Electricity, hot water and cold water production from biomass. Energetic and economical analysis of the compact system of cogeneration run with woodgas from a small downdraft gasifier

Wood gasification technologies to convert the biomass into fuel gas stand out. on the other hand, producing electrical energy from stationary engine is widely spread, and its application in rural communities where the electrical network doesn't exist is very required. The recovery of exhaust gases (engine) is a possibility that makes the system attractive when compared with the same components used to obtain individual heat such as electric power. This paper presents an energetic alternative to adapt a fixed bed gasifier with a compact cogeneration system in order to cover electrical and thermal demands in a rural area and showing an energy solution for small social communities using renewable fuels. Therefore, an energetic and economical analysis from a cogeneration system producing electric energy, hot and cold water, using wooden gas as fuel from a small-sized gasifier was calculated. The energy balance that includes the energy efficiency (electric generation as well as hot and cold water system; performance coefficient and the heat exchanger, among other items), was calculated. Considering the annual interest rates and the amortization periods, the costs of production of electrical energy, hot and cold water were calculated, taking into account the investment, the operation and the maintenance cost of the equipments. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

Economic and technical feasibility study of a combined-cycle cogeneration system associated with cellulose plants

In this paper, is presented an economical and technical feasibility study of a combined cycle cogeneration system proposed to be used in a pulp plant located in Brazil, where around 95% of country's pulp production is done by the use of Kraft Process. This process allows the use of black liquor and other by-products as fuel. This study is based upon actual data from a pulp plant with a daily production of 1000 tons., that generates part of the energy demanded by the process in a conventional cogeneration system with condensing steam turbine and two extractions. The addition of a gas turbine was studied to compare electricity production level and its related costs between original system and the new one, considering that the former can use industrial by-products and firewood as fuel, when required. Several parameters related to electric generation systems operation and production costs were studied. The use of natural gas in the combined cycle, in comparison with the use of firewood in the conventional system was studied. The advantages of natural gas fuel are highlighted. The surplus availability and the electricity generation costs are presented as a function of pulp and black liquor production.

Avaliação da qualidade da água do reservatório de Itupararanga, bacia do Alto Sorocaba (SP)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo das associações de macroinvertebrados bentônicos e do sedimento dos reservatórios de Chavantes e Salto Grande (rio Paranapanema, SP, PR) e avaliação toxicológica da água e sedimento

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo sobre a utilização de energia solar no Brasil para uso residencial

Pós-graduação em Engenharia Elétrica - FEB

Projeto e implantação de pequena central de geração hidrelétrica: análise de caso

The objective of this work is to study the implantation feasibility of a small hydropower system in a rural area in Guaratinguetá. Due to its location and accessibility, and the costs involved in extending the public distribution line to the property it could turn become viable the construction of an individual electric generation system. As alternatives, a solar photovoltaic system and combustion engine-electric generator systems were considered. However, the existence of a small river inside the property, the construction of a micro hydropower plant was taken into account. The choice of the micro power hydropower plant was determined by the owner and was based on the costs. The topographic and hydrological profiles as well as the geometrical characteristics of the system, including the civil infrastructure needed and the more adequate turbine, were determined. Finally, the cost spreadsheet was set and the results were compared with those calculated for the extension of the available public distribution system

Viabilidade da geração de eletricidade a partir de fonte eólica on-shore: dificuldades e vantagens de expansão na matriz elétrica brasileira

The renewable energy sources presents an important role on the world's current context, its growing is essentially connected to the environmental issues and the energetic security, guided by the search for alternatives of energy. Among the alternative energy sources, the wind energy shows great importance in the brazilian territory, it has a great potential still unexplored and constant growth in the national electric matrix. The specific factor of generation, the conjuncture and the incentive politics influence on the expansion of wind energy in Brazil. Thus, the brazilian wind sector shows features which can be evaluated enable its developing. Keeping that in mind, the present work aims identify which are the advantages and the difficulties for the expansion of this energy source in the brazilian electric matrix. For that, the work studies the different parameters: features of electric generation of the different energy sources, incentive politics, generation costs, CO2 emission, evolution of wind energy in Brazil, the brazilian wind potential, and the regime of complementarily hydro-wind

Placement and sizing evaluation of distributed generation in electric power systems

This paper presents a methodology for the placement and sizing evaluation of distributed generation (DG) in electric power systems. The candidate locations for DG placement are identified on the bases of Locational Marginal Prices (LMP's) obtained from an optimal power flow solution. The problem is formulated for two different objectives: social welfare maximization and profit maximization. For each DG unit an optimal placement is identified for each of the objectives.

A mixed-integer LP model for the reconfiguration of radial electric distribution systems considering distributed generation

The problem of reconfiguration of distribution systems considering the presence of distributed generation is modeled as a mixed-integer linear programming (MILP) problem in this paper. The demands of the electric distribution system are modeled through linear approximations in terms of real and imaginary parts of the voltage, taking into account typical operating conditions of the electric distribution system. The use of an MILP formulation has the following benefits: (a) a robust mathematical model that is equivalent to the mixed-integer non-linear programming model; (b) an efficient computational behavior with exiting MILP solvers; and (c) guarantees convergence to optimality using classical optimization techniques. Results from one test system and two real systems show the excellent performance of the proposed methodology compared with conventional methods. © 2012 Published by Elsevier B.V. All rights reserved.

Relationship between age of waste and natural electric potential generation in Sanitary Landfill

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pyrolysis and auto-gasification of black liquor in presence of ZnO: An integrated process for Zn/ZnO nanostructure production and bioenergy generation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Line-pack management for producing electric power on peak periods

The distribution of natural gas is carried out by means of long ducts and intermediate compression stations to compensate the pressure drops due to friction. The natural gas compressors are usually driven by an electric motor or a gas turbine system, offering possibilities for energy management, one of these consisting in generating energy for use in-plant or to commercialize as independent power producer. It can be done by matching the natural gas demand, at the minimum pressure allowed in the reception point, and the storage capacity of the feed duct with the maximum compressor capacity, for storing the natural gas at the maximum permitted pressure. This allows the gas turbine to drive an electric generator during the time in which the decreasing pressure in duct is above the minimum acceptable by the sink unit. In this paper, a line-pack management analysis is done for an existing compression station considering its actual demand curve for determining the economic feasibility of maintaining the gas turbine system driver generating electricity in a peak and off-peak tariff structure. The potential of cost reduction from the point of view of energy resources (natural gas and electric costs) is also analyzed. (C) 2010 Elsevier Ltd. All rights reserved.

Multi-objective evolutionary particle swarm optimization in the assessment of the impact of distributed generation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An approach of optimal sensitivity applied in the tertiary loop of the automatic generation control

This paper proposes an approach of optimal sensitivity applied in the tertiary loop of the automatic generation control. The approach is based on the theorem of non-linear perturbation. From an optimal operation point obtained by an optimal power flow a new optimal operation point is directly determined after a perturbation, i.e., without the necessity of an iterative process. This new optimal operation point satisfies the constraints of the problem for small perturbation in the loads. The participation factors and the voltage set point of the automatic voltage regulators (AVR) of the generators are determined by the technique of optimal sensitivity, considering the effects of the active power losses minimization and the network constraints. The participation factors and voltage set point of the generators are supplied directly to a computational program of dynamic simulation of the automatic generation control, named by power sensitivity mode. Test results are presented to show the good performance of this approach. (C) 2008 Elsevier B.V. All rights reserved.

Behavior of bromide in the photoelectrocatalytic process and bromine generation using nanoporous titanium dioxide thin-film electrodes

In this study, the photoelectrocatalytic behavior of bromide and generation of bromine using TiO2 was investigated in the separate anode and cathode reaction chambers. Our results show that the generation of bromine begins around a flatband potential of -0.34 V vs. standard calomel electrode (SCE) at pH 3.0 under UV illumination and increases with an increase in positive potential, finally reaching a steady-state concentration at 1.0 V vs. SCE. Maximum bromine formation occurs over the range of pH 4-6, decreasing sharply at conditions where the pH > 7. © 2003 Elsevier Ltd. All rights reserved.