SO₃ Monitor

Sulphur trioxide (SO₃) is formed as a by-pruduct during the combustion of fossil fuels for power generation and is also used or produced in many industrial processes. At temperatures below about 2000C it combines with water vapour to form sulphuric acid which has deleterious effects on plant surfaces and on the environment.

In power generation SO₃ measurements provide data to allow the operator to burn fuel in the most efficient way to minimize corrosion of the plant and limit acid discharges tot the environment. Monitoring of SO₃ is also important where it is formed as a by-product, e.g. in DeNOx systems.

The SO₃ monitor has been designed to meet a wide range of measuring requirements. The instrument is portable and suitable for long and short term measurements.

The unit is auto calibrating in a user defined  cycle.

An optional RS232 connector allows to record the measurements on a laptop.

Operating Principle

The SO₃ or H2SO₄ in the gas sample is absorbed as sulphate ions (SO₄^2-) in an aqueous solution of propan-2-ol in water. The solution is passed through a bed of barium chloranilate.
The acid chloranilate ions are measured in a continuous flow photometer. By maintaining a constant ratio of flow rates for the gas and the propan-2-ol absorbing solution, the concentration of acid chloranilate ions can be directly related to the sulphate ion concentration in the absorbing solution, and hence the SO₃ concentration in the gas.

Technical Specification

Range:                                   0 - 200 ppm
Accuracy:                             1 5% of reading (in calibrated range)
Lag time:                               Approx. 60 seconds
Response (90% FSD):        Approx. 120 seconds (depending on umbilical length)
Solution consumption:       0,25  2 cm³/h (adjustable as required)
Ambient temperature:         0  400C
Module dimensions:
                Analysis:              19 unit, 6U high, 500 mm deep (27 kg)
                Control:                 19 unit, 4U high, 400 mm deep (13 kg)
Power requirements:           230V 50/60 Hz or 110V 50/60 Hz, 350 W
Probe length:                       1 m, 1,2 m, 1,5 m, 2m
Signal Output:                     4.. 20 mA output for recorder
                                               RS232 to PC connector on request

Documentation

Brochure SO3 Monitor