The present invention relates to a method for generating ammonia from an ammonia precursor substance and to the use thereof for reducing nitrogen oxides in exhaust from industrial facilities, from combustion engines, from gas engines, from diesel engines or from petrol engines.

The present invention relates to a method for generating ammonia from an ammonia precursor substance and to the use thereof for reducing nitrogen oxides in exhaust from industrial facilities, from combustion engines, from gas engines, from diesel engines or from petrol engines.

Provided is a method for manufacturing a catalyst with which it is possible to obtain a supported metal ammonia synthesis catalyst, in which there are restrictions in terms of producing method and producing facility, and particularly large restrictions for industrial-scale producing, in a more simple manner and so that the obtained catalyst has a high activity. This method for manufacturing an ammonia synthesis catalyst includes: a first step for preparing 12CaO.7Al.sub.2O.sub.3 having a specific surface area of 5 m.sup.2/g or above; a second step for supporting a ruthenium compound on the 12CaO.7Al.sub.2O.sub.3; and a third step for performing a reduction process on the 12CaO.7Al.sub.2O.sub.3 supporting the ruthenium compound, obtained in the second step. This invention is characterized in that the reduction process is performed until the average particle diameter of the ruthenium after the reduction process has increased by at least 15% in relation to the average particle diameter of the ruthenium before the reduction process.

Provided is a method for manufacturing a catalyst with which it is possible to obtain a supported metal ammonia synthesis catalyst, in which there are restrictions in terms of producing method and producing facility, and particularly large restrictions for industrial-scale producing, in a more simple manner and so that the obtained catalyst has a high activity. This method for manufacturing an ammonia synthesis catalyst includes: a first step for preparing 12CaO.7Al.sub.2O.sub.3 having a specific surface area of 5 m.sup.2/g or above; a second step for supporting a ruthenium compound on the 12CaO.7Al.sub.2O.sub.3; and a third step for performing a reduction process on the 12CaO.7Al.sub.2O.sub.3 supporting the ruthenium compound, obtained in the second step. This invention is characterized in that the reduction process is performed until the average particle diameter of the ruthenium after the reduction process has increased by at least 15% in relation to the average particle diameter of the ruthenium before the reduction process.

An ammonia plant system upgrade utilizing both a direct and indirect multistage chilling system in the ammonia plant air compression train to increase process air flow to the secondary ammonia reformer of an existing ammonia plant as well as upgrades to provide more pre-heating along with increased process air flow.

In a process for the elimination of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) formed as by-products in the shift section (SS) of an ammonia plant, a carbon dioxide (C0.sub.2) stream from a vent line, which is arranged downstream from the shift section and the C0.sub.2 removal section, is recycled to the primary reformer (TR) of the ammonia plant. This way, the oxygenates contained in the carbon dioxide vent will be decomposed in the primary reformer burners, and the total emission of VOCs and HAPs will be considerably reduced.

In a process for the elimination of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) formed as by-products in the shift section (SS) of an ammonia plant, a carbon dioxide (C0.sub.2) stream from a vent line, which is arranged downstream from the shift section and the C0.sub.2 removal section, is recycled to the primary reformer (TR) of the ammonia plant. This way, the oxygenates contained in the carbon dioxide vent will be decomposed in the primary reformer burners, and the total emission of VOCs and HAPs will be considerably reduced.

A method for recovering waste heat in a process for the synthesis of a chemical product, particularly ammonia, where the product is used as the working fluid of a thermodynamic cycle; the waste heat is used to increase the enthalpy content of a high-pressure liquid stream of said product (11), delivered by a synthesis section (10), thus obtaining a vapor or supercritical product stream (20), and energy is recovered by expanding said vapor or supercritical stream across at least one suitable ex-pander (13); the method is particularly suited to recover the heat content of the syngas effluent after low-temperature shift.

A method for revamping an ammonia plant including a steam system, said steam system comprising at least a high-pressure section operating at a first pressure and a medium-pressure section operating at a second pressure lower than said first pressure, the revamping including: the provision of at least one additional heat recovery by means of a steam flow at a third pressure which is intermediate between said first and second pressure, and the provision of a steam export line arranged to export outside the ammonia plant at least a portion of said steam flow at said third pressure.

A method for revamping an ammonia plant including a steam system, said steam system comprising at least a high-pressure section operating at a first pressure and a medium-pressure section operating at a second pressure lower than said first pressure, the revamping including: the provision of at least one additional heat recovery by means of a steam flow at a third pressure which is intermediate between said first and second pressure, and the provision of a steam export line arranged to export outside the ammonia plant at least a portion of said steam flow at said third pressure.