Abstract: The present invention provides an online measuring method of particle (such as bubbles, droplets and solid particles) velocity in multiphase reactor. The method based on an online multiphase measuring instrument includes the following steps: (1) the online multiphase measuring instrument is placed into the multiphase reactor, and then a particle image produced by two or more exposures are obtained; (2) the actual size of individual pixel in the particle image is determined; (3) valid particles are determined in the depth of field; (4) then the centroid coordinates are conversed to the actual length of the coordinates (xt,i, yt,i) and (xt+?t,i, yt+?t,i) using the actual size of individual pixel. Thus, the instantaneous velocity of particles can be calculated by V i = ( x t + ? ? ? t , i - x t , i ) 2 + ( y t + ? ? ? t , i - y t , i ) 2 ? ? ? t .

Abstract: An online multiphase measuring method of concentration and diameter distribution of dispersed phase particles in a multiphase reactor is provided in the present invention. The method is based on an online multiphase measuring instrument. The method described herein includes the following steps: (1) the online multiphase measuring instrument is placed in a multiphase system, and an image of the particles in the multiphase system is obtained; (2) valid particles are determined as: the particle that its Grad(?) is greater than or equal to Grad(?l/2) is labeled as a valid one; (3) the particle diameter is calculated by di=10×ni/N10; according to the equation ? = V c V = ? i n ? 1 6 ? ? ? ? d i 3 S × l , the concentration of the valid particles is calculated. The concentration and diameter of bubbles, droplets or solid particles can be obtained in real time and online measurement. The accuracy of this method is high.

Abstract: A micro-mixer and use thereof for synthesis of barium sulfate particles is disclosed. The micro-mixer includes feeding tubes, reservoirs, a mixing channel, a buffer reservoir and a sampling tube. The mixing channel is made of hydrophobic materials and processed into a spiral structure, in which baffles are set in interval arrangement at both sides of the channel wall. The types of the baffles include leaning-forward baffles, vertical baffles and leaning-backward baffles. Setting the baffles helps produce local secondary flow in the mixer, which enhances fluids mixing process. The micro-mixer is suitable to rapid reactions or precipitation processes, whose reaction time is much less than mixing time, and has broad application prospects in many fields involving mixing reaction such as pharmaceutical and chemistry industry.