Moisture Measurement

28/05/2015

Humidity and Moisture

Department of Chemical Engineering, Afe Babalola University © 2015

Humidity
• Moisture measurement are important in the process industry
because moisture can affect products, poison reactions, damage
equipment, cause explosions, etc.
• There are two methods of moisture measurement:
 Absolute measurement method




Provide primary output which can be directly calibrated in terms of dew
point temperature, molar concentration or mass concentration.

Relative humidity method


Provide primary output which can be directly calibrated in terms of
humidity and saturation of moisture.

Department of Chemical Engineering, Afe Babalola University © 2015

1

28/05/2015

Moisture Measurement
• Moisture measurement are important in the process industry
because moisture can affect products, poison reactions, damage
equipment, cause explosions, etc.
• There are two methods of moisture measurement:
 Absolute measurement method




Provide primary output which can be directly calibrated in terms of dew
point temperature, molar concentration or mass concentration.

Relative humidity method


Provide primary output which can be directly calibrated in terms of
humidity and saturation of moisture.

Department of Chemical Engineering, Afe Babalola University © 2015

Moisture Measurement
• Moisture measurement are important in the process industry
because moisture can affect products, poison reactions, damage
equipment, cause explosions, etc.
• There are two methods of moisture measurement:
 Absolute measurement method




Provide primary output which can be directly calibrated in terms of dew
point temperature, molar concentration or mass concentration.

Relative humidity method


Provide primary output which can be directly calibrated in terms of
humidity and saturation of moisture.

Department of Chemical Engineering, Afe Babalola University © 2015

2

28/05/2015

Methods of Moisture Measurement
• Capacitance Method



Utilizes a high dielectric constant of water for its in solution.
The amount of current that flows through the capacitor plate is
proportional to the amount of moisture present.

• Oxides Sensors



Aluminium oxide (phosphorus pentoxide) can be used as sensor for
moisture analysis.
The electrical conductivity of between gold and aluminium
(phosphorus) determines the amount of water in ppm.

Department of Chemical Engineering, Afe Babalola University © 2015

• Dew Point



For many applications, dew point is the desired moisture
measurement.
When concentration is desired, the relation between water content
and dew point is well known and available.

• Photometric method

Department of Chemical Engineering, Afe Babalola University © 2015

3