Vapor Flash

sSpirax Sarco FREME
(Flash Recovery Energy Management Equipment)

Leighton Hospital improved energy recovery and has reduced its carbon emissions by around 95 tonnes a year, cutting fuel bills by more than £10,000.

Intelligent engineering saves energy in a flash
Spirax Sarco FREME (Flash Recovery Energy Management Equipment) system is an innovative heat recovery system that enables steamsystem operators to achieve major energy cost savings by re-using all the heat from their condensate recovery systems. Returning condensate from the steam distribution system to the boiler house and using it to heat the boiler feedtank is an extremely effective energy saving measure. For every 6°C temperature boost in boiler feed water, 1% is knocked off a typical boiler energy bill. The costsavings in today’s climate of runaway energy prices will be substantial. Not all steam systems can recover the heat condensate, this is mainly because: 1. It would raise the feedtank temperature to above boiling point. In practice, the maximum boiler feedwater temperature is 85°C or 90°C – above this and damaging cavitation can be induced in boiler feed pumps. 2. Up to half of the recoverable energy inthe condensate can be lost as flash steam, which is generated as condensate leaves the pressurised steam system and returns to atmospheric pressure.

The high pressure solution
Spirax Sarco FREME overcomes this problem by feeding energy recovered from the condensate into the high pressure side of the feed pumps. The higher pressure means the boiler feedwater can be heated to over 100oCwithout boiling and causing pump cavitation. FREME works by passing condensate returning from the steam distribution system through a flash steam separation vessel. The separate flash steam and condensate streams each travel through a dedicated plate heat exchanger, where they heat the pressurised feed water before it enters the boiler. The two returning streams are then recombined and sent back to theboiler feed tank. At this point the combined stream is sub-cooled, so it is sufficiently warm to begin heating the cold feed but not hot enough to overheat the feed tank. Spirax Sarco can supply the whole installation as a pre-engineered, skid-mounted system. The responsibility and risk for ensuring that the system will operate as specified passes to us. This approach takes virtually all thestress out of designing, specifying, building and installing steam, hot water and other systems. Benefits of FREME • • • • • • • Recovers all energy from flash steam and condensate Removes unsightly plumes of flash steam Reduces steam raising costs and increases boiler efficiency Substantial savings on water, effluent and treatment chemical costs Prevents cavitation in the boiler feed pump Lowmaintenance Quick and easy to install

Don’t just take our word for it, here’s how FREME systems are currently saving steam operators thousands of pounds.

Award winning engineering
A FREME system from Spirax Sarco helped Abbey Corrugated become one of just 12 organisations across England and Scotland to be awarded the coveted “Carbon Trust Standard”. The installation of the Spirax Sarco system wasthe most valuable energy saving project undertaken by Abbey during its ongoing energy reduction campaign. Abbey produces 160 million square metres of corrugated board annually at its site in Blunham, Bedfordshire. It uses most of its plant steam to heat the plates and rollers in its three corrugators. The skid-mounted FREME system from Spirax Sarco recovers the energy in condensate and flash steamfrom around the plant and uses it to preheat the feed water to the boiler. Supplying hotter feed water reduces the amount of work the boiler needs to do to raise steam.

Before the project, water entered the boiler at around 68 or 70oC. It now arrives at between 138 and 142oC, according to Abbey Corrugated’s Facilities Manager, Paul Gale: "There was a lot of work going on at the time, but...