Optimizing Cargo Heating For Tankers - elintconference.gr · Optimizing Cargo Heating For Tankers...

Optimizing Cargo Heating For Tankers

13-12-2017 ELINT Annual Meeting

Vassilios Dimoulas

Hellenic Plan Approval Office Manager

2 Optimizing Cargo Heating for Tankers © - Copyright Bureau Veritas

Facts

► A series of crude oil and fuel oil cargoes require heating during the voyage

► Cargo temperature should not fall below a specific level dependent upon the cargo pour point and cloud point

► Boiler fuel oil consumption for cargo heating during a tanker voyage is a significant figure (e.g. 100 to 200 tons for an Aframax)

► Heating systems are designed according to specific design environmental conditions and requirements for cargo heating up rate

► Significant consumption gains may be realized by applying and following an optimized cargo heating schedule

► Cargo and bunker management heating is part of the IMO Ship Energy Efficiency Management Plan (SEEMP, MEPC.1/Circ.683 and 684)

► Detailed Heating Logs are required to be kept by the crew


Heating practices

Extract of IMO/OCIMF example SEEMP:


The CHS Software tool


The CHS Software tool

Main Features:

Automatic calculation of optimum cargo heating schedule

Vessel Specific

Cargo tanks interact with each other, the adjacent spaces and environment by applying a complete heat transfer model

Effects of change of any of the parameters (environment, cargo type, cargo temperature) to the steam and fuel consumption are observed “on the fly”

Follow up of the actual voyage by entering measured temperature values and readjustment of the heating schedule

Storing and retrieval of previous voyage plans

Visualization of plan by using graphs

Printing of full reports


CHS thermodynamic model

Heat loss (conduction):

Tcargo (P)

Tsea

Tair Tcargo (S)

Tair

Depends on temperature difference, surface area and heat loss coefficient for each surface:

HL = h x S x (T1-T2)



Heating up:

Required Heating rate depends on cargo mass, specific heat constant, temperature temperature difference and target time for heating up:

HR = mc x SH x (T2-T1) / t

T1

T2

t



• Total heating energy is the sum of the energy needed to overcome the losses and provide the required cargo heating up

• Total required steam capacity is calculated using steam enthalpy tables

• Fuel consumption is calculated using boiler consumption curves


CHS Representative screens – Loading condition


Voyage Data Entry:

Cargo tanks interact with each other and the adjacent spaces

Effects of change in parameters are observed “on the fly”

Constant calculation of the total fuel consumption on the top of the page

Simulation of “boiler shut off” by calculation of the daily temperature drop


Automatic Optimum Schedule Tool:

Simply click the “Optimize” button

The software calculates the optimum initial cooling down period in days

Linear increase in temperature is applied thereafter to reach the contracted delivery temperature

Cargo minimum transit temperature is observed


Diagrams:

Diagrams available for each cargo tank or for all tanks weighted average

Optimized schedule is shown in this example


Actual heating log function for voyage reporting:

For each day passed actual measured figures are entered. The day can then be “locked” and optimizing or calculation functions for scheduling applied only to the remaining days of the voyage

Locked Days


Exporting of heating log form in Excel:

Form can be customized to fit company existing forms and practice


Worked example – Suezmax actual 52 day Voyage with 2 cargo grades as reported by Master:

Total Consumption: 627.9 tons

Voy No: 62 Cargo Name: API: 11.3 Pour Point: 48.2 F Page:

API: 10.3 Pour Point: 55.4 F Page:

TOTAL

1P 1S 2P 2S 3P 3S 4P 4S 5P 5S 6P 6S SL-P SL-S AVERAGE

09/06/2015 32 27 127.4 128.1 128.8 127.9 132.6 132.6 127.6 129.2 128.3 132.6 129.7 130.8 128.4 128.8 128.8 130.1 129.45 0 KG

10/06/2015 33 27 125.6 125.5 128.2 127.5 132.6 132.8 127.1 128.1 129.7 130.1 128.4 128.4 126.2 125.2 127 129.6 128.3 0 KG

11/06/2015 33 27 122.4 122.2 127.2 126.9 132.0 131.7 126.2 126.5 129.1 129.8 127.0 127.1 124.3 122.7 124.9 128.7 126.85 0 KG

12/06/2015 33 27 122.0 121.1 132.4 133.3 133.9 134.4 125.6 124.7 133.5 135.1 126.1 125.2 122.2 119.1 123.4 132.1 127.8 0 KG

13/06/2015 31 28 125.8 125.4 130.2 131.0 130.8 131.9 125.2 125.6 131.2 132.6 128.3 127.9 122.0 123.4 125.9 130 128.0 0 KG

14/06/2015 29 26 9.1 128.1 124.3 128.5 129.7 131.8 132.1 125.4 126.6 133.0 134.2 127.8 128.7 121.0 118.8 126.8 131.4 129.5 3KG

15/06/2015 26 28 14.6 123.8 126.1 131.4 132.1 133.3 134.4 124.7 124.2 135.7 134.2 127.6 129.0 134.2 131.2 126.2 133.5 130.5 3.3 KG

16/06/2015 29 28 14.2 125.1 125.6 127.4 127.0 133.9 133.3 125.1 124.9 133.0 132.8 131.9 130.1 128.3 127.0 127.5 131.2 129.6 3.0KG

17/06/2015 28 28 16.3 128.7 128.1 128.7 131.0 134.1 136.8 128.8 129.6 133.2 132.6 131.0 130.3 145.0 143.4 129.8 132.8 131.6 3.4 KG

18/06/2015 29 28 14.1 138.0 133.0 131.7 135.3 137.1 140.9 132.8 132.6 135.7 132.1 133.2 133.9 144.9 142.3 134.0 135.5 134.9 3.2 KG

19/06/2015 30 28 15.7 142.0 134.1 135.3 132.3 138.0 140.9 131.2 132.8 135.3 134.8 133.3 134.6 141.3 140.2 134.6 136.1 135.5 3.4 KG

20/06/2015 30 27 12.7 138.6 132.1 134.4 137.5 137.5 140.9 135.3 133.3 138.4 136.6 135.1 138.2 135.9 135.9 135.5 137.5 136.7 3.5 KG

21/06/2015 30 28 7.6 136.6 135.0 136.0 136.8 135.7 140.0 138.7 136.2 137.8 135.1 136.8 136.9 133.9 133.0 136.7 136.9 136.8 3.5 KG

22/06/2015 30 28 11.1 136.8 137.5 136.4 136.2 136.0 139.6 138.2 137.5 136.4 133.2 136.4 135.5 132.4 133.2 136.8 136.2 136.5 3.5 KG

23/06/2015 30 27 12.6 135.5 136.4 138.4 135.5 138.4 135.7 133.0 139.5 134.1 138.0 134.8 135.5 128.5 132.8 135.7 136.5 136.2 3.5 KG

24/06/2015 28 26 12.5 137.5 137.3 139.5 136.0 136.6 141.6 133.5 136.4 135.0 134.8 134.2 134.2 127.9 130.1 135.3 137.1 136.3 3.5 KG

25/06/2015 26 25 16.1 137.7 137.5 135.3 135.5 134.1 140.5 137.7 139.6 136.6 137.5 135.1 135.1 124.2 127.4 136.8 136.4 136.6 3.1 KG

26/06/2015 26 23 20.7 137.1 137.3 134.4 138.7 137.7 140.9 136.2 142.0 135.1 136.2 133.3 136.6 141.8 139.1 137.0 137.2 137.1 2.9 KG

27/06/2015 22 22 8.8 139.1 138.4 137.5 135.9 138.6 139.1 137.1 136.2 133.0 133.9 134.6 133.3 139.8 138.7 136.2 136.3 136.3 1.9 KG

28/06/2015 22 21 5.6 139.1 138.6 137.3 134.8 136.6 136.8 133.7 136.0 133.7 134.4 134.2 134.6 139.8 138.7 135.9 135.6 135.7 1.6 KG

29/06/2015 21 19 6.4 138.9 138.4 136.2 135.3 134.2 134.4 132.3 135.0 136.0 135.0 134.6 131.9 135.3 135.9 134.9 135.2 135.1 1.6KG

30/06/2015 20 19 7.1 138.6 135.5 135.9 133.3 134.1 136.9 131.5 132.1 130.3 130.3 131.4 131.9 130.5 131.4 133.2 133.4 133.3 1.8KG

01/07/2015 17 17 9.5 136.2 133.9 135.0 132.8 132.6 134.4 130.1 132.6 131.5 131.5 127.9 131.2 126.3 128.8 131.6 132.9 132.4 2 KG

02/07/2015 17 16 14.8 134.8 133.2 131.9 131.5 132.4 130.1 130.8 131.2 131.4 131.5 130.1 130.8 122.7 125.8 131.5 131.4 131.4 2.7 KG

03/07/2015 21 16 17 136.4 134.8 136.9 134.1 132.8 136.8 130.3 132.1 130.3 130.8 130.8 132.6 122.7 120.9 132.4 133.5 133.0 3.0KG

04/07/2015 22 22 18.2 135.1 135.1 136.4 135.5 136.0 134.8 132.1 132.6 132.3 131.7 131.9 134.2 120.0 122.2 133.2 134.2 133.8 2.8 KG

05/07/2015 22 22 13.2 136.2 134.2 136.0 133.2 134.8 135.5 132.3 132.8 132.4 131.9 131.9 135.9 117.5 121.5 133.6 133.7 133.7 3.0KG

06/07/2015 22 21 17.6 136.4 136.8 136.8 135.0 134.2 136.4 134.4 135.0 132.6 131.7 133.3 137.3 136.4 136.8 135.5 134.5 134.9 3.0KG

07/07/2015 16 22 16.5 136.4 136.8 136.8 135.0 134.2 136.4 134.4 135.0 132.6 131.7 133.3 137.3 136.4 136.8 135.5 134.5 134.9 3.1 KG

08/07/2015 19 24 16.6 136.8 136.9 137.3 135.9 135.1 136.2 136.0 136.0 134.6 135.1 133.3 138.2 131.2 133.9 136.1 135.7 135.8 3.0KG

09/07/2015 23 24 11.3 137.3 137.8 137.3 137.7 136.0 138.0 136.9 137.3 135.1 135.5 137.3 138.0 127.9 131.4 137.4 136.5 136.8 2.9 KG

10/07/2015 23 25 10.1 138.2 137.8 137.7 138.0 136.6 139.1 137.5 138.0 136.2 136.8 137.8 137.7 126.1 129.9 137.7 137.2 137.4 2.8 KG

11/07/2015 26 26 12.7 139.6 137.8 138.7 136.2 134.1 140.5 137.7 139.6 137.1 136.6 136.8 138.6 124.3 128.7 138.1 137.1 137.5 3.0KG

12/07/2015 26 27 20.1 139.3 137.8 139.5 135.3 132.8 140.2 139.5 138.9 138.7 138.7 137.5 138.6 144.0 145.4 138.7 137.7 138.1 3.2KG

13/07/2015 27 27 19.4 140.0 140.0 139.5 136.4 134.6 142.9 142.9 142.2 140.9 139.5 139.5 140.4 140.0 137.8 140.7 139.0 139.7 3.4KG

14/07/2015 27 27 18.4 139.1 138.9 142.9 136.8 136.6 148.5 143.4 142.7 143.1 143.2 141.1 141.4 137.8 141.4 141.2 141.8 141.6 3.3KG

15/07/2015 28 29 18.7 144.9 141.6 144.0 136.4 137.3 148.6 144.0 144.1 144.1 142.2 144.3 142.3 133.5 138.6 143.4 142.0 142.6 3.4KG

16/07/2015 27 30 20 144.1 142.2 143.8 140.9 139.6 148.8 144.7 145.0 145.2 144.1 143.2 148.3 141.8 143.4 144.0 143.8 144.2 3.4KG

17/07/2015 30 30 22 148.1 144.5 145.4 144.0 140.2 149.7 148.8 146.8 147.2 145.8 145.2 151.3 142.7 142.3 147.5 145.4 146.3 3.5KG

18/07/2015 28 29 22.1 150.1 147.4 148.1 147.2 141.8 150.8 150.4 146.1 149.9 147.9 147.0 151.7 147.7 148.3 148.8 147.7 148.2 3.7KG

19/07/2015 29 29 20.4 151.5 148.1 148.6 152.1 145.4 151.7 149.7 147.7 150.6 147.9 147.2 151.2 142.0 152.2 149.3 149.3 149.3 3.7KG

20/07/2015 32 30 12.9 151.7 147.7 150.8 152.2 148.5 152.1 151.7 150.6 151.2 150.8 149.9 152.1 147.2 151.0 150.7 150.9 150.8 3.0KG

21/07/2015 33 30 12.7 149.9 147.6 149.5 152.2 150.6 151.5 151.7 151.3 152.1 151.2 150.4 152.6 140.4 147.2 150.7 151.1 150.9 2.5KG

22/07/2015 31 29 12 151.2 150.4 150.1 152.4 150.4 151.7 151.3 151.7 152.1 151.7 151.2 152.4 141.6 145.9 151.3 151.3 151.3 2.8 KG

23/07/2015 33 28 9 149.9 148.6 152.4 153.5 152.1 153.1 153.3 152.1 155.1 153.9 151.7 153.1 148.3 145.4 151.5 153.3 152.6 2.3KG

24/07/2015 36 28 7.2 149.9 149.7 151.7 150.1 150.1 152.6 150.1 150.4 152.2 151.3 150.3 151.2 153.9 151.7 150.3 151.4 151.0 2.1 KG

25/07/2015 35 28 8.4 150.8 149.7 151.7 152.4 152.2 150.8 151.9 151.5 152.4 152.6 150.1 151.2 152.1 148.3 150.8 152.0 151.5 2.2KG

26/07/2015 32 28 7.7 150.6 152.6 149.9 152.2 152.1 149.2 152.6 150.4 151.5 152.8 149.9 151.2 146.8 150.4 151.1 151.2 151.2 2.1 KG

27/07/2015 34 29 8 151.0 151.9 151.5 153.5 151.7 151.5 150.1 150.3 150.3 152.6 149.4 149.2 144.0 145.2 150.1 151.7 151.1 2.2KG

28/07/2015 34 29 11 152.2 152.4 151.7 155.5 153.3 148.5 152.1 150.1 150.4 152.6 149.2 150.4 146.8 148.1 150.9 151.9 151.5 2.2KG

29/07/2015 37 29 3.4 152.1 152.6 151.7 153.1 149.2 152.6 152.1 151.2 150.6 153.9 149.9 150.8 144.1 146.7 151.2 151.8 151.5 0 KG

30/07/2015 36 30 3.8 149.2 151.9 148.8 152.6 148.3 151.3 149.9 150.3 149.9 149.7 149.7 149.9 141.8 142.7 150.0 150.0 150.0 1.9KG

31/07/2015 32 30 8 150.8 150.3 150.3 152.2 149.2 150.8 150.1 150.8 150.4 150.3 149.9 150.1 142.3 140.5 150.0 150.1 150.0 2.8 KG

TOTAL BUNKERS CONSUMED: 627.9 M/T

CARGO TANKS (DEG. C)

1ST GRADE : BACHAQUERO C.O 1W-4W-6W-SLOP S

2ND GRADE: BOSCAN C.O 2W -3W-5W-SLOP P

DATE 1 AVG-2 FSTEAM

PRESS

HFO

CONS

SEA

TEMP

AIR

TEMPAVG-1

F


Heating practice followed was poor with two big heating up periods and constant use of the boiler for most part of the voyage

Simulation in CHS:

Total Consumption:

CHS calc: 628.2 tons

Actual: 627.9 tons

Difference: 0.04%


Alternative option using the automatic CHS “Optimize” function and the same loading and delivery temperatures:

Total Consumption:

CHS optimized: 393.9 tons

Actual: 627.9 tons

Fuel Saving: 37.2% (!)


Comments on worked example and savings:

• Actual practice was poor so there was a lot of room for improvement even

without use of CHS hence the impressive savings figure.

• CHS was able to simulate actual measurements with very high accuracy.

• The schedule proposed by the CHS automatic optimizer algorithm includes a

period of “boiler off” of 43 days and 9 days of heating up. During this procedure

the cargo temperature drops to an average of 35.6°C, while cargo pour point is

9°C.

• If a higher temperature needs to be maintained during voyage CHS will

automatically calculate the day when the boiler will need to be switched on and

the %load that will need to be operated to maintain this temperature until the

heating up to delivery temperature will need to start.

• Gains by applying optimization are higher on long voyages (>30 days) while

minimal to nil at short voyages


Additional features and versions

Capability to model non-heated tanks and simulate the effect of

adjacent heated tanks

Capability to include non-oil cargoes (e.g. veg-oils and chemicals)

Capability to simulate temperature rise of chemicals carried in low

temperature and determine the need to apply cooling in transit

(e.g. propylene oxide cooling)

Capability to simulate vessels with steam deck heaters and deep

well pumps (e.g. FRAMO system)

Capability to simulate thermal oil systems

Thank you for your attention!

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