Description du projet
Vers une application géothermique pleinement efficace
Les échangeurs de chaleur (HX) jouent un rôle crucial dans les centrales géothermiques. Toutefois, leur entretien est coûteux et ils restent vulnérables à la corrosion, en particulier dans le cas du cycle organique de Rankine (ORC). Or, les matériaux anticorrosifs de remplacement existants ont un impact négatif sur les performances des HX et nécessitent une augmentation de leur taille. Le projet GeoHex, financé par l’UE, soutiendra le développement de nouveaux matériaux destinés au secteur de la géothermie. Utilisant de l’acier au carbone à bas prix comme base, la surface du matériau sera modifiée et dotée d’un revêtement nanoporeux et sa face exposée à la solution saline sera couverte par un revêtement composite Ni-P/Ni-P-PTFE (par la méthode non-électrolytique). Ces revêtements conféreront aux HX des propriétés anti-incrustantes, anticorrosion et de transfert de chaleur optimisées qui amélioreront considérablement leurs performances, leur efficacité et leurs coûts dans les systèmes ORC.
Objectif
Heat exchangers (HXs) are the most critical components of a geothermal power plant specially for organic Rankine cycle (ORC) based plant and the capital cost of heat exchanger accounts for a large proportion of ORC, and even reaches about 86% when air cooled condenser is used. Direct heat exchangers (e.g. geothermal brine to district heating) and ORC HXs such as superheater, preheater, evaporator are in direct contact with the geothermal brine, causing scaling and corrosion at different extent based on the thermophysical condition and chemical composition of the geofluid. To handle corrosion, expensive materials are recommended, but due to lower thermal conductivity and degraded performance over time compel to increases the size of the HXs. Hence, improvements in the antiscaling and anticorrosion properties as well as heat transfer performance of the HX material will lead to smaller, more efficient and less costly systems.
GeoHex will rely on the use low cost carbon steel as base material for HX. Through modifying the surface with nano porous coating and controlling the surface chemistry (along with the surface structure), GeoHex will significantly improve the heat transfer performance of single phase and phase change heat transfer process respectively. To attribute the antiscaling and anticorrosion properties, the brine side of the surface will be Ni-P/Ni-P-PTFE duplex coated by electroless method.
GeoHex will significantly reduce the cost of ORC plant while lowering the environmental impact. The technology concept can be exploited to build cost efficient HXs for solar thermal energy, heat pumps, absorption chiller, geothermal energy-based district heating cooling system. GeoHex enabled ORC plant, heat pumps and absorption chiller can be used for waste heat recovery application. Hence, GeoHex will significantly contribute to enhance the energy security, decarbonise the economy, establish the EU leadership on renewables.
Champ scientifique
Mots‑clés
Programme(s)
Régime de financement
RIA - Research and Innovation actionCoordinateur
CB21 6AL Cambridge
Royaume-Uni