Model and Optimize a Supercritical Power Plant

Khaled Sallam, Oklahoma State University-Main Campus, Mechanical and Aerospace Engineering

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Summary

A typical gas-fired steam powerplant utilizes a superheater, a reheater, and multiple feedwater heaters to improve the thermal efficiency. In this design project you are required to consider an ideal steam power plant with a steam generator (boiler), a turbine, a condenser and a pump. The required power output is 512 MW, maximum temperature allowed in the cycle is 1000 F, condenser temperature is 25 C. Please optimize the plant performance by changing the boiler pressure. Can the design improve by adding a reheater stage and/or an open feedwater heater. The design constraints include the maximum boiler pressure and the minimum value for the steam quality at the turbine exit.


Learning Goals

1) The students learn that engineering design involves a compromise between conflicting requirement. The assignment also improve their comprehension of thermodynamics by giving them a computational playground to try extreme operating conditions

2) MATLAB is essential to conduct multiple design iteration using loops. The steam property function (XSteam) is essential for the calculations.

3) Synthesis if ideas: The students will realize that there is room for new design (i.e. reheating) to solve the conflict between the need to increase the boiler pressure and the need to increase the quality of the steam at the turbine exit.

4) The students start to learn that in design problems they have to supply some of the parameters based on field experience and literature unlike in homework problems where all the required quantities are given. They will gain knowledge about actual operating conditions for power plants.

Context for Use

1) This is design project is for junior students as part of the course Thermal Fluid Design. The class size is 60 students. The institution is Oklahoma State University.
2) This is a short take-home project. The students are given 2 weeks to write the code to model the thermodynamic cycle and optimize the performance to improve the efficiency.
3) The principles of thermodynamics (1st law and steam properties) are mastered before this assignment.
4) It is very easy to adapt this activity in any thermofluid course (basic knowledge of 1st law is required).
5) MATLAB skills: Loop (change the pressure), functions (call XSteam), plotting (plot several variables on the same graph).

Description and Teaching Materials


Simulate an Ideal Supercritical Powerplant (HTML File 11kB Sep16 21)


Teaching Notes and Tips

The students should be invited to improve the cycle performance by adding and optimizing a reheat stage to improve the steam quality at the turbine exit.

Assessment

Students should find the optimum boiler pressure and the reheat pressure that maximize the the plant efficiency while still observe the design constraints.

References and Resources

https://www4.eere.energy.gov/manufacturing/tech_deployment/amo_steam_tool/overview