Air cooled condensers, usually defined with the acronym ACCs, are the most widely used components in power production plants in which steam it’s produced to be then expanded in the turbine obtaining electrical power. Among the various substances present in nature, water has the best heat transfer properties, but in some cases due to its poor availability and importance as human resource and as agriculture support, it’s often preferable to use air as coolant; the use of air cooled condenser lead to different advantages as: the possibility to build the power plant in places without the presence of water, lower investment and maintenance costs and the possibility to not being subject to regulations that limit the exploitation of waterways. The scope of the air cooled condenser is to condense the steam flow coming from the steam turbine exhaust utilizing ambient air, in order to recycle the amount of the cycle water; then the condensate can be utilized to satisfy some final thermal users (for instance in co-generative plants) and/or be sent to the boiler in order to be re-evaporated and continue with the plant cycle process. During my stage at an engineering consultancy office for air cooled condenser in Switzerland, an important Italian society ask us to help them to find a possible concrete solution at their problems. Their waste to energy power plant, during steam turbine maintenance and in case of full rejection of the final thermal users, must to reject all the steam flow coming from the boiler into the atmosphere because their actual installed ACC can’t operate in pressure (the boiler generates a steam flow of 380 [ton/h] at 5 bar(a)). So, our scope is to project a new air cooled condenser that must work in addition and in parallel with the installed one, at working conditions of 5 bar(a) and that can operate under vacuum until 120mbar(a). To reach this aim, the only available choice is to utilize an ACC multi-rows which can withstand in pressure and under vacuum operating conditions. For the design of the ACC, I created an Excel tool that can estimate the needed heat transfer surface, the outlet air temperature, the needed volumetric air flow, the overall heat transfer coefficient of the tube bundles, the total fans electrical power consumption, and the other fundamental parameters, considering all the tubes characteristics (given to me by the company), design parameters and verifying all the design constraints. Once the air cooled condenser design has been defined, I analyse its operation under different working conditions and I created a control logic unit that can regulate the fans rotational speed needed to condensate the actual steam flow at that precise conditions. This control logic derives from the experiences I have gained in the field during inspective visits at different waste to energy plants placed in the north of Italy. Air cooled condensers, usually defined with the acronym ACCs, are the most widely used components in power production plants in which steam it’s produced to be then expanded in the turbine obtaining electrical power. Among the various substances present in nature, water has the best heat transfer properties, but in some cases due to its poor availability and importance as human resource and as agriculture support, it’s often preferable to use air as coolant; the use of air cooled condenser lead to different advantages as: the possibility to build the power plant in places without the presence of water, lower investment and maintenance costs and the possibility to not being subject to regulations that limit the exploitation of waterways. The scope of the air cooled condenser is to condense the steam flow coming from the steam turbine exhaust utilizing ambient air, in order to recycle the amount of the cycle water; then the condensate can be utilized to satisfy some final thermal users (for instance in co-generative plants) and/or be sent to the boiler in order to be re-evaporated and continue with the plant cycle process. During my stage at an engineering consultancy office for air cooled condenser in Switzerland, an important Italian society ask us to help them to find a possible concrete solution at their problems. Their waste to energy power plant, during steam turbine maintenance and in case of full rejection of the final thermal users, must to reject all the steam flow coming from the boiler into the atmosphere because their actual installed ACC can’t operate in pressure (the boiler generates a steam flow of 380 [ton/h] at 5 bar(a)). So, our scope is to project a new air cooled condenser that must work in addition and in parallel with the installed one, at working conditions of 5 bar(a) and that can operate under vacuum until 120mbar(a). To reach this aim, the only available choice is to utilize an ACC multi-rows which can withstand in pressure and under vacuum operating conditions. For the design of the ACC, I created an Excel tool that can estimate the needed heat transfer surface, the outlet air temperature, the needed volumetric air flow, the overall heat transfer coefficient of the tube bundles, the total fans electrical power consumption, and the other fundamental parameters, considering all the tubes characteristics (given to me by the company), design parameters and verifying all the design constraints. Once the air cooled condenser design has been defined, I analyse its operation under different working conditions and I created a control logic unit that can regulate the fans rotational speed needed to condensate the actual steam flow at that precise conditions. This control logic derives from the experiences I have gained in the field during inspective visits at different waste to energy plants placed in the north of Italy.
I condensatori raffreddati ad aria, usualmente indicati con l’acronimo ACC, sono i componenti più utilizzati negli impianti di produzione di potenza, dove il vapore prodotto viene espanso dalla turbina per generare energia elettrica. Tra le sostanze disponibili in natura, l’acqua possiede le migliori proprietà di scambio termico, ma a causa della sua non sempre facile reperibilità e per la sua importanza nel sostentamento dell’economia agricola e per usi umani, è spesso preferibile utilizzare l’aria come refrigerante. L’utilizzo di condensatori ad aria ha diversi vantaggi, tra essi: l’ubicazione della centrale in luoghi privi di risorse idriche naturali, il contenimento dei costi di investimento e manutenzione e il non essere soggetti a normative che limitano lo sfruttamento di corsi d’acqua. Lo scopo del condensatore è di condensare la portata di vapore proveniente dallo scarico della turbina mediante l’utilizzo di aria ambiente per poter recuperare la quantità di acqua precedentemente evaporata; una volta recuperato il condensato, esso può essere utilizzato per soddisfare la richiesta termica di alcune utenze (per esempio negli impianti cogenerativi) e/o può essere ri-inviato alla caldaia in modo da evaporarlo nuovamente e cosi continuare con il ciclo di funzionamento dell’impianto. Nel corso del mio stage presso un ufficio di consulenza ingegneristica riguardante i condensatori ad aria in Svizzera, una importante società italiana ha chiesto il nostro supporto per aiutarli a trovare una soluzione concreta ai loro problemi. Il loro termovalorizzatore, durante la manutenzione della turbina a vapore e nel caso di un completo rigetto da parte del teleriscaldamento, deve far sfiatare in atmosfera l’intera portata di vapore proveniente dalla caldaia poiché l’attuale ACC non può operare in pressione (la caldaia genera una portata di vapore pari a 380[ton/h] a 5 bar(a)). Quindi, il nostro obiettivo è quello di progettare un nuovo condensatore ad aria in grado di operare in aggiunta ed in parallelo all’esistente ACC sia in condizioni di 5 bar(a) sia in condizioni operative di vuoto spinto fino a 120 mbar(a). Per raggiungere questo obiettivo, l’unica scelta rimane quella di progettare un ACC a più file di tubi in grado di operare sia in pressione sia sottovuoto. Per la progettazione del nuovo ACC, ho creato un file Excel in grado di calcolare la superficie di scambio richiesta, la temperatura dell’aria in uscita, la portata volumetrica di aria, il coefficiente di scambio termico globale dei fasci tubieri, la potenza assorbita dai ventilatori e altri parametri fondamentali, considerando tutte le caratteristiche dei tubi di scambio (fornitemi dall’azienda), i parametri di progetto e verificando tutti i vincoli progettuali. Una volta definito il design del condensatore, ho analizzato il suo funzionamento in diverse condizioni operative e ho creato una logica di controllo in grado di regolare la velocità di rotazione dei ventilatori richiesta per condensare l’attuale portata di vapore alle relative condizioni operative. La logica di controllo è basata sull’esperienza che ho maturato durante le visite ispettive, effettuate in campo durante il periodo di stage, presso svariati termovalorizzatori presenti nel nord Italia.
Air cooled condenser: design and operating conditions
Rizzi, Edoardo
2022/2023
Abstract
Air cooled condensers, usually defined with the acronym ACCs, are the most widely used components in power production plants in which steam it’s produced to be then expanded in the turbine obtaining electrical power. Among the various substances present in nature, water has the best heat transfer properties, but in some cases due to its poor availability and importance as human resource and as agriculture support, it’s often preferable to use air as coolant; the use of air cooled condenser lead to different advantages as: the possibility to build the power plant in places without the presence of water, lower investment and maintenance costs and the possibility to not being subject to regulations that limit the exploitation of waterways. The scope of the air cooled condenser is to condense the steam flow coming from the steam turbine exhaust utilizing ambient air, in order to recycle the amount of the cycle water; then the condensate can be utilized to satisfy some final thermal users (for instance in co-generative plants) and/or be sent to the boiler in order to be re-evaporated and continue with the plant cycle process. During my stage at an engineering consultancy office for air cooled condenser in Switzerland, an important Italian society ask us to help them to find a possible concrete solution at their problems. Their waste to energy power plant, during steam turbine maintenance and in case of full rejection of the final thermal users, must to reject all the steam flow coming from the boiler into the atmosphere because their actual installed ACC can’t operate in pressure (the boiler generates a steam flow of 380 [ton/h] at 5 bar(a)). So, our scope is to project a new air cooled condenser that must work in addition and in parallel with the installed one, at working conditions of 5 bar(a) and that can operate under vacuum until 120mbar(a). To reach this aim, the only available choice is to utilize an ACC multi-rows which can withstand in pressure and under vacuum operating conditions. For the design of the ACC, I created an Excel tool that can estimate the needed heat transfer surface, the outlet air temperature, the needed volumetric air flow, the overall heat transfer coefficient of the tube bundles, the total fans electrical power consumption, and the other fundamental parameters, considering all the tubes characteristics (given to me by the company), design parameters and verifying all the design constraints. Once the air cooled condenser design has been defined, I analyse its operation under different working conditions and I created a control logic unit that can regulate the fans rotational speed needed to condensate the actual steam flow at that precise conditions. This control logic derives from the experiences I have gained in the field during inspective visits at different waste to energy plants placed in the north of Italy. Air cooled condensers, usually defined with the acronym ACCs, are the most widely used components in power production plants in which steam it’s produced to be then expanded in the turbine obtaining electrical power. Among the various substances present in nature, water has the best heat transfer properties, but in some cases due to its poor availability and importance as human resource and as agriculture support, it’s often preferable to use air as coolant; the use of air cooled condenser lead to different advantages as: the possibility to build the power plant in places without the presence of water, lower investment and maintenance costs and the possibility to not being subject to regulations that limit the exploitation of waterways. The scope of the air cooled condenser is to condense the steam flow coming from the steam turbine exhaust utilizing ambient air, in order to recycle the amount of the cycle water; then the condensate can be utilized to satisfy some final thermal users (for instance in co-generative plants) and/or be sent to the boiler in order to be re-evaporated and continue with the plant cycle process. During my stage at an engineering consultancy office for air cooled condenser in Switzerland, an important Italian society ask us to help them to find a possible concrete solution at their problems. Their waste to energy power plant, during steam turbine maintenance and in case of full rejection of the final thermal users, must to reject all the steam flow coming from the boiler into the atmosphere because their actual installed ACC can’t operate in pressure (the boiler generates a steam flow of 380 [ton/h] at 5 bar(a)). So, our scope is to project a new air cooled condenser that must work in addition and in parallel with the installed one, at working conditions of 5 bar(a) and that can operate under vacuum until 120mbar(a). To reach this aim, the only available choice is to utilize an ACC multi-rows which can withstand in pressure and under vacuum operating conditions. For the design of the ACC, I created an Excel tool that can estimate the needed heat transfer surface, the outlet air temperature, the needed volumetric air flow, the overall heat transfer coefficient of the tube bundles, the total fans electrical power consumption, and the other fundamental parameters, considering all the tubes characteristics (given to me by the company), design parameters and verifying all the design constraints. Once the air cooled condenser design has been defined, I analyse its operation under different working conditions and I created a control logic unit that can regulate the fans rotational speed needed to condensate the actual steam flow at that precise conditions. This control logic derives from the experiences I have gained in the field during inspective visits at different waste to energy plants placed in the north of Italy.| File | Dimensione | Formato | |
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2024_04_Rizzi_Tesi_01.pdf
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Descrizione: Tesi di Laurea Magistrale in ingegneria Energetica sui condensatori ad aria industriali
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4.07 MB
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2024_04_Rizzi_Executive Summary_02.pdf
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1.15 MB
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Adobe PDF
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1.15 MB | Adobe PDF | Visualizza/Apri |
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https://hdl.handle.net/10589/217412