Hunosa (Spain)

Postcombustion CO2 capture by calcium looping using circulating fluidized bed technology, CFB-CaL, is evolving to tackle industrial sectors that are difficult to decarbonize. In addition to the known advantages of CFB-CaL (i.e., retrofittability and competitive energy efficiencies and cost), the fuel flexibility by using renewable biomass in the oxy-fired CFB calciner and the possibility to reach extremely high CO2 capture efficiencies in the carbonator are demonstrated in this paper. Results from the latest experimental campaigns in the TRL7 CFB-CaL pilot of the La Pereda are reported, treating over 2000 N m3/h of flue gases in the carbonator with a firing capacity of biomass pellets up to 2 MWth in the oxy-fired calciner. A new strategy to reach high CO2 capture efficiencies (above 99% in some cases) in the carbonator has been tested. This involves decoupling the carbonator in two temperature zones by cooling the solids-lean top region to below 550 °C and ensuring that a sufficient flow of active CaO reaches such a region.

Resumen: La explotacion de hidrocarburos no convencionales, entre ellos el del metano contenido en las capas de carbón (cbm: Coal Bed Methane), ha experimentado un gran auge en los últimos anos. La Cuenca Carbonífera Central Asturiana (ccca) ofrece un gran potencial para desarrollar proyectos de este tipo, como lo atestiguan las investigaciones y valoraciones llevadas a cabo en esta zona desde los años 90 del siglo xx. Hunosa, la empresa minera estatal que opera actualmente en la ccca, ha realizado una serie de investigaciones en los últimos años encaminadas al estudio de las posibilidades de desarrollar proyectos vinculados al aprovechamiento de metano del carbón, ya sea vam, amm, cmm o cbm. Los resultados obtenidos muestran que el cbm es el tipo de proyecto más adecuado actualmente para desarrollar en la ccca.Palabras clave: carbón, cbm, Cuenca Carbonífera Central Asturiana, hunosa, metano.Abstract: The exploitation of unconventional hydrocarbon deposits has increased in recent years. Methane from coal seams represents one of these gas resources. The Central Asturian Coalfield (cac) has a high potential to develop these types of projects, as many studies and research carried out since the 90’s (20th century) confirm. Hunosa, the stated-owned coal-mining company that currently operates in this area, has performed research for the last years focused on assessing the feasibility of developing projects related to methane exploitation: vam, amm, cmm and cbm. These studies have concluded that cbm projects would be the most adequate technique to be implemented in cac.Keywords: coal, cbm, Central Asturian Coalfield, hunosa, methane.

Coal mine discharges in several European countries were investigated as part of the European Commission’s MANAGER project. The emphasis of the project was identification of priority pollutants and potential remedial approaches. The main identified priority pollutants were sulphate (all countries) and iron (all countries except Greece). High concentrations of chloride (particularly in Germany and Poland) were associated with discharge of saline mine waters linked to the presence of fossil sea water; these mine waters also had high boron concentrations, in contrast to chloride-rich waters in UK that are linked to recent sea water inflow. Concentrations of trace metals vary among countries, but radium is an important contaminant in barium-rich waters with low sulphate concentrations, essentially in Poland. Concentrations of trace metals and metalloids were generally low because of their relative scarcity in coal strata and adsorption onto ferric oxides and hydroxides, but they still often exceeded the environmental quality thresholds.