Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
  • A62D3/37—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by reduction, e.g. hydrogenation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
  • B01J3/008—Processes carried out under supercritical conditions
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/06—Treatment of sludge; Devices therefor by oxidation
  • C02F11/08—Wet air oxidation
  • C02F11/086—Wet air oxidation in the supercritical state
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/24—Organic substances containing heavy metals
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/28—Organic substances containing oxygen, sulfur, selenium or tellurium, i.e. chalcogen
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S208/00—Mineral oils: processes and products
  • Y10S208/952—Solid feed treatment under supercritical conditions

Definitions

• the present invention relates generally to a process for transforming complex chemical structures in a supercritical fluid.
• complex chemical structure is understood to mean any chemical structure, that is to say any association of atoms or molecules, which can be either solid, liquid or gaseous.
• the complex chemical structure can be either organic in nature such as for example heavy oils or aromatic compounds, or inorganic or inorganic in nature such as for example nitrates, metal acetates, hydroxide sludges, etc.
• the transformation can concern either a single chemical structure or a combination of complex chemical structures.
• a synergistic effect can be implemented, one of the complex chemical structures being able to act as a catalyst vis-à-vis the other (or its degradation products).
• the invention finds applications in a wide variety of fields. It can be applied for example to the modification of molecular structures in molecular engineering or pharmacology. It can also be applied to the degradation of industrial effluents, for example the degradation of de-inking sludge or slurry of metal hydroxides. The invention can also be applied to the destruction of explosives or dangerous products, such as for example PCBs (polychlorinated biphenyls). Yet another area may be product recycling natural such as, for example, manure, cellar effluents and those from milk processing.
• Oxidative treatments in supercritical medium - mainly in water - have been studied and developed. Mention may be made on this subject of document (1) WO-A-81/00855 which relates to the treatment of organic materials in supercritical water. The products obtained during this treatment are essentially carbon monoxide and dioxide. This document also provides for the use of hydrogen sensor metals (Ni, Mo, Co, Pd, Pt) and their oxides, as catalysts for the treatment.
• the exothermic nature of the reactions involved in the oxidative treatments is, in known manner, used to advantage in the maintenance, at least partial of the treatment process. This is the case in particular when the treatment is carried out with supercritical water whose critical temperature is close to 374 ° C.
• Treatments other than treatments involving oxidation in a supercritical medium are known, for example, from document EP-A-0 157 339 which describes a process making it possible to prepare hydrocarbons, preferably saturated, from sludge from treatment plants having a water content of 70 to 98.5%, by treatment of this sludge at a temperature of 300 to 600 ° C and at a pressure of 100 to 500 bars.
• This method includes the steps of determining the concentration of nitrates and nitrites present in an effluent, inducing in this effluent the presence of formate as a nitrates and nitrites reducer, heating the mixture to a temperature of 200 to 600 ° C and at a pressure sufficient to maintain the liquid effluent in a monophasic range, either liquid or supercritical, for a sufficient residence time to reduce the content of nitrates and nitrites and give essentially nitrogen, carbon dioxide, and carbonates and bicarbonates.
• An object of the present invention is to propose very generally a process for transforming chemical structures which does not have the drawbacks and limitations of the processes mentioned above.
• Another object of the present invention is to provide a process for transforming chemical structures which results directly, either in recoverable products, or in products whose characteristics comply with standards for discharge into the natural environment.
• Yet another object of the present invention is a transformation of chemical structures which does not subject the enclosures and treatment devices to a corrosive action, or which at least limits such a corrosive action.
• Another object of the present invention is a process which uses neither molecular hydrogen nor catalyst, and which allows, thanks to the control of parameters such as temperature, pressure and chemical parameters, to control and direct at will the reactions and transformations occurring in the supercritical domain of the fluid or reaction medium in order to obtain at will the desired recoverable products .
• the invention relates more precisely to a process for the chemical transformation of at least one complex chemical structure into at least one final product, characterized in that the chemical transformation comprises at least one reduction reaction in a solvent at l 'supercritical state.
• the objective of the invention is to promote, through controlled chemical reactions, the degradation of effluents, molecules or complex chemical structures, at least one of the stages of these chemical reactions being a reduction.
• the chemical transformation is understood to mean both the degradation of the molecular (or atomic) structure of the complex chemical structure (s), into one or more chemical structures with a simpler molecular structure, and the chemical interaction of the molecular structures more or less complex, with each other, or with the solvent in the supercritical state.
• the chemical interaction of molecular buildings results in a set of reactions or solubilizations of which one or more are reductions.
• reduction phenomenon is understood to mean any reaction leading, for one of the elements of the chemical structure to be degraded, to a gain of electrons.
• the solvent can be water, an alcohol such as ethanol, a water-alcohol mixture, or any other suitable solvent. Its choice depends essentially on the chemical structures that one wishes to transform. In addition, by relying on the one hand on the specific physicochemical properties of supercritical fluids and, on the other hand, on the reducing conditions making it possible to save certain functions for the final products resulting from the transformation, it is possible according to the structures to be treated simply result in degradation, or in the formation of recoverable compounds, as appears in the following description.
• a specific reducing additive is not essential during the formation of the reaction fluid.
• Step a) then boils down to the formation of a reaction fluid comprising at least the complex chemical structure (s) in solution or in suspension in the solvent, the solvent and / or the at least one of the chemical structures of the reaction fluid having, under the supercritical pressure and temperature conditions of the solvent, a reducing character.
• Step a) of the process then comprises the formation of a reaction fluid comprising the complex chemical structure (s) to be treated in solution or in suspension in the solvent, with at least one complex chemical structures or the solvent transforming under supercritical condition into a compound having a reducing character.
• a reaction fluid comprising the complex chemical structure (s) to be treated in solution or in suspension in the solvent, with at least one complex chemical structures or the solvent transforming under supercritical condition into a compound having a reducing character.
• the supercritical conditioning essentially consists in increasing the pressure and the temperature of the reaction medium to values at least higher than the critical pressure and the critical temperature of the solvent.
• reaction fluid generally comprises from 1 to 20% by mass of complex chemical structures to be transformed.
• the reductive transformation can be described in terms of the hydrogen equivalents necessary to obtain, during the latter, the targeted final products.
• the present inventors have demonstrated that the supercritical domain of the reaction medium or fluid could schematically and globally be divided into at least three major domains or zones which we will call in this which follows domain A, domain B and finally domain C.
• domain A is a domain in which low temperatures and high pressure prevail, that is to say that the pressure is a pressure greater than the critical pressure of the reaction medium or fluid and is most suitable for the solubilization (in solution) of the complex chemical products and / or structures present in the complex system or mixture or reaction medium or fluid, while the temperature is the lowest possible temperature which allows to be in the supercritical domain of the complex system or mixture, or reaction medium or fluid.
• the fluid has a density close to that of the liquid phase. The solubility of complex chemical structures is therefore greatly facilitated in this area.
• domain B is a domain of high temperatures, that is to say that the temperature is a temperature higher than the critical temperature of the reaction medium and is the most suitable for the degradation of chemical products and / or structures complexes found in the reaction medium or fluid, while the pressure is the lowest possible pressure which makes it possible to be in the supercritical domain of the complex system or mixture or reaction medium or fluid.
• the fluid has a much lower density.
• the solubility of complex chemical structures is reduced, but on the other hand, the degradation and / or cleavage reactions are more important.
• domain C is an intermediate domain where the temperatures and pressures are intermediate or complementary to those defined for domains A and B defined below. That is to say that there occurs in this area both a solubilization of complex structures, and a degradation of these structures and, there can be achieved an optimization between solubility and thermal degradation.
• the document EP-A-0 157 339 comprises a hydrogenation by molecular hydrogen and is limited specifically to sludge from a purification station, this which is restrictive in relation to the above objectives.
• the present process controls the pressure and temperature conditions in one domain, or following a cycle, in the exclusively supercritical domain of the fluid or reaction medium, which promotes the targeted chemical reactions. Everything is done to use all the hydrogen in atomic form available in the reaction fluid. If necessary, a supply is made via hydrogenated additives for which the bonding energy between the hydrogen and the atom to which it is bonded is weaker than the bonding energy between the hydrogen atoms in molecular hydrogen. The ace. allows you to manage this addition. In these conditions, the use of catalysts is not necessary.
• parameters characteristic of the chemical conditions of the medium namely essentially the value of the ace. able to control the reduction step, pH value, etc.
• residence times in the supercritical field of the reaction medium are obtained which are much shorter than in the prior art, the residence time is effect most of the time less than or equal to 10 minutes (for example between 1 and 5 minutes) and can even reach one or a few seconds or even less (1/10 or 1/100 of a second). Therefore, there occurs in the process according to the invention less, or almost not, more or less uncontrollable intermediate reactions which lead to end products which are not desired.
• the chemistry of the process is, according to the invention, perfectly controlled, controlled and controlled by the parameters indicated above, in particular by the temperature and the pressure which make it possible to adjust and optimize the reaction speed.
• the kinetics of the reaction are thus increased by acting solely on the temperature and the pressure without the need to add a catalyst, which is mandatory in the prior art. If one acts more on the ace.H for example by increasing it, thanks in particular to the addition of a hydride such as NaBH 4 , it is possible to carry out an additional orientation of the chemical reactions and direct reactions to the production of specific products.
• a catalyst such as NaBH 4
• - Figure 1 is a diagram schematically illustrating an implementation of a chemical transformation process according to the invention
• - Figure 2 is a diagram showing on the ordinate the amount of gas (expressed in arbitrary units) produced during of a chemical transformation according to the invention as a function of the time counted from the placing in supercritical condition of the reaction medium. Presentation of experimental examples of implementation of the invention
• FIG 1 shows both the main steps of the process and their chronological sequence.
• a double arrow with the reference 1 designates the constitution of a reaction medium adapted to the optimization of the reduction (transformation) of at least one complex chemical structure.
• a reactor 10 is supplied respectively by lines 12, 14, 16 and 18 with one or more complex chemical structures 20, a solvent 22 and possibly one or more additives 24.
• the chemical structure (s) to be transformed can be dissolved or suspended in the solvent, in reactor 10, which corresponds to lines 12 and 14. It is also possible that the chemical structures are already initially in suspension or in solution in a liquid phase which constitutes the solvent, which corresponds to line 12 (and possibly 16) when the term solvent is extended to the concept of complex chemical structure. For example, when it is desired to treat deinking sludges, these include cellulose and suspended inks in water. Cellulose and inks are thus the complex chemical structures to be transformed and water the solvent, the quantity of which can be controlled. The chemical structure-solvent mixture is in this case carried out prior to its introduction into the reactor (line 14).
• references 28 and 30 designate the recovery and analysis of the transformation products.
• the recovered products are then separated into recoverable products 32
• the double arrow 5 distinguishes the field of process control.
• the control of the composition which bears the general reference 36 is carried out according to the analysis 38 of the products resulting from the transformation.
• Arrows 40, 42, 43 denote an initial adjustment of the composition of the reaction fluid, that is to say of the mixture of chemical structures-solvent-reducing additive (possibly).
• the adjustment of the composition of the reaction fluid is carried out in order to have an ace.H. sufficient.
• a check consists in checking the pH and / or the ace. reaction fluid.
• This control bears the references 46 and 48. It may be noted on this subject that the adjustment of the pH and / or the ace.H. in 46 and 48 can take place essentially by acting on the supply of additive to reactor 10, but it can also relate to the supply of chemical structures or in solvent. In particular, one or more additives controlling respectively the reducing nature, the pH or a. eH can be dosed.
• a.ce.H. can be defined as the chemical contribution in hydrogen equivalents to transform all the carbon into CH4 under the conditions of the experiment and taking into account the hydrogen equivalents already present in the initial complex structure.
• This chemical contribution in hydrogen equivalents can for example be defined in milligrams of reducing additive per gram of initial material.
• the reducing agent does not contain hydrogen, one must take into account its ability to capture oxygen in such a way as to keep the ratio
• one of the complex structures, or one of the products resulting from the degradation of one of these can serve as a catalyst for obtaining targeted end products.
• Table I refers to a first example of experimental implementation of the invention in which approximately 30 to 125 ml of reaction fluid with a pH equal to 7 containing in suspension 3 to 5% by mass of sludge of a deinking cell having treated magazines (colored inks) are treated under various conditions of pressures (30 ⁇ P ⁇ 90 MPa) and temperature (500 ⁇ T ⁇ 600 ° C) within a 150cm sealed reaction vessel * - 1 .
• the quantity of reaction fluid introduced into the enclosure then makes it possible to govern, for a given temperature, the final pressure according to its own thermal expansion value.
• Table I gives the evolution of the solubilization conditions of the sludge as a function of the treatment parameters (pressure P and temperature T).
• the treatment time (duration of the stage where P and T have constant values) is equal to 5 minutes. It is noted that the solubility increases when the pressure decreases. On the other hand, the quantity of gas produced is too small to be collected and analyzed regardless of the pH value (acid, neutral or basic).
• reaction fluid containing very black sludge in suspension coming from deinking cells from old newspaper papers (that is to say with a traditional ink heavily loaded with carbonaceous materials) are placed in a reaction chamber of approximately 150 ml.
• the pressure and temperature parameters are adjusted as a function of the ratio between the volume of liquid phase introduced and that of the reaction chamber. In particular when the temperature is close to 600 ° C., the pressure is of the order of 60 MPa.
• the duration of treatment is changed from 3 to 30 and then to 60 minutes.
• the pH of the solution passes after transformation to 8.
• a substantially similar volume of gas is collected after reaction in the three cases (3, 30 and 60 min, at 600 ° C. and 600 bar ( 60MPa)).
• a fourth experimental example shows the influence on the results of the pH of the reaction medium before treatment.
• Table III summarizes on this subject the results of a test where, as in the third example 55 ml of a reaction fluid containing in suspension very black sludge from deinking cells of old newsprint are placed in an enclosure reaction of a volume close to 150ml. The corresponding amount of dry matter relative to the liquid phase is approximately 3 to 5%. The temperature is kept constant (600 ° C) as well as the duration of the treatment which is 3 minutes. Several experiments are carried out at variable pressure (from 60 to 100 MPa) and for various pH values (4, 7, 13) without adding a reducing additive.
• pH ⁇ 7 a substantially neutral value (pH ⁇ 7) before treatment, for example by adding either a basic additive such as sodium hydroxide, or an acid such as hydrochloric acid for example.
• EXAMPLE 5 A fifth example of implementation of the invention relates to the treatment of an effluent such as a hydrocarbon.
• Table V below specifies the experimental conditions used, as well as the main results observed. Reading Table V below shows that the increase in pressure tends to promote the degradation of the oil as well as the formation of gas. This results in particular from the comparison of experiments B2 and Bg.
• the addition of an additive (lithium borohydride) giving the reaction fluid a reducing character also makes it possible to reduce the pressure at which the treatment is carried out, as experiment B7 shows.
• a reducing additive such as LiBH4 was added in proportions of approximately 0.5 g per 50 ml of reaction fluid. The addition of the additive also leads to almost complete degradation of the oil and to greater gas production.
• Figure 2 attached is a diagram obtained by a chromatographic analysis and illustrates the influence of the reducing additive on the evolution of gas.
• This example concerns slurries of metallic hydroxides and shows that it is also possible in this case to evaluate the role of the various parameters.
• Example 7 To the mixture of complex chemical structures identical to that treated in Example 7 is added 0.1 g of sodium borohydride per 19 g of initial material and 50 cm 3 of water. The whole is treated for 5 minutes at a temperature of 600 ° C. and a pressure of 900 bar. After returning to normal conditions of the assembly, an increase in the volume of the gas phase consisting of light hydrocarbons is observed, showing the role of the chemical contribution in hydrogen equivalents. A liquid phase containing carbon in suspension is also extracted from the reactor. The mass of carbon is of the order of lg. EXAMPLE 9 50cro.3 of ethanol is introduced into a 150c ⁇ .3 reactor made of an alloy based on nickel-cobalt. The reactor is brought to a temperature of 600 ° C.
• This example relates to an association of complex chemical structures of the casein type.
• the mixture is then brought to a temperature of 600 ° C., the pressure reached being of the order of 850 bar. After a 10-minute plateau, the assembly is returned to normal conditions.
• EXAMPLE 12 This example relates to an association of complex chemical structures derived from milk and known as whey. We take 50 c ⁇ .3 of whey and 0.1g of NaHB4 (sodium borohydride). The whole is brought to a temperature of 600 ° C., the pressure reached being of the order of 750 bar. After such a treatment lasting 15 minutes, the assembly is returned to normal conditions.
• NaHB4 sodium borohydride
• Examples 13 to 15 provided below have, on the basis of initial products identical to those mentioned in document EP-A-0 157 339 (biological sludge), the objectives of testing with and without contribution of a.ce.H.) their degradation in the fields A, B, C above.
• reaction fluid therefore consists of water at a pH of 7 with 1% by mass of biological mud in suspension.
• Methane is the majority (of the order of 56%), the other constituents being ethane (approximately 17%), propane (approximately 12.5%) and unsaturated hydrocarbons of ethylene or acetylene type in the state of traces (about 0.8%).
• 14b The addition of 0.6 g of NaBH., To the reaction fluid leads after treatment under the same conditions as in 14a to an even more complete degradation of the mud, which corresponds to the maximum degradation obtained for the series d 'tests 13a, 13b, 14a, 14b (clarification of the liquid phase and disappearance of solid particles). The recovery of a greater volume of gas is observed compared to Example 14a.
• the analyzes of the various phases have shown the presence of C5 to C8 hydrocarbons in the liquid and methane, ethylene, acetylene, ethane, propane, butane, isobutane within the gas phase. Methane is in the majority and its presence increases substantially (71%) compared to 14a (56%). The percentage of ethane is also increasing (around 20%).
• the signs -, +, ++, +++ respectively designate a presence too weak for the analysis of a given product, a weak presence, an average presence and a strong presence of the product.
• the signs -, +, ++, +++ respectively designate a presence too weak for the analysis of a given product, a weak presence, an average presence and a strong presence of the product.

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• Organic Chemistry (AREA)
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• 1994
  • 1994-12-06 FR FR9414664A patent/FR2727634A1/fr active Granted
• 1995
  • 1995-12-05 EP EP95941765A patent/EP0796143B1/fr not_active Expired - Lifetime
  • 1995-12-05 DK DK95941765T patent/DK0796143T3/da active
  • 1995-12-05 US US08/849,265 patent/US5914031A/en not_active Expired - Fee Related
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