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COB65 DESIGN AND DEVELOPMENT OF A CONTINUOUS CORK STOPPERS DRYER

C.M.C.T. Pinho & A.M.S. Santos

Departamento de Engenharia Mecânica e Gestão Industrial. F.E.U.P.

Rua dos Bragas, 4099 PORTO CODEX, Portugal - E-mail: ctp@fe.up.pt

Abstract

The drying of cork stoppers is a technological process commonly used in the stoppers manufacturing industry. Until recently no systematic scientific approach had been undertaken in the study of the drying kinetics of cork stoppers. An historical account of the sequence of steps followed in the design and erection of a new continuous dryer comissioned to the university is presented. The short time period required for the implementation of the new dryer lead to a twin path approach of the problem. A fundamental study of the kinetics of the drying process of slim fixed beds of cork stoppers was simultaneously accompanied by a study of the drying of batches of stoppers, as received from the industrial washery process. Data from this preliminary analysis were used in the design of the new dryer whereas data from the fundamental study were used in the final adjustment of dryer working conditions. Analysis of the behaviour of the dryer in the industrial environment showed a satisfactory performance and although the actual energy consumption is two and half times larger than the latent heat of water vaporization, experimental results are of the same order of magnitude of those found in the wood drying processes, which were used as references due to the lack of experimental data on industrial drying of cork.

Keywords

Cork stoppers drying. Industrial dryers.

COB317 Análise Termoeconômica da Cogeração de Eletricidade a partir do Bagaço de Cana EM UMA USINA DE SÃO PAULO/THERMOECONOMIC ANALYSIS OF ELECTRICITY COGENERATION FROM SUGARCANE BAGASSE IN A SÃO pAULO PLANT.

Suani Teixeira Coelho

Instituto de Eletrotécnica e Energia da Universidade de São Paulo (IEE/USP)

Av. Prof. Almeida Prado, 925 - 05674-010 - São Paulo, Brasil - E-mail: suani@iee.usp.br

Silvio de Oliveira Junior

Instituto de Pesquisas Tecnológicas de São Paulo (IPT)-Escola Politécnica da USP

C.P. 7141, 01064-970 - São Paulo - Brasil - E-mail: olivsilj@dce03.ipt.br

David Zylbersztajn

Secretaria de Energia do Estado de São Paulo - IEE/USP

Rua Bela Cintra, 847 - 01415-000 - São Paulo - Brasil

Despite the advantages of cogeneration process for sugar/alcohol plants, as well as for electric sector and the whole Brazilian society, the protocol signed between the Government of São Paulo State and this industrial segment has not yet achieved its stated objectives. Besides other difficulties, one of the main problems is the sale’s price of electricity. This paper intends to contribute to such discussion, by adapting thermoeconomic analysis to cogeneration process in a sugar/alcohol plant of São Paulo. Exergy-based costs of process steam and electricity are evaluated for different configurations, from existing estimates of surplus electricity and corresponding investments. "Equality", "extraction" and "electricity-as-by-product" methods are utilized, the adopted configurations corresponding basically to Rankine steam cycle (currently commercialized in Brazil). Generation costs are calculated and compared to current electricity purchase’s price proposed by the utilities, leading to the discussion of mechanisms to improve a large scale cogeneration program in São Paulo State.

Keywords: Cogeração; bagaço de cana; exergia; análise termoeconômica/Cogeneration; sugarcane bagasse; exergy; thermoeconomic analysis.

COB330 CARBONATO-APATITA: ANÁLISE TERMODINÂMICA DA SUA FORMAÇÃO E COMPORTAMENTO DURANTE O SEU AQUECIMENTO

Tsuneharu Ogasawara¹, Mizue Ogasawara²

¹ COPPE/UFRJ PEMM, Caixa Postal 68505 - Ilha do Fundão, 21945-970 - Rio de Janeiro/RJ, (021)2807443, ogasawat@metalmat.ufrj.br

² UFSCar/Centro de Ciências Biológicas e da Saúde/Depto. de Enfermagem, Caixa Postal 676, 13565-905 - São Carlos/SP, (016)2712081

The paper intended to give the science and technology of hydroxyapatite production and usage the suitable equilibrium diagrams capable to show clearly the conditions under which carbonateapatite can result as a transformation product of the former apatite; that knowledge is highly valuable to understand the behavior of the hydroxyapatite coating metallic implant biomaterials in human fluid body solution. Therefore, free energy of the carbonateapatite at 25'C was estimated from similarity between the formation reaction of the hydroxyapatite from beta-tricalcium phosphate and calcium hydroxide and of the carbonateapatite from beta-tricalcium phosphate and calcium carbonate. The molar entropy and heat capacity at constants pressure of the carbonateapatite were determined through estimation conventional methods everywhere available. Then, potential-pH diagrams of the Ca-C-P-H20 system at 25 and IOOOC have been calculated and drawn using the Computing Software Chemistry for Windows 2.0 from Outokumpu Oy, Finland, as licensed to the COPPE/UFRJ. In the following, activity-pH diagrams have been drawn at these two temperatures and analyzed. The conditions of the stability of the carbonateapatite have been well set up.

Keywords: carbonateapatite, hydroxyapatite, bone and dental implant material, hydroxyapatite coating on metal implants,

then-nodynamic analysis

COB502 ANÁLISE TÉCNICA E ECONÔMICA DE SISTEMAS DE COGERAÇÃO PARA UM LATICÍNIO DE PEQUENO PORTE / A TECHNICAL AND ECONOMICAL ANALYSIS OF A COGENERATION SYSTEM FOR A SMALL LATICINIO PLANT

Antonio Pantalena, José Luz Silveira & Luiz Roberto Carrocci

Departamento de Energia, Faculdade de Engenharia Mecânica - UNESP - Guaratinguetá

CEP 12500-000 Guaratinguetá, Brasil - E-mail: joseluz@feg.unesp.br & carrocci@feg.unesp.br

In all part of the world, the necessary improvement of energy conservation and the search of new energy generation technologies became priority at the science, in the engineering and for the government; usually having preoccupation with the future’s environment. Then, the rational utilization of the energy ware exited cogeneration’s technologies. In the last years are getting a great interesting by cogeneration system because the increase of the fuels cost, the hardness to get more efficiency at conventional thermoeletrics, the possibility of reduction of the energy costs like the increase of gain and competitively of your products in world market. This article can make an technical and economic analyzes of use of cogeneration’s systems of one lacticinio small plant in the Vale do Paraíba area, state of São Paulo. This researches, looking for the utilization of steam and gas turbines. Both results of this economical analyses show models of two technologies turbines that supply gains.

Keywords: Análise Técnica e Econômica, Cooperativa de Laticínios, Cogeração, Custos de Produção de Vapor, Custos de Produção de Eletricidade, Technical and Economical Analysis, Laticinio Cooperative, Cogeneration, Productive Costs of Steam, Productive Costs of Electricity.

COB535 A SEMI-ANALYTICAL MODEL FOR CYLINDRICAL ICE STORAGE UNITS

Luís Edson Saraiva & Kamal Abdel Radi Ismail *

Faculdade de Engenharia e Arquitetura - Universidade de Passo Fundo

CEP 99001-970 - Passo Fundo, RS, Brasil - E-mail: saraiva@fear.upf.tche.br

*Departamento de Engenharia Térmica e de Fluidos - FEM - UNICAMP

Caixa Postal 6122, CEP 13083-970 - Campinas, SP, Brasil - E-mail: kamal@fem.unicamp.br

The objective of this paper is to present a simplified semi-analytical model to predict the thermal performance of cylindrical phase-change thermal energy storage units. The physical model is composed of an insulated vertical tank of cylindrical geometry into which is grouped a set of tubes through which a refrigerant passes, arranged in hexagonal form around the seventh central tube. The phase-change material (PCM) used is water and the refrigerant is a water-ethylene-glycol solution at low temperature. During the charging process (late night time) refrigerant circulation provides ice. This ice is to be used during the discharging cycle when water circulating provides cold water for air conditioning application. The semi-analytical model is based upon one- dimensional formulation of the phase-change heat transfer problem associated with an energy balance equation between the turbulent flow and the PCM. These coupled equations are solved by an integral approximation method. Results including solidified mass, thermal energy stored and temperature profiles are also presented and discussed.

Keywords: Thermal energy storage units, ice storage units, phase-change materials, conjugate heat transfer

COB541 AVALIAÇÃO TERMOECONÔMICA DE UM SISTEMA DE COGERAÇÃO DE INDÚSTRIA PETROQUÍMICA/THERMOECONOMIC ANALYSIS OF A COGENERATION SYSTEM OF A PETROCHEMICAL POLE

Ednildo Andrade Torres^1,2 & Sílvia Azucena Nebra²

¹Escola Politécnica/DEQ/LEN/UFBa Rua Aristides Novis, 2 Federação-Salvador-Ba CEP 40210-630, Doutorando do DE/FEM/UNICAMP ednildo@fem.unicamp.br

²Departamento de Energia - Faculdade de Engenharia Mecânica - UNICAMP - CP 6122 - CEP 13083-970 Campinas - SP sanebra@fem.unicamp.br

This paper is a study of a real system of cogeneration at a Petrochemical Pole. The analysed system has five boilers, four steam turbo-generators and one gas turbine operating in a combined cycle with total capacity of 202 MW of electrical power and 2100 t/h of steam for the process. Splitting the cogeneration process into subsystems, the exergy of each one of the energetic fluxes is calculated. It is presented the exergetical balance of each subsystem as well as the global one. The efficiency of second law of the thermodynamic of each subsystem is showed and compared, identifying where and why the losses and irreversibilities occur. The thermoeconomic costs of each one of the fluxes are calculated, and the conclusions about the cogeneration process are obtained.

Keywords: Exergy, Thermoeconomics, Petrochemical, Cogeneration, Energy. Exergia, Termoeconomia, Petroquímica, Cogeração, Energia.

COB738 ANÁLISE EXERGÉTICA DE SISTEMAS DE COGERAÇÃO E CICLOS COMBINADOS / EXERGY ANALYSIS OF COGENERATION SYSTEMS AND COMBINED CYCLES

Silvio de Oliveira Júnior

Instituto de Pesquisas Tecnológicas do Est. de São Paulo e Escola Politécnica da USP

CEP 01064-970 São Paulo, S.P. Brasil - E-mail: olivsilj@dce03.ipt.br

This paper presents a general methodology to evaluate the exergy use in cogeneration and combined cycle plants, as well as to relate the overall exergetic efficiency of the plant to the efficiencies of each module/set of equipment that compose the plant. The objective of this methodology is to quantify the thermodynamic performance of the plant and to characterise the influence of each module/set of equipment of the plant in the overall exergy consumption. The exergy analysis developed for cogeneration and combined cycle plants evaluates the exergy efficiency and the exergy destroyed in each set of equipment, and the overall cogeneration and combined cycle plants performance. The importance of each set of equipment in the overall exergetic efficiency is quantified by the use of the factor f, defined as the relation between the consumed exergy in a particular set of equipment and the consumed exergy in the plant. With the factors f_i (for each set of equipment) and the exergetic efficiencies h _i (for each set of equipment) it is possible to establish an expression that relates the overall exergetic efficiency to the factors f_i and the exergetic efficiencies h _i . This expression is useful to characterise the importance of each set of equipment in the overall exergetic efficiency and to indicate possible ways of optimising the performance of the plant. This methodology is employed to evaluate and optimise the performance of a cogeneration plant composed by a gas turbine, a Rankine cycle and an absorption chiller.

Keywords: cogeneration, combined cycle, exergy analysis

COB779 A Simplified Theory to AssesS the Burning Characteristics of a Slick of Oil on Water

Jose L. Torero

Department of Fire Protection Engineering, University of Maryland, College Park, MD20742-3031, USA-E-mail:jltorero@eng.umd.edu

An experimental technique has been developed to systematically study the ignition, flame spread and mass burning characteristics of liquid fuels spilled on a water bed. The final objective of this work is to provide a tool that will serve to assess a fuels ease to ignite, to spread and to sustain a flame, thus helping to better define the combustion parameters that affect in-situ burning of oil spills.

Keywords: In-situ burning, oil spills, mass burning, flame spread, ignition

COB912 PERSPECTIVA ECONÔMICA DO GÁS DE MADEIRA PARA GERAÇÃO TÉRMICA NO NORDESTE/WOOD GASIFICATION ECONOMICAL ANALISYS FOR THERMAL POWER GENERATION IN NORTHEAST OF BRASIL

Iberê Luiz Nodari, Sanderval Portela & *Thamy Cristina Hayashi

Departamento de Tecnologia Mecânica - CEFET/BA - R. Emídio dos Santos, s/n, Barbalho, Salvador, BA CEP: 40300-010,

E-mail: ibno@svn.com.br

*Departamento de Engenharia Química -Universidade Federal da Bahia

This paper presents results of wood gasification economic analisys concerning thermal power generation through combined cicles. Comparison is made between the gas production costs and oil barrel price. In short term, wood gasification technology and gas turbine combined cicles association is not economically competitive. In near future, however, the environmental concern, through criation of penalties like the carbon tax, proposed by the European Comission, can make use of power forests more feasible, allowing application of neutral CO₂ emission technologies. One important contribution to solve this issue involves the BIG-GT project (Biomass Integrated Gasification Gas Turbine), sponsored by international organizations associated with local enterprises. The first demonstration plant using this technology will be installed in Brazilian state Bahia.

Keywords: Wood gasification. Combined cicles. Carbon neutral emission processes. Renewable energy./ Gaseificação de madeira. Ciclo combinado. Energia alternativa. Emissão neutra de carbono.

COB1097 ANÁLISE EXERGÉTICA COMPARATIVA ENTRE UM FORNO ROTATIVO COM PREAQUECEDOR DE QUATRO ESTÁGIOS E UM COM PREAQUECEDOR E PRECALCINADOR / COMPARATIVE EXERGETIC ANALYSIS BETWEEN A ROTATY KILN WITH A FOUR-STAGE PREHEATER AND A ROTARY KILN WITH A PREHEATER AND A PRECALCINER

Rogério José da Silva

Departamento de Engenharia Mecânica, Escola Federal de Engenharia de Itajubá – EFEI

CEP 37500-000 - Itajubá-MG, Brasil – E-mail: rogerio@iem.efei.rmg.br

Sílvia Azucena Nebra

Departamento de Energia, Fac. de Eng. Mecânica - Universidade Estadual de Campinas - UNICAMP

CEP 13081-970 - Campinas-SP, Brasil – E-mail: sanebra@fem.unicamp.br

This work presents the results of a comparative exergetic analysis of plants of clinker production for the cement Portland manufacturing . The first installation is compose of the rotary kiln with a four-stage preheater and the other of a rotary kiln with preheater and a precalciner. In this analysis it is utilized the concept of rational efficiency defined by Kotas, considering the exchange of the exergy between the current of the solids and the current of the gases, as well as the transference of the mass between the solids and gases. Through of the calculus of the irreversibilities generated in each step of the process, the Grassmann’s diagram correspondent obtained, comprising the burning of the fuels in the rotary kiln burner and in the precalciner.

Keywords: Exergy; Cement Plants; Rational Efficiency; Exergetic Analysis; Irreversibilities.

Exergia; Fábricas de Cimento; Eficiência Racional, Análise Exergética, Irreversibilidade.