Energy-intensive industries, such as steel industry are indispensable to Europe’s economy, as they supply several key value chains. The transformation of iron and steel industry from carbon dependent to CO₂-free, hydrogen steel production is embedded in environmental, technical and political frameworks influencing the realization of the decarbonization of the iron and steel industry.
New process streams occur by application of direct reduction plants (DRP) leading to high temperature condensate and high energy intake into gas washing water with temperatures up to 80 °C, leading to an increased cooling water demand to fulfill operational temperature requirements and legal discharge limits. Climate change is causing water stress to rise, which reduces water availability and increases salt contents. This, coupled with higher water temperatures, further escalates the demand for freshwater. Due to challenging water compositions, high temperatures, high corrosion and scaling, high salt contents and abrasive particles, no recovery of energy or water is practiced from such streams.
Background
About The Project
Therefore
To address these challenges, EnWaRec develops a holistic approach for cooling water circuits, consisting of heat, electricity and water recovery, energy and water reuse, and tailored water conditioning. Monitoring sensors measuring scaling and corrosion potential provide the base for tailored dosing of treatment chemicals, applicable up to 80 °C. Micro turbines recover the potential energy of water streams for sludge drying or operation of membrane distillation. Software tools determine the most suitable positions for installing heat exchangers and micro turbines to achieve maximum energy recovery.
Objectives and expected results
Aim of the project EnWaRec is the recovery of >50% of waste heat and 65% of hydropower from cooling circuits and their use for water recovery, steam production, sludge dewatering, drying or district heating. This contributes to the European Green Deal and the circular economy, focusing on reuse of energy, water and valuable materials as part of the transition to hydrogen-based steel production. Innovative approaches are unified in one holistic concept to ensure heat recovery and utilisation, reducing CO₂ emissions and saving resources such as natural gas. Water recovery secures supply for cooling and gas washing, partly decoupling production from freshwater demand. Suitable measurements and treatment chemicals ensure required water quality, while new coated materials minimise risks of scaling, corrosion and downtime.
Further on, the utilisation of the recovered energy or produced electricity for steam production using recovered water on one site and the enhanced sludge dewatering and drying on the other side for a metallurgical reuse of iron containing sludge, increase the environmental impact.
EnWaRec's
Specific objectives:
All objectives are clearly related to the objectives of the RFCS objective No. 10: “Conservation of resources, protection of the environment and circular economy”. EnWaRec has been aligned with the technological and time requirements of the European steel industry, in order to develop and demonstrate timely application-oriented results and technologies for a holistic approach to recover heat and hydropower from cooling circuits and its utilisation.
Holistic approach combining different technologies, sensors and tools for achieving goals regarding energy recovery and utilisation for decreasing CO₂ emissions including water recovery.
Suitable corrosion and scaling measurements for a tailored chemical dosing as mandatory step for an ensured heat and energy recovery including thermal stable treatment chemicals up to 80°C.
Coatings for corrosion and wear protection in micro turbines, heat exchangers and nozzles (cooling system).
Application of micro turbines in suitable water circuits with corrosive, abrasive or potentially scaling composition for production of electricity by recovery of hydropower for enhanced sludge treatment and operation of membrane distillation.
Heat exchanger with wear and scaling resistant surface for recovery of waste heat up to 80°C.
Utilisation of recovered waste heat for steam production with high temperature heat pumps and water recovery by membrane distillation producing a high-quality feed water for steam production – further waste heat utilisation: enhance sludge dewatering and drying.
Software tools, based on digital mapping and simulations to determine the:
• chemical dosing distribution and its impact to water characteristics,
• point for maximum heat outtake and most suitable positions for energy production by micro turbines.
Ambition
To achieve the described objectives, a holistic approach, combining the different technologies, measurements and tools is necessary. EnWaRec aims at solving the different challenges which are interconnected. For this, technologies and novel approaches as well as concepts added by fundamental research will be combined at technological, economic and environmental levels. In a structured overview related to the key innovation, it will be described how EnWaRec will go beyond the state of the art with the specific indications and the related ambitions.
