# US 2017/0284256 A1 · Reducing agent injection device and exhaust gas treatment method

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- Number: US 2017/0284256 A1
- Document ID: US20170284256A1
- Status: Published application
- Kind: A1
- Application number: 15/458,070
- Filed: 2017-03-14
- Published: 2017-10-05
- Earliest claimed: 2016-03-30
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Takuya ISHIHARA; Yoshimasa OMIYA; Katsumi SAIKI
- Web page: https://patentgrep.com/patent/US20170284256A1

## CPC

- F01N 3/2066: {Selective catalytic reduction [SCR]}
- B01D 53/90: Injecting reactants
- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 53/9431: {Processes characterised by a specific device}
- F01N 3/2026: {directly electrifying the catalyst substrate, i.e. heating the electrically conductive catalyst substrate by joule effect}
- B01D 2251/2062: Ammonia
- B01D 2251/2067: Urea
- B01D 2255/20723: Vanadium
- B01D 2255/20761: Copper
- B01D 2255/2092: Aluminium
- B01D 2255/50: Zeolites
- B01D 2255/808: Hydrolytic
- B01D 2255/904: Multiple catalysts
- B01D 2257/404: Nitrogen oxides other than dinitrogen oxide
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- F01N 3/2842: {specially adapted for monolithic supports, e.g. of honeycomb type (F01N3/2853 - F01N3/2871 take precedence)}
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/1453: Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
- Y02T 10/12: Improving ICE efficiencies
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A reducing agent injection device includes a honeycomb structure and a urea spraying device spraying a urea water solution in mist form. A pair of electrode members is formed in the honeycomb structure. The honeycomb structure of the reducing agent injection device, the hydraulic diameter HD, defined as HD=4×S/C, when the area of the cross section of one of the cells in the cross section perpendicular to the cell extending direction is S, and the peripheral length of the cross section of one of the cells is C, is 0.8 to 2.0 mm. Also, the open frontal area OFA of the honeycomb structure in the cross section perpendicular to the cell extending direction is 45 to 80%.

## Claims

### Claim 1

A reducing agent injection device, comprising:
a honeycomb structure that has a pillar-shaped honeycomb structure body having partition walls defining and forming a plurality of cells which is through channels of a fluid and extends from a first end face being an end face on an inflow side of the fluid to a second end face being an end face on an outflow side of the fluid, and that has at least a pair of electrode members arranged in a side surface of the honeycomb structure body; and
a urea spraying device that sprays a urea water solution in mist form,
wherein each of the pair of electrode members is formed in a band shape extending to a cell extending direction of the honeycomb structure body, and one electrode member of the pair of electrode members is arranged on an opposite side of the other electrode member of the pair of electrode members with respect to a center of the honeycomb structure body sandwiched by the pair of electrode members, in the cross section perpendicular to the cell extending direction,
the hydraulic diameter HD, defined as HD=4 ×S/C, when the area of the cross section of one of the cells in the cross section perpendicular to the cell extending direction is S, and the peripheral length of the cross section of one of the cells is C, is 0.8 to 2.0 mm,
the open frontal area OFA of the honeycomb structure in the cross section perpendicular to the cell extending direction is 45 to 80%, and
the urea water solution sprayed from the urea spraying device is supplied into the cells from the first end face of the honeycomb structure body, and urea in the urea water solution supplied into the cells is heated and hydrolyzed in the electrically heated honeycomb structure body to generate ammonia, and the ammonia is discharged outside the honeycomb structure body from the second end face and is injected outside.

### Claim 2 (depends on 1)

An exhaust gas treatment device, comprising:
an exhaust pipe that flows an exhaust gas containing NOx;
the reducing agent injection device as defined in claim 1 that injects the ammonia into the exhaust pipe; and
an SCR catalyst arranged on a downstream side of the exhaust pipe with respect to a position where the ammonia is injected.