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Slagging and fouling prediction by dynamic boiler modelling (slagmod)

Objective

In order to promote a wide spread utilisation of decentralised biomass combustion operational problems like slagging, fouling and corrosion have to be solved or reduced. Based on existing and measured steam data, an on-line dynamic model of the A thermodynamic model to monitor the heat transfer of a biomass fired fluidised boiler has been developed and successfully applied. The modular structure of the model makes it a tool for detecting and analysing local slagging and fouling deposits. The model could also be used as a "soft sensor" to analyse the varying fuel quality. If obtained in parallel, fuel and ash measurements can therefore be correlated to the simulation and give an insight in the deposit mechanism. During the project the necessary sub-models and gross plant models have been developed: - Dynamic boiler model (Fortran based) for the Uppsala boiler (USTUTT) - Dynamic boiler model (ACM) for the Nyköping and the Uppsala boiler (TUD) - Steady state boiler model (Fortran based) for the monitoring of Uppsala and Nyköping (IST) - NTUA sub models (radiation model, conduction model, deposit properties model and heat transfer model) Results: During the winter 2000/2001 an extensive measurement campaign at two Swedish power plants was carried out to provide the necessary input data for the offline development and validation of the models. During this campaign the combustion temperature in the plants was measured continuously by acoustic pyrometry.

Furthermore fuel and ash samples were taken and analysed in the IVD fuel laboratory as an additional input for the heat exchanger model (NTUA). During summer 2001 a first set-up of a new designed slagging probe was used in a test facility to receive additional information about the deposit. This was done in co-operation of TUD and USTUTT at the IVD. The available data from the winter measurement campaign have been used in the offline models for further tests. During winter 2001/2002 the steady state model of TUD was successfully tested online at the Uppsala and the Nyköping plant as well as the dynamic model for Nyköping. Included to another measurement campaign AAU provided impactor measurements and fuel / ashes analyses. Essentials of a user interface have been set-up by IST. During summer 2002 the slag characterisation at the USTUTT test facility was continued with an improved probe in co-operation with NTUA and TUD. The integration of the WADA model to the monitoring model of IST was not ready at the end of the project term due to delayed testing of the WADA model at the power plants in Sweden. Both programmes have been tested separately and successfully during the project term to fulfil the objectives of the project. They are working on a stand alone basis at the moment.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITAET STUTTGART
Address
Pfaffenwaldring 23
70569 Stuttgart
Germany

Participants (5)

AABO AKADEMI UNIVERSITY
Finland
Address
14-18B,lemminkäinengatan 14-18 B
20500 Turku / Abo
DELFT UNIVERSITY OF TECHNOLOGY
Netherlands
Address
Mekelweg 2
2629 CD Delft
INSTITUTO SUPERIOR TECNICO
Portugal
Address
Avenida Rovisco Pais
1096 Lisboa
NATIONAL TECHNICAL UNIVERSITY OF ATHENS
Greece
Address
Heroon Polytechniou St. 9
10682 Athens
VATTENFALL AB
Sweden
Address
Laemtlandsgatan 99
162 87 Stockholm