COAL FIRED PLANTS

Coal is a fossil fuel. It is a major source of energy that is used to produce electricity for a large number commercial and residential users. The electricity is produced by what is called "Coal Fired" Power Plants. WorldCoal estimates that there are almost 900 billion tonnes of coal reserves in the world that could last for just under 120 years at current consumption/production rates. This does not mean that more does not exist because the estimation is for "proven" reserves only. In our lifetime we will never see a depletion of coal reserves.


     


Most countries have coal deposites but the biggest known reserves are in China, USA, India and Russia. Coal fired power plants normally have the coal transported to them by ships/barges, railroad or lorries. The coal has to be stockpiled in large enough quantities next to the power plant to ensure enough is available for continual operation of the plant. This coal is taken into the plant by automatic conveyer systems which feed it to machines which crush the coal into a fine powder which is literally "fired" or burned as an energy source for boilers which produce steam for steam turbines that work with a generator to produce electricity. The media presentation shows this in reasonable detail and helps us to appreciate the value of heat exchangers as well as  process engineering and design. Nowadays process engineers benefit from the use of 3D modeling and plant simulation software to make their life easier. The process can also be monitored and controlled by sensors and meter data which is fed back to a central control system situated somewhere in the plant. The data can also be relayed to other locations (some being remote) for further analysis.

Sometimes is it possible for systems engineers to overlook certain elements within a power plant because looking at the big picture might make them forget how previous power plants survived without all of the computers and control we have today. One of the greatest things about power plants is specialized control valves for fluids.  Control valves working under certain power plant conditions can easily be destroyed and cause operational problems because of high pressure drops which can cause something called cavitation if not properly checked. Cavitation can destroy everything including the valve plugs and seats and even it's body. Everything is  literally eaten away and proper control can be lost. There is a kind of science which involves the design of better control valves to either control cavitation or eliminate it. The following media presentation shows a brief demonstration of what it looks like in a laboratory. It is not the only great thing about power plants and of course we all must pay attention to pumps, turbine mechanisms, heat exchangers and control instrumentation. The example is used here simply because narrow minded engineers can get completely lost in computer systems forgetting that there are devices being used in the plant which also require an understanding of mechanical engineering, process engineering, instrumentation, chemical analysis, metallurgy and other important engineering disciplines.  To build, design, operate and maintain a power plant requires several engineering disciplines to work together.


     

Another interesting process is how the crushed coal is burned which is very intense process but these days we have access to presentations which can bring us inside a plant which the general public does not normally have access to. This one is amazing footage of the insides of a coal boiler