Psce 2011 Article final
part of the methodology. The current method for solid biomass
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PSCE 2011 Article final
part of the methodology. The current method for solid biomass operational consumption measurement is usually derived from the amount of steam produced versus the constant: Tons of biomass per Tons of steam. This last term is a very common parameter available at the manufacturer boiler data sheet. The amount of produced steam is measured via temperature, pressure and flow transmitters. It is usually integrated into Tons/hour and is available as a digital data at the boiler control system. However, this current practice in cogeneration industry is too simplistic while it premises the boiler performance as flat for any amount of steam produced per hour. Thus, the proposal is to measure the real biomass consumption of the boiler per unit of time. This is not an available data at current 6 biomass cogeneration systems. The measurement of biomass consumption when it is in liquid or gas state is quite simple to obtain using available known flow meters. But when talking about solid biomass, specifically sugarcane bagasse which presents variable density in different feeding situations, a precise measurement process can be difficult to obtain. Therefore, it is needed to establish a routine that can help each cogeneration owner to find its unique biomass feeding standard. This routine is composed by the following steps: Step 1: Elaborate the biomass feeding diagram for the boiler. Step 2: Study the dosing system technology. Step 3: Prepare an experiment of biomass flow measurement within a period of time. Step 4: Establish adequate parameters for measurement time base and number of samples. Step 5: Execute the experiment. Step 6: Construct the behavior curve for biomass feeding. Establish dependence relations between feed rate and other stated variables. Step 7: Model the measurement system using available instrumentation. Choose instruments capable to transmit data in a real time base using a predetermined industry control system communication protocol for field instrumentation. Step 8: Implement the measurement system. Step 9: Execute empirical tests. Step 10: Validate the biomass feeding procedure. The proposed steps are based on the so called PDCA cycle and are intended to cover the large variety of feeding systems for biomass fired boilers. 5) Measurement integration After measurement of all terms needed to obtain the operational energy efficiency, it is needed to integrate them into the cogeneration control system using the calculation equations. There is a wide range of supervisory and control system products compliant with this need and capable to keep a database accessible through TCP/IP protocol connections. Thus, the efficiency data would be available in typical computer networks, accessible to others through VPN client links or even disclosed through the owner website. VI. C ONCLUSIONS The proposed methodology is intended to work as a calculation and measurement guide for cogeneration owners interested to manage the overall energy efficiency of their plants. It permits them to use it on continual improvement programs as proposed by ISO. It intends also to work as real time efficiency data disclosure from cogeneration agents to others, what could bring this issue to public domain. After all, the presumed benefits of utilization of the here proposed methodology are listed below. - Obtaining of a supply side energy management tool for power plants; - M&V application for energy savings accountability; - Optimization of energy production costs; - Low carbon policy achievement; - Real time efficiency database of cogeneration plants pushing public policy improvement (PURPA, etc.); and - Smart Grid contribution on transparency for public agents and customers. A study case is being carried out for a group of four sugar cane bagasse cogeneration plants in Brazil. All the stated points of the methodology are being observed so for calculation as for measurement. The routine for achievement of bagasse feeding standard for each plant is going to be applied. Many other challenges are expected during the experiments implementation, measurements execution, and so on. However, the presentation of here stated ideas can be useful for other similar initiatives in other generation units around the world. A further possible work after the application of the methodology for small cogeneration plant groups is the standardization of measurement routine and accuracy, that would permit to achieve accreditation for the applicability of this process to the entire cogeneration sector. After the establishment of a cogeneration historic database along the time, advances can be better controlled through future public policies like technology substitution incentives. Some emerging solutions for energy efficiency improvement are listed below. - Process waste heat recovery applications; - Substitution of fossil fuels due to Co-firing with biomass; - Biomass gasification creating combined cycle possibility for biomass; - Enzymatic Hydrolysis raising biomass energy transformation efficiency; and - Biomass Torrefaction raising calorific power [11]. VII. A CKNOWLEDGMENT The authors gratefully acknowledge the contributions of: D. M. Neto, for his contribution to process and thermodynamic analyses and A Nissimoff, for his contribution to grammar review. VIII. R EFERENCES [1] Energy Policy Act of 2005, Public Law 109-58-Aug.8, 2005.109 th Congress of the United States of America, 2005. [2] Energy Independence and Security Act of 2007. 110 th Congress of the United States of America, 2007. [3] IEA – International Energy Agency, “Towards a more energy efficient future – Applying indicators to enhance energy policy”, OECD/IEA, 2009. [4] U.S. Environmental Protection Agency, “Cogeneration Unit Efficiency Calculations – Technical Support Document for the Final Clean Air Interstate Rule”, OAR-2003-0053, March 2005. [5] Directive 2004/8/EC of the European Parliament and of the Council, Official Journal of the European Union, 21.2.2004. [6] Commission of the European Communities, “Action Plan for Energy Efficiency: Realising the Potential”, COM(2006)545 final, Brussels, 19.10.2006. [7] COGEN Europe, “Response to the European Commission consultation on the review of the Energy Efficiency Action Plan”, 16.07.2009. [8] ANEEL – Electric Energy National Agency, “Normative Resolution nº235”, Brazil, November 14, 2006. 7 [9] ISO/DIS 50001, “Energy management systems – Requirements with guidance for use”. Draft International Standard, International Organization for Standardization, 2010 [10] G. J. Van Wylen, “Fundamentals of Classical Thermodynamics”. São Paulo: portuguese translation of 4 th american edition, Edgar Blücher Ltd., 1995, p. 608. [11] EPRI – Electric Power Research Institute, “Generation 2009 Annual Overview”, March 2010, p. 61. IX. B IOGRAPHIES Download 328.84 Kb. Do'stlaringiz bilan baham: |
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