Method of Detection

Using a unique thermocatalytic converter, all oxidized mercury compounds are converted to elemental Mercury within the probe. This stream is then passed through a gold trap amalgamation unit where only mercury is absorbed to remove interference from other compounds. Subsequently, the mercury is desorbed from the gold trap and measured in a UV atomic absorption photometer at 253.7 nm

 

No Interference, No Cross Sensitivities

SO2, NOx  and other gaseous organic compounds (e.g. VOCs) cause a dramatic disturbance in the measuring signal since they also absorb at a wavelength of 253.7 nm. This results in spurious signals associated with traditional mercury analyzers. However in the Hg-CEM we use a Gold Trap Amalgamation unit and by selectively absorbing and desorbing Mercury we can eliminate interference from other compounds


Selection of Optimum Materials of Construction to Minimize Memory and Hystersis Effects

The choice of the materials of construction is crucial in the analysis of mercury. Thus we minimize the contact with metallic surfaces. In a few instances where it is strictly unavoidable, heated high-grade stainless steel is used. All fittings and tubing comprise of Teflon, Tygon, Quartz and glass. All surfaces coming in contact with ionic mercury are held at elevated temperatures.


Excellent Price to Performance Ration, Low Maintenance and Operating Costs

For the Hg-CEM we have put emphasis on a cleanly designed structure with minimum maintenance requirements. The design is modular so that individual components can be exchanged easily. The operating costs for the total life cycle of the instrument are extremely low.


Easy to Service and Repair

The entire system is functionally controlled by a microprocessor. All input is made through a water-resistant front panel keyboard with user-programmable keys (“soft keys”). A large TFT color screen vividly displays all system variables and measured values. The system components are used in a “swing design” compartment and can be very easily accessed. The most important components are housed in two 19” rack-mounted units each 3 units high. Other components can be accessed from the back plate of the housing.


Automatic Operation with Minimum Supervision and Remote Monitoring

The Hg-CEM executes an automatic zero point and a reference point procedure at preset intervals. Important process variables like flow rate, temperature and instrument drift are continuously monitored. In case of excessive deviations from set values, a status signal is activated to alarm the operator.


Sampling System (Probe and Heated Line)

The sample probe extracts 2 to 3 liters per minute and transports it through a heated sampling line at 200 ºC.  In order to prevent loss of mercury in the sampling line it is recommended that the line not exceed 150 feet.


Thermocatalytic Converter

This thermal catalyst causes the reduction of ionic mercury compounds to elemental mercury vapor. The thermocatalytic converter unit is integrated within the sampling probe and is easily accessible for maintenance. After the catalytic converter, Mercury exists only in the elemental form and hence drastically reducing MEMORY effects.


Gold Trap Amalgamation Unit

This amalgamation unit consists of an integrated valve assembly, a gold trap and a calibration source for elemental mercury vapor. The valve assembly can be switched to a “continuous mode operation” in case of high mercury concentrations.


UV Photometer

The UV Photometer used by the Hg-CEM system is a time tested instrument that has been toughened and field-proven. It consists of a fixed wavelength atomic absorption spectrometer at 253.7 nm wavelength. The photometer has a reference beam for lamp control and an electrode-less low-pressure lamp with long service life (>20000 hours).