Marie Anheden

Oxyfuel combustion for coal-fired power generation with CO2 capture—Opportunities and challenges

Publisher Summary This chapter illustrates that the increased carbon dioxide level in the atmosphere is the dominating contributor to increased global warming. Carbon dioxide is emitted to the atmosphere through combustion of fossil fuels in power plants, automotive engines, for industrial use and for heating purposes. The world is currently depending on the use of fossil fuels for its energy supply, and will continue to be so for a long time yet to come, due to the abundant sources of in particular bituminous coal and lignite. Small-scale renewable electricity production is available on the market today, but the cost of avoiding CO2 emissions through renewable is at present very high. It discusses oxyfuel recycle combustion is a highly interesting option for lignite-based power generation with CO2 capture, due to the possibility to use advanced steam technology, reduce the boiler size and cost and to design a zero-emission power plant. This technology, also poses engineering challenges in the areas of combustion and heat transfer, boiler design, boiler materials, energy-efficient oxygen production, and flue gas processing. The overall challenge is to design a robust plant that has a sufficiently low total cost of electricity so that it is interesting to build, but it must also have a sufficiently low variable cost of electricity so that it will be put in operation as a base load plant once it is built.

CO2 quality requirement for a system with CO2 capture, transport and storage

Publisher Summary This chapter discusses the CO2 purity/specification for a CO2 capture transport and storage system. A list of potential impurities in the captured CO2 stream is provided for considerations to bring forward a practical CO2 specification that could be used as a guideline for CO2 capture, transport, and storage, and is also acceptable for environmental regulations. The aim of CO2 capture is to reduce the emissions of CO2 and other pollutants from fossil fuel fired power plants. To achieve this aim, the capture process should provide a concentrated CO2 stream for further transport and storage. The quality of the captured CO2 stream technically depends on the fuel used, approaches used for the combustion and the capture process. The CO2 quality requirements are defined by the limitations set by CO2 transport, storage, safety and environmental regulations, and the cost. There are generally no strong technical barriers to provide high purity of CO2 from the flue gas of fossil fuel fired power plants; however, high purity requirements are likely to induce additional costs and energy requirements resulting in a loss of power plant efficiency. Excessively strict requirements on CO2 quality should be avoided to reduce costs associated with CO2 capture.

Techno-economic assessment of catalytic gasification of biomass powders for methanol production

This study evaluated the techno-economic performance and potential benefits of methanol production through catalytic gasification of forest residues and lignin. The results showed that while catalytic gasification enables increased cold gas efficiencies and methanol yields compared to non-catalytic gasification, the additional pre-treatment energy and loss of electricity production result in small or no system efficiency improvements. The resulting required methanol selling prices (90-130€/MWh) are comparable with production costs for other biofuels. It is concluded that catalytic gasification of forest residues can be an attractive option as it provides operational advantages at production costs comparable to non-catalytic gasification. The addition of lignin would require lignin costs below 25€/MWh to be economically beneficial.