Two examples of applying BPSTs to recover emissions free electricity from steam process loops are presented below:

BPST Pressure Reducing Valve Replacement

Many industrial facilities produce steam at a pressure higher than that demanded by process requirements. Steam passes through pressure-reducing valves (PRVs, also known as letdown valves) at various locations in the steam distribution system to let down or reduce its pressure. A BPST can perform the same pressure-reducing function as a PRV while converting steam energy into electrical energy. In a backpressure steam turbogenerator, shaft power is produced when a nozzle directs jets of high-pressure steam against the blades of the turbine’s rotor. The rotor is attached to a shaft that is coupled to an electrical generator. The steam turbine does not consume steam. It simply reduces the pressure of the steam that is subsequently exhausted into the process header. However, this means the exhaust steam has a lower temperature than it would have had if its pressure had been reduced through a PRV. This heat loss typically requires an increase in boiler steam throughput to maintain the same steam energy input for process heating needs.

BPST Bottoming Cycle to CHP Plant

Modern gas turbine-based CHP systems (doesn’t have to be limited to campus/district energy systems) can increase their power output by integrating a BPST in combined cycle configuration. When recovering steam through a heat recovery steam generator (HRSG), from gas turbine exhaust in a CHP system, there is a balance between steam capacity and steam pressure (related to temperature). Often the steam pressure exiting the HRSG is higher than required by the process or heating . Instead of adding a pressure reducing station, a BPST generator can be economically added to increase the electric output of the CHP plant.