首页> 外国专利> Reducing emissions of nitrogen oxide(s) from lean-burn engine with associated exhaust system - by feeding aqueous urea solution from storage vessel through line to injector, returning solution to storage vessel, injecting solution into exhaust gases and passing gas to selective catalytic reduction reactor

Reducing emissions of nitrogen oxide(s) from lean-burn engine with associated exhaust system - by feeding aqueous urea solution from storage vessel through line to injector, returning solution to storage vessel, injecting solution into exhaust gases and passing gas to selective catalytic reduction reactor

机译：减少带有相关排气系统的稀薄燃烧发动机的氮氧化物排放-通过将尿素水溶液从存储容器通过管线输送到喷射器，将溶液返回存储容器，将溶液喷射到排气中并将气体传递到选择性催化还原反应器

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摘要

A method for reducing the emissions of NOx from a lean-burn engine with an associated exhaust system, including an exhaust passage linked to a reactor effective for selective catalytic NOx reduction, comprises feeding an aqueous urea solution from a storage vessel through a line to an injector; returning the urea solution from the injector to the storage vessel, the rates of feed and return being sufficient to supply urea as needed to the exhaust gases and maintain the temperature of the urea solution sufficiently low that it is not permitted sufficient time at elevated pressure to hydrolyse the urea to such an extent that solids precipitate; injecting the urea solution into the exhaust gases at a temperature sufficient for selective catalytic reaction (SCR); and passing the exhaust gas through the SCR reactor. Also claimed are: (i) a method in which a heat exchange fluid is passed in heat exchange contact with the line and/or injector, but otherwise the same as above; and (ii ) an apparatus for reducing the emissions of NOx from a lean-burn engine with an associated exhaust system, including an exhaust passage linked to a reactor effective for selective catalytic NOx reduction, comprising means for feeding an aqueous urea solution form a storage vessel through a line to an injector; means for returning the solution to the storage vessel, means for injecting the solution into the exhaust gas and exhaust passage means leading from the injector to an SCR reactor. Preferably the urea solution contains at least 25 wt.% urea. The temperature of the exhaust gases is 180-650 [deg]C. The urea solution is maintained at less than 140 [deg]C. The urea solution is injected into the exhaust gases at at least 30 psi. The urea solution is heated in whole or in part by an auxiliary heating means or by heat transfer from the exhaust. The urea solution is introduced into the exhaust between exhaust valves of the engine and a turbocharger exhaust turbine. The urea is introduced into the exhaust close-coupled relation with the SCR catalyst. Introduction of the urea solution into the exhaust is controlled by a controller integrated with an engine management system. The temperature of the urea solution is allowed to rise above 100 [deg]C and the solution is maintained at a pressure above the saturation vapour pressure of the temperature of the solution.

机译：一种用于减少带有相关排气系统的稀燃发动机的NOx排放的方法，该方法包括与有效用于选择性催化NOx还原的反应器相连的排气通道，该方法包括将尿素水溶液从储罐经管线输送到燃烧室。注射器;将尿素溶液从喷射器返回到储存容器，进料和回流的速度足以将所需的尿素供应到废气中，并保持尿素溶液的温度足够低，以至于不允许在高压下有足够的时间达到将尿素水解至固体沉淀的程度;在足以进行选择性催化反应（SCR）的温度下将尿素溶液注入废气中;使废气通过SCR反应器。还要求保护：（i）使热交换流体与管线和/或喷射器热交换接触地通过的方法，但与上述方法相同; （ii）具有相关排气系统的用于减少稀燃发动机的NO x排放的设备，其包括与有效选择性催化还原NO x的反应器相连的排气通道，其包括将尿素水溶液从存储装置中供给的装置。容器通过管线到达注入器;用于将溶液返回到储存容器的装置，用于将溶液注入废气中的装置，以及从喷射器通向SCR反应器的排气通道装置。优选地，尿素溶液包含至少25重量％的尿素。废气的温度为180-650℃。尿素溶液保持在小于140℃。将尿素溶液以至少30 psi的压力注入废气中。尿素溶液通过辅助加热装置或通过废气的热传递全部或部分加热。尿素溶液被引入到发动机的排气门和涡轮增压器排气涡轮之间的排气中。尿素与SCR催化剂被引入排气紧密耦合关系。将尿素溶液引入废气中是由与发动机管理系统集成的控制器控制的。使尿素溶液的温度升高至高于100℃，并将溶液保持在高于溶液温度的饱和蒸气压的压力下。

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公开/公告号DE29825250U1

专利类型
公开/公告日2007-03-22

原文格式PDF
申请/专利权人 CLEAN DIESEL TECHNOLOGIES INC.;
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申请/专利号DE1998225250U
发明设计人
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申请日1998-03-31
分类号F01N3/20;B01D53/60;B01D53/94;
国家 DE
入库时间 2022-08-21 20:28:49

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