Cogeneration of Power Through Waste Heat Recovery Boilers and Economisers

1 Cogeneration of Power Through Waste Heat Recovery Boilers and Economisers 

Hot gas streams at 900-1000 °C are generated in sulphuric acid plants by bmning sulphur. These gases are cooled by waste heat recovery boiler before further processing. High-pressure steam at pressures of 45 kg/cm and temperatures of 410 °C is generated as a by-product which is supplied to a condensing turbine to produce power (which can be more than what is required to mn the plant). This surplus can be exported to other industries. 

Alternatively, this steam is used to mn a backpressure turbine coupled to the main air blower (which needs considerable power). The exhaust steam from the turbine can be used for process heating, e.g., evaporation of alum or phosphoric acid solutions or for obtaining potable water from sea water (in certain locations) by multiple-effect evaporators, thus saving heat energy required for such processes. This is cogeneration. 

---