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In this note, we are going to learn about Steam Turbine Cogeneration System, and also about its block diagram, working principle, and applications as well. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.

Author Name: Arun Paul.

Table of Contents

What is Steam Turbine Cogeneration System?

Steam Turbine Cogeneration is the process of using steam turbines to create both electricity and useable thermal energy (heat) from a single fuel source. This combined heat and power (CHP) system is extremely efficient, transforming a significant amount of the fuel energy into useful work and heat, minimizing waste and increasing total energy efficiency.

Block Diagram of Steam Turbine Cogeneration System

Below we listed each and every section of the Steam Turbine Cogeneration System –

Fuel Supply: The system starts with the fuel source (natural gas, coal, or biomass).
Combustion Chamber: The fuel is burned in the combustion chamber, generating heat.
Steam Boiler: The steam boiler uses heat from the combustion chamber to turn water into high-pressure steam.

Steam Turbine: The high-pressure steam from the boiler powers the steam turbine, which converts the steam’s thermal energy into mechanical energy.
Electric Generator: The mechanical energy from the turbine powers the electric generator, which produces electricity.
Power Output: The electricity generated is either fed into the electric grid or used locally.

Condenser: The turbine’s exhaust steam passes through a condenser, which cools and condenses it into water.
Pump: The condensed water (condensate) is then pumped back into the boiler and reused, completing the cycle.
Heat Recovery System: In addition to condensing steam, the system recovers valuable thermal energy from exhaust steam. This energy can be utilized to heat buildings, generate hot water, or provide process heat.

Steam Turbine Cogeneration Working

This system working principle is listed below –

Fuel Combustion: Fuel (natural gas, coal, biomass, etc.) is burned in a boiler to generate high-pressure steam.
Steam Turbine: The high-pressure steam is fed into a steam turbine. As the steam moves through the turbine, it rotates the turbine blades, transforming thermal energy into mechanical energy.

Electric Generator: The turbine is coupled to an electric generator, which transforms mechanical energy to electricity.
Heat Recovery: After going through the turbine, the low-pressure steam retains significant thermal energy. This steam is either condensed to make hot water or utilized directly to heat something.

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Types of Steam Turbine

There are two types of Steam Turbine –

Back Pressure Turbines: These turbines produce high-pressure steam that can be used for heating or industrial processes. They are commonly used when a large volume of steam is required for process heat.

Condensing Turbines: These turbines produce low-pressure steam that is condensed into water. This type is commonly employed when the primary purpose is to create electricity, with less emphasis on heat recovery.

Advantages of STCS

Here are some advantages of Steam Turbine Cogeneration System –

Cogeneration systems can achieve 70-90% efficiency, compared to 30-50% for standard power plants that exclusively produce electricity.
Cogeneration minimizes fuel costs by producing both electricity and heat, making it a more cost-effective energy source.

Higher efficiency requires less fuel, resulting in lower greenhouse gas and other pollutant emissions.
Cogeneration systems can operate independently of the grid, providing a consistent source of electricity and heat.

Applications of STCS

These are the applications of this cogeneration system –

Factories, refineries, and chemical facilities frequently demand both energy and process heat, making cogeneration an excellent alternative.

Cogeneration can be used in urban settings to provide energy and heat to residential and commercial buildings.
These institutions frequently have a steady demand for both energy and heat, making cogeneration an effective option.
Cogeneration can provide energy for lights and heat for climate control.