Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B23/00—Heating arrangements
  • F26B23/001—Heating arrangements using waste heat
  • F26B23/002—Heating arrangements using waste heat recovered from dryer exhaust gases
  • F26B23/004—Heating arrangements using waste heat recovered from dryer exhaust gases by compressing and condensing vapour in exhaust gases, i.e. using an open cycle heat pump system
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23K—FODDER
  • A23K10/00—Animal feeding-stuffs
  • A23K10/20—Animal feeding-stuffs from material of animal origin
  • A23K10/22—Animal feeding-stuffs from material of animal origin from fish
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23K—FODDER
  • A23K30/00—Processes specially adapted for preservation of materials in order to produce animal feeding-stuffs
  • A23K30/20—Dehydration
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF
  • A23L17/00—Food-from-the-sea products; Fish products; Fish meal; Fish-egg substitutes; Preparation or treatment thereof
  • A23L17/10—Fish meal or powder; Granules, agglomerates or flakes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
  • Y02B30/52—Heat recovery pumps, i.e. heat pump based systems or units able to transfer the thermal energy from one area of the premises or part of the facilities to a different one, improving the overall efficiency
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

• the invention is related to the drying of fish meal or the like in a plant comprising an indirectly heated drier.
• the invention also pertains to a plant capable of excercisirg the method.
• the drier may be a directly heated drier in which hot and relatively dry air, is directed through or over the material to be dried.
• the drier may be an indirectly heated apparatus in which the necessary heat (enthalpi) for evaporation of the humidity in the material treated is transferred through a heat exchange surface by heat transmission from a chamber for the heating- means, e.g. steam to a drying chamber for the material to be dried.
• Plant may be constructed that way, that the drying is carried out by successively passing the material through at least two driers, which each may be directly heated or indirectly heated.
• This invention is related to a drying plant comprising an indirectly heated drier and eventually an evaporator (a stickwater plant), which are indirectly heated, and in which the heating take place by means of steam.
• This invention is distinctive in teaching application of a mainly adiabatic heating of the steam generated in an indirectly heated drier (evaporater) until reaching a temperature which is the minimum temperature requested for the heating medium used in the indirectly heated drier/evaporator, which produced the steam to be compressed, and the use of this steam as the heating medium in the drier/evaporator.
• the energy saving is not only easily calculable but it is basically possible to carry it into effect.
• the pecularity that steam generated in the drier after compression is utilised as heating means in the drier is an advantage especially as the drier is usually a substantial or main enthalpi consumer in the plant.
• a plant comprising a cooker, a multi-step evaporator and a drier is often allocating about one third of the heat consumption to each of the three units.
• the drier is requiring the highest temperature, a fact that makes the feeding of this unit with inexpensively generated steam extremely interesting.
• the method of the invention may be distinctive in the use of enthalpi in condensate generated from the compressed steam by piping this condensate from the drier to the cooker in which it is in an in itself well-known way used as a heating medium.
• the advantage is saving of specially heated water otherwise necessary for heating the cooker.
• a special and in itself well-known embodiment of the cooker is utilising both the condensate as well as the steam as heating medium, and it is designed in order to utilise the steam only in that part of the cooker holding the highest temperature range. It is an advantage, too, if the cooker is designed to apply the counter-current principle in the movement of the heating medium and the material to be heated relatively to one another on each side of the heat exchange surface.
• the invention may in an embodiment be distinctive in the cooling of the overheated compressed stem to or slightly above the saturation point at the compression pressure.
• This cooling is preferably carried out by injection of a controlled quantity of condensate generated in the drier and/or in the evaporator if the plant comprises an evaporator.
• the steam is heated by compression in two or more steps, and during at least one intermediate step the overheated steam is cooled to a temperature only slightly above the point of saturation for steam at the pressure reached.
• the advantage is that the following compression step(s) can be carried out at a lower temperature than otherwise necessary and possibly too high to economically acceptable control and handling.
• saturated or nearly saturated steam rather than overheated steam.
• Another advantage in using at least two compression steps is, that an evaporator in a plant should often be supplied with steam inferior in pressure and temperature to the steam required to feed the drier. The above mentioned embodiment in this case makes the saving of unnecessary compression possible by allowing branching off a stream of steam between the steps of compression.
• the compression may be carried out in one or more steps, and cooling of steam and/or branching off of steam streams may take place in between two steps of compression and/or after the final compression.
• the advantage related to such a steam compression design is an increa- sed flexibility and an increase in possibilities regarding the control of the entire heat economy of the plant.
• the method according to the invention may finally be distinctive by a starting up procedure comprising gene- ration of steam by means of steamgeneration means located in the means for cooling the overheated, compressed steam, steam piping means for piping the first generated steam back to the steam compression means via pressure reduction means, utilising the first generated steam exceeding the normal steam comsumption of the steam compression means for heating cold condensate or start—up feed water in the plant, and when the apparatus (es) in the plant requesting the relatively lowest temperatures du ring production has reached their production temperatures, then leading steam in excess of this need as a heating medium to the indirectly heated drier(s) /evaporator(s), and finally when the steam generating appara- tus(es) in the plant produces sufficient steam, closing down for the piping of steam from the steam cooling means to the steam compression means, and the steam generation means located in the steam cooling means, are shut down and kept unproductive as long time, as steam is produced in the drier(s)/evaporator(s) in sufficient quantity.
• the invention is describing a plant for production of fish meal or a similar product, and comprising an indirectly heated drier, the plant being capable of practising the method invented.
• the plant is peculiar by comprising at least one compressor, steam piping means connecting the suction side of this compressor with the drying chamber in the drier and steam piping means connecting the pressure side of the compressor with the chamber for heating means in the drier.
• the advantage related to this plant is, that it can perform the method invented and realize the advantages listed above.
• a drying plant according to the invention may be peculiar by comprising a boiler or heater designed with at physical separation between the heating medium and the material to be heated, and too comprising piping means for condensate leading hot, condensated steam produced by compression of drying steam/evaporation steam and utilised as a heating medium in the drier/evaporator from the steam condensing apparatus to the boiler/heater.
• the advantage gained by this design is, that it makes a specials advantageous reuse of the enthalpi in the dryingsteam possible .
• the drier according to the invention and comprising more than one steam producing apparatus may further be peculiar by comprising steam piping means converging the different streams of steam generated in the different drier(s) and/or evaporator(s) to one main stream of steam.
• the means for uniting two or more minor streams of steam may be placed in upstream direction in relation to a first compressor , or one or more of the different streams of steam may be compressed, before the flow of these streams joins.
• a plant according to the invention maytoo be peculiar by comprising steam cooling means capable of cooling the steam heated by compression and therefore being an overheated steam to a temperature close to or being the temperature creating saturated steam by the pressure reached by the compression.
• the steam cooling means may be peculiar by having injection means for injection of a controlled quantity of condensate from the drier or the evaporator in the overheated steam.
• substantially saturated heat instead of overheated steam is, that the temperature on the heat transfer surfaces to be heated by means of the steam in an easier way can be constant uniform and on the desired level.
• the advantaged related to the injection means system is, that it's inexpensive, simpel and reliable, and the steam quality is not either changed.
• the plant according to the invention may further be peculiar by comprising steam compression means involving more than one compression step and by at least one step in between two compression steps involving steam cooling means and/or steam branching off means preferably placed immediately down-stream in relation to the following compression step.
• the steam branching off means may be equipped with steam valving means making it possible to control the flow in the branched off stream of steam.
• Plant accordingto the invention arid comprising steam cooling means placed down-stream after the steam compression means and up-stream in relation to the drier/ evaporator may finally be peculiar by having the steam cooling means comprising steam generation means e.i. in form of electrical heating elements installed in the lower section of the steam cooling means, where condens water/start-up feed water is collected, steam piping means including pressure reduction means and steam valving means designed to feed steam directly from the steam cooling means to the steam comp ression means after a pressure reduction or to alternatively block such steam passage, and steam piping means including valving means and capable of feeding steam from the steam cooling means to heating means for condenswater/start-up feed water and capable of blocking such steam passage.
• steam cooling means comprising steam generation means e.i. in form of electrical heating elements installed in the lower section of the steam cooling means, where condens water/start-up feed water is collected
• steam piping means including pressure reduction means and steam valving means designed to feed steam directly from the steam cooling means to the steam comp
• fig. 1 a diagram schematically illustrating a fishmeal plant according to the invention and of very simple structure
• fig. 2 an enthalpi diagram illustrating the content of enthalpi in 1 kilo steam (water) at several locations and different states
• fig. 3 a diagram similar to fig. 1, but a plant according to the invention of more complicated structure
• fig. 4 an enthalpi diagram similar to fig. 2, but illustrating content of enthalpi in 1 kilo steam/water at locations and states of matter related to the plant according to fig. 3.
• fig. 1 is illustrated an indirectly heated drier 1, an indirectly heated cooker 2, a decanter 3 , steam compression means 4, steam piping means 13 for drier generated steam and steam piping means 15 for compressed steam.
• Pig. 1 further illustrates the raw material supply conduit 5, a conduit 6 for boiled rawmaterial leading to the decanter 3 , a conduit 7 for fish-oil a stickwater conduit 9 and a conduit 8 for decanted fish-material.
• the plant further comprises a pump 22 for fish-material, a conduit 10 for fish material.
• Condensate piping means 19 is connecting the outlet opening l ⁇ for condensate in the drier 1 and inlet opening 20 for heating means in the cooker 2.
• the outlet opening 21 for used heating means in the cooker 2 is by means of a conduit 22 connected to the sewer.
• the plant described above functions as follows: via the conduit 5 for rawmaterial is cold (normally about 5°C) rawmaterial pumped to the cooker 2.
• the heating normally bringing the rawmaterial to the boiling point.
• the conduit 6 Through the conduit 6 is the boiling hot fish material pumped to the decanter 3, in which the oil and stick- water are separated from the solid and semisolid matters.
• the oil is pumped through the conduit 7 for fishoil and leaving the plant as "raw fishoil".
• the solid and semisolid matters and the stickwater are via the conduits 8 respectively 9 and the pump 22 pumped via the conduit 10 to the drier 1.
• the drier 1 In the drier 1 is the water/humidity in the fish material dried out by means of indirectly heating provided by condensating steam.
• the dried matter is leaving the drier via the fish meal outlet opening 11, whereas the generated steam is taken out via the steam outlet opening 12 and via the conduit 13 fed to the suction side if the steam compressor 4.
• After compression to the pressure required for condensation at the minimum heating temperature in the drier 1 is the steam via the compressor outlet 14 and the conduit 15 fed to the inlet opening 16 for heating means in the drier 1 in order to function as heating medium.
• Auxiliary steam may be supplied via conduit 17 especially during start-up of the plant.
• the auxiliary steam is generated in the steam generator not shown in the drawing.
• the condensate generated in the drier 1 is via the outlet 18 and the conduit 19 fed to the inlet opening 20 in the cooker in order to function as heating means for heating the rawmaterial.
• a flow (in counter-current configuration relative to the fish material) in the cooker 2 is the condensate leaving the cooker via the outlet opening 21 and is via the conduit 22 directed towards the sewer.
• the plant is a combination of units, all of which are well known except for the piping of the steam produced in the drier 1. We therefore underline,that this steam is piped directly into a conventional compressor, in which it is compressed to the pressure necessary to make the steam useful as feed steam in the drier 1.
• the steam is after the compression piped to this drier 1, and the enthalpi content in the steam can thus be reused in the drier in an advantageous way .
• Fig. 2 is an enthalpidiagram indicating the enthalpi content in one kilo of water included in the raw- material supplied to the plant at 5°C This water is heated to the boiling point in the cooker 2 under absorption of 419 kJ.
• the drier 1 is further enthalpi supplied and absorbed under generation of 1 kilo of steam at 1 bar pressure and 100°C having an enthalpi content of 2676 kJ.
• the compressor 4 is another 162,5 kJ enthalpi (converted free energy) supplied to the 1 kilo of steam.
• the residual enthalpi is to a large extent utilised in the cooker 2, where the condensate is cooled from 126°C to 15°C before flowing to the sewer.
• Fig. 3 is illustrating a more complicated plant for production of fishmeal according to the invention.
• the plant comprises the main components comprised in the plant according to fig. 1.
• fig. 3 are the reference figures for the drier 101, the cooker 102 and the decanter 103.
• the plant further comprises a buffertank 104 for hot condensate and a stickwater evaporator 105.
• the compressor in the plant according to fig. 1 is in the more sophisticated plant illustrated in fig. 3 replaced by two compressors 106, 108 coupled in succession.
• the plant illustrated in fig. 3 and the plant illustrated in fig. 1 are according to the invention utilising the very same main principle for the main supply of enthalpi.
• the following description of how the plant in fig. 3 functions, is therefore mainly mentioning the differences between the two plants.
• the stickwater is piped from the decanter 103 via the pipe 114 to the evaporator 105, in which it is concentrated to a stickwater concentrate, before its piped via pipe 118 and 116 to the drier 101 joining the non -fluid fish components.
• the steam generated in the evaporator 105 is piped via pipe 121 to pipe 120, through which it joining the steam leaving the drier 101 and fed to this point through pipe 119 is piped to the compressor 106.
• the steam compressed in the compressor 106 is piped through pipe 122 to the cooler 107, in which a controlled amount of condensate is injected transforming the steam to substantially saturated steam. Condensate is fed to the cooler via pipe 132, 134 and 135 from the stickwater evaporator 105.
• the other part of the steam is piped via pipe 125 to the second compressor 108.
• this compressor is the steam piped via pipe 126 to cooler 109, in which it by means of condensate fed to the cooler via pipe 132, 134 and 136 is transformed to saturated steam.
• This steam is via pipe 128 fed to the drier 101.
• Surplus df steam may via pipe 129 and controlled by valve 130 be fed to the condenswater tank 104.
• Condensate from as well the drier as the evaporator is fed to the condenswater tank 104 via pipe 131 respectively 132, 133.
• the condensate is utilised as heating medium in the cooker 102.
• the drain pipe 138 for heating medium leaving the boiler 102 is branched off in one pipe 139 feeding the heating medium back to the condens- water tank 104, and another branch 140 leading to the sewersystem.
• Fog. 4 is an enthalpi/pressure diagram of state illustrating 1 kilo of water moving its way through the plant .Starting at the inlet to the drier or the evaporator this water is containing 419 kJ enthalpi. During evaporation another 2, 257.1 kJ enthalpi is absorbed,and the steam now containing 2,676.1 kJ is fed to the compressor 106 in which further 162.4 kJ enthalpi is supplied (in the form of free energy). The pressure hereby is increased to 2.4 bar, and the temperature is by now l85.3°C. In the cooler 107 is hot condensate from the evaporator 105 injected (approx. 5.5 per cent), and the steam is cooled to 126.1°C (or slightly higher). The slightly more than 1 kilo of steam now contains abt. 2.715 kJ of enthalpi.
• the condensate is piped from the drier 101 to the buffer tank 104 and is mixed with the condensate from the evaporator 105 and possibly other water supplied to this tank. Prom the tank the condensate is piped to the cooker and the contents of enthalpi utilised whereupon the cooled condensate is piped to the sewer.
• the temperature in the sewer outlet stream is usually held at 15°C (involving a loss of enthalpi of 60-65 kJ per kilo of dumped condensate).
• a preferred start-up procedure for a plant according to the invention and designed according to fig. 3 is following:
• auxiliary steam may be generated in a separate steam generator or in the cooler itself provided this is equipped with steam generating means e.g. electrically powered heating elements capable of evaporating water from the lower part of the cooler.
• the conduit 141 is open making a steam passage via pressure reduction means to conduit 120 and compressor 106 available.
• the steam generating means 106, 107. 108, and 109 may now start up yielding a reduced increasing steam generation.
• the valve sealing conduit 129 is released and condensate or feed-water in the buffer tank 104 is heated.
• water to the coolers 107 and 109 is taken from the buffer tank 104.
• the heating of the cooker 102 is the first thing to be done.
• auxiliary steam generating e.g. by electrically heated heating elements activated in cooler 107 as well as in the cooler 109 dependent on the over all design of the plant.
• the last apparatus in the plant to be heated during the start-up procedure is the drier.
• the consumption of energy in a plant according to the invention is analysed in the following example calculated based on production of fish meal prepared from 1,000 kilos of raw material which were old fish mainly the small atlantic species "lodde” or capelin (Mallotus villosus).
• the production was carried out in a plant as illustrated in fig. 3 and 4.
• the compressors were working at an efficiency of 67 per cent (not 100 per cent as indicated in fig. 4; we have noticed that compressors performing at efficiencies abt. 75 per cent are commercially available).
• the heat losses from the evaporator and the drier were 15 kW and 24 kW respectively and realized by only moderately insulated equipment. The performance calculated can therefore easily be improved.
• Heat consumption in the drier The heat treatment of 1,000 kilos of raw material in this case (treatment of old "lodde") and including the heating in the cooler, which were heated by means of condensate from the drier and the evaporator, called for a total energy supply of 74.6 kWh - which figure it is possible to further reduce.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Polymers & Plastics (AREA)
• Food Science & Technology (AREA)
• Zoology (AREA)
• Health & Medical Sciences (AREA)
• Marine Sciences & Fisheries (AREA)
• Animal Husbandry (AREA)
• Biomedical Technology (AREA)
• Biotechnology (AREA)
• Molecular Biology (AREA)
• Physiology (AREA)
• Nutrition Science (AREA)
• Sustainable Development (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Drying Of Solid Materials (AREA)

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• 1982
  • 1982-03-05 DK DK95982A patent/DK95982A/da not_active Application Discontinuation
• 1983
  • 1983-03-03 IS IS2789A patent/IS2789A7/is unknown
  • 1983-03-04 WO PCT/DK1983/000026 patent/WO1983003042A1/en not_active Ceased
  • 1983-03-04 EP EP83900836A patent/EP0103595A1/en not_active Withdrawn

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