Abstract
“Synthesis and Optimization of Hybrid Membrane Desalination Processes”
Ahmed AlNouss, Sabla Alnouri and Patrick Linke
Texas A&M University at Qatar, P.O.Box: 23874, Education City, Doha, Qatar
Membrane desalination technology has become a valuable advanced water treatment
process to purify difficult water sources for potable use. The most common desalination
technologies are membrane processes; Reverse Osmosis (RO) and Nanofiltration (NF). The
studies of hybrid RO-NF desalination systems have shown potential advantages of higher overall
availability, low power demand, and improved water quality. Under the proposed title, a
systematic network synthesis approach is to be developed to evaluate the performance of a
hybrid membrane desalination plant consisting of NF and RO process in order to determine the
optimal process design and operating conditions for a given water production. This work is done
by the use of process superstructure representations and global optimization taking into account
desired process conditions and constraints that are associated with the hybrid RO-NF system.
The superstructure that captures all the structural and operational options is systematically
generated aiming to enable the extraction of the multiple different optimal designs using the
global optimization and giving a better visualization of the hybrid design network. The
optimization problems is formulated accounting for all the design decisions that are supported by
superstructure representation, based on numbers and types of units, flow rates, pressures, and
post treatment requirements and an economic objective function is utilized so as to provide
efficient of economical desirable configuration that capture all the significant capital and
operating costs, such as intake, pre and post treatment, along with the revenue from the value
extraction. The solution obtained by the proposed mathematical model would provide an
optimized design of the hybrid RO-NF desalination plant and this is illustrated using a case study
of sea water desalination with 35 ppt salinity.
Keywords: Optimization, Reverse Osmosis, Nanofiltration, Hybrid, Superstructure, Desalination