US3554708A - Process and apparatus for heating titanium tetrachloride vapor - Google Patents

Process and apparatus for heating titanium tetrachloride vapor Download PDF

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Publication number
US3554708A
US3554708A US712769A US3554708DA US3554708A US 3554708 A US3554708 A US 3554708A US 712769 A US712769 A US 712769A US 3554708D A US3554708D A US 3554708DA US 3554708 A US3554708 A US 3554708A
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United States
Prior art keywords
tubes
titanium tetrachloride
vapor
platinum
conduits
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US712769A
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English (en)
Inventor
Peter M Jones
Dennis Read
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Laporte Titanium Ltd
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Laporte Titanium Ltd
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Filing date
Publication date
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/07—Producing by vapour phase processes, e.g. halide oxidation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H3/00—Air heaters
    • F24H3/02—Air heaters with forced circulation
    • F24H3/04—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element
    • F24H3/0405—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element using electric energy supply, e.g. the heating medium being a resistive element; Heating by direct contact, i.e. with resistive elements, electrodes and fins being bonded together without additional element in-between
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/40—Heating elements having the shape of rods or tubes
    • H05B3/42—Heating elements having the shape of rods or tubes non-flexible

Definitions

  • the present invention provides apparatus for heating titanium tetrachloride vapor which comprises an inlet conduit, an outlet conduit and a plurality of tubes arranged in parallel relationship and in communication with the said conduits. Means also is provided for heating the tubes.
  • the inlet and outlet conduits and the tubes are constructed of platinum or an alloy of platinum with rhodium, ruthenium or iridium.
  • the invention also provides a process for heating titanium tetrachloride Vapor which comprises fiowing the vapor from an inlet conduit to an outlet conduit through a plurality of tubes arranged in parallel with one another while heating the tube's.
  • the titanium tetrachloride vapor may be heated either alone or in admixture with the vapor of one or more other chlorides, for example, aluminum chloride.
  • the inlet and outlet conduits and the tubes are preferably constructed from a platinum-rhodium alloy containing rhodium within the range of from 5% to 25% by weight, preferably, within the range of from 10% to 15% by Weight, based on the Weight of the alloy. If platinumportion of ruthenium or iridium, respectively, s advan- ICC tageously within the range of from 5% to 25 (preferably, 10% to 15 by weight, based on the weight of the alloy.
  • platinum or a platinum alloy as the material of construction makes it possible to heat the titanium tetrachloride Vapor to temperatures substantially in excess of 500 C., which is about the maximum temperature that can be satisfactorily achieved using other metals such as, for example, nickel.
  • the tubes may be treated for this purpose by the electrolytic deposition of platinum black upon them and in this Way the emissivity (which is, of course, proportional to the absorptivity at any given temperature) can be increased, in the case of platinum, from the Value of 0.17 for polished platinum to about 0.6, but it falls to about 0.4 if the platinum is subjected to prolonged heating.
  • the tubes are treated for this purpose by roughening their outer surfaces with a file or an emery cloth. In this Way, the emissivity of platinum can again be increased to about 0.6 and this value is maintained even after prolonged heating.
  • tubes constructed of platinumrhodium or platinum-ruthenium or platinum-iridium alloys are treated by the deposition of platinum black or by roughening the outer surfaces of the tubes as hereinbefore mentioned.
  • the tubes are heated by passing an electric current through them, it is of course desirable that the emissivity of the outer surfaces of the tubes be as low as possible and therefore these surfaces are then preferably polished.
  • the tubes may be heated by passing a hot gas over them, but they are preferably heated by means of an electric furnace within which the tubes are situated. Instead of heating the tubes externally, each tube may be heated by passing an electric current through it.
  • the use of electric heating Whether effected externally or by passing an electric current through the tubes, has the advantage, as comparedwith the use of a hot gas stream, of avoiding the risk that the tubes may be attacked by sulphur frequently contained in the hot gas stream or as a result of reducing conditions obtained in the hot gas stream. Precautions should, of course, be taken to prevent air from entering the apparatus with the titanium tetrachloride vapor to keep corrosion to a minimum.
  • each tube may be clamped adjacent to the outlet conduit and connected to the inlet conduit by means of a flexible bellows, the conguration of the tube being such that thermal expansion and o contraction of the tube in operation results in movement of the end of the tube that is adjacent to the inlet conduit substantially along the axis of the bellows.
  • the tubes are U-shaped and hang from the conduits so that they are free to expand and contract in a vertical direction.
  • each tube may be Within the range of from da inch to 1 inch.
  • the optimum thickness of the wall of each tube depends to some extent on the internal diameter of the tube, but it is usually preferable to use a thickness within the range of from 0.01 inch to 0.05 inch.
  • the wall thickness is preferably about 0.02 inch.
  • the invention also provides a process and apparatus for the manufacture of titanium dioxide by the vapor-phase oxidation of titanium tetrachloride wherein the titanium tetrachloride is preheated by apparatus comprising an inlet conduit, an outlet conduit and a plurality of tubes connected in parallel between the said conduits as hereinbefore specified, the inlet and outlet conduits and the said tubes being constructed of platinum or an alloy of platinum with rhodium, ruthenium or iridium.
  • titanium tetrachloride vapor may be supplied to the inlet conduit at a temperature of about 160 C. and heated in the tubes to a temperature of about 1000 C.
  • the tubes To preheat the titanium tetrachloride to a ternperature of 1000 C., the tubes must be heated to a temperature approaching 1100 C. and when the tubes are heated by situating them within an electric furnace, the temperature of the furnace walls will normally need to be maintained at a temperature within the range of from 1200 C. to 1350 C.
  • FIG. 1 is an end elevation view of the apparatus
  • FIG. 2 is a side elevation view of the apparatus
  • FIG. 3 is a plan view of the apparatus.
  • the apparatus comprises a straight inlet conduit 1 mounted with its axis horizontal and a straight outlet conduit 2 mounted with its axis parallel to, and lying in the same horizontal plane as, the axis of the inlet conduit 1.
  • Each of the conduits 1 and 2 is formed with a row of approximately equally spaced apertures in its underside.
  • the number of apertures in the conduits 1 and 2 are the same and the arrangement is such that, for each of the apertures in one of the conduits, a vertical plane at right angles to the axis of the conduit passing through the center of the aperture also passes through the center of an aperture in the other conduit.
  • the conduits 1 and 2 are interconnected by a plurality of U-tubes 3, which are connected in parallel and which hang vertically downwards from the conduits and are each so shaped that the height of the tube is much greater than the horizontal separation between the limbs.
  • One end of each tube 3 is in register with an aperture in the conduit 1, and the other end of the tube is in register with the adjacent aperture in the conduit 2, thus providing communication between the conduits 1 and 2.
  • the axes of the limbs of each U-tube 3 lie in a vertical plane that Cal i is at right angles to the axes of the conduits 1 and 2.
  • the conduits 1 and 2 and the tubes 3 are constructed of a platinum-rhodium alloy having a rhodium content of 10% by weight based on the weight of the alloy.
  • the external surfaces of the tubes 3 are roughened by tiling to increase the emissivity of these surfaces to about 0.6.
  • the conduits 1 and 2 are each supported from above by members 4 which support each conduit at points spaced apart along the length thereof.
  • the portion of each member 4 that passes underneath the conduit 1 or 2 that it is supporting is concave upwardly and is provided on its upper surface with a layer of ceramic refractory material 5 (for example, sintered alumina) upon which the conduit rests.
  • ceramic refractory material 5 for example, sintered alumina
  • the apparatus is adapted for use in an electric furnace having a lining of a refractory material and provided with U-shaped silicon carbide resistance elements.
  • the titanium tetrachloride vapor to be heated is supplied to the inlet conduit 1 through the open end 6 thereof and then through the U-tubes 3, where it is heated, to the outlet conduit 2 of which the end 7 is open, the pressure drop across the U-tubes being suiciently high to ensure that the rate of flow of the titanium tetrachloride is, when the apparatus has the dimensions hereinbefore stated to be suitable, about pounds per hour through each U-tube.
  • Apparatus for heating titanium tetrachloride vapor which comprises an inlet conduit, an outlet conduit, and a plurality of tubes arranged in parallel relationship with one another and in open communication between the said conduits, and means for heating the tubes, said inlet and outlet conduits and said tubes being constructed of metals selected from the group consisting of platinum and alloys of platinum with rhodium, ruthenium or iridium.
  • inlet and outlet conduits and the tubes are constructed from a platinum-rhodium alloy containing rhodium within the range of from 5% to 25% by weight based on the weight of the alloy.
  • each tube is clamped adjacent to the outlet conduit and connected to the inlet conduit by flexible bellow means.
  • a process for heating titanium tetrachloride vapor which comprises flowing said vapor from an inlet conduit to an outlet conduit through a plurality of tubes arranged in parallel relationship with one another while heating said tubes, the inlet and outlet conduits and said tubes being constructed of a metal selected from the group consisting of platinum and alloys of platinum with rhodium, ruthenium or iridium.
  • each tube is heated by passing an electric current through it.
  • um tetrachloride vapor is supplied to the inlet conduit at 15 23 02y 252; 106 300 165 81; 203 .g7

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Furnace Details (AREA)
  • Catalysts (AREA)
US712769A 1967-03-29 1968-03-13 Process and apparatus for heating titanium tetrachloride vapor Expired - Lifetime US3554708A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB04220/67A GB1219573A (en) 1967-03-29 1967-03-29 Improvements in and relating to heating titanium tetrachloride vapour

Publications (1)

Publication Number Publication Date
US3554708A true US3554708A (en) 1971-01-12

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ID=10037215

Family Applications (1)

Application Number Title Priority Date Filing Date
US712769A Expired - Lifetime US3554708A (en) 1967-03-29 1968-03-13 Process and apparatus for heating titanium tetrachloride vapor

Country Status (6)

Country Link
US (1) US3554708A (en:Method)
BE (1) BE712999A (en:Method)
DE (1) DE1767069C3 (en:Method)
FR (1) FR1563276A (en:Method)
GB (1) GB1219573A (en:Method)
NL (1) NL165947C (en:Method)

Also Published As

Publication number Publication date
DE1767069A1 (de) 1971-08-12
DE1767069B2 (de) 1979-06-28
NL6804249A (en:Method) 1968-09-30
NL165947C (nl) 1981-06-15
NL165947B (nl) 1981-01-15
DE1767069C3 (de) 1980-02-28
FR1563276A (en:Method) 1969-04-11
BE712999A (en:Method) 1968-07-31
GB1219573A (en) 1971-01-20

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