WO2024008756A1

WO2024008756A1 - Integrated salt separator, comprising a hollow worm and balls forming salts precipitation and discharge supports, associated biomass gasification facility

Info

Publication number: WO2024008756A1
Application number: PCT/EP2023/068462
Authority: WO
Inventors: Gilles Ratel; Thierry Chataing; Olivier Delattre; Hary DEMEY CEDENO
Original assignee: Commissariat A L'energie Atomique Et Aux Energies Alternatives
Priority date: 2022-07-04
Filing date: 2023-07-04
Publication date: 2024-01-11
Also published as: FR3137378A1

Abstract

The invention relates to a separator for salts contained in a solution which is brought with moving balls by means of a worm, under supercritical conditions. Moving of the heated balls brings them into the hollow cylinder of the worm, where their temperature above the salt precipitation temperature allows the salts to settle on the surface of the balls. Movement of the heated balls in a loop firstly allows the solution for conversion to be heated to a temperature ensuring the precipitation of the salts on the balls and then allows the solution for conversion to be separated into a salt-depleted stream which is discharged from the separator and directed to a conversion reactor, in particular a gasification reactor, and into a stream loaded with dissolved salts to be extracted in the form of a brine discharged by preferably gravity emptying through a grid.

Description

Title: Integrated salt separator, comprising a hollow endless screw and balls forming salt precipitation and evacuation supports, Associated biomass gasification installation.

Technical area

The present invention generally relates to salt separators and more particularly those intended to be used in an installation for the thermochemical conversion of a carbonaceous material feed, in particular under a supercritical fluid, for the production of a gas mixture.

By “load of carbonaceous material”, we mean here and in the context of the invention any material containing a quantity of carbon, in particular any carbonaceous material from residues.

It can therefore be biomass, that is to say any inhomogeneous material of plant origin containing carbon, such as lignocellulosic biomass, forestry or agricultural residues (straw), which can be almost dry or soaked in water such as household waste or waste resulting from water treatment such as sewage treatment plant sludge.

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

It can also be combustible waste of industrial origin, in particular from the food industry, containing carbon, such as plastics or used tires, used oils, organic solvents.

It can also be a combination of biomass and fossil fuel.

By “supercritical fluid”, we mean here and in the context of the invention, the usual meaning, namely a pressure and a temperature beyond which the fluid is in a supercritical state. Its behavior becomes intermediate between the liquid state and the gaseous state: its density is that of a liquid, but its low viscosity is similar to that of a gas.

Thus, by “supercritical water” is meant the usual meaning, that is to say water at temperatures above 374°C under a pressure above 22.1 MPa.

Although described with reference to a preferred application of gasification of a charge of carbonaceous material under supercritical water, a salt separator according to the invention can be implemented in numerous applications, and particularly in the industrial fields of agri-food, chemistry, energy, including the oil sector and the transport sector, ... for which a separation of salts an aqueous fluid mixture is required.

Generally speaking, a salt separator according to the invention is suitable for the separation of salts initially present in aqueous solutions with or without organic matter.

More specifically, a salt separator according to the invention is advantageously used in a thermochemical conversion installation of wet carbon resources, such as supercritical water gasification.

Prior art

Many existing processes make it possible to thermochemically convert a carbon load into liquid (biofuels, biochar), solid (pellets), and gaseous (biogas, methane, syngas, hydrogen) fuels.

Among these, the gasification of biomass and coal has been known for a long time. Generally speaking, it can be defined as a thermochemical transformation of biomass or coal by the action of heat in the presence of gasifying agents. We seek to generate, at the end of gasification, a mixture of gases.

Thus, lignocellulosic biomass gasification processes make it possible to generate a gas rich in methane or hydrogen.

More specifically, hydrothermal gasification, also called supercritical water gasification, is a thermochemical process making it possible to produce renewable gas from moist organic matter, comprising a dry matter content typically between 5 and 20% by mass, for example waste from the food industry, industrial effluents such as black liquor, non-spreadable methanization digestates and sludge from sewage treatment plants. By operating at high temperature and pressure, the process generates a synthesis gas with a high energy content, composed of a mixture rich in methane, hydrogen, carbon dioxide (syngas) and other light hydrocarbons.

By exploiting the properties of water in supercritical conditions, i.e. at a temperature above 374°C and at a pressure above 221 bar, the medium becomes very reactive, which which allows hydrothermal gasification to achieve excellent conversion rates of carbon from biomass into gas, around 70-90%, while separating inorganic elements (salts), potentially allowing their valorization into nutrients, in particular elements nitrogen, phosphorus, and potassium.

In general, the separation and recovery of inorganic constituents present in the feed stream of reactors that implement thermochemical processes are crucial, because these constituents can lead to blockage of the installation, fouling and poisoning of the gasification catalyst. In addition, salt recovery offers the possibility of producing fertilizer as a valuable by-product (nutrients), as explained above.

This problem of separation of salts is even more significant in the case of gasification in supercritical water: the evolution of the dielectric constant and the ionic product of the water in the supercritical state lead to the precipitation of the salts contained in the resource. Indeed, near the critical point, the properties of water change with a significant drop in the density and dielectric constant of water, among others. Under these conditions, the atoms of inorganic components that could be dissolved/transported in water below the critical point are no longer dissolved/transported in water. Some of these salts can modify the physical properties of the water and form a dense phase that flows down the reactor, but most precipitate and then agglomerate on hot surfaces and cause reactor blockages and induce intermittent shutdowns. of the related installation. Managing precipitation and the location of this precipitation is a key element for the development of hydrothermal gasification.

Numerous articles in the literature show that the separation of salts in a thermochemical conversion process is of major importance for the real efficiency of the overall process and for the lifespan of the related installation. However, the disadvantage of the salt separators known up to now is that the separation of the salt is still not satisfactory or, although satisfactory, requires too high thermal or mechanical energy inputs or that the salts are associated with a significant portion of organic matter. Additionally, clogging and deposits are a major problem in such salt separators. More particularly, various scientific articles focus on the dynamics of salt precipitation under supercritical hydrogenation conditions, which makes it possible to separate salts initially present from an aqueous solution containing organic matter.

Figure 1 reproduces a salt separator as disclosed in publication [1], as it was envisaged for the gasification of biomass with supercritical water. This separator 1 comprises, as a biomass injection device, a cylindrical tube 10 with an injection orifice 11 through which the biomass is injected, and an outlet orifice 12 through which the biomass is discharged into a chamber interior C delimited by a double-walled enclosure 2 20, 21 of which the exterior 21, thermally insulating, integrates heating elements 22 which thus heats the chamber C and the injection tube 10.

When the wet biomass is introduced into tube 10, it is gradually brought to a temperature of approximately 450°C: precipitation occurs almost instantly as soon as the temperature reached causes a reduction in the solubility of the salts, leading to separation. wet biomass in various phases, in particular solids in a separation zone S within the chamber C.

In the configuration installed vertically of the separator, the biomass se/water/salts and other solids mixture, this separation zone S generates a gravity separation into a brine very loaded with salts and a solution depleted in salts. A resolubilization zone R, immediately below the separation zone S allows the resolubilization of the salts which are therefore evacuated by gravity in the form of brine through the outlet orifice 23 drilled in the bottom 24 of the separator, and this without mixing with the part of the effluents which rises in the chamber C to be evacuated through the outlet orifice 25 towards a gasification reactor, not shown.

Such gravity separators are also described in publications [2] and [3]: they are used for inorganic fluids and salt deposits for hydrothermal gasification. For the same application, there are also cyclonic separators.

Overall, a gravity separator operates satisfactorily when the phases involved prove to be denser than the carrier medium and according to a grain size distribution allowing gravity separation and brine-type behavior, salts which are referred to as brine-type I in this case. However, in certain cases, salts precipitate in particles so small (micro or nanoparticles) that they do not sediment.

In other cases, gravity separation is not easy, as specified in the publication [3]. Thus, the passage of wet carbonaceous material in subcritical conditions to supercritical conditions can be accompanied by the appearance of very sticky solid phases, in the form of salts that we qualify as type II. These type II salts can accumulate on the internal walls of the interior chamber of the separator and, if necessary, clog the injection tube 10 of the separator as shown in Figure 1.

To avoid such harmful accumulation of salts II, one could consider applying known solutions, implemented in scraped surface type heat exchangers. Such exchangers are used in particular in clogging processes, that is to say when the walls of the exchangers can be the site of clogging phenomena of the walls involved in heat transfers, i.e. with the deposition of undesirable materials.

For example, the scrapers used can be rotary, for example of the endless screw or blade type, or even oscillating of the piston type, for example with plates, annular or not. The actuation of the scraper, rotary or oscillating piston type, is generally operated by an electric motor.

Scrapers for heat exchangers have in particular been considered for supercritical oxidation reactors, as described in patents US 5,100,560A, US6,054,057 A and US5, 461,648 A.

Patent application US2012/214977 describes a scraper for ultrafiltration applications. Specific scrapers have also been considered for viscous fluids: https://www.hrsasia.co.in/heat-exchanger-specialists/scraped-surface-heat-exchanger/.

In the field of organic fluids, other cleaning solutions have already been considered, including:

- the vibration of parts by pressure pulsation, as described in application US2008/0073063A1,

- chemical treatments, such as that of patent application CA 2119056. All of these solutions are not suitable for the problem of accumulation of type II salts on the walls, which can also possibly occur on the scrapers themselves.

There is therefore a need to find a solution which makes it possible to better control the elimination of salts, in particular type II, present in a solution, in particular a solution intended to undergo a thermochemical conversion treatment such as wet biomass intended for be gasified.

The aim of the invention is to respond at least in part to this need.

Presentation of the invention

To do this, the invention relates to a salt separator for separating salts from a carbonaceous material containing them, the salt separator comprising:

- an enclosure delimiting an interior chamber and comprising: a cover pierced with a first injection orifice through which a carbonaceous material containing one or more salts is intended to be injected, at least one side wall pierced with a second orifice injection by which water is intended to be injected, at least part of the height of the side wall being adapted to be heated, the side wall and/or the cover being pierced with at least one first orifice outlet through which the effluents of carbonaceous material devoid of precipitated salts are intended to be evacuated, a bottom, the side wall and/or the bottom being pierced with at least a second outlet orifice through which the precipitated salts are intended to be discharged in the form of brine;

- a grid arranged in the interior chamber of the enclosure;

- balls contained in the interior chamber of the enclosure and sized not to pass through the grid;

- a hollow cylinder opening at its two ends, the cylinder comprising, on its outer periphery, a helical groove forming an endless screw, the endless screw being mounted in rotation inside the interior chamber of the enclosure so that the first injection orifice opens inside the hollow cylinder, the lower end of the hollow cylinder is arranged above the grid and the upper end of the hollow cylinder is arranged at a distance from the cover sufficient to allow the balls to pass from the interior chamber of the enclosure towards the interior of the hollow cylinder.

The separator is advantageously configured so that in operation, when carbonaceous material is injected through the first injection port into the interior of the hollow cylinder and water is injected into the interior chamber through the second injection port , at a pressure above its critical pressure but at a temperature below its critical temperature, the rotation of the endless screw causes the balls to move in a loop comprising:

- a heating zone, outside the endless screw, along the side wall of the enclosure in which the water and the balls are heated by it to a temperature greater than or equal to the critical temperature water and precipitation of salts,

- downstream of the heating zone, a precipitation zone inside the hollow cylinder, in which on contact with the hot balls, the salts contained in the carbonaceous material precipitate,

- downstream of the precipitation zone, a resolubilization zone, between the lower end of the hollow cylinder and the grid in which the salts precipitated on the balls are dissolved then evacuated through the grid, with where appropriate the salts in the form particles present in the carbonaceous material, in the form of brine by draining through the second outlet orifice, outside the enclosure.

According to an advantageous configuration, the second outlet orifice is arranged below the second water injection orifice so that the brine can be evacuated by gravity draining.

The enclosure is advantageously made of a metallic material adapted to the operating conditions of temperature and pressure: it can be made of Inconel®, stainless steel, refractory steel or others.

The side wall includes heating means for heating at least a portion of the height of the side wall to a temperature greater than or equal to the critical water and salt precipitation temperature.

For the means of heating the side wall of the enclosure, several alternatives can be considered which can be combined with one another: - external heating means arranged around the side wall of the enclosure to heat the water and the balls to a temperature greater than or equal to the critical temperature of the water and precipitation of the salts;

- heating resistors, in the form of cartridges, intended to be powered by an external electrical power source and integrated into the thickness of the side wall of the enclosure to heat the water and the beads to the higher temperature or equal to the critical temperature of water and precipitation of salts;

- a heat transfer fluid circuit produced in the thickness of the side wall of the enclosure for the water and the balls at a temperature greater than or equal to the critical temperature of the water and precipitation of salts. As a heat transfer fluid, an injection of an oxygen-rich fluid intended to produce an exothermic chemical reaction between a carbonaceous material, preferably that not previously converted in a conversion reactor, and the oxygen of the fluid can be carried out upstream. .

Preferably, the operating pressure of the enclosure is between 222 bars and 300 bars.

More preferably, the temperature of the interior chamber in the heating zone (Ch) is of the order of 420°C.

More preferably, the temperature of the interior chamber in the resolubilization zone is of the order of 300°C.

The invention also relates to a method of operating a salt separator as described above, comprising the following steps:

- injection of the carbonaceous material through the first injection orifice inside the hollow cylinder and injection of water through the second injection orifice into the interior chamber, at a pressure above its critical pressure but at a temperature below its critical temperature,

- rotation of the endless screw so as to cause the balls to move in a loop comprising: a heating zone, outside the endless screw, along the side wall of the enclosure in which the water and the balls are heated by it to a temperature greater than or equal to the critical temperature of the water and precipitation of salts, downstream of the heating zone, a precipitation zone inside the hollow cylinder, in which on contact with the hot balls, the salts contained in the carbonaceous material precipitate, downstream of the precipitation zone, a resolubilization zone , between the lower end of the hollow cylinder and the grid in which the salts precipitated on the balls are dissolved then evacuated through the grid, with where appropriate the salts in particulate form present in the carbonaceous material, in the form of brine by draining through the second outlet port, outside the enclosure.

The invention also relates to a biomass gasification installation comprising:

- a salt separator as described previously;

- a gasification reactor connected to the salt separator enclosure to be supplied with salt-free biomass.

Advantageously, the operating temperature of the reactor is approximately 600° C. and the operating pressure of the reactor is approximately 300 bars.

Thus, the invention essentially consists of producing a separator of salts contained in a solution, preferably to be converted thermochemically, which is carried with moving balls by means of a screw, under supercritical conditions.

The movement of the heated balls brings them into the hollow cylinder of the endless screw where their temperature, higher than the precipitation temperature of the salts, allows the salts to be deposited on the surface of the balls.

The movement of the heated balls in a loop first allows the solution to be converted to be heated to a temperature guaranteeing the precipitation of the salts on the balls and then to separate the solution to be converted into a flow depleted of salts which is evacuated from the separator for be directed to a conversion reactor, in particular a gasification reactor, and into a flow loaded with dissolved salts to be extracted in the form of a brine evacuated by draining, preferably by gravity through a grid.

Other advantages and characteristics will become clearer on reading the detailed description, given for illustrative and non-limiting purposes, with reference to the following figures. Brief description of the drawings

[Fig 1] Figure 1 is a schematic longitudinal sectional view of a salt separator according to the state of the art.

[Fig 2] Figure 2 is a perspective view of a salt separator according to the invention.

[Fig 3] Figure 3 repeats Figure 2 and shows the separator in operation with the fluid circulations indicated.

[Fig 4] Figure 4 is a perspective view of a first variant of mounting the endless screw according to the invention which shows the attachment of its rotation shaft to the hollow cylinder and its arrangement in relation to the enclosure of the separator.

[Fig 5] Figure 5 is a perspective view of a second variant of mounting the endless screw according to the invention which shows the attachment of its rotation shaft to the hollow cylinder and its arrangement in relation to the enclosure of the separator.

[Fig 6] Figure 6 is a synoptic view of a wet biomass gasification installation integrating a salt separator according to the invention.

detailed description

For the sake of clarity, the same elements are designated by the same numerical references according to the state of the art and according to the invention.

It is specified that throughout the application, the terms “inlet”, “outlet”, “upstream”, “downstream” are to be understood in relation to the direction of circulation of the fluid considered within a salt separator. and a gasification installation according to the invention.

Likewise, the terms “upper”, “lower”, “above”, “below” are to be understood with reference to a salt separator according to the invention arranged vertically in its operating configuration.

Figure 1 relating to a salt separator according to the state of the art has already been commented on in the preamble. It will therefore not be hereafter.

In Figure 2, there is shown a salt separator 1 according to one embodiment of the invention. In the example illustrated, the salt separator 1 has an axisymmetric shape of revolution. In its installed configuration, it extends vertically. This separator 1 comprises an enclosure 2 delimiting an interior chamber C including a zone S for separating the precipitated salts.

The cover 26 of the enclosure is pierced with the injection orifice 11 through which the wet biomass containing salts is injected. The cover is also pierced with at least a first outlet 25 through which the effluents of the biomass devoid of precipitated salts are intended to be evacuated.

The enclosure 2 can have a single metal side wall 20, pierced with a second injection orifice 27 through which water is intended to be injected. The side wall 20 is also pierced with a second outlet orifice 23 through which the precipitated salts are intended to be evacuated in the form of brine. This second outlet 23 is arranged below the second water injection orifice 27 so that the brine can be evacuated by gravity draining.

At least part of the height of the side wall 20 is adapted to be heated. For this heating, heating resistors, in the form of cartridges, intended to be powered by an external electrical power source can be advantageously integrated into the thickness of the single 20 or double metal wall 20, 21 It can be use cylindrical cartridges of small diameter, typically equal to 3.15mm, such as those marketed by the Omega company: https://www.omega.fr/subsection/cartouches-heaters.html.

A grid 13 is arranged in the interior chamber C of enclosure 2 at a height between the second injection port 27 and the second outlet port 23.

Balls 14 are contained in the interior chamber C of enclosure 2. They are dimensioned so as not to pass through the grill 13. The balls 14 are made of refractory material, for example Inconel®, stainless steel or other refractory steels . The diameter of the balls 14 is preferably between 0.5 mm and 2 mm.

The separator 1 comprises a hollow cylinder 15 opening at its two ends 150, 151. It comprises, on its outer periphery, a helical groove 16 forming an endless screw 17 mounted to rotate around a central axis interior of the interior chamber C of enclosure 2. As illustrated in Figure 2, the assembly of this endless screw 17 is carried out so that the first injection orifice 11 opens inside the hollow cylinder 15 with the lower end 150 of the hollow cylinder 15 arranged above of the grid 13 and the upper end 151 of the hollow cylinder 15 arranged at a distance from the cover 26 sufficient to allow the balls 14 to pass from the outside of the hollow cylinder 15 towards the inside of the hollow cylinder 15. As shown in this figure 2, the first injection orifice 11 can be that of an injection tube 10 in the form of a rod which brings the biomass into the hollow cylinder 15.

The operation of separator 1 will now be described with reference to Figure 3.

The biomass is injected through the first injection orifice 11 inside the hollow cylinder 15, typically at a temperature of 300°C, into the bed of balls 14 which are at a temperature of the order of 420°C per the heating of the side wall 20, as detailed below.

Water is injected into the interior chamber C through the second injection port 27 at a pressure above its critical pressure but at a temperature below its critical temperature, typically 300°C.

The rotation of the endless screw 17 causes the balls 14 to move in a loop comprising:

- a heating zone (Ch), outside the endless screw, along the side wall 20 of the enclosure in which the water and the balls 14 are heated by it to a higher temperature or equal to the critical temperature of water and salt precipitation, typically at 420°C

- downstream of the heating zone, a precipitation zone (P) inside the hollow cylinder 15, in which on contact with the hot balls, the salts contained in the biomass precipitate,

- downstream of the precipitation zone, a resolubilization zone (R), between the lower end 151 of the hollow cylinder and the grid 13 in which the salts precipitated on the balls are dissolved then evacuated, with where appropriate the salts under particulate form present in the carbonaceous material, in the form of brine by draining through the second orifice, outside the enclosure. Thus, on contact with the hot balls 14, gases are formed in the precipitation zone P and circulate countercurrent to the balls 14 then are evacuated through the outlet orifice 25.

In contact with the hot balls, the inorganic salts contained in the biomass are deposited on the balls 14 and are carried away by the circulation of the balls 14 in a loop towards the resolubilization zone R at the bottom of the reactor for evacuation by gravity draining through the orifice of exit 23.

The operation of the separator 1 therefore requires that the balls be heated to a temperature such that the temperature within the enclosure 2 is of the order of 420 ° C so that the salts are deposited on the balls and the organic compounds of the injected biomass are evacuated with the water in supercritical conditions through the outlet orifice 25 at the top of the separator.

The beads must therefore provide the energy to heat the biomass to this temperature. This temperature depends on the flow rate of balls circulating in the external zone of the screw. For example, for a flow rate of Ikg/h of resource entering separator 1 at 300°C 280 bars, a flow rate of 76kg/h is required to inject balls 14 at 460°C and maintain separator 1 at 420°C . The power provided by the balls 14 to the biomass is then 0.3 kW.

An additional power of 1.2 kW would be required to heat the balls from 300°C to a temperature of 460°C. Thus, the balls which emerge from the annular space between the screw and the wall of the enclosure have a hot temperature of 460°C, such that the energy they transfer to the medium within the enclosure corresponds to the energy which is supplied to the biomass.

Different variants of mounting the endless screw 17 and the biomass injection rod 10 can be provided within the framework of the invention.

Figure 4 shows a variant according to which the injection rod 10 is arranged at a distance from the rotation shaft 19 and opens near the upper end 151 of the hollow cylinder 15. The attachment between the rotation shaft 19 and the hollow cylinder 15 is made only with its lower end 150 by means of fixing lugs 152 which extend radially, preferably being uniformly distributed radially.

Figure 5 shows another variant according to which the injection rod 10 is arranged inside the rotation shaft 19 and opens near the lower end 150 of the hollow cylinder 15. The fixation between the rotation shaft 19 and the hollow cylinder 15 is carried out both with its lower end 150 and with its upper end by means respectively of fixing lugs 152 and 153 which extend radially, preferably being uniformly distributed radially.

Figure 6 illustrates a wet biomass gasification installation 3 which integrates a salt separator 1 according to the invention.

In this figure 6, the different symbols relating to temperatures are as follows:

T: heating temperature of the biomass to be converted before entering separator 1, typically around 300°C.

Tg: gasification temperature of biomass, typically around 600°C.

This installation 3 includes from upstream to downstream in the direction of the circulation of biomass to be gasified:

- a heat exchanger 4, which can be standard in the management of non-sticky viscous fluid and optimized for heat recovery between ambient temperature and maximum temperature T,

- a salt separator 1, connected downstream to the heat exchanger 4, which makes it possible to evacuate the biomass effluent without salts while separating the salts in the form of brine,

- a high pressure separator 5, connected downstream to the separator 1, to separate the precipitated salts in solid form from the evacuated brine water;

- a gasification reactor 6, connected downstream to the salt separator 1 to gasify the biomass without salts at the temperature Tg.

The gasification reactor 6 is typically a tube-and-shell reactor and operates at 600°C under pressure of 300 bar.

In this figure 6, the solid lines symbolize the material flows before gasification, respectively at a cold (ambient) temperature at the inlet of exchanger 4, at a temperature close to T at the outlet of exchanger 4, then at the required gasification temperature Tg from the outlet of separator 1. The dotted lines represent the post-gasification material flows which exit at temperature Tg from reactor 6 and pass back into heat exchanger 4 to be cooled.

As shown in Figure 6, once cooled, the effluents converted by gasification (syngas) are evacuated from installation 3 to a storage or direct exploitation process.

Other variants and improvements can be considered without departing from the scope of the invention.

List of cited references

[1]: “A novel salt separator for the supercritical water gasification of biomass”, J Reimer, G. Peng, S. Viereck, E. De Boni, J. Breinl, F. Vogel, J. of Supercritical Fluids 117 (2016 ) 113-121.

[2]: “Continuous salt precipitation and separation from supercritical water. Part 1: Type 1 salts”, Martin Schubert, Johann W. Regler, Frederic Vogel, J. of Supercritical Fluids 52 (2010) 99-112.

[3]: “Continuous salt precipitation and separation from supercritical water. Part 2. Type 2 salts and mixtures of two salts”, Martin Schubert, Johann W. Regler, Frederic Voge, J. of Supercritical Fluids 52 (2010) 113-124.

Claims

1. Salt separator (1) for separating salts from a carbonaceous material containing them, the salt separator comprising:

- an enclosure (2) delimiting an interior chamber (C) and comprising: a cover (26) pierced with a first injection orifice (11), through which a carbonaceous material containing one or more salts is intended to be injected, at least one side wall (20, 21) pierced with a second injection orifice (27), through which water is intended to be injected, at least part of the height of the side wall being adapted to be heated, the side wall and/or the cover being pierced with at least a first outlet orifice (25) through which the effluents of the carbonaceous material devoid of precipitated salts are intended to be evacuated, a bottom (24) , the side wall and/or the bottom being pierced with at least a second outlet orifice (23) through which the precipitated salts are intended to be evacuated in the form of brine;

- a grid (13) arranged in the interior chamber of the enclosure;

- balls (14) contained in the interior chamber of the enclosure and sized not to pass through the grid;

- a hollow cylinder (15) opening at its two ends (150, 151), the cylinder (15) comprising, on its outer periphery, a helical groove (16) forming an endless screw (17), the endless screw end being mounted in rotation inside the interior chamber of the enclosure so that the first injection orifice (11) opens inside the hollow cylinder, that the lower end (150) of the hollow cylinder is arranged above the grid (13) and that the upper end (151) of the hollow cylinder is arranged at a distance from the cover (26) sufficient to allow the balls (14) to pass from the outside of the hollow cylinder towards the inside the hollow cylinder.

2. Salt separator according to claim 1, the second outlet orifice being arranged below the second water injection orifice so that the brine can be evacuated by gravity draining.

3. Salt separator according to claim 1 or 2, comprising external heating means arranged around the side wall of the enclosure to heat the water and the balls to the temperature greater than or equal to the critical temperature of the water and precipitation of salts.

4. Salt separator according to one of the preceding claims, comprising heating resistors, in the form of cartridges, intended to be powered by an external electrical power source and integrated into the thickness of the side wall of the enclosure to heat the water and the beads to the temperature greater than or equal to the critical temperature of the water and precipitation of salts.

5. Salt separator according to one of the preceding claims, comprising a heat transfer fluid circuit produced in the thickness of the side wall of the enclosure for the water and the balls at the temperature greater than or equal to the critical temperature of water and precipitation of salts.

6. Salt separator according to one of the preceding claims, the operating pressure of the enclosure being between 222 bars and 300 bars.

7. Salt separator according to one of the preceding claims, the temperature of the interior chamber in the heating zone (Ch) being of the order of 420°C.

8. Salt separator according to one of the preceding claims, the temperature of the interior chamber in the resolubilization zone (R) being of the order of 300°C.

9. Method of operating a salt separator according to one of the preceding claims, comprising the following steps:

- rotation of the endless screw so as to cause the balls to move in a loop comprising: a heating zone, outside the endless screw, along the side wall of the enclosure in which the water and the balls are heated by it to a temperature greater than or equal to the critical temperature of the water and precipitation of salts, downstream of the heating zone, a precipitation zone inside the hollow cylinder, in which on contact with the hot balls, the salts contained in the carbonaceous material precipitate, downstream of the precipitation zone, a resolubilization zone, between the lower end of the hollow cylinder and the grid in which the salts precipitate on the balls are dissolved then evacuated through the grid, with where appropriate the salts in particulate form present in the carbonaceous material, in the form of brine by draining through the second outlet orifice, outside the enclosure.

10. Biomass gasification installation (3) comprising: - a salt separator (1) according to one of claims 1 to 8;

- a gasification reactor (6) connected to the salt separator enclosure (1) to be supplied with salt-free biomass.

11. Installation according to claim 10, the operating temperature of the reactor being approximately 600°C and the operating pressure of the reactor being approximately 300 bars.