A steam engine uses a hydrocarbon based fuel source. The combustion of the fuel releases the chemical energy in the bonds in the form of thermal energy.
That is called boiling. And it is something you can see and observe, but it is something tht is chemically relted and so it is a chemical change.
Steam turbines are external combustion engines.
If you use saturated steam, the main source of the heat is provided by the condensation of the steam at a constant temperature. The energy provided by the condensing steam is significantly more than what you can get from just changing the temperature of superheated steam. When the temperature remains constant, design calculations are also a lot easier; the temperatures stay the same (or almost the same) for the steam along the entire run and the pressure stays the same (or almost the same).
The main benefit derived from burning anything is the energy that is released (normally as heat). In power generation, the energy is used to boil water which will generate steam in order to turn steam turbines to generate electricity. Coal is one of the most abundant 'fuels' on earth, therefore the fuel is very cheap, and can easily be burned to generate energy.
In the steam drum, where steam exits and flows to the superheaters.
Heat And Kinetic Energy
Coal is a chemical compound which contains chemical energy. To convert coal into mechanical energy, you use it (burn it) to produce heat and use the heat to boil water, the steam from which will drive a steam engine which delivers mechanical energy.
A steam engine would be one example, a motor car engine would be another.
An engine is needed to do this. A steam engine A jet engine A car engine A battery driven electric engine. The process is normally multi step.
heat engine: steam, internal combustion, turbines, etc
steam engine uses thermal energy to convert water into steam and then uses pressure of steam to move the engine .thus thermal energy into pressure and further pressure into mechanical energy.
You have aids!
it is a chemical change
Chemical change changes the electrons of matter, a physical change does not. Water is water as ice, water and steam, this is a change of state but physically there is no change of water it is a change of the energy content of water.
Steam from a kettle is a physical change.
chemical
A steam engine. Like used in a steam locomotive