Authors*: Esa K. Vakkilainen1
Pekka Ahtila2

ABSTRACT
Recovery boiler mass and energy balances are needed for the
performance testing of recovery boilers, mill energy wide control
systems, and in calculating the air emission data. Typically, recovery
boiler balances are mainly based on 1996 TAPPI publication
“Performance Test Procedure: Sodium Base Recovery Units”, the
use of which is problematic in Europe because of its view that the
losses from the recovery of process chemicals are counted when
determining the recovery boiler steam generation efficiency. A low
efficiency leads to taxation and legislative problems in some European
countries. There is a newly accepted European standard for steam
generator acceptance tests: EN 12952-15:2003 “Water-tube boilers
and auxiliary installations - Part 15: Acceptance tests”. This paper
examines how the standard could be applied to recovery boilers to
find out the net efficiency which is shown to be approximately the
same as for other biomass boilers, not 10% lower. A new and more
accurate method to calculate losses from convection and conduction
is discussed. In addition, a suggestion on how to handle borate
autocausticization in the recovery boiler furnace is made.

*Authors’ references:
1. Lappeenranta University of Technology, P.O. Box. 20, FI-53581 Lappeenranta, Finland
2. Aalto University, P.O. Box 4100, FIN-02015, Espoo, Finland
E-mails: esa.vakkilainen@lut.fi , pekka.ahtila@aalto.fi
Corresponding author: Esa K. Vakkilainen - E-mail: esa.vakkilainen@lut.fi

O PAPEL vol. 72, num. 12, pp. 58 - 65 DEC 2011