KR101417634B1 - Apparatus for Converting Thermal Energy - Google Patents

Abstract

The present invention relates to an apparatus for converting thermal energy which enables high concentration by using a heating source of hot liquid discharged from a gas and liquid separator as a heating source required for concentrating fluid, allows an evaporator, an energy converting means, a condenser, and a first pumping means to be connected, and uses working fluid in which two or more types of fluids having different boiling points are mixed. The apparatus for converting the thermal energy comprises a first separator which receives an evaporation working fluid between the evaporator and the energy converting means to separate the fluid into a first thick flow and a first rare flow; a joining unit for joining the first thick flow and the first rare flow which pass through the energy converting means; a throttle valve which is arranged between the joining unit and the first separator to lower the pressure of the first rare flow to be the same pressure of the first thick flow passed through the energy converting means; a first heat exchanger which is located at a front end of the evaporator and allows the first rare flow and the working fluid passed through the first pumping means to be heat-exchanged; a second separator which is located between the first heat exchanger and the evaporator and receives the heat-exchanged working fluid to separate the fluid into a second thick flow and a second rare flow; a second heat exchanger which allows the second rare flow to be branched to be joined with the first rare flow or to be joined with the second thick flow and condenses the working fluid in which the second rare flow and the second thick flow are joined; and a second pumping means which pumps the working fluid between the second heat exchanger and the evaporator with high pressure, wherein the second heat exchanger allows the working fluid in which the second rare flow and the second thick flow are joined to be heat-exchanged with the working fluid before flowing into the first heat exchanger.

Description

[0001] Apparatus for Converting Thermal Energy [

The present invention relates to a device for converting heat energy from a heat source by using a working fluid expanded and regenerated, and more specifically, a thermodynamic cycle for switching low temperature heat energy using two or more mixed working fluids, To an apparatus for converting thermal energy capable of raising power generation efficiency by having ammonia concentration.

Thermal power plants using coal, oil or gas as fuel typically use water as the working fluid. In the case of LNG combined-cycle power generation, since the exhaust gas from the gas turbine is high at 500 to 600 ° C., the steam is converted into steam and the steam turbine is driven to generate electricity.

A low-temperature and low-temperature array power generation technology is being developed and expanded at a temperature of 100 to 500 ° C for generating electricity using an array source having a temperature lower than that of a conventional steam generator. To develop at low temperatures, a working fluid with a boiling point at a low temperature, i.e. a refrigerant or a hydrocarbon-based fuel, is used. The organic rankine cycle system, the kalina cycle, and the uehara cycle system, depending on the characteristics of the working fluid or the system configuration. The organic Rankine cycle utilizes a single working fluid, while the Carina and Uehara cycle systems use a mixture of ammonia and water.

The organic Rankine cycle, which is a normal Rankine cycle, is composed of basic elements of an evaporator 40, a turbine 50, a condenser 20 and a pump 30 as shown in FIG. 1, and the generator 50 is connected to the turbine 50, And converts the mechanical energy converted by the turbine 50 into electric energy. The evaporator 40 is a place where the working fluid is phase-changed to a gas by heat and the turbine 50 serves to change the pressure difference between the evaporator 40 and the condenser 20 to a work. The condenser 20 is a turbine 50) from the low-temperature low-pressure working fluid to the liquid. The pump 30 serves to supply the low-pressure working fluid in the condenser to the evaporator.

In this Rankine cycle, the low-temperature and low-pressure working fluid 1 passes through the pump 30 and becomes the working fluid 2 of low temperature and high pressure, becomes the working fluid 3 of high temperature and high pressure while passing through the evaporator 40, After passing through the turbine 50, the working fluid 4 becomes a low-pressure working fluid 4, and then through the condenser 20, the working fluid 1 becomes a low-temperature low-pressure working fluid again. do.

The organic Rankine cycle differs from the Rankine cycle in that it is a working fluid that evaporates at low temperatures using organic materials with a lower boiling point than water. Organic Rankine cycle is an organic material in which the working fluid consists of one component.

On the other hand, the Carina cycle uses ammonia water mixed with water and ammonia as a working fluid, unlike the organic Rankine cycle which uses a pure substance as a working fluid. 2, the low-temperature and low-pressure working fluid 1 is discharged to the high-pressure working fluid 2 through the pump 30 and is preheated in the preheater or regenerator 45, do. Thereafter, the gas is vaporized through the evaporator 40 to become a high-temperature high-pressure working fluid 3, and the working fluid 3 flows into the gas-liquid separator 60. Here, the saturated liquid containing a large amount of water is separated into a lean stream (7) containing little ammonia and a concentrated stream (6), which is a saturated steam which is mainly composed of ammonia. The concentrated stream (6) is supplied to the turbine The turbine 50 converts the chemical energy into mechanical energy and the mechanical energy produces electricity through the generator (not shown), and then the enrichment 6 is converted into the consumed enrichment 11 ).

The lean stream 7 in a high temperature state is sent to a preheater or regenerator 45 to recover the heat while preheating the working fluid 2 to become a heat exchanged lean flow 8. The reheated lean stream 8 is supplied to a throttle valve The pressure is lowered to the pressure at the rear end of the turbine 50 and becomes the lean stream 9 of low pressure. The low-pressure diluent 9 and the spent rich stream 11 are mixed in the absorber 80 to become the working fluid 10. The working fluid 10 is supplied to the condenser 11 and becomes the working fluid 1 in a state where the working fluid 10 is condensed by the cooling water of low temperature.

The heating fluid having a high temperature heat source is supplied to and discharged from the evaporator 40, and the cooling water is supplied to and discharged from the condenser 20. The carina cycle can regulate the opening of the pressure controller 70 while adjusting the level of the gas-liquid separator 60.

In order to increase the amount of power generated by the turbine 50 in the design of the carina cycle, the pressure difference between the front end and the rear end of the turbine 50 must be large. However, in a working fluid consisting of water and ammonia, the ammonia has a low evaporation temperature, the higher the ammonia concentration, the higher the pressure at the downstream end of the turbine, and the lower the ammonia concentration at the downstream end of the turbine, There is a problem in that the amount of evaporation of the working fluid is small and the power generation amount is small.

It is an object of the present invention to provide an apparatus for switching thermal energy capable of achieving a low pressure at the rear end of a turbine while achieving a high pressure at the front end of the turbine.

The present invention aims at achieving high concentration by utilizing a heat source of a hot liquid discharged from a gas-liquid separator as a heat source necessary for concentrating a concentration of a fluid.

In order to achieve the above object, the present invention provides an apparatus for converting heat energy as follows.

The present invention relates to an evaporation apparatus for evaporating a working fluid by heat exchange with a high temperature fluid, an energy conversion means for converting the chemical energy of the working fluid vaporized through the evaporator into mechanical energy, Wherein the working fluid is a mixture of two fluids with different boiling points of at least two, and wherein the working fluid is evaporated between the evaporator and the energy conversion means A first separator for receiving the working fluid and separating the working fluid into a first enriched stream and a first diluent; A merging portion in which the first rich stream having passed through the energy conversion means and the first lean mixture join together; A throttle valve disposed between the merging portion and the first separator to lower the first lean flow to the same pressure as the first rich flow that has passed through the energy conversion means; A first heat exchanger located at a front end of the evaporator and performing heat exchange between the hot fluid passing through the evaporator and a working fluid passing through the first pumping means; A second separator positioned between the first heat exchanger and the evaporator and receiving a heat exchange working fluid to separate into a second rich stream and a second diluted vapor; A second heat exchanger for condensing a working fluid in which the second diluent and the second rich stream are combined, the second diluent being either merged with the first diluent or branched to merge with the second rich stream; And a second pumping means for pumping the working fluid between the second heat exchanger and the evaporator at a high pressure, wherein in the second heat exchanger, a working fluid, in which the second diluent and the second rich stream are combined, A device that converts heat energy to heat exchange with the working fluid before it enters the heat exchanger.

In this case, the working fluid passing through the second pumping means may be further exchanged with the working fluid before the condenser or the first dilution.

The throttle valve may further include: a first throttle valve for lowering the lean flow passing through the first heat exchanger to a pressure that is pressurized by the first pumping means; And a second throttle valve disposed between the merging portion and the first throttle valve.

Wherein the additional heat exchanger further comprises a third heat exchanger that is heat exchanged between the first diluent and the working fluid that has passed through the second pumping means and is continuously disposed in the first separator, a second heat exchanger disposed between the first throttle valve and the second throttle valve A fourth heat exchanger in which a combined lean flow after the second lean flow is joined to the first lean flow and a working fluid which has passed through the second pumping means heat-exchange; and a fourth heat exchanger, And a fifth heat exchanger through which the working fluid passed through the pumping means undergoes heat exchange.

The present invention may include a branch portion that is disposed between the second heat exchanger and the first pumping means and supplies the working fluid passing through the second heat exchanger or the working fluid that has passed through the second separator and the second heat exchanger .

Further, in the present invention, the working fluid may include ammonia and water.

The present invention can provide an apparatus for converting heat energy capable of achieving a low pressure at the rear end of a turbine while achieving high pressure at the front end of the turbine through the heat energy switching means.

Further, the present invention can achieve high concentration by utilizing the heat source of the hot liquid discharged from the gas-liquid separator as a heat source necessary for concentrating the concentration of the fluid.

1 is a block diagram of a conventional Rankine cycle.
2 is a configuration diagram of a conventional Carina cycle.
3 is a schematic diagram of an apparatus for converting heat energy according to the present invention.
4 is another schematic diagram of an apparatus for converting heat energy according to the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the embodiment of the present invention, a mixture of water and ammonia is used as a working fluid. However, the present invention corresponds to the working fluid of the present invention when two or more fluids having different boiling points are mixed and used.

In the cycle of switching the thermal energy, electric power is generated from a generator connected to an energy conversion means such as a turbine. In the turbine, the amount of energy generated by the difference between the pressure on the input side and the pressure on the output side is determined. The efficiency of the cycle can be improved if the pressure on the output side can be increased or the pressure on the output side can be lowered.

Generally, the input side pressure is determined by the pressure pumped by the pump, which is connected to the temperature at which it is evaporated, so that water and ammonia, which use the medium-low temperature as the heat source, There is a limit to doing. However, when a mixture of water and ammonia is used as the working fluid, the lower the ammonia concentration, the lower the condensation at the same temperature, the lower the pressure at the downstream and the output side of the turbine.

Since the pressure at the front end of the turbine does not change even if the pressure at the rear end of the turbine is lowered, the pressure difference between the front end and the rear end of the turbine increases, and the amount of energy that the turbine can convert increases.

2, which is a typical carina cycle. However, in order to achieve a low pressure at the rear end of the turbine, a low concentration working fluid is concentrated once at a medium concentration, heated and separated to obtain a high concentration ammonia vapor To the turbine. Accordingly, since the downstream portion of the turbine has a low concentration of ammonia, it is possible to lower the pressure to a lower level and thus has an operation structure that has an advantage of obtaining a high turbine output.

In particular, in order to increase the ammonia concentration at the intermediate pressure, a working fluid of a medium pressure is heated by using a high-temperature lean stream immediately out of the gas-liquid separator passed through the evaporator, and then passed through a gas-liquid separator to produce a working fluid having a desired concentration of ammonia Provided as an evaporator.

Figure 3 is a schematic diagram of one embodiment of the present invention.

The working fluid P1 having passed through the condenser 20 into which the cooling water flows 23 and flows out 24 passes through the first pumping means 30 and is pressurized to the medium pressure working fluid P2. The pressurized medium-pressure working fluid P2 passes through a flow control valve 31 which regulates the flow rate of the medium-pressure working fluid P2, which regulates the amount of working fluid circulating the whole cycle .

The intermediate pressure working fluid P3 that has passed through the flow rate control valve 31 is branched at the branching section P4 and part of the branching section P4 is connected to the second gas-liquid separator 60 and the second heat exchanger 91 And the remaining part thereof is sent to the second heat exchanger 91 and heat-exchanged with the working fluid P11 to become the temperature-rising intermediate working fluid P5.

The working fluid P5 is sent to the first heat exchanger 95 connected to the evaporator 40 so as to be able to exchange heat with the high temperature fluid passing through the evaporator 40. In the first heat exchanger 95, And is heated to become a vaporized working medium pressure working fluid P6.

The heating medium pressure working fluid P6 has a relatively high concentration of ammonia in the second gas-liquid separator 60, a relatively low concentration of the second rich stream P7 and ammonia in the gaseous state, and a second dilute liquid P8). The second rich stream P7 merges with a portion of the second diluent P8 and is then supplied to the second heat exchanger 91 and the second pumping means 35.

On the other hand, the second diluent P8 is branched so as to merge with the second rich stream P7 at the branching section P9 and to merge with the first diluent P22 at the other middle pressure. At this time, the concentration of ammonia in the subsequent working fluid can be adjusted by adjusting the amount of the second diluent P8 joining the second rich stream P7 at the branching section P9.

The working fluid P10 in which the second dilute fluid P8 and the second rich fluid P7 are combined flows through the second heat exchanger 91 while being heat exchanged with the intermediate pressure working fluid P3, The working fluid P12 is supplied to the second pumping means 35 and the working fluid P12 is supplied to the second pumping means 35. [ .

The second pumping means 35 pressurizes the working fluid P12 to a high pressure to produce a high-pressure working fluid P13. The high pressure working fluid P13 is sent to the fifth heat exchanger 92 so as to heat exchange with the working fluid P27 that has passed through the merging portion 80 where the low pressure lean P25 and the consumed rich flow P26 are merged And is heated to become the working fluid P14. In the fifth heat exchanger (92), the heat of the working fluid (P27) is transferred to the high-pressure working fluid (P13).

The working fluid P14 that has passed through the fifth heat exchanger 92 is supplied to the first diluent P21 between the first throttle valve 96 and the second throttle valve 97 and the second diluent P8 And the working fluid P14 passed through the fifth heat exchanger 92 is supplied to the fourth heat exchanger 93 for heat exchange and the fourth heat exchanger 93 is supplied to the fourth heat exchanger 93. [ And becomes a working fluid P15 that has been heated while being heated while passing through it. In the fourth heat exchanger (93), the heat of the joining diluent (P29) is transferred to the working fluid (P14).

The working fluid P15 having passed through the fourth heat exchanger 93 is supplied to the third heat exchanger 94 so as to perform heat exchange with the first rare gas P20 that has passed through the first heat exchanger 95. [ The third heat exchanger 94 is connected to the first gas-liquid separator 65 to transfer the heat of the first rare gas P19 to the working fluid P15. The working fluid P16 that has passed through the fourth heat exchanger 93 is supplied to the evaporator 40. [

In the evaporator 40, the working fluid P16 undergoes heat exchange with the high-temperature fluid, and a large amount of the working fluid becomes vaporized high-temperature working fluid P17. The high temperature fluid flows into the evaporator 40 through the inlet 25 and the outlet 26 and the fluid corresponding to the array source between 100 and 500 DEG C may be used. The high-temperature fluid that has passed through the evaporator 40 is supplied to the first heat exchanger 95 to heat the temperature-rising medium-pressure working fluid P5 as described above.

The high temperature working fluid P17 that has passed through the evaporator 40 is supplied to the first gas-liquid separator 65 and is separated into the first rich stream P18 and the first rare gas P19 in the first gas- do. The first rich stream P18 is supplied to the turbine 50 corresponding to the energy conversion means and converts the chemical energy it has to the mechanical energy as the pressure and the temperature decrease while passing through the turbine 50. [ Generally, the mechanical energy converted by the turbine 50 is converted back to electrical energy through a generator (not shown).

On the other hand, in the first gas-liquid separator 65, the first rare gas P19 having a low ammonia concentration passes through the third heat exchanger 94 in a state of high temperature and high pressure, (P20), which is lowered in temperature after delivery. The first rare gas P20 that has passed through the third heat exchanger 94 passes through the first throttle valve 96 and is lowered by the pressure of the first pumping means 30 so that the first rare gas P21 do. The intermediate pressure first lean pump P21 is brought into contact with the second lean pump P8 and the merging portion P22 to become the merging lean flow P23.

The combined lean sparge P23 is supplied to the fourth heat exchanger 93 and transfers the heat energy that has been flowing through the fourth heat exchanger 93 to the working fluid P14. Pressure lean flow P25 which is the same as the pressure at the downstream end of the turbine 50 while passing through the second throttle valve 97 and the low pressure lean flow P25 is the consumed rich flow P26 And the merging portion 80, and becomes the working fluid P27.

The working fluid P27 is supplied to the fifth heat exchanger 92 to transfer the heat to the working fluid P13 and then to the condenser 20 so that the working fluid P27 is condensed into the liquid.

In the present invention, the difference in ammonia concentration between the high-pressure portion at the front end of the turbine 50 and the low-pressure portion at the downstream end of the turbine 50 is large, so that it is possible to utilize the advantage that the turbine 50 performing the isentropic movement can obtain a high dropout. Particularly, in the present invention, the heat source of the first leachate P19 separated from the first gas-liquid separator 65 is utilized in order to ensure sufficient energy for vaporizing the medium-concentration working fluid for high concentration.

Since the energy for vaporizing the medium working fluid is secured, the condensed working fluid can be configured at a low concentration, a small amount of power is used to pressurize the low working fluid, and the flow rate of the medium working fluid is reduced, The pressurizing power is reduced at a high pressure. That is, the pump power can be reduced as compared with the case of constructing the working fluid at one concentration.

On the other hand, Fig. 4 shows another embodiment of the present invention.

As shown in FIG. 4, only the embodiment of FIG. 3 and the third to fifth heat exchangers 92, 93 and 94 are different, and the rest of the configuration is the same.

4, the third and fifth heat exchangers 92 and 94 are not provided and only the fourth heat exchanger 93 is provided. However, if necessary, the third or fifth heat exchangers 92 and 94 may be omitted, . That is, at least one of the third to fifth heat exchangers 92, 93, 94 may be selectively applied to the heat energy conversion apparatus of the present invention.

Example

A working fluid having an ammonia concentration of 55% and a temperature of 32 ° C was used as the working fluid P1 at the rear stage of the condenser 20 and 13bara and 36bara were applied as a medium pressure and a high pressure. To provide the first enrichment stream (P18). 6.22 kW in the first pumping means 30 which pressurizes to medium pressure and 18.1 kW in the second pumping means 35 which pressurizes with high pressure were used as power and 4239 kW of thermal energy was supplied to the evaporator (40). In this embodiment, a thermal efficiency of 13.5% was obtained, and an actual thermal efficiency of 12.9% was obtained considering that the actual efficiency of the pumping means 30, 35 was 50%.

The concentration, temperature and pressure values at the main points are shown in [Table 1].

Point density(%) Temperature (℃) pressure P1 55 32 4.8bara P7 97.14 - 13bara P11 - 35 13bara P13 62 35 36bara P15 62 78 36bara P16 62 95.5 36bara P17 62 142 36bara P18 92.81 142 36bara P20 42.27 80 36bara P26 92.81 62.2 4.8bara

On the other hand, in the case of the carina cycle (see FIG. 2) having the same condition of the downstream end of the condenser and the turbine shear condition, the pump theoretical power is 36.45 kW, and the thermal energy required for the evaporator is 4189 kW to obtain the generator output of 600 kW, %, And when considering the actual efficiency of the pump, an actual thermal efficiency of 12.6% can be obtained.

Therefore, in the case of the thermal energy conversion device according to the embodiment of the present invention, the efficiency can be increased more than the conventional thermal energy conversion device. Particularly, by exchanging heat with the first dilute gas at a high pressure from a medium pressure, ammonia concentration can be easily controlled, pump power can be reduced, and condenser load can be reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

20: condenser 30: first pumping means
35: second pumping means 40: evaporator
50: turbine 60: second gas-liquid separator
65: first gas-liquid separator 80:
91: second heat exchanger 92: fifth heat exchanger
93: fourth heat exchanger 94: third heat exchanger
95: first heat exchanger

Claims (8)

An evaporator for evaporating the working fluid by heat exchange with the high temperature fluid, an energy converting means for converting the chemical energy of the working fluid vaporized through the evaporator into the mechanical energy, a condenser for condensing the working fluid having passed through the energy converting means to the liquid, A first pumping means is connected to pressurize the condensed working fluid and the working fluid is a mixture of two fluids having different boiling points of at least two,
A first separator for receiving an evaporative working fluid between the evaporator and the energy conversion means and separating the evaporated working fluid into a first enriched stream and a first diluent;
A merging portion in which the first rich stream having passed through the energy conversion means and the first lean mixture join together;
A throttle valve disposed between the merging portion and the first separator to lower the first lean flow to the same pressure as the first rich flow that has passed through the energy conversion means;
A first heat exchanger located at a front end of the evaporator and performing heat exchange between the hot fluid passing through the evaporator and a working fluid passing through the first pumping means;
A second separator positioned between the first heat exchanger and the evaporator to receive the heat-exchanged working fluid and separate the second working fluid and the second lean fluid; The second diluent joins with the first diluent or branches to join with the second rich stream,
A second heat exchanger for condensing the working fluid in which the second diluent and the second rich stream are combined; And
And second pumping means for pumping the working fluid to a high pressure between the second heat exchanger and the evaporator,
Wherein the second heat exchanger converts the heat energy to be heat-exchanged with the working fluid before the working fluid in which the second diluent and the second rich stream are combined flows into the first heat exchanger.
The method according to claim 1,
Further comprising an additional heat exchanger for exchanging heat between the working fluid passing through the second pumping means and the working fluid or the first diluent before the condenser.
3. The method of claim 2,
Wherein the additional heat exchanger includes a third heat exchanger that is heat exchanged between the first diluent and the working fluid passing through the second pumping means and is continuously disposed in the first separator.
3. The method of claim 2,
The throttle valve
A first throttle valve for lowering the lean flow passing through the first heat exchanger to a pressure which is pressurized by the first pumping means; And
And a second throttle valve disposed between the merging portion and the first throttle valve,
Wherein the additional heat exchanger is a fourth throttle valve having a fourth throttle valve and a fourth throttle valve, wherein the additional heat exchanger is a fourth throttle valve and the fourth throttle valve is a fourth throttle valve, And a heat exchanger.
3. The method of claim 2,
Wherein the additional heat exchanger comprises a fifth heat exchanger for exchanging heat between the working fluid passing through the merging section and the working fluid passing through the second pumping means.
The method of claim 3,
The throttle valve
A first throttle valve for lowering the lean flow passing through the first heat exchanger to a pressure which is pressurized by the first pumping means; And
And a second throttle valve disposed between the first throttle valve and a merging portion where the consumed rich stream and the first lean flow are merged,
The additional heat exchanger
A fourth heat exchanger in which a combined lean flow between the first throttle valve and the second throttle valve after the second lean flow merges into the first lean flow and a working fluid that has passed through the second pumping means; And
And a fifth heat exchanger in which the working fluid having passed through the merging section where the consumed rich stream having passed through the energy switching means and the first dilute fluid have passed through the additional heat exchanger and the working fluid having passed through the second pumping means undergoes heat exchange And the heat energy is converted into heat energy.
7. The method according to any one of claims 1 to 6,
And a branching portion which is disposed between the second heat exchanger and the first pumping means and which divides the working fluid passing therethrough so as to join the working fluid passing through the second heat exchanger or toward the second heat exchanger, / RTI >
7. The method according to any one of claims 1 to 6,
Characterized in that the working fluid comprises ammonia and water.

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