# Modern Day boiler treatment, a crash course



## Medlabplumbing (May 26, 2011)

So I feel like writing a crash course in modern boiler chemical injection theory. most of this applies to boilers in the 100-300HP range (thats 6million BTU's correct my math im not checking)
The basic concept is this.
1. Boilers take water in and evaporate the pure water and leave "dirty water". Stuff left in the water is TDS total dissolved solids and is removed with a "blowdown pipe" from the top and one from the bottom.

Phosphate used to be injected into boilers and carbonate species that survived the MANDATORY water softening (zeolite ion exchange process) would fall to the bottom and become a "mobile sludge" and through bottom blowdown they would be removed as semisolids.
The TDS would be removed by TOP blowdown after a calculated period of time which is based on feed water to condensate ratio and rate of evaporation, a minimum for a 24hour constant operational boiler is once every 12 hours if at medium firing rate, blowdown MUST be metered by a 2/3rds restriction or a list of unmentioned problems will occur. no longer the ten seconds and two inline specialty throttling valves must be installed.
the TDS is controlled by the top and mobile sludges by bottom blowdown.

*New way*: we now use special polymers that bond to the same afformentioned TDS and float it to the top blow down only, bottom blow down is now a twice a month.

2.* Steam and condensate pipes*- these pipes will corrode naturally, so a chemical must be injected to prevent that, a condensate system will pick up oxygen and carbondioxide as steam cools to liquid and is exposed to air, these added gasses are corrosive.
we inject chemicals that come in three varients that degrade at predictable rates so depending on the total developed length of the system you use 1, 2 or 3 to protect the entire system. As one is consumed another will go a farther distance, for extremely long systems (1mile+) using multiple injection points is recommended.

3. *feedwater- *As the boiler creates steam it consumes water, the condensate coming back IS NOT the same anount as the water we boiled since some is lost to process loss/leaks and the soon to be mentioned Deaerator. So we add new water deemed MAKEUP WATER it is *feed water* once mixed with condensate return. Feed water MUST be 100% softened with NO more than 2ppm and .05 PM is strongly preffered.
Sodium sulphite must be added after the feedwater is mixed and prefferably heated by a blowdown supplied heat exchanger. sodium sulphite will remove the remaining 7PPB (yes billion) o2 (oxygen) present in the water after DEAERATION (the process of enclosing water and mixing it at high velocity with turbulent steam with a temperature of 230-240F, Two passes through two different devices accomplishes the mechanical deaeration, the chemical dearation occurs during and after the mechanical.

some tips
when looking at a phosphae based boiler internally look for a dark purple almost maroon color to the steel, less of a coating more of a pigment, if present proper phosphate concentrations were probably maintained. 

ill add more later


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## nhmaster3015 (Aug 5, 2008)

Fascinating Mr. Spock


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## U666A (Dec 11, 2010)

nhmaster3015 said:


> Fascinating Mr. Spock


I agree, well done. I was lightly involved with the start/test/balance procedures when I was an apprenti at a high rise.

A wee bit technical for me I will admit, but very informative if it is accurate.

Thanks for sharing,
UA


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## Protech (Sep 22, 2008)

Medlabplumbing said:


> So I feel like writing a crash course in modern boiler chemical injection theory.
> 
> <snip>
> 
> *ill add more later*


So what's up there guy? You gonna leave us hanging or what?


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## Airgap (Dec 18, 2008)

Protech said:


> So what's up there guy? You gonna leave us hanging or what?


I bet you would really enjoy Boiler work PT, and be real good at it too...


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## Protech (Sep 22, 2008)

I made him a better web page. I figure this is a good place to drop a link.

www.orlandoboilerservice.com


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