MFAME – published an exclusive news on ABB’s new MXP turbochargers where ABB, at the 28th CIMAC Congress, Helsinki, Finland, unveiled a new turbocharger which is exclusively made for ship’s auxiliary engines.
In line with that – here are more insights on these turbochargers.
ABB said that the turbocharger’s robust construction is intended to ensure trouble-free operations using HFO, while specific attention has been paid to making service and maintenance work by ship’s crew straightforward.
In developing this new product, ABB said that the company wanted to achieve
- a service-orientated design
- competitive overall cost
- strong performance in terms of fuel efficiency and load response
“The approach we have taken all along has been to design the turbocharger to fully enable the end user to carry out service work themselves, using the specific service instructions we provide,” said Roland Schwarz, head of ABB Turbocharging Marine Auxiliary Product Group.
Most marine auxiliary engines run on HFO, which can produce heavy contamination of the turbocharger turbine if the fuel quality is poor and the exhaust gas temperatures are high. Very hard deposits can form on the nozzle ring, which can have an adverse effect on turbine efficiency, increase exhaust gas temperatures and lower engine performance. In some cases the rotor can get stuck once the engine is stopped.
According to ABB, the MXP turbocharger has specific attributes that will allow it to operate much more efficiently in such conditions. The turbine nozzle ring is made of high temperature resistant steel and treated with a wear resistant material to cope with the highly erosive particles within the HFO. The design of the nozzle ring also features fewer but larger vanes compared to existing products, to better cope with fouling and wear effects when running on HFO fuel.
The MXP’s radial bearing and adjacent damping elements have similarly been designed to cope with high levels of HFO-related fouling on the turbine rotor and any consequent unbalancing. Its bearing casing is protected from hot exhaust gases by using a cast head shield, while the impellers have been designed to resist wear by minimizing the penetration of HFO residues and abrasive dirt particles into the turbine. The air filter silencer has also been made of anticorrosive sheet metal.
The MXP turbocharger has also been designed with on-the-spot service requirements in mind, ABB said. Particular attention has been put to the need for rotor balancing during service, which has been minimized and can be avoided altogether once the rotor has been mechanically cleaned; a cleaned and brushed rotor will not require any balancing during an overhaul. Eliminating rotor balancing is a key factor in simplifying maintenance by the ship’s crew, ABB said.
Fewer parts also mean fewer steps to complete assembly, making turbocharger demounting and reassembly by service technicians at sea far simpler. The complete bearing unit incorporates the radial and axial bearing parts, the thruster ring and the compressor side shaft sealing arrangement. The unit can be pre-assembled and stored onboard as a spare part, in case servicing is required.
Again, ABB said the casing design and the screws used to assemble the turbocharger have been selected to facilitate access, while all of the screws within a particular frame size have the same thread dimension, strength class and tightening torque. Any maintenance work can therefore be carried out using simple, standard tools, the company said. The shortened bearing casing also helps make service access easier for the crew.
“Only commercially available tools are required and it is relatively simple to demount both the bearing case and compressor wheel,” Schwarz said. “As a result, the turbocharger can be serviced next to the auxiliary engine, without any need to remove it from the engine room.”
Taking a service-led design approach resulted in MXP’s condition-based maintenance concept which is supported by an interactive and intuitive digital self-service maintenance application for use on hand held devices, so that the crew are able to carry out service.
ABB pointed out that turbocharger conditions, including wear and fouling rates, can depend on various factors, including HFO fuel quality, the type of marine auxiliary engine and the type of vessel. A single turbocharger design will never experience equivalent level of wear in what can be widely varying conditions, or the same replacement interval for spare parts. The condition-based maintenance concept can adapt to the day-to-day conditions faced by individual units, the company said, avoiding the premature exchange of parts and helping to reduce maintenance costs.
ABB said the MXP’s configuration is also distinguished by optimum performance it achieves in part load conditions. Turbine and compressor matching can be adjusted, without compromising performance at full loads, to accommodate the moderate load cycles marine auxiliary turbochargers routinely experience. By increasing the diameter ratio between the turbine wheel and the compressor wheel part load efficiency within a loading range of 40 to 80% is significantly improved.
Schwarz said the MXP should be considered as a direct response from ABB Turbocharging to market needs. “We look forward to discussing the value this turbocharger can bring to the market with engine builders and vessel operators, thanks to its optimized performance which matches the actual operating profiles of most marine auxiliary engines.”
Available for delivery in early 2017, MXP units will come in three different frame sizes, covering a flow range of 0.6 to 3.5 m3/s.
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Source: ABB & Diesel Gas Turbine