RU2305660C2 - Installation for the synthesis of the titanium dioxide and the method for the synthesis of the titanium dioxide - Google Patents

Abstract

FIELD: chemical industry; methods and installations for the synthesis of the titanium dioxide.

SUBSTANCE: the invention may be used for production of the powdery titanium dioxide using the chloride process engineering. The installations for the synthesis of the titanium dioxide contains: the plasmatron (1), to which the source (2) of oxygen or the oxygen-containing gas is connected; the plasma-chemical reactor (3) connected to the consumption tank (4); the device (5) used for feeding of the titanium tetrachloride; the hardening chamber (6); the single-pipe heat exchanger (8) of the "the pipe inside the pipe" type; the synthesis products separation block (10). The synthesis products separations block consists of the cyclone (11) and the screen (13). The hardening chamber has the cylindrical body, the cone bottom of which is connected to the hopper (21) with the coarse fractions of titanium dioxide and to the radially arranged outlet fitting pipe (9). The hardening chamber is additionally supplied with the pneumoimpulsive generator (7). The trunk (14) of the pneumoimpulsive generator is mounted in the lower part of the cylindrical body coaxially and diametrically opposite to the radial outlet fitting pipe (9). The cyclone of the synthesis products separation block, which inlet is connected to the heat exchanger (8,) is made with the axially symmetric leveling chamber (15), which is coaxially arranged between the body and the discharge pipe (17) at the following ratio of the geometrical parameters: d/D = (0.l÷0.7), where "d" is the maximum diameter of the leveling chamber; "D" is the diameter of the cylindrical body. The method of the synthesis of the titanium dioxide provides that refrigerating of the reaction products after the hardening chamber is exercised at the flow of the dust-gas stream in the single-pipe heat exchanger of the " a pipe inside the pipe" type with the mass speed - the mass stream density from 5 up to 80 kg/ms. The invention allows to boost efficiency and reliability of the installation operation for the synthesis of the titanium dioxide.

EFFECT: the invention allows to increase efficiency and reliability of the installation operation for the synthesis of the titanium dioxide.

3 cl, 1 dwg, 2 tbl

Description

The invention relates to the production of powder materials and can be used to produce titanium dioxide by chloride technology.

The prior art installation for the synthesis of titanium dioxide, containing serially connected plasmatron connected to a source of oxygen or oxygen-containing gas, a plasma-chemical reactor associated with the flow capacity of titanium tetrachloride, a quenching chamber, a heat exchanger and a unit for the separation of synthesis products, consisting of a cyclone and a filter (RU 2057714 C1, C01G 23/047, 1996). The main disadvantage of the known installation is the constant clogging of the heat exchanger and the cyclone with titanium dioxide deposits, requiring production stops for cleaning, and the presence of several discharge points of titanium dioxide, which complicates the design and reduces the overall operation efficiency of the installation.

There is also known a method for the synthesis of titanium dioxide, including the generation of a plasma of oxygen or an oxygen-containing gas, the introduction of titanium tetrachloride into the plasma stream and its decomposition in the plasma, sequential cooling of the reaction products formed in the quenching chamber and in the heat exchanger, and separation of the target product - titanium dioxide from the dust-gas stream (RU 2057714 C1, C01G 23/047, 1996). The disadvantage of this method is the possibility of clogging the heat exchanger with deposits of titanium dioxide, which reduces the efficiency of the process for producing titanium dioxide.

The invention is aimed at improving the efficiency and reliability of the installation and improving the process of synthesis of titanium dioxide.

The solution to this problem is provided by the fact that in the installation for the synthesis of titanium dioxide containing a serially connected plasmatron connected to a source of oxygen or an oxygen-containing gas, a plasma-chemical reactor associated with a flow capacity of titanium tetrachloride, a quenching chamber, a heat exchanger and a unit for the separation of synthesis products consisting of a cyclone and a filter, according to the invention, the quenching chamber is made with a cylindrical body, to the conical bottom of which a coarse fraction hopper is connected and titanium, and a radially arranged outlet pipe, and is additionally equipped with a pneumatic pulse generator, the barrel of which is installed in the lower part of the cylindrical body coaxially and diametrically opposite the radial outlet pipe, while the heat exchanger is made of a single tube-in-tube type and is coaxially directly connected to the radial outlet pipe quenching chamber, and the cyclone of the unit for the separation of synthesis products, the input of which is connected to the heat exchanger, is made with an axisymmetric soothing chamber, coax but placed between the housing and the outlet pipe in the following ratio of geometric parameters:

d / D = (0.1 ÷ 0.7),

where d is the maximum diameter of the stilling chamber;

D is the diameter of the cylindrical body.

In addition, the inlet pipe of dusty gas in the bag filter of the synthesis product separation unit is connected to the outlet pipe of the cyclone, and the outlet pipe of the captured particles is connected by a transport line to the peripheral zone of the upper part of the cylindrical body of the cyclone, which is made with a conical bottom equipped with pneumatic transport means of titanium dioxide.

Moreover, in the method for synthesizing titanium dioxide, which includes generating plasma of oxygen or an oxygen-containing gas, introducing titanium tetrachloride into the plasma stream and decomposing the latter in plasma, sequentially cooling the reaction products formed in the quenching chamber and in the heat exchanger, and separating the target product titanium dioxide from the dust-gas stream, according to the invention, the cooling of the reaction products after the quenching chamber is carried out during the flow of the dust and gas stream in a single-tube heat exchanger of the pipe-in-pipe type "with mass speed - mass flow density from 5 to 80 kg / m ² s.

The presence of a pneumatic pulse generator in the quenching chamber and the execution of the heat exchanger with a single tube-in-tube type pipe with its connection to the radial outlet pipe of the quenching chamber allows pneumatic pulses to be sent from the generator through its barrel to the heat exchanger channel to eliminate clogging of the heat exchanger, which causes the destruction of deposits titanium dioxide, and their effective removal from the heat exchanger channel is ensured in the claimed range of mass velocity - density the mass flow of the dust and gas stream from 5 to 80 kg / m ² s.

Moreover, the claimed design of the cyclone with the presence of a stilling chamber, which is an additional precipitator, improves the efficiency of the deposition of fine fractions of titanium dioxide powder to 82 ÷ 97%. In addition, the connection of the outlet pipe of the trapped bag filter particles to the transport line with the peripheral zone of the upper part of the cylindrical cyclone body reduces the number of titanium dioxide discharge points, which also helps to simplify the design and increase the reliability of the installation.

The drawing shows a diagram of an installation for the synthesis of titanium dioxide.

The installation contains a plasma torch 1, to which an oxygen source 2 is connected, a plasma-chemical reactor 3 connected to a supply tank 4 and a titanium tetrachloride feed means 5, a quenching chamber 6, equipped with a pneumatic pulse generator 7, a heat exchanger 8, which is made of a single-tube-in-tube type in the form straight pipe or rectangular turns of straight pipes with rounded corners and coaxially directly connected to the radial outlet pipe 9 of the quenching chamber 6, and the block 10 for the separation of synthesis products, including cyclone 11, tangent an inlet pipe 12 which is connected to a heat exchanger 8, and a bag filter 13. An exhaust barrel 14 of an air-pulse generator 7 is installed in the wall of the lower part of the cylindrical body of the quenching chamber 6 coaxially and diametrically opposite to the radial outlet pipe 9. The cyclone 11 is made with an axisymmetric conical-cylindrical soothing chamber 15, the maximum diameter "d" of which is from 0.1 to 0.7 from the diameter "D" of the cylindrical body, in the conical bottom of which a pneumatic vehicle is installed 16. Holes one tube 17 of the cyclone 11 is connected to the inlet pipe 18 of the dusty gas of the bag filter 13, the outlet pipe 19 of the captured particles of which is connected by a transport line 20 (screw conveyor) with the peripheral zone of the upper part of the cylindrical body of the cyclone 11.

The claimed invention is as follows.

In the plasma torch 1, a plasma of oxygen (or an oxygen-containing gas) is supplied from the source 2. The jet of oxygen plasma from the plasma torch 1 enters the plasma-chemical reactor 3, into which titanium tetrachloride is fed from the supply tank 4 by means of 5. In the plasma chemical reactor 3 during the interaction of titanium tetrachloride with an oxygen plasma, reaction-synthesis processes of titanium dioxide proceed. The reaction products are a gas suspension of particles of titanium dioxide with a size of 0.2 ÷ 1.0 μm in chlorine gas, consisting of chlorine and excess oxygen. The dust-gas stream of reaction products from the reactor 3 enters the quenching chamber 6, where they are partially cooled and a large fraction of titanium dioxide is deposited, which accumulates in the large fraction bin 21 attached to the conical bottom of the cylindrical body of the quenching chamber 6 and then sent for processing. The dust-gas flow of reaction products from the quenching chamber 6 through the radial outlet pipe 9 is directed to a heat exchanger 8, in which they are finally cooled during a flow with a mass velocity — mass flow density of 5 to 80 kg / m ² s. From the heat exchanger 8, the dust and gas stream through the tangential inlet pipe 12 enters the upper part of the cylindrical body of the cyclone 11, where titanium dioxide is deposited from the dust and gas stream into a conical bottom under the action of centrifugal forces. The swirling dust and gas stream from the cyclone body 11 enters the stilling chamber 15, at the wall of which the tangential flow velocity is much higher than the tangential velocity at the body wall, which ensures a more complete deposition of fine particles of titanium dioxide. Chlorine gas with residual titanium dioxide from the stilling chamber 15 is fed through a discharge pipe 17 to the inlet pipe 18 of the dusty gas of the bag filter 13, where chlorine gas is purified from the residual titanium dioxide. Chlorine gas from the bag filter 13 is supplied to the consumer, and the captured titanium dioxide from the outlet pipe 19 of the captured particles is sent through the transport line 20 (screw conveyor) to the peripheral zone of the upper part of the cylindrical body of the cyclone 11. Small particles of titanium dioxide deposited in the conical bottom of the cyclone 11 pneumatic vehicle 16 is passed for further processing.

During the synthesis of titanium dioxide, a pneumatic pulse generator 7, the exhaust barrel 14 of which is installed in the wall of the lower part of the cylindrical body of the quenching chamber 6, is coaxially and diametrically opposite to the radial outlet pipe 9 and, accordingly, the input - the initial section of the heat exchanger 8, periodically sends pressure and rarefaction pulses to the internal flow channel heat exchanger 8, which destroy the deposits of titanium dioxide on the inner walls of the heat exchanger 8, and the ablation of fractions of titanium dioxide from the heat exchanger 8 about exists by dust and gas flow with the following flow parameters:

G / F = ρu = 5 ÷ 80 kg / m ² s,

where G / F is the mass velocity of the dust and gas stream;

ρu is the mass flow density of the dust and gas stream, kg / m ² s;

G is the mass flow rate of the cooled medium through the channel, kg / s;

F is the cross-sectional area of the heat exchanger channel, m ² ;

ρ is the density of the medium to be cooled, kg / m ³ ;

u is the flow rate of the cooled medium, m / s;

Moreover, the presence of blockages in the channel of the heat exchanger 8 occurs at ρu <5 kg / m ² s, and at ρu> 80 kg / m ² s the hydraulic resistance of the heat exchanger 8 sharply increases.

Examples of the method are shown in table 1, and cyclone performance indicators are shown in table 2.

table 2 Cyclone body Damper Diameter d, m D / d ratio Dust deposition efficiency Presence of cyclone blockages Diameter D, m Height m 3 3 1,2 0.4 97 Are absent 3 3 0.3 0.1 82 Are absent 3 3 0.24 0.08 75 Are absent 3 3 2.25 0.75 80 Are absent 3 3 2.1 0.7 87 Are absent 2 1,6 0.4 0.2 85 Are absent 3 3 1,5 0.5 95 Are absent 1.6 1.6 0.6 0.4 97 Are absent

Claims (3)

1. Installation for the synthesis of titanium dioxide, containing a serially connected plasmatron connected to a source of oxygen or an oxygen-containing gas, a plasma-chemical reactor associated with a flow capacity of titanium tetrachloride, a quenching chamber, a heat exchanger and a unit for the separation of synthesis products, consisting of a cyclone and a filter, characterized in that the hardening chamber is made with a cylindrical body, to the conical bottom of which a hopper of a large fraction of titanium dioxide is connected, and a radially located outlet pipe com, and is additionally equipped with a pneumatic pulse generator, the barrel of which is installed in the lower part of the cylindrical body coaxially and diametrically opposite the radial outlet pipe, while the heat exchanger is made of a single tube-in-tube type and coaxially directly connected to the radial outlet pipe of the quenching chamber, and the cyclone of the separation unit synthesis products, the input of which is connected to the heat exchanger, is made with an axisymmetric stilling chamber coaxially placed between the body and the outlet pipe at the following ratio of geometric parameters d / D = (0.1-0.7), where d is the maximum diameter of the stilling chamber; D is the diameter of the cylindrical body. 2. Installation for the synthesis of titanium dioxide according to claim 1, characterized in that the inlet pipe of the dusty gas bag filter of the separation unit of the synthesis products is connected to the outlet pipe of the cyclone, and the outlet pipe of the captured particles is connected by a transport line to the peripheral zone of the upper part of the cylindrical body of the cyclone, which made with a conical bottom equipped with a pneumatic vehicle of titanium dioxide. 3. A method for synthesizing titanium dioxide, including the generation of a plasma of oxygen or an oxygen-containing gas, introducing titanium tetrachloride into the plasma stream and decomposing the latter in plasma, sequentially cooling the reaction products formed in the quenching chamber and in the heat exchanger, and separating the target product titanium dioxide from the dust and gas stream, characterized the fact that the cooling of the reaction products after the quenching chamber is carried out during the flow of the dust and gas stream in a single-tube heat exchanger of the pipe-in-pipe type with mass th speed-density of the mass flow from 5 to 80 kg / m ² s.