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Análisis Termodinámico de un Sistema de Cogeneración con Gasificación del Licor Negro Thermodynamic Analysis of a Cogeneration System with Black Liquor Gasification  [cached]
Paulo R Santos,Francine M Fábrega,José Vicente H d’Angelo
Información Tecnológica , 2008,
Abstract: Se presenta el análisis termodinámico de un proceso de cogeneración de energía con gasificación del licor negro, utilizando balances de exergía para identificar y cuantificar las principales irreversibilidades presentes. Se realizó una simulación del proceso de cogeneración con un simulador comercial, a partir de la cual fue posible realizar el balance de exergía del sistema. Se evaluó la influencia de la composición de los gases obtenidos en el gasificador sobre las pérdidas exergéticas en el proceso. Las condiciones operacionales del gasificador de licor negro que contribuyen a reducir la concentración de estos compuestos responsables de las pérdidas de exergía, son la baja temperatura (700°C) y la baja presión (200 kPa). El análisis mostró útil para determinar de viabilidad técnica del proceso alternativo de generación de energía a través de la gasificación del licor negro. This work presents a thermodynamic analysis of a cogeneration energy process with black liquor gasification obtained in pulp and paper industries, using exergy balances to identify and quantify the main irreversibilities in the process. The cogeneration process was analyzed using a commercial simulator from which it was possible to develop the exergy balance. The influence of the composition of the gases produced in the gasifier over the exergy losses in the process was evaluated. The most appropriated operating conditions in the gasifier to reduce the concentration of these components, which are responsible for the exergy losses are the low temperature (700 oC) and the low pressure (200 kPa). The analysis showed to be useful to determine the technical viability of this alternative process of energy generation using black liquor gasification.
Heat Integration Study on Biomass Gasification Plant for Hydrogen Production  [PDF]
Murni M. Ahmad,Mohd F. Aziz,Abrar Inayat,Suzana Yusup
Journal of Applied Sciences , 2011,
Abstract: The world is facing global warming crisis and environmental problem due to usage of fossil fuels as major energy source. Therefore, the potential of hydrogen as an alternative, sustainable, renewable source of clean energy is highly regarded. This project aimed to develop a process simulation model of a heat-integrated flowsheet for a biomass gasification plant for hydrogen production using ASPEN PLUS software. Heat integration study has been performed on the plant flowsheet using pinch analysis and was carried out in SPRINT, The University of Manchester Process Integration Software. The minimum temperature difference was set to be 10 K. Based on the study, it was found that the minimum hot utilities required was 0.1642 kW while the minimum cold utilities required was 0.0545 kW. The maximum heat recovery from the process was 0.8413 kW. Using problem table algorithm, the pinch temperature was determined to be at 628.5C. Three heat exchangers were proposed in the heat exchanger network design. Calculations recorded savings of approximately 72% in hot utilities and 88% in cold utilities via the heat integration analysis.
Cogeneration and Heat Recovery in the Industrial Process
Budin, R.,Miheli?-Bogdani?, A.,Vujasinovi?, E.
Kemija u Industriji , 2007,
Abstract: Related to energy requirements for non-cellulose i. e. polyester production as an energy-intensive process, potential saving options are proposed. From the process data, it is evident that unit operations need electric and thermal energy in significant amounts. At the same time, improved energy management could be realized by applying a combined heat and power system (CHP) instead of the usually used process with separate heat and power production. In addition, the boiler flue gases with a sufficiently high outlet temperature could be used for combustion air preheating.Considering industrial process data, a calculation and comparison between the primary energy demand for conventional, CHP system and flue-gas heat recovery is presented. Comparison between separate heat and electricity production i.e. the conventional system with an overall efficiency of 55.6 % and CHP with efficiency of 85 %, shows an absolute efficiency increase of 29.4 %. Using an air preheater for combustion air temperature increasing saves 5.6 % of the fuel and at the same time diminishes thermal pollution because the exhaust flue-gas temperature becomes 77.3 °C instead of 204 °C. Conclusively, cogeneration and flue-gas heat recovery presentsfuel savings, which also implies economic and environmental benefits.
Biomass Cogeneration Technologies: A Review  [PDF]
Theleli Abbas, Mohamad Issa, Adrian Ilinca
Journal of Sustainable Bioenergy Systems (JSBS) , 2020, DOI: 10.4236/jsbs.2020.101001
Abstract: Currently, fossil fuels such as oil, coal and natural gas represent the prime energy sources in the world. However, it is anticipated that these sources of energy will deplete within the next 40 - 50 years. Moreover, the expected environmental damages such as the global warming, acid rain and urban smog due to the production of emissions from these sources have tempted the world to try to reduce carbon emissions by 80% and shift towards utilizing a variety of renewable energy resources (RES) which are less environmentally harmful such as solar, wind, biomass, etc. in a sustainable way. Biomass is one of the earliest sources of energy with very specific properties. In this review, we present the different cogeneration systems to provide electrical power and heating for isolated communities. It has been found that the steam turbine process is the most relevant for biomass cogeneration plants for its high efficiency and technological maturity. The future of CHP plants depends upon the development of the markets for fossil fuels and on policy decisions regarding the biomass market.
Flexibility and uncertainty in agribusiness projects: investing in a cogeneration plant
Dias, Augusto Cesar Arenaro e Mello;Bastian-Pinto, Carlos de Lamare;Brand?o, Luiz Eduardo Teixeira;Gomes, Leonardo Lima;
RAM. Revista de Administra??o Mackenzie , 2011, DOI: 10.1590/S1678-69712011000400005
Abstract: energy generation from biomass has become a source of increasing interest due to growing environmental concerns and the depletion of the world's fossil fuel reserves. in this paper we analyze a sugar and ethanol producing plant in brazil which has both the option to expand and to add a cogeneration unit to allow the sale of surplus energy, generated by burning sugar cane bagasse, where the existence of the second option is conditional to the exercise of the first option. we model sugar, ethanol, and electricity prices as geometric mean reverting processes and apply the real options approach to determine the value of these managerial flexibilities, considering that these options have three distinct underlying assets. the option to expand production is a function of the expected future prices of sugar and ethanol, while, on the other hand, the decision to invest in the cogeneration plant will depend on the future prices of energy. both decisions are modeled as american compound options over their respective underlying assets. the model is then solved using the non-censored binomial mean reverting lattice proposed by bastian-pinto, brand?o, and hahn (2010) using the software dpltm. the results indicate that a significant value can be derived from the flexibility to choose the optimal timing of investment in both options: the investment in the cogeneration unit adds an amount equivalent to the value of the expanding sugar and ethanol production, and represents up to 44% of the project's static npv of r$ 195.9 million. we conclude that given that only half of the sugar cane crushing mills currently have cogeneration units installed and given the increasing demand for clean and renewable sources of energy, this may indicate there is a significant potential for investment and further development of bioelectricity cogeneration power plants, and even in the retrofit of older cogeneration units, and that government incentives have been effective in contributing to this develo
Flexibility and uncertainty in agribusiness projects: investing in a cogeneration plant.
Augusto Cesar Arenaro e Mello Dias,Carlos de Lamare Bastian-Pinto,Luiz Eduardo Teixeira Brand?o,Leonardo Lima Gomes
Revista de Administra??o Mackenzie , 2011,
Abstract: Energy generation from biomass has become a source of increasing interest due to growing environmental concerns and the depletion of the world’s fossil fuel reserves. In this paper we analyze a sugar and ethanol producing plant in Brazil which has both the option to expand and to add a cogeneration unit to allow the sale of surplus energy, generated by burning sugar cane bagasse, where the existence of the second option is conditional to the exercise of the first option. We model sugar, ethanol, and electricity prices as geometric mean reverting processes and apply the real options approach to determine the value of these managerial flexibilities, considering that these options have three distinct underlying assets. The option to expand production is a function of the expected future prices of sugar and ethanol, while, on the other hand, the decision to invest in the cogeneration plant will depend on the future prices of energy. Both decisions are modeled as American Compound Options over their respective underlying assets. The model is then solved using the non-censored binomial mean reverting lattice proposed by Bastian-Pinto, Brand o, and Hahn (2010) using the software DPLTM. The results indicate that a significant value can be derived from the flexibility to choose the optimal timing of investment in both options: the investment in the cogeneration unit adds an amount equivalent to the value of the expanding sugar and ethanol production, and represents up to 44% of the project’s static NPV of R$ 195.9 million. We conclude that given that only half of the sugar cane crushing mills currently have cogeneration units installed and given the increasing demand for clean and renewable sources of energy, this may indicate there is a significant potential for investment and further development of bioelectricity cogeneration power plants, and even in the retrofit of older cogeneration units, and that government incentives have been effective in contributing to this development.
Energy-Exergy, Environmental and Economic Criteria in Combined Heat and Power (CHP) Plants: Indexes for the Evaluation of the Cogeneration Potential  [PDF]
Marco F. Torchio
Energies , 2013, DOI: 10.3390/en6052686
Abstract: In the first part of this work, combined heat and power (CHP) criteria pertaining to energy, exergy, environmental (pollutant emission) and economic aspects, have been investigated and compared. Although the constraints in legislation usually refer to energy efficiency, primary energy savings and greenhouse gas savings, other criteria should also be taken into account in order to obtain a better evaluation of a cogeneration plant. Here particular attention has been paid to saving indexes for both an individual CHP-unit and for a CHP-system, that is the complete system with all the cogeneration units and the auxiliary plants necessary to cover the users’ demand. Five indexes, named potential indexes, have been introduced to evaluate the cogeneration potential: one for energy saving, one for exergy, two for environmental aspects (global and local scale) and one for economic aspects. Finally, some indexes analysed in the paper have been applied to a case study concerning a district heating cogeneration system, and the different behaviour of the energy-exergy, environmental and economic aspects has been discussed.
Steam Turbine Assisted Cogeneration systems
?arisky Marián
Acta Montanistica Slovaca , 2004,
Abstract: Searching for the best way of improving using systems of production electrical energy and heat is part of an intensive development in the field of energetic. Using steam turbines in the cogeneration system is very important step at increasing the effection not only of the whole system, but of the gas turbine as well. The advantages and the characteristic features of the system are shown in the article.
Energy-Saving and Economical Evaluations of a Ceramic Gas Turbine Cogeneration Plant  [PDF]
Satoru Okamoto
Open Journal of Energy Efficiency (OJEE) , 2013, DOI: 10.4236/ojee.2013.22012
Abstract:

A ceramic gas turbine can save energy because of its high thermal efficiency at high turbine inlet temperatures. This paper deals with the thermodynamic and economic aspects of a ceramic gas turbine cogeneration system. Here cogeneration means the simultaneous production of electrical en-ergy and useful thermal energy from the same facility. The thermodynamic performance of a ceramic gas turbine cycle is assessed using a computer model. This model is used in parametric studies of performance under partial loads and at various inlet air temperatures. The computed performance is compared to the measured performance of a conventional gas turbine cycle. Then, an economic evaluation of a ceramic gas turbine cogeneration system is investigated. Energy savings provided by this system are estimated on the basis of the distributions of heat/power ratios. The computed economic evaluation is compared to the actual economic performance of a conventional system in which boilers produce the required thermal energy and electricity is purchased from a utility.

Assessment of the Performance and Potential Export Renewable Energy (RE) From Typical Cogeneration Plants Used in Palm Oil Mills
A.B. Nasrin,N. Ravi,W.S. Lim,Y.M. Choo,A.M. Fadzil
Journal of Engineering and Applied Sciences , 2012, DOI: 10.3923/jeasci.2011.433.439
Abstract: Cogeneration or combined heat and power is one of the proven economically approaches to produce >1 useful of energy simultaneously from the single energy source. Malaysia is fortunate to have plentiful supplies of biomass mainly from milling sector of the oil palm industry. Due to that biomass based cogeneration plant is used in palm oil mills in Malaysia to generate steam and electricity. In this study, the assessment of cogeneration plant efficiency was conducted in six palm oil mills with processing capacities ranged from 20-54 ton h-1. In addition to determining boiler, turbine and overall cogeneration plant efficiencies, the study also focused on developing the baseline data of energy utilization and generation in palm oil mills and estimated the potential excess energy from the available palm biomass generated in palm oil mills. It was found that most of the boilers and turbines used in palm oil mills have moderate efficiencies which were <80 and 35%, respectively, compared to conventional operational unit used in fossil based power plants. Besides that, most of the mills used excessive specific energy to generate steam and electricity compared to the optimum industrial designed data. In terms of the potential excess electricity, it was found that the potential excess electricity that could be generated for export ranged from 113 kW for the 20 ton h-1 mill to 900 kW for the 54 ton h-1 mills. The details of technical findings and potential economic benefits are discussed in this report. As the project is in line with the Government s programme in promoting renewable energy and energy efficiency, millers should take this opportunity to operate the cogeneration plant in an energy efficient manner, earn additional income besides managing the waste in an environmental friendly approach.
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