In situ carbon dioxide capture and fixation from a hot flue gas

Abstract

The emission of CO2 globally from coal fired power plants is reportedly high, in the order of billion tons of CO2 per year. The amount would be much higher if the other types of fossil fuels used to generate electricity are accounted for. The present treatment or capture of this gas using conventional methods may require that the gas be injected underground for permanent storage. This solution depends on complicated machinery and suitable underground reservoirs but it poses the risk of accidental release of the gas due to seepage or negligence. A preferred method that is proposed in this presentation is by capturing and mineralizing carbon dioxide in situ. The method includes pressure swing adsorption in which highly temperature durable adsorbent is used. Annexed to the pressure swing system is a fixation unit that runs continuously and simultaneously to convert the captured CO2 into soda ash. The process requires only CO2. The other chemicals namely, sodium chloride and ammonia, can be regenerated and recycled. The process achieves almost a complete loop, making it highly sustainable.