Experimental demonstration of pressurized chemical looping combustion in an internally circulating reactor for power production with integrated CO2 capture

Mogahid Osman,Abdelghafour Zaabout,Schalk Cloete,Shahriar Amini

doi:10.1016/j.cej.2020.125974

Mogahid Osman, Abdelghafour Zaabout + Show 2 more

Open Access

https://doi.org/10.1016/j.cej.2020.125974

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Abstract

This study presents an experimental demonstration of pressurized chemical looping combustion (CLC) in an internally circulating reactor (ICR). The ICR concept is a novel alternative to the conventional interconnected fluidized bed CLC configuration as it eliminates all cyclones, loop seals and solids transport lines, and it can be pressurized in a single pressure shell. Stable operation with high fuel conversion was established for about 40 h of operation at pressures up to 6 bar, achieving reasonable CO2 purity and capture efficiency (up to 97%). The solids circulation rate was found to increase with increasing the operating pressure at a constant fluidization velocity with no effect on CO2 capture and purity. The experimental campaign also examined the effects of solids inventory and fluidization velocities in the air and fuel reactors. The CO2 purity and capture efficiency were most sensitive to the solids inventory, whereas the solids circulation rate was most sensitive to the air reactor fluidization velocity and the solids inventory. A correlation for solids circulation rate was derived from the collected experimental data, thus providing a robust tool for designing an ICR system for pressurized operation. This correlation can assist in further scale-up and demonstration of the ICR concept in commercial scale.

Highlights

Carbon capture and storage (CCS) has a great potential of reducing CO2 emissions from the utilization of fossil fuels, which would play a significant role in fulfilling the ambitions of the Paris agreement to limit future temperature rise below 2 °C [1]
This study presents an experimental demonstration of pressurized chemical looping combustion (CLC) in an internally circulating reactor (ICR)
The CLC system carried out in two steps, in the fuel reactor the fuel interacts with an oxygen carrier to fully oxidize to CO2 and H2O, the reduced metal oxide is re-oxidized in a flow of air in the air reactor, ready to start a new cycle and producing heat for power production [2,3,4]

Summary

Introduction

Carbon capture and storage (CCS) has a great potential of reducing CO2 emissions from the utilization of fossil fuels, which would play a significant role in fulfilling the ambitions of the Paris agreement to limit future temperature rise below 2 °C [1]. Chemical looping combustion (CLC) is a promising technology for power production based on fossil fuels combustion with integrated CO2 capture and with a reduced energy penalty. If the CLC system is pressurized, the hot depleted air from the air reactor can be used for efficient power generation in a downstream combined cycle. Pressurized chemical looping combustion (PCLC) has the potential for maximizing the power plant efficiency by using a combined cycle instead of the steam cycle used with atmospheric pressure boilers. High pressure combustion increases the condensate temperature, the condensate in the fuel reactor outlet stream can Nomenclature

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