FR2563230A1 - Carbonisation ovens and plant for the production of charcoal employing such ovens - Google Patents

Abstract

Charcoal manufacture. Carbonisation oven of the type comprising a body intended to contain wood to be carbonised, with a view to obtaining charcoal, the said body having side openings 8 for allowing the oxidising air to enter, of adjustable cross-section and being closed by a roof 16 provided with a chimney 20 equipped with means for opening or closing the opening 21 for discharging the fumes and regulating the cross-section of the latter, characterised in that the body comprises a lower first part 1 taking the form of a vessel which is open in its upper part, and an intermediate 11 supporting the roof 16, the latter part being broadly dimensioned to slide over the first part 1 while providing a free space between them.

Description

 The present invention relates to a carbonization oven for the production of charcoal.

 The invention also relates to an installation using carbonization ovens.

 Known ovens consist of a metal casing containing the wood with adjustable combustion air intake openings, and smoke evacuation chimneys.

 During the manufacture of charcoal, during a first phase which after ignition corresponds to a dehydration of the wood, one must be able to evacuate the fumes which contain a large quantity of water vapor.

 After this first phase, the smoke evacuation section must be reduced manually or automatically to control carbonization. The quantity of wood has considerably decreased during dehydration, the volume of oxidizing air with respect to the wood is then too large so that a thermal imbalance is created which causes combustion of too much wood. The yield is thus poor due to the quantity of unusable ash.

 In addition, in the carbonization phase, pyroligneous vapors, tars, pitches, oils, acetic acid, etc. are released. which have a high calorific value, are released into the atmosphere, these high temperature vapors not being used.

 The present invention aims in particular to remedy these various drawbacks.

The oven according to the invention is of the type comprising a body intended to contain wood to be charred, with a view to obtaining charcoal, said body having at its base side openings for the combustion air intake of section adjustable, the body being closed by a roof provided with a chimney provided with means for opening or closing the smoke evacuation opening and regulating the section thereof and is characterized in that the body comprises a first lower part affecting the shape of an open tank at its upper part, and an intermediate part supporting the roof, the latter being largely dimensioned to slide on the first part while leaving between them a free space
Thanks to this arrangement, the oven is charged so as to maintain in the high position the intermediate part and during the dehydration and carbonization phases, this part resting by the roof on the wood slides vertically so that the keeps the volume of combustion air inside the oven constant, the carbonization temperature being stabilized.

 After the dehydration phase, the chimney can be closed, which causes an inversion of the smoke evacuation current which then escapes in the interval between the first part and the second intermediate part. This inversion ensures the combustion of pyroligneous vapors and volatile materials, which makes it possible to avoid atmospheric pollution, to reduce the carbonization time and to obtain a good quality and homogeneous charcoal. A higher yield by weight is also obtained by using the calories recovered.

 In order to facilitate filling the oven, the roof is removably mounted on the second intermediate part and the first part includes means for maintaining said intermediate part in an elevated position.

 To obtain good sliding of the in-term part with respect to the lower part, the first part has guide rollers for the second intermediate part.

 Preferably, the oven has a general cubic shape.

 According to a characteristic of detail, the side walls of the first party are doubled and braced.

 Thanks to this arrangement, a thermal bridge is created, the internal wall receiving the thermal shocks is cooled by the external wall which it is in contact with the outside. This ensures a long service life for the equipment and a reduction in deformation due to gunfire.

 To perfect the filtering of the fumes, the chimneys can be internally provided with baffles designed to collect the tars and pitches from the pyrolysis phase, and a filtering element, for example in the form of a charcoal charge. for the retention of pyroligneous vapors (acetone, acetic acid).

 The invention also relates to an installation for the production of see coal using the ovens according to the invention.

 The installation, according to the inventOon, is characterized in that it comprises two ovens arranged one against the other, an enclosure enclosing the two ovens and two chimneys each connected to an oven.

 Thanks to such an installation, the ovens are sheltered from the weather and it is much better to adjust the carbonization in a stable atmosphere. One of the essential aspects of such an installation is the saving of time of the carbonization cycle which is very important. In fact, such an installation is used by lighting an oven, while the neighboring filled oven remains on standby and during the carbonization phase the fumes which result from the combustion of pyroligneous vapors and other volatile substances are automatically recycled for pass through the wood of the oven so that "we proceed to the dehydration phase of said wood. When the charring is tEP- mined in an oven we replace it with another repa i and we light the one whose wood is dehydrated It is thus possible to produce an assembly which operates continuously.

 To facilitate the positioning of the ovens, the enclosure is formed by two mobile cells open on their face opposite one another and linked so as to be able to be brought closer or apart.

 According to a constructive characteristic, each cell is carried by a carriage guided on rails.

 Preferably, each cell has on its walls openings which can be closed by shutters, it is thus very easy to access the ovens to make the various adjustments, in particular air intake.

 There may be provided for each cell a vertically movable flap capable of closing in part-e the open face of the cells, such flaps making it possible to adjust the section for the passage of smoke from an oven in the carbonization phase towards the another oven for dehydrating the wood it contains.

 According to a constructive characteristic, the movable flap is guided in vertical gli-ssters of the edges of the open face of the cell and connected by a cable guided on pulleys to a balancing counterweight.

 According to yet another important characteristic, each cell comprises means for automatically closing the chimney from a determined value of the sliding of the intermediate part of the oven. Thus, the oven can automatically and without manual intervention pass from the dehydration phase to the carbonization phase, by automatic reversal of the flue gas discharge current.

Finally, according to a last characteristic, each cell has an opening in its upper wall intended to be aligned with a duct for evacuating smoke from the oven, said opening being traversed by a movable chimney connected to the duct for discharging smoke from the oven and arranged so that from a determined vertical sliding of the intermediate part the chimney is closed
The invention will now be described in more detail with reference to a particular embodiment given by way of example only and shown in the accompanying drawings, in which
FIG. 1 is a perspective view with cutaway portions of an oven according to the invention,
FIG. 2 is a view in vertical section of the furnace of FIG. 1,
Figures 3 and 4 are sectional views showing the different operating phases of the oven, according to the invention,
Figure 5 shows in section a detail of a variant of the chimney,
FIG. 6 shows in perspective an installation using two ovens according to the invention,
Figures 7, 8 and 9 are schematic views showing the use of the installation of Figure 6.

 The oven shown in Figures 1 to 4 comprises a lower part 1 consisting of a cubic tank having a bottom 2 integral with profiles 3 allowing it to be raised slightly above the ground to allow the oven to be moved, for example using of a forklift.

The bottom 2 has four side walls 4, 5, 6 and 7 which are internally double and which are in the vicinity of their lower edge provided with openings 8, the section of which is adjustable by flaps 9.

 The side walls 5 and 6 are provided with horizontal guide rollers 10 which turn mad.

 The oven is completed by an intermediate body 11 formed of a tubular element of square section and widely dimensioned so as to be able to slide freely on the lower part 1, guided on the rollers 10.

 The intermediate part 11 is secured at its upper part with an L-shaped profile 12, one of the wings 12a is secured to the upper edge, while the other wing 12b forms an outer rim, the latter wing receiving in corresponding threads screws 14.

 The oven is completed by a roof 16 which has a rim 17 intended to rest on the wing 12a inside the perimeter determined by the wing 12b.

 The flange 17 has holes 18 to allow engagement of the screws 14, these holes being able to be tapped.

 The roof 16 has in its central part a chimney 20 having a lateral opening 21 and in which engages a cap 22 formed of a tubular element intended to engage in the chimney 20, said tubular element being pierced with an opening 24 capable of coinciding with the opening 21 and secured to a bottom 23 provided with an operating handle 25.

 The roof 16 is also provided with additional chimneys 26 which can be closed off by flaps 27.

 On the side walls 5 and 6 are pins 30 intended to support the intermediate body 11 during loading of the oven.

 The bottom 2 of the lower part 1 can be bowl-shaped and present in its central part a hatch 31 to facilitate the emptying of the charcoal.

 When loading the roof 16 is removed while the intermediate body 11 rests on the pins 30.

 When the oven is full, the roof is fixed with the screws 14 and the pins 30 are removed, the hearth is then lit and the draft suitably adjusted with the shutters 9, while the chimneys 20 and 26 are open so as to allow the evacuation of humid fumes.

 After a certain time which corresponds to a first phase making it possible to eliminate the humidity (FIG. 2), the chimney 20 and the additional chimneys 26 are closed, there is then (FIG. 3) a change in the current of the fumes, those -this escaping through the interval formed between the part 1 and the intermediate body 11.

 In this phase which corresponds to the pyrolysis, the various hot tar gases, pitch, methyl alcohol, carbon monoxide, methane etc. are burnt inside the oven. which have a calorific value much higher than that of wood and their combustion constitutes an intake of calories which generates a reduction in the consumption of fuel wood.

The fumes pass through the mass of the wood and deposit in it, tars, pitches and volatile matter so that the wood forms a filter which avoids atmospheric pollution
As the carbonization progresses, the intermediate body 11 descends for the end of carbonization to rest on the ground. This arrangement allows the maintenance of a volume of oxidizing air in the oven corresponding to the volume of the wood to be carbonized, which allows homogeneous carbonization to be obtained thanks to the fuel air balance.

 At the end of carbonization, sand is deposited around the furnace and on the chimneys so as to stop carbonization then, after cooling, the charcoal obtained by the hatch 31 is emptied.

 It will be noted that the walls of the body 1 are doubled which makes it possible to create an athermic bridge, the internal walls receiving the thermal shocks due to contact with incandescent charcoal, while the external walls are cooled in contact with air. outside. Thus the various elements constituting the oven have good behavior and a long service life of the equipment is ensured.

 In Figure 5, there is shown in detail in section a variant of the chimney 20 this chimney referenced here in 20a comprise members for filtering the fumes.

 The members corresponding to those of the various figures already described are designated by the corresponding references assigned the letter "a".

 On the roof 16a is fixed to the bayonet a conduit 65 preser.tant stops 66 against which rests a sleeve 67 secured to a cap 23a.

 The sleeve 67 has internal rings 68 and a bottom 41. The face of the cell 39 opposite to that closed by the bottom 43 has a wide opening 45 capable of being partially closed by a flap 46 movable in vertical slides 47 and on the upper edge of which a cable 48 is fixed, guided on pulleys 49 and 50 carried by a bracket 51 and at the free end of which a counterweight 52 is fixed.

 The side walls 40, 41 and the bottom 43 are provided with openings 53 closable by flaps 54.

 The carriage 38 is identical to the carriage 37 and the references used for the carriage 37 have been shown in the drawings to designate the same members.

 Each cell 39 has at its upper part an opening 56 in which a chimney 57 is slidably mounted having at least one lateral opening 58 and closed by a cap 59 provided with a flange 60 intended to circumscribe the edge of the opening 56.

 Between the rails 35 and 36 at locations determined and marked by marks, not visible in the drawings, are placed one next to the other two ovens A and B such as that described and represented in the different figures 1 to 4.

The cells 39 of the carriages 37 and 38 are approached from one another so as to enclose the two ovens and the flaps 46 more or less lowered according to the settings to be provided. The chimneys 57 are of a considerable length so as to be able to slide freely in the openings 56 and to rest on the roofs 16 of the ovens by fitting onto the chimneys 20 thereof.

The length of the chimneys 57 corresponds to the displacement of the intermediate body 11 during the phase corresponding to the ignition, combustion and dehydration of the wood to be charred, so that at the end of the dehydration phase when the wood must be charred, rim 60 rests on the wall 42 and that thus the chimney being closed, the fumes are directed into the space formed between the body 11 and the
lower part 1.

the internal lateral wall of the sleeve comprises a grid 69 supporting a column 70 provided with lateral fins 71 which form, with the rings 68, baffles.

 The sleeve 67 in the vicinity of the cap 23a has openings 24a and between the latter and the grid 69 there is provision for a capacity 76 which can receive a filtering element 77, for example carbon charcoal.

 The filter element can be placed in a basket or cartridge to facilitate periodic replacement and either the grid 69 or the cap 23a being removable for this purpose.

The cap 23a is provided with a handle 25a and
Presents a skirt 78 which is intended to cooperate with a groove 80 formed in the upper surface of the roof 16a to ensure the struggle when the first phase of elimination of moisture is completed and the oven goes to the carbonization phase.

 Such a chimney allows by the baffles the retention of the tars by projection and by the filtering element 77 the retention of the pyroligneous vapors (acetone, acetic acid).

 In Figures 6 to 9, there is shown an installation which allows an appreciable time saving by using three ovens, according to the invention.

 In fact, if you use a single oven, you must plan the loading time, the ignition and combustion time, the dehydration time, the carbonization time and the cooling time, the latter being approximately 24 hours. .

 The installation makes it possible to considerably reduce the first phase and thus to have an increased production.

 The installation comprises two rails 37 and 38, on which two carriages 37 and 38 roll.

The carriage 37 supports a cell 39 having two side walls 40 and 41 an upper wall 42 and
The operation of the installation is as follows: the two charged ovens A and B are placed one against the other and the cells 39 form an enclosure in which the ovens A and B are enclosed. The oven A is on and by the flaps 54, which are largely dimensioned, it is possible to have access to the flaps 9 (FIG. 7).

 During the first phase (ignition, combustion and dehydration), the fumes charged with water vapor escape through the chimney 57.

 When the intermediai-re body 11 has slid down a certain height, the chimney 57 closes automatically by abutting against the wall 42 by its rim 60, and the oven A passes into the carbonization phase, the fumes then circulating in passing through the space provided between the intermediate body 11 and the lower part 1 (FIG. 8).

As the fumes cannot escape from the cells but the chimney 57 of the oven B is open as well as the flaps 9 thereof> there is a draft through the oven B of
so that the hot gases which are at a temperature of the order of 360 "and which have a high calorific value by passing through the wood of the oven B dry it which which, subsequently, will considerably reduce the consumption of fuel wood. When the carbonization phase of the oven A is finished, the cells 39 are removed and with a lifting member it is removed from its initial location to place it on a cooling area, sand being placed all around and on the roof 16 to plug the various openings (see figure 4).

 Another oven C has been previously charged and we live, with the lifting device place it in the place previously occupied by the oven A. We close the cells 39, we adjust the shutters 46, and we turn on the oven B.

 The dehydration phase of the oven B is very short because it was carried out during the carbonization phase of the oven A since the fumes which pass through the wood ensure the drying thereof. When oven B goes into the carbonization phase, the fumes pass through the wood of oven C and ensure its dehydration (Figure 9).

 During these dehydration phases carbonization of the ovens C and B, the oven A is cooled, de-energized from the charcoal it contains and filled with wood, then, the oven B is removed when the carbonization of the wood thereof is finished and the oven A is placed in the place occupied by the oven B and we proceed in the manner described above.

 It is understood that with only three ovens and the installation according to the invention, it is possible to continuously manufacture charcoal without dead time, which allows rational and optimal use of the ovens.

 Such an installation has, in addition to the very significant time saving, for obtaining charcoal, numerous advantages.

 In fact, the pyroligneous vapors, tars and acetic acid being channeled into the mass of wood to be dehydrated are retained therein and their discharge into the atmosphere is avoided.

 The cells 39 form a stabilized enclosure which avoids draft adjustments and a better yield is thus obtained.

 Since no precise adjustment is necessary, a specialized workforce is not necessary.

 it is not necessary to monitor the ovens at night.

 In addition, the calories which are normally lost are recovered by radiation from the walls of the oven in operation.

 We can work in any weather since the ovens are protected from the weather and operate in a stable atmosphere.

 Of course, the invention is not limited to the embodiment which has just been described and shown. Many modifications of details can be made without departing from the scope of the invention.

Claims (2)

 1 "- Carbonization oven of the type comprising a body intended to contain wood to be carbonized, with a view to obtaining charcoal, said body having at its base side openings (8) for admission of combustion air from adjustable section and being closed by a roof (16) provided with a chimney (20) provided with means for opening or closing the discharge opening (21) of the fumes and regulating the section thereof, characterized in that the body has a first lower part (1) affecting the shape of an open tank at its upper part, and an intermediate part (11J supporting the roof (16) the latter being largely dimensioned to slide on the first part (1 ) by creating a free space between them.  2 - carbonization oven according to claim 1, characterized in that the roof (16) is removably mounted on the second intermediate part (11) and the first part comprises means (30) for holding said intermediate part (11) in an elevated position.  30 Carbonization oven, according to claim 1, characterized in that the first part (1) comprises rollers (10) for guiding the second intermediate part (11).  4 "- Carbonization oven, according to claim 1, characterized in that it has a generally cubic shape.  5 "- Carbonization oven according to claim 1, characterized in that the side walls of the first part (1) are doubled and braced.  (68, 71) and a filter element (77).  6 "- Carbonization oven, according to claim 1, characterized in that the chimney (20a) comprises baffles  7 "- Installation for manufacturing charcoal, using ovens, according to claim 1 and / or any one of claims 2 to 6, characterized in that it comprises two ovens (A, B) arranged one against the other, an enclosure (39) enclosing the two ovens (A, B) and two chimneys (57) each connected to an oven (A, B).  8 - installation for manufacturing charcoal, according to claim 7, characterized in that the enclosure (39) is formed by two cells (39) movable open on their face opposite one of the other and guides so that they can be brought closer or apart.  94- Installation for manufacturing charcoal, according to claim 8, characterized in that each cell (39) is carried by a carriage (38) guided on rails (35 and 36).  10'- charcoal manufacturing installation according to claims 7 and 8, characterized in that each cell (39) has on its walls openings (53) closable by shutters (54).  11 "- Installation for manufacturing charcoal according to claims 7 and 8> characterized in that each cell comprises a movable flap (46) capable of partially closing its open face (45).  120- Charcoal manufacturing installation according to claim 11, characterized in that the movable flap (46) is guided in vertical slides (47) of the edges of the open face (45) of the cell (39) and connected by a cable (48) guided on pulleys (49 and 50) to a counterweight (52) for balancing.  13 - installation for manufacturing charcoal, according to claim 8, characterized in that each cell comprises means for the automatic closing of the chimney from a determined value of the sliding of the intermediate part (11) of the oven.  the chimney is closed.  14 - installation for manufacturing charcoal, according to claim 13, characterized in that each cell has an opening (56) in its upper wall (42) intended to be aligned with a duct (20) for evacuating smoke from the oven, said opening (56) being traversed by a movable chimney (57) connected to the duct (20) for evacuating smoke from the oven and arranged so that from a determined vertical sliding of the intermediate part (11)