UNEP Project: “Reducing Mercury Emission from Coal Combustion in the Energy Sector” Process Optimization Guidance - POG Dr Lesley Sloss FRSC FIEnvSci Principal Environmental Consultant - IEA CCC Lead – UNEP Coal Partnership

Objective of the POG: A tool to help determine the most appropriate option to address mercury emission reduction needs. For whom? Individual coal-fired power plants and governments.

POG Document design  Contents: -Mercury Control Strategies - Energy Efficiency Improvement o Plant Modification o Coal Preparation - Maximization of Co-benefit Removal - Dedicated Mercury Removal - Multipollutant Control Technologies -Decision Tree -Post-control Issues -Profiles of Coal Use in the Four Countries -Examples of Costs Improving various areas of operation within an older boiler can reduce mercury emissions by up to about 7%. Many existing plants could be overhauled to improve both efficiency and output while reducing mercury emissions in an economic manner. Simple but complete guidance document Simple text summary boxes Interactive flow chart

The ultimate aim is to promote the use of the POG as a working tool to help reduce mercury emissions from existing plants. BUT Mercury behaviour in coal-fired plants is extremely complex

Mercury behaviour in coal combustion - the chemistry is complex Source: Niksa Associates

Mercury control decision tree The POG is designed to be a simple tool to allow plant operators to determine the most appropriate methods for mercury control

Decision tree - example The decision tree will direct the user to the most appropriate mercury control option, eg: -Can plant efficiency be improved? -Is coal switching, blending or cleaning an option? -Can the operation of existing pollution control systems be adjusted to enhance mercury capture – “co-benefit” effects?

In many cases, the simplest changes are the best Basic improvements in plant efficiency can reduce mercury emissions by up to around 7%, AND reduce running costs and emissions of other pollutants.

Coal treatment can improve mercury capture Chemical coal treatment can remove up to 70% mercury; Coal selection and blending can remove up to 80% mercury. However: the effectiveness of coal treatment is very coal specific and results can be poor in some cases

Importance of “Co-benefit” effects <90% mercury removal is possible in plants with existing sulphur and nitrogen oxide control systems; Existing control systems can be fine-tuned to enhance mercury capture; coal blending or the use of chemical additives can increase mercury capture.

Examples of control costs Approach Capital cost Operational costs Energy efficiency Coal-treatment Coal blending + + Coal additives + - Particulate control upgrade ++ - Co-benefit – sulphur + ++ Co-benefit – Nitrogen oxides +++ Activated carbon Costs are site specific - expert help is needed

Process of completing the POG Reviewed by international experts in 2009 Comments from Russia, China, and South Africa integrated A workshop will be held in India in 3rd quarter 2010 Finalized in 3rd quarter 2010 Final document will be posted on UNEP’s, IEA CCC’s and national websites

Any questions?