Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/02—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
  • F26B21/04—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure partly outside the drying enclosure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B23/00—Heating arrangements
  • F26B23/02—Heating arrangements using combustion heating
  • F26B23/022—Heating arrangements using combustion heating incinerating volatiles in the dryer exhaust gases, the produced hot gases being wholly, partly or not recycled into the drying enclosure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B2200/00—Drying processes and machines for solid materials characterised by the specific requirements of the drying good
  • F26B2200/24—Wood particles, e.g. shavings, cuttings, saw dust

Definitions

• the invention relates to a dryer with exhaust gas purification thermal afterburning for water-moist bulk goods, such as B Wood chips, green fodder or similar organic particles, with cleaning of the Drying exhaust gases from organic pollutants and odors as well as from combustible fine dust due to thermal afterburning in the furnace the dryer as described in the preamble of claim 1.
• water-moist bulk goods such as B Wood chips, green fodder or similar organic particles
• the dryer works in a manner known per se with a return vapor line to return some of the vapors that come out of drying, back to the entry side of the drying apparatus and thus has one Vapor cycle on.
• An excess of vapor due to the Evaporation performance of the dryer and the outside of the vapor circuit incoming air is extracted from the vapor circuit.
• the dryer has its own furnace, consisting of a combustion chamber with at least one burner for burning gas, oil or fuel dust, which the extracted vapor stream is supplied as secondary air and thereby is heated to at least about 800 ° C to 850 ° C, so that the contained therein organic pollutants and odors burned as much as possible will.
• the dryer is not heated directly by supplying the hot ones Combustion gases in the drying apparatus, but it is the combustion gases heat is extracted in a gas / gas heat exchanger and transferred to the Vapor cycle released.
• the gas / gas heat exchanger if only because of its necessarily very massive construction and because of the poor thermal conductivity of the refractory compared to metal sheets Materials have a higher temperature difference from the heating side inlet to the outlet Cooling side and from the cooling side inlet to the heating side outlet has than that at exchangers made of sheet metal is the case. It is also disadvantageous that the Gas / gas heat exchanger that cannot be operated in direct current because otherwise the outlet temperature on the heating side will inevitably be higher than that outlet temperature on the cooling side would be temperatures of permits a maximum of approx. 400 ° C to approx. 500 ° C, so that the temperature load of the Wall between the heating and cooling sides does not damage them.
• the object of the invention is a dryer of the type mentioned above specify that allows at least the same efficiency of the Dryer, the gas / gas heat exchanger much easier and cheaper shape, and the firing temperature backed up so high allow the contained in the vapors fed to the furnace Harmful and odorous substances are burned reliably, with all vapors the furnace, as well as the exhaust air temperature of the dryer can be kept significantly lower than in previously described such systems.
• the dryer preferably has Rotary drum is designed to produce its own firing required drying heat, but the hot exhaust gases are not directly Dryer can be supplied for heating.
• the dryer works in known manner with vapor return, so that the drying apparatus and the return for vapors to the dryer inlet components of a vapors cycle are.
• the returned part of the from the dryer occurring vapor stream, cooled during drying, is in the vapor cycle, before re-entering the drying apparatus, from a gas / gas heat exchanger, that extracts heat from the flue gases, heat fed.
• the recirculated vapor stream leads to such a heating Desiccant drying heat to the drying apparatus.
• the vapor circuit becomes a partial flow, which is the result of the drying apparatus evaporation taking place and possibly as a result of the vapor cycle incoming air is excess, decoupled and as secondary air Firing thus supplied at the local temperatures in the decoupled Burn contaminants and odors contained in the partial flow.
• the gas / gas heat exchanger is usually an air preheater in the Arranged the flow of the flue gas, which this after the Have passed gas / gas heat exchangers for vapor heating, in addition Extracts heat and transfers it to fresh air, which is fed to the dryer.
• an additional heat exchanger is arranged on the heating side flows through the combustion gases entering at the combustion chamber temperature which cool down and the steam on the cooling side generates or a liquid heat transfer medium with a high volume-specific heat capacity warmed up.
• the drying apparatus is divided into one vapor-heated drying section in which the incoming, previously in Gas / gas heat exchangers heated vapors with cooling as a drying agent serve and in a subsequent arranged drying section, in which additional heating of the drying apparatus, at least one Heating register is located, which gives off heat on the heating side as a heating medium Steam condenses or a liquid heat transfer medium of high volume-specific Heat capacity cools, which, in addition to the previous one Heating by the vapors, the drying apparatus, drying heat is fed.
• the additional heat exchanger and that in Drying devices are arranged in a known manner connected to each other and thus form a heating medium circuit.
• the drying apparatus 1 is divided into shown here as a rotating drum, in a first, vapor-heated drying section 2 immediately after the wet feed 3 and in a subsequent one second drying section 4 with additional heating by Heating register 5 within the drying apparatus.
• an additional heat exchanger 8 is arranged in the flow of the combustion gases coming from the combustion chamber 6 is before the gas / gas heat exchanger 7, an additional heat exchanger 8 is arranged. This becomes the heating side of the combustion gases with combustion chamber temperature pressurized, but is against these high heating side Temperatures much less sensitive than the gas / gas heat exchanger because of it is charged on the cooling side with a heat transfer medium which is high has volume-specific heat transfer capacity and therefore causes lower wall temperatures and much lower cooling side Flow cross-sections required than with a gas / gas heat exchanger the case is. This enables the construction of the heat exchanger from steel pipes.
• the additional heat exchanger 8 is used as a steam generator or Thermal oil or pressurized water heater trained, components whose Arrangement immediately behind furnaces has long been more common and proven state of the art.
• this heat exchanger is chosen in this way is that the furnace exhaust gas when it exits the transmitter temperatures from approx. 500 ° C to a maximum of approx. 600 ° C. This ensures that there are no more temperature-related material problems in the gas / gas heat exchanger 7 there and this as a simple and inexpensive sheet steel construction in a long-known and proven design with low Heat storage mass can be executed.
• the furnace temperature can no longer be affected by the thermal load capacity of the gas / gas heat exchanger is limited, optimal be set so that extensive destruction of the pollutants is better guaranteed. Firing temperatures from approx. 900 ° C to approx. 950 ° C are possible.
• the heating medium circuit 9 is for Steam, pressurized water or thermal oil designed, in the drawing the known elements such as. B. pumps, fittings, containers etc. are not shown.
• the heating register arrangement 5 is designed as a capacitor if the additional heat exchanger 8 is a steam generator and is used as a heat exchanger trained if the additional heat exchanger 8 is a heater for Is thermal oil or pressurized water.
• Such heating registers are used as heating elements Indirectly heated dryer within the drying apparatus also generally known and proven for a long time.
• the heating register arrangement 5 causes intermediate heating of the dryer, whereby as is known, the drying speed in this area the pure vapor heating increases, i.e. the required dwell time of the Guts in the drying apparatus sinks, making them smaller can.
• drying with intermediate heating enables compared to single-stage drying, both in the vapor-heated first drying section 2 as well as in the second, additionally heated Range 4 to work with lower temperatures. That increases the Efficiency of the dryer and also reduces the temperature load of the additional heat exchanger and the gas / gas heat exchanger. For Temperature-sensitive goods can be dried more gently.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Drying Of Solid Materials (AREA)
• Air Supply (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=7816029

Family Applications (1)

Country Status (4)

Cited By (5)

Families Citing this family (17)

Citations (1)

Family Cites Families (9)

• 1996
  • 1996-12-23 DE DE19654043A patent/DE19654043C2/de not_active Expired - Fee Related
• 1997
  • 1997-12-12 EP EP97121908A patent/EP0851194A3/fr not_active Withdrawn
  • 1997-12-19 US US08/994,074 patent/US5950322A/en not_active Expired - Fee Related
  • 1997-12-22 CA CA002225569A patent/CA2225569A1/fr not_active Abandoned

Patent Citations (1)

Non-Patent Citations (1)

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