The term ‘oil flushing’ is used extensively in the process heating industry to refer to the cleaning of pipes and process equipment. Typical applications use immersion or circulation heaters that heat oil for circulating through the system to a desirable Reynolds number. Viscosity and temperature play critical roles in such conventional oil flushing. In many process applications, conventional oil flushing is not suitable to achieve the desired cleanliness.
Additional actions are needed to increase the cleanliness level. In addition, a lucrative benefit exists when oil flushing is done for a live system. The customer does not need to shut down the processing system. This saves valuable time and thus, money. All these techniques, however, use immersion or circulation oil heaters for heating the oil to the desired temperature.
Pulse-induced wave oil flushing
The oil used in the actual flushing is subjected to pulses that create sound waves. The oil becomes very turbulent because of sound waves. This turbulence helps to knock off the impurities on the interior of the pipes. The oil then flushes the impurities to the filter. The quality of cleaning is very high with this type of oil flushing.
Induced waves using PLC-controlled pulses
The method of inducing waves using PLC-controlled pulses is ideally applicable, where it is difficult to attain turbulent flow
The method of inducing waves using PLC-controlled pulses is ideally applicable, where it is difficult to attain turbulent flow (for example, coolers). The industry has found that these PLC-controlled waves from pulses are highly efficient at removing metal shavings from a net with fine mesh.
This oil flushing technique will also clean components that are difficult to reach. Both coolers and heat exchangers are target equipment for such PLC-controlled pulses with the end result of a high level of cleanliness.
Oil flushing for live systems
Live systems continue running when the cleaning is performed. This technique is highly technology-intensive. For example, this type of oil flushing is recommended for emergency shutdown systems or ESD, and hydraulic equipment on offshore oil and gas platforms. For the latter, production is ongoing, when oil flushing is carried out.
Monetarily, this is very attractive for businesses, as this type of oil flush reduces shutdowns, saving the cost of interrupted production. However, regular maintenance is kept intact. Note that, with pulse-induced wave oil technology, wells have considerably reduced closing time.
Oil flushing for umbilical and control lines
A completely different strategy is needed for oil flushing to clean the umbilical and control lines. These lines have a small diameter (about 4 mm) and are long enough to cover a long distance (as long as 3 km). An engineer’s acumen of the highest order is needed. The engineer must carefully select the oil (for example, a low viscosity).
Role of immersion and circular heaters
These heaters provide heated oil. Both immersion and circular heaters play a central role in all the above applications. During oil flushing, the engineer or technician must keep a close eye on the viscosity of the oil. Determining the correct viscosity is critical to performing oil flushing in the process industry.
For the process industry, both immersion heaters and circulation heaters are suitable for oil flushing. These heaters use a highly efficient heat transfer method where heat is applied to the oil. Both these types of heaters are equipped with devices and circuitry for temperature control.
