Process cooling solution extends compressors' lube oil lifespan

A major petrochemical plant in South Korea was experiencing high compressor lube oil temperatures due to the rising summer heat. Without intervention, production at the site could be compromised, with the worst case causing a shutdown.

It was anticipated that the situation would further deteriorate in the summer due to insufficient cooling capacity of the lube oil with the current cooling set-up. When higher than desired, the temperature shortens the life expectancy of the lube oil.

Consequently, this can potentially decrease the efficiency of the compressor or worse, result in the equipment breaking down. The repercussions would impact production continuity and cause huge financial implications for the plant.

Setting the foundations in 2020
Aggreko’s process design and engineering division - Aggreko Process Services (APS), taps on a global team of process engineering experts to advise and design high value process solutions for the most demanding and specialised refinery petrochemical processes.

The customer in this case was drawn to this exact expertise of Aggreko to help them develop a bespoke solution to expand their cooling capacity, resolving the high lube oil temperature issue.

Aggreko conducted a site visit which put together a process design package with cooling capacity expansion for the lube oil cooling process. The visit was essential in deciding the location to position Aggreko’s equipment, which would in turn determine the hose run length and pressure drop in order to correctly size the booster pump. To cater to the customer’s added requirement of varying cooling capacity, a bypass line was added around the air-cooled chiller to throttle the flow.

As the plot space allocated for Aggreko’s equipment was quite a distance away from the nearest substation, we also engineered a power supply to power the air-cooled chiller and booster pump for an integrative turnkey solution.

Delivering with flexibility in 2021
For 2021’s deployment, the customer required a tweak in the chillers’ set-up due to a local technical and environmental regulation. We responded by adapting the setup with 4 smaller-sized module chillers which are 150kW in individual capacity to deliver the same total cooling impact for the process unit. The approach helped with the financial impact for the customer, with zero capex, where Aggreko sourced and invested in this new set of chillers to deliver this solution.

The customer was able to maintain their lube oil temperature according to their stipulated requirement of below 28 °C, consistently throughout the summer months, thereby averting any potential breakdown of compressor and ensured production continuity.

Typical annual maintenance costs of a compressor are circa 10-15% of operating expenses and any damage to the compressor due to lube oil issues could easily double or triple the maintenance costs. Also, the potential losses incurred from lost production days due to the compressor breaking down were avoided due to the temporary cooling system deployment.

The customer was thoroughly impressed with Aggreko’s solution, so much so that they have decided to repeat this job with an increased scope in 2021. At the time of writing, the temporary cooling solution had just been commissioned and will deliver consistent cooling from July to September for the second consecutive year.