JPH1026009A - Non-azeotropic mixture medium recycle generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system to improve an output when a heat source temperature and a heat source amount are specified, in a non-azeotropic medium cycle generating system wherein a non-azeotropic medium consisting of low and high boiling point media is utilized as a working medium. SOLUTION: This non-azeotropic medium cycle generating system comprises a vaporizer 1 to vaporize a part of a non-azeotropic medium and bring it into a gas liquid two-phase state; a first gas liquid separator 8 to separate a medium in a gas liquid two-phase state into gas and liquid; first and second condenser 4a and 4b to condense exhaust gas from a turbine 3, to which a gas phase medium separated by the first gas liquid separator is fed, and effect reflex of it to the vaporizer; and an absorption circulation system 10 to take out a part of a working medium flowing out from the condenser 4a and heat and separate it into gas and liquid and thereafter, bring a liquid phase medium into contact and mixture with exhaust gas from the turbine by the condenser. A liquid phase medium 8 separated by the first gas liquid separator is joined with a liquid phase medium in an absorption circulation system after separation of gas from liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-azeotropic mixed medium cycle power generation system using a non-azeotropic mixed medium consisting of a low-boiling medium and a high-boiling medium as a working medium.

[0002]

2. Description of the Related Art Conventionally, in a power generation system using a heat source at a relatively low temperature, a non-azeotropic mixed medium composed of a low-boiling medium and a high-boiling medium is used as a working medium.

That is, FIG. 3 shows that ammonia is used as a low-boiling-point medium component, water is used as a high-boiling-point medium, and a temperature of 150.degree.
FIG. 1 is a system diagram of a non-azeotropic mixed-medium cycle power generation system using a heat source of not more than 1 ° C., wherein a medium comprising ammonia and water is supplied to a generator 1, where the medium is heated and partially evaporated, Is separated into a dense gas phase and a lean liquid phase.

[0004] The gas phase medium separated by the separator 2 is guided to a turbine 3, where it is worked, and then introduced into a condenser 4.

On the other hand, the liquid-phase medium separated by the separator 2 emits heat in the regenerator, is decompressed by the decompressor 6, and is guided to the condenser 4. In the condenser 4, the medium after performing the work in the turbine 3 and the medium depressurized by the decompressor 6 are mixed in contact. Then, the mixed medium returns to the concentration before the evaporation, is cooled and condensed by the condenser 4, and is then cooled by the medium circulation pump 7.
, And is heated by the liquid phase medium separated by the separator 2 and then returned to the evaporator 1.

FIG. 4 is a system diagram showing another example of a conventional power generation system using a non-azeotropic mixed medium, in which a mixed medium of ammonia and water is heated by heat exchange with a heat source in an evaporator 1. Then, it is partially evaporated, and the first separator 8 separates a gas phase in which ammonia is rich and a liquid phase in which ammonia is diluted.

[0007] The gas phase medium separated by the first separator 8 is introduced into the turbine 3, where it performs work, and is then condensed by the first condensate 4a.

On the other hand, the liquid phase medium releases heat in the regenerator 5 and is decompressed by the decompressor 6 to a pressure between the outlet pressure and the inlet pressure of the turbine 3 and then is introduced into the second condenser 4b. Is done.
In the second condenser 4b, the liquid-phase medium depressurized by the decompressor 6 is merged with a part of the medium pressurized by the absorption circulation pump 9 through the first condenser 4a and a cooling source , And pressurized by the medium circulation pump 7,
After being preheated in the evaporator 1.

An absorption circulation system 10 is connected upstream and downstream of the absorption circulation system pump 9. That is, the medium pressurized to the pressure 3 by the absorption circulation pump 9 is divided into the second condenser 4b side and the absorption circulation system 10 side, and the medium divided into the absorption circulation system 10 is Evaporator 1
Is heated in the second evaporator 11 by the heat source used in the above, and then gas-liquid separated in the second separator 12.

[0010] The gas phase medium after gas-liquid separation in the second separator 12 is led to a second condenser 4b, where it is mixed with the medium sent by the absorption circulating system pump 9 and cooled. Condensed by heat exchange with source. The liquid-phase medium separated by the second separator 12 is depressurized by the pressure reducer 13 to the pressure at the outlet of the turbine, and then mixed with the exhaust gas of the turbine.

[0011]

By the way, in the system shown in FIG. 3, the heat exchange close to the Lorentz cycle along the heat source temperature change is caused by the non-isothermal evaporation characteristic of the non-azeotropic mixed medium in the evaporator. It is possible, and a cycle with high exergy efficiency can be realized.

FIG. 5 shows a temperature of 98 ° C. using ammonia / water as a medium.
FIG. 4 is a diagram showing a part of the heat balance of the conventional method cycle when the heat source is used. At the point A in the condenser 4 in FIG. 5, since the ammonia concentration after mixing is 0.9 (mol / mol), the condensation is performed at a high pressure of 828 kPa, and the medium performance can be fully exhibited. There are problems such as not.

When the medium is mixed in the condenser 4, the medium vapor at the point B which is the exhaust port of the turbine 3 and the medium absorbing liquid at the point C of the liquid medium separated by the separator 2 are completely mixed. In order to mix to a uniform concentration of the medium condensate,
On the heat exchange surface of the condenser 4 with the cooling source, an absorbing liquid having a lower ammonia concentration than the medium vapor becomes a liquid film, and the liquid film continuously communicates with the cooling source so that the vapor having a higher ammonia concentration is absorbed by the liquid film. Heat exchange must take place.

However, in the heat balance shown in FIG. 5, the flow rate of the turbine exhaust steam at the point B is 20.5 kg / s.
ec, the flow rate of the absorbent at point C is 5.0K
g / sec, and the flow rate of the absorbing liquid is relatively low as compared with the amount of exhaust steam, so that it is difficult to form an absorbing liquid film having a low ammonia concentration on the heat transfer surface with the cooling source. There is a risk that sufficient mixing and liquefaction may not be performed in the liquid container. If complete condensation is not performed in the condenser, dense ammonia vapor remains in the condenser and the turbine exhaust pressure rises, making it difficult to achieve the heat balance shown in FIG. In some cases.

According to the system shown in FIG. 4, the same heat source temperature of 98 ° C. and the heat source flow rate of 1000 t / h as those in FIG. 3 show that, as shown in FIG. 6, compared with the cycle shown in FIG. Due to the decrease in the ammonia concentration due to the contact mixing between the circulation system and the turbine exhaust, the turbine exhaust pressure at the point B is reduced to 808 kPa, and the turbine work becomes 3044 KW, which increases by about 50 KW. Further, since the flow rate of the absorbent at point D, which flows into the first condenser 4a, is equal to or more than the flow rate of the turbine exhaust, the absorption liquid film having a low ammonia concentration is not formed on the heat transfer surface with the cooling source. This facilitates complete condensation of the turbine exhaust in the condenser.

However, since the concentration created by the absorption circulation system is 0.84 and the concentration difference between the turbine exhaust and the turbine exhaust gas is small, the mass flow of ammonia causes the absorption liquid flow rate to be three times or more the turbine exhaust flow rate. There is a problem that the amount of heat input in the second heat exchanger 11 is increased to 23774 KW, which causes an increase in equipment cost.

In view of the foregoing, an object of the present invention is to provide a system capable of improving the output as compared with the conventional system when the heat source temperature and the heat source amount are specified.

[0018]

In a non-azeotropic mixed-medium cycle power generation system using a non-azeotropic mixed medium consisting of a low-boiling medium and a high-boiling medium as a working medium, heat exchange with a relatively low-temperature heat source is performed. An evaporator for evaporating a part of the non-azeotropic mixed medium into a gas-liquid two-phase state, a first gas-liquid separator for separating the medium in the gas-liquid two-phase state, and a first gas-liquid separator; A turbine supplied with a gas phase medium separated by the liquid separator,
First and second condensers for condensing the exhaust gas from the turbine and returning to the evaporator, and taking out a part of the working medium flowing out of the first condenser, heating and gas-liquid separation ,
An absorption circulation system for bringing the liquid phase medium into contact with the exhaust gas from the turbine in the first condenser, and mixing the liquid phase medium separated by the first gas-liquid separator with the gas-liquid of the absorption circulation system. It is characterized by being joined to the liquid phase medium after separation.

[0019]

Embodiments of the present invention will be described below with reference to FIG. In the figure, the same parts as those in FIG. 4 are denoted by the same reference numerals.

The mixed medium of ammonia and water is heated in the evaporator 1 by heat exchange with a relatively low-temperature heat source of about 150 ° C. or less, such as geothermal heat, solar hot water, or plant exhaust heat, and partially evaporates. In the first separator 8, the ammonia-rich gas phase and the ammonia-rich liquid phase are separated. Then, the gas phase medium separated by the first separator 8 is introduced into the turbine 3, where the work is performed, and then the liquid is condensed by the first condenser 4 a and the second condenser 4 b. Thereafter, the pressure is increased by the medium circulation pump 7 and returned to the evaporator 1 via the regenerator 5.

The first condenser 4a and the second condenser 4b
An absorption circulation pump 9 is provided between the first and second condensers 4a, and an absorption circulation system 10 connects the downstream side of the absorption circulation pump 9 and the working medium flow pipe of the first condenser 4a. . The absorption circulation system 10 is provided with a second evaporator 11, a second separator 12, and a pressure reducer 13 to which a heat source used in the evaporator 1 is supplied.

On the other hand, the liquid phase portion of the first separator 8 is connected to the conduit 1
4 is connected via a regenerator 5 and a decompressor 6 to the downstream side of the decompressor 13 of the absorption circulation system 10, and the gas phase of the second separator 12 is connected via a conduit 15 to a second It is connected to the working medium flow pipe of the condenser 4b.

The exhaust gas which has performed the work in the turbine 3 is condensed in the first condensate 4a,
After the pressure is increased in the second condenser 4b, the liquid is further condensed,
It is returned to the evaporator 1 side by the medium circulation pump 7.

A part of the working medium pressurized by the absorption circulation pump 9 is diverted to the absorption circulation system 10 and exchanges heat with the heat source used in the evaporator 1 in the second evaporator 11. Is heated and introduced into the second separator 12, where it is separated into gas and liquid. Then, the liquid phase medium separated by the second separator 12 passes through the decompressor 13 and is contact-mixed with the turbine exhaust in the first condenser 4a.

The gas-phase medium separated by the second separator 12 is mixed with the working medium by the second condenser 4b.

Incidentally, the liquid phase medium separated into gas and liquid by the first separator 8 exchanges heat with the working medium flowing into the evaporator 1 by the regenerator 5 and then is depressurized by the decompressor 6 to be decompressed by the absorption circulation system. 1
The liquid phase medium separated by the second separator 12 is merged downstream of the zero pressure reducer 13 and introduced into the first condenser 4a.

FIG. 2 is a block diagram of the system shown in FIG.
Heat source temperature 98 ° C and heat source flow rate 100
FIG. 5 is a diagram showing an example of a heat balance at 0 t / h, similar to the cycle shown in FIG. 4. Exhaust pressure is 82
From 8 kPa to 808 kPa, the turbine work increases by about 50 KW.

Since the amount of the liquid phase medium mixed in the first condenser 4a is equal to the amount of exhaust gas from the turbine, the heat transfer surface of the first condenser 4a has an intake liquid film having a low ammonia concentration on the heat transfer surface. Is easily formed, and the turbine exhaust is easily condensed in the condenser. In addition, since the concentration difference between the ammonia concentration of the liquid phase medium formed in the absorption circulation system and the turbine exhaust is 0.777, which is larger than that of the conventional system, the mass flow of the ammonia causes the absorption liquid flow rate to be greater than the turbine exhaust flow rate. The heat input from the heat source in the second steamer 11 is also 6786 KW, which can be reduced as compared with the conventional system, and the increase in equipment cost can be minimized.

Further, in the liquid system of the absorption circulation system including the second separator 12, an additive for facilitating substance diffusion by interfacial disturbance at the liquid film interface, for example, n-type in the case of a water / lithium bromide mixed medium. By injecting and circulating octanol or the like, contact mixing with turbine exhaust can be facilitated and cycle efficiency can be improved.

Further, a medium having an effect of increasing the boiling point, for example, a salt, is introduced into the circulation system of the liquid phase medium including the evaporator 1, the first separator 8, the regenerator 5, and the like to reduce the pressure at the time of evaporation of the medium. The output can be further improved by increasing the work amount in the turbine to increase the work amount, and by using the medium having the boiling point increasing effect in an area where evaporation does not occur.

In the above embodiment, the medium is composed of two components of water and ammonia. However, the medium may be composed of three components such as water, ammonia and lithium bromide. 90 ° C ~
An ammonia concentration of 0.7 to 0.95 mol / mol with a heat source of about 200 ° C. is preferred.

[0032]

As described above, according to the present invention, the liquid-phase medium separated by the first gas-liquid separator is combined with the liquid-phase medium after gas-liquid separation in the absorption circulation system, and is combined with the turbine exhaust gas. Because of the contact mixing, not only can the turbine exhaust pressure be lowered to increase the turbine work load, but also it becomes easier to form an absorbing liquid film having a low ammonia concentration on the heat transfer surface with the cooling source in the condenser. And the like can be completely condensed.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of a non-azeotropic mixed medium cycle power generation system of the present invention.

FIG. 2 is a diagram showing an example of a heat balance of the system shown in FIG. 1;

FIG. 3 is a system diagram showing an example of a conventional non-azeotropic mixed medium cycle power generation system.

FIG. 4 is a system diagram showing another example of a conventional non-azeotropic mixed medium cycle power generation system.

FIG. 5 is a diagram showing an example of a heat balance of the system shown in FIG. 3;

FIG. 6 is a view showing an example of a heat balance of the system shown in FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 evaporator 2 separator 3 turbine 4 condenser 4a first condenser 4b second condenser 5 regenerator 7 medium circulation pump 8 first separator 9 absorption circulation pump 10 absorption circulation 11 2 evaporator 12 2nd separator 13 decompressor

Claims (7)

[Claims] In a non-azeotropic mixed medium cycle power generation system using a non-azeotropic mixed medium consisting of a low-boiling medium and a high-boiling medium as a working medium, the non-azeotropic mixing is performed by heat exchange with a relatively low-temperature heat source. An evaporator that evaporates a part of the medium into a gas-liquid two-phase state, a first gas-liquid separator that separates the medium in the gas-liquid two-phase state, and a first gas-liquid separator A turbine to which the separated gas phase medium is supplied, first and second condensers for condensing exhaust gas from the turbine and returning the exhaust gas to the evaporator, and a working medium flowing out of the first condenser Having a circulating system for taking out a part of the mixture, heating and gas-liquid separation, and then contacting and mixing the liquid phase medium with exhaust gas from the turbine in the first condenser. The separated liquid phase medium is combined with the liquid phase medium after gas-liquid separation in the absorption circulation system. Wherein the non-azeotropic mixed medium cycle power generation system. 2. The non-azeotropic mixed medium cycle power generation system according to claim 1, wherein the gas phase medium separated in the absorption circulation system is contact-mixed with the working medium in the second condenser. 3. The non-azeotropic mixed-medium cycle power generation system according to claim 1, wherein the relatively low-temperature heat source is a heat source of 150 ° C. or lower. 4. The non-azeotropic mixed medium cycle power generation system according to claim 1, wherein the heat source is geothermal heat, solar hot water, or plant exhaust heat. 5. The working medium of the absorption circulation system further comprises an additive for uniformly mixing a low-boiling-point medium-dilute solution and turbine exhaust gas.
A non-azeotropic mixed-medium cycle power generation system according to any one of the above. 6. A working medium at the inlet of the evaporator is supplied with a medium having a boiling point increasing effect in order to increase exergy efficiency and increase work in a turbine by increasing the temperature during medium evaporation. The non-azeotropic mixed medium cycle power generation system according to claim 1. 7. The working medium is an ammonia / water mixed medium,
When a heat source of about 0 ° C to 200 ° C is used, 0.7
The non-azeotropic mixed-medium cycle power generation system according to any one of claims 1 to 6, wherein a concentration ratio of the ammonia concentration is from 0.95 mol / mol to 0.95 mol / mol.