Pipe Degradations in Oil Refineries Requiring Oil Flushing

Pipes are used heavily in the oil refinery industry to transport chemicals both in liquid and in gaseous form. Pipes also carry water and steam at different temperatures for different operational requirements in crude oil refining. Pipes suffer from degradation over time for various reasons such as when transporting corrosive and combustible liquids and gases. Any pipe degradation is highly detrimental to the oil refinery industry, compromising safety as well as leading to shutdown and production loss. Pipe degradation refers to blockage, leaks, or deposit formation.

WATTCO develops and manufactures a variety of professional-grade immersion heaters and circulation oil heaters for the oil refinery industry (See Figure 1.) These heaters are an integral component of oil flushing equipment used to clean pipes, transportation lines, and lubing hoses.

Using WATTCO electric heaters, hot oils are circulated throughout the piping network to remove contaminants or deposits/scales. If there is any risk of fire for using oils, hot water glycol or steam is used for cleaning. Flushing ensures that piping network equipments operate in smooth and efficient manner; production is maintained and failure is prevented.
 

 
VISCOSITY
Viscosity plays an important role in oil flushing. The equipment operator must use correct viscosity for oil flushing of pipes. For example, low viscosity is chosen so oil can flow well inside the piping network or viscosity value is high enough (chosen) to carry the contaminants to the filter. Both immersion and circulation heaters are able to heat the oil to a temperature between 50 and 60 degrees Celsius consistently. This temperature that is suitable for flow turbulence (Reynolds number: 3000) without causing any oxidation.

Selection of heaters for oil flushing
 
Immersion heaters such as flanged and screw plug heaters are suitable for oil flushing in the oil refining industry. Oil is heated very efficiently as heat is directly applied to the oil. Sophisticated oil flushing equipment uses immersion heaters for cleaning pipes.
 
Temperature control is extremely important in oil flushing. Immersion heaters have a Type E2 terminal box that includes high quality electrical wiring that adheres to National Electrical Code. The electrical wiring (of the terminal box) increases safety in case of fire or explosion for high temperature application in an oil refinery. Another safety feature is the automatic switching off of the electrical circuit when high limit has been exceeded.
 
Circulation heaters are suitable for oil flushing as they are used to pre-heat heavy oils (with high viscosity) for smooth pumping. Circulation heaters are also used to keep a consistent temperature for light and medium-weight oils, along with its smooth flow characteristics. The heater is insulated so no heat can escape.
 
The construction of the industrial heater and its components (for example, sheath material) are important for oil flushing.  The process engineer must choose a sheath material based on the: 1) viscosity 2) specific density 3) corrosive properties of the heated medium and 4) the corrosion resistive properties.
 
Selection of the proper heater also depends on heat or Watt requirements, flange sizes, number of elements, kilowatt ratings and terminal enclosures.
 
The technician must take sufficient precautions when there is any danger of fire or explosion – this is particularly applicable for oil refinery industry. WATTCO provides specific terminal enclosures for use in adverse situations, for example, in explosion-prone environment of an oil refinery.