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Performance and exhaust emissions of an indirect-injection (IDI) diesel enginewhen using waste cooking oil as fuel
Aleš Hribernik, Breda Kegl, 2009, izvirni znanstveni članek

Opis: A study was carried out on the influence of waste cooking oil (WCO) and its blends with D2 fuel on the performance, exhaust emissions, combustion and fuel injection processes of an indirect injected diesel engine. Tests were carried out using different fuels, under the same conditions. Exhaust emissions and engine performance were measured and compared. Combustion chamber pressure was also acquired, and the rate of heat-release curves were computed by means of a zero-dimensional one-zone combustion model. Some macro-parameters of the combustion process were obtained from the heat-release-rate curves. The injection system was separated from the engine and tested on a special test bench. The injected fuel quantity was measured, and the injection pressure and injector needle lift time history were acquired. The injection-rate curves were then computed, and some macro-parameters of the injection process were obtained and analyzed.
Ključne besede: diesel engine, waste cooking oil, exhaust emissions
Objavljeno: 31.05.2012; Ogledov: 766; Prenosov: 17
URL Celotno besedilo (0,00 KB)

3.
Numerical optimisation of a waste-to-energy plant's operating parameters using CFD
Miran Kapitler, Niko Samec, Filip Kokalj, 2011, izvirni znanstveni članek

Opis: The combustion process for using municipal solid waste as a fuel within a waste to energy plant calls for a detailed understanding of the following phenomena. Firstly, this process depends on many input parameters such as proximate and ultimate analyses, the season of the year, primary and secondary inlet air velocities and, secondly, on output parameters such as the temperatures or mass-flow rates of the combustible products. The variability and mutual dependence of these parameters can be difficult to manage in practice. Another problem is how these parameters can be tuned to achieving optimal combustible conditions with minimal pollutant emissions, during the plant-design phase. in order to meet these goals, a waste-to-energy plant with bed combustion was investigated by using computational fluid-dynamics approach. The adequate variable input boundary conditions based on the real measurement are used and the whole computational work is updated using real plant geometry and the appropriate turbulence, combustion, or heat transfer models. The operating parameters were optimized on output parameters through a trade-off study. The different operating conditions were varied and the combustible products were predicted and visualized. Finally, the response charts and matrix among the input and output parameters during the optimization process are presented, which monitored the dependence among these parameters.
Ključne besede: municipal solid waste, bed combustion, computational fluid dynamics, numerical optimization, goal driven optimization, trade-off study, parameters correlation
Objavljeno: 01.06.2012; Ogledov: 887; Prenosov: 38
.pdf Celotno besedilo (1,83 MB)

4.
Combustion simulation in the secondary chamber of a pilot-scale incinerator
Niko Samec, Filip Kokalj, Jyh-Yan Chen, 2007, izvirni znanstveni članek

Opis: A numerical analysis of combustion in the secondary chamber (thermoreactor) ofa two-stage pilot scale incinerator using computational fluid dynamics (CFD)is presented in detail. Various versions of the CFD program package CFX were used, which offer different combustion models for specific types and forms of combustion processes. The present study was focused on those physicalconditions that assure complete combustion, that is, temperature, residence time, and turbulent mixing. The selection of an appropriate combustion model was based on a comparison of the numerical results and experimental values of some combustion macro parameters in a thermoreactor. Combustion models based on one-step bimolecular chemical reaction and models based on multistep reactions were used. These models enabled a more detailed prediction of the combustion process in the secondary chamber of a pilot-scaleincinerator. The products of incomplete combustion that are significantly important for the designing and optimization of combustion devices can be predicted by applying multistep reaction models more accurately, especially in a transient regime of combustion.
Ključne besede: waste incineration, numerical modeling, combustion models, incinerator chamber, CFX, CFD, computational fluid dynamics
Objavljeno: 31.05.2012; Ogledov: 1125; Prenosov: 20
URL Celotno besedilo (0,00 KB)

5.
Comparison of the performances of absorption refrigeration cycles
Zvonimir Črepinšek, Darko Goričanec, Jurij Krope, 2009, izvirni znanstveni članek

Opis: This paper compares the performance of absorption refrigeration cycles that are used for refrigeration temperatures below 0°C. Since the most common vapor absorption refrigeration systems use ammonia-water solution with ammonia as the refrigerant and water as the absorbent, research has been devoted to improvement of the performance of ammonia-water absorption refrigeration systems in recent years. In this paper the performances of the ammonia-water and possible alternative cycles as ammonia-lithium nitrate, ammonia-sodium thiocyanate, monomethylamine-water, R22-DMEU, R32-DMEU, R124-DMEU, R152a-DMEU,R125-DMEU, R134a-DMEU, trifluoroethanol (TFE)-tetraethylenglycol dimethylether (TEGDME), methanol-TEGDME and R134a-DMAC are compared in respect of the coefficient of performance (COP) and circulation ratio (f). The highest COP and the lowest f, were found as a function of the generator, condenser, absorber and evaporating temperature.
Ključne besede: absorption, refrigeration, working fluids, COP, circulation ratio, waste heat
Objavljeno: 31.05.2012; Ogledov: 1286; Prenosov: 17
URL Celotno besedilo (0,00 KB)

6.
FP7 EU project AquaFit4Use - synergy of 4 industrial sectors with the goal of waste water recycling
Alenka Majcen Le Marechal, Simona Vajnhandl, Darko Golob, 2009, strokovni članek

Opis: Sustainable water use in industry is the goal of AquaFit4Use, by a cross-sectorial, integrated approach. The overall objectives are: the development and implementation of new, reliable, cost-effective technologies, tools and methods for sustainable water supply, use and discharge in the main water consuming industries in order to significantly reduce water use, mitigate environmental impact and produce and apply water qualities in accordance with industrial own specifications (fit - for - use) from all possible sources, and contributing to a far-going closure of the water cycle in a economical, sustainable and safe way while improving their product quality and process stability.
Ključne besede: waste water recycling, reduce water use, water quality, sustainable water supply
Objavljeno: 31.05.2012; Ogledov: 1532; Prenosov: 11
URL Celotno besedilo (0,00 KB)

7.
Application of cyclodextrins in textile dyeing
Bojana Vončina, 2011, samostojni znanstveni sestavek ali poglavje v monografski publikaciji

Ključne besede: textile dyeing, cyclodextrins, dyeing auxiliaries, polyfunctionalization, textile waste water
Objavljeno: 01.06.2012; Ogledov: 734; Prenosov: 19
URL Celotno besedilo (0,00 KB)

8.
Laundry wastewater treatment using coagulation and membrane filtration
Sonja Šostar-Turk, Irena Petrinić, Marjana Simonič, 2005, izvirni znanstveni članek

Opis: This paper presents the results obtained from laundry wastewater treatment using conventional methods namely precipitation/coagulation and the flocculation process with adsorption on granular-activated carbon (GAC) and an alternative method, membrane filtrations, namely ultrafiltration (UF) and reverse osmosis (RO). Chemical analyses showed that parameter values of untreated wastewater like temperature, pH, sediment substances, total nitrogen and phosphorous, COD, BOD5, and the amount of anion surfactants had been exceeded in regard to Slovenian regulation. These regulations can be used as requirements for wastewater reuse and make treated wastewater an available source for the existing water supply. The study of conventional treatment was based on a flocculation with Al2(SO4)3 18H2O and adsorption on GAC. Membrane filtrations were studied on a pilot wastewater treatment plant: ultrafiltration (UF) and reverse osmosis (RO) units. The membranes used in this experiment were ceramic UF membrane and spiral wounded - polyethersulfone- RO membranes. The quality of the wastewater was improved by both methods and the specifications of a concentration limit for emission into water were confirmed. The disadvantage of GAC is that there is no possibility of any kind of selection, which is essential for recycling and re-use, while permeate coming from RO met the required regulation as well as requirements for reusing in washing process. However, the economical analyses showed that the membrane filtrations are more expensive compared to the GAC treatment process.
Ključne besede: laundries, washing of textiles, waste waters, advanced oxidation processes, membrane technology, membrane filtration, coagulation
Objavljeno: 01.06.2012; Ogledov: 1294; Prenosov: 29
URL Celotno besedilo (0,00 KB)

9.
Utilization of bottom ash from the incineration of separated wastes as a cement substitute
Filip Kokalj, Niko Samec, Bernardka Jurič, 2005, izvirni znanstveni članek

Opis: Waste incineration is still an essential technology in the concept of integrated waste management. Most of the combustion residues are incinerator bottom ash. It has been discovered that incinerator bottom ash from the incineration of separated waste in the primary chamber of the modular two-stage incinerator mainly consists of metal oxides, especially SiO2 and CaO, in proportions that are quite similar to those in cement and so the feasibility of its application as a substitute for cement in concrete was investigated. It was found that after 28 days, the flexural and compressive strengths of the binder using bottom ash were practically comparable with those of a pure cement mixture. The results show that it is reasonable to use a binder containing incinerator bottom ash for applications in which an early-stage lower strength of concrete element is acceptable.
Ključne besede: waste management, solid municipal waste, separated wastes incineration, bottom ash, cement, concrete
Objavljeno: 01.06.2012; Ogledov: 1043; Prenosov: 19
URL Celotno besedilo (0,00 KB)

10.
Improving the economic and environmental performances of the beet sugar industry in Slovenia: increasing fuel efficiency and using by-products for ethanol
Damjan Krajnc, Miro Mele, Peter Glavič, 2007, izvirni znanstveni članek

Opis: This paper investigates the possibilities of attaining zero-waste emissions inthe case of sugar production. The case-studied sugar plant located in Slovenia reflected a typical plant, using traditional sugar production from beet. An investigation of the possible use of waste and by-products from sugarprocessing was carried out, in order to approach zero-waste from beet sugar processing. The sugar production process was simulated and optimization was carried out concerning energy utilization. Consumption of energy in the chosen sugar plant was lowered by simultaneous optimization of the evaporationand crystallization process. Changing the fuel type used in the case-studied sugar plant (replacement of heavy fuel oil with natural gas) produced a significant decrease in air emission. Opportunities in the sugar industry have been discovered for adapting to new market conditions through the optimization of combined sugar-ethanol production. The two proposed options have been economically and environmentally evaluated and compared.
Ključne besede: kemična industrija, trajnostni razvoj, proizvodnja sladkorja, minimiranje porabe energije, evaporacija, etanol, chemical industries, sustainable development, sugar production, energy minimization, evaporation, ethanol, zero waste
Objavljeno: 01.06.2012; Ogledov: 1501; Prenosov: 12
URL Celotno besedilo (0,00 KB)

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