JPH0791213A - Binary power generation system - Google Patents

Abstract

PURPOSE:To reduce absorbing pressure and condensation pressure to increase power generation output in a binary power generation system, for which a heat cycle is formed with a non-azeotropic mixture serving as a working medium, and which is provided with an absorber for absorbing the steam not yet condensed on the outlet of a condenser. CONSTITUTION:When a liquid high in the concentration of high boiling point component, for which a low boiling point component in a working medium is separated by an evaporator 2, is used as an absorbing liquid in an absorber 16, after an absorbing liquid is heat-exchanged with a condensed liquid by a preheater 18, the temperature of the absorbing liquid is further lowered by another cooling heat source by a cooler 20 to feed the absorbing liquid to the absorber 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binary power generation system in which a non-azeotropic mixture is used as a working medium to form a heat cycle.

[0002]

2. Description of the Related Art In binary power generation using a non-azeotropic mixture as a working medium, the concentration of low-boiling components increases at the outlet of a condenser, which hinders heat transfer and mass transfer. An absorber is installed to eliminate this high-concentration low-boiling-point component vapor, and the absorption liquid absorbs the low-boiling-point component vapor by using the evaporation residual liquid introduced from the working medium outlet of the evaporator as the absorption liquid. There is. In the evaporator, the low-boiling point component is likely to evaporate preferentially, so the concentration of the low-boiling point component in the evaporation residual liquid at the working medium outlet of the evaporator is low. Therefore, this evaporation residual liquid easily absorbs the low boiling point component vapor.

Conventionally, an absorbing liquid is used for preheating the condensate for the purpose of heat recovery, that is, in order to prevent a decrease in system efficiency (JP-A-5-59907).

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a binary power generation system in which a heat cycle is constituted by using a non-azeotropic mixture as a working medium, and an absorber for absorbing uncondensed vapor at a condenser outlet is provided. Among them, the absorption pressure and the condensation pressure are lowered to increase the power generation output.

[0005]

According to the present invention, when a liquid having a high concentration of high-boiling components separated from low-boiling components of a working medium by an evaporator is used as an absorption liquid by an absorber, the absorption liquid becomes a condensate. After heat exchange, the temperature of the absorbing solution was lowered by another cooling heat source and sent to the absorber.

[0006]

[Function] By further lowering the temperature of the absorbing liquid, which has been lowered by heat exchange with the condensing liquid, by the cooler, the temperature of the absorber is lowered, and the absorption pressure and the condensing pressure are lowered. When the condensing pressure decreases, the pressure ratio (evaporating pressure / condensing pressure) in the turbine increases, and the power generation output increases.

Referring to the vapor-liquid equilibrium diagram of FIG. 2,
The solid gas and liquid lines represent the state of the working medium under conventional pressure, while the dotted gas and liquid lines represent the reduced pressure state. Shows. In this way, by cooling the absorbent,
Even if the concentration is the same, the outlet temperature of the absorber is lowered and the pressure of the absorber and the pressure of the condenser are lowered.

[0008]

EXAMPLE As shown in FIG. 1, a binary power generation system includes an evaporator (2), a gas-liquid separator (14), a turbine (4), a condenser (6) and a circulation pump (8) connected in series. To form a closed loop (10).
The working medium circulates in 0).

First, in the evaporator (2), the working medium in the liquid phase takes heat from the heat source fluid and evaporates, and the generated vapor advances to the gas-liquid separator (14) with the unvaporized liquid. Gas-liquid separator (1
The steam and liquid are separated in 4), and the steam is supplied to the turbine (4). The steam is expanded by the turbine (4) and the generator (1
2) Do the job of driving. The steam discharged from the turbine (4) is sent to the condenser (6) where it is deprived of heat by the cooling water and condensed. The condensate is returned to the evaporator (2) by the working medium circulation pump (8) via the gas-liquid separator (15). The vapor that has not condensed in the condenser (6) is guided from the gas phase portion of the gas-liquid separator (14) to the absorber (16).

On the other hand, the liquid separated from the vapor in the gas-liquid separator (14) is led to the absorber (16) through the preheater (18) and the cooler (20), and is used as an absorbing liquid. It The liquid leaving the absorber (16) merges with the liquid from the condenser (6),
It is returned to the evaporator (2) again by the working medium circulation pump (8). At this time, the condensate of the liquid is preheated by the preheater (18) before the evaporator (2).

As described above, in the absorber (16), the liquid introduced from the working medium outlet of the evaporator (2) is used as the absorbing liquid, and the uncondensed vapor from the condenser (6) is fed into the absorbing liquid. Be done. This absorbing liquid has a low low-boiling point concentration because the low-boiling point component is likely to evaporate preferentially in the evaporator (2), and easily absorbs vapor with a high low-boiling point concentration. Furthermore, since the temperature of this absorbing liquid is lowered by passing through the preheater (18) and further cooled by the cooler (20), the temperature of the absorber (16) is lowered, and the absorption pressure and the condensation are reduced. The pressure drops.

FIG. 2 is a vapor-liquid equilibrium diagram showing the state of the working medium under a constant pressure. The state represented by the solid vapor line and the liquid line is different from the dotted vapor line and The state represented by the liquidus line represents the state in which the pressure is lowered. That is, in the state under the conventional pressure represented by the solid line, the absorption liquid increases the low boiling point component concentration as it absorbs the low boiling point component vapor, and transitions from point a to point b.
By cooling the absorption liquid, the point a'is changed to the point b '. Therefore, even if the concentration of the absorbing liquid is the same as the conventional one, the pressure drops to the state shown by the dotted line. Since the power generation output is proportional to the pressure ratio (evaporation pressure / condensation pressure) in the turbine, the power generation output increases as the condensation pressure decreases.

[0013]

As described above, the present invention is a binary power generation system in which a thermal cycle is formed using a non-azeotropic mixture as a working medium, and an absorber for absorbing uncondensed vapor at the condenser outlet is provided. When using a liquid having a high concentration of high-boiling components separated from the low-boiling components of the working medium by the evaporator as an absorbing liquid in the absorber, after the heat exchange of the absorbing liquid with the condensate, another Since the temperature of the absorbing liquid is lowered by the cooling heat source and sent to the absorber,
By lowering the temperature of the absorbing liquid, the temperature of the absorber is lowered, and the absorption pressure and the condensing pressure are lowered. Therefore,
The output of the binary power generation system increases as the condensing pressure decreases.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an example.

FIG. 2 Gas-liquid equilibrium diagram of working medium

[Explanation of symbols]

 2 Evaporator 4 Turbine 6 Condenser 8 Working medium circulation pump 10 Closed loop 12 Generator 14 Gas-liquid separator 16 Absorber 18 Preheater 20 Cooler

Claims (1)

[Claims] 1. A binary power generation system in which a heat cycle is constituted by using a non-azeotropic mixture as a working medium, the binary power generation system having an absorber for absorbing uncondensed vapor at the outlet of the condenser, and the working medium in the evaporator. When using a liquid with a high concentration of high-boiling components separated from the low-boiling components of as an absorption liquid in the absorber, after the heat exchange of the absorption liquid with the condensate, lower the temperature of the absorption liquid with another cooling heat source. A binary power generation system characterized by sending to an absorber.