CN105334134A - Method for determining residence time of titanium concentrate in high-temperature fluidization reactor - Google Patents

Abstract

The invention belongs to the field of chemical engineering, and in particular relates to a method for measuring the residence time of titanium concentrate in a high-temperature fluidized reactor. The technical problem to be solved by the present invention is that ordinary tracers cannot play a role at high temperature, which makes it difficult to measure the residence time of materials in the reactor. The solution of the present invention to solve the above-mentioned technical problems is to provide a method for measuring the residence time of titanium concentrate in a high-temperature fluidized reactor, comprising the following steps: a, in the process of adding titanium concentrate to the high-temperature fluidized reactor, Add the tracer to the titanium concentrate at a uniform speed; b. After the reaction of the titanium concentrate is completed, use a magnetic separator to separate and recover the tracer and weigh it in real time; c. According to the quality and time of the real-time weighing of the tracer Corresponding relationship, calculate the average residence time of titanium concentrate. The method provided by the invention has the advantages of simple operation, good convenience and reproducibility, accurate measurement, good representativeness, less equipment investment and low operation cost, and is very suitable for large-scale industrial application.

Description

Determination method of residence time of titanium concentrate in high temperature fluidized reactor

technical field

The invention belongs to the field of chemical engineering, and in particular relates to a method for measuring the residence time of titanium concentrate in a high-temperature fluidized reactor.

Background technique

Fluidized bed reactors have been widely used in chemical industry, energy, light industry, metallurgy, materials, medicine, Food and environmental protection and many other fields. However, in a fluidized bed reactor, the fluid and the particles interact with each other, and the displacement of each particle will inevitably cause a change in the fluid velocity at that point, which in turn affects the displacement of the particles. Different fluid velocities lead to particle movement patterns and trajectories. Therefore, the movement of particles is not simply caused by fluid turbulence in the uniform dispersed flow field, and the trajectory of particles is complex, with large changes and poor reproducibility. For such a complex system, it is difficult to determine the operating parameters and research is difficult, so the operating parameters of the fluidized reactor basically use the average concept instead of individual research.

Residence time is the time it takes for a material to pass through continuously operating processing equipment from the time it enters to the time it leaves. Each particle in the material has a corresponding residence time, that is, there is a residence time distribution (RTD). RTD is a basic parameter to characterize the performance of chemical equipment. It mainly characterizes the flow of materials in the equipment and the mixing related to flow, chemical reaction kinetics, heat and mass transfer and other issues.

Due to its high impurity content and good acid solubility, Panzhihua titanium concentrate must be subjected to high-temperature strong oxidation and reduction pretreatment in the preparation of artificial rutile to change the crystal structure of its titanium-containing phase, effectively restricting the occurrence of hydrochloric acid in the leaching process. Reaction, dissolution and hydrolysis lead to particle refinement, while improving the reactivity of impurity elements, improving the removal rate of impurity elements, and improving the quality of artificial rutile products. For the high-temperature heat treatment process of titanium concentrate, the RTD of titanium concentrate in the fluidized reactor is closely related to the crystal structure transformation of the process, which in turn affects the quality of the product.

Patent CN101839859B discloses a material residence time distribution test device. The light beam emitted by the excitation light source is incident on the material to be tested through a half-transparent mirror, and the tracer in the material to be tested emits fluorescence after being excited. After the semi-transparent half mirror, it is transmitted to the fluorescence detector, and analyzed by the signal processing unit to calculate the residence time distribution of the material. The main equipment mainly includes a light tube, an optical window, a fluorescence detector, a signal processing unit, an excitation light source, a half mirror and a light source power supply unit, etc. Main advantages: The excitation beam and fluorescence do not need to be coupled with the optical fiber during the exit process, which can greatly reduce the coupling loss and cost, and the optical path is compactly arranged, and the test device is small in size. The material residence time distribution test device is only electrically connected to the signal processing unit and the light source power supply unit, which is extremely convenient to use and can conveniently isolate the high temperature and high pressure environment of the tested material. Disadvantages: complex structure, low stability, easily affected by the high temperature environment of the reactor, real-time online monitoring, complex trajectory of the tracer in the reactor, which requires powerful calculation and professional software processing, and the cost of industrial application is high.

In patent 200410025407.6 and patent 200710179497.8, the concentration determination of tracers is mainly based on the principles of radioactivity, ultrasonic reflection, optical reflection, conductivity, magnetism, and near-infrared absorption, using MnO ₂ , La ₂ O ₃ , fillers, carbon black, TiO _2. Tracers with different properties such as KNO ₃ , NaCl, iron powder, colored dyes, etc.

Patent CN201010510265.8 discloses a method for measuring the residence time distribution of tobacco materials in processing equipment, including the following steps: a. Select a common component in tobacco materials as a tracer to meet the accuracy detection requirements; b. 1. Add the tracer to the equipment inlet material flow of stable work with a certain tracer method, and simultaneously detect the response value of its concentration changing with time at the outlet with a certain time interval to obtain the residence time distribution (RTD) function; c, the function The model equation of this function can be obtained by non-linear fitting with a suitable flow model, and the average residence time of the material and the mixing degree in the axial direction of the equipment can be obtained. The main advantages of this invention are: 1. Use a common component in the tobacco material as a tracer to measure the RTD of the tobacco material in the processing equipment, and the test time is short, the range of influence is small, and the detection method has high accuracy. The quality impact is small and will not pose a threat to the safety of consumers; 2. The method can predict, optimize and control the quality of WIP. The disadvantage is that it is highly specialized and has a narrow scope of application.

The high-temperature and strong redox pretreatment of Panzhihua titanium concentrate aims to change the titanium-containing phase structure in the titanium concentrate, so the average residence time of the titanium concentrate in the reactor directly affects the conversion rate of the phase structure. At the same time, the reactor maintains a high temperature of about 1000°C, and ordinary tracers cannot play a role, which makes it difficult to measure the residence time of materials in the reactor, and the existing test methods basically cannot be applied to this system.

Contents of the invention

The technical problem to be solved by the present invention is that ordinary tracers cannot play a role, which makes it difficult to measure the residence time of materials in the reactor.

The solution of the present invention to solve the above-mentioned technical problems is to provide a method for measuring the residence time of titanium concentrate in a high-temperature fluidized reactor, comprising the following steps:

a. When the titanium concentrate is stably added to the high-temperature fluidized reactor, the tracer is added to the titanium concentrate at a uniform speed;

b. After the reaction of the titanium concentrate in the high-temperature fluidized reactor is completed, the tracer is sorted and recovered by a magnetic separator at the discharge port of the high-temperature fluidized reactor and weighed in real time. When the tracer is recovered When the rate reaches more than 95%, the recycling is completed;

c. Calculate the average residence time of the titanium concentrate according to the corresponding relationship between the real-time weighing quality of the tracer and the time.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the tracer described in step a is iron concentrate.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the total amount of tracer added in step a is 5% to 15% of the mass of titanium concentrate.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the adding time of the tracer in step a is 20-40 minutes.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the formula for calculating the average residence time of titanium concentrate described in step c is: t _i is the time of weighing during the recovery process, and A _i is the quality of iron ore concentrate obtained by weighing t _i during the recovery process.

The method for measuring the residence time of titanium concentrate in a high-temperature fluidized reactor provided by the present invention uses iron concentrate as a tracer to test the average residence time of reaction materials, which has high accuracy and will not damage the continuous stability of system operation. It will not affect the operating parameters of the system. At the same time, since the properties of the tracer are basically the same as the elements contained in the reactant, even a trace amount of tracer entering the system will not cause pollution to the product. The method provided by the invention is simple and convenient to operate, has good reproducibility, is accurate in measurement, has good representativeness, has less equipment investment and low operating cost, and is very suitable for large-scale industrial application.

detailed description

The measuring method of the titanium concentrate residence time in the high-temperature fluidized reactor comprises the following steps:

a. During the process of adding the titanium concentrate to the high-temperature fluidized reactor, the tracer is added to the titanium concentrate at a uniform speed;

b. After the reaction of the titanium concentrate in the high-temperature fluidized reactor is completed, the tracer is sorted and recovered by a magnetic separator at the discharge port of the high-temperature fluidized reactor and weighed in real time. When the tracer is recovered When the rate reaches more than 95%, the recycling is completed;

c. Calculate the average residence time of the titanium concentrate according to the corresponding relationship between the real-time weighing quality of the tracer and the time.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the tracer described in step a is iron concentrate.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the total amount of tracer added in step a is 5% to 15% of the mass of titanium concentrate.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the adding time of the tracer in step a is 20-40 minutes.

In the method for measuring the residence time of titanium concentrate in the above-mentioned high-temperature fluidized reactor, the formula for calculating the average residence time of titanium concentrate described in step c is: t _i is the time of weighing during the recovery process, and A _i is the quality of iron ore concentrate obtained by weighing t _i during the recovery process. Since the travel of the tracer and the titanium concentrate is exactly the same, the average residence time of the titanium concentrate can be calculated according to the corresponding relationship between the real-time weighing quality of the tracer and the time.

The titanium concentrate is pretreated by high temperature and strong oxidation, which changes the crystal structure of the titanium concentrate, and effectively prevents the reaction with hydrochloric acid during the leaching process, resulting in the refinement of artificial rutile products. At the same time, through high-temperature strong oxidation treatment, the reactivity of impurity elements in titanium concentrate is enhanced, the removal rate of impurity elements is improved, and high-quality artificial rutile products are obtained. The gas-solid fluidized reaction mode is used for pretreatment, and the gas-solid fluidized bed (a high-temperature fluidized reactor) is selected. The reaction temperature is 900-1100°C. The residence time of titanium concentrate in the fluidized bed directly affects the crystal form. Structural conversion rate and impurity element removal rate affect the quality of artificial rutile products and are one of the main control indicators in the pretreatment process. By analyzing the properties of titanium concentrate and iron concentrate, their main elements are basically the same. Even if the impurity elements in iron concentrate are mixed into titanium concentrate, the impurity elements can be processed through the post-process, and will not affect the quality of artificial rutile products. influences. However, the Fe and Ti contents of titanium concentrate and iron concentrate are quite different, and the ore phase structure and crystal structure are different. Therefore, the specific magnetization system of the two minerals is quite different. After the high-temperature fluidized reactor, magnetic separation equipment According to the difference in the specific magnetic susceptibility coefficients of the two minerals after high-temperature treatment, the iron concentrate is sorted out by adjusting the magnetic field strength. Therefore, the present invention selects the iron concentrate as a tracer for high-temperature roasting of the titanium concentrate.

Example 1

a. During the process of adding 1500kg/h of titanium concentrate to the high-temperature fluidized reactor, 60kg of iron ore concentrate is added at a constant speed for 30 minutes, and the completion of feeding is used as the starting point for timing.

b. After the reaction of the titanium concentrate in the high-temperature fluidized reactor is completed, use a magnetic separator to sort and recover the tracer at the discharge port of the high-temperature fluidized reactor and weigh it once every 1 minute. The tracer recovery rate reaches more than 95% until there is basically no iron concentrate in the titanium concentrate.

c. The quality A _i and time t _i of the iron ore concentrate obtained during the recovery process are shown in Table 1.

Obtain iron ore concentrate quality and time in the recovery process of table 1

By calculation, the iron concentrate yield is 98.98%, through the formula: The average residence time of titanium concentrate in the reactor was calculated to be 88.5min.

The method provided by the invention is simple and convenient in operation, good in reproducibility and accurate in determination.

Claims (5)

1. The assay method of titanium concentrate residence time in the high-temperature fluidized reactor comprises the following steps: a. During the process of adding the titanium concentrate to the high-temperature fluidized reactor, the tracer is added to the titanium concentrate at a uniform speed; b. After the reaction of the titanium concentrate in the high-temperature fluidized reactor is completed, the tracer is sorted and recovered by a magnetic separator at the discharge port of the high-temperature fluidized reactor and weighed in real time. When the tracer is recovered When the rate reaches more than 95%, the recycling is completed; c. Calculate the average residence time of the titanium concentrate according to the corresponding relationship between the real-time weighing quality of the tracer and the time. 2. the assay method of titanium concentrate residence time in the high-temperature fluidized reactor according to claim 1 is characterized in that: the tracer described in step a is iron concentrate. 3. the assay method of titanium concentrate residence time in the high-temperature fluidized reactor according to claim 1, is characterized in that: the adding total amount of tracer described in step a is 5%～15% of titanium concentrate quality %. 4. The method for measuring the residence time of the titanium concentrate in the high-temperature fluidized reactor according to claim 1, characterized in that: the adding time of the tracer in step a is 20 to 40 minutes. 5. the assay method of titanium ore concentrate residence time in the high-temperature fluidized reactor according to claim 1, is characterized in that: the formula that calculates titanium concentrate ore average residence time described in step c is: t _i is the time of weighing during the recovery process, and A _i is the quality of iron ore concentrate obtained by weighing t _i during the recovery process.