The History of Steam
you look up steam on the internet, you get a host of links –
and most of these show old steam locomotives!! But steam is a lot
more than the old world engines of the industrial revolution.
Steam today is an integral and essential part of modern
technology. You cannot even begin to imagine the uses of steam in
our modern world.
- Steam facts – Believe
it or not
- Steam – here and now
What is steam?
- What is the difference
between water and steam?
- Steam at Work -
how is the heat in steam utilized?
- Why do
we use steam?
7 Geography of a process
11 Steam Table
two thousand years ago, Hero (actually Heron) of Alexandria
invented the first steam turbine, called the aeolipile, a hollow
sphere supported on two brackets on the lid of a basin of boiling
water. One bracket was hollow and conducted steam.
steam escaped from two bent pipes on the top, therefore creating
a force that made it spin around. The movement of the ball was
used to make puppets dance. Hero’s aeolipile illustrated
the scientific principle of Sir Isaac Newton’s third law of
motion which states that for every action there is an equal and
1660: Sir Isaac Newton proposes that a
jet of steam could be used to power a carriage, an idea now
considered to be a precursor to development of the jet
1698: Denis Papin develops the first piston that
is moved by the pressure of steam rather than atmospheric
1698: Thomas Savery patents "the Miner's
Friend," a machine that pumps water from coal mines. It
becomes the first practical machine powered by steam.
Thomas Newcomen, in collaboration with Thomas Savery, builds the
first practical steam engine to use a piston and cylinder,
bringing the steam engine out of the lab. It drives a pump in a
mine and produces about 5.5 horsepower.
inventor James Watt patents the new steam engine design with a
separate condenser. Watt's design used about 75% less fuel than a
similar Newcomen engine. His improvements to the steam engine
were fundamental to the changes wrought by the Industrial
Steam Engine in its most basic form showing the improvement of
the separate condenser not found on the Newcomen steam engine.
the steam engines developed, so did the boilers which produce
steam for them. The steam engines were first used for pumping
water, and then for running steamboats and steam
evolution of boilers.
facts – Believe it or not.
you know that one kg of water at 100°C and at atmospheric
pressure occupies 1/1,000ths of one cubic meter? When that kg of
water is converted to steam under the same condition, it occupies
1.66 cubic metres. That's almost 1600 times in volume. Can you
imagine that sudden release of energy?
Do you know that
jet fighters -- jet fighter aircraft on aircraft carriers -- are
launched by steam-powered catapults? Did you know that these jets
weigh approximately 30 tons when fully fueled and armed? Did you
know that when the catapult is released, the same jet travels
from zero kilometers per hour to 350 kilometers per hour in two
seconds? There is no medium which can generate that much thrust
other interesting uses of steam:
Steam is the force that
drives turbines for electricity in power plants. The fuel has
since changed from coal to Nuclear, but steam is still the motive
force that drives the turbines.
Water is dropped on forest
fires from aircrafts. It converts to steam and that is what
extinguishes the fire.
In explosive areas, steam-operated
fire extinguishers are used.
– here and now.
Steam is now used in a
number of areas. Food, paper, textile, chemical plants, power,
heating, transport..... all these industries use steam. In fact,
there are very few industries that don't use steam at all. And in
the industries that do use steam, usually one third of the total
energy bill is for steam generation!!
Hospital - for sterilisation
food in jackets by direct injection or jacket heating, for
example powder mix , jam , fruit-sauces, etc
- to sterilize the bottles
- cooking chocolate and to keep
chocolate soft for moulding
Dairy - making milk powder, cheese
places where steam is not used is the engineering industry,
forges...can anybody think of any other??
So, let us first
understand steam. What is it? How do we use it? Why is it better
than other forms of fluids for transporting heat?
Water exists in three forms. As a
solid, when we call it ice; as a liquid, when we call it water,
or as a gas when we call it steam. We will focus largely on the
liquid and gas phases, and on the change from one phase to the
Steam is an invisible gas generated by adding heat
energy to water in a boiler. Enough energy must be added to raise
the temperature of the water to the boiling pint. Then additional
energy - without any further increase in temperature - changes
the water to steam. This additional energy which is required to
make boiling water change to steam is called the heat of
vaporization or latent heat. This heat is not lost but stored in
the steam ready to be released to heat air, cook tomatoes, press
pants or dry a roll of paper. The quantity is different for every
pressure/ temperature combination, as shown in the steam tables.
is the difference between water and steam?
The condensation of steam is an exothermic process.
can attain higher temperatures with steam.
absorbs a lot of energy. Steam at 100°C is a lot hotter than
water at 100°C. This is because steam has a higher energy
holding capacity/ unit mass.
Steam is a very efficient and
easily controlled heat transfer medium. It is most often used for
transporting controlled energy from a central location (the
boiler) to any number of locations in the plant where it is used
to heat air, water or process applications. It both transports
energy and provides energy.
at Work – how is the heat of steam utilized?
flows from a higher temperature level to a lower temperature
level in a process known as heat transfer. Starting in the
combustion chamber of the boiler, heat flows through the boiler
tubes to the water. When the higher pressure in the boiler pushes
steam out, it heats the pipes of the distribution system. Heat
flows from the steam through the walls of the pipes into the
cooler surrounding air. This heat transfer changes some of the
steam back into water (condenses). That's why distribution lines
are usually insulated to minimize this wasteful and undesirable
When steam reaches the process areas like
jacketed vessels and heat exchangers in the system, the story is
different . Here the transfer of heat from the steam is
desirable. Heat flows to the air in an air heater, to the water
in a water heater or to food in a cooking kettle. Nothing should
interfere with this heat transfer.
do we use steam?
are many reasons why steam is one of the most widely used ways
for conveying (transporting) heat energy.
economical because the raw material is water. Water is
available freely and is relatively inexpensive. It is not toxic
and is environmentally safe.
It is efficient as
steam can hold five or six times as much potential energy as an
equivalent mass of water. Therefore, in its gaseous form, it is a
safe and efficient energy carrier.
Steam is an excellent
carrier of potential heat energy. If we pressurize steam,
it can carry higher temperatures. (Take a look at the steam
tables) At higher temperatures, more heat energy is contained so
its potential to do work is greater.
We find it is very
easy to pressurize steam. So, in most boilers steam is
generated at high pressures to give high steam temperatures.
technology is now so advanced, that boiler designs and
plant processes use almost all the energy carried by steam. In
fact, boilers are now using bagasse (sugarcane husk) and other
agri wastes as fuels, thus making the steam boiler a natural
choice for environmental reasons. Even "heat losses" in
blowdown and condensate are now being utilised in the
Steam is easy to distribute. Boilers
generate steam under pressure and steam flows naturally in
response to the pressure drop along the line.
steam has a high heat content, so small bore pipework is
required to distribute the steam at high pressure. The pressure
is then reduced at the point of use, if necessary. Therefore if
steam is used installation is easy and cheap. Its easier to
maintain. Therefore it is the preffered choice to convey heat
Steam is easy to control. As seen
earlier, there is a direct relationship between the pressure and
temperature of saturated steam, so its easy to see why
controlling steam is very easy. The amount of energy input to the
process is easy to control, simply by controlling the saturated
Modern controls are precise and
react very fast to changes of pressure or temperature. We use
Pressure Control Valves (PRVs) and Control Valves to control
pressure. Also, we use two-port valves on steam, whereas liquid
systems necessitate three-port valves. This reduces cost as
Heat transfer properties of steam are very
high. Steam evenly surrounds the product to be heated or can be
injected directly into the product being heated. It can fill any
space at a uniform temperature and will supply heat by condensing
at a constant temperature. Therefore the required heat transfer
area is relatively small; resulting in a compact, easy to install
and physically small plant.
Managing a modern steam
plant is easy. Everyone is trying to reduce costs and
increase the energy efficiency of steam operations. Now, more
than ever, industrial energy users are looking to maximise energy
efficiency and minimise production costs and overheads. Your per
unit production costs can mean the difference between survival
and failure in the marketplace. Some plants even hook-up their
steam system to modern networked instrumentation and control
systems to allow centralised control. If the user wishes, the
components of the steam system can also operate independently
A modern boiler house
personnel starting from the boiler in-charge up, are made aware
of costs. Planned maintenance and systematic checks aid quality
and drastically cut downtime. Any leaks or blockages are
automatically pinpointed and immediately brought to the attention
of the utilities engineer. With proper maintenance schedules,
plants can last for many years (One of the oldest boilers
seen by Vikram was an old Babcock & Wilcox water-tube boiler
at Wimco, the match lites factory in Ambarnath. It is a 105 years
old, and still working!)
In addition to this, when a steam
system requires maintenance, the relevant part of the system is
easy to isolate and can drain rapidly, meaning that
repairs may be carried out quickly. Even if your steam plant is
old, it is far cheaper to bring it up to date than replace it
with an alternate method of energy distribution system.
is sterile, and thus widely used in hospitals and in the
food, pharmaceutical and health industries. It is also used for
Steam is safe - it cannot
cause sparks and presents no fire risk. It is therefore ideal for
use in hazardous areas or explosive atmospheres. Steam is also
used in fire-extinguishing systems.
Steamline helps make these products