Pretreatment Improvement for Membrane and Thermal Desalination Systems

Transcription

1 Goals for Seawater Intake, Outfall and Pretreatment Improvement for Membrane and Thermal Desalination Systems CENTER OF EXCELLENCE FOR SEAWATER DESALINATION TECHNOLOGIES

2 OVERVIEW 1. Seawater System Classification 2. General Engineering Methodology 3. Hydraulic Problems and Solutions 4. Typical Intake Layouts 5. Goals

3 1. Seawater System Classification Seawater Supply Pretreatment and Pumping Return Pumping Cooling Water and/or Brine Return Desal. PLANT (SW Consumer) Open Channel Buried Pipes/Culverts Tunnel Combinations of above Beach Well None (direct intake) Open Pit/ wet Well Closed Piping Combinations of above Screening Filtration Both in Combination Open Pit/ wet Well Closed Piping Combinations None (gravity flow) Open Channel Buried Pipes/Culverts Tunnel Combinations of above None (direct outfall)

4 2. General Engineering Methodology Layout and Construction Location INTERRELATED Risk Assessment and Control Seawater Intake and Outfall Tender Requirements ITEMS REQUIRE ENGINEERING ITERATION PROCESS! Costs Process

5 2. General Engineering Methodology Climate (Seawater and Air Temperatures, Rainfall, Wind, Ice) Seismic Activity Water Quality (Suspended Solids, Chemical Composition and Properties) Tide Levels Soil Conditions Bathymetry Environmental Regulations (Marine Life, Chemical Properties of Discharges, Noise) Neighborhood (Other SW Consumers, Industrial Area, nearby Villages) Marine Recirculation (Wind, Tidal Currents, Location of Intake/Outfall Points, etc. Oil Spill Warning and Protection System Fish Protection System Sedimentation System Seawater Pre-Treatment (Chlorination, Screening, Filtering) Seawater Pumping (Flow, Pressure, NPSH, Approach Flow Conditions, Hydraulic Transients) Constructability t (Weather, Waves, Soil, Water Depth, Size and Type of Structures) t Redundancy and Availability Effects during Construction (e.g. suspended solids) Other Main and Auxiliary Equipment (Crane, Ventilation, I&C, etc.) Material Selection and Corrosion Protection Time Schedule (Construction Time, Equipment Delivery Time) Damages during Construction (Experience of (Sub-) Contractor, Inherent Safe Design) Damages during Operation (e.g. Ship Traffic, Wave Action) Protection against un-authorized Access

6 2. General Engineering Methodology COSTS CAPEX Analysis of Capital Expenditures OPEX Analysis of Operational Expenditures (over Plant Life Time, Contract Duration) Analysis of PLANT LIFE CYCLE COSTS on a case by case basis

7 3. Hydraulic Problems and Solutions Pump Approach Flow Problems

8 3. Hydraulic Problems and Solutions Flow Optimization Through Physical Hydraulic Model Tests

9 3. Hydraulic Problems and Solutions Sink and Sunk Effects Transient Flow Conditions, Up- and Down-Surge Issue in systems with long offshore pipes or culverts and with pumps located onshore Severe flooding possible after emergency shut down of pumps Potential dry running of pumps during pump start-up phase To be carefully analysed in design phase in order not to render pump station operation impossible

10 3. Hydraulic Problems and Solutions

11 4. Typical Intake Layouts Travelling Band Screen Installation Drum Screen Installation Seawater Screening and Pumping Plants for Medium to Large Scale Installations

12 4. Typical Intake Layouts Pipe floated in and sunk on Seabed Pipe laid by Horizontal Directional Drilling Method Seawater Intake Arrangement for Small to Medium Scale Installations

13 4. Typical Intake Layouts Seawater Intake Arrangement with Integrated Air Backwash Filters

14 5. Goals Investment cost reduction Operational cost reduction No maintenance for offshore work for e.g. 20 years Minimizing environmental impacts Increase in availability to 99% Optimization of pumping power Optimum solution for each individual location and project required (considering pollution, algae, seaweed, mussels, oil, wastewater contamination, etc.)