Sea Water & Brackish Water Reverse Osmosis System

Transcription

1 Sea Water & Brackish Water Reverse Osmosis System

2 Technology for Sea Water Desalination Process & Maintenance Reliability Costs- CAPEX & OPEX Product Recovery THERMAL (MSF) Simple Pretreatment Product quality: TDS = 5~25 ppm Medium maintenance (Potential problem: scaling & corrosion) Feed quality flexible High installation cost Typical production cost (1.71 USD/m 3 ) Low conversion (10 ~ 20 % recovery) MEMBRANE (REVERSE OSMOSIS) Complex Pretreatment Product quality: o 1 st stage RO: TDS max. 400 ppm o 2 nd stage RO: TDS max. 15 ppm High maintenance (Potential problem: cleaning/replace membrane) Feed quality fixed Lower installation cost Typical production cost (1.01 USD/m 3 ) Medium conversion (30 ~ 45 % recovery)

3 Desalination Advantages- Reverse Osmosis Technology Desalination is a process that involves reduction of salt from sea water using membranes by applying external energy in order to be used as fresh water. Desalination using Seawater Reverse Osmosis technology when compared to thermal technologies is widely accepted and popular due to certain significant factors such as: Efficiency in producing higher volume of output water Lower Energy Consumption High modular and scalable in plant configuration Lower capital and operating cost

4 Integration of Technology Water Technologies Made Simple Sea Water Open Intake/ Beachwell MATTEN s Water Treatment Systems Commercial & Industrial Use

5 Simplified Project PFD Feed Sea Water Pretreatment TDS = ppm 1 st Stage 2 nd Stage SWRO TDS = 500 ppm BWRO To Polisher TDS = <20 ppm Brine Recovery Unit SWRO adalah ±36% (1 st stage = 45%, 2 nd stage = 80%).

6 Sea Water Intake Systems Beach wells are usually located on the seashore in close vicinity to the ocean. These intake facilities are relatively simple to build and the seawater they collect is pretreated via slow filtration through the subsurface sand/seabed formations in the area of source water extraction. Raw seawater collected using beach wells is often of better quality in terms of solids, silt, oil and grease, natural organic contamination and aquatic microorganisms, compared to open seawater intakes. Sometimes, beach intakes may also yield source water of lower salinity.

7 Sea Water Intake Systems Open intake for large seawater desalination plants are typically complex facilities, including intake piping that extends several hundred to several thousand metres into the ocean. Source water collected through open intakes usually requires pretreatment prior to reverse osmosis desalination. New open ocean intakes could potentially entrain more aquatic organisms than beach wells because they take raw seawater directly from the ocean rather than source water pre-filtered through coastal sand formations.

8 Process Design Pre-treatment & Chemical Dosage The raw seawater is supplied to an appropriate pre-treatment system by RO feed pump. In order to facilitate a good SDI reduction, strong anti-microbial agent and a coagulant will be dosed upstream. Ferric Chloride (FeCl 3 )- will destabilize the suspended solids rapidly and increases the removal efficiency of Dual media filtration Sodium Hypochlorite (NaOCl)- will cease the growth of microorganism on the inner pipe walls

9 Process Design Pre-treatment & Chemical Dosage The pretreatment system will depend on the seawater quality. Common pretreatment system : - Multimedia Fitration - Dissolved Air Floatation + Multimedia Filtration - Clarifier + Multimedia Filtration - Ultrafiltration Membrane System

10 Process Design Pre-treatment & Chemical Dosage

11 Process Design Pre-treatment & Chemical Dosage Important parameter on the pretreatment : SDI (Silt Density Index) Suspended solids and colloidal materials in feed water are one of the biggest problems in reverse osmosis systems. Even though most systems have some pretreatment including 5 micron prefilters, these fine particles are responsible for fouling of reverse osmosis membranes. An SDI of less than 5 is considered acceptable for the reverse osmosis systems. This means that at values of SDI of less than 5, the membranes should foul at a very low rate.

12 Process Design Sea Water Reverse Osmosis Main Components : - Feedwater Pump - Cartridge Filter - High Pressure Pump, Duplex Energy Recovery Device : Turbo or Pressure Exchanger - SWRO Membrane & Housing - Piping Duplex 2205, Instrumentation & Control

13 Process Design RO Operation RO separation is a pressure driven process, being said that the external pressure shall be provided by RO high pressure pump. The pressure transmitters are located at critical upstream and downstream points of the pump to constantly monitor the pressure and send back the real time data to the data logging unit. The pressurized water will flow through spirally wound RO membranes, the place of actual separation process. An online conductivity transmitter will be used to monitor the conductivity of permeate and offspec, as the latter being a water with higher conductivity than a specified range.

14 Process Design RO Operation

15 SEA WATER REVERSE OSMOSIS PROJECT REFERENCE Project Name : Sea Water Reverse Osmosis 4 x 20 m3/hour End User : CNOOC SES Ltd. Location : Pabelokan Island

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17 5. Sea Water RO 6. Brackish Water RO

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21 THANK YOU