The Monitor

Production Process Insights

How to best obtain representative samples from your process stream

Posted by Jeff McKinney on 12/3/15 2:13 PM
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MIL_transp.jpgRunning an efficient operation requires analysis of controlled, real-time data obtained through representative sampling within a production environment. This data is needed to provide the critical insights needed to control and optimize processes. Representative sampling is the act of capturing fresh product from the process stream for analysis.

Why should you sample?

For several reasons, it is essential that chemical and petrochemical application samples are repeatable and reliable, every time. Samples from oil and gas refineries and chemical or petrochemical plants generally are needed to:

  • Validate hydrocarbon constituents or quality
  • Determine process plant efficiency
  • Ensure that products are being made according to specifications
  • Troubleshoot and determine any source of product contamination
  • Meet regulations

It is essential that during sampling the products are not contaminated by handling and are a current, real-time representation of the stream from which they are captured.  To obtain an accurate sample, samplers must be specifically designed for the industry’s unique application needs. However, many plants use samplers cobbled together from older pieces and parts that may not be suitable, rather than using samplers or sampling panels proven in the refinery, chemical and petrochemical environments. This can mean a sampling operation that is ineffective, or worse, unsafe.

Over the course of a year, an operator may collect hundreds of samples – which can add up to tens of thousands of samples collected over a career. Each sample collected may pose a physical or health hazard, so samples must be taken safely and correctly using the appropriate equipment and containers.


Low-emission samplers are designed to provide the greatest amount of protection for both operators and the environment, with no spillage and minimal volatile organic compounds (VOCs) – organic chemicals that have a high vapor pressure at ordinary room temperature. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate from the compound and enter the surrounding air. A key design feature of low-emission samplers is closed-loop, zero-leak solutions to prevent VOCs and other chemicals from entering the atmosphere, as well as a purge port, which ensures that the sampler is adequately cleaned before a new sample is taken.

The best low-emission samplers are proven closed-loop, zero-leak solutions designed to capture a true representative sample in high pressure, high temperature conditions, and meet NACE standards and are NACE MR0103-2012 compliant.

For true representative sampling and safety, oil and gas refineries and chemical or petrochemical plants must employ safe and accurate sampling solutions. Some of the best solutions used by refineries and plants worldwide are Sentry® low-emission manual samplers and Sentry ISOLOK® automatic fixed volume samplers.

Learn more about our industry solutions here.

This article was originally published on our website.

Sentry's Industrial Representative Sampling eBook

Topics: Downstream

Written by Jeff McKinney

As an industry manager for chemical and petrochemical refining, Jeff is an expert in those markets and is experienced in power generation as well. Jeff is focused on serving these key markets and sharing information on how Sentry sampling and monitoring products and systems can meet any petrochemical or chemical application, anywhere. He is responsible for our market strategy and product offerings, and is always interested in exchanging information on specific industry applications and solutions that meet customer needs.

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