Three-phase material distribution measurements in a vertical flow using gamma-densitometry tomography and electrical-impedance tomography

George, D. L.; Shollenberger, K. A.; Torczynski, J. R.; O’Hern, Timothy J.; Ceccio, Steven L.

doi:10.1016/s0301-9322(01)00042-8

Cited by 36 publications

(32 citation statements)

References 17 publications

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“…In addition, the expensive cost and operation, and the added human-protection requirements of a GDT system are impractical for widespread industrial use, especially if a less expensive and safer EIT system is capable of making the same two-phase measurements, and making them more quickly. The authors have also used EIT in combination with GDT to obtain quantitative measurements of phase-volumefraction distributions for three-phase flows in nonconducting vessels (George et al 1999;George et al 2001a;George et al 2000c).…”

Section: Summary Of Previous Workmentioning

confidence: 99%

“…Material distributions in three-phase flows in insulating vessels have previously been measured by combining the EIT and GDT techniques (George et al 2001a). The reconstruction procedure used to make these measurements is reviewed here and is applied to make the three-phase material distribution measurements in electrically conducting vessels presented in this study.…”

Section: Combined Eit and Gdt For Three-phase Measurementsmentioning

confidence: 99%

“…To account for these two different size distributions, a recursive, bimodal application of the Maxwell-Hewitt relation was suggested (George et al 2001a) and was used for the three-phase results presented in this study.…”

Section: Combined Eit and Gdt For Three-phase Measurementsmentioning

confidence: 99%

“…(15), (23), and (28) must be solved simultaneously to determine the gas volume fraction. A closed-form solution was previously reported (George et al 2001a) and is repeated here with a correction of the sign preceding the square root in Eq. …”

Section: Combined Eit and Gdt For Three-phase Measurementsmentioning

confidence: 99%

See 3 more Smart Citations

Electrical-Impedance Tomography for Opaque Multiphase Flows in Metallic (Electrically-Conducting) Vessels

Liter¹,

Torczynski²,

Shollenberger³

et al. 2002

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A novel electrical-impedance tomography (EIT) diagnostic system, including hardware and software, has been developed and used to quantitatively measure material distributions in multiphase flows within electrically-conducting (i.e., industrially relevant or metal) vessels. The EIT system consists of energizing and measuring electronics and seven ring electrodes, which are equally spaced on a thin nonconducting rod that is inserted into the vessel. The vessel wall is grounded and serves as the ground electrode. Voltage-distribution measurements are used to numerically reconstruct the time-averaged impedance distribution within the vessel, from which the material distributions are inferred. Initial proof-of-concept and calibration was completed using a stationary solid-liquid mixture in a steel bench-top standpipe. The EIT system was then deployed in Sandia's pilot-scale slurry bubble-column reactor (SBCR) to measure material distributions of gas-liquid two-phase flows over a range of column pressures and superficial gas flow rates. These two-phase quantitative measurements were validated against an established 3 gamma-densitometry tomography (GDT) diagnostic system, demonstrating agreement to within 0.05 volume fraction for most cases, with a maximum difference of 0.15 volume fraction. Next, the EIT system was combined with the GDT system to measure material distributions of gasliquid-solid three-phase flows in Sandia's SBCR for two different solids loadings. Accuracy for the three-phase flow measurements is estimated to be within 0.15 volume fraction. The stability of the energizing electronics, the effect of the rod on the surrounding flow field, and the unsteadiness of the liquid temperature all degrade measurement accuracy and need to be explored further. This work demonstrates that EIT may be used to perform quantitative measurements of material distributions in multiphase flows in metal vessels.

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Section: Summary Of Previous Workmentioning

confidence: 99%

Section: Combined Eit and Gdt For Three-phase Measurementsmentioning

confidence: 99%

Section: Combined Eit and Gdt For Three-phase Measurementsmentioning

confidence: 99%

Section: Combined Eit and Gdt For Three-phase Measurementsmentioning

confidence: 99%

See 2 more Smart Citations

Electrical-Impedance Tomography for Opaque Multiphase Flows in Metallic (Electrically-Conducting) Vessels

Liter¹,

Torczynski²,

Shollenberger³

et al. 2002

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show abstract

“…The most typical applications of EIT include monitoring of multiphase flow (George et al, 2001) and mixing processes (Kourunen et al, 2008), also with chemical reactions during mixing (Stanley, 2006). This method is likewise applicable to the study of combustion (Yan et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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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Effect of sparger design on hydrodynamics of a gas recirculation anaerobic bioreactor

Varma

Al‐Dahhan

2007

Biotechnol. Bioeng.

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The effects of sparger design and gas flow rate on, gas holdup distribution and liquid (slurry) recirculation velocity have been studied in a surrogate anaerobic bioreactor used for treating bovine waste with a conical bottom mixed by gas recirculation. A single orifice sparger (SOS) and a multi-orifice ring sparger (MORS) with the same orifice open area and gas flow rates (hence the same process power input) are compared in this study. The advanced non-invasive techniques of computer automated tomography (CT) and computer automated radioactive particle tracking (CARPT) were employed to determine gas holdup, liquid recirculation velocity, and the poorly mixed zones. Gas flows (Q(g)) ranging of 0.017 x 10(-3) m(3)/s to 0.083 x 10(-3) m(3)/s were used which correspond to draft tube superficial gas velocities ranging from 1.46 x 10(-2) m/s to 7.35 x 10(-2) m/s (based on draft tube diameter). Air was used for the gas, as the molecular weights of air and biogas (consisting mainly of CH(4) and CO(2)) are in the same range (biogas: 28.32-26.08 kg/kmol and air: 28.58 kg/kmol). When compared to the SOS for a given gas flow rate, the MORS gave better gas holdup distribution in the draft tube, enhanced the liquid (slurry) recirculation, and reduced the fraction of the poorly mixed zones. The improved gas holdup distribution in the draft tube was found to have increased the overall liquid velocity. Hence, for the same process power input the MORS system performed better by enhancing the liquid recirculation and reducing the poorly mixed zones.

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Three-phase material distribution measurements in a vertical flow using gamma-densitometry tomography and electrical-impedance tomography

Cited by 36 publications

References 17 publications

Electrical-Impedance Tomography for Opaque Multiphase Flows in Metallic (Electrically-Conducting) Vessels

Electrical-Impedance Tomography for Opaque Multiphase Flows in Metallic (Electrically-Conducting) Vessels

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

Effect of sparger design on hydrodynamics of a gas recirculation anaerobic bioreactor

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