Zhejiang Runtu (China)

Abstract A screened waveguide with a 90° elbow, which had a rubber surface to reduce noise generations and a steel/air interface to block noise propagations, was designed to measure local particle movements in certain directions. In the riser of circulating fluidized bed, the noise energy only accounted for 2.1% of the total energy received by the waveguide. Besides, the radial acoustic emission energy distribution detected via the waveguide was highly consistent with the radial solid flux distribution measured by the extraction probe. Furthermore, the radial flow patterns in the riser with Geldart D particles were measured under dense phase conveying by this new method, which always demonstrated as core‐annulus flows and the transition points (r/R) increased with decreasing solid–gas ratios.

Y 2 O 3 is a favourable reinforcement for the oxide dispersion strengthened superalloy due to its good high temperature stability, excellent strength and large elastic modulus. In this work, Y 2 O 3 is introduced into the K4169 superalloy aiming to improve its high temperature properties. The high quality Y 2 O 3 and K4169 powder mixture can be obtained with the addition of the process control agent of stearic acid after high energy ball milling, and the Y 2 O 3 /K4I69 composite with uniformly dispersed reinforcement of nanoscale Y 2 O 3 particles are finally synthesized with the ball-milled powders by using spark plasma sintering.

To modulate the matrix of purging plugs, MgO micropowder was introduced as a replacement to magnesia powder in alumina–magnesia castables, and the effect of MgO micropowder on the properties of alumina–magnesia castables and the possibility of developing chrome‐free castables were investigated. Experimental results showed that the introduction of MgO micropowder resulted in an improvement in the volume stability, strength, and thermal shock resistance of alumina–magnesia castables due to its high surface energy and small particle size. However, excessive amounts of MgO micropowder led to a lower densification, and there was a slight degradation in the performance of the alumina–magnesia castables. The slag resistance of the prepared alumina–magnesia castables was significantly better than that of the alumina–chrome castables. Microstructure and energy spectrum analysis showed that the formation of a solidified reaction layer, mainly consisting of spinel and CaAl 12 O 19 , was the major cause of the observed difference in slag resistance. In addition, the alumina–magnesia castables had a lower linear thermal expansion coefficient than that of the alumina–chrome castables at each experimental temperature, which effectively decreased the thermal stress during its service period, thus exhibiting good thermal shock resistance.