Liquid-continuous impinging streams (LIS) has been proved experimentally to have the valuable features of efficient micromixing and strong pressure fluctuation,both which favor processes occurring on molecular scale [1],including crystallization from solution.Well micromixing provides uniform supersaturation,a very important condition for crystals of larger and uniform sizes,and,with strong pressure fluctuation together,promotes kinetics of crystal-growth [2].Based on the investigations supported by NNSFC,several crystallizers employing LIS,non-rotating flow impinging stream vacuum crystallizer (NRISVC),non-rotating flow impinging stream heat-exchanging crystallizer (NRISHEC),and impinging stream evaporating crystallizer (ISEC),were developed.The crystallizers employ the basic flow configuration of vertical circulative two-impinging streams.The upper and lower propellers with opposing screw directions and driven by the same motor draw the slurry streams from the inlets of the upper and lower drawing tubes and push them to flow through the drawing tubes towards the center of the crystallizing container where the streams impinge against each other.The interaction between the two streams in impingement creates excellent micromixing condition and thus provides very uniform supersaturation for crystallization.After impingement the combined and well-mixed stream becomes radial flow outwards,and then is divided into two streams at the cylinder wall,which flow back to the inlets of upper and lower drawing tubes,respectively,through the annular chambers between the outside walls of the drawing tubes and the inner wall of the cylinder,and so on.Now,totally 25 sets of the first two crystallizers of large scale,each with an effective volume of 36 or 20 m3,have been used indus~ially in production systems for Pentaerythritol,Taurine,and Hexanedioic acid in various companies,of which the earliest ones have been operated for nearly three years,and exhibited well performances in great power saving,higher volumetric capacity,and yielding crystals with larger and uniform sizes.