Application of the Boosted MED process for low-grade heat sources — A pilot plant

• A pilot plant for the Boosted MED process has been demonstrated.
• The performance was evaluated from 68 to 93 °C heat source temperature.
• Significant boosting potential at low temperatures has been validated.
• Mass flow and temperatures of the vapour are sufficiently high for utilisation.
• A very high distillate quality has been achieved.

The Boosted MED technology is a thermal desalination process dedicated to low-grade waste heat sources. By augmenting the standard Multi Effect Distillation (MED) process with an additional Booster Module, the system is capable of further exploiting the heating medium output stream of the basic MED system and boosting the freshwater production of the system in an effective manner.This paper experimentally evaluates the principal design basis of the Boosted MED technology. A state-of-the-art pilot plant consisting of two evaporator modules in a serial connection is used to assess the additional vapour production from the downstream evaporator, which adequately mimics the booster unit, at heat source temperatures of 68 °C to 93 °C, cooling water temperatures of 20 °C to 35 °C, and two feedwater salinities.Additional vapour production rates ranging from 33% to 57% at sufficiently high temperatures demonstrate the general viability of the design hypothesis. The stable operation and the very high distillate quality achieved by the pilot plant augur well a favourable system characteristic.The process simulation model developed for designing and optimising Multi Effect Distillation based technologies has been experimentally demonstrated to be consistent with the pilot plant performance.

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