Intensification Insights from Chemical Looping Combustion Using Coal–Biomass Mixtures with Fe-Based Oxygen Carrier

Kevat, Mayur D.; Banerjee, Tamal

doi:10.3390/pr10071242

Cited by 1 publication

(1 citation statement)

References 36 publications

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“…In this study, authors demonstrate that this technology reduces carbon footprint compared with conventional hydrogen production technologies. Chemical Looping Combustion has previously been coupled with biomass pyrolysis for syngas or hydrogen production, but there are some disadvantages to direct biomass chemical looping pyrolysis, like looping material deactivation, a high solid recirculation rate, and the requirement for separation of looping materials and biomass ash [12][13][14]. For these reasons, CLC has been used to burn the volatile fractions [15] or the biochar fraction [16] in biomass pyrolysis for hydrogen or syngas production.…”

Section: Introductionmentioning

confidence: 99%

Life Cycle Assessment of Wheat Straw Pyrolysis with Volatile Fractions Chemical Looping Combustion

Mendiara,

Navajas,

Abad

et al. 2024

Sustainability

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Among the approaches to facilitating negative CO2 emissions is biochar production. Biochar is generated in the pyrolysis of certain biomasses. In the pyrolysis process, carbon in the biomass is turned into a solid, porous, carbon-rich, and stable material that can be captured from the soil after a period of from a few decades to several centuries. In addition to this long-term carbon sequestration role, biochar is also beneficial for soil performance as it helps to restore soil fertility and improves the retention and diffusion of water and nutrients. This work presents a Life Cycle Assessment of different pyrolysis approaches for biochar production. Biomass pyrolysis is performed in a fixed-bed reactor, which operates at a mild temperature (550 °C). Biochar is obtained as solid product of the pyrolysis, but there are also liquid (bio-oil) and gaseous products (syngas). The pyrolysis gas is partly used to fulfil the energy demand of the pyrolysis process, which is highly endothermic. In the conventional approach, CO2 is produced during the combustion of syngas and emitted to the atmosphere. Another approach to facilitate CO2 capture and thus obtain more negative CO2 emissions in the pyrolysis process is burning syngas and bio-oil in a Chemical Looping Combustion unit. Life Cycle Assessment was performed of these approaches toward biomass pyrolysis to evaluate their environmental impact. The Chemical Looping Combustion approach significantly reduced the values of 7 of the 16 environmental impact indicators studied, along with the Global Warming Potential among them, it slightly increased the value of one indicator related to the use of fossil resources, and it maintained the values of the remaining 8 indicators. Environmental impact reduction occurs due to the avoidance of CO2 and NOx emissions with Chemical Looping Combustion. The CO2 balances of the different pyrolysis approaches with Chemical Looping Combustion configurations were compared with a base case, which constituted the direct combustion of wheat straw to obtain thermal energy. Direct biomass combustion for the production of 17.1 MJ of thermal energy had CO2 positive emissions of 0.165 kg. If the gaseous fraction was burned by Chemical Looping Combustion, CO2 was captured and the emissions became increasingly negative, until a value of −3.30 kg/17.1 MJ was generated. If bio-oil was also burned by this technology, the negative trend of CO2 emissions continued, until they reached a value of −3.66 kg.

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