Salt separator comprising a deformable porous structure forming a support for precipitation and discharge of salts, associated biomass gasification facility

Abstract

The invention relates to a separator for salts contained in a solution which is brought under supercritical conditions in order to precipitate the salts that it contains within a deformable porous structure. The open porosity of the pores of the structure defines a very large deposition / salt precipitation surface. The solution is injected into the enclosure of the separator by a tube which can reach the inside of the chamber and penetrate into the deformable structure, even in its most deformed state. The porous structure is heated via the side wall of the enclosure at a temperature between 300°C and 1000°C. The inorganic salts contained in the solution are trapped / precipitated in contact with the heated porous structure which is in its deformed state. The flow of the salt-depleted solution is discharged through the dedicated outlet.

Description

[0001] Description

[0002] Title: Salt separator comprising a deformable porous structure forming a support for precipitation and evacuation of salts, associated biomass gasification installation.

[0003] Technical field

[0004] The present invention relates generally to salt separators and more particularly to those intended to be implemented in a thermochemical conversion installation of a carbonaceous material feedstock, in particular under supercritical fluid, for the production of a gaseous mixture.

[0005] By "carbonaceous material load" is meant here and within the scope of the invention any material containing a quantity of carbon, in particular any carbonaceous material from residues.

[0006] It can therefore be biomass, that is to say any inhomogeneous material of plant origin containing carbon, such as lignocellulosic biomass, forest or agricultural residues (straw), which can be almost dry or soaked in water like household waste or waste resulting from water treatment such as sewage treatment plant sludge.

[0007] It can also be a fossil fuel, such as coal.

[0008] It may 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.

[0009] It can also be a combination of biomass and fossil fuel.

[0010] By "supercritical fluid" is meant here and within the scope 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.

[0011] 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.

[0012] Although described with reference to a preferred application of gasification of a carbonaceous material feedstock under supercritical water, a salt separator according to the invention can be implemented in numerous applications, and particularly in the industrial fields of food processing, chemistry, energy, including the oil sector and the transport sector, ... for which a separation of salts from an aqueous fluid mixture is required.

[0013] Generally, a salt separator according to the invention is suitable for the separation of salts initially present in aqueous solutions with or without organic matter.

[0014] More specifically, a salt separator according to the invention is advantageously implemented in a thermochemical conversion installation for wet carbon resources, such as supercritical water gasification.

[0015] Prior art

[0016] Many existing processes allow the thermochemical conversion of a carbon feedstock into liquid (biofuels, biochar), solid (pellets), and gaseous (biogas, methane, syngas, hydrogen) fuels.

[0017] Among these, 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 gasifying agents. The aim is to generate, at the end of gasification, a mixture of gases.

[0018] Thus, the gasification processes of lignocellulosic biomass make it possible to generate a gas rich in methane or hydrogen.

[0019] More specifically, hydrothermal gasification, also known as supercritical water gasification, is a thermochemical process for producing renewable gas from wet organic matter, typically containing a dry matter content of between 5 and 20% by mass, such as food industry waste, industrial effluents such as black liquor, non-spreadable methanization digestates and sewage treatment plant sludge. By operating at high temperature and pressure, the process generates a high-energy synthesis gas, composed of a mixture rich in methane, hydrogen, carbon dioxide (syngas) and other light hydrocarbons.

[0020] By exploiting the properties of water in supercritical conditions, i.e. at a temperature above 374°C and a pressure above 221 bar, the medium becomes very reactive, which allows hydrothermal gasification to achieve excellent conversion rates of biomass carbon into gas, around 70-90%, while separating the inorganic elements (salts), potentially allowing their recovery into nutrients, in particular the elements nitrogen, phosphorus, and potassium.

[0021] Generally, the separation and recovery of inorganic constituents present in the feed stream of reactors that implement thermochemical processes is crucial, as these constituents can lead to blockage of the plant, fouling and poisoning of the gasification catalyst. In addition, the recovery of salts offers the possibility of producing a fertilizer as a valuable by-product (nutrients), as explained above.

[0022] This problem of salt separation is even more pressing in the case of gasification in supercritical water: the evolution of the dielectric constant and the ionic product of water in the supercritical state lead to the precipitation of the salts contained in the resource. Indeed, near the critical point, the properties of the water change with a significant drop in the density and the dielectric constant of the water, among others. Under these conditions, the atoms of the inorganic components that could be dissolved / transported in the water, below the critical point are no longer. Some of these salts can modify the physical properties of the water and form a dense phase that flows to the bottom of the reactor, but most precipitate and then agglomerate on the hot surfaces and cause blockages of the reactors and induce intermittent shutdowns of the related installation.The management of precipitation and the location of this precipitation is a key element for the development of hydrothermal gasification.

[0023] Numerous articles in the literature show that salt separation in a thermochemical conversion process is of major importance for the actual efficiency of the overall process and for the lifetime of the associated plant. However, the disadvantage of the salt separators known so far is that the salt separation is still not satisfactory or, although satisfactory, requires too high thermal or mechanical energy inputs or the salts are associated with a significant proportion of organic matter. In addition, clogging and deposits are a major problem in such salt separators.

[0024] More particularly, various scientific articles are interested in the dynamics of salt precipitation under supercritical hydrogenation conditions, which makes it possible to separate salts initially present in 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 an inner chamber C delimited by a double-walled enclosure 2 20, 21, the outer one 21 of which, thermally insulating, integrates heating elements 22 which thus heat the chamber C and the injection tube 10.

[0025] When the wet biomass is introduced into the 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 the separation of the wet biomass into various phases, notably solids in a separation zone S within the chamber C.

[0026] In the configuration installed vertically of the separator, the biomass / water / salts and other solids mixture, this separation zone S generates a gravity separation into a brine highly 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 pierced 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.

[0027] 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.

[0028] Overall, a gravity separator operates satisfactorily when the phases involved are denser than the carrier medium and according to a grain size distribution allowing gravity separation and brine-type behavior, salts which are qualified as type I in this case.

[0029] However, in some cases, the salts precipitate into particles so small (micro or nanoparticles) that they do not sediment.

[0030] 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 are called type II. These type II salts can accumulate on the internal walls of the inner chamber of the separator and, if necessary, clog the injection tube 10 of the separator as shown in Figure 1.

[0031] To avoid such harmful accumulation of II salts, one could consider applying known solutions, implemented in scraped surface type heat exchangers. Such exchangers are particularly used in fouling processes, i.e. when the walls of the exchangers can be the site of fouling phenomena of the walls involved in heat transfers, i.e. with deposition of undesirable materials.

[0032] For example, the scrapers used can be rotary, for example of the worm or blade type, or oscillating 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.

[0033] Scrapers for heat exchangers have been particularly considered for supercritical oxidation reactors, as described in US patents 5,100,560A, US6,054,057 A and US5,461,648 A.

[0034] 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 / .

[0035] In the field of organic fluids, other defouling solutions have already been considered, including:

[0036] - the vibration of parts by pressure pulsation, as described in application US2008 / 0073063A1,

[0037] - chemical treatments, such as that of patent application CA 2119056.

[0038] All 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.

[0039] There is therefore a need to find a solution which allows better control of the elimination of salts, in particular type II salts, present in a solution, in particular a solution intended to undergo a thermochemical conversion treatment such as wet biomass intended to be gasified.

[0040] The aim of the invention is to meet at least part of this need.

[0041] Statement of the invention

[0042] To this end, the invention relates to a salt separator for separating salts from a carbonaceous material containing them, the salt separator comprising:

[0043] - a tube comprising an injection orifice through which a solution containing one or more salts is intended to be injected, and an outlet orifice through which the solution is intended to be evacuated;

[0044] - an enclosure delimiting an interior chamber and comprising:

[0045] • a cover to which the tube is fixed or made entirely,

[0046] • at least one side wall pierced with a second injection orifice, through which a draining fluid is intended to be injected, at least part of the height of the side wall being adapted to be heated to a temperature greater than or equal to the precipitation temperature of the salts, the side wall and / or the cover being pierced with at least one first outlet orifice through which the effluents of the carbonaceous material devoid of the precipitated salts are intended to be evacuated,

[0047] • a base, the side wall and / or the cover and / or the base being pierced with at least one outlet orifice through which the precipitated salts are intended to be evacuated in the form of brine or in the form of solids by being drained by the draining fluid;

[0048] - a grid arranged in the inner chamber of the enclosure;

[0049] - a deformable porous structure, arranged in the chamber (C) of the enclosure above the grid so that the outlet orifice of the tube opens into it when it is in its undeformed state;

[0050] - at least one deformation means, arranged in the chamber of the enclosure above the grid, the deformation means being actuated to reversibly deform, at least once, the structure from an undeformed state, in which, when the solution is injected into the tube, the salts contained in the solution precipitate on its surface, to at least one deformed state in which, in the absence of injected solution, the precipitated salts present on the surface of the latter detach. According to a first advantageous embodiment, the deformable structure is a compressible structure, the deformation means being a compression means for compressing the compressible structure in the interior chamber from an uncompressed state to at least one compressed state.

[0051] According to this first embodiment and an advantageous variant embodiment, the compressible structure consists of at least one compressible foam with open pores, coated or not with a catalytic coating, or at least one compression spring, preferably a plurality of compression springs arranged concentrically. A metallic or ceramic foam advantageously has essentially open porosity, which makes it accessible and allows a high capacity for retaining precipitated salts.

[0052] Advantageously, the compressible structure is arranged to scrape the wall of the inner chamber as it passes from its uncompressed state to its compressed state. By scraping the inner wall of the enclosure in this way, it is cleaned by removing any particles and / or precipitated salt.

[0053] According to an advantageous embodiment variant, the compression means consists of a piston mounted to slide in the interior chamber and actuated by a motor arranged outside the enclosure.

[0054] According to an advantageous configuration, the outlet orifice for the precipitated salts in solid form being drained by the draining fluid is the first outlet orifice through which the effluents of the carbonaceous material devoid of the precipitated salts are intended to be evacuated.

[0055] According to a second advantageous embodiment, the deformable structure is a bed of balls, the deformation means being an agitation means for agitating the bed of balls in the interior chamber from a static state to at least one agitated state.

[0056] According to this second mode and an advantageous variant embodiment, the stirring means is a mechanical stirrer, in particular with blades, mounted in rotation in the interior chamber and actuated by a motor arranged outside the enclosure.

[0057] According to an advantageous configuration, the outlet orifice for the precipitated salts in the form of brine is a second outlet orifice arranged below the second injection orifice, so that the brine can be evacuated by gravity drainage. 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 or others.

[0058] The side wall comprises heating means for heating at least a portion of the height of the side wall to a temperature greater than or equal to the precipitation temperature of the salts.

[0059] For the means of heating the side wall of the enclosure, several alternatives can be considered which can be combined with each other:

[0060] - external heating means arranged around the side wall of the enclosure to heat the solution to a temperature greater than or equal to the critical temperature of water and salt precipitation;

[0061] - 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 solution to a temperature greater than or equal to the critical temperature of water and precipitation of salts;

[0062] - a heat transfer fluid circuit made in the thickness of the side wall of the enclosure to heat the solution to a temperature greater than or equal to the critical temperature of water and precipitation of salts.

[0063] Preferably, the operating pressure of the enclosure is between 222 bars and 1000 bars.

[0064] More preferably, the temperature of the inner chamber is between 300°C and 1000°C.

[0065] The invention also relates to a method for operating a salt separator as described above, comprising the following successive steps: i / injecting a solution through the first injection orifice and heating the enclosure so that the solution is at a temperature greater than or equal to the critical temperature of water and precipitation of the salts, the deformable porous structure being in the undeformed state; ii / stopping the injection of solution then actuating the deformation means to change the deformable porous structure from its undeformed state to at least one deformed state; iii / stopping the actuation of the deformation means to return the deformable porous structure to its undeformed state then injecting a draining fluid to drain the precipitated salts detached from the structure towards the outlet orifice in the form of brine or in the form of solids.

[0066] Advantageously, steps i / to iii / are repeated continuously or with a waiting period between step iii / and the successive step i / .

[0067] The invention also relates to a biomass gasification installation comprising:

[0068] - a salt separator as described previously;

[0069] - a gasification reactor connected to the salt separator enclosure to be supplied with salt-free biomass.

[0070] Advantageously, the operating temperature of the reactor is approximately 600°C and the operating pressure of the reactor is approximately 300 bars.

[0071] Thus, the invention essentially consists of producing a separator of salts contained in a solution, preferably to be converted thermochemically, which is brought under supercritical conditions to precipitate the salts which it contains within a deformable porous structure.

[0072] The open porosity of the pores of the structure defines a very large surface area for deposition / precipitation of salts.

[0073] The solution is injected into the separator enclosure by a tube, such as an injection rod, advantageously adjustable in height, able to reach the interior of the chamber and penetrate into the deformable structure, even in its most deformed state.

[0074] The porous structure is heated through the side wall of the enclosure to a temperature between 300°C and 1000°C, for example 400°C. The inorganic salts contained in the solution are trapped / precipitated upon contact with the heated porous structure which is in its deformed state. The salt-depleted solution flow is discharged through the dedicated outlet.

[0075] After a certain period of time, the injection of the solution is stopped. The deformation of the structure either by compression on a grid, and if necessary decompression, or by agitation (ball bed) according to a cycle makes it possible to detach / dislocate the salts precipitated within the structure. Then, a flow of draining fluid, which can be water or a solvent or a carrier gas is injected through the dedicated orifice. The draining fluid is advantageously injected at a temperature between 300°C and 1000°C, for example 300°C, and at a pressure between 222 bar and 1000 bar, for example 250 bar.

[0076] When the structure is a compressible structure, the draining fluid flows through the structure which has been returned to its uncompressed state and evacuates / drains the salt particles which have been detached from the porous structure. The draining fluid exits through the upper part of the separator, transporting these particles to the outside. They can advantageously be evacuated through the outlet orifice dedicated to the evacuation of the flow of the solution depleted in salts. The salt particles can be advantageously separated from the draining fluid for recovery and recovery of the inorganics.

[0077] When the structure is a structure deformable by agitation (bed of balls), the draining fluid sweeps the bottom of the separator and therefore becomes loaded with dissolved salts to be extracted in the form of brine evacuated by draining, preferably by gravity through a grid.

[0078] Other advantages and characteristics will become more apparent upon reading the detailed description, given for illustrative and non-limiting purposes, with reference to the following figures.

[0079] Brief description of the drawings

[0080] [Fig 1] Figure 1 is a schematic longitudinal sectional view of a salt separator according to the state of the art.

[0081] [Fig 2 A] [Fig 2B] [Fig 2C] Figures 2 A, 2B, 2C are longitudinal sectional views illustrating the different stages of operation of a salt separator according to a first embodiment of the invention.

[0082] [Fig 3] Figure 3 illustrates in longitudinal sectional view a first variant of a salt separator according to the first embodiment according to the invention.

[0083] [Fig 4] Figure 4 illustrates in longitudinal sectional view a second variant of a salt separator according to the first embodiment according to the invention.

[0084] [Fig 5] Figure 5 illustrates in longitudinal section a salt separator according to a second embodiment according to the invention. [Fig 6] Figure 6 is a synoptic view of a wet biomass gasification installation integrating a salt separator according to the second embodiment of the invention.

[0085] Detailed description

[0086] 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.

[0087] 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.

[0088] 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.

[0089] Figure 1 relating to a state-of-the-art salt separator has already been commented on in the preamble. It will therefore not be commented on below.

[0090] Figure 2A shows a salt separator 1 according to a first embodiment of the invention. In the example illustrated, the salt separator 1 is of axisymmetrical shape of revolution. In its installed configuration, it extends vertically.

[0091] This separator 1 firstly comprises an injection orifice 11 through which the wet biomass containing salts is injected, and an outlet orifice 12 through which it is evacuated.

[0092] The separator 1 also comprises an enclosure 2 delimiting an interior chamber C.

[0093] The cover 26 of the enclosure is crossed by the injection tube 10 advantageously mounted adjustable in height so as to inject the biomass into a salt precipitation zone.

[0094] The cover is also pierced with at least one first outlet orifice 25 through which the effluents from the biomass free of precipitated salts are intended to be evacuated.

[0095] The enclosure 2 may have a single metal side wall 20 or a double metal wall 20, 21, pierced with a second injection orifice 23 through which water is intended to be injected.

[0096] At least a portion 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 may be cylindrical cartridges of small diameter, typically equal to 3.15 mm like those marketed by the company Omega: https: / / www.omega.fr / subsection / cartouches-chauffees.html.

[0097] A grid 13 is arranged in the inner chamber C of the enclosure 2, preferably above the first outlet orifice 23.

[0098] A deformable porous foam 14 is arranged in the chamber C of the enclosure above the grid 13 so that the outlet orifice 12 of the tube opens into it when it is in its uncompressed state. The porous foam 14 may be a high temperature resistant metal foam.

[0099] Finally, a compression means 15 is arranged in the chamber C of the enclosure above the grid 13 to compress the porous foam 14.

[0100] The operation of the separator 1 will now be described with reference to Figures 2A to 2C. is heated and wet biomass is injected through the tube 10 into the metal foam 14 which is in its uncompressed state, typically at a temperature of 300°C, and at a pressure above the critical pressure beyond 222 bars (figure 2A).

[0101] The salts contained in the biomass then precipitate on the surface of the metal foam 14.

[0102] The salt-free biomass effluents are discharged from the enclosure through the outlet orifice 25.

[0103] The biomass injection is stopped. The compression means 15 is actuated to change the deformable porous structure from its uncompressed state to at least one compressed state (FIG. 2B). Several compressions / decompressions can be carried out. These mechanical stresses on the metal foam 14 cause the detachment or in other words the detachment / dislocation of the salts precipitated previously in the metal foam 14. The compression deformation of the metal foam 14 is stopped to return it to its uncompressed state. Water is then injected as a draining fluid through the injection orifice 23 to drain the precipitated salts detached from the foam 14 in a solid form towards the outlet orifice 25 (FIG. 2C).

[0104] Figure 3 shows a first variant embodiment of the compression means 15 in the form of a piston mounted to slide in the inner chamber C and actuated by a motor 16 arranged outside the enclosure.

[0105] The compression piston here consists of a compression plate 150 moved in translation by a screw 151. The screw 151 is mounted in rotation about a central axis X inside the inner chamber C of the enclosure 2 and the compression plate 150 is screwed and fixed around the screw 151. Guide pins 152 ensure the translational guidance of the plate 150 inside the enclosure 2, that is to say they prevent the rotation of the compression plate 150 and therefore only ensure its translation when the screw 151 is actuated by rotation by the motor 16. The compression plate 150 is further pierced with a through hole 153 to allow the injection tube 10 to pass through.

[0106] Figure 4 shows another alternative embodiment of the structure deformable by a plurality of compression springs 17 arranged concentrically. The compression piston here consists of a rod 154 connected to or made integrally with the compression plate 150 which can be actuated by reciprocating movement by the motor 16. The injection tube 10 can act as a sliding guide for the compression plate 150.

[0107] Whatever the embodiment of the compression-deformable structure (metal foam 15, concentric springs 17), it is sized so that it also scrapes the wall of chamber C. This guarantees, to some extent, the cleaning of the latter by removing any inorganic particles which may have been deposited on this surface.

[0108] Figure 5 illustrates another embodiment of the invention according to which, instead of a porous structure deformable by compression, a bed of balls 18 deformable by mechanical agitation is implanted within the enclosure 2.

[0109] To carry out the mechanical agitation, a paddle-type agitator 19 which can be actuated by a motor 16 is arranged inside the chamber C. The aforementioned step ii / is thus carried out by rotating the mechanical agitator 19 which will cause agitation of the balls 18 and thereby dislocation of the salts precipitated beforehand on their surface. These dislocated salts will sediment in the lower part of the separator 1, i.e. below and / or above the grid 13.

[0110] Thus, step iii / is carried out by injecting water through the injection orifice 23 and the dislocated salts are evacuated by gravity drainage in the form of brine through an outlet orifice 27 made in the lower part, i.e. either in the side wall 20 or in the bottom 24 of the enclosure.

[0111] Figure 6 illustrates a wet biomass gasification installation 3 which integrates a salt separator 1 according to the embodiment of figure 5.

[0112] In this figure 4, the different symbols relating to temperatures are as follows:

[0113] T: heating temperature of the biomass to be converted before entering separator 1, typically around 300°C.

[0114] Tg: biomass gasification temperature, typically around 600°C.

[0115] This installation 3 includes from upstream to downstream in the direction of circulation of biomass to be gasified:

[0116] - 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 at most temperature T,

[0117] - a salt separator 1, connected downstream to the heat exchanger 4, which allows the biomass effluents to be evacuated without salts while separating the salts in the form of brine,

[0118] - a high pressure separator 5, connected downstream to the separator 1, to separate the salts precipitated in solid form from the discharged brine water;

[0119] - a gasification reactor 6, connected downstream to the salt separator 1 to gasify the biomass without salts at temperature Tg.

[0120] Gasification reactor 6 is typically a shell-and-tube reactor and operates at 600°C under pressure of 300 bar.

[0121] 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.

[0122] The dotted lines represent the post-gasification material flows which leave at temperature Tg from reactor 6 and pass back into heat exchanger 4 to be cooled.

[0123] As specified in this figure 6, once cooled, the effluents converted by gasification (syngas) are evacuated from installation 3 to a storage or direct exploitation process.

[0124] Other variations and improvements may be envisaged without departing from the scope of the invention.

[0125] List of cited references

[0126] [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.

[0127] [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.

[0128] [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

Claims 1. Salt separator (1) for separating salts from a carbonaceous material containing them, the salt separator comprising: - a tube (10) comprising an injection orifice (11) through which a solution containing one or more salts is intended to be injected, and an outlet orifice (12) through which the solution is intended to be evacuated; - an enclosure (2) delimiting an interior chamber (C) and comprising: • a cover (26) to which the tube is fixed or made entirely, • at least one side wall (20, 21) pierced with a second injection orifice (23), through which a draining fluid is intended to be injected, at least part of the height of the side wall being adapted to be heated to a temperature greater than or equal to the precipitation temperature of the salts, the side wall and / or the cover being pierced with at least one first outlet orifice (25) through which the effluents of the carbonaceous material devoid of the precipitated salts are intended to be evacuated, • a bottom (24), the side wall and / or the cover and / or the bottom being pierced with at least one outlet orifice (25, 27) through which the precipitated salts are intended to be evacuated in the form of brine or in the solid form by being drained by the draining fluid; - a grid (13) arranged in the inner chamber of the enclosure; - a deformable porous structure (14, 17, 18), arranged in the chamber (C) of the enclosure above the grid so that the outlet orifice of the tube opens into it when it is in its undeformed state; - at least one deformation means (15; 150, 151, 152; 150, 154; 19), arranged in the chamber of the enclosure above the grid, the deformation means being actuated to reversibly deform, at least once, the structure from an undeformed state, in which, when the solution is injected into the tube, the salts contained in the solution precipitate on its surface, to at least one deformed state in which, in the absence of injected solution, the precipitated salts present on the surface of the latter detach.

2. Salt separator according to claim 1, the deformable structure being a compressible structure (14, 17), the deforming means being a compression means (15; 150, 151, 152; 150, 154) for compressing in the inner chamber the compressible structure from an uncompressed state to at least a compressed state.

3. Salt separator according to claim 2, the compressible structure consisting of at least one compressible open-pore foam, coated or not with a catalytic coating, or at least one compression spring, preferably a plurality of compression springs arranged concentrically.

4. A salt separator according to claim 2 or 3, the compressible structure being arranged to scrape the wall of the inner chamber as it passes from its uncompressed state to its compressed state.

5. Salt separator according to one of claims 2 to 4, the compression means being constituted by a piston (150, 151, 152; 150, 154) slidably mounted in the inner chamber and actuated by a motor arranged outside the enclosure.

6. Salt separator according to one of claims 2 to 5, the outlet orifice for the precipitated salts in solid form being drained by the draining fluid being the first outlet orifice (25) through which the effluents of the carbonaceous material devoid of the precipitated salts are intended to be evacuated.

7. Salt separator according to claim 1, the deformable structure being a bed of beads (18), the deforming means being an agitation means (19) for agitating in the interior chamber the bed of beads from a static state to at least an agitated state.

8. Salt separator according to claim 7, the stirring means being a mechanical stirrer, in particular with blades, mounted in rotation in the inner chamber and actuated by a motor arranged outside the enclosure.

9. Salt separator according to claim 7 or 8, the outlet orifice for the precipitated salts in the form of brine being a second outlet orifice (27) arranged below the second injection orifice (23) so that the brine can be evacuated by gravity drainage.

10. Salt separator according to one of the preceding claims, comprising external heating means arranged around the side wall of the enclosure to heat the solution to a temperature greater than or equal to the critical temperature of water and precipitation of salts.

11. 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 solution to the temperature greater than or equal to the critical temperature of the water and precipitation of the salts.

12. 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 to heat the solution to a temperature greater than or equal to the critical temperature of water and precipitation of salts.

13. Salt separator according to one of the preceding claims, the operating pressure of the enclosure being between 222 bars and 1000 bars.

14. Salt separator according to one of the preceding claims, the temperature of the inner chamber being between 300°C and 1000°C.

15. Method for operating a salt separator according to one of the preceding claims, comprising the following successive steps: i / injecting a solution through the first injection orifice and heating the enclosure so that the solution is at a temperature greater than or equal to the critical temperature of water and precipitation of the salts, the deformable porous structure being in the undeformed state; ii / stopping the injection of solution then actuating the deformation means to cause the deformable porous structure to pass from its undeformed state to at least one deformed state; iii / stopping the actuation of the deformation means to return the deformable porous structure to its undeformed state then injecting a draining fluid to drain the precipitated salts detached from the structure towards the outlet orifice in the form of brine or in the form of solids.

16. Operating method according to claim 15, steps i / to iii / being repeated continuously or with a waiting period between step iii / and the successive step i / .

17. Biomass gasification installation (3) comprising: - a salt separator (1) according to one of claims 1 to 14; - a gasification reactor (6) connected to the salt separator enclosure (1) to be supplied with salt-free biomass.

18. Installation according to claim 17, the operating temperature of the reactor being approximately 600°C and the operating pressure of the reactor being approximately 300 bars.

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