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DF-MFLWTI DiamondFace Mechanical Seal for Harsh Conditions in Refinery Pumps

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The TOTAL refinery at the Leuna chemicals site is one of the most state-of-the art facilities of its type in Europe. It processes around 33,000 tons of crude oil every day, most of which is pumped in from Russia.

Around three million tons of gasoline alone are produced in Leuna annually. This largely covers the demand from the German Federal States of Saxony-Anhalt, Saxony and Thuringia. Some 1,300 filling stations in the refinery’s catchment area are supplied from Leuna. The TOTAL refinery is also Germany’s largest manufacturer of methanol, which is an important base material for the chemical industry. Other products such as LPG, untreated gasoline and jet fuel, diesel, heating oil and bitumen complete the range.

Harsh Operating Conditions Lead to Seal Failures

A type SVCN7 pump from Ingersoll Dresser Pumps used as a stabilizer reboiler pump drives the bottom circuit of a stabilization column in which the lighter and more volatile components are separated from the reformate by distillation. The SVCN7 pumps the bottom product (stabilized reformate) to a furnace and then returns it to the bottom of the column. This mode of operation allows impurities such as pipe abrasion or catalyst residues to concentrate in the pumped column bottom, where they damage the mechanical seals. Solids in the medium and operation close to vapor pressure were the source of considerable problems for the competitor’s seal that was originally used.

Numerous failures and very short MTBF finally induced the operator to partner with EagleBurgmann to develop a permanent and reliable sealing solution. Just a few months later, EagleBurgmann was able to present an innovative solution that was validated in pilot operation and fulfilled the customer’s expectations.

DF–MFLWTI with Inserted Seal Face

EagleBurgmann’s design solution is based on the proven metal bellows design. As metal bellows do not need elastomer secondary seals, they are the perfect candidate for application at high temperatures. The MFLWTI is a double seal in tandem arrangement and is supplied ready for installation as a cartridge unit. It is supplied unpressurized to API Plan 21, Plan 52 and Plan 61. The key feature of the MFLWTI is the loosely inserted face of the seal on the product side, combined with the DiamondFace diamond coating of the contact surface. Even the choice of material for the seal face highlights its flexibility: the inserted ring offers more options in this regard than shrink-fit faces. It also impresses with its positive deformation behavior in operation and, as it is able to move, it will not tilt or cant.

The diamond coating makes the seal immune to dry running and solids in the medium. EagleBurgmann DiamondFace has already proven its worth in numerous applications in the oil and gas industry, refining and power station technology. With minimal friction, practically no wear and maximum chemical resistance, previously unachievable operating periods and MTBF or MTBR intervals are now possible, even under difficult conditions.

Successful Conversion, Increased Productivity

Since conversion to the newly-developed EagleBurgmann DF -MFLWTI metal bellows seal with DiamondFace coating in 2013, the pump and seal have been running at TOTAL Leuna continuously and without complaint with regular start / stop cycles caused by scheduled switchover to the parallel pump. Plant availability has been significantly increased as a result. Given this excellent experience, TOTAL Leuna has now decided to retrofit this sealing solution in the parallel pump as well.


Application Data

Medium: Hydrocarbons 

Pressure: p = 253.8 PSI (17.5 bar)

Temperature: t = 518 °F  (270 °C)

max. 572 °F (300 °C)

Rotational speed: n = 1,485 min-1

Materials: Q15Q15G/KHM6G1-Q12Q1K/KHM6G1

Seal supply system: API Plan 21, Plan 52, Plan 61
 

Groundbreaking Solution for the Future

This customer-specific sealing solution sets new standards in terms of product development. The design principle of a metal bellows seal with inserted seal face is currently under development to the series production stage in the new EagleBurgmann MFLWTI series.

In the future, there will be MFLWT(I) seals available with or without DiamondFace coating for use at temperatures up to approx. 752 °F (400 °C) and pressures up to 363 PSI (25 bar).

For more information on DiamondFace seals, contact us at info@us.eagleburgmann.com​

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