Definition of Boiler

A boiler is a pressure vessel with a shape and size designed to produce steam. Steam with a certain pressure is then used to deliver heat to a process.

Working Principle

The working principle of the boiler (Saturated steam) can be seen in the figure below.

Feed water after going through the pretreatment process in the softener or condensate water is pumped to the economizer.

In the economizer preheating occurs which utilises the exhaust heat in the chimney. Preheating is intended to increase the efficiency of the boiler.
Furthermore, feed water enters the boiler but previously given chemichal according to the specified dose.
After that, the feed water that is heated in the boiler changes phase to steam and is ready to be distributed.
After the steam changes phase back to water (condensate water) it can be pumped back into the boiler again. Make up water is only used to replace the loss of water due to the blowdown process.

Boiler System

Feedwater System

Feed water is water that is supplied to the boiler to be converted into steam. While the feed water system is an automatic water supply system for boilers according to steam needs. There are two sources of feedwater, namely:
Condensate: steam that has changed phase to water (condenses)
Make up water: raw water that has been treated

To improve the efficiency of the boiler the feed water before being supplied to the boiler is preheated using waste heat from the chimney.

Steam System

The steam system is the process of controlling steam production in the boiler, such as: capacity, pressure, etc. Furthermore, steam is distributed to users through piping lines.

Fuel System

The fuel system is all the equipment or appliances used to provide boiler fuel. The equipment used depends on the type of fuel the boiler uses.

Boiler Classification

Berbagai bentuk boiler telah berkembang mengikuti kemajuan teknologi dan evaluasi dari produk-produk boiler sebelumnya yang dipengaruhi oleh gas buang boiler yang mempengaruhi lingkungan dan produk steamseperti apa yang akan dihasilkan. Berikut klasifikasi boiler yang telah dikembangkan:

A. Based on pipe type:

Fire Tube:

The fire pipe boiler type has characteristics: produces low steam capacity and pressure.

How it works: the ignition process occurs in the pipe, then the heat generated is delivered directly into the boiler containing water. The size and construction of the boiler affects the capacity and pressure produced by the boiler.

Water Tube:

The water pipe boiler type has the characteristics: it produces high steam capacity and pressure.

How it works: the ignition process occurs outside the pipe, then the heat generated heats the pipe containing water and previously the water is conditioned first through the economizer, then the steam produced is first collected in a steam-drum. Until the pressure and temperature are appropriate, through the secondary superheater and primary superheater stages the new steam is released into the main distribution pipe. In the water pipe, the flowing water must be conditioned against minerals or other content dissolved in the water. This is the main factor that must be considered for this type.

B. Based on the fuel used:

Solid Fuel

Solid fuel boilers have the following characteristics: the price of combustion raw materials is relatively cheaper than boilers that use liquid fuels and electricity. The efficiency value of this type is better when compared to electric type boilers.
How it works: heating that occurs due to combustion between the mixing of solid fuel (coal, baggase, rejected product, municipal waste, wood) with oxygen and heat source.

Oil Fuel

The liquid fuel boiler type has the following characteristics: the most expensive combustion raw material price compared to all types. The efficiency value of this type is better when compared to solid fuel boilers and electricity.

How it works: heating that occurs due to combustion between mixing liquid fuel (diesel, IDO, residue, kerosene) with oxygen and heat source.

Gaseous Fuel

The gas-fired boiler type has the following characteristics: the lowest price of combustion raw materials compared to all boiler types. The efficiency value of this type is better when compared to all types of boilers based on fuel.

How it works: combustion that occurs due to the mixing of fuel gas (LNG) with oxygen and heat source.

Electric

The electric boiler type has the characteristics: the price of heating raw materials is relatively cheaper than the boiler using liquid fuel. The efficiency value of this type is the lowest when compared to all types of boilers based on fuel.

How it works: heating that occurs due to an electric source that supplies a heat source.

C. Based on the usefulness of the boiler:

Power Boiler

This type of power boiler has characteristics: its main use is to produce steam as a power plant, and the remaining steam is used to run industrial processes.

How it works: the steam produced by this boiler uses a water tube boiler type, the resulting steam has a large pressure and capacity, so it is able to rotate the steam turbine and generate electricity from the generator.

Industrial Boiler

The industrial boiler type has characteristics: its main use is as a producer of steam or hot water to run industrial processes and as an additional heater.

How it works: the steam produced by this boiler can use a water tube type or fire tube boiler, the resulting steam has a large capacity and medium pressure.

Commercial Boiler

This type of commercial boiler has characteristics: its main use is as a producer of steam or hot water as a heater and in addition to running the commercial operation process.

How it works: the steam produced by this boiler can use a water tube type or fire tube boiler, the resulting steam has a large capacity and low pressure.

Residential Boiler

This type of residential boiler has characteristics: its main use is as a producer of steam or low pressure hot water used for housing.

How it works: the steam produced by this boiler uses a fire tube boiler type, the resulting steam has a low pressure and capacity.

Heat Recovery Boiler

This type of heat recovery boiler has characteristics: its main use is to produce steam from unused hot steam. These steam results are used to run industrial processes.

How it works: the steam produced by this boiler uses a water tube boiler or fire tube boiler type, the resulting steam has a large pressure and capacity.

D. Based on boiler construction:

Package Boiler

The package boiler type has the characteristics: boiler assembly is carried out at the manufacturer’s factory, direct delivery in the form of a boiler.

Site Erected Boiler

The site erected boiler type has characteristics: boiler assembly is carried out at the place where the boiler will be established, delivery is made per component.