US3721014A - Method of and apparatus for the drying of comminuted material - Google Patents

Method of and apparatus for the drying of comminuted material Download PDF

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US3721014A
US3721014A US00143498A US3721014DA US3721014A US 3721014 A US3721014 A US 3721014A US 00143498 A US00143498 A US 00143498A US 3721014D A US3721014D A US 3721014DA US 3721014 A US3721014 A US 3721014A
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gas
classifier
plant
hot
separators
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P Voelskow
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Siempelkamp Giesserei KG
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Siempelkamp Giesserei KG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat

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  • ABSTRACT 22 l May 14, 1971 A method of and an apparatus for the drying of comminuted material, especially wood particles and fibers [21] App! N04 143,498 and particles and fibers of cellulosicor plant materials in general, as may be used for the production of [30] Foreign Application Priority Data pressed board.
  • the particulate mixture including a fine component, a coarse component and at least one May l9, 1970 Germany ..P 20 24 197.8 further component
  • Such as splinters is subjecxed to gas classification to separate the fines from the coarse [52] US. Cl. ..34/10, 34/57 R, 2259/5153 particles which are conveyed in] respective hot gas [51] Int.
  • the present invention relates to a method of and an apparatus for the drying of comminuted material and, more particularly, to the drying of wood particles (e.g. chips, fibers, dust) or particles of other cellulosic or plant materials, preparatory to the use of such particles in the production of pressed board.
  • wood particles e.g. chips, fibers, dust
  • particulate organic materials especially plant cellulosic material
  • particulate as used herein, and terms of similar import are intended to refer to fibers, granules, chips, dust, splinters and other comminuted forms of cellulosic material, especially wood.
  • a pressed-board plant may include means for subdividing wood into a particulate mixture containing wood dust or powder, wood chips, splinters and fibers, or may subdivide the wood under heat and pressure to provide a mass of cellulosic fiber.
  • Other organic cellulosic sources may also be used.
  • the particulate material is generally deposited in mats or layers, with or without thermally activatable binders, and introduced into a press, e.g. a multiplaten press.
  • a press e.g. a multiplaten press.
  • the proportions of binder and other additives, the pressing temperature and pressure, the ratio of compression and the nature of the particles the resulting board is more or less dense.
  • the board may have high porosity and low structural strength where it is desired for use as an insulating member, or may be of high density, weather-resistance and structural strength where it is used for construction purposes. Between the lowest density stage and the highest density stage, any number of intermediate stages may be provided, simply by varying the above-mentioned parameters.
  • the particulate mixtures used for the production of pressed board generally require drying to a greater or lesser extent for optimum handling and processing characteristics. For example, pressing is facilitated at certain moisture contents, as is milling or further comminution. It is often desirable to deposit the particulate material in several layers; forexample, a core layer of coarse particles flanked by finishing layers of fine particles. In these cases, experiments have shown that optimum handling and pressed-board manufacture require certain moisture contents or even moisture absence in the particles of the several layers.
  • Prior-art systems for drying the particulate materials have hitherto treated them with hot gases in layers on a support of a drying chamber.
  • These directly heated .dryers are provided with combustion chambers in which fuel is burned to produce hot gases which are passed over a bed of the particulate material. When the heating is excessive, the burner is cut off, and residual heat stored in the refractory walls of the combustion chamber is transferred to the gas which, in turn, dries the particles.
  • the nonuniform drying of the particulate material can only be overcome in conventional systems by providing either excessively long-drying times or excessively high temperatures of the exhaust gases leaving the combustion chamber.
  • the treatment duration may reduce the output of the plant and requires high capital expenditure for equipment of a capacity adapted to compensate for long-residence times, and on the other hand the high temperatures waste heat and may cause charring of the product.
  • the invention also has as its object the provision of a method of and a plant for the drying of particulate material to obtain particles of proper moisture content with accurate regulation, for limiting heat loss in the drying process, and for enabling the drying to be carried out at relatively low cost.
  • a fine component and a coarse component of the particulate mixture are separated therefrom by gas classification with hot-gas streams with which the respective particles are dried, the cycles also including gas/particle separators for recovering the fine component and the coarse component from the respective cool-gas streams resulting from the absorption of moisture by the gas stream.
  • a part of each of the coolgas streams or one of the cool-gas streams may be returned to the hot-gas generator while a portion of the remainder is mixed with the hot-gas output which forms the respective hot-gas stream delivered to the cycle.
  • the invention provides that the particulate mixture will be treated with a gas mixture of freshly heated gas (i.e. a mixture of hot gas produced by combustion in the gas generator and recycled cool gas) and cool gas which is recycled by bypasses the hotgas generator.
  • a gas mixture of freshly heated gas i.e. a mixture of hot gas produced by combustion in the gas generator and recycled cool gas
  • the coarse-particle component and the splinter component from which the latter component is separated are afterdried with a gas mixture of the hot gas from the generator and recycled cool gas from the coarse-particle cycle.
  • the fines, recovered in a first gas-operated classifier are afterdried in a drying chamber independent of that for the coarse-particle component with a mixture of recycled cool gas and the hot gas produced in the generator by the combustion of fuel in the presence of a portion of a recycled cool gas as noted earlier.
  • the coarse particles are, in turn, separated from the splinters in a second gas-operated classifier and may be afterdried with the carrier gas which, in turn, is a mixture of the output of the gas generator with recycled cool gas from the separator at which the coarse particles are recovered from the latter gas stream.
  • the present invention provides a drying plant for a particulate mixture including at least the fine component and the coarse component mentioned earlier and, possibly a splinter component as also mentioned.
  • the plant comprises first and second gas-operated classifiers for respectively separating the fine component and coarse component from the mixture; first and second drying chambers connected respectively to the first and second classifiers for treating the particles traversing the respective classifier with respective hot-gas streams; first and second gas/particle separators for separating particles of the components from respective cool-gas streams resulting from the absorption of moisture by the drying gas, the separators being connected in fluid circuit with the first and second chambers as already noted; and generator means for producing a hot gas.
  • respective ducts are provided between each separator and the hot-gas generator to return a portion of the respective cool-gas stream to the generator and incorporate it in the hot-gas stream emerging from the latter.
  • Respective conduits also connect the hot-gas generator with the respective classifiers so that the separation of the fine component from the coarse component is effected by a respective hot-gas stream which also serves as the drying medium for the respective component.
  • Each of the conduits is provided with mixing means for combining another part of one or both of the cool-gas streams of each cycle with the hot gas of the conduit to form the hot-gas stream used to treat the particulate material. Consequently, the proportion of hot gas (generator gas) and cool gas (recycled separator gas) may be adjusted within wide ranges to maintain any desired temperature of the hot-gas stream brought into'contact with the particles.
  • the coarse particles are separated from the splinters in a second gas-classifier operating with a mixture of generator gas and cool gas derived from the coarse particle separator, and the fine and coarse particles are conveyed at least in part in separate hot-gas streams to the latter separators, the recycle portion of the gas only need be reheated.
  • the temperature of the hot-gas stream should be regulated with or in dependence upon the temperature of the waste gases, i.e. the relatively cool-gas streams of the respective cycles and/or the moisture content of the components.
  • the mixing of the relatively cool gas with the generator gas is preferably controlled in accordance with the moisture content of the afterdried fine component and coarse component respectively, the drying cycles being completely independently controllable and regulatable.
  • the temperature of the hot gas is additionally controlled in response to the temperature of gas mixture and/or the temperature of the recycled gas and it has been found preferable to regulate the temperature of the hot gas also in response to the original moisture content of the particle mixture. It is especially convenient to control the threshold of the temperature controller which responds thermostatically to the temperature of the cool-gas stream emerging from the separator in accordance with the mixture contained of the solids emerging from the same separator as will be apparent hereinafter.
  • the mixing stations provided along the conduits connecting the hotgas generator with the respective gas-operated classifiers are preferably formed at the junction of the conduit with a branch leading to the respective gas/particle separator, and with a swingable-flap valve for proportioning the relative amounts of generator gas and recycled cool gas which are fed further along the conduit to the classifier.
  • the position of the flap may be controlled continuously in response to the moisture content of the solids recovered from the respective cycle.
  • a regulating, computing or calculating stage of conventional construction is provided to regulate the operation of the burner of the hot-gas generator and the input thereto include a signal representing the exhaustgas temperature, a signal representing the cool-gas temperature, signals representing the moisture content of the respective components, and a signal representing the moisture content of the particulate material and the input to the plant.
  • the control of the plant can be made highly sensitive by providing both of the moisture detectors responsive to the residual moisture of the product (fine and coarse components) so that they also control the set points of the thermostats of the respective cycles.
  • the controller for the combustion chamber may be of the type described at pages 22 82 ff of PERRY'S CHEMICAL ENGINEERS HANDBOOK, McGraw- Hill Book Company, New York 1963, modified only to provide a servo-mechanism for varying the set point of the thermostat in accordance with the moisture signal.
  • the term signal as used herein can, of course, refer to electrical outputs, but also is intended to refer to any of the outputs or inputs of a system within the meaning of the expression as used in the automatic control art. Consequently, the signal may also be a pressure, where the control system is operated, for example, pneumatically.
  • a signal transmitted to the flap valves of the mixing stations may respond rapidly to close off the cool gas stream and deliver only the generator gas to, for example, the first gas-operated classifier. This will automatically raise the gas temperature at the outlet to cause the thermostant, in turn, to control the combustion by reducing it or terminating it altogether. The system then overresponds.
  • the burner and operation of the combustion chamber are regulated only where both a temperature change of the output gas and increased moisture content indicate that such combustion regulation is required
  • the starting material can be introduced tothe classifiers in succession, prior to any other treatment, and separated into fine-particle and coarse-particle components, each component being subjected separately to drying in a respective chamber.
  • this drying chamber is oversized. This embodiment is based upon the fact that, when an oversized drying chamber is provided, the fine-particle component is substantially completely dried when it reaches the first classifying stage.
  • the mixing stations can be operated independently in response to temperatures detected in the exhaust-gas outlet of the first separator or in the recycling conduit of the second separator.
  • the set points of the flap-type proportioning valves of the mixing stations can be adjusted to establish the desired moisture content of the products and it is also possible to control these plates solely in response to the product-moisture detectors.
  • the final moisture content of the fine-particle component can be set at, say, 8 percent while the moisture content of the coarse particles can be held at 3percent.
  • the setting may be made based upon the type of wood, the character of the particle, the moisture at the input site of the system or other parameters which influence the desired moisture content.
  • the control of the entire drying operation and especially of the burners can be established with thermostatic devices as indicated.
  • a respective drying chamber is provided ahead of each of the classifiers, the duct and separator arrangements being similar to those already set forth.
  • the only disadvantage of arrangements in which the drying chamber is provided ahead of the classifier is that a certain amount of energy is consumed in unnnecessary drying of the splinter component. In general, it is desirable that the splinter component be relatively moist to facilitate milling.
  • the first classifier is provided downstream of the first dryer, there is the advantage that the classifier operates at a constant gas temperature and is not mechanically stressed by excessively high temperatures as may otherwise be present. Constant gas temperatures improve the reproducibility of the classification or separation of fine particles from coarse particles, coarse particles from the splinter component etc.
  • the gas-operated classifier according to the present invention may be of the type described in Chapter 8, page 27 and 50 ff. of PERRYS CHEMICAL ENGINEERS HANDBOOK, McGraw-Hill Book Co., New York, 1963, in which a gas entrains particles of the desired range through a duct away from the classifier chamber.
  • a mill for further comminuting the particles is described at pages'829 ff. and the separators may be of the type described at pages 20-67 ff. of PERRYS CHEMICAL ENGINEERS HANDBOOK.
  • a combustion chamber of the type described at pages 9-30 ff. with appropriate controls may also be used.
  • FIG. 1 of the drawing we show a plant for the drying of particulate matter, especially a fine component 33, a coarse component 34 and a splinter component 35 which are obtained together as a mixture and which is required for use in the production of pressed board.
  • the plant basically comprises a first or fine-particle gas-operated classifier 1 having an inlet fitting lfl for a hot gas stream, an outlet fitting 11 for discharging fine particles entrained by the hot gas stream, a discharge fitting 12 for passing the remainder of the mixture and an inlet 9 into which the particulate material is introduced as a mixture 33-35.
  • a second classifier 2 In series with the first classifier 1, is a second classifier 2, also of the gas-operated type, provided with an inlet fitting 13 connected by a duct 13a with the outlet fitting 12 of the preceding classifier 1 and receiving the mixture of coarse particles and wood splinters therefrom.
  • the gas-operated classifier 2 is also provided with an inlet fitting 14 receiving its hot-gas stream, an outlet fitting 15 adapted to carry off the coarse-particle fraction received in the classifier 2 in the hot-gas stream, and a further fitting 16 for discharging the splinter component.
  • the first gas-operated classifier 1 forms a first fluid cycle with an afterdrying chamber 3 which has its inlet fitting 30 connected to the outlet fitting 11 and classifier 1 via duct 17.
  • the chamber 13 is dimensioned to permit the desired duration of contact with the fine particles and the entraining hot gas and thus to dry the particles.
  • the chamber 3 has a discharge fitting 19 from which the particle-gas mixture is delivered to a separator 4 of the type previously described.
  • the inlet 4a of this separator is connected to outlet 19.
  • the separator 4 is designed to separate the fine particles recovered by classifier 1 from the particulate mixture, from the gas entraining this component into the separator.
  • the separator has an outlet 24 for the dried fineparticle fraction, an outlet 21 in the form of a duct connecting the separator with a hot-gas generator 7, and a vent or chimney 23 adapted to release a part of the cold gases to the atmosphere.
  • an afterdrying chamber 5 also dimensioned to provide the desired degree of contact between the hot gas stream and the coarse particles entrained therewith from the gas-operated classifier 2.
  • the chamber is provided with an inlet 5a connected via duct 18 to the outlet fitting of the classifier 2.
  • the discharge port of chamber 5 is connected to the inlet 6a of a gasparticle separator 6 (see the cited portions of PERRYS CHEMICAL ENGINEERS HANDBOOK) which separates the relatively cool gas from the coarse particles.
  • the latter is discharged at 25.
  • the separator 6 also includes, as part of the coarse-particle cycle, a duct 22 which delivers a portion of cool gas, freed from particles, to the combustion chamber 7.
  • separator 4 At the discharge side 24 of separator 4, there is provided a comminutor or mill 8, as described in the cited pages of PERRYS CHEMICAL ENGINEERS HANDBOOK, for further subdivision of the fine component.
  • the combustion chamber 7 is provided, in addition to inlets 21 and 22 for respective portions of the cold gas resulting from moisture pickup in the drying chamber, with a burner B controlled by a computer type regulator 36 of conventional construction, the function of which will become more readily apparent hereinafter.
  • a hot gas duct 26 extends from the combustion chamber 7 and is branched at 26a and 26b to form a pair of hot-gas conduits which are connected to the respective classifiers 1 and 2 via conduits 30 and 31, respectively. Between the conduits 30 and 26a and the conduits 31 and 26b, respectively, there are provided mixing stations 27 and 28 with swingable-flap valves 32 which control the temperature of the gas delivered to the respective classifiers.
  • Each of the mixing devices receives a portion of relatively cool gas delivered via duct 29 from the separator 6, via branches 29a and 29b, for mixture with the generator gas to regulate the temperature of the hot gas stream traversing the conduits 30 and 31 and entering the classifiers l and 2, respectively.
  • the apparatus also includes a control system having a moisture detector 39 of conventional construction for determining the moisture content of the particulate mixture introduced to the inlet 9.
  • Moisture sensors 40 and 41 for detecting moisture content of the discharged particles at the outlet mill 8 and the outlet 25 of separator 6, respectively, and thermostatic devices 37 and 38 responsive to the temperature of the cool gas traversing duct 23, and the cool gas traversing duct 22, respectively.
  • the flaps 32 are connected with the product sensors and the outputs of the latter may also be used to control the set point of thermostatic devices 37 and 31, respectively.
  • the thermostats of the raw-mixture sensor deliver the signals to the controller 36.
  • the set points of the valve flaps 32 are established in accordance with the desired moisture content of the respective product, namely, the first or fine component and the second or coarse component of the particle mixture.
  • the particle mixture is introduced into the inlet 9 through the classifier 1 in which the fine-particle fraction is entrained by the hotgas stream from line 30 through the duct 17 and into the afterdrying chamber 3. Drying of the fine particles occupies the entire duration of contact of the particles with the hot-gas stream and eventually cools the latter as the gas-entrained particles enter the separator 4.
  • the cool-gas stream is vented at 23 in an amount equal to the gas product rate in the combustion chamber 7.
  • the fine-particle fraction passes at 24 into the mill 8 in which it is further subdivided to the size range suitable for use as cover layers in the manufacture of pressed board.
  • the non-vented portion of the cool gas is returned to the combustion chamber 7 and serves in part to reform the hot gas or as a heatable gas component which is entrained with the generator gases.
  • the sensor 40 detects the moisture content and substantially instantaneously adjusts the flap 32 of the mixing means 27 to reduce the cool gas flow from branch 29a and thereby increase the proportion of hot generator gas supplied to the classifier 1.
  • the heat output may be reduced with respect to another input, in which case the temperature of the gases introduced into classifier 1 will be reduced accordingly.
  • flap 32 of the mixing means 27 will be adjusted accordingly to throttle the flow of cool gas from branch 29a into the classifier l which will increase the gas temperature in the latter. Since the duration of contact of the entire particle mixture with the hot gas in the first classifier is minimal, both the coarse-particle fraction and the splinter component pass substantially heated into the second classifier 2.
  • the coarseparticle fraction is entrained with a hot gas strain supplied at 31 into a duct 18 and thence into the drying chamber which provides the requisite duration of contact to reduce the moisture content of the coarse-particle fraction to a level consistent with its use as the intermediate layer in the manufacture of pressed board.
  • the dried particles are separated at 6 into the product 34 and into the cool gas stream, a portion of which is recycled at 22 to the heating chamber 7. It has already been pointed out that the portion of the cool moist gas recycled to chamber 7 is heated by combustion of a fuel which results in the production of additional hot gas of low moisture content.
  • the gas mixture (hot gas stream) is thus never saturated with moisture, and the moisture lost by the system leaves with the gases vented at 23.
  • the recycled cool gas may also be in part reacted with the fuel as an oxidizing constituent because of the presence of water vapor. It will be appreciated that the flaps 32 consequently not only affect the temperature, but also the moisture content of the hot-gas stream used in the classifiers.
  • the latter mixing unit has a flap valve 32 controlled with a set point determined by the desired moisture content of the product.
  • the sensor 41 detects this moisture content and adjusts the flap 32 accordingly, i.e. to increase the temperature of the gas entering the classifier 2 when the moisture content exceeds the set point value and to decrease the temperature when the moisture content falls below a predetermined value.
  • the thermostat 38 calls for an adjustment of the controller 36 to reduce the output of the burner whereas the output of the latter is raised when the thermostat 38 indicates insufficient temperature of the gas traversing the coarseparticle path.
  • the splinter component, recovered at 35 passes the classifier 2 substantially without drying and hence, is relatively moist, a convenience for aftermilling or grinding.
  • the most significant advantage of the aforedescribed system is that control of the moisture content is independent of the operating conditions of the burner in the sense that control is possible without turning the burner off and on merely to adjust the temperature of the gases delivered to the respective drying arrangements. Furthermore, the drying cycles are substantially independent and only a small proportion of the heat of the system is lost by the venting of the moisture-laden air to the atmosphere at 23.
  • the apparatus can be operated with high temperatures in the heating chamber 7 since the hot gases are mixed with cool gases prior to introduction into the classifier and thus the combustion essentially can be improved with increasing heat loss.
  • the classifiers 1 and 2 are disposed downstream of the dryer 3 which is provided with the inlet 30 for the hot-gas stream used to operate the classifier 1.
  • the particle mixture 33, 34, 35 is introduced at the inlet 9 into the over-dimensioned heating chamber 3 in which the fine-particle fraction is substantially completely dried while the coarse-particle fraction is only slightly dried.
  • the mixture passes at 19 into the classifier 1 in which the fineparticle fraction is diverted in the gas stream through duct 11 to the separator 4 in which the fine-particle fraction is recovered.
  • the fine fraction is milled at 8; after separation of the fines in classifier 1, the coarse particles are separated in classifier 2 and delivered to the drying chamber 5 as described in connection with FIG. I.
  • the splinter component 35 passes through the drying chamber 3 but not through the drying chamber 5.
  • the system of FIG. 2 is provided with controls analogous to those of FIG. 1.
  • the coarse-particle fraction and the splinter component pass into the dryer 5 instead of the classifier 2 and only enters the latter after traversing the dryer 5. Otherwise, the system is equivalent to that of FIG.-2.
  • the system of FIG. 3 can, of course, be modified in that the inlet 9 can be provided directly in the hot-gas line 30.
  • the separator 4 can be connected to the mixing stations in all of the embodiments described and the vent 23 eliminated if other means are provided to prevent the build-up of gas.
  • all of the cool. gas of separator 6 may be supplied to the generator 7.
  • a drying plant for a particulate mixture including at least a fine component and a coarse component said plant comprising in combination:
  • first'and second gas-operated classifiers for respectively separating said fine component and said coarse component from said mixture
  • first and second drying chambers connected respectively to said first and second classifiers for treating particles traversing the respective classifiers with respective hot-gas streams;
  • first and second gas/particle separators respectively connected in fluid circuits with said first classifier and chamber and with said. second classifier and chamber for separating particles of said components from respective relatively cool gas streams formed in a respective chamber upon drying of particles therein;
  • each of said mixing means includes a branch duct connected to the respective conduit at a junction therewith and communicating with said one of said separators, and swingable-flap means at the respective junction for controlling the proportions of the hot gas derived from said generator means and the cool gas stream derived from said one of said separators which form the respective hotgas stream supplied to the respective classifier.
  • thermostat means each has a set point, further comprising means for adjusting said set points in accordance with the moisture contents of said components as determined by said moisturedetection means.

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  • Drying Of Solid Materials (AREA)
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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4130945A (en) * 1976-09-06 1978-12-26 Klockner-Humboldt-Deutz Aktiengesellschaft Method for the production of fine-grained mixture of mineral solids
US4627173A (en) * 1983-04-11 1986-12-09 The Garrett Corporation Fluid bed hog fuel dryer
US4628833A (en) * 1983-04-11 1986-12-16 The Garrett Corporation Fluid bed hog fuel dryer
US6639671B1 (en) * 2002-03-01 2003-10-28 Msp Corporation Wide-range particle counter
US20060075682A1 (en) * 2004-10-12 2006-04-13 Great River Energy Method of enhancing the quality of high-moisture materials using system heat sources
US20060107587A1 (en) * 2004-10-12 2006-05-25 Bullinger Charles W Apparatus for heat treatment of particulate materials
US20060112588A1 (en) * 2004-10-12 2006-06-01 Ness Mark A Control system for particulate material drying apparatus and process
US20070193926A1 (en) * 2004-10-12 2007-08-23 Ness Mark A Apparatus and method of separating and concentrating organic and/or non-organic material
US20090056162A1 (en) * 2007-08-28 2009-03-05 Mcmahon Jr Robert James Apparatus and method for reducing a moisture content of an agricultural product
US8062410B2 (en) 2004-10-12 2011-11-22 Great River Energy Apparatus and method of enhancing the quality of high-moisture materials and separating and concentrating organic and/or non-organic material contained therein
US20110305897A1 (en) * 2009-03-10 2011-12-15 Kronotec Ag Wood chip drying system for drying wood chip and associated method for drying wood chip
US10124399B2 (en) * 2015-03-23 2018-11-13 Maschinenfabrik Gustav Eirich Gmbh & Co. Kg Molding sand cooler
US11215360B2 (en) * 2015-08-18 2022-01-04 Glock Ökoenergie Gmbh Method and device for drying wood chips

Citations (4)

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US1669012A (en) * 1925-12-04 1928-05-08 Nordstrom Otto Drier
US2956347A (en) * 1957-07-23 1960-10-18 Combustion Eng Drying method and apparatus
US3256614A (en) * 1961-05-29 1966-06-21 D & S Engineering Ltd Plant for drying of finely divided material, especially wood pulp and cellulose
US3447678A (en) * 1967-04-20 1969-06-03 Donald L Henry Method for separating expanded perlite with minimum particle breakage

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1669012A (en) * 1925-12-04 1928-05-08 Nordstrom Otto Drier
US2956347A (en) * 1957-07-23 1960-10-18 Combustion Eng Drying method and apparatus
US3256614A (en) * 1961-05-29 1966-06-21 D & S Engineering Ltd Plant for drying of finely divided material, especially wood pulp and cellulose
US3447678A (en) * 1967-04-20 1969-06-03 Donald L Henry Method for separating expanded perlite with minimum particle breakage

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4130945A (en) * 1976-09-06 1978-12-26 Klockner-Humboldt-Deutz Aktiengesellschaft Method for the production of fine-grained mixture of mineral solids
US4627173A (en) * 1983-04-11 1986-12-09 The Garrett Corporation Fluid bed hog fuel dryer
US4628833A (en) * 1983-04-11 1986-12-16 The Garrett Corporation Fluid bed hog fuel dryer
US6639671B1 (en) * 2002-03-01 2003-10-28 Msp Corporation Wide-range particle counter
US20060112588A1 (en) * 2004-10-12 2006-06-01 Ness Mark A Control system for particulate material drying apparatus and process
US20060107587A1 (en) * 2004-10-12 2006-05-25 Bullinger Charles W Apparatus for heat treatment of particulate materials
US8523963B2 (en) 2004-10-12 2013-09-03 Great River Energy Apparatus for heat treatment of particulate materials
US20070193926A1 (en) * 2004-10-12 2007-08-23 Ness Mark A Apparatus and method of separating and concentrating organic and/or non-organic material
US20060075682A1 (en) * 2004-10-12 2006-04-13 Great River Energy Method of enhancing the quality of high-moisture materials using system heat sources
US8651282B2 (en) 2004-10-12 2014-02-18 Great River Energy Apparatus and method of separating and concentrating organic and/or non-organic material
US7987613B2 (en) * 2004-10-12 2011-08-02 Great River Energy Control system for particulate material drying apparatus and process
US8062410B2 (en) 2004-10-12 2011-11-22 Great River Energy Apparatus and method of enhancing the quality of high-moisture materials and separating and concentrating organic and/or non-organic material contained therein
US8579999B2 (en) 2004-10-12 2013-11-12 Great River Energy Method of enhancing the quality of high-moisture materials using system heat sources
US20090056162A1 (en) * 2007-08-28 2009-03-05 Mcmahon Jr Robert James Apparatus and method for reducing a moisture content of an agricultural product
US7856737B2 (en) * 2007-08-28 2010-12-28 Mathews Company Apparatus and method for reducing a moisture content of an agricultural product
US20110305897A1 (en) * 2009-03-10 2011-12-15 Kronotec Ag Wood chip drying system for drying wood chip and associated method for drying wood chip
US8832959B2 (en) * 2009-03-10 2014-09-16 Kronotec Ag Wood chip drying system for drying wood chip and associated method for drying wood chip
US10124399B2 (en) * 2015-03-23 2018-11-13 Maschinenfabrik Gustav Eirich Gmbh & Co. Kg Molding sand cooler
US11215360B2 (en) * 2015-08-18 2022-01-04 Glock Ökoenergie Gmbh Method and device for drying wood chips

Also Published As

Publication number Publication date
FR2091800A5 (fr) 1972-01-14
CA919619A (en) 1973-01-23
DE2024197A1 (de) 1971-12-02

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