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New Mobile Gas Turbine with a Wide Range of Applications PUBLIC ACCESS

 

[+] Author Notes
Uwe Schütz

Siemens Schweiz AG

Mechanical Engineering 140(03), S54-S55 (Mar 01, 2018) (2 pages) Paper No: ME-18-MAR9; doi: 10.1115/1.2018-MAR-9

This article describes features and advantages of new mobile gas turbine with a wide range of applications. The market for mobile gas turbines is continuously growing. Mobile units are also an ideal choice when it comes to making large power capacities available on a short-term basis, for example, for major events, prolonged downtimes at other power stations, or power-intensive applications such as mining or shale gas extraction. If the electricity requirements exceed the level that can normally be demanded of a mobile application, an SGT-A45 installation can be modified to form a combined-cycle power plant to further improve its efficiency. In remote locations, this can be achieved using an Organic Rankine Cycle (ORC), to eliminate the need for water and water treatment systems, and to optimize energy recovery from the SGT-A45 off-gas stream at a relatively low temperature. The use of a direct heat exchanger, in which the ORC working fluid is evaporated by the off-gas stream from the gas turbine, can boost the system’s output capacity by more than 20 percent.

The energy industry is undergoing a rapid process of change.

In many regions, the infrastructure necessary for power supply is coming under pressure due to the constant growth in demand for electricity. By 2040, according to the International Energy Agency, global energy requirements could increase by 30 percent, while there are still more than a billion people without electrical power. At the same time, renewable energies are playing an important role but continue to require backup due to the fluctuating power supply. In this situation, mobile units that can provide fast, flexible, reliable electricity are growing in significance.

That's why, since about 2010 more and more uses have been found for mobile gas turbines, whose ability to make electricity available as quickly as possible is a critical advantage.

A range of economic, environmental, and technological factors have led to an expansion in decentralized, distributed electricity generation. These factors were based on economic growth in developing regions, as well as difficulties in financing, approval, and operation of large, central power stations. Power plants based on mobile gas turbine technology have benefited from these developments. They can be installed quickly and can thus be connected to the grid swiftly. Their growth was driven by the increase in the requirement for electrification in parts of the world experiencing rapid development. This is where mobile gas turbines offer an attractive solution thanks to their “plug-and-play” design that lets them start feeding electricity into the grid in just a few weeks. Mobile gas turbines therefore serve as a bridging technology that brings the set-up times needed for higher capacities into line with the high level of demand.

The market for mobile gas turbines is continuously growing. The bulk of this market is currently served by products in the 30 MW class based on technology from the aircraft industry. They offer a range of features that suit for the applications described above:

  • High power density;
  • Compact unit construction, minimal installation requirements;
  • Operation using gas and liquid fuel;
  • Particularly flexible operation;
  • Suitability for 50 or 60-Hz frequencies with minimal adjustment to configuration;
  • Ability to operate under tough conditions.

In recent years, the market for mobile gas turbines in the 30 MW class using technology from the aircraft industry has averaged over $1 billion p.a. for new units alone. That represents around 40% of the total market for gas turbines in this capacity range.

Many factors are contributing to the urgent demand for electricity. These include economic growth; damaged or unreliable infrastructure; market changes through liberalization and the expansion of renewables; and short-term needs for additional electricity. A growing population, higher standards of living, and development of the industrial sector are drivers of increased demand for electricity. Mobile units are an ideal solution in cases like these, when large volumes of electricity have to be supplied in a short period.

An unplanned outage at a power station can significantly impact on the power supply, and in a worst-case scenario can lead to electricity outages. In these cases, too, establishing a replacement supply is an urgent necessity. The necessary corrective action must often be performed in locations that are quite difficult to access - and since mobile gas turbines can provide rapid grid support in multiple locations, they provide a solution here and can also help cover seasonal peaks.

The transformation towards renewables necessitates a greater level of flexibility in implementing the mobile design of gas turbines and their ability to adapt to aspects such as operating cycles, fuel supplies, and environmental conditions. Mobile units are also an ideal choice when it comes to making large power capacities available on a short-term basis, e.g. for major events, prolonged downtimes at other power stations, or power-intensive applications such as mining or shale gas extraction.

In view of the requirements described above, the market for mobile gas turbines has been concentrated mainly in regions with a less developed infrastructure or experiencing rapid economic growth. From 1999 to 2016, therefore, the Middle East and North Africa accounted for the largest market share for mobile gas turbines (35%), followed by Latin America (21%) and Asia-Pacific (18%). In the shorter term, regions like sub-Saharan Africa and additional parts of Asia-Pacific will follow this trend. This is the situation in which Siemens has developed its new SGT-A45 mobile gas turbine unit, which provides a generating capacity of up to 44 MWel, is suited for 50 and 60-Hz networks, and can run on gas or liquid fuels. The turbine is based on Rolls-Royce Aero-Engine technology and achieves efficiency levels of up to 40.4%. It has a higher generating capacity than any other gas turbine in its class, while being highly efficient and flexible. It also has all the properties for swift delivery and installation in just two weeks or less. Its compact design makes it easier to transport quickly - whether to its first installation site or to a new location. The turbine and its auxiliary units are mounted on three trailers to ensure optimized mobility: dimensions, weight and the connections between the trailers are reduced to a minimum. Most of the commissioning work is done before the unit leaves the factory, which reduces the time and cost of installation on-site.

If the electricity requirements exceed the level that can normally be demanded of a mobile application, an SGT-A45 installation can be modified to form a combined-cycle power plant to further improve its efficiency. In remote locations, this can be achieved using an Organic Rankine Cycle (ORC), to eliminate the need for water and water treatment systems, and to optimize energy recovery from the SGT-A45 off-gas stream at a relatively low temperature. The use of a direct heat exchanger in which the ORC working fluid is evaporated by the off-gas stream from the gas turbine can boost the system's output capacity by more than 20%.

Copyright © 2018 by ASME
Topics: Gas turbines
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