Smart ABB Digital Valve Positioner Boosts Argon Production By 10%

Stabilizes flow in air separation plant

A modern digital electro-pneumatic positioner from ABB minimizes flowrate swings of rich-liquid vapor at an air separation plant in Louisiana. The new positioner replaces one installed on the actuator of a 20-inch butterfly valve. Tighter control of flowrate has helped to stabilize the sensitive cryogenic distillation process, increasing argon production by 10%. The plant employs cryogenic fractional distillation to separate air into its major components: nitrogen (78%), oxygen (21%), argon (0.96%).

The plant controls the amount of rich-liquid vapor coming off the argon column, which in turn controls the amount of crude argon flow coming into this column. A 20-inch Jamesbury butterfly valve regulates the flowrate of the rich-liquid vapor.

The left side of the graph shows the rich-liquid vapor flowrate swings caused by the original installed positioner. The right side shows the same flowrate following installation of the new ABB smart TZIDC positioner. The plant manager notes that flatter flowrates establish better system equilibrium, maximizing product purity. The plant can now run the air separation columns under tighter control, which results in production of more argon--estimated at about 10% more.

About ABB
ABB is a leader in power and automation technologies that enable utility and industry customers to improve performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries and employs about 124,000 people.

SOURCE: ABB