This Thesis summarizes the work that I carried out during my internship, at the technical office Bertolini, in Morbegno (So). I have been committed to analyze and partly develop a project for the construction of a new biomass-fired plant, based on the ORC (Organic Rankine Cycle) technology, for the supply of heat to an existing district heating network. Such a network serves the city of Morbegno and other municipalities nearby, and is currently fed by a cogeneration plant based on natural gas-fired Internal Combustion Engines (ICEs). The first part of the work was focused on determining the correct sizing of the power plant in connection with the existing and future heat demands. At the end, a plant with a combustion power of 6973 kW (on LHV basis) was designed, able of providing up to 4819 kW of thermal power to the district heating network, and 990 kW of electricity. Then, the functioning of the district heating network has been simulated both in the current and future configurations. In a reference thermal year, with the current configuration, 95,2%% of the heat supplied to the network is provided by the ICEs, 3% by an electric-driven heat pump coupled with the ICEs, and 1,8% by the integration boilers. Instead, in the future configuration, 58% of the heat supplied by a new biomass-fired plant, 40,8% by the ICEs, 0,8% by the electric-driven heat pump and 0,4% by the integration boilers. From the economic point of view, the investment features an IRR (Internal Rate of Return) of 22,77%, corresponding to a PBT (Pay Back Time) of 4,76 years. These economic performances are marginally lowered by accounting for the loss of profit due to the reduced heat generation from the existing cogeneration plant. However, still good figures are achieved, with an overall IRR of 17,91%, a PBT of 6,15. From the environmental standpoint, the analysis carried out showed that the in the future configuration one will imply an increase in the local emissions of NOx of 2,3 t/y, and 1,4 t/y an in the local Particulate Matter (PM) emissions. For the greenhouse gas emissions, the overall result is +/- 10.900 t/y for the heat production and 1.300 t/y for the electric energy.
Questa Tesi sintetizza il lavoro che ho svolto durante il tirocinio presso l’ufficio tecnico Bertolini, a Morbegno (So). Sono stato incaricato dell’analisi e del parziale sviluppo di un progetto per la costruzione di un nuovo impianto a biomassa, con tecnologia ORC (Organic Rankine Cycle), per la fornitura di calore a un’esistente rete di Teleriscaldamento (TLR). Tale rete serve la città di Morbegno e alcuni comuni limitrofi ed è attualmente alimentata da una centrale cogenerativa basata su Motori a Combustione Interna (MCI) a gas naturale. La prima parte del lavoro è stata incentrata sulla determinazione del dimensionamento ottimale del nuovo impianto, in connessione con la richiesta attuale e futura di calore. Alla fine, è stato progettato un impianto con potenza di combustione di 6973 kW (su base PCI), in grado di erogare 4819 kW termici al TLR e 990 kW elettrici. In seguito, il funzionamento della rete di TLR è stato simulato sia nella configurazione attuale, sia in quella futura. In un anno termico di riferimento, nella configurazione attuale, il 95,2% del calore fornito al TLR è prodotto dai MCI, il 3% da una pompa di calore elettrica accoppiata ai MCI e l’1,8% dalle caldaie di integrazione. Invece, nella configurazione futura il 58% sarà fornito dalla centrale a biomassa, il 40,8% dai MCI, lo 0,8% dalla pompa di calore e lo 0,4% dalle caldaie. Dal punto di vista economico, l’investimento presenta un TIR (Tasso Interno di Ritorno) del 22,77%, con un tempo di ritorno del capitale di 4,76 anni. Queste prestazioni economiche risultano ridotte prendendo in considerazione anche la perdita di profitto dovuta alla riduzione del calore prodotto dalla centrale cogenerativa esistente. Tuttavia, anche in questo caso di ottengono risultati positivi, con un TIR complessivo del 17,91% e un tempo di ritorno di 6,15. Dal punto di vista ambientale, l’analisi condotta mostra che si avrà un aumento nelle emissioni locali di NOx di 2,3 t/a e 1,4 t/a di particolato. Circa le emissioni di gas serra, che vengono valutate solo su scala globale, il risultato complessivo ammonta a 10.900 t/a per la produzione di calore e 1.300 t/a per la produzione di energia elettrica.
Analisi tecnico-economica di un sistema di cogenerazione alimentato a biomassa per teleriscaldamento
RONCONI, EMANUELE
2014/2015
Abstract
This Thesis summarizes the work that I carried out during my internship, at the technical office Bertolini, in Morbegno (So). I have been committed to analyze and partly develop a project for the construction of a new biomass-fired plant, based on the ORC (Organic Rankine Cycle) technology, for the supply of heat to an existing district heating network. Such a network serves the city of Morbegno and other municipalities nearby, and is currently fed by a cogeneration plant based on natural gas-fired Internal Combustion Engines (ICEs). The first part of the work was focused on determining the correct sizing of the power plant in connection with the existing and future heat demands. At the end, a plant with a combustion power of 6973 kW (on LHV basis) was designed, able of providing up to 4819 kW of thermal power to the district heating network, and 990 kW of electricity. Then, the functioning of the district heating network has been simulated both in the current and future configurations. In a reference thermal year, with the current configuration, 95,2%% of the heat supplied to the network is provided by the ICEs, 3% by an electric-driven heat pump coupled with the ICEs, and 1,8% by the integration boilers. Instead, in the future configuration, 58% of the heat supplied by a new biomass-fired plant, 40,8% by the ICEs, 0,8% by the electric-driven heat pump and 0,4% by the integration boilers. From the economic point of view, the investment features an IRR (Internal Rate of Return) of 22,77%, corresponding to a PBT (Pay Back Time) of 4,76 years. These economic performances are marginally lowered by accounting for the loss of profit due to the reduced heat generation from the existing cogeneration plant. However, still good figures are achieved, with an overall IRR of 17,91%, a PBT of 6,15. From the environmental standpoint, the analysis carried out showed that the in the future configuration one will imply an increase in the local emissions of NOx of 2,3 t/y, and 1,4 t/y an in the local Particulate Matter (PM) emissions. For the greenhouse gas emissions, the overall result is +/- 10.900 t/y for the heat production and 1.300 t/y for the electric energy.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/110222