Projects

Projects: Projects for Investigator

It is generally accepted that improvements in coal particle size distribution are beneficial to carbon burnout, and considerable emphasis is placed on the optimisation and maintenance of coal pulverising equipment at utility power plant. The modelling of carbon burnout has been the subject of a number of recent and ongoing projects, some of which have received the financial support of the DTI, and significant technical advances have been made. However, there is an absence of available plantdata to demonstrate the effect of coal particle size distribution on carbon in ash, which would allow the validation of this aspect of CFD and engineering models of burnout. This project seeks to address the shortfall.

The overall aim of the project is to establish good quality plant data to demonstrate the effect of changing coal fineness in a controlled way. Specific objectives are:

• to obtain full scale plant data on the impact of coal particle size on carbon in dust and NO_x formation
• to obtain data on the impact of coal particle size and coal quality on carbon in dust and NO_x formation by means of combustion trials on a 1 MWth single burner combustion test facility
• to provide coal and flyash samples for detailed laboratory testing and analysis, to establish whether there are differences in the nature of the flyashes arising as a result of the extent of grinding
• to analyse the data arising with the engineeringmodel being developed under the auspices of the Improvement in Combustion Efficiency in Utility Boilers DTI Project No. 139 and thereby to validate its ability to predict the effects of coal size distribution
• to undertake CFD modelling of the plant tests to establish the validity of this modelling approach (building upon the work undertaken previously in the earlier DTI sponsored project)

The main activity will be full-scale plant testing, where the coal particle size distribution will be adjusted by changes to the pulverising equipment classifiers. The plant testing will be supported by laboratory scale studies of the coals fired and flyashes arising, along with mathematical modelling utilising the results of these studies.

Combustion tests will also be undertaken with a range of PF fineness levels on a single burner 1 MWth combustion test facility. This will provide data on the influence of coal particle size with perfect fuel and air distribution.

As far as is practicable the coal quality for the test facility and plant trials will be the same.