Many industries, such as textile, dairy and rice, need steam for their processes. The steam is produced in boilers at high pressures (10-25 bars) but stepped down by a throttle valve to deliver low-pressure steam (2-8 bars) at the points of use.
In the process, a lot of potential energy in the high-pressure steam is lost. Professor Satya Seshadri and PhD student Vipin Venugopal, of the Energy and Emission Research Group at IIT Madras, have invented an ‘expander’ system to produce electricity with the high-pressure steam. The expander replaces the throttle, but performs the same function of reducing the pressure.
However, in the expander the steam pushes a rotor connected to a generator, producing electricity. Seshadri tells Quantum that steam from a 1 tph boiler can give 20-35 kW of power. The cost of the system can be paid back in 18 months because of the power generated.
The expander is an improvement over the conventional ‘energy conservation turbines’ because it can handle large variations in steam pressure and is also not affected by water droplets in the steam.
Seshadri believes that 15 GW of capacity can be created in process industries with the expander.