A CONTINUOUS DRYING AND/OR HEATING PROCESS AND APPARATUS

Abstract: Apparatus and process for drying and/or heating materials. This invention was designed for use in the production of charcoal from wood feed material; however, it can be used to heat and/or dry many types of materials. Feed material is disposed in a reactor (11) wherein uncondensed pyrolysis volatiles generated by heating or drying are continuously recirculated in direct contact with feed material and withdrawn to a heat exchanger (76) where the pyrolysis volatiles are heated to a temperature within a temperature range which prevents condensation of the volatiles and acts to maintain the pyrolysis reaction of the feed material.

Description: CONTINUOUS DRYING AND/OR HEATING PROCESS AND APPARATUS SUMMARY OF THE INVENTION This invention was primarily designed for the continuous pro¬ duction of charcoal from wood feed material. However, the invention has been found to be useful in many other areas. While its primary use is still as a charcoal producing appar- atus, it can also be used in grain drying, bulk powder storag various calcining processes, such as CaC0 3 →- CaO and in many other instances. The apparatus can be used any time it is de¬ sired to dry or heat feed material such as powders, grains or chips. As the invention was primarily designed to produce charcoal, its use as a charcoal producer will be described in detail. The basic problem of charring wood chips, or sawdust, or any wood feed to produce charcoal, is to uniformly heat a signi- ficant mass of the feed material in an oxygen deficient atmos¬ phere while efficiently collecting and managing the evolved gases. The present invention allows for the hot gases heating the charcoal producing feed material, to be uniformly circu¬ lated therethrough, and to be uniformly collected along with the gases and vapors produced by the charcoal producing reac¬ tion. In accordance with this invention, feed material is made into charcoal in a short time, using little energy. Th.e present invention also provides for efficient control and col¬ lection of the g-ases, preventing them from escaping into the atmosphere, thereby eliminating pollution. An advantage of this invention is that some of the released and collected gases and vapors are burned to provide energy to be used in the process ? thus, the external energy needed for the process is reduced. Further, some of the collected hot gases are cir culated in the charcoal producing process, thereby preserving energy. The invention comprises a process and apparatus for the heat¬ ing and drying of materials in powder, chip, or grain form. O /iPl For convenience an apparatus embodying the invention as u as a charcoal producer is described below. However, this bodiment is but one way to carry out the inventive proces is but one embodiment of the inventive apparatus. The ap atus comprises means for circulating hot gases through wo feed material in a reactor which provides an oxygen defic atmosphere; wherein said means include an array of input nels extending through the feed material, through which h gases introduced into the feed material, and an interleav ray of output channels extending through the. feed materia lect, manage, and discharge said hot gases and any gases vapors released by the charcoal producing reaction. It is an object of this invention to provide an apparatus process for the heating and/or drying of materials such a ders, grains, or chips. It is also an object of this invention to provide an appa capable of using wood waste in the form of chips or sawdu without size sorting and to produce charcoal from them. It is also an object of this invention to provide a charco producing apparatus small enough to be contained on a fla bed trailer for convenient portability. It is also an object of this invention to .provide an appa for the production of charcoal whic is amenable to simpl automation for minimal operator attention and th.e reactor which has no moving parts. It is also an object of this invention to collect condensi vapors from a charcoal producing reaction without the nee tight mechanical seals, and to burn the generated non-con bile gases to return heat into the reaction, while elimina atmospheric pollution and reducing external energy require It is also an object of this invention to use heat from t • charring process to dry th.e chips or sawdust feed material prior to their insertion into the charring process or apparatu How the foregoing and other objects are achieved are described in the detailed description below and in the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of the apparatus; Fig. 2 is a partial vertical sectional view of the apparatus of Fig. 1; Fig. 3 is a sectional view taken along lines 3-3 of Fig. 2; Fig. 4 is a fragmentary vertical sectional view of the filled reactor of apparatus of Fig. 1; Fig. 5 is a perspective view of a reactor module; " Fig. 6 is a side view of the conveyor of the apparatus of Fig. 1; Fig. 7 is a sectional view of the conveyor taken along line 7-7 of Fig. 6; Fig. 8 is a sectional view of the conveyor taken along lines 8-8 of Fig. 6; Fig. 9 is a side view of another reactor unit embodying inven- tion; Fig. 10 is a partial sectional view of the reactor of Fig. 9 taken along lines 10-10 of Fig. 9; Fig. 11 is a partial sectional view of the reactor of Fig. 9 taken along line 11-11 of Fig. 9; and Fig. 12 is a persepctive view of a wall of the reactor of Fig. The present invention was originally designed as a charco producer. While numerous oth.er uses have been found for its primary purpose is still as a charcoal producer;- thu the detailed description will describe the apparatus in i charcoal producing function. No limitations as to the us of the apparatus or process are intended. In addition, w the description is of the apparatus, the inventive proces is embodied in that apparatus and the invention is not l ited to an apparatus. Charcoal is produced by heating wood feed material in oxy deficient atmosphere.. In the apparatus and process for c tinuous production of charcoal there are essentially two tems involved; first, the movement. of the hot gases, and second, the movement of the wood feed material into and o of the apparatus. The movement of the hot gas is shown schematically in t apparatus of Fig. 1. Fuel gas enters heating system 14 through valve 32 and is burned by upper burner 33 of the of burners 33 and 35. Its fumes rise and exit through ch ney 47. Fan 19 blows air around cylinder 76 of heating un 14 where it is heated by the burning fuel gas and kept fr mixing with the fuel gas or its fumes. In this embodimen as it is convenient, air is used as the heat carrier; how there are no limits as to the. type of gas to be h.eated an used as the carrier of heat, other than those imposed by charring process itself. However, wh.en air, meaning 0 2 a 2 , is used only at start up of th.e apparatus, as the oxy is consumed the feed material 12 is heated up to reaction temperature. Thereafter, gases are recirculated and any cess gas is introduced to burner 35 described below. Tile recirculating gas exits cylinder 76 through, valve 15 and, during the producing stage of the apparatus, goes upwards through pipe 41, through input pipes 22, 23, 24, and 25, into charcoal reactor unit 11. Dampers 74 adjust the flo through pipes 22-25 and manometers 73 measure the pressur at different levels within unit 11. As will be shown, it OMPI desired that the pressure at the top and bottom of reactor unit 11 be at atmospheric pressure to prevent escape of pol¬ luting gases and dampers 74 and valve 75 are adjusted to achei this. The hot gases then circulate through the feed material 12 in reactor unit 11, as will be described below in greater detail. The hot gases and any gases produced by the charring process are collected and exit reactor unit 11 through output pipes 26, 27, 28, 29 and 30. From there it goes through escape pipe 46, through valve 31 and pipe 72, and into chamber 37 which is positioned along a length of conveyor 13. In chamber 37 condensible vapors, in tfie hot gases supplied thereto, con¬ dense and move into liquid traps 16, 17 and 18. The hot gases then exit chamber 37 through pipe 38, and go down chimney 47 via pipe 20 where they are preheated by the fumes rising off burner 33. The hot recycled gases go through valve 34, into fan 19, and then, in part, go through valve 75 to be burned in burner 35 and, in part, go through cylinder 76 to be reheated and recycled. While the hot gas is being recirculated, feed material 12 moves as follows. It is first placed on conveyor 13 and is carried up conveyor 13 by screw auger 36 while being heated and dried by the hot gas in chamber 37. The feed material 12 is then dropped through connection 39 into the top 49 of re¬ actor unit 11. Feed material 12 at the top 49 of reactor unit 11, slowly makes its way down through reactor while being heated by the hot gas and made into charcoal. The charcoal is then removed from the bottom 50 of the reactor unit 11 by removal auger 48. Feed material 12 moves down the reactor unit 11 due to the removal of charcoal by removal auger 48 and due to th.e contin- uous shrinkage of the feed material 12 during th.e charring process. Therefore, the speed of conveyor 13, of fan 19, and of removal auger 48 are set such, that feed material 12 is converted into charcoal by the time it reaches the bottom 50. This permits the process and apparatus to be continuoj -^QB-EA If new feed material is constantly being added at the top 49 reactor unit 11, while charcoal is constantly removed fro bottom 50 of reactor unit 11. Downward movement of the f material 12 through the reactor unit 11 is assisted by th vibration imparted to reactor unit 11 by fan 19 , load aug 36 , unload auger 48, and the machines driving them. Shou plugging or clogging of the reactor 11 ever be a problem, lodged material could be loosened by auxiliary mechanical jarring of the reactor unit 11. If such lodging becomes quent, intermittent jarring is easily mechanized. Reactor unit 11 has a wall 45 on its one side, and oppose t-ernatingly stacked input 51 and output 40 reactor module Fig. 5 shows a typical output module 40. Output pipe 26 connected to output module 40 which has angled members 44 connected to its core 42 at holes 43. The only differenc between an input module 51 and an output module 40 is the number and position of the holes 43 of the angled members and 52. An input module 51 h.as five holes 43 and three f * angled members 44 and two half angled members 52, whereas an output module has four holes 43 and four full angled m bers 44. CSee Fig. 3}.. Fig. 3 shows a more detailed picture of the alignment of " ule≥s 40 and 51 and of their respective holes 43 and angle members 44 and 52. Feed pipe 41 is shown connected to in pipes 22-25 which, are, in turn, connected to input module Escape pipe 46 is connected to output pipes 26-30 which a in turn connected to output modules 40. The holes 43 of put reactor module 51 and output reactor module 40 are of as shown. The ratio of holes 43 and their relative align is a mere preferred embodiment of the invention and is no required. Fig. 4. shows the flow of gases. A portion of reactor un 11 is shown filled with, feed material 12. Diamond shaped channels 53 are created in feed material 12, as it is def by angled pieces 44 and 52 (52 not shown in Fig.4) while downward through reactor unit 11. Hot gases flow from feed pipe 41, through input pipe 22, into core 42 on through the five holes 43, and into channels 53 created by angled members 44 and 52. ' The hot gases then circulate through feed material 12 and are collected by and exit through channels 53 created by angled members 44 of- the output modules 40. These channels 53 provide large surface areas for the hot gases to uniformly penetrate the feed material 12. In addition the gases have short distances to travel preventing condensation of the gas vapors in cool areas of the feed material 12. Channels 53 extend through feed material 12 and are created by angled members 44 and 52 which push feed material 12 aside as it moves downward. Any other means for producing such chan nels 53 is equally within the scope of this invention. Not only angled members 44 will create channels 53 within the scop of the invention, but also flat members, flat members with slightly curved edges, inverted U-shaped members, or even cyl¬ indrical members with apertures at their bottom. In this em- bodiment, the means for creating a channel also break up and stir the feed around as it moves downward. Channels 53 allow the introduction of the hot gases throughout their entire length, which is substantially the entire width of reactor unit 11. Thus, feed material 12 along the entire width of reactor unit 11 is uniformly heated by the hot gases. Without these channels 53, the hot gas would enter the reactor unit 11 at a point or series of points and char the feed mat¬ erial 12 immediately surrounding the point or points. The hot gases would then go straight to an exit and only the feed mat¬ erial 12 along that path would get heated and char. If it charred at all, the other feed material 12 would only char after a long time, as little heat would reach it. A large waste of energy would be created as, after being made into charcoal, feed material 12 near the input channel would be heated until the heat reached feed material 12 far from the input channels. In addition, a poor quality charcoal would be produced as the feed material 12 would not be uniformly charred. In this, the preferred embodiment, there is a uniform arr of channels 53 across substantially the entire length of 11 (as can be seen in Fig. 2) . In addition to creating a proper circulation of hot gases these channels cause the 5 ular break up of feed material 12 moving down reactor uni 11 and allow different portions of feed material 12 to be direct contact with the hot gases. The channels 53 also hibit packing or densification of material 12 in the reac Any local settling merely alters the bottom V-angle of ch 10 53 without significantly compacting material 12. At no d in the reactor does the feed material 12 "feel" the entir load of the column of material about it, rather, the arra angled members 44 and 52 share some of the load. Further more of the individual angled- members 44 and 52 bear a he 15 load. The array of output channels 53 similarly allows f the uniform collection of both the hot gas. and any gases vapors produced by the charring process; thus, preventing from merely escaping into the atmosphere and polluting it Some of these gases can be burned, to provide energy, be u 20. again in the charring process, or be used to dry the feed erial. Fig. 6 shows feed material 12 being pushed up conveyor 13 screw auger 36 which is driven by a motor (unseen) . Fig. 25 shows a cross section of conveyor 13 at a point which doe not contain chamber 37. U-shaped trough 55 with, its mold 56 is shown containing screw auger 36. Fig. 8 shows a cr sectional view of conveyor 13 at a point containing chamb 37. U-shaped trough 55 and U-shaped container 57 have tϊi 30 upper parts welded together at point 58. Between U-shape trough 55 and U-shaped container 57 is chamber 37. Referring back to Fig. 1 the start-up of the operation wi be described from the time at wϋich. reactor unit 11 is un 35 filled. To start the process, the liquid traps 16, 17 an are filled to prevent the loss of hot air to the atmosphe Burner 33 is then lit and set for maximum output, and fan is started with its speed adjusted to keep output tempera O PI WIPO at a desired level. Air is heated in cylinder 76 of heater 14 and is pushed up through valve 15 which has been adjusted to divert the hot air into pipe 71 through chamber 37 of con¬ veyor 13, out pipe 38, down chinmey 47, through pipe 20, and into heater 14 where it is reheated and recycled. Feed material 12 is then added to conveyor auger 36 whose speed is set to ensure that the feed material 12 is dry when it reaches the top of conveyor 13. When reactor unit 11 is filled with feed material 12, valve 15 is switched to direct hot air into reactor module 11. The speed of fan 19 is ad¬ justed so that the air exits heat exchange cylinder 76 at temperatures typically ranging from 750° to 1000°F. In order to preheat the feed material at the bottom of reactor unit 11, the dampers 74 are adjusted to allow hot air to enter the reac tor unit 11 only through input, pipes 24 and 25. The feed mat¬ erial 12 initially at the bottom of unit 11 has less of a dis¬ tance to move; thus it will be heated for a much shorter time. Therefore, to ensure that it is fully charred when removed, ' it must be preheated. As the feed material 12 is heated, the first evidence of a charring reaction is the evolution of vapors which condense in liquid traps 16, 17 and 18. This causes a build up of gas pressure in the system which is reflected in U tube manometers 73. Dampers 74 are then adjusted to let the hot gas go through all input pipes 22-25. The dampers 74 and valve 75 are further adjusted to keep the pressures at top manometer 73 and bottom manometer 73 just at atmospheric pressure. Pressures at manometer 73 on input modules will, of course, be above atmospheric pressure while pressures within output modules will be below atmospheric pressure. As the reaction proceeds, a flame will develop in lower burner 35, burning the combustible gases which have returned through valve 75. During the start-up of the reaction, the accumulating gases being released from the recirculating " closed" circuit through valve 75 will not be combustible as they sill consist of mostly water vapor, CO.,, 0 2 and only dilute amount of com bustibles (CO, H 2 , CH- , etc.) which will be consumed in t overhead gas flame of burner 33. However, as the reactio proceeds, the gases through valve 75 become more combusti and a flame develops in lower burner 35. The completion of the charring reaction in reactor unit 1 evidenced by a reduced gas flow through valve 75. When t condition is achieved, the removal auger 48 is started, n feed material 12 is loaded onto auger 36, and the machine erates as described above. During the steady state op ation burners 33 and 35 are set to maintain a constant o temperature. The speed of feed auger 36 is set to add fe material 12 to reactor unit 11 at a rate commensurate wit r-emoval rate of removal auger 48. While the apparatus can be continuously used to produce c coal, it can also be stopped. To stop the operation no n feed material is loaded onto auger 36 and removal auger 4 • is stopped. Valve 31 is set so that all gases which exit reactor unit 11 through escape pipe 46 go through valve 3 down valve 34, through fan 19, and up through valve 69 to burner 70, where they are burned off without producing ne hot gas in the apparatus. During this operation valve 32 and 75 are closed so that recirculating gas is not reheat Valve 69 is adjusted to relieve any pressure build up of Fig. 9 shows another embodiment of the reactor module uni the charcoal producing apparatus. In this embodiment the heated gases enter the reactor unit through feed pipe 59 ing the place of pipe 411 , go into the chamber 81 of the actor, through holes 63 in wall 66, and into the chambers created by inlet angled pieces 62. From there the air ci lates through, the feed material 12, goes into chambers 53 created by the outlet angled pieces 61, through hole 64 o outlet wall 67, into the chamber 82 and out through outle pipe 60 (which takes the place of pipe 46) . As was discu above, the pressures in the upper and lower parts of the QMPI WIPO actor unit must be controllable; thus, baffles 79 and 80 are located in chamber 82 and can be independently opened or closed as they revolve on hinges 77 and 78. Thus, when the baffles 79 and 80 are in the horizontal positions, the pres- stores in the top and bottom areas of the reactor unit are al¬ lowed to build. As the baffles 79 and 80 rotate on hinges 77 and 78 into vertical positions, the gases are allowed to es¬ cape through outlet pipe 60 relieving the build up of pressure Fig. 10 shows the inlet wall 66 with holes 63 inlet angled pieces 62 and outlet angled pieces 61. Fig. 11 shows outlet wall 67 with outlet holes 64 outlet angled pieces 64 and inlet angled pieces 62. As can be seen, the angled pieces in this embodiment range the whole width of the reactor unit, and are attached to the walls 66 and 67. In this embodiment, there are triangular pieces 65 and U-shaped pieces 83 (shown better in Fig. 12) upon which the angled pieces 62 hang and into which the half-angled pieces 84 are placed. While the embodi¬ ment of Fig. 9 is obviously more suited for this method of • attaching the angled pieces, it is clear that in the first em¬ bodiment discussed this method could also be used. The present invention, with, its array of input channels ex¬ tending through the feed material, allows for uniform charring ■ • • of the feed material. The hot gases are introduced through the channels, and uniformly reach and heat the feed material to make uniform quality ch-arcoal. Without these channels, the feed material closest to the entering hot gases would be charred first. In the present invention, no energy is wasted heating feed material that has already charred to allow hot gases to slowly make their way to feed material far from the entrance. The time necessary to char, and the energy required to char are, thereby, held to a minimum. The array of output channels which extend through the feed material to collect the hot gases, and through which the hot gases exit, allow for an efficient collection and management of the gases. That is, both the hot air and the gases and vapors produced by the charring reaction itself, are effi ently collected and managed instead of merely Being allow to escape into the atmosphere to pollute. This efficient collection of gases has many benefits, as the collected g can be used in the condensor conveyor to dry and heat the material before it enters the reactor module,, or can be u again in the charring reaction after being heated. This benefit as these gases are already hot, and a minimum of gy is needed to bring their temperature up to that requir by the charring reaction. In addition, any combustible g (Including those created by the charring), w ic 'are effi ly collected, can be used in the lower burner 35, as desc Thus, the amount of fuel gas necessary to continue the ch reaction is reduced, or eliminated entirely after start u While the present invention h.as been described as an appa for the production of charcoal, it has many other uses. those uses are .grain drying, bulk powder storage and vari calcining processes such, as CaCO- • * ■ CaO. As can be seen the detailed description above, the present invention wou useful in those other applications. The present inventio circulates hot gases through a mass of feed material and lects those gases efficiently. While.some types of feed erial undergo a reaction (wood feed material and CaCO,} o types of feed material do not (grains and some powdersl. apparatus or process is in no way dependent upon the feed erial undergoing a reaction. The invention merely suppli the hot gases efficiently and efficiently collects them. present invention is excellent, for the drying of any type material as the channels through the feed material regula break up the feed material as it moves through the reacto This regular breakup prevents the clumping of material, a lows different surface areas of the feed material to be e to the hot gases. In addition, it allows the hot gases t properly and efficiently circulate uniformly throughout t tire mass of feed material. While the invention has been particularly shown- and descr -13- with reference to a preferred embodiment of the apparatus and process thereof , it will be understood by those skilled in the art that various ~ changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims: WHAT IS CLAIMED IS: 1. A process for heating and charring wood chips, wood w sawdust and the like in order to produce charcoal or char material therefrom which, comprises passing said wood chip wood waste, sawdust and the like through a heating and ch ring zone, contacting said wood chips, wood waste, sawdus and the like within said heating and charring zone with h gases in order to generate therefrom combustible gas and produce charcoal or char material, said hot gases being a suitable temperature, withdrawing said charcoal or char m 0 erial from said heating and charring zone, separately wit drawing said hot gases and said generated combustible gas heating said withdrawn hot gases and combustible gas to s suitable temperature, introducing said heated hot gases a combustible gas into said heating and charring zone in co 5 with additional wood chips, wood waste, sawdust and the l to generate therefrom additional combustible gas and addi al charcoal or char material, from time to time combustin ' portion of said generated combustible gas to produce hot bustion gases, and employing heat derived from said hot c 0 bustion gases for said heating of withdrawn hot gases and bustible gas prior to re-introducing said hot gases and c bustible gas into said heating and charring zone. 2. The process of Claim 1 wherein said wood chips, wood 5 sawdust and the like are preheated or dried prior to bein passed through said heating and charring zone. 3. The process of Claim 2 wherein said preheating or dry is accomplished employing heat derived from said hot comb 0 tion gases produced by combusting said generated combusti gas. 4. The process of Claim 1 wherein said suitable temperat ,. is a temperature in the range 450° to 1000°F. OMPI /,. YvIFO 5. The process of Claim 1 wherein said heated hot gases and combustible gas introduced into said heating and charring zone are oxygen deficient. 6. A process for producing charcoal or char material from cellulosic material, such as wood chips, wood waste,, sawdust and the like, which comprises passing said cellulosic mater¬ ial through said heating and cϋarring zone, contacting said cellulosic material therein with hot gases to char said cell- 0 ulosic material and to generate therefrom a combustible gas, withdrawing said char material and gases including the afore¬ mentioned combustible gas from said heating and charring zone, heating the withdrawn gases, introducing the resulting heated gases into said heating and charring zone to contact addition- 5 al cellulosic material therein so as to generate additional combustible gas and char material. 7. The process of Claim 6 further comprising at least from time to time combusting a portion of the gases withdrawn from 0 ' said heating and charring zone to produce a hot gaseous com¬ bustion effluent and employing said hot gaseous combustion effluent to heat said withdrawn gases prior to introducing the same into said heating and charring zone. 5 8. A reactor for the heating or drying of powders, grains, chips, and other feed materials comprising: a chamber for containing the feed material to be heated or dried; inlet means at the top of said chamber for depositing said 0 feed material, in said chamber; outlet means at the bottom of said chamber for removing feed material which has been heated or dried; a uniform array of input means vertically disposed -within said chamber across substantially the entire length and ex- 5 tending horizontally across substantially the entixe width ■ *• of said chamber for introducing hot gases therein; and a uniform array of output means vertically disposed within said chamber across substantially the entire length and ex¬ tending horizontally across substantially the entire of said chamber for withdrawing said hot gases and any ga produced within said chamber. 9. The reactor of Claim 8 wherein said uniform array of put means and said uniform array of output means are alte ting rows of inverted V-shaped members. 10. The reactor of Claim 8 wherein said reactor further prises means for regulating the flow of hot gases through uniform array of input means and said uniform array of ou means. 11. An -apparatus for the heating or drying of powders, g chips, and other feed materials which comprises the react Claim 8 and means for pre-heating or drying said feed mat prior to depositing said feed material in said chamber. 12. The apparatus of Claim 11 further comprising means fo conducting the gases which are withdrawn from said chamber ' to said means for pre-heating or drying said feed material 13. The apparatus of Claim 11 further comprising means fo burning combustible gases included within the gases which withdrawn from said chamber. OMPI

Inventors: GROSS F, KNOFFSINGER F, WHITE E
Applicants: ENERCO INC
Application year: 1979
Main classification: C10B49
IPC codes: C10B49, C10B53, F26B17, F26B21, F26B23