CO_2 Capture by Adsorption in Different Industrial Streams

摘要

Water vapor (varying in amount from 0 to 2%), carbon dioxide (around 260 ppmv) and some other minor gases present in the atmosphere absorb some of the solar thermal radiation keeping an energetic balance that allows Earth to be warmer than it should be (around -20C). These gases are known as greenhouse gases (GHG) because they act as a partial blanket for thermal radiation producing a natural greenhouse effect. A higher concentration of any GHG due to human activities (anthropogenic GHG), implies that the greenhouse effect will increase changing this energetic balance with still unknown consequences in global weather. As the country emissions of GHG are not uniform and as local economic factors have to be also taken into account, the commitments of the Kyoto protocol are not equal to all countries. In Portugal, according to the European burden sharing, emissions were allowed to increase up to 27% of the reference values in 1990: from 59.4 Tg/year to 75.4 Tg/year at the end of the first period of Kyoto. It was verified that the emissions of GHG in Portugal were 81.2 Tg/year (UNFCCC, 2005), which represents 36.7% higher than in 1990. For this reason, reductions in GHG emissions are necessary. In Portugal, it is possible to reduce GHG emissions in at least three different economic sectors: energy production, transport and waste. This work describes adsorption-based processes to capture CO_2 from different streams related to the energy industry: flue gas streams capture, landfill gas upgrade to fuel and hydrogen production.