Deoxygenation by substitution with N2

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One special pipe applying aerodynamics goes beyond conventional reaction and mixing levels.OHR MIXER

OHR method is the most efficient and fastest deoxygenation treatment on the market.

When oxygen is dissolved in liquid, deoxidation treatment is carried out in chemical plants when there is a danger of an
explosion in the chemical reaction process or where dissolved oxygen inhibits the chemical reaction.
A common deoxidation process in chemical plants is a method of blowing nitrogen gas into liquid which has oxygen gas
dissolving into it in order to increase the concentration of dissolved nitrogen in the liquid. Dissolved oxygen concentration
decreases by the increase of the dissolved nitrogen concentration. In other words, oxygen gas is substituted with nitrogen
gas and dissolved oxygen is removed.

The conventional method requires a large amount of nitrogen gas bubbling for a long time.

Deoxidation by nitrogen gas is very difficult.

According to the conventional method, it is necessary to deoxidize for a very long time such as 24 hours when the targeted
deoxygenation rate is high (e.g. 95%, 99% or 99.9% removal). In addition this method needs a large amount of nitrogen gas
bubbling in the liquid in a large tank so only batch processing can be done. This method wastes a lot of time and money.
Due to this problem, the lead time of the production line becomes very long and inefficient.

The OHR method can be used for continuous processing work,
and DO can be removed from 10.0 mg/L to 0.2 mg/L.

High efficiency deoxygenation can be easily done with OHR method. For example even in a very difficult case where the DO
value is 10.0mg/L and it is necessary to deoxidize it to 0.2mg/L (=oxygen removal rate is 98%) the process can be done
continuously in just a few seconds. No need for pressurization / decompression and to add chemicals at all.

You can learn about the OHR method of high efficiency deoxygenation treatment in the documents containing illustrations
and test data. Please contact us.


Why OHR method can achieve high efficiency deoxygenation instantaneously.

There is no technology other than OHR to raise the dissolved nitrogen concentration in liquid to supersaturation by 30%.

  • (1) The saturation value of "air" dissolved in water at 20°C is about 24mg/L. This means 24mg of air dissolves in 1 liter of water.
    This 24mg/L of dissolved air includes 15mg/L of nitrogen gas and 9mg/L of oxygen gas. (*The air contains other gases including
    argon, carbon dioxide, neon, helium, and other trace gases but these are in very small quantities. So we will explain here that
    these trace gases can be ignored.)
  • (2) The air contains 78% nitrogen gas and 21% oxygen gas. So when air dissolves in water, both oxygen gas and nitrogen gas
    dissolves in water at the same time. Therefore in water that requires deoxygenation treatment nitrogen gas is dissolved to
    almost saturation point.
    When the air dissolves in water, nitrogen gas dissolves up to 15mg/L and oxygen gas dissolves up to 8.84mg/L (both values are
    at saturation value at 20°C, 1 atm). During the deoxygenation treatment pure (100% concentration) nitrogen gas is dissolved in
    water and the dissolved nitrogen gas concentration increases to 19mg/L (saturation value at 20°C, 1 atm).
  • (3) Even though pure nitrogen gas dissolves in water which has 15mg/L of nitrogen gas, dissolved nitrogen gas concentration is
    increased up to only 19mg/L (=nitrogen gas concentration will rise only 4mg/L). Thus it is very difficult to remove dissolved
    oxygen in water by simply blowing nitrogen gas because it requires a lot of time such as 24 hours.
  • (4) Then, how can we remove dissolved oxygen in water quickly and continuously? To do this, it is necessary to dissolve nitrogen
    gas at once to a "oversaturated point”.
  • (5) Why can the OHR method achieve high efficiency deoxidation treatment in just a few seconds? The reason is that the
    concentration of dissolved nitrogen in liquid can be increased to 30% oversaturation level (saturation value is set at 100%,
    OHR can dissolves gas up to 130%). 5% or 10% oversaturation level is not enough. In order to instantaneously remove dissolved
    oxygen, a powerful gas-liquid mixing / reaction technology that can raise the dissolved nitrogen concentration to 25mg/L is

See the graph on the right.
The graph shows how much oxygen can be oversaturated
using three different units.
(Measured by Tokyo University of Marine Science and Technology)

F company’s micro/nano bubble generator reaches
only 4.4% oversaturation.
OHR micro/nano bubble generator reaches 30.7%

OHR has ability to dissolve the oxygen concentration at 130% oversaturation means that likewise OHR also has the ability to
oversaturate the nitrogen concentration to 130% similarly.
The above data shows that there is a big difference in the performance of microbubble generators that are sold on the market.
For details on how to judge the superiority / inferiority of microbubble generators, please see the link below.
Criteria for judging superiority / inferiority of microbubble generators

The OHR method can achieve highly efficient deoxygenation treatment because of its very powerful gas-liquid mixing / reaction
ability. So 10mg/L of dissolved oxygen can be reduced to 0.2mg/L continuously.

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