NO x Reduction Technology in PF Boilers

Technical, environmental and economic assessments were performed, using the ECLIPSE process simulator, for a supercritical coal fired PF power station to investigate the impact of NO x reduction technologies. The study was modelled upon the Amer 9 Power Station at Geertruidenberg, The Netherlands, and both combustion and post‐combustion NO x reduction technologies were evaluated. SCR gave the largest reduction in NO x emissions to below 50mg/Nm 3 , but at an electricity cost of 2.44p/kWh, compared with 2.23p/kWh for the reference case and 2.26p/kWh for coal‐over‐coal reburning. The latter produced a 50% reduction in NO x emissions to below 200mg/Nm 3 . Use of a microniser, to reduce coal particle size, in coal‐over‐coal reburning is not justified, unless its absence produces excessive unburnt carbon losses or requires a reburn coal 50% more expensive than the main coal. With natural gas‐over‐coal reburning, an unrealisable natural gas price of £0.98/GJ is required to make it competitive with coal‐over‐coal reburning and natural gas prices between £1.76/GJ and £1.93/GJ are required for it to compete with SCR.