DE3327752A1 - Method and device for increasing the efficiency of turbine processes - Google Patents

Abstract

The present invention is intended to serve for at least partially exploiting the exergy of a heat accumulator normally at a technically unusable, high temperature level T1. For this purpose it is proposed to use an "exergy-receiving compressor", which utilises the temperature difference between the high temperature T1 and a technically usable temperature level T2, in order to raise heat from a low temperature level T3 likewise to a technically usable level T2. This is achieved, for example, by suitable design using a system similar to the principle of the absorption refrigerating machine. The sorption cycle, comprising expeller (1), restrictor (13), absorber (9), pump (11) and where necessary a heat exchanger system (12, 14) at functions in this as "exergy-receiving compressor". The efficiency of the conversion of heat into mechanical energy can be improved by this system. <IMAGE>

Description

Method and device to increase the effectiveness

Degree of Turbine Processes The present invention relates to a Method according to the preamble of the main claim and devices for implementation of the procedure. According to the current state of the art, it is so that the primary heat often occurs at a very high temperature in a turbine process (e.g. in combustion chambers or for receivers of concentrated sunlight), but for reasons of material this high temperature cannot be used directly as there is no moving one mechanical components for such high temperatures and long-term use. The on The amount of heat generated at high temperatures must therefore lose all of the exergy be cooled to a technically usable level before a heat and power process can be connected downstream. This leads to a loss of efficiency in the processes and accordingly to a poor utilization of the actually available exergy.

According to the state of the art, e.g. from the "Brockhaus der Naturwissenschaften und der Technik ", 7th edition, F.A. Brockhaus, Wiesbaden 1972, page 380, 381 a Absorption chiller known, which reverses the function also as a heat pump is to be understood. This heat pump based on the absorption principle is powered by an absorption cycle operated, which maintains a pressure difference due to a temperature difference and thus works as a compressor. So far there have been Absorption chillers also operated as heat pumps in the low temperature range, however, are applications not known for particularly high temperatures.

A wave energy exchanger is also known from US Pat. No. 2,399,394, which can be operated as a heat transformer between two gases. A Such a wave energy exchanger can be called an "exergy-maintaining compressor", because it enables an enthalpy exchange between two gases. Such a wave energy exchanger can be operated in such a way that it results in a hot gas at a medium temperature level cools and its exergy is used to generate another gas from a low one Raise the temperature level to a medium one. However, this usage has been not yet considered.

The object of the present invention is to improve the efficiency of turbine processes or the like, in which the primary heat on a technically unusable high temperature level is coupled. The present invention is based on the realization that, contrary to the usual practice up to now, it is possible is, part of the amount of heat stored in the high temperature level To exploit exergy to additionally use a medium from low temperature to a technical one to raise the usable temperature level.

A method according to the main claim is used to solve this problem suggested. For this purpose, an "exergy-maintaining compressor" is to be operated in the circuit which is the temperature difference between primary temperature and technical exploits usable temperature, to add a medium from a lower temperature to technically usable temperature. Instead of just Cooling down, during which all exergy is lost, can be achieved with the use of a Exergy-maintaining compressor "a part of the exergy can be used. In the claims 2 and 8 show various basic options for executing exergy-preserving Compressors ". According to claim 2, there is a possibility the exergy-preserving compression in the known application of a thermal Compressor based on the principle of an absorption process. In this case the thermal compressor used to drive a heat pump, and its two temperature levels are considerably higher than in the known applications. Otherwise it is However, the functionality is analogous to that known from the prior art. The primary heat is fed to an expeller in which a gaseous first medium passes through Energy supply from a liquid or solid, second medium in which it is dissolved or was bound, is driven out.

The expelled first medium is in a condenser on a technically usable temperature level condenses, the condensed first medium is based on the principle of a heat pump after passing through a recuperative heat exchanger relaxed in a throttle valve or a pump and then takes in one Evaporator energy at a low temperature level, whereupon in the recuperative heat exchanger the previously withdrawn heat is supplied again. Then the first medium led to an absorber, in which it is again in the second liquid or solid Medium is dissolved or bound. The temperature in the absorber is also at one technically usable level, so that the heat of absorption occurring there is used can be. The "rich" solution of both media will be from a pump again led to the expeller, while the "poor" solution via a throttle valve and optionally flows into the absorber via a recuperative heat exchanger system. In the case of a solid medium, it is transported via a lock system. The one in the condenser and the heat generated in the absorber is used in subsequent heat and power processes utilized.

The proposed system has the advantage that the absorption process the temperature difference between the expeller and absorber at least partially Utilizes conversion into compression energy. At least this part of the exergy can be used in the connected heat pump process and thus increases the Efficiency.

In claim 3 it is proposed in a special embodiment of the invention, as a supply for the heat pump, part of the waste heat from the heat and power processes to use, which is also a favorable exploitation of the possibility of increasing the Efficiency is.

In the fourth claim are pairs of substances for the high-temperature sorption process suggested, namely water and hygroscopic media such as salts and hydroxides.

Alternatively, claim 5 provides other suitable pairs of substances, namely C02 or SO2 and metal oxides, which then bind carbonates or Sulphates or sulphites are formed.

In claims 6, 7 and 8, devices are used to carry out: of the method proposed, which will be explained in more detail below with reference to the drawing explained.

In claims 9 and 10 an alternative version travel and an associated device for carrying out this method is proposed. In this case, the "exergy-maintaining compressor" is not passed through a sorption cycle but realized by a wave energy exchanger. Such wave energy exchangers are known as heat transformers for various applications (e.g. Croes, N .: "The Principle of the Pressure-Wave-M: ichine as Used for Charging Diesel Engines", Proc. of the 11th International Symposium on Shock Tubes and Waves, Seattle, Washington, July 11-14, 1977). In this case it is particularly proposed that the wave energy exchanger is operated just so that the final temperature and the final pressure of the driving and the gas to be driven are the same, so that the two outputs are connected can. In addition, the wave energy exchanger is at a high temperature located driving gas and uses the temperature difference between the initial temperature and the technically usable temperature, gas of lower Also to raise the temperature to the technically usable level. The corresponding Apparatus according to claim 10 is also explained in more detail with reference to the drawing.

The technical background of the invention and what is essential to the invention Parts are described in the drawing using exemplary embodiments. Show it Fig. 1 shows an embodiment of the invention with a sorption circuit, Fig. 2 a Embodiment of the invention with a wave energy exchanger and FIG. 3 likewise another embodiment of the invention with a wave energy exchanger.

In Fig. 1 is an embodiment according to the invention with a sorption circuit shown. This embodiment is basically similar to an absorption refrigeration machine, but with a different interpretation, the new purpose according to the invention is adapted. In an off driver 1, the amount of heat is at a high temperature T1 Q1 coupled. This creates a liquid medium in which a gaseous Medium was bound or dissolved, expelled the gaseous medium.

It gets into a condenser 2, where it gets its heat on a technically Usable temperature level T2 emits uiid cooled to temperature T4 will. The temperature T4 is greater than or equal to the temperature T3 of the 3 of the capacitor Then the liquid created in the condenser is used relaxed in a throttle valve 5, whereby it is further reduced to the temperature T5 cools down. This temperature T5 can be lower than the ambient temperature 5. This allows heat from the environment in an evaporator 6 via heat exchange surfaces 7 are supplied at temperature T3. Here, of course, can also be cheap available low-temperature heat can be coupled in. The temperature of the medium increases as a result to the temperature T6, which is less than or equal to T3.

Through a system of recuperative heat exchangers 4, 8 through which the Liquid before the throttle valve 5 heat is withdrawn, which is behind the evaporator 6 is poured in again, the yield can be reduced by coupling the heat in the evaporator 6 can be increased. Then the gas reaches a temperature T7, which is when using of recuperative heat exchangers is less than or equal to T4, in an absorber 9. In This absorber 9 is the gas again in the liquid medium of the sorption circuit dissolved or bound, the released heat via heat exchange surfaces 10 is discharged. The absorber is on one technically usable temperature level T2. The "rich" solution is returned by a pump 11 transported into the expeller while at the same time the "poor" solution from the expeller 1 reaches the absorber 9 via a throttle valve 13. If technically possible, can also have a recuperative heat exchanger system 12, 14 behind in this circuit the pump 11 or before the throttle valve 13 are provided. With this arrangement the sorption cycle acts like a compressor, which depends on the temperature difference is driven between T1 and T2. The decoupled in the absorber 9 at the temperature T2 Heat can be used in a downstream heat and power process 16, 18, 19. Likewise, the heat coupled out in the condenser 2 can be at temperature T'2 in one downstream power-heat coupling process 15, 18, 19 are used, for example to drive a generator 17. There is a corresponding amount of waste heat Q2, A small part of which can also be used, for example, to be used on the evaporator 6 as an additional Heat Q3 to be coupled. In principle, depending on the technical possibilities also the heat content of the expelled gas, the exergy of which is otherwise partially lost would be recuperated. With a (indicated by dashed lines) heat exchanger 20, in which the gas is cooled isobarically, heat could be extracted and (as also dashed indicated) can also be used to preheat the "poor" solution.

Fig. 2 shows an embodiment of the invention with a wave energy exchanger 22. In a heater 21, an amount of heat Q1 is supplied to a gas that is produced by a medium temperature level T5 is heated to the high temperature level T1. This gas heated to T1 is fed to the wave energy exchanger 22. The wave energy exchanger acts as a heat transformer, so the temperature of the driving Gas is lowered from T1 to T2, while at the same time a driven gas, which fed to the wave energy exchanger on the other hand, from the low one Temperature T3 is also raised to temperature T2. The whole now The amount of gas at temperature T2 is passed through a heat exchanger 23, in which the heat is decoupled and a downstream heat and power process 24, 25, 26 is fed.

Behind the heat exchanger 23 is the gas flow, which is now the temperature T4, with about a third of the flow through a compressor 27 is passed back to the heater 21 while increasing its temperature to T5 the other two thirds with extraction of power, for example in a turbine 28, to be expanded. This lowers the temperature so much that in one Heat exchanger 30 ambient heat or low-temperature heat at temperature T3 can be fed. This branch of the circuit then becomes the low temperature input of the wave energy exchanger 22 is performed. The turbine 28 can be a generator 29 drive and / or serve to drive the compressor 27. Also in this embodiment it is possible again to use part of the waste heat Q2 from the heat and power process 24, 25, 26 to be fed back to the heat exchanger 30 as the amount of heat Q3.

In Fig. 3 is a further, particularly simple embodiment of the invention shown. In a heater 31, an amount of heat Q1 becomes a gas supplied, the temperature of which increases from T6 to the high value T1. This on T1 heated gas is fed to a wave energy exchanger 32.

This acts as a heat transformer, so that the temperature of the driving Gas is lowered from T1 to T2, while at the same time a driven gas, which is fed to the wave energy exchanger 32 on the other hand from the low Temperature T3 is also raised to temperature T2. The whole now The amount of gas at temperature T2 is divided into two substreams of approximately the same size divided. A partial flow is fed to a turbine 33, where the gas is cooled down relaxed on T4.

Subsequently, the amount of heat Q2 is given to him by the heat exchanger 35 withdrawn. The gas cools down from T4 to T5. It is then through the compressor 38 compressed and thereby brought to the pressure prevailing in the heater 31, at its Entry it has the temperature T6. The other partial flow comes with the temperature T2 into the turbine 36, the gas cooling down to the temperature T3 with which it is then fed back to the wave energy exchanger 32.

The advantage of the invention is to be based on FIG. 1 with a numerical example explained.

Let: the temperature T1 in the expeller 1800 K be the temperature T2 in the absorber 800 K the low temperature T3 is about 300 K.

1/2 of the amount of heat Q1 supplied in the expeller will be used for the Desorption and 1/2 used to warm up the media.

The whole temperature difference between 1800 K and 300 K could be used the theoretical efficiency would be 1800 - 300 = 0.833, i.e. it could a maximum of 0.833x Q1 can be converted into mechanical energy.

Could - as previously generally - only the difference between 800 K and 300 K are used, the theoretical efficiency would be 7 800 - 300 = 0.625, i.e. a maximum of 0.625 x Q1 could be converted into mechanical energy.

The following happens in the proposed system: 1/2 Q1 goes into the temperature increase of the media and can only be used after cooling down to 800 K. will. For this half the theoretical efficiency is # 800 - 300 = 0.625.

In this way, therefore, a maximum of 0.312XQ1 in mechanical energy converted.

However, the other part of Q1 can be better used: This part the sorption cycle converts with a theoretical efficiency of n 1800 - 800 = 0.555 in compression energy. This results in a maximum of 0.277xQ1 in mechanical terms Energy.

This mechanical energy is based on the principle of the absorption heat pump used to raise a medium from T3 = 300 K to T2 = 800 K. The efficiency this process is 80-300 = 1.6.

I The result is an amount of heat of 0.444xQ1, which in the absorber is at 800 K. In addition, there is the unconverted heat loss from the Sorption circle from 0.222 X Q1 also to 800 K. All in all, this is in the absorber an amount of heat from 0.666XQ1 to 800K. This can again with r) 8CO - 300 = 0.625 can be used, i.e.

a maximum of 0.416xQ1 can still be converted into mechanical energy there will. For this half of Q1, X 1800 - 300 is actually reached.

In total, the process produces a maximum of 0.416SQ1 + 0.312xQ1 = 0.728xQ1 of mechanical energy, i.e. the theoretical efficiency is # total. 0.728.

Depending on the division of Q1, this value can result in a temperature increase move the media and desorption; however, it is always between 1800 and 300 and X 800 - 300.

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Claims (10)

Method and device for increasing the efficiency of turbine processes Claims Oi Method for increasing the efficiency of turbine processes and the like, in which the primary heat supply (Q1) is at such a high temperature level occurs that direct utilization is not technically possible, g e k e n n z One of the following features: The process is carried out by an "exergy-conserving Compressor "driven, this compressor the temperature difference between Primary temperature (T1) and technically usable temperature (T 2 "exploited to additionally a medium from a lower temperature (T3) to a technically usable temperature (T2) to be raised. 2. The method of claim 1, wherein the "exergy-maintaining compressor" is a thermal compressor based on the principle of an absorption process, g e k e n n -z e i c h n e t d u r c h the following features: a) The primary heat (Q1) is an expeller (1), in which a gaseous first medium is supplied by energy expelled from a liquid, second medium in which it was dissolved or bound will. b) The expelled first medium is in a condenser (2) condenses to a technically usable temperature level. c) The condensed first medium is according to the principle one Heat pump after passing through a recuperative heat exchanger (4) in a throttle valve (5) relaxes and then takes energy at low levels in an evaporator (6) Temperature level, whereupon the previously withdrawn in the recuperative heat exchanger (8) Heat is supplied again d) The first medium then becomes an absorber (9) in which it is again dissolved or bound in the second liquid medium will. The temperature in the absorber (9) is also technically usable Level, so that the absorption heat generated there can be used. e) The "rich" solution of both media is returned by a pump (11) led to the expeller (1), while the "poor" solution via a throttle valve (13) and optionally via a recuperative heat exchanger system (12, 14) into the absorber (9) flows. f) The heat generated in the condenser (2) and in the absorber (9) is used in subsequent heat and power processes (15, 16). 3. The method according to claim 2, g e k e n n z e i c h n e t d u r c h the following feature: The heat (3) supplied in the evaporator (7) is part of the Waste heat (Q2ì of the heat-power process (15, 16, 18). 4. The method according to claim 2 or 3, g e k e n n -z e i c h n e t The following feature: As a pair of substances for the high-temperature sorption process water and hygroscopic media (e.g. salts, hydroxides) are used. 5. The method according to any one of claims 1-4, g e k e n n -z e i c h n e t d u r c h the following feature: C02 resp. S02 and metal oxides (in the process of binding, carbonates or sulfates or Sulfitec). 6. Device for performing the method according to one of the claims 1 - 5, g e k e k e n n z e i c h n e t d u r c h the following features: a) It is a cycle (1, 13, 14, 9, 11, 12) for a liquid medium available from an expeller (1), a throttle valve (13), possibly a recuperative heat exchanger system (12, 14), an absorber (9) and a pump (11). b) In the expeller (1) there is an amount of heat (Q1) at a high temperature level can be coupled. c) On the expeller (1) is a line for discharging a through the energy supply of the expelled medium is available. d) The absorber (9) has a device (10) for decoupling Warmth. e) There is another circuit for the expelled medium, consisting of a condenser (2) a recuperative heat exchanger system (4, 8), a throttle valve (5) and an evaporator (7), this cycle at the same time runs through the absorber (9l, the pump (11) and the expeller (1)). f) The capacitor (2) has a device (3) for coupling out Heat available at a technically usable level. g) In the evaporator (6) is a device (7) for coupling Low temperature heat (Q3) available. h) The heat extraction devices present in the condenser (2) and in the absorber (9) (3 or 10) lead to a downstream combined heat and power system (15, 16, 17, 18, 19). 7. Apparatus according to claim 6, g e k e n n z e i c h -n e t d u r c h following feature: The heat coupling device (7) is in the evaporator (6) with de cooling system of the cogeneration process so in connection that a part the waste heat (Q2) can be injected again. 8. Apparatus according to claim 6 or 7, g e k e n n -z e i c h n e The following feature: It is an additional recuperative heat exchanger (20) between the expeller (1) and the capacitor (2), the one with the supply line the "poor" solution to the expeller (1) is in heat exchange. 9. The method according to claim 1, wherein as "exergy-maintaining compressor" a wave energy exchanger (22 or 32) is used, g e k e n n z e i c h n e t d u r c h the following features: a) The wave energy exchanger (22 or 32) is just operated as a heat transformer that the final temperature and the final pressure of the driving and the gas to be driven are the same, so that the two outputs can be connected. b) The wave energy exchanger (22 or 32) is on a high Temperature (T1) located driving gas operated and uses the temperature difference between the initial temperature (T1) and the technically usable temperature (T2) in addition, gas of lower temperature (T3) likewise to the technically usable To raise level (T2). 10. Apparatus for performing the method according to claim 9, g e k e n n n z e i c h n e t d u r c h the following features: a) In one Gas circuit in which a heater (21 or 31) has a high amount of heat (Q1) Temperature level (Tf) is coupled in, a wave energy exchanger (22 resp. 32) available. b) The one occurring at the output of the wave energy exchanger (22 or 32) Heat is used in subsequent combined heat and power processes, with one Division is made into two partial flows, one of which is after force extraction is returned to the heater (21 or 31), while the other, also after force extraction is returned to the "cold" input of the wave energy exchanger (22 or 32). c) The second partial flow has between force decoupling (26, 38) and Wave energy exchanger (22 or 32) has a heat exchanger (28, 39) in which Heat (Q3) can be supplied at a low temperature level.