Last week, Emerson Consultant James Beall was working with a major U.S. plastics facility on the Texas Gulf Coast, helping the firm figure out how it might save some of the money it spends on distillation energy by using Emerson’s Smart Process Distillation Column Optimizer (brochure pdf, product data sheet pdf), a specialty application package for the DeltaV digital automation system. Instead, James found those savings in better product recovery.
With multiple interacting variables, distillation columns are famously finicky, even when there’s no interference from changes in the feed flow rate, feedstock composition, or even ambient temperature.
Of course, James first looked at reducing the energy use, since it’s generally the most expensive part of distillation. In fact, depending on the individual plant, distillation can consume up to 40 percent (pdf) of the energy used by production processes.
Reducing variability and improving control responses with Emerson’s Smart Process Distillation Optimizer
But all told, this particular distillation train didn’t use that much energy — only about $200,000 worth per year. And when James did the analysis, he found that Smart Process Distillation Optimizer wouldn’t be able to save enough energy to make a big difference.
Fortunately, saving energy isn’t the Smart Process Distillation Optimizer’s only capability — it’s also often able to improve product recovery. Using model predictive control to describe and predict how the process behaves, the Optimizer can make control responses that reduce variability, adjust throughput to compensate for disturbances, and run closer to process limits.
And James found using the Optimizer would allow this plastics facility to recover 20 percent of one of its valuable products — previously, the facility had left that 20 percent in the stream, which is ultimately flared.
The savings amount to about $300,000 per year — high enough to pay for the upgrade to Smart Process Distillation Column Optimizer in only nine months.
If you’re going to this year’s Emerson Exchange in Grapevine, Texas — near Dallas — you’ll be able to catch James live as he presents any of four sessions:
- DeltaV SmartProcess Application Strategy Achieves Faster and More Efficient Control of Revamped Ethylene Furnaces
- Unique Uses of Embedded DeltaV MPC
- Control System Migrations Gone Wild! – Best Practices and Lessons Learned
- Improving Regulatory Control Performance
Update: I just spoke to James today, and he reports that after visiting the plant again, he discovered that using the Optimizer could improve the facility’s recovery of yet another plastics product from its stream — and with even better financial benefits.
