Fouling Mitigation

Heat Exchanger Fouling is a major problem for many processes, leading to reduced energy efficiency, restricted throughput and high maintenance costs.  Fouling is a complex phenomenon and the mechanisms involved are not completely understood.  Nevertheless, some of the parameters which aggravate fouling are well known and this knowledge can be applied to develop mitigation strategies.

Fouling characteristics are dictated largely by the properties of the thermal and hydrodynamic boundary layers. As a result, fouling mitigation strategies must take into account the conditions in this region. hiTRAN Wire Turbulators are a useful tool for controlling the conditions near the tube wall, especially in the laminar and transition flow regions

hiTRAN Thermal Systems have proven successful for direct fouling mitigation in the following scenarios:

• In services where low tubeside heat transfer coefficients yield high wall temperatures leading to increased chemical reaction fouling and coking. hiTRAN Wire Matrix Elements are used to reduce excessive wall temperatures in these tubeside controlled scenarios.
• In cooling duties where low tube wall temperatures lead to crystallisation fouling. hiTRAN elements can raise the wall temperature above critical levels, and have been especially successful in the winterisation of air-cooled heat exchangers handling hydrocarbon streams with high pour points.
• In exchangers operating at low flow velocities with increased risk of particulate and sedimentation fouling. In these cases the increased shear resulting from the application of hiTRAN Thermal Systems will assist solid particles to pass through the heat exhanger without deposition.

Click here to see what hiTRAN elements can do for fouling.

Vacuum residue/crude oil preheat exchanger with history of unplanned shutdiwns due to fouling. Replacement HeliTRAN Exchanger (hiTRAN/Helical baffle combination) with half previous area. 9 year operation with hiTRAN enhancement Re-tubed 2005 – hiTRAN System re-installed Fabrication: Mayr and Wilhelm Location: Erdol Raffinerie, Lingen, Germany. Courtesy: Deutsche BP AG

Heating cracked bottoms and coal tar mixture. Heating to 280degC. 28 years operation with negligible fouling. Previously plain tubes fouled to shut down every 2 to 3 months. Courtesy: Cabot Carbon