RHADOX^(TM) Analysers

The Measuring System for the Determination of Air Demand and
Wobbe-Index in Combustion Gases -

Extendable for the Density Measurement and Determination of the Calorific Value

Off-gases as energy source

Application areas

System features

The measuring procedure

The system components

Determination of Air Demand, Wobbe-Index and Calorific Value

The density measurement

Factory application

Technical data

Product sheet for the RHADOX systems
The Measuring Procedure for RHADOX systems
Applications with the RHADOX-systems

Back to the product program

Off-gases as energy source

As a cost saving alternative to natural gas commonly used in industrial combustion processes, more and more gases are employed which are accumulated at other processes: in chemical plants and refineries, in furnaceses and coke ovens, in land fills or in bio-processes.
However the composition of these exhaust gases varies strongly due to their generating process.
The complete and safe combustion of these gases by controlling the Air Demand is strongly needed; controlling the energy supply via the Wobbe-Index is an economical necessity as well as minimizing the emissions is definitely desirable.
Thus the reliable and continous measurement of the Air Demand and the Wobbe-Index in the combustion gas is imperative to adjust the combustion process to changing gas qualities and operating conditions.

Application areas

• Off-gases from furnaces
• Off-gases from chemical plants
• Off-gases from refineries
• Off-gases from sewage digesters and bio-gas plants
• Feed forward combustion control in all Natural Gas-fired boilers and industrial furnaces
• In facilities for power generation and in the chemical and petro-chemical production
• At the generation of synthetical gases, also with very low Wobbe-Index
• The gas flame as a tool:
  assuring quality in the glass industry

System features

• Due to its measuring priniple the RHADOX-system ist insensitive to temperature deviations thus neither thermostating the instument´s housing nor a specific ´´calorimeter room´are required.
• The measurement is independent of deviatioins of the air pressure or of the sample gas pressure.
• The instrument features the flamelöess oxidation of the sample gas; hence also strong gas quality deviations or low Calorific Values will be definitely registered.
• The measuring system reacts very fast. Response times (T90-times) of 10-12 seconds for Air Demand and Wobbe-Index are common, the integrated gravity measurment and the determinati0on of the Calorific Value take aubout 25 seconds.
• The basic RHADOX measuring system for Air Demand and Wobbe-Index can be extend for the measurment of the Speicific Gravity and the Calorific Value.
• For the Oxygen measurement a sturdy O2-sensor is employed.
• The RADOX system is suitable for continuous operation in industrial processes.

The measuring procedure for RHADOX 1000 and RHADOX 3000 -
Air Demand and Wobbe-Index

• Sample gas and air are heated and pressurised until identical temperature Tand pressure p.
  The numbers of T and p are unimportant to this procedure.
• Sample gas and are mixed at a controlled rate.*)
• Catalytic oxidation of the gas mixture.*)
• Measuring the residual Oxygen.
• Air Demand and Wobbe-Index are determined from the calibration data.
  

• The Specific Gravity is measured applying the method of Bernoulli.**)
• The Calorific Value is determined from the Specific Gravity and the Wobbe-Index.
  

*) The mixing chamber and the procedure for the catalytic oxidation to determine Wobbe-Index
and Air Demand are covered by European patents.
**) The measuring procedure to determine the Specific Gravity is covered by European patent.

The RHADOX systems

Primarily the RHADOX measuring systems are designed for the determination of the Stöchiometric Air Demand as well as for the energy transport to the burner i.e. the Wobbe-Index. Both numers are needed to assure the complete and safe combustion of the sample gas: RHADOX 1000.
The RHADOX 1000 systems can be extended for the measurement of the Specific Gravity drel of the sample gas to determine its Calorific Value: RHADOX 3000.
For specific applications a PTB-approved RHADOX system for legal (fiscal) metering can be delivered (RHDOX 2000, PTP certificate 3.14-06703-97).

(C) AMS GmbH 8.0/2007 Subject to technical modifications.   Text, drawings and layout: Analytic Journal

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