A rotary pre-heater comprising: an annular housing ; a hot-end connecting plate having a first inlet and a first outlet , the hot-end connecting plate being secured to a first axial end of the annular housing ; a cold-end connecting plate having a second inlet and a second outlet , the cold-end connecting plate being secured to a second axial end of the annular housing ; a rotor disposed for rotation in the annular housing and between the hot-end connecting plate and the cold-end connecting plate , the rotor comprising: a cold-end rotor mounted for rotation on a spindle proximate the cold-end connecting plate , the cold-end rotor having a first plurality of flow passages extending therethrough; a hot-end rotor assembly disposed on the cold-end rotor , the hot-end rotor assembly being proximate the hot-end connecting plate , the hot-end rotor assembly having a second plurality of flow passages extending therethrough; characterized by : an insulation assembly surrounding an exterior surface defined by an annular rim , the insulation assembly comprising a ceramic blanket engaging the exterior surface , and the insulation assembly comprising an insulation retaining assembly engaging the ceramic blanket , the insulation retaining assembly comprising: a plurality of retainer elements , each of the plurality of retainer elements comprising: a root end held in fixed relationship to the cold-end rotor ; a distal end proximate to and spaced apart from and in moveable relationship to the hot-end rotor ,portions of each of the plurality of retainer elements being adapted for circumferential movement. an annular housing ; a hot-end connecting plate having a first inlet and a first outlet , the hot-end connecting plate being secured to a first axial end of the annular housing ; a cold-end connecting plate having a second inlet and a second outlet , the cold-end connecting plate being secured to a second axial end of the annular housing ; a rotor disposed for rotation in the annular housing and between the hot-end connecting plate and the cold-end connecting plate , the rotor comprising: a cold-end rotor mounted for rotation on a spindle proximate the cold-end connecting plate , the cold-end rotor having a first plurality of flow passages extending therethrough; a hot-end rotor assembly disposed on the cold-end rotor , the hot-end rotor assembly being proximate the hot-end connecting plate , the hot-end rotor assembly having a second plurality of flow passages extending therethrough; a cold-end rotor mounted for rotation on a spindle proximate the cold-end connecting plate , the cold-end rotor having a first plurality of flow passages extending therethrough; a hot-end rotor assembly disposed on the cold-end rotor , the hot-end rotor assembly being proximate the hot-end connecting plate , the hot-end rotor assembly having a second plurality of flow passages extending therethrough; characterized by : an insulation assembly surrounding an exterior surface defined by an annular rim , the insulation assembly comprising a ceramic blanket engaging the exterior surface , and the insulation assembly comprising an insulation retaining assembly engaging the ceramic blanket , the insulation retaining assembly comprising: a plurality of retainer elements , each of the plurality of retainer elements comprising: a root end held in fixed relationship to the cold-end rotor ; a distal end proximate to and spaced apart from and in moveable relationship to the hot-end rotor ,portions of each of the plurality of retainer elements being adapted for circumferential movement. a root end held in fixed relationship to the cold-end rotor ; a distal end proximate to and spaced apart from and in moveable relationship to the hot-end rotor ,portions of each of the plurality of retainer elements being adapted for circumferential movement. <EOS>