Isothermal CO Converter

The process gas exiting the secondary reformer contains approximately 10-15% CO (dry gas base). In the shift conversion phase, CO is converted to CO2 and H2. In conventional plants, this conversion takes place in an adiabatic CO reactor. The conversion is conducted at two temperatures; the high temperature conversion (350-380oC) using a Fe-Cr catalyst and the low temperature conversion (200-220oC) using a Cu-Zn catalyst. After the conversion, the residual CO content of the process gas is about 0.2-0.4% (IPTS/EC, 2007 p.41).

In an isothermal reactor the conversion can be conducted in a single step at about 250oC with the use of a special copper-based catalyst (see Figure). The conversion is achieved isothermally by continuously removing heat from the catalyst bed with the use of cooling tubes (IPTS/EC, 2007 p.78). In a single step the isothermal reactor allows conversion to 0.7% CO (dry basis) (UNIDO, 1979 p.179). The heat generated from the reaction is recovered by generating medium pressure steam in a built-in heat exchanger.

This measure is applicable to all feedstock types, can also be implemented as a revamp in existing ammonia plants.

Development Status Products

Isothermal CO ConverterCosts & Benefits

Parent Process: Shift Conversion
Energy Savings Potential
CO2 Emission Reduction Potential

The investment cost for a facility with a 100,000 tonne yearly production is 500 million yen. The payback period is 0.2 years (A2A Toolkit). 

Isothermal CO ConverterSchematic

Isothermal CO Converter 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.  

Page Number: 

41, 78