OICC Press International Journal of Energy and Environmental Engineering 2251-6832 4 1 (December 2013) 2013 02 21 Experimental investigations on the phase equilibrium of semiclathrate hydrates of carbon dioxide in TBAB with small amount of surfactant 10.1186/2251-6832-4-11 EN Abhishek Joshi Petroleum Engineering Program, Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 600 036, IN Jitendra S Sangwai Petroleum Engineering Program, Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 600 036, IN Kousik Das Petroleum Engineering Program, Department of Ocean Engineering, Indian Institute of Technology Madras, Chennai, 600 036, IN Nagham Amer Sami Department of Petroleum Engineering, College of Engineering, University of Baghdad, Baghdad, IQ Department of Chemical Engineering, AC Tech Campus, Anna University, Chennai, 600 025, IN Journal Article 2013 02 21 Abstract Experimental studies are carried out on a semiclathrate hydrate system of carbon dioxide in tetra- n -butyl-ammonium bromide (TBAB) with a small amount of surfactant, sodium dodecyl sulfate (SDS), for 5, 10, and 20 wt.% TBAB to determine the phase equilibrium temperature and pressure conditions. It is observed that the presence of SDS did not influence the equilibrium conditions of the semiclathrate hydrate. Re-nucleation (memory) effect of semiclathrate hydrates of CO 2 is studied for few cases of TBAB concentration in an aqueous solution. The equilibrium pressure and temperature conditions obtained for memory effect and regular experimental run without memory effect were observed to be quite close. It is concluded that in the case of no memory effect, with increasing TBAB percentage in the system, the time required for nucleation is reduced. For the same TBAB concentration, the incipient pressure and temperature required for nucleation and re-nucleation of semiclathrate hydrates increase while the time required for re-nucleation decreases.