Abstract: One concept of the inventors relates to a system and method in which a particulate filter comprises at least about 40% by weight of an NOx adsorbant. The filter can be used as both an NOx trap and a particulate filter. By constructing the filter elements using a substantial amount of NOx adsorbant, a large volume of NOx adsorbant can be incorporated into the particulate filter, which substantially reduces the volume and expense of an exhaust system that includes both a catalytic diesel particulate filter and an NOx trap having a large quantity of NOx adsorbant. In a preferred embodiment, the filter also oxidizes NO to NO2. In another preferred embodiment, an SCR catalyst is position downstream of the filter elements.

Abstract: One aspect of the invention relates to a process for synthesizing ammonia from hydrogen and nitrogen in which an adsorbant is provided to adsorb ammonia as it is being produced. Adsorption of the product drives the ammonia synthesis reaction and allows the process to be carried out at pressures where the gas phase equilibrium conversion is too low for a conventional system to be practical. The invention is applicable to both small and large scale ammonia synthesis. A small scale ammonia synthesis plant can be a stationary or vehicle-mounted plant used to supply reducing agent for selective catalytic reduction of NOx in diesel exhaust. Ammonia can be desorbed from the adsorbant, extracted from the adsorbant, or stored and transported in its adsorbed state.

Abstract: One aspect of the invention relates to a device for storing ammonia for use in SCR on board a vehicle. The device comprises an adsorption bed with a high capacity for storing ammonia. The device can be designed to hold a long-lasting charge of ammonia comparable to a urea tank, but will not release substantial amounts of ammonia into the environment even if the device is accidentally ruptured. In one embodiment, the devices are charged at stationary locations. In another embodiment, the devices are charged by vehicle-mounted ammonia synthesis plants. The device facilitate the use of small ammonia synthesis plants that operate at low pressures and give low conversions. Preferably, the devices are operated through temperature swing adsorption.

Abstract: The invention relates to systems for removing NOx from exhaust. In one aspect of the invention, after adsorption, an NOx adsorber is isolated from the main exhaust flow and desorption induced by raising the temperature. The desorbed NOx is combined with a reductant and reduced over a catalyst. Preferably, the reductant is syn gas produced in an on-board reformer. The catalyst need never be exposed to the main exhaust flow, which is particularly advantageous for catalysts sensitive to water, oxygen, or sulfur. In another aspect of the invention, a recirculating flow is induced through an NOx adsorber during a regeneration cycle. Recirculation can induce greater desorption at a given temperature, provide a source of heat for the adsorber, and allow a higher conversion rate with a fixed amount of catalyst. A further aspect of the invention relates to a vehicle-mounted adsorbers with provisions for heating.

Abstract: The present invention provides adsorbers with a high spatial and/or mass density of usable adsorbant in configuration suitable for vehicle exhaust systems. One aspect of the invention relates to an adsorber or catalyst having a monolith structure and porous walls. The walls have a void volume of at least about 0.1 exclusive of pores having a diameter less the 1 ?m. Another aspect of the invention relates to an adsorber or catalyst having a bed comprising porous pellets fused together to form a cohesive mass. A further aspect of the invention relates to an adsorber or catalyst having a bed comprising coated wire screens. A still further aspect of the invention relates to an adsorber or catalyst having a small number of channels, preferably just one central channel, for heating and cooling.

Abstract: The present invention comprises, without limitation, an on-board micro ammonia plant that offers a solution of NOx reduction without the hazards and inconvenience of carrying a secondary fluid on the vehicle. Thus, one embodiment of the present invention comprises a micro ammonia plant that controllably produces and stores ammonia that is used to reduce NOx levels in the exhaust streams of internal combustion engines.