CO2 emissions and their accumulation in the atmosphere are causing global warming, and the subsequent rise in the average temperature of the Earth’s atmosphere and oceans.
According to the recent Special Report on Global Warming of 1.5ºC of the Intergovernmental Panel on Climate Change, created by the World Meteorological Organization and the United Nations Environment Programme, the capture and storage of carbon dioxide continues to be a key tool in decarbonizing industrial sectors that are difficult to electrify (such as the cement and steel industries) and in achieving negative emissions in certain processes powered by renewable biomass.
The process of CO2 capture requires it to be separated from other gases emitted in industrial processes for its subsequent storage in the subsurface in depleted oil or gas fields under supercritical conditions. A small part of the captured CO2 flow could also be used to power new manufacturing processes for products that contain carbon, thereby avoiding the extraction of combustible fossil fuels for that purpose.
One family of highly promising CO2 capture processes is based on the reversible carbonation-calcination reaction of CaO/CaCO3, in which calcium oxide (CaO) is used to capture CO2 in the form of calcium carbonate (CaCO3) in order to release it later through the calcination of this CaCO3 under conditions with high concentrations of CO2 (burning a combustible substance with pure CO2 or providing heat to the calciner indirectly).
The application of these very high-temperature reversible reactions for the development of energy-efficient processes is relatively recent. The Spanish National Research Council has been one of the global pioneers in this field, both in the Institute for Carbon-based Science and Technology and in the Institute for Carbon Chemistry.
Many years of research have borne fruit in the form of patents, scientific work and the La Pereda pilot plant.
After several years of basic research, in 2002 the Council applied for a patent (ES2192994A1) on the use of heat generated in a combustion chamber during the endothermic reaction of a calciner to recycle sorbent, using metal walls that separate the combustion chamber from the calciner or through an inert solid moving between the two chambers.
The Council has been the source of half a dozen active patents that have been extended internationally and have advanced new processes or improved existing ones.
Its researchers have published many of the most cited scientific works in this field, including the world’s first results from a continuous 30 kW pilot plant. This led to the establishment of the AIE LA PEREDA economic interest group between the Council and ENDESA and HUNOSA, two Spanish companies in the energy sector, for the development and implementation of these technologies at a 1.7 MWt plant tin La Pereda (Asturias, Spain/attached photo).
The North American company Foster Wheeler later acquired a percentage of the exploitation rights to these technologies, acting as a technologist in the AIE LA PEREDA project.
The La Pereda pilot plant is the world’s biggest and most active in the field of carbonation-calcination, having had active contracts from 2009 to 2019 and accumulating more than 4,000 hours of testing.
A variant of the process for biomass (ES2339733A1, owned by the company Naturgy), that makes it possible to generate electricity with negative emissions, was developed in parallel in a 400 kWt pilot plant at the thermal power plant in La Robla (León, Spain).
In recent years, there has been less interest in carbon capture and storage technologies in the electricity generation sector throughout Europe, despite the great success and market penetration of renewable electricity. However, carbon capture and storage technologies continue to be a priority in Europe in industrial sectors that are difficult to electrify, such as the cement industry (where the Council is conducting research under the Cleanker project) and the steel industry, where the Council will expand its patented technology (PCT/ES2010/070585) in an ArcelorMittal plant to Technology Readiness Level 7, as part of the European C4U project.
The Spanish National Research Council (Consejo Superior de Investigaciones Científicas) is a state agency for scientific research and the technological development of Spain. Its aim is to encourage, coordinate, develop and disseminate multidisciplinary scientific and technological research in order to contribute to the advancement of knowledge and to economic, social and cultural development.
The Council, by means of its 120 centers throughout Spain, carries out research in all scientific and technological fields. The Council is the number one patent applicant in Spain, applies for more European patents and international patents (applications under the Patent Cooperation Treaty) than any other body in Spain, and has the third highest number of European patents of all European public bodies.
In the last five years, the Council has licensed 437 technologies for market exploitation, of which 216 have been protected by patents.