JP2513937B2 - Non-azeotrope condenser - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to condensers for non-azeotropes used as working fluids in low boiling medium systems such as heat pumps and binary cycles.

[0002]

2. Description of the Related Art A binary power generation system shown in FIG. 4 will be described as an example of a low boiling point medium system. An evaporator 2, a turbine 4, a condenser 6 and a medium pump 8 are connected in series to form a closed loop 10. There is. The working fluid circulating in the closed loop 10 first evaporates by removing heat from the heat source fluid in the evaporator 2, and the generated steam is supplied to the turbine 4. This steam expands in the turbine 4 and serves to drive the generator 12. The steam discharged from the turbine 4 is deprived of heat by the cooling water in the condenser 6 and condensed.
The condensate is sent to the evaporator 2 again by the circulation pump 8.

By the way, in such a heat cycle such as a binary cycle or a heat pump, a Lorentz cycle may be constituted by using a non-azeotropic mixed medium as a working fluid in order to improve efficiency. For example, a binary cycle is basically a Rankine cycle. When the working fluid is a single medium, as shown in FIG.
-Indicates isothermal changes. However, Freon R
When a mixed medium such as a mixture of 123 and R22 is used as the working fluid, as shown in FIG. 6, the saturation temperature changes even at the same pressure, and the evaporation temperature increases in the evaporator 2 and the condensation temperature decreases in the condenser 6. . This forms a Lorentz cycle and improves system efficiency.

FIG. 7 shows the relationship between the temperature and the composition of the simplest two-component liquid-vapor system in terms of the mole fraction of low-boiling components on the horizontal axis. G and L are single phases, respectively, a gas phase and a liquid phase, and a region of L + G is a two-phase region where a liquid and a vapor coexist. If the temperature of a liquid mixture of 60 mol% (mol fraction = 0.60) of the low boilers is increased under constant pressure, the change in this system can be considered along a straight line ab'cd "e.
At low temperatures, only a liquid phase exists, but a vapor phase appears at point b '. The composition of this vapor phase is given by the point b ", and the two conjugate phases are connected by an equilibrium connection line b" b 'in the figure. Increasing the temperature will produce more steam, in which case
Due to the high concentration of low boiling components in the vapor, this component is relatively reduced in the liquid phase, the composition of the liquid changes along b'c'd ', while the composition of the vapor is b "c" It changes along the d ". At the temperature t ° C, the total composition of the system in the two-phase region is represented by the point c, but the vapor composition and the liquid composition are both ends of the equilibrium connecting line passing through the point c," Given by points and c'points. The relative amounts of the two phases are determined from the principle of leverage in physics. That is, the ratio of the number of moles of vapor to liquid is represented by the ratio of the length of cc 'to c "c. As the temperature is further increased, more and more vapor is generated, and d"
At the point, the liquid phase almost disappears, and when the temperature becomes higher than this, the liquid phase disappears and only the vapor phase (d "point) remains. Even if the temperature is further raised (along d" e) Does not happen.

[0005]

In the conventional condenser for non-azeotropic mixture, the high-boiling component is condensed at the inlet portion, and the low-boiling component is condensed in a phase equilibrium balance.

An object of the present invention is to promote the condensation of low boiling components over the entire heat transfer surface of the condenser to improve the condensation heat transfer performance of the condenser for non-azeotropic mixture.

[0007]

The present invention relates to a condenser for a non-azeotropic mixture composed of two or more fluids having different boiling points, in which a liquid having a low low boiling point component concentration is injected from an upper inlet portion. Thus, a liquid film having a low low boiling point component concentration is formed on the entire vertical heat transfer surface.

[0008]

As shown in FIG. 1, a liquid 22 having a low low boiling point component concentration, in other words, a high boiling point component concentration is injected from the inlet of the condenser to spread the low boiling point component on the entire condensation heat transfer surface 20 of the condenser. By forming the film of the liquid 22 having a low concentration, the opportunity for the low boiling component gas 24 to come into contact with the liquid 22 having a low low boiling component concentration is sufficiently secured, so that the condensation of the low boiling component gas 24 is promoted. Further, in this way, the low boiling component concentration is Xc on all the heat transfer surfaces 20.
To X ', the low-boiling components are further condensed.

In the Lorentz cycle, the evaporation residual liquid at the outlet of the evaporator can be used as the liquid 22 having less low boiling point components.

[0010]

EXAMPLE A case of application to the above-mentioned binary power generation system shown in FIG. 4 will be described as an example. As shown in FIG. 2, a mist separator 14 is installed on the outlet side of the evaporator 2 and the lower outlet thereof is evaporated. Connect to the inlet side of the vessel 2. An aftercooler 16 for separating the low boiling point component gas is installed on the outlet side of the condenser 6. The after cooler 16 is also a kind of condenser in that it has a function of further cooling and condensing the uncondensed gas at the outlet of the condenser 6. A pipe 18 connects the lower outlet of the mist separator 14 and the inlet of the aftercooler 16.

The working fluid discharged from the evaporator 2 is separated by a mist separator 14 into vapor and evaporation residual liquid. The steam is supplied to the turbine 4 for work, and then the condenser 6 removes heat from the cooling water to condense it. The evaporation residual liquid separated from the steam by the mist separator 14 is sent from the lower outlet through the pipe 18 to the aftercooler 16, and is injected from the inlet to the heat transfer surface.

The low-boiling component concentrations of the evaporator 2 and the condenser 6 in this case are as shown in FIG. As you can see from Figure 3,
Evaporation residual liquid at the outlet of the evaporator has the lowest low boiling point concentration X in the system.
e. On the other hand, at the outlet of the condenser 6, the concentration of the low boiling point component gas in the state indicated by Xc is very high. Therefore, it is injected from the inlet of the aftercooler 18 and condensed on the heat transfer surface 20.
The low-boiling component gas 24 is absorbed by the evaporation residual liquid 22 having a low low-boiling component concentration, which has formed a liquid film on the inside (see FIG. 1).

In the above-mentioned embodiment, the aftercooler 16 installed at the outlet of the condenser 6 is regarded as a second-stage condenser when the condenser 6 is the first stage. It is also possible to form a film of a liquid having a low low boiling point component concentration. However, in that case, although the same action and effect can be expected from the viewpoint of promoting the condensation of the low boiling point component, the contact between the gas to be condensed and the heat transfer surface is cut off by forming a liquid film on the condensation heat transfer surface. It should be noted that this is also the case.

[0014]

As described above, according to the present invention, a liquid having a low low boiling point component concentration is jetted from the inlet to form a liquid film having a low low boiling point component concentration over the entire heat transfer surface. Therefore, a liquid film having a low low boiling point component concentration is formed on the entire condensation heat transfer surface of the condenser. Therefore, the opportunity of contacting the low-boiling component gas with the liquid having a low low-boiling component concentration is sufficiently ensured, and the condensation of the low-boiling component is promoted. Further, in this way, the concentration of the low-boiling component is lowered on all the heat transfer surfaces, so that the condensation of the low-boiling component further proceeds. According to the present invention, the heat transfer performance of the condenser for non-azeotropic mixture can be improved in this manner.

[Brief description of drawings]

FIG. 1 is a sectional view (A) of a main part of a condenser schematically showing the operation of the present invention and a corresponding concentration diagram.

FIG. 2 is a flow sheet of a binary power generation system showing an embodiment of the present invention.

3 is a vapor-liquid equilibrium diagram of a working fluid in the binary power generation system of FIG.

FIG. 4 is a flow sheet of a binary power generation system.

FIG. 5 is a TS diagram of a Rankine cycle.

FIG. 6 is a TS diagram of a Lorentz cycle.

FIG. 7 is a vapor-liquid equilibrium diagram showing a temperature-composition relationship of a non-azeotropic mixture.

[Explanation of symbols]

 2 Evaporator 4 Turbine 6 Condenser 8 Circulation pump 12 Generator 14 Mist separator 16 After cooler 18 Piping 20 Condensation heat transfer surface 22 Liquid with low boiling point component concentration 24 Low boiling point component gas

Continuation of the front page (56) References JP-A-58-67975 (JP, A) JP-B-61-9482 (JP, B2)

Claims (1)

(57) [Claims] 1. A condenser for a non-azeotropic mixture composed of two or more fluids having different boiling points, wherein a liquid having a low concentration of low boiling components is injected from an upper inlet portion to cover the entire vertical heat transfer surface. A condenser for a non-azeotropic mixture, which is adapted to form a liquid film having a low concentration of low-boiling components.