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Processes in large-scale circulating fluidized bed combustors ('CFB COMBUSTORS')

Objective

Objectives and problems to be solved:
The purpose of this project is to assess the hitherto insufficiently known features of large scale circulating fluidised bed (CFB) combustors. The aim is to provide data for reliable operation and scale-up under the condition of high efficiency for electricity production and high reliability. The environmental consideration, low emissions of unburned matter, nitrogen and sulphur oxides, forms the background for the entire work. Another important reason for the investigation is that the CFB technique is new and almost no information is available on the detailed processes within a full scale CFB-furnace, except for data from laboratory and pilot scale plants: Thus, more data are needed. Description of work: The method of work is to explore the operational properties of a selected large scale (several hundred MW electric power) CFB and to extend measurements previously made in laboratory and pilot scale equipment (whose height is in the order of 10 m) to the scale of the large commercial boiler which has a height of the order of 40 m and a cross-section of a few hundred square meters. The quantities which are studied include: · hydrodynamic properties such as solids concentration, solids flux and boundary layers in the combustion chamber· characteristics of the combustion process; temperatures, gas concentrations and air-fuel mixing. · all boiler parameters under different steady state and dynamical conditions. To obtain these quantities field measurements on site in an existing power station are required. These measurements are carried out on a CFB boiler, which has recently been put into operation. The boiler is one of the largest in the world. In a preparatory phase holes are made in the boiler walls and measurement probes are manufactured, mostly based on previous experience, but adapted to the field conditions and the large size of the boiler. The measurements are carried out under steady state conditions as well as during load changes to study the dynamic behaviour of the boiler. Prediction and simulation methods are validated by means of the data obtained, to form a basis for design of new boilers and safe operation of existing ones. Expected Results and Exploitation Plans: In the main phase of the work measurements of vertical and horizontal profiles of solids density, temperature and gas concentrations are carried out. Also, data on the dynamic behaviour of the boiler are measured. These data are analysed and compared with existing data and compared with prediction methods. This should result in design methods for design of advanced boilers with a high efficiency and reliability and for safe operation of boilers. From a social point of view an improved efficiency and reliability of boilers will contribute a better environment, in line with the EU policy with respect to emissions.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CHALMERS UNIVERSITY OF TECHNOLOGY
Address

412 96 Göteborg
Sweden

Participants (6)

FOSTER WHEELER ENERGIA OY
Finland
Address
Sentnerinkuja, 2
00441 Helsinki
POWER PLANT 'TUROW' - BOGATYNIA
Poland
Address
Mlodych Energetykow 12
59 916 Bogatynia
TECHNICAL UNIVERSITY OF CZESTOCHOWA
Poland
Address
Dabrowskiego 69
42 200 Czestochowa
TECHNISCHE UNIVERSITAET HAMBURG-HARBURG
Germany
Address
Denickestrasse, 15
21071 Hamburg
VATTENFALL GENERATION SERVICES AB
Sweden
Address

162 87 Stockholm
VYSOKA SKOLA BANSKA - TECHNICAL UNIVERSITY OF OSTRAVA
Czechia
Address
Av. 17 Listopadu 15
708 33 Ostrava