Method for detecting dynamic material level in fluidized bed

A detection method and fluidized bed technology, applied in the direction of liquid level indicators for physical variable measurement, etc., can solve the problems of high price, complex measurement system, limited application range of temperature measurement method and capacitance method, etc., to achieve accurate results and improve The effect of fluidized bed production and product quality improvement

Active Publication Date: 2016-09-28
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the echo method uses advanced testing methods, the measurement system is complicated, the price is expensive, and the measurement accuracy needs to be further improved.
To sum up, although there are some detection methods for fluidized bed material level height, the various measurement methods are not satisfactory for practical application, especially the temperature measurement method and capacitance method are limited in scope of application.

Method used

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  • Method for detecting dynamic material level in fluidized bed
  • Method for detecting dynamic material level in fluidized bed
  • Method for detecting dynamic material level in fluidized bed

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Experiments were carried out using a plexiglass fluidized bed cold model experimental device, and the schematic diagram of the device is shown in figure 1 As shown, it is composed of a fluidization system and a detection system, 1 is a computer, 2 is a data acquisition card, 3 is a fan, 4 is a dryer, 5 is a flow meter, and 6 is an air inlet valve. The fluidized particles are LLDPE particles. The physical parameters of the particles are shown in Table 1. They belong to the Geldart B type particles. The initial fluidization velocity (u mf ) is 0.2m / s. The relative humidity of the fluidization gas is 8-15%, and the experiment is carried out at room temperature. Under the superficial gas velocity (u) involved in the experiment, the fluidized bed is always in a bubbling fluidized state. Table 2 shows the material weight and experimental gas velocity range of the particles.

[0027] Table 1 Some physical parameters of LLDPE particles

[0028]

[0029] Table 2 B type fl...

Embodiment 2

[0046] The fluidized bed in Example 1 is replaced by a plexiglass fluidized bed with a diameter of 420mm, and the material weight of the LLDPE particles is increased to 13.5g to ensure that the static bed height remains consistent with that of Example 1. The electrode arrangement is as Figure 7 As shown, using an annular induction electrode array matched with the fluidized bed, the wide width of the induction electrode is 40mm, the arrangement of the electrode array is consistent with that of Example 1, the sampling frequency is increased to 6000Hz, and the superficial gas velocity is increased to 0.7m / s.

[0047] Collect data for experiments:

[0048] 1) Sweep the plexiglass fluidized bed with dry air for 10 minutes, then add 13.5 kg of pre-dried LLDPE particles, and the static bed height is 265 mm.

[0049] 2) Fluidize the particles for 30 minutes at a certain superficial gas velocity to ensure that the particles are fully charged and saturated. At the same time, the el...

Embodiment 3

[0054] The experimental device and experimental method are the same as in Example 1. The fluidized particles are replaced by PP particles. The physical parameters of the particles are shown in Table 3. They belong to the Geldart D type particles. The initial fluidization velocity (u mf ) is 0.5m / s, and the material weight and experimental gas velocity range of the particles are shown in Table 4.

[0055] Table 3 Some physical parameters of PP particles

[0056]

[0057] Table 4 PP pellet weight and experimental gas velocity

[0058]

[0059] The signal acquisition method and data processing method are all the same as in Example 1, and the normalized probability density distribution of the relative velocity of the particle group at different positions is obtained as follows: Figure 9 .

[0060] Combined with the specific position of the electrode, it is speculated that at this gas velocity, the fluctuation range of the dynamic material level is 380-580mm, and the aver...

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Abstract

The invention discloses a method for detecting the dynamic material level in a fluidized bed. The method comprises steps as follows: 1) an inductive type electrostatic sensor array is used for continuously acquiring inductive electrostatic pressure signals in the gas-solid fluidized bed; 2) related speeds of particles are calculated by means of the inductive electrostatic pressure signals detected by upstream and downstream adjacent electrodes, and normalized probability density distribution at the related speeds is acquired; 3) normalized probability density distribution characteristics of the particles at related speeds detected by the electrodes in different axial positions are contrasted, and the dynamic material level fluctuation interval is obtained. The method has the characteristics of high precision, on-line property and noninvasive property, and equipment is simple in structure and wide in applicability.

Description

technical field [0001] The invention belongs to the technical field of gas-solid two-phase flow measurement, and in particular relates to a method for detecting the dynamic material level of a gas-solid fluidized bed based on correlation velocity measurement. Background technique [0002] The material level height of the gas-solid fluidized bed is one of the basic parameters of the fluidized bed. For example, in a fluidized bed reactor for olefin polymerization, the height of the material level directly affects the quality and output of polyolefin products. Timely and accurate detection of the height of the material level can not only maintain the stability of the fluidization quality of the fluidized bed, but also ensure The fluidized bed is operated at the optimum fluidization height to obtain high output. Similarly, in a coal-fired bubbling fluidized bed, the height of the fuel in the bed determines the degree of burnout and combustion efficiency of pulverized coal parti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01F23/22
CPCG01F23/22
Inventor 黄正梁王靖岱张擎娄浙栋杨遥董克增葛世轶阳永荣蒋斌波廖祖维孙婧元陆飞鹏范小强王浩同
Owner ZHEJIANG UNIV
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