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
Without Steam Turbine Seal 
With Steam Turbine Seal
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
