Designing a Crude Unit Heat Exchanger Network
SUMMARY
Preheat train design for heavy Canadian crudes can be very challenging, requiring an approach not normally required with other crudes.
TEXT
A well-designed crude and vacuum unit (CDU/VDU) heat exchanger network is essential to meet product yield, product quality, unit reliability and crude processing flexibility objectives when processing heavy crudes. Preheat trains conceived with the wrong flow scheme or those with multiple parallel paths that are complex to operate rarely have the flexibility needed to handle a range of crude blends or even the variability of many heavy Canadian crudes. Standard shell and tube exchangers designed with low velocity are prone to rapid and heavy fouling.
It is becoming ever more important to temper crude train design that has been developed from composite curves, optimal energy targets and pinch points with crude unit experience and know-how. Practical concerns include operability, reliability, exchanger type and minimal fouling design. Real-world experience using flexible preheat networks, good exchanger design practices and proven exchanger technology is proving to be more important than theory. This article covers practical considerations when designing CDU/VDU preheat networks for heavy crude processing...