The cyclonic dryer: a numerical and experimental analysis of the influence of geometry on average particle residence time

Particle residence time is an extremely important variable in a cyclonic dryer project. With the goal of obtaining a device that conduces to a long particle residence time, the influence of cyclone dimensions on particle residence time and on the type of flow is discussed here. The research was based on a device with a very high ratio of cyclone diameter to other dimensions. Simulations were developed with computational fluid dynamics techniques by the use of the commercial code CFX 4.4® of AEA Technology. Particles were treated individually. The fit of a turbulence model was also discussed. Theoretical and experimental results showed that the dimensions of the conical part of the cyclone had a very important influence on flow and consequently on particle residence time. The influences of volumetric concentration and particle diameter on particle residence time were also observed.103112Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Working sick and out of sorts: a cross-cultural approach on presenteeism climate, organizational justice and work-family conflict

A climate of presenteeism has important effects on employee well-being and the organization itself. Our study, based on surveys of health sector employees in six different countries (Brazil, Ecuador, Lebanon, Portugal, Russia and Spain) examines whether organizational justice plays a mediating role in the relationship between a presenteeism climate in the organization and work-family conflict (WFC). Our results indicate that the perception of organizational justice and the presenteeism climate do influence WFC. Moreover, higher levels of WFC were found in non-Latin countries. This study contributes to the work attendance and life balance field by providing cross-cultural empirical evidence corroborating the effect of justice and presenteeism climate on the WFC

Ethanol Production By Enzymatic Hydrolysis From Sugarcane Biomass-the Integration With The Conventional Process

The aim of this study is to make an evaluation of the possibilities of ethanol production increase through the introduction of bagasse hydrolysis process in conventional distilleries, considering the limiting situation of bagasse use: it is the major by-product in sugar and ethanol production and is burnt in boilers to satisfy the steam and power requirements of the process. Simulations in ASPEN PLUS® software were performed, in order to evaluate the mass and energy balances, for the integrated process, considering the pre-treatment of sugarcane bagasse by steam explosion. The cogeneration system was also modelled and integrated with the ethanol production process. It consists of a steam cycle with backpressure steam turbines and parameters of live steam of 67 bar and 480°C. In all the cases studied it was considered that the steam flowused in the system was just that necessary to fulfil the process thermal needs, so, it was assumed that the surplus of bagasse was used to produce ethanol. The use of sugarcane trash was considered in order to accomplish the energetic needs of the overall process as well as lignin cake, which is a hydrolysis process residue. Several cases were evaluated, which include: the conventional ethanol production plant without hydrolysis (Case I), the conventional plant joint with hydrolysis process without thermal integration considering different solid contents in the hydrolysis reactor (Cases II, III and IV), and the conventional plant joint with the hydrolysis process considering thermal integration through Pinch method (Case V). The results shown a modest ethanol production increase of 9.7% for the situation without thermal integration and low solid content in the hydrolysis reactor, on the other hand, the case where thermal integration was applied presented an ethanol production increase of 17.4%.5159172Leite, R.C.C., Fuel bioethanol an opportunity to Brazil (2009), Brasilia: Centro de Gestão e Estudos Estratégicos, In PortugueseRein, P., Cane Sugar Engineering (2007), Berlin: Verlag Dr. Albert Bartens K. GWooley, R.J., Putsche, V., Development of an ASPEN PLUS Physical Property Database for Biofuels Components (1996), www.p2pays.org/ref/22/21210.pdf, National Renewable Energy Laboratory, Available at, accessed 12.11. 2007Palacios-Bereche, R., Modeling and energy integration of the ethanol production process from sugarcane biomass [PhD Thesis] (2011), Campinas, Brazil: University of Campinas, In PortugueseDias, M.O.S., Simulation of ethanol production processes from sugar and sugarcane bagasse, aiming process integration and maximization of energy and bagasse surplus (2008), [dissertation]. Campinas, Brazil: University of Campinas, In PortugueseEijsberg, R., The design and economic analysis of a modern bioethanol factory located in Brazil (2006), [dissertation]. Delft, The Netherlands: University DelftRossell, C.E.V., Sugarcane processing to ethanol for fuel purposes (1988) Chemistry and Processing of Sugarbeet and Sugarcane, , In, edited by Clarke M. A. and Godshall M.A., Elsevier Science Publishers B. V., AmsterdamFinguerut, Fermentation, Hydrolysis and Distillation (2008) Biomass for Energy, pp. 436-474. , In: Cortes et al. editors, Campinas, Brazil: Ed. UnicampDias, M.O.S., Modesto, M., Ensinas, A.V., Nebra, S.A., Maciel Filho, R., Rossell, C.E.V., Improving bioethanol production from sugarcane: evaluation of distillation, thermal integration and cogeneration systems (2010) Energy, 36, pp. 3691-3703Palacios-Bereche, R., Nebra, S.A., Thermodynamic modeling of a cogeneration system for a sugarcane mill using ASPEN PLUS, difficulties and challenges (2009), COBEM 2009: Proceedings of the 20th International Congress of Mechanical Engineering, Nov 15-20, Gramado, BrazilMagnusson, H., Process simulation in Aspen Plus of an integrated ethanol and CHP plant (2005), [dissertation]. Sweden: Umea UniversitySun, Y., Cheng, J., Hydrolysis of lignocellulosic materials for ethanol production: a review (2002) Bioresource Technology, 83, pp. 1-11Efe, C., Technical and economical feasibility of production of ethanol from sugar cane and sugarcane bagasse (2005), [dissertation], Delft, The Netherlands: TU-DelftCarrasco, C., Baudel, H.M., Sendelius, J., Modig, T., Roslander, C., Galbe, M., Hahn-Hägerdal, B., Lidén, G., SO2-catalyzed steam pretreatment and fermentation of enzymatically hydrolyzed sugarcane bagasse (2010) Enzyme and Microbial Technology, 46, pp. 64-73Kling, S.H., Carvalho Neto, C., Ferrara, M.A., Torres, J.C.R., Magalhaes, D.B., Ryu, D.D.Y., Enhancements of enzymatic hydrolysis of sugar cane bagasse by steam explosion pretreatment (1987) Biotechnology and Bioengineering, 29, pp. 1035-1039Sanchez, O.J., Cardona, C.A., Trends in biotechnological production of fuel ethanol from different feedstocks (2008) Bioresource Technology, 99, pp. 5270-5295Jorge, L.M.M., Righetto, A.R., Polli, P.A., Santos, O.A.A., Maciel Filho, R., Simulation and analysis of a sugarcane juice evaporation system (2010) Journal of Food Engineering, 99, pp. 351-359Cardona, C.A., Sanchez, O.J., Energy consumption analysis of integrated flowsheets for production of fuel ethanol from lignocellulosic biomass (2006) Energy, 31 (13), pp. 2447-2559Walter, A., Ensinas, A.V., Combined production of second-generation biofuels and electricity from sugar-cane residues (2010) Energy, 35, pp. 874-879Hassuani, S.J., Leal, M.R.L.V., Macedo, I.C., Biomass power generation: Sugarcane bagasse and trash, Piracicaba (2005), Brazil: Ed. PNUD and CTCMichelazzo, M.B., Sensitivity analysis of six systems for collection of sugarcane trash (Saccharum spp.) (2005), [dissertation]. Campinas, Brazil: University of Campinas, In PortugueseWestphalen, D.L., Wolf Maciel, M.R., Pinch Analysis of evaporation systems (2000) Brazilian Journal of Chemical Engineering, 17, pp. 4-7Pereira, L.T.C., Teixeira, R.S.S.T., Bom, E.P.S., Freitas, S.P., Sugarcane bagasse enzymatic hydrolysis: rheological data as criteria for impeller selection (2010) Journal of Industrial Microbiology & Biotechnology, , DOI 10.1007/s10295-010-0857-8Dias, M.O.S., Ensinas, A.V., Nebra, S.A., Maciel Filho, R., Rossell, C.E.V., Production of bioethanol and other bio-based materials from sugarcane bagasse: Integration to conventiona l bioethanol production process (2009) Chemical Engineering Research and Design, 87, pp. 1206-1216Galbe, M., Zacchi, G., Ethanol production from lignocellulosic materials (2010) Bioethanol from sugarcane: R&D for productivity and sustainability, 12, pp. 697-716. , In: CORTEZ, L.A.B. (Coord.), Sao Paulo: Blucher, Part. 4, ChapCella, N., Trash use as fuel in biomass boilers. Course Boilers, Environment and Renewable Energy (2010) Ribeirao Preto, , 23-24 de juneDias, M.O.S., Cunha, M.P., Maciel Filho, R., Bonomi, A., Jesus, C.D.F., Rossell, C.E.V., Simulation of integrated first and second generation bioethanol production from sugarcane :comparison between different biomass pre-treatment methods (2011) Journal of Industrial Microbiology & Biotechnology, 38, pp. 955-96

Synthesis and parameter optimization of a combined sugar and ethanol production process integrated with a CHP system

The combined sugar and ethanol production process from sugar cane is a paradigmatic application for energy integration strategies because of the high number of hot and cold streams involved, the external hot utility requirement at two temperature levels for juice evaporation and crystallization, and the electricity demand for juice extraction by milling. These conditions make it convenient to combine the sugar-cane process with a CHP system fuelled by bagasse, the main by-product from juice extraction. The strategies, tools and expertise on energy integration developed separately by the research teams authoring this paper are applied here jointly to optimize the synthesis and the design parameters of the process and of the total site starting from the basic idea of dissociating the heat exchanger network design problem from the total site synthesis problem. At first the minimization of the external heat requirement for the process alone is pursued and results show that a one third reduction can be achieved by optimal heat integration. Then the use of the by-product bagasse for on-site power generation is considered and two bagasse-fuelled CHP systems are optimized along with some parts of the sugar and ethanol production process in order to obtain maximum total site net power. Results show a variety of interesting scenarios of combined sugar, ethanol and electricity production plants with considerably high electricity output

Study of the economic viability of cogeneration systems in Portugal: the impact of legislation on the investment decision

In Portugal, several decades ago, both academic and industry experts gathered to investigate opportunities for increasing the efficiency of power plants and promoting the cogeneration systems. In Portugal, until 1990, the market penetration rate for cogeneration was reduced, being the total installed capacity below 530 electrical MW. Nevertheless, the government implemented policies to promote the self-production of electricity with the possibility of selling the surplus energy under special remuneration schemes (e.g. feed-in-tariffs). However, the publication of a legal framework providing lower electricity tariffs and reducing the bonuses from the system's operation, over the last few years, has contributed to a considerable setback to the cogeneration activity. Consequently, the new investments decreased and several power plants will be shut down as soon as they finished their period of permanence in the previous legal framework. In this paper, a calculus methodology to analyse the feasibility and economic viability of cogeneration systems is implemented taking into account the sale of the total electricity production under the Decree-Law n.degrees 23/2010 and Decree-Law n.degrees 68-A/2015. The methodology was applied to a realistic scenario of an industrial cogeneration plant with a power capacity of 4MW running on natural gas. All the thermal energy is used in the production of steam and hot water for industrial processes. Knowing the amount of produced energy and the reference tariff, it is possible to calculate the remuneration corresponding to the energy supplied to the national electricity grid. The total remuneration of electricity is then calculated considering the application of high-efficiency bonuses. The methodology includes the efficiency harmonized reference values for a specific technology. Regarding the thermal energy, the equivalent cost of its production might be assumed constant, regardless of the remuneration regime in which the cogeneration is included. The total value of the cogenerationThe first the author is grateful for the support given by the Portuguese Foundation for Science & Technology (FCT) through the Post-Doc Grant SFRH/BPD/121446/2016. This work has been supported by FCT within the Project Scope UID/CEC/00319/2019 (ALGORITMI) and Project Scope UID/EMS/04077/2019 (METRICS). Also, the authors are thankful for the data provided by the company CapWhatt to support this study

Design of a solar dish Stirling cogeneration system: Application of a multi-objective optimization approach

Energy market consumption is expected to increase by 44% from 2006 to 2030, mostly because of the lifestyle standards evolution, and development of industries and economics. In addition, the variations of the fossil fuel prices and the increase in pollutant gas emissions have instigated the research on other types of power generation systems. From the available technologies, Stirling systems have demonstrated simplicity and reliability, which are the key parameters to develop a cost-effective energy system. The study aims the development of a methodology for the thermal-economic optimization, at the design stage, of micro-CHP systems based on Stirling engine technology, and combined with a renewable energy source, the solar energy. To properly size the system, a methodology is proposed to define the total annual thermal power duration curve of a reference residential building in the North of Portugal. The methodology accounts for both heating and the domestic hot water needs. The thermal-economic model was formulated as an non-linear optimization problem with non-linear constrains. Each component of the cycle is modelled using the energy balances of the first law of thermodynamics. It is also proposed an economic model that defines the purchase cost of each system component. The cost equations include thermodynamic variables that directly affect the component cost and performance. The model yields two non-linear objective functions: the minimization of the total investment cost and the maximization of the efficiency of the system. Numerical simulations were developed in MatLab programming language using evolutionary algorithms. The multi-objective optimization results were expressed by Pareto curves. The obtained curve disclosed several design possibilities for which the thermal efficiencies vary between 66.3% and 76.1% for an annualized investment costs fluctuating between 1250 €/year and 2675 €/year.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and Portuguese Foundation for Science and Technology (FCT) within the Project Scope: UID/CEC/00319/2013. This work was also financed by National Funds of FCT under Strategic Project UID/SEM/04077/2013.info:eu-repo/semantics/publishedVersio