Located at 500 mts from the beach in one of the Italian capitals of tourism, the SCM foundry in Rimini is one of the three plants involved in the demonstration activities of the REEMAIN project.
SCM is a large producer of cast-iron, with an yearly output of 20,000 tons from two production sites. “We have always been aware of environmental issues, even before these turned into legal constraints – says Stefano Cucchetti of SCM Research division – In the last years, the financial crisis and the growing costs of energy have made innovation a top priority for our company. Foundries run high energy consuming production processes and margins working on a low added value product tend to be tight. Innovating our manufacturing workflow is fundamental and this is why we have decided to team up with the REEMAIN consortium”.
As paradoxical as it may sound, in the foundry processes, energy is often used (or wasted) to expel energy (heat). This has become a challenge for the REEMAIN research team.
“Our emissions are strictly controlled – Stefano says – with the processes to melt metals, our furnaces reach temperatures of 1,600°. Then we need to expel smokes, but these have to transformed into carbonic dioxide with a methane burner and their temperatures lowered dramatically so that they do not damage our filters. Because of the extreme conditions developed in furnaces as a combination of high temperatures and corrosive dusts, we have very complex requirements, which we hope to solve partially through research in REEMAIN. Additionally, within a couple of years we expect to install methane powered furnaces. Thus we need to engineer a system that can work with today’s coal furnaces specifically designed for cast-iron, and tomorrow with the new technologies”.
Together with the challenges posed by the specificities of the cast-iron processes in terms of high temperatures, the recovery of thermal energy is also a priority.
“We look at doing it from the exhaust flows of the foundry, which means identifying the most appropriate solution to transfer energy from the flue gases to another instrumental medium (water, steam, organic fluids). This should result into the design of a new heat exchanger. The idea is to enable the transformation of the recovered thermal energy into electricity for internal use of the foundry or for "selling" to the network. The idea of producing electricity was proposed from the beginning having in mind an estimate of the waste heat from the furnace. Obviously, direct use of heat for internal needs was also kept in mind. Once we have a better idea of the heat exchanger, we expect to identify solutions that maximize the energy recovered from the exhaust flows (that is working at the highest possible temperature). This could be the result of a modular approach that suits the current conditions of the cupola furnace, but also future developments when the rotary furnaces will be installed. From a cost perspective, this might be the most delicate phase in our project, since the majority of the costs of the whole energy recovery solution will be due to the electricity generation system”.
In the first phase of the project SCM have been working together with the research teams in simulating the requirements and real conditions in which the exchanger would work.
“Right now – concludes Stefano – it is difficult to predict precisely what characteristics our prototype will have. For sure we expect substantial gains in efficiency for it”.