Boiler Plant Subsystems, Appurtenances, and Auxiliaries

Modem HW-generating and steam-raising facilities comprise a number of often complex, interdependent boiler plant subsystems, appurtenances, and auxiliaries, with large process, utility, and cogeneration boiler plants being especially complex. This chapter provides notes on many of the various boiler plant subsystems and types of equipment employed as an introduction to considering the waterside problems that may be encountered therein. 

Hot water generators are the simplest systems overall, although many larger institutional and commercial hydronic heating plants contain fairly complex distribution systems that may include high and low flow rate subsystems and primary and secondary piping schemes in either series or parallel configurations. 

Compared to HW generators, steam-raising plants contain additional safety devices and become increasingly more complex as they become larger. Irrespective of size, all steam-raising plant facilities contain interdependent subsystems that are essentially the same in nature and purpose. 

Larger steam-raising boiler plants may be physically divorced from factory areas, and the very largest tend to contain systems and equipment housed in a number of separate facility areas or buildings. As a limited example, these facilities may include  

Water pretreatment plant Waste water treatment plant 

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