Model based optimal control for SWRO process based on pilot plant data

Abstract

Generally, operating values such as reverse osmosis (RO) recovery rates are adjusted to a desired power consumption cost during the initial stage of design. However, the power consumption is dependent on changes in membrane permeability associated with seasonal/daily variations of seawater conditions such as temperature, salinity and potential of Hydrogen (pH). These variations might be a vital contributing factor to the difference from desired cost. In order to solve this problem, it is desirable to develop optimal control which can minimize specific energy consumption (SEC) automatically. This paper proposes an optimal operational approach for tracking a minimum SEC under the variations of seawater conditions. In this approach, numerical simulations are carried out to estimate SEC and determine operating values. Several simulation results demonstrate the effectiveness of the proposed controller compared with the constant RO recovery rate.

Keywords:

• Recovery rate
• Specific energy consumption
• Optimal control
• 2-pass RO system
• Langelier Saturation Index