Classifications

• • 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
  • F01K13/00—General layout or general methods of operation of complete plants
• • 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 invention relates to a thermodynamic system, in particular a system implementing a thermodynamic Rankine cycle.
• Said pump has the function of creating a pressure difference within the system, and to ensure the circulation of a working fluid within said system.
• Said condenser has the function of liquefying the working fluid before it enters into communication with said pump.
• Such pumps are likely to be deteriorated, in particular by cavitation. Therefore, a protection of said pump is to be expected.
• the NPSH - net positive suction head in English - measures the difference between the pressure of the liquid at a point in the thermodynamic system and the saturation vapor pressure at the temperature of the working fluid. Cavitation in a pump appears if the fluid pressure passes locally below the vaporization pressure of said fluid, so if the NPSH is too low.
• One of the objectives of the invention is to avoid the phenomenon of cavitation of a pump intended to be integrated in a thermodynamic system, in particular with the aid of a simplified solution.
• thermodynamic system in particular a system implementing a Rankine thermodynamic cycle, comprising a circulation loop of a working fluid, said loop comprising a pump intended to increase the pressure of said working fluid when it is in the liquid phase and a condenser for condensing said working fluid upstream of said pump when said working fluid is in the gas phase.
• said loop further comprises a regenerator, said regenerator being positioned in a part of the loop configured for the circulation of the fluid in the liquid phase, said regenerator being configured to exchange thermal energy between said working fluid in downstream of said condenser and said working fluid downstream of said pump, said regenerator being adapted to lower the temperature of said working fluid upstream of said pump, said loop further comprising a heat exchanger for lowering the temperature of said working fluid downstream of said regenerator, said heat exchanger being connected in series between said regenerator and said pump.
• the invention consists in cooling the working fluid after it has been condensed, in particular to ensure the absence of any traces of fluid in the gaseous state before it enters the pump and n causes it to deteriorate.
• regenerator is mounted on the one hand, between said condenser and said heat exchanger and on the other hand, between said pump and an evaporator, said evaporator being configured to evaporate the working fluid when it is in the liquid phase,
• the system of the invention comprises a circulation loop for a cooling fluid, the condenser and the heat exchanger being traversed by said cooling fluid,
• said loop for circulating a cooling fluid is configured on the one hand for liquefying the working fluid through said condenser and, on the other hand, for cooling said working fluid through said heat exchanger,
• the system of the invention comprises two circulation loops for two cooling fluids, the condenser being traversed by one of said two cooling fluids and the heat exchanger being traversed by the other of said two cooling fluids,
• said circulation loops of said two cooling fluids are configured on the one hand to liquefy the working fluid through said condenser and on the other hand for cooling said working fluid through said heat exchanger.
• FIG. 1 is a schematic representation of an embodiment of a system according to the invention
• FIG. 2 is a diagram illustrating an example of fluid temperatures in a system according to the invention, in particular that illustrated in FIG.
• thermodynamic system 10 in particular a system 10 implementing a thermodynamic Rankine cycle.
• This system 10 comprises a circulation loop 21 -26 of a working fluid.
• Said loop will advantageously comprise a power generation means (not shown here).
• Said energy production means will advantageously comprise a turbine.
• Said turbine is intended to be driven by the expansion of said working fluid in the gas phase.
• said power generation means may advantageously comprise an electric energy generator coupled to said turbine.
• said loop 21 -26 will comprise a first section (not shown here), in which circulates the working fluid in the vapor state, high temperature and high pressure.
• This first section drives the working fluid to the turbine, through which it relaxes, while driving the turbine in a rotational movement, movement advantageously transmitted to the generator via a transmission shaft.
• said working fluid flows from the condenser 30 to a pump 40, in particular via a first succession of sections 23, 24, 25. Said working fluid is then in the liquid state, low temperature and low pressure. After passing through said pump 40, the working fluid is still in the state of liquid, low temperature but at high pressure.
• said loop 21 -26 advantageously comprises a heat exchanger 50 intended to lower the temperature of said working fluid downstream of said condenser 30, said heat exchanger 50 being connected in series between said condenser 30 and said pump 40.
• said heat exchanger 50 is positioned at the first succession of sections 23, 24, 25, wherein said working fluid is in the liquid state, low temperature and low pressure. More specifically, said heat exchanger 50 is positioned between sections 24 and 25; it makes it possible to reduce the temperature of said working fluid, downstream of the condenser 30 and upstream of the pump 40, for example by a few degrees Celsius.
• the term "a few degrees Celsius” means a number less than 25 ° C, for example a figure substantially of the order of 5 ° C.
• said fluid first passes through a regenerator 60 before being driven, via the intermediate section 24, to said pump 40.
• said loop 21 -26 advantageously comprises a regenerator 60 positioned in a part of the loop configured for the circulation of the fluid in the liquid phase, between the sections 23 and 24, but also between the sections 26 and 21.
• Said regenerator 60 is configured to exchange thermal energy between said working fluid upstream of said heat exchanger 50 and said working fluid downstream of said pump 40.
• the objective of using said regenerator 60 is the lowering the temperature of said working fluid upstream of the pump 40, in particular upstream of said heat exchanger 50, so as to increase the NPSH mentioned in the preamble.
• said regenerator 60 is mounted between the condenser 30 and the heat exchanger 50, thus between the sections 23 and 24.
• the exchanger 50 is connected in series between the regenerator 60 and the pump 40.
• Said regenerator 60 is also mounted between said pump 40 and an evaporator (shown above but not shown here), thus between sections 26 and 21 of FIG.
• Said regenerator 60 therefore makes it possible to exchange thermal energy between said working fluid when it is in the liquid phase upstream of the pump 40, more precisely upstream of the heat exchanger 50, and said working fluid when it is in the liquid phase, downstream of said pump 40.
• regenerator 60 can advantageously be described as an internal exchanger.
• the lowering of the temperature in said heat exchanger 50 makes it possible to ensure a temperature difference between the two sides of the regenerator 60 to allow heat exchange and thus lower the temperature of the working fluid between the outlet of the condenser 30 and the inlet of the pump 40.
• the regenerator 60 makes it possible to reduce the temperature of the working fluid between the condenser 30 and the pump 40. This reduction will advantageously be of the order of a few degrees Celsius, preferably of the order of a few tens of degrees Celsius.
• the term "a few tens of degrees Celsius” means a number between 10 ° C and 50 ° C.
• regenerator 60 thus participates in the protection of the pump by avoiding all the more the risk of cavitation of the latter.
• said regenerator 60 makes it possible to increase said NPSH by further decreasing the temperature of said working fluid at its inlet.
• An advantage of the system according to the invention therefore lies in the fact that the working fluid is cooled before entering the pump 40 so as to avoid any deterioration thereof, in particular by cavitation.
• the working fluid will have to be reheated after passing through the pump to be evaporated. It would be counterproductive to cool it unduly before it passes into the pump 40 and then have to heat it up to evaporation, which is not the case of subcooling obtained here through said regenerator 60.
• the system 10 of the invention will advantageously be configured so that:
• said toluene is cooled through the regenerator 60 to be measured at its outlet at around 29 ° C., in particular in section 24 of FIG. 1, and in such a way that
• said toluene is cooled through the heat exchanger 50 to be measured at its outlet at around 26 ° C., in particular in section 25 of FIG.
• the pump 40 will then compress said toluene, for example to 15bar, and the regenerator 60 will then heat up to about 63.4 ° C.
• the condenser 30 is connected to a first cooling circuit 71 -73 which comprises at least one cold source (not shown here); said cooling circuit 71 -73 is advantageously a circuit external to the loop 21 -26.
• heat exchanger 50 is also in connection with a cooling circuit, which circuit may be independent of said first cooling circuit 71 -73 (case not shown here).
• the condenser 30 and the heat exchanger 50 are traversed by the same cooling fluid.
• the condenser 30 and the heat exchanger 50 are advantageously connected to the same cooling circuit 71 -73.
• Said circulation loop 71 -73 of a cooling fluid is here configured, on the one hand for liquefying the working fluid through said condenser 30 and, on the other hand for cooling said working fluid through said heat exchanger. 50.
• Said single 71 -73 circulation loop simplifies the integration of the system 10 of the invention, for example on site.
• FIG. 2 illustrates an example of temperatures measured, in the context of the example of the system of FIG. 1, for the working fluid on the one hand, and for the cooling fluid on the other hand, especially in the case where the condenser 30 and the heat exchanger 50 are traversed by the same cooling fluid.
• This FIG. 2 comprises a first curve C1 which represents the evolution of the temperature of the working fluid within the thermodynamic system of the invention.
• This curve C1 shows the effects on the temperature of the working fluid:
• regenerator 60 upstream of the pump 40 namely a drop of approximately 30 degrees Celsius
• the heat exchanger 50 also upstream of the pump 40, namely a drop of a few degrees Celsius
• FIG. 2 also includes a second curve C2 which represents the evolution of the temperature of a said cooling fluid within the cooling loop 71 -73 illustrated in FIG.
• This curve C2 shows the variations in the temperature of said cooling fluid:
• the system 10 of the invention therefore makes it possible to favor a thermal height rather than a geometrical height of pressure, in particular to increase the NPSH of the pump 40.
• the system 10 of the invention therefore proposes an easy solution to implement, on site for example.
• favoring a geometric pressure height to increase the NPSH of the pump 40 entails strong integration constraints; for example burial constraints of the pump over several meters, or constraints of elevation of the condenser relative to the pump.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Engine Equipment That Uses Special Cycles (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (3)

Family Cites Families (3)

• 2015
  • 2015-12-01 FR FR1561694A patent/FR3044351B1/fr not_active Expired - Fee Related
• 2016
  • 2016-10-18 EP EP16782071.1A patent/EP3384136A1/de not_active Withdrawn
  • 2016-10-18 WO PCT/EP2016/074921 patent/WO2017092922A1/fr not_active Ceased

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