While many elements can be quantified by general purpose atomic spectroscopy instruments, there are a number of applications that have created niches for specific techniques dedicated to particular elements of interest. One important species of elemental analyzers is carbon/sulfur analyzers. Carbon and sulfur can be critical elements to measure in a variety of matrices. A number of instruments make use of combustion combined with one or more measurement techniques to quantify these elements.

The combustion process is relatively simple: solid samples are introduced into a furnace in order to liberate all of the carbon and sulfur in the sample in the form of carbon dioxide and sulfur dioxide gases. Depending on the application, the furnace may heat the sample to temperatures reaching 2000 °C or higher. After the evolved gases are treated and cleaned to eliminate interferences, they are introduced into the measurement cell. IR spectroscopy is the most common final measurement method, but other possibilities exist, and are sometimes used in concert with the IR detector. Typically, carbon/sulfur analyzers can be configured to measure either or both carbon and sulfur, depending on the specific application.

While just about any sample could conceivably be analyzed in this fashion, applications are fairly limited to a few types of industrial samples. Steel analysis is probably the most important, as carbon content is critical to determining the final properties of steel, and sulfur is typically considered an impurity that must be controlled. However, some types of steel contain small amounts of sulfur in order to make them easier to machine. Similarly, other metallic alloys can be measured as well as the raw ores from which metals are refined.

Another major source of applications is the energy industry, particularly for coke and coal testing, but also for analysis oil and other petroleum derivatives. Carbon content is important for judging the grades of various fuels, while sulfur content is subject to air quality or other environmental regulations. Environmental regulations are also the source of applications in measuring soils and other industrial wastes. A number of applications also exist for analyzing cement, rubber, glass, ceramics, and even plant or agricultural samples.

As with most elemental analyzers, the competitive situation is more limited than for the general purpose atomic spectroscopy market. LECO is the top vendor in the marketplace—as it is for most types of elemental analysis. LECO offers specialized systems for either organic or inorganic sample types. Eltra is the next largest vendor, followed by HORIBA, which recently released the EMIA-Pro Carbon/Sulfur Analyzer (see IBO 3/31/16). Other vendors include Angstrom Advanced, Bruker, Jung Instruments, LabFit, Qualitest and Torontech. The total market size for these products was about $40 million in 2015.

Carbon/Sulfur Combustion Analyzers at a Glance:

Leading Suppliers

• LECO

• Eltra

• HORIBA

Largest Markets

• Metals

• Energy

• Oil and Gas

Instrument Cost

• $40,000–$80,000