A Multimodal Tomography System Based on ECT Sensors

Marashdeh, Qussai M.; Warsito, W.; Fan, Liang‐Shih; Teixeira, Fernando L.

doi:10.1109/jsen.2006.890149

Cited by 76 publications

(46 citation statements)

References 19 publications

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“…In Marashdeh et al (2007), the ECT system is not only used for measuring the permittivity from the measured capacitance, but also the power is considered, providing data for conductivity imaging. A dual sensitivity map for permittivity and for conductivity is created and used in an iterative LBP algorithm.…”

Section: Electric Capacitance Tomographymentioning

confidence: 99%

Measuring the Gas-Solids Distribution in Fluidized Beds -- A Review

Ommen¹,

Mudde²

2008

International Journal of Chemical Reactor Engineering

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In gas-solid fluidized beds, the distribution of the particles typically varies both in time and space. Since the gas-solids distribution and its variation have a strong influence on the performance of a fluidized bed for a given process, it is very important to accurately measure the gas-solids or voidage distribution. This paper reviews techniques for measuring the voidage distribution in gas-solid fluidized beds, with a focus on the developments during the last ten years. We will treat subsequently direct visualisation, tomography, optical probes, capacitance probes, and pressure measurements.Dense gas-solids flows are typically opaque to visible light. This makes optical techniques only of limited use in dense gas-solids flow. However, direct visualization can be useful for very dilute systems, pseudo 2-D beds, and the outer layer of dense, 3-D systems. Tomography is frequently used to obtain the voidage distribution in a horizontal cross-section of the bed. Electric capacitance tomography is fast, but its spatial resolution is limited and image reconstruction is still troublesome. Although some steps forward have been made, research is continuing at this point. For nuclear (X-ray and gamma-ray) tomography, the image reconstruction is much easier and the spatial resolution better, but its temporal resolution is typically much lower. Therefore, research efforts for nuclear tomography are mainly aimed at increasing the measurement frequency. Optical probes determine the voidage as a function of time in a small measurement volume, either by the degree of reflection or by the degree of transmission of a light bundle. Capacitance probes determine the voidage as a function of time in a small measurement volume by measuring the dielectric permittivity of the gas-solids suspension in the measurement volume. Both optical and capacitance probe techniques are reasonably well-developed; the current research effort spent at improving them seems * We would like to thank M.O. Coppens, J. Nijenhuis, R.W.S Bohlken, and M.A. Wormsbecker for useful suggestions during preparation of this manuscript. limited, especially for capacitance probes. Time-averaged pressure measurements are commonly used to determine the average bed density and bed height. By sampling the local pressure at a sufficiently high frequency (typically in the order of 200 Hz), much more information can be obtained about the fluidized bed hydrodynamics. However, obtaining quantitative voidage data from pressure fluctuations measurement remains a difficult task; in-bed pressure fluctuation (and acoustic) measurements are mostly used to determine changes in the voidage dynamics and distribution.

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Section: Electric Capacitance Tomographymentioning

confidence: 99%

Measuring the Gas-Solids Distribution in Fluidized Beds -- A Review

Ommen¹,

Mudde²

2008

International Journal of Chemical Reactor Engineering

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“…Marashdeh et al (2007) investigated the possibility to apply multimodal tomography (capacitance -impedance), using a typical ECT sensor. The aim of the research was the study of detection of the location of substances differing in permittivity and conductivity.…”

Section: Possibilities Of Temperature Distribution Analysis Using Ectmentioning

confidence: 99%

“…This is connected with the necessity to measure two parameters which can determine the sought distributions ' and " instead of one -capacitance. For this purpose the above-cited paper (Marashdeh et al, 2007) presents measurements of capacitance and power, dissipated by a resistive component. It seems that the measuring of current amplitude and phase shifting is more practical to determine the frequency characteristics of the examined object.…”

Section: Possibilities Of Temperature Distribution Analysis Using Ectmentioning

confidence: 99%

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Applications of Electrical Capacitance Tomography for Research on Phenomena Occurring in the Fluidised Bed Reactors

Porzuczek¹

2014

Chemical and Process Engineering

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The paper presents a review of current achievements in the Electrical Capacitance Tomography (ECT) in relation to its possible applications in the study of phenomena occurring in fluidised bed reactors. Reactors of that kind are being increasingly used in chemical engineering, energetics (fluidised bed boilers) or industrial dryers. However, not all phenomena in the fluidised bed have been thoroughly understood. This results in the need to explore and develop new research methods. Various aspects of ECT operation and data processing are described with their applicability in scientific research. The idea for investigation of temperature distribution in the fluidised bed, using multimodal tomography, is also introduced. Metrological requirements of process tomography such as sensitivity, resolution, and speed of data acquiring are noted.

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“…The Electrical Capacitance Tomography (ECT) is one of the imaging system developed for monitoring and measurement of industrial processes [1][2][3][4][5][6]. The system has been extensively evaluated for applications in hydrocarbons multi-phase flow measurement and monitoring [7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Comparative Performance Evaluation of Entropic Thresholding Algorithms Based on Shannon, Renyi and Tsallis Entropy Definitions for Electrical Capacitance Tomography Measurement Systems

Mwambela¹

2018

IJISA

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Abstract-The concept of entropy as a measure of information has been extensively applied in information theory and related fields. The complex nature of information has resulted in some proposed entropy definitions. In image processing, the entropy concept has been used in developing thresholding techniques based on maximum entropy principles for image segmentation, enhancement and object detection purposes. In this article, entropy definitions are analysed to establish their relationship and after that evaluate their performance in image thresholding. Static simulated data from Electrical Capacitance Tomography measurement system for annular and stratified flows in multiphase hydrocarbons production has been used. Performance evaluation results of thresholding algorithms using Renyi entropy has shown to improve the measurements, particularly for stratified flow regimes. The improvement is solely based on the entropy definition, and it has been observed the introduced controlling parameters do not affect its performance. Renyi entropic thresholding algorithm is relatively robust as it is independent of the controlling parameter q and the grey level resolution. Therefore, there is the potential possibility of using Renyi entropic thresholding to improve measurements in hydrocarbons flow measurement using Electrical Capacitance Tomography measurement system.

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A Multimodal Tomography System Based on ECT Sensors

Cited by 76 publications

References 19 publications

Measuring the Gas-Solids Distribution in Fluidized Beds -- A Review

Measuring the Gas-Solids Distribution in Fluidized Beds -- A Review

Applications of Electrical Capacitance Tomography for Research on Phenomena Occurring in the Fluidised Bed Reactors

Comparative Performance Evaluation of Entropic Thresholding Algorithms Based on Shannon, Renyi and Tsallis Entropy Definitions for Electrical Capacitance Tomography Measurement Systems

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