Energy and exergy analysis of chemical looping combustion technology and comparison with pre-combustion and oxy-fuel combustion technologies for CO2 capture

Abstract

A B S T R A C TCarbon dioxide (CO 2 ) emitted from conventional coal-based power plants is a growing concern for the environment. Chemical looping combustion (CLC), pre-combustion and oxy-fuel combustion are promising CO 2 capture technologies which allow clean electricity generation from coal in an integrated gasification combined cycle (IGCC) power plant. This work compares the characteristics of the above three capture technologies to those of a conventional IGCC plant without CO 2 capture. CLC technology is also investigated for two different process configurations-(i) an integrated gasification combined cycle coupled with chemical looping combustion (IGCC-CLC), and (ii) coal direct chemical looping combustion (CDCLC)-using exergy analysis to exploit the complete potential of CLC. Power output, net electrical efficiency and CO 2 capture efficiency are the key parameters investigated for the assessment. Flowsheet models of five different types of IGCC power plants, (four with and one without CO 2 capture), were developed in the Aspen plus simulation package. The results indicate that with respect to conventional IGCC power plant, IGCC-CLC exhibited an energy penalty of 4.5%, compared with 7.1% and 9.1% for precombustion and oxy-fuel combustion technologies, respectively. IGCC-CLC and oxy-fuel combustion technologies achieved an overall CO 2 capture rate of $100% whereas pre-combustion technology could capture $94.8%. Modification of IGCC-CLC into CDCLC tends to increase the net electrical efficiency by 4.7% while maintaining 100% CO 2 capture rate. A detailed exergy analysis performed on the two CLC process configurations (IGCC-CLC and CDCLC) and conventional IGCC process demonstrates that CLC technology can be thermodynamically as efficient as a conventional IGCC process.

Derivation of Kinetics and Design Parameters for a Carbonator Reactor in a Greenhouse Calcium Looping Process

“…The exergy of a stream is defined as the maximum amount of work obtainable when the stream is transferred from its initial state to a reference (or dead) state by processes in which the stream may interact only with the environment . The reference state considered herein for exergy calculations was 25 °C ( T 0 ) and 1 atm ( P 0 ; 1 atm=101325 Pa).…”

“…Thee xergy of as tream is defined as the maximum amount of work obtainable when the stream is transferred from its initials tate to ar eference (or dead) state by processes in which the stream may interact only with the environment. [24] Ther eference state considered herein for exergy calculations was 25 8C( T 0 )a nd 1atm (P 0 ;1atm = 101325 Pa). Thec alculation of exergy for as tream of matter can be divided into severalt erms,s uch as the potential (gh), kinetic (u 2 /2), and internal exergy.T he potential and kinetic exergy terms were neglected because the total plant height was negligible (potential exergy) and neither the incoming nor outgoing streams had considerable velocity (kinetic exergy).T he internal exergy of as tream can therefore be calculated as the sum of the physical( Ex ph )a nd chemical exergy [Ex ch ; Eq.…”

The Role of Synthetic Fuels for a Carbon Neutral Economy

“…Chemical looping combustion (CLC) concept offers not only a promising CO 2 capture route, but also further opportunities in efficient and clean electricity generation from coal, in integrated gas combined cycle (IGCC) power. Two process configurations, the integrated gasification combined cycle coupled with chemical looping combustion (IGCC-CLC) and the coal direct chemical looping combustion (CD-CLC), have been researched and identified as promising technologies for energy and capture efficiencies [42]. From the thermodynamic perspective CLC technology appears as a more favorable option for CO 2 capture than absorption based pre-combustion or oxi-fuel capture technologies.…”

“…From power plant experience, at 160 kJ/mol CO 2 for pre-or post-combustion capture, the ratio is 4:1. Whereas "chemical looping combustion" power plants deliver CO 2 with improved plant energy efficiency over direct pre-and post-combustion capture [40,42]. Capture from the atmosphere may eventually achieve better.…”

Investigations into the effects of volatile biomass tar on the performance of Fe-based CLC oxygen carrier materials

“…Chemical-looping combustion (CLC) is an indirect combustion process that utilises a regenerable solid oxygen sorbent (oxygen carrier (OC) material, OCM), typically a metal oxide, to transfer oxygen from the combustion air to the fuel such that direct contact between air and fuel is avoided [3][4][5][6]. CLC is a variant on an oxy-fuel carbon capture system that offers the potential for a much lower energy penalty as CO 2 separation is achieved intrinsically such that additional energy-intensive gas separation steps are avoided [7].…”