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    Condensate recovery is among the areas of energy levels conservation hence widely utilized in business today. Condensate still has about 20% of fats steam, along with being distilled liquid, almost free from dissolved shades. Therefore , it has the recovery supplies advantages to boilers including reducing energy costs, minimizing chemical treatment, conserving water, and increasing central heating boiler efficiency. Non-contaminated condensate, which can be the product from non-contact heavy steam application, comes back to water vapor boiler’s system as supply water. There is two types of condensate receiving system through boilers – the pressurized condensate program and the gravity-vented condensate program. The flash steam out of high pressure condensate is reclaimed by coming back this condensate to the deaerator while the gravity-vented condensate profits to the boiler feed reservoir.

    Oxygen Strike

    Often people says due to its pureness in aspect; steam condensate requires zero chemical treatment, but usually so? Condensate is rust and can be infected by rusts, something that very few people are informed. Sometimes, condensate can be slightly acidic. This is why condensate conveyor deteriorates swifter than steam piping. Oxygen corrosion occurs in condensate piping since pitting, which is the most detrimental form of corrode.

    The reaction from oxygen invasion is:

    4Fe + 6H2O + 3O2 → 4Fe(OH)3

    Carbonic acid thins condensate pipes and causes grooving at the bottom section of the pipes. The end result is, if a condensate water pipe has mostly pitting, the condensate is high in oxygen, although if the pipe wall membrane is thinning, the condensate pipe is affected with carbonic acid solution attack. Nevertheless , where accomplish oxygen and carbon dioxide through condensate pipes originate from? Are not all dissolved oxygen and carbon dioxide on boiler liquid arrested by mechanical means by the deaerator and chemically by salt sulphite or DEHA in the boiler? Basically, there are two main reasons in this phenomenon. Initially, when heavy steam condenses, the flow amount shrinks therefore allowing o2 to mess up and reduce. Secondly, oxygen can also be drawn into condensate system throughout condensate heels, leaking high temperature exchangers, and vents from condensate receiving tanks.

    Chemical Corrosion

    Co2 can bypass in the same way because oxygen, even so, the main source of carbon dioxide through steam is a breakdown from bicarbonate and carbonate alkalinity in central heating boiler water to form carbon dioxide.

    Let us discuss the reactions that transpire:

    Carbonate reaction: CO3 + H2O → CO2 & 2OH

    Bicarbonate reaction: 2HCO3 + heating → CARBON DIOXIDE + 2H2O

    Carbon dioxide combines with heavy steam, condenses through condensate to form weak carbonic acid, and lowers the pH. Condensate is so genuine that possibly small amount of weak carbonic acid solution can drop the pH to five. 5.

    The reaction is:


    In Malaysia, there was an incident in a petrochemical industry where by less than twenty percent of the condensate was went back into the central heating boiler because of carbonic acid infiltration. In central heating boiler, acidic condensate lowers pH, erodes material, increases break down iron, and increases the total dissolved solid waste (TDS) when iron bicarbonate. Iron bicarbonate mixes with boiler standard water to form flat iron oxide and carbon dioxide, and therefore the carbon mixes with steam once again. That is why some individuals cannot keep a high pH in their boilers despite duplicity the dosing of caustic soda. This issue in condensate recovery is normally disadvantageous to steam boilers and need to be prevented.


    Protection in after-boiler condensate lines is needed. Corrosion during condensate series can be decreased by unpredictable amines seeing that corrosion inhibitors. Volatile amines commonly used designed for condensate line protection at this time are neutralizing amines and filming amines. Neutralizing amines react with carbonic chemical and carbon to increase condensate pH to 9. Among the commonly used neutralizing amines is normally cyclohexylamine. Filming amines, however, form safety films with metal materials and safeguard from much needed oxygen attack, similar to the way magnetite film does. Certainly one of the filming amines is octyldecylamine. Having condensation reaction -like property, filming amines overcoat the sheet metal surface with one-molecule heavy. Filming amines have no effect on condensate pH. Carbon dioxide and oxygen are definitely more corrosive in combination. Accordingly, if the system confronts both much needed oxygen and chemical attacks, a blend of both amines is always advised.

    Besides chemical substance treatment, condensate quality monitoring should be integrated on the daily or every week basis. Require a test from condensate to monitor straightener content, solidity, and TDS. Check for coloration and purchase. Any change indicates poor treatment or contamination. Condensate is not treated to remove toxins, therefore , in order to avoid iron hydroxide infiltration; permanent magnetic filter can be applied to remove it from condensate. Total golf club in central heating boiler feed normal water for moderate pressure boiler should be minimal than zero. 05 ppm, and any sort of increase may mean in terms of iron hydroxide infiltration from the condensate line. Intended for boiler operating below 12 bars, a recommended alkalinity score is one hundred and forty to 900 ppm. Should the alkalinity level exceeds seven-hundred ppm, bicarbonate and carbonate will pack in producing carbon dioxide and entrain in water vapor, as stated before. However , the best method is to take away the alkaline solidity (carbonate and bicarbonate) once and for allonce for all by using the reverse-osmosis system as well as demineralization.


    Finally, condensate is corrosive and destructive to condensate piping. The risk happens when many steam engineers, based on decent boiler drinking water field-test outcomes, feel comfortable with their whole boiler normal water treatments. A bit of engineers hardly ever seriously consider or realize the damage that can happen to their very own condensate lines. This is a heavy negligence. When leaks immediately after leaks will be detected, it can be too late and costly improvements would be inescapable. It is the remedying of condensate return that makes it extraneous to replace condensate piping for quite a while.

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