Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B25/00—Compositions containing a nitrated organic compound
  • C06B25/34—Compositions containing a nitrated organic compound the compound being a nitrated acyclic, alicyclic or heterocyclic amine
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
  • C06B21/0091—Elimination of undesirable or temporary components of an intermediate or finished product, e.g. making porous or low density products, purifying, stabilising, drying; Deactivating; Reclaiming
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
  • C06B21/0033—Shaping the mixture

Definitions

• the present invention relates to the field of granular explosives (powdered explosives, without binder) for civil or military use.
• the present invention relates to a method for recovering, from a suspension containing an explosive charge (discontinuous or dispersed phase) in a liquid (continuous phase), said explosive charge in granular and dry form.
• Such suspensions are generally obtained after crystallization processes of molecules in solution (molecules synthesized upstream).
• the invention also relates to a device, suitable for implementing said method.
• the suspension in question is filtered on a static filter.
• a cake consisting of the explosive charge in question (retained on said filter), with a high level of liquid (moisture, when the suspension in question is an aqueous suspension), is recovered.
• the cake is then spread (manually, thinly, with suitable tools) on shelves.
• the shelves loaded with this spread cake are put in an oven (hot) for 1 to 2 days.
• the dry explosive charge (containing less than 0.1% (by mass) of liquid (of moisture (see above) is recovered from said shelves, in addition to the operator's manipulation of the explosive. a risk, this process has the disadvantage of being a consumer of energy (especially in the stoving phase) and require operating times of several tens of hours.
• the patent application DE 33 38 572 describes a method and a device for the recovery of dry materials from suspensions (containing said materials).
• a single device containing a filter the suspensions are filtered and the cakes obtained on said filter are, after a possible wash, dislocated and converted into a fluidized bed of dry materials.
• the action of said hot gases through the filter, from said distribution chamber), possibly combined with the mechanical action of a stirrer to pale, transform said cakes into fluidized beds of the desired solids.
• the device described comprises a cylindrical chamber in the lower part of which is arranged on a support grid, a filter.
• the suspension is introduced via a nozzle arranged in the upper part of the enclosure.
• the cake generated on the filter can be washed by injecting a washing liquid via said nozzle.
• Said nozzle given the high flow rates of gas to be delivered, has a large diameter. It is equipped with a cover that protects it from the liquid phase of the suspension (during the filtration phase) and the possible washing liquid (during the eventual washing phase of the cake). This hood also ensures the distribution in said chamber of the injected drying gases and thus the pressurization of said chamber.
• the main subject of the present invention is therefore a process for obtaining, from a suspension of an explosive charge in a liquid, said explosive charge in granular and dry form. Said method comprises:
• the method of the invention therefore proposes to get rid of the liquid present in the filter cake (residual liquid that has not been removed on filtration), by subjecting said cake, as generated on the filter (at the end of step a), successively, a dewatering step (step b) and a disintegration / drying step (step c).
• the process of the invention makes it possible to obtain explosive charges in granular (pulverulent) form and containing, by mass, less than 1% of liquid, advantageously less than 0.1% of liquid.
• the suspensions, treated according to the process of the invention may be of the type of those treated to date according to the process of the prior art summarized in the introduction of the present text (ie generally suspensions of crystals in a non-solvent ( likely to contain a low level of solvent) obtained after the implementation of a crystallization step).
• the method of the invention is particularly suitable (but not limited to) to treat the suspensions conventionally obtained and treated, to date, according to the technique of the prior art, involving handling and baking, summarized above.
• the results obtained, under much more advantageous conditions (see below) are similar to, or better than, those obtained with said technique of the prior art.
• the process of the invention is not limited to the treatment of crystal suspensions.
• the solid phase (dispersed) suspensions involved may consist of crystals and grains, may not contain crystals and only grains.
• the shape of the solid phase (dispersed phase) suspensions in question is not critical.
• the constitutive particles of said solid phase must be of reasonable size (D 50 generally less than 1 mm, very generally less than 500 ⁇ ).
• the method of the invention is generally implemented with suspensions whose mass ratio, liquid / explosive charge, is between 5 and 20 (including extreme values).
• the critical detonation height of the explosive charge in question sets the maximum acceptable cake thickness, for safe implementation of the method of the invention.
• the filtration step of the process of the invention is not per se original. It is a filtration on static filter.
• the porosity of the filter is obviously adapted to the particle size of the suspended charge. It is suitable for stopping (almost) all of said suspended load.
• the constituent elements of the suspended charge generally have a median diameter of between 50 and 400 ⁇ .
• the pores of the filter have, themselves, a diameter, obviously less than said median diameter, generally between 30 and 200 pm.
• the static filter in question is generally a metal filter, for example a stainless steel filter. It is a priori arranged horizontally but it is quite possible to provide a slight inclination to facilitate the recovery of the dry load at the end of the process.
• the cake resting on the filter, after filtration generally has a weight ratio, liquid / explosive charge, between 1 and 8 (including extreme values). Such a mass ratio, obtained after conventional filtration, will not surprise the skilled person.
• the cake resting on the filter, after filtration usually has a height (thickness) of 5 to 20 cm.
• the method of the invention does not present a priori of little interest if it is implemented for the recovery of a very small amount of filler (cake of a height less than 5 cm) and the skilled person comprises that the management of the following process steps (steps b and c of said process), during which the explosive charge has a reduced humidity level, can be tricky, with reference to the critical detonation height of the load concerned, with cakes having a high thickness (thickness obviously related to that of the cakes obtained at the end of the filtration (hence the limitation in thickness, generally at most 20 cm, of said cakes obtained at the end of filtration)) .
• the cake obtained on the filter remains on the filter and it is, initially, wrung out. It is drained by pressurizing gas (pressure generated upstream thereof).
• Spinning carried out by pressurizing gas is advantageously with gases under pressure, between 2 ⁇ 10 5 and 3 ⁇ 10 5 Pa absolute (2 and 3 bar absolute) (extreme values included).
• the gas used for the implementation of the spinning of the cake is obviously a gas inert vis-à-vis the explosive charge. It may especially consist of air, nitrogen or helium. It consists advantageously of air.
• the cake drained At the end of the spin (the duration of such a spin being generally 30 min to 1 h), the cake drained generally has a mass ratio, liquid / explosive charge, between 0.5 and 2 (including extreme values). ).
• the height of said wrung cake thus containing a reduced humidity
• it is logically limited with reference to the critical detonation height of the load concerned (see above). It is usually at most 10 cm.
• the cake drained (after spinning), always arranged on the filter is disintegrated (eroded) mechanically until it is obtained, in a fluidized bed, explosive charge in granular and dry form.
• the gas is injected, in the form of at least one jet, according to two successive regimes; said at least one jet impacting (directly) the side of the wrung cake resting on the filter.
• the gas injected during this step c of the process is obviously also an inert gas vis-à-vis the explosive charge. It can also consist in particular of air, nitrogen or helium. It also advantageously consists of air.
• the same gas is advantageously used for the implementation of the steps b (spinning of the cake) and c (disintegration of the cake and obtaining of the fluidized bed) of the process of the invention.
• the at least one jet impinges (directly) the filtered cake disposed on the filter to generate, in two stages, the fluidized bed (of course above said filter).
• the gas is injected below said cake (below said filter), (directly) in contact with said cake, in two successive regimes.
• Managing the number of jets (it is generally advantageous to inject the disintegration gas and drying the cake wrung out in the form of at least two jets), the exact position, the orientation and the power of said (said) jet (s), in order to obtain the desired result, is within the reach of the skilled person.
• the expected result is advantageously obtained in 45 minutes to 2 hours. This time obviously depends on the moisture content and the apparent density of the explosive charge desired at the end of the process (density given by the size of the grains which is a function of the degree of disintegration of the cake).
• the gas is thus injected under the wrung cake (under the filter), to impact the underside of said wrung cake, in two successive regimes:
• the injected gas has adequate humidity and temperature. It has in fact been understood that said injected gas constitutes the means for removing the liquid remaining in the wrung cake. To ensure this function, said injected gas must have a lower moisture content than said wrung cake. Generally, this moisture content of the injected gas is much lower than that of said wrung cake: it is indeed generally less than 2% (by mass). As regards the temperature of the injected gas, it must be greater than its dew point temperature. It is generally between 20 and 70 ° C, preferably between 50 and 70 ° C. A higher temperature ensures drying in a shorter time.
• the temperature of the injected gas gas (disintegration and) drying
• the drying gas is thus injected dry (ie at a moisture content lower than that of the wrung cake) at a temperature which ensures efficient drying in a reasonable time.
• step c the jet (s) of gas develop (s) therefore a double action, mechanical action (disintegration (erosion), in two stages, controlled) and thermal (drying). It (s) impact (s) the wrung cake to put the explosive charge in a fluidized bed and dry (s) the elements of said disintegrating cake and finally fully disintegrated (it (s) dry) then the elements of the fluidized bed ). It (s) causes (s) almost all the liquid remaining in the cake wrung (at the end of step b), to obtain the explosive charge, granular, dry, fluidized bed.
• the entrained liquid in gaseous form and optionally in the form of droplets) is discharged with the gas (advantageously air) injected.
• step d) Injecting the jet (s) of gas being stopped, the grains of the fluidized bed are deposited, by gravity, on the filter. They are recovered there, dry. In particular, they can be recovered, containing less than 1%, and even less than 0.1%, of liquid (see above).
• the liquid recovered, during the implementation of step a (of filtration) and / or, very advantageously, and of step b (dewatering) of the process of the invention, is recovered for recycling. (for the preparation of new suspensions upstream).
• the method of the invention is suitable for treating many types of explosive charge suspensions.
• Those skilled in the art have however already understood that its implementation is a priori more difficult to treat suspensions containing explosive charges particularly sensitive to static electricity, such as hexanitrohexaazaisowurtzitane (HNIW or CL20).
• HNIW hexanitrohexaazaisowurtzitane
• the skilled person is able to manage the process parameters (with or without grounding of the device, preferably with, in which it is implemented), depending on the mass of load concerned and the sensitivity of the load in question.
• the explosive charge of the suspensions treated according to the invention may especially be chosen from the charges of 3-nitro-1,2,4-triazol-5-one (ONTA), of ammonium dinitroamide (DNA), of 2,4 , 6-triamino-1,3,5-trinitrobenzene (TATB) and trinitrotoluene (TNT). It is particularly recommended to implement the method of the invention with the suspensions described in patent applications WO 2010/31962. (DNA suspensions), WO 2006/108991 (DNA suspensions), as well as in US Pat. No. 4,894,462 (ONTA suspensions).
• ONTA 3-nitro-1,2,4-triazol-5-one
• DNA ammonium dinitroamide
• TATB 2,4 , 6-triamino-1,3,5-trinitrobenzene
• TNT trinitrotoluene
• the explosive charge suspensions treated according to the invention comprises a mixture (loads) of explosives of different kinds.
• Said liquid may especially be chosen from water, acidic aqueous solutions and organic solvents, in particular aliphatic hydrocarbons (such as alkanes (for example: hexane, heptane, octane)), halogenated aliphatic hydrocarbons (such as chlorinated aliphatic hydrocarbons).
• aliphatic hydrocarbons such as alkanes (for example: hexane, heptane, octane)
• halogenated aliphatic hydrocarbons such as chlorinated aliphatic hydrocarbons
• aromatic hydrocarbons for example: toluene and xylenes
• non-flammable hydrofluoroethers for example: 2-trifluoromethyl-3-ethoxydodecafluorohexane
• the method of the invention is perfectly suited to explosive charges insofar as it involves little mechanical stress, in fact of low mechanical stress controlled (see the direct impact of the at least one jet on the cake, according to two successive regimes, which is responsible for progressive disintegration (as specified above).
• the invention relates to a device that is particularly suitable for carrying out the method of the invention:
• Such a device comprises:
• a substantially cylindrical enclosure equipped, in its volume, at its lower part, with a filter that is suitable for filtering a suspension and thus for retaining the solid phase (dispersed) of said suspension (in the form of a cake);
• gas injection means arranged below said filter and suitable for delivering said gas in the form of at least one upward jet intended to impact the face of said retained solid phase resting on said filter; means for evacuating, from said chamber, gases arranged above said filter, said evacuation means being advantageously equipped with a particulate filter; and
• the device may further include means for permanently monitoring its electrical continuity with the earth.
• the filter in question is advantageously a metal filter, in particular a stainless steel filter (generally arranged horizontally).
• Said gas injection means are suitable for delivering said gas in the form of ascending jets, said jets impacting (directly) the face of the cake resting on the filter (this impact (direct) excludes hood and drying gas distribution chamber, as provided in the device according to DE 33 38 572).
• Said injection means are obviously suitable for injections according to the two successive regimes provided.
• the device of the invention comprises means for feeding it to the suspension to be treated. It more specifically comprises means for pouring said suspension on said filter. It is conceivable that said means comprise at least one opening (high) in the enclosure and ensure such a spill with a reasonable drop height (advantageously minimal).
• Suitable means (generally at least one opening (equipped with at least one drain)), arranged in the lower part of the chamber, must be provided to evacuate the liquid from the chamber through the filter, during filtration and spin.
• the same means are advantageously used, for the evacuation of liquid, during said filtration and said spin.
• the device comprises means for pressurizing the chamber (for the purpose of dewatering the solid phase retained on the filter).
• Said means including compressor + channel + opening of the enclosure) allow the supply of the upper part of the enclosure (above the filter) into a gas under pressure.
• it is advantageously provided to associate with said pressurizing means deflection means (deflectors).
• the device also comprises, in its upper part, gas evacuation means (mainly injected gas but also residual gaseous liquid and optionally in the form of droplets), said means advantageously comprising a particulate filter (a filter cartridge, suitable for to trap the smallest grains, extracted from the wrung cake, entrained by the gas flow).
• gas evacuation means mainly injected gas but also residual gaseous liquid and optionally in the form of droplets
• said means advantageously comprising a particulate filter (a filter cartridge, suitable for to trap the smallest grains, extracted from the wrung cake, entrained by the gas flow).
• injection of gas (hot) via the injection means allows to erode (disintegrate) the wrung cake and put the load in a fluidized bed, while drying said charge and driving the residual liquid in the gas stream (hot) to the gas discharge means, advantageously equipped with the particulate filter.
• Said injection means are suitable for injecting the gas in the form of a single jet or under the form of several jets, preferably in the form of at least two jets.
• FIGS 1A to 4 schematically show a device of the invention, at different stages of the method of the invention.
• Figures 1A and 1B illustrate the filtration step (respectively at the beginning and end of said filtration).
• the 2A and 2B illustrate the step of wringing the cake (respectively at the beginning and end of said spin).
• Figures 3A, 3B and 3C illustrate the progression of the disintegration of the wrung cake to obtain the fluidized bed ( Figure 3C).
• Figure 4 illustrates the quasi-final phase of the process (the dry charge is deposited on the filter, just before recovery).
• a device 100 comprising an enclosure 10 of substantially cylindrical shape. In the volume of said enclosure 10, in the lower part thereof, there is the filter 1. Said device 100 further comprises:
• These supply means 13 in the suspension S are hereinafter more precisely described with reference to FIG. 1A. They comprise, according to the variant shown, a pipe 13a for supplying said suspension S, a valve 13b for controlling the supply of said suspension S and an opening 13c arranged in the wall of said enclosure 10;
• liquid evacuation means 11 of said enclosure 10 Said means 11 are obviously arranged in the lower part of said enclosure 10, under the filter 1. These evacuation means are hereinafter more precisely described with reference to FIG. 1A. They comprise, according to the variant shown, an opening 11a arranged in the bottom of the enclosure 10, a drain 11c and a valve 11b. Said drain 11b is suitable for discharging the liquid L of the suspension S into a receptacle 12;
• pressurizing means 15 of said enclosure 10. These means are obviously arranged above the filter 1. They are more specifically described below with reference to Figure 2A. They are suitable for delivering the pressurizing gas G. They comprise upstream a reserve of gas G under pressure or a compressor (means not shown) and a supply line 15a of said gas G under pressure, a valve 15b for controlling the delivery of said gas G under pressure and a suitable opening 15c arranged in the wall of the enclosure 10 (for the delivery, at the wall, of said gas G under pressure or the passage of said pipe 15a ensuring the delivery of said gas G downstream of said opening 15c in the volume above filter 1). A deflector 16 associated with said pressurizing means 15 has been shown in the figures.
• each opening (14c) could correspond to a pipe equipped with a valve
• Said means 17 are hereinafter more precisely described with reference to FIG. 3A. They comprise an orifice 17c formed in the wall of the enclosure 10, a gas evacuation pipe 17a and a valve 17b. Said pipe 17a opens into the volume of the enclosure 10, according to the variant shown. It is associated with it a particulate filter 18, able to retain the smallest particles generated by the disintegration of the wrung cake 2 '.
• This filter could, according to another variant, be arranged at the wall, the pipe not penetrating into the enclosure. There is shown at 20 an opening of the enclosure 10 which allows the recovery of the dried, dried load at the end of the process.
• the device 100 is electrically connected to the earth, with permanent control ( ⁇ ) of the electrical continuity.
• FIG. 1A illustrates the beginning of the implementation of the filtration.
• the suspension S enclosing the explosive charge C in the liquid L is delivered via the pipe 13a of the supply means 13.
• the liquid L passes through the filter 1 and is recovered, via the liquid discharge means 11, into the receptacle 12
• the valves 13b and 11b are obviously open, the valves 15b and 14b are closed.
• the drying of the cake 2 is shown schematically in FIG. 2A.
• Part of the liquid L '(liquid L entrapped in the cake 2) is extracted from said cake 2 (and is recovered in the receptacle 12), under the action of the pressurizing gas G.
• the valves 13b and 17b being closed, the pressurizing gas G is delivered via the pressurizing means 15. It has been seen that the deflector 16 conveniently distributes said gas G to the upper surface 3 'of the cake 2.
• the same references 3' and 3 "have been preserved for, respectively, the upper and lower surfaces of the cake at the beginning of spinning (FIG. 2A), while spinning, at the end of spin (Figure 2B) and first disintegration phase (Figure 3A).
• the third step of the process of the invention (dual mechanical (two-step) and thermal action of gas G is then carried out on said wrung cake 2 'On the schematized variant, gas G' disintegration and drying is injected in the form of (four) jets 4 under the filter 1 (it therefore impacts (directly) the wrung cake 2 'on its lower face 3 "which rests on said filter 1), according to two successive regimes (pressure p and flow rates: d and then D (see above).)
• the injection and its effect according to the first regime are schematised in FIG. 3A, the injection and its effect according to the second regime in FIG. 3B.
• the "attack" of the integrity of the wrung cake 2 ' (direct attack by the gas jets, the gas being injected in the first regime) is diagrammatically represented, ie the appearance and growth of channels 6a in the thickness of said wring cake 2 ', growth of said channels 6a which transform them into open channels 6 (or chimneys 6).
• the eroded material circulating in said channels 6a and 6 participate in the development of erosion, especially at the upper surface 3 'of the wrung cake 2' (disintegrating) once it is out of said channels 6.
• the charges extracted from said cake 2 ', more or less dry, are suspended above said cake 2'. They constitute therein an expanding fluidized bed 5a.
• FIG. 3A the "attack" of the integrity of the wrung cake 2 '(direct attack by the gas jets, the gas being injected in the first regime) is diagrammatically represented, ie the appearance and growth of channels 6a in the thickness of said wring cake 2 ', growth of said channels 6a which transform them into
• valve 17b is open for the evacuation, on the one hand, of the injected gas G 'and, on the other hand, of the liquid L' (in the gaseous state and optionally in the form of droplets) still present in the squeezed cake 2 'at the end of the pressurization stage (the valves 13b, 15b and 11b being obviously closed).
• Charges C of smaller sizes ( ⁇ 30 ⁇ ) are not evacuated, they remain trapped in the particulate filter 18.
• step c of the process the gas supply G 'is stopped (the valve 14b is closed, the jets 4 are canceled).
• the fluidized bed 5 disappears, the charge C, in granular and dry form, is deposited on the filter 1. It can be recovered through the opening 20 of the chamber 10. This opening 20 has obviously been provided at an adequate level .
• the recovery of the dry charge C can be carried out via an airlock, a glove box, arranged on said opening 20.
• FIG. 4 shows the charge C on the filter 1 and the open opening 20 with an arrow to symbolize the step of recovering said charge C in granular and dry form.
• the ONTA crystals of the suspension had a monomodal particle size distribution, with a median diameter (D 50 ) of 200 m.
• the filter arranged in the lower part of the volume of the chamber, was a stainless steel filter which had a porosity calibrated at 150 ⁇ .
• the suspension was introduced into the chamber above the filter.
• the upper part of the chamber was then pressurized from 2xl0 5 Pa absolute (2 bar absolute) to 3xl0 5 Pa absolute (3 bar absolute) for the purpose of wringing the cake.
• the pressurization gas (air) injected at the top of the chamber was dry gas (1% (mass) moisture).
• the pressure was maintained for 1 h.
• Step c obtaining a fluidized bed of dry ONTA grains
• Step c creation of channels (chimneys) in the wrung cake
• Dry air (1% moisture) was then injected from the bottom of the chamber (by 2 injectors) at a temperature of about 60 ° C for 0.5 h. Said dry air thus impacted (directly) the side of the wrung cake resting on the filter.
• the same injection means were used to inject the same dry air (1% humidity), at the same temperature, for a further 0.5 h, at a flow rate of 100 to 200 Nm 3 / n and along a ramp pressure of 5 bar to 7 bar (5xl0 5 to 7xl0 5 Pa).
• the cake after these 0.5 hours, was completely disintegrated.
• the grains of the explosive charge were dry, levitating. They constituted, with the injected dry air, a fluidized bed.
• the water / ONTA mass ratio of the recovered dry load was 0.1%.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Drying Of Solid Materials (AREA)
• Filtering Materials (AREA)

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• 2014
  • 2014-03-28 FR FR1400760A patent/FR3019177A1/fr active Pending
• 2015
  • 2015-03-27 EP EP15717040.8A patent/EP3122706B1/de active Active
  • 2015-03-27 WO PCT/FR2015/050790 patent/WO2015145088A1/fr active Application Filing
  • 2015-03-27 US US15/129,962 patent/US9963397B2/en active Active
  • 2015-03-27 PL PL15717040T patent/PL3122706T3/pl unknown

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