Last month, MTU Aero Engines rebranded its gas turbine competencies under the name MTU Power.

The new brand consolidates the existing engineering, manufacturing and aftermarket expertise across all MTU’s business units: Aero Solutions, Brush Seals and MTU Maintenance.

Gregor Stöcker, of Industrial Gas Turbines at MTU Power, says the overall aim is to “harmonize the extensive experience, in-depth knowledge and creative, never-give-up mentality within the company and bring its services even closer to the customer.

“We want customers to be able to find what they are looking for, fast. And we want to be more visible in the market.”

‘Closer to the customer’, he explains, means: “We want our customers to be able to find us and the information they need quickly – as a company with significant roots in the aerospace industry, this was at times confusing.

“But we also mean being physically close to the customer and we have been working really hard on this. We moved our US-based level II shop to Dallas, Texas in 2016, so the focus last year was on maturing the services we offer there.

“We also increased capabilities overall, for instance by adding a DLE mapper to our team as well as introducing local heat treatment for lever arms and improving the cooling fluid systems of our grinding machines. And we expanded our lease and rotables pool, too.”

He explains the need to expand the lease and rotables pool. “One of the things we say is ‘efficiency is power’. Lease engines and rotables are used to avoid downtimes when a customer’s turbine is with us for maintenance, repair and overhaul.

“Take the US market, where a lot of LMs are used as peakers to help cope with spikes in power demand. The machines see multiple starts and shutdowns, leading to more material fatigue. If I’m a peaker operator and my hot section fails, I need a replacement fast so I can be back up and running when the grid needs me. Electricity demand isn’t going to wait for anyone.”

Looking outside the US, Stöcker believes “we are seeing some recovery in the gas market in Europe”.

The new brand consolidates engineering, manufacturing
and aftermarket expertise
Credit: MTU Power

“For instance, the UK government announced recently that the country would be shutting down all coal-fired plants by 2025 and introducing more gas and nuclear energy to compensate for this. Of course, Asia-Pacific is a growing market with demand for power trains for LNG plants. And in Africa, the oil and gas segment is on the up. We’re getting a lot of interest in and from that region.”

He says that overall, MTU has “certainly seen the effects of a low oil price in recent years, with customers from the oil and gas industry, in particular, looking to save as much as they can on maintenance without compromising on reliability. Though cost-saving has always been a priority, of course.”

Stöcker highlights how MTU Power helps customers reduce and optimize costs. “On a general level, we perform customized workscoping, which means that the workscope is defined entirely according to customers’ needs – from ‘light’ performance restoration to complete overhaul.

“We won’t exchange in new material if there is a repair available, as repairing is always more cost effective than replacing. Repairs generally cost up to 20 per cent of a new part and we perform the large majority of repairs in-house. We can also build in overhauled material as a cost-reduction method.”

‘Repairing is always more cost-effective than replacing’
Credit: MTU Power

Asked to highlight any particular issues he is seeing at the moment, he highlights water washes. “We had an interesting LM6000 case last year. The turbine showed strong oxidation/corrosion on the stage 1–3 low pressure turbine nozzles, although the turbine only had
25,000 hours of service time, which is about half what we would expect before seeing it for performance restoration.

“The resulting oxide layers caused numerous cracks and the parts’ wall thickness was significantly lower than originally. During investigation, we discovered that the aluminide-coated surfaces had been exposed to unusually aggressive contaminants, as found in engine cleaners.

“When too little water is used during a compressor wash, the washing agent and dirt can be re-deposited on the turbine components. So our tip to operators would be to really pay attention to the water during washes, making sure there is enough for dilution and rinsing. Ideally, surfactants would also only be used for compressor washes.

“We also saw a fuel system contamination through dirty water that caused a number of issues with the respective LM6000 and LM2500 turbines recently. Fuel systems aren’t pressurized during the water wash procedure and we believe the contaminated water wash fluid was able to enter the fuel system via the gas injection swirlers. Our recommendation here would be to use instrumentation air during the wash, or reduce the need for water washes in general through the installation of a three-stage high-efficiency particle air (HEPA) filter system into the air take.”

But Stöcker is keen to highlight services that can be done in the field to avoid a shop visit altogether.

“We would always recommend regular inspection, for instance. But field service experts can also be a good option for troubleshooting or organizing module exchanges.

“Take for instance a hot section exchange, as mentioned above. It is possible to make the swap without removing the power turbine and turbine mid-frame from the package or opening the flange that connects the two.

“Of course, this takes care. Sometimes the power turbine seal will clamp to the stage 1 disk, and you want to avoid any seal ring damage. But, with support, the intrusion can be minimal, just like the downtime.”