How an upgrade to a gas turbine fleet has added 5 GW to Iran’s power capacity

WWith 180 units operating across the country, V94.2 is the largest turbine fleet currently active in Iran’s power sector.

Considering its significant share in Iran’s turbine market, even minor improvements in V94.2’s performance will bring substantial benefits for the nation’s power grid, such as increasing its overall capacity and boosting the grid’s efficiency.

The V94.2 family has long been a favourite choice of Iran’s power sector due to its reliability, accessibility, high output, domestic manufacturing and services and low investment cost.

Iran’s growing economy and its rising power demand, the push for rehabilitation and renovation of national infrastructure and environmental commitments, such lower fuel consumption and lower carbon footprint in line with the COP21 agreement, are factors that have encouraged Iranian power plant developer MAPNA Group’s executives to opt for long-term investment in the gas turbine.

This was combined with MAPNA’s strategy to develop homegrown technology and boost its competitive advantage domestically and internationally.

he first steps to upgrade the V94.2 were taken in 2011 under an R&D scheme dubbed MAP2+. The project focused on modification of the mechanical design and combustion elements of the turbine to improve its efficiency and gross output. The final product, called MGT-70(1), boasted an output of 166 MW and an efficiency rate of 34.5 percent.

The project was then redefined in a broader scope under the title MAP2B. Before developing the final product of MAP2B, an in-between version, MGT-70(2), was introduced in 2013, with slightly increased combustion temperature, modified hot gas path, improved performance of cooling, and an output of 170 MW.

MGT-70(2) was put into operation in the MAPNA-owned 954 MW Assaluyeh power plant in 2013.

Throughout the last phase of the MAP2B project, Unit 6 of the Parand combined-cycle power plant, located 30 km south of Tehran, was turned into an advanced laboratory named MAP-Lab for prototype testing as well as future research activities.

Special advanced measuring equipment which gathers a large volume of data from the machine, analyzed by MAPNA engineers, were used in the tests.

MGT-70(3) tests were finally carried out in late June 2017, in +40°C temperature, in circumstances which allowed reliable

monitoring of various parameters such as compressor stability.

Thanks to cutting-edge design, gross output has increased from 157 MW in the V94.2 version 3 to 185 MW in MGT-70(3) at ISO conditions, while its efficiency has reached over 36.4 per cent with a significant 2 per cent leap. A mere 15°C reduction in combustion degree, which only slightly decreases output and efficiency, can stretch the span between two successive overhaul operations for an additional 8000 hours, increasing the lifetime of the turbine.

These advantages were gained through a full 3D redesign of compressor blade and vane airfoils; full 3D redesign of turbine blade and vane airfoils; redesign of cooling and heat transfer of turbine blades and vanes; redesign of turbine secondary air system (sealing and cooling); redesign of journal-thrust bearing; new base material for all turbine blades and the first four stages of compressor, and advanced coating for hot gas path.

Not only has MAPNA enhanced the performance of the gas turbine, but it has also developed additional packages for gas turbines and combined-cycles to improve performance, flexibility and reliability. A triplepressure steam cycle which employs an MGT-70(3) gas turbine reaches to 54 per cent efficiency for the E-Class plant.

Supporting the national grid

Upgrading the 180 units of V94.2 turbines operating across Iran and converting them into the MGT-70(3) version could add over 5 GW to the country’s current electric power capacity.

There are also other advantages to this conversion campaign. For example, a massive amount of fuel can be saved due to significant efficiency increases.

This substantial drop in fuel consumption and expenses translates into a sharp cut in carbon emissions for each upgraded unit in compliance with Iran’s environmental commitments under the 2016 Paris Agreement.

Other advantages of the new MAPNA product include extended lifetime, guaranteed services and spare parts for long-term operation, uprated electrical generator, additional control features to attain maximum output, and saving the budget allocated to construction of new power plants.

The new product found a home quite early, with installation in the 3 GW combined-cycle power plant which is being constructed by MAPNA Group in Rumaila, near Basra in southern Iraq.

Currently, two units of MGT 70(3) are under installation at Rumaila plant, while six other service upgraded units have been commissioned and delivered to Iranian customers.