In 1852 James Prescott Joule described the physical principle of the gas turbine – the thermodynamic cycle, also known as the Joule-Process for the first time. The initial ideas and concepts behind this invention date back as early as 1791.
Siemens Industrial Air Compressor Company (SIT) – Based in Sweden, produces gas turbines for electricity generation in industrial and petroleum applications. The efficiency spectrum of these Siemens industrial turbines ranges from 15 to 60 MW. In addition to construction, Siemens’ subsidiaries also provide long-term service and maintenance for these engineering masterpieces. In an effort to help reduce maintenance costs, Siemens is currently cooperating with the development and implementation of additive manufacturing technology using EOS technology and equipment.
This is both an opportunity and a challenge for the manufacturer, because turbine maintenance is not easy. So what is the challenge for Siemens?
Gas turbines include an air inlet, compressor, combustion chamber, turbine and hot air outlet. The air passing through the engine is compressed by a compressor. In the combustion chamber, compressed air is mixed with fuel and burned to increase the kinetic energy of the flow. In turbines, the kinetic energy of the flow is converted into mechanical energy.
This mechanical energy is used to turn the gas turbine compressor and generator (to generate electricity) or other driven equipment (e.g. compres- sor to pump the gas/oil through the pipelines). During operation the components in the engine’s hot gas path are exposed to high temperatures, at times in excess of 1,000°C (e.g. blades and vanes). This, in turn, leads to a high level of wear of the hot gas path components.
This is also true for the burner tip – the point at which the ignition of the fuel-air mixture takes place. Here, the effects of wear and tear can be clearly seen and measured. The manufacturer undertook rigorous testing to establish a prescribed operating period after which the burners typically need to be repaired.
Conventional repair processes require prefabricating large portions of the burner. This prefabricated part is used to replace the burner after the specified operating time (cut off the old set and weld on the prefabricated set). Conventional repair processes can be time consuming involving a significant number of processes and inspections. To help simplify and speed up the repair process, additive manufacturing technology has been implemented at Siemens.
What is the 3D printing solution that helps Siemens solve the above problem?
In order to meet the high demand for parts that need to be printed in gas turbines, 3D printer manufacturer creativity is required. Siemens has realized that, with EOS, not only does it have suitable accretion production technology, it also shortens production time, which can be adjusted to fit one of Siemens factories. With 3D printing system for metal EOSINT M 290 completely meets the requirements of Siemens.
The relevant changes, especially the internal scale of the machine, must be expanded to accommodate a 800 mm burner. The manufacturer also makes additional modifications to the hardware components such as camera system, optical measurement system and makes the corresponding adjustments to the software. EOS has been working on the EOSINT system extensively within a year.
From the outset, it is clear that the approach has benefited. Instead of just replacing a large portion of the burner, Siemens began by simply removing the damaged material. In addition, during the repair process, older versions of the burner may be remade according to the latest design. This means that older versions of burners can not only be repaired, but also improved – thus giving new meaning to the term Accumulated Manufacturing “.
These figures, data and facts clearly demonstrate the success of the application of 3D printing in this repair. Siemens’ plant has been successful in significantly reducing repair times, and normal operation is returning to speed quickly. This means a reduction in factory costs associated with repair and maintenance.
In addition to improving its own repair process, Siemens can now offer its customers strategic advantages: Thanks to this new process, experts can make improvements to turbine technology by integrating the components into the repair process. In this way, operators can make use of the latest technology, even if their turbines have seen years of service. Dr. Vladimir Navrotsky, Head of Technology and Innovation at Siemens Energy Service, Oil & Gas and Industrial Applications, summarizes: “with this new repair technology we are looking to carry out these high precision jobs much more quickly.”
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