From coal to electricity the old fashion way.

Walking along the Lisbon Tagus river waterfront I passed this building complex.

My first impression was "brewery", woo hoo!

Breweries, however, don't require this many boilers.

It is, in fact, the old Tejo Power Station (which powered Lisbon for 3 decades).  Now it's the terrific Lisbon Electrical Museum. The brickwork is very well done (Portuguese industrial style, with art nouveau mixed in), but it's just decorative.  The real building is steel underneath.

The Portuguese have done a magnificent job of preserving and displaying a page from energy history. The original power plant in 1909 only served 1,521 customers. In order to appreciate why the place is built the way it is you have to first grasp the concept of the Carnot Engine. 

Sadi Carnot - French physicist. Like Einstein, Carnot did a lot of his work at an early age. 
By Louis-Léopold Boilly - http://www-history.mcs.st-and.ac.uk/history/PictDisplay/Carnot_Sadi.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=577483

Carnot, at age 27, published this book in 1824:

Reflections on Cooking Fish on Your  Motor or Other  Surly Machines.

Correct translation

"Reflections on the Motive Power of Fire" is one of those definitive books in the history of man ("The Origin of Species" by Charles Darwin is more widely known by the general public). The book firmly entrenched Carnot in the history of physics as "The Father of Thermodynamics". In essence, what Carnot figured out is that there is a theoretical limit to the amount of "work" that you can get done by an engine. The "work"  in the case of the electrical plant is the generation of electricity. 

The "fall of heat" from a high temperature to a lower temperature is where the work comes from.

It really is that simple (more or less). The higher the temperature vs. your cooling source - the more work you can accomplish.

The original power plant was built in 1909.  None of those buildings exist anymore. The only reason I mention it is that they were designed by Fernand Touzet (of whom you've never heard). His boss is much more famous - Gustave Eiffel.

The whole process began down at the docks:

This crane looks handy for unloading a ship, unfortunately it didn't get as much use as it could have. 

Unloading the coal ships was mostly done hand.  Brutal, dangerous work for which they had no lack of eager workers. The ship would pull into port and the town would blow a special whistle indicating work was available. You had to be at least 17 for the privilege of unloading a coal ship using a basket balanced on your head. The older workers manned the crane. The coal was dumped into carts and moved (again by hand) along tracks to be dumped into the crusher.

Moving coal wearing a long sleeve white shirt?

Looking down at the crusher

The crusher, as the name suggests, made sure the coal was of a uniform size. The composition of the coal varied quite a bit depending upon where it was quarried.  Coal imported from Great Britain had 3 times the caloric value of Portuguese coal. To compensate for the differences, after crushing, the coal was hoisted up and spread to 3 different mixing bins.

Bucket from crusher

crusher and first hoist

First hoist (on left) dumps into blending/mixing bins. From there the coal is hoisted again for distribution to the boilers.

During WWII the mixing bins held more that just coal. They were forced to burn any fuel they could find - sawdust, coke, olive pomace, almond and pine nut shells, eucalyptus, dust bunnies, nazi leaflets, voting ballots not cast for Salazar, etc.

After blending the fuel to whatever caloric value they wanted, the stuff was then dumped down the big vertical chute into the furnace (boiler).  These boilers went into operation in 1941.  They're about 100 feet tall. 

It's at this point where the quality of the museum really begins to shine. I've always wondered exactly how coal is fed into a boiler. Turns out its done by conveyor belt. A conveyor belt made out of really thick metal chunks.  You can see the belt through the open doors on the left (its coming from the back of the boiler and making the turn upwards). If the boiler was running you would never open those doors without wearing a fire suit and using a long pole. 

BTW, Babcock and Wilcox is a 150 year old company still in business in Charlotte, North Carolina.

This is looking directly into the boiler's fire bed. Burning coal would be sitting on the conveyor belt.

This is the conveyor belt up close.  It's made with large, thick, plates of steel all stacked together. It had to be made this robust or the burning coal would have just melted it. From an engineering standpoint, the belt movement is all predicated on the long bar forming the hinge not breaking. If it did break you'd have to wait at least a week for the boiler to cool down enough so that you could enter the furnace and start beating on it with a sledgehammer.

The fire box containing all that super hot coal is made out of ceramic bricks.

One of the boilers has been cut away such that you actually get to walk right through the firebox (which made my hair stand on end. I walked in, snapped some quick shots and got the hell out as fast as I could).  This is looking down on (fake, thank God) burning coal (1,200 Celsius).

To really get the coal burning faster and hotter - air was blown right into the fire box. This is the intake duct.

This is the blower itself

(Looking straight down at the rear of the boiler) At the back of the fire box the conveyor belt turns under itself, dumping out the coal ash.

What happens next to the ash is quite scary.

These guys were standing directly underneath the boiler above them, unloading hot ashes. This staged scene doesn't do the actual job justice.  The heat would be off the charts, the air choked with ash. In those days safety equipment didn't exist. This is one of the worst jobs I've ever seen. A very difficult, never ending task in an extremely hostile environment. 

Does a hat count as safety gear?

The narrow gauge tracks were added in later years in an attempt to lighten the load of the poor guys working here, but the process was never automated.

I'm surprised he has any hair left.  The floor above him contains coal burning at 2,200 degrees F.

So what happens to all the heat the boilers produce? The boilers you see are the high pressure boilers (the low pressure ones were removed in the 1920's). 

The name of the game is to recover as much of the heat from the hot gasses as possible. Remember the basic principle of the Carnot engine - the hotter the better at this point in the cycle. That's why these boilers are called high pressure boilers - they not only convert the water to steam, they heat the steam up to 850 degrees.

The water is heated in pipes. This way you can contain the pressure of the steam without blowing the boiler to bits. Click here to see what happens to uncontained steam from an ordinary house waterheater  https://www.youtube.com/watch?v=9bU-I2ZiML0 (courtesy of the lads from Mythbusters)

These pipes get blasted by the hot coal gasses

They start out using water that has been pre-heated

More cold water entering the bottom part of the boiler

In a low pressure boiler you convert the water to steam and use it right away.  In a high pressure boiler the steam is continuously recirculated above the hot burning coal until it reaches 850 degrees.  At this point the steam is extraordinarily dangerous. A tiny crack in a pipe or fitting will leak steam out with enough force to instantly chop a person in half.

The destination for all this steam is here:

This is a multi-stage steam turbine built in 1934.

AEG is not an American household name, but it's as well known in Europe as GE is in the US.

The 540 PSI steam is injected into the big turbine starting at this end (note the small size of the turbine blades at the outer edge of the wheel). The turbine is where thermal energy (steam) gets converted to mechanical energy (spinning of the shaft).

At the opposite end of the turbine are the big blades.  They harvest power from the steam which is now much lower pressure (having passed through the high pressure vanes on the other end)

This chute is the return pathway for the now much lower pressure steam after it's passed through the turbine.  Looking at the size of the  massive casting of steel will give you a clue as to how much power still remains in the steam.

A modern steam turbine looks much the same. The neat thing about steam turbines is that they couldn't care less where the steam comes from (geothermal, nuclear, natural gas boilers,   Bob's House-O-Steam, etc.)

The turbine turns a big shaft at 3,000 rpm connected to:

this big bad boy generator (mechanical energy converted to electrical energy). Output is 10,500 volts. All the generators combined produced about 60 megawatts.

To put 60 megawatts in perspective, the output from just one big fan doohickie below is 8 megawatts:

One single revolution from an 8 megawatt wind generator will power an average house for a full day.

Industrial sized brushes that are picking up the power generated by the spinning of the rotor.

One inherent problem of using water to run a power plant is the water itself. You need a lot of very pure water to get the process to work.  If you used river water in the system it would work just fine - for about an hour. River water has way too many dissolved minerals, dirt, fish, etc.  In short order the pipes would all be clogged with scale. To get around this problem the plant generates distilled water and then continuously reuses it (losing about 5% each cycle to leaks).  The steam, after passing through the turbine, is sent over to the condenser facility. Staying in its pipes, the steam comes in contact with the cold water from the Tagus river through a heat exchanger:

It takes an enormous amount of water from the river to cool down the steam:

River cooling intake pipes

Opened pump housing for the raw water intake

I worked hard to image-enhance the internal pump vanes.  A pool pump works exactly the same way.  This pump can move 18,000 gallons per minute.

 So why bother to condense the steam back to water? 

Carnot's model says that it's the difference between the hot side and the cold side of the engine that determines the power available.

In an odd twist of fate - the factors that brought the power plant into existence also took it back out.  In the early days of the Tejo power plant it wasn't essential to the every day life of Lisbon. Lisbon didn't use much electricity before WWII. Even though Portugal was neutral during the war, they had great difficulty getting raw materials - such as gas (which is what most households used for power back then). While they didn't have much gas, they did have coal (even though it was low quality).  By changing habits away from gas towards electricity Lisbon could continue to grow. The war, however, showed the Portuguese graphically the dangers of reliance upon outside power sources. In 1944 they passed a law mandating hydroelectric power as their main source of electricity.

This is the Castelo de Bode dam that now supplies a good deal of Lisbon's needs

Lots of rivers to choose from.  Portugal has 57 hydroelectric dams.

Thus, by 1968 the Tejo power plant had been relegated to back-up, peak needs, reserve power only usage.  By 1975 it was shut down completely.  And there it sat (at least it wasn't belching soot and ash all over Lisbon anymore).  An eyesore until 2006 when it re-emerged as a museum. Today the old Tejo power plant is one of the most visited museums in all of Portugal. 

I've greatly simplified the operation of the plant for two reasons. One, this blog is long enough already. Two, I sortuv forgot what each of the pictures I took were about. Power plants, even old ones, aren't simple. The following are neat pictures of,     of,    of, - stuff.

Condenser tubes. Your call as to where exactly this fits into the equation.

Old style bucket-type turbine.

Really neat gears.

No idea what it's turning.  Probably another pump.

No clue (looks like another pump), cool green though. Looks important.

These are controls for the boiler - note the shafts headed upwards

Shafts continuing their way upwards.

This magnificent piston steam engine supplied electrical power to just the power plant itself. This "little" generator could be brought to life fairly simply - powering all the electrical pumps needed to bring the main system on-line.

Innards of the above steam engine.

Generator for the little steam engine.  Note the big flywheel (brass colored) with the grooves on the side.  To start the engine you had to first make sure all the pistons were lined up so that when you opened the steam valve the engine ran in the correct direction. You did that by sticking a big steel pry bar into a slot and manhandling the engine a few degrees of rotation at a time.

The starting pry bar in question.

More cool green stuff

One of the issues with coal powered electrical generation (besides the mess and pollution) is manpower.  It took 520 people to generate a measly 60 megawatts:

So if you find yourself in Lisbon, take a couple hours to walk around the power plant. Oh yeah, there's a buncha art crap on display as well.