First application of Uhde’s dual pressure ammonia process for revamping of the Duslo ammonia plant


Duslo operates an Uhde ammonia plant at Šal'a, Slovak Republic. In 2004 Duslo decided to increase the ammonia production capacity and optimise the energy consumption for the total ammonia production at Šal'a. Uhde provided the basic engineering for the capacity upgrade of the ammonia plant by applying their dual pressure ammonia process.

The front end of the plant will be upgraded by Uhde’s latest reformer technology using reformer tubes with increased diameter with state of the art metallurgy and Uhde’s latest secondary reformer design.

Process air compressor will be upgraded by a turbine driven parallel machine. CO2 removal system capacity will be increased using UOP ‘s Benfield ACT-1 process.

Synthesis gas compression is upgraded for the first 3 stages of the existing compressor by a parallel turbo compressor. Synthesis gas drying will be applied downstream the 3rd stage of the compressor.

The dual pressure ammonia process features Uhde’s OT-Synthesis operating at approx. 135 bar and the original Uhde High pressure Synthesis which Duslo operates successfully since 1973. A 2 bed radial ammonia converter will be applied in the OT-Synthesis. Synthesis gas from the OT-Synthesis is fed to the suction of the 4th stage of the existing synthesis gas compressor and subsequently fed to the existing high pressure loop. Thus the changes to existing H. P. equipment are minimised.

The revamp measures for the front end have been started in the annual Shutdown in 2005 and will be continued throughout 2006. Independently from the operation of the existing plant the OT-Synthesis will be installed and commissioning is scheduled for 2007.


Fred Kessler

Dirk Hoberg

Stefan Hrubý

Uhde GmbH, Germany

Duslo, a.s., Šal'a, Slovakia

Presented at:

Nitrogen 2006 Conference & Exhibition, Vienna, Austria, March 12-15, 2006

The Uhde Dual Pressure Process - Reliability issues and scale up considerations

Uhde dual-pressure process for large-scale ammonia plants

AIChE Ammonia Safety Symposium 2013

Methanol Emission from Ammonia Plants and its Reduction

Nitrogen + Syngas 2013

Development of equipment design tools from experimental data using the example of autothermal reforming

Nitrogen + Syngas 2012

Comparison of synthesis gas generation concepts for capacity enlargements of ammonia plants

AIChE Ammonia Safety Symposium 2012

Ammonia Plant Capacity Increase by Autothermal Reforming and Dual Pressure Synthesis

Nitrogen + Syngas 2011

Low Energy Consumption Ammonia Production: Baseline Energy Consumption, Options for Energy Optimization

Nitrogen + Syngas 2010

Autothermal reforming: a flexible syngas route with future potential

AIChE Ammonia Safety Symposium 2005

4000 mtpd ammonia plant based on proven technology