Primary Energy Consumption for the Efficiency Comparison of all Desalination Processes

Transcription

1 Primary Energy Consumption for the Efficiency Comparison of all Desalination Processes Muhammad Wakil Shahzad (Research Scientist) Water Desalination & Reuse Center, King Abdullah University of Science & Technology, Saudi Arabia

2 Overview Desalination in GCC Performance Ratio Definition: whole World is wrong? Desalination Energy: Derived & Primary CCGT+Desalination Analysis Universal Performance Ratio (UPR) Desalination Hybrids Lab to Industry: A way Forward

3 Water Scenario in Bahrain Bahrain currently produces 142 million gallons of water a day. 33% increase and 400 million investment predicted.

4 Desalination in GCC Q, in TBT 70 o C Stage-1 ΔT for MED operation Stage-n 40 o C MED operation limit 30 o C Condenser Cooling tower operation limit Q, out

5 Performance Ratio (PR) PR = Equivalent heat of evaporation of distillate production Energy input kwh elec m 3 + kwh ther m 3 Inherent Weaknesses No distinction between grade of energy Susceptible to conversion efficiencies Predicted on an arbitrary constant, 2326

6 Desalination Energy Rabigh Reverse Osmosis Plant The world's first 3-stage RO plant Total Capacity: 192,000 m 3 /day Yanbu MED Desalination Plant 5 effects, PR=9, TBT=60C Total Capacity: 68,190 m 3 /day Yanbu-3 MSF Desalination Plant 25 fashing stages, 9-units, TBT=114C Total Capacity: 288,000 m 3 /day/unit Reverse Osmosis Multi-Effect Distillation Multi-Stage Desalination Electricity (kwh_ elec /m 3 ) 5.2 Electricity (kwh_ elec /m 3 ) 2.6 Electricity (kwh_ elec /m 3 ) 3.75 Thermal Input (kwh_ ther /m 3 ) - Thermal Input (kwh_ ther /m 3 at 60 o C) 76.0 Thermal Input (kwh_ ther /m 3 at 114 o C ) Questions: (1) Which of the three processes is more efficient? (2) Are the derived units, kwh, a suitable units to be used for the efficiency comparison? 79.5

7 Derived Energy to Primary Energy Primary Energy to Electricity Primary Energy to Thermal Primary energy Derived energy Primary energy Derived energy 2.12 kwh pe 1 kwh elec 1 kwh pe 29.5 kwh ther For MSF 120C, CF thermal = For MED (at 65C), CF thermal = UPR h fg kwh 3.6 CF elec kwh elec m 3 + CF ther ther m 3

8 CCGT+ Desalination Process Process Each process have thermodynamic lost work to produce useful effect. Out in Ex = m Conventional Energetic method (%) (Ignoring lost work) out in h T o Proposed Exergy method (%) These losses must be charged to corresponding useful effect. out in s % over/less charged as compared with exergy method GT (including combustor, air compressor) % ST (HRSG, HP, MP and LP) % MED Desalination % Desalination over-charged by energy method 393% Water cost (Opex) by exergy method $/m3 Water cost (Opex) by energy method (conventional) 1.049$/m3 Water over-charged by energy method $/m3 Savings for a 30.8x106 m3/day desalination capacity of the GCC countries (2015) = 9.16 billion $/yr *Fuel cost used for calculation= US$5 per thousand cu ft or 1055 MJ.

9 KWhpe/m 3 = Desalination processes Electrical energy consumption(kwh elec /m 3 ) Thermal energy consumption (kwh ther /m 3 ) Weighted factor for CCGT Steam for MED processes = Primary energy UPR= hfg/{3.6 x (kwh pe /m 3 )}. Universal Performance Ratio (UPR) Derived energy Conversion efficiency Exergy destruction of primary energy SWRO 3.5 NA MSF % 3.4% MED MEDAD % 3.4%

10 UPR contd..

11 Desalination Hybridization to Overcome Limitations

12 MED+AD Pilot at KAUST

13 KAUST Pilot Experimentation 2.1LPM *=4.1 LPM *Last stage vapors adsorbed on AD beds

14 Desalination Processes Comparison

15 Conclusions All desalination technologies must be compared on common platform, primary energy consumption. Performance ratio must be defined based on primary energy, not on derived energy basis. Currently, all desalination processes are operating 10-13% of TL, not sustainable for future water supplies. Future sustainability can only be achieved with 25-30% of TL, by innovative hybrid desalination processes.

16 A Global Award Technology H.E. Prince Turki bin Abdullah (former governor of Riyadh) presenting award to Professor Kim Choon (KAUST), H.E. Abdullah Al Hussayen, Minister of Electricity of SA, H.E. Dr Abdulrahman Al Ibrahim, Governor of SWCC, Professor Jean-Lou Chameau, President of KAUST, Dr. Adil Bushnak, Moya Bushnak MEDAD Technology winner of Aramco-GE Global Innovation Challenge Award. Below USD 0.5 / m3, life cycle costing.

17 Translation to Industry: Inauguration of KACST AD Plant (Feb 21, 2017)

18 Yanbu MEDAD Hybrid MOU

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