In the chemical industry and in thermal engineering processes

precise measurements of trace Oxygen as well as of vol-% Oxygen in gases with combustible components

is a frequent analysing challenge.
For this particular purpose the well known Zirkonia sensors are not suitable.

The analyser PAT 3120 is best suitable for quick and . This has a favourable effect on controlling wide concentration ranges typical for heat treatment, welding and inertisation
Measuring vol-% Oxygen, as well as in the case of a short-time exposure to ambient air, the ppm-sensor will be protected against damage caused from high Oxygen contents; there is no longer waiting time for purging, less than 25 ppm Oxygen can be measured immediately afterwards.

The PAT 3120 is fully process adaptable. A microprocessor controlls the electronics and the display, calibration and maintanance sequences are menu operated

.

Oxygen analyser PAT 3120
for measurents in %- and ppm-range
even in combustible components

To the product sheet

The wide range of applications of ZrO₂-probes for the measurement of Oxygen in flue gases is well known and widely accepted.
An additional requirement however

is the simultaneous measurement of combustible gases, mainly Carbonmonoxide,

but also Hydrogen or unburned Hydrocarbons in order to determine the optimum of combustion or process efficiency.
AMS offers a

fast, versatile and cost effective instrument for direct in-line measurement,

using a newly developed dual-sensor for measuring simultaneously O₂ and Combustibles (measured as CO-Equivalent COe).
A EEx-approved version for zone 1 is also available
(ATEX II 2G EEx d IIB+H2 T3).

Further informations:
e-mail info@ams-dielheim.com

.

To the product sheet AMS 3211-1500

Off-gases, left over at refinery or other industrial processes e.g. coke ovens, are more and more in common usage as a source of energy, for environmental reasons and as a cost saving alternative to natural gas fuelling.
However the composition of these exhaust gases varies strongly due to their generating process.

Therefore the reliable and continuous measurement of the Air Demand and the Wobbe Index in the gas is needed to adjust the combustion process to changing gas qualities and operating conditions.

The measuring system Rhadox™ is designed particularely to meet these demands:

■ fast reaction time below 10 seconds,
T₉₀-time below 25 seconds are feasible.

■ no temperature controlled equipment installation is required since the technical data of the Rhadox™ maintained also for strong changes of the ambient temperature.

■ a field unit (IP56) and EEx-approved version for zone 2 are available

Sources for flare gases

• refineries, bio-gas plants
• industrial furnaces, converter or coke ovens

Applications

• production of blended gas with prescribed quality
• processes where the gas composition has an important impact on the flame and on the gas quality

The purpose

Making use of the energy content of the flare gases to generate electric energy or process heat.

The measuring task

Fast and continuous measurement of the Air Demand and of the Wobbe Index of the probe gas.

The measuring principle

The probe gas is completly oxidised in air surplus, the residual Oxygen is a reliable measure for the Air Demand of the probe gas whwn oxidised.
From the calibration curve Air Demand vs. Wobbe Index the latter can be extracted. In most cases the relationship Air Demand - Wobbe Index is linear. The identification of the calibration curve is a major part of the AMS application lab.

From the Wobbe Index the Calorific Value can be determined if the Specific Gravity of the probe gas is known.

Problem 1

Determination of the Specific Gravity of the probe gas online and continuously during the running process.

Problem 2

The mixture of the probe gas with the combustion air for the complete oxidisation must be constant and reproducible.

But in reality off-gases from plant processes often exhibit broad variations in their composition, sometimes soaring or plunging the Wobbe Index within seconds from MJ/m³to 100 MJ/m³. This corresponds to the variation from low calorifc gas to Propane.

Herewith the determination of the Wobbe Index is based on the measuring of just one single parameter, the residual Oxygen concentration, after the oxidation of the probe gas.

Parallel to the Wobbe Index determination the Specific Gravity of the probe gas is determined from the measurement of the Oxygen concentration in the already mixed (with combustion air) but not yet burned probe gas.

The Rhadox™ - analysing system for
Ex-zone 2 and field unit implemented

Calibration curve Air Demand versus Wobbe Index

How talculate the Calorific Value

To the product sheet

Gas Analysis with the Thermal Conductivity Analyser FTTCA 1100

The classic gas analysis via thermal conductivity, well known as a reliable and simple measuring technique since the thirties, is used in industrial processes to measure components in binary or (quasi~)binary gas mixtures. Particularily Hydrogen, Helium and Nitrogen being optical inactive making an IR-sensor obsolet, are measured with a TC-sensor. If the gas mixture contains more than two components an additional instrument, mostly an IR-analyser, must be employed to detect the second component.

Now the new FTTCA (Fourier-Transformed Thermal Conductivity Analysis)-technique makes possible the simultaneaus measurement of all three components in a multi-component gas mixture. On the one hand the FTTCA-method employs a physical effect known but not often used in process analytics and on the other hand FTTCA is feasible through the availibility of todays newly developed miniaturized thermal-conductivity sensors only. The physical effect comes from the different temperature dependence of the thermal conductivity of the different gas components. Hence the recording of a multi-dimensional concentration field, consequently followed by a fast Fourier-transformation, enables the analysis of three or four component gas mixtures.

• Bio-gases (fermenter-gases) iin the three component mixture N₂-CO₂-CH₄, up to now requiring anadditional measuring system, in most cases an IR-analyser.
• Mixtures of N₂-H₂-CO₂ frequently used in the chemical industry
• .Mixtures of N₂-He-H₂, which could not be analysed employing the classic TC-technique (see diagram below).

Multi-Component-Gasanalysis
with
Fourier-Transformed Thermal Conductivity Analyser FTTCA 1100
EEx-version

To the product sheet