Presentation on theme: "By Seong Taek Bpang Mar/07/2011"— Presentation transcript:
1 By Seong Taek Bpang Mar/07/2011 Desalination A part of an alternative solution to meet the water in demand?NotesUse the Notes section for delivery notes or to provide additional details for the audience. View these notes in Presentation View during your presentation.Keep in mind the font size (important for accessibility, visibility, videotaping, and online production)Coordinated colorsPay particular attention to the graphs, charts, and text boxes.Consider that attendees will print in black and white or grayscale. Run a test print to make sure your colors work when printed in pure black and white and grayscale.Graphics, tables, and graphsKeep it simple: If possible, use consistent, non-distracting styles and colors.Label all graphs and tables.By Seong Taek BpangMar/07/2011
2 Table of Contents Definition/Back ground Operating process Types of desalinationWorld trendIssue of desalination* Note that this slide is not necessary for weekly status meetings
3 Current Status of water According to IDAFresh water is app 3% of world water depositLess than 30 % of the water, ground and surface water, are available for daily use within the 3 percent
4 Increasing demand and unreliable supply Increasing population and water demandThe expected population growth is about 2.6 billion in next 45 years, and it would mostly be from developing countries according to the U.S. Census Bureau.Unreliable supplyDue to the climate change and pollution, traditional method of collecting water is becoming unreliable.Ex- Australia, a country relied on collecting rain fall water is now looking for alternatives such as desalination due to the drought and low rain fallEx- Southern California dependence of Colorado river.
5 Christopher Gasson of Global Water Intelligence (GWI) “People do desalination when they run out of opportunities, and the problem is the world overall is running out of opportunities: groundwater is overexploited to the extent it’s becoming saline and unusable; rivers are being drained; new dams are becoming less and less viable [and] long-distance transfer is expensive and controversial.”
6 What is Desalination?Desalination is the process of removing dissolved salt and other minerals from seawater to create freshwaterThe fact that desalination requires sea water the construction of a plant is limited by locationMajority of desalination plants are operating and being built in middle eastern country and Pacific island
7 General Process diagram of Desalination Pant Water feedPre treatmentDesalination UnitPost treatmentFresh waterbrineFiltering Large particlesScreeningFloatationSedimentationcoagulationChlorinationUV treatmentpH adjustmentCO2 absorptionLimestone (CaCO3)pH adjustmentChlorinationRe-mineralization
8 Varying post treatment according to application Drinking waterIrrigation waterProcess waterSodium chloride< 450 mg/LSAR optimizationminimizedCalcium, MagnesiumHardness 6-10oDpHBoron<0.5 mg/L (WHO) <1 mg/L (EU)Crop dependentDisinfectionRequiredNot required
9 Different Types of desalination technology Thermal desalinationMulti-stage flash (MSF)Multiple-effect distillation (MED)vapor-compression (VC)Membrane desalinationReverse Osmosis (RO)Electro dialysis reversal (EDR)Nano filtrationMembrane distillationOthers include Solar , and Geothermal desalination
10 Thermal desalination (Conventional) Usually requires large amount of energyGood combination with Power plant (Dual purpose)Thermal Desalination plant can use thermal energy (Low grade energy) that has been exhausted from the power plant.For MSF distillation process distillers are coupled with extraction condensing or back pressure steam turbineMost of the desalination plant in middle eastern is dual purpose desalination plant to achieve low operating cost.
13 Membrane desalination Semi permeable membrane is used for processing waterRelatively lower energy consumption of Energy compared to thermal desalinationDriving force is supplied by a pump (Electricity)Typical operating pressure of sea water reverse osmosis is 600~1000 psiTypical operating pressure of brackish water is psi
14 Reverse Osmosis Osmosis Reverse Osmosis What are the dependencies that affect the timeline, cost, and output of this project?
17 World largest RO desalination plant in Saudi Arabia
18 Trend of desalination Plant Membrane desalination is being favored over thermal desalinationDevelopment of membrane technologyIncreased durability of membraneDuring 1980 and 1990 the life time of membrane was 2~3 y; life time of membrane these days are 7~7.5 yCapacity of processing water per membraneIncreased efficiency of membraneTypical efficiency of a membrane is reported to be 48%Reduced cost of membrane production
20 Economic side of desalinated of water Typical cost of desalinated water (1 m3 =264 gallon)sea water desalting US $ /m3brackish water desalting US $ / m3Cost of traditional supply of waterUS $ /m3Desalinated water cost componentcapital costs (%)energy costs (%) other costs(labor, chemicals, etc) (%)Depending on the location desalinated water can be competitive with other sources of water
22 Comparison of the two type MSF desalinationBenefits:low operating cost when it is co-located with power plantRelatively low quality of feed water compared to RO.Cons:High operating cost when sources of heat is not availableHigh rates of corrosion and scale formationRO desalinationBenefits:Low energy intense(Reduced energy consumption)High quality process waterCompact plant designCons:Higher capital costRe-mineralization is neededComparison in terms of energy usageAverage thermal desalination produce 23.41kgCO2/m3Average reverse osmosis would produce 1.78kgCO2/m3
23 Issues and Misconception of Desalination Major concerns:Effects of open water intake to marine lifeFish eggsFish larvaePlanktonPollution due to the brineHighly concentrated brine water is denser than sea waterIncrease in CO2 emissionDuplicate this slide as necessary if there is more than one issue.This and related slides can be moved to the appendix or hidden if necessary.
24 Efforts in conserving environment Redesigning intake pipe and discharge pipeOffshore intakeSub sea bed intakePassive intakesUse of an alternative energy sources for desalination plantMajority of the desalination plant in Australia is Wind poweredSaudi Arabia, a world’s largest producing country is investigating use of solar powered desalination plant.More energy efficient designCombining technology's of both thermal and MembraneOutfall pipeMulti port diffusorBlending with cooling tower water
25 Growing industryAs of year 2007, approximately 7,500 desalination plants are operating world wide.60 % of the plants are located in Middle EastDesalination industry is growing 10 to 15 % on average per year