Key Operational Variables in Mechanical Vapor Compression for Zero Liquid Discharge Processes: Performance and Efficiency Evaluation

The mechanical vapor compression (MVC) is an appealing technology for Zero Liquid Discharge (ZLD) processes, particularly in the context of the increasing global demand for freshwater and the protection of the natural environment. This approach supports the development of circular emerging technologies aligned with the Sustainable Development Goals. In this framework, an extended analysis is conducted to evaluate the performance of the MVC system under various operating conditions, with the objective of assessing the impact on energy consumption and distillate production. Reducing the consumption ratio is essential for enhancing process efficiency and advancing a more sustainable process. For this purpose, the paper examines how fluctuations in compressor boundary conditions affect temperatures and pressures. Moreover, feed brine concentration salinity is varied and related to the distillate flow. In the paper, a real ZLD process case study is provided, with experimental data collected. The real data correspond to four different operating conditions (scenarios), verifying that higher evaporation temperatures and lower compression ratio enhance the performance of such systems and lead to increased distillate production. In addition, the energy analysis reveals a consumption range of 165–214 kWh/m3 feed. Incoming electrical conductivities of up to 100 mS/cm are acceptable without scaling, with periodic HNO3 cleanings recommended. The proposed operating ranges can also be applied to other mechanical evaporation systems for wastewater treatment, desalination processes and ZLD technologies, or transferred to other locations.