MERCURY VAPOUR GENERATOR
Mercury Vapour Generators are used to produce a known concentration of mercury.
This gas is then for a range of applications, such as
- Analyser calibration
- System integrity test
- Sampling system testing for losses/drift
- Spike testing of analyer systems
- Spiking process for Catalyst removal efficiency testing
The wide range of calibrations is supported by the P S Analytcail 10.534 and 10.536 series of calibration gas generators.
Variants include changes to
- Control Mode - manual or computer control
- Reservoir Type - Hg bed or Permeation device
- Flow and Temperature limits - Flow rate and oven temperature variations.
Method of Control
The PSA 10.534 series of calibration gas generators are manually controlled, whilst the PSA 10.536 series offers full computer control via MODBUS RTU.
With the PSA 10.534 series, the CavKitCalc software is used to calculate the flow rate and temperature settings required to generate the desired mercury concentration. The temperature and flow rates are then selected using the controls on the front of the instrument.
The PSA 10.536 series is computer controlled (via MODBUS RTU) using the CavKitCalc or the PSA OnLine software. The software packages are used to calculate the settings required to generate the desired mercury concentration and to automatically implement the settings. With PSA OnLine, the concentration can be automatically varied for different tests or multipoint calibrations and the gas flow can be stopped when not required.
The PSA 10.536 series instruments are typically used within a complete PSA mercury CEM where the automatic features allow a wide array of tests to be performed with minimal user intervention.
The PSA 10.534 series instruments are typically used in more manual systems where standalone operation and direct control is required.
Reservoir Type
For the majority of applications, e.g. continuous emission monitors for stack gas and removal technology testing the levels required are in the microgram per cubic metre (µg m-3) range supported by either the standard (no part number suffix) or High-Level (part number suffixed “H”) Mercury Vapour Generators featuring a mercury reservoir are used.
For low level applications such as air monitoring where nanogram per cubic metre cubed (ng m-3) concentrations are required, the Low-Level Mercury Vapour Generators (part number suffixed “L”) featuring mercury permeation tubes are employed.
The standard and high-level options include a mercury reservoir. These units operate on the principle of dilution a saturated source of mercury at a known temperature. A low flow rate is passed across the mercury reservoir ensuring that the gas becomes saturated with mercury. The mercury-saturated gas is then diluted into the concentration range of interest. The flow rates are controlled using two mass flow controllers. The unit also generates a Hg free zero span so that blank measurements can be performed. The Hg concentration can be adjusted by altering the temperature of the oven or by adjusting the reservoir or dilution flows.
The low-level options include a permeation tube in place of the mercury reservoir. With this option, the permeation rate is first established at the temperature of interest and the concentration then changed by adjusting of the dilution flow rate. Different concentration ranges can also be achieved by use of permeation tubes with different permeation rates.
Flow Rates/Temperature Ranges
The last option is the flow rate range of the mass flow controllers (MFCs) and the available range of the oven temperature.
The standard and low-level options feature 0-20 ml min-1 reservoir/permeation flow rate range and a reservoir/permeation tube temperature range of 35-60°C to permit good control over the lower flow rate ranges.
The high-level options feature hotter ovens to generate higher saturated mercury concentrations from the oven and a 0-30 ml min-1 reservoir flow rate to further increase the maximum mercury flow available.
Table of Models:
Model |
10.534/10.536 |
10.534H/10.534H |
10.536L/10.534L |
MFC 1 |
0-20 ml min-1 |
0 - 30 ml min-1 |
0-20 ml min-1 |
MFC 2 |
0-20 l min-1 |
0 - 20 l min-1 |
0-20 l min-1 |
Oven |
35 - 60ºC |
35 - 100ºC |
0-60ºC |
Hg Source |
reservoir |
reservoir |
Permeation Tube |
Concentration Range |
1.7 - 3000 Hg M3 |
13 µg m-3 - 13 mg m-3* |
3 - 60 ng m-3 |
* 13 mg m-3 calibration gasis saturated at room temperature, with appropriate heat tracing higher temperatures are possible.
To discuss any particular requirements and/or for more detailed information on the above products please complete the Information Request Form.
