Overhauling steam turbines
Around an ethylene plant in 30 days
The city of Barrancabermeja is known as the “oil capital” of Colombia — a good place for an ethylene plant. Our customer’s mill can produce 44 000 tons of ethylene and 8 800 tons of propylene per year — 144 tons per day. Such mills run continuously.
Sulzer’s service centers in Texas and Bogotá worked together to inspect and repair the three turbines. Preventive maintenance keeps installations running reliably and at maximum efficiency. To minimize production losses, maintenance must be done quickly. For its steam cracking process, the Barrancabermeja plant employs steam-powered turbine compressor trains before the distillation phase of processing the gases.
Ethylene gets turned into the world’s most-used plastic
Ethylene is a colorless, flammable gas. It is widely used in the chemical industry. More than half of the ethylene supply goes toward making polyethylene: plastic used for packaging and carrier bags. Ethylene is often produced in the petrochemical industry by steam cracking.
Planning started one year ahead
Doing maintenance during a planned outage requires careful management. Since 1999, the Colombian mill relied on Sulzer to repair its turbomachinery. The customer initially contracted Sulzer to perform all the planning activities for the compressor deck during the outage and to inspect and repair the spare set of rotors. Sulzer exchanged the running compressor rotors with the shop repaired spare units which were repaired in Houston before, to allow fast turnaround. Subsequently, the customer asked Sulzer to carry out all compressor deck activities during the outage. All of this work had to be completed within 30 days.
Those who have ever organized a wedding know what it’s like to plan a one-day event. Imagine how long it takes to plan a 30-day overhaul with 12 service technicians. That’s what we did.
Excellent project management
Sulzer deployed two project managers to oversee the schedule. One was José Saldana, a talented young engineer. “The project manager is responsible for the smooth workflow of the whole project. One important planning step is to break down the overhaul maintenance work into sequences of work. Then we list all requirements for this sequence, timeframe, and how many people are needed to manage the project on time.”
Overhaul and testing in Houston
The spare rotors that were installed by our Field Service team had been previously remanufactured at the Houston facility; each component had been brought back to engineering specification. “Houston is our flagship repair center. We have a systematic approach with checklists for each remanufacturing order. Starting with an initial inspection, and comprehensive measurements followed by grit cleaning and disassembly with further non-destructive testing (NDT). This allows us to determine exactly the repairs we will recommend to the client,” says José Saldana.
In cases where the rotor has suffered a shaft failure at one end, it may be necessary to replace the end with a shaft stub. Where original components, such as impellers, are damaged, we must create new parts.
Once the engineers have refurbished or remanufactured the components, they then restack and balance the rotor. Large components, such as the Colombian plant’s steam turbines, require a large balancing bunker like ours that provides state-of-the-art analysis (Fig. 2).
Back in full working order
Sulzer handed the complete compressor deck back to our satisfied customer on time. After that, our field service team helped startup the compressor deck and enable the plant to commence normal production.