Iman Asghari - Chemical and Petroleum Engineering Department, School of Engineering, Shiraz University, Iran
Feridun Esmaeilzadeh - Corresponding Author: Chemical and Petroleum Engineering Department, School of Engineering, Shiraz University

The rapid expansion of a supercritical solution (RESS) process is a promising method for the production of small, uniform and solvent-free particles of solutes. The RESS containing a nonvolatile solute leads to loss of solvent power by the fast expansion of the supercritical solution through an adequate nozzle, which can cause solute precipitation. The nozzle configuration plays an important role in RESS method and has a great effect on the size and morphology of the precipitated particles. In this work, a RESS apparatus was set up and CMC submicron particles were prepared successfully with the supercritical carbon dioxide. The experiments were carried out to investigate the effect of parameters such as extraction temperature (308-328K), extraction pressure (140-220 bar), spraying distance (1-3 cm) besides the nozzle configuration. The RESS process could produce ultrafine spherical particles (0.110 to 1.3 μm) of CMC as reflected by SEM observations. However The average size of the unprocessed particles were (1-100 μm) with average of 15 μm.

Carboxymethylcellulose (CMC); Drilling Fluid; Rapid expansion of supercritical solution; Nanoparticles