Smart cooling makes savings for refinery

Vacuum distillation is a critical part of the refining process. To produce gas oils of acceptable quality, a delicate balance between the vacuum pressure and the heat of the system needs to be maintained.

A southeast refinery was struggling to get it right. The pressure wasn’t low enough and the chiller wasn’t cool enough. The resulting gas oil was off-spec. To fix the problem, the refinery had resorted to blending fire water with the discharge water from the chiller. As a result, operating costs were mounting.

Our APS team set to work diagnosing the problem and quickly discovered the cause of the imbalance – the existing cooling unit was undersized by 50%. Armed with this knowledge, we engineered an energy-efficient cooling system that would stabilize vacuum tower pressure at the desired lower level. The whole thing was fully operational within four days.

With our cooling system up and running within days, cost savings quickly added up: US$20,000 a month from reduced power costs, and a further US$12,000 a month by eliminating the fire water blending process.

More importantly, our cooling stabilized the system at an ideal low pressure, helping the vacuum distillation tower do a much better job. With the gas oil meeting specifications at the desired feed rates, our customer could now consistently meet production quotas.