Fouling Factors

Fouling is a function of the system and the equipment used.  Parameters which influence the fouling rate in a system include: the type of fluid, the type of heat exchanger, the temperatures, the velocities and the materials of construction.  The actual fouling rate is different for each application. 

There are numerous resources for fouling factor values.  The best source is from existing operating facilities.  When production data is available, it can be used to calculate the actual fouling factors for the system.  Together with the maintenance and cleaning history, this provides the best resource for selecting the fouling factors for a particular application.

However, when production data is not available, one must rely on other sources.  Over the years, typical fouling factors have been compiled for various systems and fluids.  The tables below show some of these typical fouling factors:

Process Fluids

Fouling Resistance

 

(ft2-°F-hr/BTU)

Oils

         Fuel Oil #2

0.002

         Fuel Oil #6

0.005

         Transformer Oil

0.001

         Engine Lube Oil

0.001

  

Gases and Vapors

         Acid gas

0.002 - 0.003

         Ammonia vapor

0.001

         Chlorinated hydrocarbons vapors

0.001 - 0.0015

         Chlorine Vapor 

0.002

         CO2 vapor

0.001

         Compressed Air

0.001

         Hydrogen

0.0005

         Hydrogen (saturated with water)

0.002

         Light Hydrocarbon vapors (clean)

0.001

         Natural Gas

0.001 - 0.002

         Natural Gas Flue Gas

0.005

         Nitrogen

0.0005

         Polymerizable vapors (with inhibitor)

0.003 - 0.03

         Refrigerant Vapors (oil bearing)

0.002

         Solvent Vapor

0.001

         Stable Overhead Products

0.001

         Steam (non-oil bearing)

0.0005

         Steam (exhaust, oil bearing)

0.0015 - 0.002

  

Liquids

         Ammonia Liquid

0.001

         Ammonia Liquid (oil bearing)

0.003

         CO2 Liquid

0.001

         Chlorinated hydrocarbons liquid

0.001 - 0.002

         Chlorine Liquid

0.002

         DEG & TEG Solutions

0.002

         Ethylene Glycol Solutions

0.002

         Gasoline

0.002

         Heavy Fuel Oils

0.005 - 0.007

         Heavy Gas Oil

0.003 - 0.005

         Hydraulic Fluid

0.001

         Kerosene

0.002 - 0.003

         Light Gas Oil

0.002 - 0.003

         Light hydrocarbon liquid (clean)

0.001

         MEA & DEA Solutions

0.002

         Naphtha and Light Distillates

0.002 - 0.003

         Organic Heat Transfer Liquids

0.002

         Refrigerant Liquids

0.001

                                                       

Water

Fouling Resistance

Fouling Resistance

 

(ft2-°F-hr/BTU)

(ft2-°F-hr/BTU)

water temperature

 125°F or less

over 125°F

water velocity

3 ft/s or less

over 3 ft/s

3 ft/s or less

over 3 ft/s

     

Boiler Blowdown Water

0.002

0.002

0.002

0.002

Brackish Water

0.002

0.001

0.003

0.002

Condensate

0.0005

0.0005

0.0005

0.0005

Cooling Tower Water (treated)

0.001

0.001

0.002

0.002

Cooling Tower Water (untreated)

0.003

0.003

0.005

0.004

City or Well Water

0.001

0.001

0.002

0.002

River Water (minimum)

0.002

0.001

0.003

0.002

River Water (average)

0.003

0.002

0.004

0.003

River Water (muddy or silty)

0.003

0.002

0.004

0.003

Sea Water

0.0005

0.0005

0.001

0.001

Treated Boiler Feed Water

0.001

0.0005

0.001

0.001