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  • 1. Aziz, M.
    et al.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Production of hydrogen from algae: Integrated gasification and chemical looping2017In: Proceedings of the 9th International Conference on Applied Energy, Elsevier, 2017, Vol. 142, p. 210-215Conference paper (Refereed)
    Abstract [en]

    Due to their high potential and beneficial characteristics, algae is considered as very promising energy source in future. In this study, an integrated conversion system of algae to hydrogen is proposed with the objective of high total energy conversion efficiency. The proposed system mainly covers algal drying, gasification, and chemical looping. To facilitate optimum heat circulation throughout the proposed system, enhanced process integration is adopted. It combines exergy recovery and process integration technologies in order to achieve a wasted energy, hence the total energy efficiency can be improved significantly. In the proposed system, to convert algae to hydrogen, steam gasification and syngas chemical looping are integrated as the main conversion. Iron oxide is employed as the oxygen carrier, and is circulated among the reactors in the chemical looping module. Process modeling and calculation is performed using ASPEN Plus, and the total energy efficiency, including hydrogen production and power generation, is evaluated. Several operating parameters including target moisture content in drying, steam-to-biomass ratio in gasification, and chemical looping pressure, are observed. From the results, it is shown that the proposed system is potential to convert algae to hydrogen with high total energy efficiency, which is higher than 70%. Both target moisture content and steam-to-biomass ratio influence strongly the total energy efficiency. On the other hand, chemical looping pressure show insignificant effect to total energy efficiency.

  • 2. Budiman, B. A.
    et al.
    Juangsa, F. B.
    Aziz, M.
    Nurprasetio, I. P.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Experimental verification of interfacial strength effect on the mechanical properties of carbon fiber-epoxy composite2017In: International Journal on Advanced Science, Engineering and Information Technology, ISSN 2088-5334, E-ISSN 2460-6952, Vol. 7, no 6, p. 2226-2231Article in journal (Refereed)
    Abstract [en]

    The effects of carbon fiber-epoxy interfacial strength on the mechanical properties of the corresponding fiber-matrix composites are experimentally demonstrated in this work. Two composites containing different carbon fibers were tested: as-received fibers and fibers soaked in acetone to remove adhesive on their surfaces. The fiber surfaces were first characterized by scanning electron microscopy and time-of-flight secondary-ion mass spectrometry to verify removal of the adhesive. Further, single-fiber fragmentation tests were conducted to evaluate the fiber strength and the interfacial strength. The mechanical properties of the composites were evaluated via tensile testing under longitudinal and transverse loadings. The results show that interfacial strength does not decrease the mechanical properties of the composites under longitudinal loading. In contrast, under transverse loading, the interfacial strength significantly decreases the mechanical properties, specifically the ultimate tensile strength and toughness of the composites.

  • 3. Gomez, R. Y.
    et al.
    Nuran, Zaini Ilam
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Helsen, L.
    Landfill solid waste-based syngas purification by a hybrid pulsed corona plasma unit2019In: European Biomass Conference and Exhibition Proceedings, ETA-Florence Renewable Energies , 2019, p. 520-522Conference paper (Refereed)
    Abstract [en]

    Gasification of excavated Municipal Solid Waste (MSW) for energy and materials recovery has been seen as a solution for current energetic, environmental and land availability issues. However, it poses many technological challenges, and among them the most difficult is to obtain of a tar-free syngas. In this work, two set of experiments were performed in order to obtain a syngas from MSW with a low tar content. In the first stage, MSW gasification was performed in order to identify the tar yield and composition at different temperatures using air and steam. After that, the most representative tar compound, naphthalene, was selected to perform tar cracking experiments in a pulsed corona plasma reactor able to operate from ambient temperature up to 1200ᵒC. The results of these experiments show that the pulsed corona plasma can enhance the tar thermal cracking reactions, reducing by 200ᵒC the temperature at which 100% of the naphthalene is converted.

  • 4. Nurdiawati, A.
    et al.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Aziz, M.
    Dual-stage chemical looping of microalgae for methanol production with negative-carbon emission2019In: Innovative Solutions for Energy Transitions, Elsevier, 2019, Vol. 158, p. 842-847Conference paper (Refereed)
    Abstract [en]

    As the world is transitioning towards a low-carbon economy, it is becoming important to develop ways to reduce carbon dioxide (CO2) emissions. Chemical looping, a low carbon technology for the industry, is considered as a potential breakthrough technology and a viable option for efficient fuel conversion and carbon capture and storage, with the successful completion of pilot plant trials in the USA. The conversion of captured CO2 to methanol can be considered a promising method for significantly reducing CO2 emissions, while the produced methanol can be used as a convenient energy carrier for hydrogen storage. This study focuses on a process of converting microalgae, a potential fuel feedstock, into methanol by utilizing CO2 generated within the process. The specific focus lies on the conversion of the microalgae into methanol through dual-stage chemical looping and efficient process integration with maximum energy recovery. Aspen Plus® was used to simulate the facility producing 42 mt (metric tons) methanol/h using 60.1 mt/h CO2 and 8.2 mt/h H2. The process was divided into four-module operations: drying, chemical looping gasification, syngas chemical looping, and methanol synthesis. The energy efficiency of this process is around 45-51% which is comparative with the concentrated CO2-based methanol and typical biomass-based syngas to methanol processes. Because the separated CO2 obtained via chemical looping is utilized for methanol synthesis, the carbon-negative value is attained.

  • 5.
    Nurdiawati, A.
    et al.
    Japan.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Aziz, M.
    Japan.
    Efficient hydrogen production from algae and its conversion to methylcyclohexane2018In: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 70, p. 1507-1512Article in journal (Refereed)
    Abstract [en]

    Herein, the supercritical water gasification (SCWG) of microalgae combined with syngas chemical looping (SCL) for H2 production and storage employing liquid organic H2 carrier (LOHC) system have been proposed and analysed in terms of energy efficiency. Microalgae are converted to syngas in the SCWG module and then introduced into the SCL module to produce high-purity of H2 and a separated CO2 stream. H2 storage is achieved via the hydrogenation reaction using toluene to produce methylcyclohexane (MCH). The heat released from the exothermic hydrogenation reaction is exploited to generate steam for sustaining the SCWG reaction. Simulations were performed using Aspen Plus™ considering the feed concentration and SCWG temperature as the system variables. The simulation results show that the SCWG reaction can be energetically self-sustained using the proposed configuration. Based on the process modelling and calculations, the proposed integrated system exhibited of approximately 13.3 %, 42.5 %, and 55.8 % for power generation, H2 production, and total energy efficiency.

  • 6.
    Nurdiawati, Anissa
    et al.
    Tokyo Inst Technol, Dept Transdisciplinary Sci & Engn, Meguro Ku, 2-12-1 Ookayama, Tokyo 1528550, Japan..
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Irhamna, Adrian Rizqi
    Inst Teknol Bandung, Fac Mech & Aerosp Engn, Ganesha 10, Bandung 40132, Indonesia..
    Sasongko, Dwiwahju
    Inst Teknol Bandung, Dept Chem Engn, Ganesha 10, Bandung 40132, Indonesia..
    Aziz, Muhammad
    Univ Tokyo, Inst Ind Sci, Meguro Ku, 4-6-1 Kornaba, Tokyo 1538505, Japan..
    Novel configuration of supercritical water gasification and chemical looping for highly-efficient hydrogen production from microalgae2019In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 112, p. 369-381Article in journal (Refereed)
    Abstract [en]

    This study proposes a novel system to efficiently produce hydrogen from microalgae, based on supercritical water gasification and syngas chemical looping, and its conversion to methylcyclohexane. The process consists of a gasifier, a syngas chemical looping reactor, and a methylcyclohexane synthesis reactor as the main units. Microalgae are converted to syngas in the supercritical water gasification reactor. Thereafter, the produced syngas is introduced into the syngas chemical looping module to produce pure hydrogen and a separated carbon dioxide stream. The hydrogen is then reacted with toluene through the hydrogenation reaction to produce methylcyclohexane as a hydrogen carrier. The heat released from the methylcyclohexane synthesis module and chemical looping combustor is utilized to sustain the thermal balance of the supercritical water gasification unit. The system performance is observed under different feed moisture contents, operating temperatures in the supercritical water gasification unit, and operating pressures in the syngas chemical looping unit. A steady-state process simulation of Aspen Plus software is used for this purpose. The proposed integrated system exhibits of approximately 13.7%, 45.3%, and 59.1% for power generation efficiency, hydrogen production efficiency, and total energy efficiency, which demonstrates an efficient process of hydrogen production. The preliminary economic assessment shows that more than half of the operating cost accounts for microalgae production. This indicates the microalgae feedstock is one of the critical cost drivers in the microalgae-to-hydrogen production system.

  • 7.
    Salem, A. M.
    et al.
    Mechanical Power Department, Faculty of Engineering, Tanta University, Egypt. Systems, Power and Energy Research Division, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Paul, M. C.
    Systems, Power and Energy Research Division, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The evolution and formation of tar species in a downdraft gasifier: Numerical modelling and experimental validation2019In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 130, article id 105377Article in journal (Refereed)
    Abstract [en]

    Gasification is one of the most important methods for converting biomass to syngas currently used in energy production. However, tar content in syngas limits its direct use and thus requires additional removal techniques. The modelling of tar formation, conversion and destruction along a gasifier could give a wider understanding of the process and subsequently help in tar elimination and reduction. However, tar complexity, which contains hundreds of species, makes the modelling process hard and computationally intensive, because the chemistry of the formation and the combustion of many species have not yet been fully studied. In this work, a detailed kinetic model for the evolution and formation of tar from downdraft gasifiers, for the first-time, was built. The model incorporates four main tar species (benzene, naphthalene, toluene, and phenol) with a total of eighteen different kinetic reactions implemented in the code for every zone. Experimental work was carried out to initially validate the results of the kinetic code and found a good agreement. Further experiments were conducted at three different equivalence ratios (ERs) and at three different temperatures (800, 900, and 1100 °C). Sensitivity analysis was then carried out by the kinetic code to optimise the working parameters of a downdraft gasifier that led to a higher calorific value of syngas. The results reveal that a tar evolution model is more accurate for wood biomass materials and that using ER around 0.3, and moisture content levels lower than 10% lead to the production of higher value syngas with lower tar amounts.

  • 8.
    Sophonrat, Nanta
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sandström, L.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Stepwise pyrolysis of mixed plastics and paper for separation of oxygenated and hydrocarbon condensates2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 229, p. 314-325Article in journal (Refereed)
    Abstract [en]

    Mixed plastics and papers are two of the main fractions in municipal solid waste which is a critical environmental issue today. Recovering energy and chemicals from this waste stream by pyrolysis is one of the favorable options to achieve a circular economy. While pyrolysis products from plastics are mainly hydrocarbons, pyrolysis products from paper/biomass are highly oxygenated. The different nature of the two pyrolysis products results in different treatments and applications as well as economic values. Therefore, separation of these two products by multi-step pyrolysis based on their different decomposition temperatures could be beneficial for downstream processes to recover materials, chemicals and/or energy. In this work, stepwise pyrolysis of mixed plastics and paper waste was performed in a batch type fixed bed reactor using two different pyrolysis temperatures. Neat plastic materials (polystyrene, polyethylene) and cellulose mixtures were used as starting materials. Then, the same conditions were applied to a mixed plastics and paper residue stream derived from paper recycling process. The condensable products were analyzed by GC/MS. It was found that pyrolysis temperatures during the first and second step of 350 and 500 °C resulted in a better separation of the oxygenated and hydrocarbon condensates than when a lower pyrolysis temperature (300 °C) was used in the first step. The products from the first step were derived from cellulose with some heavy fraction of styrene oligomers, while the products from the second step were mainly hydrocarbons derived from polystyrene and polyethylene. This thus shows that stepwise pyrolysis can separate the products from these materials, although with some degree of overlapping products. Indications of interaction between PS and cellulose during stepwise pyrolysis were observed including an increase in char yield, a decrease in liquid yield from the first temperature step and changes in liquid composition, compared to stepwise pyrolysis of the two materials separately. A longer vapor residence time in the second step was found to help reducing the amount of wax derived from polyethylene. Results from stepwise pyrolysis of a real waste showed that oxygenated and acidic products were concentrated in the liquid from the first step, while the product from the second step contained a high portion of hydrocarbons and had a low acid number. 

  • 9.
    Zaini, Ilman Nuran
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Lopez, Cristina Garcia
    Rhein Westfal TH Aachen, Dept Proc & Recycling IAR, D-52060 Aachen, Germany..
    Pretz, Thomas
    Rhein Westfal TH Aachen, Dept Proc & Recycling IAR, D-52060 Aachen, Germany..
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Characterization of pyrolysis products of high-ash excavated-waste and its char gasification reactivity and kinetics under a steam atmosphere2019In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 97, p. 149-163Article in journal (Refereed)
    Abstract [en]

    The focus of this study is the pyrolysis and gasification of Refuse Derived Fuel (RDF) and fine fractions recovered from the excavation of landfill waste, with an emphasize on the characterization of the reactivity and kinetics of the char-steam gasification. The results from the pyrolysis tests demonstrated that CO and CO2 are the main produced gases during the pyrolysis of the finer fraction of landfill waste. This might be caused by the accumulation of degraded organic materials. The oil products from the pyrolysis of landfill waste were dominated by the derivative products of plastics such as styrene, toluene, and ethylbenzene. The chars obtained from the pyrolysis process were gasified under steam and steam/air atmospheres at temperatures between 800 and 900 degrees C by using thermogravimetry. The results from the gasification tests demonstrated that the char reactivity was mainly affected by the amount ratio between catalytic elements (K, Ca, Na, Mg, and Fe) over the inhibitor elements (Si, Al, and Cl), as well as the ash amount in the char. The results showed that char from the fine fraction of landfill waste has a higher reactivity than the RDF fraction, due to the high content of catalytic metal elements. These results suggest the use of a smaller sieve opening size for landfill waste separation processes may produce waste fuels with a high reactivity during gasification. Further, based on the thermogravimetric data, the kinetic parameters of landfill waste char gasification were calculated to have activation energies ranging from 54 to 128 kJ/mol. Author(s). Published by Elsevier Ltd.

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