Ethylene facility extends furnace operational runs

Challenge

Multi-Chem, a Halliburton Service, was approached by a large ethylene facility on the U.S. Gulf Coast to supply a furnace antifoulant. This facility, which operates several gas crackers with a 100% ethane feed, needed to extend the operational runs of its furnaces, which typically lasted 15 to 20 days without treatment. After consulting with the customer, Multi-Chem customized an alternative product that, after several lab tests, was approved for trial.

Solution

Multi-Chem recommended PPA-321 antifoulant which creates a film over the tube walls, providing a surface bond of P-S moiety that limits coke formation on tubes.

• Dosage/treatment: The initial treatment involved a high-dosage feed rate of 100 ppm during the first 24-48 hours to create a protective film on the furnace tubes. For maintenance, the dosage was reduced to 5 ppm.
• Monitoring: During the trials, Multi-Chem closely tracked tube metal temperatures, pressure drops, and other key operating variables.
• Showing value: Multiple Regression Analysis (MRA) has proven to be the optimal tool for demonstrating the value PPA-321 delivers to customers.

Result

The application of PPA-321 was able to extend the furnace runs to more than 50 days from an average, baseline performance (without treatment) of 15 to 20 days, an extension in the decoking cycle of at least three times.

PPA-321 works particularly well in furnaces that have short decoking cycles determined by pressure drops. The furnaces where the greatest performance was achieved, are ones characterized by fouling in the front-end.

In this situation, furnaces quickly build up considerable pressure drop, resulting in limited flow to the remaining tubes, a decrease in cooling, and making the furnace tubes work hotter and coke faster.

The PPA-321 product prevents quick, front-end fouling and results in easier and cost-efficient management of coking build-up.