Operation and maintenance of a biomass fired – Organic Rankine Cycle – CHP plant: the experience of Cremona

Abstract

Thanks to various feed-in-tariff programs, aimed to the development of electric energy production from renewable sources, several biomass firing power plants have been realized in Italy in the last few years, contributing to the reduction of greenhouse gas emissions and fossil fuel energy dependence.In particular, during 2012 there was a rush for the completion of several renewable energy conversion power plants, leading up to 986 new plants to get the first connection to the grid (+81,3% with respect to 2011); among those, 80 new plants were solid biomass firing plants (+47,1% with respect to 2011) [1].Linea Energia S.p.A., the Energy Business Unit of the multiutility company LGH, Linea Group Holding, which operates over the areas of Brescia, Cremona, Crema, Lodi and Pavia, gave its contribution in 2012 with the realization and start-up of two waste wood fueled energy conversion plants located in the Northern Italy, more exactly in Cremona and Rodengo Saiano (Brescia).This paper focuses on the operation and maintenance experience of the waste wood conversion power plant of Cremona, which is capable for a gross electric power production of up to 1.0 MW and a thermal power recovery of up to 5.5 MW. In the first part of this paper a description of the plant is presented, giving an insight of the engineered process.In the second part, the performance analysis of the energy conversion process is discussed by comparing actual performance of the system with the originally defined reference performance.In 2016, as a consequence of the operation of the unit in anomalous conditions (air entering in the system) the turbine blades got scaled. The output of the turbine progressively decreased but was then successfully re-established after an extraordinary maintenance carried out by the turbine supplier.