Indexed by:
期刊论文
First Author:
Jiang, Xiaobin
Correspondence Author:
Wang, JK (reprint author), Tianjin Univ, Sch Chem Engn & Technol, State Res Ctr Industrializat Crystallizat Technol, 97 Weijin Rd, Tianjin 300072, Peoples R China.
Co-author:
Hou, Baohong,He, Gaohong,Wang, Jingkang
Date of Publication:
2012-12-24
Journal:
CHEMICAL ENGINEERING SCIENCE
Included Journals:
SCIE、Scopus
Document Type:
J
Volume:
84
Page Number:
120-133
ISSN No.:
0009-2509
Key Words:
Crystal Layer Growth; Diffusion; Melt Crystallization; Parameter
identification; Separations; Simulation
Abstract:
This paper was concerned with the model development and experimental validation of the detailed crystal layer growth and multi-ions impurity distribution process in the falling film melt crystallization (FFMC) model. The phosphoric acid (PA) was separated and purified by FFMC to obtain a hyperpure phosphoric acid (HPA), which was a vital electronic chemical in IT industry. To establish a valid model, which offered an easy and convenient path of the simulation, dynamic heat and mass balance, approaches were adopted to describe the variation of crystal layer growth rate along the crystallizer. An impurity balance approach was adopted to describe the change of distribution coefficient for multi-ion impurity. A criterion was proposed to determine the formation of branched-porous (B-P) structure. The model was validated by experimental results with various equipments and operational conditions and a good agreement was obtained. The effective distribution coefficient K-eff for multi-ion impurities were less than 0.2 (Na+), 0.25 (Fe3+) and 0.35 (Ca2+) with proper operation conditions. The resulting model was directly exploited to understand crystal layer growth and impurity distribution behaviors in FFMC from laboratory to industrial scale. More significantly, the model proposed a method for the separation effect evaluation and the key operational conditions (feed rate and cooling rate) determination which could readily develop optimal crystal layer growth route during industrial crystallization. In addition, the model was a vital base to describe the subsequent purification step of FFMC: sweating process. (C) 2012 Elsevier Ltd. All rights reserved.
Translation or Not:
no
