Aromatics moleculeThe BA-BTX is part of the BAGGI BASE® Instruments Series. It provides accurate on-line measurements of Benzene, Toluene and Heavy Aromatics (like Xylene) concentrations in Solvents. This instrument is an application of quantitative Ultraviolet/Visible spectroscopy analysis, with high wavelength resolution. The measurement technique relies on the Beer-Lambert law. This one is a relationship that relates the absorption of electromagnetic waves to the properties of the material through which the waves are travelling.

The material from the process (solvent) is introduced in a sample cell of specific optical path length.

The UV energy is transmitted to the cell via an optical fiber cable, it passes through the cell space and the residual energy is transmitted to the UV sensor by a second optical fiber. The UV sensor sends the collected data to a computer that calculates the exact concentration of Benzene Toluene & Heavy Aromatics, and drives the outputs.




The computer evaluates the difference between the sample spectrum and the solvent reference spectrum making a comparison of the energy absorbed at each wavelength. The connection from the core analyzer to the sample probe is made by two Stainless Steel armoured fiber optics cables.

According to the length of the sample cell, the measurement ranges in Parts Per Million by Weight (PPMW) are the following:


Range 1

Range 2

Range 3


0.9 to 100

2.0 to 250

9.0 to 1000


2.0 to 175

4.9 to 440

20 to 1750

Heavy Aromatics

0.32 to 28

0.8 to 71

3.5 to 280

Accuracy: ± 1 % of the Full Scale (any compound range)

Response time: 90 % of the Final Value in 10 sec. (typical)

Benzene spectrumThe computer offers an easy-to-use Graphical User Interface (GUI). The screen shot, displayed here, shows a Benzene concentration measurement together with the related Absorbance spectrum (the spectrum of the UV energy absorbed by the material, that is a function of the compounds).

The measurement results are time-stamped and saved in csv format on non volatile memory. The tabular data can then be dumped on a USB key, accessed by a LAN/WAN or printed.

The real time results are transmitted by means of dedicated 4…20 mA current loops, while the alarms are transmitted via dedicated relay contacts.

The menu driven interface allows the Operator to carry out the calibration procedure and to know the maintenance status.

The software is password protected and can be updated easily through a USB key.

In addition to the BTX application (Benzene, Toluene and Heavy Aromatics concentration measurement), other software packages are available:

· BA-BTTS: for on-line measurement of Benzene, Benzene + Toluene and Total Aromatics concentrations in solvents.

· BA-TOAS: for on-line measurement of Total Aromatics concentration in solvents.

Furthermore, the computer can be delivered in ATEX certified versions:Analyzer benzene

· II 2 G Ex px II T6

· II 3 G Ex pz II T6

The picture shows a BA-BTX analyzer in an ATEX certified version, contained within a 316L Stainless Steel enclosure provided with a protective air purge system (connected to the plant instrument air). The sample cell is visible underneath.

Please follow this link for more information.

The system comes with any accessories that may be needed:

· Sample cooler

· Pump

· Pressure regulator

· Flowmeter

· Liquid-liquid filter to separate humidity from solvent

· ATEX certified junction boxes


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