Thermodynamic optimisation of multi effect distillation driven by sensible heat sources

Boosted Multi-Effect Distillation for sensible low-grade heat sources: A comparison with feed pre-heating Multi-Effect Distillation

“…By addressing the unique nature of sensible heat sources, the theoretically available energy intake into the system by utilising the heat source down to ambient conditions is used as the benchmark instead of the actual energy used. We had demonstrated that this can lead to up to 40% increased production rates, when considered in the design process of a conventional parallel feed MED system [11]. This improvement is not achieved by using latent heat fundamentally better, but by better capitalising on the potential of waste sensible heat.…”

“…Sensible heat sources in contrast require specific approaches to unlock their potential, which are not addressed by these technologies and the common industrial benchmarks [11]. Consequently the typically market approach of simply adapting a steam driven design paradigm to sensible heat sources leads to thermodynamically inferior performance, which is limiting the economic application range significantly.…”

“…We had earlier demonstrated that when sensible heat is utilised, the non-isothermal nature of the heat input enjoins a compromise between the accessible temperature range and the number of effects so as to arrive at an optimal production rate [11,15]. As such a system design with a lesser number of effects, but consequently able to access a larger heating medium temperature differential can be superior to a highly efficient system in the conventional sense that displays a high performance ratio.…”

“…5) is a novel system tailored for sensible heat sources [11,13,15,17,18], and has been recently demonstrated to be viable by a pilot plant incorporating key design features [13]. In this system, the heating medium output stream of a conventional MED is passed through an additional evaporator module, the so called "booster module".…”

“…To this end, we compare our Boosted MED scheme [11,13,[15][16][17][18] against a feed-preheating MED scheme [19][20][21]. We consider a standard parallel feed MED plant, as in Fig.…”