Treatments program

The quahty of feed water required depends on boiler operating pressure, design, heat transfer rates, and steam use. Most boiler systems have sodium zeohte softened or demineralized makeup water. Feed-water hardness usually ranges from 0.01 to 2.0 ppm, but even water of this purity does not provide deposit-free operation. Therefore, good internal boiler water treatment programs are necessary. 

Chelant Control. Chelants are the prime additives in a solubilizing boiler water treatment program. Chelants have the abihty to complex many cations (hardness and heavy metals under boiler water conditions). They accomplish this by locking metals into a soluble organic ring stmcture. The chelated cations do not deposit in the boiler. When apphed with a dispersant, chelants produce clean waterside surfaces. 

Polymer-only Treatment. Polymer-only treatment programs are also used with a degree of success. In this treatment, the polymer is usually used as a weak chelant to complex the feed-water hardness. These treatments are most successful when feed-water hardness is consistently low. 

Clean boiler water surfaces reduce potential concentration sites for caustic. Deposit control treatment programs, such as those based on chelants and synthetic polymers, can help provide clean surfaces. 

New chemical treatment programs were proposed that would permit reduction of staining at a higher pH and markedly reduce corrosion. 

Reducing pH usually has a beneficial effect on corrosion caused by alkaline substances. However, this seemingly obvious solution has a number of drawbacks. Chemical treatment programs work most effectively in certain pH ranges. Decidedly acidic waters can cause corrosion problems as bad or worse, albeit different, than those caused by alkaline waters. Finally, if concentration mechanisms such as evaporation or condensation are present, merely decreasing pH may prove ineffective in controlling attack. 

The following guidelines for establishing an emergeney treatment program should be doeumented or refereneed in the safety plan ... 

They can only carry out these functions consistently and efficiently if the feedwater (FW) and boiler water (BW) chemistry and the overall boiler operation are properly controlled. Thus, over the years, in addition to improvements in engineering design and practice, many different forms of external water treatment processes and internal water treatment programs have been developed. 

Furthermore, to obtain the maximum benefit, BW treatment programs demand an innovative and proactive mindset from owners, oper-... 

These steam generators are often used for once-through steam processes as such, they are not usually provided with any form of water treatment program and are not considered further in this text. 

All industrial WT boilers require good quality FW, and to ensure a full boiler life span (which may be 60 years or more) the water treatment program and its implementation must be first class. 

The process of heating water usually produces sludge and sediments (primarily noncrystalline precipitated salts) in the boiler s waterside dmms and tubes. (Sludge production may be deliberately encouraged in certain forms of internal water treatment programs.)... 

Thus, to correctly assess initial treatment program needs and to regularly monitor subsequently progress, it is necessary to be able to sample all sources of water that contribute to the boiler FW. 

For smaller facilities this is not always the case, and many boiler houses will not necessarily require the presence of permanent operators, which can sometimes make the smooth implementation and seamless operation of a water treatment program quite difficult to achieve. 

In addition, attention must be paid to the BW internal treatment program. Such programs involve the dosing of small amounts of polishing chemical treatments to specified points in the water-steam cycle system, often continuously and proportional to water flow or steam demand, to provide a desired inhibitory or protective effect. 

Also, the particular boiler plant water-steam chemistries must be reviewed and interpreted at regular intervals. The specifics and complexity of this work depend on the type of boiler plant involved and the respective chemical treatment programs employed. The frequency of testing may range from hourly to perhaps monthly, again depending on the type of boiler operation. 

A periodic review of ongoing water treatment programs with regard to suitability, economic benefit, training needs, and technical objectives also is required. 

Senior facilities managers should never abrogate responsibility for final review of water treatment programs. Such programs may be com-... 

In each and every boiler plant around the world, almost without exception, the absence of a decent water treatment program most certainly will ensure that these operational and economic benefits are not attained. Cooperation is required between all parties, and in practice the necessary water treatment functions are inextricably interwoven within the daily mechanical operation of the overall boiler plant. 

As a minimum, such boiler water treatment programs typically require ... 

Thus, the entire thrust of a water treatment program requires a proactive approach to potential problem identification and resolution. The scope of the program should therefore be wide enough to include not only all relevant conditioning equipment and chemical treatments but also a variety of technical and operational support services. 

Service company representatives and other personnel involved in implementing a BW treatment program must regularly attend to a number of basic operational functions, including ... 

Reviewing with the customer s operators and management the current waterside status and new problems identified, current treatment program progress, and future objectives... 

Thus, it is the combination of both external conditioning and internal treatments, together with some level of associated technical and support services, that most properly comprises a comprehensive BW treatment program. 

Thus, in practice, most treatment programs are specifically tailored for the boiler plant in question. The program must then be properly and quickly integrated into normal day-to-day operating practices in order for the boiler plant owner to gain long-term economic and operational... 

These various problems may arise under several different circumstances. For example, difficulties may result from consistently poor operational control of the boiler plant or from enforced operating conditions that fall outside generally accepted procedures. Alternatively, problems may stem from malfunctioning equipment, from equipment design flaws, from inadequate water treatment programs, or even as a result of poor interpretation of monitored results and bad water treatment advice. 

Most HW and LP steam boilers (i.e., those that operate below 15 psig) and many smaller high-pressure (HP) steam-raising boilers employ, at best, relatively simple methods of FW pretreatment and a basic internal chemical treatment program. Many times no pretreatment is provided. 

Where MU requirements are high, irrespective of absolute boiler output, more sophisticated water conditioning is usually warranted than would otherwise be provided. Also, as boiler output and operating pressures increase and heat and mass transfer issues become more critical, so the demand for more exacting water treatment programs, monitoring, and control activities increases in importance. 

With an inadequate BW treatment program, the resultant water chemistry may permit the very gradual (but persistent) formation of scaling deposits, the development of which may go unnoticed for some considerable time. 

The limitation of free caustic in the boiler by modifying the water treatment program and maintaining the FW and BW chemistry within new, close-range parameters... 

The more extensive use of pretreatment equipment generally is a commendable approach, although it is difficult to externally overtreaf boiler MU and FW, it also is pointless to spend limited capital resources installing sophisticated equipment to provide high-purity water and then to subsequently add dissolved solids back into the FW or BW with an inappropriate, internal chemical program. Both external and internal water treatment programs must be compatible and mutually beneficial ... 

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