Galvanic Applied Sciences 943-TGS-CE, Руководство по эксплуатации

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Revision 5 17 August 2021
Incoming sample gas is filtered to 60 micron and drawn through the measurement cell by the
aspirator. The measurement cell exposes a known length of sample to UV radiation for
spectroscopic analysis. The aspirator is integral to the measurement cell and uses instrument
air (or other inert gas) as the aspirator drive gas. The analyzer turns on the aspirator drive media
only when no analyzer faults are detected. In the event of a fault condition, the analyzer
automatically purges the entire sample handling system with instrument air.
Analyzer zeroing is accomplished by introducing higher pressure instrument air (or other inert
gas) upstream of the measurement cell. The zero gas flushes the entire sample handling system
(probe to vent) and allows readings to be taken through the measurement cell when no
absorbing species are present. To the sample system, zeroing and back purging are the same
thing. The default state (power ‘off’) of the analyzer is to have the sample system in the back
purge
mode. Valving is provided for isolating the sample system components from the process
stream. A provision is included in the oven plumbing for the steam purging of the sample probe
after a plant shut-down or turn-around, or in the event of plugging of the sample probe, should
it be required.
The interior of the oven cabinet maintains all components exposed to the tail gas sample at a
controlled temperature that is higher than the sulfur dew point value. The oven and sample
probe are mounted to an interface plate, which in turn is directly mounted to the steam heated
process duct sample nozzle (typically a 2-inch, 150 pound pipe flange configuration). Electrical
heat is applied to the measurement cell to achieve precise temperature control of the entire
oven cabinet interior, which contains the measurement cell block and the associated sample
handling system tubing and valves.
1.5 System Operating Control
The analyzer system operation is controlled by a dedicated data acquisition system which
provides supervisory control of all analyzer inputs and outputs, performs all calculations, and
provides the user interface.
The system includes an onboard computer system which provides a graphic display of key
system control parameters and their status, a digital display of the instantaneous value of the
Air Demand, H
2
S, SO
2
, and COS, and historical graphic displays of the Air Demand, H
2
S and
SO
2
. The entire control computer system, consisting of a Control Board and a Display Board ,
is mounted on the door of the control cabinet. Control cabinet access is not required for viewing
or operation.
The measurement of carbonyl sulfide (CS
2
) is an optional measurement. Analyzers
which have not been ordered with this option cannot measure CS
2
.
Four loop-powered 4 – 20 mA
analog outputs
are provided for the output of analyzer
measurement parameters. These four analog outputs are user-configurable for the output
parameter and range. Additionally, four solid-state relay outputs are provided for the output of
system status data. An RS485 serial port is also provided which can be used for available for
Modbus
communication. Two Ethernet ports are provided for use either for Modbus TCP/IP
communication OR for connection of a computer for GUI access. Aside from the Ethernet ports,
which are located on the control board, all inputs and outputs are found on the analyzer’s Input
/ Output Board inside the control cabinet.