MIAC Energy/Assocarta Conference 2021 - ALAN CARNEVALI - RENOVIS

Описание: "Case history: two types of intervention for energy efficiency in paper mills". The full speech by Alan Carnevali of Renovis during the MIAC Energy/Assocarta Conference, which took place at MIAC 2021 exhibition held every year in October in Lucca (Italy). MIAC is the international paper industry event that sees the participation of 250 international exhibitors of the paper industry sector.

Two of the solutions proposed by Renovis Rational Energy Solutions, a UNI CEI 11352-certified ESCO that implements energy efficiency solutions, will be illustrated to the participating audience and it will be explained how the work carried out at the plant of a leading company in the tissue sector has enabled the company to get significant savings in natural gas by implementing the following solutions:

1. Heat recovery from turbogas. The energy efficiency project carried out by Renovis exploits the thermal energy recovered from the combustion fumes coming out of the GVR (Recovered Steam Generator) located in the vein of a 17MW gas turbine. Through the system, these fumes are conveyed through a heat exchanger that generates a thermal power of 5.5 MW entirely obtained from the described thermal waste. This power is used to produce water at 90°C for an insulated tank. The latter then generates a flow of hot water for heating the plant and for a second exchanger that preheats the make-up water for the GVR. The exhaust fumes are finally disposed of through a new chimney by means of a specially designed fan. The system is fully automated and thanks to the specially designed PLC is able to manage the hydraulic and aeraulic flows by means of pumps and fans driven by inverters and dampers managed by servomotors.

2. Air cooling to the co-pressor of a gas turbine: The average seasonal temperature of the site affects the average thermal efficiency of the plant’s combined cycle Turbogas co-generator. In summer with ambient temperatures between 30°C and 35°C, the turbine has an average nominal thermal efficiency of less than 32%. In these environmental conditions, cooling the air entering the compressor – by means of the heat exchanger made by Renovis – down to a temperature between 14°C and 17°C produces an increase in average thermal efficiency of 1.5%, close to nominal conditions. This increase in efficiency corresponds to an electrical power generated of between 1,000 kW and 1,500 kW. In order that the overall energy balance, including the energy used to cool the air, corresponds to a real economic benefit, it is obviously imperative that the necessary cooling energy is produced in the absence of electrical consumption. In the case of the application described here, part of the water at 90°C accumulated in the recirculation tanks is withdrawn from the heat recovery system mentioned in point 1.1 and sent to a LiBr absorption refrigeration unit specially sized to supply the cooling energy needed to cool the air entering the compressor to a constant temperature of 15°C.