Exhaust Gas Treatment
First Claim
1. A unitary device for generating and feeding gaseous hydrolysis product comprising ammonia, formed by the hydrolysis of an aqueous solution of urea (as hereinbefore defined) at elevated temperature and pressure, into the exhaust gas of an IC engine as it flows through the exhaust system of the engine to an SCR catalyst, the device being adapted to be placed in the exhaust system so that the exhaust gas will flow through it during use, and comprisinga) a housing having an inlet for the exhaust gas and an outlet for the exhaust gas;
- b) a reaction vessel located at least partially within the housing between the inlet and the outlet for containing an aqueous solution of urea and arranged such that, in use, the vessel and therefore the urea solution become heated by means of heat exchange with the exhaust gas as it flows from the inlet to the outlet;
c) a urea solution inlet to the reaction vessel and a gaseous hydrolysis product outlet from the reaction vessel;
d) a reservoir for receiving and storing gaseous hydrolysis product;
e) a valve in the outlet from the reaction vessel and adapted to permit the contents of the reaction vessel, in use, to attain an elevated pressure as it becomes heated, and periodically to discharge gaseous hydrolysis product into the reservoir; and
f) a conduit for interconnecting the reservoir and the exhaust system, the conduit including a valve to selectively control the feed of hydrolysis product stored in the reservoir into the exhaust gas via the conduit.
1 Assignment
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Accused Products
Abstract
A device 1, capable of being placed in-line in the exhaust conduit of an IC engine upstream of an SCR catalyst, which produces a gaseous hydrolysis product, containing ammonia, which is added to the exhaust gas in a controlled manner to pass therewith through the SCR catalyst to reduce the NOx content of the exhaust gas. The device 1 has an inlet 2 and an outlet 3 for the exhaust gas flowing therethrough and comprises an outer body 4, which forms a pressure barrier, and passing through the outer body 4 is an inner body 5 which comprises a flowpath longitudinally therethrough from the inlet 2 to the outlet 3. The device 1 is split into two sections, a reactor section with an inlet for pressurised aqueous urea and comprising an upper and lower area connected by a plurality of tubes 10 which pass through the exhaust gas for heat exchange and wherein the hydrolysis of urea occurs at elevated temperature and pressure and a reservoir section connected to the reactor section via a pressure release valve to allow the gaseous hydrolysis product to pass from the reactor to the reservoir. The device further comprises a valve 17 for dosing the gaseous hydrolysis product into the exhaust gas.
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Citations
70 Claims
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1. A unitary device for generating and feeding gaseous hydrolysis product comprising ammonia, formed by the hydrolysis of an aqueous solution of urea (as hereinbefore defined) at elevated temperature and pressure, into the exhaust gas of an IC engine as it flows through the exhaust system of the engine to an SCR catalyst, the device being adapted to be placed in the exhaust system so that the exhaust gas will flow through it during use, and comprising
a) a housing having an inlet for the exhaust gas and an outlet for the exhaust gas; -
b) a reaction vessel located at least partially within the housing between the inlet and the outlet for containing an aqueous solution of urea and arranged such that, in use, the vessel and therefore the urea solution become heated by means of heat exchange with the exhaust gas as it flows from the inlet to the outlet; c) a urea solution inlet to the reaction vessel and a gaseous hydrolysis product outlet from the reaction vessel; d) a reservoir for receiving and storing gaseous hydrolysis product; e) a valve in the outlet from the reaction vessel and adapted to permit the contents of the reaction vessel, in use, to attain an elevated pressure as it becomes heated, and periodically to discharge gaseous hydrolysis product into the reservoir; and f) a conduit for interconnecting the reservoir and the exhaust system, the conduit including a valve to selectively control the feed of hydrolysis product stored in the reservoir into the exhaust gas via the conduit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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- 47. A hydrolysis gas reservoir for receiving ammonia containing gas from a hydrolysis reaction vessel, the reservoir comprising a body and a manifold, said manifold having passageways therein to accommodate various sensors and at least one valve and having heating means associated therewith to maintain said manifold at an elevated temperature.
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60. A system for the reduction of NOx in the exhaust gas of an IC engine comprising a reactor for producing ammonia, a reservoir to temporarily store ammonia a means of introducing ammonia to the exhaust gas and an SCR catalyst, the reservoir including
a body and a manifold, said manifold having passageways therein to accommodate various sensors and at least one valve and having heating means associated therewith to maintain said manifold at an elevated temperature.
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61. A device for generating gaseous hydrolysis product comprising ammonia, formed by the hydrolysis of an aqueous solution of urea at elevated temperature and pressure, the device being adapted to be placed in the exhaust system so that the exhaust gas will flow through it during use, and comprising
a) a first substantially upright and cylindrical tube enclosed at its upper end and open at its lower end and having an inlet and an outlet on its sides for the exhaust gas; -
b) an elongate reaction vessel located in the tube for containing an aqueous solution of urea and arranged such that, in use, the vessel and therefore the urea solution become heated by means of heat exchange with the exhaust gas as it flows from the inlet to the outlet; and c) a urea solution inlet to the reaction vessel and a gaseous hydrolysis product outlet from the reaction vessel; wherein said reaction vessel is attached to the upper enclosed end of the first tube and sealingly engages with the first tube at its lower end preventing the exhaust gas from escaping out of the open lower end of the first tube. - View Dependent Claims (62, 63, 64, 65, 66, 67, 68, 69, 70)
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Specification