JPS5827806A - Binary fluid power generating device - Google Patents

Abstract

PURPOSE:To improve the heat recovery efficiency by using a mixture prepared by mixing a plurality of heat mediums having different boiling points as a low boiling point medium. CONSTITUTION:By using a mixture prepared by mixing a plurality of heat mediums RA (low boiling point) and RB (high boiling point) as an operating medium of a low boiling point to drive a binary fluid power generating device. The operating medium enters into an evaporator (not shown) at a temperature t1. When the temperature reaches a value indicated by tva, the heat medium RA starts vaporization. At a point x3 in time where the evaporation is completed, the temperature resumes to rise up. When the temperature reaches a value indicated by tvb, the heat medium RB starts evaporation, and is maintained at the temperature tvb until the completion point x5 in time. Accordingly, the heat medium RA evaporates at the temperature tva between points in time x2 and x3, and the heat medium RB at the temperature tvb between points x4 and x5 in time. By this procedure, it is possible to obtain the quantity of evaporation equivalent to the case of using a heat medium having smaller evaporation latent heat, and also to take out a larger electric output from a given heat source.

Description

[Detailed Description of the Invention] The present invention heats and vaporizes a low-boiling point medium using a medium-low temperature heat source such as geothermal water, various types of waste heat, and warm sea water, and rotates a turbine generator as the medium to generate electricity. The present invention relates to a two-fluid power generation device.

FIG. 1 is a conceptual diagram showing an example of the basic configuration of a two-fluid power generation device, where l is an evaporator, 2 is a turbine generator, 3 is a condenser,
4 indicates a pump, and number 4 indicates a heat source supply pipe. In this two-fluid power generation device, a working medium with a low boiling point is heated in the evaporator 1 by a heat source supplied by a heat source supply pipe, becomes steam, and is introduced into the turbine generator 2 through a coiled pipe 6, where it is fed into a working fluid. Thereafter, it is cooled and condensed in a condenser 3. The working medium cooled and condensed in the condenser 3 is distributed by the pump 4.
The working medium that passes through the evaporator 1 and returns to the evaporator 1 to form a closed cycle is heated in the evaporator 1,
Although the temperature rises and vaporizes, the relationship between the temperature of the heat source and working medium and the amount of heat exchanged during this exit is shown in FIG. The X axis of this figure.

On the y-axis, the amount of heat exchanged (kcaA/H), the temperature (C), and Tt -Tm -Ts are shown, respectively.
'le't indicates the inlet temperature, intermediate temperature, and outlet temperature of the heat body, respectively, and 'le't indicates the inlet temperature and saturation temperature of the working medium, respectively.

That is, in FIG. 2, the fluid on the heat source side is at a temperature T.

On the other hand, the working medium is supplied to the evaporator 1 in liquid form at a temperature t1 and heated until the saturation temperature *t, rc difference is reached. This indicates that the steam starts to evaporate, becomes saturated steam, and is supplied to the turbine generator 2.

The heat exchange in the M generator can be divided into the preheating section and the J generator. In this case, the working medium is heated in the preheating section from temperature It't to t, and the heat source side fluid is heated to temperature f.
The temperature drops from T, to T,t. In the evaporation section, the working medium absorbs heat equivalent to the latent heat of vaporization at the saturation temperature T, and exits as saturated steam, and the heat source side fluid temperature drops from T to T.

Therefore, when designing a power generation device with the configuration shown in Fig. 1 that performs heat exchange as shown in Fig. 2, the input temperature *T, and flow rate Qh of the heat source Iut body are given in advance, and the The surface steam pressure and the type of working medium are selected so that the maximum amount of heat can be absorbed into the working medium and the maximum amount of heat can be converted into electrical energy. However, using only one type of working medium, evaporation starts at its saturation temperature of 1 ittv;
In such a scheme, the evaporator outlet temperature T of the heat source fluid
, did not descend sufficiently and had to be ejected, so the electrical energy that could be extracted was extremely low.

The purpose of the present invention is to provide a 92-fluid power generation device with extremely high vhllih recovery efficiency, in which steam generated by heating and vaporizing a low boiling point heat medium with a medium-low temperature heat source is used as a working medium to generate turbine power generation. A two-fluid power generation device that rotates a machine to generate electricity is characterized by using a mixture of multiple types of heat carriers having different boiling points as a low-boiling heat carrier.

The present invention was obtained as a result of a study on the heat recovery efficiency of a conventional two-fluid power generation device that uses one type of working medium, and the study results will be explained next.

In the case of the conventional two-fluid power generation shown in FIG. 2, the steam pressure (or saturated steam temperature t), the heat source fluid temperature Tt at the starting point of evaporation of the working medium, and the saturation temperature 1. When the temperature difference (generally called the pinch point) ΔT is determined, the evaporation amount Gv of the working medium is determined by the following equation.

GV=G11-(TI-〒t) Ck/Hv
・”(1) However, Gh: Heat source fluid flow rate (Kt/h) Ch: Heat source fluid average specific gravity (kcxt/~・C) HY: Working medium latent heat of evaporation (kca4/!4) When the evaporation amount GV is determined, the amount of heat recovered in the preheating section,
That is, it shows that the heat source fluid temperature &'rs at the evaporator outlet is fixed, and secondly, the latent heat of vaporization H of the working medium
This shows that if a working medium with a small V is used, the amount of evaporation GV increases, the amount of heat recovered in the preheating section decreases, and the electric output that can be extracted also increases.

Based on these study results, the present invention uses a mixture of multiple types of low boiling point media with true boiling points as the working medium, that is, a mixed heat medium that evaporates at several different temperatures. The same effect as using a working medium with a low latent heat of vaporization can be obtained, and the heat retained by the heat source is absorbed to the maximum extent by the working fluid, which is a low-boiling heat medium.
heat recovery), making it possible to provide a two-fluid power generation device with extremely high heat recovery efficiency.

Examples will be described below.

Figure 3 shows an example in which two types of low-boiling heat media with different boiling points (the one with the lower boiling point is called RA and the one with the higher boiling point is called B) are mixed and used as a working medium.
It shows the relationship between the temperature of the heat source fluid and the working medium and the amount of heat exchanged.

On the X and Y axes of this figure,! Similarly to the s2 diagram, the amount of heat exchanged (kcat/H) and the temperature (C) are Tm
, Ti -Ts are the heat f/1tIt, the inlet temperature and the outlet temperature of the body, Tm * T, are the three different intermediate temperatures, 'le'? ally4 respectively sets the inlet temperature of the working medium, the saturation temperature of the heat medium HA, and the saturation temperature of the heat medium RB as ΔT, 1. ΔT2. indicate the pinch points of the heat medium RB and heat medium RA, respectively.

The working medium of this two-fluid power generation device is a mixture of eight low boiling point heat carriers and RB, so it enters the evaporator 1 at a temperature t), and when the temperature is suitable for La, the heat carrier RA becomes Heat medium R
Since the boiling point is lower than that of B, evaporation starts and the temperature rises again from the point when evaporation is completed (point ``s'') until the temperature reaches t, h.
When the temperature reaches , the heat carriers R and B begin to evaporate and are maintained at the temperature vb until the evaporation is completed (sO fish). That is, in FIG. 3, the heating medium for ordinary people is t? between X and x8. , and the heat medium RB evaporates between X and x at a temperature tvb.

In this way, when heat medium RA and heat mediums R and B evaporate at different temperatures, it is possible to obtain the same effect as using a heat medium with a small latent heat of vaporization when using a single heat medium. , α), the electrical output extracted from a given heat source can be increased without increasing the amount of evaporation.

Note that the type of low-boiling heat medium to be mixed and the mixing ratio are selected to provide optimum conditions depending on the characteristics of the heat source and the characteristics of the heat medium.

As described above, the two-fluid power generation device of the present invention makes it possible to provide a two-fluid power generation device with extremely high heat recovery efficiency, and has great industrial effects.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an example of the basic configuration of a two-fluid power generation device, and FIG. 2 is a diagram showing the relationship between the temperature of the heat source and working medium and the amount of heat exchanged in a conventional two-fluid power generation device. #I3 The figure is a diagram showing the relationship between the temperature of the heat source and the working medium and the amount of heat exchanged in an embodiment of the two-fluid power generation device of the present invention. l...Evaporator, 2...Turbine generator, 3...Condenser, (1 other person) Figure 1 Figure 2 Exchanged heat amount (Kcal/H)

Claims (1)

[Claims] 1. A low boiling point heat medium is heated by a medium to low temperature heat source. The vaporized steam is used as a working medium for a turbine generator.
1. A two-fluid power generation device which generates electricity by converting the boiling point of a plurality of types of heat carriers having boiling points as the low-boiling point heat medium.