Introduction to Combine Cycle Power Plant

1. Introduction to CombineCycle Power Plant By Leelananda Pilanawithana

2. Power plants • Categorized by functional type • Base load • Peak load and emergency • Base load • Run continuously, stop only for maintenance. Generate power most in any given year. • Have lowest operating cost. • Its type • High efficient combined cycle plants fueled by natural gas or liquid fuel • Nuclear Power Plants • Conventional steam power plants fueled primarily by coal or fernours oil • Hydropower plants

3. Power plants • Peak load and emergency • Run during peak load demand period or an emergency. • Operating cost is high, but cheap to built. • Fast start and loading. • Type • Open Cycle (Simple cycle) gas turbine plant. • Diesel engine plants. • Hydropower plant

4. Definition • Combine • When several different things add together • Cycle • Process is repeated or moving around a circle. • In Thermodynamic point of view, • Rankine, • Diesel, • Otto , • Carnot, • Brayton, are some of the thermodynamic cycles.

5. Definition • Those cycles are always associated with one of the two type of combustion processes. • Internal Combustion • Gas Turbines, • Diesel engines, • Gasoline engines • External Combustion • Steam Engines (Boiler and steam turbine)

6. Cycle Definition • Combine Cycle • Employ more than one thermodynamic cycles. • Brayton cycle, • Rankine cycle. • Improve the simple Brayton cycle efficiency by capturing wasted energy in Brayton cycle and use it in Ranking Cycle. • Brayton cycle, • Engine used extensively is a Gas Turbine • utilize only a portion of the energy from the fuel that is being used Open cycle or • Reminder if not recovered is wasted. Simple cycle Open cycle Configuration Combinecycle Configuration

7. Cycle Definition • Rankine cycle • Engine used is Heat Recovery Boiler (HRSG) plus Steam Turbine. Basic equipment arrangement Temperature Entropy Diagram

10. Advantages of Combine Cycle Power Plant • Low installation cost / MW • High efficiency among all practical power cycles. • Low auxiliary power consumption/MW (2 – 3%) • Less manpower/MW ratio. • High reliability and availability. • Clean operating Condition. • Less Gestation period. • Fast starting characteristics. • Less water requirement.

11. Advantages of Combine Cycle Power Plant • Less pollution problems. • Flexibility in locating power plant. • Fuel flexibility. • Less space requirement. • Gas turbine can be operated as peak load plant and Steam turbine as base load plant by supplementary firing in HRSG unit

12. Disadvantages of Combine Cycle Power Plant • Need good quality fuel specifically low sulfur, vanadium and lead content . • Fuel treatment process is costly. • GT performance severely deteriorate with ambient temperature. • High Nox pollutant. • GT life is less due to corrosion problems. • Uneconomical partial load operation.