Cogeneration of electricity and desalination outlook for yprus
Technion - Israel Institute of Technology Grand Water Research Institute Rabin Desalination Laboratory Chemical Engineering Department Energy Issues in Desalination Processes by Raphael Semiat - Cyprus Institute 20111
Driving Forces for Desalination R&D RelatedWater Need for Documents Global need, Industry, Agriculture, Remote Locations, Desertification, Etc. Cost Difference - (Industry/Urban - Agriculture) Cost Difference - (Thermal Processes - Membrane Processes) Technologies for Export 4RDL GWRI Technion 4
Sea Water Desalination According to government decisions (between the years 2001-2008) sea water desalination facilities are being built : (100) Hadera Construction phase. Production at 10/09 Completed facilities Ashkelon -BOT 108 MCM/Y (VID) Pre tendering stage Palmachim -BOO 30 MCM/Y (Via Full production (140) Maris) Planed Sorek Since 9/07 Ashdod – 100 MCM/Y (TK Mekorot) (30) In PQ process PalmachimPre tendering stage. (100) Sorek – more than 140 MCM/YFinancial Agreement Ashdod In ConstructionFull production 12/10 Hadera- BOT 100 MCM/Y (H2ID( (108) In bidding process Ashkelon Enlargement of about 100 MCM/Y Full production Since 12/05 Overall until 2013 = 600 MCM/Y Until 2020 = 750 5MCM/Y
Ashkelon PlantOn Sept 2006 completed first 100 Million m3 7
m m 0 80 0 ,0 13 e, ip , e l ip Ina ep fal p tk ot u DPE DE P 4”H 4”H 6 6 To w pipe pipe rete e cret 6 ” Conc Con 96 ” 9Palmachim 30MMm3/y. April 2006
Hadera – 2010Desalination plant H G100-129 million FM3/y E DA: Product water tank CB: Post-treatmentbuildingC: East SWRO, stage 2-4D: East SWRO, stage 1 BE: East gravity filterF: West gravity filterG: Admin, lab, control AroomH. West SWRO, stage 2-4I: West SWRO, stage 1
Man made polluted waters: Industrial, agriculture and urban effluents Modern Sewage Treatment Straining Secondary treatment Sludge/ solids treatment Adsorption Micro/Ultra- Energy Compost MBR Filtration Reverse-Osmosis Polishing Concentrate disposal 10 or Nano-Filtration RDL GWRI Technion
Desalination (Desalting, Desalinization) Process of removing salt from water – Practically – removing water from salt solutions Major processes: Ion Exchange Electro-Dialysis Other techniques Reverse Osmosis : olar distillers S Distillation Freezing Use of renewable energies (Solar, wind, nuclear, waves, etc.) Solvent extraction, clathrates Forward Osmosis, Membrane Distillation electrolytic capacitanceRDL GWRI Technion Air humidification
Thermodynamics – the concept of minimal energy andIrreversibilityMinimal energy needed to separate a component frombinary solution is equal to: p n a n R nR n W n l 0 nT 2 F lw d d Td n 1 p 06 n .9 2 2T p W lg 0n 1 1 0 n0 02 0 o d 1 0 p 2 T ga W . 9 o0 w 0 6l 1 Energy needed per 1m3 produced from an infinite source of 3.5% salt concentration seawater is 0.79 KWh/m3. For 50% recovery, the energy demand is 1.09 Kwh/m3.
. Different energy requirement for industrial desalination techniques . Source Technique Heat requirements Electricity Combined KWh/m3 (Thermal) required Energy KWhe/m3 demand KWhe/m3 Blank et al. (2006) RO - 4-6 4-6 MSF 40-120 (Thermal) 2.5-5 12-58 MED 30-120 (Thermal) 2-2.5 4-58 El-Nashar MSF 25-114 (Thermal) 4.8 Not clear El-Sayed (2001) MSF variations 34-102 2-2.2 17-47 Ophir & Gendel (2006) MVC 7.2-11.1 (electricity) 1.2 8.4-12.3 Ophir & Lukiec (2007) MED 4.8 1.2 6 Glueckstern, (2004) MED 6-12 MSF 10-16 RO 3.8 )4002( Wilf RO 3-4 Estimations for thermal units depend on GOR achieved in plant
Ireversibilties are accounted for energylosses due to friction, heat losses to theenvironment, heat losses due to minimaldriving forces and more.Actual energy needed is much higherthan the thermodynamic minimal energy.How can we compare the differenttechniques in terms of energy usage?
Energy balance, large scale plant (Glueckstern and Priel, 2002) Pumps Flow Diff. Energy KWh Specific Energy Head 3 No. m /h Bar Pump Total KWh/m3 Product Intake 6 2,200 1.0 77 462 0.07 Raw Water Supply 6 2,200 2.5 192 1,154 0.18 Feed Booster 12 1,042 7.7 281 3,368 0.54 Turbine operation for power saving High-Pressure Aggregate: 12 1,042 69.3 2,381 28,567 Pumps Turbine 12 521 73.0 -980 -11,763 Motors 12 1,444 17,323 2.77 Auxiliary + Lighting 400 400 0.06 Total 3.63 Pressure exchangers for power saving (estimate) High-Pressure Aggregate: 6 1,042 69.3 2381 14284 Pumps Pressure Depend 6252/n 66.0 - - exchangers on size/n Auxiliary pumps 6 1042 3.3 132 792 Motors 12 1,444 15,076 2.41 Auxiliary + 400 400 0.06 Lighting Total 3.26
Evaporation- distillation desalinationEvaporation of seawater, consumes about 650 KWh per m3…Pumping energy is needed to move waterto and from the plantPumping of cooling water for condensationReuse of the energy allowed reduction of thetotal consumption by a factor of GORGOR – Gained Output Ratio- usually 8-14Energy consumption is reduced inconnection with a power station
MSF DISTILLER (3,500 ton/unit, 30m W x 90m L x 15m H)20
Steam from power plant Thermal Desalination plantSchematics of a simplepower plant
O }Rankine Cycle on Pressure-Enthalpy Diagram 1-2 – electricitySteam engine for electricity production production line
Energy consumption for distillation techniques, based onexhausted steam and heat losses, at different temperatures. BPE values of seawater are included. Energy values -from steam tables. Temperature Electrical Boiling Point Energy consumption working range power potential elevation range GOR=10 GOR=16 of exiting steam in Power (Fabuss, 1980) Including pumping station 0C Kwhe/m3 KWhe 70-350C MED 17 0.98-0.34 6 100-350C MED 30.7 1.18-0.34 5.6 5 120-350C MSF 38.9 1.31-0.34 8.4 6.9
Distillation Forward Osmosis Direct osmosis Possible energy production Membrane cleaning In comparison with RO. Real energy consumption? Pumping energyMagnetic separation needed, distillation, cooling, etc.
Forward Osmosis Vapor compressor Gases to NCG out adsorbConcentrated seawater Diluted draw solution Feed seawater Concentrated draw solution Product water FO System Distillation Adsorption Basic sections in Forward Desalination
Energy recovery estimation in the FO process. Assuming 50% recovery, numbers are given per 1 m3 of product. Estimated EnergyDemand Consumption Comments (KWh/m3 product)Pretreatment and concentrate Pumping, filtration, etc. Similardisposal 1.7 to RO plantPumping of water and draw solutionsthrough the membranes 0.3 Equivalent value of 17 KWh/Evaporator distillation energy ton steam purged fromconsumption 4 electrical plant (only 0.25 tons needed)Cooling water at the distillation Energy needed to pump thecolumn 3 cooling water requiredCooling water for adsorbing draw Energy needed to pump thesolution gases 4 cooling water requiredVacuum compressor to pump non-condensable gases 4Credit for cooling water for steam Heat removal from 250 kg ofcondensation at power station -3 steam at the plantTotal 14 ±20% estimation error
Membrane Distillation - using“wasteenergy” Condensation chambers Stage Feed Water 1 n-2 n-1 n 2 ` Concentrate out External Heat source c c c c c o W o W W o W o W o W n a n a a n a n a n a d t d t t d t d t d t e e e e e e e e e e e n r n r r n r n r n r s s s s s a f a f f a f a f a f ti l ti l l ti l ti l ti l Back o o o o o o o o o o o to sea n w n w w n w n w n w Heat Recovery To reservoir Vacuum pump Condensate out (product) Brine flow Distillation membranes Feed pump chambers From SeaSchematic view of Membrane distillation design, based on MED technology
Osmosis-energy generation Ql-Q (P1-P1)Low-concentration Q High-concentrationsalt solution Ql (P1) salt solution Qh (P2) Qh+Q (P2-P2) Diluted salt solution Pressure Feed Exchange Seawater To Sea Power Generation Turbine Emax~Lpπ 2 /4 -QhP2
Subject Fuel Gas Gasoil Heavy fuel Coal Energy usage in Desalination - comparison7700Caloric value Kcal/Kg fuel 9000 10750 10000Caloric Value Kwht/Kg fuel 10.5 12.5 11.6 9Electricity production (45% eff.)Kwhe/Kg fuel large Power station 4.7 5.6 5.2 4Electricity production (80% eff.)High efficiency gas turbineKwh/Kg fuel 8.4Capacity - Seawater Desal (50%Recovery) m3/ kg fuel 1.3 1.6 1.5 1.2 80% efficiency 2.4Fuel consumption/ tonDesalinated water Kg fuel /m3 0.7 0.6 0.7 0.9 80% efficiency 0.4How many km can I drive with 1m3 Desal water fuel consumption? 2-7 2-6How many hours of AC - singleroom (2.5 Kw-h) can I operate? 1.4
Household Energy Consumption Electricity, transportation and desalinated water…A small family, consumes water at a rate of 18 m3/month,1200 KWh of electricity /month, Drives 1500 km/month, consumes 160 liter gasoil/monthEnergy consumption assuming only desalinated seawater used - 140 KWh/month (fuel value)Energy consumption - driving a car - 1500 KWh/month (fuel value)Energy consumption - electricity - 1200/0.45=2667 KWh/month (fuel value)Energy for desalination/ energy for transportation - 9.3%Energy for desalination/ energy for electricity - 2.6%Energy for desalination/ total energy consumption - 3.4%Can we save 3.4% in our household energy consumption?Where we should put our energy for use? In water? In high energy consuming cars? In overused AC?A nature trip of 300Km from Tel Aviv to the Negev or the Galilee, in a four wheels drive, is equivalent in terms of energy to desalinated seawater consumption of a family of four people (16m3/month) of 7 months!!!
צריכת האנרגיה בישראל – ויקיפדיהEnergy consumption in IsraelTotal energy imported and produced in Israel in 2006 is 24.06equivalent million tons oil – 1.04*10^18JoulElectricity – 40%. Fuels products – 43%. Palestinian Authority – 13%.Solar heaters – 3%.Electricity production – 46,175 millions KWh (2006) 50,161 millionsKWh (2008) Rate of change – 1.7-2,7%/year.Yearly energy consumption expected by 2013 for desalinated water –3.7KWh/m^3*600 million m^3 = 2220 millions KWhElectricity for desalination/total electricity production – 4.42%Electricity for desalination/total energy consumption – 1.77% !!!!!!!!!!Correction for PA – 2.0%Correction for 10% increase in total energy consumption – 1.85%
Desalination and proper water usage Other costs should be included besides Energy• Cost of water in negligible for regular household• Cost of water is tolerable for most industries• Cost of water is significant in agriculture Make better usage of water: – Use of greenhouses – Use Drip-Irrigation – save 30-90% of water consumption by other irrigation techniques – reduce the cost problem
200-250 m2 are needed to make 1 m3 water a day!39
Solar Desalination Aqaba Jordan Sept 200540
Water is needed in locations where agriculture is still the basis for life. Simple agriculture cannot afford even the currently relatively low costs. It is a global question of the same type as the usage of alternative energy sources to solve environmental-pollution problems. The future of mankind depends on finding the proper answers to those questions, in addition to the quest for global peace.41 41 RDL GWRI Technion