Retrofitting Steam Turbines for Higher Efficiency

In general, all the high pressure steam generated in the ammonia plant is fed to steam turbines that drive the synthesis compressor. At an intermediate pressure level, a part of the steam is extracted from the turbine and is used to supply the process steam in the reformer and to drive other compressors, fans and pumps. The rest of the steam is condensed (IPTS/EC, 2007 p.43).

In recent decades, the technology of steam turbines has improved significantly (materials, blade types, new designs for rotors and stationary parts, integration). Older steam turbines may be retrofitted to enhance their performance. The retrofit would lead to an increase in the power rating of the steam turbine reducing the steam rate and reducing energy use. 

Development Status Products

Retrofitting Steam Turbines for Higher EfficiencyCosts & Benefits

Parent Process: General Measures for Ammonia Plants
Energy Savings Potential
CO2 Emission Reduction Potential

The payback time of the steam turbine upgrade is usually in the order of 1 year. Costs can be reduced by including the upgrade in the normal turn-around schedule. The cost for upgrading two back-pressure turbines with more efficient condensing turbines in an ammonia plant in the US estimated to require an investment of $ 1.2 million (U.S. DOE, 2007)

Retrofitting Steam Turbines for Higher Efficiency Reference Documents

Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals - Ammonia, Acids and Fertilisers

Prepared by the Institute for Prospective Technical Studies of European Commision, this document provides detalied information on Best Available Technologies applicable to Ammonia production – as well as on the production of Acids and Fertilizers.  

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