EXHAUST GAS TREATMENT SYSTEM WITH UPSTREAM SCR CATALYST

A system for treatment of an exhaust gas stream from an engine is provided, containing an upstream selective catalytic reduction (SCR) catalyst, which receives the exhaust gas stream without any intervening catalyst, a diesel oxidation catalyst (DOC) positioned downstream thereof; a catalyzed soot filter (CSF) downstream of the diesel oxidation catalyst; a second SCR catalyst positioned downstreamof the catalyzed soot filter; and an ammonia oxidation (AMOx) catalyst. The application also describes use of such systems to reduce nitrogen oxides (NOx) and hydrocarbons (HC) in an exhaust gas stream. 提供了一种用于处理来自发动机的排气流的系统，所述系统包含：上游选择性催化还原(SCR)催化剂，所述上游SCR催化剂在没有任何中间催化剂的情况下接收所述排气流；柴油氧化催化剂(DOC)，所述DOC定位在所述上游SCR催化剂下游；催化型烟灰过滤器(CSF)，所述CSF定位在所述柴油氧化催化剂下游；第二SCR催化剂，所述第二SCR催化剂定位在所述催化型烟灰过滤器下游；以及氨氧化(AMOx)催化剂。本申请还描述了使用此类系统以还原排气流中的氮氧化物(NOx)和碳氢化合物(HC)。