tripartite meeting, oct. 2010 1 a new concept for resolving the ballast water management problem -...
TRANSCRIPT
Tripartite Meeting, Oct. 2010
1
A New Concept for Resolving the Ballast Water Management Problem
- Buoyancy-control Type Ballast-free Ship -
Makoto Arai Dept. of Systems Design for Ocean-Space, Faculty of Engineering
Yokohama National University, Japan
Tripartite Meeting, Oct. 2010
2
・ Ballast water problemsLoading and discharging operation,Impacts,
Ballast water convention,
Ballast water treatment technologies
・ Proposed ballast-free ship concept
・ Model experiments and Numerical analyses
・ Application to actual ship tank configurations
・ Conclusions
3-D numerical analyses
Model experiments
Tripartite Meeting, Oct. 2010
3Http://www.globallast.od.ua/eng/problem.asp
Loading and discharging operation of ballast water
Ballast water problems
Ecological: native biodiversity and/or ecological processes are disruptedEconomical: fisheries, coastal industry and other commercial activities and resources are disruptedHuman health: toxic organisms, diseases and pathogens are introduced
GreenTech
3
Http://www.globallast.od.ua/eng/problem.asp
Loading and discharging operation of ballast water
Dischargingcargo
Loading ballast water
Cargo holdempty
Loading cargo
Ballast tanks full Discharging ballast water Ballast tanks empty
Cargo holdfull
(1) At source port (2) During voyage (3) At destination port (4) During voyage
Ballast water problems
Possible impacts
Tripartite Meeting, Oct. 2010
4
http://www.globallast.od.ua/eng/problem.asp
Tripartite Meeting, Oct. 2010
5
Organism category Regulation
Plankton, 50 μm in minimum dimension <10 cells/m3
Plankton, 10-50 μm <10 cells/ml
Toxicogenic Vibrio cholera (O1 and O139) <1 cfu*/ 100ml
Escherichia coli <250 cfu* / 100ml
Intestinal Enterococci <100 cfu* / 100ml
Planktons gathered by a plankton net.(Ohmura, Fukuyo: NTS, Sept. 2008)
D-2 Regulation : Ballast water performance standard
Mainly animal plankton
Mainly plant plankton
*colony forming unit: measure of viable bacteria numbers
Ballast water management conventionThe International Maritime Organization (IMO) adopted the “International Convention for the Control and Management of Ships’ Ballast Water and Sediments” in 2004.
Tripartite Meeting, Oct. 2010
6
Ballast water treatment technology process options
[Ref.] Lloyd’s Register, Ballast water treatment technology - Current status, 2007
・ Surface filtration
・ Hydrocyclone
Treatment:
・ Coagulation/ Flocculation
Chemical enhancement:
・ Chlorine dioxide
・ Vitamin K
・ Peracetic acid
・ Ozonation
・ Electrochlorination or electrolysis
・ Chlorination
Chemical treatment:
・ Cavitation
・ Ultrasonic treatment
・ Gas injection
・ Deoxygenation
・ UV + TiO2
・ UV irradiation
Physical treatment:
・ Cavitation
・ Ultrasonic treatment
Physicalenhancement:
・ Chemical reduction (sulphite/bisulphite)
Residual control:
Physical solid-liquid separation
Disinfection
OR
Tripartite Meeting, Oct. 2010
7
In case of 220,000DWT Bulk carrierSystem-A: Initial cost $4,200,000 Running cost $26,000/treatmentSystem-B: Initial cost $900,000 Running cost $19,000/treatment + overhaul $15,000/year
Example of the arrangement of a ballast water treatment system for a container ship( Ninokura, S., NTS, Sept. 2008)
A trial calculation:
Possible engineering problems:Decrease of cargo space,Increase of the electric generator capacity,Storage of chemicals, sediment,..Maintenance of filters, …Reliability of the complicated system,Supply of expendables,…
Ballast water treatment system
Tripartite Meeting, Oct. 2010
8
Volume of ballast water
Plankton, 50 μm : <10 cells/m3
Plankton, 10-50 μm: <10 cells/ml
D-2 standard:
Acceptable?
VLCC
VLCC with 110,000m3 ballast water:
9cells/m3 x 110,000m3=1x106 cells
9cells/ml x 110,000m3=1x1012 cells
Lpp[m] GT[t] Ballast[ ]㎥
278 85,663 57,195
216 36,074 21,986
181 27,011 14,124
150 13,403 6,274
107 5,997 2,510
Bulk carrier
Lpp[m] GT[t] Ballast[㎥]
322 149,896 110,242
235 52,484 37,601
161 22,943 14,240
145 12,811 8,325
110 6,253 3,316
Oil tanker
Lpp[m] GT[t] Ballast[㎥]
283 58,531 14,895
181 18,502 7,268
150 13,448 6,165
136 11,810 3,165
110 6,543 3,064
Container ship
Lpp[m] GT[t] Ballast[㎥]
152 14,499 6,478
122.9 9,235 2,639
107 6,079 2,981
93 4,724 1,583
70.5 498 776
Cargo ship
Tripartite Meeting, Oct. 2010
9
Is retrofit possible?
An existing shipA newly-built ship
http://www.jasnet.or.jp
Tripartite Meeting, Oct. 2010
10
Summary
1. In order to fulfill the requirements of IMO’s Ballast Water Convention, lots of works, especially the development of BW treatment systems are being
carried out.
2. However, there are a wide variety of ship types with different size, age, shape, cargo type, operation system, etc., and one and only BW treatment system
may not cover all of those ship types. Therefore, we believe it is worth studying the possibility of alternative systems in addition to the BW treatment system.
Tripartite Meeting, Oct. 2010
11
-In the lightweight condition, sea water is drawn into a buoyancy control tank by using the pump system. As a result of the weight of the water taken into the tank, the ship loses some of its buoyancy and gains sufficient draft for navigation. The sea water in the tank is circulated by utilizing the advance speed of the ship. In order to accelerate the circulation of the water in the tank, the shapes of the sea water intake and exit vents are designed appropriately. Also, the locations of the intake and exit are determined considering the pressure distribution on the ship’s bottom. Through the circulation of the water, the components of the water inside the tank are kept identical to those of the local sea water outside the ship’s hull. Together with the opening and closing operation of the air drain system, the tank can be fully filled with sea water even if the tank’s top ceiling is located above the ship’s draft line.
- In the full load condition, the intake and exit vents of the tank are closed, and the tank is emptied by the ship’s pump system to give sufficient buoyancy to the ship.
Concept
Buoyancy control tank
Ship’ advance speed
10
Buoyancy control tankBuoyancy control tank
Air pipe: open
Intake & exit vents: closed
11
Buoyancy control tankBuoyancy control tank
Air pipe: closed
Intake & exit vents: open
Tripartite Meeting, Oct. 2010
12
Intake and exit shapes
Bottom plate
Flow direction
Possible variants of intake and exit shapes
High pressure
Low pressure
30deg.
0.5m
0.5m
Flow direction
30deg.
1mIN-1
IN-2
IN-3
IN-4
1m
1m
1m
30deg.
1m
0.5m
0.5m
0.5m1m
1m
1m
EX-1
EX-2
EX-3
EX-4
Flow direction
Intake Exit
Inside the buoyancy control tank
Outside the ship
Tripartite Meeting, Oct. 2010
13
Fluid A Fluid A
Fluid B
Intake Exit
Before opening the intake and exit After opening the intake and exit
Water locality ratio
Flow
In order to examine the performance of the water circulation, we compared the water locality ratio (R) of each tank. R=(Volume of fluid A in the tank)/(Tank volume)R is defined as the ratio of exchanged fluid volume inside the tank.
In this system a higher water locality ratio is desirable. I.e., R=1.0 (100%) Composition of the seawater inside the tank is the same as that outside it.
Numerical analysesIn this study, we analysed the seawater circulation in the tank by using ANSYS-FLOTRAN.
Tripartite Meeting, Oct. 2010
14
500
240
125
Intake A
Exit C
Exit B
VTR camera
Model experiments at the circulating water channel
Model experiment setup
Model tank
2,026mm
Model tank Dummy bowDummy stern
Flow direction
Tripartite Meeting, Oct. 2010
15
A small amount of colourant was added to the water inside the tank, and the change of colour density in time was measured.
Measurement of the water locality ratio(high speed playback: 8x)
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200 250
数値計算 1.0 m/ s実験 1.0 m/ s数値計算 0.50 m/ s実験 0.50 m/ s
Time (sec.)
Wat
er lo
calit
y ra
tio (%
)
Num. cal.
Exp.
29
IMDC 2009
Measured water locality ratio(L: ship length, U: flow velocity, t: time)
0 10 20 30 40 50 600
10
20
30
40
50
60
70
80
90
100
0.250.51.0
tU/L
U (m/s)
Tripartite Meeting, Oct. 2010
16
Double bottom tankBilge hopper tank
Side tank
Analyses of actual ship tank configurations
Tripartite Meeting, Oct. 2010
17
Double bottom tank of a 1,600TEU container ship (v=23.3 knots)
Intake
300 150
300150
300
300Unit: mm
ExitFlow
T=500s., R=17.3% T=5000s., R=85.5%
0
10
20
30
40
50
60
70
80
90
100
0 1000 2000 3000 4000 5000 6000 7000 8000
海水
置換
率:[
%]
時間t:[s] Time (sec.)
Wat
er lo
calit
y ra
tio (
%)
Computed time change of the water locality ratio (v=23.3kn)
Tripartite Meeting, Oct. 2010
18
Exit: partial sphere type
Intake: flat type
Flow
Intake: flat type with lid
Exit: partial sphere type
Flow
[2000s] 62.5% [4000s] 90.1% [6000s] 97.9%
Original
Modification 2
[6000s] 51.5%
0 50 100%
Flow
[6,000s., 51.5%]
0102030405060708090
100
0 2500 5000 7500 10000 12500 15000 17500 時間: t[s]
海水
置換
率:
[%]
Case 1
Case 2
Case 4
0102030405060708090
100
0 2500 5000 7500 10000 12500 15000 17500 時間: t[s]
海水置換
率:[%]
Case 1Case 2
Case 4
0102030405060708090
100
0 2500 5000 7500 10000 12500 15000 17500 時間: t[s]
海水置換
率:[%]
Case 1Case 2
Case 4
0102030405060708090
100
0 2500 5000 7500 10000 12500 15000 17500 時間: t[s]
海水置
換率
:[%
]
Case 1Case 2Case 4
Modification 2
Modification 1
Original
Modificationof trans.
Intake type
Yes
Yes
No
Flat type with lid
Flat type
Flat type
Tank design
Time (sec.)
Wat
er lo
calit
y ra
tio (
%)
Bilge hopper tank and side tank (1,600TEU container ship, v=23.3knots)
Tripartite Meeting, Oct. 2010
19
Comparison of measured number of organisms in Tokyo Bay and IMO's D-2 standards
< 100 cfu/100ml-Intestinal Enterococci
< 250 cfu/100ml-Escherichia coli
< 1cfu/100ml-Toxicogenic Vibrio cholera (O1 and O139)
< 10 cells/ ml103 cells/ml m in minimum dimension
< 10 cells/m3105 cells/m3 m in minimum dimension
IMO standardsTokyo Bay [Ref.: Kuno]Organism category
Plankton, 50
Plankton, 10-50
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200
99.99% at 154 n.m.99% at 77 n.m.
Wat
er lo
calit
y ra
tio (
%)
Voyage distance (nautical miles)
99.99% dilution
99.0% dilution
Example of the relation between the voyage distance and the sea water locality ratio
Cf. ..200 mnEEZ
Design criterion of the proposed ballast-free ship
Tripartite Meeting, Oct. 2010
20
In this presentation, we proposed a ballast-free ship concept and showed the results of model experiments and numerical analyses carried out to enhance the performance of the proposed system. In order to evaluate the ballast-free system, we proposed a criterion that accords with the IMO’s D-2 regulation. The proposed ballast-free ship can be an efficient and environmentally friendly alternative to cope with the ballast water problems on ships. The system is especially effective for retrofitting since it can be applied to existing ships without serious structural modifications.
Conclusion
Tripartite Meeting, Oct. 2010
21
Upogebia major
As a matter of fact, this technology has been used by somewild animals and crustaceans.
Ventilation inside the nest ofPrairie dogs
We also use this tech!
http://ja.wikipedia.org
Wind