Xu Chuanlong

Effect of pipeline thickness on electrical capacitance tomography

For the purpose of analyzing the effect of pipeline thickness on ECT system include sensor and image reconstruction, radius-electrode ratio is defined as the ratio of inner and outer radius of pipeline. The rules of 8-electrode sensor parameters such as capacitance, capacitance change, and change rate of capacitance and sensitivity map are discussed by ANSYS and Matlab, which are combined to simulate sensor characteristic. With the increase of radius-electrode ratio, capacitance sensitivity to inner media increases, and the effect of pipeline thickness on capacitances of four typical inter-electrode pairs is much different under the same inner radius. LBP algorithm is adopted to reconstruct the ECT images of stratified flow, core flow and annular flow with different radius-electrode ratios. Simulation results show that image error under high radius-electrode ratio is small, and the image reconstructed from stratified flow is better than the ones from core flow and annular flow, especially in the condition of low radius-electrode ratio. As a result, ECT with low radius-electrode ratio is benefit to image reconstruction.

Improved algorithms of differential optical absorption spectroscopy for monitoring SO2, NO2 from flue gas

Valuable achievements in differential optical absorption spectroscopy (DOAS) for monitoring atmospheric trace gas have been made in the past decades. However, in flue gas monitoring, it is difficult to monitor the pollutant gases at low optical density. In this paper, two improved inversion algorithms based on the genetic algorithm and Kalman filter, respectively, were developed to accurately calculate the concentrations of SO2 and NO2 from flue gas. Experimental results show that the improved algorithms have the detection limit of 10 ppm and have a zero drift of 1 ppm at a light path length of 0.5 m. Additionally, the improved algorithms of DOAS combined with the traditional DOAS algorithm can broaden the measurement range of pollutant gases by appropriately setting critical values for the maximum value of the differential optical density.

Charging of coal powder particles in dense phase pneumatic conveying system at low pressure

A non-contact measurement method, namely an electrostatic probe, for particle charging characteristics determination is introduced in the paper. Using the probe, the charging trends of the pulverized bituminous coal in a dense phase pneumatic conveying system at low pressure were investigated for gas superficial velocities in a range of 6-10 m/s and particle concentrations in a range of 128-230 kg/m3. The observations indicated that increasing the coal particles concentration leads to an increase in charge level of the pulverized coal particles and then a decrease, and a peak of the charge level is experienced in the range of 150-160 kg/m3. The charges carried by the coal particles increase with the increase of gas superficial velocity in the pipeline, and then reach saturation values.