Design and Operation of a 1 MWth Pilot Plant for Fluidized Bed Based CO2 Capture Processes

One of the main causes of climate change is anthropogenic CO2 which is emitted from usage the use of fossil fuel for energy production. No large reduction of emissions through reducing energy consumption or by replacing fossil fuels with alternative energy resources can be achieved in the near future. CO2 capture and sequestration (CCS) technologies are a strong alternative method of achieving carbon reductions from fossil-fired power plants and other industrial sources.

Several processes have been investigated for CO2 capture, e.g. MEA scrubbing, oxyfuel combustion and IGCC. All these processes have the disadvantage of enormous efficiency losses of about 10 to 14 %, which raises questions about the economy and suitability of these processes. This thesis focuses on two alternative CO2 capture methods, which promise lower efficiency losses and costs than those seen in the processes mentioned above; however, they comparatively stand in the early stages of development.

One of these processes is the carbonate looping process, which captures CO2 by means of lime. It is a retrofit option for conventional fossil-fired power plants. The CO2-containing flue gas of a power plant reacts with CaO to form CaCO3 in what is known as a carbonator. This exothermic reaction takes place under temperatures of approximately 650 °C. To use the sorbent economically, a regeneration process takes place in what is called a calciner at 900 °C. This step is the endothermic part of the loop; therefore, it needs heat input to control the reactor temperature.