• Energy Research
• 6. Clean water close

The electromagnetic vibration caused by electromagnetic force on the stator has threatened large hydro generators operating safely and stably. At the Zhexi hydropower station, the hydro generator was beset by electromagnetic vibration for a long time. Therefore, the paper provided a new method to help to find the vibration source and detect the hydro generator fault, through the combination of simulation and experiments. In this paper, the 3D stator pack structure model and the 2D hydro generator electromagnetic models under rotor eccentricity and rotor ellipse deformation conditions were built. Then, electromagnetism simulations were conducted to study the characteristics of the electromagnetic flux and electromagnetic force under different conditions by using the finite element method (FEM). Lastly, the vibration testing experiments and harmonic response simulations of stator frame were performed to present the characteristics of vibration distribution in frequency conditions. The simulation results were compared with the generator measured data to try to find out the main vibration source and guide the overhaul.

This study was performed to investigate the effectiveness of submerged microfiltration to harvest both a marine diatom Phaeodactylum tricornutum and a Chlorella vulgaris in a recently developed magnetically induced membrane vibrating (MMV) system. We assess the filtration performance by conducting the improved flux step method (IFM), fed-batch concentration filtrations and membrane fouling autopsy using two lab-made membranes with different porosity. The full-scale energy consumption was also estimated. Overall results suggest that the MMV offers a good fouling control and the process was proven to be economically attractive. By combining the membrane filtration (15× concentration) with centrifugation to reach a final concentration of 25% w/v, the energy consumption to harvest P. tricornutum and C. vulgaris was, respectively, as low as 0.84 and 0.77kWh/m(3), corresponding to 1.46 and 1.39 kWh/kg of the harvested biomass.

Microalgae is considered as an excellent potential renewable source of fuel in many forms including powder or slurry. A high percentage of emulsified water in the fuel is reported to reduce diesel engines’ emissions such as NOx, but that will compromise the engine output power. Using microalgae powder as an additive to enhance the emulsified water fuel heating value is the main objective of this work. Diesel engine combustion, vibration, performance and emissions were evaluated for pure cottonseed biodiesel (CS-B100), emulsified water 20% (vol.) in cottonseed biodiesel (CSB-E20) and emulsified water 20% (vol.) containing Fresh Water Microalgae Chlorella Vulgaris (FWM-CV) in cottonseed biodiesel (CSB-ME20). The emulsified water fuels showed a reduction in in-cylinder pressure, vibration, brake power, torque, exhaust gas temperature, CO2 and NOx, while BSFC and O2 were higher than the pure biodiesel (CS-B100). CSB-ME20 produced higher power and torque than CSB-E20 due to the presence of microalgae in the fuel that increased the energy content of the fuel.

Dam and powerhouse operation sustainability is a major concern from the hydraulic engineering perspective. Powerhouse operation is one of the main sources of vibrations in the dam structure and hydropower plant; thus, the evaluation of turbine performance at different water pressures is important for determining the sustainability of the dam body. Draft tube turbines run under high pressure and suffer from connection problems, such as vibrations and pressure fluctuation. Reducing the pressure fluctuation and minimizing the principal stress caused by undesired components of water in the draft tube turbine are ongoing problems that must be resolved. Here, we conducted a comprehensive review of studies performed on dams, powerhouses, and turbine vibration, focusing on the vibration of two turbine units: Kaplan and Francis turbine units. The survey covered several aspects of dam types (e.g., rock and concrete dams), powerhouse analysis, turbine vibrations, and the relationship between dam and hydropower plant sustainability and operation. The current review covers the related research on the fluid mechanism in turbine units of hydropower plants, providing a perspective on better control of vibrations. Thus, the risks and failures can be better managed and reduced, which in turn will reduce hydropower plant operation costs and simultaneously increase the economical sustainability. Several research gaps were found, and the literature was assessed to provide more insightful details on the studies surveyed. Numerous future research directions are recommended.

{"references": ["Energy Information Administration of US Government, Available:\nhttp://www.eia.doe.gov/bookshelf/brochures/greenhouse/greenhouse.pdf\n.", "S. Bachu, J.J. Adams, \"Sequetration of CO2 in geological media in\nresponse to climate change: Capacity of deep saline aquifers to sequester\nCO2 in solution\", Energy Conversion and Management 44, 2003, pp.\n3151-3175.", "C. Song, \"Global challenges and strategies for control, conversion and\nutilization of CO2 for sustainable development involving energy, catalysis,\nadsorption and chemical processing\", Catalysis Today 115, (2006), pp.\n2-32.", "T.K. Flaathen, S.R. Gislason, E.H. Oelkers, A.E. Sveinbj\u00f6rnsd\u251c\u2502ttir:,\n\"Chemical evolution of the Mt. Hekla, Iceland, groundwaters: A natural\nanalogue for CO2 sequestration in basaltic rocks\", Applied Geochemistry,\n2009, 24, pp. 463-474.", "M. Kakizawa, A. Yamasaki, Y. Yanagisawa, \"A new CO2 disposal\nprocess via artificial weathering of calcium silicate accelerated by acetic\nacid\", Energy 26, (2001), pp. 341-354.", "World Consumption of Primary Energy by Energy Type and Selected\nCountry Groups, 1980-2006: Energy Information Administration, U.S.\nDepartment of Energy, available: http://www.eia.doe.gov/pub/\ninternational/iealf/table18.xls.", "J. K. Stolaroff, G. V. Lowry, D. W. Keith, \"Using CaO- and MgO-rich\nindustrial waste streams for carbon sequestration\", Energy Conversion\nand Management 46, 2005, pp. 687-699.", "S. Eloneva, S. Teir, J. Salminen, C.J. Fogelholm, R. Zevenhoven,\n\"Fixation of CO2 by carbonating calcium derived from blast furnace slag\",\nEnergy 33, 2008, pp. 1461-1467.", "D. Bonenfant, L. Kharoune., S. Sauve', R. Hausler, P. Niquette, M.\nMimeault, M. Kharoune, \"Molecular analysis of carbon dioxide\nadsorption processes on steel slag oxides\", International Journal of\nGreenhouse Gas Control 3, 2009, pp.20-28.\n[10] G.M. Hernandez, R.P. Lopez, F. Renard, J.M. Nieto, L. Charlet, \"Mineral\nsequestration of CO2 by aqueous carbonation of coal combustion fly-ash\",\nJournal of Hazardous Materials 161, 2009, pp. 1347-1354.\n[11] Iron and Steel Slag 2007 Report, Nippon Slag Association, Available:\nhttp://www.slg.jp/bib/download/fs-106.pdf.\n[12] S. Yokoyama, S. Sasaki, R. Sato, M.N.N. Hisyamudin, A. Susuki, M.\nUmemoto, \"Enhancement of reaction between CO2 and electric arc\nfurnace oxidizing slag by grinding\", Proceedings 4th International\nCongress on the Science and Technology of Steelmaking (ICS 2008),\nGifu Japan, 2008.\n[13] S. Yokoyama, R. Sato, M.N.N. Hisyamudin, M. Umemoto, \"Behavior of\nCO2 absorption in wet grinding of electronic arc furnace reducing slag\nfrom normal steelmaking process by vibration ball mill\", Tetsu-to-Hagane\n95, 2009, pp. 58-65.\n[14] M.N.N. Hisyamudin, S. Yokoyama, M. Kawakami, M. Umemoto,\n\"Reaction between CO2 and CaO under dry grinding\", (Accepted for\npublication), Powder Technology Elsevier, to be published."]} In this study, an experimental investigation was carried out to fix CO2 into the electronic arc furnace (EAF) reducing slag from stainless steelmaking process under wet grinding. The slag was ground by the vibrating ball mill with the CO2 and pure water. The reaction behavior was monitored with constant pressure method, and the change of CO2 volume in the experimental system with grinding time was measured. It was found that the CO2 absorption occurred as soon as the grinding started. The CO2 absorption under wet grinding was significantly larger than that under dry grinding. Generally, the amount of CO2 absorption increased as the amount of water, the amount of slag, the diameter of alumina ball and the initial pressure of CO2 increased. However, the initial absorption rate was scarcely influenced by the experimental conditions except for the initial CO2 pressure. According to this research, the CO2 reacted with the CaO inside the slag to form CaCO3.

{"references": ["Energy Information Administration of US Government, Available: http://www.eia.doe.gov/bookshelf/brochures/greenhouse/greenhouse.pdf.", "S. Bachu, J.J. Adams, Sequetration of CO2 in geological media in response to climate change: Capacity of deep saline aquifers to sequester CO2 in solution, Energy Conversion and Management 44, 2003, pp. 3151-3175.", "C. Song, Global challenges and strategies for control, conversion and utilization of CO2 for sustainable development involving energy, catalysis, adsorption and chemical processing, Catalysis Today 115, (2006), pp. 2-32.", "T.K. Flaathen, S.R. Gislason, E.H. Oelkers, A.E. Sveinbjrnsdttir:, Chemical evolution of the Mt. Hekla, Iceland, groundwaters: A natural analogue for CO2 sequestration in basaltic rocks, Applied Geochemistry, 2009, 24, pp. 463474.", "M. Kakizawa, A. Yamasaki, Y. Yanagisawa, A new CO2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid, Energy 26, (2001), pp. 341354.", "World Consumption of Primary Energy by Energy Type and Selected Country Groups, 1980-2006: Energy Information Administration, U.S. Department of Energy, Available: http://www.eia.doe.gov/pub/ international/iealf/table18.xls.", "J. K. Stolaroff, G. V. Lowry, D. W. Keith, Using CaO- and MgO-rich industrial waste streams for carbon sequestration, Energy Conversion and Management 46, 2005, pp. 687-699. Ca2SiO4MgSiO3KAlSi3O8", "S. Eloneva, S. Teir, J. Salminen, C.J. Fogelholm, R. Zevenhoven, Fixation of CO2 by carbonating calcium derived from blast furnace slag, Energy 33, 2008, pp. 1461-1467.", "D. Bonenfant, L. Kharoune., S. Sauve, R. Hausler,P. Niquette, M. Mimeault, M. Kharoune, Molecular analysis of carbon dioxide adsorption processes on steel slag oxides, International Journal of Greenhouse Gas Control 3, 2009, pp.20-28. [10] G.M. Hernandez, R.P. Lopez, F. Renard, J.M. Nieto, L. Charlet, Mineral sequestration of CO2 by aqueous carbonation of coal combustion fly-ash, Journal of Hazardous Materials 161, 2009, pp. 1347-1354. [11] Iron and Steel Slag 2007 Report, Nippon Slag Association, Available: http://www.slg.jp/bib/download/fs-106.pdf.[12] S. Yokoyama, M.N.N. Hisyamudin, Y. Nagao and M. Kawakami, Adsorption reaction of CO2 to CaO and waste cement under dry grinding, Extended Abstracts of International Symposium on Eco Topia Science 2005, Nagoya Japan, 2005, pp.718-711. [13] S. Yokoyama, S. Sasaki, R. Sato, M.N.N. Hisyamudin, A. Susuki, M. Umemoto, Enhancement of reaction between CO2 and electric arc furnace oxidizing slag by grinding, Proceedings 4th International Congress on the Science and Technology of Steelmaking (ICS 2008), Gifu Japan, 2008. [14] B.M.N Nik Hisyamudin, S. Yokoyama, M. Kawakami, M. Umemoto, Reaction between CO2 and CaO under dry grinding, submitted for publication."]} In the current study, we have conducted an experimental investigation on the utilization of electronic arc furnace (EAF) reducing slag for the absorption of CO2 via wet grinding method. It was carried out by various grinding conditions. The slag was ground in the vibrating ball mill in the presence of CO2 and pure water under ambient temperature. The reaction behavior was monitored with constant pressure method, and the changes of experimental systems volume as a function of grinding time were measured. It was found that the CO2 absorption occurred as soon as the grinding started. The CO2 absorption was significantly increased in the case of wet grinding compare to the dry grinding. Generally, the amount of CO2 absorption increased as the amount of water, weight of slag and initial pressure increased. However, it was decreased when the amount of water exceeds 200ml and when smaller balls were used. The absorption of CO2 occurred simultaneously with the start of the grinding and it stopped when the grinding was stopped. According to this research, the CO2 reacted with the CaO inside the slag, forming CaCO3.

The process and equipment have been developed for preparation and burning (at small and medium capacity boiler plants) of slurry coal-water fuel, produced from finely dispersed coal preparation waste (filter cakes) from coal preparation plants of Komsomolets Mine and Named after S. M. Kirov Mine. It was shown that, based on these wastes, it is possible to produce slurry coal-water fuel with solids content of 56-60 %, the required structural and rheological characteristics, and lower heating value of up to 13 MJ/kg. Based on the research findings, detail design was developed for creation of the pilot process complex for processing of waste coal to produce slurry coal-water fuel for burning at boiler plant. Assessment of using the whole volume of the SUEK Kuzbass coal preparation plants waste coal at the nearby Belovskaya SDPP was performed, which showed high economic and environmental efficiency of the proposed project.

This paper presents a study of the properties of soil–rock mixtures (SRM) prepared by the vibration compaction method. First, the results of laboratory experiments and field tests are compared to determine the reasonable parameters of the vibration compaction method (VCM) for soil–rock mixtures. The compaction characteristics, CBR, and resilient modulus of the laboratory-prepared soil–rock mixtures by the static pressure compaction method (SPCM) and vibration compaction method are compared. The effects of the soil to rock ratio and the maximum particle size and gradation on the compaction characteristic, resilient modulus and CBR of soil–rock mixtures prepared by the vibration compaction method are investigated. Finally, field measurements are subsequently conducted to validate the laboratory investigations. The results show that the reasonable vibration frequency, exciting force, and static surface pressure of the vibration compactor for soil–rock mixtures are recommended as 25 Hz, 5.3 kN, and 154.0~163.2 kPa, respectively. Soil–rock mixtures prepared by vibration compaction method has smaller optimum water content and gradation variation and larger density than specimens prepared by the static pressure compaction method, and the CBR and resilient modulus are 1.46 ± 0.02 and 1.16 ± 0.03 times those of specimens prepared by the static pressure compaction method, respectively. The ratio of soil to rock, followed by the maximum particle size, lead obvious influences on the properties of soil–rock mixtures. Moreover, the results show that the CBR and resilient modulus of soil–rock mixtures prepared by vibration compaction method have a correlation of 86.9% and 89.1% with the field tests, respectively, which is higher than the static pressure compaction method.