KR20080036036A - Installation for synthesis of the titanium dioxide and the plasma chemical reactor - Google Patents

Abstract

The installation for synthesis of titanium dioxide contains a plasmotron, connected to a source of oxygen, a plasma chemical reactor connected to a consumable vessel of titanium tetrachloride, a hardening chamber having in its bottom portion a pneumatic pulsed generator, a heat exchanger of "tube in tube" type, which is coupled coaxially and directly to an output radial tube of the hardening chamber, a cyclone, having a quenching chamber and a filter. Injectors are mounted in the median zone of the body of plasma chemical reactor to ensure injection of titanium tetrachloride; beneath that level, a circular muzzle is located, having a form of a annular channel adjacent to the wall meant for the injection of a protection gas (oxygen) forming a thin whirlwind layer of a protection gas curtain.

Description

Titanium Dioxide Synthesis Apparatus and Plasma Chemical Reactor {INSTALLATION FOR SYNTHESIS OF THE TITANIUM DIOXIDE AND THE PLASMA CHEMICAL REACTOR}

FIELD OF THE INVENTION The present invention relates to a process for producing powdered materials, and in particular, to a process used to produce titanium dioxide by chloride technology.

In the background, a synthetic product separation block consisting of a series of connected plasmatrons connected to an oxygen source or an oxygen containing gas source, a plasma chemical reactor connected to a supply tank of titanium tetrachloride, a curing chamber, a heat exchanger, and a cyclone and a filter. A device for synthesizing titanium dioxide by a chloride technique comprising RU 2057714 C1, CO1G23 / 047, 1996 is known. Disadvantages of the known scheme are the habitual clogging of the heat exchanger and the deposition of titanium dioxide into the cyclone, which requires the preparation of a cleaning suspension, several outlets for titanium dioxide complicate the structure and workability of the entire apparatus. Worsens.

An axially-symmetrical case having water-cooled walls and an outlet at the bottom, a plasma generator located on top of the case, and a batch injection valve mounted to the intermediate body of the case, which faces the outlet, Plasma chemical reactors for producing titanium dioxide by chloride technology (RU 2052908 C1, H05H1 / 42, 1996; WO 97/19895 A1, H05H1 / 42, 1997) are also known. The production capacity of hard by-products on the walls of the reactor produced below the injection valves during the production of titanium dioxide causes problems in process conditions, which leads to deterioration of extractable products and deterioration of the reliability of the reactor operation. In total, a titanium dioxide synthesis apparatus by this chloride technique would be a disadvantage of this reactor structure.

It is an object of the present invention to improve the working efficiency and reliability of the synthesis apparatus of titanium dioxide and to improve plasma chemistry without promoting the production of tubercles on the walls of the reactor in the jet region of atomization of precursors by injection valves. To improve the operating characteristics of the reactor.

To achieve this object, the present invention provides a series of connected plasmatrons connected to an oxygen source or an oxygen-containing gas source, a plasma chemical reactor connected to a supply tank of titanium tetrachloride, a curing chamber, a heat exchanger, and a cyclone and a filter. In the titanium dioxide synthesizing apparatus comprising a composite product separation block consisting of: wherein the curing chamber is a radially positioned outlet nozzle having a cylindrical case where a bunker of coarse fraction of titanium dioxide is connected at the conical bottom; And an air-impact generator, the trunk being located at the bottom of the cylindrical case coaxially and radially opposite the radial outlet nozzle, the heat exchanger being in the form of a tube such as << pipe in pipe >> and Directly opened coaxially to the radial outlet nozzle of the curing chamber And an input portion of the cyclone separation synthesis products block connected to the heat exchanger is the case and the branch axis is positioned in a coaxial relationship between pipes in the following ratio of the geometric parameters of the - and having a symmetrical damping chamber,

d / D = (0.1 / 0.7),

Where d is the maximum diameter of the damping chamber,

D is the diameter of the cylindrical case.

In addition, the inlet nozzle for the re-containing gas of the bag filter of the composite product separation block is connected to the branch pipe of the cyclone, and the outlet nozzle for the conserved particles is connected to the peripheral region of the upper part of the cylindrical case of the cyclone by a communication path. It is connected to, characterized in that consisting of a conical bottom portion having a pneumatic device of titanium dioxide.

The solution according to the invention has an axially symmetrical case having water-cooled walls and an outlet in the bottom, the upper part of which is connected to a plasma generator, and an arrangement of titanium tetrachloride located in the middle body of the case and the jet facing the outlet ( 10. A plasma chemistry reactor comprising batch nozzles, wherein the annular jet on the wall of the casing is directly connected in coaxial relationship to the outlet of the wall annular channel, the annular collar of the collector ring for protective gas input and A tangential hole formed by an inner wall and spaced at equal intervals, the outlet plane of the annular jet being located at a next distance below the nozzle outlets of the spray nozzles spaced at equal intervals,

H <1/2 (D ₁ -D ₂ ) ctg (α / 2),

Where H is the outlet plane of the annular jet and above the outlets of the injection valves.

Distance between tooth levels;

D ₁ is the diameter of the case;

D ₂ is a circular diameter in which the injection valves are located;

α is the spray-cone angle of the injection valves.

Preferably, one central injection valve should be located in the intermediate body of the case, mainly the lower-power reactor.

The plasma reactor-plasmatron- may be equipped with cathode and anode packs, which are positioned at each other and serve as oxygen supply nozzles.

By providing an annular jet having a collector ring located downwardly from the notch outlets of the injection valve, thereby producing a thin layer of gas mist in the protective gas in the form of a rotating flow at the wall of the reactor case below the position of the injection valve. This prevents the unreacted drops of reagent from reaching the walls and promotes the formation of nodules, but the light gauge eliminates the adverse effects of the process in the space of the reactor.

By placing an air-impact generator in the curing chamber and directly connecting a heat exchanger of tubular structure such as << pipe in pipe >> in coaxial relationship to the radial outlet nozzle of the curing chamber, an air pulse is passed through the trunk of the generator. Periodically from the channel of the heat exchanger to the channel of the heat exchanger, which is under the effect of destruction of the deposit of the titanium dioxide, precluding the possibility of clogging the heat exchanger with titanium dioxide, Effective removal is achieved by powder-gas flow at a weight ratio—mass flow density of 5 to 80 kg / m ² sec.

In addition, the structure of the cyclone with the damping chamber has no additional dissolution capacity, which increases the efficiency of promoting the deposition of fine particles of titanium dioxide powder by 82 to 97%. It is also possible to reduce the number of outlets of titanium dioxide by connecting the outlet nozzles for the receiving particles of the bag filter to the peripheral region of the upper part of the cylindrical case of the cyclone using a passage path, and further simplifying the structure and The work reliability of the apparatus can be improved.

1 shows a titanium dioxide synthesis apparatus according to the present invention.

2 is a longitudinal schematic cross-sectional view of a plasma chemistry reactor.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is an enlarged view of a portion B of FIG. 2.

The apparatus shown in FIG. 1 is a series of connected plasmatrons 1 to which an oxygen source 2 is connected, a plasma chemical reactor 3 connected to a supply tank 4 by an input pump 5 of titanium tetrachloride, A curing chamber 6 with an air-impact generator 7, a straight pipe with gentle rounded interfaces or a square coiled straight pipe, having a tubular structure such as < pipe > A heat exchanger 8 directly coaxially connected to the radial outlet nozzle 9 of the curing chamber 6, and a cyclone 11, a tangential inlet nozzle 12 connected to the heat exchanger 8 and a bag filter ( And a synthetic product separation block 10 having 13). The exhaust trunk 14 of the air-impact generator 7 is the bottom of the cylindrical case of the curing chamber 6 which is coaxially and radially opposite to the inlet of the radial outlet nozzle 9 and the heat exchanger 8. It is installed in the wall of the department. The cyclone 11 has an axially-symmetrical conical-cylindrical damping chamber 15, the maximum diameter << d >> of which ranges from 0.1 to 0.7 of the diameter << D >> of the cylindrical case and the pneumatic The device 16 is located at the conical bottom. The branch pipe 17 of the cyclone 11 is connected to the inlet nozzle 18 for the ash-laden gas of the bag filter 13, the outlet nozzle 19 for its retaining particles being It is connected to the peripheral region of the upper part of the cylindrical case of the cyclone 11 by a passage path 20 (screw conveyor).

The plasma chemistry reactors 3, 2, 3 and 4 have a water-cooled top 21 and an outlet 25 in which the cathode and anode packs 22, 23 of the 2-spool plasma generator-plasmonron 1 are located. And a bottom portion 24 located in the central body of the case (in the bottom of the top 21), the batch injection valve 26 being directed to the outlet 25 of the liquid titanium tetra Branch pipes 27 for input of chloride are provided. A collector ring 28 for protecting gas input is located between the top and bottom portions 21, 24 of the case, the top 21 of the case is provided below, and the band 29, fillet is equidistantly spaced. An inner wall 30 of the collector rings 28 having tangential holes spaced apart by means of which an annular jet 32 in the form of an annular channel is located in direct coaxial relationship with the outlet 25. In addition, the outlet plane of the annular jet 32 is located at the next distance below the nozzle outlets of the spray nozzles 26 spaced at regular intervals,

H <1/2 (D ₁ -D ₂ ) ctg (α / 2),

Where H is the distance between the outlet plane of the annular jet and the position level of the outlets of the injection valves;

D ₁ is the diameter of the case;

D ₂ is a circular diameter in which the injection valves are located;

α is the spray-cone angle of the injection valves.

The present invention is carried out as follows.

In the cathode 23 and anode 24 packs of the plasma generator-plasmonron 1, oxygen heated up to the plasma state is supplied from a source 2 in the bridge of the plasmatron 1. A jet of oxygen plasma enters the interior space of the upper portion 21 of the case of the plasma chemistry reactor 3 from the plasma tron 1, in which a flow of oxygen plasma is formed which is filled in all cross-sectional areas of the case. Where it goes around the injection valves 26 to the outlet 25. Liquid titanium tetrachloride (TiCl ₄ ) is supplied from the supply tank (4) to the injection valves (26) via the branch pipes (27) by an air pump (4) under constant pressure, and a protective gas-oxygen -Is fed to the collector ring 28 through the branch pipe 33. In addition, the oxygen jets flowing through the tangential holes 31 of the collector ring 28 are mixed to tangentially contact the walls of the case of the reactor, and the band 29 allows the distribution of radial oxygen jets to Do not enter the space of the reactor. The injection valves 26 spray titanium tetrachloride, and the particulate jet is mixed with the oxygen plasma to form a reaction flow in which the titanium tetrachloride is volatilized and the steam is acidified to titanium dioxide. The protective gas-oxygen-flow from the axial annular jet 32 forms a thin layer of gas mist in the jet region of the particulates of the injection valves, causing a large drop of titanium tetrachloride to the wall of the case of the reactor. Prevents here, there is no volatilization time, the contact with the wall of the case of the reactor forms a solid by-product to improve the working stability and reliability of the reactor, to improve the operating characteristics of the titanium dioxide synthesizing device and received products Promote quality improvement.

A gas consisting of chlorine and abundant oxygen-a powder-gas stream of particles of titanium dioxide of size 0.2 to 1.0 micron in chlorine-titanium dioxide synthesis as a gas suspension-the reaction product leaving the reactor enters into the curing chamber (6), Partial cooling is performed here, and the deposition of coarse particles of titanium dioxide collected in the bunker 34 of coarse particles attached to the conical bottom of the cylindrical case of the curing chamber 6 is processed. The powder-gas flow of the reaction product from the curing chamber 6 through the radial outlet nozzle 9 is directed towards the straight inlet of the heat exchanger 8 in which their final cooling is carried out. The powder-gas flow exiting the heat exchanger 8 through the tangential inlet nozzle 12 enters the top of the cylindrical case of the cyclone 11, under centrifugal force effect, from the powder-gas flow into the conical bottom. Deposition of titanium dioxide entering occurs. The mixed powder-gas flow from the case of the cyclone 11 enters the damping chamber 15, where the tangential velocity of the flow in the wall of the chamber is higher than the tangential velocity in the wall of the case so that fine powder of titanium dioxide Provides a more complete deposition of The chlorine-gas with residual titanium dioxide coming out of the damping chamber 15 through the separation pipe 17 is fed to an inlet nozzle 18 for ash-laden of the bag filter 13. , Here, separation of chlorine-gas from residual titanium dioxide is carried out. The chlorine-gas from the bag filter 13 is provided to the consumer and the titanium dioxide trapped from the outlet nozzle 19 for conserved particles via the passageway 20 (screw conveyor) is a cylindrical case of the cyclone 11. Towards the peripheral area of the top of the. The fine particles of titanium dioxide that sink to the conical bottom of the cyclone 11 are transferred to the next process by the pneumatic device 16.

During the synthesis of titanium dioxide, an exhaust trunk 14 is installed on the wall of the bottom of the cylindrical case of the curing chamber 6, the curing chamber of the radial outlet nozzle 9 and thus of the heat exchanger 8. Coaxially and radially opposed to the input-opening straight line, the air-impact generator 7 periodically sends pressure and negative pressure pulses to the flow inner channel of the heat exchanger to provide titanium dioxide on the inner wall of the heat exchanger 8. Destroying the deposit and removing the particles of titanium dioxide from the heat exchanger 8 is performed by a powder-gas flow with the following flow parameters:

G / F = ρu = 5 / 80kg / m ² sec,

Where G / F is the weight ratio of the powder-gas flow

ρu is the mass flow density of the powder-gas flow

G is the weight ratio of the cooled medium through the channel, kg / sec

F is the cross-sectional area of the channel of the heat exchanger

ρ is the density of the cooled medium, kg

u is the flow rate of the cooled medium.

In addition, the blockage of the channel of the heat exchanger 8 occurs at ρu <5gk / m ² sec, and the hydraulic resistance of the heat exchanger 8 increases rapidly at ρu> 80gk / m ² sec.

The operating conditions of the production process of titanium dioxide, which ensures the working efficiency and reliability of the device, are given in Table 1, and the work-effective measurements of the cyclones are given in Table 2.

TABLE 1

Plasma Trone's Power (kW) Consumption of Components Yield rate of titanium dioxide (kg / h) Variable of heat exchanger Mass Flow Density ρu (kg / m ² sec) Presence of blockage in the channel of the heat exchanger TiCl ₄ (kg / h) Titanium dioxide (kg / h) Total (kg / h) Diameter of channel (m) Cross section (m2) 55 106 22 0.0375 44 0.1 7.85 x 10 ^-3 4.85 existence 60 117 25 0.0394 49 0.1 7.85 x 10 ^-3 5.00 absence 120 235 50 0.0792 98 0.1 7.851 x 10 ^-3 10.08 absence 240 470 100 0.1583 196 0.1 7.85 x 10 ^-3 20.16 absence 150 290 60 0.097 120 0.05 2.00 x 10 ^-3 48.5 absence 240 475 100 0.16 200 0.05 2.00 x 10 ^-3 80 absence

TABLE 2

Case of cyclone Damper diameter d (m) Ratio (d / D) Dust fixing efficiency Blockage of cyclone Diameter D (m) Height (m) 3 3 1.2 0.4 97 absence 3 3 0.3 0.1 82 absence 3 3 0.24 0.08 75 absence 3 3 2.25 0.75 80 absence 3 3 2.1 0.7 87 absence 2 1.6 0.4 0.2 85 absence 3 3 1.5 0.5 95 absence 1.6 1.6 0.6 0.4 97 absence

According to the present invention, the operating efficiency and reliability of the plasma chemical reactor can be improved and the operating characteristics of the plasma chemistry reactor can be improved without promoting the generation of nodules on the walls of the reactor within the jet region of atomization of the precursors by the injection valves. Can be improved.

Claims (3)

Dioxide comprising a series of connected plasmatrons connected to an oxygen source or an oxygen-containing gas source, a plasma chemical reactor connected to a supply tank of titanium tetrachloride, a curing chamber, a heat exchanger, and a composite product separation block consisting of cyclones and filters Titanium Synthesis Apparatus, The curing chamber has a cylindrical case in which the bunkers of titanium dioxide coarse particles are connected at the conical bottom, and is a radially located outlet nozzle, the trunk of which is located at the bottom of the cylindrical case coaxially and radially opposite the radial outlet nozzle. Further comprising an air-shock generator positioned, said heat exchanger being in the form of a tube such as a << pipe in pipe >> and connected directly in a coaxial relationship to the radial outlet nozzle of said curing chamber, an input being connected to said heat exchanger The cyclone of the composite product separation block to be connected has an axis-symmetric damping chamber positioned coaxially between the case and the branch pipe at a ratio of the following geometrical parameters, d / D = (0.1 / 0.7), Where d is the maximum diameter of the damping chamber, D is a titanium dioxide synthesizing apparatus, characterized in that the diameter of the cylindrical case. The method of claim 1, The inlet nozzle for the re-containing gas of the bag filter of the synthetic product separation block is connected to the branch pipe of the cyclone, and the outlet nozzle for the conserved particles is connected to the peripheral region of the top of the cylindrical case of the cyclone by a communication path. Titanium dioxide synthesis apparatus, characterized in that consisting of a conical bottom portion having a pneumatic device of titanium dioxide. An axially-symmetrical case having water-cooled walls and an outlet in the bottom and connected to a plasma generator, the top being located in the intermediate body of the case, the jet being spray nozzles for the batch of titanium tetrachloride directed towards the outlet. In the plasma chemical reactor, The annular jet on the wall of the case is formed to be directly connected in the coaxial relationship to the outlet of the wall annular channel, formed by the annular collar and the inner wall of the collector ring for protective gas input, the tangential hole spaced at equal intervals And the outlet plane of the annular jet is located at a next distance below the nozzle outlets of the spray nozzles spaced at regular intervals, H <1/2 (D ₁ -D ₂ ) ctg (α / 2), Where H is the outlet plane of the annular jet and above the outlets of the injection valves. Distance between tooth levels; D ₁ is the diameter of the case; D ₂ is a circular diameter in which the injection valves are located; α is the spray-cone angle of the injection valves.

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