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
  • 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
  • F01K25/06—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 mixtures of different fluids
  • F01K25/065—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 mixtures of different fluids with an absorption fluid remaining at least partly in the liquid state, e.g. water for ammonia

Definitions

• the present invention relates to a method for providing a work performing device with a working fluid and in particular a working gaseous fluid, e.g. a fluid at a temperature and pressure suitable for driving a turbine for the generation of electricity, or for the movement of fluids or solids by entrainment or the enhancement of oil field recovery by inflation or pressurisation with fluids.
• a working gaseous fluid e.g. a fluid at a temperature and pressure suitable for driving a turbine for the generation of electricity, or for the movement of fluids or solids by entrainment or the enhancement of oil field recovery by inflation or pressurisation with fluids.
• working fluid as used in the accompanying description of the invention includes fluids which may be said to possess a potential to do work, for example, fluids which possess a temperature and/or pressure which are thereby a potential source of energy which may be exploited to do work.
• CO 2 carbon dioxide
• water vapour ammonia
• organic hydrocarbons organic hydrocarbons
• halogenated hydrocarbons organic hydrocarbons
• polyhalogenated hydrocarbons polyhalogenated hydrocarbons
• the present invention provides a method for providing a work performing device with a working fluid having a temperature ToK and a pressure P bar in which the said working fluid at a temperature less than ToK and a pressure less than P bar is exposed to a sorbent material (as defined) which is subsequently heated together with the said working fluid at substantially constant volume to give the said working fluid a temperature ToK and a pressure P bar.
• work performing device includes devices which inflate or increase the pressure of a region or enclosure by means of a fluid.
• sorbent material is used to describe a range of materials that may be further described as adsorbents or persorbents. Examples of these materials and the manner in which they behave is described in US Patent 4 327 553.
• persorbents are generally preferred and specifically there may be mentioned dehydrated zeolites and emergent adsorbents.
• the method of the present invention may be exploited in a cycle of events as follows. A working fluid at, e.g. ambient temperature and pressure is exposed to a sorbent material, also at ambient temperature, and allowed to reach equilibrium therewith.
• the term "exposed” means briging together so as to allow union between the said working fluid and the said sorbent.
• the pressure of the working fluid may be increased during sorption to increase the amount thereof "taken up” by the sorbent. Under these circumstances a considerable quantity of working fluid may be sorbed.
• the temperature of the sorbent together with the working fluid is then raised while at substantially constant volume (i.e. while the sorbent and working fluid are held in a closed environment). As the temperature rises the sorbent progressively desorbs so as to release some of the working fluid and the pressure of working fluid in the system increases. Thus, the system becomes a potential source of energy by virtue of the presence of hot, pressurised working fluid.
• the final temperature and pressure of the working fluid it may be fed directly to a turbine for the generation of electricity. In doing work the temperature and pressure of the working fluid will fall, but the cycle may be repeated by exposing the working fluid to further sorbent material.
• this whole process may be lowered in temperature range, for example, by enclosing the major artefacts of the system in a chamber which is (a) substantially insulated from the surroundings (barring any necessary supply of heat from the surroundings or rejection to the surroundings), and (b) initially refrigerating the relevant components within the chamber to the desired sub-ambient temperature, it being apparent that this initial refrigeration will only need "topping-up" relatively infrequently depending upon the imperfection of the recuperative process described in Figure 2 herein and associated text.
• the present invention also provides apparatus for supplying a work performing device with a fluid at an elevated temperature and pressure, the apparatus comprising a source of fluid, a chamber containing a sorbent for the fluid, heating means for heating the contents of the chamber, and control means, the control means being arranged to supply, fluid from the source to the chamber for sorption by the sorbent, to retain the fluid and sorbent in the chamber and to cause the heating means to heat both fluid and sorbent while retained therein, thereby to raise the fluid to an elevated pressure and temperature, and to release the fluid at its elevated temperature and pressure from the chamber and to supply it to the work performing device.
• FIG. 1 represents diagrammatically a temperature (T) /entropy (S) cycle for a working fluid such as as CO 2 .
• Persorbent material such as a dehydrated crystalline sodium alumino-silicate, in close-packed pellet or granule form, loaded into a connected series of shell and tube heat exchangers, is exposed at a temperature of 273°K to gaseous CO 2 also at 273oK while the pressure of the CO 2 is increased by, for example, conventional means from 1.1 (point F) to 60 (point B) bar.
• the ratio of sorbent material to CO 2 by weight may conveniently be 5 to 1.
• the CO 2 is rapidly sorbed until equilibrium is reached, with a corresponding decrease in the entropy of the CO 2 and a rise in the temperature of the persorbent to approximately 300°K (point B).
• the amount of CO 2 which is sorbed may approach 0.5 g CO 2 per cc of persorbent. If the temperature of the persorbent is then increased, e.g. by heating by conventional or emergent means with a heat transfer fluid, while the persorbent and CO 2 are held at substantially constant volume (i.e. within a closed environment), CO 2 will be driven off from the persorbent and its pressure will rise until at a temperature of, for example 450oK, the pressure of CO 2 will have reached about 230-400 bar (point C).
• Hot, pressurised CO 2 is thus available as a working fluid, and if released through a pressure control valve, at for example 90-100 bar (point D) may be made to perform work, for example by driving the blades of a turbine for generating electricity.
• the CO 2 may continue to perform work by expansion until either its temperature and pressure fall to the cycle starting point F (273oK, for example 1.1 bar) when the cycle may be repeated, or to some point E, below 273°K, (e.g. 200 °K at 1.3 bar by means of a turbine of higher isentropic efficiency) when either the same cycle (EBCD) may be repeated starting from a lower temperature or advantage may be taken of the circumstances to operate in addition an air-conditioning stage (EF).
• F temperature and pressure fall to the cycle starting point F
• E below 273°K, (e.g. 200 °K at 1.3 bar by means of a turbine of higher isentropic efficiency) when either the same cycle (EBCD) may be repeated starting from a lower temperature or advantage may be taken of the
• the (cold) CO 2 When an air conditioning cycle is operated the (cold) CO 2 is used to cool the ambient air, and as a result the temperature of the CO 2 will increase (at substantially constant pressure) until either it approaches the temperature of ambient air or is removed from the air-conditioning cycle (point F), when it may be re-introduced into the persorbent cycle (BCDEFB).
• the combination of persorbent and air conditioning cycles may be particularly valuable in, for example, an office block, requiring both electricity and an air-conditioning system. In such an instance, persorption would normally take place during the night with desorption commencing at, e.g. 7 am, when electricity, heating and cooling are required jointly or severally.
• heat present in the desorbed sorbent material must be retained in the system, and preferably used to increase the temperature of the freshly sorbed material. This may be achieved by means of the recuperative mechanism shown in Figure 2 of the accompanying drawings.
• the persorbent material after loading into a series of shell and tube heat exchangers may be exposed to CO 2 and subsequently heated.
• the temperature of the persorbent prior to exposure may be 273oK (units 1-6).
• the temperature of the remaining persorbent material may be 433°K (units A-F).
• exchangers 1-6 may be heated to a temperature approaching 433oK at the expense of the exchangers A-F.
• connection between the heat exchangers of the same series is thermally poor and includes a suitable valve arrangement for the isolation of each exchanger.
• the present Invention also provides a method for transferring heat from material at an initial temperature T 1 held in a number of connected heat exchangers in a first series to material at an initial temperature T 2 held in a number of connected heat exchangers in a second series in which by heat transfer means between each and every one in turn of the exchangers in the said first series with each and every one in turn of the exchangers in the said second series heat may be transferred in discrete stages from the said material at said initial temperature T 1 to the said material at said initial temperature T 2 so that the final temperature of the said material in the said first series substantially approaches T 2 and the final temperature of the said material in the said second series substantially approaches T 1 .
• the invention provides a method wherein the said heat transfer means between the said exchangers in each said series are arranged so that each said exchanger in turn and in a first fixed sequence in the said first series reaches an equilibrium temperature successively with each said exchanger in turn and in a second fixed sequence in the said second series thus transferring most of the beat from the said material held in the said first series of exchangers to the said material held in the said second series of exchangers in the said discrete stages.
• the present invention provides apparatus for transferring heat from material at an initial temperature T 1 held in a number of connected heat exchangers in a first series to material at an initial temperature T 2 held in a number of connected heat exchangers in a second series comprising heat transfer means between each and every one in turn of the exchangers in the said first series with each and every one in turn of the exchangers in the said second series in order that heat may be transferred in discrete stages from the said material at said Initial temperature T 1 to the said material at said initial temperature T 2 so that the final temperature of the said material in the said first series substantially approaches T 2 and the final temperature of the said material in the said second series substantially approaches T 1 .
• the Invention provides apparatus wherein the said heat transfer means between the said exchangers in each said series are arranged so that each said exchanger In turn and in a first fixed sequence in the said first series reaches an equilibrium temperature successively with each said exchanger in turn and in a second fixed sequence In the said second series thus transferring most of the heat from the said material held in the said first series of exchangers to the said material held In the said second series of exchangers in the said discrete stages.
• recuperative methods may be employed, e.g. where the heat exchangers are arranged in a continuous circle.
• a sorbent material as described above it is possible (i) to reduce the entropy of the working fluid without cooling, (ii) to increase the temperature of the working fluid at substantially constant volume, and (iil) to desorb the sorbent material isothermally, by providing much of the heat input at the highest cycle temperature during desorption, thus improving cycle efficiency.
• Figure 3 illustrates a practical selfexplanatory flow diagram embodying the present invention based on the temperature/entropy cycle of Figure 1 in combination with the recuperative mechanism of Figure 2, when employing CO 2 as a working fluid.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Separation Of Gases By Adsorption (AREA)

Applications Claiming Priority (4)

Publications (1)

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• 1984
  • 1984-08-20 AU AU32183/84A patent/AU3218384A/en not_active Abandoned
  • 1984-08-20 IT IT8422361A patent/IT8422361A0/it unknown
  • 1984-08-20 DD DD84266447A patent/DD223497A5/de not_active IP Right Cessation
  • 1984-08-20 WO PCT/GB1984/000290 patent/WO1985000852A1/en unknown
  • 1984-08-20 EP EP84903082A patent/EP0153359A1/de not_active Withdrawn

Non-Patent Citations (1)

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