EP2923044A1 - A modified organic rankine cycle (orc) process - Google Patents
A modified organic rankine cycle (orc) processInfo
- Publication number
- EP2923044A1 EP2923044A1 EP13853630.5A EP13853630A EP2923044A1 EP 2923044 A1 EP2923044 A1 EP 2923044A1 EP 13853630 A EP13853630 A EP 13853630A EP 2923044 A1 EP2923044 A1 EP 2923044A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- working medium
- flow
- medium flow
- lng
- heat exchanger
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C1/00—Gas-turbine plants characterised by the use of hot gases or unheated pressurised gases, as the working fluid
- F02C1/04—Gas-turbine plants characterised by the use of hot gases or unheated pressurised gases, as the working fluid the working fluid being heated indirectly
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
Definitions
- the present invention relates to a modified Organic Rankine Cycle (ORC) process.
- ORC Organic Rankine Cycle
- the process according to the present invention reduces or prevents ORC pump cavitation caused by vapor bubbles in the ORC working medium entering the ORC pump.
- Natural gas is much used as fuel and is supplied in gaseous form but is often stored as liquid natural gas, LNG. LNG needs to be stored very cold.
- the exhaust gas from natural gas fuelled engines is clean. Heat recovery from gas engine exhaust gas is suitable since a heat exchanger in the exhaust gas flow will remain clean. High temperature exhaust and cooling water in machinery is used for power generation by expander machine.
- An example of power cycle with expander machine used for this purpose is Organic Rankine Cycle (ORC).
- ORC uses low boiling point working medium in order to utilize heat sources with relatively low temperatures.
- An ORC is a thermodynamic process where a working medium is circulated in a closed loop. Liquid working medium is pumped up to a certain pressure. Then, it is heated. The heat source is often waste heat from combustion machinery.
- Part of the energy taken up by the working medium during heating is transferred to an expansion machine and is utilized as shaft power from the expansion machine.
- the working medium flow out from the expansion machine is condensed in a condenser by a cooling medium.
- the condenser cooling medium is normally cooling water from sea or aircooler.
- the condenser is transferring working medium vapor into liquid condition and the working medium out from the condenser is in saturated condition.
- the condensed working medium is flowing from the condenser and in return to the pump. In the working medium flow from the condenser to the pump there is a risk for vapor bubbles in the liquid since the liquid is in saturated condition in the condenser and has a low boiling point.
- NPSH net positive suction head
- US201 1/0048012 describes an energy recovery system and method where the ORC working medium is condensed and sub-cooled in a single flow by a cooling medium. US201 1/0048012 is thereby a temperature control system for sub-cooling of working medium in order to reduce the risk for pump cavitation.
- WO 201 1/057724 describes that a non-condensable gas is supplied above the liquid downstream of an ORC working medium condenser. By introducing a partial pressure from a non-condensable gas during condensation of the working medium the working medium liquid flowing to the pump will be sub-cooled since there is no non-condensable gas in the liquid flowing to the pump. WO 201 1/057724 is thereby a pressure control system to reduce the risk for pump cavitation.
- the object of the present invention is to provide an alternative solution for reducing or preventing pump cavitation in an Organic Rankine Cycle (ORC) process.
- ORC Organic Rankine Cycle
- the present invention relates to an Organic Rankine Cycle (ORC) process, which is modified for reducing or preventing cavitation of the pump in the ORC cycle.
- ORC Organic Rankine Cycle
- the flow from the ORC expansion machine is split into two flows, of which one flows through a condenser and the other flows through a cooler and is cooled to a temperature which preferably is significantly below its condensing temperature by heat exchanging with LNG.
- the two flows are re-connected in a mixing device so that vapor bubbles in the flow from the condenser are separated from the liquid and mixed with the cold flow from the LNG heat exchanger and thereby condensing the bubbles by selective cooling and thereby reducing or preventing cavitation of the ORC pump.
- the process is preferably utilizing waste heat from LNG fuelled machinery.
- the present invention provides a modified Organic Rankine Cycle (ORC) process, for reducing or preventing pump cavitation, wherein an ORC working medium flow is pressurized in a pump, heated in a heat exchanger by the use of a waste heat flow, and expanded in an expansion machine, characterized in that
- the working medium flow from the expansion machine is split in a splitting device into two parallel working medium flows, the working medium flow is condensed in a condenser by the use of a cooling medium flow, the working medium flow is cooled in a heat exchanger to a temperature lower than the temperature of the working medium flow from the condenser by heat exchanging with an LNG flow flowing from an LNG fuel storage tank through the heat exchanger and to a LNG fuelled machinery, and the condensed working medium flow from the condenser and the cooled working medium flow from the heat exchanger are combined in a mixing device positioned upstream of the pump.
- the condensed working medium flow from the condenser is introduced below the cooled working medium flow from the heat exchanger in the mixing device.
- the working medium flow is cooled in the heat exchanger to about the temperature of the LNG flow.
- the waste heat flow comes from the LNG fuelled machinery.
- the cooling medium flow for the condenser is cooling water from sea or air cooler.
- the LNG flow is vaporized by heat exchanging with the OCR working medium flow in the heat exchanger and supplied as fuel to the LNG fuelled machinery with a temperature higher than the ORC working medium condensing temperature.
- Fig. 1 schematically illustrates the modified Organic Rankine Cycle process according to the present invention.
- the modified Organic Rankine Cycle process according to the present invention is illustrated in figure 1 .
- An ORC working medium flow 6 in the modified Organic Rankine Cycle is pressurized in a pump 4.
- the pressurized working medium flow 6 from the pump 4 is heated in a heat exchanger 3 by the use of a waste heat flow 7, and the heated working medium flow 6 is then expanded in an expansion machine 5.
- the working medium flow 6 from the expansion machine 5 is split in a splitting device 13 into two parallel working medium flows 6a, 6b. Then, the working medium flow 6a from the splitting device 13 is condensed in a condenser 2 by the use of a cooling medium flow 8, and the working medium flow 6b from the splitting device 13 is cooled in a heat exchanger 9 to a temperature lower than the temperature of the working medium flow 6a from the condenser 2 by heat exchanging with an LNG flow 10 flowing from an LNG fuel storage tank
- the condensed working medium flow 6a from the condenser 2 and the cooled working medium flow 6b from the heat exchanger 9 are combined in a mixing device 1 1 which is positioned upstream of the pump 4, so that the cooled working medium flow 6b condenses vapor bubbles separated from the liquid in the working medium flow 6a.
- the condensed working medium flow 6a from the condenser 2 can be introduced below the cooled working medium flow 6b from the heat exchanger 9 in the mixing device 1 1 .
- the working medium flow 6b can be cooled in the heat exchanger 9 to about the temperature of the LNG flow 10.
- the LNG flow 10 can be vaporized by heat exchanging with the OCR working medium flow 6b in the heat exchanger 9 and supplied as fuel to the LNG fuelled machinery 1 with a temperature higher than the ORC working medium condensing temperature.
- the present modified Organic Rankine Cycle (ORC) process may take waste heat from LNG fuelled engine, gas turbine or other LNG fuelled machinery 1.
- the waste heat flow 7 comes from the LNG fuelled machinery 1 .
- the waste heat may come from warm exhaust and cooling water.
- the ORC working medium is pressurized by pump 4 in liquid condition, heated in a heat exchanger 3 with waste heat flow 7, preferably from the LNG fuelled machinery 1 , and sent through an expansion machine 5.
- the flow rate of the ORC working medium that is utilizing the waste heat from the LNG machinery is much larger than the flow rate of the LNG fuel to the machinery.
- Flow 6a is sent through condenser 2 where the flow is condensed by cooling medium 8.
- the cooling medium in the cooling medium flow 8 can be cooling water from sea or air cooler.
- Flow 6b is sent through the heat exchanger 9 where it is cooled by LNG that is supplied as fuel from the storage tank 12 to the LNG machinery 1.
- the working medium flow 6b out from the heat exchanger 9 will be cooled and may be cooled close to LNG temperature.
- the flows 6a and 6b are re-connected into one flow in the mixing device 1 1 .
- the mixing device 1 1 is located upstream of and preferably close to pump 4.
- the mixing device flow outlet leading to the pump 4 is located at the bottom part of the mixing device 1 1 , the flow 6b is introduced in the top part of the mixing device 1 1 and the flow 6a is introduced between the bottom and top of the mixing device 1 1.
- the mixing device 1 1 has a flow area that is larger than the flow area of the flow from 1 1 to the pump, and the mixing device thereby has a lower flow velocity than the velocity of the flow from the mixing device 1 1 to the pump 4.
- the flow area of the mixing device 1 1 is so large and the flow velocity is so low that vapor bubbles in the liquid flow 6a are floating up and separated from the liquid.
- the separated bubbles are cooled and condensed by mixing with the colder liquid flow 6b and thereby preventing bubbles to be transported into the pump.
- the present invention is a modified ORC cycle to reduce or prevent ORC pump cavitation by preventing vapor bubbles to flow from downstream condenser to the pump. Bubbles are separated from flow 6a from the condenser 2 and condensed by mixing with the cold flow 6b and thereby are bubbles prevented to flow into pump 2. The cold flow 6b is mixed into the flow to the pump 4 and is thereby cooling the flow to the pump 4.
- the condensed working medium flow 6a from the condenser 2 and the cooled working medium flow 6b from the heat exchanger 9 are combined in a mixing device 1 1 positioned upstream of the pump 4 so that vapor bubbles are separated from the liquid in the working medium flow 6a and that the cooled working medium flow 6b is mixed with and condenses the vapor bubbles that have been separated from the liquid in the working medium flow 6a thereby reducing or preventing ORC pump cavitation caused by vapor bubbles.
- ORC working medium is split into two flows
- the flow downstream of the expander and is condensed by two different cooling media is strongly cooled with LNG as cooling medium.
- the flows are reconnected downstream of the condensers and the cooled flow is utilized to condense bubbles that are separated from the other, warmer flow.
- the method for reducing the risk for pump cavitation is an arrangement of cooling needs and heating needs in a way that enables selective cooling of the flow to the pump.
- the cold branch flow of the ORC working medium is mixed with the other branch flow of the ORC working medium in a location where bubbles are collected.
- the present invention is not a separate control system.
- the ORC working medium is split into two flows so that one of the flows is vaporizing LNG and heating up the vapor from LNG.
- the heat exchanging with LNG makes it possible to cool one of the ORC medium flows to temperatures close to LNG temperature.
- the very cold ORC working medium flow is utilized for selective cooling and condensing of bubbles in addition to cooling of the flow to the pump.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NO20121329A NO334873B1 (en) | 2012-11-12 | 2012-11-12 | Modified Organic Rankine Cycle (ORC) process |
PCT/NO2013/050187 WO2014073975A1 (en) | 2012-11-12 | 2013-11-06 | A modified organic rankine cycle (orc) process |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2923044A1 true EP2923044A1 (en) | 2015-09-30 |
EP2923044A4 EP2923044A4 (en) | 2016-11-09 |
Family
ID=50684953
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13853630.5A Withdrawn EP2923044A4 (en) | 2012-11-12 | 2013-11-06 | A modified organic rankine cycle (orc) process |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2923044A4 (en) |
NO (1) | NO334873B1 (en) |
WO (1) | WO2014073975A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108518288B (en) * | 2018-02-26 | 2020-05-29 | 上海海事大学 | ORC composite power generation system suitable for LNG hybrid power ship |
CN109595131A (en) * | 2019-01-17 | 2019-04-09 | 苏州良造能源科技有限公司 | A kind of solar energy optical-thermal and natural gas cold energy combined power machine electricity generation system |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4437312A (en) * | 1981-03-06 | 1984-03-20 | Air Products And Chemicals, Inc. | Recovery of power from vaporization of liquefied natural gas |
US6986251B2 (en) * | 2003-06-17 | 2006-01-17 | Utc Power, Llc | Organic rankine cycle system for use with a reciprocating engine |
US7174732B2 (en) * | 2003-10-02 | 2007-02-13 | Honda Motor Co., Ltd. | Cooling control device for condenser |
US7900451B2 (en) * | 2007-10-22 | 2011-03-08 | Ormat Technologies, Inc. | Power and regasification system for LNG |
FR2935737B1 (en) * | 2008-09-10 | 2013-02-15 | Suez Environnement | IMPROVED COGENERATION DEVICE |
FR2939877A1 (en) * | 2008-12-16 | 2010-06-18 | Air Liquide | Downstream vapor condensation method for steam turbine utilized to drive e.g. air compressor, involves carrying out condensations of two vapor parts simultaneously at same pressure i.e. sub-atmospheric pressure |
JP5338730B2 (en) * | 2010-03-29 | 2013-11-13 | 株式会社豊田自動織機 | Waste heat regeneration system |
KR101152254B1 (en) * | 2010-08-05 | 2012-06-08 | 한국에너지기술연구원 | ORC system for preventing cavitation of pump |
WO2012024683A1 (en) * | 2010-08-20 | 2012-02-23 | Icr Turbine Engine Corporation | Gas turbine engine with exhaust rankine cycle |
-
2012
- 2012-11-12 NO NO20121329A patent/NO334873B1/en not_active IP Right Cessation
-
2013
- 2013-11-06 EP EP13853630.5A patent/EP2923044A4/en not_active Withdrawn
- 2013-11-06 WO PCT/NO2013/050187 patent/WO2014073975A1/en active Application Filing
Also Published As
Publication number | Publication date |
---|---|
WO2014073975A1 (en) | 2014-05-15 |
EP2923044A4 (en) | 2016-11-09 |
NO334873B1 (en) | 2014-06-23 |
NO20121329A1 (en) | 2014-05-13 |
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Legal Events
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AX | Request for extension of the european patent |
Extension state: BA ME |
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RA4 | Supplementary search report drawn up and despatched (corrected) |
Effective date: 20161011 |
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RIC1 | Information provided on ipc code assigned before grant |
Ipc: F01K 15/04 20060101ALI20161005BHEP Ipc: F01K 25/08 20060101ALI20161005BHEP Ipc: F01K 23/10 20060101ALI20161005BHEP Ipc: F02C 1/04 20060101ALI20161005BHEP Ipc: F01K 23/04 20060101ALI20161005BHEP Ipc: F01K 23/02 20060101ALI20161005BHEP Ipc: F01K 23/06 20060101AFI20161005BHEP Ipc: F02C 6/18 20060101ALI20161005BHEP |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20200603 |