Boiler Plant Subsystems

Within these tortuous systems there exists considerable opportunity for process contamination, corrosion, and equipment malfunction to occur, with cause-and-effect problems creating further impact downstream and placing additional demands on monitoring and control efforts. 

Another difference between utilities and factories is that most industrial facilities tend to operate boiler plants with a lower quality (and often variable) FW compared to power generators. Although boiler heat flux is usually lower, this practice nevertheless adds an additional water chemistry control burden, especially because most factories do not employ chemists with specific water chemistry duties. 

Additionally, because most factories do not operate steady-state processes, the efforts to match steam output to variable production department steam demands may further tax the boiler plant s generation capacity and manpower resources. 

NOTE As a consequence of the different kinds of operational and management problems associated with raising steam in industrial boiler plants, it often requires a different mindset than that needed for a base-load utility power house, where personnel strive to maintain steady-state (but knife-edge) operating conditions. The differences between industrial plants and power generators is also reflected in the waterside chemistries and monitoring and control objectives of their respective boiler plant systems. 

Hot water generators and LP steam-raising plants of below 15 psig are designed to operate with minimal blowdown and to suffer negligible circulatory losses. As a result, clean, sediment-free water of almost any characteristic nature (e.g., soft and corrosive or hard and scale-forming) is likely to be suitable as a source of boiler water makeup. 

---

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. 

---