Temperature, Condensation Point & Maximum Achievable vH2O2 ppm in Bio-decontamination

This blog is the third in a 4-part series where we describe how process parameters influence vaporized hydrogen peroxide bio-decontamination applications.

• First blog: Humidity
• Second blog: Solution Concentration

In this series, we propose four basic process parameter rules.  This blog focuses on the third rule: 

Increasing the temperature increases the amount of water and hydrogen peroxide vapor the air can hold, thereby increasing the maximum achievable vH₂O₂.

In our previous blogs in this series, the bio-decontamination cycle temperature was maintained at 23 °C for all exemplar cycles. At a given temperature, air can only hold a certain amount of vapor, whether H₂O or H₂O₂. Now will will demonstrate how changing the temperature can change both the condensation point and the maximum achievable hydrogen peroxide vapor concentration.

Figures 3a and 3b (below) show two bio-decontamination cycles. The cycle represented by black lines indicates a process temperature of 40 °C and the blue lines represent temperature at 23 °C. In both cases, dehumidification is performed to lower humidity to 10% prior to conditioning and both use the same H₂O₂ solution concentration (59 m-%). The black line in Figure 3b shows that temperature at 40 °C allows a higher ppm vH₂O₂ than temperature at 23 °C.

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We can further examine the effect of temperature by looking at humidity, both relative humidity and relative saturation values. (Read about relative saturation.)

Figure 4 below shows ppm vH₂O₂ with temperature at 5°C. Relative saturation is on the x axis and relative humidity is on the y axis. The coordinate lines within the x and y axes represent H₂O₂ vapor concentration from 0 ppm to around 500 ppm. The 0-ppm line represents a vapor that has been created using pure water only. When the H₂O₂ solution concentration is increased, the vH₂O₂ also increases. Theoretically, the line along the X-axis represents a vapor that has been created using 100% H₂O₂ liquid. Condensation occurs once relative saturation is 100% RS and ppm vH₂O₂ cannot be increased thereafter. Thus, with temperature at 5 °C, initial relative humidity at 0% RH, and vaporizing an H₂O₂ solution of 100 m-%, the theoretical maximum achievable ppm vH₂O₂ is 548 ppm.

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All conditions in Figure 5 are the same as Figure 4 (0% RH, 100 m-% solution), and only temperature is changed to 50 °C. The theoretical maximum achievable ppm vH₂O₂ is now 13,019.

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Figure 6 shows the maximum ppm vH₂O₂ at various temperatures and using different H₂O₂ solution concentrations. We compare two frequently used H₂O₂ solution concentrations: 35% and 59%. The blue trend line represents a 35% H₂O₂ solution. With temperature at 40 °C, the maximum achievable ppm vH₂O₂ is 4,210. At the same temperature (40 °C), a 59% H₂O₂ solution gives a maximum achievable ppm vH₂O₂ of 5,461.

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Read about all four rules in the white paper: Considering Condensation: Influences in Hydrogen Peroxide Vapor Bio-decontamination

Read the fourth blog.

We invite you to view a recorded webinar on this topic.  

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