The　ethanol　(EtOH)　dehydration　process　using　ionic　liquids　(ILs)　as　entrainers　by　extractive　distillation　integrated　with　a　heat　pump　was　systematically　investigated　from　the　molecular　level　to　the　process　scale.　[BMIM][Cl]　was　selected　as　the　appropriate　entrainer　from　a　variety　of　[Cl]-based　ILs　by　achieving　vapor-liquid　equilibrium　(VLE)　experiments　for　binary　systems　of　EtOH-IL　and　water　(H2O)-IL.　The　VLE　behavior　of　a　ternary　EtOH-H2O-IL　system　demonstrates　that　the　azeotropic　phenomenon　of　the　binary　EtOH-H2O　system　is　effectively　broken　in　the　presence　of　IL.　Moreover,　the　UNIFAC　model　was　successfully　extended　to　predict　the　VLE　of　the　EtOH-H2O-IL　system.　The　microscopic　mechanism　of　the　EtOH-H2O　separation　with　[BMIM][Cl]　as　an　entrainer　at　the　molecular　level　was　identified　by　performing　molecular　dynamics　simulations.　It　is　found　that　hydrogen　bond　interactions　of　EtOH/H2O-[BMIM]+　and-[Cl]-　play　crucial　roles　in　breaking　the　azeotropic　phenomenon.　The　equilibrium　stage　model　for　the　ethanol　dehydration　process　with　[BMIM][Cl]　as　an　entrainer　was　established,　wherein　the　binary　group　interaction　parameters　of　the　UNIFAC　model　were　embedded.　The　process　simulation　and　optimization　were　performed　at　the　industrial　scale.　The　extractive　distillation　process　intensified　with　the　heat　pump　technology　has　better　economic　and　environmental　efficiencies　when　compared　with　the　conventional　one.　The　total　annual　cost　and　CO2　emission　of　the　former　are　reduced　by　27.01　and　80.46%,　respectively,　compared　with　those　of　the　latter.　In　short,　the　process　intensification　technology　for　ethanol　dehydration　by　using　ILs　as　entrainers　integrated　with　the　heat　pump　proposed　in　this　work　is　in　line　with　sustainable　chemical　separation　processes,　which　can　be　directly　extended　to　other　extractive　distillation　processes　with　ILs.　©　2021　American　Chemical　Society.