MXPA99007205A - Method and apparatus for converting heat into useful energy - Google Patents

Abstract

Un método y aparato para implementar un ciclo termodinámico. Se separa una corriente de trabajo gaseosa calentada que incluye un componente de bajo punto de ebullición y un componente de más alto punto de ebullición, y se expande el componente de bajo punto de ebullición para transformar la energía de la corriente a una forma utilizable, y para proporcionar una corriente expandida relativamente rica. Esta corriente rica expandida se divide entonces en dos corrientes, una de las cuales se expande adicionalmente para obtener más energía, dando como resultado una corriente gastada, la otra de las cuales se extrae. La corriente magra no expandida y la corriente rica gastada se combinan luego en un subsistema regenerador con la corriente extraída, para reproducir la corriente de trabajo, la cual entonces se calienta de una manera eficiente en un calentador para proporcionar la corriente de trabajo gaseosa calentada que se separa.

Description

METHOD AND APPARATUS FOR CONVERTING HEAT IN USEFUL ENERGY Background of the Invention The invention relates to the implementation of a thermodynamic cycle to convert heat to a useful form. Thermal energy can be converted usefully into a mechanical, and then electrical, form. The methods for converting thermal energy from low temperature heat sources into electrical energy present an important area of power generation. There is a need to increase the efficiency of the conversion of this low temperature heat to electrical energy. The thermal energy from a heat source can be transformed into a mechanical, and then electrical, form using a working fluid that expands and regenerates in a closed system that operates on a thermodynamic cycle. The working fluid can include components of different boiling temperatures, and the composition of the working fluid can be modified in different places within the system, to improve the efficiency of the operation. Systems that convert low temperature heat into electrical energy are described in the United States Patents of Alexander I. Kalina Numbers 4,346,561; 4,489,563; 4,982,568; and 5,029,444. In addition, systems with multi-component working fluids are described in Alexander I's United States Patents. Kalina Numbers 4,548,043; 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.

SUMMARY OF THE INVENTION The invention generally provides a method and system for implementing a thermodynamic cycle. A working stream that includes a low-boiling component and a higher-boiling component is heated with an external heat source (eg, a low-temperature source) to provide a heated gaseous work stream . The heated gaseous work stream is separated in a first separator, to provide a stream rich in heated gas having relatively more of the low boiling component, and a lean stream having relatively less of the low boiling component. The heated gas rich stream is expanded to transform the energy of the stream into a useful form, and to provide a stream rich in expanded spent gas. The lean current and the expanded gas rich in expanded gas are then combined to provide the working current.

The particular embodiments of the invention may include one or more of the following characteristics. The working current is condensed by transferring heat to a low temperature source in a first heat exchanger, and then it is pumped at a higher pressure. The expansion takes place in a first expansion stage and in a second expansion stage, and a partially expanded fluid stream is drawn between the stages, and combined with the lean stream. A separator between the stages of the expander separates a partially expanded fluid into vapor and liquid portions, and some or all of the vapor portion is fed into the second stage, and some of the vapor portion can be combined with the liquid portion, and then it is combined with the lean current. A second heat exchanger in a recuperative way transfers the heat from the reconstituted multi-component work stream (before condensation) to the condensed multi-component work stream at a higher pressure. A third heat exchanger transfers the heat from the lean current to the working current after the second heat exchanger. The working current is divided into two subcurrents, one of which is heated with external heat, the other of which is heated in a fourth heat exchanger, with heat from the lean current; the two streams are then combined to provide the heated gaseous work stream that separates in the separator.

The embodiments of the invention may include one or more of the following advantages. The embodiments of the invention can achieve heat conversion efficiency at low temperature in electrical energy that exceeds the efficiency of conventional Rankine cycles. Other advantages and features of the invention will become clearer from the following detailed description of the particular embodiments, and from the claims.

Brief Description of the Drawing Figure 1 is a diagram of a thermodynamic system for converting heat from a low temperature source to a useful form. __ Figure 2 is a diagram of another embodiment of the system of Figure 1, which allows an extracted current and a fully spent current to have compositions that are different from the current charged at high pressure. Figure 3 is a diagram of a simplified mode where there is no extracted current. Figure 4 is a diagram of an additional simplified mode.

Detailed Description of the Invention Referring to Figure 1, there is shown a system for implementing a thermodynamic cycle to obtain useful energy (e.g., mechanical, and then electrical energy) from an external heat source. In the example described, the external heat source is a low temperature waste heat water stream that flows in the path represented by points 25-26 through the heat exchanger HE-5, and heats the working current 117-17 of the closed thermodynamic cycle. Table 1 presents the conditions in the numbered points indicated in Figure 1. A typical output from the system is presented in Table 5. The working current of the system of Figure 1 is a multi-component working stream that includes a Low boiling point component, and a high boiling component. This preferred work stream can be a mixture of ammonia-water, two or more hydrocarbons, two or more freons, mixtures of hydrocarbons and freons, or the like. In general, the working stream can be mixtures of any number of compounds with favorable thermodynamic characteristics and solubility. In a particularly preferred embodiment, a mixture of water and ammonia is used. In the system shown in Figure 1, the working current has the same composition from point 13 to point 19. Starting the discussion of the system of Figure 1 at the output of the turbine T, the current at point 34 is referred to as the current rich in expanded gas spent. This current is considered "rich" in the lowest boiling component. It is at a low pressure, and will be mixed with a leaner absorbent stream, which has the parameters as point 12, to produce the working current of an intermediate composition having the parameters as in point 13. The current at the point 12 is considered "lean" in the component of lower boiling point. At any given temperature, the working current (of an intermediate composition) at point 13, can be condensed at a lower pressure than the richest current at point 34. This allows more energy to be extracted from the turbine T, and increases the efficiency of the process. The working current at point 13 is partially condensed. This current enters the heat exchanger HE-2, where it is cooled and leaves the heat exchanger HE-2 having the parameters as in point 29. It is still partially, and not completely, condensed. Now the current enters the heat exchanger HE-1, where it is cooled by the current 23-24 of cooling water, and in this way it completely condenses, obtaining the parameters as in point 14. The current of work that has the parameters as in point 14 are then pumped to a higher pressure, obtaining the parameters as in point 21. The working current at point 21 then enters the HE-2 heat exchanger, where it is heated in a recuperative way by means of the working current in points 13-29 (see above), up to a point that has the parameters as point 15. The working current that has the parameters as in point 15 , enter heat exchanger HE-3, where it is heated and obtain the parameters as in point 16. In a typical design, point 16 may be precisely at the boiling point, but UNCLE needs to be like that. The working current in point 16 is divided into two subcurrents; the first work sub-current 117, and the second work sub-current 118. The first work sub-current, which has the parameters as in point 117, is sent to the HE-5 heat exchanger, leaving it with the parameters as in point 17 It is heated by the external heat source, in the current 25-26. The other subcurrent, the second working substream 118, enters the HE-4 heat exchanger, where it is heated in a recuperative manner, obtaining the parameters as in point 18. The two working substreams 17 and 18, which have left of the heat exchangers HE-4 and HE-5, combine to form a heated gas working stream, which has the parameters as in point 19. This current is in a state of partial vaporization, or possibly complete. In the preferred embodiment, the point 19 is only partially vaporized. The working current at point 19 has the same intermediate composition that was produced at point 13, completely condensed at point 14, pumped at a high pressure at point 21, and preheated to point 15 and up to point 16. It enters the separator S. There, it separates into a saturated rich vapor, called "heated gas rich current", and has the parameters as in point 30, and a lean saturated liquid called "lean current", and that has the parameters as in point 7. The lean current (saturated liquid) at point 7, enters the HE-4 heat exchanger, where it cools while heating the working current 118-18 (see above). The lean current at point 9 leaves the heat exchanger HE-4 with the parameters as in point 8. It will drown up to a suitably selected pressure, obtaining the parameters as in point 9. Returning now to point 30, the Current rich in heated gas (saturated steam) exits the separator S. This current enters turbine T, where it expands at lower pressures, providing useful mechanical energy to the turbine T, used to generate electricity. A partially expanded stream having the parameters such as point 32 from turbine T, is extracted at an intermediate pressure (approximately the pressure as in point 9), and this extracted stream 32 (also referred to as a "second portion" of a rich current partially expanded, the "first portion" expanding further), mixes with the lean current at point 9 to produce a combined current having the parameters as in point 10. The lean current having the parameters as in point 9, serves as an absorbing current for the extracted current 32. The resulting current (lean current and second portion), which has the parameters as in point 10, enters the heat exchanger HE-3, where it cools, while it heats the working current 15-16, up to a point that has the parameters as in point 11. The current that has the parameters as in point 11 is then drowned until the pressure of point 34, obtaining the parameters as point 12. Returning to the turbine T, not all the inward flow of the turbine was extracted at point 32 in a partially expanded state. The rest, referred to as the first portion, expands to a suitably selected low pressure, and leaves the turbine T at point 34. The cycle is closed. In the embodiment shown in Figure 1, the extraction at point 32 has the same composition as the currents at points 30 and 34. In the embodiment shown in Figure 2, the turbine is shown as the first turbine stage Tl and the second turbine stage T-2, leaving the partially expanded rich stream from the highest pressure stage Tl of the turbine at point 31. In Table 2 the conditions in the numbered points shown in Figure 2 are presented. Typical output from the system of Figure 2 is presented in Table 6. Referring to Figure 2, the rich stream partially expanded from the first turbine stage Tl is divided into a first portion at 33, which further expands at the turbine stage at a lower pressure T-2, and a second portion at 32 which is combined with the current lean at 9. The partially expanded rich stream enters separator S-2, where it is separated into a portion of vapor and a liquid portion. The composition of the second portion at 32 can be selected in order to optimize its effectiveness when mixed with the current at point 9. The separator S-2 allows current 32 to be as lean as the liquid saturated at the pressure and temperature obtained in separator S-2; in that case, stream 33 would be a saturated vapor under the conditions obtained in separator S-2. By choosing the amount of mixture in stream 133, the amount of saturated liquid and saturated vapor in stream 32 can be varied. Referring to Figure 3, this embodiment differs from the embodiment of Figure 1, in that the HE-4 heat exchanger has been omitted, and there is no extraction of a partially expanded stream from the turbine stage. In the embodiment of Figure 3, the hot stream leaving the separator S is admitted directly into the HE-3 heat exchanger. Table 3 shows the conditions in the numbered points shown in Figure 3. Table 7 shows a typical output from the system. _ Referring to Figure 4, this embodiment differs from the embodiment of Figure 3 in that the HE-2 heat exchanger is omitted. Table 4 shows the conditions in the numbered points shown in Figure 4. Table 8 shows a typical output from the system. Although the omission of the heat exchanger HE-2 reduces the efficiency of the process, it can be economically recommendable in circumstances in which the given increased energy does not pay for the cost of the heat exchanger. In general, conventional equipment can be used in carrying out the method of this invention. Accordingly, equipment such as heat exchangers, tanks, pumps, turbines, valves, and connections of a type used in a typical Rankine cycle may be employed in the embodiment of the method of this invention. In the described embodiments of the invention, the working fluid is expanded to drive a turbine of a conventional type. However, the expansion of the working fluid from a charged high pressure level to a low pressure level spent to release energy can be effected by any suitable conventional element known to those skilled in the art. The energy thus released can be stored or used in accordance with any of a number of conventional methods known to those skilled in the art. The separators of the described embodiments can be conventionally used gravity separators, such as conventional evaporation tanks. Any conventional apparatus used to form two or more streams having different compositions from a single stream can be used to form the lean stream and the enriched stream from the working fluid stream. The condenser can be any type of known heat rejection device. For example, the condenser may have the form of a heat exchanger, such as a water-cooled system, or another type of condensing device. Different types of heat sources can be used to drive the cycle of this invention.

Table 1 P Kg / cm X H BTU / 0.4536 kg. G / G30 Flow kg / hr. Phase 7 22.76 .5156 94.80 82.29 .5978 125,546.50 Saturated liquid 8 21.36 .5156 76.39 44.55 .5978 125,546.50 Liquid 2.2 ° C 9 14.99 .5156 76.38 44.55 .5978 125,546.50 Wet .9997 14.99 .5533 76.39 90.30 .6513 136,782.62 Wet .9191 11 13.59 .5533 37.67 -29.79 .6513 136,782.62 Liquid 11.66 ° C 12 5.98 .5533 37.41 -29.79 .6513 136,782.62 Wet .9987 13 5.98 .7000 37.67 174.41 1 210.024.05 Wet .6651 14 5.91 .7000 22.44 -38.12 1 210.024.05 Saturated Liquid 24.51 .7000 34.90 -13.08 1 210.024.05 Liquid 22.77 ° C 16 23.46 .7000 73.61 65.13 1 210.024.05 Saturated Liquid 117 23.46 .7000 73.61 65.13 .8955 210.024.05 Saturated Liquid 17 22.76 .7000 95.21 302.92 .8955 188,072.08 Wet .5946 118 23.46 .7000 73.61 65.13 .1045 210.024.05 Saturated Liquid 18 22.76 .7000 92.10 281.00 .1045 21,951.97 Wet .6254 19 22.76 .7000 94.88 300.63 1 210.024.05 Humid .5978 21 24.86 .7000 22.86 -36.76 1 210.024.05 Liquid 35.55 ° C 29 5.94 .7000 35.00 150.73 1 210.024.05 Wet .6984 22.76 .9740 94.88 625.10 .4022 84,477.55 Saturated Steam 32 14.99 .9740 76.76 601.53 .0535 11.236.12 Wet .0194 34 5.98 .9740 40.32 555.75 .3487 73.241.43 Wet .0467 23 • water 17.99 32.40 9.8669 2.072,280.20 24 • water 28.63 51.54 9.8669 2.072,280.20 25 • water 97.99 176.40 5.4766 1, 150.216.20 26 • water 76.39 137.52 5.4766 1, 150.216.20 Table 2 P Kg / c ¿X H BTU / 0.4536 kg. G / G30 Flow kg / hr. Phase 7 22.76 .5156 94.80 82.29 .5978 125,546.50 Saturated liquid 8 21.36 .5156 76.39 44.55 .5978 125,546.50 Liquid 2.2 ° C 9 14.99 .5156 76.37 44.55 .5978 125,546.50 Humid .9997 14.99 .5523 76.39 89.23 .6570 137,992.37 Wet .921 11 13.59 .5523 37.62 -29.96 .6570 137,992.37 Liquid 11.66 ° C 12 5.98 .5523 37.51 -29.96 .6570 137,992.37 Wet .9992 13 5.98 .7000 37.62 173.96 1 210.024.05 Wet .6658 14 5.91 .7000 22.44 -38.12 1 210.024.05 Saturated Liquid 24.51 .7000 34.85 -13.18 1 210.024.05 Liquid 22.77 ° C 16 23.46 .7000 73.61 65.13 1 210.024.05 Saturated Liquid 117 23.46 .7000 73.61 65.13 .8955 210.024.05 Saturated Liquid 17 22.76 .7000 95.21 302.92 .8955 188,072.08 Wet .5946 118 23.46 .7000 73.61 65.13 .1045 210.024.05 Saturated Liquid 18 22.76 .7000 92.10 281.00 .1045 21, 951.97 Wet .6254 19 22.76 .7000 94.88 300.63 1 210.024.05 Humid .5978 21 24.86 .7000 22.86 -36.76 1 210.024.05 Liquid 35.55 ° C 29 5.94 .7000 34.97 150.38 1 210.024.05 Wet .6989 22.76 .9740 94.88 625.10 .4022 84,477.55 Saturated Steam 31 15.02 .9740 77.00 602.12 .4022 84,477.55 Wet .0189 32 15.02 .9224 77.00 539.93 .0593 12.445.42 Wet .1285 33 15.02 .9829 77.00 612.87 .3430 72,031.68 Saturated Steam 34 5.98 .9829 39.98 564.60 .3430 72,031.68 Wet .0294 15.02 .5119 77.00 45.44 .0076 1, 599.84 Saturated Liquid 23 • water 17.99 32.40 9.8666 2,072,213.00 24 • water 28.60 51.50 9.8666 2,072,213.00 25 • water 97.99 176.40 5.4766 1, 150.216.20 26 • water 76.39 137.52 5.4766 1, 150.216.20 Table 3 P Kg / cm X H BTU / 0.4536 kg. G / G30 Flow kg / hr. Phase 20.43 .4826 95.21 80.72 .6506 133,577.94 Saturated liquid 11 19.03 .4826 42.78 -23.56 .6506 133,577.94 Liquid 31.66 ° C 12 5.27 .4826 42.81 -23.56 .6506 133,577.94 Wet .9994 13 5.27 .6527 42.78 180.50 205,321.13 Wet .6669 14 5.20 .6527 22.44 -47.40 205.321.13 Saturated liquid 22.18 .6527 39.99 -12.43 205.321.13 Liquid 17.77 ° C 16 21.13 .6527 73.61 55.41 205.321.13 Saturated liquid 17 20.43 .6527 95.21 273.22 205.321.13 Wet .6506 21 22.53 .6527 22.79 -46.18 205.321.13 Liquid 36.10 ° C 29 5.23 .6527 38.24 146.74 205.321.13 Wet .7104 20.43 .9693 95.21 631.64 .3494 71,743.19 Saturated Steam 34 5.27 .9693 42.54 560.44 .3494 71,743.19 Wet .0474 23 • water 17.99 32.40 8.1318 1, 669,634.40 24 • water 31.25 56.27 8.1318 1,669,634.40 25 • water 97.99 176.40 5.6020 1,150,216.20 26 • water 76.39 137.52 5.6020 1,150.216.20 Table 4 P Kg / cm H BTU / 0.453. kg. G / G30 Flow kg / hr. Phase 15.00 .4059 95.21 80.05 .7420 179,413.76 Saturated liquid 11 13.60 .4059 25.47 -55.30 .7420 179,413.76 Liquid 47.77 ° C 12 3.67 .4059 25.64 -55.30 .7420 179,413.76 Liquid 0 ° C 29 3.67 .5480 40.25 106.44 241,805.08 Wet .7825 14 3.63 .5480 22.44 -60.06 241,805.08 Saturated liquid 21 17.10 .5480 22.68 -59.16 241, 805.08 Liquid 36.66 ° C 16 15.70 .5480 73.61 41.26 241, 805.08 Saturated liquid 17 15.00 .5480 95.21 226.20 241, 805.08 Wet .742 15.00 .9567 95.21 646.49 .2580 62.390.86 Saturated steam 34 3.67 .9567 45.65 571.55 .2580 62,390.86 Wet .0473 23 • water 17.99 32.40 5.7346 1,386,663.30 24 • water 34.12 61.43 5.7346 1,386,663.30 25 • water 97.99 176.40 4.7568 1,150,216.20 26 • water 76.39 137.52 4.7568 1, 150.216.20 Table 5 Performance Summary KCS34 Case 1 Heat at: 28893.87 kW 237.78 BTU / lb Rejected heat 25638.63 kW 210.99 BTU / lb S Turbine enthalpy falls 3420.86 kW 28.15 BTU / lb Turbine work 3184.82 kW 26.21 BTU / lb Power pump? H 1.36, power 175.97 kW 1.45 BTU / lb Power + coolant, pump power 364.36 kW 3.00 BTU / lb Net work 2820.46 kW 23.21 BTU / lb Gross production 3184.82 kWe Cycle production 3008.85 kWe Net production 2820.46 kWe Net thermal efficiency 9.76% Limit of the second law 17.56% Efficiency of the second law 55.58% Specific consumption of brine 407.80 kg / kW hr Production of specific energy 1.11 Watt hr / 0.4536 kg Table 6 Performance summary KCS34 Case 2 Turbine mass flow 58.34 kg / s 463016 lb / hr Volume flow Pt 30 4044.45 1 / s 514182 ftA3 / hr Heat at: 28893.87 kW 212.93 BTU / lb Rejected heat 25578.48 kW 188.50 BTU / lb S Turbine enthalpy drops 3500.33 kW 25.80 BTU / lb Turbine work 3258.81 kW 24.02 BTU / lb Power pump? H 1.36, power 196.51 kW 1.45 BTU / lb Power + coolant, pump power 408.52 kW 3.01 BTU / lb Net work 2850.29 kW 21.00 BTU / lb Gross production 3258.81 kWe Cycle production 3062.30 kWe Net production 2850.29 kWe Net thermal efficiency 9.86% Limit of the second law 17.74% Efficiency of the second law 55.60% Specific consumption of brine 403.54 kg / kW hr Production of specific energy 1.12 Watt hr / 0.4536 kg Table 7 Performance summary KCS34 Case 3 Mass flow of the turbine 57.03 kg / s 452648 lb / hr Volume flow Pt 30 4474.71 I / s 568882 ft? 3 / hr Heat at: 28893.87 kW 217.81 BTU / lb Rejected heat 25754.18 kW 194.14 BTU / lb S Turbine enthalpy falls 3300.55 kW 24.88 BTU / lb Turbine work 3072.82 kW 23.16 BTU / lb Power pump? H 1.21, power 170.92 kW 1.29 BTU / lb Power + coolant, pump power 341.75 kW 2.58 BTU / lb Net work 2731.07 kW 20.59 BTU / lb Gross production 3072.82 kWe Production of the cycle 2901.89 kWe Net production 2731.07 kWe Net thermal efficiency 9.45% Limit of the second law 17.39% Efficiency of the second law 54.34% Specific consumption of brine 421.15 kg / kW hr Production of specific energy 1.08 Watt hr / 0.4536 kg Heat to the steam boiler 15851.00 kW 577.22 BTU / lb Rejected heat 10736.96 kW 390.99 BTU / lb Table 8 Performance summary KCS34 Case 4 Turbine mass flow 67.17 kg / s 533080 lb / hr Volume flow Pt 30 7407.64 1 / s 941754 fT3. hr Heat at: 28893.87 kW 184.94 BTU / lb Rejected heat 26012.25 kW 166.50 BTU / lb S Turbine enthalpy drops 3020.89 kW 19.34 BTU / lb Turbine work 2812.45 kW 18.00 BTU / lb Power pump? H .89, power 147.99 kW 0.95 BTU / lb Power + coolant, pump power 289.86 kW 1.86 BTU / lb Net work 2522.59 kW 16.15 BTU / lb Gross production 2812.45 kWe Cycle production 2664.46 kWe Net production 2522.59 kWe Net thermal efficiency 8.73% Limit of the second law 17.02% Efficiency of the second law 51.29% Specific consumption of brine 455.96 kg / kW hr Production of specific energy 0.99 Watt hr / 0.4536 kg

Claims (24)

1. A method for implementing a thermodynamic site, which comprises: heating a working stream that includes a low boiling point component and a higher boiling point component, with an external heat source, to provide a gaseous work stream heated, separating the gaseous work stream heated in a first separator, to provide a heated gaseous rich stream having relatively more of the low boiling component, and a lean stream having relatively less of the low boiling component, expanding the gaseous rich stream heated to transform the energy of the stream to a usable form, and to provide a rich expanded spent stream, and to combine the lean stream and the spent rich stream expanded to provide the working stream.

The method of claim 1, wherein, after combining and before heating with the external heat source, the working stream is condensed by transferring heat to a low temperature source in a first heat exchanger , and the working current is subsequently pumped up to a higher pressure.

3. The method of claim 1, wherein the expansion takes place in a first expansion passage and in a second expansion passage, the heated gaseous rich stream partially expanding to provide a rich partially expanded stream in the first expansion passage, which it further comprises dividing the partially expanded rich stream into a first portion and a second portion, wherein the first portion expands to provide the spent rich stream expanded in the second expansion passage, and which further comprises combining the second portion. with the lean current before combining the lean current and the expanded exhausted rich current.

The method of claim 2, which further comprises transferring, in a second heat exchanger, the heat from the working stream, before the working current is condensed, to the working stream after it has been pumped the working current to the highest pressure and before heating with the external heat source.

The method of claim 2, which further comprises transferring, in a third heat exchanger, the heat from the lean stream to the working stream after the working stream has been pumped at the highest pressure and before of the heating with the external heat source.

The method of claim 4, which further comprises transferring, in a third heat exchanger, the heat from the lean stream to the working stream after the working current has received the heat in the second heat exchanger and before heating with the external heat source.

The method of claim 2, which further comprises: dividing the working current, after pumping and before heating with the external heat source, into a first working sub-current and a second working sub-current, and wherein heating with the external heat source involves heating the first working sub-current with the external heat source to provide a first heated work sub-current, and then combining this first heated work sub-current with the second work sub-current to provide the heated gas work.

The method of claim 7, which further comprises transferring, in a fourth heat exchanger, the heat from the lean stream to the second work substream.

9. The method of claim 1, wherein the heating with the external source of heat is presented in a fifth heat exchanger.

The method of claim 3, wherein the division includes separating the partially expanded rich stream into a vapor portion and a liquid portion, the first portion including at least some of the vapor portion, and including the second portion to the vapor portion. liquid portion.

11. The method of claim 10, which further comprises combining some of the vapor portion with the liquid portion to provide the second portion.

The method of claim 3, which further comprises transferring, in a heat exchanger, the heat from the lean stream with the second portion to the working stream before the working stream has been heated with the source of external heat.

13. An apparatus for implementing a thermodynamic cycle, which comprises: a heater that heats a work stream that includes a low boiling point component and a higher boiling point component, with an external heat source, to provide a heated gas working stream, a first separator connected to receive the heated gaseous working stream, and to produce a heated gaseous rich stream having relatively more of the low boiling component, and a lean stream having relatively less of the component of low boiling point, an expander which is connected to receive the heated gaseous rich stream and transformed the current energy to a usable form, and to produce a rich expanded spent stream, and a first current mixer which is connected to combine the lean current and the expanded exhausted rich current, and produce the working current , connecting the output of the current mixer to the heater inlet.

The apparatus of claim 13, which further comprises a first heat exchanger and a pump that are connected between the first current mixer and the heater, condensing the first heat exchanger to the working stream by heat transfer to a source of low temperature, and pump the pump subsequently the working current to a higher pressure.

The apparatus of claim 13, wherein the expander includes a first expansion stage and a second expansion stage, the first expansion stage connecting to receive the heated gaseous rich stream, and to produce a rich partially expanded stream, the which further comprises a current divider that is connected to receive the rich, partially expanded stream, and divide it into a first portion and a second portion, wherein the second stage is connected to receive the first portion, and expands from the first portion to providing the expanded spent spent stream, and which further comprises a second current mixer which is connected to combine the second portion with the lean stream before the lean stream is combined with the spent rich stream expanded in the first stream mixer.

16. The apparatus of claim 14, which further comprises a second heat exchanger connected to transfer heat from the working current, before the working current is condensed, to the working current after the pump has been pumped. working current at the highest pressure in the pump, and before heating with the external heat source in the heater.

The apparatus of claim 14, which further comprises a third heat exchanger connected to transfer heat from the lean stream to the working stream, after which the working current has been pumped to the highest pressure in the pump , and before heating with the external heat source in the heater.

The apparatus of claim 16, which further comprises a third heat exchanger connected to transfer heat from the lean stream to the working stream, after the working current has received the heat in the second heat exchanger, and before heating with the external heat source in the heater.

19. The apparatus of claim 14, which further comprises: a current divider connected to divide the working current, after pumping in the pump, and before heating with the external heat source in the heater, in a first working sub-current and a second working sub-current, the heater heating the first working sub-current to provide a first working sub-current heated, and a third connected current mixer for combining the first heated working sub-current with the second working sub-current, to provide the heated gas working stream.

20. The apparatus of claim 19, further comprising a fourth heat exchanger connected to transfer heat from the lean stream to the second work substream.

21. The apparatus of claim 13, wherein the heater is a fifth heat exchanger.

22. The apparatus of claim 15, wherein the current divider includes a second separator that is connected to receive the rich, partially expanded stream, and to separate it into a vapor portion and a liquid portion, the first portion including at least one portion. of the vapor portion, and including the second portion to the liquid portion.

23. The apparatus of claim 22, wherein the current divider includes a fourth connected current mixer to combine some of the vapor portion from the second separator with the liquid portion from the second separator to provide the second portion. The apparatus of claim 15, which further comprises a heat exchanger connected to transfer heat from the lean stream with the second portion to the working stream, before the working current has been heated with the heat source external in the heater.