Audit proposals therefore need to be exceptionally detailed, including vendor information. It is advisable to choose an equipment vendor that offers service as well; for example, Sentry Equipment offers all service in-house, without outsourcing to another company that could stymie efforts to implement an audit. Choosing a full-service partner allows a plant to seamlessly request and implement an audit with the original equipment vendor.
A valuable SWOT analysis A sampling audit is a technical review of a sampling system’s strengths, weaknesses, opportunities and threats (SWOT). Audits are conducted by certified sampling experts to identify SWOTs in business areas, sampling units/types and within specific samplers. The analysis reviews the following: If any updates, modifications or new systems need to be added. Modifications can include: retrofits of current equipment, replacement of worn lines, installation of new sample coolers, analysers, etc., or adding a secondary cooling system or a magnetite trap. Priority of divisions based on the refinery’s needs. Estimated costs of potential repairs, edits, etc. Risks associated with not taking recommended action(s). For example, the audit might note that close attention should be paid to the needle assembly on a bottle system,
as various samples tend to leave crystal-like deposits that can lead to plugging. Audits also take into account pressure (PSI), temperature, and processes being audited to make a series of recommendations for the refinery.
Tailored recommendations Each audit should be customised to the plant and domains or locations within the plant. No two samplers or processes work the same way, and many sampling areas are often under different types of management, depending on the location within the plant. These elements need to be considered when evaluating the system as a whole.
Prioritised actions The result of an audit is a comprehensive list of recommended actions that plant operators can take to optimise their sampling systems, from repairing equipment to replacing an entire system. When identifying needs, the sampling expert conducting the audit should use a system for identifying priorities. For example, Sentry provides comprehensive insight into all samplers within a plant, regardless of manufacturer or brand, providing a maintenance schedule or best practices to ensure the longevity of repairs, modifications and replacements.
Table 1. Example of Sentry Equipment’s audit report for a refinery customer Sampler type
Key components
Routine maintenance guidelines
Notes
TSI-3 bottle system
TSI-31-T-SS sample valve
Inspect sample valve for proper function. Replace if cycle positions are not producing desired results
This system is not currently functioning. Main line feeding the panel is plugged. Additionally, the N2 system has at minimum a faulty flow meter. If plug is cleared, entire N2 system should be serviced before returning to service
Table 2. Example of a sample station priority matrix Highest priority
Medium priority
Lower priority
Little to no existing sample station infrastructure and regularly caught, higher risk samples
Some existing sample station infrastructure but in very poor condition and largely not compliant with O-029
Existing infrastructure is mostly working and largely compliant with O-029 but needs some minor improvements to be fully compliant
Samples from bleeders Samples from behind single isolation Sour samples in fresh air High pressure samples Certain bag samples which could be caught through sample stations Samples without essential safety features (boxes, cooling systems, etc.)
Stations with broken valves/vents Stations which are totally plugged or inappropriately designed for sample being caught Stations without double isolation or safety purges like purges/vents Stations still mostly usable but with serious flaws
Stations which need spring loaded valves Stations with vents not routed far enough away from the collection point Stations with inappropriate thickness of needles Stations missing gauges and flowmetres Stations which do not have constant circulation (if required)
May 2021 24 HYDROCARBON ENGINEERING
An audit helps optimise plant systems Running an efficient refinery requires real-time data analysis. Gleaning critical insights from sampling equipment is essential to product quality, safety and operational processes. A properly designed representative sampling system with the right sampling equipment ensures process samples are repeatable and reliable to help refineries maximise return on investment, better manage loss control, and reduce operating costs.
Matching the equipment to the application Capturing representative samples and protecting the operator is critical in high-temperature and high-pressure applications commonly found in refineries. It is therefore essential to match an application to the sampling equipment. A sampling audit can also ensure that the right equipment is matched to the application(s) within a refinery. Automatic samplers help to optimise sampling accuracy and repeatability for hydrocarbon liquids such as crude oil, condensates and oil and water mixtures. They isolate the process without interrupting the process line, and offer a variety of different types depending on the application.
