ASTM D341 how it works

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Online Viscosity Systems
Multi-curve Referral
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Temperature Vs. Kinematic Viscosity ASTM D341
log.log (v 0.7) A-BlogT v kinematic
viscosity cst T temperature deg Kelvin
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using ASTM D341 log.log (v 0.7) A-BlogT

• two process variables
• kinematic viscosity (cst)
• temperature (OK)
• two constants A B
• therefore with two sets of calibration data....
  AB can be found

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Calculations

• log.log (v 0.7) A-BlogT........(i)
• let v 128.58cst at 40 OC
• log.log (129.28) A-Blog(313).............(ii)
• let v 15.00 cst at 100 OC
• log.log (15.70) A-Blog(373)...............(iii)
  
• (ii) - (iii) and solve for B B3.24
• substitute B in (ii) and solve for A
• log.log (15.70) A-3.24log(373).............(iv)
  

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calculating base viscosity

• now substitute A and B in (i)
• log.log (v 0.7) 8.41-3.24logT........(v)
• and now
• enter the temperature of interest in T, e.g. 50
  OC, the base temperature
• find v
• log.log (v 0.7) 8.41-3.24log(323)
• v 80.0cst at 50 OC

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System Benefits

• optimum viscosity performance real time process
  measurement
• continuous on-line process measurement
• closed loop control against base viscosity
• all service items within the clients normal
  maintenance apability

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the multi-curve method

• for products where quality changes dramatically
• for multiple products
• combines ASTM equation with ratio technique
• for bunker monitoring and blending control

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Heavy Fuel Oils
Calibration Curves
Product Curve
Viscosity
Temperature
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determining base viscosity
Logarithmic scale
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A simple Installation
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