Prospective environmental and techno-economic assessment of steam production by means of heat pipes in the steel industry

Many high-temperature processes in the steel industry discharge waste heat directly into the atmosphere without recovery of the dissipated energy. Additionally, the industry has been compelled to reduce its fossil energy consumption through increasing reductions in carbon emission caps. Accordingly, the development of new technologies, or new uses of the existing ones, for the exploitation of waste heat is of considerable importance. This study analysed the feasibility of using heat pipe technology for a novel use; the generation of steam by taking advantage of the energy contained in combustion fumes from reheating furnaces. To the best of our knowledge, the present study is the first to explore the technical viability of this technology under laboratory conditions, reaching efficiencies between 39.7% and 62.7%. The laboratory results were extrapolated to the conditions of a real steel plant, and it was estimated that 65% of its steam needs could be covered using heat pipes, leading to substantial savings in steam purchase and carbon taxes that ensure the economic viability of this technology. The environmental viability was confirmed through a comparative life cycle analysis. Notable reductions in environmental impacts were achieved, including a 97% reduction in CO2 emissions.