EP3498806A1 - System for supplying powder by cyclone formation, method and facility for the gasification of a feedstock of carbon material in a driven flow reactor (dfr) using such a system - Google Patents

Abstract

The invention relates to a system (1) for supplying powder, comprising: - a conveying device (2) with metering, suitable for conveying one or more materials in the form of granules, at a given average flow rate; injection nozzle (6) fed by the conveying device in the form of an envelope delimited by a hollow cylinder extended by a truncated cone comprising an outlet orifice; interior of the casing, the circuit being closed on itself to reinject inside the casing the gas recovered at the outlet thereof, the circuit being adapted to generate a gas cyclone within the casing; the casing at least over a portion of the cylinder height, so that the generated cyclone causes the powder particles down the casing to be gravity discharged through the outlet port.

Description

Technical area

The present invention generally relates to a powder supply system for a part of a downstream installation, such as a reactor in a thermochemical conversion plant.

In particular, it relates to supplies of cohesive powders, such as wood powders, that is to say that they have a natural tendency to spontaneously form arches and vaults.

The invention relates more particularly to an application of food, pressurized containers or not, in powders of carbonaceous material charge, such as biomass, coal or any other type of powders such as a crushed waste ... The Containers to be fed can advantageously be gasification reactors, or other thermochemical conversion systems. In this application, the mass flow rates of solid can be very variable, from a few kilograms up to several tons per hour in industrial conditions.

The invention aims to improve such powder supply systems.

More particularly, the invention finds its application in a process for gasification of biomass and, more generally, carbonaceous material feedstock, in a flow-type gasification reactor driven, to produce fuels or fuels.

Although described with reference to biomass, for conversion into a fuel or a fuel, in particular a liquid fuel, or another synthetic product, the invention can be used for the conversion of other charges of carbonaceous material (coal, pet coke, organic waste ...) or solid recovered fuels (CSR).

State of the art

The term carbonaceous filler means any combustible material consisting of carbon-containing compounds.

It can therefore be biomass, ie any inhomogeneous material of plant origin containing carbon, such as lignocellulosic biomass, forest or agricultural residues (straw), or household waste. All these loads can be dry or wet.

It can also be a fossil fuel, such as coal.

It can also be combustible waste of industrial origin containing carbon, such as plastics. It can thus be solid recovery fuels (CSR), as defined in the EN 15359 standard, ie solid fuels prepared from non-hazardous waste for energy recovery in incineration or co-generation plants. incineration.

It can also be a combination of these different loads.

Current processes under study or at the industrial pilot scale, for thermochemically converting biomass or other charges into liquid or gaseous fuel by chemical synthesis, necessarily include a step of gasification of the carbonaceous feedstock for obtain a synthesis gas containing carbon monoxide (CO) and hydrogen (H2).

The actual gasification step is carried out continuously from the carbonaceous filler of different types and sizes, usually stored at atmospheric pressure.

The gasification of biomass and coal has been known for a long time. In general, it can be defined as a thermochemical transformation of biomass or coal by the action of heat in the presence of gassing agents. It is sought to generate, after the gasification, a gas mixture said synthesis gas which comprises carbon monoxide and hydrogen (CO + H2) among others.

Thus, the gasification processes of the lignocellulosic biomass make it possible to generate a synthesis gas which makes it possible to produce downstream either liquid fuels or other organic products. This gasification takes place in the presence typically of water vapor at 1300-1600 ° C for driven flow reactors (RFE). Conventionally, these processes convert carbon from biomass with a gas at the outlet of the gasifier with an average composition of 20-25% CO, 8-12% CH ₄ , 18-22% CO ₂ and about 38-42% in H ₂ and organic compounds C ₂ to C ₁₆ plus inorganic compounds.

There are various operational or research stage gasification processes that can be grouped as follows: fixed-bed, counter-current, fixed-bed co-current, fluidized-bed gasification and finally, flow-through gasification. .

In a driven flow reactor (RFE), the combustion reaction takes the form of a flame, which implies a very specific mode of injection of biomass.

Thus, it must be introduced into the reactor in the form of atomized powder, particle size typically between 100μm and 1mm, suspended in a carrier gas or carrier gas.

The primary reason for pulverizing the biomass material is the need for sufficiently rapid gasification of the particles that make it up. Indeed, for the powder has time to be completely gasified during its fall in the reactor it must be sufficiently fine.

The atomized jet is then brought into contact with the oxidizing agent, a mixture of oxygen and water vapor. In order to obtain good combustion, the mixture with the oxidant must be done quickly and in the most homogeneous manner possible. However, the combustion of a part of the material is one option among others to bring the necessary heat to the gasification process. One can very well have a burner supplied with oxygen and / or methane if one does not wish to burn the material to gasify.

The biomass is injected into the entrained flow reactor (RFE) preferably via a small diameter tube, typically from 1 cm to a few centimeters, which makes it possible to limit the rise of heat and gas in the biomass feed system. .

The biomass powder feed of a driven flow gasification reactor and, more generally, a powder feed of various and varied containers, must be made with a conveying device with powder dosing, that is to say which makes it possible to convey and control the quantity of powder, and downstream with a device for the injection of powders into a container, continuously or discontinuously.

Among the conveyor devices with widespread metering, there may be mentioned devices with storage hopper connected downstream worm, rotary locks or pressurizing airlock, commonly called "lock hoppers" in English.

For example, the patent application WO2012 / 152742A1 discloses a rotary lock for metering a powder which feeds directly from the lock a kneader.

The patent US9227790B2 relates to a gasification plant for biomass or coal in which the powder is conveyed by a helical worm conveyor.

There are also pressurization airlock, whose more or less important volume defines the fineness of the dosage. One advantage of locks and pressurizing airlocks is that they also have a sealing effect against possible pressure fluctuations upstream and downstream.

The main disadvantage of using a hopper for storing a cohesive powder is that its flow is done by forming a kind of chimney, or even arches that will limit the flow of powder out of the hopper, even prevent it.

The major disadvantage of metering screws, locks and lock-hoppers is the highly discontinuous nature of the powder flow generated. In addition, the compaction of the powder in a worm can lead to blocking of the latter.

In order to overcome these disadvantages, several solutions exist.

First of all, it is known to use vibratory systems to ensure the flow of the powder within the storage hopper.

Furthermore, it is usual to replace a worm by a pneumatic conveyor, which is expensive and does not guarantee the absence of compaction of the conveyed powder.

Another solution usually consists in arranging a large number of metering devices, either in fluidic series with a volume, therefore a decreasing flow rate, for example rotating locks with an increasing number of buckets of decreasing size going towards the point. injection, or in parallel, with an alternating dosage of several devices. In addition to the investment and management constraints of alternate operation, this solution has the disadvantage of generating a significant footprint. On the other hand, for cohesive powders, problems of plugging by compaction of the powder in the cups occur frequently.

In the field of conveying and gasification of coal powder, the solution consists in controlling the solid flow rate by an additional flow of gas: see publications [1], [2]. A conveying with gas, also referred to as "aerated injection", has the advantage of not generating additional space. On the other hand, it generates a highly diluted phase flow, which may not be compatible with many downstream processes.

This is particularly problematic in a thermochemical conversion plant in which the gas does not participate in the reaction and thereby decreases the efficiency. This can be particularly disadvantageous at high pressure, because of the increased density of the gas, which increases the ratios between mass flow rate of the gas and solid mass flow rate. For example, using a conveying gas by diluting the powder particles in a biomass gasification plant would require using a portion of the energy of the gasification reaction to heat the initially cold gas, which would have the effect of undesirable to decrease the overall yield of the reaction.

With regard to the injection devices, mention may be made of the old literature and provided on the discharge silos. These "funnel" type elements in the form of a truncated cone make it possible to inject a granular material into a smaller container. On the other hand, these funnels, usually called injection cones, do not have the function of dosing the granular material and provide just a discharge by gravity. Thus, in these known injection devices, the value of the flow rate is not adjustable.

The major disadvantage of the injection cones is that the powder can cause clogging within them, due to the irregular arrival of powder in the form of packets and not constant flow, these packages can also have a certain cohesion due to compaction in the upstream conveying device, such as a worm. One solution is to add a vibratory system to the injection cone, which as for the injection hopper is expensive and does not guarantee the absence of clogging.

It is also possible to find different injection devices aerated by a gas, for fluidizing the powder, which are described in detail in the publication [2]. Thus, as for conveyors with dosing, these injection devices find an application in the diluted phase with a solid volume fraction reached which is a few%.

Another disadvantage of this type of aerated injection is that the dosing and powder injection functions are not separated since it is the two-phase mixture and therefore the gas flow rate that largely determines the solid flow rate.

Finally, for very cohesive powders and / or not easily fluidizable, this type of injection is complex to achieve and very dependent on the nature of the powders, as explained by the publication [2].

If in the prior art, there are dense phase powder supply systems that combine a conveying device with powder metering and an injection device, the disadvantages specific to each device remain.

Thus, all the solutions according to the state of the art increase the cost and the complexity of a powder supply system and do not systematically guarantee its proper functioning according to the variable powder flow properties as a function of the type of material (x) forming the powder.

There is therefore a general need to improve the powder supply systems of downstream industrial equipment, in particular to avoid the problems of chimney flow with arches, compaction of the powder which can lead to capping all or part of the systems with a fine, precise and stable dosing, without compromising the cost of systems realization.

There is a particular need to improve the powder supply systems of a feedstock of carbonaceous material, preferably lignocellulosic biomass, of a continuous plant with a driven flow type gasification reactor, with a view to to produce fuels or fuels, in particular to ensure reliable operation and increase the profitability of the overall installation.

The object of the invention is to at least partially meet this (these) need (s).

Presentation of the invention

• un dispositif de convoyage avec dosage, adapté pour convoyer un ou des matériaux sous la forme de granulés, selon un débit moyen donné;
• un dispositif d'injection alimenté en poudre par le dispositif de convoyage, le dispositif d'injection étant sous la forme d'une enveloppe délimitée par un cylindre creux prolongé par un tronc de cône comprenant un orifice de sortie;
• un circuit de circulation de gaz à l'intérieur de l'enveloppe, le circuit de gaz étant fermé sur lui-même pour réinjecter à l'intérieur de l'enveloppe le gaz récupéré en sortie de celle-ci, le circuit étant adapté pour générer un cyclone de gaz à l'intérieur de l'enveloppe au moins sur une partie de la hauteur de cylindre, de sorte que le cyclone généré entraîne les particules de poudre vers le bas de l'enveloppe afin qu'elles soient évacuées par gravité par l'orifice de sortie.

To do this, the subject of the invention is a powder supply system, comprising:

• a metered conveying device adapted to convey one or more materials in the form of granules, at a given average flow rate;
• an injection device fed with powder by the conveying device, the injection device being in the form of an envelope delimited by a hollow cylinder extended by a truncated cone comprising an outlet orifice;
• a gas circulation circuit inside the casing, the gas circuit being closed on itself to reinject inside the casing the gas recovered at the outlet thereof, the circuit being adapted to generate a gas cyclone inside of the casing at least over a portion of the cylinder height, so that the generated cyclone causes the powder particles down the casing to be gravity discharged through the outlet port.

According to an alternative embodiment, the gas circuit comprises a gas inlet duct opening in a tangential direction in the upper part of the cylinder of the casing.

The inlet duct may be of rectangular section.

According to another embodiment, the gas circuit comprises a gas outlet duct opening on the top in the axis of the cylinder of the casing.

Preferably, the outlet duct is a cylinder mounted inside and coaxially with the cylinder of the casing.

According to an advantageous variant embodiment, the metering conveying device comprises a worm whose output opens into the cylinder of the envelope.

1. a/ convoyage avec dosage d'une poudre;
2. b/ génération d'un cyclone de gaz au sein d'une enveloppe d'injection, de sorte à entraîner la poudre convoyée, vers le bas de l'enveloppe,
3. c/ injection par gravité de la poudre évacuée par gravité depuis l'enveloppe, dans un réacteur de gazéification (4) de type à flux entrainé (RFE), de préférence à des températures comprises entre 1300 et 1600°C.

The invention also relates, in another aspect, to a process for gasification of a carbonaceous material charge into a synthesis gas for producing a fuel or a fuel, in particular a liquid fuel, or another product. synthesis, comprising the following steps:

1. a / conveying with dosing of a powder;
2. b / generating a gas cyclone within an injection casing, so as to cause the conveyed powder, towards the bottom of the casing,
3. c / gravity injection of the powder discharged by gravity from the casing into a gasification reactor (4) of the trapped flow type (RFE), preferably at temperatures between 1300 and 1600 ° C.

Advantageously, the flow rate of gas forming the cyclone is of the order of 3.5 l / s, for a conveyed powder particle rate of between 0 and 50 kg / h.

Advantageously, the size of the particles of powder conveyed is between 10 .mu.m and 1 mm.

• un système d'alimentation décrit précédemment,
• un réacteur de gazéification de type à flux entraîné (RFE), agencé en dessous du dispositif d'injection du système d'alimentation.

Finally, the subject of the invention is a carbonaceous material charge gasification installation intended to continuously implement the process described above, comprising:

• a feeding system described previously,
• a driven flow type gasification reactor (RFE) arranged below the fuel system injection device.

Thus, the invention essentially consists in creating a fluidization of the powder by generating a cyclone of entrainment gas of the powder particles in the volume of an injection envelope.

The circulation circuit is configured to circulate the gas in closed circuit by recovering the gas having circulated on the top of the envelope to reinject it tangentially to the cylinder of the envelope in its upper part.

The rotational speeds of the gas within the cyclone are sufficiently high to entrain the powder particles that are discharged through the outlet of the cone by gravity, that is to say by their own weight.

Surprisingly, although many studies have addressed the problem of conveying and injecting a carbonaceous charge in the form of powder, it seems that nobody has thought to implement a fluidization of the powder by gas cyclone.

• suppression des problèmes de blocage, arches, bouchon et autres que l'on rencontre dans les systèmes d'alimentation en poudre selon l'état de l'art;
• du fait de la circulation du gaz, fluidisation de l'injection de poudre, sans risque d'interférence avec une installation en aval, notamment un réacteur RFE que l'on souhaite alimenter en poudre;
• simplicité de mise en oeuvre et dimensionnement d'un cyclone de gaz dans l'enveloppe d'injection;
• faible puissance de fonctionnement nécessitée par la fluidisation avec cyclone;
• possibilité d'utiliser une plus grande variété de matière carbonée du fait qu'on peut envisager de mettre en oeuvre la fluidisation par cyclone pour des poudres qui ne sont pas considérées habituellement comme fluidisables, notamment pour un procédé industriel aval de conversion thermochimique, en particulier pour la gazéification. En effet, les vitesses de rotation du cyclone peut être très élevées pour renforcer la dispersion de tout type de poudre qui est introduite dans l'enveloppe ;
• possibilité d'utiliser des poudres très fines de l'ordre de la dizaine de microns car on peut aisément régler le diamètre de coupure du cyclone à créer qui est fonction de sa vitesse de rotation.

The invention which has just been described has numerous advantages among which we can mention:

• removal of blockage problems, arches, plugs and others found in powder supply systems according to the state of the art;
• due to the circulation of the gas, fluidization of the powder injection, without risk of interference with a downstream installation, in particular an RFE reactor that it is desired to supply powder;
• simplicity of implementation and design of a gas cyclone in the injection casing;
• low operating power required by cyclone fluidization;
• possibility of using a greater variety of carbonaceous material because it is possible to envisage using cyclone fluidization for powders which are not usually considered as fluidizable, especially for a downstream industrial process of thermochemical conversion, in particular for gasification. Indeed, the rotation speeds of the cyclone can be very high to enhance the dispersion of any type of powder that is introduced into the envelope;
• possibility of using very fine powders of the order of tens of microns because it is easy to adjust the cut-off diameter of the cyclone to create which is a function of its rotational speed.

detailed description

• la figure 1 est une vue schématique d'une partie d'une installation de conversion thermochimique en continu d'une charge de matière carbonée selon l'état de l'art mettant en oeuvre un système d'alimentation en poudre de la charge, avant son injection dans un réacteur de gazéification de type à flux entraîné;
• les figures 2A à 2F sont des vues schématiques en coupe de détail de différentes solutions selon l'état de l'art de fluidisation de l'écoulement par injection de gaz continue ou intermittente au travers de la paroi d'un cône ou d'une trémie d'injection de poudre d'une charge carbonée ;
• la figure 3 est une vue schématique en perspective d'un système d'alimentation en poudre de charge carbonée selon l'invention ;
• la figure 4 reprend en vue de coupe longitudinale le système selon la figure 3 avec les dimensions symbolisées des différents éléments ;
• la figure 5 est une vue issue d'une simulation numérique, qui montre les trajectoires du gaz dans la périphérie extérieure du cyclone formé selon l'invention ;
• la figure 6 est une vue issue d'une simulation numérique, qui montre les trajectoires des particules d'une poudre de biomasse, suivie à l'intérieur du cyclone formé selon l'invention.

Other advantages and features of the invention will emerge more clearly from a reading of the detailed description of the invention, given by way of illustration and without limitation with reference to the following figures among which:

• the figure 1 is a schematic view of a portion of a continuous thermochemical conversion plant of a carbonaceous material feedstock according to the state of the art using a powder feed system of the feed, before its injection into a flow-type gasification reactor;
• the Figures 2A to 2F are diagrammatic views in detail section of different solutions according to the state of the art of fluidization of the flow by continuous or intermittent gas injection through the wall of a cone or an injection hopper powder of a carbonaceous charge;
• the figure 3 is a schematic perspective view of a carbonaceous charge powder feed system according to the invention;
• the figure 4 resumes in longitudinal section view the system according to the figure 3 with the symbolized dimensions of the different elements;
• the figure 5 is a view from a numerical simulation, which shows the trajectories of the gas in the outer periphery of the cyclone formed according to the invention;
• the figure 6 is a view from a numerical simulation, which shows the particle trajectories of a biomass powder, followed inside the cyclone formed according to the invention.

In the description which follows the terms "inlet", "outlet" "upstream", "downstream", are used by reference with the direction of transfer of the carbonaceous material charge in a powder supply system according to the invention .

It is specified that if, figure 1 , the storage hopper is shown above the gasification reactor with a worm horizontally, this is a schematic representation and in practice, the hopper rests on the ground next to the reactor and the worm is arranged obliquely and conveys the carbonaceous feed powder from bottom to top.

As illustrated in figure 1 , a continuous installation according to the state of the art implements the process of a gasification of a carbonaceous charge by supplying the charge under a powder by a system 1 adapted, in a reactor 4 of type to driven flow.

Thus, the gasification reactor 4 entrained flow (EFR or RFE, English acronym for "entrained flow reactor") preferably operating at temperatures typically between 1300 to 1600 ° C and a pressure between 30 and 50 bars is fed with continuous by the load by a conveying device with dosage 2.

More specifically, the carbonaceous material feed is prepared by grinding to be put into the form of a powder P which is stored in a suitable storage hopper 20.

The continuous feed with metering is carried out by means of at least one worm 21, for example as described in the patent application. WO 2005/092749 .

Below the end of the worm 21 is arranged an injection cone 3 which makes it possible to inject the carbonaceous feed powder directly into the reactor 4 situated below said cone 3.

In this type of installation 1 according to the state of the art, it has been observed upstream of the gasification reactor 4, several problems related to the use of the powder to feed the reactor.

First of all, the powder can flow by forming a chimney in the storage hopper 20, possibly with the formation of arches which will limit the flow of powder out of the hopper 20 or even prevent it.

In addition, the powder may tend to compact in the worm 21, which can lead to the blocking of the latter.

Finally, the irregular arrival of the powder in the form of packets and not constant flow in the injection cone 3 can lead to clogging, the packets may also have some cohesion due to compaction in the worm 21 .

The Figures 2A to 2F show different variants of pressurized gas injection devices for fluidifying the powder which feeds a cone 3 or injection hopper.

• un cône 3 percé d'une pluralité de trous d'injection 30 de gaz pour former un cône poreux 5.1 (figure 2A) ;
• un boitier d'aération 5.2 agencé dans une portion de la paroi du cône 3 (figure 2B);
• un élément formant un pommeau d'aération 5.3, monté à l'intérieur de la paroi du cône 3 (figure 2C) ;
• une buse d'aération 5.4, montée à l'intérieur de la paroi du cône 3 (figure 2D) ;
• une buse d'aération 5.5 qui peut en outre vibrer, montée à l'intérieur de la paroi du cône 3 (figure 2E) ;
• un réservoir de de décharge 5.6 monté à l'extérieur de la paroi du cône 3 et avec un tuyau d'injection 5.7 relié au réservoir qui débouche à l'intérieur du cône 3 (figure 2F).

A gas injection device can therefore consist of:

• a cone 3 pierced with a plurality of gas injection holes 30 to form a porous cone 5.1 ( Figure 2A );
• a ventilation box 5.2 arranged in a portion of the wall of the cone 3 ( Figure 2B );
• an element forming a ventilation knob 5.3, mounted inside the wall of the cone 3 ( Figure 2C );
• a ventilation nozzle 5.4, mounted inside the wall of the cone 3 ( 2D figure );
• a ventilation nozzle 5.5 which can also vibrate, mounted inside the wall of the cone 3 ( figure 2E );
• a discharge tank 5.6 mounted outside the wall of the cone 3 and with an injection pipe 5.7 connected to the tank which opens into the cone 3 ( figure 2F ).

These gas injection devices have several major disadvantages.

Firstly, they are applicable only for so-called fluidizable powders, since in the end their operation is quite close to fluidized bed techniques.

With more cohesive powders, like most biomass powders, the fluidisation is not done, and in general we observe a phenomenon called "firing" where the gas forms tunnels through which it can escape.

The gas injection also has the major drawbacks of creating overpressures in the powder injection device and generating a gas stream which is injected additionally into the downstream thermochemical reactor, which is not necessarily desirable.

Vibratory devices do not really provide more effective solutions.

Therefore, the inventor has thought to generate a cyclone in the volume of a casing of a powder injection device by performing a gas flow within it. The circulation of the gas is advantageously provided to recover the injected gas and reinject it into the envelope volume, so that it does not escape through the outlet orifice of the powder at the bottom of the envelope.

Thus, according to the invention, as illustrated in figure 3 the powder supply system first comprises a powder conveying device 21 which may be customary for supplying the powder inside a powder injection device in the form of an envelope 6.

This casing 6 of longitudinal axis X is constituted by a hollow cylinder 60 extended downwards by a truncated cone 61 comprising an outlet orifice 62 or discharge of the powder P.

The powder conveying device 21 may comprise a worm whose output opens into the cylinder 60 of the envelope 6.

A gas circulation circuit 7 makes it possible to inject gas into the upper part of the cylinder 6.

More specifically, the gas is injected tangentially to the cylinder 60 through an inlet duct 70, circulates internally over at least the height of the cylinder 60 forming a cyclone and then exits through the outlet duct 71.

The outlet duct 71 is formed by a coaxial hollow cylinder and mounted partly inside the cylinder 60 of the casing 6.

The flow of gas proceeds in a loop since the circuit 7 is provided with a return of gas between the outlet duct 71 and the inlet duct 70. Thus, the gas is reinjected into the casing 6.

With this configuration, the powder particles can be driven by the rotating gas according to the generated cyclone. Naturally, care is taken to generate gas rotation speeds that are high enough to entrain the P powder particles.

At the outlet, the powder P is evacuated under the effect of its own weight by the outlet orifice 62.

The figure 4 illustrates the shapes and dimensions to be given to the various components of the powder supply 21, the casing and the gas circuit 7, to effectively generate a cyclone.

• la taille de particules de poudre de biomasse est comprise entre 0,2 mm et 1 mm avec une taille moyenne de 0,5 mm et une forme possible de particules qui ne soit pas sphérique ;
• la densité des particules est de l'ordre de 700 kg/m³ ;
• le débit de biomasse est de 50kg/h et fourni par une vis sans fin 21 ;
• le gaz injecté et recirculant dans le circuit 7 est de l'azote.

As an indication, an example of sizing is given below for the following conditions:

• the particle size of biomass powder is between 0.2 mm and 1 mm with an average size of 0.5 mm and a possible form of particles that is not spherical;
• the density of the particles is of the order of 700 kg / m ³ ;
• the biomass flow rate is 50 kg / h and provided by a worm 21;
• the gas injected and recirculating in the circuit 7 is nitrogen.

It is specified here that the inventor has respected the geometric proportions given in the publication [3], on page 28 of Chapter 17, for gas cleaners.

• diamètre extérieur D₂₁ de la vis sans fin 21 égal à 60 mm;
• cylindre 60 de hauteur H₆₀ égale à 160 mm, de diamètre intérieur D₆₁ correspondant à celui d'entrée du cône égal à 80mm;
• cône 61 de hauteur H₆₁ égale à 160 mm ;
• diamètre intérieur D₆₂ de l'orifice de sortie 62 de la poudre égal à 20 mm;
• conduit d'entrée du gaz 70, de section rectangulaire avec une hauteur H₇₀ égale à 40 mm et une largeur L₇₀ égale à environ 18mm ;
• conduit de sortie du gaz 71, sous la forme d'un cylindre de diamètre intérieur D₇₁ égal à 40 mm emmanché coaxial et à l'intérieur du cylindre 60 sur une hauteur H₇₁ de l'ordre de 50 mm.

With the symbols used in figure 4 , the shapes and dimensions are as follows:

• outer diameter D ₂₁ of the worm 21 equal to 60 mm;
• cylinder 60 of height H ₆₀ equal to 160 mm, of internal diameter D ₆₁ corresponding to that of entry of the cone equal to 80 mm;
• cone 61 of height H ₆₁ equal to 160 mm;
• internal diameter D ₆₂ of the outlet orifice 62 of the powder equal to 20 mm;
• gas inlet duct 70 of rectangular section with a height H ₇₀ equal to 40 mm and a width L ₇₀ equal to about 18 mm;
• gas outlet duct 71, in the form of a cylinder of internal diameter D ₇₁ equal to 40 mm coaxially fitted and inside the cylinder 60 on a height H ₇₁ of the order of 50 mm.

In order to validate the creation of a cyclone with such a device, the inventor has carried out a numerical simulation using the calculation code marketed under the name FLUENT.

To obtain the creation of the cyclone, it is necessary to apply a pressure difference of about 100 Pa in the recirculation loop 7 of the gas. A flow of gas circulating inside the envelope 6 of the order of 3.5 * 10 ^-3 m ³ / s is then obtained. The power required for generating the cyclone is therefore of the order of 0.35 W.

The rotational speed of the cyclone gas in the hollow cylinder 60 is of the order of 5 m / s.

The figure 5 shows the trajectories of the gas G in the outer periphery of the cyclone.

The figure 6 shows the trajectory of the P biomass powder particles. It is verified that the particles are taken in the swirling motion of the cyclone, ie driven by the cyclone, towards the bottom of the cone 61. These particles are then evacuated by 62. No particles reach the center of the cyclone because of the cutting diameter of the cyclone much lower than the minimum diameter of the injected particles.

For a gasification application of lignocellulosic biomass or solid recovery fuels (CSR), the particles of the powder P which can feed the cyclone can be very thin and typically have a size of between 10 microns and 1 mm.

Although described with reference only to biomass, the conversion plant into a fuel or a fuel, in particular a liquid fuel, or another synthetic product, the invention may be used for the conversion of other feeds of carbonaceous material. (coal, pet coke, organic waste ...) or solid recovered fuels (CSR).

Other variants and improvements may be provided without departing from the scope of the invention.

The invention is not limited to the examples which have just been described; it is possible in particular to combine with one another characteristics of the illustrated examples within non-illustrated variants.

References Cited

• [1]: " Pneumatic convection of solids ", KLINGZING, GE, RIZK, F., MARCUS, R. & LEUNG, LS, third edition, 2010 .
• [2]: " Pneumatic conveying design guide ", MILLS, D, Elsevier, 2006 .
• [3]: Perry's Chemical Engineers Handbook, Eighth Editi we

Claims (10)

Powder feeding system (1) (1), comprising: - A metering conveyor (2, 21), adapted to convey one or more materials in the form of granules, at a given average flow rate; - an injection device (6) fed with powder by the conveying device, the injection device being in the form of an envelope delimited by a hollow cylinder (60) extended by a truncated cone (61) comprising a outlet port (62); a circuit (7) for circulating gas (G) inside the casing, the gas circuit being closed on itself to reinject inside the casing the gas recovered at the outlet of the casing; ci, the circuit being adapted to generate a gas cyclone inside the casing at least over a portion of the cylinder height, so that the generated cyclone causes the powder particles towards the bottom of the casing to they are evacuated by gravity through the outlet. System (1) for supply according to claim 1, the gas circuit comprising an inlet duct (70) of the gas opening in a tangential direction in the upper part of the cylinder of the casing. System (1) supply according to claim 2, the inlet duct being of rectangular section. System (1) supply according to one of the preceding claims, the gas circuit comprising an outlet duct (71) of the gas opening on top in the axis of the cylinder of the casing. A feed system (1) according to claim 4, the outlet conduit being a cylinder mounted therein and coaxially with the cylinder of the housing. System (1) supply according to one of the preceding claims, the metering conveying device comprising a worm (21), the output opens into the cylinder of the envelope. A method of gasifying a carbonaceous material feedstock to a synthesis gas for producing a fuel or a fuel, such as a liquid fuel, or other synthetic product, comprising the steps of: a / conveying with dosing of a powder; b / generating a gas cyclone within an injection casing, so as to drive the conveyed powder down the casing, the gas generating the cyclone circulating in a circulation circuit closed on it; even to reinject inside the envelope the gas recovered at the exit of this envelope, c / gravity injection of the powder discharged by gravity from the casing into a gasification reactor (4) of the trapped flow type (RFE), preferably at temperatures between 1300 and 1600 ° C. Gasification process according to claim 7, the flow rate of gas forming the cyclone is of the order of 3.5 l / s, for a conveyed powder particle rate of between 0 and 50 kg / h. Gasification process according to claim 7 or 8, the size of the particles of powder conveyed being between 10 .mu.m and 1mm. Carbonaceous material charge gasification plant for continuously operating the method according to one of claims 7 to 9, comprising: - a power system (1) according to any one of claims 1 to 6, - A gasification reactor (4) of the driven flow type (RFE), arranged below the injection device of the feed system.

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