טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentIrena Brook
SubjectCharacterization of Precipitation Potential of Low
Solubility Salts in Seawater Concentrates
DepartmentDepartment of Chemical Engineering
Supervisors Professor Emeritus Semiat Raphael
Professor Emeritus Hasson David
Full Thesis textFull thesis text - English Version


Abstract

Boron contamination of the permeate in seawater RO desalination is commonly prevented by increasing of the concentrate pH level in a rather elaborate multi-pass processing system. The reason for this cumbersome processing is the need to control the scale precipitation tendency induced by the pH increase. The lack of sufficient knowhow on the scaling propensity of seawater at various supersaturation levels hampers optimal design of boron control system. The main objective of the present work was to provide scaling propensity data so as to assist design of boron reduction processes and explore the possibility of boron control by a single pass RO. Membrane tests were conducted to determine induction periods and scaling threshold limits with and without an anti-scalant. The tests were carried out on Pacific Sea Water concentrates of 0% and 50% permeate recovery either with Mg present or in the absence of Mg in continuous tubular and spiral wound flow systems. Results of this study suggest that the concept of a single pass RO has a considerable potential for simplifying the present rather cumbersome boron control processes flow sheets.