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The specific objectives of the project are:

• To demonstrate the performance of a full-scale burner capable of utilising difficult coals (i.e. low volatile content and/or high inert content) with regard to NOX emission, combustion efficiency, turndown without oil support, and flame stability.
• To obtain characterisation data for difficult coals, and to apply this data in improved combustion models.

In-furnace NO_x reduction technologies, and low NO_x burners in particular, are considered mature for application to a wide range of coals. However their performance deteriorates with the more difficult coals; i.e. low volatile coals (<10 daf) and those with high levels of moisture and/or high levels of inert materials. Such coals are being utilised increasingly in large export markets such as Eastern Europe, India, Asia and the United States.The problem with dif ficult coals is in achieving a stable performance with low emissions and efficient combustion. For example, the presence of high levels of moisture causes a delayed ignition resulting in the flame front not being stabilised within the burner throat as is normal with bituminous coals. Consequently, the burner is significantly less effective in controlling both NO_x emissions and combustion efficiency. The presence of high ash compounds this problem. Future trends show that the reduction of CO₂ emissions will become increasingly important. The widespread uptake of advanced supercritical technology will have a significant impact on this, there is typically 20 less CO₂ emitted from a modern supercritical boiler compared to sub-critical boiler technology. The application of advanced supercritical technology to a wide range of coals is greatly facilitated by the availability of suitable burners - the development of a burner type to fire a wide range of difficult coals will therefore allow the uptake of supercritical technology for these coals. In addition, it is recognised that more advanced burner technology will be required to complement future CO₂ capture options. For postcombustion capture (amine scrubbing), there is a need to keep excess air to a minimum as this reduces flue gas volumes and hence equipment and operating costs. For oxyfuel combustion, the design and performance of the burner will be critical both in maximisingt he combustion efficiency and in optimising flue gas recycle rates and hence the sizing of the gas handling components.

The proposed project aims to develop and demonstrate a new burner type capable of firing a range of difficult coals, at full-scale in a single burner test facility. The development phase will employ advanced modelling techniques for investigation of the effects of ignition, devolatilisation and burnout behaviour for difficult coals.This will be combined with detailed c oal characterisation data. Burner design and performance implications as a result of integrated CO₂ capture options will be considered.