No description available.

No description available.

Biochar is increasingly gaining momentum in the context of climate change mitigation and its production in Sweden could potentially become a large-scale system. Carbon stability in biochar is a crucial factor to assess its the carbon sequestration potential. Currently specific methodologies to assess biochar carbon site-specific stability are missing. This work aims at filling in part this knowledge gap assessing stability for Sweden specific soil conditions. Moreover, this work aims at assessing biomass feedstock availability for biochar production from a system perspective and aims at estimating biochar production and carbon dioxide removal potentials in Sweden. Preliminary carbon stability specific thresholds are provided for soils at 10°C temperature and, thus, representative for Sweden conditions. Carbon dioxide removal functions are obtained for different feedstock categories (woody, herbaceous, biosolids and animal waste) dependent on pyrolysis conditions (Highest Treatment Temperature), and conditions for maximum carbon removal are assessed. The need for future analysis in order to validate the presented results is highlighted. Future work should focus on collecting new experimental results of biochar mineralisation based on the requirements presented in this work. An opportunity mapping for biochar production system is provided, focusing on some aspects of the interaction of the former with existing systems (agricultural, energy production and waste management). From the results of the opportunity mapping, an inventory of the available feedstock for biochar production is presented including woody residues, sewage sludge, manure, garden waste and straw. From the available feedstocks, biochar production and carbon dioxide removal potentials are estimated to range respectively between 0.9 and 1.7 million tbiochar/year and between 2 and 4.2 million tons CO2 sequestered per year (in a 100 years perspective). In terms of carbon dioxide removal potential, biochar production can significantly contribute to the goals set by Sweden in terms of climate change mitigation and emission offsetting for 2030 and 2045, potentially covering all the measures needed from carbon sinks from forest and land. It was found that the most significant contribution derives from the availability of woody residues in Sweden, whose analysis should be prioritised for future assessment of feasibility of biochar large scale production.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第24712号 / エネ博第455号 / 新制||エネ||85(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻 / (主査)教授 河本 晴雄, 教授 亀田 貴之, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

Yes / Studies estimate that Africa's urban population is expected to triple over 40 years, from 395 million in 2010 to 1.339 billion in 2050. Challenges associated with increasing urbanisation and the rise of large cities in the African sub-region represent critical challenges to the environment and the rich ecosystem. The growing population, particularly in most cities in Africa, has resulted in increasing demand for non-degradable consumable waste products, changes in lifestyle and consumption patterns, and rising demand for transportation and associated solid waste disposal problems, especially tyre waste. However, few studies have examined circular economy practices such as tyre pyrolysis to attenuate Africa's ever-increasing waste disposal challenges. Moreover, most of these studies failed to account for specific risk-based decision-making attributes in an integrated way, such as technology readiness, risk identification, carbon footprint analysis, supply chain and procurement factors, and financial risk quantification. As a result, to the best of our knowledge and understanding, research-based tyre recycling feasibility practices are limited and scattered. We contribute to the literature by providing systematic literature on tyre pyrolysis in Africa from 2008-2022 inclusive, covering 16 African countries. To address tyre waste in Africa, this chapter provides a 10-point strategy on how pyrolysis can be integrated into production plants and associated businesses to minimise tyre waste in Africa. / The full-text of this article will be released for public view at the end of the publisher embargo on 29 July 2025.

In order to better understand the changes occurring in the internal environment of the pyrolysis process a method of monitoring the internal environment in real time is the key objective of this study. To accomplish this objective four tasks were laid out in order to develop an effective way of monitoring the changes in gases present as pyrolysis is occurring as well as in material activation processing. For all processing the self-activation process was used which combines pyrolysis and thermal activation into a single step process. In the first task 10 hard wood species were activated and the resulting properties were compared to see the impact of wood species on the resulting carbon structures. In order to understand the impact of gas concentration on the resulting carbons the second task developed a gas sensor array which effectiveness was corroborated using GC-MS and then comparisons of the changes in the resulting were made. For the third task the gas sensor array was used to analyze the production of CO2 gas and a triple Gaussian model was developed to model the changes in gas production throughout processing. H2 gas production was modeled in the fourth task using the same Gaussian model as the third, where the results of both gas productions were compared showing the impact of processing parameters on gas production. With these four tasks completed we can see how our processing effects wood species similarly but at different rates, gas concentration was linked to changes in carbon structure, the effectiveness of our sensor was proven, a triple Gaussian model was developed to around gas production, and the impact of processing parameters on gas production was observed. With this Information a link between resulting carbon structure and gas content of the pyrolysis can be done and the changes in the pyrolysis environment were monitored in real time.

Biomass fast pyrolysis liquid (bio-oil) is a cellulose based alternative fuel with the potential to displace fossil fuels in stationary heat and power applications. To better understand the combustion behavior and emissions of bio-oil, a 10 kW spray burner was designed and constructed. The effect of swirl, atomization quality, ignition source (pilot) energy, air/fuel preheat and equivalence ratio on the stability and emissions of bio-oil spray flames was investigated. A blend of 80% pyrolysis liquid and 20% ethanol by volume was used during the tests and the results were compared to burner operation with diesel. It is important to have good atomization, thorough mixing and high swirl in order to stabilize ignition, promote the burnout of bio-oil and decrease CO, hydrocarbon and particulate matter emissions. The total amount of primary air and atomizing air that can be used to improve turbulence, mixing, droplet burnout and overall combustion quality is limited by the distillable fraction and narrow lean blow-out limit associated with pyrolysis liquid. Air and fuel preheat are important for reducing hydrocarbon and CO emissions, although subsequent fuel boiling should be avoided in order to maintain flame stability. The NOx produced in bio-oil flames is dominated by the conversion of fuel bound nitrogen. The particulate matter collected during bio-oil combustion is composed of both carbonaceous cenosphere residues and ash. Under good burning conditions, the majority consists of ash. Pilot flame energy and air/fuel preheat have a weak effect on the total particulate matter in the exhaust. Generally, these results suggest that available burner parameters can be adjusted in order to achieve low hydrocarbon, CO and carbonaceous particulate matter emissions when using pyrolysis liquid. Total particulates can be further mitigated by reducing the inherent ash content in bio-oil. Comparative burner tests with diesel reveal much lower emissions for this fuel at most of the operating points considered. This is due to the fully distillable nature, better atomization and improved spray ignition characteristics associated with diesel. Because of its superior volatility, diesel can also operate over a much wider range of primary air and atomizing air flow rates compared to bio-oil.

Biomass fast pyrolysis liquid (bio-oil) is a cellulose based alternative fuel with the potential to displace fossil fuels in stationary heat and power applications. To better understand the combustion behavior and emissions of bio-oil, a 10 kW spray burner was designed and constructed. The effect of swirl, atomization quality, ignition source (pilot) energy, air/fuel preheat and equivalence ratio on the stability and emissions of bio-oil spray flames was investigated. A blend of 80% pyrolysis liquid and 20% ethanol by volume was used during the tests and the results were compared to burner operation with diesel. It is important to have good atomization, thorough mixing and high swirl in order to stabilize ignition, promote the burnout of bio-oil and decrease CO, hydrocarbon and particulate matter emissions. The total amount of primary air and atomizing air that can be used to improve turbulence, mixing, droplet burnout and overall combustion quality is limited by the distillable fraction and narrow lean blow-out limit associated with pyrolysis liquid. Air and fuel preheat are important for reducing hydrocarbon and CO emissions, although subsequent fuel boiling should be avoided in order to maintain flame stability. The NOx produced in bio-oil flames is dominated by the conversion of fuel bound nitrogen. The particulate matter collected during bio-oil combustion is composed of both carbonaceous cenosphere residues and ash. Under good burning conditions, the majority consists of ash. Pilot flame energy and air/fuel preheat have a weak effect on the total particulate matter in the exhaust. Generally, these results suggest that available burner parameters can be adjusted in order to achieve low hydrocarbon, CO and carbonaceous particulate matter emissions when using pyrolysis liquid. Total particulates can be further mitigated by reducing the inherent ash content in bio-oil. Comparative burner tests with diesel reveal much lower emissions for this fuel at most of the operating points considered. This is due to the fully distillable nature, better atomization and improved spray ignition characteristics associated with diesel. Because of its superior volatility, diesel can also operate over a much wider range of primary air and atomizing air flow rates compared to bio-oil.

The significance of hydrogen production is increasing as fossil fuels are being depleted and energy security is of increasing importance to the United States. Furthermore, its production offers the potential to alleviate concerns regarding global warming and air pollution. In this thesis we focused on examining the efficiency of hydrogen production from current biomass compared to that from fossil fuel coal. We explored the efficiencies of maximum hydrogen production from biomass and from coal under current technology, namely coal gasification and biomass pyrolysis, together with following-up technologies such as steam reforming (SR). Bio-oil, product from pyrolysis and precursor for steam reforming, is hard to define. We proposed a simulation tool to estimate the pyrolytic bio-oil composition from various biomasses. The results helped us understand the accuracy that is needed for bio-oil composition prediction in the case it is converted to hydrogen. Hydrogen production is energy intensive. Therefore, heat integration is necessary to raise the overall thermodynamic efficiencies for both coal gasification and biomass pyrolysis. The results showed that considering the ultimate energy source, sunlight, about 6-fold more sunlight would be required for the coal to hydrogen than that for biomass to hydrogen. The main difference is in the efficiency of conversion of the ancient biomass to coal and therefore, for modern mankind, this loss has already been incurred.

Australia has the largest economical lignite resources in the world. However, the utilisation of lignite is faced with a number of technical, economical and environmental problems due to its high moisture content and some of the deposits containing high sulphur and high inorganic matter. During pyrolysis, the first step of any thermochemical conversion processes of coal, some of the sulphur in lignite evolves as sulphur-bearing volatiles while others are retained in the solid phase of the lignite char. The present research aims to study the sulphur transformation during pyrolysis of Australian lignite. The specific objectives of this research include a study on the transformation of pyrite, sulphate and organic sulphur during lignite pyrolysis as well as an investigation of the effect of inorganic matter on the sulphur transformation during lignite pyrolysis. To help the interpretation of sulphur transformation, the lignite samples were characterised using a combination of analytical techniques, i.e. X-ray diffraction (XRD), X-ray fluorescent (XRF), ion chromatography (IC), Scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infra red (FTIR), solid state 13C nuclear magnetic resonance (NMR) and petrographic analysis. Pyrolysis was carried out in a thermogravimetric analyser (TGA) and fixed bed reactor. The lignites and their chars were analysed for sulphur forms using a carbon sulphur (CS) analyser. To study the volatiles released during pyrolysis, experiments were also performed using a TGA coupled to a mass spectrometer (TGA-MS). Eleven (11) Australian lignite samples, denoted as L1 to L11, respectively, from the same lignite deposit but with different sulphur and inorganic matter concentrations were employed in this study. They are categorised as of low quality since they contain high Executive Summary Sulphur Transformation during Pyrolysis of an Australian Lignite v moisture, very high ash, low fixed carbon and thus they have low calorific value, except for L1. The lignites contain considerable amount of total sulphur, except for L1. Mineralogy of the lignites showed that the lignites contain extremely high sodium and chlorine. FTIR and solid state 13C NMR spectroscopy confirmed that oxygenated functional structures are significantly present in the lignites.