1 -
Hvor står afsaltning energimæssigt?
Chefingeniør Christian Stamer
Krüger A/S
DWF temamøde Vand og energi-effektivisering
torsdag den 28. april
Energi til afsaltning omfatter i bredere forstand både anlæg og
drift. Vi behøver en fælles standard for at kunne sammenfatte
det totale energikoncept.
I Veolia har vi valgt at benytte begrebet Carbon Footprint, som
udtrykker den ækvivalente mængde CO2, som aktiviteten
belaster kloden med set over en lang årrække.
Veolia har udviklet et særligt værktøj til dette formål, som jeg
vil anvende i det følgende.
2 -
3 -
Which tools to calculate the Carbon Footprint?
Computes the GHG emissions based on basic process models
Excel spreadsheet dedicated to Carbon Footprint
Other impact indicators
Human Health (human toxicity, respiratory effect…)
Biodiversity (aquatic and terrestrial ecotoxicity…)
Resource depletion (e.g. « water footprint » under development)
Ai * EFi
i1
n
Emissions Factor (in kg.CO2eq per)
Activity Data (tons of steel, KWh elec…)
Perimeter (construction, operation, decommissioning)
Carbon Footprint =
Ai * EFi
i1
n
Emissions Factor (in kg.CO2eq per)Emissions Factor (in kg.CO2eq per)Emissions Factor (in kg.CO2eq per)
Activity Data (tons of steel, KWh elec…)
Perimeter (construction, operation, decommissioning)Perimeter (construction, operation, decommissioning)Perimeter (construction, operation, decommissioning)
Carbon Footprint =
Gas GWP over 100 years
(CO2eq)
Carbon dioxide (CO2) 1
Methane (CH4) 25
Nitrous oxide (N2O) 298
Hydrofluorocarbons 12 to 12,000
Perfluorocarbons 5,700 to 11,900
Chlorofluorocarbons 4,600 to 14,000
Conversion factor: Global Warming Potential (GWP) over 100 years
One single unit, ton CO2eq,
reflecting the impacts of all GHG
4 -
Life Cycle Inventory
How to assess the Carbon Footprint ?
Decommissioning
Production
of concrete
Construction
Operation
Intake pumping
Water treatment
Water distribution
Inventory of
intermediates
INPUT FLOWS
Fossil fuels
Minerals
OUTPUT FLOWS
Indirect GHG
Emissions
Production
of chemicals
Production
of electricity
Background processes
LCA scope
Ecoinvent database For Emission Factor
Technical modeling
of process units
Raw water
Potable water
Direct GHG
emissions
Plant perimeter
5 -
Emission Factors
Construction
Concrete: 260 kg.eq CO2/ m3
Steel: 2770 kg.eq CO2/ t
Power – impact of local energy mix
Operation
FeCl3 40%: 719 kg.eq CO2/ t
Ca(OH)2: 750 kg.eq CO2/ t
NaOCl 15%: 813 kg.eq CO2/ t
Polymer: 1.57 kg.eq CO2/kg
France: 0.09 kgCO2/kWh
Spain: 0.35 kgCO2/kWh
Saudi : 0.75 kgCO2/kWh
Australia: 0.92 kgCO2/kWh
6 -
SWRO desalination plant
0
0,5
1
1,5
2
2,5
3Membrane renewal
Plant and piping network construction
Disinfectant NaOCl production
Remineralization chemicals production
CIP chemicals production
Antiscalant production
Coagulant / Flocculent production
Electricity production for water treatment
Electricity production for intake and distribution
Green House Gases emissions
in kg CO2-eq/m3
of potable water
Construction < 2% of GHG emissions
RO pumping needs > 75% of GHG emissions
7 -
Impact of local energy mix
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5UAE grid mix
Saudi Arabia grid mix
Australian grid mix
Spanish grid mix
Nuclear thermal plant
Wind turbine
Photovoltaic cells
Combined cycle gas turbine
Oil fired plant
Coal thermal plant
GHG emissions in kg CO2-eq/m3 of potable water Power supply
UAE grid mix: 99% gas turbines, 1% oil fired plants Saudi Arabia grid mix: 47% gas turbines, 53% oil fired plants Australian mix: 75% coal, 20% gas, 5% hydro/wind Spanish grid mix: 22% coal, 30% gas turbines,
20% nuclear electricity, 18% hydro / wind
Australian
model
But, energy mix is not within the scope of the suppliers of water
technology
Need to look at the C footprint of the water treatment schemes
8 -
Greenhouse Gaseous emissions in kg CO2 eq/m3
for desalination plants
0
0,5
1
1,5
2
2,5
3
3,5
4
FUJAIRAH OMAN SUR SYDNEY
Projects
kg
CO
2 e
q/
m3
po
tab
le w
ate
r
Membrane renewal
Plant and piping network construction
Sodium hypochlorite / sodium bisulfiteproduction
Sulfuric acid, sodium hydroxide, CO2production
Antiscalant and cleaning chemicalsproduction
Coagulant and polymer production
Electricity production
Results from Eolia TM
February 2009
François Vince
3.78 kWh/m3 @
39 g/L TDS 28°C
3.84 kWh/m3
average per year
3.92 kWh/m3
average per year
Energy mix:
98% gas
2% oil
Energy mix:
82% gas
18% oil
Energy mix:
79% coal
12.14% gas
6.36% hydro
9 -
Salinity/ temperature impact on 1st pass RO pressure Pressure 1 st Pass
min 58 bars
max 64,5 bars
50,0
55,0
60,0
65,0
70,0
75,0
80,0
15 20 25 30 35 40 45
Temperature
Pre
ss
ure
38
39
40
41
42
45
50
55
TDS g/l
28
Gap: 6,5 bars
32
Case Study: Oman
10 -
Concentrate
Reverse
osmosis
Booster
Permeate
Post
treatment
Drinking
Water Pretreatment
Intake
Seawater
ERD
Variable
frequency drive
HP pump
Where is the electricity consumption the highest: 1st pass
Variable Frequency Drive on RO booster pumps allows
flexibility to adapt to pressure variations
Case Study: Oman
11 -
Electrical consumption Breakdown on RO 1st pass
0,00
0,50
1,00
1,50
2,00
2,50
1 -HP RO Booster pumps 2 -DWEER Booster pumps 4-1st PASS HP pumps 5-Recirculation pump for DWEER
type of pump
kw
h/m
3
Kg
CO
2 e
q/ m
3
0.46
0.92
1.38
1.84
2.3
0
Case Study: Oman
HP RO Booster DWEER Booster HP Pump DWEER Recirculation
Emission factor at Oman: 0.92 kg CO2eq/ kwh
DWEER =
Dual Work Exchanger Energy Recovery
12 -
Example at Oman Sur : up to 76.5% of electrical consumption on the
first pass
Electrical consumption Breakdown on Oman Sur
1 -HP RO Booster pumps
2 -DWEER Booster pumps
4-1st PASS HP pumps
5-Recirculation pump for DWEER
6-Second pass RO pumps
7-Intake pumps
10-Existing plant
11-Others
1st pass RO 67-76,5%
Pretreatment 5%
Where is the electricity consumption the highest?
Case Study: Oman
13 -
HYDRANAUTICS DOW
1st PASS
Pressure at maxi conditions - worst case
(TDS max / T°C min - 4,5 years) 60,0 62,5
Boron in permeate 1st pass - worst case
(4,5years - 35°C) 3,23 2,01
2nd PASS
Pressure at maxi conditions
(TDS max / T°C min - 4,5 years) 12,0 10,2
Feed pH max 10,4 10,2
Boron in permeate 2nd pass - worst case
(4,5years - 35°C) 0,37 0,39
Impact of the choice of membrane on electrical consumption
14 -
Impact of Energy Recovery Device
Pelton Turbine: 80% DWEER - ERI: 95%
0
0,5
1
1,5
2
2,5
3
3,5
Power Consumption (kWh/m3) Carbon Footprint (kCO2eq/m3)
kW
h/m
3 -
kg
CO
eq
/m3
DWEER - ERI - 95%
Pelton - 80%
15 -
CONCLUSIONS
Tools available:
Compare water supply scenarios and main process trains
Excel spreadsheet to get into more details in the calculation
Carbon footprint of SWRO plants: 80-90% from energy
consumption
How can we reduce the Carbon footprint
Use the most efficient ERD – optimal pump
Find new membrane system configurations
Use the most energy-efficient membranes => e.g. NanoH2O
Desalination systems powered by renewable energies
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