Client Midwestern refinery
Sectors Petrochemical and refining
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
Losses already clocked up
Reduction in inlet temperature
Above target design duty
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.
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.”