Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – With means applying electromagnetic wave energy or...
Reexamination Certificate
2001-01-09
2003-12-02
Seidleck, James J. (Department: 1711)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
With means applying electromagnetic wave energy or...
C210S177000
Reexamination Certificate
active
06656436
ABSTRACT:
The present invention concerns a system for converting chemical structures, that is to say a system to produce chemical reactions in a fluid under pressure and at temperature, in particular a supercritical fluid, in which said fluid contains a solvent and at least one salt and is subjected to ultrasound action.
The area of the invention, may, in general, be defined as the area of chemical conversions, produced in a fluid medium under pressure and at temperature, in particular in a supercritical medium. Supercritical fluids in particular offer the advantage of providing better control over the conversion process, since a single phase system is used contrary to most conventional processes which use poly-phase systems.
Most of the processes carried out in a fluid medium under pressure and at temperature, in particular in a supercritical medium, have the disadvantage, in order to properly conduct the conversions and reactions, of requiring the addition to the supercritical medium of various reagents, additives and active species, most of the time brought from outside the chamber in which the reaction takes place in a medium under pressure and at temperature, in particular in a supercritical medium. The addition of tease compounds often requires voluminous costly devices which, in addition, do not allow homogeneous distribution of the reagents and other products within the reactor under pressure and at temperature, supercritical in particular, and therefore do not provide optimal control over the reactions. This is the case in particular in processes in which oxidation of substances is carried out in an aqueous medium in which the air, required for the reaction, is collected at atmospheric pressure, is then compressed and finally injected into the medium. The compression of air requires large-scale installations and accounts for a major part of the high expense of the process. Also, the oxygen added is in molecular form and it is known that the latter is distinctly less active than oxygen in atomic form.
Numerous other oxidizing treatments in a fluid medium under pressure and temperature and in particular in a supercritical medium—chiefly in water—have been researched and developed. In this respect document WO-A-81/00855 may be cited which concerns the treatment of organic materials in supercritical water. The products obtained during this treatment are essentially carbon monoxide and dioxide. This document provides for the use of hydrogen capturing metals (Ni, Mo, Co, Pd, Pt) and their oxides as catalysts for the treatment. These catalysts, once again must be added from outside the supercritical reactor with the resulting disadvantages.
Treatments, other than treatments which use oxidation in a supercritical ,medium, are known, for example from document EP-A-0 157 339, which describes a process with which it is possible to prepare hydrocarbons, preferably saturated, from the sludge derived from treatment plants having a water content of 80 to 98.5% by treating this sludge at a temperature of 300 to 600° C. and at a pressure of 10 to 50 MPa (100 to 500 bars). The sludge, immediately after this treatment at high temperature and pressure, or simultaneously with this treatment, undergoes hydrogenation with the addition of molecular hydrogen, necessarily in the presence of a catalyst. Here again the same problems arise as those mentioned above concerning the addition of outside additives to the medium, and the low reactivity of hydrogen, as previously for molecular oxygen, requiring the necessary presence of an additional catalyst.
Document U.S. Pat. No. 5,118,447 concerns a process for the denitrification of nitrogen-containing compounds, in particular of nitrates and nitrites present in numerous industrial aqueous wastes derived for example from the chemical industry, from surface treatment industries, from explosives and ammunition industries.
In this process, it is again necessary to add formates to the medium to act as reducers of the nitrates and nitrites, before entering the supercritical domain.
In order to overcome the above-mentioned problems, that is to say to overcome the need for voluminous costly devices for reagents and additives, and in order to obtain a homogeneous, uniform reaction throughout the whole volume of the reactor, and to generate more efficient active species, without a catalyst, processes have been researched and developed in which the additive, the reagent, or the essential active species are generated in situ by electrochemical means in a supercritical medium.
Hence, document U.S. Pat. No. 4,581,105 relates to an electrochemical cell containing an aqueous electrolyte in the supercritical state. The electrolyte contains at least one species called an “electroactive species” which, when a current is applied to the electrodes, reacts to give “electrochemical products” that are soluble in the supercritical fluid.
In the anode and cathode compartments, oxygen and hydrogen may for example be generated.
Document EP-A-0 535 320 concerns a process and an oxidation device for inorganic and organic substances, in particular for aqueous waste, in which the waste is treated in a supercritical reactor containing an electrolysis zone to generate oxygen.
The process and devices, which generate active species by electrolysis in a supercritical medium, must be used on waste which already has sufficient conductivity, therefore with a high salt content, or in which considerable quantities of salts are added to give them suitably high conductivity. The same problems occur as with the processes and devices described above concerning the addition of additives. Moreover, the presence of salts in high concentration causes major precipitation and corrosion problems in supercritical reactors and in the entire installation.
In addition, electrolysis requires complex devices and finally generates reactive species whose reactivity is still not sufficient in a great number of cases.
The use of ultrasonics to produce reactions in fluids under pressure and at temperature has also been put forward in the literature.
Document U.S. Pat. No. 4,793,919, for example, concerns a process and equipment for the oxidation of aqueous suspensions of organic matter at high temperature and pressure in the presence of an oxidizing gas. The equipment comprises a reactor equipped with a static mixer in which the aqueous suspension to be treated circulates, and the oxidizing gas is added to the suspension. According to one particular embodiment of the equipment, ultrasound may be used to increase the oxidation reaction by breaking down the organic matter already partially oxidized and by causing the air bubbles to burst.
For this purpose, an ultrasound probe may be provided in the upper part of the reactor. Ultrasound may also be used in a configuration with several reactors in which, at the outlet of the static mixer, organic molecules which are broken down undergo further oxidation in a reactor located downstream. The type of reactors used is not specified.
This document specifically concerns an oxidation treatment which again involves the addition, from outside, of an additional reagent, namely an oxidizing gas. The same problems are faced therefore as those already mentioned above.
Document EP-A-0 832 852 describes a destruction process, by oxidation, of harmful substances in household waste waters, waters from industrial processes and drinking waters by means of persulphate at a temperature greater than 130° C. and under a pressure of more than 1 bar, for example 5 to 6 bars.
The reagents used and their proportions are detailed in claims 2 to 8 of this document, the oxidizing agent used may also contain hydrogen peroxide.
A base detergent, such as milk of lime, may be added to the treated water to maintain the pH, and it is also possible to use a catalyst.
It is also indicated in this document that ultrasonics may be used, but no range of frequency is mentioned.
This process and this device necessarily require the addition to the reactor of at least one reagent, in particular an oxidizing reagent, w
Aymonier Cyril
Berdeu Bernard
Cansell François
Sentagnes Dominique
L'Electrolyse
Seidleck James J.
Tran Thao
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