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How can fractionation upgrades be achieved without expensive metallurgical upgrades?

Oct-2024

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Andrew Layton, KBC (A Yokogawa Company), Andrew.layton@kbc.global

Improved fractionation profitability can be achieved in several ways: corrosion control, tray technology, KPI/monitoring developments, energy pinch studies, and live computer models.

Corrosion control involves managing corrosion from sources such as acids, mercaptans, and salts. Solving these issues allows for processing cheaper crudes and delaying turnarounds. The alternative to using metallurgy is often different chemical packages added to the feed or overheads of fractionation systems and other equipment like desalters.

Unfortunately, this approach may not always solve the problems. For example, crude overhead corrosion control creates almost as many problems now as it did 50 years ago. Other techniques are required, some of which are difficult to implement in an already-designed unit. Mitigation for existing units can be achieved through improved modelling, monitoring, and process and reliability KPI development, as well as some simple design changes in areas that are often overlooked or discounted as critical.

Tower internals designs are continually being upgraded by vendors to improve efficiency and capacity. However, the benefits of these improvements are often lost by poor operation due to fouling corrosion or poor control. These problems can be mitigated by improved KPIs and modelling to identify when efficacy is being lost or when process changes can improve operation. Thus, live modelling for rapid identification of both process and reliability deterioration enhances the value of improved control systems. Monitoring may include flow regime modelling, mixing effectiveness, pressure drop, and velocities/partial pressures as a few examples.

Energy minimisation is another key factor in improving product value, as well as helping to meet any carbon footprint targets and removing bottlenecks such as furnaces and rundown cooling limits. Rundown cooling is often one of the first constraints encountered with higher ambient temperatures. Energy pinch studies will help debottleneck fractionation heat sources, and the potential use of various heat pumps will further reduce the carbon footprint when using low-temperature heat sources below 120°C.

Oct-2024