Application of 20% ammonia co-firing in a 1000 MW coal-fired power plant

To reduce CO 2 emissions from thermal power plants, increasing attention has been directed toward ammonia as an effective hydrogen energy carrier and as a fuel. A major technical challenge associated with ammonia combustion is the suppression of nitrogen oxides (NO x ) emissions formed from fuel-bound nitrogen. The authors have developed a 20% ammonia/coal co-firing (on an energy basis) combustion technology that achieves emission levels comparable to those of single coal combustion in burner combustion tests. To confirm applicability to an actual coal-fired power plant, an ammonia co-firing test was conducted at a 1000 MW commercial power plant under actual operating conditions. As a result, approximately 20% reduction in direct CO 2 emissions at the preheater inlet (per unit electricity generated), consistent with the carbon balance of the fuel mixture, was confirmed under actual 1000 MW commercial-scale operating conditions. NO x emissions were maintained at levels equal to or lower than those under single coal combustion, and no significant increase of unburnt carbon in ash was detected. Furthermore, plant operability under load-changing conditions was confirmed to be equivalent to that of conventional coal-fired operation. These results clearly indicated that ammonia co-firing can be applied to a 1000 MW-class opposed-firing boiler under uniform multi-burner co-firing conditions.