These fluids are subjected to temperatures ranging from 300°F to 750°F depending on the need of the process industry. Over a period, however, the hot oils degrade.
Some of the contributors to degradation of the thermal fluid are…
- Exposure to oxygen (air)
- Low velocity of the fluid through the heating chamber and piping
- Improper heater selection
- Operating the system at temperatures above manufacturer’s recommended maximum temperature.
Pipe slag, mill scale, dirt, and dust accumulated in the system during installation or maintenance could be the pollutants.
Problems caused by contaminants
With the increase of contamination in the system, the fluid undergoes drastic property changes that affect the heat transfer capability of the overall system. Some of the issues could be…
- Wearing of rotating components (pump impellers, gears and shafts, mechanical seals, valve stems, etc.)
- Increased energy consumption
- Reduced capability of heaters and heat exchangers
- Increased viscosity of the oil
Different Industrial Filtration Methods
Traditional Filtration Method
Incorporate a strainer before the system pump. Strainers are signed to protect a piece of equipment such as a pump, valve, or flow meter.
They capture particles, preventing the particles from entering the pump and eventually the system.
A strainer must be cleaned regularly to prevent cavitations, which causes mechanical seal failure or magnetic de-coupling.
Full Flow Method
Another liquid filtration system is to install a filter in either a side stream or full flow
arrangement.
For both the types industrial filtration systems, the filter consists of a filter housing with a basket made of stainless steel, with perforations designed to trap fine particles.
In the case of side stream installation, the inlet of the filter is installed close to the discharge of the pump. The fluid is diverted through the filter, cleaned, and removed to the suction side of the same pump or a low-pressure return line.
The most efficient filtration is a forced flow and sidestream system arrangement that incorporates a pump and filter designed for high-temperature use.
This system has its filter pump to divert 5 to 10% of the process flow continuously through the filter as the heating system is operating. The entire fluid passes through the filter at least 15 to 20 times per day.
The inlet of the filter pump is plumbed into the discharge piping close to the process pump to take advantage of the turbulence in the tubing which keeps the solids in suspension.
The dirty fluid is forced through the filter, and the clean fluid is discharged into the same process line at a pressure higher than the system pressure or to the return pipeline downstream from the process pump.
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