9900 vs. 9933 for Hydrogen Sulfide Measurement
Smart Analyzer Selection Is About Recognizing Total Value—Not Simply Choosing the Highest or Lowest Priced Analyzer
When end users need an online hydrogen sulfide (H₂S) analyzer, they often question the differences between a 9900 and a 9933.
The 9900 is a proven, versatile gas analyzer capable of measuring ppm levels of H2S. With less standard analytical hardware, the 9900 has a lower initial investment than the 9933. In some H₂S applications, the 9900 can indeed be the right solution.
The 9933 is also a proven, versatile gas analyzer capable of measuring ppm levels of H2S. But it can also measure ppm levels of carbonyl sulfide (COS) and methyl mercaptan (MeSH) and has integrated hardware to remove interfering components from the measurement process. The 9933 is a fit for purpose analyzer, designed to accurately measure sulfur components in natural gas and other hydrocarbon streams. With the additional measurement capabilities, the 9933 has a higher investment vs. the 9900.
Ultimately, when measuring H₂S in natural gas and hydrocarbon streams, the decision should never be based on analyzer price alone though.
Understanding “What else is in the gas stream besides H₂S?”, can provide end users with the appropriate analyzer from AMETEK. This question often determines whether the 9900 is a smart investment or an expensive mistake.
Two Very Different Approaches to H₂S Measurement
Although both analyzers can measure H₂S, they do so using fundamentally different approaches.
9900 - Direct UV Measurement
The 9900 uses high-resolution UV photometric technology to measure gas components directly in the sample stream. For many process gas measurements, this makes the 9900 an excellent and economical solution. However, the 9900 analyzer does not separate individual gas components in the sample stream, prior to measurement. As such, components of no measurement interest that have overlapping absorption characteristics with the desired analyte, can absorb some targeted UV light. This will result in artificially high concentration readings for the component of interest. The net result would be measurement uncertainty for end users.
9933 - Separation Before Measurement
The 9933 was specifically designed for natural gas impurity analysis. It incorporates a column block, similar in concept to a gas chromatograph. This high-speed column separates the individual gas species before detection. As a result, the analyzer can selectively measure H₂S, COS and MeSH, significantly reducing cross-interference from other compounds in the stream. Like the 9900, the 9933 contains an analytical bench that utilizes UV measurement technology to provide the concentration of the analyte of interest.
A Simple Decision Framework
Choose the 9900 when:
- H₂S is the only sulfur compound of measurement interest
- The process gas is well-characterized
- No BTEX, mercaptans, sulfur species, or unsaturated hydrocarbons are present
- Appropriate sample drying and conditioning are provided
- Lowest capital cost is a primary driver
Choose the 9933 when:
- Measurement of extremely low levels of H2S (single digit ppm) is desired
- The stream may contain carbonyl sulfide, mercaptans, or other sulfur compounds
- Sulfur speciation is required
- Future changes in gas composition are possible
- Operators want interference-free H₂S measurement
- Natural gas quality measurement is critical
- Measurement confidence is more important than analyzer purchase price
- The sample gas pressure is at least 100 psig
Conclusion
The 9900 and the 9933 were designed for different measurement challenges. The 9900 delivers economical, continuous UV gas analysis and can provide reliable H₂S measurement when the stream is free of interfering compounds. The 9933 adds proprietary chromatographic separation technology that isolates H₂S, COS and mercaptans from other interfering species before measurement, providing a higher level of selectivity and confidence.
When evaluating analyzer cost, remember: The price of an analyzer is paid once. The cost of uncertain measurements can be an everyday expense.
Learn more about the 9900 gas analyzer.
Learn more about the 9933 gas analyzer.