according to the present invention are applicable to industrial fields (operation of a steam turbine using a low-calorie and unstable energy source). Similarly, covering the shortcomings of low calorie and unstable energy sources,
Achieve the purpose of putting it to practical use.

That is, in the steam turbine structure according to the present invention, the steam flow direction in the high-pressure section is the same as the steam flow direction in the medium-pressure section, and the high-pressure section final stage and the intermediate-pressure section first stage are brought close to each other and a partition wall is provided therebetween. Therefore, switching between reheating operation and non-reheating operation can be performed easily and with high efficiency, it is highly adaptable to changes in steam conditions, and it can be made compact, low calorie and unstable. It can adapt to changes in the generated steam conditions due to the heat source.

Further, if the operation method of the steam generation system according to the present invention is performed by the steam generation system according to the present invention, low-cost and low-cost steam can be supplied to the steam turbine using an unstable heat source in a steady state. If the energy generated by the low calorie and unstable heat source is insufficient, it can be compensated by using a normal commercial energy source.

[Brief description of the drawings]

1 and 2 are cross-sectional views each showing an embodiment of the steam turbine structure according to the present invention. FIG. 3 is a system diagram showing one embodiment of a steam generation system for a steam turbine according to the present invention. I: first heater, II: second heater, 1 ... first
, The superheated portion of the heater, 2... The reheated portion of the first heater, 3.
... A superheater section of the second heater, 4... A reheat section of the second heater, 6... A high pressure section of the steam turbine, 7.
... Low pressure section, 16 ... High pressure section of steam turbine, 17 ... High / medium pressure communication valve, 18 ... Medium pressure section, 19 ... Final stage of high pressure section, 20 ...
Partition plate, 21 ... First stage of medium pressure section, 22 ... Opening of downstream end of high pressure section,
23 …… Opening of the middle pressure section upstream end, 24 …… Reheat steam stop valve, 25
…… Return steam regulating valve, 26 …… Return steam regulating valve.

Claims (8)

(57) [Claims] 1. Steam supplied with working steam from a heater comprising a superheating section for generating steam and a reheating section for heating the steam, and having a high-pressure section, a medium-pressure section and a low-pressure section connected in a single shaft. In the turbine structure, the steam flow direction of the high-pressure section and the steam flow direction of the medium-pressure section are arranged in the same direction, and the flow of steam is prevented between the final stage of the high-pressure section and the first stage of the medium-pressure section. Then, a partition plate is provided, an opening is provided in the partition plate, and a high-to-medium pressure communication valve capable of closing and opening the opening is provided. A heater is provided at a downstream end of the high-pressure section defined by the partition plate. A high pressure section downstream end opening connected to the steam inlet of the heating section is provided, and an intermediate pressure section connected to the steam outlet of the heater reheating section at an upstream end of the medium pressure section partitioned by the partition plate. An upstream end opening is provided, and a return steam stop valve is provided in the connection pipe. It characterized the structure of the steam turbine. 2. The structure of the steam turbine according to claim 1, wherein the high-to-medium pressure communication valve is a regulating valve having a flow control function. 3. The steam turbine structure according to claim 1, wherein the turbine casing of the high-pressure valve has a single structure. 4. The steam turbine according to claim 1, wherein the high pressure section downstream end opening is connected to a heater reheating section inflow port through a reheat steam stop valve. Construction. 5. A connecting pipe provided between the outlet of the heater reheating section and the opening at the upstream end of the intermediate pressure section includes the return steam stop valve and the return steam regulating valve having a flow rate control function. The structure of the steam turbine according to claim 1, wherein the steam turbine has: 6. Steam which is supplied with working steam from a heater comprising a superheating section for generating steam and a reheating section for heating the steam, and which has a high-pressure section, a medium-pressure section and a low-pressure section connected in a single shaft. In the turbine structure, the steam flow direction of the high-pressure part and the steam flow direction of the medium-pressure part are arranged in the same manner, and a partition plate that prevents the flow of steam between the final stage of the high-pressure part and the first stage of the medium-pressure part A downstream end of a high-pressure section connected to a steam inlet of a heater reheating section at a downstream end of the high-pressure section partitioned by the partition plate, and an upstream of an intermediate-pressure section partitioned by the partition plate. At the end, an intermediate-pressure section upstream end opening connected to the steam outlet of the heater reheating section is provided, and the connecting pipe between the steam outlet of the heater reheating section and the intermediate pressure section upstream end opening is returned steam stop. Steam having a valve and a return steam regulating valve having a flow control function The structure of the turbine. 7. A first heater having a superheater for generating steam and a reheater for heating steam, using a heat source having a relatively low calorie and an unstable heat generation amount, and a steam generator. A steam generating system for a steam turbine, comprising a second heater using a heat source having a relatively high calorie and an easily reduced amount of generated heat having a superheating section for heating the steam and a reheating section for heating the steam. . 8. A first heater having a superheating section for generating steam, a reheating section for heating steam, and using a heat source having a relatively low calorie and generating an unstable amount of heat, and generating steam. Operates a steam turbine that has a superheater and a reheater that heats steam, and that is supplied with working steam from a steam generator system that includes a second heater that uses a heat source with a relatively high calorie and stable heat generation. In a steady state, operating the first heater and the second heater.
When the heater of the first heater is stopped, and the steam energy generated by the first heater is insufficient,
A method for operating a steam generation system for a steam turbine, wherein a second heater is used in combination or switched to a second heater.