With the combined resources of Siemens, the value proposition for LNG clients from the new Dresser-Rand business within Siemens Power and Gas division have expanded. Dresser-Rand’s innovations in compression technology, rotor dynamics, head capacity, and efficiency per compression section all serve to provide incremental production gains that are important to the operator. The addition of Siemens’ SGT-750 gas turbine driver and Industrial Trent® 60 aeroderivative gas turbine to the portfolio increase Dresser-Rand’s capabilities for offshore and onshore liquefied natural gas (LNG) projects.SGT-750 Low-weight Industrial Gas Turbine
The Siemens SGT-750 low-weight industrial gas turbine was designed and developed to incorporate size and weight advantages of the aero-derivative gas turbine while maintaining the robustness, flexibility and longevity of the traditional heavy-duty industrial gas turbine. With a power output of 37 MW for power generation, or of 38.2 MW for mechanical drive, the SGT-750 turbine was specifically designed for long operating times with extended overhaul intervals. It offers high reliability resulting from extremely low downtimes for planned overhaul and maintenance work (only 17 days in 17 years), and achieves the highest availability in its performance class.
The SGT-750 turbine offers easy access to all the key components. It is assembled as a unit on a single-lift frame with a divider between the turbine and the driven equipment. The SGT-750 turbine is a two-shaft machine optimized for simple cycle. It has a single, rigid rotor compressor body that is electron beam-welded to ensure reliable, stable and uniform run-up in hot or cold conditions. Axial blade attachment grooves allow blade replacement without rotor removal.
Industrial Trent 60 Aero-derivative Gas Turbine The Siemens Industrial Trent 60 aero-derivative gas turbine (ADGT) delivers up to 66 MW of electric power in simple cycle service at 42 percent efficiency. It meets the higher power and variable speed demands required by LNG operators and offers fast delivery and installation times. Renowned for its fuel economy and cost savings, the Industrial Trent 60 ADGT has already been selected by clients for an LNG onshore project as well as two floating LNG (FLNG) offshore projects since Dresser-Rand and Siemens came together.
LNGo™ Natural Gas Liquefaction System
LNG clients can combine these expanded Siemens products with Dresser-Rand’s DATUM® compressors and LNGo™ natural gas liquefaction system, the latest innovation for the LNG market. The LNGo natural gas liquefaction system uses a combination of Dresser-Rand technologies, including its MOS™ reciprocating compressor, Guascor® gas engine and Enginuity® control system in a portable, smallfootprint package that can be placed on well pads, gas flares and similar sites. The system allows for small, portable, stand-alone plants and can be moved to support changing requirements and needs.
Boil-off Gas CompressorsSiemens is the technology and market leader for cryogenic temperature boil off gas compressors for LNG production plants. With operating temperatures as low as -160 degrees Celsius (-256 degrees Fahrenheit), Siemens single shaft boil-off gas compressors (STC) are designed to withstand thermal shock and feature heavy duty dry gas seals protected in a heated seal carrier, variable inlet guide vanes for easy start up and best turndown, and an option for direct online start-up which does not require static cooling nor gas needed for flaring.
The STC boil-off gas compressor takes the evaporated gas at the storage temperature and pressure and compresses it. The compressed vapor is then cooled and expanded to re-liquefy it – or it is cooled and injected directly into a pressurized liquid stream for sale of gas.
World Class Test Facilities Thanks to the combined resources, the Dresser-Rand business comprises four world class test facilities (Duisburg, Germany; Hengelo, The Netherlands; Olean, NY, United States and LeHavre, France) that can full load test a main liquefaction train with both a driver and a compressor.Magnolia Project in Lake Charles, Louisiana Last year, four Siemens SGT-750 gas turbine drivers for the main refrigerant trains were sold to Magnolia LNG LLC for the initial two LNG trains. This scope will then be expanded into the full four-train, eight million tons per annum (mtpa) facility located in Lake Charles, Louisiana USA.
The project for LNG Limited features four mixed refrigerant Siemens STC-SV barrel-type compressors which will each be driven by a Siemens SGT-750 industrial gas turbine, while four ammonia refrigerant STC-SV compressors will each be driven by a Siemens SST-600 steam turbine. Additionally, the scope of supply includes two motor-driven feed gas booster compressors. The subsequent two LNG trains necessary to achieve the full eight mtpa for Magnolia will bring the total number of compressors to 20 at the site.
The SGT-750 industrial gas turbine driving the compressors was one of the main reasons for selecting Siemens for the project because the turbine’s power rating is a good match for the LNG train design. Its power output is more than enough for the project’s requirements, providing about an extra three MW compared to its nearest competitor, thus providing a solution that reduces project risk. The SGT-750 turbine also has lower emissions and lower operating expenditures over the plant’s lifetime, compared with the competition.
Apart from the performance of the gas turbine, an important factor in Siemens securing the contract was its ability to provide the entire LNG compression train. It enabled Magnolia LNG to bundle the entire LNG compression train through a single supplier for better support and project efficiency. This approach simplifies mechanical design, reduces interfaces for better project management, streamlines commissioning, and generally lowers overall project risks.
Installation of the LNG trains at Magnolia, expected to begin in late 2016 or early 2017, comes at an important time, and not just for the United States. There has been tremendous interest in the SGT-750 gas turbine across the industry and Magnolia will be an important demonstration of its suitability to such applications, especially in this mid-range-sized LNG facility.