Material solutions for USC plants with CCS
Carbon capture and storage (CCS) has become an important strategic element for meeting the European Commission’s CO2 reduction targets. However, CCS has a big impact on a power plant’s performance, with an expected efficiency loss of approximately 7% - 15%. To overcome this drawback, a plant’s efficiency or the level of biomass co-firing needs to increase. Unfortunately, the potential benefits of those two approaches may be limited. Live steam temperatures well in excess of 700°C are necessary to compensate for efficiency losses from CCS and to achieve a net efficiency of 45%; however, the quality of the coatings and materials currently available will not allow for such high temperatures.
The NextGenPower project, aims to demonstrate the potential of new alloys and coatings for boilers, turbines, and interconnecting pipe work. A uniquely integrated project, the NextGenPower concept is based on innovative pilots that support the EU’s goal of increasing the efficiency of existing and future pulverized coal power plants. Higher plant efficiency is needed, because the EU hopes to capture and store enough CO2 to realize a 20% reduction in emissions by 2020. Progress towards higher efficiency can be achieved by
> Adopting USC steam conditions in new power plants (well in excess of 700°C).
> Combining CCS with higher percentages of biomass co-firing (>20% in energy terms)
The overall project objective is to develop and demonstrate the potential of coatings and materials suitable for use in USC conditions (for new coal-fired power plants where biomass is co-fired). Coatings for existing power plants, where biomass is co-fired, are also being piloted. The following scientific and technological objectives for this project include
> To demonstrate the use of Ni-alloys for pulverized coal-fired boilers, which exhibit acceptable levels of creep and fatigue when exposed to high temperatures
> To demonstrate the use of cost-effective fireside coatings, which are compatible with available, affordable tube alloys, for coal-fired boilers capable of withstanding the corrosive conditions envisaged with USC conditions and the environment created by biomass co-firing under various parameters
> To demonstrate the use of cost-effective steam-side coatings/protective layers that can extend the life of boiler tubes and interconnecting pipe work, and to facilitate the use of cheaper alternative materials without compromising component life or reliability
> To demonstrate the use of Ni-alloys for interconnecting pipe work between boilers and steam turbines, which are capable of withstanding the high temperatures envisaged with USC conditions, and to explore alternative design options that would allow the use of cheaper and more readily available materials than Ni-alloys.
> To demonstrate the ability to cast, forge, and weld Ni-alloys for critical steam turbine components
> DNV KEMA, the Netherlands
> About 12 partners from 7 countries are involved
> EU Seventh Framework Program
> Duration: May 2010 – April 2014