The invention provides a method and a plant for producing urea ammonium nitrate (UAN). The method involves the use of a condensation section, optionally in combination with a medium pressure decomposition section, between the dissociation and neutralization sections. The invention further provides a method of modifying an existing UAN plant. The advantages of the process of the invention are that the emission of CO.sub.2 can be reduced, the plant capacity can be increased and the high capital expenditure needed for CO.sub.2 compression equipment is reduced.

Described herein is a method for detecting steady state ammonia slip for a motor vehicle having an internal combustion engine and an emissions control system. The emissions control system includes a selective catalytic reduction (SCR) device, a NOx sensor, and a controller. The controller executes a method for ammonia slip detection that includes determining if the SCR device is at steady state, comparing a NOx measurement from the NOx sensor with a predicted NOx value. If the NOx measurement exceeds the predicted NOx value by a threshold, perturbing a reductant injection, the perturbation having a selected magnitude and a selected duration. The method also includes measuring a NOx value resulting from the perturbation and computing a gradient thereof relative to the measured NOx, and ascertaining if a gradient of the NOx resulting from the perturbation exceeds a threshold and identifying a reductant slip condition if so.

Described herein is a method for detecting steady state ammonia slip for a motor vehicle having an internal combustion engine and an emissions control system. The emissions control system includes a selective catalytic reduction (SCR) device, a NOx sensor, and a controller. The controller executes a method for ammonia slip detection that includes determining if the SCR device is at steady state, comparing a NOx measurement from the NOx sensor with a predicted NOx value. If the NOx measurement exceeds the predicted NOx value by a threshold, perturbing a reductant injection, the perturbation having a selected magnitude and a selected duration. The method also includes measuring a NOx value resulting from the perturbation and computing a gradient thereof relative to the measured NOx, and ascertaining if a gradient of the NOx resulting from the perturbation exceeds a threshold and identifying a reductant slip condition if so.

Additives can be added to fertilizers to impart desirable characteristics. For example, a class of additives have been disclosed to stabilize the explosive potential of AN fertilizers are desirable, however, such additives can react with the AN fertilizer during its manufacture or during its storage. This is particularly the case where the additives contain carbonates, oxides, hydroxides, contain water of hydration or water locked within the structure (e.g. within an interlayer substructure). This reaction can be avoided if the additive has a passivation layer substantially covering the surface of the additive. The passivation layer, being substantially non-reactive and substantially insoluble, protects the additive so that the additive keeps its desired properties and the fertilizer keeps its quality. In other aspects, methods of making the fertilizer are provided.

Some embodiments of the disclosure pertain to a plant and a process for producing a urea-containing product. The plant comprises a medium pressure dissociation unit and a high pressure CO.sub.2 stripper each receiving a part of the urea synthesis solution. Stripped urea solution is further treated in a medium pressure treatment unit.

The invention relates to a process for the production of urea ammonium nitrate, a system and a method of modifying a plant. The process comprises subjecting ammonia-containing off-gas resulting from the production of ammonium nitrate (AN off-gas) to condensation under acidic conditions so as to form an acidic condensate, and using at least part of the acidic condensate as an acidic scrubbing liquid in a finishing treatment section having a gas inlet in fluid communication with a gas outlet of a finishing section of a urea production unit, wherein the finishing section is adapted to solidify urea liquid, and wherein said finishing treatment section is adapted to subject ammonia-containing off-gas of the finishing section to treatment with an acidic scrubbing liquid.

The invention relates to a process for the production of urea ammonium nitrate, a system and a method of modifying a plant. The process comprises treating ammonia-containing off-gas resulting from the production of ammonium nitrate (AN off-gas) with acidic scrubbing liquid in a finishing treatment section having a gas inlet in fluid communication with a gas outlet of a finishing section of a urea production unit, wherein the finishing section is adapted to solidify urea liquid, and wherein said finishing treatment section is adapted to subject ammonia-containing off-gas of the finishing section to treatment with an acidic scrubbing liquid.

The present invention relates to a solid, particulate, non-explosive composition comprising ammonium nitrate-based particles, in particular a fertilizer composition, of which, on the one hand, the potential misuse as a precursor for an explosive composition is limited without, on the other hand, hampering its legitimate use by farmers for food production. The solid, particulate, non-explosive composition further comprises a gelling agent which is able to form a substantially water-insoluble and non-filterable hydrogel after the solid fertilizer composition is contacted with water. The gelling agent is selected from the group of gum-based gelling agents, in particular xanthan gum-based agents and guar gum-based agents, most preferably is a xanthan gum-based agent.

The present invention relates to a solid, particulate, non-explosive composition comprising ammonium nitrate-based particles, in particular a fertilizer composition, of which, on the one hand, the potential misuse as a precursor for an explosive composition is limited without, on the other hand, hampering its legitimate use by farmers for food production. The solid, particulate, non-explosive composition further comprises a gelling agent which is able to form a substantially water-insoluble and non-filterable hydrogel after the solid fertilizer composition is contacted with water. The gelling agent is selected from the group of gum-based gelling agents, in particular xanthan gum-based agents and guar gum-based agents, most preferably is a xanthan gum-based agent.

An integrated process for the synthesis of ammonia and nitric acid, including the production of hydrogen from electrolysis of water, is controlled by a selective switching between a first mode of operation and a second mode of operation, wherein in the first mode of operation ammonia is produced in excess and is stored in a suitable ammonia storage: in the second mode of operation the ammonia from said ammonia storage is used to provide an additional input of ammonia to the production of nitric acid: the switching between said first mode and second mode is based on the amount of power which is transferred to the electrolysis of water.