2,991 research outputs found

    Computational and experimental studies on the reaction mechanism of bio-oil components with additives for increased stability and fuel quality

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    As one of the world’s largest palm oil producers, Malaysia encountered a major disposal problem as vast amount of oil palm biomass wastes are produced. To overcome this problem, these biomass wastes can be liquefied into biofuel with fast pyrolysis technology. However, further upgradation of fast pyrolysis bio-oil via direct solvent addition was required to overcome it’s undesirable attributes. In addition, the high production cost of biofuels often hinders its commercialisation. Thus, the designed solvent-oil blend needs to achieve both fuel functionality and economic targets to be competitive with the conventional diesel fuel. In this thesis, a multi-stage computer-aided molecular design (CAMD) framework was employed for bio-oil solvent design. In the design problem, molecular signature descriptors were applied to accommodate different classes of property prediction models. However, the complexity of the CAMD problem increases as the height of signature increases due to the combinatorial nature of higher order signature. Thus, a consistency rule was developed reduce the size of the CAMD problem. The CAMD problem was then further extended to address the economic aspects via fuzzy multi-objective optimisation approach. Next, a rough-set based machine learning (RSML) model has been proposed to correlate the feedstock characterisation and pyrolysis condition with the pyrolysis bio-oil properties by generating decision rules. The generated decision rules were analysed from a scientific standpoint to identify the underlying patterns, while ensuring the rules were logical. The decision rules generated can be used to select optimal feedstock composition and pyrolysis condition to produce pyrolysis bio-oil of targeted fuel properties. Next, the results obtained from the computational approaches were verified through experimental study. The generated pyrolysis bio-oils were blended with the identified solvents at various mixing ratio. In addition, emulsification of the solvent-oil blend in diesel was also conducted with the help of surfactants. Lastly, potential extensions and prospective work for this study have been discuss in the later part of this thesis. To conclude, this thesis presented the combination of computational and experimental approaches in upgrading the fuel properties of pyrolysis bio-oil. As a result, high quality biofuel can be generated as a cleaner burning replacement for conventional diesel fuel

    Multi-objective scheduling of a steelmaking plant integrated with renewable energy sources and energy storage systems: Balancing costs, emissions and make-span

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    As an energy-intensive industry, the steel industry grapples with increasing energy costs and decarbonisation pressures. Therefore, multi-objective optimisation is widely applied in the production scheduling of the steelmaking plant. However, the optimal solution prioritising energy savings and emission reductions may lead to impractical or less economically efficient solutions, since the processing time requirement (PTR) of steel production orders in real-world production is neglected. This study fills the research gap by discussing the impact of PTR on the make-span of the steelmaking process and incorporating it into the optimisation model. Considering the variability of PTR, the solving of the multi-objective scheduling problem is transformed into the selection from Pareto solutions with different make-spans. To better leverage the temporal flexibility of the steelmaking process, a what-if-analysis-based strategy coupled with the Normal Boundary Intersection method is proposed to generate a series of evenly distributed Pareto solutions. The energy storage system is integrated to improve the time granularity of the steelmaking plant's flexibility. Our case studies demonstrate that the electricity and emission costs are reduced by 68.5%, indirect emissions are reduced by 83.5%, and the on-site renewable energy self-consumption rate increases by 12.1%. The effectiveness of the proposed method implies that it is of great relevance to the development of a cleaner steel industry in the future

    ANALISA KEANDALAN INSTRUMENTASI SCREENING MACHINE MENGGUNAKANMETODE RELIABILITY CENTERED MAINTENANCE (RCM) DI AREA PM-8 PT. INDAH KIAT PULP AND PAPER PERAWANG

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    ANALISA KEANDALAN INSTRUMENTASI SCREENING MACHINE MENGGUNAKAN METODE RELIABILITY CENTERED MAINTENANCE (RCM) DI AREA PM-8 PT. INDAH KIAT PULP AND PAPER PERAWANG DHORIFAH ADILAH 11750515213 Tanggal Sidang : 18 Januari 2023 Program Studi Teknik Elektro Fakultas Sains Dan Teknologi Universitas Islam Negeri Sultan Syarif Kasim Riau JL. HR. Soebrantas No. 155 Pekanbaru ABSTRAK PT. Indah Kiat Pulp and Paper merupakan perusahaan industri yang bergerak dibidang produksi pulp dan kertas yang berlokasi di Jalan Raya Minas-Perawang Km 26 Desa Perawang, Kecamatan Tualang Kabupaten Siak, Provinsi Riau. Terdapat beberapa unit proses pada perusahaan ini, salah satunya adalah Screening Machine unit ini terdapat pada proses pembuatan pulp yang berfungsi sebagai penyaringan pulp. Unit Screening Machine sering mengalami kegagalan yang menjadi salah satu penyebab kegagalannya yaitu sistem instrumentasi sehingga unit tidak berjalan optimal. Tujuan penelitian ini adalah untuk mengetahui penyebab dan potensi kegagalan yang mengakibatkan downtime pada screening machine serta menentukan waktu perawatan terhadap komponen instrumentasi yang kritis pada unit ini yaitu Diferential pressure transmitter, Consistency Transmitter, Electromagnetic Flow Meter, Level Transmitter, Control Valve Consistency, Vibration, dan Pressure Transmitter. Metode yang digunakan dalam penelitian ini adalah metode Realibility Centered Maintenance (RCM) yang dapat membantu memilih perawatan dan pemilihan tindakan perawatan dengan output berupa jadwal perawatan dan pihak yang bertanggung jawab. Hasil dari penelitian ini menyatakan Control Valve Consistency (336 hari kerja) memiliki nilai Resiko Priority Number (RPN) tertinggi sedangkan nilai RPN terendah terdapat pada komponen Electromagnetic Flow Meter (210 hari kerja). Kata Kunci: FMEA, Keandalan, Preventive Maintenance, RCM, Screening Machin

    Production and characterisation of pine wood powders from a multi-blade shaft mill

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    Wood is an important raw material for the manufacture of consumer products and in achieving societal goals for greater sustainability. Wood powders are feedstock for many biorefining and conversion techniques, including chemical, enzymatic and thermochemical processes and for composite manufacture, 3D printing and wood pellet production. Size reduction, therefore, is a key operation in wood utilisation and powder characteristics, such as shape, particle size distribution and micromorphology play a role in powder quality and end-use application. While in a green state, the native chemical composition and structure of wood are preserved. Powders are commonly produced from wood chips using impact mills, which require pre-sized, pre-screened and pre-dried chips. These steps necessitate repeated handling, intermediate storage and contribute to dry matter losses, operation-based emissions and the degradation of the wood chemistry.This thesis investigated a new size reduction technology, known as the multi-blade shaft mill (MBSM). The MBSM performance was studied through the milling of Scots pine (Pinus sylvestris L.) wood using a designed series of experiments and through modelling with multi-linear regression (MLR) analyses. Light microscopy combined with histochemical techniques were used to investigate particle micromorphology and distribution of native extractives in powders. The aim was to evaluate the technical performance of the MBSM with relation to operational parameters, to characterise the produced powders and to evaluate the technology through comparison with impact milling.The results showed that the MBSM could effectively mill both green and dry wood. Produced powders showed distinct differences compared to those obtained using a hammer mill (HM). The specific milling energy of the MBSM was lowest for green wood and within the range of other established size reduction technologies. However, much narrower particle size distributions were observed in MBSM powders and they had significantly greater amounts of finer particles. Particles with high aspect ratio and sphericity were a characteristic of MBSM powders and this Production and characterisation of pine wood powders from a multi-blade shaft mill was true for wood milled above and below its fibre saturation point. MBSM powders from green wood showed evidence of higher specific surface area, larger pore volume and greater micropore diameter than those from HM powder. Preliminary microscopic examination suggested that cell walls in MBSM powders showed evidence of retaining their original native wood structure. Consequently, their extractive content appeared intact. This was in contrast to HM powder and it may reflect the differences between the two size reduction mechanisms. According to the produced MLR models, the results suggest that MBSM milling is more akin to a sawing process and opposite to that of impact-based mills

    Science and Innovations for Food Systems Transformation

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    This Open Access book compiles the findings of the Scientific Group of the United Nations Food Systems Summit 2021 and its research partners. The Scientific Group was an independent group of 28 food systems scientists from all over the world with a mandate from the Deputy Secretary-General of the United Nations. The chapters provide science- and research-based, state-of-the-art, solution-oriented knowledge and evidence to inform the transformation of contemporary food systems in order to achieve more sustainable, equitable and resilient systems
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