中国四川省北東部における伝統的住居の外皮に対するパッシブ省エネ戦略の最適化と技術及び経済性評価

This study aims to determine some efficient and economic strategies for traditional dwellings in northeast of Sichuan hills, China to lower their energy demand. In addition, energy-saving effects and economic performance need to be simultaneously assessed, therefore we carried out the thorough works on tech-economic evaluation of each energy-saving strategy. Eventually, we obtain a set of effective and economic energy-saving strategies and the research results can provide valuable references for decision-makers to select appropriate energy-saving strategies to reduce the energy demand of traditional dwellings, lower the economic burden for renovation and save more money. The significance of this study is to determine the optimal parameters for each energy-saving strategy, and propose the most economic retrofit strategy for traditional dwellings in this region. Results can help residents and decision-makers select the relatively appropriate energy-saving strategy to retrofit traditional dwellings in this region, and thereby decrease the energy demand of the building.北九州市立大

Reverse Flotation

Reverse flotation of coal can be explained as a process where valuable minerals are depressed, while undesired and unhealthy minerals are floated with the help of some reagents. Nowadays, conventional enrichment method of coal could not achieve removing unhealthy minerals partially from internal structure of coal such as sulfur, Hg, Au, which propagate in air after burning treatment, or heavy metals such as Be, Cr, Ni, As, Cd, Co, Ni, Sb, Se, Pb, Co, Cl, Be, Ba, which involve in water and soil where habitat and human health can directly be influenced from them. In fact, reverse flotation of coal enables to remove these undesired mineral content from coal structure not only in macro size but also in micro size. On the other hand, like undesired minerals, valuable ones like vanadium, germanium, etc. are also taken from coal particles by using the same procedure. Thus, with all these respect, reverse flotation is considered as an alternative and innovative solution for coal beneficiation especially for low rank coal since low rank coal is more compatible for reverse flotation because of being more hydrophilic which means tendency to float is less. Around the world wide, most of the coal reserves belong to low rank coal, so application of reverse flotation is becoming more inevitably common in future

An Evaluation of Economic Potential Solar Photovoltaic Farm in Thailand: Case study of Polycrystalline Silicon and Amorphous Silicon Thin Film

Solar energy in Thailand plays an important role to achieve the target of the Alternative Energy Development Plan (AEDP). Enormous investments from investors are expected to occur for support AEDP. Therefore, the objective of this study was to evaluate and compare the economic potential of solar PV farm between polycrystalline silicon (PCSS) and amorphous silicon thin film (ASTF) type. Questionnaires submitted to private solar PV farm for collecting data. As a result, four main investment costs of PSS are identified: (1) photovoltaic module; (2) connection system; (3) inverter, and (4) engineering construction, distributed as 58.09%, 19.66%, 12.96%, and 4.47%, respectively. The financial analysis found that Payback period (PB), Internal Rate of Return (IRR), and Solar Plant capital of ASTF were less than PCSS; however, it returns low income along 25 years than PCSS. It could be suggested that the investment on PCSS is worth than ASTF. Keywords: Economic potential, Solar PV farm, Investment, Financial economic. JEL Classifications: C8, G0, M

Desulphurisation of fine coal waste tailings using algal lipids

The South African economy is an energy-driven economy which relies on coal to meet most of its energy demands. Coal mining has resulted in the generation of coal waste over 60 million tonnes, annually. Apart from the huge footprint of this waste, the sulphide minerals contained in the waste have resulted in the generation of acid rock drainage (ARD). A lot of techniques have been developed to prevent and mitigate ARD, however most of these techniques have fallen short in terms of meeting their desired objectives due to the long-term nature of ARD generation which can persist for hundreds of years after mine closure. This has resulted in emphasis being put on long-term prevention techniques that remove ARD risk over treatment techniques. One prevention technique which has shown good technical potential is the two-stage flotation method developed for desulphurisation of hard rock tailings and coal fines, developed at the University of Cape Town. On desulphurising coal, the first stage produces an upgraded coal product that may be sold, with the second stage used to separate the tailings from the first stage into targeted high-sulphide and low-sulphide fractions which may then be appropriately used or disposed of. An economic assessment of the process showed across a wide range of coal wastes the high cost of oleic acid used in the first stage of the process as a collector was a major contributor to the operating costs. The investigation undertaken in this thesis looked at the potential of algal lipids and their derivatives as biocollectors to replace the oleic acid collector in the desulphurisation process at the laboratory scale. A review of cost was carried out for a process that used raw algal lipids (RALs) or fatty acid methyl esters (FAMEs), which are derived from RALs through transesterification. Batch flotation experiments were used to assess the performance of the two bioflotation reagents in comparison to oleic acid and dodecane, an alternative but less successful chemical collector. The algal lipids cost review was a desktop study which was done by adapting literature data from Davis et al. (2014) which focused on economic evaluation of algal lipid biofuels production pathways. Results from laboratory experiments for two different coal waste feed samples showed that the performance of RALs and FAMEs was similar to that of oleic acid for the sample that was high in ash and sulphur, and better than oleic acid for the sample that was low in ash and sulphur. For example, the product from Site 1 discards from Waterberg had 24.37% ash and 2.76% sulphur using FAMEs, 26.13% ash and 2.56% sulphur with RALs, and 23.48% ash and 2.41% using oleic acid, at a reagent dose of 2.8 kg/t for all reagents. For Site 2 waste tailings from the Witbank area, the product had 23.17% ash and 0.72% sulphur when FAMEs were used as collector, 22.75% ash and 0.75% sulphur with RALs, and 20.18% ash and 0.74% sulphur using oleic acid, at the same reagent dose. Discards from Site 1 had an initial ash and sulphur content of 47.61% and 5.71%, respectively. Site 2 waste tailings had 25.56% ash and 0.91% sulphur before flotation. Increasing biocollector dosage resulted in higher yields with a compromise on the upgraded coal quality. The pH tests showed that the performance of the two bioflotation reagents was best at pH 4 in terms of yield. However, increasing the pH of the process from the natural pH of the sample (pH 2.7) to 7 resulted in collection of more ash and sulphur, thus reducing the product quality. The algal lipids cost review showed that RALs and FAMEs were potentially 20 to 21% cheaper than oleic acid, with more room for improvement. Both the laboratory experiments and the technical evaluation showed that algal lipids and their derivatives have the potential to replace oleic acid in the two-stage desulphurisation process for coal waste to obtain a saleable quality coal product while simultaneously decreasing the impact of ARD from coal waste

Environmental life-cycle assessment of waste-coal pellets production

Industrial decarbonization is crucial to keeping the global mean temperature <1.5°C above pre-industrial levels. Although unabated coal use needs to be phased out, coal is still expected to remain an important source of energy in power and energy-intensive industries until the 2030s. Decades of coal exploration, mining and processing have resulted in ~30 billion tonnes of waste-coal tailings being stored in coal impoundments, posing environmental risks. This study presents an environmental life-cycle assessment of a coal-processing technology to produce coal pellets from the waste coal stored in impoundments. It has been shown that the waste-coal pellets would result in the cradle-to-gate global warming of 1.68–3.50 kgCO2,eq/GJch, depending on the source of electricity used to drive the process. In contrast, the corresponding figure for the supply of conventional coal in the US was estimated to be 12.76 kgCO2,eq/GJch. Such a reduction in the global-warming impact confirms that waste-coal pellets can be a viable source of energy that will reduce the environmental impact of the power and energy-intensive industries in the short term. A considered case study showed that complete substitution of conventional coal with the waste-coal pellets in a steelmaking plant would reduce the greenhouse-gas emissions from 2649.80 to 2439.50 kgCO2,eq/tsteel. This, in turn, would reduce the life-cycle greenhouse-gas emissions of wind-turbine manufacturing by ≤8.6%. Overall, this study reveals that the use of waste-coal pellets can bring a meaningful reduction in industrial greenhouse-gas emissions, even before these processes are fully decarbonized

Inherent safety health environment and economic assessment for sustainable chemical process design: Biodiesel case study

Chemical process design involves the development of chemical route that converts the feedstock to the desired product. During chemical process design, the sustainability features, i.e. safety, health and environmental (SHE), and economic performance (EP) should be established through assessment. However, at present, no relevant assessment framework with simultaneous consideration of SHE and EP is reported in literature. As improvement to the mentioned shortfall, this thesis presents four systematic frameworks for chemical process design based on multiple objectives of inherent SHE and EP. These frameworks are specifically dedicated for three design stages of (1) research and development, (2) preliminary engineering stage, and (3) basic engineering stage, and lastly (4) uncertainty analysis with the presence of multiple operational periods. Following the proposed frameworks, the mathematical optimisation models were developed for the assessment. Besides, multi-objective optimisation algorithm (fuzzy optimisation) and multi-period optimisation approach were also integrated into the frameworks to address the multiple objectives, uncertainties and multiple operational periods. To illustrate the frameworks proposed in this thesis, the assessments on biodiesel production pathway in different design stages were solved. Prior to the assessment, eight alternative biodiesel production pathways were identified based on literature. Through the evaluations and assessments in each design stage using the proposed frameworks, a final optimum biodiesel production pathway, i.e. enzymatic transesterification using waste vegetable oil, was designed through assessment. This pathway was further assessed and improved via assessment in basic engineering stage and uncertainty analysis. Following the assessments, several inherent SHE improvement strategies for all the three highlighted design stages were also suggested. Lastly, it can be concluded that the developed frameworks provide simplified yet effective ways for chemical process design based on the multi-objective of inherent SHE and EP