Online Dissolved Hydrogen Analyzer

AMI Hydrogen QED

Online Analyser for the Continuous Measurement of Dissolved Hydrogen in Water/Steam Cycle

Continuous Measurement of Dissolved Hydrogen
  • Description
  • Specification
  • Application
  • Options
  • Downloads
  • F.A.Q.

Online Analyser for the Continuous Measurement of Dissolved Hydrogen in Water/Steam Cycle.

Dissolved Hydrogen is released as a by-product during the formation of the magnetite and hematite layer in the power plant. Therefore its concentration is a direct measure of the rate of corrosion.

AMI Dissolved Hydrogen Analyzer Features:

  • Measuring range: 0.01 to 800 ppb.
  • Faraday electrode and control unit for automatic sensor verification by electrochemically generated hydrogen in ppb range.
  • Unattended and automatic sensor self-regeneration.
  • Durable membrane and large electrolyte volume in the hydrogen sensor to reduce sensor maintenance.
  • Automatic temperature and air pressure compensation.
  • Digital sample flow monitoring.
  • No reagent/ purge gas is required for operation.
  • Optional communication boards; Profibus DP or Modbus.
  • Factory tested and ready for installation and operation.

  • Transmitter AMI Dissolved Hydrogen Analyzer in a rugged aluminum enclosure (IP 66).
  • Flow cell QV-Flow PMMA OTG made of acrylic glass with needle valve and digital sample flow meter on mounting angle made of stainless steel.
  • Swansensor Hydrogen with platinum anode and integrated NT5k temperature sensor.
  • Faraday electrode for the automatic or manual verification by electrochemically generated hydrogen concentration in the ppb range.
Dissolved Hydrogen Analyzer

Specifications:

  • Measuring range: 0.01 ppb to 800 ppb H2 (at 25°C, 1013hPa) or 0 – 50% saturation.
  • Automatic air pressure compensation.
  • Automatic temperature compensation.
  • Simultaneous measurement of dissolved hydrogen, sample temperature and sample flow.
  • Large backlit LC display showing measuring value, sample temperature, sample flow and operating status.
  • Easy user menus in English, German, French and Spanish.
  • All parameters are easily programmed using the keypad.
  • Two current outputs (0/4 – 20 mA) for measured signals (3rd output optional).
  • Data logging of major process events and calibration data.

Detailed Specification can be found on Page 2 of this Data Sheet.

Application Note: Measuring Dissolved Hydrogen in Water Steam Cycle to Predict and Prevent Potential Corrosion


Every year, corrosion costs the electric utility industry billions of dollars. International guidelines are available for water chemistry control to minimize corrosion. Parameters such as pH, oxygen, iron, hydrogen and others are directly related to corrosion control and used for monitoring corrosion. International technical organizations and power plant chemists are working diligently to find a
suitable method to provide real-time corrosion trend monitoring in their process during commissioning and normal operation.

Hydrogen monitoring in this case is becoming important in corrosion monitoring for water steam cycle [1, 2, 3]. Corrosion occurs in the presence of water contact with iron at high temperature. According to the Schikorr reaction (Eq. 1), hydrogen is released as a by-product during the formation of the magnetite and hematite layer in the power plant. Therefore its concentration is a direct measure of the rate of corrosion.

  3Fe + 4H2O → Fe3O4 + 4H2    (Eq. 1)

During commissioning of a new power plant, commissioning engineers need the formation of uniform iron oxides as a protective layer on the surface of the metallurgy to limit further corrosion of the steel. However, some iron oxides are disrupted and formed again during operation. The disruption and formation of the iron oxides layer will release hydrogen gas. Even though other possible sources of hydrogen exist, measuring dissolved hydrogen concentration in the process will provide valuable indication of an active corrosion rate in the system.

Various tests and research have been carried out to identify suitable sampling points for a representative sample. Hydrogen concentration is commonly measured in the steam or feedwater[4] to ensure that corrosion rates are kept at an acceptable level.

Guidelines for hydrogen levels are not well defined and may vary from plant to plant. Available research indicates hydrogen levels occur at a few ppb (part per billion) during normal operation and as much as several hundred ppb during commissioning. However, hydrogen values greater than 10ppb-50ppb under normal working condition may be an indication of permanent damage to the boiler.

Graph 1 (below) shows typical hydrogen measurement in a once-through superheated steam boiler. The power plant is using oxygen treatment with ammonium as an alkalizing agent in the water steam cycle. Dissolved hydrogen measurement tracking in superheated steam provides an indication of the corrosion trend in the boiler. This information is very useful to plant chemists for corrosion monitoring and control. The plant chemist could take the necessary action to mitigate corrosion. Information in the graph indicates that the corrosion rate is under control.

Hydrogen measurement in once through superheated steam graph

Graph 2 (below) shows hydrogen measurement in feedwater (economizer inlet). The graph indicates increase of dissolved hydrogen in feedwater at various times. This indirectly represents increasing of corrosion rate in the feedwater system. The dissolved hydrogen increase appears before corrosion is excessive. Corrective action was taken to reduce and control corrosion in feedwater.

Hydrogen Measurement in Feedwater

Accessories

  • A-75.400.000 QS-Monitor AMI INSPECTOR Hydrogen.
  • A-81.420.020 AMI Option; Profibus- / Modbus Interface.
  • A-81.420.042 AMI Option; USB Interface.
  • A-81.420.050 AMI Option; 3rd signal output.
  • A-81.420.060 AMI Option; HART Interface.
  • A-88.224.220 Communication cable, AMI to PC, 2 m.
  • V-9700910 Service Hydrogen sensor including calibration and labeling.

Dissolved Hydrogen Analyzer Spare parts

  • A-87.260.001 Swansensor Hydrogen.
  • A-88.155.X20 Sensor cable for Sensors with M16 plug.
  • A-89.811.060 Set of fuses for AMI.
  • 2 Relay outputs Two potential-free contacts program-able as limit switches for measuring values, controllers or timer with automatic hold function. Rated load: 1A / 250 VAC
  • 2 Signal outputs (3rd as option)Two programmable signal outputs for measured values (freely scalable, linear or bi-linear) or as continuous control out-put (control parameters programmable) as current source. 3rd signal output selectable as current source or current sink. Current loop: 0/4 – 20 mA Maximum burden: 510 Ω
  • Optional Profibus- / Modbus Interface
  • Optional HART Interface
  • Optional USB Interface
  • Optional Third 0/4 – 20  mA Output

All Swan Analyzers are CSA Cirtified at our premises before shipping.

Online Analyser for the Continuous Measurement of Dissolved Hydrogen in Water/Steam Cycle.

Dissolved Hydrogen is released as a by-product during the formation of the magnetite and hematite layer in the power plant. Therefore its concentration is a direct measure of the rate of corrosion.

AMI Dissolved Hydrogen Analyzer Features:

  • Measuring range: 0.01 to 800 ppb.
  • Faraday electrode and control unit for automatic sensor verification by electrochemically generated hydrogen in ppb range.
  • Unattended and automatic sensor self-regeneration.
  • Durable membrane and large electrolyte volume in the hydrogen sensor to reduce sensor maintenance.
  • Automatic temperature and air pressure compensation.
  • Digital sample flow monitoring.
  • No reagent/ purge gas is required for operation.
  • Optional communication boards; Profibus DP or Modbus.
  • Factory tested and ready for installation and operation.

  • Transmitter AMI Dissolved Hydrogen Analyzer in a rugged aluminum enclosure (IP 66).
  • Flow cell QV-Flow PMMA OTG made of acrylic glass with needle valve and digital sample flow meter on mounting angle made of stainless steel.
  • Swansensor Hydrogen with platinum anode and integrated NT5k temperature sensor.
  • Faraday electrode for the automatic or manual verification by electrochemically generated hydrogen concentration in the ppb range.
Dissolved Hydrogen Analyzer

Specifications:

  • Measuring range: 0.01 ppb to 800 ppb H2 (at 25°C, 1013hPa) or 0 – 50% saturation.
  • Automatic air pressure compensation.
  • Automatic temperature compensation.
  • Simultaneous measurement of dissolved hydrogen, sample temperature and sample flow.
  • Large backlit LC display showing measuring value, sample temperature, sample flow and operating status.
  • Easy user menus in English, German, French and Spanish.
  • All parameters are easily programmed using the keypad.
  • Two current outputs (0/4 – 20 mA) for measured signals (3rd output optional).
  • Data logging of major process events and calibration data.

Detailed Specification can be found on Page 2 of this Data Sheet.

Application Note: Measuring Dissolved Hydrogen in Water Steam Cycle to Predict and Prevent Potential Corrosion


Every year, corrosion costs the electric utility industry billions of dollars. International guidelines are available for water chemistry control to minimize corrosion. Parameters such as pH, oxygen, iron, hydrogen and others are directly related to corrosion control and used for monitoring corrosion. International technical organizations and power plant chemists are working diligently to find a
suitable method to provide real-time corrosion trend monitoring in their process during commissioning and normal operation.

Hydrogen monitoring in this case is becoming important in corrosion monitoring for water steam cycle [1, 2, 3]. Corrosion occurs in the presence of water contact with iron at high temperature. According to the Schikorr reaction (Eq. 1), hydrogen is released as a by-product during the formation of the magnetite and hematite layer in the power plant. Therefore its concentration is a direct measure of the rate of corrosion.

  3Fe + 4H2O → Fe3O4 + 4H2    (Eq. 1)

During commissioning of a new power plant, commissioning engineers need the formation of uniform iron oxides as a protective layer on the surface of the metallurgy to limit further corrosion of the steel. However, some iron oxides are disrupted and formed again during operation. The disruption and formation of the iron oxides layer will release hydrogen gas. Even though other possible sources of hydrogen exist, measuring dissolved hydrogen concentration in the process will provide valuable indication of an active corrosion rate in the system.

Various tests and research have been carried out to identify suitable sampling points for a representative sample. Hydrogen concentration is commonly measured in the steam or feedwater[4] to ensure that corrosion rates are kept at an acceptable level.

Guidelines for hydrogen levels are not well defined and may vary from plant to plant. Available research indicates hydrogen levels occur at a few ppb (part per billion) during normal operation and as much as several hundred ppb during commissioning. However, hydrogen values greater than 10ppb-50ppb under normal working condition may be an indication of permanent damage to the boiler.

Graph 1 (below) shows typical hydrogen measurement in a once-through superheated steam boiler. The power plant is using oxygen treatment with ammonium as an alkalizing agent in the water steam cycle. Dissolved hydrogen measurement tracking in superheated steam provides an indication of the corrosion trend in the boiler. This information is very useful to plant chemists for corrosion monitoring and control. The plant chemist could take the necessary action to mitigate corrosion. Information in the graph indicates that the corrosion rate is under control.

Hydrogen measurement in once through superheated steam graph

Graph 2 (below) shows hydrogen measurement in feedwater (economizer inlet). The graph indicates increase of dissolved hydrogen in feedwater at various times. This indirectly represents increasing of corrosion rate in the feedwater system. The dissolved hydrogen increase appears before corrosion is excessive. Corrective action was taken to reduce and control corrosion in feedwater.

Hydrogen Measurement in Feedwater

Accessories

  • A-75.400.000 QS-Monitor AMI INSPECTOR Hydrogen.
  • A-81.420.020 AMI Option; Profibus- / Modbus Interface.
  • A-81.420.042 AMI Option; USB Interface.
  • A-81.420.050 AMI Option; 3rd signal output.
  • A-81.420.060 AMI Option; HART Interface.
  • A-88.224.220 Communication cable, AMI to PC, 2 m.
  • V-9700910 Service Hydrogen sensor including calibration and labeling.

Dissolved Hydrogen Analyzer Spare parts

  • A-87.260.001 Swansensor Hydrogen.
  • A-88.155.X20 Sensor cable for Sensors with M16 plug.
  • A-89.811.060 Set of fuses for AMI.
  • 2 Relay outputs Two potential-free contacts program-able as limit switches for measuring values, controllers or timer with automatic hold function. Rated load: 1A / 250 VAC
  • 2 Signal outputs (3rd as option)Two programmable signal outputs for measured values (freely scalable, linear or bi-linear) or as continuous control out-put (control parameters programmable) as current source. 3rd signal output selectable as current source or current sink. Current loop: 0/4 – 20 mA Maximum burden: 510 Ω
  • Optional Profibus- / Modbus Interface
  • Optional HART Interface
  • Optional USB Interface
  • Optional Third 0/4 – 20  mA Output

All Swan Analyzers are CSA Cirtified at our premises before shipping.