Package boiler is a boiler that had been fabricated and available as a complete package. The entire pressure parts have been assembled in the workshop and ready to be sent to the field or site where power plant is located.
On the field/site requires only connection and integration of course work in electrical connections, water pipes, steam pipes and fuel piping system to operate. Package boiler is one of classification of boiler based on erection. Design package boilers in general are the type of Fire Tube Boiler and have made up shell and tubes. This type has high heat transfer both radiation and convection.
Package boiler has the following characteristics:
- Package boiler has higher level of thermic efficiency than other types of steam boilers.
- A number of passes generate better heat transfer overall.
- Induced or forced draft system generates proper combustion efficiency.
- A large number of small diameter tubes can make package boiler has good convection heat transfer.
- The small dimension of combustion chamber/furnace and the high heat which is released will result in more rapid evaporation.
Figure 1: Package Boiler
(Source: Spirax Sarco)
Package boilers can be classified based on the number of passes which mean the number of times the combustion gases through the boiler. The combustion chamber is placed as the first pass after the later one, two, or three sets of fire tubes. The most common type of boiler in this class is unit of three passes with two sets of fire tubes and exhaust gases exiting from the back boiler.