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System for measuring particle size distribution of particles in slurry loop reactor

A loop reactor and particle size distribution technology, which is applied in particle and sedimentation analysis, measuring devices, particle size analysis, etc., can solve problems such as indeterminate collision position and energy, unstable response coefficient, and reduced signal authenticity, so as to avoid Effects of signal distortion, improved measurement accuracy, and improved test progress

Pending Publication Date: 2020-07-31
SHANGHAI RES INST OF CHEM IND +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are still the following problems in the application of acoustic emission technology to the loop reactor: 1. Since the collision of particles on the reactor wall is random, the collision position and energy are uncertain, and the factors that affect the characteristic frequency of the acoustic signal generated by it include particles, devices, etc. Wall material, gas velocity, etc., there are still large errors in practical applications
2. At present, most of the acoustic emission research uses pseudo-broadband acoustic emission sensors or broadband acoustic emission sensors. These two types of sensors have a wide response range, but they have disadvantages such as low sensitivity, unstable response coefficient, and reduced signal authenticity.

Method used

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  • System for measuring particle size distribution of particles in slurry loop reactor
  • System for measuring particle size distribution of particles in slurry loop reactor

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Embodiment 1

[0030] Such as figure 1 As shown, this embodiment provides a particle size distribution measurement system in a slurry loop reactor, including an acoustic wave receiving module 1 , a signal amplifying module 2 , a signal collecting module 3 and a signal processing module 4 connected in sequence. The acoustic wave receiving module 1 is connected to the loop reactor 5 . Wherein, the acoustic wave receiving module 1 includes a plurality of narrow-band acoustic emission sensors 11 with different response frequency bands, and the response frequency bands of all the narrow-band acoustic emission sensors 11 are continuously distributed. The gain range of the signal amplification module 2 is 1-100. The signal acquisition frequency range of the signal acquisition device 3 is 10 Hz-5 MHz. Executing the program in the signal processing module 4 realizes the following steps:

[0031] Step S1. Obtain the acoustic emission signal received by each narrowband acoustic emission sensor, and ...

Embodiment 2

[0042] The difference from Embodiment 1 is that the narrow-band acoustic emission sensors are located at 40% of the horizontal pipe section at the lower end of the loop reactor, and seven narrow-band acoustic emission sensors are evenly arranged along the fluid flow direction and on the same straight line. Finally, the measurement error of particle size distribution in the slurry loop reactor is about 5.3%.

Embodiment 3

[0044] The difference from the first embodiment is that two narrow-band acoustic emission sensors are uniformly arranged along the circumferential direction of the cross-section of the loop reactor. The narrowband acoustic emission sensor responses are 100-400kHz and 400-700kHz respectively. After the received acoustic emission time domain information is obtained by fast Fourier transform to obtain the frequency domain information, the db2 wavelet function is used to decompose the two sections of acoustic emission signals in three scales respectively, and the distribution of wavelet energy fractions in each scale Characterize the spectral structure of a signal. The corresponding frequency ranges after wavelet decomposition are 225~400kHz, 162.5~225kHz, 100~162.5kHz, 550~700kHz, 475~550kHz, 400~475kHz. Measurement results The particle size distribution measurement error is about 4.7%.

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Abstract

The invention relates to a system for measuring particle size distribution of particles in a slurry loop reactor. The system comprises a sound wave receiving module, a signal amplification module, a signal acquisition module and a signal processing module which are connected in sequence, the sound wave receiving module is connected with a loop reactor, the sound wave receiving module comprises a plurality of narrow-band acoustic emission sensors with different response frequency bands, and the response frequency bands of all the narrow-band acoustic emission sensors are continuously distributed. Compared with systems in the prior art, the system of the invention has the following advantages: the sensitivity to each frequency band during acoustic emission signal acquisition can be effectively improved, signal distortion is avoided, and the measurement precision of particle size distribution of particles in the slurry loop reactor is improved.

Description

technical field [0001] The invention relates to the testing field of a slurry loop reactor, in particular to a measurement system for particle size distribution in a slurry loop reactor. Background technique [0002] A slurry process refers to a polymerization reaction in which neither the catalyst nor the polymer formed is soluble in the monomer and solvent. Since the catalyst is in the form of a dispersion in the diluent, the formed polymer is also precipitated in the form of a fine dispersion, and the entire polymerization system is in the form of a slurry, so it is called slurry polymerization. The slurry process mainly includes the stirred tank process and the loop pipe process. In the loop process, the loop reactor is used, with isobutane as the diluent, the refined ethylene is mixed with the comonomer and reacted under the action of the catalyst, and the formed slurry is circulated under the action of the pump. Polyethylene products with different density characteri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/02
CPCG01N15/02
Inventor 阳永荣叶晓峰骆广海黄正梁李建龙肖明威叶纯麟
Owner SHANGHAI RES INST OF CHEM IND