| 1. |
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| 2. |
- Bolívar Caballero, José Juan, et al.
(författare)
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Advanced application of a geometry-enhanced 3D-printed catalytic reformer for syngas production
- 2023
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 287
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Tidskriftsartikel (refereegranskat)abstract
- Catalyst research on reforming processes for syngas production has mainly focused on the active metals and support materials, while the effect of the catalyst's geometry on the reforming reactions has been poorly studied. The application of 3D-printed materials with enhanced geometries has recently started to be studied in heterogeneous catalysis and is of interest to be implemented for reforming biomass and plastic waste to produce H2-rich syngas. In this study, a geometry-enhanced 3D-printed Ni/Al2O3/FeCrAl-based monolithic catalyst with a periodic open cellular structure (POCS) was designed and fabricated. The catalyst was used for batch steam reforming biomass pyrolysis volatiles for syngas production at different parameters (temperature and steam-to-carbon ratio). The results showed complete reforming of pyrolysis volatiles in all experimental cases, a high H2 yield of ≈ 7.6 wt% of biomass was obtained at the optimized steam-to-carbon ratio of 8 and a reforming temperature of 800 °C, which is a higher yield compared to other batch reforming tests reported in the literature. Moreover, CFD simulation results in COMSOL Multiphysics demonstrated that the POCS configuration improves the reforming of pyrolysis volatiles for tar/bio-oil reforming and H2 production thanks to enhanced mass and heat transfer properties compared to the regular monolithic single-channel configuration.
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| 3. |
- Jagodzińska, Katarzyna, 1990-, et al.
(författare)
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Pyrolysis of excavated waste from landfill mining: Characterisation of the process products
- 2021
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Ingår i: Journal of Cleaner Production. - The Netherlands : Elsevier BV. - 0959-6526 .- 1879-1786. ; 279
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Tidskriftsartikel (refereegranskat)abstract
- The current transition to a circular economy model laid the foundations for the development of the Enhanced Landfill Mining concept. Hitherto, a few studies have been performed on the thermochemical valorisation of excavated waste, of which a majority concern incineration or gasification. Nonetheless, no previous studies on excavated waste pyrolysis, including the characterisation of the process products, have been identified. Ergo, this study aims at filling this knowledge gap. The pyrolysis of refuse-derived fuel formed from excavated waste was performed in a lab-scale reactor in the temperature range of 400–700 °C. The non-condensable products (non-condensables) were analysed using Micro GC, whereas the condensable products (condensables) were characterised using GC/MS. Additionally, the distribution of C, H, N, S, O, and Cl among the process products was analysed. The high content of C2–C3 hydrocarbons was detected in non-condensables, whereas the abundance of polycyclic aromatic hydrocarbons (PAHs) was detected among condensable products. However, due to feedstock complex thermal decomposition pattern, no overall tendency, covering the process product properties in relation to the process temperature, can be determined. These fluctuations of composition, therefore, have to be taken into account in the planning of the future utilisation of the excavated waste pyrolysis products. Moreover, two possible risks, connected with the further process products utilisation, were identified – namely, chlorine forming primarily organic compounds and sulphur forming mostly gaseous compounds (H2S).
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| 4. |
- Persson, Henry, et al.
(författare)
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Production of renewable aromatic hydrocarbons by ex-situ catalytic fast pyrolysis of biomass in a combined fluidized bed and fixed bed reactor system
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- An ex-situ catalytic fast pyrolysis lab-scale setup consisting of a fluidized bed pyrolyzer and a fixed bed catalytic reactor was experimentally evaluated. The effect of weight hourly space velocity was investigated in the range of 0.35-0.77 h-1 during 260 min of operation. A lower biomass feed rate over a fixed amount of catalyst results in a higher degree of vapor deoxygenation (from 71 to 79.5 wt%) as well as higher concentrations of aromatic hydrocarbons. The carbon conversion from biomass to upgraded liquids is negatively correlated with the aromatic concentrations. Online gas analysis present no significant changes in the catalytic performance during the operational time. The results of this study indicate that the difference in liquid deoxygenation observed when varying the biomass feed rate is dependent on the vapor concentration in the gas stream over the catalytic bed rather than being significantly affected by catalyst deactivation during operation.
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| 5. |
- Persson, Henry, et al.
(författare)
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Two-step pyrolysis of biomass to enhance the chemical stability of pyrolytic liquids
- 2017
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Ingår i: European Biomass Conference and Exhibition Proceedings 2017. - : ETA-Florence Renewable Energies. ; , s. 1186-1189
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Konferensbidrag (refereegranskat)abstract
- Aging of pyrolytic liquid during storage changes its chemical and physical properties. The reason for aging is the chemical instability of the liquid, which is not at thermodynamic equilibrium when quenched after pyrolysis. Compounds active in these reactions mainly derivatives from hemicellulose (e.g. acids and carbonyls). In this work, a two-step pyrolysis concept was investigated to separate these compounds in a lower temperature treatment step upstream a conventional pyrolyzer. Different temperatures of the lower temperature treatment was investigated with constant conditions of the conventional treatment. The total liquid yield derived did not vary from pyrolysis in one step. Results show that the two-step pyrolysis process significantly reduces the concentration of organic acids and carbonyls in the liquid product from the second pyrolyzer, which instead are found in the liquid from the lower temperature treatment. Also, the concentration of sugar derivatives from the second step treatment is increased with the temperature of the first step. However, a complete separation of aging active compounds is not possible without sacrificing partial fractions of others (lignin derivatives were found in the low-temperature treatment). By varying the temperature of the first step one can control the concentrations and the liquid yield from each step.
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| 6. |
- Shi, Ziyi, et al.
(författare)
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Continuous catalytic pyrolysis of biomass using a fluidized bed with commercial-ready catalysts for scale-up
- 2023
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 273
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Tidskriftsartikel (refereegranskat)abstract
- The use of catalytic fast pyrolysis (CFP) of biomass to produce high-quality bio-oils as potential substitutes for conventional fuels plays an essential role in the decarbonization of the world. In this study, continuous CFP tests of sawdust using three commercial-ready catalysts were performed. The overall objective is to screen appropriate catalysts and catalyst loading amounts for further commercialization and upgrading by evaluating the quality of the organic fraction bio-oils and clarifying the relationship between the hydrogen-to-carbon atomic effective (H/Ceff) ratio and bio-oil yield. The results displayed that, owing to a cracking effect of the catalyst, all catalytic cases had higher H/Ceff ratios and larger relative area percentages of hydrocarbons determined by NMR. Thermogravimetric analysis reveals that, compared to non-catalytic bio-oils, catalytic bio-oils showed more distillates in the diesel range. Increasing the catalyst-loading amount also showed the same effect. Overall, all bio-oil products from catalytic cases had H/Ceff ratios higher than 0.6, indicating the production of promising oil for hydrodeoxygenation. By analyzing and fitting the data from this work and comparing with the literature, it could be concluded that its yield would decrease as the bio-oil product quality increases (the H/Ceff ratios increase). © 2023 The Authors
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| 7. |
- Sophonrat, Nanta, et al.
(författare)
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Ex Situ Catalytic Pyrolysis of a Mixture of Polyvinyl Chloride and Cellulose Using Calcium Oxide for HCl Adsorption and Catalytic Reforming of the Pyrolysis Products
- 2019
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society. - 0888-5885 .- 1520-5045. ; 58:31, s. 13960-13970
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Tidskriftsartikel (refereegranskat)abstract
- In the context of chemical recycling of mixed plastics and paper, multitemperature step pyrolysis has shown good potential for the separation of oxygenated products from hydrocarbons. Here, we report results of an investigation of the first pyrolysis step at low temperature, which involves the dehydrochlorination of polyvinyl chloride (PVC) and the pyrolysis of cellulose, the main component of paper. Calcium oxide (CaO), selected for its chloride adsorption ability and its catalytic activity on biooil deoxygenation, was used for upgrading the downstream products from the pyrolysis. Additionally, we studied the performance of CaO for the simultaneous adsorption of HCl and for reforming cellulose pyrolysates in the temperature range of 300-600 °C with feedstock to CaO ratios of 1:0.2, 1:0.4, and 1:1. It was found that the suitable catalytic temperature for HCl and acetic acid adsorption is lower than 400 °C. This is due to the desorption of HCl from CaCl2 and Ca(OH)Cl in the presence of water and CO2 at 400 °C and higher. A larger amount of CaO resulted in a more efficient reduction of acids and the organic liquids were found to have lower amounts of oxygen. A comparison between the cases of neat and mixed feedstock showed that pyrolysis of mixed feedstock produced more water, H2, CO, and polycyclic aromatic hydrocarbons (PAHs) when compared to the case of neat materials over CaO
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| 8. |
- Sophonrat, Nanta, et al.
(författare)
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Ex-situ catalytic pyrolysis of a mixture of PVC and cellulose using calcium oxide for HCl adsorption and catalytic reforming of the pyrolysis products
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In the context of chemical recycling of mixed plastics and paper, multi-temperature step pyrolysis has shown good potential for the separation of oxygenated products from hydrocarbons. Here, we report results of an investigation of the first pyrolysis step at low temperature, which involves the dehydrochlorination of polyvinyl chloride (PVC) and the pyrolysis of cellulose—the main component of paper. Calcium oxide (CaO), selected for its chloride adsorption ability and its catalytic activity on biooil deoxygenation, was used for upgrading the downstream products from the pyrolysis. Additionally, we studied the performance of CaO for the simultaneous adsorption of HCl and for reforming cellulose pyrolysates in the temperature range of 300-600 °C with feedstock to CaO ratios of 1:0.2, 1:0.4 and 1:1. It was found that the suitable catalytic temperature for HCl and acetic acid adsorption is lower than 400 °C. This is due to the reaction of CaO with water that causes the desorption of HCl at temperatures above 400 °C. A larger amount of CaO resulted in a more efficient reduction of acids and the organic liquids were found to have lower amounts of oxygen. A comparison between the cases of neat and mixed feedstock showed that pyrolysis of mixed feedstock produced more water, H2, CO and polycyclic aromatic hydrocarbons (PAHs) when compared to the case of neat materials over CaO.
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| 9. |
- Svanberg, Andreas
(författare)
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Full-Scale Modelling and Simulation of Bucket Filling and Wear for Mining Rope Shovels
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Handling of granular material occurs all over the world for different reasons and under different conditions. In the mining industry, granular material handling is present in almost all processes. The machinery that deals with the granular material is typically subjected to significant wear. The loading process is a very crucial task in any mine. During the loading process, fragmented material is loaded with large rope- or hydraulic shovels. In open-pit mines, machines capable of loading more than 100 tonnes of fragmented rocks per bucket are often used. Maximizing the availability and increasing the productivity of these enormous machines are two challenges that are crucial in order to maintain the production.The work in this thesis is divided up into two parts, where the first part is to develop a numerical model to simulate granular material handling for full-scale applications, and the second part is to develop a wear model suitable for the prediction of abrasive sliding and impact wear for full-scale industrial use. A numerical model utilizing the discrete element method (DEM) in combination with rigid-finite element (FE) is used to obtain a realistic granular material model of copper ore. A multi rigid body dynamics model is utilized to model a realistic dynamic model of a rope shovel. Novel full-scale in-situ experiments are used for calibration and validation of the granular material model. A wear model, with the basis of the traditional Finnie's wear model is developed. The model enables the calculation of wear for different impact angles varying between sliding to vertical impacts. Calibration of the wear model is performed by measuring the wear on steel plates belonging to a vibratory feeder. A sensitivity analysis is performed to investigate how the particle size distribution (PSD) and the FE grid size influences the numerical wear. Furthermore, the model is validated by comparing predicted wear from simulations with experimentally measured wear on a rope shovel bucket.Validation of the granular material model from drone video recordings, and measurements of mass in the bucket confirms that the granular material model is able to capture the main phenomenon during the loading process. Validation of the wear simulation model agrees exceptionally well between the predicted wear when compared to the experimentally obtained wear data. In conclusion, numerical models including prediction of wear are developed and demonstrated for the loading process. Calibration and validation approaches for full-scale industrial use are also presented. The presented model can be used as a tool for industries to make better decisions regarding e.g. how to increase productivity and reduce wear.
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| 10. |
- Svanberg, Andreas, et al.
(författare)
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Full-scale simulation and validation of bucket filling for a mining rope shovel by using a combined rigid FE-DEM granular material model
- 2021
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Ingår i: Computational Particle Mechanics. - : Springer. - 2196-4386 .- 2196-4378. ; 8, s. 825-843
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Tidskriftsartikel (refereegranskat)abstract
- Rope shovels and other heavy mining equipment used for loading fragmented rocks to extract minerals from the earth are used in almost every open pit mine. The optimization of the loading process is of enormous value due to the extremely large amount of material turn over. In this work, a full-scale numerical model of the loading process is developed. Granular material of copper ore is modeled in a combination of rigid finite elements for larger particles with complex shapes, and the discrete element method for smaller particles. A multi rigid body dynamic model, discretized with finite elements are used to model the rope shovel. Calibration of the numerical model for the granular material is performed via a new and unique experimental full-scale approach of analyzing waste rock pile angles with a height of approximately 15 m. In situ experimental data acquisition is performed during the loading process for validation of the model. After model validation, the influence of several loading variables such as bucket rake angle, velocity, and position from the pile are investigated and evaluated. When comparing the numerical model results with experimental mass measurement an excellent agreement was observed. Also, drone camera video recordings of the mass flow behavior and the numerical mass flow behavior are in agreement. Small adjustments of dig variables show a significant effect on the average dig force as well as the bucket fill factor.
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| 11. |
- Svanberg, Andreas, et al.
(författare)
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Full-Scale Simulation and Validation of Wear for a Mining Rope Shovel Bucket
- 2021
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Ingår i: Minerals. - : MDPI. - 2075-163X. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- Failure in industrial processes is often related to wear and can cause significant problems. It is estimated that approximately 1–4% of the gross national product for an industrialized nation is related to abrasive wear. This work aims to numerically predict development of wear for full-scale mining applications in harsh sub-arctic conditions. The purpose is to increase the understanding of wear development in industrial processes and optimize service life and minimize costs related to wear. In the present paper, a granular material model consisting of the discrete element method (DEM) and rigid finite element particles is utilized to study wear in full-scale mining applications where granular materials and steel structures are present. A wear model with the basis in Finnie’s wear model is developed to calculate wear from combined abrasive sliding and impact wear. Novel in situ full-scale experiments are presented for calibration of the wear model. A simulation model of the rope shovel loading process is set up where the bucket filling process is simulated several times, and the wear is calculated with the calibrated wear model. From the full-scale validation, it is shown that the simulated wear is in excellent agreement when compared to the experiments, both regarding wear locations and magnitudes. After validation, the model is utilized to study if wear can be minimized by making small changes to the bucket. One major conclusion from the work is that the presented wear simulator is a suitable tool that can be used for product development and optimization of the loading process.
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| 12. |
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| 14. |
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| 15. |
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| 16. |
- Svanberg, Christer, 1970, et al.
(författare)
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Secondary relaxation in confined and bulk propylene carbonate
- 2003
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Ingår i: Europhysics Letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 64:3, s. 358-363
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Tidskriftsartikel (refereegranskat)abstract
- Dielectric loss spectra of propylene carbonate in bulk and dissolved in a polymer matrix are investigated with focus on the currently debated excess wing. The spatial restrictions caused by the polymer matrix slow down the main structural (α) relaxation, while the excess wing continuously transforms towards a shoulder with increasing spatial restrictions. We show that the excess wing in a consistent manner can be described by a secondary relaxation with only a weak dependence of the concentration of polymer. Thus the results imply that the excess wing is due to a secondary relaxation submerged in the α-relaxation.
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| 17. |
- Zaini, Ilman Nuran, et al.
(författare)
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A pilot-scale test of plasma torch application for decarbonising the steel reheating furnaces
- 2023
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Ingår i: THERMAL SCIENCE AND ENGINEERING PROGRESS. - : Elsevier BV. - 2451-9049. ; 40
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Tidskriftsartikel (refereegranskat)abstract
- The decarbonisation of the Swedish iron and steel industry is crucial in achieving Sweden's target to achieve zero net emissions of greenhouse gases (GHG) by 2045. Direct electrification of industrial furnaces could be an important milestone in decarbonising the iron and steel plants. In this study, pilot-scale trials were performed to investigate the possibility of plasma torch application for steel reheating furnaces. A 250 kW DC plasma torch was used to heat the furnace from room to the operating temperature of 1200 degrees C. Different plasma carrier gases were then used to study their impact on the plasma torch efficiency, furnace temperature profile, NOX emission, and steel oxidation. The results show that the furnace could be heated at a relatively uniform temperature and reasonable time. The combination of air and LPG in the plasma generator provides the most uniform temperature distribution and highest plasma torch efficiency, but it generates the highest NOX emission. N2 as plasma gas resulted in notably poorer temperature distribution and lower plasma torch efficiency; however, it can suppress the oxide formations. Meanwhile, CO2 as plasma gas could be a promising option among the studied gas mixtures as it can provide a good heating performance with a low NOX formation. In summary, the current study has proved that it is practical and functionally possible to heat steel using plasma technology.
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