JPH0449025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a heat recovery device, which can be used to effectively recover heat from relatively low-temperature heat sources such as factory wastewater.

BACKGROUND TECHNOLOGY A heat recovery device is already known that uses a Rankine cycle to recover heat from heated wastewater discharged from a factory and uses the recovered heat for power generation or the like. For example, the device described in JP-A-60-144594 has an evaporator 2 for heating and evaporating a working fluid such as fluorocarbon using waste heat as a heat source, as shown in FIG. A non-displacement expander such as a steam turbine or a positive displacement expander such as a screw expander that is rotationally driven by the high temperature, high pressure working fluid steam generated in 4, a condenser 6 for cooling and condensing the low-pressure working fluid vapor that has finished its work, and a condenser 6 for cooling and condensing the working fluid vapor into the system. The output shaft of the steam engine 4 is connected to a generator or other load 10 depending on the form of use of the recovered thermal energy.

Problems to be Solved by the Invention Conventionally, in order to recover power from a relatively low temperature heat source of around 60℃, when ordinary cooling tower water is used as a cold heat source, the difference between the evaporation temperature and condensation temperature of the working fluid is 13 It was difficult to put it into practical use because the temperature was only about ℃.

This invention aims to provide a heat recovery device that can secure a larger heat drop even with the same heat source, thereby increasing the output or downsizing the steam engine to reduce mechanical loss. be.

Means for Solving the Problems The present invention adds the following elements to the conventional heat recovery device described above: Part of the working fluid is diverted from the outlet side to the inlet side of the evaporator. Bypass for the bypass; A second condenser connected in the middle of the bypass; An ejector provided in the bypass on the upstream side of the second condenser; A downstream part of the second condenser of the bypass and the ejector are connected, and the ejector is connected to A pipe line connected to the cold source side of the vessel; A pressure reducing valve provided in the pipe line between the condenser of the pipe line and the second condenser.

Operation The working fluid vapor generated in the evaporator is branched and supplied to the steam engine and the ejector. The high-temperature, high-pressure working fluid vapor that has advanced to the ejector passes through the ejector at high speed, sucking in the working fluid vapor coming from the first condenser through the conduit, and then passing through the ejector to the second condenser. Proceed through the bypass.

In the second condenser, the working fluid vapor loses heat to the cooling water and condenses. The working fluid is pumped back to the evaporator, but part of it enters the line under the action of the ejector and passes through the pressure reducing valve into the first condenser. The pressure is reduced by the pressure reducing valve, resulting in low temperature and low pressure.

The high-temperature, high-pressure working fluid vapor that has proceeded from the evaporator to the steam engine expands inside the steam engine, thereby applying rotational force to the output shaft. The working fluid vapor, which has reached a low pressure after completing its work, is cooled and condensed in the first condenser by the low-temperature, low-pressure working fluid that comes from the second condenser through the pressure reducing valve. The condensed working fluid is pumped back to the evaporator.

Thus, in the first condenser, the working fluid vapor discharged from the steam engine is cooled to a lower temperature than before, ensuring an increased working fluid heat drop.

Embodiment Next, an embodiment of the present invention shown in FIG. 1 will be described. It should be noted that the numerical values added in the figure are only examples for explanation (in the case of R114).

In the illustrated embodiment, the first and second condensers 16, 17 are located in parallel with each other, and the working fluid vapor from the evaporator 12 is branched to both. That is, a portion passes through the steam engine 14 , the first condenser 16 , and the first pump 18 and returns to the evaporator 12 . This trend remains unchanged.

The other part passes through the bypass 13 to the second condenser 17 and is returned to the evaporator 12 by the second pump 19. However, a part of it is further transferred from the downstream side of the second condenser 17 to the upstream side of the first condenser 1.
6 and circulate. That is, the ejector 21 located on the upstream side of the second condenser 17 causes the working fluid vapor heading from the evaporator 12 to the second condenser 17 to flow through at high speed, and uses this as driving vapor to generate the second condenser. The working fluid is sucked through a pipe line 15 branched from the bypass 13 on the downstream side of the vessel 17. Since the pressure reducing valve 22 is provided in the pipe line 15, the pressure of the working fluid is reduced and then the working fluid is transferred to the first condenser 16.
to go into.

In the second condenser 17, the working fluid vapor loses heat to the cooling water and condenses. The working fluid liquid is sent again to the evaporator 12 by the second pump 19, but a portion of it passes through the pressure reducing valve 22 and enters the first condenser 16, as described above, where it is extracted from the working fluid vapor from the steam engine 14. It absorbs heat, evaporates, and is guided to the ejector 21. The working fluid, which is the source of cold heat in the first condenser 16, has a considerably low pressure and low temperature by passing through the pressure reducing valve 22, so
The working fluid vapor discharged from the pump is cooled to a considerably lower temperature than before.

Effects of the Invention As explained above, according to the present invention, the temperature difference between evaporation and condensation of the working fluid can be increased, so the output can be increased and it is a practical method that can effectively recover heat even from low-temperature heat sources. A heat recovery device can be provided. Alternatively, since the heat drop of the working fluid is large, it is possible to use a smaller steam engine than in the past for the same output scale. This is advantageous compared to measures for increasing output that rely on increasing the size of the device, which involves mechanical losses.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of a heat recovery device according to an embodiment of the present invention, and FIG. 2 is a flow sheet of a conventional heat recovery device. 12... Evaporator, 13... Bypass, 14...
Steam engine, 15... Pipe line, 16... First condenser, 17... Second condenser, 18... First pump, 19... Second pump, 20... Load, 21
... Ejector, 22 ... Pressure reducing valve.

Claims (1)

[Scope of Claims] 1. A steam engine connected to a load, an evaporator for heating a working fluid using waste heat as a heat source and generating working fluid vapor to be supplied to the steam engine, and a steam engine that is discharged from the steam engine. A heat recovery device comprising a condenser for cooling and condensing working fluid vapor, and a pump for circulating the working fluid within the system, further comprising: evaporation. A bypass for detouring a part of the working fluid from the outlet side to the inlet side of the vessel; A second condenser connected in the middle of the bypass; An ejector installed in the bypass upstream of the second condenser; a conduit connecting the ejector to the downstream portion of the second condenser and connected to the cold source side of the condenser; a pressure reducing valve provided between the condenser and the second condenser in the conduit;