A hogging ejector is a steam turbine ejector that evacuates air and creates a vacuum on a condenser. Their are vacuum ejectors that pull vacuum and help a thermal turbine unit work. A hogging ejector is a larger than normal ejector used when starting up and during heavy loads. Usually they are a steam operated venture type. Some plants use vacuum pumps and would use 2 pumps during hogging opeations and reduces to one when normal operation occurs. Hope it helps
Doug