Session: 12-06-04: Advanced Heat Sinks and Emerging Thermal Applications

Paper Number: 167165

Determination of Performance Characteristics and Efficiency Correlations in a Swirl Flow Separation Apparatus for Higher Salinity Desalination Applications 

According to recent estimates between 2 and 7 billion people would be impacted by water scarcity across the globe by 2050 [1]. The projections by the Texas Water Development Board in 2023 [2], suggest that Texas faces a critical water challenge. By 2070, the state’s water supply is expected to decrease by 18%, while water demand will increase by 9%. This imbalance could leave 25% of Texans facing municipal water shortages [3-6]. Currently, Texas relies on a mix of water sources: surface water accounts for 42% of the supply; groundwater contributes 50%; and reuse water, which includes treated wastewater, makes up 3% [7]. Commercial thermal desalination plants usually leverage static flash evaporation and vapor separation processes that occur separately in large chambers. Currently, static methods such as Multi-Stage Flash (MSF) or Multi Effect Distillation (MED) are widely used (in addition to Reverse Osmosis) for desalination [8]. These static methods have a large footprint, which in turn drives up the capital and production costs of the resulting purified water obtained. Desalination processes that leverage evaporation and vapor separation in the same chamber (dynamically) have smaller form factors which confer lower costs for desalination [9].

This study is primarily motivated by these pressing issues and aimed at developing a better understanding of a novel desalination apparatus to simultaneously generate vapor by dynamic flash evaporation and swirl flow separator to separate the produced vapor in the same apparatus for desalination application. The novel apparatus is geared for desalination of sea water, remediation of produced water from process-industries and other sources of saline water (such as brackish water) that are deemed unfit for human consumption. The objective of this study is to evaluate and determine correlations between various performance parameters such as thermal efficiency, collection efficiency, separation efficiency with the variation in flow rate for high salinity (10% salt by mass) applications. To achieve this goal, the experiments implement a novel swirl flow separation apparatus (at lab scale) for desalination. The experimental data analysis for determining performance parameters will be carried out based on similar reports in the literature [10-13].

The efficiency correlations derived in this study will aid in understanding the performance characteristics and optimizing the design parameters for the swirl flow desalination apparatus. The experiments with higher initial salt concentration of 10% by mass (i.e., salt concentration five times that of sea water), produce condensate after flash evaporation through 2 stages with salt concentrations about 0.01% (i.e., potable water for drinking). The apparatus was subject to reduced pressure (near vacuum) downstream and operated at supply (or feed) water temperatures in the range of 70°C-80°C with flow rates varying between 0.05–0.25 GPM (3.15-15.77 ml/s). The experimental data was further utilized to determine correlations between the flow rates and the efficiencies with a goal of identifying ideal operating conditions for maximizing the target thermal-conversion efficiency, phase separation efficiency and collection efficiency for best performance.

Presenting Author: Chinmay Chavan TAMU

Presenting Author Biography: Chinmay is a PhD student at TAMU

Authors:

Chinmay Chavan TAMU
Ashok Thyagarajan Southwest Research Institute
Debjyoti Banerjee Texas A&M University