Steam Locomotive

Posted by PITHOCRATES - November 13th, 2013

Technology 101

The Steam Locomotive was one of the Few Technologies that wasn’t replaced by a Superior Technology 

Man first used stone tools about two and a half million years ago.  We first controlled fire for our use about a million years ago.  We first domesticated animals and began farming a little over 10,000 years ago.  The Egyptians were moving goods by boats some 5,000 years ago.  The Greeks and Romans first used the water wheel for power about 2,500 years ago. The Industrial Revolution began about 250 years ago.  James Watt improved the steam engine about 230 years ago.  England introduced the first steam locomotive into rail service about 210 years ago. 

In the first half of the 1800s the United States started building its railroads.  Helping the North to win the Civil War.  And completing the transcontinental railroad in 1869.  By 1890 there were about 130,000 miles of track crisscrossing the United States.  With the stream locomotives growing faster.  And more powerful.  These massive marvels of engineering helped the United States to become the number one economic power in the world.  As her vast resources and manufacturing centers were all connected by rail.  These powerful steam locomotives raced people across the continent.  And pulled ever longer—and heavier—freight trains.

We built bigger and bigger steam locomotives.  That had the power to pull freight across mountains.  To race across the Great Plains.  And into our cities.  With the chugging sound and the mournful steam whistle filling many a childhood memories.  But by the end of World War II the era of steam was over.  After little more than a century.  Barely a blip in the historical record.  Yet it advanced mankind in that century like few other technological advances.   Transforming the Industrial Revolution into the Second Industrial Revolution.  Or the Technological Revolution.  That gave us the steel that built America.  Electric Power.  Mass production.  And the production line.  None of which would have happened without the steam locomotive.  It was one of the few technologies that wasn’t replaced by a superior technology.  For the steam locomotive was more powerful than the diesel-electric that replaced it.  But the diesel-electric was far more cost-efficient than the steam locomotive. Even if you had to lash up 5 diesels to do the job of one steam locomotive.

The Hot Gases from the Firebox pass through the Boiler Tubes to Boil Water into Steam

The steam engine is an external combustion engine.  Unlike the internal combustion engine the burning of fuel did not move a piston.  Instead burning fuel produced steam.  And the expansion energy in steam moved the piston.  The steam locomotive is a large but compact boiler on wheels.  At one end is a firebox that typically burned wood, coal or oil.  At the other end is the smokebox.  Where the hot gases from the firebox ultimately vent out into the atmosphere through the smokestack.  In between the firebox and the smokebox are a bundle of long pipes.  Boiler tubes.  The longer the locomotive the longer the boiler tubes. 

To start a fire the fireman lights something to burn with a torch and places it on the grating in the firebox.  As this burns he may place some pieces of wood on it to build the fire bigger.  Once the fire is strong he will start shoveling in coal.  Slowly but surely the fire grows hotter.  The hot gases pass through the boiler tubes and into the smokebox.  And up the smoke stack.  Water surrounds the boiler tubes.  The hot gases in the boiler tubes heat the water around the tubes.  Boiling it into steam.  Slowly but surely the amount of water boiled into steam grows.  Increasing the steam pressure in the boiler.  At the top of the boiler over the boiler tubes is a steam dome.  A high point in the boiler where steam under pressure collects looking for a way out of the boiler.  Turned up into the steam dome is a pipe that runs down and splits into two.  Running to the valve chest above each steam cylinder.  Where the steam pushes a piston back and forth.  Which connects to the drive wheels via a connecting rod.

When the engineer moves the throttle level it operates a variable valve in the steam dome.  The more he opens this valve the more steam flows out of the boiler and into the valve chests.  And the greater the speed.  The valve in the valve chest moved back and forth.  When it moved to one side it opened a port into the piston cylinder behind the piston to push it one way.  Then the valve moved the other way.  Opening a port on the other side of the piston cylinder to allow steam to flow in front of the piston.  To push it back the other way.  As the steam expanded in the cylinder to push the piston the spent steam exhausted into the smoke stack and up into the atmosphere.  Creating a draft that helped pull the hot gases from the firebox through the boiler tubes, into the smokebox and out the smoke stack.  Creating the chugging sound from our childhood memories.

The Challenger and the Big Boy were the Superstars of Steam Locomotives

To keep the locomotive moving required two things.  A continuous supply of fuel and water.  Stored in the tender trailing the locomotive.  The fireman shoveled coal from the tender into the firebox.  What space the coal wasn’t occupying in the tender was filled with water.  The only limit on speed and power was the size of the boiler.  The bigger the firebox the hotter the fire.  And the hungrier it was for fuel.  The bigger locomotives required a mechanized coal feeder into the firebox as a person couldn’t shovel the coal fast enough.  Also, the bigger the engine the greater the weight.  The greater the weight the greater the wear and tear on the rail.  Like trucks on the highway railroads had a limit of weight per axel.  So as the engines got bigger the more wheels there were ahead of the drive wheels and trailing the drive wheels.  For example, the Hudson 4-6-4 had two axels (with four wheels) ahead of the drive wheels.  Three axles (with 6 wheels) connected to the pistons that powered the train.  And two axels (with four wheels) trailing the drive wheels to help support the weight of the firebox.

To achieve ever higher speeds and power over grades required ever larger boilers.  For higher speeds used a lot of steam.  Requiring a huge firebox to keep boiling water into steam to maintain those higher speeds.  But greater lengths and heavier boilers required more wheels.  And more wheels did not turn well in curves.  Leading to more wear and tear on the rails.  Enter the 4-6-6-4 Challenger.  The pinnacle of steam locomotive design.  To accommodate this behemoth on curves the designers reintroduced the articulating locomotive.  They split up the 12 drive wheels of the then most powerful locomotive in service into two sets of 6.  Each with their own set of pistons.  While the long boiler was a solid piece the frame underneath wasn’t.  It had a pivot point.  The first set of drive wheels and the four wheels in front of them were in front of this pivot.  And the second set of drive wheels and the trailing 4 wheels that carried the weight of the massive boiler on the Challenger were behind this pivot.  So instead of having one 4-6-6-4 struggling through curves there was one 4-6 trailing one 6-4.  Allowing it to negotiate curves easier and at greater speeds.

The Challenger was fast.  And powerful.  It could handle just about any track in America.  Except that over the Wasatch Range between Green River, Wyoming and Ogden, Utah.  Here even the Challenger couldn’t negotiate those grades on its own.  These trains required double-heading.  Two Challengers with two crews (unlike lashing up diesels today where one crew operates multiple units from one cab).  And helper locomotives.  This took a lot of time.  And cost a lot of money.  So to negotiate these steep grades Union Pacific built the 4-8-8-4 articulated Big Boy.  Basically the Challenger on steroids.  The Big Boy could pull anything anywhere.  The Challenger and the Big Boy were the superstars of steam locomotives.  But these massive boilers on wheels required an enormous amount of maintenance.  Which is why they lasted but 20 years in service.  Replaced by tiny little diesel-electric locomotives.  That revolutionized railroading.  Because they were so less costly to maintain and operate.  Even if you had to use 7 of them to do what one Big Boy could do.

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Electricity, Heat Engine, Superheated Dry Steam, Coal-Fired Power Plant, Geothermal Power Plant and Waste-to-Energy Plant

Posted by PITHOCRATES - November 7th, 2012

Technology 101

(Originally published August 1, 2012)

Geothermal Power Plants and Waste-to-Energy Plants each produce less than Half of 1% of our Electricity

We produce the majority of our electricity with heat engines.  Where we boil water into steam to spin a turbine.  Or use the expanding gases of combustion to spin a turbine.  The primary heat engines we use are coal-fired power plants, natural gas-power plants and nuclear power plants.  The next big source of electricity generation is hydroelectric.  A renewable energy source.  In 2011 it produced less than 8% of our electricity.  These sources combined produce in excess of 95% of all electricity.  While renewable energy sources (other than hydroelectric) make up a very small percentage of the total.  Wind power comes in under 3%.  And solar comes in at less than 0.2% of the total.  So we are a very long way from abandoning coal, natural gas and nuclear power.

Two other renewable energy sources appear to hold promise.  Two heat engines.  One powered by geothermal energy in the earth.  The other by burning our garbage.  In a waste-to-energy plant.  These appear attractive.  Geothermal power appears to be as clean as it gets.  For this heat isn’t man-made.  It’s planet-made.  And it’s just there for the taking.  But the taking of it gets a little complicated.  As is burning our trash.  Not to mention the fact that few people want trash incinerators in their neighborhoods.  For these reasons they each provide a very small percentage of the total electric power we produce.  Both coming in at less than half of 1%.

So why steam?  Why is it that we make so much of our electrical power by boiling water?  Because of the different states of matter.  Matter can be a solid, liquid or a gas.  And generally passes from one state to another in that order.  Although there are exceptions.  Such as dry ice that skips the liquid phase.  It sublimates from a solid directly into a gas.  And goes from a gas to a solid by deposition.  Water, though, follows the general rule.  Ice melts into water at 32 degrees Fahrenheit (or 0 degrees Celsius).  Or water freezes into ice at the same temperature.  Water vaporizes into steam at 212 degrees Fahrenheit (or 100 degrees Celsius).  Or steam condenses into water at the same temperature.  These changes in the state of matter are easy to produce.  At temperatures that we can easily attain.  Water is readily available to vaporize into steam.  It’s safe and easy to handle.  Making it the liquid of choice in a heat engine.

Today’s Coal-Fired Power Plant pulverizes Coal into a Dust and Blows it into the Firebox

A given amount of water will increase about 1600 times in volume when converted to steam.  It’s this expansion that we put to work.  It’s what pushed pistons in steam engines.  It’s what drove steam locomotives.  And it’s what spins the turbines in our power plants.  The plumes of steam you see is not steam, though.  What you see is water droplets in the steam.  Steam itself is an invisible gas.  And the hotter and drier (no water) it is the better.  For water droplets in steam will pit and wear the blades on a steam turbine.  Which is why the firebox of a coal-fired plant reaches temperatures up to 3,000 degrees Fahrenheit (about 1,650 degrees Celsius).  To superheat the steam.  And to use this heat elsewhere in the power plant such as preheating water entering the boiler.  So it takes less energy to vaporize it.

To get a fire that hot isn’t easy.  And you don’t get it by shoveling coal into the fire box.  Today’s coal-fired power plant pulverizes coal into a dust and blows it into the firebox.  Because small particles can burn easier and more completely than large chunks of coal.  As one fan blows in fuel another blows in air.  To help the fire burn hot.  The better and finer the fuel the better it burns.  The better the fuel burns the hotter the fire.  And the drier the steam it makes.  Which can spin a turbine with a minimum of wear.

In a geothermal power plant we pipe steam out of the ground to spin a turbine.  If it’s hot enough.  Unfortunately, there aren’t a lot of geothermal wells that produce superheated dry steam.  Which limits how many of these plants we can build.  And the steam that the planet produces is not as clean as what man produces.  Steam out of the earth can contain a lot of contaminants.  Requiring additional equipment to process these contaminants out.  We can use cooler geothermal wells that produce wet steam but they require additional equipment to remove the water from the steam.  The earth may produce heat reliably but not water.  When we pipe this steam away the wells can run dry.  So these plants require condensers to condense the used steam back into water so we can pump it back to the well.  A typical plant may have several wells piped to a common plant.  Requiring a lot of piping both for steam and condensate.  You put all this together and a geothermal plant is an expensive plant.  And it is a plant that we can build in few places.  Which explains why geothermal power makes less than half of 1% of our electricity.

We generate approximately 87% of our Electricity from Coal, Natural Gas and Nuclear Power

So these are some the problems with geothermal.  Burning trash has even more problems.  The biggest problem is that trash is a terrible fuel.  We pulverize coal into a dust and blow into the firebox.  This allows a hot and uniform fire.  Trash on the other hand contains wet mattresses, wet bags of grass, car batteries, newspapers and everything else you’ve ever thrown away.  And if you ever lit a campfire or a BBQ you know some things burn better than other things.  And wet things just don’t burn at all.  So some of this fuel entering the furnace can act like throwing water on a hot fire.  Which makes it difficult to maintain a hot and uniform fire.  They load fuel on a long, sloping grate that enters the furnace.  Mechanical agitators shake the trash down this grate slowly.  As the trash approaches the fire it heats up and dries out as much as possible before entering the fire.  Still the fire burns unevenly.  They try to keep the temperature above 1,000 degrees Fahrenheit (about 538 degrees Celsius) .  But they’re not always successful.

They can improve the quality of the fuel by processing it first.  Tearing open bags with machinery so people can hand pick through the trash.  They will remove things that won’t burn.  Then send what will burn to a shredder.  Chopping it up into smaller pieces.  This can help make for a more uniform burn.  But it adds a lot of cost.  So these plants tend to be expensive.  And nowhere as efficient as a coal-fired power plant (or nuclear power plant) in boiling water into superheated dry steam.  Also, raw trash tends to stink.  And no one really knows what’s in it when it burns.  Making people nervous about what comes out of their smoke stacks.  You add all of these things up and you see why less than half of 1% of our electricity comes from burning our trash.

This is why we generate approximately 87% of our electricity from coal, natural gas and nuclear power.  Coal and nuclear power can make some of the hottest and driest steam.  But making a hot fire or bringing a nuclear reactor on line takes time.  A lot of time.  So we use these as baseload power plants.  They generate the supply that meets the minimum demand.  Power that we use at all times.  Day or night.  Winter or summer.  They run 24/7 all year long.  Natural gas plants add to the baseload.  And handle peak demands over the baseload.  Because they don’t boil water they can come on line very quickly to pickup spikes in electrical demand.  Hydroelectric power shares this attribute, too.  As long as there is enough water in the reservoir to bring another generator on line.  The other 5% (wind, solar, geothermal, trash incinerators, etc.) is more of a novelty than serious power generation.

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Electricity, Heat Engine, Superheated Dry Steam, Coal-Fired Power Plant, Geothermal Power Plant and Waste-to-Energy Plant

Posted by PITHOCRATES - August 1st, 2012

Technology 101

Geothermal Power Plants and Waste-to-Energy Plants each produce less than Half of 1% of our Electricity

We produce the majority of our electricity with heat engines.  Where we boil water into steam to spin a turbine.  Or use the expanding gases of combustion to spin a turbine.  The primary heat engines we use are coal-fired power plants, natural gas-power plants and nuclear power plants.  The next big source of electricity generation is hydroelectric.  A renewable energy source.  In 2011 it produced less than 8% of our electricity.  These sources combined produce in excess of 95% of all electricity.  While renewable energy sources (other than hydroelectric) make up a very small percentage of the total.  Wind power comes in under 3%.  And solar comes in at less than 0.2% of the total.  So we are a very long way from abandoning coal, natural gas and nuclear power.

Two other renewable energy sources appear to hold promise.  Two heat engines.  One powered by geothermal energy in the earth.  The other by burning our garbage.  In a waste-to-energy plant.  These appear attractive.  Geothermal power appears to be as clean as it gets.  For this heat isn’t man-made.  It’s planet-made.  And it’s just there for the taking.  But the taking of it gets a little complicated.  As is burning our trash.  Not to mention the fact that few people want trash incinerators in their neighborhoods.  For these reasons they each provide a very small percentage of the total electric power we produce.  Both coming in at less than half of 1%.

So why steam?  Why is it that we make so much of our electrical power by boiling water?  Because of the different states of matter.  Matter can be a solid, liquid or a gas.  And generally passes from one state to another in that order.  Although there are exceptions.  Such as dry ice that skips the liquid phase.  It sublimates from a solid directly into a gas.  And goes from a gas to a solid by deposition.  Water, though, follows the general rule.  Ice melts into water at 32 degrees Fahrenheit (or 0 degrees Celsius).  Or water freezes into ice at the same temperature.  Water vaporizes into steam at 212 degrees Fahrenheit (or 100 degrees Celsius).  Or steam condenses into water at the same temperature.  These changes in the state of matter are easy to produce.  At temperatures that we can easily attain.  Water is readily available to vaporize into steam.  It’s safe and easy to handle.  Making it the liquid of choice in a heat engine.

Today’s Coal-Fired Power Plant pulverizes Coal into a Dust and Blows it into the Firebox

A given amount of water will increase about 1600 times in volume when converted to steam.  It’s this expansion that we put to work.  It’s what pushed pistons in steam engines.  It’s what drove steam locomotives.  And it’s what spins the turbines in our power plants.  The plumes of steam you see is not steam, though.  What you see is water droplets in the steam.  Steam itself is an invisible gas.  And the hotter and drier (no water) it is the better.  For water droplets in steam will pit and wear the blades on a steam turbine.  Which is why the firebox of a coal-fired plant reaches temperatures up to 3,000 degrees Fahrenheit (about 1,650 degrees Celsius).  To superheat the steam.  And to use this heat elsewhere in the power plant such as preheating water entering the boiler.  So it takes less energy to vaporize it.

To get a fire that hot isn’t easy.  And you don’t get it by shoveling coal into the fire box.  Today’s coal-fired power plant pulverizes coal into a dust and blows it into the firebox.  Because small particles can burn easier and more completely than large chunks of coal.  As one fan blows in fuel another blows in air.  To help the fire burn hot.  The better and finer the fuel the better it burns.  The better the fuel burns the hotter the fire.  And the drier the steam it makes.  Which can spin a turbine with a minimum of wear.

In a geothermal power plant we pipe steam out of the ground to spin a turbine.  If it’s hot enough.  Unfortunately, there aren’t a lot of geothermal wells that produce superheated dry steam.  Which limits how many of these plants we can build.  And the steam that the planet produces is not as clean as what man produces.  Steam out of the earth can contain a lot of contaminants.  Requiring additional equipment to process these contaminants out.  We can use cooler geothermal wells that produce wet steam but they require additional equipment to remove the water from the steam.  The earth may produce heat reliably but not water.  When we pipe this steam away the wells can run dry.  So these plants require condensers to condense the used steam back into water so we can pump it back to the well.  A typical plant may have several wells piped to a common plant.  Requiring a lot of piping both for steam and condensate.  You put all this together and a geothermal plant is an expensive plant.  And it is a plant that we can build in few places.  Which explains why geothermal power makes less than half of 1% of our electricity.

We generate approximately 87% of our Electricity from Coal, Natural Gas and Nuclear Power

So these are some the problems with geothermal.  Burning trash has even more problems.  The biggest problem is that trash is a terrible fuel.  We pulverize coal into a dust and blow into the firebox.  This allows a hot and uniform fire.  Trash on the other hand contains wet mattresses, wet bags of grass, car batteries, newspapers and everything else you’ve ever thrown away.  And if you ever lit a campfire or a BBQ you know some things burn better than other things.  And wet things just don’t burn at all.  So some of this fuel entering the furnace can act like throwing water on a hot fire.  Which makes it difficult to maintain a hot and uniform fire.  They load fuel on a long, sloping grate that enters the furnace.  Mechanical agitators shake the trash down this grate slowly.  As the trash approaches the fire it heats up and dries out as much as possible before entering the fire.  Still the fire burns unevenly.  They try to keep the temperature above 1,000 degrees Fahrenheit (about 538 degrees Celsius) .  But they’re not always successful.

They can improve the quality of the fuel by processing it first.  Tearing open bags with machinery so people can hand pick through the trash.  They will remove things that won’t burn.  Then send what will burn to a shredder.  Chopping it up into smaller pieces.  This can help make for a more uniform burn.  But it adds a lot of cost.  So these plants tend to be expensive.  And nowhere as efficient as a coal-fired power plant (or nuclear power plant) in boiling water into superheated dry steam.  Also, raw trash tends to stink.  And no one really knows what’s in it when it burns.  Making people nervous about what comes out of their smoke stacks.  You add all of these things up and you see why less than half of 1% of our electricity comes from burning our trash.

This is why we generate approximately 87% of our electricity from coal, natural gas and nuclear power.  Coal and nuclear power can make some of the hottest and driest steam.  But making a hot fire or bringing a nuclear reactor on line takes time.  A lot of time.  So we use these as baseload power plants.  They generate the supply that meets the minimum demand.  Power that we use at all times.  Day or night.  Winter or summer.  They run 24/7 all year long.  Natural gas plants add to the baseload.  And handle peak demands over the baseload.  Because they don’t boil water they can come on line very quickly to pickup spikes in electrical demand.  Hydroelectric power shares this attribute, too.  As long as there is enough water in the reservoir to bring another generator on line.  The other 5% (wind, solar, geothermal, trash incinerators, etc.) is more of a novelty than serious power generation.

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