Water Condensate Treatment

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In order to ​preserve the ​system and ​ensure ​longevity and ​peak efficiency,​ the water ​condensate from ​the steam ​boiler should ​be treated.​  ​

How do I best ​manage and ​treat the ​condensate? ​

Specifically, ​how can I treat ​the light ​steep water ​vapour ​condensate from ​the corn ​industry?  ​

It has a pH ​between 2 and 2.​5, COD around ​7000 and ​soluble protein ​1 wt.  ​

Additionally, ​how can I best ​treat the ​condensate to ​return it to ​the boiler and ​save water and ​energy?  ​

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10 Answers

  2. Dear Mr.Azim Gul Kazi,

    Its purpose is to control  boiler water  parameters within prescribed limits to minimize scale, corrosion, carryover, and other specific problems.  Blowdown  is also used to remove suspended solids present in the system. Even with the best pretreatment programs, boiler feedwater often contains some degree of impurities, such as suspended and dissolved solids. The impurities can remain and accumulate inside the boiler as the boiler operation continues. The increasing concentration of dissolved solids may lead to carryover of boiler water into the steam, causing damage to piping, steam traps and even process equipment. The increasing concentration of suspended solids can form sludge, which impairs boiler efficiency and heat transfer capability. In addition to proper blowdown practices, including the use of automatic blowdown control, reducing cost and heat loss associated with boiler blowdown can also be achieved through recovering the heat/energy in the blowdown.

    The common impurities in raw water can be classified as follows:  

    1. Dissolved solids.
    2. Suspended solids  
    3. Dissolved gases  
    4. Scum forming substances
    5. Heat,

    Treatment of Boiler Condensate(Blowdown)

    1. Gases removed by degaser tower, air supplied to water.
    2. Ion exchange Process is the best method
    3. Recycle to raw water for further treatment of water if hardness is more.
    4. Heat removed by Heat exchanger i.e. BFW preheater, Installation of heat recovery equipment is valuable only when energy from the flash tank or the blowdown water can be recovered and utilized. When an excess supply of exhaust or low-pressure steam is already available, there is little justification for.
    5. RO,
    6. Hardness removed by pretreatments.

     

  3. Dear Asim,

    you should try membrane(polysulfonate) base filtration to recover condensate water, filtration product water you may directly used in boiler feed & filtration reject water treat as waste water, 60 to 70 %  water you may recover.

  4. Hi Asim,

    I suggest you prepare your mind to treat the condensate (water) from ​​the steam ​​boiler purely as a wastewater. First, you do a complete bacteriological and physicochemical analysis of the condensate water. You may need a treatment plant (size to be determined by volume of water). In your design, you look at a disinfecting unit, Potassium Dichromate (K2Cr2O7) treatment unit to reduce or eliminate organics (reduce COD), coagulating unit, sedimentation unit, Filtration unit, pH adjustment unit ( may use lime, Soda ash or the likes to bring the pH within 7.0), etc. The treated water can then be reused. (You may analyze for the COD, absence/presence of the key contaminants before reuse).

    Regards

    Justin.

  6. The condensed water can be treated in a flotation unit to remove the proteins. The pH should be adjusted between 6.0 and 9.5 to meet the water quality standards contained in local environmental legislation. Then after this treatment the water can be recirculated in the process.

  7. Dear Asim Gul,

    If we compare the wastewater generated from a Boiler Condensate and the wastewater generated from the Process Stream then we come to conclusion that the quantity is far less then that. If you install a system to treat / remove COD and other impurities, will cost you much then to recover. In my opinion, a good management and economical practice is to send it to the main stream and let it be treated with the rest of the wastewater at your wastewater treatment plant. 

     

    You might have an Anaerobic Digester (may be or not post Aerobic Treatment) for your wastewater system. 

    2 Comments

    2. I agree Mansool. It would make far more sense to treat the effluent to a standard where he can recover it to his cooling water system than to attempt to recover it to the demin plant. 

      It will cost him about $1000/Ml to recover the water to the demin plant, based on a 20 year amortisation period, whereas he probably already has a plant that can treat the water to CW feed quality. 

  8. Where is the plant located?

    What is the quantity if Steep water generated per day?

    We can send you the complete treatment scheme to meet the specfications and also recycle the water - send your contact details and we can take this offline from here 

     

    2 Comments

    1. we can supply various wastewater treatment products such as mbbr media, tube settler, aeration diffusers etc. If you have any requirements, pls contact me freely. Email: rita@sintafrp.cn

      Commented on by

  9. In order to recover this water back to the steam generation process, you're going to have to figure out a way to separate the condensate from the rest of the effluent streams and remove the VOCs and other impurities, probably by installing a MBR upstream of a UF/RO. You can then feed RO product into the demin plant. 

     

    1 Comment

  10. This may be an application where you could move air through the system to force the condensate to collect in a pool then filter and treat.  The issue we have found with condensate is the difficulty in controlling it.  Condensate by nature will form on a surface and thereby collect whatever contaminant may be on that surface.  We handle this in liquid storage by controlling air quality and thus moving air to force the condensate to be controlled.  In your case the condensate will be high and therefore need to be filtered so the question is how to collect it consistently.  I suggest to use air to water movement is the answer.

    1 Comment