KR20010010878A - Method and apparatus of converting heat to useful energy - Google Patents

Abstract

PURPOSE: A method for transforming a heat into a usable energy and an apparatus for performing the same are provided to transform a low temperature of heat into an electric power at a high transforming efficiency. CONSTITUTION: In the method for transforming a heat into a usable energy, an operating fluid(117-17) including a component having a high boiling point and a component having a low boiling point is heated by using an outer heating source(HE-5) in order to providing a heated gas flow. The heated gas flow(16) is separated within the first separator(S) in order to provide the heated gas rich flow including components having a relatively low boiling point and to provide the heated gas lean flow(30) including components having a relatively low boiling point. The heated gas rich flow is expanded in order to provide a consumptive gas rich flow. The expanded consumptive gas rich flow(34) is combined with the heated gas lean flow(30).

Description

METHOD AND APPARATUS OF CONVERTING HEAT TO USEFUL ENERGY}

The present invention relates to a method of executing a thermodynamic cycle for converting heat into a useful form.

Thermal energy is usefully converted into mechanical and then electrical form. The method of converting thermal energy of a low temperature heat source into electric power provides an important area of energy generation. There is a need to increase the efficiency of converting low temperature heat into power.

The thermal energy generated from the heat source can be transformed into mechanical and then electrical form using a working fluid that is generated and expanded in a closed system operating in a thermodynamic cycle. This working fluid contains components having different boiling temperatures and the composition of the working fluid can be changed elsewhere in the system to improve the operating efficiency. Systems for converting low temperature heat into power are described in US Pat. No. 4,346,561 to Alexander I. Kalina; 4,489,563; 4,982,568 and 5,029,444. In addition, systems with multicomponent working fluids are described in US Pat. No. 4,548,043 to Alexander I. Kalina; 4,586,340; 4,604,867; 4,732,005; 4,763,480; 4,899,545; 5,095,708; 5,440,882; 5,572,871 and 5,649,426, which are incorporated herein by reference.

The present invention provides a method and apparatus for executing a thermodynamic cycle. The working fluid, consisting of a low boiling point component and a high boiling point component, is heated by an external heat source (eg, a low temperature heat source) to provide a heated gas working flow. The heated gas working fluid is separated in the first separator to provide a heated gas enrichment having a relatively high boiling point component and a lean stream having a relatively small amount of low boiling component. The heated gas enrichment expands to convert the energy of the enrichment into a useful form and provide an expanded, consumed enrichment. The lean and expanded spent thickening are then combined to provide a working fluid.

Certain embodiments of the present invention have the following features. The working fluid is condensed by transferring heat from the first heat exchanger to the low temperature heat source and then pumps to greater pressure. In the first and second expansion stages, the expanded, partially expanded fluid flow is extracted between each stage and combined with the lean flow. The separator between the expansion stages separates some expanded fluid into vapor and liquid, some or all of the vapor is transferred to the second stage, and some of the vapor is combined with the liquid and then with the lean. The second heat exchanger transfers heat from the reconstituted multicomponent working flow to the condensed multicomponent working flow before condensing under higher pressure. The third heat exchanger transfers heat from the lean to the working flow behind the second heat exchanger. The working flow is divided into two small streams, one of which is heated with external heat and the other is heated in a fourth heat exchanger with heat generated from lean flows; The two streams are then combined to provide a heated gas working stream that is separated in the separator.

Embodiments of the present invention have the following advantages. Embodiments of the present invention can convert low temperature heat into power that exceeds the efficiency of a standard Rankine cycle.

Other advantages and features of the present invention can be clearly understood from the description and the claims.

1 is a diagram illustrating a thermodynamic system for converting heat generated from a low temperature heat source into a useful form.

FIG. 2 is a diagram illustrating another embodiment of the system of FIG. 1 allowing extracts and completely consumables to have different compositions than the fluids under high pressure.

3 is a diagram illustrating an embodiment in which no extracts are present.

4 is a diagram illustrating another embodiment.

In FIG. 1, a system is shown for executing a thermodynamic cycle to obtain useful energy (eg, mechanical energy and electrical energy) from an external heat source. In the above embodiment, the external heat source is a low temperature waste heat stream which flows through the heat exchanger HE-5 in the path shown at 25-26 and heats the working flow 117-17 of the closed thermodynamic cycle. Table 1 shows the states at the numbered positions shown in FIG. Typical output from the system is shown in Table 5.

The working flow of the system shown in FIG. 1 is a multicomponent working flow comprising a component having a low boiling point and a component having a high boiling point. Such preferred working streams are ammonia water mixtures, two or more hydrocarbons, two or more Freons, hydrocarbons and Freon mixtures. In general, the working flow is a mixture of several components with advantageous thermodynamic properties and solubility. According to a particularly preferred embodiment, water and ammonia mixtures are used. In the system shown in FIG. 1, the working flow has the same composition from 13 to 19.

Referring to the system shown in FIG. 1 at the outlet of turbine T, at 34 the flow is referred to as an expanded, spent thickening. This stream is considered to be "rich" in components with low boiling points. This will be mixed with a low concentration, absorbent flow with the same parameters as in 12 to produce a working flow consisting of an intermediate composition under low pressure and with the same parameters as in 13. At 12 the flow is considered to be "lean" in low boiling components.

At all given temperatures, the working flow of the intermediate composition at 13 can condense under low pressure as compared to the high concentration flow at 34. This can draw more power from turbine T and increase process efficiency.

In position 13 the working flow is partially condensed. This flow enters heat exchanger HE-2 where cooling takes place and exits to heat exchanger HE-2 having the same parameters as in 29. This does not fully condense, but only partially condenses. This flow enters the heat exchanger HE-1, which is cooled by flows 23-24 of the coolant and is fully condensed, with the same parameters as in 14. A working flow with the same parameters as in 14 is pumped at a higher pressure to obtain a parameter of 21. The working flow at the 21st position is introduced into the heat exchanger HE-2 which is heated by the working flow at the 13-29 position to a point with 15 parameters. The working flow with a parameter of 15 enters the heat exchanger HE-3 which is heated to obtain 16 parameters. According to a typical structure, the 16 points are exactly at the boiling point, but need not be. In the 16th position, the working flow is divided into two small flows, the first working flow 117 and the second working flow 118. The first working flow with a parameter of 117 points is sent to the heat exchanger HE-5 and maintains a parameter of 17. It is heated by an external heat source, flows 25-26. Another small flow, the second working small flow 118, is introduced into the heat exchanger HE-4 which is heated to obtain a parameter of 18. The two operating small flows 17, 18 exiting the heat exchangers HE-4 and HE-5 are combined to form a heated, gas working flow having a parameter of 19. This stream is partly or completely steamy. According to a preferred embodiment, the 19 points are only partially vaporized points. At point 19 the working flow occurs at 13 and fully condenses at 14, pumped at high pressure at 21, and has the same intermediate composition preheated to 15 and 16. This enters separator S. It is separated into a subsaturated vapor, named "heated gas enrichment" and having a parameter of 30, and an empty saturated liquid, named "rare" and having a parameter of 7. At 7, lean (saturated liquid) enters the heat exchanger HE-4, which cools the working stream 118-18 during heating. At 9 the lean is discharged to the heat exchanger HE-4 with a parameter of 8. It is adjusted to the appropriately selected pressure and has 9 parameters.

At 30, the heated gas enrichment (saturated vapor) is discharged to separator S. This flow enters turbine T, which expands to low pressure, providing useful mechanical energy to turbine T, which is used to generate electricity. Some expanded streams with a parameter of 32 are extracted from turbine T at medium pressure (approximately 9 points of pressure) and this extract 32 (the "second part" of some expanded thickening, additionally expanded "agent" 1 part ") is mixed with 9 points of lean to produce a binding flow having a parameter of 10. The lean stream having a parameter of 9 points functions as an absorption stream for the extract stream 32. The final flow with 10 parameters (lean and second part) enters the heat exchanger HE-3 where cooling takes place and heats the working flows 15-16 to a point with 11 parameters. The 11 parameter flow is then regulated to 34 pressures, resulting in 12 parameters.

Returning to turbine T, not all of the turbine inflow is extracted at 32 with some expanded state. The remainder, referred to as the first part, is expanded to a properly selected low pressure and discharged to turbine T at 34. This cycle ends.

In the embodiment shown in Fig. 1, the extraction process of 32 points has the same composition as the flow of 30 and 34 points. In the embodiment shown in FIG. 2, the turbine is represented by a first turbine stage T-1 and a second turbine stage T-2, with some expanded thickening exiting the turbine's high pressure stage T-1 at 31. The state of the numbered parts shown in FIG. 2 is shown in Table 2. Typical outputs from the system of FIG. 2 are shown in Table 6.

In FIG. 2, the partially enriched thickening from the first turbine stage T-1 is divided into a first portion of 33 points inflated in the low pressure turbine stage T-2 and a 32 to second portion combined with lean in 9. . Some expanded thickening enters separator S-2, where it is divided into steam and liquid. The composition of the second portion at 32 may be chosen to optimize its efficiency when mixed with steam at 9. Separator S-2 causes the flow 32 to dilute as saturated liquid at the pressure and temperature obtained in separator S-2; In this case, stream 33 becomes saturated steam under the conditions obtained in separator S-2. By selecting the amount of mixture in stream 133, the amount of saturated liquid and saturated vapor in steam 32 can be varied.

The embodiment of FIG. 3 differs from the embodiment of FIG. 1 in that the heat exchanger HE-4 is omitted and some expanded flow cannot be extracted from the turbine stage. In the embodiment of FIG. 3, the hot stream discharged to separator S goes directly to heat exchanger HE-3. The states at the points shown in FIG. 3 are shown in Table 3. Typical output from this system is shown in Table 7.

The embodiment of FIG. 4 differs from the embodiment of FIG. 3 in that the heat exchanger HE-2 is omitted. The states in the numbered parts shown in FIG. 4 are shown in Table 4. Typical output from this system is shown in Table 8. Omitting the heat exchanger HE-2 may reduce the efficiency of the process, but it is economically advantageous under conditions where the increased power does not incur the additional cost of the heat exchanger.

In general, standard equipment can be applied to practice the method according to the invention. Thus, equipment such as heat exchangers, tanks, pumps, turbines, valves and fittings of the type used in common Rankine cycles can be applied to practice the method according to the invention.

In an embodiment of the invention, the working fluid is expanded to drive a turbine of known type. However, expanding the working fluid to the low pressure consumed at a high pressure filled to release energy can be accomplished by means of a device according to the prior art, which is known to those skilled in the art. The energy thus released can be stored and used by various methods known to those skilled in the art.

As the separator according to the above-described embodiment, a specific gravity separator such as a flash tank according to the prior art may be used. The device according to the prior art used to form two or more streams of different composition from a single stream can be used to form lean and thick streams from fluid working flow.

The condenser may be a kind of known heat removal device. For example, the condenser may take the form of a heat exchanger such as a water cooling system or another type of condenser.

Various types of heat sources can be used to drive the cycle according to the invention.

Claims (24)

Heating a working fluid comprising a high boiling component and a low boiling component to an external heat source to provide a heated gas working flow, Separating the heated gas working stream in the first separator to provide a heated gas enrichment having a relatively high boiling point component and a lean stream having a relatively low boiling point component, Transform the fluid energy into a usable form and inflate the heated gas enrichment to provide an expanded, consumed enrichment, A method of conducting a thermodynamic cycle consisting of combining a spent thick and a lean inflated to provide a working fluid. The method of claim 1, wherein after joining and before heating to an external heat source, the working fluid is condensed by transferring heat from the first heat exchanger to the cold heat source, and then pumped at a higher pressure. The method of claim 1, wherein expansion occurs in the first, expansion, and second expansion phases, The heated gas enrichment is partially expanded to provide some expanded enrichment in the first expansion stage, Dividing some of the expanded thickening into first and second portions, The first portion is expanded to provide a spent thickening, which is expanded in a second expansion step, Combining the second portion of the lean before combining the lean and the expanded, spent thickening. 3. The method of claim 2 including transferring heat from the working fluid before the working fluid is condensed, in the second heat exchanger to the working fluid after the working fluid is pumped to high pressure and before heating to an external heat source. How to feature. 3. The method of claim 2 including transferring heat from the lean to the working fluid after the working fluid is pumped to high pressure in a third heat exchanger before heating to an external heat source. 5. The method of claim 4, comprising transferring heat from the lean to the working fluid after the working fluid absorbs heat in the second heat exchanger and before heating to an external heat source. . 3. The process of claim 2, wherein after applying a pumping action and before heating to an external heat source, dividing the working fluid into a first working subflow and a second working subflow, wherein the heating with an external heat source comprises Heating the first working subflow with an external heat source to provide a thermally coupled first working subflow with a second working subflow to provide a heated gas working fluid. . 8. The method of claim 7, including transferring heat from the lean to the second working subflow in a fourth heat exchanger. The method of claim 1 wherein heating to an external heat source is performed in a fifth heat exchanger. 4. The method of claim 3, wherein the dispensing process divides the portion of the expanded thickening into a vapor portion and a liquid portion, the first portion comprising a steam portion and the second portion comprising a liquid portion. The method of claim 10 including combining the liquid and some vapor portions to provide a second portion. 4. A method according to claim 3, comprising transferring heat in a heat exchanger, from lean flow having a second portion to working fluid before the working fluid is heated to an external heat source. A heater for heating a working fluid comprising a low boiling point component and a high boiling point component to an external heat source to provide a heated gas working fluid, A first separator connected to receive the heated gas working fluid and generate a heated gas enrichment having a high boiling point component and a lean having a small boiling point component, An expander connected to receive the heated gas enrichment, transform it into a form that can utilize fluid energy, and generate an expanded, consumed enrichment, And a first fluid mixer coupled to the lean and the expanded, spent thickening and producing a working fluid, the output of the fluid mixer being coupled to an input of the heater. 14. The apparatus of claim 13, comprising a pump connected between the first heat exchanger and the first fluid mixer and the heater, the first heat exchanger condensing the working fluid by transferring heat to a low temperature heat source, wherein the pump is operated at high pressure. Apparatus characterized in that acts on. 14. The inflator of claim 13, wherein the inflator comprises a first expansion step and a second expansion step, The first expansion stage is connected to receive the heated gas enrichment and generate a partially expanded enrichment, A fluid distribution device connected to receive some expanded thickening and divide it into first and second portions, The second step expands the first portion to provide a spent thickening that is connected and expanded to receive the first portion, And a second fluid mixer connected to couple the second portion with the lean before the lean is expanded with the spent thickening in the first fluid mixer. 15. The apparatus of claim 14, further comprising a second heat exchanger coupled to transfer heat from the working fluid prior to condensation of the working fluid to the working fluid after the working fluid is pumped at high pressure in the pump and before heating from the heater to an external heat source. Device characterized in that. 15. The apparatus of claim 14, comprising a third heat exchanger coupled to transfer heat from the lean to the working fluid after the working fluid is pumped to high pressure at the pump but before heating from the heater to an external heat source. 17. The apparatus of claim 16, wherein the working fluid comprises a third heat exchanger coupled to transfer heat from the lean to the working fluid after receiving heat in the second heat exchanger and before heating from the heater to an external heat source. . The method of claim 14, The pump is connected to divide the working fluid into a first operating subflow and a second operating subflow after applying the pump action in the pump and before heating from the heater to an external heat source, the heater operating to provide a heated first operating subflow. Heating the subflow, And a third fluid mixer coupled to couple the heated first operating subflow with the second operating subflow to provide a heated gas working fluid. 20. The apparatus of claim 19, comprising a fourth heat exchanger coupled to transfer heat from the lean to the second operating subflow. The apparatus of claim 13 wherein the heater is a fifth heat exchanger. The flow distribution apparatus of claim 15, wherein the flow distribution device comprises a second separator, the second separator being connected to receive some expanded thickening and to separate it into a vapor portion and a liquid portion, the first portion comprising a portion of the steam portion. And the second portion comprises a liquid portion. 23. The device of claim 22, wherein the flow distribution device comprises a fourth fluid mixer connected to join the liquid portion supplied from the second separator and the steam portion supplied from the second separator to provide a second portion. . The apparatus of claim 15 comprising a heat exchanger connected to transfer heat from the lean to the working fluid having a second portion before the working fluid is heated to an external heat source in the heater.