Local Holdups and Phase Propagation Velocity Measurement in GLSCFB Riser Using Electrical Resistance Tomography and Optical Fibre Probe

نویسندگان

  • S. A. Razzak
  • S. Barghi
  • J-X. Zhu
چکیده

The application of Gas-Liquid-solid circulating fluidized beds (GLSCBE) has increased recently in chemical, petrochemical and biochemical industries. Electrical Resistance Tomography (ERT) and optical fibre probe were applied to investigate local phase holdups distribution. Since ERT is applicable only to conductive phase(s), e.g. liquid phase in this study, optical fibre probe was employed simultaneously to quantify all three phases. Water was used as continuous and conductive phase, air as the gas phase and glass beads as solid non-conductive phases. The local conductivity measured by a number of electrodes located at the periphery of the plane, was then further converted into a local phase concentration distribution based on Maxwell’s relation. Fibre optic probe was also employed to measure gas holdup independently. A new model was developed to exploit the fibre optic data in differentiating gas bubbles from solid particles in the riser. Gas holdup was higher in the central region and decreased radially, while opposite trend was observed with solid holdup due to the drag forces imposed on solid particles by the gas and liquid upward flow in the riser. By applying cross correlation between the data obtained at two different levels in the riser, the propagation velocity of the nonconductive phase was obtained. Propagation velocity was higher in the central region compared to the wall region and increased with increasing liquid superficial velocity

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Solids Holdups in the Fully Developed Region of Circulating Fluidized Beds

The present work focuses on developing correlations for better prediction of solids holdups in the fully developed region of cocurrent upflow and downflow two-phase flow. Systematic experiments were carried out in two CFB risers (15.1m and 10.5m high, respectively, but with the same 0.1 m i. d.) and a 9.3 m high, 0.1 m i. d. CFB downer. The experimental results obtained from about 200 sets of o...

متن کامل

Effect of Nonlinear Phase Variation in Optical Millimetre Wave Radio over Fibre Systems

In this paper, we propose an optical millimetre wave radio-over-fibre (mm-wave RoF) system that uses a dual drive Mach Zehnder modulator (DD-MZM), which is biased at the maximum transmission biasing point, to generate an optical double sideband-suppressed carrier. The input to the DD-MZM are binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 8-phase shift keying (8-PSK) and...

متن کامل

Employing dual frequency phase sensitive demodulation technique to improve the accuracy of voltage measurement in magnetic induction tomography and designing a labratoary prototype

Magnetic induction tomography (MIT) is a promising modality for noninvasive imaging due to its contactless technology. Being a non-contact safe imaging technique, MIT has been an appropriate method in compare to other electrical tomography. In this imaging method, a primary magnetic field is applied by excitation coils to induce eddy currents in the material to be studied and a secondary magnet...

متن کامل

Optical Fibre Interferometric System for Doppler Effect Measurement

The optical fibre laser Doppler velocimetry (LDV) is a technique used for the velocity measurement of fluid flows. The two-dimensional directional LDV using a special technique based on generation of heterodyne signals of differential carrier frequencies has been described in literature [1,2]. The capability of simultaneous measurement of three orthogonal velocity components has also been prese...

متن کامل

ECT and LS-SVM Based Void Fraction Measurement of Oil-Gas Two-Phase Flow

A method based on Electrical Capacitance Tomography (ECT) and an improved Least Squares Support Vector Machine (LS-SVM) is proposed for void fraction measurement of oil-gas two-phase flow. In the modeling stage, to solve the two problems in LS-SVM, pruning skills are employed to make LS-SVM sparse and robust; then the Real-Coded Genetic Algorithm is introduced to solve the difficult problem...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2008