Mercury Process Analyzer PA-2
Continuous On-Line Detection of Mercury in Water and Aqueous Solutions
- Fully automated mercury detection system
- Easy menu-driven operation
- Display of real-time signal reading
- Proven and reliable detection method: UV absorption
- Mercury Measuring ranges from 0.01 ppb to 100 ppm
- High flexibility of sample pretreatment procedure
- Right for complex sample compositions
- Low reagent consumption
- Corrosion-protected construction
- Automatic self diagnosis system for reliable
operation
On-line Process Control of Mercury with the PA-2
The mercury process analyzer PA-2 is
used for continuous monitoring of mercury concentrations
in industrial processes. Applications include effluent
and quality control in chlorine-alkali plants,
monitoring of scrubber water of waste incinerators and
power plants, control of industrial sewage and
purification plants, quality control of sulfuric acid,
drinking water. Special version also for concentrated
caustic solutions (NaOH, KOH)
Online Measurement of mercury in concentrated (50%)
caustic soda with the PA-2 (left), the sample passes a
specially designed dilution system (right). Location:
chlor-alkali plant.
Flexibility in Sample Digestion
In practice mercury analysis sample matrices very often show different and variable compositions. Depending on the chemical process the forms of mercury differ: elementary, ionic, dissolved as a salt, as an organic compound or as insoluble sulfide. The PA-2 offers a variety of sample pretreatment procedures to allow highly precise determination of total mercury in all these samples, with the results from the PA-2 showing very good correlations with standard laboratory analyses. High flexibility is achieved by the modular structure of the sample pretreatment module. This allows the user to choose from the following digestion methods:
- Sample pre-oxidation with hydrochloric acid + potassium permanganate
- Sample pre-oxidation with sulfuric acid + potassium permanganate
- Sample pre-oxidation with hydrochloric acid + sodiumchlorate
- Sample pre-oxidation with Fentonīs reagent
The integrated heated reaction module allows accelerated sample digestion at increased temperatures. The duration of reactions can be adapted to the need of your application by employing reaction coils of different lengths.
Proven Mercury Measurement Principle
The detection of mercury contained in the sample
occurs in an optical cell made of fused silica (Suprasil). In a
first step mercury is reduced to the elementary state by means of
tin(II)chloride or NaBH4. Subsequently mercury is stripped from the
aqueous phase with an air stream and carried
into the optical cell. Here the UV absorption measurement is
conducted at a wavelength of 253,7 nm. This analytical technique
called cold vapor atomic absorption spectroscopy (CVAAS)
shows extreme sensitivity and selectivity. It has been reliable and
proven for many years. In contrast to the occasionally recommended
atomic fluorescence method the analytical technique utilized by the
PA-2 is extremely low in interference and does not require an
amalgamation step nor expensive noble
gas as a carrier.
Industrial Grade Design
To provide optimum protection against corrosive environments all parts of the PA-2 Mercury Analyzer are enclosed in an industrial-grade cabinet made of fiber glass, reinforced polyester (protection class IP 66; NEMA 4X; etc.). The electronic circuitry is shielded from the wet chemical section by a chemically resistant wall.
(coal fired power station)
(chlor-alkali plant, Germany)
PA-2 for continuous monitoring
PA-2 reading the Hg concentrations in effluents of Hg in scrubber water.
Continuous and Interval Operation
The PA-2 analyzer is controlled by a built-in
computer and operates fully automatic. The continuous measuring mode
can be switched over to a periodic measuring mode (for example 10
minutes of measurement every hour). Auto-Cal. Check: periodically
the instrument switches from the sample stream to a calibration
solution to check any deviation from the reference value. A status
signal is generated if the value measured is out of range.
Auto-Zero: the zero line of the analyzer is adjusted automatically
after a preset period of time. Self-Cleaning: Precipitations like
manganese dioxide
are dissolved by an automatic rinse step which makes manual cleaning
superfluous.
Easy to Operate
Display and Output of Mercury Measurements
The analytical results are continuously displayed on an LCD in micrograms per liter and as absorption units. A linear electrical signal (4 ... 20 mA) is also output and can be connected to a recorder or to the analog input of a data acquisition system.
Automatic Self Diagnosis System
The PA-2 is equipped with sensors to detect malfunctions of the system and triggers an alarm for the operator. The following functions/malfunctions are checked and indicated:
- Reagent flow
- Sample flow
- Stripping air flow
- Leakage of fluids
- Photometer lamp
- Calibration
These features permit reliable unattended operation. Malfunctions are reported to the user both optically and via a status signal.
Automatic Self Diagnosis System
The PA-2 is not a laboratory analyzer simply
converted for process applications but has especially been designed
for operation under harsh industrial conditions. The number of parts
subject to wear has been
minimized and particularly durable components have been chosen for
use in critical locations. This results in extended maintenance
intervals. The stripping unit is based on an aerosol-free principle
and the need for cleaning the optical cell is particularly low.
Communication with External Computers
The following data is available at the serial RS 232 interface: Actual mercury concentration Status (Ready - Maintenance - Malfunction) Thanks to the bidirectional interface, operational functions like "Zero Adjustment", "Calibration Check" and "Start Measurement" can be triggered externally
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PA-2 Mercury Process Analyzer Technical Specifications
- Measuring Principal: UV-Absorption
- Wavelength: 253.7 nm
- UV Source: electrodeless low-pressure mercury lamp
- Stabilization Method: reference beam and thermal
- Measuring Range: lowest range: 0...1 ĩg/L, highest range: 0...100 mg/l
- Response Time (99% signal): approx. 1 minute
- Alarm: 3 levels programmable
- Carrier Gas: Air, approx. 30 L/h, 1 bar
- Pump for liquids: Multichannel peristaltic pump
- Reduction reagent: Tin-II-chloride or alternatively sodiumhydroborate
- Reagent consumption: approx. 3 L / week for each reagent
- Sample digestion: HCl or H2SO4, KMnO4 or H2O2 or Fentonīs Reagent or Na-chlorate(depending on sample composition)
- Liquid gas separation: Aerosol-free principle
- Input device: Waterproof membrane keypad
- Output for concentrations: 4...20 mA; RS 232 bidirectional
- Output for status: Operational - Service - Malfunction, according to NAMUR 64 recommendations
- Housing: Fiber-glass reinforced polyester, for use in highly corrosive environment - Reagent storage cabinet made of chemically resistant plastic material
- Protection glass: IP 66 (EN 60529/ NEMA 3; 3R; 4; 4X; 12; 13)
- Power Supply: 230 V / 50/60 Hz (110... 120V / 50/60 Hz optional)
- Power Consumption: 250 W max.
- Measurement Display: graphical LC display with background illumination
- Signal Outputs: 4...20 mA; RS 232 for PC or printer
- Air Consumption: Instrument air, approx. 30 l / h, 1 - 6 bar (14 - 85 psi)
- Weight: 110 Lbs
- Dimensions:
30.6" wide
x 24.1" High x 13" deep
As a leading supplier of high precision analytical equipment, we strive at all times to offer top quality solutions. Our products are manufactured according to the ISO 9001 quality regulations.