By Joseph BAMIDELE

Siemens, one of the world’s leading power systems company has concluded plans to make its industrial steam turbines more efficient and more flexible.

The upgrade is based on an improved design that increases the efficiency of the turbines by up to two percentage points. In addition, the redesigned turbines can be started up much more quickly – in the best case, in only half the time that was previously needed.

With the improved turbines, biogas plants, combined gas and steam turbine generating plants, and smaller coal-fired power plants can produce more electricity than before from the same amount of primary energy. In industrial plants the new turbines can be used to utilize the waste heat even more efficiently.

Plants that don’t produce electricity continuously, such as solar thermal power plants, reap extra benefits from the much shorter warm-up times.

The design combines a variety of concepts from the existing Siemens turbine families and in effect brings together the best individual solutions. The most important factor responsible for the increase in efficiency is the optimized shape of the turbine blades. There has also been an improvement in the seals between the individual turbine stages, so that as much steam as possible reaches the blade wheels and contributes to the generation of electricity.
One important improvement is a reduction of the warm-up times needed to bring the turbine to a uniform operating temperature. During this start-up period, no mechanical stresses resulting from different rates of thermal expansion in individual parts can be tolerated. Depending on the turbine type and the field conditions, the warm-up time of an industrial steam turbine can last from a few minutes to several hours.

The new turbines have a symmetrically structured outer casing that heats up more uniformly than before. They are also more lightweight and warm up faster. These improvements were achieved through the use of new materials and a design that makes do with less material overall. The improved warm-up behavior reduces mechanical stress during the start-up and shut-down phases and thereby extends the service life of the turbine. The new “Enhanced Platform Design” is the foundation of the coming generation of industrial steam turbines. Siemens is introducing this design step by step for turbines with outputs between 15 and 250 megawatts.

Siemens AG (Berlin and Munich) is a global powerhouse in electronics and electrical engineering, operating in the fields of industry, energy and healthcare as well as providing infrastructure solutions, primarily for cities and metropolitan areas. For over 160 years, Siemens has stood for technological excellence, innovation, quality, reliability and internationality.

The company is the world’s largest provider of environmental technologies. Around 40 percent of its total revenue stems from green products and solutions. In fiscal 2011, which ended on September 30, 2011, revenue from continuing operations totalled €73.5 billion and income from continuing operations €7.0 billion. At the end of September 2011, Siemens had around 360,000 employees worldwide on the basis of continuing operations.