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Title:
CONDENSATION DEVICE AND METHOD COMPRISING A RAIN CONDENSER
Document Type and Number:
WIPO Patent Application WO/2019/004910
Kind Code:
A1
Abstract:
A condensation device (100) for a thermodynamic cycle adapted to convert a gas composition of a working medium into a liquid composition of said working medium through direct contact condensation, the condensation device comprising: a vessel (10) having an essentially cylindrically shaped side wall (13), a top section (11), a bottom section (12), a liquid composition inlet (14), and a liquid composition outlet (15), the liquid composition inlet (14) being arranged in the top section (11) and the liquid composition outlet (15) being arranged in the bottom section (12) of the vessel (10); a perforated plate (20) arranged in the top section (11) of the vessel (10) to delimit a space (18) in fluid communication with the liquid composition inlet (14), wherein the perforated plate (20) comprises a plurality of holes (24) through which the liquid composition may pass to create a plurality of spray clouds comprising the liquid composition, wherein the vessel further comprises a gas composition inlet (16), wherein the gas composition inlet (16) is arranged slightly below the perforated plate (20) in the side wall (13) of the vessel. Additionally, there is provided a method for converting at least one gas composition of a working medium into a liquid composition of said working medium through a thermodynamic cycle utilising direct contact condensation in such a condensation device and a system for energy production utilising a thermodynamic cycle and a circulating working medium, comprising said condensation device.

Inventors:
MUNUKKA KARI (SE)
Application Number:
PCT/SE2018/050686
Publication Date:
January 03, 2019
Filing Date:
June 26, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CLIMEON AB (SE)
International Classes:
B01D3/00; B01D5/00; F25B1/00; F25B30/02; F25B43/04
Domestic Patent References:
WO2003038362A22003-05-08
WO2016068778A12016-05-06
Foreign References:
CN203323585U2013-12-04
US5983996A1999-11-16
US20150233618A12015-08-20
GB1433893A1976-04-28
CN104265389B2016-03-02
US20100236242A12010-09-23
US4991780A1991-02-12
US7654509B22010-02-02
US8579213B22013-11-12
US20050056711A12005-03-17
GB1357783A1974-06-26
Other References:
"Grundoperationen chemischer Verfahren-stechnik", VAUCK/MULLER
"Perry's Chemical Engineer's Handbook"
MINORU TAKAHASHI: "Study on vapor condensation heat transfer to liquid spray", 7TH INTERNATIONAL CONFERENCE ON NUCLEAR ENGINEERING, 19 April 1999 (1999-04-19)
J.M. MOULT ET AL.: "Single rain tray type condensers", PROCEEDINGS OF THE SOUTH AFRICAN SUGAR TECHNOLOGISTS' ASSOCIATION, June 1979 (1979-06-01)
Attorney, Agent or Firm:
BERGENSTRÅHLE & PARTNERS STOCKHOLM AB (SE)
Download PDF:
Claims:
CLAIMS

1. A condensation device (100) for a thermodynamic cycle adapted to convert a gas composition of a working medium into a liquid composition of said working medium through direct contact condensation, the condensation device comprising:

- a vessel (10) having an essentially cyhndrically shaped side wall (13), a top section (11), a bottom section (12), a liquid composition inlet (14), and a liquid composition outlet (15), the liquid composition inlet (14) being arranged in the top section (11) and the liquid composition outlet (15) being arranged in the bottom section (12) of the vessel (10);

- a perforated plate (20) arranged in the top section (11) of the vessel (10) to delimit a space (18) in fluid communication with the liquid composition inlet (14), wherein the perforated plate (20) comprises a plurahty of holes (24) through which the liquid composition may pass to create a plurality of spray clouds comprising the liquid composition,

characterised in that the vessel further comprises a gas composition inlet (16), wherein the gas composition inlet (16) is arranged slightly below the perforated plate (20) in the side wall (13) of the vessel (10). 2. The condensation device (100) according to claim 1, wherein a centre hne (CL) of the gas composition inlet (16) is arranged at an angle (a) to a tangent to the side wall (13) of the vessel (10) at a point of intersection between the centre line (CL) and the side wall (13).

3. The condensation device (100) according to claim 2, wherein said an- gle (a) is larger than 90°, preferably between 95° and 160°, more preferably between 100° and 140°, most preferably said angle is 115°.

4. The condensation device (100) according to any one of the preceding claims, wherein a centre line (CL) of the gas composition inlet (16) is arranged at an angle (β) relative to the z-axis of the vessel (10).

5. The condensation device (100) according to claim 4, wherein the gas composition inlet (16) is arranged horizontally and wherein said angle (β) is

90°.

6. The condensation device (100) according to claim 4, wherein said angle (β) is less than 90°, preferably up to 15° off a horizontal orientation in an upward direction, preferably said angle (β) is between 75° and 90° relative to the z-axis of the condenser, more preferably said angle is 80°.

7. The condensation device (100) according to any one of the preceding claims, wherein the top section (11) of the vessel (10) is dome-shaped.

8. The condensation device (100) according to any one of the preceding claims, wherein the bottom section (12) of the vessel (10) has a conical shape converging towards the liquid composition outlet (15).

9. The condensation device (100) according to any one of the preceding claims, further comprising a supporting member (21) arranged adjacent the perforated plate (20).

10. The condensation device (100) according to claim 9, wherein the sup- porting member (21) is arranged above the perforated plate (20) and further comprising a porous material arranged between the supporting member (21) and the perforated plate (20).

11. The condensation device (100) according to claim 9 or 10, wherein the supporting member (21) comprises a grating. 12. The condensation device (100) according to any one of the preceding claims, further comprising a vortex breaker (19) arranged in or near the liquid composition outlet (15), the vortex breaker (19) including one or more of radial vanes, baffles, and/or curved plates.

13. The condensation device (100) according to any one of the preceding claims, further comprising a diffuser arranged at the gas composition inlet (16).

14. The condensation device (100) according to any one of the preceding claims, wherein the perforated plate (20) has a perforation percentage in the range of l%-40%, preferably 5%-20%.

15. The condensation device (100) according to any one of the preceding claims, wherein the holes (24) in the perforated plate (20) have a diameter in the range 0.01-5 mm, preferably 0.2-0.8 mm, most preferably 0.4-0.6 mm.

16. A method for converting at least one gas composition of a working medium into a liquid composition of said working medium through a thermodynamic cycle utilising direct contact condensation in a condensation device (100) according to any one of the preceding claims 1-15, comprising the steps:

- feeding the liquid composition of said working medium into a liquid composition inlet (14) above a perforated plate (20) of said condensation device (100) and wherein the liquid composition is let to pass through perforated plate (20) of said condensation device (100), thereby forming a plurality of liq- uid sprays comprising droplets of the liquid composition;

- feeding the gas composition of said working medium into a gas composition inlet (16) of said condensation device (100) such that the gas composition contacts the liquid sprays, wherein said gas composition is absorbed or condenses into a stream of liquid composition (Q);

- collecting the stream of liquid composition (Q) after having absorbed or condensed the gas composition feed into said condensation device (100);

- redirecting a first stream (Ql) of the collected stream of liquid composition (Q) for heat transfer (5) with a cold source (CS), and recirculating the cooled first stream (Ql) to a top section (11) of the condensation device (100); - redirecting a second stream (Q2) of the collected liquid composition (Q) for heat transfer (2) with a hot source (HS), wherein the liquid composition in said second stream (Q2) vaporises into said gas composition; and

- adjusting the flow rate of the liquid composition entering the liquid composition inlet (14) to achieve complete, immediate condensation of the gas composition.

17. The method according to claim 16, further comprising feeding the gas composition tangentially into the condensation device (100) in order to achieve a spiral or swirling trajectory of the gas. 18. The method according to claim 16 or 17, further comprising feeding the gas composition at an angle (β) relative a z-axis of the vessel (10) into the condensation device (100).

19. The method according to any one of claims 16-18, further comprising the step:

- redirecting a portion of the second stream (Q2) of the collected stream of liquid composition (Q) into a third stream (Q3) and passing the third stream (Q3) through the top section of the vessel (10) to be cooled.

20. The method according to claim 19, wherein the third stream (Q3) of the collected stream of liquid composition (Q) is used for cooling other compo- nents in the thermodynamic closed-loop cycle, e.g. a pump (17, 22) or a unit for removal of non-condensable gases (30).

21. The method according to any one of claims 16-20, wherein the first stream (Ql) is adjusted to comprise 80%-99.9% of the collected stream of liquid composition (Q) and the second stream (Q2) is adjusted to comprise 0.1%- 20%, preferably 1%-10%, more preferably 3%-8%, most preferably 4%-5%, of the collected stream of liquid composition (Q).

22. The method according to any one of claims 16-21, used for ideally complete absorption or condensation of a working medium in a Rankine cycle, including Organic Rankine Cycles, Kalina cycle, Carbon Carrier cycle and other thermodynamic cycles for energy production, and heat pumps, wherein said working medium is selected from the group consisting of water, hydrocarbons such as methanol and ethanol and isopropanol, ketones such as acetone and MEK, toluene, paraffin, amines or ammonia, amines or ammonia in combination with C02, refrigerants such as R-134a, R-245fa, Solvokane, as well as mixtures of solvents and mixtures with nano-sized or micron-sized solid absorbents.

23. A system for energy production utilising a thermodynamic cycle and a circulating working medium, said system comprising a hot source heat exchanger or evaporator (2), a turbine (3), a generator (4), a cold source heat exchanger (5), and a condensation device (100) according to any one of claims 1- 15, wherein the components of said system (1) are connected by a conduit and valve system (6a, 6b, 6c, 6d, 7) which is arranged to guide the working medium through the system.

24. The system according to claim 23, wherein the system further comprises a first pump (17) arranged to evacuate a liquid composition working medium from said condensation device (100) through a first conduit (6a).

25. The system according to claim 23 or 24, wherein said first conduit (6a) is divided into a second conduit (6b) arranged to guide a first stream (Q 1) of liquid composition working medium and a third conduit (6c) arranged to guide a second stream (Q2) of liquid composition working medium.

26. The system according to claim 25, wherein the second conduit (6b) is arranged to connect a liquid composition outlet (12) of said condensation device (100) to a liquid composition inlet (14) arranged in a top section (11) of said condensation device (100) and guide at least a part of the first stream (Ql) of working medium via the cold source heat exchanger (4) to cool said first stream (Ql) of liquid composition working medium.

27. The system according to claim 25 or 26, wherein the third conduit (6c) is arranged to connect the liquid composition outlet (12) of said condensation device (100) to the gas composition inlet (16) of said condensation device (100) and guide at least a part of the second stream (Q2) of working medium via the hot source heat exchanger (5) and the turbine (3).

28. The system according to any one of claims 25-27, wherein a fourth conduit (6d) arranged to guide a third stream (Q3) of working medium is branched off said third conduit (6c).

29. The system according to claim 28, wherein the fourth conduit (6d) is arranged to pass through the top section (11) of the condensation device (100) to permit heat transfer between the liquid composition working medium in the fourth conduit (6d) and the cooled liquid composition working medium in the top section (11) of the condensation device (100).

30. The system according to claim 29, wherein the fourth conduit (6d) is used for cooling other components in the thermodynamic closed-loop cycle, e.g. a pump (17, 22) or a unit for removal of non-condensable gases (30)

31. The system according to any one of claims 23-30, further comprising a unit for removal of non-condensable gases (30), wherein the fourth conduit (6d) is connected to a liquid composition working medium inlet (31) of the unit for removal of non-condensable gases (30).

32. The system according to claim 31, wherein the unit for removal of non-condensable gases (30) comprises a first gas composition working medium inlet (30a) arranged to guide gaseous medium from the condensation device (100) to the unit for removal of non-condensable gases (30) and a first liquid composition working medium outlet (30b) arranged to guide liquid medium from the unit for removal of non-condensable gases (30) to the condensation device (100).

33. The system according to claim 32, wherein said first gas composition working medium inlet (30a) of the unit for removal of non-condensable gases (30) is arranged below a perforated plate (20) of said condensation device (100) at an approximate same height as the gas composition inlet (16) of said con- densation device (100).

34. The system according to claim 32 or 33, wherein said first liquid composition working medium inlet (30b) of the unit for removal of non-condensable gases (30) is connected to the condensation device near the liquid composition outlet (12) of said condensation device (100).

Description:
CONDENSATION DEVICE AND METHOD COMPRISING A RAIN CONDENSER

Technical field

[0001] The present invention relates generally to a device and a method for converting at least one gas composition or a mixture of gases into a liquid through condensation after passage through an expansion device such as a turbine. More specifically, the invention may be used for condensation of the gaseous expanded working medium in a thermodynamic cycle.

Background of the Invention and prior art

[0002] Gas treatment including washing, extraction of undesirable components, absorption, condensation of one or more components, both in flow- through and dead-end configuration, is a standard unit operation in the oil, gas, and chemical industry, see e.g. "Grundoperationen chemischer Verfahren- stechnik", 8.ed., Vauck/Muller, ISBN3-527-28031-6, or Perry's Chemical Engi- neer's Handbook, ISBN 0-07-049479-7, section 18.41. Among the many techniques available for such gas treatment is the wide-spread counter-flow contacting falling liquid droplets with a gas stream flowing upwards. Falling droplets may form in a spray created in special nozzles where e.g. a liquid jet impinges on a small pin thereby creating a cone which subsequently breaks up into droplets of e.g. 10-500 micrometre size, alternatively the liquid is passed over a packed bed such as a multitude of e.g. Raschig rings.

[0003] Relevant disclosures in the field are US 2010/0236242, Kasra Farsad et al, "Systems and methods for processing of C02", US 4,991,780, R. Kannan et al, "Duocone spray nozzle", Krzysztof Karkoszka, Licentiate Thesis 2005, KTH Stockholm, "Theoretical investigation of water vapour condensation in presence of non-condensable gases", US 7,654,509, S. Freitas et al, "Desuper- heater spray nozzle", US 8,579,213, S. Myers et al, "Single circuit multiple spray cone pressure atomizers", Minoru Takahashi, "Study on vapor condensation heat transfer to liquid spray", 7 th international conference on nuclear engineering, Tokyo, Japan, April 19-23, 1999 (ICONE-7481) , US 2005/0056 711, Th . Mee, "Multiple spray apparatus", and industrial disclosures, e.g. web site descriptions on e.g. jet spray deaerators, all of which are incorporated herein by reference. A further relevant publication is GB 1 357 783 by Carrier Drysys Limited, incorporated herein by reference, which teaches gas treatment in a flow-through apparatus by jetting a liquid through peripheral openings. The liquid forms circular or arcuate curtains directed towards the side of the cas- ing, and the gas to be treated is flowing through said curtains. Gas absorption or phase change to liquid is not mentioned.

[0004] WO 2016/068778 discloses a method and apparatus for contacting a gas composition with a liquid composition for condensing the gas composition or components thereof, incorporated herein by reference. The apparatus com- prises a device having a plurality of spaced apart slots or impaction pin spray nozzles to create spray clouds of the liquid composition. In practice, the solution proposed by WO 2016/068778 consumes a high amount of energy, has a complicated structure making it expensive to manufacture and it is difficult to achieve the required droplet size. [0005] J.M. Moult et al, "Single rain tray type condensers", Proceedings of The South African Sugar Technologists' Association, June 1979 discloses the use of a single tray rain type condenser in the sugar industry. The rain condenser is a perforated "shower" plate disposed at the top of the tank to create fine liquid droplets. The gas is then fed underneath the plate to be condensed. The rain condenser is normally used "pressure-free", where only the height of the liquid pillar above the perforated plate constitutes the driving pressure.

[0006] Other known solutions involve using heat exchangers to condense the working medium. The advantage is that no tank is needed. However, large heat exchangers are required and the risk of creating a high counter pressure increases.

[0007] The engineer who has the task of providing an efficient process is confronted with a number of challenges which are well highlighted among others in Farsad's and Mee's disclosures: a) fill the gas space with as many liquid

(droplets or other dispersed forms) as possible, b) provide a large surface at low energy consumption, c) balance available surface with speed of absorption, extraction, washing etc., d) use available volume efficiently, e) prevent losses, e.g. by small droplets condensing to larger droplets, or by liquid at high speed hitting a wall of the container, f) prevent adverse interference with the gas stream, g) manage temperature increases, e.g. caused by absorption or condensation enthalpies, and h) provide cooling or warming of gas and/or liquid streams as the case may be. Some of these challenges are mutually exclusive, and technical solutions are often compromises, see e.g. both Farad and Mee suggesting multiple spray sections.

Summary of invention

[0008] An object of the present invention is to provide an improved device and method for overcoming all or some of the disadvantages and problems described above in connection with the state of the art. [0009] This object is achieved by the present invention, wherein in a first aspect there is provided a condensation device for a thermodynamic cycle adapted to convert a gas composition#>f a working medium into a liquid composition of said working medium through direct contact condensation, the condensation device comprising: a vessel having an essentially cylindrically shaped side wall, a top section, a bottom section, a liquid composition inlet, and a liquid composition outlet, the liquid composition inlet being arranged in the top section and the liquid composition outlet being arranged in the bottom section of the vessel; and a perforated plate arranged in the top section of the vessel to delimit a space in fluid communication with the liquid composition inlet, wherein the perforated plate comprises a plurahty of holes through which the liquid composition may pass to create a plurality of spray clouds comprising the liquid composition, wherein the vessel further comprises a gas composi- tion inlet, wherein the gas composition inlet is arranged slightly below the perforated plate in the side wall of the vessel.

[0010] The condensation device according to the present invention is compact, simple, and less expensive to manufacture and overcomes the disadvantages of the prior art by providing a large surface area of liquid sprays or droplets to enable maximum contact between the incoming gas composition and the liquid composition whilst minimising energy consumption and space requirement.

[0011] In a preferred embodiment, a centre line of the gas composition inlet is arranged at an angle to a tangent to the side wall of the vessel at a point of intersection between the centre line and the side wall. Said angle may be larger than 90°, preferably between 95° and 160°, more preferably between 100° and 140°, most preferably said angle is 115°.

[0012] It is advantageous to let the gas enter just below the top section of the condenser, and it is preferred to let the gas enter tangentially into the vessel, i.e. not orthogonal to the side wall of the vessel, in order to achieve a spiral or swirling trajectory of the gas. Said swirling trajectory creates a cyclone of gas composition in the vessel. The cyclone helps to further break the liquid droplets, which in turn helps with the condensation.

[0013] In another embodiment, a centre line of the gas composition inlet is arranged at an angle relative to the z-axis of the vessel. The gas composition inlet may be arranged horizontally, i.e. at 90° relative to the z-axis of the condenser, or up to 15° off said horizontal orientation. The orientation of the gas composition inlet relative to the z-axis of the vessel further dictates the formation of the cyclone of gas composition in the vessel as explained above. [0014] In a preferred embodiment, the top section of the vessel is dome- shaped. The dome shape decreases the height and bulk of the vessel whilst maintaining a certain volume of the space above the perforated plate to ensure a compact design. [0015] In a preferred embodiment, the bottom section of the vessel has a conical shape converging towards the liquid composition outlet. The converging, conical shape ensures that the liquid composition is directed towards the liquid composition outlet. Thus, the liquid level in the condenser may be kept as low as possible in order to maximise the gas space and space for condensation. However, a certain height of the liquid level is important in order to guarantee that no gas enters the pump or that no liquid is gasified due to low local pressures, i.e. prevent cavitation.

[0016] The liquid level is maintained and controlled. During operation of the device, a dynamic and complicated equilibrium between gas flow, liquid flow, liquid level, and heat removal by cooling needs to be managed. This is done automatically.

[0017] In a preferred embodiment, the condensation device further comprises a supporting member arranged adjacent the perforated plate, such as above or below the perforated plate. [0018] In a preferred embodiment, the supporting member is arranged above the perforated plate and further comprising a porous material arranged between the supporting member and the perforated plate. Preferably, the supporting member comprises a grating.

[0019] In a preferred embodiment, the condensation device further com- prises a vortex breaker arranged in or near the liquid composition outlet, the vortex breaker including one or more of radial vanes, baffles, and/or curved plates. Apart from maintaining a certain liquid level, vortex breakers are employed to ascertain that no gas exits the liquid composition outlet. Gas in the liquid composition may cause harm to additional devices into which the liquid composition is arranged to enter. For example, pumps arranged to pump the liquid composition from the condensation device to other parts of a system comprising said condensation device. [0020] In a preferred embodiment, the condensation device further comprises a diffuser arranged at the gas composition inlet. The diffuser is provided to decelerate the gas composition exiting the turbine in a controlled manner, transforming the kinetic energy to potential energy in the form of increased static pressure. The diffuser aids in minimising build-up of counter pressure in the vessel, which otherwise would have a negative impact on the turbine power.

[0021] In a preferred embodiment, the perforated plate has a perforation percentage (i.e. the ratio between the total area of the holes and the surface area of the plate) in the range of l%-40%, preferably 5%-30%, most preferably 10%-20%. The number of holes per unit area determines the flow resistance to a degree and therefore the pressure differential between the top and the main section of the vessel.

[0022] In a preferred embodiment, the holes in the perforated plate have a diameter in the range 0.01-5 mm, preferably 0.2-0.8 mm, most preferably 0.4- 0.6 mm.

[0023] In a second aspect of the present invention, there is provided a method for converting at least one gas composition of a working medium into a liquid composition of said working medium through a thermodynamic cycle utilising direct contact condensation in a condensation device according to the first aspect, comprising the steps:

- feeding the liquid composition of said working medium into a liquid composition inlet above a perforated plate of said condensation device and wherein the liquid composition is let to pass through perforated plate of said condensation device, thereby forming a plurality of liquid sprays comprising droplets of the liquid composition;

- feeding the gas composition of said working medium into a gas composition inlet of said condensation device such that the gas composition contacts the liquid sprays, wherein said gas composition is absorbed or condenses into a stream of liquid composition;

- collecting the stream of liquid composition after having absorbed or condensed the gas composition fed into said condensation device;

- redirecting a first stream of the collected stream of liquid composition for heat transfer with a cold source, and recirculating the cooled first stream to a top section of the condensation device;

- redirecting a second stream of the collected liquid composition for heat transfer with a hot source, wherein the liquid composition in said second stream vaporises into said gas composition; and

- adjusting the flow rate of the liquid composition entering the liquid composition inlet to achieve complete, immediate condensation of the gas composition.

[0024] In one embodiment, the method is used to condense the working medium of a Rankine Cycle after its passage through an expansion device such as a turbine. The expanded gas is contacted with a plurality of falling liquid sprays or droplets which in turn is created by passing a liquid composition through a perforated plate. The construction has similarity with a shower, and the objectives in designing an effective shower are a) to minimise the energy consumption for creating a large surface of streams or droplets, b) minimise the space requirement and c) to enable maximum contact between the incoming gas composition and the liquid composition.

[0025] By means of the method according to the present invention, ideal condensation of the gas composition may be achieved wherein all the liquid molecules of the liquid composition are used to cool and condense all the gas mole- cules of the gas composition, i.e. substantially no pressure differential between the gas pressure in the vessel and the vapour pressure corresponding to the liquid temperature at the bottom of the vessel. A certain, negligible pressure differential may occur due to non-condensed gas in the vessel, such as e.g. non- condensable gases (air etc.). Hence, the method according to the present inven- tion achieves a phase conversion of the gaseous working medium without generating a counter pressure in the turbine.

[0026] Apart from non-condensable gases which may be present due to leakage in small concentrations in the gas mixture, all gas or gaseous working medium is converted to liquid. This requires some cooling. During the condensa- tion of gas at the surface of the liquid streams or droplets, energy, more exactly, condensation enthalpy is liberated creating a temperature increase of the liquid. In order to maintain a certain average temperature level in the condensation device, the liquid stream is pumped into a heat exchanger which transfers heat to a cold source. [0027] In a preferred embodiment, the method further comprises feeding the gas composition tangentially into the condensation device in order to achieve a spiral or swirling trajectory of the gas composition.

[0028] In an advantageous embodiment, the method further comprises feeding the gas composition at an angle relative a z-axis of the vessel into the con- densation device.

[0029] The gas may enter the reactor from any side of the condenser device. It is advantageous to let the gas enter just below the top section of the condenser, and it is preferred to let the gas enter tangentially instead of radially, i.e. not orthogonal or normal to the side wall of the vessel, in order to achieve a spiral or swirling trajectory of the gas. Said swirling trajectory create a cyclone of gas composition in the vessel. The cyclone helps to further break the liquid droplets, which in turn help with the condensation. The gas composition inlet may be arranged horizontally, i.e. at 90° relative to the z-axis of the condenser. Alternatively, the gas composition can be fed into the condensation device at an angle up to 15° off said horizontal orientation.

[0030] In an alternative embodiment, the method further comprises redirecting a portion of the second stream of the collected stream of liquid composition into a third stream and passing the third stream through the top section of the vessel to be cooled.

[0031] In a further preferred embodiment, the third stream of the collected stream of liquid composition is used for cooling other components in the thermodynamic closed-loop cycle, e.g. a pump or a unit for removal of non-conden- sable gases.

[0032] In an advantageous embodiment, the first stream is adjusted to comprise 80%-99.9% of the collected stream of liquid composition and the second stream is adjusted to comprise 0.1%-20%, preferably 1%-10%, more preferably 3%-8%, most preferably 4%-5%, of the collected stream of liquid composition. The liquid stream exiting the heat exchanger is partly fed to the evaporation section of the process, and the remaining part is fed back to the top of the condensation device in order to form said plurality of liquid streams or droplets.

[0033] In a further preferred embodiment, the method is used for ideally complete absorption or condensation of a working medium in a Rankine cycle, including Organic Rankine Cycles, Kalina cycle, Carbon Carrier cycle and other thermodynamic cycles for energy production, and heat pumps, wherein said working medium is selected from the group consisting of water, hydrocarbons such as methanol and ethanol and isopropanol, ketones such as acetone and MEK, toluene, paraffin, amines or ammonia, amines or ammonia in com- bination with C02, refrigerants such as R-134a, R-245fa, Solvokane, as well as mixtures of solvents and mixtures with nano-sized or micron-sized solid absorbents. [0034] In a third aspect of the present invention, there is provided a system for energy production utilising a thermodynamic cycle and a circulating working medium, said system comprising a hot source heat exchanger or evaporator, a turbine, a generator, a cold source heat exchanger, and a condensation device according to the first aspect described above. The components of said system are connected by a conduit and valve system which is arranged to guide the working medium through the system.

[0035] The system and method is particularly useful when utilising Rankine cycles or Organic Rankine cycles employing one or more of the following work- ing mediums exhibiting boiling points at 100 kPa (1 bar) of below 105 °C, such as water, ethanol, acetone, isopropanol, toluene, paraffin, refrigerants, and others.

[0036] In an embodiment said system further comprises a first pump arranged to evacuate a liquid composition working medium from said condensa- tion device through the liquid composition outlet and a first conduit. Said pump is arranged directly below the condensation device and is arranged to create a flow of hquid working medium from the condensation device. Said pump may also be used to control the flow. To prevent cavitation in the pump it is important that the working medium is completely transformed into hquid medium comprising no gaseous medium.

[0037] In another preferred embodiment, said first conduit is divided into a second conduit arranged to guide a first stream of liquid composition working medium and a third conduit arranged to guide a second stream of liquid composition working medium. [0038] In one preferred embodiment, the second conduit is arranged to connect a liquid composition outlet of said condensation device to a liquid composition inlet arranged in a top section of said condensation device and guide at least a part of the first stream of working medium via the cold source heat exchanger to cool said first stream of liquid composition working medium. By transferring away the heat absorbed by the liquid composition during condensation of the gas composition, the temperature of the liquid composition is maintained at a desired average level for optimal condensation.

[0039] In one embodiment, the third conduit is arranged to connect the liq- uid composition outlet of said condensation device to the gas composition inlet of said condensation device and guide at least a part of the second stream of working medium via the hot source heat exchanger and the turbine.

[0040] When the working medium is guided through the hot source heat exchanger the liquid working medium is evaporated and changed into the gase- ous liquid medium. The gaseous working medium is expanded in the turbine hereby generating electricity in the generator connected to the turbine.

[0041] In one additional embodiment, a fourth conduit arranged to guide a third stream of working medium is branched off said third conduit. In one embodiment, the fourth conduit is arranged to pass through the top section of the condensation device to permit heat transfer between the liquid composition working medium in the fourth conduit and the cooled liquid composition working medium in the top section of the condensation device. Preferably the fourth conduit is used for cooling or arranged to cool other components in the thermodynamic closed-loop cycle, e.g. a pump or a unit for removal of non-condensable gases.

[0042] In one additional embodiment, the system according to the above further comprising a unit for removal of non-condensable gases, wherein the fourth conduit is connected to a liquid composition working medium inlet of said unit for removal of non-condensable gases. [0043] A system for energy production utilising a thermodynamic cycle, particularly when utilising Rankine cycles or Organic Rankine cycles employing working mediums exhibiting boiling points at 100 kPa (1 bar) of below 105 °C, is sensitive to air or other non-condensable gases entering the system. When adding a unit for the removal of non-condensable gases said non-condensable gases may be removed.

[0044] In one embodiment, the unit for removal of non-condensable gases comprises a first gas composition working medium inlet arranged to guide gaseous medium from the condensation device to the unit for removal of non-condensable gases and a first liquid composition working medium outlet arranged to guide liquid medium from the unit for removal of non-condensable gases to the condensation device.

[0045] In one embodiment, said first gas composition working medium inlet of the unit for removal of non-condensable gases is arranged below a perforated plate of said condensation device at an approximate same height as the gas composition inlet of said condensation device.

[0046] In one embodiment, said first liquid composition working medium inlet of the unit for removal of non-condensable gases is connected to the condensation device near the liquid composition outlet of said condensation device.

Brief description of drawings

[0047] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 shows a schematic view of a system arranged to work according to thermodynamic cycle for energy production;

Fig. 2 shows a perspective cutaway view of a condensation device according to a first aspect of the present invention;

Fig. 3 shows a perspective view of a perforated plate used in a condensation device according to a first aspect of the present invention;

Fig. 4a shows a cutaway view of the condensation device taken at cut A-A in

Fig. 5, through the gas composition inlet, according to one aspect of the present invention; Fig. 4b shows a detail view of the gas composition inlet taken in the flow direction of the gas compound; and

Fig. 5a shows an external view of the condensation device according to one embodiment of the present invention;

Fig. 5b shows an external view of the condensation device according to another embodiment of the present invention; and

Fig. 6 shows a detail view of the condensation device comprising an air trap unit according to another aspect of the invention.

Detailed description of embodiments

[0048] In the following, a detailed description of a method and device for converting a gas composition of a working medium into a liquid composition of said working medium in accordance with the present invention is provided.

[0049] Fig. 1 shows a schematic view of a system 1 for energy production illustrating the principle underlying the different aspects of the present inven- tion. Said system for energy production is utilising a thermodynamic cycle and a circulating working medium. The thermodynamic cycle is preferably an organic Rankine cycle. Said system comprising an evaporator or hot source heat exchanger 2, a cold source heat exchanger 5, a turbine 3, a generator 4 and a condensation device 100. Said system 1 may in one aspect of the invention also comprise a unit for removal of non-condensable gases 30, also called an air trap unit (ATU), as further described below. The different components of said system 1 is connected by a conduit and valve system which is arranged to guide the working medium through the system. The system 1 further comprises at least a first pump 17, 22 arranged to evacuate a liquid composition working medium from said condensation device 100 through a first conduit 6a of said conduit and valve system.

[0050] On the left-hand side of Fig. 1, a hot source heat exchanger 2, also called evaporator, is located. The working medium is heated to vaporization by an incoming hot source (HS), e.g. waste heat from industrial processes or from geothermal sources. The hot vaporised gaseous working medium is then passed through a turbine 3 which expands the working medium and drives a generator 4 for production of electrical energy. The expanded hot working medium, still in gaseous form, is then fed into a condensation device 100 to be converted back to liquid form before being recirculated to the hot source heat exchanger 2 to complete the closed-loop cycle 1, as shown on the left-hand side of Fig. 1.

[0051] The condensation device 100 comprises a vessel 10 or container 10 and a perforated plate 20. In said condensation device the working medium is arranged to change phase from a gaseous state to a liquid state. As shown at the bottom of Fig. 1, the liquid state composition of the working medium is collected after being evacuated through a bottom section 12 of the vessel 10 by means of a first pump 17, indicated by collected stream of liquid composition Q fed through the first conduit 6a. The working medium stream of liquid compo- sition Q is separated by the conduit and valve system 6, 7 into two streams Ql, Q2, wherein a first, bigger stream Ql is fed through a second conduit 6b to a cold source heat exchanger 5 to be cooled before being led back to a top section 11 of the vessel 10, as shown on the right-hand side of Fig. 1, and a second, smaller stream Q2 is recirculated through a third conduit 6c to the hot source heat exchanger 2. A second pump 22 may be provided to circulate the second stream Q2 in the second conduit 6c back to the hot source heat exchanger 2. The first stream Ql may comprise 80%-99.9% of the collected liquid composition Q and the second stream Q2 may comprise 0.1%-20%, preferably 1%-10%, more preferably 3%-8%, most preferably 4%-5%, of the collected liquid compo- sition Q. The cold source (CS) may be a cold sink, and the heat energy given off by the second stream Q2 may be used in different applications.

[0052] A fourth conduit 6d arranged to guide a third stream Q3 of working medium may also be branched off said third conduit 6c. The fourth conduit 6d is arranged to pass through the top section 11 of the condensation device 100 to permit heat transfer between the liquid composition working medium in the fourth conduit 6d and the cooled liquid composition working medium in the top section 11 of the condensation device 100. The fourth conduit 6d is used for cooling other components in the thermodynamic closed-loop cycle, e.g. a pump or a unit for removal of non-condensable gases 30. [0053] In Fig. 2, a cutaway view of the condensation device 100 comprising the vessel 10 and the perforated plate 20 is shown. Said vessel 10 is having a generally cylindrical shape comprising a cylindrical side wall 13, a top section 11 and a bottom section 12. From the top section 11 of the vessel 10, the cooled liquid composition is allowed to pass through the perforated plate 20. The per- forated plate having a plurality of holes 24, to create a drizzle of liquid sprays thus acting as a spray condenser. The resulting multitude of fine liquid droplets provides a large surface area for contacting the impinging molecules of the gas composition to enhance and accelerate condensation thereof.

[0054] The perforated plate 20 is arranged in the top section 11 of the vessel 10, thus creating a space 18 above the perforated plate 20. The liquid composition is led into the space 18 through a liquid composition inlet 14 in the vessel 10. In the exemplary embodiment of Fig. 2, the liquid composition inlet 14 is provided in the form of a conduit entering a side wall 13 of the vessel 10 and terminating in a central large opening 23 in the perforated plate 20. Of course, the liquid composition inlet 14 may also be arranged in any other suitable position in fluid communication with the space 18 above the perforated plate 20 in the top section 11 of the vessel 10.

[0055] The perforated plate 20 may be relatively thin (about 0.5 mm thickness) in order to produce fine sprays of the liquid composition passing through the holes 24. In operation, a certain level of the liquid composition above the perforated plate 20 is required to produce a uniform flow. As a result, the weight, or the pressure of the liquid composition in the space 18 above the perforated plate 20 may cause the perforated plate 20 to buckle or deform. To prevent deformation of the perforated plate 20, a supporting member 21 such as a grating may be arranged adjacent the perforated plate 20, either below as shown in Fig. 2 or above (not shown). The grating comprises openings bigger than the holes 24 in the perforated plate 20 so as not to adversely affect the formation of liquid sprays. [0056] In the case of a supporting member 21 arranged above the perforated plate 20, a porous material may be arranged between the supporting member 21 and the perforated plate 20 to ensure that the liquid composition is guided to reach all the holes 24 in the perforated plate 20. With this solution, the supporting member 21 will not cover any of the holes 24 in the perforated plate 20. Alternatively, the perforated plate 20 may be of a stiffer and/or thicker material and being either perforated with holes or porous, or a "sandwich" solution wherein two or more plates may be used, with the upper plate being thicker and having larger holes.

[0057] Arranged slightly below the perforated plate 20 in the side wall 13 of the vessel 10 is an inlet 16 for the gas composition. The gas composition inlet 16 is positioned so as to maximise contact between the spray of liquid composition and the gas composition entering the vessel 10.

[0058] In Figs. 4a and 4b said gas composition inlet 16 of said condenser device is further described. The gas composition inlet 16 may be arranged at an angle a (i.e. non-perpendicular) to a tangent to the side wall 13 of the vessel 10 at the point of intersection between the centre line CL and the side wall 13, as illustrated in Fig. 4a. This to create a tangential flow of the gas composition essentially along the side wall 13. The angle a is larger than 90°, preferably between 95° and 160°, more preferably between 100° and 140°, most preferably said angle is 115°. The centre line CL is arranged at the centre of the preferably circular or near circular gas composition inlet 16, approximately parallel to the flow direction FD of the gas, see Figs. 4a and 4b.

[0059] The gas composition inlet 16 may be arranged horizontally, i.e. said centre line of the gas composition inlet is at an angle β relative to the z-axis of the condenser, see Figs. 5a and 5b. In one embodiment, shown in Fig. 5a said angle β is an angle βΐ of 90°. In another embodiment, see Fig. 5b, said angle β is an angle β2 is less than 90°, preferably up to 15° off said horizontal orientation in an upward direction. I.e. said angle β2 is between 75° and 90° relative to the z-axis of the condenser, preferably said angle is 80°.

[0060] Furthermore, the gas composition inlet 16 may comprise a diffuser (not shown) to decelerate the gas composition exiting the turbine in a controlled manner, transforming the kinetic energy to potential energy in the form of increased static pressure. The diffuser aids in minimising build-up of counter pressure in the vessel 10, which otherwise would have a negative impact on the turbine power.

[0061] In the bottom section 12 of the vessel 10, a liquid composition outlet 15 is provided for evacuating the liquid composition from the vessel 10, using e.g. a first pump 17 (not shown in Fig. 2) to the first conduit 6a. The first pump 17 is preferably arranged directly below the liquid composition outlet 15 so as to minimise the required liquid level in the vessel 10 and to reduce the risk of cavitation. A vortex breaker 19 may be provided at or near the liquid composition outlet 15, e.g. a pair of plates or sheets arranged in the form of a vertical cross, or curved to conform to the shape of the bottom section 12 of the vessel 10 and partially covering the liquid composition outlet 15. As may be seen in Fig. 2, the shape of the bottom section 12 of the vessel 10 is somewhat conical and converging towards the liquid composition outlet 15 to direct the liquid composition towards the outlet 15.

[0062] In Fig. 3, the perforated plate 20 is illustrated in a perspective view. As may be seen, the plate comprises a plurality of holes 24 having a diameter in the range 0.01-5 mm. Smaller holes give finer liquid sprays, but have the disadvantage of becoming clogged up and are also more difficult to manufacture. In an operational setting, it has been found that holes of about 0.5 mm diameter create an optimal size and spray of liquid droplets as well as providing sufficient flow of liquid composition through the holes 24 to achieve rapid condensation of the incoming gas composition. The perforation percentage of the plate, i.e. the ratio between the total area of the holes 24 and the surface area of the plate, is selected from the range l%-40%, preferably 5%— 20%. The perforation percentage (i.e. the number of holes 24) and diameter of the holes 24 may be selected within the specified ranges to find the optimal values in order to obtain an optimal flow rate of the liquid composition and achieve immediate complete condensation of the incoming gas composition. In the context of the present invention, the term 'immediate' should be interpreted as spanning a short time period after the introduction of each gas molecule of the gas composition into the condensation vessel 10, e.g. an average vapour residence time of maximum 1 s, preferably 0.1 s.

[0063] In one exemplary embodiment, a vessel 10 having a height of 1200 mm and volume of 0.5 m 3 was used, with the temperature of the gas composition being about 50°C and the temperature of the liquid composition being about 20°C, the holes 24 of the perforated plate 20 were 0.5 mm in diameter and the perforation percentage was about 19%. With adjusted parameters for the flow of the gas composition and the liquid composition, and gas density, an average gas residence time in the vessel was calculated to be about 10 ms, which corresponds to complete, immediate condensation of the gas composition with a drive pressure of about 70 mbar (given by the height of the liquid column above the perforated plate) and a zero or negligible pressure differential (about 20 mbar) between the gas pressure in the vessel 10 and the vapour pressure corresponding to the liquid temperature at the bottom of the vessel 10. If the pressure differential should rise to about 200 mbar, the average gas residence time in the vessel increases to about 0.1 s.

[0064] Now returning to Fig. 1. The unit for removal of non-condensable gases or ATU 30 is arranged to remove non-condensable gases, such as air, un- intentionally entering the system for energy production using a working medium in a thermodynamic cycle due to small leaks. Accumulation of undesired non-condensable gases is a known problem in systems for energy production, for example power plant and decrease the efficiency of the power plant. Air leaks into the system not only operated under vacuum but also into processes operated above atmospheric pressure. But a unit for removal of non-condensable gases is particularly useful in a system for energy production utilising a thermodynamic cycle, particularly when utilising Rankine cycles or Organic Rankine cycles employing working mediums exhibiting boiling points at 100 kPa (1 bar) of below 105 °C.

[0065] Said unit for removal of non-condensable gases 30 comprises a secondary condensation vessel 30 in fluid communication with the vessel 10 of the condensation device 100 via a number of inlets and outlets, valves, and corresponding conduits. A pair of first inlets and outlets 30a, 30b connects the ATU 30 with the vessel 10 directly, wherein said first inlet 30a is a first gas composition working medium inlet arranged to guide gaseous medium from the vessel 10 to the ATU 30 and said first outlet 30b is a first hquid composition working medium outlet arranged to guide liquid medium from the ATU 30 to the vessel 10. Furthermore, a liquid composition working medium inlet 31 to the ATU 30 is connected to the hquid composition outlet 15 of the vessel 10 via a fourth conduit 6d. The first gas composition working medium inlet 30a of ATU 30 is arranged in the vessel 10 below the perforated plate 20 of said condensation device 100 at an approximate same height as the gas composition inlet 16 of said condensation device. The first liquid composition working me- dium outlet 30b of the ATU 30 is connected to the condensation device near the hquid composition outlet 12 of said condensation device 100.

[0066] By controlling the flow of cooled hquid working medium and gaseous working medium into the secondary condensation vessel 30 through the liquid composition working medium inlet 31 and the first gas composition working medium inlet 30a, the cooled liquid working medium condenses the gaseous working medium and at the same time the pressure in the secondary condensation vessel 30 increases. Hereby it is ensured that all condensable working medium in the secondary condensation vessel 30 is condensed and trapped in bottom part of the secondary condensation vessel 30. The liquid working me- dium is returned to the system 1 through the liquid composition working medium outlet 30b. A second outlet 32 from the ATU 30 is provided to evacuate non-condensable gases separated from the liquid composition out of the ATU 30.

[0067] The fourth conduit 6d is split off from the third conduit 6c and is passed through the top section 11 of the vessel 10. Hence, a portion of the second stream Q2, constituting a third stream Q3, passing through the fourth conduit 6d may be cooled by heat transfer with the liquid composition in the space 18 in the top section 11 before being guided to the ATU 30. The third stream Q3 may comprise l%-5% of the collected liquid composition Q. [0068] In Fig. 2 and Fig. 6 said fourth conduit 6d is further shown. In the embodiment shown in Fig. 2 and 6, the conduit 6d is a spiral shaped conduit arranged in the space 18 of the top section 11 of the vessel 10, i.e. above the perforated plate 20. The fourth conduit 6d is chosen to circulate several loops in the space 18. The working medium guided in said third conduit loop is cooled by the flow of working medium entering through the liquid composition inlet 14, which in turn is cooled by the cold source heat exchanger 5.