Choosing the appropriate portable analyzer requires an understanding of the use case. We use an application data sheet to collect the information needed to recommend a dedicated analyzer for a given application. The same rigor is appropriate when choosing the portable. Unfortunately, many plants choose to carry one portable (or one type of portable) for a measurement type. In this case, it is important to seek out an analyzer that best matches the attributes required for the majority of the use cases. For simplicity, I will focus on moisture measurement, but this thought process can be applied to any measurement type.
Pipeline natural gas operators may have only one application: pipeline natural gas. In this use case, the operator may prefer to use an aluminum oxide-based analyzer, as it can be used at pipeline pressures, or, since each of these points of measurement vent to low pressure, they may choose a laser-based portable to avoid the need for regular calibrations, to mitigate the impact of fouling due to triethylene glycol carry-over, and to maximize speed of response.
In a refinery or a chemical plant, there may be a dozen different applications in which moisture measurement is needed. These may include liquid feed streams, liquid product streams, hydrogen recycle and hydrogen make-up gas streams, inlet and outlets of molecular sieve dryers, industrial gas streams, and instrument air streams throughout the plant. Notice we have both liquid and gas streams. Some are at high pressure and others at relatively low pressure. The moisture measurement range for each of these applications is quite different. Here, the attributes that may drive the decision are background gas/liquid independence and wide measurement range.
In your use cases, technology attributes may include:
- effective measurement range of the technology,
- process pressure at which measurement is made,
- background gas considerations,
- making the measurement in the phase of the fluid (liquid or gas),
- speed of response required,
- immunity to contaminants inherent to technology or by design,
- calibration frequency, and
- required accuracy.
For moisture measurement, an aluminum oxide portable analyzer will check most of these boxes, especially with a properly designed sample system with a proven track record. When a portable analyzer is required for a relatively well-defined set of applications, a laser-based portable analyzer will provide the benefits of increased immunity to contaminants, maximum speed of response and accuracy, and minimal maintenance requirements.
Choosing the technology is only one step in the process. Choosing a partner with whom to make this measurement may be more important. Does this partner have decades of experience making these measurements and making them with a portable? Local/in-region calibration capabilities and service centers may be critical. Local experts that can visit the plant, train the operators, or even make the measurements may tip the scales for you. The ability to offer multiple portable technologies and solutions mitigates the possibility of force-fitting a technology to the application.
The winning attributes of a portable analyzer include technology considerations and vendor capabilities and experience. Without making this a commercial for Panametrics products, services, and capabilities, it is easy to write an article on this topic, given that the PM880 and Aurora TransPort are backed by legacy of superior technology, calibration, sample system design and implementation, application successes, and highly-localized and expert support. All these winning attributes in combination make for the most successful portable moisture analysis.
Author – N.J. Sparages – Panametrics
