Shell Thermia Oil B
Paraffinic Mineral Oil For Closed Heat-Transfer Systems

Shell Thermia Oil B is a paraffinic mineral oil heat transfer fluid for indirec closed fluid heat transfer systems operating at bulk temperatures up to 320°C
provided that there is adequate pump circulation  to ensure that local film temperatures  on the heater surfaces do not exceed 340 °C 

Applications  
* Heat transfer fluid for indirect closed fluid heat transfer systems operating at bulk temperatures up to 320°C

Peformance Features
*Good low temperature properties 
Shell Thermia Oil B is fluid down to -18°C.Therefore no special precautions are necessary when closing down plant in cold
weather.Should the temperature fall below -18°C no expansion takes place.

*Low vapour pressure 
Below temperatures of 320°C, the vapour pressure of Thermia B is less than atmospheric pressure. High pressure
pipework and heat exchangers, used with vapour phase heat transfer fluids, are therefore unnecessary.

*Good heat transfer characteristics 
Shell Thermia Oil B has a relatively low viscosity with good temperature/viscosity characteristics which ensure high heat
transfer coefficients and consistent properties cover a wide temperature range.

Performance Benefits

*Low  cost 
*High thermal stability  
*Operating temperature range from -18°C to + 320°C.  
*Good oxidation stability  
*Low viscosity to promote high heat transfer coefficients
*Good viscosity/temperature characteristics  
*Low vapour pressure  
*Non-corrosive  
*Non-toxic  

Resistance to Cracking & Oxidation

Mineral oils are subject to two forms of degradation during use:
1. Cracking or the breaking down of hydrocarbon molecules by heat. Here a large molecule ruptures into smaller
molecules. Some appear as volatile gases,while others are unstable and polymerise into non-soluble deposits. The rate of
cracking is insignificant until temperatures of around 320 C are reached. Above this temperature the rate rises steeply.

2. Oxidation or the reaction of hydrocarbon oil with atmospheric oxygen. At room temperature this reaction occurs very
slowly, but it accelerates rapidly with increasing temperature. Oxidation produces acids in the oil and, at a later
stage, sludge. The viscosity of the oil generally increases.

Shell Thermia Oil B is based on carefully selected, highly refined, high viscosity index
paraffinic base oils. It has exceptionally good stability at bulk temperatures up to 320°C.The rates of cracking and oxidation are very low,giving maximum oil life.
This assumes an efficient fluid heater with good pump circulation so that film temperatures on the heater surfaces do not exceed 340°C.

Service Life
The life of Shell Thermia Oil B in any system depends on the design and usage of the system. If it is well designed and not subjected to abnormal workloads the life can be many
years. It is important to monitor oil condition regularly as rates of change in physical characteristics are more significant than actual values. A sample should be taken from any
newly-filled system about one week after start-up to establish a datum. Further samples should then be taken every 6 months and the results compared with the previous samples.
The properties which should be monitored are viscosity, acidity, flash points and insolubles content.