Improving Reliability, Increasing Efficiency

1 Nov 2019  |
A leading refinery in the UK was having trouble with seal leakage from existing carbon box technology on their 150#, 600# steam turbines. Based on prior experience the refinery approached AESSEAL® for an alternative solution.

With no standard solution available, AESSEAL® initiated a development program in order to design a practical solution for the customer. The challenge for AESSEAL® was to:

  • Replace the existing carbon box seal
  • Utilise standard seal faces (ensuring modularity) with gas lift technology
  • Incorporate high temperature polymers
  • Utilise a graphite wedge shaft seal
  • Incorporate into a compact cartridge design that installs to the existing envelope and pcd
  • Cope with; high rotational speeds, as well as slow roll and wet steam

Working with the customer on the design and subsequent test program, AESSEAL® developed a solution for the application. After completion the customer witnessed in-house testing, the seal was installed to a known “Bad Actor”, on site for a 3 month trial. After 2 months successful operation the customer waved the rest of the trial and placed orders to install identical seals on two more steam turbines with a view to convert all the steam turbines on site.

Steam loss is a major problem on a Refinery as it incurs considerable costs. A significant benefit of the new seal is that it has eliminated steam leaks previously present; this represents a significant saving for the customer because:

  • The Refinery has approximately 150 Steam Turbines meaning the cost of steam has a major impact on the profitability of the business
  • There is a Health and Safety Issue as the steam produces a veil which affects vision causing a potential problem when working on or around the turbine
  • There is an environmental impact caused by the burning of extra fuels Steam leakage also contaminates the bearing’s lubrication causing them to fail prematurely.

Cost of steam loss from a Single Turbine:

Average steam loss rate from turbine: 200 lb/hr or 0.0907 T/hr
Turbine runs 24/7, 365 days a year: 8,760 hrs total
0.0907 x 8760 = 794.53 Tons of steam lost per year
Cost of steam @ £17.84 /T
794.53 x £17.84 = £14,174.45

Total Cost of lost steam / Steam Turbine/Year is approximately £15,000.00

Potential Saving to the Refinery with all the 150 Steam Turbines fitted with Steam Turbine Mechanical Seals is £15,000 x 150 = £2,250,000 per Year

Benefits of Steam Turbine Mechanical Seal Technology on this Refinery:

  • Increased turbine reliability
  • Reduced turbine maintenance costs
  • Reduced bearing contamination
  • Extends life as non-contacting technology
  • Elimination of Shaft Wear – generated by the Carbon seal
  • Greatly reduces steam loss and increasing efficiency

“These Steam Turbine seals are so good you should be looking at rolling them out to refineries worldwide”

Refinery Workshop Manager

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Welcome to AESSEAL® : A specialist in the design and manufacture of mechanical seals and support systems. Our Mechanical Seals are used in a wide range of pumps and rotating equipment worldwide to prevent liquids...

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