Boiler pressure parts

In a steam generator the parts through which the feed water and steam flows where the pressure of the system,is much higher than atmospheric pressure, are generally termed as boiler pressure parts.

Parts of boiler which generally come under the category of boiler pressure parts are:

Economiser

Boiler drum

Water walls

Super heater

re-heater

Economizer is a heat exchanger which exchanges heat between water ( which is fed in to the boiler ) & the flue gas.

Flue gases are byproducts of combustion which are classically vented through long pipes known as flues.Flue gas is the gaseous product of combustion of a fuel.

It means it increases the temperature of the feed water using the otherwise wasted heat of the flue gas.

Types:1.steaming economiser 2.non-steaming economiser.

Advantages:1.Reduced size of boiler. 2.Reduction in fuel consumption.

Combustion:any process in which a substance reacts with oxygen to produce a significant rise in temperature and the emission of light.

Thermal Power Plant

A superheater is a device used to convert saturated steam or wet steam into dry steam.

Types1.A radiant superheater is placed directly in the combustion chamber.2.A convection superheater is located in the path of the hot gases.3.A separately fired superheater, as its name implies, is totally separated from the boiler.

Use:The superheater increases the capacity of the plant.Eliminates corrosion of the steam turbine.Reduces steam consumption of the steam turbine.

Dry steam:steam that does not contain droplets of water.

Wet steam:steam that contains water droplets in suspension.

Saturated steam:steam at the temperature of the boiling point which corresponds to its pressure.

Lead to - produce

Boiler drum:A boiler drum is a unit which is rated at a certain temperature and pressure to force the boiler feedwater into the vapor phase (steam).

Boiler drum use :Purpose of the boiler drum is to collect steam from all the various tubes in a boiler, and send it to the turbine to spin the generator.

Rate: To determine the limits of safe functioning for a machine or electrical device.

Unit:an individual thing

Blow down:Removal of a portion of water from the boiler drum is known as blow down.

Boiler blowdown is water intentionally wasted from a boiler to avoid concentration of impurities during continuing evaporation of steam.

water wall:A waterwall in a boiler is any furnace wall that is comprised of refractory and tubes in a water-tube boiler.

They serve a two fold purpose here in that they capture heat that would otherwise escape to the atmosphere and help heat the water in the boiler. And they also help keep the refractory cool (relatively speaking) This prevents spalling of the refractory.

A refractory material is one that retains its strength at high temperatures.

Reheater:A device using highly superheated steam or high-temperature flue gases as a medium serving to restore superheat to partly expanded steam; used often between high - and low-pressure turbines.

Desuperheater:A device that reduces the temperature of superheated steam, and recovers useful heat in the process

Desuperheaters remove the superheat in the steam that is to be used for auxiliary purposes, the reason is that if high temperature steam was used for auxiliaries then the materials used would have to be capable of withstanding high temperatures, this leads to increased initial cost.