[0001] The present invention relates to a device for the gasification of wood and, in general,
is part of the technology of apparatuses by means of which a solid fuel, in this case
a biomass consisting of wood, is only partially oxidised in order to obtain a combustible
gas.
[0002] Research on renewable energy sources proposes the gasification of wood as one of
the most interesting, considering the quantity of discarded wood available in industrial
societies and the fact that at least 50% of this discarded wood is simply dispersed
by burning it or even distributing it over the ground, causing permanent damage to
the environment.
[0003] As indicated above, the gasification of a wooden biomass is a thermochemical process
based on the partial oxidation of vegetable carbon and the breakdown of the products
deriving from the thermal decomposition of the biomasses, including the decomposition
of the water absorbed by the original biomass and that of formation. This reaction
is followed by reduction of the carbon dioxide on a bed of incandescent pure carbon
automatically generated by the previous reaction.
[0004] The above-mentioned reactions occur under conditions of thermal equilibrium, with
a production of heat sufficient to allow the thermochemical process to supply its
own energy, without the aid of external energy sources. The set of reactions which
break down the biomass into simple elements of the pyroligneous derivatives is that
characteristic of wood chemistry, although the quantity varies according to the type
and characteristics of the biomass gasified.
[0005] The device forming the subject-matter of the present invention comprises, in particular,
a reactor in which the above-mentioned gasification process which, to summarise, envisages
the drying, pyrolisis, carbonisation and gasification of the solid wooden biomass,
is effected according to a procedure generally known as the "Imbert process".
[0006] This type of process envisages the use of a vertical gasification device in which
the wood, fed in continuously from the top of the device, gradually moves towards
the base, undergoing said gasification with concurrent flow; that is to say, in which
the gaseous flow of the products of the reaction, of the water vapour, of the fuel,
and finally of the comburent atmospheric air, all follow the direction from top to
bottom.
[0007] The device is of the type comprising vertical outer walls, a head and a base which
together form a long tank with a vertical longitudinal axis; a heating zone inside
the tank, near the base, this zone being surrounded by lower portions of the walls
of said tank; a plurality of comburent air conveyor elements, located in the oxidation
zone and in fluid communication with an external air source, so that the air can be
transferred from the air source to the oxidation zone; a discharge zone for the gas
produced by the reactor, normally called the neck, located below the conveyor elements
and having a hole that allows the discharge of the gas to the outside of the tank.
[0008] Gasifier devices of the above-mentioned type are already described in documents US
5 226 927 and EP 0693545 A1.
[0009] The main disadvantage of such types of wood gasification devices is the high content
of dust and tar transported by the gas, which, downstream of the reactor, require
expensive and not completely effective filtration plants, envisaged to make the gas
suitable for use in internal combustion engines. The tar content produced in the gasifier
device reactor is in inverse proportion to the local oxidation-reduction reaction
temperatures.
[0010] In conventional Imbert reactors, in particular, the comburent air conveyor elements
are distributed over the walls of the reactor in such a way that they lie on a horizontal
plane and are all oriented so as to direct the air conveyed by each of them exactly
to a central point of the heating zone.
[0011] The discharge zone, called the neck, has a twin truncated cone structure, in which
the smaller bases of the two truncated cones are opposite one another and are joined
at a narrow central zone, in which the discharge hole or neck is located.
[0012] Due to the high temperatures of the gas (1000 - 1400 °C); the high chemical reactivity
of the gas; its strong abrasive action caused by the speed and the large amount of
dust transported, the nozzles are made of special, high-alloy steels, which are stainless
and resistant to high temperatures.
[0013] For these main reasons, the reactor operating temperature is limited, in use, to
the maximum temperature sustainable by the nozzle and the materials of which the reactor
core is made. The reactor core, therefore, constitutes a critical element for further
raising the reactor general operating temperatures and requires complex construction
solutions that are expensive to maintain, since despite the careful selection of construction
materials, the reactor is subject to rapid deterioration of its mechanical characteristics,
thus requiring necessary and frequent stopping of the gasifier plant in which the
reactor is installed and complex reactor part substitutions.
[0014] In addition to the need to contain the operating temperatures, as indicated above,
an equally critical question is the local non-uniformity in the thermal and dynamic
conditions of the transit of the effluents in the reaction zone: cold veins and overheated
zones subject the metal walls of the zone in question to thermal stress, causing rapid
mechanical deterioration.
[0015] It is also known from documents CH-A-227948, US-A-4459136, FR-A-901589 and NL-A-8900939
devices for the gasification of wood.
[0016] In detail, both documents CH-A-227948 and US-A-4459136 show an apparatus for dryng,
pyrolizing and also gasifying of wood comprising an outer container, an inner casing
having an upper cylindrical section and a reactor zone presenting an oxidation zone
and a discharge zone. The discharge zone presenting a diaphragm, a discharge hole
in which pass a gaseous fluid and a plurality of fluid conveyor elements to supply
flow of air. A part of the solid particles rests on the diaphragm while the gaseous
flow bringing some solid particles pass through the discharge hole. Document FR-A-901589
shows a device of the type above disclosed but it does not show a diaphragm to ,mantain
the solid particles and the fluid conveyor elements.
[0017] Regarding to document NL-A-8900939 it is shown an apparatus for driyng, pyrolizing
and also gasifying wood, comprising an outer container, an inner casing having an
upper cylindrical section and a reactor zone presenting an oxidation zone and a discharge
zone. The discharge zone presenting a discharge hole in which pass a gaseous fluid
and a plurality or fluid conveyor elements to supply flow of air and directed in the
upper portion of the oxidation zone. It is to be noted that in this document the solid
particles fall with the gaseosus flow through the discharge hole and rest on the surface
of the bottom of the outer container.
[0018] The aim of the present invention is to overcome the above-mentioned disadvantages,
allowing the creation of gasifier devices in which the relative reactors are able
to operate without disadvantages at operating temperatures that are higher than those
that can currently be reached and substantially uniform in a manner that was impossible
using conventional plant.
[0019] In accordance with the present invention, this aim is achieved by a gasifier device
comprising a reactor in which the fluid conveyor elements or comburent conveyor nozzles
are oriented in such a way that a flow of air is sent to the oxidation zone, said
flow of air imparting to the gaseous mixtures and reagents produced in the reactor
a rotary motion about the longitudinal axis of the gasifier, in addition to the conventional
forward motion, towards the discharge zone or neck, directed parallel with said longitudinal
axis. The reactor reaction zone also comprises a diaphragm held crossways by the reactor
walls, said diaphragm having a discharge hole.
[0020] Together with the adjacent reactor walls, the diaphragm delimits a duct with a through-section
whose shape varies suddenly, creating a situation in which the dynamics of the gases
in transit are similar to those of the cyclone effect. The gas drawn by the flow of
air sent by the conveyor elements moves forwards, turning about the longitudinal axis
and, at the moment in which it is intercepted by the diaphragm and forced to pass
through the discharge hole or neck with smaller diameter, is subjected to a violent
acceleration that separates the solid particles which it transports, causing them
to be deposited on the vertical walls of the reactor and on the surface of the diaphragm.
The solid particles settle in a funnel shape and coat the walls of the diaphragm and
the connecting zone between the diaphragm and the inner walls of the reactor with
refractory material as far as the nozzles.
[0021] The coating, consisting of ash, of which the surface is in a melted paste state,
is deposited, drips and is continuously regenerated during the turbulent gasification
process, thus protecting the metal walls of the reactor from heat and, lacking cohesion,
from mechanical stress.
[0022] The gasifier device is also equipped with heat exchangers with fins which, applied
to the outer wall of the inner container or tank, allow partial recovery of the heat
energy carried by the exiting gas and containment of its temperature, improving the
energy equilibrium of the gasification reaction by raising the general tank temperatures,
raising the oxidation-reduction temperatures and drying the wood which, therefore,
does not have to be pretreated outside the gasifier device.
[0023] The top of the gasifier device is fitted with a head vapour condenser, which allows
any excess humidity in the raw wooden biomass to be condensed and extracted.
[0024] Raising of the reactor operating temperatures and the reduction of the risk of cold
veins in the reagent gases allows maximised breaking of the heavy chains deriving
from the tar and pyroligneous oils into light, volatile chains, comprising gaseous
hydrocarbon fractions and into simple carbon and hydrogen elements.
[0025] The resulting cleanness and stability of the gas produced by this reactor is directly
relevant in the plant construction economics, allowing the complexity and costs of
complicated and inefficient purification apparatus conventionally upstream of the
engines that use the wood gas to be reduced to a minimum.
[0026] In accordance with the above-mentioned aims, the present invention also provides
a gasification method implemented by the device equipped with the reactor made according
to the present invention.
[0027] The technical characteristics of the invention according to the above-mentioned aims
are described in the claims below and its advantages are apparent from the detailed
description which follows, with reference to the accompanying drawings which illustrate
preferred embodiments of the invention and in which:
- Figure 1 is an assembly view of a gasifier device made in accordance with the present
invention;
- Figure 2 is a cross-section of the reactor illustrated in Figure 1, according to a
plane II - II;
- Figure 3 is a cross-section of the reactor illustrated in Figure 1, according to a
plane III - III;
- Figure 4 is a scaled-up cross-section of a first detail of the reactor illustrated
in Figure 1;
- Figures 5 and 6 are respectively a scaled-up elevation view and a scaled-up top plan
view of a second detail of the reactor illustrated in Figure 1;
- Figures 7 and 8 are respectively two cross-sections of a third detail of the reactor,
illustrated according to planes VII - VII and VIII - VIII;
- Figure 9 is a partial view of the reactor, schematically illustrating a characteristic
reactor operating condition.
[0028] With reference to the accompanying drawings, Figure 1 illustrates a gasifier device,
labelled as a whole with the numeral 1, envisaged for the production of combustible
gas from a wooden biomass, by means of a thermochemical process based on the partial
oxidation of vegetable carbon and the thermal decomposition of the pyroligneous compounds
deriving from the thermal decomposition of the biomasses, and also relative to the
decomposition of the water absorbed by the original biomass and that of formation.
[0029] The above-mentioned thermochemical treatment is carried out by the device 1, in accordance
with the "IMBERT" process with concurrent flow, therefore, the device 1 comprises
a long, cylindrical outer container 2, substantially vertical, with a vertical outer
side wall 3, a head 5 and base 6, connected to one another.
[0030] The outer container 2 houses a tubular inner casing 4. The inner casing 4 is mounted
within the outer container 2 at a distance designed to delimit a gap 17 between them,
and they are positioned axial to one another on a shared vertical, longitudinal axis
2a.
[0031] The outer container 2 is basically cylindrical. The inner casing 4 is made of stainless
steel, resistant to high temperatures and the chemical action of the process gases
and has two cylindrical end sections 4a and 4b, with different diameters, joined to
one another by an intermediate truncated cone portion or hopper 4c, which connects
the upper cylindrical section 4a with larger diameter, to the lower cylindrical section
4b with smaller diameter. Near the base 6, the inner casing 4 houses a biomass oxidation
zone 7, at the lower cylindrical section 4b of the casing 4 and equipped with a plurality
of fluid conveyor elements or nozzles 8 and a zone 9 for discharge of the gas towards
the outside of the casing 4.
[0032] The conveyor elements 8 (Figure 2) comprise a set of nozzles which: are distributed
over the wall of the lower cylindrical section 4b; are coplanar with one another and
located on a basically horizontal plane; and are connected with a ring-shaped chamber
10 that encompasses the lower cylindrical section 4b of the inner casing 4. The ring-shaped
chamber 10 is connected to an external air source 21 (schematically illustrated in
the figures) by a connector 11, so that the air is transferred from the source 21
into the oxidation zone 7 by the nozzles 8.
[0033] The unit comprising the lower cylinder 4b, ring-shaped chamber 10 and nozzles 8,
constitutes the so-called reactor 22.
[0034] The conveyor elements 8 are oriented on the wall of the lower cylindrical section
4b in such a way that they respectively direct the flow of air 8f conveyed by each
of them tangentially to a horizontal circle 12 centred on the longitudinal axis 2a
(see also Figure 7).
[0035] The discharge zone 9, located below the conveyor elements 8, comprises a flat, ring-shaped
diaphragm 13, through the centre of which there is a cylindrical discharge hole 14
(Figure 4). The diaphragm 13 is supported crossways by the lower cylindrical section
4b of the inner casing 4 and, approximately half way down the casing, by means of
a ring-shaped washer 15 (Figures 5 and 6), which connects the diaphragm 13 to the
wall of the lower cylindrical section 4b.
[0036] Due to the orientation of the conveyor elements 8, the flow of fuel air 8f fed into
the oxidation zone 7 imparts to the gaseous flow 8g in which the gases and solid particles
generated in the gasification process flow together, a rotation about the longitudinal
axis 2a.
[0037] Since the reactor 22 is of the type with concurrent flow, as it rotates, the gaseous
flow 8g simultaneously moves along the longitudinal axis 2a of the lower cylinder
4b, towards the discharge zone 9 below. As a result of the cylindrical shape of the
lower section 4b of the inner casing 4, and of the shape and position of the diaphragm
13 inside said section, the above-mentioned elements (diaphragm 13, washer 15 and
walls of the lower cylindrical section 4b) together form a transit duct, whose through-section
is suddenly reduced at the discharge hole 14.
[0038] As it advances along the longitudinal axis 2a, the flow of gases 8g is intercepted
by the diaphragm 13 and washer 15, undergoing a modification in its fluid dynamics,
which creates a fluid stagnation in the zones of the transit duct closest to the connecting
zone between the diaphragm 13 and the inner wall of the casing 4.
[0039] The solid particles transported by the gaseous flow 8g are, therefore, deposited
on the diaphragm 13, on the washer 15 and on the vertical inner wall of the lower
cylindrical section 4b of the reactor 22, gradually coating them with a mass 16 of
particles (Figure 9) which are deposited and accumulate in controlled, regular shapes,
which in the case illustrated in the figure are represented by truncated cones set
opposite one another.
[0040] The masses 16 of particles deposited on the vertical inner wall of the lower cylindrical
section 4b constitute, as indicated above, a mass 16 with the shape of a funnel of
particles, in a melted paste state on the surface, and basically comprise ash and
coal dust.
[0041] These provide heat insulation for the diaphragm 13, washer 15 and the portions of
the inner wall of the lower cylindrical section 4b adjacent to them and reduce the
dispersion of heat to the outside of the casing 4 at its hottest zone, comprising
the oxidation zone 7 of the reactor 22. Moreover, they cause a reduction in the actual
wall temperature reached by the metal surfaces at the oxidation zone 7 and prevent
the hot gases from cooling by touching the metal surfaces of the washer 15 and diaphragm
13 wall, with the obvious exception of the portion of the surface relative to the
discharge hole 14.
[0042] The diaphragm 13, washer 15 and hole 9 assembly is followed by a further portion
of the lower cylindrical section 4b, which forces the gases to make contact for longer
periods with the reducing carbon masses which fill the gap 17.
[0043] It should also be noticed that, with the reactor 22 operating, the masses 16 of ash
also form downstream of the diaphragm 13, following the sudden widening of the cross-section
encountered by the gaseous flow that exits the discharge hole 14 below the diaphragm
13.
[0044] The masses 16 of ash located below the diaphragm 13 also remain stably in position
during continuous operation of the reactor 22.
[0045] If said masses 16 were to precipitate towards the base 6 of the outer container 2
due to the effects of gravity, for example, if operation of the reactor 22 were interrupted,
following restarting of the reactor 22, the masses 16 would reform automatically and,
after a brief period of time, would continue to carry out their coating and insulating
function.
[0046] The technical characteristics of the above-described reactor 22 allow the obtainment
of all of the advantages that can be linked to an increase in and a more uniform distribution
of the operating temperatures of the reactor 22.
[0047] The increase in and homogeneous distribution of the temperatures is allowed, on one
hand, by an increased heat resistant capacity of the walls of the lower cylinder 4b
and diaphragm 13, and on the other hand, by reduced heat dispersion from the oxidation
zone 7 to the outside of the container 2. As regards the actual shape of the flow
conveyor elements 8, the above description refers to tubular nozzles; however, many
alternative embodiments are possible, with equivalent functions. One possible alternative
embodiment, shown by way of example only in Figures 7 and 8, shows that the conveyor
elements 8 may comprise simple holes 8', which in the example illustrated are round,
made in the wall of the lower cylindrical section 4b of the inner casing 4 and oriented
in such a way that they are offset according to angles α designed to direct the flow
of air 8f eccentrically relative to the longitudinal axis 2a of the container 2.
[0048] With reference to Figure 1, it can be seen that within the gap 17 between the outer
container 2 and the inner casing 4, at the upper cylindrical section 4a, the outer
container 2 is fitted with a heat exchanger 18 to recover at least part of the heat
carried by the gases that flow out of the inner casing 4. The heat exchanger 18 (see
also Figure 3) comprises a plurality of flat, rectangular fins 19, attached vertically
to the innermost casing 4 of the device 1. The fins 19 are distributed evenly along
the outer edge of the inner casing 4 and project into the gap 17, protruding radially
towards the outermost casing 3. The gases that flow out of the inner casing 4 through
the discharge hole 14 are caused to rise up through the gap 17 from the base 6 to
the head 5. As they pass through the heat exchanger 18, the gases touch the fins 19
and, cooling, give up part of their heat which, through the wall of the upper cylindrical
section 4a of the inner casing 4, is transferred to the biomass still to be treated,
that in the meantime is moving downwards inside the inner casing 4 and proceeds from
the head 5 to the base 6, gradually being dried and subjected to a carbonisation pre-treatment.
[0049] The heat exchanger 18 allows not only the advantage of recovering heat useful to
the thermal equilibrium of the process, but also heats the biomass stored in the upper
cylindrical section 4a of the inner casing 4, promoting its drying, the formation
of water vapour that enters the general concurrent flow of treated compounds and,
finally, allowing an advantageous reduction in the temperature of the gases exiting
the reactor 22.
[0050] The head 5 of the device 1 is fitted with a vapour condenser 20, which allows the
adjustable separation and elimination of any excess humidity in the biomass.
[0051] In operation, the device 1 envisages the insertion of the wooden biomass to be treated
in the upper cylindrical section 4a, through the head 5. The biomass, therefore, constitutes
a column of layered material, which gradually descends along the axis 2a of the inner
casing 4 and, during this movement, is dried at the top of the upper cylindrical section
4a, carbonised at the bottom of the cylindrical section 4a and of the truncated cone
connector or hopper 4c and, finally gasified at the lower cylindrical section 4b of
the inner casing 4. As the column of material descends inside the casing 4, the size
of the biomass is gradually reduced, so that the product exiting the lower cylindrical
section 4b is represented only by the gases and the ash generated in the partial combustion
and by the fragments of pure carbon with a smaller cross-section than the discharge
zone 9 of the diaphragm 13. Part of the ash is deposited on the base 6 of the outer
container 2, from which it is extracted using conventional extraction means, not illustrated.
[0052] The ash which remains suspended in the gas is eliminated by means of a battery of
filters, again not illustrated, as they do not form part of the present invention,
located downstream of the device. Finally, the gases exiting the battery of filters
are sent on for use, for example, to fuel internal combustion engines that drive generators.
[0053] The invention thus designed allows full achievement of the aim of economically obtaining,
with reduced running costs, a gas from which the dust and tar have been removed to
a degree suited to the construction specifications of conventional engines for the
generation of electrical or mechanical energy.
[0054] Moreover, the device with the relative reactor operating in accordance with the method
described, is more adaptable to the chemical-physical characteristics of wood, with
increased operating flexibility of the gasification device.
1. A device for the gasification of wood, comprising an outer container (2), an inner
casing (4), both having a vertical longitudinal axis (2a), a head (5) and a base (6),
said inner casing having an upper cylindrical section (4a), a hopper (4c) and a lower
section (4b); an oxidation zone (7), being positioned inside the lower section (4b)
of the inner casing (4) near the base (6); a plurality of fluid conveyor elements
(8, 8'), being positioned at the oxidation zone (7) and in fluid communication with
an external air source (21), so that the air can be transferred from the air source
(21) to the oxidation zone (7), the fluid conveyor elements (8, 8') being oriented
in such a way that they send into the oxidation zone (7) a flow of air (8f) which
generates a gaseous flow (8g) containing the gases generated, said lower zone (4b)
and oxidation zone defining a reactor (22); a zone (9) for the discharge of the gas
produced by the reactor (22), being located below the conveyor elements (8, 8') and
having a hole (14) for the discharge of the gas to the outside of the inner casing
(4); the discharge zone (9) comprising a diaphragm (13), being attached to the lower
section (4b) of the inner casing (4) across the Longitudinal axis (2a) and having
said discharge hole (14), the diaphragm (13) together with the inner walls of the
lower section (4b) delimiting a transit duct for the gaseous flow (8g) with a cross-section
that varies suddenly, in which the gaseous flow (8g) is intercepted by the diaphragm
(13) and diverted to the discharge hole (14), said interception causing the gaseous
flow (8g) to release solid particles that accumulate on the diaphragm (13) and the
adjacent vertical inner walls of said section (4b), remaining there and at least partially
insulating them against heat and protecting them from direct contact with the following
gaseous flow (8g) that passes through the transit duct and the discharge hole (14);
the device characterized in that the conveyor elements comprise tubes (8) oriented tangentially to a shared circle
(12) to rotates the gaseous flow (8g) about the longitudinal axis (2a) and simultaneously
moving forwards towards the discharge zone (9) parallel with the longitudinal axis
(2a).
2. The device according to claim 1, characterised in that the conveyor elements comprise holes (8') made in the walls of the section (4b) of
the inner casing (4).
3. The device according to claim 1, characterised in that the conveyor elements (8, 8') and circle (12) are coplanar.
4. The device according to claim 1, characterised in that the lower section (4b) has the shape of a cylindrical tube and comprises a diaphragm
(13), being supported by a flat ring (15), the latter being supported across the longitudinal
axis (2a) by the inner walls of the lower section (4b) of the inner casing (4).
5. The device according to claim 1, characterised in that the inner casing (4) and outer container (2) are mounted coaxial to one another,
being separated in such a way that, together, they delimit a gap (17), said gap (17)
being transited by the gaseous flow (8g) that flows out of the discharge hole (14).
6. The device according to claim 5, characterised in that the gap (17) is fitted with heat exchange fins (19), being attached to the inner
casing (4).
7. A method for the gasification of wood comprising the steps of:
- introducing a woodden biomass to be treated in a upper cylindrical section (4a)
of a device (1), which comprises an outer container (2), an inner casing (4), both
having a vertical longitudinal axis (2a), a head (5) and base (6), said inner casing
presenting the upper cylindrical section (4a), a hopper (4c) and a lower section (4b);
an oxidation zone (7) being located within the lower section (4b) of the inner casing
(4) near the base (6); a plurality of fluid conveyor elements (8, 8') oriented tangentially
to a shored circle (12) being positioned at the oxidation zone (7) and in fluid communication
with an external air source (21), so that the air can be transferred from the air
source (21) to the oxidation zone (7), said lower section (4b) and oxidation zone
defining a reactor (22); a zone (9) for the discharge of the gas produced by the reactor
(22), being located below the conveyor elements (8, 8') and having a hole (14) for
the discharge of the gas to the outside of the inner casing (4);
- drying the woodden biomass at the top of the upper cylindrical section (4a);
- carbonizing the woodden biomass dried at the bottom of the cylindrical section (4a);
and
- gasifying the woodden biomas carbonized at the lower cylindrical section (4b) of
the inner casing (4); characterized in that the step of gasifying the woodden biomass comprises the stages of:
- imparting to the gaseous flow (8g) containing the gases generated by the reactor
(22) a rotary motion about the longitudinal axis (2a) and simultaneously a forward
motion towards a discharge zone (9) to the outside of the inner casing (4);
- intercepting the flow (8g) with a diaphragm (13) oriented across the longitudinal
axis (2a) and being shaped so that, together with the adjacent inner walls of the
lower section (4b), it constitutes a transit duct, having a through-section that varies
suddenly, in which the flow (8g) is intercepted by the diaphragm (13) and suddenly
diverted towards a discharge hole (14), said intercepting stage causing the release
of solid particles that accumulate on the diaphragm (13) and the vertical inner walls
(4) of the lower section (4b), coating them at least partially so as to provide them
with heat insulation and prevent the gascous flow (8g) from making direct contact
with the diaphragm (13) and the walls (4) of the lower section (4b).
1. Vorrichtung zur Vergasung von Holz, enthaltend einen äusseren Behälter (2), ein inneres
Gehäuse (4), beide mit vertikalen Längsachsen (2a), einen Kopf (5) und eine Basis
(6), wobei das innere Gehäuse einen oberen zylindrischen Abschnitt (4a), einen Trichter
(4c) und einen unteren Abschnitt (4b) aufweist; einen Oxidationsbereich (7), angeordnet
im Inneren des unteren Abschnittes (4b) des inneren Gehäuses (4) dicht an der Basis
(6); eine Anzahl von Förderelementen (8, 8') des Fluids, die an dem Oxidationsbereich
(7) angeordnet sind, und die Strömungsverbindung mit einer äusseren Luftquelle (21)
stehen, so dass die Luft von der Luftquelle (21) her in den Oxidationsbereich (7)
eingeleitet werden kann, wobei die Förderelemente (8, 8') des Fluids auf solche Weise
orientiert sind, dass sie in den Oxidationsbereich (7) einen Luftstrom (8f) senden,
welcher eine die erzeugten Gase enthaltende gasförmige Strömung (8g) erzeugt, wobei
der genannte untere Bereich (4b) und der Oxidationsbereich einen Reaktor (22) bilden;
einen Bereich (9) zum Auslassen des durch den Reaktor (22) produzierten Gases, welcher
unterhalb der Förderelemente (8, 8') angeordnet ist und eine Bohrung (14) zum Auslassen
des Gases nach ausserhalb des inneren Gehäuses (4) aufweist; wobei der Auslassbereich
(9) ein Diaphragma (13) enthält, das an dem unteren Abschnitt (4b) des inneren Gehäuses
(4) quer zu der Längsachse (2a) angebracht ist und die genannte Auslassbohrung (14)
hat, wobei das Diaphragma (13) zusammen mit den Innenwänden des unteren Abschnitts
(4b) eine Durchlaufleitung für die gasförmige Strömung (8g) eingrenzt, und zwar mit
einem Querschnitt, der sich sprunghaft verändert, und in welcher die gasförmige Strömung
(8g) durch das Diaphragma (13) abgefangen und zu der Auslassbohrung (14) abgeleitet
wird, wobei das genannte Abfangen bewirkt, dass die gasförmige Strömung (8g) feste
Partikel freigibt, die sich auf dem Diaphragma (13) und an den angrenzenden, vertikalen
Innenwänden des genannten Abschnittes (4b) ansammeln, wo sie dann verbleiben und diese
wenigstens teilweise gegen Hitze isolieren und vor dem direkten Kontakt mit dem folgenden
gasförmigen Strom (8g) schützen, der durch die Durchlaufleitung und die Auslassbohrung
(14) geht; wobei die Vorrichtung dadurch gekennzeichnet ist, dass die Förderelemente Rohre (8) enthalten, orientiert tangential zu einem gemeinsamen
Kreisumfang (12), um die gasförmige Strömung (8g) um die Längsachse (2a) zu drehen
und gleichzeitig weiter vorwärt zu dem Auslassbereich (9) hin parallel zu der Längsachse
(2a) zu bewegen.
2. Vorrichtung nach Patentanspruch 1, dadurch gekennzeichnet, dass die Förderelemente Bohrungen (8') enthalten, die in die Wände des Abschnittes (4b)
des inneren Gehäuses (4) eingearbeitet sind.
3. Vorrichtung nach Patentanspruch 1, dadurch gekennzeichnet, dass die Förderelemente (8, 8') und der Kreisumfang (12) koplanar sind.
4. Vorrichtung nach Patentanspruch 1, dadurch gekennzeichnet, dass der untere Abschnitt (4b) die Form eines zylindrischen Rohres hat und ein Diaphragma
(13) enthält, getragen von einem flachen Ring (15), wobei letzterer quer zu der Längsachse
(2a) von den Innenwänden des unteren Abschnittes (4b) des inneren Gehäuses (4) gehalten
ist.
5. Vorrichtung nach Patentanspruch 1, dadurch gekennzeichnet, dass das innere Gehäuse (4) und der äussere Behälter (2) koaxial zueinander montiert sind,
voneinander auf solche Weise getrennt, dass sie zusammen einen Zwischenraum (17) beschreiben,
wobei der genannte Zwischenraum (17) von der aus der Auslassbohrung (14) ausfliessenden
gasförmigen Strömung (8g) durchlaufen wird.
6. Vorrichtung nach Patentanspruch 5, dadurch gekennzeichnet, dass der Zwischenraum (17) mit Wärmeaustauschrippen (19) versehen ist, angebracht an dem
inneren Gehäuse (4).
7. Methode zur Vergasung von Holz, enthaltend die folgenden Phasen:
- Einfüllen einer zu behandelnden Holz-Biomasse in einen oberen zylindrischen Abschnitt
(4a) einer Vorrichtung (1), welche einen äusseren Behälter (2), ein inneres Gehäuse
(4), beide mit einer vertikalen Längsachse (2a), einen Kopf (5) und eine Basis (6)
enthält, wobei das genannte innere Gehäuse einen oberen zylindrischen Abschnitt (4a),
einen Trichter (4c) und einen unteren Abschnitt (4b) aufweist; wobei ein Oxidationsbereich
(7) im Inneren des unteren Abschnittes (4b) des inneren Gehäuses (4) dicht an der
Basis (6) vorgesehen ist; wobei eine Anzahl von Förderelementen (8, 8') des Fluids,
orientiert tangential zu einem gemeinsamen Kreisumfang, an dem Oxidationsbereich (7)
positioniert ist und Strömungsverbindung mit einer äusseren Luftquelle (21) steht,
so dass die Luft von der Luftquelle (21) her in den Oxidationsbereich (7) eingeleitet
werden kann, und wobei der genannte untere Abschnitt (4b) und der Oxidationsbereich
einen Reaktor (22) beschreiben; wobei ein Bereich (9) zum Auslassen des durch den
Reaktor (22) erzeugten Gases unterhalb der Förderelemente (8, 8') angeordnet ist und
eine Bohrung (14) zum Auslassen des Gases nach ausserhalb des inneren Gehäuses (4)
hat;
- Trocknen der Holz-Biomasse im oberen Teil des oberen zylindrischen Abschnittes (4a);
- Karbonisieren der getrockneten Holz-Biomasse im unteren Teil des zylindrischen Abschnittes
(4a); und
- Vergasen der karbonisierten Holz-Biomasse in dem unteren zylindrischen Abschnitt
(4b) des inneren Gehäuses (4);
dadurch gekennzeichnet, dass der Vorgang der Vergasung der Holz-Biomasse die folgenden Phasen enthält:
- Versetzen der gasförmigen Strömung (8g), welche die durch den Reaktor (22) erzeugten
Gase enthält, in eine Drehbewegung um die Längsachse (2a) und gleichzeitig in eine
Vorwärtsbewegung in Richtung eines Bereiches (9) zum Auslassen nach ausserhalb des
inneren Gehäuses (4);
- Abfangen der Strömung (8g) durch ein Diaphragma (13), das quer zu der Längsachse
(2a) ausgerichtet und so geformt ist, dass es zusammen mit den angrenzenden Innenwänden
des unteren Abschnittes (4b) eine Durchlaufleitung mit einem Querschnitt bildet, der
sich sprunghaft verändert, und in welcher die Strömung (8g) durch das Diaphragma (13)
abgefangen und plötzlich zu einer Auslassbohrung (14) abgeleitet wird, wobei die genannte
Abfangphase die Freigabe von festen Partikeln bewirkt, die sich an dem Diaphragma
(13) und an den vertikalen Innenwänden (4) des unteren Abschnittes (4b) ansammeln,
wobei sie diese wenigstens teilweise bedecken und sie mit einer Hitzeisolierung versehen
und verhindern, dass die gasförmige Strömung (8g) in direkten Kontakt mit dem Diaphragma
(13) und den Wänden (4) des unteren Abschnittes (4b) gelangt.
1. Un dispositif pour la gazéification de bois, comprenant une cuve extérieure (2), un
corps intérieur (4), ayant tous deux un axe longitudinal vertical (2a), une tête (5)
et une base (6), ledit corps intérieur ayant une section supérieure cylindrique (4a),
une trémie (4c) et une section inférieure (4b) ; une zone d'oxydation (7) étant située
à l'intérieur de la section inférieure (4b) du corps intérieur (4) à proximité de
la base (6) ; une pluralité d'éléments (8, 8') d'acheminement de fluide étant disposés
au niveau de la zone d'oxydation (7) et en communication de fluide avec une source
d'air externe (21) de sorte que l'air puisse être transféré de la source d'air (21)
à la zone d'oxydation (7), lesdits éléments d'acheminement de fluide (8, 8') étant
orientés de manière à envoyer dans la zone d'oxydation (7) un flux d'air (8f) qui
génère un flux gazeux (8g) contenant les gaz générés, ladite zone inférieure (4b)
et ladite zone d'oxydation définissant un réacteur (22) ; une zone (9) pour l'évacuation
du gaz produit par le réacteur (22) étant située en dessous des éléments d'acheminement
(8, 8') et présentant un trou (14) pour l'évacuation du gaz à l'extérieur du corps
intérieur (4) ; ladite zone d'évacuation (9) comprenant une membrane (13) fixée à
la section inférieure (4b) du corps intérieur (4) transversalement à l'axe longitudinal
(2a) et présentant le trou d'évacuation (14) en question, la membrane (13) délimitant,
avec les parois intérieures de la section inférieure (4b), un conduit de transit pour
le flux gazeux (8g) ayant une section qui varie brusquement, dans lequel le flux gazeux
(8g) est intercepté par la membrane (13) et dévié vers le trou d'évacuation (14),
ladite interception entraînant le flux gazeux (8g) à libérer des particules solides
qui s'accumulent sur la membrane (13) et les parois intérieures verticales adjacentes
de ladite section (4b) et y restent, les isolant au moins partiellement contre la
chaleur et les protégeant d'un contact direct avec le flux gazeux (8g) successif qui
passe à travers le conduit de transit et le trou d'évacuation (14) ; ledit dispositif
étant caractérisé en ce que lesdits éléments d'acheminement comprennent des tubes (8) orientés tangentiellement
à un cercle commun (12) pour faire tourner le flux gazeux (8g) autour de l'axe longitudinal
(2a) et le faire avancer en même temps vers la zone d'évacuation (9) parallèlement
à l'axe longitudinal (2a).
2. Le dispositif selon la revendication 1, caractérisé en ce que lesdits éléments d'acheminement comprennent des lumières (8') réalisées dans les
parois de la section (4b) du corps intérieur (4).
3. Le dispositif selon la revendication 1, caractérisé en ce que lesdits éléments d'acheminement (8, 8') et ledit cercle (12) sont coplanaires.
4. Le dispositif selon la revendication 1, caractérisé en ce que ladite section inférieure (4b) a la forme d'un tube cylindrique et comprend une membrane
(13) supportée par une bague plate (15), cette dernière étant supportée transversalement
à l'axe longitudinal (2a) par les parois intérieures de la section inférieure (4b)
du corps intérieur (4).
5. Le dispositif selon la revendication 1, caractérisé en ce que ledit corps intérieur (4) et ladite cuve extérieure (2) sont montés coaxialement
l'un par rapport à l'autre et séparés de manière à délimiter ensemble un espace (17),
ledit espace (17) étant parcouru par le flux gazeux (8g) qui s'écoule hors du trou
d'évacuation (14).
6. Le dispositif selon la revendication 5, caractérisé en ce que ledit espace (17) est pourvu d'ailettes (19) d'échange de chaleur fixées au corps
intérieur (4).
7. Une méthode pour la gazéification de bois comprenant les phases suivantes :
- introduction d'une biomasse de bois à traiter dans une section cylindrique supérieure
(4a) d'un dispositif (1) qui comprend une cuve extérieure (2), un corps intérieur
(4), ayant tous deux un axe longitudinal vertical (2a), une tête (5) et une base (6),
ledit corps intérieur présentant la section cylindrique supérieure (4a) en question,
une trémie (4c) et une section inférieure (4b) ; une zone d'oxydation (7) étant située
à l'intérieur de la section inférieure (4b) du corps intérieur (4) à proximité de
la base (6) ; une pluralité d'éléments d'acheminement de fluide (8, 8') orientés tangentiellement
à un cercle commun (12) étant disposés au niveau de la zone d'oxydation (7) et en
communication de fluide avec une source d'air externe (21) de sorte que l'air puisse
être transféré de la source d'air (21) à la zone d'oxydation (7), ladite section inférieure
(4b) et ladite zone d'oxydation définissant un réacteur (22) ; une zone (9) pour l'évacuation
du gaz produit par le réacteur (22) étant située en dessous des éléments d'acheminement
(8, 8') susmentionnés et présentant un trou (14) pour l'évacuation du gaz à l'extérieur
du corps intérieur (4) ;
- séchage de la biomasse de bois dans la partie haute de la section cylindrique supérieure
(4a) ;
- carbonisation de la biomasse de bois séchée dans la partie basse de la section cylindrique
(4a) ; et
- gazéification de la biomasse de bois carbonisée au niveau de la section cylindrique
inférieure (4b) du corps intérieur (4) ;
ladite méthode étant
caractérisée en ce que ladite phase de gazéification de la biomasse de bois comprend les phases suivantes
:
- impression au flux gazeux (8g) contenant les gaz générés par le réacteur (22) d'un
mouvement de rotation autour de l'axe longitudinal (2a) et d'un mouvement d'avancement
simultané vers une zone d'évacuation (9) vers l'extérieur du corps intérieur (4) ;
- interception du flux (8g) par une membrane (13) orientée transversalement à l'axe
longitudinal (2a) et conformée de manière à constituer, avec les parois intérieures
adjacentes de la section inférieure (4b), un conduit de transit ayant une section
qui varie brusquement, dans lequel le flux (8g) est intercepté par cette même membrane
(13) et brusquement dévié vers un trou d'évacuation (14), ladite phase d'interception
entraînant la libération de particules solides qui s'accumulent sur la membrane (13)
et les parois intérieures verticales (4) de la section inférieure (4b), les recouvrant
au moins partiellement de manière à les isoler thermiquement et à éviter que le flux
gazeux (8g) ne vienne en contact direct avec la membrane (13) et les parois (4) de
la section inférieure (4b).