The first sliding pressure steam accumulator was patented by McMahon in 1873. Steam accumulators were reinvented 100 years later in the Scandinavian pulp & paper industry. “Steam Age” application is still valid in the modern industry; boilers holdup volumes are getting smaller, oil price keeps rising, biomass boilers have longer response and emission reduction are a topic. The 3rd Generation steam accumulator was introduced in 1996 in Kirkniemi, Finland.
The 3rd Generation steam accumulator design features are:
- H-type steam rake and vertical mixing pipes (turn-down ratio 30:1, good steam distribution and smooth operation)
- Internal ”dry pan” demister (high volumetric efficiency and dry steam)
- Stress calculation with fatigue analysis required (modern design codes, extended NDT, mean pressure difference and number of cycles per lifetime)
- Optimized wall thickness and material strength (thermal sleeve, loose supports, welding details, PWHT and boiler water quality)
- Advanced controls (”active” or ”passive” accumulator, one display screen, fully automated description, single master pressure transmitter, smart level control)