Low Toxicity
Oxygen Scavengers

The ZI-CHEM® product range includes oxygen scavengers for a wide range of operating conditions and application requirements found in industrial steam generating applications.

Some of the key criterion that is considered when selecting the most suitable oxygen scavenger for a given application includes:

  • Oxygen exchange capacity
  • Speed of reaction with oxygen
  • Contribution to boiler dissolved solids and resultant blowdown or scale deposition
  • Degree of volatility
  • Metal passivation capability
  • Solubilization of surface iron and copper oxides
  • Toxicity
  • Degree of carcinogenic risk

Oxygen scavengers such as hydrazine have been used extensively in the past, and in some places are still in use. However there is now increased awareness that hydrazine is highly toxic to humans and is also a suspected carcinogen.

Within the ZI-CHEM® product range there are many safer¬†alternatives¬†to hydrazine that exhibit equal or higher performance but have little or low toxicity and are non¬†carcinogenic.

A summary of the features of the most common components contained in these products of these is shown below:

Chemical Oxygen Scavenging Passivation Volatility Breakdown Pressure Residual Testing Safety
Sodium (Bi~) Sulfite (Na; SO3, NaHSO3) Excellent Little to None Non-Volatile 900-1250 psig SO2, H2S Very Good (BoilerWater) FDA Acceptable
Erythorbate
(C6H7O6Na)
Very Good Excellent Non-Volatile 1200-1600 psig CO2, Organic Acids Good (Feedwater) GRAS
Methylethyl ketoxime
C4H8NOH
Good Excellent Excellent 1250 psig NH3, N2O, N2, MEK Good (Feedwater) Moderately Toxic
Diethylhy droxylamine
(C2H5)2NOH
Good Very Good Very Good 300 psig NH3, NO2, NO3, Amines, Acetate Good (Feedwater) Moderately Toxic
Hydroquinone
C6H6O2
Very Good Good Non-Volatile (Steam Distills) 1300 psig CO2, Organic Acids Good (Feedwater) Mutagenic
Carbohydrazide (N2H3)2CO Good Fair Poor 235 psig NH3,N1, CO2 Poor (Feedwater) Unstudied
Hydrazine
N2H4
Good Good Poor 235 psig N2, NH3 Very Good (FeedWater) Suspect Carcinogen