Design Of Electromagnetic Tomography System Based On TMR

The core equipment of residual oil hydrogenation is a gas liquid solid three-phase fluidized bed.It is an important basis to deeply understand the operation state of the fluidized bed by means of non intrusive method to measure the distribution of catalyst in the fluidized bed.Based on the principle of electromagnetic induction,electromagnetic tomography is mainly used for space detection of conductivity materials,and most of them are coil detection,which is difficult to be used for the detection of modified high permeability catalyst.Therefore,an electromagnetic tomography technique based on magnetic permeability is proposed,which can be used for the detection of solid catalysts,so as to deepen the study of petroleum hydrogenation technology.The technique and system of measuring permeability distribution by electromagnetic tomography are studied.1 Through COMSOL simulation software,a single coil excitation EMT system simulation model is established.The excitation coil parameters of the 8 coil EMT system are determined by simulation.By comparing the shortcomings of coil detection and determining the range of magnetic induction intensity of each detection point in different space conditions under the coil parameters,the magnetic sensor type is selected.2 According to the selected magnetic sensor chip manual,the front-end circuit and the design of signal processing circuit are completed.3 The eight coil EMT system is built,and the system control programming is completed.The excitation detection channel can be selected arbitrarily,and the excitation frequency can be adjusted.4 The sensitivity matrix is established according to the field extraction method and the simulation perturbation method.It is found that the sensitivity matrix calculated by the simulation perturbation method is closest to the true value.Two kinds of common image reconstruction algorithms are selected to realize electromagnetic tomography based on permeability.