Environmental impacts of a chemical looping combustion power plant

Rebecca J Thorne,Evert A Bouman,Kyrre Sundseth,Asuncion Aranda,Tomasz Czakiert,Jozef M Pacyna,Elisabeth G Pacyna,Mariusz Krauz,Agnieszka Celińska

doi:10.1016/j.ijggc.2019.04.011

Abstract

Chemical Looping Combustion (CLC) is a promising CO2 capture option since it inherently separates CO2 from other flue components, theoretically with low energy penalty. Here, a Life Cycle Assessment model was developed of a theoretical hybrid CLC (HCLC) power plant facility utilising experimental data for CuO based oxygen carrier (OC) production and oxygen capacity. Power plant models with and without post-combustion CO2 capture, recognised as the most mature capture technology, acted as environmental performance targets. Results show that when OC is produced at lab-scale without optimisation, almost all (>99.9%) lifecycle impacts per kWh electricity from an HCLC plant derive from the specific OC material used, giving a total of ˜700 kg CO2eq/kWh. This is related to high electrical input required for OC processing, as well as high OC losses during production and from plant waste. Only when processing parameters are optimised and OC recycling from plant waste is implemented - reducing fresh OC needs – is the environmental impact lower than the conventional technologies studied (e.g. 0.2 kg CO2 eq/kWh vs. ˜0.3-1 kg CO2 eq/kWh, respectively). Further research should thus focus on identifying OCs that do not require energy intensive processing and can endure repeated cycles, allowing for recycling.

Highlights

As part of a European transition to a greener society, increasingly stringent emission targets are being set
It is not realistic to compare a theoretical hybrid CLC (HCLC) plant based on lab-scale experimental data, without any assumed improvement associated with the upscaling to an industrial process
The magnitude of improvements that would be expected to occur when scaling up oxygen carrier (OC) production from lab to industrial (t) scale are unknown, optimisation of certain equipment and methodologies would certainly result in a large degree of process and equipment optimisation, as well as recovery and reuse of waste

Summary

Introduction

As part of a European transition to a greener society, increasingly stringent emission targets are being set This includes the EU 2020 climate and energy package, specifying a 20% reduction of greenhouse gas (GHG) emissions by 2020 with respect to the 1990 baseline (EC, 2018a) and the 2030 climate and energy framework extending the reduction to at least 40% by 2030 (EC, 2018b). A subset of fluidised bed combustion, Circulating Fluidised Bed (CFB) is a combustion technology utilising relatively low temperatures that results in low NOx emissions (IEA CCC, 2013). Despite these improvements, the only way to significantly lower CO2 emissions and meet GHG reduction targets whilst still utilising coal resources is by implementing carbon capture and storage (CCS)

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