Waste heat recovery and valorization to electricity and steam: Use of Heat2Power® tool in a real case study from the steel industry

Waste heat recovery (WHR) in steel shops and valorization (WHV) to electricity and steam can considerably cut off the environmental burden of the steelmaking process. However, WHR/WHV is a complex issue, as there are multiple, interrelated, parameters that needs quantifying at recovery and transfer levels. In this context, we developed and launched an optimization tool that is based on mixed-integer linear programming, commercially called Heat2Power®, to provide customized WHR/WHV solutions that strictly respect all the user's objectives. For instance, the user can define the waste heat streams availability over the examined time period, the waste heat valorization path (electricity or steam production or both) and selection of the thermodynamic cycle or turbine technology to be used (inputs). The Heat2Powe® tool can be used either as a customized process calculator calculating the economics and the volumetric footprint of the WHR/WHV unit (output 1), should the user define all the system parameters or as a process optimizer, should the user not be able to specify all the design parameters, leaving the optimizer to select the most efficient WHR/WHV technology for a given operating window (output 2). Comparing the Heat2Power® results with data retrieved from a real WHR/WHV case of the steel industry, it is found that a difference of less than 20 % is attained when identical operating conditions are considered, rendering Heat2Power® a trustful and valuable decision-making tool, especially for projects being at the design and development phase.