Executive Summary : | Chemical looping combustion (CLC) is a two steps process with inherent carbon dioxide separation. In CLC combustion of gaseous fuel takes place without direct contact between oxidizer and that makes it different from conventional combustion. In addition to indirect combustion of fuel, the technique provides a way to separate carbon dioxide without the need of chemical separation technique as required for post-combustion carbon capture and storage (CCS) methods. It is considered to be a cleaner way to proceed for combustion of fuel for power generation and other large scale applications. This technique is energy intensive and requires replacement of conventional combustion chamber with CLC chamber. With these modifications CLC can be incorporated in conventional thermal power systems for improved performance and cleaner production.
CLC is carried out in two steps and it consists of two interconnected fluidized bed reactor called fuel reactor and air reactor. In first step the fossil or gaseous fuel is oxidized in fuel reactor by reacting with lattice oxygen of metal oxides termed as oxygen carrier (OCs). The oxidation of gaseous fuel produces carbon dioxide and water and reduced metal oxide. The second step is carried out in air reactor where reduced metal oxide gets re-oxidized by reacting with air . The product of the cycle emits negligible amount of pollutant gases and produces unreacted nitrogen and oxygen from oxidizer, so it can be directly releases to the atmosphere. The combined amount of heat liberated during this two process cycle is equivalent to the heat generated in conventional combustion process.
However durability of CLC process largely depend upon properties of oxygen carrier like mechanical strength, resistance to agglomeration , reactivity with the hydrocarbon fossil fuels, and oxygen carrying capacity [1-2]. Conventional oxygen carriers have its own limitations whereas its nanoparticle counterpart could play an important role to enhance the acceptability and performance of modern CLC system. The detailed thermo-mechanical characterization and effect of nano sized oxygen carrier is priori unknown and it is expected to help significantly reduce harmful emissions along with improved thermal performance.
To standardized procedure for preparation of solid state nano-particle oxygen carrier in combustion
Comprehensive material characterization of nano sized oxygen carrier with respect to size and composition
Experimental investigation on effect of variation in size and composition on redox reaction between nano-particle oxygen carrier and gaseous fossil fuel in chemical looping combustion
Development of model for chemical looping combustion process with nano-particle oxygen carrier
Comparison of experimental and computational results
Comparison of energy and exergy destruction efficiency between conventional combustion chamber and CLC combustion chamber |