Increasing Mixed Feed Preheat Temperature

About half of the heat released by the burners is utilized by the reformer tubes. The remaining heat is carried by the flue gases that leave the radiant section of the reformer and is recovered by the convection coils to preheat other process streams (IPTS/EC, 2007 p.40). When the flue gas temperature is considerably reduced, the flue gases are released into the atmosphere. 

The heat requirements of the radiant section determine the overall fuel consumption of the furnace. By decreasing the duty of the radiant section by extended preheating of the reformer feed gas before it reaches the catalyst tubes, the overall fuel consumption can be decreased (OPET Network, 1998). 

As the fuel gas for the primary reformer burners is typically supplied to the ammonia plant battery limits at close to or below ambient temperature, heating this stream with low level heat recovery from the coolest portion of the reformer convection zone represents a particular option. In India, preheater for reformer fuel gas has been installed in four plants (FAI, 2013).

Redesigning the convection section will typically result in lower steam generation. Therefore, to optimize the energy efficiency improvements, this concept will have to be combined with a reduction in steam consumption (i.e. lower steam/carbon ratio, improved efficiency steam turbine) (A2A Toolkit).  

Development Status Products

Increasing Mixed Feed Preheat TemperatureCosts & Benefits

Parent Process: Steam Reforming
Energy Savings Potential
CO2 Emission Reduction Potential

Indian Flag For a 1 500 tpd plant, an investment in the range of US $ 500 000 is required to preheat fuel gas using low grade recovered heat (FAI, 2013)..

Increasing Mixed Feed Preheat Temperature Publications

Increasing Mixed Feed Preheat Temperature 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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Increasing Mixed Feed Preheat Temperature Tools

Assessment to Action (A2A) Toolkit

Developed by IIP, in collaboration with energy expertsat ICF Marbek, members of the IFA and experts in China, the A2A (Assessment to Action) Toolkit is a free suite of resources on energy management and technology best practices created for ammonia companies. The A2A Toolkit provides a first-order, high-level assessment to identify and prioritize energy efficiency opportunities. It does so by drawing on various assessment modules on technical best practices, management best practices (based on ISO 50001 standard) and productivity improvements.