JPH02259203A - Organic medium use power plant - Google Patents

Abstract

PURPOSE:To prevent abnormal raise of medium temperature even at power failure of a plant by providing a valve which opens at the powder failure on a piping system which connects a steam pipe communicating to a generation part of medium steam to the liquid phase side of a medium container. CONSTITUTION:A steam escape pipe 13 is provided diverged from a path which guides generated steam of a evaporator 2 to a turbine 5, and a steam escape valve 14 is arranged on its way. The other end of the steam escape pipe 13 is connected to the bottom part of a tank 10 to blow out medium steam into medium liquid as fine bubbles. And when all the powder supply in a plant is interrupted, the steam escape valve 14 is opened and the medium steam in the evaporator 2 is made escaped to the tank 10 through the steam escape pipe 13. On the other hand, the medium steam is condensed by taking heat by low-temperature medium liquid in the tank 10 to control raise of pressure in the tank 10.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention relates to a thermal cycle power plant, and in particular, to a thermal cycle power plant that removes medium steam from the cycle path when there is a complete power outage in the plant. The present invention relates to a power plant utilizing organic media that can be safely recovered into a storage container.

(Conventional technology) As a method of obtaining motive power and electric power using medium-low temperature heat such as geothermal heat or industrial waste heat, low-boiling organic media such as fluorocarbons and volatile hydrocarbons are evaporated using this heat. There is a method of driving an organic medium turbine with the steam, and one typical example of this technology is described on pages 49 to 52 of the academic journal "Turbo Machinery Vol. 15, No. 4" published by the Turbo Machinery Association. There is.

To explain the outline of this technology with reference to Fig. 2, a medium to low temperature heat source fluid 1 such as geothermal heat or industrial waste heat is heated in an evaporator 2 to evaporate a low boiling point organic medium 3, and then preheated. The medium 3 is preheated in the vessel 4 and discharged outside the plant system. The medium 3 in a liquid state is heated to near the evaporation temperature in the preheater 4 and then evaporated in the evaporator 2 to become high-energy medium vapor. This medium steam is guided to the turbine 5.
A load coupled to the turbine 5, such as a generator 6, is rotated to obtain electric power. The medium vapor whose pressure and temperature have been reduced by applying energy to the turbine 5 is discharged to the condenser 7, where it is cooled and condensed by the cooling water 8, returns to liquid form, and is then sent to the preheater 4 again by the medium pump 9. , circulate through this system. In addition, a medium storage container such as a tank 10 is provided for recovering and replenishing the medium in the system, and a medium replenishment/recovery pump 11 and a medium replenishment/recovery piping 12 are used to take in and out the medium. will be held.

(Problem to be solved by the invention) By the way, in such a plant, if there is a complete power outage in the plant due to some kind of accident, the heat source system, media system,
Since the pumps and fans in the cooling system lose power, the flow in each system cannot be maintained in a normal state. Then, because of the heat source fluid 1 remaining in the evaporator 2, the medium in the evaporator 2 is heated to an abnormally high temperature, and if this continues, the pressure in the evaporator 2 will become abnormally high. Additionally, some media may cause thermal decomposition at high temperatures, so some kind of countermeasure is required.

The increase in internal pressure can be dealt with by increasing the pressure resistance of the evaporator 2, but this increases material costs and equipment weight due to increases in the wall thickness of parts, and the resulting transportation costs and foundation work. This is unfavorable from an economic point of view, such as an increase in costs. and,
This method does not take any measures against thermal decomposition of the medium into consideration.

It is possible to release the medium vapor somewhere, but releasing it into the atmosphere is unfavorable from an environmental and economic point of view, and when releasing it to the condenser 7, the condenser 7 has no cooling/condensing function. Because of this loss, it becomes necessary to significantly increase the withstand pressure of the condenser 7, which causes the same problem as the evaporator 2.

Therefore, an object of the present invention is to reduce the internal pressure of the evaporator without releasing the medium into the atmosphere in the event of a complete power outage in the plant due to an accident, thereby improving environmental and economic efficiency. It is an object of the present invention to provide a power plant using an organic medium that does not cause the above-mentioned problems.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a steam pipe communicating with a medium steam generating section in a thermal cycle power plant that uses an organic medium as a power medium. The present invention is characterized in that it is provided with a piping system connecting the liquid phase side of the medium storage container and the liquid phase side of the medium storage container, and a valve that is opened in the event of an abnormality in the plant.

(Operation) During operation of the plant, the medium storage vessel is almost empty and usually contains a small amount of medium for replenishment.

Since the internal temperature is approximately the outside temperature, the internal pressure is its saturation pressure, which is much lower than the evaporation pressure of the evaporator. Therefore, in the event of a plant abnormality, if the evaporator and medium storage container are communicated via a piping system, the medium vapor in the evaporator will escape to the medium storage container and be released into the liquid phase of the medium storage container. As a result, the medium liquid in the medium storage container is cooled and condensed in the medium storage container. The amount of heat source fluid 1 remaining in the evaporator is limited, and the medium vapor flowing from the evaporator into the medium storage container absorbs heat as latent heat of vaporization, so an abnormal rise in the temperature inside the evaporator can be avoided. On the other hand, since the amount of the medium flowing into the medium storage container in a high temperature state is small compared to the volume of the medium storage container, the increase in the internal pressure of the medium storage container can be suppressed to a low level.

(Example) An embodiment of the present invention will be described with reference to FIG.

In this embodiment, a steam relief pipe 13 is provided that branches off from a path that leads the steam generated by the evaporator 2 to the turbine 5, and a steam relief valve 14 is installed in the middle of the pipe. The steam relief valve 14 is completely closed during normal operation, and is designed to be opened in the event of a complete power outage in the plant. The other end 15 of the vapor relief pipe 13 is connected to the bottom of the tank 10, and is opened into the tank 10 through a large number of small holes, so that the medium vapor becomes fine bubbles and is ejected into the medium liquid. It is supposed to be done.

In the plant configured as described above, when a power outage occurs throughout the plant, when the occurrence of this condition is detected and the steam relief valve 14 is opened, the medium vapor in the evaporator 2 passes through the steam relief pipe 13. Since the water passes through the tank 10 and escapes to the tank 10, an abnormal increase in pressure inside the evaporator 2 can be prevented. On the other hand, the medium vapor from the evaporator 2 flows into the tank 10, but the medium vapor turns into fine bubbles and ejects into the medium liquid, so the medium liquid at a low temperature absorbs heat and condenses. As a result tank 1
Although the temperature inside the tank 10 and the corresponding pressure inside the tank 10 will increase, if the inflow of medium vapor from the evaporator 2 is treated within a short time, the increase in the pressure inside the tank 10 will not be a problem. Stay in value.

- As an example, at the time of a total power outage in the plant, the average temperature of the hot water existing in the evaporator 2 is 150°C, and the amount held is 6 tons.
The ons medium is R123 (CHCl), which is a type of fluorocarbon.
The temperature of 2F3) is 120℃, the amount held is 15 tons,
Assuming that both systems are sealed, the temperature will drop at about 138℃ and become young, and as a result, the pressure of R123 will change from about 12kg/cd abs to about 17kg/cd abs.
It rises to cJ abs. Such a high temperature is R1
23, and it is desirable to keep the internal pressure of the evaporator 2 as low as possible.

When the present invention is applied to the above embodiment, assuming that the saturated steam of R123 flows from the evaporator 2 to the steam relief pipe 13 at a temperature of 125°C, approximately 4.6 tons of R123
When the hot water is evaporated, the temperature of the hot water from which heat has been removed due to the latent heat of vaporization becomes 125°C, and the temperature of R123 in the evaporator 2 does not rise above 125°C. The saturation pressure at this time remains at about 13 kg/cjabS. Evaporated approx.
6 tons of R123 flows into the tank 10 through the steam relief pipe 13, but in a plant of this scale, the total volume of the tank 10 is about 180 m3, and about 20 tons of R123 is normally stored in it as a reserve. There is. Assuming that the temperature inside the tank 10 is 20°C, if 4.8 tons of R123 saturated steam flows in at 125°C, the inside of the tank 10 will be in equilibrium at a saturated state of temperature 52°C and pressure 2.3 kg/cjabs. .

An accident that causes a power outage to the entire plant is an extremely abnormal accident for a plant, and in such a case, operators will take immediate action, such as starting up an auxiliary power source and discharging hot water. In reality, the situation is on the safer side than in the above calculation example.

As described above, according to this embodiment, the problems of the prior art can be solved without increasing the temperature and pressure of the medium in the evaporator 2 to a low level, and without increasing the withstand pressure of the tank 10 to a very large value. becomes possible.

In the above-described embodiment, the steam relief valves 1 and 4 are opened under the condition that the plant is completely shut down, but the steam relief valves 14 are
It is also possible to use a means such as a spring-loaded safety valve that opens under the condition that the vapor pressure in the medium vapor pipe, that is, the vapor pressure in the evaporator 2 is equal to or higher than a set value.

Further, the steam relief pipe 13 is partially configured with a heat radiating device 16 or is made into a finned pipe to lower the temperature of the medium vapor flowing into the tank 10.
It is conceivable to reduce the pressure rise of 0.

[Effects of the Invention] As explained above, according to the present invention, in a thermal cycle power plant using an organic medium as an operating medium, the steam pipe communicating with the medium vapor generation section and the liquid phase of the medium storage container Because this piping system is equipped with a piping system that connects the side and a valve that opens in the event of a plant abnormality, it is possible to prevent the medium temperature from rising abnormally even when the plant is completely shut down. Eliminates the problem of disassembly. In addition, the pressure increase in the media system can be kept to a small level compared to normal times, and the withstand pressure of related equipment can be lowered, resulting in improved economic efficiency with fewer increases in equipment, transportation costs, and construction costs.

[Brief explanation of drawings]

FIG. 1 is a basic system diagram showing an example of a power plant using an organic medium using the present invention, and FIG. 2 is a basic system diagram of a conventional technology. 2...Evaporator 5...Turbine 7...Condenser 10...Tank 13... ...Steam relief pipe 14 ...Steam relief valve 16 ... Heat dissipation device

Claims (1)

[Claims] In a thermal cycle power plant that uses an organic medium as the power medium, there is a piping system that connects the steam pipe that communicates with the medium vapor generation part and the liquid phase side of the medium storage container, and a A power plant using an organic medium, characterized in that it is provided with a valve that opens.