Client Midwestern refinery

Location USA

Sectors Petrochemical and refining

The challenge

Huge damage bill from heavy hydrocarbons 

It’s amazing how much damage a few heavy hydrocarbons can cause. With $50 million already down the drain, a Midwestern refinery was desperate to fix a stubborn problem within its recycle gas circuit. 

The issue was a tricky one – the temperature in the low pressure separator wasn’t quite right, and it wasn’t doing its job of separating hydrocarbons and hydrogen gas from upgraded naphtha hydrogen gas. The warmer temperature stopped heavier hydrocarbons from condensing, which in turn caused downstream headaches. The refinery had suffered significant downtime; the loss of revenue was huge.

Project fact file

$50 million

Losses already clocked up

90% %

Reduction in inlet temperature

13% %

Above target design duty

The solution

Glycol cools down hydrocarbons at the right time and place

The refinery needed to condense the heavier hydrocarbons in the separator instead of in downstream piping.

We got to work designing a system to get the refinery up and running again. We used the existing exchanger, but instead of using plant cooling water we used our own recirculating glycol solution from an air-cooled chiller. It would easily cope with the seasonal changes in ambient temperature, which had wreaked havoc with condensation in the past.

the aggreko difference

We rise to the challenge of solving complex cooling problems in unique spaces.

The impact

Great cooling gains, no more money lost 

The gas going into the separator was cooled from about 250°F (121°C) to a chilly 40°F (4.4°C) at a design duty of 4.3 million British Thermal Units per hour. Our maximum duty of 4.87 million British Thermal Units per hour was 13 per cent above the project design duty. The hydrocarbons could condense and be captured before travelling downstream and messing up other systems. 

Overall, it meant that the refinery avoided further damage to its recycle gas circuit –no more hefty maintenance bills. Our cooling also helped improve the performance of the low pressure separator, so it could do a better job of purifying the upgraded naphtha hydrogen gas.

“There’s a lot of knowledge that goes into designing optimum systems for the different gases that are moving through a refinery. At Aggreko, we’ve got this knowledge in spades.”