Magnetic Coupling Solutions at Saudi Aramco (Advantages of Magnetic Couplings in Oil & Gas Applications II)
In the previous blog, we examined the advantages of both fixed gap magnetic couplings as well as variable gap magnetic couplings in the petroleum and petrochemical industries. Today, we’ll put what we’ve learned to the test by looking in-depth at a pump system application.
Abdulrahman Alkhowaiter is a machinery consultant at Saudi Aramco, a leading integrated energy and chemicals enterprise in Saudi Arabia. For several key applications, the company has replaced conventional couplings with their magnetic counterparts.
The reason? They require less maintenance than conventional couplings, they are suited for pump applications, and they offer a reduction in mechanical seal failures—to name a few.
In 2010, a small change from a standard coupling to a magnetic coupling in a dissolved gas floatation bubble maker pump (DGF) provided several key manufacturing benefits.
First, let’s provide a little background on the application itself. A DGF is an oil/water separation technique where solids, oils, and other contaminants are lifted to the surface of the liquid and removed. This is an effective and flexible solution to treating produced waters.
These pumps—currently in use at the company’s Safaniya Onshore Utility Plant G-26—were originally driven by 60 hp motors at 1,800 rpm, and coupled to gearboxes to transform the speed up to the required 3,200 rpm for the application.
This configuration, however, was experiencing high vibration and noise which prevented the DGF system from working properly. Manufacturing challenges included misalignment of the system as well as overheating inside the gearbox.
This resulted in lube oil coolers that required 5-7 fan blowers each with 3 hp. Alternatively, water-oil heat exchangers were proposed, which required replacing the heat exchangers with a circulation water system.
A solution utilizing magnetic coupling technology was proposed. The motors were replaced with 60 hp versions that run at 3,600 rpm—close to the required 3,200 rpm, but not quite. By installing MagnaDrive magnetic couplings, they were able to reduce the speed to the required 3,200 rpm.
The installation of the MagnaDrive couplings solved several problems at once. By matching the rotational speed with the system design requirements, the use of a complicated gearbox was now unnecessary. This not only saved on valuable floor space, but also eliminated the need for a lubrication system. Moreover, thanks to the magnetic coupling technology, vibration transfer between shafts was eliminated and vibration levels reduced.
In general, Alkhowaiter said magnetic couplings provide many technical advantages over conventional dry couplings. For example, they meet Saudi Aramco standards that require a non-lubricated coupling. They also eliminate the need for coupling precision alignment during maintenance beyond a basic hand check by the machinist. They are well suited to pump applications since speeds are almost always within the 3,600 rpm range. Additionally, the pumps benefit from a reduction in mechanical seal failures.
To date, there have been ten magnetic coupling installations at Saudi Aramco. The company plans to continue utilizing the technology in future applications. Since the first
magnetic coupling was patented in 1999, there have been more than 15,000 MagnaDrive & Fluxdrive Magnetic Couplings and Adjustable Speed Drives (ASDs) installed globally.
These installations can be found in pumps, fans, blowers, centrifuges, and bulk handling equipment in order to achieve higher reliability, greater energy savings and reduced vibration. The industries served include oil and gas processing, water and wastewater treatment, pulp and paper manufacturing, power generation, cement, mining, chemical/food processing, irrigation, maritime, HVAC systems, and more.
Next week, we’ll take a closer look at magnetic coupling technology utilized in pumps with hydrocarbon flammable liquids from Saudi Aramco.