阅读说明：本技术 一种四氯化钛悬浮液回收四氯化钛的系统以及方法 (System and method for recovering titanium tetrachloride from titanium tetrachloride suspension ) 是由 吕天宝 侯宝瑞 乔仲春 王景顺 刘永松 王瑞涛 于 2019-10-29 设计创作，主要内容包括：一种四氯化钛悬浮液回收四氯化钛的系统,四氯化钛经除钒反应器进行矿物油除钒后,经悬浮液泵送至螺旋板换热器,经过螺旋板换热器降温后的除钒悬浮液进入到缓冲罐,缓冲罐顶部设置尾气排出装置,缓冲罐内的气态四氯化硅通过尾气装置排放到尾气处理系统,缓冲罐内的悬浮液通过悬浮液泵送至悬浮液离心机,在离心力的作用下使液固快速分离。(The utility model provides a titanium tetrachloride suspension retrieves system of titanium tetrachloride, titanium tetrachloride carries out mineral oil through removing the vanadium reactor and removes the vanadium after, sends to the spiral plate heat exchanger through the suspension pump, and the suspension that removes after the spiral plate heat exchanger cooling enters into the buffer tank, and the buffer tank top sets up tail gas eduction gear, and gaseous silicon tetrachloride in the buffer tank discharges the tail gas processing system through the tail gas device, and the suspension in the buffer tank passes through the suspension pump and sends to suspension centrifuge, makes the solid rapid separation of liquid under the effect of centrifugal force.)

1. A system for recovering titanium tetrachloride from titanium tetrachloride suspension comprises a vanadium removal reactor, a suspension liquid pump, a spiral plate heat exchanger, a buffer tank, a tail gas exhaust device, a suspension centrifuge, a chlorination furnace cooling conduit, a liquid pump, a cyclone separator and a chlorination furnace slag discharge groove, wherein after mineral oil vanadium removal is carried out on titanium tetrachloride through the vanadium removal reactor, the titanium tetrachloride is conveyed to the spiral plate heat exchanger through the suspension liquid pump, vanadium removal suspension liquid cooled through the spiral plate heat exchanger enters the buffer tank, the tail gas exhaust device is arranged at the top of the buffer tank, gaseous silicon tetrachloride in the buffer tank is discharged to a tail gas treatment system through the tail gas device, the suspension liquid in the buffer tank is conveyed to the suspension centrifuge through the suspension liquid pump, liquid and solid are rapidly separated under the action of centrifugal force, the liquid after liquid and solid separation is conveyed to the chlorination furnace cooling conduit through the liquid pump for spraying, and the liquid is gasified, the chlorination furnace cooling conduit is a U-shaped pipeline for enabling titanium tetrachloride mixed gas at the top of the chlorination furnace to enter a cyclone separator, the liquid is gasified and enters the cyclone separator, the titanium tetrachloride mixed gas in the cooling conduit is cooled, and the solid after liquid-solid separation is conveyed to a slag discharge groove of the chlorination furnace for neutralization treatment.

2. A method for recovering titanium tetrachloride using the titanium tetrachloride suspension recovery system as claimed in claim, which comprises the steps of:

step 1, pumping a suspension of titanium tetrachloride subjected to vanadium removal by mineral oil to a spiral plate heat exchanger, wherein the suspension of titanium tetrachloride subjected to vanadium removal by mineral oil refers to mud discharged from the bottom of a vanadium removal reactor after vanadium removal by mineral oil, the temperature of the suspension discharged from the bottom of the vanadium removal reactor is controlled to be 120-130 ℃, and the outlet temperature of the spiral plate heat exchanger is controlled to be 56.5-100 ℃;

step 2, enabling the vanadium-removing suspension subjected to cooling by the spiral plate heat exchanger to enter a buffer tank, wherein a tail gas discharge device is arranged at the top of the buffer tank, the suspension condensed by the spiral plate heat exchanger is the suspension discharged from the bottom of the vanadium-removing reactor after titanium tetrachloride is subjected to vanadium removal by mineral oil, the temperature of the suspension in the buffer tank is 56.5-100 ℃, and the gaseous silicon tetrachloride is discharged to a tail gas treatment system through the tail gas device at the top of the buffer tank because the vanadium-removing suspension contains a small amount of silicon tetrachloride and the boiling point of the silicon tetrachloride is 56.5 ℃, and the silicon tetrachloride in the buffer tank is gaseous;

step 3, starting a suspension centrifuge to work, pumping the suspension in the buffer tank to the suspension centrifuge, and rapidly separating liquid and solid under the action of centrifugal force, wherein the suspension centrifuge is a device for performing liquid-solid separation on the suspension through centrifugal force, and the suspension centrifuge allows the medium temperature to be-10-100 ℃;

step 4, pumping the liquid after liquid-solid separation to a chlorination furnace cooling conduit in a chlorination section for spraying, so that the liquid is gasified and enters a cyclone separator, wherein the chlorination furnace cooling conduit refers to a U-shaped pipeline through which titanium tetrachloride mixed gas at the top of the chlorination furnace enters the cyclone separator, the liquid is gasified and enters the cyclone separator, and meanwhile, the titanium tetrachloride mixed gas in the cooling conduit is cooled;

and 5, conveying the solid after liquid-solid separation to a slag discharging groove of the chlorination furnace for neutralization treatment.

3. The method according to claim 2, wherein in step 3, the suspension centrifuge is operated as follows:

step 3.1, collecting analog quantities of monitoring points from the site, wherein the analog quantities comprise motor temperature, bearing temperature, rotary drum torque and slag discharge moisture content;

step 3.2, judging the ready condition of the suspension centrifuge according to the analog quantity in the step 3.1, determining whether the suspension centrifuge can be started, comparing the collected field motor temperature and bearing temperature with a set alarm value and a stop value, alarming or continuing to stop if the collected field motor temperature and bearing temperature exceed the set alarm value and the stop value, otherwise, entering the step 3.3;

3.3, if the analog quantity meets the requirement, all the suspension centrifuges are in a ready state, and the suspension centrifuges are started;

3.4, starting the auxiliary motor to drive an auxiliary motor belt pulley, wherein the spiral blade runs at a low speed to remove residual substances possibly left in the last running, so that the situation of large starting vibration caused by uneven distribution of the residues possibly generated during the starting of the rotary drum is avoided, after the residual substances are removed, starting the main motor to drive the rotary drum to start running, and selecting a working mode after the stable rotating speed is reached, wherein the working mode is manual, automatic and stopping;

and 3.5, when the suspension centrifuge is closed, reducing the speed of the rotary drum, then continuously discharging the residual substances out of the machine by the spiral blade until the operator considers the satisfaction, separately and independently driving the rotary drum and the spiral blade, independently starting the spiral blade under the condition that the suspension centrifuge is blocked, and discharging the residual substances staying in the suspension centrifuge under the condition of low speed.

4.A method according to claim 3, characterized in that in said step 3.4:

during manual operation, an operator sets the rotating speed of the rotary drum and the rotating speed difference of the differential, and starts the suspension pump, so that manual operation is realized;

during automatic operation, measuring whether the concentration of fed materials is less than a given concentration, and adjusting and controlling the device to judge whether differential operation or zero differential operation is selected; when the feeding concentration is detected to be greater than the given concentration, the fuzzy controller of the adjusting control device performs differential operation based on a fuzzy control method;

when the operation is stopped, the suspension pump is closed, the main motor is closed, and the auxiliary motor is closed.

5. The method according to claim 4, wherein the zero differential speed operation of the automatic operation of step 3.4 comprises the following specific steps:

step 3.4.A1, when the suspension centrifuge operates at zero differential speed, the main motor increases the speed, the rotating drum increases the rotating speed to the preset rotating speed, the main motor drives the differential gear shell, the differential integrally rotates under the action of the clutch, the gear shell in the differential does not move relative to the input shaft, and the rotating drum and the helical blade rotate in the same direction at the same speed;

step 3.4.A2, turning off the auxiliary motor;

step 3.4.A3, opening a suspension pump;

step 3.4.A4, judging whether the torque of the rotary drum is larger than the preset upper limit torque, if so, entering step 3.4.A5, otherwise, returning to step 3.4. A3;

step 3.4.A5, in the separation process, feeding from the feeding pipe and discharging clear liquid from the liquid phase discharge port simultaneously and continuously, and when the sediment layer settled in the rotary drum is accumulated to a certain thickness, closing the suspension pump and stopping feeding and discharging liquid;

step 3.4.A6, starting the auxiliary motor under the full-speed operation condition to drive the input shaft of the differential mechanism, and enabling the helical blade to rotate at a preset speed;

step 3.4.A7, discharging the sediment from a solid discharge port of the rotary drum;

and 3.4.A8, judging whether the torque of the rotary drum is smaller than the preset lower limit torque, if so, returning to the step 3.4.A2, and otherwise, returning to the step 3.4. A7.

6. The method according to claim 4, wherein the step 3.4 fuzzy control method in automatic operation is specifically:

the physical parameters of the suspension are changed along with the time, wherein the concentration is a dynamic parameter, and under a fixed separation parameter, the separation effect performance is changed by the change of the concentration; meanwhile, the moisture content of the suspension can fluctuate due to the change of the input flow of the suspension, when the feed concentration is greater than the given concentration, the suspension centrifuge performs differential operation, the rotating speed difference is adjusted in real time by using a fuzzy control method according to the change of the moisture content of the discharged slag, and the control object is the moisture content of the settled slag; the executive component is a main motor driving the rotary drum; the measuring element is a turbidimeter, measures the moisture content of the separated sediment, converts the moisture content into a voltage signal, and then amplifies and filters the voltage signal; the fuzzy controller fuzzifies a signal sampled by the turbidimeter, fuzzy operation is carried out on the fuzzy quantity to obtain fuzzy output quantity, then the output quantity is defuzzified to obtain accurate quantity, and the frequency converter controls the main motor to output power of the execution element;

the fuzzy controller stores the established offline fuzzy control lookup table in a PLC memory according to a certain rule, and when the fuzzy controller performs real-time control, the precise quantity obtained after sampling is subjected to level quantization to obtain corresponding fuzzification discourse field elements, a quantized value of the output control quantity is obtained through table lookup, and the quantized value is multiplied by a scale factor to obtain the final precise control quantity.

7. The method according to claim 6, wherein the fuzzy control method is specifically:

step 3.4.B1, determining the structure of the fuzzy controller;

step 3.4.B2, determining language variables;

the method specifically comprises the following steps:

step 3.4.B2.1, setting sediment given humidity as c_dIf the actual sediment humidity is measured to be c, the sediment humidity error is e,

e＝c_d-c，

the linguistic variable is E, the domain of discourse is X { -3, -2, -1,0, +1, +2, +3}, and the fuzzy subset on the domain of discourse is

{ negative large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), positive large (PB) }, respectively, which respectively represent the currently measured actual humidity c of the sediment relative to the given humidity c of the sediment_dIs extremely high, very high, just in time, very low;

and 3.4.B2.2, wherein the variable quantity of the sampling values before and after the sediment humidity error is ec: ec is c₂-c₁，

The linguistic variable is EC, the domain is Y { -2, -1,0, +1, +2}, and the fuzzy subset on the domain is

{ negative large (NB), Negative Small (NS), Zero (ZO), Positive Small (PS), positive large (PB) } respectively represent the change c in the current sediment humidity₂-c₁The rapid decrease, invariance, increase and rapid increase;

step 3.4.B2.3, output the controlled variable U, the linguistic variable is U, the domain Z { -3, -2, -1,0, +1, +2, +3}, the fuzzy subset on the domain is

{ negative large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM) and positive large (PB) }, which respectively represent the actions of the control execution mechanism, namely large reduction amount of the rotating drum rotating speed, small reduction amount of the rotating drum rotating speed, unchanged rotating drum rotating speed, small acceleration amount of the rotating drum rotating speed, and large acceleration amount of the rotating drum rotating speed;

step 3.4.B3, establishing a linguistic variable assigned value table as shown below;

TABLE 1 linguistic variable E assignment Table

The table is for different linguistic variables E and fuzzy subsets

table 2 linguistic variables EC assignment table

The table is based on different linguistic variables EC and fuzzy subsets

TABLE 3 linguistic variable U assignment Table

The table is for different linguistic variables U and fuzzy subsets

step 3.4.B4, accumulating according to expert knowledge and experience of skilled operators, giving out a fuzzy control rule, and when the error is large or large, selecting the change of the control quantity to quickly reduce the error as much as possible and eliminate the error; when the error is small, the stability of the system is considered besides the error is eliminated, unnecessary overshoot and even oscillation of the system are prevented, and a fuzzy rule table is established according to a fuzzy control rule, as follows:

TABLE 4 fuzzy rule Table

The table is the fuzzy value of the linguistic variable U under the conditions of different linguistic variables E and EC;

step 3.4.B5, synthesizing and reasoning all possible situations one by one according to the quantization levels of the linguistic variable E and the EC discourse domain, calculating all corresponding output values by adopting a weighted average method fuzzy solving method, combining the output values with tables 1-4, and synthesizing a fuzzy control lookup table as follows:

TABLE 5 fuzzy control look-up table

The table is a control value of the output control quantity u under the conditions of different linguistic variables E and EC; and 3.4.B6, outputting the control quantity u through a scale conversion output frequency converter, and further controlling the rotating speed of the main motor, thereby realizing fuzzy control.

Technical Field

The invention belongs to the field of titanium tetrachloride recovery, and particularly relates to a system and a method for recovering titanium tetrachloride from a titanium tetrachloride suspension.

Background

Titanium tetrachloride is the most important raw material for producing titanium sponge and titanium white by chlorination process. At present, industrial titanium tetrachloride is mainly produced by a chlorination process in the world, raw materials adopted by the chlorination process contain certain impurities, titanium dioxide is chlorinated, meanwhile, impurity elements are also chlorinated to generate corresponding chlorides, and the impurities directly influence the quality of titanium sponge, so that crude titanium tetrachloride must be purified and refined to be used for producing titanium sponge and titanium white. Since the vanadium impurities in crude titanium tetrachloride exist mainly as vanadium trioxide (V0C13) with a boiling point (127 ℃) very close to that (136 ℃) of titanium tetrachloride, the separation of vanadium from titanium tetrachloride by a rectification method is difficult. The invention is applied to the recovery of titanium tetrachloride in mineral oil vanadium removal slurry.

The difficulty of recovering titanium tetrachloride mud compared with the common solid-liquid separation is mainly reflected in that the whole process is required to be carried out in a closed state, and titanium tetrachloride contacts air to hydrolyze to emit white smoke, so that respiratory tracts are stimulated and human health is harmed; titanium tetrachloride splashes on the skin or in the eyes, and hydrolyzes to burn the skin and the eyes, so that skin scald which is difficult to cure or vision loss and even blindness are caused; and the slurry has high viscosity, and the development of a recovery process and equipment needs to properly solve the problems of sealing and high viscosity.

One of the existing methods for treating the titanium tetrachloride slurry containing vanadium, which is generated from vanadium-removing slurry, is to firstly adopt hydrolytic sedimentation, then utilize an ore pulp evaporation furnace to recover titanium tetrachloride, and add lime to neutralize the residual vanadium-containing residue. The method has the disadvantages of complicated control process, serious environmental pollution caused by slag discharge after evaporation of ore pulp, and low recovery rate of titanium tetrachloride.

In another common method, the vanadium-containing titanium tetrachloride slurry thickener is directly thrown into a boiling chlorination furnace after being settled, titanium tetrachloride in the slurry is vaporized by using the waste heat generated by the chlorination furnace, and the generated titanium tetrachloride gas enters a rear system along with the produced titanium tetrachloride mixed gas to be collected. Although the method can better recover titanium tetrachloride, the titanium tetrachloride cannot be continuously added due to the temperature control of the chlorination furnace, so that the titanium tetrachloride cannot be continuously recovered, and meanwhile, the titanium tetrachloride is uniformly added at a small flow when the titanium tetrachloride is added into the chlorination furnace, so that the amount of the recovered titanium tetrachloride is limited, and a large amount of slurry cannot be treated.

The separation of sludge by a spiral discharge sedimentation centrifuge is a nonlinear process, the nonlinear change mainly comes from the separation characteristics of the centrifuge, the physical properties of the separated particles and the operation conditions of particle separation, and the same separation effect cannot be achieved due to given control variables in different time of the separation process, so that the separation process is difficult to optimize and the separation effect is improved by adopting classical control.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the invention aims to provide a method for recovering titanium tetrachloride from titanium tetrachloride mineral oil vanadium-removing slurry in the chlorination titanium dioxide production, the method can realize continuous treatment of the mineral oil vanadium-removing slurry, and the separation efficiency of titanium tetrachloride and vanadium-containing solids in the mineral oil vanadium-removing slurry is high, so that the titanium tetrachloride can be fully recovered.

The technical scheme of the invention is as follows: a system for recovering titanium tetrachloride from titanium tetrachloride suspension comprises a vanadium removal reactor, a suspension liquid pump, a spiral plate heat exchanger, a buffer tank, a tail gas exhaust device, a suspension centrifuge, a chlorination furnace cooling conduit, a liquid pump, a cyclone separator and a chlorination furnace slag discharge groove, wherein after mineral oil vanadium removal is carried out on titanium tetrachloride through the vanadium removal reactor, the titanium tetrachloride is conveyed to the spiral plate heat exchanger through the suspension liquid pump, vanadium removal suspension liquid cooled through the spiral plate heat exchanger enters the buffer tank, the tail gas exhaust device is arranged at the top of the buffer tank, gaseous silicon tetrachloride in the buffer tank is discharged to a tail gas treatment system through the tail gas device, the suspension liquid in the buffer tank is conveyed to the suspension centrifuge through the suspension liquid pump, liquid and solid are rapidly separated under the action of centrifugal force, the liquid after liquid and solid separation is conveyed to the chlorination furnace cooling conduit through the liquid pump for spraying, and the liquid is gasified, the chlorination furnace cooling conduit is a U-shaped pipeline for enabling titanium tetrachloride mixed gas at the top of the chlorination furnace to enter a cyclone separator, the liquid is gasified and enters the cyclone separator, the titanium tetrachloride mixed gas in the cooling conduit is cooled, and the solid after liquid-solid separation is conveyed to a slag discharge groove of the chlorination furnace for neutralization treatment.

A process for recovering titanium tetrachloride from a titanium tetrachloride suspension, the process comprising the steps of:

step 1, pumping a suspension of titanium tetrachloride subjected to vanadium removal by mineral oil to a spiral plate heat exchanger, wherein the suspension of titanium tetrachloride subjected to vanadium removal by mineral oil refers to mud discharged from the bottom of a vanadium removal reactor after vanadium removal by mineral oil, the temperature of the suspension discharged from the bottom of the vanadium removal reactor is controlled to be 120-130 ℃, and the outlet temperature of the spiral plate heat exchanger is controlled to be 56.5-100 ℃;

step 2, enabling the vanadium-removing suspension subjected to cooling by the spiral plate heat exchanger to enter a buffer tank, wherein a tail gas discharge device is arranged at the top of the buffer tank, the suspension condensed by the spiral plate heat exchanger is the suspension discharged from the bottom of the vanadium-removing reactor after titanium tetrachloride is subjected to vanadium removal by mineral oil, the temperature of the suspension in the buffer tank is 56.5-100 ℃, and the gaseous silicon tetrachloride is discharged to a tail gas treatment system through the tail gas device at the top of the buffer tank because the vanadium-removing suspension contains a small amount of silicon tetrachloride and the boiling point of the silicon tetrachloride is 56.5 ℃, and the silicon tetrachloride in the buffer tank is gaseous;

step 3, starting a suspension centrifuge to work, pumping the suspension in the buffer tank to the suspension centrifuge, and rapidly separating liquid and solid under the action of centrifugal force, wherein the suspension centrifuge is a device for performing liquid-solid separation on the suspension through centrifugal force, and the suspension centrifuge allows the medium temperature to be-10-100 ℃;

step 4, pumping the liquid after liquid-solid separation to a chlorination furnace cooling conduit in a chlorination section for spraying, so that the liquid is gasified and enters a cyclone separator, wherein the chlorination furnace cooling conduit refers to a U-shaped pipeline through which titanium tetrachloride mixed gas at the top of the chlorination furnace enters the cyclone separator, the liquid is gasified and enters the cyclone separator, and meanwhile, the titanium tetrachloride mixed gas in the cooling conduit is cooled;

and 5, conveying the solid after liquid-solid separation to a slag discharging groove of the chlorination furnace for neutralization treatment.

The invention has the beneficial effects that:

(1) according to the method, the titanium tetrachloride in the vanadium-removing suspension is recovered by utilizing the cooling guide pipe of the chlorination furnace, so that on one hand, the process flow of ore pulp evaporation in the traditional process can be reduced, and the extra heating power consumption and processing time required in the ore pulp evaporation are saved; on the other hand, the problems of a large amount of titanium tetrachloride smoke, severe environment, environmental protection pressure and the like in the traditional process during ore pulp evaporation and slag discharge can be solved. The invention utilizes the suspension centrifuge to rapidly realize liquid-solid separation of the suspension under the action of centrifugal force, and then gasifies the liquid into a chlorination system through the cooling conduit of the chlorination furnace, thereby realizing the effective recovery of titanium tetrachloride. The suspension centrifugal pump has the advantages of high automation degree, capability of realizing continuous feeding and continuous discharging, low energy consumption, light working load, compact structure, small occupied area and convenient installation and maintenance. The method of the invention not only saves energy, but also cools the cooling conduit by the recovered titanium tetrachloride liquid, thereby reducing energy consumption.

(2) According to the invention, a reasonable operation mode is designed according to different feeding concentrations, and the rotating speed of the rotary drum is adjusted in real time by adopting a fuzzy control method according to the change of the moisture content of the discharged slag, so that the differential rotating speed is changed, and the optimal separation effect is achieved;

when the centrifuge works, the rotary drum and the spiral material conveyer rotate in the same direction at a high speed, but the rotation speed difference exists between the rotation speed of the spiral material conveyer and the rotation speed of the rotary drum, the rotation speed of the rotary drum and the differential speed between the rotary drum and the spiral material conveyer determine the indexes of material separation effect, yield and the like, and the indexes are important variable parameter fields of the centrifuge; the concentration of the suspension of the same material may change at different moments, that is, the centrifuge is required to correspondingly adjust the rotating speed difference between the rotary drum and the spiral material conveyor according to the data change of the material, so as to achieve the optimal separation effect;

(3) the suspension centrifuge of the present invention has the following advantages:

the adaptability is good: various special requirements of materials and processes on the centrifuge are fully considered in the process, and the optimization design of the main components in the aspects of specificity and adjustability is implemented;

the automation degree is high: the working procedures of feeding, separating, discharging and the like of the centrifuge during operation are continuously and automatically carried out under the high-speed operation. The automatic control of the centrifugal separation and centrifugal washing processes is realized by adopting a programmable controller;

the operation stability is good: the differential used by the centrifuge is a cycloidal gear differential or a planet gear differential, and has the characteristics of large torque, wide adjusting range and the like;

the manufacturability is strong: the centrifugal machine is controlled by a double-motor double-frequency conversion energy feedback differential rotation speed system, the differential rotation speed is flexibly and steplessly regulated, and the differential rotation speed is regulated at any time according to the change of materials;

the operating environment is good: the centrifuge separates the materials under the completely closed condition, thereby ensuring the operation site to be clean and pollution-free, keeping the production environment clean and sanitary, and realizing the civilized production;

the safety protection device is complete and reliable: the centrifugal machine is provided with multiple protections such as torque protection, power control and the like, so that damage to the machine caused by sudden faults can be effectively eliminated or reduced;

the appearance is beautiful: the machine seat of the machine is formed by welding high-quality carbon steel, and the surface of the machine seat is smooth and flat after being treated by a special process. Light, elegant and beautiful, and gives people an integral aesthetic feeling.

Drawings

FIG. 1 is a block diagram of a suspension centrifuge of the present invention;

FIG. 2 is a flow diagram of a process for recovering titanium tetrachloride according to the present invention;

wherein, a feed pipe; 2-main motor pulley; 3-main bearing oil injection hole; 4-a first spiral bearing; 5-helical blades; 6-rotating the drum; 7-a spiral bearing II; 8, a first main bearing; 9-main bearing oil injection hole; 10-auxiliary motor pulley; 11-a second main bearing; 12-a solid outlet; 13-a discharge hole; 14-liquid phase discharge port; 15-liquid baffle; 16-differential.

Detailed Description

The invention is further described with reference to the following figures and examples.

Embodiments of the present invention are illustrated with reference to fig. 1-2.

A system for recovering titanium tetrachloride from titanium tetrachloride suspension comprises a vanadium removal reactor, a suspension liquid pump, a spiral plate heat exchanger, a buffer tank, a tail gas exhaust device, a suspension centrifuge, a chlorination furnace cooling conduit, a liquid pump, a cyclone separator and a chlorination furnace slag discharge groove, wherein after mineral oil vanadium removal is carried out on titanium tetrachloride through the vanadium removal reactor, the titanium tetrachloride is conveyed to the spiral plate heat exchanger through the suspension liquid pump, vanadium removal suspension liquid cooled through the spiral plate heat exchanger enters the buffer tank, the tail gas exhaust device is arranged at the top of the buffer tank, gaseous silicon tetrachloride in the buffer tank is discharged to a tail gas treatment system through the tail gas device, the suspension liquid in the buffer tank is conveyed to the suspension centrifuge through the suspension liquid pump, liquid and solid are rapidly separated under the action of centrifugal force, the liquid after liquid and solid separation is conveyed to the chlorination furnace cooling conduit through the liquid pump for spraying, and the liquid is gasified, the chlorination furnace cooling conduit is a U-shaped pipeline for enabling titanium tetrachloride mixed gas at the top of the chlorination furnace to enter a cyclone separator, the liquid is gasified and enters the cyclone separator, the titanium tetrachloride mixed gas in the cooling conduit is cooled, and the solid after liquid-solid separation is conveyed to a slag discharge groove of the chlorination furnace for neutralization treatment.

Wherein, the suspension centrifuge comprises a main motor, an auxiliary motor, a feeding pipe, a main motor belt pulley, a main bearing oil injection hole, a first spiral bearing, a spiral blade, a rotary drum, a second spiral bearing, a first main bearing, a main bearing oil injection hole, an auxiliary motor belt pulley, a second main bearing, a solid discharge port, a liquid phase discharge port, a liquid baffle plate, a differential mechanism, a clutch, a motor starting device, an alarm device, an adjusting control device and a display device,

the device comprises an alarm device, an adjusting and controlling device, a display device, a fuzzy controller, a frequency converter and a turbidimeter, wherein the alarm device is used for bearing temperature alarm and overload alarm, the adjusting and controlling device is used for adjusting the rotating speed of the rotary drum, the rotating speed of the spiral blade and the differential speed between the rotary drum and the spiral blade according to the data change of suspension, the display device is used for displaying the running condition, the rotating speed, the temperature, the current, the alarm and the rotating voltage of the spiral blade, the adjusting and controlling device comprises the fuzzy controller, the frequency converter and the turbidimeter, the fuzzy controller is formed by a PLC (programmable logic controller), the fuzzy controller is used for generating the fuzzy;

the suspension enters the rotary drum 6 from the discharge port 13 through the feed pipe 1, the rotary drum 6 deposits solid-phase particles with large specific gravity on the inner wall of the rotary drum under the action of centrifugal force generated by high-speed rotation of a differential mechanism, the solid-phase particles deposited on the inner wall of the rotary drum are continuously scraped off and pushed out of a solid-phase discharge port 12 by the helical blade 5 which moves relative to the rotary drum, separated clear liquid overflows out of the rotary drum through a liquid-phase discharge port 14 of a liquid-layer adjusting plate, differential rotation between the helical blade and the rotary drum is realized through the differential mechanism 16, and the size of the differential rotation is controlled by an auxiliary motor, so that the centrifuge continuously;

the first main bearing and the second main bearing are connected between the shell and the rotary drum, and the first spiral bearing and the second spiral bearing are connected between the spiral blades and the rotary drum, so that the spiral blades and the rotary drum can rotate.

A process for recovering titanium tetrachloride from a titanium tetrachloride suspension, the process comprising the steps of:

step 1, pumping a suspension of titanium tetrachloride subjected to vanadium removal by mineral oil to a spiral plate heat exchanger, wherein the suspension of titanium tetrachloride subjected to vanadium removal by mineral oil refers to mud discharged from the bottom of a vanadium removal reactor after vanadium removal by mineral oil, the temperature of the suspension discharged from the bottom of the vanadium removal reactor is controlled to be 120-130 ℃, and the outlet temperature of the spiral plate heat exchanger is controlled to be 56.5-100 ℃;

step 2, enabling the vanadium-removing suspension subjected to cooling by the spiral plate heat exchanger to enter a buffer tank, wherein a tail gas discharge device is arranged at the top of the buffer tank, the suspension condensed by the spiral plate heat exchanger is the suspension discharged from the bottom of the vanadium-removing reactor after titanium tetrachloride is subjected to vanadium removal by mineral oil, the temperature of the suspension in the buffer tank is 56.5-100 ℃, and the gaseous silicon tetrachloride is discharged to a tail gas treatment system through the tail gas device at the top of the buffer tank because the vanadium-removing suspension contains a small amount of silicon tetrachloride and the boiling point of the silicon tetrachloride is 56.5 ℃, and the silicon tetrachloride in the buffer tank is gaseous;

step 3, starting a suspension centrifuge to work, pumping the suspension in the buffer tank to the suspension centrifuge, and rapidly separating liquid and solid under the action of centrifugal force, wherein the suspension centrifuge is a device for performing liquid-solid separation on the suspension through centrifugal force, and the suspension centrifuge allows the medium temperature to be-10-100 ℃;

step 4, pumping the liquid after liquid-solid separation to a chlorination furnace cooling conduit in a chlorination section for spraying, so that the liquid is gasified and enters a cyclone separator, wherein the chlorination furnace cooling conduit refers to a U-shaped pipeline through which titanium tetrachloride mixed gas at the top of the chlorination furnace enters the cyclone separator, the liquid is gasified and enters the cyclone separator, and meanwhile, the titanium tetrachloride mixed gas in the cooling conduit is cooled;

and 5, conveying the solid after liquid-solid separation to a slag discharging groove of the chlorination furnace for neutralization treatment.

When the suspension centrifuge works, the load of the rotary drum changes due to the uneven density of the suspension entering the rotary drum, so that the suspension centrifuge still can keep better running characteristics under the working condition of load variation, the rotating speed of the suspension pump, the rotary drum and the helical blades is adjustable,

the rotary drum and the helical blades of the suspension centrifuge are driven by adopting a frequency converter speed regulation mode, so that stepless speed regulation of the rotary drum and the helical blades is realized, and the suspension centrifuge requires higher rotating speed of the rotary drum during operation, has larger load and needs to work for a long time; in order to ensure long-term reliable operation of the equipment, the temperature of the drum support bearing is automatically monitored.

In the step 3, the suspension centrifuge specifically comprises the following working steps:

step 3.1, collecting analog quantities of monitoring points from the site, wherein the analog quantities comprise motor temperature, bearing temperature, rotary drum torque and slag discharge moisture content;

step 3.2, judging the ready condition of the suspension centrifuge according to the analog quantity in the step 3.1, determining whether the suspension centrifuge can be started, comparing the collected field motor temperature and bearing temperature with a set alarm value and a stop value, alarming or continuing to stop if the collected field motor temperature and bearing temperature exceed the set alarm value and the stop value, otherwise, entering the step 3.3;

3.3, if the analog quantity meets the requirement, all the suspension centrifuges are in a ready state, and the suspension centrifuges are started;

3.4, starting the auxiliary motor to drive an auxiliary motor belt pulley, wherein the spiral blade runs at a low speed to remove residual substances possibly left in the last running, so that the situation of large starting vibration caused by uneven distribution of the residues possibly generated during the starting of the rotary drum is avoided, after the residual substances are removed, starting the main motor to drive the rotary drum to start running, and selecting a working mode after the stable rotating speed is reached, wherein the working mode is manual, automatic and stopping;

step 3.5, when the suspension centrifuge is closed, reducing the speed of the rotary drum, then continuously discharging the residual substances out of the machine by the spiral blade until the operator considers the satisfaction, separately and independently driving the rotary drum and the spiral blade, independently starting the spiral blade under the condition that the suspension centrifuge is blocked, and discharging the residual substances staying in the suspension centrifuge under the condition of low speed;

the separate independent driving of the drum and the helical blades simplifies the maintenance and repair process.

Wherein, in the step 3.4,

during manual operation, an operator sets the rotating speed of the rotary drum and the rotating speed difference of the differential, and starts the suspension pump, so that manual operation is realized;

during automatic operation, measuring whether the concentration of fed materials is less than a given concentration, and adjusting and controlling the device to judge whether differential operation or zero differential operation is selected; when the feeding concentration is detected to be greater than the given concentration, the fuzzy controller of the adjusting control device performs differential operation based on a fuzzy control method;

when the operation is stopped, the suspension pump is closed, the main motor is closed, and the auxiliary motor is closed;

the zero differential speed operation in the automatic operation of the step 3.4 comprises the following specific steps:

step 3.4.A1, when the suspension centrifuge operates at zero differential speed, the main motor increases the speed, the rotating drum increases the rotating speed to the preset rotating speed, the main motor drives the differential gear shell, the differential integrally rotates under the action of the clutch, the gear shell in the differential does not move relative to the input shaft, and the rotating drum and the helical blade rotate in the same direction at the same speed;

step 3.4.A2, turning off the auxiliary motor;

step 3.4.A3, opening a suspension pump;

step 3.4.A4, judging whether the torque of the rotary drum is larger than the preset upper limit torque, if so, entering step 3.4.A5, otherwise, returning to step 3.4. A3;

step 3.4.A5, in the separation process, feeding from the feeding pipe and discharging clear liquid from the liquid phase discharge port simultaneously and continuously, and when the sediment layer settled in the rotary drum is accumulated to a certain thickness, closing the suspension pump and stopping feeding and discharging liquid;

step 3.4.A6, starting the auxiliary motor under the full-speed operation condition to drive the input shaft of the differential mechanism, and enabling the helical blade to rotate at a preset speed;

step 3.4.A7, discharging the sediment from a solid discharge port of the rotary drum;

and 3.4.A8, judging whether the torque of the rotary drum is smaller than the preset lower limit torque, if so, returning to the step 3.4.A2, and otherwise, returning to the step 3.4. A7.

The fuzzy control method in the automatic operation of step 3.4 specifically comprises the following steps:

the physical parameters of the suspension are changed along with the time, wherein the concentration is a dynamic parameter, and under a fixed separation parameter, the separation effect performance is changed by the change of the concentration; meanwhile, the moisture content of the suspension can fluctuate due to the change of the input flow of the suspension, when the feed concentration is greater than the given concentration, the suspension centrifuge performs differential operation, the rotating speed difference is adjusted in real time by using a fuzzy control method according to the change of the moisture content of the discharged slag, and the control object is the moisture content of the settled slag; the executive component is a main motor driving the rotary drum; the measuring element is a turbidimeter, measures the moisture content of the separated sediment, converts the moisture content into a voltage signal, and then amplifies and filters the voltage signal; the fuzzy controller fuzzifies a signal sampled by the turbidimeter, fuzzy operation is carried out on the fuzzy quantity to obtain fuzzy output quantity, then the output quantity is defuzzified to obtain accurate quantity, and the frequency converter controls the main motor to output power of the execution element;

the fuzzy controller stores the established offline fuzzy control lookup table in a PLC memory according to a certain rule, and when the fuzzy controller performs real-time control, the precise quantity obtained after sampling is subjected to level quantization to obtain corresponding fuzzification discourse field elements, a quantized value of the output control quantity is obtained through table lookup, and the quantized value is multiplied by a scale factor to obtain the final precise control quantity.

The method comprises the following specific steps:

step 3.4.B1, determining the structure of the fuzzy controller;

step 3.4.B2, determining language variables;

the method specifically comprises the following steps:

step 3.4.B2.1, setting sediment given humidity as c_dIf the actual sediment humidity is measured to be c, the sediment humidity error is e,

e＝c_d-c，

the linguistic variable is E, the domain of discourse is X { -3, -2, -1,0, +1, +2, +3}, and the fuzzy subset on the domain of discourse is

The corresponding linguistic values are:

{ negative large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), positive large (PB) }, respectively, which respectively represent the currently measured actual humidity c of the sediment relative to the given humidity c of the sediment_dIs extremely high, very high, just in time, very low;

and 3.4.B2.2, wherein the variable quantity of the sampling values before and after the sediment humidity error is ec: ec is c₂-c₁，

The linguistic variable is EC, the domain is Y { -2, -1,0, +1, +2}, and the fuzzy subset on the domain is

The corresponding linguistic values are:

{ negative large (NB), Negative Small (NS), Zero (ZO), Positive Small (PS), positive large (PB) } indicates the current sludge wetting, respectivelyChange in degree c₂-c₁The rapid decrease, invariance, increase and rapid increase;

step 3.4.B2.3, output the controlled variable U, the linguistic variable is U, the domain Z { -3, -2, -1,0, +1, +2, +3}, the fuzzy subset on the domain is

The corresponding linguistic values are:

{ negative large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM) and positive large (PB) }, which respectively represent the actions of the control execution mechanism, namely large reduction amount of the rotating drum rotating speed, small reduction amount of the rotating drum rotating speed, unchanged rotating drum rotating speed, small acceleration amount of the rotating drum rotating speed, and large acceleration amount of the rotating drum rotating speed;

step 3.4.B3, establishing a linguistic variable assigned value table as shown below;

TABLE 1 linguistic variable E assignment Table

The table is for different linguistic variables E and fuzzy subsets

The corresponding output value is set to be the value,

table 2 linguistic variables EC assignment table

The table is based on different linguistic variables EC and fuzzy subsets

In response to the output value,

TABLE 3 linguistic variable U assignment Table

The table is for different linguistic variables U and fuzzy subsetsIn response to the output value,

step 3.4.B4, accumulating according to expert knowledge and experience of skilled operators, giving out a fuzzy control rule, and when the error is large or large, selecting the change of the control quantity to quickly reduce the error as much as possible and eliminate the error; when the error is small, the stability of the system is considered besides the error is eliminated, unnecessary overshoot and even oscillation of the system are prevented, and a fuzzy rule table is established according to a fuzzy control rule, as follows:

TABLE 4 fuzzy rule Table

The table is the fuzzy value of the linguistic variable U under the conditions of different linguistic variables E and EC;

step 3.4.B5, synthesizing and reasoning all possible situations one by one according to the quantization levels of the linguistic variable E and the EC discourse domain, calculating all corresponding output values by adopting a weighted average method fuzzy solving method, combining the output values with tables 1-4, and synthesizing a fuzzy control lookup table as follows:

TABLE 5 fuzzy control look-up table

The table is a control value of the output control quantity u under the conditions of different linguistic variables E and EC; and 3.4.B6, outputting the control quantity u through a scale conversion output frequency converter, and further controlling the rotating speed of the main motor, thereby realizing fuzzy control.

The above-described embodiment merely represents one embodiment of the present invention, but is not to be construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.