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Working within the petroleum and petrochemical industries comes with a particular array of manufacturing challenges. First, you’re dealing with an environment prone to dust, excessive heat and stringent energy regulations. These industries must guarantee plant operation to avoid costly shutdowns. It’s also imperative to minimize costs in order to remain competitive in a field that’s ALWAYS competitive.

In many cases, complications start within the components and systems put in place around the plant. Whether it’s a faulty gearbox, lubrication issue or environmental impact due to hazardous operating conditions, this equipment must remain efficient and reliable in order to maintain ideal operating conditions.

Magnetic couplings utilize permanent magnets to transfer torque. They can provide significant advantages particularly in areas where customers seem to need to replace components and systems at an alarmingly high rate or regularly shutdown production lines for maintenance and reliability issues. In this blog, we’ll consider the advantages of both fixed gap magnetic couplings as well as variable gap magnetic couplings in the petroleum and petrochemical industries.

Fixed gap magnetic couplings

There are many advantages to utilizing fixed gap magnetic couplings compared to standard dry flexible metal shim pack couplings or lubricated gear-type couplings.

• These magnetic couplings do not fatigue like flexible metal couplings such as shim pack type so they cannot fail due to misalignment stresses. Additionally, they cannot fail due to lack of maintenance.
• 
Magnetic couplings cannot overstress the shafts and cause shaft fatigue failures. Also dampen torsional pulsations.
• No precision alignment of driver to driven with laser is required.
• 
Able to transmit power up to 1,200 hp for latest air-cooled models without 
requiring external cooling devices.
• 
Major reduction in bearing housing vibration levels of both driver and driven components compared to 
standard couplings, vibration readings ranging from a 25 – 70 percent reduction have been observed.
• Eliminates sudden high torque start-up shock to pump mechanical seals due to induction motors starts that can produce 2x rated torque. This allows a smooth startup of pumps without torsional shock thus extending M-Seal life.
• 
While there is a slight loss of energy due to slip which occurs in some magnetic couplings (about 1% average to max 2% in some applications), this can be changed to positive energy gain by varying the coupling gap to reduce driven machine output thus saving driver energy.
• Another advantage is that standard couplings can transmit vibration from misalignment, thus causing energy loss through coupling flexure and high bearing load friction, while magnetic couplings transmit zero misalignment. This advantage reduces energy loss.
• 
No lubrication is required. Zero maintenance is required.
• No parts are subject to fatigue under normal installation.

Variable Gap Magnetic Couplings

Magnetic variable speed couplings are a special type including an automatic speed control actuator. The simplistic Adjustable Speed Drive (ASD) design is ideally suited to pump, fan and blower applications, providing the energy savings of speed control without the problems often associated with Variable Frequency Drives (VFDs). In these installations, system complexity and issues caused by vibration and misalignment are reduced.

The advantages of MagnaDrive Variable Speed Control include:

• Eliminates inefficient discharge control valves, dampers and expensive VFDs
• Up to a 66 percent yearly energy savings with lowest total cost of ownership
• Accepts greater misalignment
• Eliminates vibration transfer between motor and load
• Increases seal and bearing life
• Eliminates external shock loading to driven machine

Next week, we’ll look at a specific oil & gas application example from Saudi Aramco, a leading integrated energy and chemicals enterprise in Saudi Arabia.