Design, Modeling and Simulation of Seawater RO Desalination Plant ENGINEERING UAEU Design, Modeling and Simulation of Seawater RO Desalination Plant Presented by Haleimah Mohamed 199903922 Tamadher Ali Mohamed 199902261 Reem Khalifa 199902241 Fatima Al-Zarouni 199903949 Under the supervision of Dr. Mohamed Abdulkarim

Anti-scalant addition Neutralization pH adjustment Process flow Diagram HCl Al2(SO4)3.14.3H2O SBS Disinfection pH adjustment Anti-scalant addition Media Filter Coagulation unit Cartridge Filter (Chlorination) De-Chlorination unit Neutralization pH adjustment Storage Tank RO Membrane NaOCl Hypersperse AS110 HPP NaOH Pump

Material Balance - Media Filter Used to prevent reverse osmosis membrane from fouling by removing large percentage of suspended solid from feed water SDI measurement commonly used to indicate the effectiveness of media filter Almost, all RO membrane manufacture recommends SDI to be less than 3

Material Balance - Antiscalant [Ksp] = 2.44 x10-5 1.05 x10-4 93.176 L/day [Ca+2] x [SO4-2]= 4.23 x 10-4 mol/L Ksp= 2.44 x 10-5 The equation of calulating the dose rate Antiscalant (Hypersperse AS110)

Material Balance - Cartridge filter Plant SDI before cartridge SDI after cartridge Al Jubail, Saudi Arabia RO desalination plant 3 2.8 Singapore pilot plant 6.5 6.1 desalination plant at Larnaca, Cyprus

Material Balance - Cartridge filter

Material Balance - Dechlorination Normally, the available free chlorine concentration before RO membrane is 0.5 – 1 ppm. The maximum allowable chlorine concentration before RO membrane is 0.05 ppm. Residual free chlorine can be removed by: adsorption onto activated carbon media filter chemical reducing agent (SBS)

- Dechlorination Chemical Material Balance - Dechlorination Chemical Sodium Bisulfite can be formed by dissolving Sodium Metabisulfite (SMBS) in water In theory, 1.34 mg of SMBS will remove 1 mg of free chlorine. In practice, designers used to add 3 mg/L of SMBS of chlorine Total amount of free chlorine in water = 503 * 106 mg /day

- Dechlorination Chemical Material Balance - Dechlorination Chemical SMBS H2O SBS The amount of SMBS needed to remove free chlorine = 7968.22 mole/day The amount of moles of Sodium Bisulfite needed to remove the free chlorine = 15,936.13 mole/day The dosage rate of SBS needed to remove residual chlorine = 205.58 gal/day

Material Balance RO membrane - RO membrane Q6 Stage 1 Stage 2 Q1 Q2 Q4

Material Balance - RO membrane Parameters Value Overall Recovery% 30% Recovery for second stage 85% Salt rejection % 95% Total product 40MGD Total dissolved solid for total product 170 ppm Total dissolved solid for feed 43153ppm

Material Balance - RO membrane Q6 Q1 Q2 Q4 Q5 Q3 Q2 =47 MGD TDS2 = 2156.79 ppm

Material Balance - RO membrane Q6 Q1 Q2 Q4 Q5 Q3 Material balance on second stage: TDS5 =13415 ppm Q6 Q1 Q2 Q4 Q5 Q3 Material balance on first stage: The overall salt balance for the system TDS6= 61550.46 ppm

Material Balance - NaOH Added for pH adjustment to minimize the corrosion in the product water pipes The required pH for drinking and potable water is in the range of 6.5 – 9.5 The calculation was based on Neutralization of acid Adjust pH from 7 to 8

Design - Cartridge filter Feed flow rate = 349 x 103 L/min Capacity of each filter = 600L/min feed water flow rate / filter capacity = Number of filter element number of filter = 582 filter Number of vessel = 25 ( 23 in operate + 2 standby) Filter cartridge/ vessel = 26 ΔP = 4 psi per 1 m3/min The feed flowrate inter each vessel= 15 m3/min Total ΔP = 15 x 4 = 60 psi = 4 bar

Design - Ultrafiltration number of module = module

Design - Ultrafiltration number of configuration = 203 configuration

Design ions C (mg/l) C (mol/L) Mg+2 829.35 0.03412 Ca+2 488 0.0122 Na+ - RO membrane ions C (mg/l) C (mol/L) Mg+2 829.35 0.03412 Ca+2 488 0.0122 Na+ 13160.22 0.572 HCO3_ 115.9 0.0019 SO4-2 3473 0.03617 Cl- 23811 0.6726

Design - RO membrane For feed

Design properties Stage #1 Stage#2 47 MGD 40 MGD 2755 L/h 2690 2290 - RO membrane properties Stage #1 Stage#2 Permeate flow 47 MGD 40 MGD Qper,vessel 2755 L/h # of vessels 2690 2290 # of element 16140 13740

Design - RO membrane Feed Permeate One vessels

Design - RO membrane The calculations of pressure drop in RO membrane

Environmental Impact Products Chemicals Sodium Hypochlorite Antiscalent Hydrochloric acid (HCL) Sodium bio-sulphate Coagulant (Aluminum sulphate) NaOH 2. Process MMF Membrane Desalination plant Intake Products Brine

Actions Advantage: Disadvantages: Sand filter Chemicals Process Sand work as a filter Disadvantages: Need higher pressure Limits on flow rate Cost

Actions 3. Products Mix brine with seawater before discharge. RO plant Feed seawater To seawater Mix brine with seawater before discharge. 2) More than one discharge. These are located a way of each other at a distance. 3) Mixing brine water with cooling water coming from adjacent power plant. 4) Evaporation ponds 5) Deep well disposal

HAZOP Analysis PID Before HAZOP

HAZOP Analysis HAZOP analysis on water feed entering multi media filter. (Line no. 2) Guide Word Deviation Causes Consequences & Action NO FLOW Pump failure Ruptured (broken) pipe Valve (V2) shut No product Check valve Check & Repair pump and pipe Put flow indicator (FI 2) LESS Pipe leakage Low production quality Less feed pressure Slow operation MORE Damage pump The multi media will be shutdown. The ratio between feed water and coagulant is not the same Need to fix coagulant dosing The efficiency of media filter will decrease. The suspended solid will not be removed Lower the product quality Over flow Lower removal capacity Check & Repair V2

PID After Hazop

Modeling and Simulation - Reference Process

Any Question??