Capturing carbon dioxide for a better environment
The 'Calcium cycle for efficient and low cost CO2 capture in fluidized bed systems' (C3-Capture) project worked to develop an advanced dry carbon dioxide (CO2) capture system applicable to both pulverised firing (PF) and circulating fluidised bed (CFB) boiler systems. The EU-funded project investigated two options for CO2 capture from boiler systems. The integrated atmospheric option for post-combustion capture from PF or CFB boilers was to be developed towards a pilot plant application. The second option aimed at an in situ capture system for pressurised fluidised bed combustion (PFBC) boilers. Project activities revealed that it is possible to establish a commercial system with both fluidised beds working under parameters close to standard fluidised circulating beds. It is also possible for most of the heat available in this capture system to be recovered using a new supercritical water-steam power cycle with very high efficiency. One of the system's main advantages is that the extra power generated significantly reduces the costs of CO2 capture. Related savings can thus cover the high investment cost required for system installation and operation. However, this calls for the guarantee of a minimum, predetermined number of operation hours. Further economical gain can be realised by selling the deactivated material purged from the system to cement industry companies. Experimental tests carried demonstrated the viability of the process for basic research size. To fully analyse the hydrodynamics of the process, however, a new experimental facility of a bigger scale needs to be built for large pilot testing. Such an approach will offer an intermediate validation step between the laboratory and demonstration, and allow for back-up plans to produce CO2 according to specification to be prepared.
