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- Azzi, Elias Sebastian, et al.
(författare)
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Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden
- 2022
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Ingår i: Biochar. - : Springer Nature. - 2524-7972 .- 2524-7867. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Biochar is a material derived from biomass pyrolysis that is used in urban applications. The environmental impacts of new biochar products have however not been assessed. Here, the life cycle assessments of 5 biochar products (tree planting, green roofs, landscaping soil, charcrete, and biofilm carrier) were performed for 7 biochar supply-chains in 2 energy contexts. The biochar products were benchmarked against reference products and oxidative use of biochar for steel production. Biochar demand was then estimated, using dynamic material flow analysis, for a new city district in Uppsala, Sweden. In a decarbonised energy system and with high biochar stability, all biochar products showed better climate performance than the reference products, and most applications outperformed biomass use for decarbonising steel production. The climate benefits of using biochar ranged from - 1.4 to - 0.11 tonne CO2-eq tonne(-1) biochar in a decarbonised energy system. In other environmental impact categories, biochar products had either higher or lower impacts than the reference products, depending on biochar supply chain and material substituted, with trade-offs between sectors and impact categories. However, several use-phase effects of biochar were not included in the assessment due to knowledge limitations. In Uppsala's new district, estimated biochar demand was around 1700 m(3) year(-1) during the 25 years of construction. By 2100, 23% of this biochar accumulated in landfill, raising questions about end-of-life management of biochar-containing products. Overall, in a post-fossil economy, biochar can be a carbon dioxide removal technology with benefits, but biochar applications must be designed to maximise co-benefits.
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| 2. |
- Wen, Yuming, et al.
(författare)
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Pyrolysis of engineered beach-cast seaweed : Performances and life cycle assessment
- 2022
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 222
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Tidskriftsartikel (refereegranskat)abstract
- The blooming of beach-cast seaweed has caused environmental degradation in some coastal regions. Therefore, a proper treating and utilizing method of beach-cast seaweed is demanded. This study investigated the potential of producing power or biofuel from pyrolysis of beach-cast seaweed and the effect of the ash-washing process. First, the raw and washed beach-cast seaweeds (RS and WS) were prepared. Thereafter, thermogravimetric analysis (TG), bench-scale pyrolysis experiment, process simulation, and life cycle assessment (LCA) were conducted. The TG results showed that the activation energies of thermal decomposition of the main organic contents of RS and WS were 44.23 and 58.45 kJ/mol, respectively. Three peak temperatures of 400, 500, and 600 degrees C were used in the bench-scale pyrolysis experiments of WS. The 600 degrees C case yielded the most desirable gas and liquid products. The bench-scale pyrolysis experiment of RS was conducted at 600 degrees C as well. Also, an LCA was conducted based on the simulation result of 600 degrees C pyrolysis of WS. The further process simulation and LCA results show that compare to producing liquid biofuel and syngas, a process designed for electricity production is most favored. It was estimated that treating 1 ton of dry WS can result in a negative cumulative energy demand of -2.98 GJ and carbon emissions of -790.89 kg CO2 equivalence.
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