Avaliação experimental de eficiência térmica de um recuperador de calor e caldeira em um sistema de cogeração

Pós-graduação em Engenharia Mecânica - FEB

Estudo da viabilidade técnica, econômica e ambiental da substituição de um banco de resistências elétricas de aquecedores por uma caldeira alimentada por biomassa de paletes residuais na indústria de laminação

Given the increasing demand for fossil fuels to power the engines of the global economy, and also the slow process of synthesis of oil, it becomes necessary to develop new sources of renewable energy in addition to improve promising sources that already exist, turning them competitive. Based on this, biomass is shown very promising between the most popular energy sources due to its availability, applicability, and above all, the fact of not emitting green house gases when analyzing the whole carbon cycle. In this sense, this work presents, through an environmental, technical and economic analysis, the impact in an aluminum mill of replacing the use of electricity, in one process, by a boiler fueled with biomass from waste process of packaging the finished product with pallets. Thus, besides the reduction of CO2 emissions, financial gains are targeted, since the main goal of the corporations that require such power is to maximize its profits

Análise de ciclo avançado com seqüestro de carbono

The energy is considered one of the most important elements in the human´s life providing the survival as well as the well being. Nowadays, the technologies destined to generate power burn fossil fuels which pour gases (carbon dioxide among them) that contribute to the global warming phenomenon. Several research groups and universities have been studying different methods for generating power with low carbon dioxide emissions, including the possibility of burning zero-carbon fuels. In this text, it has been put attention to the Advanced Zero Emission Power Plants (AZEP) which separate the CO2 (from the gases involved in the power generation), compress it, dehydrate it and store it in appropriate reservoirs. The goal of this study was to find a possible solution to produce CO from CO2, activated by solar energy; the reaction between CO and steam generates a syngas comprised of H2 and CO2, which can be separated by chemical and/or physical processes. The text also contains a study concerning the compressed air energy storage power plant (CAES) and come up with its modification to C[CO2]ES. This power plant stores CO2 directing it to a reverse combustion process to produce CO which is headed to a syngas reactor to produce CO2 and H2. Hydrogen is separated and carried to the thermal cycle to generate power with low carbon emissions

Avaliação dos gases de efeito estufa a partir do carvão

This paper addresses the context of emissions of Greenhouse Gases (GHG) from activities related to Coal, called fugitive emissions. The survey of factors, development, analysis, and suggestions for controlling emissions are conducted in order to reduce risks to the environment and people around it. The greenhouse gases absorb radiation, emitted by the Earth’s surface, and hinder their escape into space. This process is essential to terrestrial life. Increasing the concentration of those gases in the atmosphere has led to an increase in the terrestrial temperature. A selection of processes that emit gases and the study and development of calculations for measuring fugitive emissions applied in different sources from coal are performed. The greenhouse gases can be released from the extraction, processing, storage, and transportation of fossil fuels to the end consumer. Coal has 4 main fugitive factors: mining, post-mining, oxidation at low temperature, and uncontrolled combustion. The coal formation process produces methane (CH4) and carbon dioxide (CO2), being the methane, the main greenhouse gas from the coal mining and handling. The types of activities and the weight of each in the issuing process are observed. It is also made comparisons between the countries with the highest emissions rates. Are evaluated what has been done and what is needed to decrease emissions, for example the use of gas as an alternative fuel for energy generation

Estudo e modelagem 3D de um cabeçote para um motor monocilíndrico, 400cc, 4 T

The cylinder head contains the combustion chamber for the air-fuel mixture and the intake and exhaust valves, the valve guide and the valve seat. The cylinder head also is a support for the camshaft and valve rocker. The holes where the spark plugs are connected are designed to fit the better place in the combustion chamber. The cylinder heads often are manufactured using materials such as aluminum and cast iron. The cooling fins located in the outside of the cylinder head are designed for a good heat transfer and therefore their dimensions and positioning are important. This work aims the calculation for a cylinder head to be installed in a 400 cc displacement, gasoline powered, four stroke, single cylinder engine. According to the displacement it will be analyzed the combustion chamber, the intake and exhaust valves, as well as the camshaft and rocker arms. This also a work to help to accomplish the design of a single cylinder engine, where the alternatives parts, cylinder block and crankcase are all already machined and assembled in this campus

Avaliação do potencial de microgeração em despacho econômico para atendimento aos requisitos de etiquetagem de edifícios

The discussions about the energy rationalization are gaining more and more space on the everyday of engineers and other professionals in the field of energy. A greater focus is being tied to commercial buildings, because they are one of the biggest responsible for the high energetic expenditure according to the National Energetic Balance, especially by the use of air conditioners for the people’s thermal comfort. Such finding made INMETRO to develop a building labeling procedure through th National Program of Electric Energy Conservation in Buildings; by means of this systematic, the built areas are classified by levels that go from A(the best) to E(the worst), taking into account envelopment, illumination system and air conditioning. A bonus process based on water rationalization, use of renewable energy sources, cogeneration systems or technical innovations, allows the classification to be changed up to one level. A study made exactly on a commercial building, the building of Foundation for Technological and Scientific Development located inside of the College of Engineering of Guaratinguetá, sought to identify technical/economic alternatives for the building certification and appealed to the bonus based on water rationalization. The present study is based on analysis of deploying a cogeneration system formed by internal combustion engine and an absorption refrigeration system as bonus alternative, so that the costs are analyzed regarding energy consumption and use of the motor. With the calculations and results, the viability of the building to receive a bonus from INMETRO through its National Program for Energy Conservation in Buildings is studied and concluded from this study whether or not you can get a better level of energy efficiency for the building in question... (Complete abstract click electronic access below)

Rerrefino de óleo lubrificante usado

The lubricant oil used in engines of internal combustion must be, periodically, changed. Its mainly function in the engines is to reduce the friction between the pieces, but its presence also promotes the cleanness and the refrigeration of the equipment. These attributions, at the end of some cycles of operation, make the oil to be dirty, that is, full of contaminating substances such as water, gasoline, diesel, additives, oxidized hydro-carbons and rests of metals, not being recommended, therefore, its discarding in the environment. Thus, all the used lubricant oil that leaves the automobiles engine has been thrust, waiting for a solution. The pollution generated by the discarding of a ton of used oil per day in the soil or in the rivers is equivalent to a domestic sewer of 40 thousand of people. The indiscriminate burning of the used lubricant oil generates significant emissions of metallic oxides, besides other toxic gases, like the dioxin and sulphur oxides. In this context, the mean objective of this essay was to effectuate the rerrefine of the used lubricant oil, aiming the increase of its life cycle and consequently contributing for the reduction of the environmental pollution. According to the used process, it was possible to get a rerrefine oil, of good quality, which physicistchemistries properties are in compliance with the norms of NBR and ASTM

Analise técnico-econômica de um gaseificador Downdraft e de filtros para limpeza de gás de síntese

The biomass gasification systems have been used for a long time and prove to be a good alternative to the generation of energy problems. This type of management requires a simple installation and maintenance which gives them a high availability. In Biomass project via Call CTEnerg 33/2006-1, funded by the Ministry of Science and Technology - MCT - Brazil, the Group Energy Systems Optimization – GOSE - at FEG - UNESP built and tested two prototypes of gasifiers. These is fed with 25 kg / h of dry wood (chips), and 50 Nm3 / h of air to produce gas at a flow rate of approximately 70 Nm3 / h of wood (syngas) at a temperature approximately 600 ° C. In this work of graduation, studies were conducted on the materials used in both the gasifier as well as cleaning the filter synthesis gases. The system of gas cleaning and conditioning is vital to ensure the life of the Internal Combustion Engine. In this case the studies of different filters for small gasification systems (properties, materials used, characteristics, types, etc.) are very relevant to its use in the prototype of the college campus. Were also performed a technical and economic analysis of a cogeneration system that consists in the combination of the downdraft gasifier studied in this work, an internal combustion engine, two heat exchangers and a SRA (absorption system refrigerator). Were calculated the costs of electricity generation, hot water and cold water. Finally, we analyzed the economic feasibility of the project

Cogeração em uma indústria automobilística

The search for energy efficiency improvement is a common concern in many companies. Cogeneration is a well known technique but not so spread in Brazil, despite its potential for energy costs reduction through heat recovery from prime movers. In this work, a preliminary technical and economic study is carried out for a cogeneration plant application in an automotive industry of São Paulo. Though mathematics modeling, three 2435 kW internal combustion engines are selected. When compared to the current status (no cogeneration), annual savings of about 2,2 MR$ are obtained, resulting a almost 3 years payback

Análise dos limites de inflamabilidade a partir de uma visão de pressões parciais de biocombustível

In this work concepts of flammability limits of anhydrous and hydrated ethanol to pressures below atmospheric, using the Dalton model for gaseous mixtures. Theoretical and experimental methods for determining the boundaries and the influence of parameters such as concentration, temperature and pressure were introduced. Analyzes from partial pressures of fuel vapor and correlations with temperature and total pressure were made. Finally presents an overview of aviation fuels, their requisites and trends in the use of biofuels in commercial aviation industry

Estudo de temperatura de plasma de álcool através de espectroscopia de emissão natural radical C2*

Non-intrusive methods of diagnosis, such as spectral analysis of the radiation emitted by the system, have been used as a viable alternative for determining the temperature of combustion systems. Among them, the determination of temperature by natural emission spectroscopy has the advantage of requiring relatively simple experimental devices. Once Chemiluminescent species are formed directly in the excited state, the collection and recording of radiation emission spectrum is enough to determine the temperature (CARINHANA, 2008). In this study we used the process of making direct comparisons between the experimental spectra obtained in the laboratory from the plasma of alcohol, and the theoretical spectra plotted from a computer program developed at the IEAv. The objective was to establish a fast and reliable method to measure the rotational temperature of the radical C2*. The results showed that the temperature of the plasma, which in turn can be taken as the rotational temperature of the system, is proportional to the pressure. The temperature values ranged from ca. 2300 ~ 2500 K at a pressure of 19 mmHg to 3100 ~ 3500 K for the pressure of 46 mmHg. The temperature values are somewhat smaller when we consider the theoretical spectrum as a Lorentzian curve. The overlap of the spectra was better when using the profile curve, but still were not exactly superimposed. The solution to improve the overlap of the theoretical with the experimental spectra is the use of a curve that has the convolution of two profiles analyzed: Lorentzian and Gaussian. This curve is called the Voigt profile, which will also be implemented by programmers and studied in a next work

Análise exergética e ecológica de um sistema compacto de cogeração operando com gás de síntese

The aim of this work is to make a qualitatively and ecologically evaluation of a compact cogeneration system that operates with synthesis gas obtained from a gasifier. Using the Eucalyptus Biomass as fuel, that passes through a wood gasifier (Drowndraft type) and supply the internal combustion engine. The compact cogeneration system is composed of two heat exchangers, an energy generator connected to an internal combustion engine and an absorption refrigeration system. The complete system is installed in the laboratory from the Energy Department at the University of Guaratinguetá. By the analysis related to the First and Second Thermodynamic Laws applied in this system, was possible to identify the mass flows in each point, energetic efficiency, irreversibility and exergetic efficiency. The components that have the biggest irreversibilities are the gasifier, followed by the internal combustion engine, which should be focused in future improvements. The system efficiency in energetic basis is 51,84% and in exergetic basis is 22,78%. Using the ecologic efficiency methodology was possible to identify the emissions rates, the pollution indicator associated to the combustion of the synthesis gas in the internal combustion engine. The ecologic efficiency considering the energectic analysis is 91,73%, while considering the exergetic analysis, 83,65%. It is concluded that the use of the synthesis gas in a compact cogeneration system is viable from the technical and ecological point of view, making possible to generate energy for isolated communities and promoting the decentralized electricity generation

Determinação de temperatura de chamas por espectroscopia de espécies quimioluminescentes

In a combustion process involving fossil fuels, there is the formation of species Chemiluminescent, especially CH*, C2* and OH*, whose spontaneous emission can be used as a diagnostic tool. In the present work, mapping and determination of the rotational temperature of the species CH* produced in flames on a burner fueled by Liquefied Petroleum Gas (LPG) was carried out. This study is part of a project involving the characterization of supersonic combustion in scramjets engines, whose study has been conducted in the hypersonic shock tunnel IEAv laboratories. The technique used was the natural emission spectroscopy, which has as main advantage of being non-intrusive. The rotational temperature determination was made using the Boltzmann method, whose principle is to relate the emission intensity of the species to the temperature by means of spectroscopic constants established.The temperature values were determined from the analysis of electronic bands AX and BX of the radical CH*. In order to confirm the results of flame temperatures obtained by the natural emission technique, was also used the technique of line reversal sodium. The results of both techniques showed that the temperature of the flames investigated is about 2500K a 2700K

Análise dinâmica e estrutural de virabrequim

This paper deals with static analysis and dynamic stress of an ensemble crank and crankshaft, contained within a combustion engine of 4 cylinders. Aimed to illustrate procedures for computer-aided analysis having as goal the optimization of components according to the need for the market demand. Thus, to work in static and dynamic analyzes were summarized the basic theory involved in the calculations and analyzes necessary actuation forces and held a brief introduction about the manufacturing process and forging. Subsequently, it was applied with the use of software in a case the crankshaft, to obtain the performance and structural dynamic thereof. There was a conservative result and critical points in the fillet of the crankshaft bearing, as well as for lubrication hole. It was concluded that there are possibilities for improvements in the manufacturing process and design optimization in order to provide lower criticality and a more robust part

Análise cinemática e dinâmica para conversão de um VW saveiro em veículo elétrico

This work aims to kinematic and dynamic analysis of a VW Saveiro in order to estimate the power requested to the engine with the imposed movement conditions. Thus, the study will be the basis to the specification of the electric engine, on the conversion of the internal combustion vehicle into electric one. First of all, a literature review was done in order to understand the state of the art for this issue and come up with the technical features of the vehicle in question. The next step is the identification and calculation of all forces acting on the prototype in motion, from 0 to 120 km/h, in intervals of 10 km/h, under the defined conditions of path and time. Then, were determined the values of the torque and rotation of the components from the transmission system, as well as the engine power, for each speed range. The results show the most influential forces on the resistence of the movement in each speed range, and the behavior of the torque curve is verified. Finally, it was also analyzed the implementation of pinwheels on the frontal area of the vehicle, in order to convert wind energy into electrical energy to supply the lighting subsystem of the vehicle and the proposal was validated. Limiting the maximum speed of the vehicle to 90 km/h, it was finally concluded that the power of the electric engine should be 40 HP