BE834245A - WALL REACTOR PROTECTED BY A FLUID, FOR CHEMICAL REACTIONS AT HIGH TEMPERATURE - Google Patents

Description

       

  Reactor with wall protected by a fluid, for chemical reactions

  
high temperature.

  
The present invention relates to wall reactors. protected by a fluid intended for carrying out chemical reactions at high temperature, as well as various processes which can be carried out in these reactors and which could not be carried out in practice until now or

  
which were considered theoretically possible only.

  
The fluid wall reactor and the processes involved

  
  <EMI ID = 1.1>

  
heat, the reaction media envisaged being isolated in an envelope of protective fluid, out of contact

  
  <EMI ID = 2.1>

  
practically the radiant heater and

  
the reaction zone delimiting a cavity constituting a "black body". In the present specification, the expression "black body" generally designates a space practically closed by one or more surfaces and from which no radiation can escape in an ideal case. In the case of the reactor

  
of the invention, the thermal shield forms the surface or surfaces which delimit the black body, and the material forming the thermal shield is an insulator, prevents heat transfer from within the black body, and must be able to withstand temperatures created by the radiative coupled heat source.

  
High temperature reactors are currently used for reactions of pyrolysis, thermoclysis, dissociation, decomposition and combustion of organic and inorganic compounds. Almost all reactors in this

  
  <EMI ID = 3.1>

  
conduction, but this characteristic poses two problems

  
which limit the nature and scope of the reactions implemented. These problems are due to the fact that, in a conventional reactor which transfers heat to the reactants by convection, the highest temperature in the system necessarily prevails at the interface of the inner wall of the reactor and the reactant stream.

  
The first problem is posed by the limitation

  
available reaction temperatures dictated by the strength of known reactor wall materials at elevated temperature. The decreasing suitability of these subjects

  
to maintain their integrity when the crott temperature is obviously well known. However, since these materials must be heated in order for thermal energy to be transferred to the reactant stream, the available reaction temperatures are limited by the temperature to safely heat the reactor wall. This factor is especially important when the expected reaction. must take place at high pressure or create high pressures.

  
The second problem is due to the fact that the wall of a conventional reactor is at the highest temperature in the system and the fact that heat transfer by convection and conduction requires contact between the wall and the stream of reactants. As it is at high temperature, the reactor wall is an ideal reaction site otherwise the

  
more desirable and in many cases the products of

  
the reaction accumulates on this wall. As a result, the device can no longer transfer heat to the reagents

  
and this increasing thermal impedance necessitates the gradual increase in the temperature of the source so that

  
the initial heat transfer to the reactant stream is maintained. Obviously, as the buildup of material progresses, the temperature required for the source exceeds that which the wall material can withstand. Also, as more energy is needed for the maintenance of the reaction, the process becomes less

  
  <EMI ID = 4.1>

  
material or profitability, the installation must be stopped and cleaned.

  
Usually, cleaning is carried out mechanically by scraping the wall or chemically by combustion of the deposits. In some continuous processes, attempts have been made to scrape the wall while the reaction is in progress. However, the scraping tool itself necessarily heats up, becomes a reaction site and therefore must be cleaned afterwards. In any case, this downtime represents a significant economic loss. In many cases, a second device is fitted so that the time lost in production is minimal. However, this additional equipment generally represents a significant investment. Such high temperature chemical reactors include a tube heated to a temperature at which the internal walls emit sufficient radiation for the reaction to be initiated and sustained.

   However, as in the case of conduction and convection reactors, in reactions forming solid products the product often accumulates undesirably on the walls of the tube so that heat transfer is reduced and the tube may even collapse. butcher.

  
The reactor described in United States Patent No. 2,926,073 is intended for the manufacture of carbon black and hydrogen by pyrolysis of natural gas. The process is given as continuous but in practice, the heat transfer by convection used during the operation of the reactor poses significant problems for the maintenance and the regulation of the reaction. Since the heated reactor tubes are ideal sites for the reaction, the

  
  <EMI ID = 5.1>

  
the same. However, the problem of thermal runaway is much more important because it can cause explosions. Under these conditions, it is determined that, during the pyrolysis of natural gas, the thermal conductivity of the gas phase suddenly increases by a factor of between 5 and
30, depending on the composition of the gas. As the temperature in a conventional convection reactor cannot be regulated with sufficient precision and speed to compensate for the phenomenon, the apparatus becomes unstable in some cases and may even explode. These conditions arise in the case of conventional reactors and a solution to this problem has not yet been found.

  
US Pat. No. 3,565,766 describes a recent attempt to increase the quality.

  
charcoal by pyrolysis. The apparatus described comprises a series of hollow steel reactors forming multistage fluidized beds at progressively increasing temperatures up to about 870 [deg.] C. Fluidization at low temperatures is provided by an inert gas which can itself transmit heat, although external heating

  
  <EMI ID = 6.1>

  
produced by the overhead gas of the final stage and, in this last stage, the temperature is maintained by internal combustion of the carbonized materials in air or oxygen.

  
As this device is essentially based on heat transfer by convection, it has many defects and drawbacks described above.

  
The carbon black manufacturing apparatus disclosed in US Pat. No. 2,062,358 comprises a porous tube placed in a heating chamber.

  
Hot gas is directed from a remote furnace to the chamber, then forced through the wall of the porous tube to mix with the reactants. Thus, only the heat transfer by making a fluid to the reactants is used.

  
Given the absence of a cavity forming a black body.

  
  <EMI ID = 7.1>

  
me of fluid in the heating chamber to compensate for heat loss.

  
United States Patent No. 2,769,772 describes a reactor for the heat treatment of fluid materials such as hydrocarbons, comprising two concentric tubes placed in a furnace heated by a flame. The reagents circulate axially in the concentric permeable inner tube. A gas constituting a gaseous vehicle

  
  <EMI ID = 8.1>

  
triques and it is heated by contact with the outer wall. Fluids in the inner tube are heated by convection as the gaseous vehicle passes through the permeable wall

  
and mixes with them. Radiative transfer is expressly avoided. In fact, the inner tube cannot be heated without simultaneously heating the outer tube to at least as high a temperature.

  
The surface combustion cracking furnace described in the patent of the United States of America n [deg.] 2,436,282 uses the principle of a gaseous vehicle for heat transfer by convection similar to that of the aforementioned patent. <EMI ID = 9.1>

  
surrounded by a double envelope. A combustible fluid from an annular chamber is forced through the porous wall into the interior of the tube and is ignited. However, it is evident that the combustible fluid in the annular chamber explodes unless it is forced through the porous wall at a rate greater than the rate of propagation of the flame through the wall. Similarly, the temperature in the annular chamber must be kept below the ignition temperature of the gas-air mixture. The combustion products of the surface flame mix with the reactants in the furnace with dilution and possibly reaction with them. Heat is applied

  
  <EMI ID = 10.1>

  
bustion and reagents.

  
U.S. Patents Nos. 2,670,272, 2,670,275, 2,750,260, 2,915,367, 2,957,753 and 3,499,730 describe combustion chambers for the preparation of titanium dioxide for pigments, by combustion of titanium tetrachloride in oxygen. In patent no. 2,670,275 which is representative of this group, titanium tetrachloride is burned in a porous refractory tube. An inert gas constantly diffuses through the porous tube and enters

  
the combustion chamber where it forms a protective envelope for the internal face of the tube. This porous envelope significantly reduces the tendency of the geese parts to dioxide

  
of titanium to adhere to the walls of the reactor. As the combustion of titanium tetrachloride is exothermic, no care is taken for the transfer of heat to the reaction mixture as it passes through the tube. In reality, this patent indicates that it is advantageous to remove heat from the chamber either by exposing the assembly comprising the porous tube to the atmosphere, or by circulating a cooling fluid in a coil placed in the vicinity. of the porous tube.

  
During a chemical reaction at high temperature according to the invention, an annular envelope of an inert fluid practically transparent to radiation is formed.

  
and it has a significant axial length. Then, at least one reagent passes through the center of the envelope along a predetermined path which substantially coincides with the axis of the envelope, the reagents being confined therein. When the flow of reactants has started, very intense radiation is transmitted through the envelope so that it coincides with at least part of the path of the reactants. A sufficient quantity of rediations is absorbed in the central part so that the temperature of the reagents reaches the value necessary to initiate the desired chemical reaction.

  
When the reagents are themselves transparent to radiation, absorbent material is introduced into the reagent stream. This material absorbs a sufficient quantity of radiation so that the temperature in the central part reaches the desired value. However, in some cases, although the reagents are transparent to

  
  <EMI ID = 11.1>

  
be absorbent; in this case, once the reaction is initiated, the external absorbent material can be removed and the reaction continues. An example of such a reaction is the pyrolysis of methane to carbon and hydrogen.

  
Some reactions are partially or completely reversed when the reaction products are not immediately and rapidly cooled. In this case, the invention also relates to cooling the reaction products and the remaining absorbent materials so that undesirable chemical reactions cannot take place immediately after the end of the desired reaction.

  
The high temperature reactors with a wall protected by a fluid according to the invention transfer practically all of the heat necessary for the reactants by radiative coupling. In some embodiments, the reactor includes a tube having an inlet end and

  
an outlet end and the interior delimits a chamber. A device for introducing an inert fluid into the chamber forms a protective envelope for the inner radial surface of the tube. A device for introducing a reagent at least into the chamber through the inlet end directs the reagents along a predetermined path axially to the tube. The envelope of inert fluid confines the reactants substantially in the center of the chamber out of contact with the tube forming the reactor. Very intense radiation is created and directed into the chamber so that it coincides with at least part of the path of the reagents, with sufficient radiation being absorbed so that the temperature

  
  <EMI ID = 12.1>

  
of the desired chemical reaction. In another embodiment, the reactor comprises a tube having an inlet end and an outlet end, at least one part

  
from inside the tube forming a reaction zone. The tube is of a fabric of fibrous refractory material capable of emitting a sufficient quantity of radiation so that the temperature of the reagents in the reaction zone reaches a value allowing the initiation and maintenance of the desired chemical reaction. The fabric comprises numerous pores the diameter of which allows a uniform flow of a fluid sufficiently inert and substantially transparent to radiation passing through the wall of the tube to provide a protective envelope for the inner surface of the tube.

  
  <EMI ID = 13.1>

  
a chamber of inert fluid under pressure between the tube and the container, the inlet and outlet ends of the tube cooperating in leaktight manner with the pressure chamber. The pressure vessel has at least one inert fluid inlet which enters the pressure chamber and passes through the porous wall of the tube to the reaction chamber. The reactor further comprises a device for introducing at least one reagent into the reaction zone at the inlet end of the tube. Then the reagents are directed along a path

  
  <EMI ID = 14.1>

  
protective film so that they remain practically in the center in the reaction zone out of contact with the inner wall of the tube. An electric heating element is placed in the pressure chamber, at a certain radial distance from the tube to the outside so that it heats the tube to a temperature at which it emits enough radiation so that the desired chemical reaction is initiated and sustained. Radiation is directed into the reaction zone substantially coincident with at least part of the reactant path. A thermal shield or shield is placed in the pressure vessel and substantially surrounds the heating elements and the reaction zone so that it defines a cavity forming a black body.

  
The shielding reflects the radiation inwards, towards the reaction zone.

  
Unlike conventional convection reactors, the invention uses radiative coupling for the transfer of heat to the stream of reactants. The amount of heat transferred is independent of the physical contact between the

  
  <EMI ID = 15.1>

  
turbulent in the current. The essential consideration for heat transfer in the apparatus of the invention is

  
  <EMI ID = 16.1>

  
The inert fluid for protecting the wall of the reactor is advantageously practically transparent to radiation so that it has a very low coefficient. In this way, the radiation can be transferred through the inert fluid to the stream of the reactants with little or no energy losses. Ideally, the reagents themselves or an associated absorbent material exhibit a coefficient

  
  <EMI ID = 17.1>

  
the reagents can be finely divided (for example in a mist) so that the radiation is absorbed by trapping between the particles. As materials which absorb radiation well are generally good emitters

  
radiation, when the reagents or the associated absorbent materials are brought to a sufficiently high temperature, they form secondary radiators which re-emit energy throughout the reaction volume and therefore increase the heat transfer characteristics of the installation. This phenomenon occurs almost instantaneously and can be adjusted precisely and quickly. In addition, the re-emission phenomenon ensuring rapid and uniform heating of the reactants is completely independent of the turbulent mixing in the reactant stream.

  
The high temperature chemical apparatus and process allow the resolution of extremely troublesome problems and thus the performance of reactions which heretofore were impossible or possible only in theory. Since heat is transmitted by radiative coupling and not by convection and / or conduction, the temperature of the reactant stream may be independent of both the wall temperature and the condition of the reactant stream, and the important problem posed is by the mechanical strength of materials is solved.

   Two embodiments of the reactor according to the invention are such that the wall of the reactor is in reality cooled; two other embodiments are such that, although a wall is heated and forms a source of radiation, that wall does not experience the high pressures which are normally present when carrying out many types of reactions. For this reason, refractories such as carbon or thorium oxide which are unsuitable for forming walls in conventional reactors can be used satisfactorily. Compared to alloys which resist high temperatures the best and which melt at
1595 [deg.] C approximately, thorium oxide for example can be used at temperatures above 2980 [deg.] C.

   This characteristic allows the use of reaction temperatures which far exceed those currently used and reactions considered possible.

  
in theory only can be effectively implemented.

  
A carbon fabric, the most advantageous refractory material in a first embodiment of a reactor tube according to the invention, is relatively inexpensive, readily available, and can form reactor tubes significantly larger in size than carbon tubes. porous castings currently available. Since the carbon fabric is normally flexible, any attempt to forcefully introduce an inert gas radially inwardly through a tube of such material will usually cause the tube to collapse. Thus, the invention relates to the deposition of a layer of pyrolytic graphite on the fabric so that the latter has sufficient rigidity for it to withstand the pressure difference existing between

  
the pressurized inert fluid chamber and the reaction zone. The deposition of a layer of pyrolytic graphite

  
on the fabric also allows adjustment of the porosity of the fabric.

  
The use of an inert protective fluid made possible essentially by the radiative coupling isolates the wall of the reactor from the stream of reactants and makes it impossible under normal operating conditions for the accumulation of precipitates or deposits and the plugging of the apparatus. When a corrosive shielding fluid such as water vapor is to be used, the surface of the tube, heating elements and thermal shielding which are maintained at elevated temperature and in contact with gas when the reactor is in operation may be coated with a thin layer of a refractory oxide, for example thorium, magnesium or zirconium.

   The refractory oxide can be deposited on these surfaces by heating the reactor to a temperature above the dissociation temperature of a volatile compound containing a metal, introducing this compound into the reactor chamber and dissociating the compound so that it a layer forms

  
metal on heated surfaces. Then a gas or some other such material. than molecular oxygen, can be introduced into the chamber so that the metal layer is oxidized and forms the desired refractory oxide. Alternatively, the refractory lining can be carried out in a single step when a volatile compound containing a metal which pyrolys directly as an oxide is used as a refractory deposition agent.

  
The use of radiative coupling also allows

  
precise and almost instantaneous adjustment of the transfer rate

  
heat, this adjustment being practically impossible in the case of conventional reactors with convention. In addition, the reactor of the invention can give a power density,

  
  <EMI ID = 18.1> design suitable for large-scale industrial applications gives a power density of approximately 180 W / cm <2>.

  
Even this lower number represents a great improvement over the value of 2-3 W / cm <2> usually obtained with conventional reactors. The use of a thermal shield delimiting the surface or surfaces of the black body in which all the reactions take place allows unusually favorable thermal yields.

  
The reactions which can be carried out according to the process of the invention, in the reactor of the invention, are numerous and varied. For example, organic compounds such as hydrocarbons noted, can be pyrolyzed as carbon and hydrogen without the problems of thermal buildup and runaway conventionally posed. Saturated hydrocarbons can be partially pyrolyzed as unsaturated hydrocarbons;

  
thus, propane and ethane can be dehydrogenated

  
in propylene and ethylene respectively. Unsaturated hydrocarbons can be partially pyrolyzed in the absence of hydrogen and form saturated hydrocarbons and more specifically, petroleum products can be thermally cracked. Thus, gas oil can easily be transformed into diesel fuel, kerosene, gasoline and leads to methane. Halogenated intermediates can be added to partially pyrolyzed hydrocarbons so that the compounds formed have an increased molecular weight. Hydrocarbons can be partially or totally pyrolyzed in the presence of water vapor and form carbon monoxide and hydrogen; more hydrogen can be added and the reaction can be started

  
  <EMI ID = 19.1>

  
fuels with high calorific value.

  
Mineral compounds can be pyrolyzed in an analogous manner. For example, salts or oxides of iron, mercury, silver, tungsten and tantalum in particular can be dissociated and give pure metals. Oxides of iron, nickel, cobalt, copper and silver, to name a few, can be directly reduced in the presence of hydrogen with the same result. This list is by no means exhaustive.

  
It is also possible to prepare new composite products by carrying out the process of the invention. For example, carbon or talc particles coated with silicon carbide can be produced. This product is an excellent abrasive, because in use it constantly breaks and forms new sharp surfaces. The parties

  
  <EMI ID = 20.1>

  
coated in a sealed envelope of another material such as carbon; this particular product is useful as a nuclear reactor fuel element.

  
The invention also relates to the final stage of the conventional aerobic incineration of garbage, in particular household garbage and wastewater. The relatively low temperatures used in common incineration processes allow the formation of organic peroxides and nitrogen oxides which are important contributors to photochemical fog and other forms of air pollution. As these compounds are not stable at the high treatment temperatures permitted according to the invention, the incineration effluent obtained can be very slightly polluted.

  
Further, the invention relates to the anaerobic high temperature destructive distillation and / or disassociation of wastes with formation of useful products such as carbon dioxide, activated carbon, hydrogen and cullet, among others. The addition of water vapor to this waste causes the creation of hydrogen and carbon monoxide which can be processed in conventional form and give combustible gases. Finally, the addition of hydrogen to this waste allows the preparation of heavy oils equivalent to those of petroleum and other petroleum products. Thus, significant reductions in atmospheric pollution and significant economic gains can be achieved by implementing the invention.

  
The invention constitutes an essential breakthrough in

  
the technical field considered. As it makes available for the first time a source of thermal energy which has never been mastered in this way, its possible applications are numerous and varied. In addition, the resolution of the problem of material strength, which was a very important problem for many years, makes possible the practical use of many useful chemical reactions.

  
  <EMI ID = 21.1>

  
implemented given the temperature limits imposed

  
to reactors operating by transfer by convection and / or conduction.

  
Other characteristics and advantages of the invention will emerge better from the description which follows, given with reference to the appended drawings in which:

  
- Figure 1 is a partial sectional elevation of an embodiment of a reactor according to the invention;
FIG. 2A is a section through the inlet end of a second embodiment of the reactor according to the invention;
- Figure 2B is a sectional view of the outlet ends of the second embodiment of the reactor according to the invention, Figures 2A and 2B showing the halves of the same structure, separated along the line so that the drawing can clearly represent certain details ;
FIG. 2C is a perspective in partial section of the second embodiment of the reactor of the invention, certain elements of which have been removed or shown schematically so that the operation appears clearly;
- Figure 3 is a section taken on line 3-3 of Figure 2A;

   
- Figure 4 is a section taken on line 4-4 of Figure 2B;
- Figure 5 is a section along line 5-5 <EMI ID = 22.1>
- Figure 6 is a perspective of part of the heater tube of the reactor of the second embodiment of the invention;
- Figures 7A, 7B, 7C and 7D together show a partial sectional elevation of a reactor according to the invention, the representation being divided by the lines AA, BB and CC so that the drawing can be large enough so that it represents some details; <EMI ID = 23.1> of Figure 7A; <EMI ID = 24.1> of Figure 7B;
- Figure 10 is a section taken on line 10-10 of Figure 7B;
- Figure 11 is a section taken on line 11-11 of Figure 7C;

  
- Figure 12 is a section along line 12-12 <EMI ID = 25.1>
FIG. 13 is a section of a post-reaction treatment assembly of another embodiment of the reactor of the invention;
- Figures 14A and 14B are a composite elevation in partial section of the inlet assembly of another <EMI ID = 26.1>

  
at line D-D so that the drawing is large enough to clearly show certain details;
FIG. 15 is a side elevation partly in block diagram form of a reactor according to the invention combined with a pretreatment apparatus for introducing solid reactants into the inlet assembly of the reactor according to the invention;
FIG. 16 is a synoptic and schematic diagram representing the attack and refractory lining installations of the reactor according to the invention;
FIG. 17 is a diagram partly in block form of the temperature regulation circuit of the reactor of the invention;

  
FIG. 18 is a graph showing the variation in the electrical resistance of a heating element of the reactor of the invention as a function of the temperature and of the number of layers of refractory fabric forming the element; and
- Figure 19 is a diagram partly in block form illustrating the implementation of the various control circuits of the reactor of the invention. Figure 1 shows a first embodiment <EMI ID = 27.1>

  
attention. which comprises a tube 11 having an end 12 of <EMI ID = 28.1>

  
17 of the reactor. The tube 11 is made of a material that is practically transparent to radiation. Suitable materials having a very low absorption coefficient are glass,

  
  <EMI ID = 29.1>

  
hot sintered, "Pyrex" (borosilicate glass), "Vycor"
(silicate glass) and sapphire, organic polymers such

  
  <EMI ID = 30.1>

  
polyethylene, polypropylene and polystyrene, and

  
mineral salts such as the halides of sodium, potassium, cesium, lithium or lead.

  
In this specification, the term "radiation"

  
and the expression "radiant energy" designates all types

  
of radiation including high energy nuclear particles. However, as they cannot be used in practice at present, only electro-

  
  <EMI ID = 31.1>

  
waves between about 100 microns and 0.01 microns are the primary source of energy that is used primarily.

  
During operation of the reactor 10, a fluid practically transparent to radiation enters through the inlet
18, circulates in the annular channel and cools the tube 11, then leaves through the outlet 19. This fluid can be gaseous or liquid, and for example fluids having low absorption coefficients are liquid or gaseous water, heavy water, nitrogen, oxygen and air.

  
A device for introducing an inert fluid into the chamber 17 through an inlet 20 comprises two laminar diffusers 21 and 22 placed near the end 12 of the inlet.

  
Diffusers 21 22 may have a honeycomb or other configuration such as &#65533; the fluid sent under pressure flows in a practically laminar fashion. The inert fluid thus penetrates practically axially into the chamber 17 and forms a protection for the internal face of the tube 11, and it

  
is collected so that it circulates again after exit 23.

  
Inert fluid is practically transparent to radiation

  
  <EMI ID = 32.1>

  
nent for this purpose are simple gases such as helium,

  
neon, argon, krypton and xenon, complex gases which do not decompose to form a solid product such as hydrogen, nitrogen, oxygen and ammonia, and liquid or gas water . The term "inert" as used herein applies to two properties, the ability of the fluid to chemically react with the material of tube 11 and the ability of the fluid to chemically react with the treated materials. Thus, the selection of an "inert" fluid depends in all cases on the particular atmosphere. Unless otherwise indicated, it is advantageous that the fluid is inert with respect to the tube and it is usually desirable that it be inert in the case of the reaction being carried out. However, in certain cases, the "inert" protective fluid also participates in the reaction, for example when the particles

  
iron or carbon react in the presence of water vapor protection with the formation of iron oxide and hydrogen or carbon monoxide and hydrogen respectively.

  
The reagents enter the chamber 17 through the inlet 24 at the end 12 of the tube 11. They follow a path

  
  <EMI ID = 33.1>

  
the inert protective fluid practically in the center of the chamber 17 out of contact with the tube 11.

  
A source of very intense radiation (not shown) is disposed in a polished reflector 31 mounted on a frame 32 outside the tube 11. The source of radiation

  
yours may be a plasma arc, a heated filament, a seeded flame, a pulsed flashlight or other suitable device; a laser can also constitute the source but, at present, the technology is not sufficiently developed for the use to be profitable within the framework of the invention. The radiation created by the source is collected by the reflector 31 and transmitted through the tube 11 into the chamber 17 so that they coincide with at least part of the path 25. A sufficient quantity of radiation is thus absorbed so that the temperature of the rays. reagents reach the value necessary to initiate and maintain the desired chemical reaction. As previously indicated, the tube 11, the cooling fluid and the inert shielding fluid are practically transparent to radiation.

   Thus, they do not significantly interfere with the transmission of energy to the stream of the reactants and remain practically cold. Thus, the tube 11 is not subjected to appreciia thermal stresses. bleeds and does not receive precipitates or other deposits that might accumulate normally.

  
The above description assumes that the reagents

  
  <EMI ID = 34.1>

  
tion of radiation. However, in the contrary case, a material absorbing the radiations, called auxiliary material,

  
  <EMI ID = 35.1>

  
at least at one point with path 25. In the embodiment of Figure 1, the auxiliary absorbent material

  
  <EMI ID = 36.1>

  
bone or other suitable material entering chamber 17 with the reagents through inlet 24 and absorbing sufficient radiation so that the temperature of the reagents reaches the desired value.

  
Alternatively, the auxiliary material can be a liquid, for example pitch, asphalt, linseed oil or diesel fuel, and it can contain solutions, dispersions, gels and suspensions of. various materials which can be easily chosen from

  
the materials available according to specific criteria. The auxiliary material can be a gas advantageously exhibiting an absorption in the electromagnetic spectrum between about 100 and 0.01 microns; such gases are in particular ethylene, propylene, nitrogen oxides, bromine, chlorine, iodine and ethyl bromide. Auxiliary material can also be solid, eg carbon, placed in chamber 17 along at least part of the reactant path 25.

  
Another device raising the temperature of the reaction to the desired value may comprise an electrically heated element, an electric arc or a flame placed in the chamber 17 and coinciding with at least part of the path 25. In this case, the heat source trigger is autonomous and is not formed by the device creating the radiation. Such a device is particularly useful when the reagents themselves are transparent to radiation, but when at least one of the reaction products absorbs. Thus, when the intended reaction is started, the device for raising the temperature can be stopped because the products of the reaction absorb enough radiation to keep the reaction going.

   Likewise, when using an auxiliary material, this may no longer be introduced or may be withdrawn when the reaction has started, for example by means of a control device. An example of a reaction in which an auxiliary material or triggering device needed only at the start is the pyrolysis of methane as carbon and hydrogen.

  
As indicated above, some reactions are partially or totally reversed when the reaction products are not cooled immediately and rapidly. To this end, a device 40 for cooling the reaction products can be placed in the chamber 17 near the outlet end 14 of the tube 11. An embodiment of the device 40 is placed substantially in the center in the chamber 17 and comprises a tubular member 41 having an internal channel 42 in which circulates a cooling fluid such as water. The inner surface of tube 42 is intended to absorb radiation.

   As the reaction products, remaining reagents, and auxiliary materials, if any, pass through tube 41, heat is rapidly transferred by radiative coupling and the material is rapidly cooled so that unwanted chemical reactions are avoided.

  
Consider now Figures 2A to 6 and in particular Figures 2A to 2C which show a second embodiment of reactor 60 according to the invention which comprises a tube 61 having an inlet end 62 and an outlet end 63, the interior of the tube 61 giving a chamber 65 of the reactor. The tube 61 is made of a porous material which can emit radiation, the diameter of the pores being advantageously between approximately 0.025 and 0.5 mm in order

  
  <EMI ID = 37.1>

  
through the wall of the tube and forms a suitable protection. Other walls, for example in the form of webs, screens or various types of perforations can be used for the same result. The tube 61 can be made of a material such as graphite, carbon, sintered stainless steel, sintered tungsten or sintered molybdenum, or of a mineral material such as oxides of thorium, magnesium, zinc, aluminum or of zirconium in particular. Tungsten,

  
nickel and molybdenum can also be used in the form of a cloth or a screen.

  
A sealed tubular container 70 under pressure, advantageously made of stainless steel, surrounds the tube 61.

  
  <EMI ID = 38.1>

  
seals 71, 72, 73, 74 and 75, 76 which connect the various parts of the reactor 60. The flanges 72, 73 and 76

  
  <EMI ID = 39.1>

  
79 stainless steel respectively, forming pressure-resistant seals. The reactor tube 61 can slide at one end in a sleeve. 81 of graphite which allows the elongation of the tube 61 which can take place during

  
  <EMI ID = 40.1>

  
The container 70 further comprises an inlet 83

  
inlet of an inert fluid which, in the embodiment of Figure 1, is substantially transparent to radiation. The inert fluid is first directed under pressure into a chamber 85 formed between the tube 61 and the wall of the container 70. Then, the fluid passes through the wall of the tube 61 into the chamber 65 and forms a protection of the internal face. tube 61.

  
A vessel cooling device 70 includes coils 87 placed around the outer surface of vessel 70. Coils 87 are preferably covered with a flame sprayed aluminum coating which improves thermal contact between vessel 70 and them. coils 87 and increases the cooling efficiency.

  
The coils 87 are also placed around an observation channel 88 formed in the wall of the container.

  
As clearly shown in Figures 2A and 3, the reagents enter chamber 65 through the inlet end 62 of the tube 61. A reagent introduction device comprises an inlet portion 90 tightly mounted on the flanges. 71, 72 near the inlet end 62 of the tube 61. The reagents are entrained in a gas stream through the inlet 91, in front of a tangential partition 92 and in a chamber 93 under pressure defined between an outer wall 94 and a diffuser 95. A material suitable for

  
  <EMI ID = 41.1> wire mesh. As in the case of Figure 1, the reagents follow a predetermined path axial with respect to

  
to the tube 61 and are delimited by the gas shielding practically in the center of the chamber 65 out of contact with the internal wall of the tube.

  
In the second embodiment, the tube 61 itself creates the very intense radiations directed towards the center, in substantially coincidence with at least part of the path of the reactants. Heating is provided by several

  
  <EMI ID = 42.1>

  
laughing at the tube 61 and around it at regular intervals; heat from electrodes 100 is transmitted to tube 61 by radiation. In the second embodiment as shown in Figures 2A, 5 and 6, the electrodes 100a and 100b for example are buried at one end in a

  
  <EMI ID = 43.1>

  
circuits. As shown more precisely in Figures 2B and 4, each electrode 100a-100f is mounted at the other end in a copper electrode 104 forming a bus bar. Although the apparatus comprises six electrodes 104, only one has been shown in FIG. 4 for reasons of comparison. <EMI ID = 44.1>

  
phenolic and a ceramic insulator 106. The electrode 104 is cooled by water flowing through an internal channel.
107, through an input 108 and an output 109. An electrical connection 110 transmits a high current. A polytetrafluoroethylene gasket 111 aids in suppressing leaks from vessel 70. The electrical system shown is particularly suitable for a three-phase supply. However. However, other facilities may be used depending on the circumstances. The invention also relates to the case where the porous tube 61 is itself heated directly by electrical resistance, the electrodes 100 then being eliminated.

  
The thermal efficiency of the heater, of the tube is further improved by a thermal shield 120

  
molybdenum which forms the surface which delimits the black body reflecting electromagnetic radiation from the electrodes 100 towards the tube 61. Thus, the shielding 120 reflects

  
heat rather than transferring it, and constitutes an insulator so that it can be of any material exhibiting this characteristic and capable of withstanding the temperatures created by the electrodes 100. The shield 120 is placed in the receptacle 70 radially to the side. outside with respect to the electrodes 100 and it preferably comprises a flat strip of rectangular section wound in the form of a series of helical turns. This construction allows the penetration of the inert protective gas through the inlet 83 and its

  
  <EMI ID = 45.1>

  
As in the embodiment of Figure 1, an auxiliary absorption material or other device

  
trigger can be used where appropriate. Absorption aids enter chamber 65 through

  
an inlet 121. In addition, a device 125 for cooling the reaction products of the type already described or different can be used and prevents any chemical reaction

  
undesirable that can occur when the reaction products are not cooled immediately after their formation.

  
The essential advantage of the second embodiment over the first is that, in the second embodiment, the inert fluid is introduced into the chamber 65 in a radial inward direction while, in the first embodiment, it is introduced. axially in chamber 17. It should be noted that a laminar flow can be maintained for a relatively short distance only before the turbulence causes mixing and destroys the integrity of the gas shield. As the radial introduction of the gas does not require a laminar flow of the

  
  <EMI ID = 46.1>

  
much greater reaction. It suffices that, in the second embodiment, the absolute pressure of the inert fluid is greater than that of the stream of the reactants so that the reactants and / or the products of the reaction do not strike the tube 61. This characteristic facilitates the implementation. of such an apparatus on a large scale industrially.

  
Another difference between the two embodiments is that the tube 11 of figure 1 is cooled while the tube 61 of figure 2 needs to be heated and can operate at temperatures exceeding 2980 [deg.] C, for example when l porous thorium oxide is the material. Although the cold wall is better able to withstand a pressure because it is not subjected to thermal stress, the hot wall 61 does not undergo a pressure gradient, except possibly the very small pressure difference prevailing between the inert fluid and the flow of reagents. Pressure

  
is supported by the wall of the container 70 made of stainless steel which is obviously cooled by the coils 87

  
and does not undergo thermal stress. Thus, a refractory material such as carbon or thorium oxide,

  
capable of withstanding temperatures well above those tolerated by conventional reactor wall materials and unsuitable in conventional convection reactors, can be used for the first time in a practically usable apparatus operating at extremely high temperature. '

  
The invention also relates to a third embodiment which combines features of the first two. Thus, the reactor tube can be made of a porous material which is practically transparent to radiation. Such materials are porous quartz, porous sintered glass, and 1 &#65533; porous sapphire.

  
An inert fluid substantially transparent to radiation may also be introduced into the chamber radially inwardly through the porous wall and not axially in laminar form as described in the first embodiment. Radiation is created, collected

  
  <EMI ID = 47.1>

  
the first embodiment.

  
The third embodiment provides the high power density of the first embodiment and the radially injected fluid flow of the second embodiment. However, at present, the second embodiment is more suitable for large-scale industrial applications since the radiation is obtained by ordinary electric heating in a resistor. The second embodiment can therefore be easily produced and maintained. In addition, this second embodiment can implement all the processes and all the reactions considered by simply adjusting the residence time of the reagents in the chamber, so that the reduction in the power density is compensated for.

  
We now consider FIGS. 7A to 15 inclusive which represent a fourth embodiment of the reactor.

  
  <EMI ID = 48.1>

  
an improvement of the second embodiment; this reactor comprises an inlet set 200 and a set 300

  
  <EMI ID = 49.1>

  
reactor are now described.

  
(A) A reactor tube 401 having an inlet end 402 and an outlet end 403 defines a reaction zone 404 in at least part of the interior. Tube 401 is of a fabric of a fibrous refractory material capable of emitting sufficient radiation so that the temperature of the reagents in zone 404 reaches the value necessary to initiate and maintain the desired chemical reaction.

   The fabric has numerous pores, the diameter of which allows a uniform and sufficient flow of an inert, practically transparent to radiation, flow through the wall of the tube, so that this fluid forms a pro-. tection of the internal surface of the tube 401.
(B) A tight tubular pressure vessel
(which includes an inlet assembly section 201, an electrode assembly section 301, a main assembly section 405 and a processing assembly section 501 <EMI ID = 50.1>

  
bre 406 for the inert fluid under pressure between the tube
401 and the container. The inlet and outlet ends
402 and 403 of the tube 401 cooperate in a sealed manner with the

  
chamber 406 under pressure. The container has a first inlet 408 and a second inlet 409 for admitting an inert fluid directed under pressure into the chamber.

  
406 and through wall 401 in area 404.

  
(C) A device is intended for the introduction of the gaseous, liquid or solid reagents into the zone 404 through the inlet end 402 of the tube 401. The reagents are directed along a predetermined path axially relative to the tube 401 and they are delimited by the protection so that they are practically in the center of the zone 404 out of contact with the internal wall of the tube 401.
(D) An electrical device consists of elements
302a, 302b and 302c placed in the chamber 406 at a certain radial distance from the tube 401, outwards, and it heats the reactor tube to a temperature at the-

  
  <EMI ID = 51.1>

  
desired chemical is triggered and sustained. The radiation is directed into zone 404 so that it substantially coincides with at least part of the path of the reactants.

  
(E) A thermal shield 401 is disposed in the pressure vessel and substantially surrounds the heating elements 302a to 302c and the area 404 to define a cavity forming a black body. Shield 410 reflects radiation inward toward reaction zone 401. A. Consider the input assembly first.

  
Figures 7A and 8 represent more precisely

  
the container inlet assembly section 201 in the form of a tubular member having two flanges 202 and 203 at its ends <EMI ID = 52.1>

  
sealing ring 205 which is itself fixed in a sealed manner

  
to the flange 202. A main atomization gas inlet tube 206 passes into the block 204 and is permanently attached thereto by a support flange 207. An O-ring 209 placed in the flange 207 seals between the tube 208 and the flange 207. An inlet fitting 210 is attached to one end of the tube 206 as shown in FIG. 7A. The atomization gas enters a chamber 211 under pressure through an inlet 212.

  
A main liquid reagent inlet tube 214 is disposed in tube 206, substantially the same length as the latter. A main liquid reagent enters the

  
  <EMI ID = 53.1>

  
As clearly shown in Figure 7B, a nozzle 216 for forming a mist or mist

  
  <EMI ID = 54.1>

  
of the cover 217 is practically parallel to that of the tube 401 of the reactor. During operation, liquid reagent and atomizing gas enter the tubes under pressure
214 and 206 respectively and mix under pressure in the nozzle 216. The liquid reagent is then dispersed at the outlet of the nozzle in the form of a mist which absorbs the radiation. The cover 217 facilitates the maintenance of the fog in the center in a reaction zone 411, preliminary to the tube 401.

  
As shown clearly in Figures 7A and 8, the inlet assembly of the considered reactor may include

  
  <EMI ID = 55.1>

  
daire facilitating the introduction of other liquid reagents. The device for introducing the secondary liquid reagent is similar to that of the main liquid reagent, from the point of view of construction and operation, e &#65533; it comprises, for example, secondary tubes 21 Sa to 219c for the atomization gas inlet and misting nozzles such as
220a (the other nozzles are not shown). The references 221 and 22 respectively denote a secondary liquid reagent inlet and a secondary atomization gas inlet.

  
The foregoing description assumes that the reagents themselves either have a relatively high coefficient of radiation absorption, or may form a mist which absorbs radiation. However, if not, auxiliary radiation absorbing material as previously described must be introduced into reactor zone 404, coincident with at least one point on the path followed by the reactants.

  
As shown in Figure 7A, a sweep gas facilitates the direction of the mist to zone 404. The sweep gas enters block 204 through a connector 225.

  
  <EMI ID = 56.1>

  
relative to the tube 401 towards the zone 411. As shown in FIGS. 7A and 8, a channel 226 for observing the <reaction allows axial observation of zone 404.

  
B. We now consider the set of electrodes.

  
Figures 7B, 9, 10 and 11 show the tubular section 301 of the pressure vessel corresponding to the electrode assembly and having two flanges 303 (Figure 5A) and 304. The section 301 is secured by the lower flange 303 to the second flange 203 of section 201 in a sealed manner. A coolant channel 305 is formed between section 301 and a cooling jacket 306 of the electrode assembly. A cooling fluid enters the channel 305 through an inlet 307 and leaves it through an outlet 308.

  
As clearly shown on the? Figures 7B and 9, copper electrodes 309a to 309f in the form of bus bars are mounted on the second flange of section 301 from which they protrude. Although the device comprises six

  
  <EMI ID = 57.1>

  
gure 7B for the sake of simplicity. Each electrode 309 comprises a flange 310 made of phenolic resin and a ceramic insulator 311. Each electrode 309 is cooled by a fluid, preferably ethylene glycol, circulating in an internal channel 312, having an inlet 313 and an outlet 314.

  
Reference 315 represents an electrical connection. A 316 polytetrafluoroethylene seal assists in suppressing leakage from the pressurized chamber 406 which contains inert fluid. Although the electrical circuit used in the reactor considered has three-phase connections

  
star as shown in Figure 17, other circuits are suitable depending on the circumstances.

  
Reference is now made more specifically to FIGS. 7B and 7C which represent each electrode 309 fixed by interlocking to a first end of a rigid extension 317 of carbon electrode. The extensions 317 protrude through a first end section 412

  
heat shield 410 without being in contact with it and are attached at a second end to a curved support
318 of heating element. Figure 10 indicates that the heating elements 302a-302c are attached at a first end to one of the supports 318 and are spaced circumferentially.

  
  <EMI ID = 58.1>

  
heating elements are attached at a second end to a central three-phase connection ring 319 shown in

  
FIGS. 7C and 11. Each element 302 is advantageously made of a fabric of a fibrous refractory material such as

  
than graphite or carbon. The supports 318 and the ring
319 may be of an electrically conductive refractory material such as carbon.

  
C. We now consider the main set.

  
Figures 7B, 7C and 10 show the tubular section 405 of the pressure vessel corresponding to the

  
  <EMI ID = 59.1>

  
405 is fixed by its first flange 414 to the second flange
304 of section 301 in a sealed manner. A main assembly coolant channel 416 is formed between section 405 and a cooling jacket 417. The channel 416 is further delimited by a spiral partition 418. Coolant enters the channel
416 through entry 419 and exit through exit 420.

  
The reactor tube 401 comprises three zones, the pre-reaction zone 411, the reaction zone 404 and a post-reaction zone 422. As indicated above, the tube 401 is made of a fabric of fibrous refractory material, for example carbon or graphite. The fabric can be knitted, woven or non-woven. The tube 401 is fixed at the outlet end 403 to a support ring 424 which is itself fixed by an anchoring block 425. Tube 401 is attached at its inlet end 402 to an inlet ratio ring 426 which is itself sealingly connected to a tubular bellows 427 placed in section 201 of the inlet assembly. An inlet end of the bellows 427 is sealed between the flanges 202 and 205 so that the inlet end of the tube 401 remains sealed from the chamber 406.

   The bellows 427 is deformable and allows the axial expansion and contraction of the tube 401.

  
A device for applying an axial tensile force to the tube 401 comprises three identical sets regularly distributed around the circumference of the section 201.

  
For convenience, the assembly 428 shown in FIG. 7A is described. Each assembly 428 comprises a rod 429 movable in translation and intended to be pushed, fixed at one end to the ring 426 and at the other end to

  
  <EMI ID = 60.1>

  
supported in a pad 431 with which it cooperates in a sealed manner via an O-ring 432. An eyelet 433 bolt is fixed to the plate 430 and fixed

  
a cable 434 substantially parallel to the longitudinal axis of the reactor and passing over a pulley assembly 435. A counterweight 436 attached to the other end of the cable 434 exerts a force which keeps the tube 401 under tension in the axial direction.

  
  <EMI ID = 61.1>

  
438 placed in section 404, radially outwardly of heating elements 302a to 302c and between first section 412 and a second end section 439 of the shield.

  
  <EMI ID = 62.1>

  
The circumferential tie of the shield 410 may be disposed towards the set 300 of electrodes so that it comprises a second circumferential part 440 as shown in FIG. 7B. Although molybdenum is initially chosen which is a satisfactory material for providing thermal shielding of the type required in the high temperature chemical reactor of the invention, it is advantageous to <EMI ID = 63.1>

  
example in pyrolytic graphite or in "Grafoil" material from Union Carbide Corporation.

  
Observation channels 441 and 442 for radiometers are formed in section 400. Channel 442 allows observation and measurement of the temperature of reaction zone 404 and channel 441 allows observation and measurement.

  
  <EMI ID = 64.1>

  
D. We now consider the treatment set by posterior reaction.

  
As shown in Figure 7C, a first flange 302 of the section 501 of the pressure vessel corresponding to the post-treatment is sealingly attached to a fluid-cooled interface flange 503 which is itself sealingly secured to the second flange 415 of the main assembly section. A coolant channel 504 is formed between the post-processing assembly cooling jacket 505 and section 501. Coolant flows through channel 504 between inlet 506 and outlet 507. A channel
509 observation for radiometer allows the observation and measurement of the temperature in the zone 422 of posterior reaction of the tube 401.

  
The reaction products leaving the outlet end 403 of the tube 401, in the embodiment of Figures 7A to 7D, pass into a first section 510 of a radiator or cooler 511. As shown in Figures 7C and 7D, the first section 510 of cooler 511 includes

  
an internal tubular wall 512 and an external tubular wall 513 which define between them a channel 514 of cooling fluid. A spiral partition 515 directs this cooling fluid which enters through inlet 516 and escapes through outlet 517. A first thermocouple probe 518 <EMI ID = 65.1>

  
the temperature of the reaction products near the outlet.

  
As shown in Figure 7D, the first section 510 of the cooler 511 is connected to a second section 520 by flanges 521, 522. The second section 520 has an inner wall 524 and an outer wall 525 delimiting between them a channel 526 for one. coolant. The latter enters the channel 526 through an inlet 527 and leaves it through an outlet 528. Thermocouple probes 530 and 531 allow the measurement of the temperature of the reaction products entering the second section.
520 and escaping from it respectively.

  
  <EMI ID = 66.1>

  
Post-reaction treatment assembly 500a comprises a pressure vessel section 501a corresponding to the post-reaction treatment assembly and having a flange 503a sealed to an interface flange such as
503 of Figure 7C, cooled by a fluid. A coolant channel 504a is formed between the post-reaction treatment assembly cooling jacket 505a and section 501a. The cooling fluid flows in the channel 504a from the inlet 506a to the outlet 507a. A canal

  
  <EMI ID = 67.1>

  
tion and the measurement of the temperature in zone 422.

  
The reaction products leaving exit 403

  
of the tube 401 in the embodiment of FIG. 13 pass

  
  <EMI ID = 68.1>

  
tre-current and with a variable profile placed in abutment against the outlet 403 of the reactor at its inlet end 533. The exchanger 532 comprises an internal tubular wall made of refractory material 534, an external tubular wall made of refractory material 535 concentric with the wall 534 and outside of it, and a spiral partition of refractory material

  
  <EMI ID = 69.1>

  
annular spiral coolant channel 537. The walls 534 and 535 and the partition 536 together form

  
a high temperature spiral heat exchanger 544 supported by an elastic cushion 545 of carbon felt placed on an end plate 546 of the section 547 of the pressure vessel corresponding to the heat exchanger.

  
  <EMI ID = 70.1>

  
and communicate with channel 537.

  
In the particular embodiment of Figure 13, after circulation in the channel 537 of fluid. variable, adjustable and predetermined cooling

  
  <EMI ID = 71.1>

  
541 near 1 * inlet end 533 of exchanger 532.

  
Then the coolant passes through a channel
542 entry of a block 425a for anchoring the reaction tube in the pressure chamber 406 ,. In this case, it is clear that the coolant used must be the same as that of the chamber 406 or must be at least compatible with it. However, as the operation of the exchanger 532 does not require the circulation of the cooling fluid in the chamber 406, other circuits and circulation devices are possible. In this case, the selection of the coolant is not limited by the criteria indicated above. Shirt

  
  <EMI ID = 72.1>

  
heat changer is placed radially outside the pressure vessel section 547 corresponding to

  
  <EMI ID = 73.1>

  
channel 549 entered an inlet 550 and an outlet 551.

  
E. Now consider the input set of solid reagents.

  
The inlet assembly 200a of the embodiment of Input <EMI ID = 74.1> of Figures 7A and 7B, but a device for introducing a main solid reagent of the inlet set 200a replaces the device for introducing a main liquid reagent of the assembly 200. For convenience, no description will be made with reference to the embodiment of FIGS. 14A and
14E that the characteristics which differ from the embodiment of Figures 7A and 7B.

  
A solid reagent inlet tube 232 passes through block 204 and is secured thereto by a support flange 235. An advantageously finely divided main solid reagent enters tube 232 through inlet 233 at flange 235 and leaves tube 401 near

  
  <EMI ID = 75.1>

  
  <EMI ID = 76.1>

  
parallel to that of tube 401. Cover 217 facilitates the maintenance of finely divided solid reagents in the center of preliminary reaction zone 411.

  
In FIG. 15, a device 238 for supplying solid reactants cooperates with a high temperature reactor having an inlet assembly 200a of the tube shown.

  
in Figures 14A and 14B. 240 feed hopper

  
  <EMI ID = 77.1>

  
241 which itself feeds a sieve 242. The coarse product
245 from screen 242 is recycled to crusher 241 and the fine product 243 reaches a hopper or accumulator 244 attached to an elongated tubular casing 246. A helical screw
Power 247 can rotate in housing 246 and a motor 248 drives it. A pressurized sealing fluid can be introduced into the housing 246 by an inlet nozzle 249 which is located downstream of the hopper 244; the interior of tube 401 is thus separated from the atmosphere. Liquid reagent and sealing fluid are drained from the housing
246 into the reactor through an outlet 250.

  
F. We now consider chemical attack devices

  
and coating with a refractory material.

  
For reasons indicated below, it is considered that a refractory coating can be deposited on

  
surfaces of tube 401, elements 302 and heat shield 410 which are exposed to shielding gas and high temperatures during reactor operation. The refractory coating can be, for example, of pyrolytic carbon or of refractory oxide such as thorium, magnesium, zinc, aluminum or zirconium oxide.

  
It is also believed that portions of the surface of tube 401 may undergo erosion or selective chemical attack.

  
  <EMI ID = 78.1>

  
fractal and etching is schematically shown in Figure 16 and it includes a first device 601

  
deposit refractory agent dosage. having a reservation

  
602 of carbon dioxide connected to a 603 dosing line

  
of carbon dioxide. This line comprises a shut-off valve 603 connected to a needle valve 605 and to a flowmeter 606. A first supply line 608 connects the line 603 to a line 607 for supplying the mixture gas.

  
A second refractory depositing agent metering device 610 comprises a reserve 611 of gaseous vehicle connected to a pipe 612 for metering the gaseous vehicle.

  
  <EMI ID = 79.1>

  
needle valve and a 6i5 flowmeter. Line 612 is connected to a bubbling tube 616 placed in a reservoir 617 containing a solution of a volatile compound containing a medium.

  
  <EMI ID = 80.1>

  
control 618 which detects the temperature of the reservoir using a thermocouple 619 and heats the reservoir if necessary using an electric heating sheath 620.

  
An outlet end 621 of the tube 616 is immersed in the solution of the reservoir 617. An outlet 622 of the reservoir 617 is connected to a second supply line 623.

  
which starts from the reservoir 617 at a point which is above: the surface of the solution. The second line 623

  
is also connected to line 607.

  
In an attack agent dosing device 625

  
chemical, a reserve 626 of such an agent is connected to a line 627 for dosing such an agent which comprises er.

  
  <EMI ID = 81.1>

  
and a flowmeter 630. A third supply line 631 connected to the line 607 is also connected to

  
line 627.

  
The three lines 608, 623 and 631 all feed to line 607 which goes to a tee
632. A first line 637 includes a first valve 634 and is connected to a first inlet of a valve.

  
  <EMI ID = 82.1> branch line 636 includes a second valve 637 and is connected to a first inlet of a distributor
638 of mixing with a purging gas.

  
A reserve 640 of inert fluid is connected to an inert fluid metering line 641 which includes a shut-off valve 642, a needle valve 643 and a flow meter 644 connected to a second inlet of the distributor 635.

  
An outlet thereof is connected to a line 645 which is itself connected to the inlets 408 and 409 of the pressure vessel so that inert fluid enters the chamber 406. A pressure gauge 646 is connected to the line.
645 and communicates with chamber 406 so that it gives the pressure of the inert fluid in this chamber. A valve
647 outlet of the pressure chamber is also connected

  
to the pipe 645 and allows the evacuation of the fluid from the chamber 406.

  
A supply 648 of purge gas is connected to a metering line 649 which includes a shut-off valve 650, a needle valve 651 and a flow meter 652 which is connected to a second inlet of the distributor 638. An outlet of the distributor 638 is connected to a line 653 for supplying scavenging gas which is itself connected

  
  <EMI ID = 83.1>

  
reaction of the reactor.

  
As shown in Figure 7D, a valve
Reaction tube outlet closure 655 is attached to second section 520 of cooler 511 by flanges 555 and 656.

  
When the reactor is in operation, a pressure differential must be maintained between the inert fluid in chamber 406 and the gas in tube 401 so that the inert fluid flows uniformly in a radial direction inward through the porous wall. of the tube 401. It is thus advantageous that the fabric of the tube 401 is sufficiently rigid so that the pressure difference can be maintained without sagging towards the interior of the tube 401. Thus, one

  
  <EMI ID = 84.1>

  
The pyrolytic bone can be deposited on portions of the fibrous refractory material of the tube 401, within the black body, so that the stiffness or dimensional stability of the fabric is improved.

  
during the deposition of such a coating, the valve 655 for closing the outlet of the reactor is closed and the tube '
401 is raised to around 1900 [deg.] C. Then the valve 650

  
of line 649 is open, valve 642 of line 641 is closed, and valve 647 is open so that purge gas flows inside the

  
  <EMI ID = 85.1>

  
porous part of the tube 401 in the chamber 406 and finally through the inlets 408 and 409 and the valve 647. The tube 401 has

  
therefore tend to expand to its maximum diameter. Then, the valve 604 of the line 603 is opened. Needle valves 605 and 651 are set to determine the flow rates of carbon dioxide and purge gas, respectively, to the proper values indicated by flow meters 606 and 652. Valve 634 is closed and valve 637 open so that gas carbon circulates in line 608, line 607, fitting 636, line 636 and distributor 638, the gas then mixing with the purging gas and reaching the interior of the tube

  
  <EMI ID = 86.1>

  
Carbon dioxide dissociates when it comes into contact with heated surfaces and deposits a coating of pyrolytic graphite. Thus, pyrolytic graphite is generally deposited on the parts of tube 401, elements 302

  
and shielding 410 which are inside the cavity forming the black body.

  
As the part of tube 401 which is in zone 411 is outside the blackbody and therefore cannot be conveniently heated to temperatures above

  
decomposition temperature of the carbonaceous gas, a stainless steel mesh 450 shown in Figures 7A and 7B prevents inward collapse of flexible tube 401 when the inert fluid exerts differential pressure, but an increase in the tension applied to the porous fabric gives the same result.

  
The diameter of the pores in the wall of the tube can be reduced or enlarged when the reactor is in operation, by mixing a refractory deposition agent or a chemical etchant with the inert fluid, so that the flow rate of this fluid to through the walls of the tube 401 is adjusted. The difference in pressures between chamber 406 and reaction zone can be monitored using manometers 646 and

  
654 and the flow of inert fluid through the wall can

  
  <EMI ID = 87.1>

  
When the pressure difference becomes too low for the desired flow rate of inert shielding gas, the pore diameter of the wall can be reduced by opening valve 604 and adjusting valve 605 so that carbon dioxide from reserve 602 circulates. in the pipe 603. The valve 637 is closed and the valve 634 is opened so that the carbon dioxide reaches the distributor 635 then into the chamber 406 through the pipe
645 and inlets 408 and 409. Valve 647 remains closed and valve 655 remains open during normal reactor operation. Carbon dioxide dissociates on contact with hot surfaces in the reactor. Thus, the carbonaceous gas circulates in the pores of the fabric forming the wall of the tube 401 and dissociates, depositing a coating of pyrolytic graphite which reduces the diameter of the pores.

   As the pressure difference on either side of the tube wall

  
  <EMI ID = 88.1>

  
ductior. The porosity of the tube can be controlled with the manometers 654 and 646 and the flowmeter 644 during the deposition of the graphite. When the differential pressure exceeds a predetermined value, the growth of the graphite coating can be stopped by closing the valve 604.

  
pipe 603. The entire operation of reducing the diameter of the pores in the wall can be carried out without interrupting the operation of the reactor.

  
Conversely, increasing the pore diameter of tube 401 may be necessary. In this case, a chemical etchant such as water vapor or molecular oxygen from the reserve 626 is mixed with the inert fluid by controlling the valve 628, adjusting the valve.
629 of line 627, closing of valve 637 and opening of valve 634. Etching agent mixes with the inert fluid in distributor 635 and flows into chamber 406 through inlets 408 and 409. L agent attacks hot surfaces in contact with which it is

  
finds and increases the pore diameter of the heated portion of the tube 401 &#65533; The flow of etchant can be maintained until pressure gauges 654 and 646 indicate a sufficiently small pressure difference at tube 401 for the flow of inert gas monitored by flowmeter 644. Operation can be performed. be carried out during operation of the reactor, in the same way as the reduction in the diameter of the pores by carbon dioxide.

  
In some applications, the use as an inert fluid of water vapor or other material which reacts chemically with the treated materials may be advantageous. Corrosion of reactor materials can be avoided or at least retarded by depositing a coating of a refractory oxide, such as thorium, magnesium, zinc, aluminum or zirconium oxide, on the parts of the reactor. tube 401, heating elements 302 and thermal shield 410 which are in contact with the inert fluid and which are

  
  <EMI ID = 89.1>

  
refractory, a refractory deposition agent which is a volatile compound containing a metal such as methylmagnesium chloride, magnesium ethylide or zirconium n-amyloxide can be used. Methylmagnesium chloride, for example, decomposes on a surface heated to about 593 [deg.] C and leaves a coating of metallic magnesium. This, when hot, then oxidizes upon introduction of water vapor or molecular oxygen into the

  
  <EMI ID = 90.1>

  
Magnesium both generally decompose on heated surfaces with the formation of zirconium oxide or magnesium oxide, respectively.

  
Reference is now made to FIG. 16 which indicates that the volatile compound containing a metal can be introduced into the chamber 406 by circulating a gaseous vehicle from the reserve 611 in the line 612, after opening of the valve 613. The valve 614 adjusts the flow of the gas vehicle to the correct value indicated by the flowmeter 615.

  
The reservoir 617 contains for example a solution of the com-.

  
  <EMI ID = 91.1>

  
tetrahydrofuran. The gaseous vehicle passes through the bubbling tube 616 and into the solution of the reservoir 617. The valve 637 remains closed and the valve 634 remains open so that the gaseous vehicle, the solvent vapors and the vapors of the compound containing the metal are successfully directed. -

  
  <EMI ID = 92.1>

  
623, 607 and 633 and the distributor 635, all these materials mixing with the inert fluid and arriving in the chamber.

  
  <EMI ID = 93.1>

  
The volatile compound decomposes on contact with hot surfaces in the reactor. When it decomposes to form a pure metal, the oxygen or water vapor then enters chamber 406 and causes the oxide to form.

  
G, We now consider the devices for adjusting the various parameters.

  
FIG. 17 represents a device 700 for adjusting the temperature of the reactor. The heating elements 302a, 302b and 302c are schematically represented in a star circuit, one end of each element being connected to the central point 701 and the other to a branch 702a, 702b or
702c of a three-phase power supply 702. The connection point 701 corresponds to the three-phase connection ring 319 of FIG. 7C. The power supply 702 is connected to the current output 703 of a control 704 which is itself connected to a main three-phase power supply 705 and to a trip circuit 706. The main power supply 705 provides a current for heating the reactor advantageously at 440 V.

   A radiometer 708 placed in channel 441 of Figure 7B is focused on element 302c and creates a signal, usually expressed in millivolts, corresponding to the temperature of the heating element. A voltage-to-current converter
709 amplifies the signal from the radiometer and transforms it into an electric current. A control point 707

  
  <EMI ID = 94.1>

  
connected to a computer (not shown) and a recorder
710 giving a permanent recording of the temperature. measured by the radiometer 708 are all connected to the converter 709. An input signal line 713 connects a

  
input 711 of signals from the control 707 to a computer, not shown. Ammeters 750a, 750b and 750c are mounted in the three branches 702a, 702b and 702c and measure the current transmitted to elements 302a to 302c, and the volt-

  
  <EMI ID = 95.1>

  
give the voltages across the heating elements.

  
The energy dissipated in these and the electrical resistance thereof can be calculated from the voltage and current measurements. Knowing the electrical resistance of each heating element gives information about its physical integrity because? when the heating element erodes, its electrical resistance increases.

  
Fig. 18 is a graph showing the changes in laminar electrical resistance of a sample of graphite cloth (WCA graphite cloth of

  
Union Carbide Corporation) as a function of temperature

  
of the fabric, indicated on the abscissa. The fabric has been made rigid by pyrolytic graphite, by heating and exposure to a carbonaceous gas atmosphere, generally following

  
the method described above. The ordinates represent

  
the laminar resistance in ohms per square because we know that

  
the resistance measured between opposite edges of squares of a resistive material of given thickness does not depend on

  
dimensions of the square. Thus, the resistance at a particular temperature of a heating element formed from a single rectangular strip of the WCA fabric can be determined by considering the separation of the strip into squares of fabric connected in series. For example, the resistance of a 152.4 x 1295.4 mm strip at 1371 ° C, measured between the 152.4 mm sides, is obtained by multiplying by 1295.4 / 152.4 of 0.123 il which is the laminar resistance at 1371 [deg.] C given from figure 18. The resistance of a heating element having several layers of fabric of the same size and therefore of the same resistance is obtained by dividing the resistance d 'a single layer by the number of layers.

   For convenience, the laminar resistances calculated in ohms per square for the samples of WCA graphite fabric comprising 2, 3 and 4 layers are also given in Figure 18.

  
During operation, when control 707 has been set to a temperature setpoint, manually or

  
by a computer, it compares this with the measured temperature of the electrode 302c and transmits an error line

  
which depends on the algebraic difference between the measured and set temperatures. Control 707 sets trip circuit 706 which, depending on the error signal, causes the amount transmitted to the heating elements by the control to increase or decrease.
704 so that the magnitude of the error signal is reduced if necessary and the temperature of element 302c approaches the set temperature. As the element
302c is located in the cavity surrounded by the thermal shield 410, its temperature is generally representative of that of the surfaces of the cavity. However, radiometers focused on other surfaces of the black body can be used for temperature control.

  
FIG. 19 indicates that, in addition to the temperature, other parameters can be regulated by feedback control circuits, comprising for example a circuit 714 for regulating the flow of the main liquid reagent comprising a reserve 715 communicating with a circuit
716 dosing via a feed line 717. Circuit 716 regulates the flow rate of the main reagent and may include, for example, a variable speed pump and a pump drive or a variable orifice valve and a valve drive. An output 718 of circuit 716 is connected to a flow transducer 719 which creates an elec-tric signal 720 corresponding to the flow rate of the main reagent. An outlet 721 of the transducer 719 is connected to the piping
215 main liquid reagent inlet.

   A signal 722 from pressure gauge 654 and signal 720 from transducer 719 reach two signal inputs of circuit 716. A signal from computer 723 is transmitted to a third input of circuit 716.

  
In one mode of operation of the circuit 714 for regulating the flow rate of the main liquid reagent, the computer 723 transmits both a value. predetermined flow rate of the main reagent and an upper limit of the pressure in the reaction zone to circuit 716 which compares the predetermined flow rate to the flow rate measured by transducer 719 and adjusts the flow rate so that it approaches the selected value provided however that the pressure of the reaction zone is below the prescribed upper limit. When this pressure exceeds the upper limit, the metering circuit 716 reduces the pressure by reducing the flow rate of the main reagent.

  
A circuit 724 for regulating the flow of a secondary liquid reagent forms another reaction control circuit which comprises a reserve 725 communicating with a dosing circuit 726 via a supply line 727. Circuit 726 can be of the type described for circuit 716. An output 728 of circuit 726 is connected to a flow transducer 729 which creates a signal corresponding to the flow rate of the secondary reagent. An output 731 of the transducer 729 is connected to the input 221 of secondary reagent. A signal 722 from the pressure gauge 654 and a signal 730 from the trans-

  
  <EMI ID = 96.1>

  
726, and a signal from computer 723 arrives at a third input of this circuit. Device 724 can operate

  
Operate as described for device 714.

  
In a circuit 734 for regulating the flow of inert fluid, an outlet of the reserve 640 of inert fluid is connected to the valve 643 which is itself connected to the stop valve 642. The latter is connected to a trans-

  
  <EMI ID = 97.1> transducer 735 reaches a first input of a needle valve control 737. A second input of command 737 is connected to computer 723 and a third input to pressure gauge 646. The opening of valve 643 can be adjusted by command 637. Inert fluid from transducer 735 reaches inputs 408 and 409.

  
of the reactor. For convenience, valve 647, flowmeter 644, and distributor 635 in Figure 16 are not

  
not shown in figure 19, and transducer 735 of figure 19 is not shown in figure 16.

  
In operation, valve 642 is open and allows the passage of inert fluid into the transducer
735 and inputs 408 and 409. Command 737 compares the flow signal from transducer 735 to a specified flow rate.

  
by the computer 723 and adjusts the valve 643 accordingly provided, however, that the pressure detected by the pressure gauge
646 does not exceed a higher value specified by the calculator 723. When the pressure is excessive, the control 737 reduces the flow and thereby reduces the pressure.

  
A device 700 for adjusting the temperature of the

  
  <EMI ID = 98.1>

  
cally in Figure 19 comprises a temperature control 738 which comprises an energy control 704, a circuit
706, a set point control 707, a converter 709, a recorder 700, and ammeters and voltmeters 750 and 751, these elements being shown in Figure 17. The radiometer 708 (not shown in Figure 19) is housed in channel 441 and connected to control 738. Power supply 702 transmits energy 703 from control 738 to elements 302 (not shown in FIG. 19) through electrodes 309. Thus, the amount of electrical energy transmitted at output 703 determines

  
the temperature of the tube 401. The input 711 of control signals and an output of the control 738 are connected to the computer 723 by lines 713 and 712 respectively.

  
A reactor product sampling device 740, connected to an outlet 741 located near the valve 655t, transfers samples of the reaction products at predetermined intervals to an inlet 742 of a gas chromatograph 743. An electrical signal from an output 744 of the chromatograph 743 varies as the chemical composition of the samples varies. Thus, the chromatograph 743 and the device 740 can create a signal corresponding to the concentration of ethylene during the partial pyrolysis of a hydrocarbon.

  
Signals from the 743 chromatograph arrive at a

  
  <EMI ID = 99.1>

  
ci is connected to parameter transducers by a common data line 746 which includes signal lines connected to transducers 719, 729 and 735, manometers 646 and 654, control 738 and chromatograph 743. Other transducers may be connected to the common line
746 if applicable. An output 747 of the computer 723 is connected to a common control line 748 which includes signal lines connected to the circuits 716 and 726 and to the controls 738 and 737.

   The computer 723 may be a digital computer and may include an analog-to-digital converter transforming the analog signals from the transducers into digital values for the computer, a digital-to-analog converter for transforming the digital signals from the computer into analog control signals, and a Multiplexer for controlling the signal lines of the common lines 746 and 748.

  
According to the invention, during an operation, the computer 723 can specify and control parameters

  
using signals transmitted by common lines 748 and

  
746. Thus, the computer 723 can supervise the operation of the reactor so that the parameters remain within determined ranges. In addition, the computer can be programmed so that it searches for the optimum operating conditions for a particular operation by systematically varying the parameters and controlling the reactor output with the 743 chromatograph. Thus, the computer can be programmed so that it determines the reactor temperatures and feed rates which maximize the ethylene concentration for a particular hydrocarbon feed at the reactor outlet. The calculator 723 may also include feedback control circuits, for example a fractional product control circuit.

  
  <EMI ID = 100.1>

  
sampling, the chromatograph 743, the control 738 and the power supply 702 connected to the elements 302. In such a control, the computer compares the chemical composition of the samples of the reaction products withdrawn with a composition.

  
  <EMI ID = 101.1>

  
747, this signal corresponding to deviations or deviations in the chemical composition of the samples. The output 747 is connected to the input 711 of the reactor temperature control so that this temperature can vary as a function of variations in the signal from the computer, with a reduction in the variations in the chemical composition of the reaction products.

  
Other parameters, such as particular reactant flow rates and the pressure in the reaction zone, can be adjusted by reaction.

  
The chemical reactions at high temperature carried out according to the invention require the use of an inert fluid sheath or protection which is substantially transparent to radiation. The sheath or envelope has a significant axial length. This annular sheath can be created substantially parallel to the axis, or substantially perpendicular to its axis, towards the interior of the outer circumferential surface.

  
In the first case, as described in the first embodiment of the reactor, the fluid in the sheath must

  
be maintained as a laminar stream preventing mixing with the reactant stream. This criterion imposes certain limits on the axial length of the cladding given the laminar flow, and the integrity of the protection cannot be maintained over indefinite lengths downstream, especially when a particularly violent reaction is expected. Thus, such a method of creating the sheath is especially suitable for laboratory and small-scale applications.

  
In the last case described above, concern-

  
  <EMI ID = 102.1> tion, the integrity of the sheath or fluid shield is independent of flow considerations and can be maintained over an axial distance much greater than that obtained in the case of a laminar shield injected in parallel to the axis. The essential criterion is the maintenance of a stream of inert fluid at a pressure higher than that of the stream of reactant so that the reactants cannot pass through the fluid shield or no longer be confined? by the sheath.

  
When the sheath or shield has been created, a brake reagent passes through the center in a predetermined path which substantially coincides with the axis of the sheath.

  
This confines the reagents in and out of contact with the surfaces of the reactor chamber.

  
Finally, very intense radiation is transmitted to the center of the cladding and coincides with at least part of the predetermined path of the reagents. These radiations can be directed at at least one point of the path of the reactants as in the first or the third embodiment,

  
or over a finite length of this path as in the second and the fourth embodiment. In all cases, a sufficient quantity of radiation is absorbed in the central part so that the temperature of the reagents reaches the value necessary to trigger the desired chemical reaction.

  
When the reagents do not themselves absorb the radiation, an auxiliary absorbent material can be introduced along the path of the reagents, advantageously before directing the radiation in the central part. The auxiliary material then absorbs enough radiation so that the temperature in the central part reaches the value necessary to start the chemical reaction.

  
wanted. As indicated above, when the intended reaction is such that the transparent reagents create at least one radiation suppressant, the auxiliary material can be deactivated after initiation of the reaction.

  
The process under consideration may further comprise cooling the reaction products and the reagents and / or <EMI ID = 103.1>

  
desired tion. The purpose of this operation is to interrupt the desired reaction and to suppress any unwanted reaction. The remaining products, auxiliaries and reactants can be cooled advantageously and efficiently by radiative transfer to a cold radiation absorbing surface.

  
We now consider the implementation of re-. wall actors protected by a fluid. The reactors according to the invention can be used for practically all chemical reactions at high temperature, which have often been considered as impossible in practice or only theoretically.

  
  <EMI ID = 104.1>

  
The reason for such reactors in a particular chemical reaction at elevated temperature is that the reaction must be thermodynamically possible under the conditions considered.

  
When using these reactors, the chemical reactions considered can be carried out at temperatures up to about 3315 [deg.] C, by (1) creation inside the porous tube of the reactor of a tubular sheath of fluid inert transparent practically to radiation and forming a protection of the internal surface of the reactor tube, the annular sheath having a considerable axial length and

  
its internal part delimiting a reaction chamber, (2) circulation of at least one reagent (in the solid, liquid or gaseous state) in the reaction chamber along a predetermined path substantially coinciding with the longitudinal axis of the sheath, the reagents being confined in the room of

  
reaction, (3) direction of very intense radiations in the reaction chamber so that they coincide with at least part of the predetermined path of the reactants, a sufficient quantity of radiations being absorbed in the chamber so that the temperature of the reactants reaches the value necessary for triggering and maintaining the desired chemical reaction.

  
Among the reactions which can be carried out in the reactors according to the invention, there may be mentioned the dis sociation of hydrocarbons and of hydrocarbon materials. <EMI ID = 105.1>

  
gene and carbon black, the steam reforming of coal, petroleum fractions, oil shale, tar sands, lignite and other carbonaceous or hydrocarbon feedstocks in the form of synthesis gas mixtures, the processes also being able to understand the possible use of one or more mineral carbonates (such as limestone or dolomite) or mineral oxides which react chemically with the sulfur-containing impurities which can thus be removed from the mixtures formed of synthesis gas, the partial dissociation of the hydrocarbonaceous materials and hydrocarbons to lower molecular weight compounds, partial pyrolysis of saturated hydrocarbons to unsaturated hydrocarbons such as ethylene, propylene and acetylene,

   the conversion of organic wastes such as sludge from sewage or by-products containing lignin into fuel gases, the total or partial desulfurization of hydrocarbon feedstocks containing sulfur, the reduction of ores or organic compounds to a lower valence at using hydrogen, carbon, syngas or other reducing agent, and the total or partial reaction of an inorganic element or compound with a carbonaceous material to

  
that the corresponding mineral carbide is formed.

  
If desired, one or more catalysts can be added in these high temperature chemical reactions so that they accelerate the reaction or change its course.

  
to a desired sequence. When the process uses carbon or hydrocarbon reactants, the addition of a suitable catalyst to the system may promote the formation of free radicals, carbonium ions or carbanions influencing the course of the reaction.

  
Obviously, a single set of operating conditions is not optimal or suitable for all the reactions which may be carried out in the reactor. Operating conditions such as temperatures, pressures, feed rates, reactor tube residence time, and cooling rates can vary depending on the particular reaction being carried out. For example, among the parameters which have an influence on the products of the pyrolysis of a hydrocarbon, mention may be made of the heating temperature of the hydrocarbon and the holding time at this temperature. It is known, for example, that methar must be heated to approximately 1232 [deg.] C so that it forms acetylene. Formation of ethylene from ethane begins

  
at a relatively low temperature, of the order of 830 [deg.] C.

  
In an example of pyrolysis of hydrocarbons, acetylene, ethylene, hydrogen, carbon black and hydrocarbon oils are formed. Reaction times

  
of the order of a millisecond generally render maximum

  
acetylene yield, since reactions lasting longer than 1 millisecond generally favor the production of ethylene and other products to the detriment of acetylene, while reaction times less than 1 millisecond generally reduce the yield both ethylene and acetylene. Very high temperatures

  
  <EMI ID = 106.1>

  
production of carbon black and hydrogen to the detriment

  
acetylene and ethylene. The reaction times in the reactors of the invention can be reduced by shortening the reactor tube and by increasing the flow rate of the reagents introduced into the tube. For very short reaction times, mixing an auxiliary radiation absorbing material such as carbon black with

  
reagents may be advantageous so that the coupling between the stream of reagents and the radiation from the tube wall is promoted and thus facilitates the rapid heating.

  
pide of reagents.

  
We will now consider examples of the implementation of various chemical reactions at high temperature, in reactors with a wall protected by a fluid according to the invention. In all of these examples, the high temperature, fluid-walled reactor, shown in Figures 2A through 6, is used to carry out the particular reaction. Reactor tube 61 is a 91.4 cm long porous graphite tube having an internal diameter of 7.6 cm and an external diameter of 10.2 cm, the average pore radius being 20 microns. The porous tube is housed in a 25.4 cm diameter steel pressure vessel 70. Tube 61 is heated by electrodes 100a to
100f of carbon placed in the chamber 85. The thermal shield 120 also placed in the chamber 85 is made of molybdenum.

  
A water-cooled collar 125 is placed near the outlet end of tube 61 and cools the re-products.

  
  <EMI ID = 107.1>

  
Continuing from each example for a varying amount of time, tube 61 is inspected for the presence of an accumulation of carbon black or the like. We never discover

  
EXAMPLE 1

  
This example concerns the thermal dissociation of methane. A series of tests are carried out intended to determine the efficiency of the reactor according to the invention for the thermal dissociation of natural gas with variable flow rates and reaction temperatures. During all the tests, hydrogen is introduced into chamber 85 through the inlet

  
83 and it circulates through tube 61 into the reaction chamber at a constant flow rate of 141.5 l / min. The intensity of the current in the electrodes 100a to 100f is regulated; <1> so that

  
  <EMI ID = 108.1>

  
Drugs a small amount of carbon black into the reactor through inlet 121 at the same time to form an absorbent auxiliary material to initiate pyrolytic dissociation. When dissociation has started, the addition of additional black is not necessary for the maintenance of the reaction. Dense black smoke escapes from the outlet of the tube and is found to contain carbon black and hydrogen. The black particles are very fine and their filtration is very difficult. Spraying water into the effluent stream just above the outlet end of tube 61 makes it possible to agglomerate the black particles and collect them on a cloth dust filter. The following table indicates the percentage of dissociation for various flow rates included

  
  <EMI ID = 109.1>

  
between 1250 and 1871 [deg.] C, the fraction of dissociated methane being determined by measuring the thermal conductivity of the effluent gases after filtration of the carbon black particles of the sample.

BOARD

  

  <EMI ID = 110.1>


  
EXAMPLE 2

  
This example concerns the thermal dissociation of liquid hydrocarbons. A series of tests are carried out to determine the efficiency of the reactor of the invention for the thermal dissociation of liquid hydrocarbons. The shielding gas is hydrogen having a constant flow rate of 141.5 l / min. Liquid hydrocarbons chosen for the series of tests

  
are distillates obtained from crude oil and comprising naphtha (boiling point 38 to 93 [deg.] C), kerosene and diesel fuel (boiling point

  
  <EMI ID = 111.1>

  
boiling greater than 316 [deg.] C). The test results are as follows.

  
  <EMI ID = 112.1>

  
approximately in tube 61 at a rate of 0.19 l / on at inlet 121. The temperature of the tube is maintained at 1871 [deg.] C. Pure naphtha passes through the reactor unaffected because it is apparently transparent to thermal radiation from the glow tube. Naphtha is then rendered opaque by mixing with 0.1. by weight of finely divided carbon black. When this opaque mixture penetrates into the reactor as before, the coupling of thermal radiation is excellent. Carbon black and hydrogen escape from

  
the outlet of the tube. Analysis of the gas produced with a thermal conductivity cell indicates that it contains more than
98 mole% hydrogen, so that the dissociation is almost complete.

  
B. KEROSENE-DIESEL FUEL. This material is mixed with 0.1% by weight of carbon black and introduced into the reactor at a rate of 0.19 l / min. The tube of re-

  
  <EMI ID = 113.1>

  
carbon and hydrogen. Thermal conductivity measurements indicate that the effluent gas contains more than
98 mole% hydrogen,

  
C. GASOIL. We introduce diesel mixed with black

  
  <EMI ID = 114.1>

  
the tube is kept at 1871 [deg.] C, the gas oil dissociates into black and hydrogen, which is when separated from black, contains 98 mole% pure hydrogen, as indicated by thermal conductivity measurements. When the temperature of the tube is reduced to 1538 [deg.] C, the reactor effluent is no longer a dense black smoke but a light gray mist indicating that, at the lower temperature, the diesel is not

  
dissociates only partially presumably into light hydrocarbon fractions and a small amount of carbon.

  
D. RESIDUAL OIL AND ASPHALT. The residual oil containing the asphalt, introduced into the reactor at a rate of

  
  <EMI ID = 115.1>

  
by thermal conductivity of the gaseous component of the effluent stream indicates that the latter contains more than 98 mol 96 of hydrogen.

  
EXAMPLE 3

  
This example concerns the thermal dissociation of coal. We analyze a sample of fat coal from Utah <EMI ID = 116.1>

  
ashes. It is sprayed to a particle size less than 0.29 mm and introduced into the reactor at a rate of

  
  <EMI ID = 117.1>

  
carbon black, in gaseous products and in light coke.

  
The carbon black differs from that of Example 1 in that the particles are large enough to be filterable by adding water. Black contains 8.63% ash and 0.54% sulfur, by weight. The gaseous product is a mixture of hydrogen and nitrogen (the latter coming from

  
shielding gas), containing only 0.02 mole% sulfur, present in the form of hydrogen sulfide.

  
About 62% of the weight of the starting material is converted to coke. This is very light and open, its density being only 35% of that of the starting carbon.

  
When freshly prepared, coke oxidizes spontaneously in air to ash in less than 12 hours, indicating that its surface activity is high. When the coke remains at room temperature overnight in a nitrogen atmosphere, it exhibits more surface activity

  
and does not oxidize spontaneously on subsequent exposure to air. Microscopic examination of the body indicates that it comprises small hollow spherical globules of vitreous substance. Chemical analysis indicates that the coke contains 8.27% by weight of ash and 0.70% by weight of sulfur.

  
EXAMPLE 4

  
This example is for the. steam reforming and carbon gasification. A sample of coal from Carbon County, Utah, USA was analyzed which contained ash and high limestone content, and found to contain 0.60% sulfur. The coal is pulverized to a particle size of less than 0.29 mm

  
and it is introduced into the reactor at a rate of approximately 4.74 kg / h. Water vapor at 121 nC simultaneously enters the reactor at a rate of 9.08 kg / h. Tube 61 is held at

  
  <EMI ID = 118.1> a dense white vapor coming from the outlet of the reactor. It does not appear that carbon black or heavy residues were formed. No ash or other solids are found in the hopper which is just below the outlet of the reactor tube, so all of the solid residue from the coal is entrained in the product gas.

  
The solid products are separated from the effluent stream by filtration and the remaining gas is dried before analysis by a mass spectrometer. The results of the analysis, excluding air, are as follows (the concentrations being given in moles%): nitrogen 0.051%, carbon monoxide 7.563%, hydrogen sulfide absent, bisul-

  
  <EMI ID = 119.1>

  
The gaseous product of this reaction can be used

  
as fuel. Also, the analysis does not indicate any sulfur containing compounds, although the mass spectrometer can detect sulfur compounds at a concentration as low as 10 ppm. Thus, practically all

  
sulfur initially present in the coal was entrained in the solid particles removed from. effluent by filtration.

  
EXAMPLE 5

  
This example relates to steam reforming and gasification of oil shale. A sample of? Is sprayed to a particle size less than 0.147 mm. Green River bituminous slate obtained from a source near Rifle, Colorado, United States of America. The presence of various carbonaceous materials in the sample oil shale is determined. Methylene chloride extracted at room temperature 0.93% by weight of the shale. The sample is analyzed by heating a portion in air and observing the loss in weight as a function of temperature. The results of the analysis are as follows:

  

  <EMI ID = 120.1>


  
These measurements indicate that the oil shale contains 15% by weight of organic matter and 27.3% by weight of limestone.

  
  <EMI ID = 121.1>

  
a siliceous material.

  
The pulverized sample is introduced into the reactor at a rate of 17.25 kg / h. At the same time, water vapor enters the reactor at a rate of approximately 9.08 kg / h.

  
The water vapor is at 121 [deg.] C at the inlet of the reactor. The tube

  
  <EMI ID = 122.1>

  
the porous wall at a rate of 141.5 l / min and constitutes the gas shield. A stream of colorless vapor escapes from the outlet of the tube and has a temperature of 521 [deg.] C just below the outlet of the reactor.

  
Solid ash is also produced and falls into the hopper located under the tube. The ashes essentially contain molten glass beads of various colors. The material is analyzed to determine the residual carbonaceous material by spraying and determining the weight loss as a function of heating as performed on the original shale. No weight loss was observed on heating from 500 to 780 [deg.] C, indicating that no organic matter remained from the original shale in the ash. A weight loss of 14% is observed when heating the

  
  <EMI ID = 123.1>

  
calcium carbonate from the original sample remains in the ash and some of this calcium carbonate has undergone decarboxylation during the reaction. The treatment

  
  <EMI ID = 124.1>

  
evolution of hydrogen sulfide and carbon dioxide, indicating that the sulfur which may be present in the original sample is at least partly present in the ash.

  
The gaseous component of the reactor effluent is

  
  <EMI ID = 125.1> <EMI ID = 126.1>

  
acetylene, 0.39% ethylene, 1.24% nitrogen, 8.70% carbon monoxide, 0.04% 96 of various hydrocarbons, 0.016% carbon dioxide, 0.016% benzene, 0.002% toluene and less than 0.0005% hydrogen sulfide. This gas can be used as a low sulfur fuel.

  
EXAMPLE 6

  
This example relates to steam reforming and gasification of wastewater sludge. A sample of wastewater activated sludge from dried human waste mixed with a binder in the form of a siliceous clay and pellet was analyzed to a particle size of about 2 mm, and found to contain, as a percentage in weight,
33.21% organic carbon, 4.38% organic hydrogen, 6.04% organic nitrogen, 0.23% organic sulfur, 6.14% water and 50% mineral residue.

  
The sludge is introduced into the reactor at a rate of
24.5 kg / h. A total of 11.35 kg is added. Steam at 121 [deg.] C simultaneously enters the reactor at a rate of 25 kg / h, that is to say substantially double the stoichiometric ratio corresponding to the reaction of gas with water. Hydrogen is Injected through the porous wall at the rate of
141.5 1 / min. The temperature of the reactor is maintained at 2066 [deg.] C.

  
The reaction products are in the form of a dense, white mist and a solid residue. The latter, collected in a trap placed under the tube, weighs 6.81 kg and

  
  <EMI ID = 127.1>

  
following option (in percentage by weight): organic carbon
12.88%, organic hydrogen 1.69%, organic nitrogen 2.34%, organic sulfur 0.37%, trace water and mineral residue 83%.

  
Part of the reactor effluent is condensed in a liquid nitrogen trap. The sample collected in the room

  
ge is brought to room temperature and it is found that it comprises a liquid part and a gaseous part. The boiling point of the liquid is 100 [deg.] C, indicating that it is water. The gaseous component, which can be used as a low sulfur fuel, is analyzed by mass spectrometer and gas chromatograph and the com- <EMI ID = 128.1>

  
EXAMPLE 7

  
This example concerns the partial pyrolysis of a gas oil.

  
To show the use of the reactor according to the invention during the partial pyrolysis of petroleum distillates, a light lubricant or gas oil is treated. This particular petroleum distillate is characterized by the following range of distillations:

  

  <EMI ID = 129.1>


  
The diesel is introduced into the reactor tube in the form of a mist by atomization with a misting nozzle.

  
  <EMI ID = 130.1>

  
tion of the fluid wall. In addition, hydrogen is introduced at the inlet end of the reactor tube by the sweep gas inlet which drives the mist into the tube.

  
The tube is initially brought to 1871 [deg.] C, approximately 141.5 l / min of hydrogen entering the pressure chamber.

  
  <EMI ID = 131.1>

  
approximately entering through the scavenging gas inlet. The gas oil is then introduced into the tube at a rate of approximately 0.95 l / min, using 141.5 l / min of hydrogen forming the atomization gas. The temperature of the effluent stream just below the outlet of the reactor is set at approximately 438 [deg.] C by reduction. <EMI ID = 132.1>

  
the reactor is allowed time to stabilize under these conditions.

  
Samples of the effluent stream collected by three methods, namely (1) by passing part of the effluent stream through a liquid nitrogen trap and collecting a sample by freezing, (2) by pooling

  
  <EMI ID = 133.1>

  
Quide and (3) circulation of part of the stream in a condenser cooled by water and collection of a liquid fraction, are then collected. The collected material

  
  <EMI ID = 134.1>

  
and then collecting samples of the liquid phases and. vapor of this material at this temperature.

  
The liquid collected below the water-cooled condenser is characterized by the following distillation characteristics:

  

  <EMI ID = 135.1>


  
The sample of the liquid phase collected from the liquid nitrogen trap is dried to remove water therefrom and analyzed; it is found to contain the following materials: xylene, styrene, toluene, benzene, pentane, pentadiene, cyclopentadiene, butene, butadiene, propylene, methylacetylene, methylnaphthalene, naphthalene and higher molecular weight hydrocarbons. The gaseous component of the material collected in the liquid nitrogen trap is dried and analyzed by mass spectrometer and gas chromatograph. After correction taking into account the presence of air, it is observed that two samples of the gaseous component have the following average composition (in mole%):
hydrogen 88.23%, methane 4.62%, ethylene 3.09%, propylene 1.22%, acetylene 0.55 &#65533;, ethane 0.41%, butene 0.36%, ben-

  
  <EMI ID = 136.1>

  
toluene 0.02%.

  
EXAMPLE 8

  
This example relates to the partial steam reforming of a gas oil. A gas oil identical to that of Example 7 undergoes partial steam reforming in the reactor during two substantially identical tests. In each of the tests, the gas oil is introduced into the reactor in the form of a mist by atomization through a nozzle. Hydrogen forms the protective gas, the sweep gas and

  
  <EMI ID = 137.1>

  
of these functions.

  
During both tests, the tube is initially heated to 1816 [deg.] C and hydrogen enters through the sweep gas inlet and into the pressure chamber at the flow rates which are to be used substantially. The gas oil is then introduced into the reactor at a rate of approximately 0.95 l / min with water vapor at a rate of approximately 1.82 kg / min, corresponding to the carbon / water vapor molar ratio of approximately 1 , 0 / 1.6. Due to the thermal load of gas oil and water vapor, the reactor temperature drops to 1593 [deg.] C. The temperature of the effluent stream just below the outlet is approximately 454 [deg.] C. Samples were collected and processed as described in Example 7.

  
The liquid collected under the cooled condenser

  
by water in the first test has the following characteristics of distillation:

  

  <EMI ID = 138.1>


  
In the second test, a sample of the liquid component collected in the liquid nitrogen trap can reach 10 [deg.] C and is dried to remove water before qualitative analysis.

  
It is observed that the sample contains the following materials:
toluene, benzene, pentene, pentadiene, cyclopentadiene, butene, butadiene, naphthalene, xylene, styrene as well as higher molecular weight hydrocarbons. The part of the original sample from the liquid nitrogen trap which is volatile at 10 [deg.] C undergoes drying and analysis by gas chromatograph and mass spectrometer.

  
  <EMI ID = 139.1>

  
Carbon dioxide 0.37%, butane 0.25%, methylpentadiene 0.25%, cyclohexane 0.13% and toluene 0.04%.

  
EXAMPLE 9

  
This example concerns the thermal dissociation of sawdust. Sawdust which is a lignin-containing byproduct is thermally dissociated in tube 61 at
1871 [deg.] C, with the introduction of hydrogen under pressure through

  
  <EMI ID = 140.1>

  
re enters the reactor at a rate of approximately 27.7 kg / h. The products of pyrolysis are in the form of finely divided carbon black similar to that obtained by dissociation of methane, gaseous products from the dissociation of volatile compounds, and an open textured carbonaceous material in which the structure fiber of the original wood is practically intact.

  
EXAMPLE 10

  
This example relates to the preparation of abrasive based on silicon carbide from silica. Silica sand having a particle size between 0.29 and 0.147 mm is introduced into the tube 61 through the inlet 121 at a rate of

  
  <EMI ID = 141.1>

  
protective shealth. The powdered material which falls from the tube is collected in a hopper placed below.

  
The powdered product is abrasive enough that it easily scratched glass, this characteristic indicating that it contains silicon carbide. Examination of the powder shows that it comprises spheres of silica covered with an envelope of amorphous carbon and fine platelets of crystalline silicon carbide.

  
EXAMPLE 11

  
This example relates to the production of aluminum carbide. A stoichiometric mixture of aluminum powder and elemental carbon is prepared for the intended reaction:

  

  <EMI ID = 142.1>


  
The mixture is introduced into the reactor at a rate of approximately 4.54 kg / h. Tube 61 is maintained at 1871 [deg.] C and hydrogen passes through the porous wall of the tube at a rate of 141.5 l / oz.

  
The reaction gives an amorphous brown-gray material collected in a trap under the tube. A sample of this product

  
  <EMI ID = 143.1>

  
a gas which burns with the characteristic yellow flame of methane and indicates that the product and hydrochloric arid have exhibited the following reaction:

  

  <EMI ID = 144.1>


  
The sample dissolves completely in hydrochloric acid and forms a clear solution. Since the elemental carbon used as the starting material is insoluble in 0.1N hydrochloric acid, this reaction indicates that the aluminum and carbon have reacted quantitatively in the reactor to form aluminum carbide.

  
  <EMI ID = 145.1>

  
and heated until sublimation, in order to determine the possibilities of producing aluminum carbide in the reactor of the invention from aluminum chloride

  
and carbon. The aluminum chloride vapor mixes.

  
to a stream of oxygen and this stream passes over a bed of carbon black. An arc lamp is fccalized on the surface of the

  
carbon bed and heat part of the bed to 999 [deg.] C as indicated by an optical pyrometer. Small orange crystals form just downstream of the heated zone indicating that aluminum chloride has reacted with carbon and hydrogen with formation of aluminum carbide and hydrochloric acid following the reaction:

  

  <EMI ID = 146.1>


  
When the orange crystals are added to 0.1 N HCl, the crystals dissolve and a gas is released which burns with the characteristic yellow flame of methane.

  
As this process simulates the reaction which can be carried out in a reactor with a wall protected by a fluid, by reaction of aluminum chloride with carbon and hydrogen (produced by thermal dissociation of a gas or

  
of a liquid hydrocarbon), this behavior suggests a new method of making methane by (1) reacting aluminum chloride with an inexpensive hydrocarbon material to form aluminum carbide and hydrochloric acid, and (2 ) water cooling of the product

  
  <EMI ID = 147.1>

  
that hydrolyzes aluminum carbide with the formation of methane and aluminum chloride which can itself be recycled.

  
EXAMPLE 12

  
This example relates to the reduction of ferric oxide by hydrogen. Pure ferric oxide with a particle size of less than 0.147 mm is introduced into the reactor at a rate of 15.94 kg / h at the same time as hydrogen which passes through the porous wall at a rate of 141.5 l / min in order to show the usefulness of the reactor of the invention for the reduction of metal ores. Hydrogen is both

  
gaseous shielding and an iron oxide reducing agent.

  
The tube is maintained at 1871 [deg.] C as indicated by focusing an optical pyrometer at the glowing inner wall of the tube. The temperature of the reagents in the tube is determined to be 15100C with an optical pyrometer. It forms

  
a gray powder which .9, -assembles in the hopper placed under the tube. The temperature of the effluent stream just above

  
  <EMI ID = 148.1>

  
when freshly prepared. Observation of the powder under the microscope indicates that it comprises small spherical particles, indicating that the iron was in a molten state as it passed through the tube.

  
EXAMPLE 13

  
This example concerns the thermal dissociation of hydrogen sulfide and methane. Hydrogen sulfide is reacted with the carbon formed in situ by thermal dissociation of methane, in the reactor of the invention with formation of carbon disulfide and hydrogen. The tests are carried out at two different temperatures, 1635

  
  <EMI ID = 149.1>

  
by focusing an optical pyrometer on the incandescent reagents placed in the tube, the carbon particles originating from the dissociation of methane being the essential incandescent constituents of the reaction mixture. Hydrogen is driven out through the porous wall of the tube

  
at a rate of 141.5 l / min and constitutes the gas shield.

  
  <EMI ID = 150.1>

  
The gas mixture is at room temperature at the inlet of the tube. Carbon black is added forming an absorbent auxiliary material which initiates the reaction, and when the reaction is initiated it sustains itself and

  
Carbon black is no longer necessary.

  
Samples of the gaseous portion of the products from both tests were analyzed with a mass spectrometer.

  
The results of the analysis are shown in the following table, in mole%:

  

  <EMI ID = 151.1>


  
Although all of the above examples are carried out in the reactor shown in Figures 2A and 2B, even better results can be obtained with the reactor of Figures 7A to 7D, with suitable modifications if necessary for the treatment of solid feeds. The use of circuits for adjusting the various parameters enables optimum operating conditions to be obtained and maintained with precision. When the control circuits include a digital computer, the search for optimal conditions can be carried out automatically.

  
  <EMI ID = 152.1>

  
and shown only as a preferred example and that we can provide any technical equivalence in its constituent elements without departing from its scope.


    

Claims (1)

ABSTRACT The invention relates to: A. A high temperature, wall protected reactor by a fluid, of the type in which practically all the heat is transmitted by radiative coupling, characterized by the following points considered individually or in various technically possible combinations: 1. It includes a. reaction tube having one end inlet and an outlet end, the interior of the tube defining a chamber, the tube being made of a material substantially transparent to radiation and comprising an internal wall and an external wall which delimits an annular channel between them, a fluid substantially transparent to radiation circulating in the channel so that it cools the tube, a diffuser placed near the inlet end of the tube and intended to transmit a inert gas under pressure, practically transparent to radiation, so that the gas then has a substantially laminar flow axially in the reactor chamber and that it forms a protection of the internal wall of the tube, a device for introducing at least one reagent into the chamber through the end inlet end of the tube, the reagents being directed in a predetermined path axially relative to the tube and being demarcated practically in the center of the chamber out of contact of the inner wall of the. tube by the protective gas, and a source of radiation placed in a reflector placed outside the tube, the radiation being collected and focused by the reflector so that it is directed into the chamber in which they coincide with at least part of the path predetermined reagents. 2. It includes a tube having an inlet end and an outlet end, the inside of the tube delimiting a chamber, the tube being of a porous refractory material capable of emitting sufficient radiation so that the temperature of the reagents present in the tube is raised to a value sufficient to initiate and maintain the chemical reaction desired, the pores of the refractory material having a diameter such that an inert fluid can flow uniformly and with a flow rate <EMI ID = 153.1> tion from the internal surface of the tube, the inert fluid being pra-. tically transparent to radiation, a sealed tabular container under pressure surrounding the tube of the reactor and delimiting a chamber under pressure ie inert fluid between the tube and the container, the inlet and outlet ends of the tube cooperating in a sealed manner with the chamber under pressure, the pressure vessel having an inlet for inert fluid transmitted under pressure to the pressure chamber and circulating therein. continuation through the wall of the porous tube to the chamber of reactor, a device for introducing at least one reagent into the chamber of the reactor through the inlet end of the tube, the reagents being directed along a predetermined path axial relative to the tube and being delimited by the protection of <EMI ID = 154.1> chamber of the reactor and out of contact with the inner wall of the tube, an electrical device placed in the pressure chamber, at a certain radial distance from the tube, outside it, so that it heats the tube to a temperature at which the latter emits sufficient radiation for the desired chemical reaction to be initiated and sustained, the radiation being directed towards the center where it substantially coincides with at least part of the path of the reagents, and a circumferential heat shield placed in the container outside the heater so that it reflects radiation back to the reactor tube. 3. It comprises a reactor tube having an inlet end and an outlet end and the interior of which delimits a reactor chamber, the tube being made of a porous material substantially transparent to radiation, a device for introducing the reactor. an inert fluid under pressure in the reactor chamber through the wall of the porous tube so that this inert fluid forms a shield for the internal surface of the reactor tube, the inert fluid being substantially transparent to radiation, a device for introducing at least one reactant into the reactor chamber through the inlet end of the tube, the reactants being directed along a predetermined path axially relative to the reactor and being bounded by the inert fluid shield substantially in the center of the reactor chamber and out of contact with the. inner wall of the tube, and a radiation source disposed in a reflector - placed outside the reactor tube, the radiation being collected and focused by the reflector and then directed into the reactor chamber so that it coincides with a part at the less than the predetermined path of the reagents. 4. It includes a reactor tube having one end. inlet and an outlet end, at least a portion of the interior of the tube defining a reaction zone, the tube being of a fabric of fibrous refractory material capable of <EMI ID = 155.1> reactants in the reaction zone reach the value necessary to initiate and maintain the desired chemical reaction, the fabric having many pores in diameter such that an inert and practically transparent fluid to radiation can flow uniformly and in quantity sufficient through the wall of the tube so that it forms a protection of the internal surface of the tube, a pressure-tight tubular container surrounding the tube and delimiting a pressure chamber of inert fluid between the tube and the container, the ends of inlet and outlet of the tube cooperating in leaktight fashion with the pressure chamber, the pressure vessel having at least one inlet inlet for inert fluid directed under pressure into the pressure chamber and through the wall of the porous tube to the zone reaction, a device for introducing at least one reagent into the reaction zone through the inlet end of the tube, the reagents being directed along a predetermined path axially with respect to the reactor tube and being delimited by the inert protective fluid substantially at the bottom center of the reaction zone and outside contact with the inner wall of the tube, an electrical device placed in the chamber underpressure, radially outward from the reactor tube and intended to heat this tube to a temperature at which it emits sufficient radiation for it to initiate and maintain the desired chemical reaction, the radiation being directed into the zone .reactive so that it substantially coincides with at least part of the path of the reactants, and <EMI ID = 156.1> substantially surrounding the heating elements and the reaction zone so that it defines a cavity of a black body, the thermal shielding reflecting the radiation inwards, towards the reaction zone. 5. It further comprises a device for introducing an auxiliary radiation absorbing material into the chamber of the reactor, in coincidence with at least one point in the path of the reactants, a sufficient quantity of radiation being absorbed by the auxiliary material so that the temperature of the reagents reaches a value necessary for the initiation of the desired chemical reaction. 6. The auxiliary material is a liquid. 7. Auxiliary material is a gas which absorbs radiation from the electromagnetic spectrum between about 100 microns and <EMI ID = 157.1> 8. The auxiliary material is finely divided carbon powder introduced through the inlet end of the reactor tube along a predetermined path which coincides with the path of the reactants. 9. Auxiliary material is a solid element placed in the reactor chamber along at least part of the reactant path. 10. The solid element is carbon. 11. It further comprises a device placed in the reactor chamber in coincidence with at least part of the path of the reactants and intended to raise the temperature of the latter to a value necessary to trigger the desired chemical reaction. 12. The device for raising the temperature of the reagents comprises an electrically heated element. 13. The device for raising the temperature of the reagents comprises an electric arc. 14. the device for raising the temperature of the reagents comprises a flame. <EMI ID = 158.1> 16. The reactor tube is made of organic polymer. 17. The reactor tube is made of an inorganic salt. 18. Fluid is gas. 19. The fluid is liquid or gaseous water, heavy water, nitrogen, air or oxygen. 20. The source of radiation is a plasma arc, heated filament or seeded flame. 21. It also includes a cooling device <EMI ID = 159.1> of the reactor tube. 22. The diameter of the pores is between about 0.025 and 0.5 mm. 23. The porous material is graphite, carbon, sintered stainless steel, sintered tungsten or sintered molybdenum. 24. The porous material is thorium oxide, magnesium oxide, zinc oxide, alumina or zirconium oxide. 25. It includes a device for cooling the pressure vessel. 26. The pressure vessel cooling device comprises coils placed around the outer surface of the vessel. 27. The electrical tube heater comprises a plurality of electrical resistance heating elements disposed radially outside the tube and spaced around it. 28. The fibrous refractory material is graphite or carbon. <EMI ID = 160.1> refractory on parts of the fibrous refractory material <EMI ID = 161.1> black so that the stiffness of the fabric is improved. 30. The device for depositing a refractory lining comprises sensors for determining the difference in <EMI ID = 162.1> a dosing device intended to transmit a refracting agent <EMI ID = 163.1> closing the outlet of the reactor tube, the stream of inert gas containing the deposition agent being directed into the reaction zone, radially outward through the wall of the tube to the pressure chamber of inert fluid. 31. It comprises a device for increasing the diameter of the pores of the fabric so that the stream of inert fluid passing through the wall of the tube increases. 32. The device for increasing the diameter of the pores comprises sensors which determine the pressure difference between the pressure chamber and the reaction zone, and a metering device for delivering an etchant into the stream of inert gas. . 33. It also includes a device, intended to reduce the diameter of the pores in the fabric so that the flow of inert fluid through the wall of the tube is reduced. 34. The pore diameter reduction device includes sensors for determining the pressure difference between the pressure chamber and the reaction zone, and a metering device for delivering a refractory deposition agent to the inert gas stream. 35. The refractory deposition agent is carbon dioxide. 36. The refractory deposition agent is a volatile compound containing a metal. 37. Portions of the fibrous refractory material which are heated and exposed to the inert fluid have a coating of refractory oxide. 38. Refractory oxide is thorium oxide, magnesium oxide, zinc oxide, alumina or zirconium oxide. 39. It comprises a tubular bellows placed in an inlet assembly section of the pressure vessel, an end inlet end of the bellows being sealed to the inlet assembly section, and an outlet end of the bellows being sealingly secured to the inlet end of the reactor tube by a support ring d 'reactor tube inlet, the bellows being deformable so as to allow axial expansion and contraction of the reactor tube. 40. It comprises a device for applying an axial tensile force to the reactor tube. 41. It comprises a device for introducing a liquid reagent into the reaction zone of the tube, comprising a misting base placed in the tube near an inlet of the reaction zone, the liquid reagent and an atomizing gas being directed under pressure and being mixed in the nozzle, the liquid reagent being dispersed at the outlet of the nozzle in the form of a mist which absorbs the radiation. <EMI ID = 164.1> tubular attached to the nozzle and placed outside the latter, the axis of the cover being substantially parallel to that of the reactor tube. <EMI ID = 165.1> <EMI ID = 166.1> of the reaction zone. 44. The device for introducing a liquid reagent into the reaction zone further comprises a device for introducing a scavenging gas at the inlet end of the reactor tube, the scavenging gas directing the spray mist. liquid reagent to the reaction zone. 45. Part of the inside of the reactor tube, between <EMI ID = 167.1> a preliminary reaction zone into which the inert fluid is directed so that it forms a shield which facilitates the confinement of the reactants substantially in the center of the reaction zone and out of contact with the internal wall of the tube. 46. The device for introducing a solid reagent into the reaction zone of the tube comprises a helical feed screw which is mounted in an elongated tubular housing. so that it can rotate, a device for driving the screw in rotation, a hopper intended for the introduction of a ground solid reagent into the housing, a device for introducing a sealing fluid under pressure into the housing at a point which is located downstream of the hopper, and an outlet device intended to evacuate the reagent and the sealing fluid out of the casing at the inlet of the reactor. 47. The electrical device comprises a plurality of electric resistance heating elements made of a fabric of a fibrous refractory material placed circumferentially around the tube at a certain distance therefrom. 48. The fibrous refractory material is graphite or carbon. <EMI ID = 168.1> graphitic material. B. A countercurrent heat exchanger with variable profile, intended to cooperate with a high temperature reactor with a wall protected by a fluid, the heat exchanger. <EMI ID = 169.1> outlet, its inlet end being intended to be fixed to the outlet of the reactor so that it receives the products of the. high temperature reaction, the heat exchanger being characterized by the following points considered individually or in combination; 1. It comprises an inner tubular wall of refractory material, an outer tubular wall of refractory material, concentric with the inner wall and remote from it on the outside, a spiral partition formed of a refractory material and placed between the internal and external walls so that it defines an annular spiral coolant channel, and at least one cooling fluid inlet passing through the outer wall and communicating with the cooling fluid channel, this fluid being discharged at the outlet of the spiral annular channel near the inlet end of the heat exchanger. <EMI ID = 170.1> cooling fluid from the outlet of the annular channel to a pressurized inert gas chamber of the reactor. <EMI ID = 171.1> obtained with a high temperature reactor with a wall protected by a fluid according to point 4 of paragraph A, said apparatus being characterized by the following points considered in isolation or in various technically possible combinations: 1. It comprises a device for removing samples of the reaction products leaving the reactor, a reaction products analyzer comprising a sample input and a signal output, the analyzer comparing the chemical composition of the reaction products. the reaction to a predetermined composition and creating at its output an electrical signal corresponding to the differences between the chemical composition of the samples analyzed and the predetermined composition, and an apparatus for regulating the temperature of the reactor which comprises a control signal input connected to the signal output from the analyzer, and an output transmitting energy to the electrical heater of the reactor tube, the temperature of the tube varying with variations in the signal from the analyzer so that the gaps between the compositions are reduced. 2. The analyzer includes a gas pleat chromatograph connected to a digital computer. 3. The sample withdrawal device comprises a device for transferring samples to the sample inlet of the analyzer at predetermined time intervals. 4. The temperature control comprises a triode thyristor circuit, mounted in series with a three-phase power supply. D. A method of carrying out a chemical reaction at high temperature, characterized by the following points considered individually or in various technically possible combinations: 1. It comprises the formation of an envelope of refractory material intended to reflect radiations, the volume surrounded by the envelope constituting a cavity of a black body, the formation in this cavity of an annular sheath of substantially transparent inert fluid to radiation, the sheath having a significant axial length, the inside of the sheath defining a reaction chamber, the circulation of at least one reagent in the cavity of the black body. and in the reaction chamber tion along a predetermined path substantially coinciding. with the longitudinal axis of the sheath, the reagents being confined in the reaction chamber, and the direction of radiation very intense in the reaction chamber so that it coincides <EMI ID = 172.1> a sufficient quantity of radiation being absorbed in the reaction chamber so that the temperature of the reagents reaches the value necessary to initiate and maintain the desired chemical reaction. 2. It comprises the use of a high temperature reactor with a wall protected by a fluid in which substantially all of the heat is transmitted by radia-tif coupling, this reactor comprising a reactor tube having an inlet end. and an outlet end, the interior of the tube delimiting a reactor chamber, the tube being of porous refractory material capable of emitting sufficient radiation so that the temperature of the reagents present in the tube reaches a value necessary for the displacement and the l 'interview <EMI ID = 173.1> silencer having a diameter such as substantially inert fluid. transparent to radiation flows uniformly through the wall of the tube with a sufficient flow rate so that it forms a protection of the internal surface of the tube, a tubular and tight pressure vessel surrounding the reactor tube and delimiting between the latter and it even a pressure chamber of inert fluid, the inlet and outlet ends of the reactor tube cooperating in leaktight manner with the pressure chamber, the pressure vessel having an inlet inlet for inert fluid transmitted under pressure into the chamber. pressure chamber and through the wall of the porous tube to the chamber reactor, a device for introducing at least one reagent into the reactor chamber through the inlet end of the tube, the reactants being directed along a predetermined path, axially relative to the reactor tube, the reactants being confined by the inert fluid shield, substantially in the center of the reactor chamber and out of contact with the inner wall of the tube, a electrical device placed in the pressure chamber, at a certain distance outside the reactor tube, this electrical device being intended to heat the tube to a temperature at which it emits sufficient radiation for the desired chemical reaction to be triggered and maintained, the radiation being directed to the center of the reaction chamber and substantially coinciding with at least part of it. of the reagent path, and a circumferential heat shield placed in the pressure vessel, outside the heater, the heat shield reflecting radiation back to the reactor tube, the process comprising creating inside the porous tube an annular sheath made of an inert fluid practically transparent to radiation so that this fluid forms a protection for the internal surface of the tube, the annular sheath having a significant axial length, the inside of the sheath defining a reaction chamber, the circulation at least one reagent in the reaction chamber along a predetermined path coinciding substantially with the longitudinal axis of the sheath, the reagents being confined in the reaction chamber, and directing very intense radiation into the reaction chamber so that it coincides with at least part of the predetermined path of the reactants, sufficient radiation being absorbed in the reaction chamber for the temperature of the reactants to reach a necessary value the initiation and maintenance of the desired chemical reaction. 3. The annular sheath is created in a substantially <EMI ID = 174.1> laughing at the outer circumferential surface of the sheath. 4. Auxiliary radiation absorbing material is introduced along the path of the reactants prior to introduction of the reagents into the reactor tube, sufficient radiation being absorbed by the auxiliary material to bring the temperature at the center to the value required for the reactor. initiation of the desired chemical reaction. 5. The auxiliary radiation absorbing material is deactivated after initiation of the desired reaction. 6. Radiations are directed over a finite length the predetermined path of the reagents. 7. It includes the cooling of the products of the reaction <EMI ID = 175.1> of the reactor tube so that the desired chemical reaction is completed and an unwanted chemical reaction is not possible. 8. The reaction products and remaining reagents are cooled by radiative transfer to a cold radiation absorbing surface. 9. It further comprises introducing an auxiliary radiation absorbing material along the path of the reactants before introducing them into the reactor tube, the auxiliary absorbing material being cooled immediately thereafter. 10. Hydrocarbons or hydrocarbonaceous materials are dissociated in the form of hydrogen and carbon black. 11. Coal, petroleum fractions, oil shale, tar sands, lignite or other carbonaceous or hydrocarbonaceous feeds undergo reforming at the. vapor in the form of syngas mixtures containing carbon monoxide and hydrogen. 12. One or more inorganic oxides or carbonates are added to the reagents so that they react chemically with them. the sulfur-containing impurities so that these can be removed from the synthesis gas mixtures formed. 13. Hydrocarbons or carbonaceous material are partially broken down into compounds of lower molecular weight. 14-. Saturated hydrocarbons undergo partial pyrolysis with the formation of unsaturated hydrocarbons. 15. Organic waste material is transformed into a combustible gas. 16. A catalyst is added to the reactants so that it promotes the formation of free radicals, carbonium ions or carbanions during the reaction. 17. A hydrocarbon feed containing sulfur undergoes <EMI ID = 176.1> 18. Ores or mineral compounds are reduced to a lower valence by hydrogen, carbon, syngas or other reducing agent. 19. An inorganic element or compound reacts partially or in part with a carbonaceous material, forming a corresponding inorganic carbide.