BoilersPRESENTED BY:ADITYA PATKIFARHAN SIDDIQUISAYALI PANGARE

What is a boiler? A water containing vessel in which water is heated under

pressure Transfer heat from a fuel source (oil, gas, coal) into steam The steam or hot fluid circulates out of the boiler for use in

various process eg: Generation of power through turbines and Chemical industry, Pharmaceutical industry, Manufacturing plant.

Boiler Equipment

Components of Boiler Equipment:

Furnace: where air and fuel are combines to produce combustion gases.

Tank: The tank contains liquid which is heated upto the evaporating temperature by the combustion gases.

Steam Drum: The steam drum contains the generated water vapour.

Superheater: If superheated steam is required the stem from the steam drum is passed through the superheater tubes,which are exposed to combustion gases.

Economizer: The feedwater is cold as compared to the saturated water inside the tank so economier heats it to some extent so that fuel and time wastage is reduced.

Chimney: It is the duct that leads boiler exhausts to outside atmosphere.

Types Of Boilers There are different types of boilers according to: 1) Axis 2)Type Of Furnace 3) Circulation 4) Use

But Basically there are two types:

Fire Tube Boilers Water Tube Boilers

Fire-Tube Boilers

Advantages:• Compact in const.• Fluctuations of steam

demand can be met easily.• Cheap.

Disadvantages:• Time consuming.• It cant achieve higher

steam pressure.

Water-Tube Boilers Advantages:• Larger heating surfaces

can be achieved by increasing no. of tubes.

• Heat transfer rate is high.• Efficiency is more.

Disadvantages:• Large in size.• Costly.

Feedwater control:

Feedwater control is the regulation of water to the boiler drum.Proper boiler operation requires that the level of water in the steam

drum should be maintained within certain band. If the level becomes too low, the boiler can run dry resulting in mechanical damage of drum and boiler piping.If the level becomes too high,water can be carried over into steam pipework possibly damging downstream equipments.It is important to make sure that the water level in the boiler drum must be above 50% all the time.

Types Of Feedwater Control 1) Single element 2) Two element 3) Three element

Three-element: Similar to feed flow, changes in

steam flow can also cause large deviations in drum level.

Here, steam flow rate is measured and used as the set point of the feedwater flow controller thus feedwater flow rate is adjusted to match the steam flow.

To ensure better control, the output of the drum level controller is added to the feedforward from steam flow.

The combination of drum level measurement, steam flow measurement, and feed flow measurement is called three-element control.

Conclusion:The boiler is a complicated and continuous process in any process industry. We have partially studied implementation of various loops and we will try to monitor and control various parameters using cascade control scheme.