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LLTE – Low Low Temperature Economizers

A sustainable world requires us to maximize efficiency and to avid waste of valuable streams like heat and water. Nooter/Eriksen is working on both with the patent pending application of the Low Low Temperature Economizer (LLTE).


Located downstream the conventional heat exchange bundles, the LLTE is an economizer coil assembled with thermoplastic material tubes in order to safely operate under dew point in full condensation, due to excellent resistance both to acid water and sulfuric acid corrosion.

This represents an unique industrial solution to manage the severe corrosion caused to steel materials when operating under exhaust gas condensation point.

In this way, either in existing plants or in newly designed plants, the LLTE designed by Nooter/Eriksen allows recovery of additional heat from the exhaust gas before being discharged in the stack. This improves the overall CCPP efficiency by increasing the steam production, or by providing heating to other process fluids in the plant, or generating district heating application. Moreover the LLTE permits recovery of valuable water otherwise dumped in the atmosphere as exhaust gas humidifies.

The LLTE represents a very flexible solution in terms of performance and geometry selection. It can easily be adapted to operating or newly designed boilers. It can be handled and installed, and does not require major changes to the boiler structure, and simply improves the performance at base & partial loads.

The LLTE has been designed under patented Nooter/Eriksen solution NOOT F675US, that gives Nooter/Eriksen the exclusive right to supply it in CCPPs.
Nooter/Eriksen received the first order from ENI for a retrofit to one of the Ferrera Erbognone HRSG delivered by NE in 2002. This will be the first worldwide application of this kind in a combined cycle.

Due to quick return of investment time, the LLTE is a simple and attractive solution for our customers.

Low Low Temperature Economizer (LLTE)