Technical Discussion

• Viscosity Temperature
• Anup Sera
  Mott MacDonald Group
  GMT 12:04
  23rd Apr 2007

  Please advice on what fuel constants (Viscosity - Temperature relationship) to use for Marine Diesel Oil / Heavy Fuel Oils (around 1000 cSt @ 50 deg Cels)?
• Dr. Ram Vis
  Viswa Lab Corp.
  

  

  
  GMT 19:55
  23rd Apr 2007
  IP: x.x.203.241

  So far, the highest viscosity used in the ME is 700 cSt at 50 degC. Even for this fuel, you have to heat it to nearly 150 degC to achieve injection viscosity between 10 and 15 cSt. Engine makers do not reccomend heating oil beyond 150 degC. They also do not have facilites to heat both in the tanks and in the pipes to maintain the temperature upto the fuel injector.
  
  In my opinion 1000 cSt at 50 degC cannot be used in existing engines with existing equipment.
• Anup Sera
  Mott MacDonald Group
  GMT 04:17
  24th Apr 2007
  IP: x.x.2.27

  Dr. Vis,
  
  Thank you for the reply. My question was more on the following lines..the viscosity temperature relationship of hydrocarbons is approximated to the equation Ln(cSt) = A - B(deg K) by ASTM D 341. If I had two values of viscosities at two different temperatures I could fit those values in the above equation and found the fuel constants A and B and then interpolate to find the value of viscosity at a different temperature.
  
  Presently, I know the viscosity of a Heavy Fuel Oil which is 1000 cSt at 50 deg C. I wanted to know how to calculate the viscosity at a different temperature.
• Seymour Keith Forget
  Shell Marine Products Ltd
  GMT 15:27
  30th Apr 2007
  IP: x.x.0.6

  The utility BunkerCalc will carry out the calculations you require. The algorithm used is a more refined version of the one you quote.
  The default temp/visc constant is based on an average of real data from hundreds of measurement. This means the results you obtain will be approximate- though good enough for most practical purposes. The utility will allow you to create a tailored temp/visc constant if you have the MEASURED viscosity at two different temperatures, say 50C and 100C. This facility can be found under the "Calculate" menu item.
  
  BunkerCalc can be found at the following URL (copy and paste it in your browser).
  
  http://www.shell.com/home/Framework?siteId=marine-en&FC2=/marine-en/html/iwgen/leftnavs/zzz_lhn4_2_3.html&FC3=/marine-en/html/iwgen/products_and_services/marine_fuels/bunkercalc.html
• Anup Sera
  Mott MacDonald Group
  GMT 03:39
  1st May 2007
  IP: x.x.241.181

  Keith,
  
  Thank you for your help. I had used a similar application called Bunker Master from DNV Petroleum Services for the results. I assume, the default constants in the applications apply only for Bunker Fuels (Fuel Oils).
  
  Regards
  Anup
• Seymour Keith Forget
  Shell Marine Products Ltd
  GMT 13:28
  1st May 2007
  IP: x.x.0.6

  Anup.
  The default constants are applicable for Residual Fuels
• Anup Sera
  Mott MacDonald Group
  GMT 12:17
  2nd May 2007
  IP: x.x.241.180

  Thanks Keith
• Jon Watson
  Razaghi Meyer International
  GMT 11:35
  31st May 2007
  IP: x.x.13.36

  You may find the excel spreadsheet solution on the Razaghi Meyer Website useful.
  It is based on the ASTM D341 calculation, allows you to enter the viscosity of a fuel at two different temperatures and lets you also enter the density and the injection viscosity so you can determine the ignition index and injection temperature.
  Go here http://www.viscoanalyser.com/page8.html and download viscosity calculations. The density calculation spreadsheet allows you to determine the density at any temperature from the density at 15degC or the density at 15deg cf from the density at any other temperature.