Scar removal system and method for oxidation reactor

Abstract

The invention discloses a scar removal system and method for an oxidation reactor, scars are removed by adopting scar removal sand, the scars cannot be dissolved in titanium dioxide slurry, the sand and a base material can be completely separated, and the product quality and yield can be ensured; and the scar removing sand is subjected to slurry flushing or water washing separation, the subsequent slurry can be conveniently treated and is free of pollution, the scar removing sand is continuously and hermetically recycled, a large amount of raw material cost is saved, the scar removing efficiency can be improved, and the cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to a scar removal system and method for an oxidation reactor, in particular to a scar removal system and method for an oxidation reactor used for producing titanium dioxide by a chlorination process. Background Art

[0002] Oxidation is an important process in the production of titanium dioxide by the chloride process. High-temperature gaseous titanium tetrachloride and high-temperature oxygen react instantly in the oxidation reactor to produce titanium dioxide. Titanium dioxide needs to be rapidly cooled in the cooling duct, otherwise the high-temperature titanium dioxide will stick to the rear end of the oxidation furnace and the inner wall of the cooling duct in the form of aerosol, quickly blocking the system and causing shutdown. Therefore, it is necessary to continuously add scar removers to the cooling pipe at the rear end of the oxidation furnace to remove scars, increase the heat exchange efficiency of the cooling duct, and allow the titanium dioxide to cool rapidly.

[0003] Currently, it is more common to use rock salt to remove scars, but adding rock salt to the system will cause quality problems with titanium dioxide, and the separation of rock salt and titanium dioxide will make subsequent water treatment difficult. As the load increases, the amount of rock salt added will also increase significantly and be difficult to recover. When removing scars, employees need to transport, hoist, and add rock salt every day, which consumes a lot of manpower and time. The scar removal efficiency is low and the cost will also increase significantly. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies in the prior art and provide an oxidation reactor scar removal system and method, which uses scar removal sand to remove scars. The sand and base material can be completely separated, thereby ensuring product quality and yield. The sand is used in a continuous closed cycle, and the subsequent slurry can be conveniently processed and pollution-free, thereby improving scar removal efficiency and significantly reducing costs.

[0005] In order to achieve the above-mentioned purpose, an oxidation reactor scar removal system of the present invention comprises an oxidation reactor, a No. 1 silo, and a cooling duct placed in a water tank. The oxidation reactor is provided with a gas pipe, a combustion chamber, a reaction cylinder and a cooling pipe, and the outlet of the cooling pipe is connected to the inlet of the cooling duct; it is characterized in that: the upper end of the No. 1 silo is connected to the exhaust fan, and its lower end is connected to the intermediate silo below through valve I, the lower end of the intermediate silo is connected to the lower silo below through valve II, a pressurizing pipe is connected to both the intermediate silo and the lower silo, and a control valve is provided between the pressurizing pipe and the intermediate silo; the No. 1 silo is connected to the upper part of the intermediate silo through a bypass pipe, and a bypass valve is provided on the bypass pipe; the lower end of the lower silo is connected to the cooling pipe through a star-shaped discharger and a discharge pipe, and one end of the discharge pipe is connected to the air supply pipe; the outlet of the cooling duct is connected to the feed port of the bag filter through a pipeline, and the bag The discharge port of the filter is connected to the feed port of the pulping tank. The pulping tank is provided with a liquid inlet pipe. The discharge port of the pulping tank is connected to the feed port of the drum screen through a pipeline. The front section of the bottom of the drum screen is connected to a pulp discharge pipe, and the rear section of the bottom is connected to a spray liquid tank through a pipeline. There are several spray heads in the drum screen, and the spray heads are all connected to the spray pipe. A water washing tank is provided below the discharge port of the drum screen. The water washing tank is provided with a water injection pipe and a self-circulation pipe. A self-circulation pump is provided on the self-circulation pipe. The self-circulation pipe is connected to the spray liquid tank through a liquid separation pipe, and the spray liquid tank is connected to the spray pipe through a spray pump; the discharge port of the water washing tank is connected to the feed hopper of the drum dryer through a screw conveyor, and the discharge port of the drum dryer is connected to the inlet of the No. 2 silo through a belt conveyor. The bottom of the No. 2 silo is connected to the return silo, and the return silo is connected to the inlet of the No. 1 silo through a return pipe. The return silo is provided with an air blowing pipe; A scar removal method for an oxidation reactor using the above system comprises the following steps: A) loading scar removal sand into a return silo, introducing high-pressure nitrogen through an air blowing pipe, and starting an exhaust fan at the same time to transport the scar removal sand to silo No. 1 and discharge the nitrogen; B) closing the control valve, opening the bypass valve to balance the pressure of silo No. 1 and the intermediate silo, opening valve I, lowering the scar removal sand into the intermediate silo, and closing the bypass valve and valve I; C) opening the control valve and valve II, introducing high-pressure nitrogen through a pressure pipe, the pressure of which is greater than the pressure in the oxidation reactor, and closing the control valve and valve II after a sufficient amount of scar removal sand enters the lower silo. The scar removal sand is then discharged into the cooling pipe and the cooling duct by nitrogen through a star-shaped discharger to remove scars from the inner walls of the two pipes; D) a mixture of scar removal sand, titanium dioxide, chlorine and nitrogen enters a bag filter for Separation, most of the gas is discharged from the exhaust pipe at the upper end of the bag filter, scar removal sand and titanium dioxide are transported to the pulping tank by air pressure, and desalted water is continuously introduced into the pulping tank to dissolve titanium dioxide for pulping; E) Titanium dioxide slurry and scar removal sand are transported to the drum screen by air pressure, and the spray pump is started to spray and separate the titanium dioxide slurry and scar removal sand. Most of the titanium dioxide slurry is discharged from the discharge pipe, and a small part of the low-concentration titanium dioxide slurry enters the spray liquid tank, and the scar removal sand is sent to the washing tank; F) Desalted water is continuously injected into the washing tank, and the self-circulating pump is started to wash the scar removal sand and separate the titanium dioxide again, and part of the titanium dioxide slurry enters the spray liquid tank; The scar removal sand is sent to the feed hopper of the drum dryer by a screw conveyor and preliminarily dehydrated; G) The scar removal sand is sent to the No. 2 silo and the return silo after drying to achieve the recycling of the scar removal sand.

[0006] The scar removing sand used in the present invention is quartz sand or silicon dioxide, which will not dissolve in the titanium dioxide slurry. The sand and the base material can be completely separated, which can ensure the product quality and yield. The sand is separated by slurry washing or water washing, and the subsequent slurry can be conveniently processed without pollution. The scar removing sand is used in a continuous closed cycle, which saves a lot of raw material costs, can improve scar removal efficiency and greatly reduce costs. As a further improvement of the present invention, the upper end of the No. 1 silo is connected to an exhaust fan through a dust collector, which can prevent sand and dust leakage and reduce pollution; As a further improvement of the present invention, the water tank is provided with a circulation pipe connecting the bottom and the upper part thereof, and the circulation pipe is provided with a circulation pump; the cooling water in the water tank can be circulated to improve the cooling effect of the cooling conduit; As a further improvement of the present invention, a temperature sensor is provided on the pipeline at the feed port of the bag filter, the motor of the star-shaped feeder is a variable frequency motor, and both the temperature sensor and the variable frequency motor are connected to the controller; in step C), the material temperature at the feed port of the bag filter is detected by the temperature sensor, and if the temperature exceeds the preset temperature range, the controller increases or decreases the speed of the variable frequency motor, and increases or decreases the feed amount controlled by the star-shaped feeder, which can ensure scar removal efficiency and improve the degree of automation; As a further improvement of the present invention, a stirrer is provided in the pulping tank to improve the uniformity of the pulp; As a further improvement of the present invention, the two ends of the self-circulating pipe are respectively connected to the high position and the low position on the opposite sides of the water washing tank, and the discharge port of the water washing tank is connected to the feed hopper of the drum dryer through a screw conveyor arranged obliquely upward; the water washing effect of the scar removing sand can be improved, and automatic preliminary dehydration can be achieved; In summary, the present invention adopts scar removal sand to remove scars, and the sand and base material can be completely separated, which can ensure product quality and yield. The sand is used in a continuous closed cycle, and the subsequent slurry can be easily processed without pollution, which can improve the scar removal efficiency and greatly reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 Schematic diagram of the structure of an embodiment of the present invention. DETAILED DESCRIPTION

[0008] In order to more clearly understand the purpose, technical solutions and beneficial effects of the present invention, the present invention is further described below in conjunction with the accompanying drawings.

[0009] like Figure 1As shown, an oxidation reactor scar removal system of this embodiment includes an oxidation reactor 1, a No. 1 silo 6, and a cooling duct 8 placed in a water tank 7. The oxidation reactor 1 is provided with a gas pipe 2, a combustion chamber 3, a reaction tube 4 and a cooling pipe 5. The outlet of the cooling pipe 5 is connected to the inlet of the cooling duct 8. The water tank 7 is provided with a circulation pipe 9 connecting the bottom and the top thereof, and the circulation pipe 9 is provided with a circulation pump 10. The upper end of the No. 1 silo 6 is connected to an exhaust fan 12 through a dust collector 11, and the lower end thereof is connected to an intermediate silo 14 below through a valve 13. The lower end of the intermediate silo 14 is connected to a lower silo 16 below through a valve 15. A pressurizing pipe 17 is provided. It is connected to the intermediate silo 14 and the lower silo 16, and a control valve 18 is provided between the pressure pipe 17 and the intermediate material 14; the No. 1 silo 6 is connected to the upper part of the intermediate silo 16 through a bypass pipe 19, and a bypass valve 20 is provided on the bypass pipe 19; the lower end of the lower silo 16 is connected to the cooling pipe 5 through a star-shaped discharger 21 and a discharge pipe 22, and the motor of the star-shaped discharger 21 is a variable frequency motor, and one end of the discharge pipe 22 is connected to the air supply pipe 23; the outlet of the cooling duct 8 is connected to the feed port of the bag filter 24 through a pipeline, and a temperature sensor 25 is provided on the pipeline at the feed port of the bag filter 24, and the temperature sensor 25 and the variable frequency motor are connected to the control The bag filter 24 is connected to the feed port of the pulping tank 26, the pulping tank 26 is provided with a liquid inlet pipe 27, the pulping tank 26 is provided with an agitator 28, the discharge port of the pulping tank 26 is connected to the feed port of the drum screen 29 through a pipeline, the front section of the bottom of the drum screen 29 is connected to a pulp discharge pipe 30, and the rear section of the bottom is connected to a spray liquid tank 31 through a pipeline, the drum screen 29 is provided with a plurality of spray heads 32, the spray heads 32 are all connected to the spray pipe 33, a washing tank 35 is provided below the discharge port of the drum screen 29, the washing tank 35 is provided with a water injection pipe 36 and a self-circulation pipe 37, and the two ends of the self-circulation pipe 37 are respectively connected to the washing tank 36 and the self-circulation pipe 37. The high position and the low position on the opposite sides of the tank are connected, and a self-circulation pump 38 is provided on the self-circulation pipe 37. The self-circulation pipe 38 is connected to the spray liquid box 31 through a liquid separation pipe, and the spray liquid box 31 is connected to the spray pipe 33 through a spray pump 34; the discharge port at the bottom of the washing tank 35 is connected to the feed hopper of the drum dryer 40 through a screw conveyor 39 inclined upward, and the discharge port at the bottom of the drum dryer 40 is connected to the inlet of the No. 2 silo 42 through a belt conveyor 41, and the bottom of the No. 2 silo 42 is connected to the return silo 43, and the return silo 43 is connected to the inlet of the No. 1 silo 6 through a return pipe 44, and the return silo 44 is provided with a blowing pipe 45; A scar removal method for an oxidation reactor using the scar removal system includes the following steps: A) loading scar removal sand into a return bin 43, introducing high-pressure nitrogen through the air blowing pipe 45, and starting the exhaust fan 12 at the same time to transport the scar removal sand to the No. 1 bin 6 and discharge the nitrogen; B) closing the control valve 18, opening the bypass valve 20 to balance the pressure of the No. 1 bin 6 and the intermediate bin 14, opening the valve 13, and lowering the scar removal sand into the intermediate bin 6, and then closing the bypass valve 20 and the valve 13; C) opening the control valve 18 and the valve 15, and introducing high-pressure nitrogen through the pressurized pipe 17, the pressure of which is greater than the pressure in the oxidation reactor 1, and a sufficient amount of scar removal sand enters the lower bin 16, then close the control valve 18 and the valve 15, the scar-removing sand is then fed through the star-shaped feeder 21 to control the feeding amount, and the nitrogen introduced through the air supply pipe 23 is output to the cooling pipe 5 and the cooling conduit 8 to remove the scars on the inner walls of the two pipes; the material temperature at the feeding port of the bag filter 24 is detected by the temperature sensor 35. If the temperature exceeds the preset temperature range, the speed of the variable frequency motor is increased or decreased by the controller to increase or decrease the feeding amount controlled by the star-shaped feeder 21; D) the mixture of scar-removing sand, titanium dioxide, chlorine and nitrogen enters the bag filter 24 for separation, and most of the gas is discharged from the exhaust pipe at the upper end of the bag filter 24, and the scar-removing sand and titanium dioxide are discharged by the gas The titanium dioxide slurry and the scar removing sand are transported to the slurry tank 26 by air pressure, and the titanium dioxide slurry and the scar removing sand are evenly stirred by the stirrer 28. E) The titanium dioxide slurry and the scar removing sand are transported to the drum screen 29 by air pressure, and the spray pump 34 is started to spray and separate the titanium dioxide slurry and the scar removing sand with the mixed slurry in the spray liquid tank 31 through the spray head 32. Most of the high-concentration titanium dioxide slurry is discharged from the slurry discharge pipe 30 and enters the subsequent treatment. A small part of the low-concentration titanium dioxide slurry enters the spray liquid tank 31, and the screened scar removing sand is sent to the washing tank 35. F) The washing tank 35 is continuously injected with water through the water injection pipe 36. Desalted water is used and the self-circulating pump 38 is started to wash the scar removing sand and separate a small amount of attached titanium dioxide again to form a titanium dioxide slurry with a lower concentration. The washing effect of the scar removing sand can be improved through the self-circulating pipe 37. At the same time, part of the titanium dioxide slurry enters the spray liquid tank 31 through the liquid separation pipe and mixes with the low-concentration titanium dioxide slurry in the early stage; the washed scar removing sand is sent to the feed hopper of the drum dryer 40 by the screw conveyor 39 and preliminarily dehydrated. The screw conveyor 39 arranged obliquely upward can realize automatic preliminarily dehydration; G) After being dried, the scar removing sand is sent to the No. 2 silo 42 and the return silo 43 by the belt conveyor 41 to realize the recycling of the scar removing sand.

[0010] The exhaust fan 12 can reduce the pressure in the No. 1 silo 6 to normal pressure, which is conducive to the scar removal sand in the return silo 44 entering the No. 1 silo 6; through the bypass pipe 19 and the bypass valve 20, a sufficient amount of scar removal sand can be intermittently discharged into the intermediate silo 14, so that the lower silo 16 can be continuously discharged into the oxidation reactor 1, ensuring the continuous scar removal and improving the scar removal effect and efficiency; in order to facilitate parking for maintenance, a valve 46 can also be set in front of the lower silo 16, and the lower silo 16 is connected to the upper part of the intermediate silo 14 through a bypass pipe, and a bypass valve 47 is provided on the bypass pipe, so that the air pressure in the two silos can be balanced during maintenance; The gas discharged from the exhaust pipe at the upper end of the bag filter 24 is mainly chlorine, which is sent to the chlorination furnace for reaction; the scar removal sand used in the present invention is quartz sand or silicon dioxide, which will not dissolve in the titanium dioxide slurry, and the scar removal sand is separated twice by slurry washing and water washing, and the sand and titanium dioxide (base material) can be completely separated, the yield of titanium dioxide is high, and the product quality can be guaranteed; the subsequent slurry can be conveniently handled and pollution-free, and the scar removal sand is used in a continuous closed cycle, which saves a lot of raw material costs, can improve scar removal efficiency and greatly reduce costs; The circulation pump 10 can realize the circulation of cooling water in the water tank 7, and improve the cooling effect of the cooling pipe 8; through the linkage of the temperature sensor 25, the controller and the star-shaped feeder 21, the amount of conveying and adding scar removal sand can be automatically controlled throughout the process, without manual operation, ensuring scar removal efficiency and improving the degree of automation; The above embodiments have been described, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments.

Claims

1. An oxidation reactor scar removal system, comprising an oxidation reactor, a No. 1 silo, and a cooling conduit placed in a water tank, wherein the oxidation reactor is provided with a gas pipe, a combustion chamber, a reaction cylinder, and a cooling conduit, wherein the outlet of the cooling conduit is connected to the inlet of the cooling conduit; characterized in that: The upper end of the No. 1 silo is connected to the exhaust fan, and the lower end is connected to the intermediate silo below through valve I. The lower end of the intermediate silo is connected to the lower silo below through valve II. A pressure pipe is connected to both the intermediate silo and the lower silo, and a control valve is provided between the pressure pipe and the intermediate silo. The No. 1 silo is connected to the upper part of the intermediate silo through a bypass pipe, and a bypass valve is provided on the bypass pipe. The lower end of the lower silo is connected to the cooling pipe through a star-shaped discharger and a discharge pipe, and one end of the discharge pipe is connected to the air supply pipe. The outlet of the cooling duct is connected to the feed port of the bag filter through a pipeline, and the discharge port of the bag filter is connected to the feed port of the pulping tank. The pulping tank is provided with a liquid inlet pipe, and the discharge port of the pulping tank is connected to the feed port of the drum screen through a pipeline. The front section of the bottom of the drum screen is connected with a slurry discharge pipe, and the rear section of the bottom is connected with the spray liquid box through a pipeline. There are several spray heads in the drum screen, and the spray heads are connected with the spray pipe. A water washing tank is provided below the discharge port of the drum screen. The water washing tank is provided with a water injection pipe and a self-circulation pipe. A self-circulation pump is provided on the self-circulation pipe. The self-circulation pipe is connected with the spray liquid box through a liquid separator, and the spray liquid box is connected with the spray pipe through a spray pump; the discharge port of the water washing tank is connected with the feed hopper of the drum dryer through a screw conveyor, and the discharge port of the drum dryer is connected with the inlet of No. 2 silo through a belt conveyor, and the bottom of No. 2 silo is connected with the return silo, and the return silo is connected with the inlet of No. 1 silo through a return pipe, and the return silo is provided with an air blowing pipe.

2. The oxidation reactor scar removal system according to claim 1, characterized in that: The upper end of the No. 1 silo is connected to the exhaust fan through a dust collector.

3. An oxidation reactor scar removal system according to claim 1 or 2, characterized in that: The water tank is provided with a circulation pipe connecting the bottom and the upper part thereof, and a circulation pump is provided on the circulation pipe.

4. The oxidation reactor scar removal system according to claim 3, characterized in that: A temperature sensor is arranged on the pipeline at the feeding port of the bag filter, the motor of the star-shaped feeder is a variable frequency motor, and both the temperature sensor and the variable frequency motor are connected to a controller.

5. The oxidation reactor scar removal system according to claim 4, characterized in that: A stirrer is arranged in the pulping tank.

6. The oxidation reactor scar removal system according to claim 5, characterized in that: The two ends of the self-circulating pipe are respectively connected to the high position and the low position on the opposite sides of the washing tank, and the discharge port of the washing tank is connected to the feed hopper of the drum dryer through a screw conveyor arranged obliquely upward.

7. A method for removing scars from an oxidation reactor using the system of claim 1, characterized in that The following steps are involved: A) Place the scar-removing sand in the return silo, introduce high-pressure nitrogen through the air blowing pipe, start the exhaust fan at the same time, transport the scar-removing sand to silo No. 1 and discharge the nitrogen; B) Close the control valve, open the bypass valve to balance the pressure of silo No. 1 and the intermediate silo, open valve I, and after the scar-removing sand is discharged into the intermediate silo, close the bypass valve and valve I; C) Open the control valve and valve II, and introduce high-pressure nitrogen through the pressure pipe. The pressure is greater than the pressure in the oxidation reactor. After a sufficient amount of scar-removing sand enters the discharge silo, close the control valve and valve II. The scar-removing sand is then discharged through the star-shaped discharger to control the discharge amount and then output to the cooling pipe and In the cooling duct, the inner walls of the two tubes are descaled; D) The mixture of descaling sand, titanium dioxide, chlorine and nitrogen enters the bag filter for separation, and most of the gas is discharged from the exhaust pipe at the upper end of the bag filter. The descaling sand and titanium dioxide are transported to the pulping tank by air pressure, and desalted water is continuously introduced into the pulping tank to dissolve titanium dioxide for pulping; E) The titanium dioxide slurry and descaling sand are transported to the drum screen by air pressure, and the spray pump is started to spray and separate the titanium dioxide slurry and the descaling sand. Most of the titanium dioxide slurry is discharged from the discharge pipe, and a small part of the low-concentration titanium dioxide slurry enters the spray liquid box, and the descaling sand is sent to the washing tank; F) Desalted water is continuously injected into the washing tank, and the self-circulating pump is started to wash the scar removing sand and separate the titanium dioxide again. Part of the titanium dioxide slurry enters the spray liquid tank; the scar removing sand is sent to the feed hopper of the drum dryer by the screw conveyor and initially dehydrated; G) The scar removing sand is sent to the No. 2 silo and the return silo after drying to achieve the recycling of the scar removing sand.

8. The method for removing scars from an oxidation reactor according to claim 7, characterized in that: The scar removing sand is quartz sand or silicon dioxide.

9. A method for removing scars from an oxidation reactor according to claim 7 or 8, characterized in that: In step C), the material temperature at the inlet of the bag filter is detected by a temperature sensor. If the temperature exceeds a preset temperature range, the speed of the variable frequency motor is increased or decreased by a controller.

10. The oxidation reactor scar removal system according to claim 9, characterized in that: The cooling water in the water tank is circulated to improve the cooling effect of the cooling conduit.

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