32 research outputs found

    Simultaneous production of biochar and thermal energy using palm oil residual biomass as feedstock in an auto-thermal prototype reactor

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    In developing countries, the technology used for biomass carbonization requires major retrofits for an efficient conversion of the residual biomass produced in the palm oil mills into biochar. This study analyzes a prototype of a small and modular auger reactor (P-SMART) that uses untreated kernel shells as feedstock to produce biochar and thermal energy. The P-SMART does not require inert gases during operation, neither diesel nor natural gas for the initial heating process. This study shows that the carbonization process can be driven by the energy generated during pyrolysis gas combustion (auto-thermal conditions) from a biomass load capacity of 30 kg/h. During the auto-thermal operation, the thermal energy generated by pyrolysis gas combustion is higher than that required by the carbonization process. The carbon monoxide concentration in the flue gas during the auto-thermal operation was 197 mg/Nm3 which is lower than the European eco-design requirement of 500 mg/Nm3 (both measured at 11% vol. O2, dry gas). The biochars produced during auto-thermal operation have a macro-porous structure with a pore radius that ranges from 0.42 to 12.48 μm. The carbon content and the molar H/Corg and O/Corg ratio of the analyzed biochars are in accordance with the European guidelines for the sustainable production of biochar of less than 0.7 and 0.4 respectively. Moreover, relevant soil nutrients were observed in the KS ash, namely: silica (30 wt%), potassium (8.2 wt%) and phosphorous (3 wt%).publishe

    Potential for Farmers’ Cooperatives to Convert Coffee Husks into Biochar and Promote the Bioeconomy in the North Ecuadorian Amazon

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    Improving the livelihoods of communities living in fragile ecosystems, such as tropical forests, is among the main strategies to promote their conservation and preserve wildlife. In the Ecuadorian Amazon, farmers’ cooperatives are recognized as an important mechanism to improve the socioeconomic conditions of local communities. This study analyzes the integration of pyrolysis processes to convert agricultural waste into biochar as a way to implement the bioeconomy in these organizations. We found that post-harvesting processes in the studied farmers’ cooperatives are similar, and coffee husks are a potential feedstock to produce biochar. Although the environmental policies in Ecuador consider the valorization of agricultural waste, we did not find any specific standard to regulate the operation of pyrolysis facilities. Nonetheless, conversion of agricultural waste into biochar can contribute to (i) replacement of subsidized fossil fuels used in drying processes, (ii) prevention of environmental pollution caused by accumulation of waste, (iii) emergence of new income sources linked with the provision of carbon sequestration services, and (iv) the long-term maintenance of soil fertility. Currently, demonstration projects are needed to stimulate collaboration among farmers’ cooperatives, academia, the government, international cooperation agencies, and existing forest conservation initiatives.Fundação para a Ciência e a TecnologiaBundesministerium für Bildung und ForschungPeer Reviewe

    Conversion of quinoa and lupin agro-residues into biochar in the Andes: An experimental study in a pilot-scale auger-type reactor

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    In the last decades, the cultivation of quinoa and lupin became an important source of income for Andean farmers due to the demand for high nutrient-density foods from the Global North. The increase in the cultivation intensity caused by this exogenous demand led to the overexploitation of local ecosystems and a decrease in soil fertility. As an alternative to recover and improve soil quality, this work uses a pilot-scale auger pyrolysis reactor, implemented in the Andes, to assess the conversion of the agro residues generated in the post-harvesting processes of quinoa and lupin into biochar for soil amendment. Following the European Biochar Certificate guidelines, the pyrolyzed quinoa stems can be classified as biochar while the pyrolyzed quinoa husks can be classified as pyrogenic carbonaceous material. Both can be used for soil amendment considering their molar ratios (H/Corg, O/Corg) and carbon content. It was not possible to carbonize lupin stems and seedcases. Despite the altitude (2,632 m.a.s.l), the CO concentration during the carbonization of quinoa stems and husks were 1,024.4 and 559 mg/Nm3, this last, near the European eco-design standard of 500 mg/Nm3. A subsequent SWOT analysis showed the need to explore low-cost and low-complexity pyrolysis reactors that allow the decentralized conversion of agro residues at the farm-scale. The development of local standards to regulate the production and use of biochar is also essential to grant the safety of the processes, the quality of the products, and mobilize funds that allow implementation at relevant scales

    Palm oil kernel shell as solid fuel for the commercial and industrial sector in Ecuador: tax incentive impact and performance of a prototype burner

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    The Ecuadorian industrial and commercial sectors are in general supported in the use of diesel for energy purposes. An alternative to replace diesel could be the use of palm oil residual biomass as solid fuel. It is estimated that 57.7% of the capital costs required to implement a biomass boiler that use untreated palm oil kernel shell (KS) as fuel in replacement of a diesel boiler would be covered by in force tax incentives. Nonetheless, untaxed and subsidized diesel utilization coupled to the important capital and operating costs associated to the biomass boiler results in relatively high payback periods, within the range of 6 to 7.9 years. Analyzing a base case, it is observed that replacement of diesel by KS results in a reduction of 8 times the fuel costs. Implementation of pre-treatment processes (e.g. pelletizing) could increase the KS price, affecting the potential to lower the costs of thermal energy production. Accordingly, utilization of raw KS for thermal energy production was demonstrated using a horizontal burner prototype. The experimental analysis of the KS combustion process shows that combustion efficiency (99.8%) is as high as that observed in other type of biomass burners. During the steady state operation periods, CO concentration in the flue gases (260.1 mg/Nm3) was below the limit established by the European standards for solid fuel boilers (500 mg/Nm3). Ash sintering was observed in the grate during the combustion experiments. The ash discharge process induced periodic fluctuations in the combustion chamber temperature profile as well as fluctuations in the flue gas composition. Despite these localized and periodic temperature and gas composition fluctuations, in the whole, and considering longer periods of operation, the combustion system was under steady state conditions and showed to be suitable for energetic valorization of untreated KS.publishe

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    Sex differences in oncogenic mutational processes

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    Sex differences have been observed in multiple facets of cancer epidemiology, treatment and biology, and in most cancers outside the sex organs. Efforts to link these clinical differences to specific molecular features have focused on somatic mutations within the coding regions of the genome. Here we report a pan-cancer analysis of sex differences in whole genomes of 1983 tumours of 28 subtypes as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We both confirm the results of exome studies, and also uncover previously undescribed sex differences. These include sex-biases in coding and non-coding cancer drivers, mutation prevalence and strikingly, in mutational signatures related to underlying mutational processes. These results underline the pervasiveness of molecular sex differences and strengthen the call for increased consideration of sex in molecular cancer research.Sex differences have been observed in multiple facets of cancer epidemiology, treatment and biology, and in most cancers outside the sex organs. Efforts to link these clinical differences to specific molecular features have focused on somatic mutations within the coding regions of the genome. Here we report a pan-cancer analysis of sex differences in whole genomes of 1983 tumours of 28 subtypes as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We both confirm the results of exome studies, and also uncover previously undescribed sex differences. These include sex-biases in coding and non-coding cancer drivers, mutation prevalence and strikingly, in mutational signatures related to underlying mutational processes. These results underline the pervasiveness of molecular sex differences and strengthen the call for increased consideration of sex in molecular cancer research.Peer reviewe

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts.The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that -80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAFPeer reviewe
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