Fouling Diagnosis of Pennsylvania Grade Crude Blended with Opportunity Crude Oils in a Refinery Crude Unit's Hot Heat Exchanger Train

The continual decline in the quantity of legacy Pennsylvania grade crude oil coupled with recent volatile crude oil prices has prompted American Refining Group to start processing a wide variety of opportunity crudes to expand its crude oil feedstock slate to maintain profit margins. As opportunity crude usage increases, crude oil fouling and unexpected corrosion have become major issues in the refinery crude unit's hot heat exchanger train (HHET) and other process units. Crude oil fouling in the refinery has resulted in increased energy consumption, reduced throughput, and more frequent shutdowns. In this work, fouling at the refinery crude unit HHET resulting from the impact of Pennsylvania grade crude blended with opportunity crude oils was investigated. Thermal and hydraulic fouling models were studied to detect changes in the fouling behavior of the crude unit's hot heat exchanger train. Phase separation of crude oil to coke fouling mechanism was described in detail. Several crude oil fouling diagnostic tools were used to determine the root causes of fouling including foulant chemical characterization, crude oil compatibility, caustic injection evaluation, crude furnace operation, crude corrosion, and in-house developed fouling indices.