Brains not brawn

As in any sector of the petrochemical industry, ensuring the reliable operation of rotating machinery in the LNG industry is not a trivial task. Pumps, in particular, play an indispensable role in compressing gas to convert it into a liquid for efficient transportation and storage. In addition to pumps, air cooled heat exchangers play a very important role. An average LNG train has 150 - 200 air cooled heat exchangers typically ranging from 22 - 45 kW. They are often difficult to access so remote monitoring is ideal in this application.

Monitoring the condition and performance of pump applications in these extreme operating conditions, often in hazardous areas, is a costly and time-consuming activity. Generally based on a preventive maintenance philosophy, condition monitoring requires maintenance teams to manually gather data, analyse it, and generate status reports. This data is critical to preventing unplanned downtime and production losses, as it offers an insight into the health of equipment.

Thanks to recent developments, the safety risks associated with data gathering in hazardous areas have now been greatly reduced with a new generation of wireless smart sensors. These sensors enable operators to remotely monitor the health and performance of assets such as motors and pumps, to help predict incipient failure.

Where can smart sensors be used in the LNG environment?

Smart sensors can be applied to a wide range of motors used across an LNG plant, such as to pump process water and chemicals and to drive compressors. They can also be used on motors, mounted bearings, and gearing operating fans in air cooled heat exchangers and cooling towers.

The profitability of an LNG production plant is directly affected by the applied maintenance strategy and its impact on plant reliability. Redundancy, for instance, is a common approach to improving the reliability and availability of critical components, but it can sometimes have the opposite effect. When a plant follows a redundancy approach, the maintenance team can change a motor when it fails, but without knowing why it has failed. This means there is the possibility that the other redundant motors will fail for the same reason. Motor replacement can be a lengthy task that can take hours when working in a hazardous area. If a number of motors fail within a relatively short period, then even with redundancy there is a risk of an unplanned plant shutdown and loss of production.

While many LNG plants manually monitor motors once a month or once every quarter, the benefit of using smart sensor technology is that it collects and transmits a high volume of data wirelessly on a frequent and regular basis. This delivers real-time, actionable data that provides the foundation for adopting a condition-based maintenance philosophy, rather than replacing equipment according to its calendar life.

This is an abridged version of an article that was originally published in the September 2020 issue of LNG Industry. The full version can be read here.

Read the article online at: https://www.lngindustry.com/special-reports/16092020/brains-not-brawn/