Brad Parsons

Fin Fans, How Many Can You Afford to Lose?

The Australian gas industry has never been in a better place, with the nation now occupying the top of the podium of gas exporters, followed by Qatar and US (1). This is an amazing achievement we can and should be proud of, but obviously resting on our laurels won’t keep us in the leadership seat.

Significant investments in new assets were made and several are now operating, so what else can we do to make sure these investments were worthy and that we can make the most out of them?

According to NERA, “The [oil and gas] industry should focus on improving its data analytics capability so it can recover the full value of its investments. The technology has the ability to predict process and equipment failures, leading to increased asset utilisation and overall operating cost reductions, significantly boosting competitiveness.” (2)

Among the hundreds of thousands of pieces of equipment utilised in this industry, the unsung workhorse has to be the humble ‘fin fan’ (or air cooled heat exchanger). There are hundreds of them in every single plant and, if a small percentage fail, the whole plant might have to be shut down. Typically fin fans are configured in banks of several hundred units, so the loss of only a couple of units is acceptable. However recently we are seeing an increase in failures which is putting pressure on the industry to look at new technologies that can help mitigate this significant risk to production outages.

The big question is why are these happening? Multiple challenges seem to be driving this industry wide issue. Firstly, the inherent design, which seems to be typically used in the Australian Oil and Gas industry, results in difficult to access, maintain and monitor fans.

Fin fans
http://www.whatispiping.com/air-cooled-heat-exchangers (figure 1)

What’s more, monitoring is typically done through wired sensors connected to the electric motor (figure 2). However from our analysis, failures are occuring on the top bearing of the fan itself, which is a difficult to [safely] access location. Top bearing failures have to be very significant to be detected on the drive motor (or bottom bearing). So monitoring the top bearing is the key to solve this. We’ve seen some instances where fans have cut through the fan ring (cowling surrounding the fan); metal on metal is obviously a significant safety concern.

Fin fans
http://www.korenergy.co.kr/En_template2/heat_fin.html (figure 2)

Secondly the drive for more energy efficient motors is driving the need to replace existing motors (as they fall due) with heavier configurations that weren’t necessarily considered in the engineering design specifications. This places additional pressure on the whole configuration.

Finally, in Australia much of our Oil and Gas processing is done in the ‘top end’ or northern Australia where temperatures can reach 40+ degrees C or 100 + F. So continuously running cooling is essential for processing plants. This week the Bureau of Meteorology (BOM) declared that 2018 was the third hottest year on record (3). This trend doesn’t look to slow down with another heat wave moving across Australia this week.

Monitoring the health of fin fans can be challenging and costly. The safety implications are also a significant consideration as it requires placing workers in high risk and hazardous areas. Talking across the industry we are seeing workers doing daily inspections of fin fans in the hope of getting ahead of failures.

The industry shouldn’t have to accept this level of risk anymore. Technology is now available that can help mitigate this risk in a safe and effective manner. MOVUS has been working closely with customers in the Oil and Gas industry and developed FitMachine EX to address these challenges. How many fin fans can you afford to lose before a plant shuts down?

References:

(1) Manufacturer’s Monthly

(2) Oil & Gas Industry Competitiveness Assessment by NERA

(3) BOM declares 2018 Australia’s Third-Hottest Year on Record