Back Pressure Turbines (BPT)

Back pressure turbines are often used in industrial plants and they can be single stage or multistage. It serves as a reducing station between the boiler and the process steam header.

These fall under straight back pressure turbines which can be used when back pressure steam is fully utilized to meet process demands. Here, the resulting power generation is incidental to the process steam demand. In order to feed the steam demands at medium, intermediate pressures, the back pressure turbine uses bleed points (uncontrolled extractions) when the bleed steam volume demand is low and pressure variations can be tolerated. This makes them ‘bleed cum back pressure turbines’. Sometimes, the high volume demand along with intolerable pressure variations calls for the use of an extraction steam to meet the process steam demand at intermediate pressure. This is done using back pressure turbines with one controlled extraction point and are called extraction cum back pressure turbines.

APPLICATION

They are primarily for power generation where bleed steam is required for feed water heating (HP heater, LP heater and Deaerator requirement) and/or where bleed steam is utilized to meet small process demands.