How to approach Condensation

Condensate recovery is amongst the areas of strength conservation so widely used in industries today. Condensate still has about 20% of saturated steam, along with being distilled normal water, almost without dissolved solid waste. Therefore , it has the recovery provides advantages to boilers including reducing gasoline or diesel costs, lessening chemical treatment, conserving water, and increasing boiler efficiency. Non-contaminated condensate, which can be the product from non-contact steam application, dividends to water vapor boiler's system as materials water. There is two types in condensate getting system in boilers -- the pressurized condensate system and the gravity-vented condensate program. The whizz steam by high pressure condensate is saved by going back this condensate to the deaerator while the gravity-vented condensate results to the boiler feed water tank.

Oxygen Harm

Often people reported due to its pureness in characteristics; steam condensate requires simply no chemical cure, but is that so? Condensate is corrosive and can be dirtied by rusts, something that a small number people are aware. Sometimes, condensate can be a little acidic. Because of this , condensate dispatch deteriorates swifter than steam piping. Oxygen corrosion takes place in condensate piping while pitting, which is the most harmful form of corrode.

The reaction from oxygen invasion is:

4Fe + 6H2O + 3O2 4Fe(OH)3
Carbonic acid solution thins condensate pipes to result in grooving towards the bottom section of the pipes. The outcome is, when a condensate tubing has mostly pitting, the condensate is high in oxygen, however, if the pipe outlet is thinning, the condensate pipe suffers from carbonic acid attack. Yet , where perform oxygen and carbon dioxide on condensate broiling originate from? Are not all blended oxygen and carbon dioxide for boiler water arrested by artificial means by the deaerator and chemically by salt sulphite or perhaps DEHA from the boiler? Definitely, there are two main reasons because of this phenomenon. Earliest, when steam condenses, the flow quantity shrinks thus allowing o2 to infiltrate and break down. Secondly, oxygen can also be pulled into condensate system through condensate high heel platform sandals, leaking heating exchangers, and vents in condensate receiving tanks.

Acid solution Corrosion

Carbon can mess up in the same way since oxygen, nevertheless, the main way to obtain carbon dioxide on steam is a breakdown of bicarbonate and carbonate alkalinity in boiler water to make carbon dioxide.

Allow me to share the typical reactions that take place:

Carbonate response: CO3 + H2O CO2 & 2OH
Bicarbonate reaction: 2HCO3 + high temperature CARBON + 2H2O
Carbon dioxide combines with steam, condenses on condensate to create weak carbonic acid, and lowers the pH. Condensate is so genuine that also small amount of poor carbonic chemical can drop the pH to 5. 5.

The response is:

In Malaysia, there was an incident in a petrochemical industry just where less than twenty percent of the condensate was came back into the furnace because of carbonic acid infiltration. In central heating boiler, acidic condensate lowers pH, erodes sheet metal, increases melt iron, and increases the total dissolved colours (TDS) as iron bicarbonate. Iron bicarbonate mixes with boiler liquid to form iron oxide and carbon dioxide, and therefore the carbon mixes with steam again. That is why a number of people cannot keep a high pH in their boilers despite doubling the dosing of caustic soda. This concern in condensate recovery can be disadvantageous to steam boilers and should be prevented.

Proper protection

Protection in after-boiler condensate lines becomes necessary. Corrosion on condensate series can be lessened by unpredictable amines as corrosion inhibitors. Volatile amines commonly used pertaining to condensate collection protection at this time are neutralizing amines and filming amines. Neutralizing amines react with carbonic chemical and co2 to increase condensate pH to 9. One of the commonly used neutralizing amines is cyclohexylamine. Filming amines, on the flip side, form defending films at metal types of surface and shield from air attack, not much different from the way magnetite film does. A good example of filming amines is octyldecylamine. Having oil-like property, filming amines coat the steel surface with one-molecule heavy. Filming amines have no effect on condensate pH. Carbon dioxide and oxygen tend to be corrosive in combination. Accordingly, if a system encounters both o2 and chemical attacks, various both amines is always advised.

Besides substance treatment, condensate quality monitoring should be enclosed on the daily or regular basis. Require a test from condensate to monitor in terms of iron content, solidity, and TDS. Check for color and purchase. Any change indicates inappropriate treatment or perhaps contamination. not treated to remove contamination, therefore , to stop iron hydroxide infiltration; over unity magnetic filter might be applied to take it off from condensate. Total iron in furnace feed liquid for choice pressure boiler should be less than 0. 05 ppm, and any sort of increase can mean iron bars hydroxide infiltration from the condensate line. Intended for boiler operating below twenty bars, a recommended alkalinity status is one hundred and forty to 800 ppm. In case the alkalinity level exceeds seven-hundred ppm, bicarbonate and carbonate will pack in producing carbon dioxide and drive in heavy steam, as stated just before. However , the best method is to remove the alkaline hardness (carbonate and bicarbonate) conclusively by using the reverse-osmosis system as well as demineralization.


Finally, condensate is rust and detrimental to condensate piping. The danger happens when various steam technicians, based on decent boiler liquid field-test outcomes, feel comfortable with the boiler normal water treatments. A few engineers do not ever seriously consider or even realize the damage that can happen to all their condensate marks. This is a serious negligence. Once leaks soon after leaks happen to be detected, it really is too late and costly vehicle repairs would be expected. It is the remedying of condensate go back that makes it pointless to replace condensate piping for several years.