FI64056B - FOERFARANDE FOER UTFOERANDE AV EN VID HOEG TEMPERATUR SKEENDE KEMISK REAKTION OCH REAKTOR FOER UTFOERANDE AV FOERFARANDET - Google Patents

Description

t --- -Γ ~ —1 Γβ1 .... ADVERTISEMENT] U PAGE A! SU r λ r \ r. f ^ '11' UTLÄGGNLINGSSKRSFT 6405.6 ^ (si) Kv.ik.3 / int.ct.3 B 01 J 19/08 FINLAND — FINLAND <**) Patenttlhakmnui - PKantamAknlnf 7 527 37 Q2) HakemiipiM — AneMinlnpdif 30.09.75 ίΡΠ 's> (23) AlkupOM — GHtlghetadag 30.09.75 (11) Tullut JulklMkai - Bllvlt offumllg 21.03.77

National Board of Patents and Registration (44) Nihtiviksipanor ia> <uuL | foreign date— η (ς is

Patent- and re-registered Ansdfcan utlagd och utl. * Krlften pubflceratf J '' 3 (32) (33) (31) Requested Interest * - Begird prlorltet (71) Thagaro Technology Company, 2712 Kelvin Avenue, Irvine, California 92705, USA (US) (72) Edvin M.alovich, Brea, California, USA (UC) (7 · +) Bt-'rggren Oy Ab, (5'4) Method for carrying out a high temperature chemical reaction and a reactor for carrying out the process -Förfarande för the reaction time and temperature of the chemical reaction and the reactor for the reaction

The present invention relates to gas or liquid wall reactors for high temperature chemical reaction processes, as well as to the various processes that can be carried out in these reactors, many of which processes have previously been impossible or only theoretically possible. Both gas or liquid wall reactors and the processes used in these reactors use radiation coupling as a heat source, the planned chemical reactions are kept isolated inside a protective gas or liquid cover or shell from contact with the reactor surfaces, thus providing a heat shield, "black body cavity". As used herein, the term "cavity of a black body" refers to a space that is substantially surrounded on a surface or surfaces and from which, ideally, no radiation can escape. In the case of the present reactor, the thermal shield is formed by the surface or surfaces surrounding the "black body cavity" and the material from which the heat shield is made acts as an insulator to prevent heat transfer from inside the black body cavity and must be able to withstand

2 64056

High temperature reactors are currently used in pyrolysis, thermolysis, dissociation, decomposition and combustion reactions with both organic and inorganic compounds. Substantially all such reactors transfer heat to the reactants by convection and / or conduction, but this property inherently causes two major problems that limit the nature and scope of the reactions to be performed. Both problems are due to the fact that in a conventional reactor that transfers heat to reactants by convection, the highest temperature in the system is inevitably at the interface between the inner surface of the reactor and the reactant flow.

The first problem is the limitations of the available reaction temperatures due to the strength of known reactor wall materials at elevated temperatures. The decreasing ability of these substances to maintain their cohesiveness at increasing temperatures is, of course, well known. However, because it is necessary for these materials to be heated in order to transfer thermal energy to the reactant stream, the reaction temperatures used have been limited by the temperature to which the reactor wall can be safely heated. This is particularly critical in cases where the intended reaction must take place at high pressures or must produce high pressures.

Another problem is inherent in the fact that the wall of a conventional reactor is at the highest temperature in the system and that convection / conduction heat transfer requires contact between the wall and the reactant flow. At such an elevated temperature, the reactor wall is an ideal although not the most desirable reaction point in the system and in many cases the reaction products accumulate on the wall. Such accumulation degrades the ability of the system to transfer heat to the reactants and this increasing thermal impedance requires a progressive increase in the temperature of the heat source to maintain the initial heat transfer rate to the reactant flow. It is apparent that as the accumulation increases, the required heat source temperature may exceed the reactor wall material's ability to withstand heat. In addition, when additional energy is needed to maintain the reaction, the process becomes less efficient both technically and economically. Thus, at a point where the planned reaction can no longer be maintained due to either heat transfer, material strength, or economic considerations 3 64056, the system must be stopped and cleaned.

Purification is usually accomplished by scraping the reactor wall or chemically burning off the deposits. Some continuous processes have attempted to scrape the reactor wall during the reaction. However, the scraping tool itself becomes hot, a reaction takes place and then needs to be cleaned. In any case, this downtime represents a significant financial loss. In many cases, another system is installed to minimize lost production time. However, such additional equipment usually involves a significant capital investment. Some high-temperature chemical reactors include a tube that is heated to a temperature at which its inner walls emit sufficient radiant energy to initiate and maintain the reaction. However, as in the case of conduction and convection-based reactors, reactions in which solids are captured usually result in an undesirable accumulation of product on the pipe walls, leading to reduced heat transfer and even clogging of the pipe.

The reactor disclosed in U.S. Patent 2,926,073 is designed to produce carbon black and hydrogen by pyrolysis of natural gas. The process is explained as continuous, but in practice the convection-based heat transfer principle with which the reactor operates causes difficult problems both in the maintenance and control of the reaction. Because the heated tubes in the reactor are ideal reaction sites, carbon often accumulates and occasionally clogs the system. However, a more difficult problem is the problem of thermal robbery, which can result in explosions. With respect to this condition, it has been found that during the pyrolysis of natural gas, the thermal conductivity of the gas phase suddenly rises to about five-fold to thirty-fold, depending on the composition of the gas. Because the temperature in a conventional convection reactor cannot be controlled with sufficient speed and accuracy to compensate for this phenomenon, in some cases the system becomes unstable and explosions can result. Such conditions are inherent in conventional reactors and so far no way has been found to avoid this dilemma.

U.S. Patent 3,565,766 represents a recent attempt to improve the quality of coal by pyrolysis. The disclosed system includes a plurality of hollow steel vessels that act as multi-stage flowable beds at successively rising temperatures up to about 871 ° C. Fluidization at lower temperatures is accomplished with an inert gas that can in itself supply heat, although external heating is designed. At higher temperatures, the fluidization is carried out with the overhead gas obtained from the final stage; and in the final step, the temperature is maintained by internal combustion of the carbon in air or oxygen. As the system is mainly based on heat transfer by covalence, it has many of the shortcomings and disadvantages already discussed above.

The apparatus for producing carbon black disclosed in U.S. Patent 2,032,358 includes a porous tube disposed in a heating chamber. The hot gas is directed from the external furnace to the chamber and is then forced through the wall of the porous tube to mix with the reactants. Thus, only the convection transfer of heat from the fluid to the reactants is used. This, together with the fact that there is no "black body cavity", makes it necessary for a large volume of fluid to flow through the heating chamber to compensate for the heat loss.

U.S. Patent 2,769,772 discloses a reactor for the heat treatment of fluids such as hydrocarbons, which reactor includes two concentric tubes placed in a flame-heated furnace. The reactants flow axially through a permeable inner concentric tube. The heat-transfer gas flowing in the reangas-like chamber between the concentric tubes is heated by contact with the outer wall. The fluids in the inner tube are heated by convection as the heat-carrying gas passes through the permeable wall and mixes with them. In fact, it is impossible to heat the inner tube without simultaneously heating the outer tube to at least the same high temperature.

The surface combustion cracking furnace of U.S. Pat. No. 2,634,282 uses a similar convection-based heat transfer gas principle as U.S. Pat. No. 2,769,772. The furnace includes a porous, refractory tube surrounded by a jacket. The combustible fluid from the annular chamber is forced through a porous wall inside the tube where it is ignited. However, it is apparent that the combustible fluid in the annular chamber will explode unless forced through the porous wall at a rate greater than the rate at which the flame travels back through the wall. Similarly, the temperature in the reangasmic chamber must be kept below the ignition temperature of the gas / air mixture. Combustion products from the surface flame mix with the furnace reactants, contaminating them and possibly reacting with them. Heat is applied to the reactants by conventional mixing of the combustion products and reactants.

U.S. Patents 2,670,272, 2,670,275, 2,750,260, 2,915,367, 2,957,753 and 3,997,730 disclose combustion chambers for producing titanium dioxide pigment by burning titanium tetrachloride in oxygen. In Patent 2,670,275, which is representative of this group, titanium tetrachloride is fired in a porous refractory tube. The inert gas is continuously diffused through the porous tube into the combustion chamber, where it forms a protective curtain on the inner surface of the tube. This gas curtain substantially reduces the tendency of the titanium dioxide particles to adhere to the reactor walls. Since the combustion of titanium tetrachloride is an exothermic reaction, no means are reserved for supplying heat to the reaction mixture as it passes through the tube. In fact, according to patent 2,670,275, it is advantageous to remove heat from the reactor chamber either by exposing the porous tubing to the outside air or by circulating liquid coolant through a coil placed around the porous tube.

In the process of the invention for carrying out a high temperature chemical reaction, the reactants are passed centrally through a reaction tube having a gas cladding formed to protect its inner wall by passing an inert gas substantially permeable to the reaction chamber , and the invention is characterized in that the reaction tube of refractory material is heated for at least a part of its length, the radiant energy being generally reflected towards the reaction tube at a distance from the surrounding heat shield, the substances in the reaction tube being heated by absorbing the radiant heat emitted by the reaction tube.

In the event that the reactants themselves are permeable to radiant energy, an absorbent target substance is introduced into the reactant stream. The target substance absorbs enough radiant energy to raise the heart temperature to the desired level. However, in some 6,6405 β cases, although the reactants are permeable to radiation, one or more of the reaction products may be an absorbent. In such a case, after the reaction is initiated, the target substance can be removed and the reaction continues. An example of such a reaction is the pyrolysis of methane to carbon and hydrogen.

Some reactions recover either partially or completely unless the reaction products are cooled immediately and rapidly. In these cases, it is further contemplated that cooling of the reaction products and any remaining target materials will be accomplished immediately upon completion of the desired reaction.

The high temperature gas or liquid wall reactor of the present invention transfers substantially all of the required heat to the reactants by radiation coupling.

The reactor comprises (A) a reactor tube having an inlet end and an outlet end, the interior of which forms a reactor chamber made of a porous refractory capable of emitting radiant energy, the pores of the refractory material having a diameter of the tube which allows sufficient inert flow to form a protective curtain on the radially inward surface of the reactor tube; (B) a fluid-bearing tubular pressure vessel surrounding the reactor tube and delimiting an inert fluid collection chamber between the reactor tube and the pressure vessel, the inlet and outlet ends of the reactor tube being tightly closed from the manifold chamber; supply means arranged and adapted to supply at least one reaction component to the reaction chamber at the inlet end of the reaction tube, the reactor comprising (D) an electric heater located in the collector chamber and radially spaced from the reactor tube, and (E) circumferentially heated located in a pressure vessel radially outside the heater, a heat shield adapted to reflect radiant energy to the reactor tube.

7 64056

Unlike conventional convection sectors, the present invention is based on radiation coupling to transfer heat to a reactant stream. The amount of heat transferred is independent of both the physical contact between the reactor wall and the flow and the amount of vortex mixing in the flow. The main factor in heat transfer in the present system is the radiation absorption coefficient (a) of the reactants. The curtain of inert fluid which protects the reactor wall is preferably substantially permeable to radiation and thus has a rather low value of the factor (a). This allows energy to be transferred through the envelope to the reactant flow with little or no energy loss. Ideally, either the reactants themselves or the target material have high values of the factor (a) and thus absorb large amounts of energy, or alternatively, the reactants may be finely divided, such as in fog, so that the radiation is absorbed by being trapped between the particles. Because substances that are good absorbers are generally good emitters of radiation when the reactants or target substances are raised to a sufficiently high temperature, they become secondary emitters that re-radiate energy throughout the reactive volume and further improve the heat transfer properties of the system. This happens almost momentarily and can be monitored quickly and accurately. In addition, the re-radiation phenomenon, which ensures rapid and uniform heating of the reactants, is completely independent of the amount of turbulent mixing that can occur in the reactant flow.

The present high-temperature chemical process and equipment provide a solution to the problems that have plagued the industry and thus allow reactions to be carried out which have hitherto been impossible or only theoretically possible. Since the heat is supplied by radiation coupling and not by convection and / or conduction, the temperature of the reactant flow can be independent of both the reactor wall temperature and the conditions in the reactant flow, and a difficult strength problem of materials is avoided.

Although a heated wall is used as a source of radiant energy, high pressures are not used, which normally promote a wide variety of reactions. For this reason, 8,64056 refractories such as carbon or thorium oxide which are not suitable for use as a wall material in a conventional reactor can be successfully used. Compared to the most temperature resistant alloys that melt at about 1590 ° C, for example, thorium oxide is useful at temperatures above about 2930 ° C. This property allows much higher reaction temperatures than have hitherto been achievable, and reactions which have only been theoretically feasible can be carried out.

Carbon fabric, a preferred refractory for one embodiment of the present reactor tube, is relatively inexpensive, readily available, and can be formed into substantially larger reactor tubes than those currently available from cast porous carbon. Because carbon fabric is normally flexible, attempts to force an inert gas radially inwardly through a reactor tube of such a material would cause the tube to collapse. Accordingly, in accordance with the present invention, it is contemplated to deposit a layer of pyrolytic graphite on the fabric to stiffen it sufficiently to withstand the pressure difference maintained between the inert fluid-containing collector chamber and the reaction zone. Placing a pyrolytic graphite layer on the fabric also allows the porosity of the fabric to be adjusted.

The use of a protective inert fluid curtain, made possible by the use of radiation coupling, isolates the reactor wall from the reactant flow and makes it impossible under normal operating conditions for any precipitate or other deposit to accumulate and cause the system to become clogged. In the case of using a corrosive fluid such as steam as a curtain, the surfaces of the reaction tube, heating elements and heat shield kept at high temperatures and in contact with the curtain gas while the reactor is operating can be coated with a thin layer of refractory oxide such as thorium oxide or magnesium oxide. The refractory oxide can be deposited on these surfaces by heating the reactor above the dissociation temperature of the volatile metal-containing compound, introducing this compound into the reactor chamber and allowing it to dissociate, depositing the metal layer on the heated surfaces. A gas or other suitable substance such as molecular oxygen can then be introduced into the reaction chamber to oxidize the metal layer to form the desired refractory oxide. Alternatively, a refractory coating can be provided in one step if a volatile metal-containing compound that pyrolyzes directly to an oxide is used as the refractory deposition agent.

The use of radiation coupling still makes it possible to precisely and almost instantaneously control the heat transfer rates, which is impossible to achieve in a conventional convection reactor. In one embodiment of the invention, which is suitable for large scale commercial purposes, a power density of about 180 W / cm has been achieved. This figure represents a large improvement over 2-3 W / cm, which is usually achieved in conventional reactors. And the use of a heat shield to form the surface or surfaces in the cavity of the black body within which the reactions take place makes it possible to achieve unusually advantageous thermal efficiencies.

The reactions that can be carried out with the process and reactor of the present invention are many and varied. For example, organic compounds, especially hydrocarbons, can be pyrolyzed to produce carbon and hydrogen without the accumulation and thermal robbery problems encountered in the prior art. Saturated hydrocarbons can be partially pyrolyzed to give unsaturated hydrocarbons; thus, for example, propane and ethane can be dehydrated to propylene and ethylene. Unsaturated hydrocarbons can be partially pyrolyzed in the presence of hydrogen to form saturated hydrocarbons and, in particular, petroleum products can be thermally cracked.

Thus, gas oil can be easily converted to diesel oil, fuel oil (kerosene), gasoline fractions or even methane. Halogen additives can be added to partially pyrolyzed hydrocarbons to produce higher molecular weight compounds. Hydrocarbons can be completely or incompletely pyrolyzed in the presence of water vapor to form carbon monoxide and hydrogen; more hydrogen can then be added and the reaction continued to form alkane series hydrocarbons, which are high calorific fuel gases.

Inorganic compounds can also be pyrolyzed. For example, salts or oxides of iron, mercury, tungsten, and tantalum, among others, can be dissociated to obtain 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 results. This list is by no means intended to be exhaustive.

New mixed products can also be made by the present process. For example, carbon or talc particles coated with silicon carbide can be obtained. This product acts as an excellent abrasive because, as used, it constantly crumbles and forms new sharp surfaces. Certain elements, such as, for example, U particles, may also be encapsulated in a chemically sealed shell of another substance, such as carbon; in particular, the latter product is useful as a fuel element for a nuclear reactor.

We have further contemplated that the present invention may form the final step in conventional aerobic incineration of waste and wastewater. The relatively low temperatures that occur in current combustion technology allow the formation of organic nitrogen peroxides and oxides, which are major factors in causing photochemical smog and other types of air pollution. Because such compounds are not stable at the higher process temperatures provided by the present invention, waste incineration materials that are very low in contamination can be obtained.

11 64056

Further, the present invention includes high temperature anaerobic distillation and / or disassociation of wastes to yield useful products such as carbon black, activated carbon, hydrogen and broken glass, to name a few. The addition of water vapor to such waste produces carbon monoxide and hydrogen, which can then be processed in a conventional manner to produce combustion gases. Finally, the addition of hydrogen to such waste produces petroleum equivalents of heavy oils and other petroleum products. Thus, a substantial reduction in air pollution as well as significant economic gains can be achieved with these disclosed embodiments of the present invention.

The present invention represents a major breakthrough in the art. Because it makes it possible for the first time to use a source of thermal energy that has never been harnessed in this way before, its potential applications are numerous and varied. In addition, by avoiding the material strength problems that have limited the technique for many years, the present invention enables in practice many useful chemical reactions that have long been known but could not be performed due to the temperature limitations inherent in convection and / or conductivity reactors. heat transfer.

The invention will now be described with reference to the accompanying drawings.

Figure 1A shows a section of the inlet end of a reactor according to the present invention.

Figure 1B is a sectional view of the reactor outlet; Figures 1A and 1B show halves of a unitary structure divided along line A-A for the purpose of making the figures large enough to clearly illustrate certain structural details. Figure 1C is a partially sectioned perspective view of the reactor, with some parts removed or some parts schematically illustrated to more clearly illustrate the operation of the reactor. Figure 2 shows a section substantially along line 3-3 in Figure 1A.

Figure 3 shows a section substantially along line 4-4 in Figure 1B.

i2 64056

Figure 4 shows a section substantially along line 5-5 in Figure 1A.

Figure 5 is a perspective view of a portion of the reactor tube heating means in another embodiment of the present invention.

Figures 6A, 6B, 6C and 6D together form a partially sectioned front view of a reactor according to the present invention; the unitary structure of the reactor is divided along lines A-A, B-B and C-C in order to make the scale large enough to clearly show certain structural details. Figure 7 shows a section substantially along line 8-8 in pattern 6A.

Figure 8 shows a section substantially along line 9-9 in Figure 6B.

Figure 9 shows a section substantially along line 10-10 in pattern 6B.

Figure 10 shows a section substantially along line 11-11 in pattern 6C.

Figure 11 shows a section substantially along line 12-12 in Figure 6C.

Figure 12 shows a vertical section of a reaction finishing apparatus in an alternative embodiment of a reactor according to the present invention.

Figures 13A and 13B together form a partially sectioned view of an input composition of an alternative embodiment of the invention; the uniform structure of the input composition is divided along the line D-D in order to make the scale large enough for the clear presentation of certain structural details.

Figure 14 is a schematic diagram of a reactor according to the invention together with an apparatus for pretreating and introducing solid reactants into the inlet composition of the reactor according to the invention. Kuyio 15 is a schematic representation illustrating a refractory coating and etching system for a reactor according to the invention.

Figure 16 is a diagram of the temperature control circuit of a reactor according to the invention.

Fig. 17 is a graphical representation of the electrical resistance of the heating element of a reactor according to the invention as a function of temperature and depending on how many layers of refractory fabric form the element.

Figure 18 schematically shows the operation of different control systems of a reactor according to the invention.

i3 64 05 6

The invention considers black radiation or other electromagnetic radiation, in particular in the wavelength range of about 100 to 0.01 microns, to be the main energy source on which the design must be based.

Figures IA-5, and in particular Figures 1A-1C, illustrate a reactor 60 according to the invention, comprising a reactor tube 61 having an inlet end 62 and an outlet end 63; the interior of the tube 61 defines a reactor chamber 65 · The reactor tube 61 is made of a porous material capable of emitting radiant energy; the pore diameter is preferably about 0.02 to 0.5 mm to allow a uniform flow of sufficiently inert fluid through the wall of the tube to form a suitable protective curtain. Fiber wall constructions such as mesh, strainers or different types of perforations can also be used to achieve the desired result. Reactor tube 61 may be made of materials such as graphite, carbon, sintered stainless steel, sintered tungsten or sintered molybdenum, and inorganic materials such as oxides of sodium, magnesium, zinc, aluminum, or zirconium, among others. Tungsten, nickel and molybdenum are also suitable for use as nets or screens.

A fluid pressure vessel 70, preferably made of stainless steel, encloses the reactor tube 61. The integrity of the vessel 70 is maintained by a plurality of sealing flanges 71, 72; 73, 74; and 75, 76 connecting the various parts of the reactor 60 to each other. Flanges 72, 73 and 76 are further grooved to receive stainless steel O-rings 77 * 78 and 79 * which act as pressure seals. The reactor tube 61 is slidably mounted so that the other end is in a graphite sleeve 8l, which allows the tube 6l to be possibly elongated during operation at elevated temperatures.

The pressure vessel 70 further includes an inlet 83 for introducing an inert fluid, which material 6405 6 is substantially permeable to radiant energy. The inert fluid is substantially permeable to radiation because it has a low (a) value. Fluids suitable for this purpose include simple gases such as helium, neon, argon, krypton, and xenon; technical gases which do not decompose to form a solid product such as hydrogen, nitrogen, oxygen and ammonia; and liquid or gaseous water. As used herein, the term "inert" includes two factors: the ability of the fluid to chemically react with the material in the reactor tube 11 and the ability of the fluid to chemically react with the materials involved in the process. Thus, the choice of fluid in an inert curtain in each case depends on the environment. unless otherwise specifically designed, it is desirable that the fluid be inert to the reactor tube and it is usually desirable that the fluid be inert to the reaction being carried out, however, in some cases it may be thought that the "inert" fluid of the protective curtain also participates in the reaction. , such as when iron or carbon particles are reacted in the presence of a steam curtain to produce iron oxide and water or carbon monoxide and water. The inert fluid is first directed under pressure into a collector chamber 85 bounded between the reactor tube 6l and the pressure vessel wall 70. This fluid is then directed through the porous wall of the tube 61 into the reactor chamber 65 to form a protective curtain on the radial inner surface of the reactor tube 6l.

The means for cooling the pressure vessel 70 includes cooling coils 87 located around the radially outer surface of the pressure vessel. The coils 87 are preferably covered with a flame-sprayed aluminum coating, which improves thermal contact between the vessel 70 and the coils 87 to increase cooling efficiency. These coils 87 are also placed around the inspection opening 88 with which the wall of the pressure vessel is provided.

As best seen in Figures 1A and 2, the roactants are introduced into the reactor chamber 65 through the inlet end 62 of the reactor tube 61. The means for introducing the reactants include an inlet portion 90 mounted on a fluid retaining flange 71, 72 154056 adjacent the inlet end 62 of the tube 6l. The reactants are conveyed in a gas flow through the inlet 91 »past the tangential baffle 92 and to the collector chamber 93» bounded between the outer wall 94 and the diffuser 95. Suitable materials for the diffuser 95, which is designed to minimize turbulence in the flow, include porous carbon, steel wool, and a mesh screen. The reactants are directed to a predetermined path axially to the reactor tube 61 and are substantially bounded by a protective curtain in the middle of the reactor chamber 65 and away from contact with the inner wall of the reactor tube.

The reactor tube 61 itself generates high power radiant energy which is directed to its center to substantially hit at least a portion of the reactor path. Heating is provided by a plurality of carbon electrodes 100a-100f located radially outside the tube 6l and spaced from its circumference; the heat generated by the electrodes 100 is transferred to the tube 6l by radiation. As best seen in Figures 1A, 4 and 5, for example, the electrodes 100a and 100b are embedded at one end in a curved transverse carbon element 101a; electrodes 100c and 100d are embedded in the transverse element 101b; and the electrodes 100e and 100f are similarly embedded in the transverse element 101c. The tubular alumina spacers 101a-102c have the dual function of firstly interrupting the porous reactor tube 6l and secondly dividing the three circuits. As can be seen in particular from Figures 1B and 3, each carbon electrode is mounted at one end on a copper collector electrode 104. Although the reactor has six such electrodes 104, only one of them is shown in Figure 3 for clarity. Each copper collector electrode 104 includes a phenolic flange 105 and a ceramic insulator 106. The electrode 104 is cooled by water circulating in the inner channel 107, entering through the inlet 108 and exiting through the outlet 109. The high current electrical connection is indicated by reference numeral 110. The polytetrafluoroethylene gasket 111 helps to prevent leakage from the pressure vessel 70. The electrical system shown here is particularly suitable for use with a three-phase power supply. However, other systems may be used if circumstances so require. In addition, it is thought that the porous tube 6l itself can be heated directly by an electric resistor; in this case, the electrodes 100 may be omitted.

16 64056

The thermal efficiency of the tube heating means has been further improved by using a molybdenum heat shield 120 which forms a limiting surface for the “black body cavity” reflecting electromagnetic radiation from the carbon electrodes 100 toward the porous tube 6l. Because the heat shield 120 reflects and does not transfer heat, it acts as an insulator and thus can be made of any material that has this property and is capable of withstanding the temperatures generated by the electrodes 100. The heat shield 120 is positioned within the pressure vessel 70 radially outward from the electrodes and preferably consists of a flat strip of rectangular cross-section twisted into place in a plurality of helical turns. Such a construction allows inert gas to enter through inlet 83 and allows gas to circulate freely through the entire collection chamber 85.

The targeting agent or other initiating means or means may be used as needed. If the reaction components themselves do not have a relatively large radiation absorption component, the target substance can be introduced into the reactor chamber 65 via inlet 121. The target material may be a finely divided solid, such as carbon powder or other suitable material, which enters the reactor chamber 65 together with the reactants through inlet 62 and absorbs sufficient radiant energy to raise the temperature of the reactants to the required level. Alternatively, the target material may be a liquid such as tar, asphalt, linseed oil or diesel oil and may contain solutions, dispersions, gels and suspensions prepared in a variety of ways and readily selected from available materials to suit the particular requirements. The target substance may be a gas which preferably has an absorption in the range of about 100 to 0.01 microns of the electromagnetic radiation spectrum] such gases include, for example, ethylene, propylene, oxides of nitrogen, bromine, chlorine, iodine and ethyl bromide. The target may also be a solid element made of a material such as carbon placed in the reactor chamber 65 along at least a portion of the reactor path.

17 64056

Other means for raising the reaction temperature to the required level may include an electric heating element, an electric arc, or a flame disposed in the reactor chamber 65 to coincide with at least a portion of the reactant path. In these cases, the initial heat source is self-sustaining and is not derived from radiant energy generating means. Such devices are particularly useful when the self-reactants are permeable to radiation, but at least one of the reaction products is an absorber. Thus, once the intended reaction has begun, the temperature raising means can be deactivated because the reaction products absorb sufficient radiant energy to maintain the reaction. Similarly, if a target is used, its use can be stopped or withdrawn after the reaction has begun, the cleavage can take place, for example, by control means 35. An example of a reaction in which the target or other initiator is only needed initially is pyrolysis of methane to produce carbon and hydrogen. Cooling means 125 for reaction products having a construction as described above or some other suitable construction may also be used to prevent undesired chemical reactions that could occur if the reaction products were not cooled immediately after their formation.

18 64056

Since the radial introduction of the curtain does not require laminar flow of the curtain fluid, relatively large axial lengths of the reaction chamber can be achieved. All that must be done is to keep the absolute pressure level of the inert fluid higher than the absolute pressure level in the reactant flow in order to prevent the reactants and / or reaction results from colliding with the reactor tube 6l. This feature helps to make this embodiment more suitable for large-scale commercial operations.

The tube 61 in Fig. 1 must be heated and can operate at temperatures above 2930 ° C, as in the case of porous thorium oxide, for example. Although the cool wall is better able to withstand pressure because it is not under thermal stress, the hot wall 61 is not under the influence of a pressure gradient except perhaps under a relatively small difference between the fluid curtain and the reactant flow. The pressure is received by the wall of the stainless steel pressure vessel 70, which is naturally cooled by the coils 87 and is thus not subjected to thermal stresses. Accordingly, a refractory material, such as carbon or thorium oxide, which can withstand temperatures well above those that conventional reactor wall materials can withstand, but which are unsuitable for use in a conventional convection reactor, can now be used for the first time to provide a practical, ultra-high temperature system.

Figures 6A-14 show an embodiment of a high temperature chemical reactor according to the present invention with an improvement over the previous embodiment, comprising an inlet composition 200, an electrode composition 300, a main composition 400 and a reaction post-treatment composition 500. The main elements of this reactor include: 19 64056 (A) * 101 having an input end 402 and an output end 403; at least a portion of the interior of the tube 401 defines a reaction zone 4o4. The reactor tube 401 is made of a fibrous refractory fabric capable of emitting sufficient radiant energy to raise the temperature of the reactants in the reaction zone 404 to a level required to initiate and maintain the desired chemical reaction. The fabric may have a plurality of pores of a diameter such that the fabric allows a uniform flow of a sufficiently inert fluid substantially permeable to radiant energy to form a protective curtain on the radially inner surface of the reactor tube 401.

(B) A fluid-containing tubular pressure vessel (having an inlet portion 201, an electrode portion 301, a main portion 405, and a post-reaction treatment portion 501) encloses the reactor tube 4.01 defining an inert fluid collection chamber 406 between the reactor tube 401 and the pressure vessel. The inlet and outlet ends 402 and 403 of the reactor tube 401 are hermetically sealed from the manifold chamber 206 64 05 6 406. The pressure vessel has a first inlet 4o8 and a second inlet 409 to allow inert fluid to enter the manifold chamber 406 and the porous tube wall 401 under pressure.

(C) Means for introducing reactants, gaseous, liquid or solid into the reaction zone 404 through the inlet end 402 of the reactor tube 401. The reactants are oriented along a predetermined axial path of the reactor tube 401 and are enclosed by a protective curtain, and are substantially central in the reaction zone 404 and away from contact with the inner wall of the reactor tube 401.

(D) Electrical means including heating elements 302a, 302b and 302c located within the collector chamber 406 and radially spaced outward from the reactor tube 401 to heat the reactor tube to a temperature level at which it emits sufficient radiant energy to initiate and maintain the desired chemical reaction. The radiant energy is directed to the reaction zone 404 to substantially hit at least a portion of the reactor path.

(5) A heat shield 410 located within the pressure vessel substantially enclosing the heating elements 302a, 302b and 302c and the reaction zone 404 defining a cavity of the black body. The heat shield 410 reflects the radiant energy inwardly toward the reaction zone 404.

A. Entrance section

In particular, Figures 6A and 7 show a pressure vessel inlet assembly 201 which is a tubular member having first and second flanges 202 and 203 at its ends. An annular nozzle block 204 is attached to an annular sealing flange 205 which in turn is fluidly attached to the first pressure vessel outlet 201. 202. The main atomizing gas inlet pipe 206 extends through the annular nozzle block 204 and is fixedly attached thereto by a support flange 207. A sealing ring 209 in the support flange 207 ensures a fluid-tight seal between the main atomizing gas inlet pipe 206 and the flange 207. The inlet fitting 210 is attached to one end of the main atomizing gas inlet pipe 206, as shown in Figure 6A. The atomizing gas enters the collector chamber 211 through the inlet 212.

21 64056

The main inlet tube 214 of the liquid reactant is located inside the main atomizing gas inlet tube 206 and is substantially coaxial therewith. The main liquid reactant enters the tube 214 through the inlet 215 of the connector 210.

As best seen in Figure 6b, the spray nozzle 216 is attached to the outlet end of both the main spray gas inlet tube 206 and the liquid reactant main inlet tube 214. The spray nozzle 216 includes a tubular shell 217 mounted and located radially outward from the nozzle as shown. The axis of the shell 217 is substantially parallel to the axis of the reactor tube 401. In operation, the liquid reactant and atomizing gas are directed under pressure through tubes 214 and 206 and mixed under pressure in nozzle 216. The liquid reactant thus disperses from the outlet of the nozzle as a mist which absorbs radiant energy. The purpose of the tube 217 is to help the liquid reactant · mist remain centrally within the pre-reaction zone 411 of the reactor tube 401.

As best shown in Figures 6A and 7, the inlet portion of the preferred embodiment of the present reactor may further include a plurality of secondary inlet tubes 218a, 218b and 218c that allow the introduction of additional liquid reactants. The means for introducing the secondary liquid reactants are structurally and functionally similar to the means for introducing the primary liquid reactant described above and thus further comprise secondary atomizing gas inlet tubes 219a, 219b and 219c and atomizing nozzles such as 220a (no additional atomizing nozzles shown). A typical inlet for a liquid secondary reactant and a typical inlet for a secondary atomizing gas are denoted by reference numerals 221 and 222.

In the above, it has been assumed that the reactants themselves either have a relatively high radiation absorption coefficient (a) or can be converted into a mist that absorbs radiation energy. However, if this is not the case, a radiant energy absorbing target material, such as that previously described, must be introduced into the reactor zone 404 in coincidence with at least a portion of the reactant pathway. In particular, it can be seen from Figure 6a that the sweep gas helps to direct the liquid reactant mist towards the reaction zone 404.

22 6 4 0 5 6

The sweep gas enters the nozzle block 204 through the sweep gas inlet 225 »passes through the channel 227 and is directed axially towards the pre-reaction zone 411 of the reactor tube 401.

As shown in Figures 6A and 7, the reaction viewing aperture 226 provides an axial view of the reaction zone 404.

B. Electrode combination

In particular, it can be seen from Figures 6B, 8, 9 and 10 that the tubular pressure vessel electrode portion 301 has first and second flange portions 303 and 304 (Figure 6A). The electrode part 301 of the pressure vessel is fixed by its first flange 303 to the second flange 203 of the inlet part 201 of the pressure vessel in a fluid-tight manner. The coolant passage 305 is bounded between the electrode portion 301 of the pressure vessel and the cooling jacket 306 of the electrode portion. Coolant enters channel 305 through inlet 307 and exits through outlet 308.

As best seen in Figures 6B and 8, the copper collector electrodes 309a-309f are mounted on and extend through the flange 304 of the tubular electrode portion 301 of the pressure vessel. Although there are a total of six such electrodes 309, for clarity only one is illustrated in Figure 6B. Each copper collector electrode size 309 includes a phenolic flange 310 and a ceramic insulator 311. Each such electrode 309 is cooled by a fluid, preferably ethylene glycol, circulating in the inner channel 312, entering through inlet 313 and exiting through outlet 314. The electrical connection is denoted by reference numeral 315 · The polytetrafluoroethylene seal 316 helps to prevent leakage from inside the inert fluid collection chamber 406. Although, as shown in Fig. 16, the electrical system used in connection with the present reactor is of the 3-phase Y-coupling type, other systems may be used if conditions so require.

In particular, it can be seen from Figures 6B and 6C that each copper electrode 309 is attached by a tongue and groove connection to the first extreme end of the rigid carbon electrode extension 317. The extensions 317 of the electrode portion 412 protrude through the first portion 412 of the heat shield 410 but are not in contact therewith and are attached at their other extreme end to a curved heating element support 318. As best seen in Figure 10, the heating elements 302a-302c are attached from the first end together. curved heating element supports 318 and are circumferentially spaced around the reactor tube 401 within the inert fluid collection chamber 406. The heating elements are attached at one end to a 3-stage star point ring 319, as shown in Figures 6C and 10. Each electric resistance heating element 302 is preferably made of a fibrous refractory material such as graphite or carbon. The support elements 318 of the heating elements and the central clutch ring 319 may be made of an electrically conductive refractory material such as carbon.

C. Reactor main

It can be seen from Figures ββ, 6C and 9 that the tubular end portion 405 of the pressure vessel has first and second flange portions 414 and 415. The portion 405 is securely attached to the second flange 304 of the pressure vessel electrode portion 301 by its first flange 414. Flow duct 416 abuts the main vessel cooling flange 417. The channel 416 is further limited by a helical guide plate 418. The coolant enters the spiral duct 416 through inlet 419 and exits through outlet 420.

l

Reactor tube 401 includes three zones; pre-reaction zone 411, reaction zone 404 and post-reaction zone 422. As already mentioned above, the reactor tube 401 is made of a fibrous refractory material such as carbon or graphite fabric. The fabric may be knitted, woven or non-woven. The reaction tube 401 is attached at its outlet end 403 to the reactor tube outlet end support ring 424, which in turn is secured in place to the reactor tube attachment block 425. inside section 201. The inlet end of the bellows 427 is fluidly secured between the first flange 202 of the pressure vessel inlet portion 201 and the annular sealing flange 2U5 to ensure that the inlet end of the reactor tube 401 remains tightly separated from the manifold chamber 406. The bellows 427 may change

2 to 64056 The means for generating axial attraction in the reactor tube 401 include three identical portions spaced evenly around the circumferential surface of the pressure chamber inlet portion 201. For simplicity, section 428, illustrated in Figure 6A, will be explained below. Each member 428 includes a movable push rod 429, one end of which is attached to the reactor tube inlet support ring 426 and the opposite end of the annular plate 430. Each push rod 429 is supported by a bearing 431 which is fluidly sealed with an O-ring 432. is attached to an annular plate 430, anchors a rope 434 that runs generally parallel to the longitudinal axis of the reactor and over the rope pulley assembly 435. A weight 436 is attached to the opposite end of the rope 434 to cause a force to hold the reactor tube 401 under axial tensile stress.

In particular, it can be seen from Figures 6B and 6C that the heat shield 410 includes a first circumferential portion 438 located within the pressure vessel main assembly portion 405, radially outwardly between the heating elements 302a, 302b and 302c and the heat shield 410 between the first end portion 412 and the second end portion 439. As shown in Figure 6C, the first circumferential portion 438 of the heat shield 410 rests on a seat ring 437, which is preferably made of carbon. If desired, the first circumferential portion of the heat shield 410 may be extended toward the electrode portion 300 to include a second circumferential portion 440, as shown in Fig. 6B. Although molybdenum was the initial choice and has been found to be a satisfactory material for the type of heat shield required in the present high temperature chemical reactor, it is preferred that the heat shield 410 of the present embodiment be made of a graphite material such as pyrolytic graphite or Union Carbide Corporation and which is sold under the trade name "Grafoil".

Radiation meter openings 441 and 442 are located in the main body 400.

The opening 442 allows the reactor tube 401 to be monitored and the temperature of the reaction zone 404 to be measured, and the opening 441 allows the temperature of the heating elements 302c to be measured and monitored.

D. Post-reaction treatment equipment

As can be seen in Fig. 6C, the first flange portion 30 of the post-reaction treatment unit portion 501 of the pressure vessel? a fluid-retaining attachment to a fluid-cooled intermediate flange 25 6 4 0 5 6 503, which in turn is a fluid-retaining attachment to the second flange 415 of the main body of the vessel. The coolant passage 504 F is timed between the reaction of the post-reaction treatment section 501 and the pressure vessel. Coolant flows into channel 504 through inlet 506 and exits through outlet 507. The purpose of the radiation measuring port 509 is to enable monitoring and temperature measurement in the post-reaction zone 422 of the reactor tube 401.

The reaction products leaving the outlet end 403 of the reactor tube 401 of the embodiment of Figure 6 enter the first portion 510 of the hot tub 511. As shown in Figures 60 and 6D, the first portion 510 of the hot tub 511 includes an inner tubular wall 512 and an outer tubular wall 513 bounded by a cooling port. 514. The helical coolant guide plate 515 directs the coolant that enters through the inlet 516 and exits through the outlet 517. The first thermocouple probe 518, which extends into the first portion 510 of the hot tub 511, allows the temperature of the incoming reaction products to be measured. A second thermocouple probe 519 extending from the heat bath 511 to the first portion 510 measures the temperature of the reaction products at the outlet.

As seen in particular in Figure 6D, the first portion 510 of the hot tub 511 is connected to the second portion 520 by flanges 521 and 522. The second portion 520 includes an inner wall 524 and an outer wall 525 defining a coolant passage 526. Coolant enters the passage 526 through. Thermocouple probes 530 and 531 allow the temperature to be measured in the reaction products entering and leaving the second section 520.

In the embodiment shown in FIG. between the cooling jacket 505a and the post-reaction treatment apparatus section 501a of the pressure vessel. Coolant flows into channel 504a through inlet 506a and exits through outlet 507a. The radiation meter opening 509a allows inspection and temperature measurement in the post-reaction zone 422 of the reactor tube 401.

26 64056

The reaction products leaving the outlet end 403 of the reactor tube 401 of Figure 12 at high temperature go to a countercurrent heat exchanger 532 with a variable profile, the inlet end 533 of which is limited to the reactor outlet 403. The heat exchanger 532 comprises an inner tubular part 534 concentric with and spaced from the inner wall 534 and a helical baffle 536 located between the walls 534 and 535 defining a helical coolant passage 537. The inner tubular wall 534, the outer tubular wall 535 and the helical guide 536 together form a helical guide 536. a heat exchanger section 544 resting on a carbon felt mattress 545j located on the end plate 546 of the pressure vessel heat exchanger section 547. The coolant inlets 538, 539 and 540 extend through the outer tubular wall 535 and are in connection with helical refrigerant duct 537 *

In the embodiment shown in Figure 12, after the coolant has circulated through the helical coolant passage 537 in a preselected, variable and controllable manner, the coolant is removed from the outlet of the helical annular passage 537 near the inlet end 533 of the heat exchanger 532. The coolant then circulates through the inlet 542 in the reactor tube mounting block 425a to the inert fluid collection chamber 4θβ. In this case, it is obvious that the refrigerant used must be a fluid which is the same or at least compatible with the inert fluid present in the collector chamber 406. However, since the operation of the heat exchanger 532 does not require the refrigerant to be recirculated to the collector chamber 406, means are possible. In these cases, the choice of fluid coolant is not limited by the criteria set forth above. The cooling jacket 548 on the periphery of the heat exchanger is radially spaced outside the heat exchanger portion 547 of the pressure vessel, defining an annular passage 549 therein. identical to the inlet apparatus of Figures 6A and 6B except that the means of the inlet apparatus 200a for introducing the primary solid reactant 27 replaces the means of the inlet apparatus 200 for introducing the primary liquid reactant. For the sake of brevity, only those features of the embodiment of Figs. 13A and 13B that differ from the corresponding features in the embodiment of Figs. 6A and 6b will be described below.

The solid reactant inlet tube 232 extends through the annular nozzle block 204 and is fixedly attached thereto by a support flange 235. · The primary solid reactant, preferably finely divided, enters the inlet tube 232 through the inlet 233 in the support flange 235 and exits the reactor tube 401. Attached to the outlet 234 is a tubular shell 217 radially outwardly therein, the axis of which is substantially parallel to the axis of the reactor tube 401. Shell 217 helps to keep the finely divided solid reactants centrally within the pre-reaction zone 411 of the reactor tube 401.

Fig. 14 shows a solid reactant feed system 238 connected to a high temperature reactor having an inlet apparatus 200a of the type shown in Figs. 13A and 1.3B. The feed bunker 240 for the solid reactant feeds the grinder 241, which in turn feeds the screen 242. The coarse product outlet 245 from the screen 242 is recycled back to the grinder and the fine product outlet 243 is fed to a hopper 244 attached to an elongate tubular housing 246. A helical feeder 246 and is driven by a motor 248. The pressure-sealing fluid may be introduced into the housing 246 through an inlet nozzle 249 located at a point downstream of the hopper 244; the interior of the reactor tube 401 is thus tightly closed to the outside air. The solid reactant and sealing fluid are removed from the housing 246 to the reactor through the outlet 250.

F. Refractory Coating and Etching Systems For the reasons set forth below, it is contemplated that a refractory coating may be applied to the surfaces of reactor tube 401, heating elements 302, and heat shield 410 that are exposed to envelope gas and high temperatures during reactor operation. Such a refractory coating may be, for example, pyrolytic carbon or a refractory oxide such as thorium oxide, magnesium oxide, zinc oxide, alumina or zirconia. It is further contemplated that portions of the surface of the reactor tube 401 may optionally be etched or corroded.

28 6 4 0 5 6

Figure 15 is a schematic representation of a refractory coating and etching system including a first refractory deposition material measurement system 601 having a carbonaceous gas supply 602 connected to a carbonaceous gas measurement line 603. The measurement line 603 has an on / off valve 604 connected to a needle 60 606. The first supply line 608 connects the carbonaceous gas measurement line 603 to the mixed gas supply line 607.

The second refractory deposit measuring system 610 includes a transport gas supply 611 connected to a transport gas measurement line 612 having an on / off valve 613, a needle valve 614 and a flow meter 615 · The transport gas measurement line 612 is connected to a bubble tube 617 located in a tank 617 contains a solution of a volatile metal-containing compound. The temperature of the tank 617 is controlled by a temperature controller 618, which senses the temperature of the tank with a thermocouple 619 and, if necessary, supplies heat to the tank by an electrically heated jacket 620. The outlet end 621 of the bubble tube 6l6 The outlet 622 of the tank 617 connects the second supply line 623 to the tank at a point above the surface of the solution. The second supply line 623 is also connected to the mixed gas supply line 607.

In the etchant measuring system 625, the etchant supply line 626 is connected to the etchant measurement line 627, which in series includes an on / off valve 628, a needle valve 629 and a flow meter 630. A third supply line 631 is connected to the etchant measurement line 627.

All three lines 608, 623 and 631 supply a mixed gas supply line 607 branching at a T-connection 632. The first line 633 includes a first line valve 634 and is connected to a first inlet in an inert fluid mixing manifold 635. The second line 636 includes a second line 637 connected to the first inlet in the sweep gas mixing manifold in line 638.

The inert fluid supply 640 is connected to an inert fluid measurement line 641, which includes an on / off valve 642, a needle valve 643, and a flow meter 644 connected to a second inlet in the inert fluid mixing manifold 635. The mixing line 29 6 4 0 5 6 The outlet 635 is connected to an inert fluid supply line 645, which in turn is connected to pressure vessel inlets 4o8 and 409 for directing inert fluid to an inert fluid collection chamber 406. A collector chamber pressure sensor 646 is connected to the inert gas supply line 645 to measure in the chamber. The collector chamber outlet valve 647 is also connected to the inert fluid supply line 645 and forms an outlet for discharging fluid from the collector chamber.

The sweep gas supply 648 is connected to a measurement line 649 including an on / off supply valve 650, a needle valve 651 and a flow meter 652 connected to a second inlet in the sweep gas mixer manifold line 638. The output of the mixer line 638 is connected to to introduce a sweep gas inside the reaction tube 401. The pressure sensor 654 of the reaction zone, which connects to the scrub gas supply line 653 and communicates with the interior of the reactor tube 401, measures the pressure in the reaction zone of the reactor.

As shown in Figure 6D, the shut-off valve 655 at the outlet of the reactor tube is attached to the second portion 520 of the hot tub 511 by flanges 555 and 656.

When the reactor is operating, a pressure difference must be maintained between the inert fluid in the collector chamber 406 and the gas in the reactor tube 401 to provide a uniform flow of inert fluid radially inward through the porous wall of the tube 401. Thus, it is preferred that the tissue tube 401 be sufficiently rigid so that the pressure difference can be maintained without the tube 401 collapsing inward. Accordingly, it is designed that a refractory coating of, for example, pyrolytic carbon is deposited on a portion of the refractory material of the reactor tube 401 located within the cavity of the black body to increase tissue stiffness or dimensional stability.

To provide such a coating, the shut-off valve 655 at the outlet of the reactor tube is closed and the reactor tube is heated to a temperature of about 1900 ° C. Thereafter, the on / off valve 650 in the sweep gas measurement line 649 is opened, the on / off valve 642 in the inert fluid measurement line 641 is closed, and the collector chamber outlet valve 647 is opened, allowing the sweep gas to flow out of the reactor tube 401. through the wall to the collector chamber 406 and finally through the pressure vessel inlets 408 and 409 and the collector chamber outlet valve 647. The on / off valve 604 is then opened in the carbonaceous gas measurement line 603. registered to the flow meters (dispensers) 606 and 652. The valve 634 of the first line branch is closed and the valve 637 of the second branch line is opened so that carbonaceous gas flows through the first supply line 608, the mixed gas supply line 607, the T-connection 632, the second line branch 636 and the to a collector line 638, where it mixes with the sweep gas and flows inside the reactor tube 401 through the sweep gas supply line 653 and the purge gas inlet connector 225.

The carbonaceous gas dissociates on the heated surfaces it contacts, depositing a pyrolytic graphite drop coating on these surfaces. Thus, the pyrolytic graphite is generally deposited on those parts of the reactor tube 401, the heating elements 302 and the heat shield 410 which are inside the cavity of the black body.

Since the part of the reactor tube 401 in the pre-reaction zone 411 is outside the black body cavity and thus cannot be comfortably heated to temperatures above the decomposition temperature of the carbonaceous gas, it is designed that the stainless steel mesh 450 shown in Figures 6a and 6B is placed to prevent the flexible reactor tube 401 from collapsing inwardly due to the pressure difference of the inert fluid, although it has been found that increased tension in the porous tissue produces substantially the same result.

To control the flow rate of the inert fluid through the walls of the reactor tube 401, the pores of the tube wall can be reduced or enlarged while the reactor is operating by mixing the refractory deposit or etchant with the inert fluid. The pressure difference between the collector chamber and the reaction zone can be monitored by pressure sensors 646 and 654, and the flow rate of inert fluid through the wall can be monitored by a flow meter 644.

31 64056

When the pressure difference becomes too low for the desired inert envelope gas flow rate, the pore diameter of the reactor tube wall can be reduced by opening the on / off valve 604 and positioning the needle valve 605 to allow carbonaceous gas from the carbonaceous gas supply 602 to flow through the carbonaceous gas measurement line 603. The second line branch valve 637 is closed and the first line branch valve 634 is opened to direct carbonaceous gas to the inert fluid mixing manifold 635 and from there to the manifold 406 through the inert running gas supply line 645 and the pressure vessel inlet outlet. during. The carbonaceous gas dissociates on the heated surfaces in the reactor it contacts. Accordingly, the carbonaceous gas flowing into the pores of the wall tissue of the reactor tube 401 dissociates by depositing a pyrolytic graphite coating which reduces the pore diameter. As the pressure difference across the reactor tube wall increases with a fixed flow of inert fluid, the decrease in tube porosity can be monitored by pressure sensors 654 and 646 and a flow meter 644 as graphite deposits. When the pressure difference exceeds a predetermined value, the growth of the graphite coating can be stopped by closing the on / off valve 604 in the carbonaceous gas measuring line 603. The whole process of reducing the pores in the reactor tube wall can be carried out without interrupting the reactor operation.

Conversely, it may be necessary to increase the pore diameter in the reactor tube 401. In this case, a corrosive such as steam or molecular oxygen from the corrosive reservoir 626 is mixed with the inert fluid by opening the valve 628, 637 and opening the valve of the first line 634. The corrosive material mixes with the inert fluid in the inert fluid mixing manifold 635 and flows into the collection chamber 406 through the inlet 408 and 409 of the pressure vessel. diameter. The flow of the corrosive may be continued until the pressure sensors 654 and 646 show a sufficiently low pressure difference across the wall of the reactor tube 401 for the desired inert fluid flow rate monitored by the flow meter 644. As with pore size reduction,

In some applications, it may be advantageous to use as an inert fluid a vapor or other substance that reacts with the chemically treated substances. In order to prevent or at least slow down the corrosion of the materials from which the reactor is built, it is designed that a coating of refractory oxide such as thorium oxide, magnesium oxide, zinc oxide, alumina or zirconia is applied to the reactor tube 401, heating elements 302 and heat shield 4 in fluid and operate at high temperatures. A refractory coating agent which is a volatile metal-containing compound such as methylmagnesium chloride, magnesium ethoxide or zirconium n-amyloxide can be used to deposit the refractory oxide coating. For example, methylmagnesium chloride decomposes on a surface heated to about 590 ° C, depositing a magnesium metal coating. The hot magnesium metal is then oxidized by introducing steam or molecular oxygen into the collector chamber 406. Zirconium n-amyloxide and magnesium ethoxide both generally decompose on heated surfaces to form zirconia and magnesium oxide, respectively.

In the case shown in Figure 15, the volatile metal-containing compound can be introduced into the collecting chamber 406 by causing the transport gas from the supply reservoir 611 to flow through the measuring line 612 dissolved in diethyl ether or zirconium n-amyloxide dissolved in tetrahydrofuran. The transport gas flows through the bubble tube 616 and into the solution in the tank 617. The valve 637 of the second line remains closed and the valve 634 of the first line remains open for the purpose of sequentially directing the carrier gas, solvent vapor and metal-containing compound vapor through the outlet 622 of the tank 617 to the first line 623 of the second feed line 623. to the collector line 635 »where they mix with the inert fluid and then pass to the collector chamber 406 through the inert fluid supply line 645 and the pressure vessel inlet 408 and 409 · The volatile metal-containing compound decomposes inside the reactor on the hot surfaces it contacts. If it decomposes into pure metal, oxygen or water vapor is then introduced into the collection chamber 406 to cause oxide formation.

G. Process Variable Control System

Figure 16 illustrates a reactor temperature control system 700. The figure shows heating elements 302a, 302b and 302c schematically connected to a star-shaped circuit, one end of each heating element being connected to a star point 701 and the other end connected to one conductor 702a, 702b or 702 of a three-phase power line 702. The star point 701 corresponds to the three-phase connection ring 319 in Fig. 6C. The radiation meter 708, located in the viewing aperture 441 of Figure 6B, is focused on the heating element 302c and produces a signal, generally in the millivolt range, corresponding to the temperature of the heating element. The MV / I converter 709 amplifies the radiation signal and converts it into an electric current. The setpoint controller 707, the output signal line 712 for connection to a computer or calculator, and the recording device 710, which makes a permanent log of the temperature measured by the radiation meter 708, are all connected to the converter 709. The input signal line 713 connects the setpoint controller 707 to a control signal input (not shown). Current meters 750a, 750b and 750c are disposed in three branches 702a, 702b and 702c to measure the current supplied to the heating elements 302a-c; and voltmeters 751a, 751b and 751c are connected to branches 702a-c to measure voltages acting on the heating elements. The power consumed by the heating elements and their electrical resistance can be calculated from these current and voltage measurements. Information about the electrical resistance of a heating element provides information about its physical integrity, because as the heating element corrodes, its electrical resistance increases.

Figure 17 is a graphical representation of a graphite fabric sample sold under the tradename "WCA Graphite Cloth", sold by Union Carbide Corporation, from an electronic plate resistor as a function of fabric temperature. The fabric is stiffened with pyrolytic graphite by heating and exposing it to a carbonaceous atmosphere substantially as described above. The vertical axis ^ 64056 of the graph of Fig. 17 gives the plate resistance in "ohms / square" units, because it is known that the resistance measured between opposite edges of a square of a given thickness of resistance is independent of the dimensions of the square. Thus, the resistance of a heating element formed of a single rectangular strip of "WCA Graphite Cloth" at a given temperature can be obtained by thinking of the strip made of fabric squares connected in series. For example, the resistance of a strip of 15.3 cm by 128 cm, measured at 1500 K between two 15 cm edges, is obtained by multiplying (128 / 15.3) times 0.135 ohms, the plate resistance at 1500 K given in Fig. 17. is made of more than one layer of fabric, each layer having the same dimensions and therefore the same resistance, the total resistance is obtained by dividing the resistance of one layer by the number of layers. For convenience, the plate resistances in "ohms / square" units have also been calculated for the graphical representation of Figure 17 for samples of stiffened "WCA Graphite Cloth" made of 2, 3 and 4 layers.

In operation, after the setpoint controller 707 is set to a certain temperature either manually or by computer, it compares this temperature with the measured temperature of the electrode 302c and produces a difference signal (error signal) depending on the algebraic difference between the measured temperature and the set temperature. The setpoint controller 707 controls the trigger circuit 706, which, depending on the difference signal, causes the power controller 704 to increase or decrease the power supplied to the heating elements to reduce the magnitude of the difference signal as needed, bringing the temperature of the heating element 302c closer to the set temperature. Because the heating element 302c is within the cavity of the black body surrounded by the heat shield 410, its temperature generally represents the temperature of the surfaces throughout the cavity. However, radiation meters focused on other surfaces within the black body can also be used to control the temperature.

As shown in Figure 18, in addition to temperature, process variables can be controlled by feedback control systems, such as a liquid main reactant feed rate control system 714, which includes a feed storage 715> communicating with the measurement system 716 via a feed line 717. The metering system 716 controls the flow rate of the main reactant and may include, for example, a variable speed pump and pump controller or a variable orifice valve and valve controller. The output 718 of the main reactant measuring system 716 is connected to a flow rate transducer 719 which produces an electrical signal output 720 corresponding to the flow rate of the main reactant. The output 721 of the main reactant flow rate transducer 719 is connected to the liquid main reactant input line 215. The signal output 722 from the reaction zone pressure sensor 654 and the signal output 720 from the flow rate transducer 719 are connected to the second signal of the main reactant measurement system 716, respectively. The output of the computer system 723 is connected to the third input of the measuring system 716.

In one mode of operation of the liquid main reactant feed rate control system 714, the computer system 723 provides both a preset value for the main reactant flow rate and an upper limit of the reaction zone pressure for the main reactant measurement system 716 . If the pressure in the reaction zone exceeds this upper limit, the measuring system 716 reduces the pressure by reducing the flow rate of the main reactant.

The liquid secondary reactant flow rate control system 724 is a second feedback control system that includes a supply reservoir 725 connected to the measurement system 726 via the supply line 727. The secondary reactant measurement system 726 may be of the same type as the main reactant measurement system 716. which produces a signal corresponding to the flow rate of the secondary reactant. The output 731 of the transducer 729 is connected to the secondary reactant input 221. The signal output 722 from the reaction zone pressure sensor 654 and the signal output 730 from the secondary reactant flow rate reducer 729 are connected to separate signal inputs. The liquid secondary reactant flow rate control system 724 can be used in the same manner as described above in connection with the liquid main reactant control system 714.

In the inert fluid flow rate control system 73, the inert fluid supply 640 is connected to a needle valve 643, 36 64056 which in turn is connected to an on / off valve 642. Valve 642 is connected to an inert fluid flow rate transducer 735 · Transducer 735 in substance needle valve controller 737-The second inlet of needle valve controller 737 is connected to computer system 723 and the third inlet is connected to collector chamber pressure sensor 646. Inert fluid outlet from transducer 735 is connected to reactor pressure vessel inlets 648 and 409 · For convenience the meter 644 and the inert fluid mixing manifold of Fig. 16 are not shown in Fig. 18 and the inert fluid flow rate transducer 735 of Fig. 18 is not shown in Fig. 15 ·

In operation, an on / off valve 642 is opened, which allows inert fluid to flow through the transducer 735 and into the inlets 408 and 409. · The needle valve controller 737 compares the flow rate signal the pressure does not exceed the upper limit also determined by the computer system 723 ·

If the pressure is too high, the needle valve guide 737 lowers the flow rate to reduce the pressure.

Reactor temperature control system 700, detailed in Figure 16 and shown schematically in Figure 18, includes a reactor temperature controller 738 including a power controller 704, a trigger circuit 706, a setpoint controller 707, a converter 709, a register 710, and meters 750 and 751, shown in Fig. 17 · A radiation meter 708 (not shown in Fig. 18) is located in the viewing aperture 441 and connected to the controller 738. A three-phase power line 702 connects the heating power output 703 of the reactor temperature controller 738 to the heating elements 302 (not shown in Fig. 18) via electrodes 309. Thus, the level of electrical power supplied from the heating power output 703 determines the temperature of the reactor tube 401. The control signal input 711 and one output from the reactor temperature controller 738 are connected to the computer system 723 by an input signal line 713 and an output signal line 712, respectively.

The reactor product sampler 740, connected to the outlet 741 located near the reactor outlet shutoff valve 655, transfers samples from the reaction product to the sample inlet 742 of the gas chromatograph 743 at pre-selected intervals. For example, a gas chromatograph! 743 together with the reaction product sampler 740 can produce a signal corresponding to the ethylene concentration in the process of partial hydrocarbon pyrolysis.

The outputs of the gas chromatograph 743 are connected to a recorder 749 and a computer system 723. to the gas chromatograph 743 · Other transducers may be connected to the data bus 746 if desired. The output 747 of the computer system 723 is connected to a command bus 748 containing signal lines · Computer system 723 may include a digital computer, an analog-to-digital converter for converting analog signals from a transducer to digital data for a calculator, a digital-to-analog converter for converting digital signals for a calculator to analog as a control signals and a multiplexer for connecting the signal lines of the data bus 746 and the command bus 748.

We have designed that during the process, the computer system 723 can determine and monitor process variables with signals transmitted through the instruction bus 748 and the data bus 746. Thus, computer system 723 can monitor reactor operation to ensure that process variables remain within specified limits. In addition, the computer may be programmed to obtain optimal operating conditions for a particular process by making systematic changes in process variables while monitoring reactor outlet chromatography. 743 · For example, the computer may be programmed to retrieve reactor temperatures and feedstock flow rates to maximize ethylene concentration at hydrocarbon feed. Computer system 723 may also be included in feedback control systems; such as a reaction product monitoring system that includes, in addition to the computer system, a reaction product sampler 740, a gas chromatograph 743, a reactor temperature controller 738, and a three-phase power line 702 connected to the heating elements 302.

38 64056 In this reaction product monitoring system, a computer system compares the chemical composition of the reaction product samples taken from the reactor with a preselected composition and produces at its output 7 ^ 7 an electrical signal corresponding to deviations in the chemical composition of the samples. The output 7 ^ 7 of the computer system 723 is connected to the reactor temperature controller inlet 711 for the purpose of allowing changes in the reactor tube temperature as a function of changes in the computer system signal, thus reducing deviations in the chemical composition of the reaction products. Other process variables, such as feed rates and pressures of selected reactants in the reaction zone, can also be monitored by similar feedback monitoring systems.

process parameters

In high temperature chemical reaction processes conducted in accordance with the present invention, it is necessary to use an annular shell or curtain of an inert fluid that is substantially permeable to radiation. The curtain has a substantial axial length. The annular curtain may be generated in a direction generally parallel to its axis, or in a direction generally perpendicular to its axis and radially inwardly from its outer circumferential surface.

The integrity of the fluid curtain is independent of flow restrictions and can be maintained axially for much longer than is achievable in the case of an axially sprayed laminar curtain. The primary requirement is to maintain the inert fluid flow at a higher pressure than the reactant flow to prevent the reactants from puncturing the 39 6405 6 envelope or otherwise breaking out of the space enclosed by the envelope.

After the curtain is generated, at least one reactant is passed through its core along a predetermined path that substantially coincides with the axis of the curtain.

The curtain confines the reactants within and keeps them from contact with the surfaces bounding the reaction chamber.

Finally, very strong radiant energy is directed to the core of the curtain to coincide with at least a portion of the predetermined path of the reactants. This radiant energy can be directed along a finite length of path. Sufficient radiant energy will be absorbed into the core to raise the temperature of the reactants to the level required to initiate the desired chemical reaction.

In the event that the reactants themselves do not absorb the radiant energy, the absorbent target can be introduced along the path of the reactants, preferably before the radiant energy is directed to the core. The target substance then absorbs sufficient radiant energy to raise the heart temperature to the level required to initiate the desired chemical reaction. As already mentioned above, if the planned reaction is such that the permeable reactants produce at least one product that absorbs radiant energy, the feed of the target substance can be stopped after the reaction is started.

The planned process may further include the step of cooling the reaction products and any remaining reactants and / or target substances immediately after the desired reaction has been completed. The purpose of this procedure is to terminate the desired reaction and prevent the occurrence of other undesired reactions. Products, target substances, and residual reactants can be conveniently and efficiently cooled by radiation-based heat transfer to a cool, radiation-energy-absorbing surface.

6 4 0 5 6

Use of liquid or gas wall reactors

The liquid or gas wall reactors according to the invention can in principle be used in any high-temperature chemical reaction, many of which have previously been considered either impossible or only theoretically possible. The most important criterion for the use of these liquid or gas walled reactors in a particular high temperature chemical reaction is whether such a reaction is thermodynamically possible under the reaction conditions. Using these liquid or gas walled reactors, such high temperature chemical reaction processes can be carried out at temperatures up to 330 ° C (1) by creating an annular curtain or shell inside the porous reactor tube consisting of an inert fluid substantially radially flowing. energy and forms a protective curtain on the radial inner surface of the reactor tube and the curtain has a substantial axial length and the interior of the curtain forms a reaction chamber; (2) passing at least one reactant (which may be in a solid, liquid, or gaseous state) through the reaction chamber along a predetermined path substantially coinciding with the longitudinal axis of the curtain, the reactants being within the reaction chamber; and (3) directing high power radiant energy into the reaction chamber to coincide with at least a portion of the predetermined path of the reactants, wherein sufficient radiant energy is absorbed into the reaction chamber to raise the temperature of the reactants to the level required to initiate the desired chemical reaction.

Among the reactions that can be carried out with the liquid or gas wall reactors of this invention are the dissociation of various fractions of hydrocarbons and hydrocarbonaceous substances such as coal and petroleum into hydrogen and carbon black; steam-reforming of coal, petroleum fractions, shale oil, tar sludges and other carbonaceous or hydrocarbonaceous feedstocks into synthesis-gas mixtures, which processes may include one or more inorganic carbonates (such as limestone or dolomite) or an inorganic oxide or an inorganic oxide that these can be removed from the resulting synthesis gas mixtures; partial dissociation of hydrocarbons and hydrocarbonaceous substances into lower molecular weight compounds; partial pyrolysis of saturated hydrocarbons to unsaturated hydrocarbons such as ethylene, propylene and acetylene; conversion of organic waste materials such as sewage sludge or lignin-containing by-products into fuel gas; complete or partial desulphurisation of sulfur-containing hydrocarbon feedstocks; reduction of mineral ores or inorganic compounds to a lower valence state by hydrogen, carbon, synthesis gas or other reducing agent; • and partial or complete reaction of an inorganic element or compound with a carbonaceous substance to form the corresponding inorganic carbide.

If desired, one or more catalysts may be used in such high temperature chemical reaction processes to accelerate the reaction or to change its course to the desired reaction order. When such processes comprise carbonaceous or hydrocarbonaceous reactants, the addition of a suitable catalyst to the system can be used to promote the formation of free radicals, carbonium ions or carbanions to affect the course of the reaction.

Of course, no set of operating conditions is optimal or suitable for all reactions that can be performed in a liquid or gas-walled reactor. Operating conditions such as temperatures, pressures, feed rates, residence time in the reactor tube, and cooling rates can be varied to suit the particular reaction being carried out. To illustrate, the factors that affect hydrocarbon pyrolysis products include the temperature at which the hydrocarbon is heated and the length of time the hydrocarbon is heated and the length of time it is maintained at that temperature. For example, it is known that methane must be heated to about 1230 ° C to produce acetylene. Ethylene formation from ethane begins at a lower temperature, about 830 ° C. In a typical process for the pyrolysis of hydrocarbons, acetylene, ethylene, hydrogen, carbon black and hydrocarbon oils are produced. Reaction times on the order of milliseconds generally maximize acetylene uptake, as reaction times greater than milliseconds generally favor the production of ethylene and other products at the expense of acetylene, while reaction times less than milliseconds generally reduce both ethylene and acetylene uptake. Very high temperatures, for example above 1650 ° C, generally favor the production of carbon black and hydrogen at the expense of acetylene and ethylene.

1) 2 64056

The reaction times in the liquid or gas-walled reactors of the present invention can be shortened by shortening the reactor tube and increasing the flow rate of the reactants introduced into the reactor tube. For very short reaction times, it may be advantageous to mix a radiation-absorbing target with the reactants in order to promote efficient coupling between the reactant flow and the thermal radiation of the tube wall and thus help to heat the reactants rapidly.

eXAMPLES

The following examples illustrate the ease with which various high temperature chemical reaction processes can be carried out in liquid or gas walled reactors in accordance with the present invention. In each of these examples, the high temperature, liquid or gas wall reactor shown in Figures 1A-5 was used to carry out a particular high temperature reaction. Reactor tube 61 was a porous graphite tube having a length of 90 cm, an inner diameter of 7.5 cm, and an outer diameter of 10 cm, with an average pore diameter of 20 microns. The porous tube was enclosed in a steel pressure vessel 70 with a diameter of 25 cm. The reactor tube 6l was heated by carbon electrodes 100a-100f placed in the collector chamber 85. The heat shield 120, which was also located in the collector chamber 85, was made of molybdenum. A water-cooled collar 125 was placed near the outlet end of the reactor tube 6l to cool the reaction products formed by the radiation coupling. After each experiment was run for different lengths of time, reactor tube 61 was inspected for the accumulation of carbon black and other substances. Nothing was observed.

Example 1

Thermal dissociation of methane

A series of experiments were performed to determine the efficiency of a liquid or gas walled reactor in the thermal dissociation of natural gas at different feed rates and reaction temperatures. In each of these experiments, hydrogen was introduced into the collector chamber 85 through inlet 83 and forced through the porous reactor tube 61 into the reactor chamber at a constant rate of 140 rpm. The current through the carbon electrodes 100a-100f was adjusted to bring the temperature of the reactor tube between 1260 and 1870 ° C as measured by an optical pyrometer. Natural gas containing more than 95% methane and the remainder ethane and propane was introduced into the reactor via inlet 91 at various flow rates ranging from 28-140 rpm. A small amount of carbon black was introduced into the reactor simultaneously via inlet 121 to act as an absorbent target to initiate pyrolytic dissociation. After dissociation had begun, it was no longer necessary to add carbon black to maintain the reaction. Dense black smoke flowed from the outlet end of the reactor tube and was found to consist of carbon black and hydrogen. The carbon black particles were extremely fine and difficult to filter. By spraying water into the effluent just below the outlet end of the reactor tube 6l, it was possible to incense the carbon black particles and collect them on a fabric dust filter. Table I gives the percentage dissociation at different flow rates from 28 to 140 1 / min. and at dissociation temperatures of 1260-18870 ° C, the proportion of dissociated methane was determined by measuring the thermal conductivity of the exhaust gas after the carbon black particles were filtered from the sample.

Table I

Percent dissociation at different flow rates and temperatures

Dissociation- Flow rate temperature ° C 1 / min.

28 56 84 112 140 1260 86 74 66 60 54 1370 89 79 72 68 63 1480 91.5 83 78 74.5 70.5 1590 94 88 84.5 82.0 79 1650 95.5 91 88.5 86 83 5 1700 97 94 92.5 91.0 89.5 1760 98.5 98.5 98.5 98.5 98.5 1815 100 100 100 100 100 1870 100 100 100 100 100

Example II

Thermal dissociation of liquid hydrocarbons

A series of experiments were performed with the intention of determining the efficiency of a gas wall reactor in the dissociation of liquid hydrocarbons. Hydrogen was used as the jacket gas at a constant flow rate of 14 ° 1 / min. The liquid hydrocarbons selected for the test series were typical distillates obtained from petroleum and included naphtha (boiling point 37-93 ° C); kerosene diesel (boiling point 104-177 ° C); gas oil (boiling point 177-315 ° C); and residual oil and asphalt (boiling point above 315 ° C). The results of these experiments were as follows: ^ 64056 A. Naphtha. The oil stream at a temperature of approximately 27 ° C was fed to the reactor tube 6l through inlet 121 at a rate of 0.19 liters per minute. The reactor tube temperature was maintained at 1870 ° C. Pure naphtha passed through the reactor unaffected, apparently permeable to the thermal radiation emitted from the glowing reactor tube. The naphtha was then made opaque by mixing with 0.1% by weight of fine carbon black. When this opaque mixture was introduced into the reactor as above, there was excellent coupling to thermal radiation. Carbon black and hydrogen flowed from the reactor tube outlet. Analysis of the product gas by the thermal conductivity cell turned out to be greater than 98 mole percent hydrogen, indicating that the dissociation was almost complete.

B. Kerosene diesel. Kerosene diesel was mixed with 0.1% by weight of carbon black and then fed to a gas wall reactor at a rate of 0.19 liters per minute. The reactor tube was maintained at 1870 ° C. Kerosene diesel dissociated into carbon black and hydrogen. Thermal conductivity measurements showed that the exhaust gas comprised more than 98 mole- $ of hydrogen.

C. Gas oil. Gas oil mixed with carbon black was introduced into a gas wall reactor at a flow rate of 0.19 liters per minute.

When the reactor tube was maintained at 1870 ° C, the gas oil dissociated into carbon black and hydrogen, which, separated from the carbon black, was found to form 98 mole percent pure hydrogen based on thermal conductivity measurements. When the reactor tube temperature was lowered to 1537 ° C, the exhaust gas from the reactor changed from a dense black smoke to a light gray mist, indicating that at the lower reaction temperature, the gas oil dissociated only partially, probably into lighter hydrocarbon fractions and a small amount of carbon.

D. Residual oil and asphalt. The residual oil containing asphalt was introduced into a gas wall reactor at a rate of 0.19 liters per minute and completely dissociated into carbon black and hydrogen when the reactor tube was maintained at 1870 ° C. Thermal conductivity analysis of the gas component of the exhaust gas showed that it was more than 98 mole percent hydrogen.

45 64056

Example III

Coal Thermal Dissociation A sample of Utah soft coal was analyzed and found to contain 0.58 wt. sulfur and 8.55 weight? ash. The carbon was ground at -50 mesh and fed to the reactor at a rate of about 16 kg per hour. The reactor tube 6l was kept at 1650 ° C and protected by a nitrogen curtain forced through a porous wall at a rate of 140 l / min. Carbon dissociated. carbon black, gaseous products and light coke.

The carbon black differed from the carbon black produced in Example I in that the particles were large enough to be filtered without the addition of water. Carbon black was found to contain 8.63 wt. ash and 0.54 weight? sulfur. The gaseous product was a mixture of hydrogen and nitrogen (the latter from a gas curtain) containing only 0.02 molar? sulfur present as hydrogen sulfide.

About 62 weight? the starting material became converted to coke. This coke was very light and transparent; its density was only 35? the density of the carbon from which it was made. Freshly prepared coke spontaneously oxidized to ash in air in less than 12 hours, indicating that it had a high surface activity. When coke was allowed to remain at room temperature under a nitrogen atmosphere overnight, it showed no surface activity and did not spontaneously oxidize when subsequently exposed to air. Microscopic examination of the coke showed that it contained small, hollow, spherical granules of glass-like material. Chemical analysis showed that the coke contained 8.27 wt. ash and 0.70 weight? sulfur.

Example IV

Coal Steam Reforming and Gasification A sample of coal from Carbon County, Utah containing ash limestone was analyzed and found to contain 0.60 wt.%. sulfur. The carbon was ground to -50 mesh and fed to the reactor at a rate of about 4.74 kg per hour. Steam at 120 ° C was simultaneously introduced into the reactor at a rate of 9 kg per hour. The reactor tube 6l was kept at 1870 ° C and protected by a hydrogen curtain forced through a porous wall at a rate of 140 l / min. Dense white vapor was found to leave the reactor outlet. There was no indication that carbon black or heavy residue had been produced. No ash or other solids were found in the funnel located directly below the outlet of the reactor tube, indicating that any solid residue of carbon was contained in the gaseous product.

The solids were filtered from the exhaust gas and the residual gas was dried on a mass spectrometer before analysis. The results of the analysis, excluding air, are as follows (concentrations are given in molar percentages): nitrogen 0.051%>, carbon monoxide 7.563% ·, no hydrogen sulphide was detected; no carbon disulfide was detected; carbon dioxide 0.277% hydrogen 89.320%; methane 1.538%; other hydrocarbons such as benzene, acetylene, etc. 1.253% · The gaseous product obtained from this process is suitable as a fuel. In addition, no sulfur-containing components were detected in the analysis, although the mass spectrometer was able to detect sulfur compounds at concentrations as low as 10 parts per million. This indicated that substantially all of the sulfur originally present in the carbon was contained in the solid particles that were filtered from the exhaust gas stream.

Example V

oil shale steam reforming and gasification A sample of Green River oil shale obtained from a source in Rifle, Colorado, was ground to a size of -100 mesh. The sample was analyzed to determine the different carbonaceous substances in the oil shale. Methylene chloride at room temperature extracted 0.93% by weight of the slurry. The sample was further analyzed by heating part of it in air and observing weight loss as a function of temperature. The results of this additional analysis were as follows: Temperature range Weight loss% Remarks 20-500 ° C 11.60 Volatile distillation 500-780 ° C 2.50 Oxidation of carbon 780-1200 ° C 12.00 Decarboxylation of CaCO 2 R From these measurements it was estimated that oil shale consisted of 15% by weight of organic matter and 26.3% by weight of limestone CaCO 3. The remaining 57.5% by weight was assumed to be a quartz-containing substance.

„64056

The ground sample was introduced into the reactor at a rate of 17.25 kg per hour. At the same time, steam was fed to the reactor at a rate of about 9 kg per hour. The steam temperature was 120 ° C at the reactor inlet. The reactor tube was maintained at 1700 ° C and hydrogen, which was sprayed through the porous wall at a rate of 140 Ι / min, served as the envelope gas. Colorless steam flowed from the pipe outlet. The temperature of this steam was measured to be 520 ° C just below the reactor outlet.

Solid ash material was also produced and fell into the funnel below the reactor tube. The ash consisted predominantly of molten glass beads of different colors. This material was analyzed for carbonaceous residue by grinding and performing the same heating / weight loss analyzes as on the original oil shale. No weight loss was observed when heated from 500 ° C to 780 ° C, indicating that no organic matter was present in the ash material in the original slate. A 14% weight loss was observed when the solid ash was heated from 70 ° C to 1200 ° C, indicating that most of the calcium carbonate in the original sample remained in the ash and that some of this calcium carbonate had become decarboxylated during the reaction. Treatment of the ash with 0.1 N HCl resulted in the evolution of hydrogen sulfide and carbon dioxide, indicating that the sulfur that had been present in the original sample was at least partially also found in the ash.

The gaseous component of the reaction off-gas was dried and then analyzed by mass spectrometry. The results, expressed as mol%, are as follows: hydrogen 87.86% methane 0.74% acetylene 0.07% ethylene 0.39% nitrogen 1.24 carbon monoxide 8.70 l; miscellaneous hydrocarbons 0.04% carbon dioxide 0.016% \ benzene 0.016% \ toluene 0.002% \ and hydrogen sulfide less than 0.005% · This gas is suitable for use as a low-sulfur fuel.

Example VI

Steam reforming and gasification of sewage sludge A sample of activated sewage sludge comprising dried human waste mixed with a quartz-containing clay binder and formed to a particle size of approximately 2 mm was analyzed and found to have the following composition (concentrations expressed as 4% v / v 33.2% \ organic nitrogen 48 640 5 6 6.04% \ organic sulfur 0.23 water 6.14% and inorganic residue 50%.

The slurry was fed to the reactor at a rate of 24.4 kg per hour. A total of 11.3 kg was added. Steam at 120 ° C was simultaneously fed to the reactor at a rate of 24.87 kg per hour, which was about twice the stoichiometric rate for the water-gas reaction. Hydrogen was sprayed through the porous wall at a rate of 140 Ι / min. The reactor temperature was maintained at 2070 ° C.

The reaction products were a dense white mist and a solid residue. The residue collected in the well below the reactor tube weighed 6.8 kg and corresponded to 60% of the weight of the activated slurry. The residue had the following composition (concentrations are expressed as weight percent): organic carbon 12.88%; organic hydrogen 1.69 organic nitrogen 2.34% \ organic sulfur 0.37% \ water (small amount); and 83% of inorganic residue ·

Part of the reactor effluent was condensed in a liquid nitrogen trap. The trapped sample was brought to room temperature and found to have liquid and gaseous components. The liquid had a boiling point of 100 ° C, indicating that it was water. The gaseous component suitable for use as a low sulfur fuel was analyzed by mass spectrometry and gas chromatography and found to have the following composition (concentrations are expressed in mole percent): hydrogen 60.93% ammonia 0.0005% methane 1.320%; water 0.083% \ acetylene 0.463 ethylene 0.304% \ ethane 0.102 hydrogen cyanide 0.28%% nitrogen 0.990 carbon monoxide 34.122%; oxygen 0.0005 butene 0.173% ', butane 0.026%; carbon dioxide 0.996% \ benzene 0.100% \ toluene 0.019%; hydrogen sulfide 0.0005%; and dicyanate 0.008%.

Example VII

Partial pyrolysis of gas oil

In order to introduce the use of a liquid or gas wall reactor in the partial pyrolysis of petroleum distillates, light lubricating oil (Lube stock) or "gas oil" was partially pyrolyzed. This petroleum distillate was characterized by the following distillation analysis: 49 64056 Temperature ° C Distilled%

79 O

200 10 220 20 230 30 250 ^ 0 270 50 278 60 278 70 280 80 280 90

The gas oil was introduced into the reactor tube in the form of a mist by spraying it through a spray nozzle. Hydrogen was used as a spray gas and to form a gas wall. In addition, hydrogen was introduced at the inlet end of the reactor tube through the scrub gas inlet to sweep the gas oil mist through the tube.

The reactor tube was initially heated to 1870 ° C, at which time hydrogen was introduced into the collector chamber at 140 rpm. to form a gas wall and hydrogen at a rate of about 140 1 / min. was taken to the sweep-gas inlet. Gas oil was then introduced into the reactor tube at a rate of about 0.95 liters per minute using about 140 l / min. hydrogen as a spray gas. The exhaust gas flow temperature just below the outlet of the reactor tube was set at about 438 ° C by lowering the temperature of the reactor tube to 1425 ° C. Prior to sampling, the reactor was allowed time to equilibrate under these operating conditions.

Samples of the effluent were collected by three methods, namely (1) passing a portion of the effluent through a liquid nitrogen trap and collecting the sample by cooling it; (2) collecting gaseous samples from the flow at a point downstream of the liquid nitrogen trap; and (3) passing a portion of the flow through a water-cooled condenser and collecting the liquid fraction. The material collected with a liquid nitrogen trap was allowed to warm to about 10 ° C and samples of the liquid and vapor phases of this material were then collected at this temperature.

The liquid collected under a water-cooled condenser was characterized by the following distillation analysis: 50 64056 Temperature ° C Distilled%

125 O

255 10 284 19 310 29 325 38 326 48 342 58 352 67 366 77 372 87 390 95

The liquid sample, collected from a liquid nitrogen trap, was dried to remove water and then analyzed and found to contain xylene, styrene, toluene, benzene, pentane, pentadiene, cyclopentadiene, cyanophenadiene, butadiene, propylene methylene and methylene methylene hydrocarbons. The gaseous component of the trapped liquid nitrogen was dried and analyzed by mass spectrometry and gas chromatography. After correction for absence, this gaseous component of the two samples was found to have the following average composition (concentrations expressed in mole percent): hydrogen 88.23% \ methane 4.62% \ ethylene 3.09% \ propylene 1.22% \ ethylene 0.55% \ • ethane 0.41 butene 0.36% \ benzene 0.35% '»butadiene 0.31%', carbon dioxide 0.14% \ pentadiene 0.13% \ pentene 0.13% \ propane 0.12%; carbon monoxide 0.12% \ cyclopentadiene 0.10% \ methyl-pentadiene 0.06% ·, cyclohexane 0.03% \ butane 0.03% \ methylacetylene 0.02% and toluene 0.02%.

Example VIII

Partial steam reforming of gas oil

A gas oil identical to the gas oil used in Example VII was partially reconstituted (by a reforming method) with steam in a gas wall reactor in two substantially identical experiments. In both of these experiments, the gas oil was introduced into the reactor in the form of a mist by spraying it through a spray nozzle.

Hydrogen was used as a running curtain, a sweep gas and a spray gas at a rate of about 140 l / min. for each purpose.

64056

In both experiments, the reactor tube was initially heated to 1815 ° C, hydrogen was introduced into the sweep gas inlet and into the collector chamber at approximately the rates used during the experiment. Gas oil was then introduced into the reactor at a rate of about 0.95 liters per minute along with steam, which was introduced at a rate of about 1.8 kg per minute, corresponding to a carbon / steam molar ratio of about 1.0: 1.6. Under the thermal load of gas oil and steam, the reactor temperature dropped to 1593 ° C. The exhaust gas temperature just below the outlet was about A55 ° C. Samples were collected and processed in the same manner as in Example VII.

The liquid collected from below the water-cooled condenser in the first run was characterized by the following distillation analysis: Temperature ° C Distilled% 250 0 305 10 325 20 335 30

335 AO

3AA 50 356 60 362 70 362 80 380 90

In the second run, a sample of the liquid component collected from the liquid nitrogen trap was heated to 10 ° C, dried to remove water, and then qualitatively analyzed. The result sample was found to contain toluene, benzene, pentene, pentadiene, cyclopentadiene, butene, butadiene, naphthenic, xylene, styrene and higher molecular weight hydrocarbons. The portion of the original sample, the liquid nitrogen trap that was volatile at 10 ° C, was dried and analyzed by gas chromatography and mass spectrometry and found to have the following composition after correction for the presence of air (concentrations are expressed in mole percent): ethylene 36 , 85%; propylene 23.22%; acetylene 8.56% \ ethane 7.99% '»hydrogen A, Al%; butene A, Al% butadiene 3.50%; propane 2, A7%; methane 2.10%, methylacetylene 1.98%; benzene 52 6 4 0 5 6 1.56% i pentadiene 0.62% 3 pentene 0.62 cyclopentadiene 0.49% l carbon dioxide 0.37% \ butane 0.25% 3 methylpentadiene 0.25% \ cyclohexane 0 , 13% and toluene 0.04%.

Example IX

Thermal dissociation of sawdust

Sawdust, a typical lignin-containing by-product, was thermally dissociated in a reactor tube 6l at 1870 ° C while forcing hydrogen through the porous wall of the tube at 140 rpm. Sawdust was fed to the reactor at a rate of about 22.7 kg per hour. The pyrolysis binders comprised a finely divided carbon black similar to that produced when dissociating methane, gaseous products from the dissociation of volatile compounds, and coarse-grained carbonization in which the fibrous structure of the original wood was substantially intact.

Example X

Silicon carbide abrasives made of quartz

Quartz sand with a particle size distribution in the range of -50 mesh to + 100 mesh was introduced into the reactor tube 6l through inlet 121 at a rate of 4.5 kg per hour. Methane was added simultaneously through the inlet 91 of the reactor tube at a rate of 28 l / min. The reactor tube temperature was maintained at 1870 ° C. Nitrogen was sprayed into the reactor tube through a porous wall at a rate of 14 ° 1 / min. to form a gas wall. The powder was dropped from the reactor tube and collected in the funnel below.

The powdered product was abrasive enough to easily scratch the glass, indicating that it contained silicon carbide. Microscopic examination of the powder showed that it consisted of silica particles covered with a shell formed of amorphous carbon and thin plates of crystalline silicon carbide.

Example XI

Production of aluminum carbide

A stoichiometric mixture of aluminum powder and elemental carbon was prepared for the following planned reaction: 4 Al + 3 C - ^ Al ^ Cj (1) This mixture was introduced into the reactor at a rate of about 4.5 kg per hour. Reactor tube 6l was maintained at 1870 ° C and hydrogen was forced through the porous wall of the 53 6 4 0 5 6 reactor tube at a rate of 140 Ι / min. The reaction gave an amorphous, gray-brown substance which was trapped below the reactor tube. A sample of the gray-brown product was mixed with 0.1 N HCl. A gas evolved which burned with the characteristic yellow flame of methane, indicating that the following reaction had taken place between the product and hydrochloric acid:

Al 2 Cl 2 + 12 HCl (aq) → 3 CH 4 (g) + AlCl 2 aq) (2) The sample was completely dissolved in hydrochloric acid to give a clear solution. Since elemental carbon was used as a starting material and is insoluble in 0.1 N HCl, this indicated that aluminum and carbon reacted quantitatively in a gas-walled reactor to form aluminum carbide.

To investigate the feasibility of producing aluminum carbide in a gas wall reactor from aluminum chloride and carbon, anhydrous AlCl 2 was placed in a carbon crucible and heated until sublimed. The aluminum chloride vapor was mixed with the hydrogen stream and the resulting stream was then passed over a layer of carbon black. The arc lamp was focused on the surface of the carbon layer and this heated the area of the layer to 999 ° C as measured by an optical pyrometer. Small orange crystals formed just downstream of the heated zone, indicating that the aluminum chloride had reacted with carbon and hydrogen to form aluminum carbide and hydrogen chloride according to the following reaction formula: 4 AlClj + 3C + 6 H2 - »AlIjjCj + 12 HCl (3)

When the orange crystals were added to 0.1 N HCl, the crystals dissolved and a gas evolved which burned with a yellow flame characteristic of methane.

Because this procedure simulates a reaction that can be accomplished in a gas wall reactor by reacting aluminum chloride with carbon and hydrogen (produced by thermal dissociation of a gaseous or liquid hydrocarbon), this brings to mind a new way to produce methane (1) by reacting aluminum chloride with a low hydrocarbon hydrogen chloride and (2) quenching the reaction product in water so that the resulting hydrochloric acid hydrolyzes the aluminum carbide to produce methane and aluminum chloride, which in turn can be recycled through the process.

54 64056

Example XII

Reduction of ferric oxide with hydrogen

To demonstrate the utility of a gas wall reactor in reducing metal ores, pure ferric oxide (-100 mesh) was fed to the reactor at a rate of 15.9 kg per hour while hydrogen was forced through the porous wall at a rate of 140 l / min. Hydrogen acted here both as a gas wall former and as a reducing agent for iron oxide. The reactor tube was maintained at 1870 ° C as measured by focusing the optical pyrometer on the glowing inner wall of the tube. The temperature of the reactants in the reactor tube was found to be 1510 ° C as measured by an optical pyrometer. A gray powder formed which was collected in a funnel under the reactor tube. The outlet temperature just below the reactor tube outlet was measured to 315 ° C.

The product was a pure iron powder which tended to be spontaneously flammable at a temperature of about 149 ° C when freshly prepared. Examination of the powder under a microscope showed that it was formed of small spherical particles, which indicated that the iron had been in the molten state during its passage through the reactor tube.

Example XIII

Thermal Dissociation of Hydrogen Sulfur and Methane Using a gas wall reactor, hydrogen sulfide was reacted in situ with carbon formed by thermal dissociation of methane to form carbon disulphide and hydrogen. The experiments were performed at two different temperatures, namely 1635 ° C and 1760 ° C. In both cases, temperatures were measured by focusing the optical pyrometer on the incandescent reactants in the reactor tube, with the carbon particles from the dissociation of methane being the main incandescent materials in the reaction mixture. Hydrogen was forced through the porous wall of the reactor tube at a rate of 140 l / min. to act as a curtain gas. Hydrogen sulphide at a rate of 9.1 / min. and methane at 28 rpm was mixed together and introduced into the reactor tube. The gas mixture was at room temperature at the inlet to the reactor tube. Carbon black as a target was added to initiate the reaction, although after the reaction had begun, it was self-sustaining and no more carbon black was needed.

Samples of the gaseous components of the products of the two experiments were analyzed by mass spectrometry. The analytical results are given in the following table, the concentrations are expressed in molar percentages: 55 64056

Compound Reaction temperature

1635 ° C to 1760 ° C

Hydrogen 83,974 88,560

Methane 11,379 6,230

Acetylene 1.68l 2.281

Ethylene 1,397 1,519

Hydrogen sulphide 1,021 0,813

Carbon dioxide 0.296 0.160

Sulfur carbon 0.216 0.403

Benzene 0.036 0.034

Although all of the above examples were carried out in the gas-walled reactor shown in Figures 1A-1B, even better results can be obtained by using the gas-walled or liquid-walled reactor of Figures 6A-6D with appropriate modifications (if necessary) to handle solid feeds. The use of process variable control systems makes it possible to accurately identify and maintain optimal operating conditions. If such a control system includes a digital calculator, the search for optimal operating conditions can be performed automatically.

>

'I

l

Claims (20)

A method for carrying out a high temperature chemical reaction by passing the reactants centrally through a reactor tube, to protect the inner wall of which a gas envelope is formed by passing through its porous wall an inert radiation substantially passing gas into the reactor tube and by heating the material or materials in the reactor tube by means of high intensity radiation to initiate and maintain the reaction, characterized in that the refractory tube consisting of refractory material is heated along at least a portion of its length, the radiant energy being reflected against the reactor. at a distance the same surrounding heat shield, wherein the materials in the reactor tube are heated by absorbing radiant heat emitted by the reactor tube. 2. A method according to claim 1, characterized in that where the reactants control all the radiation passing material there is in the reactor tube at least initially a radiation absorbing melt material for raising the temperature inside the tube. Method according to Claim 1 or 2, characterized in that the radiant energy absorbing melt material is conducted along the reactor's path of travel before the reactants are introduced into the reactor tube, the yaryid melt material absorbs sufficient radiant energy to raise the reactor's temperature to the level required for the reactor to reach the level of reactor. 4. A process according to claim 2, characterized in that the radiation energy absorbing melt material is deactivated after the desired reaction has been initiated. Method according to claim 1 or 2, characterized in that radiant energy is directed to a limited length of the predetermined path of movement of the reactants. Process according to claim 1 or 2, characterized in that the reaction products and any remaining reaction components are cooled immediately after the reaction components have left the reaction chamber, in order to end the desired chemical reaction and prevent other undesired chemical reactions. A gas or fluid wall high temperature reactor for carrying out the process according to any of claims 1-6, which reactor comprises (A) a reactor tube (61; 401) having an inlet end (62; 402) and an outlet end (63; 403). ) and whose inner space forms a reaction chamber (65; 411, 4o4, 422), which reactor tube (61; 401) is made of a porous refractory material which emits radiant energy, the pores of refractory materials having a diameter allowing a uniformly sufficient flow of inert fluid through the wall of the tube to form a protective housing on the radially inert surface of the reactor tube (61; 401); (B) a fluid-tight tubular pressure vessel (70; 201, 301, 405, 501) surrounding the reactor tube (61; 401) and restricting an inert fluid collection chamber (85; 4θβ) between the reactor tube (61; 401) and the pressure vessel (70; 201, 301, 405, 501), the inlet and outlet ends (62, 63; 402, 403) of the reactor tube (61; 401) being closely delimited from the collection chamber (85; 406), the pressure vessel (70; 201 , 301, 405, 501) has an inlet (83; 4o8) for introducing an inert fluid; (C) injection components (90; 214, 232) for reaction components located and provided for feeding at least one reaction component into the reactor chamber (65; 411, 404, 422) through the inlet end (62; 402) of the reactor tube (61; 401), characterized the reactor comprising (D) an electric heater (100a-100f; 317, 318, 302a-302c, 319) located radially spaced from the reactor tube (61; 401), and (E ) a peripheral heat shield (120; 410) located in the pressure vessel (70; 201, 301, 405> 501) in a radial direction outside the heater (100a-100f; 317, 3-18, 302a-302c, 319), which heat shield (120; 410) is arranged to reflect radiant energy into the recuperator tube (6l; 401). 62 6 4 0 5 6 8. A reactor according to claim 7, characterized in that the refractory material of the reactor tube (401) is a fibrous tissue having a large number of pores of such diameter that it permits a sufficient flow of inert fluid through the wall of the tube to form a protective housing on the reactor tube. (401) radially inner surface. 9. Reactor according to claim 7 or 8, characterized in that it comprises means for introducing a radiation-absorbing melt material into the reaction chamber (65; 411, 404, 422) to coincide with at least a portion of the reaction path of the reaction components. 10. Reactor according to claim 9, characterized in that the melt material is liquid. 11. Reactor according to claim 9, characterized in that the melt material is a gas which absorbs path lengths of the electromagnetic spectrum from about 100 microns to about 0.01 microns. 12. Reactor according to claim 9, characterized in that the milling material consists of atomized coal powder. 15. Reactor according to claim 9, characterized in that the meter is a fixed element which is placed in the reaction chamber along at least part of the path of movement of the reactants. Reactor according to claim 13, characterized in that said solid element is made of koi. 15. Reactor according to claim 7, characterized in that the porous material consists of graphite, koi, sintered stainless steel, sintered tungsten, sintered molybdenum, thorium oxide, magnesium oxide, zinc oxide, alumina or zirconia.