# US 7,744,837 B2 · Reducing Agent Composition

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- Number: US 7,744,837 B2
- Document ID: US7744837B2
- Status: Granted
- Kind: B2
- Application number: 11/573,160
- Filed: 2005-08-03
- Published: 2009-01-08
- Granted: 2010-06-29
- Earliest claimed: 2004-08-04
- Assignees: Kemira Oyj
- Inventors: Timo Nissinen; Timo Härmä; Jari-Jukka Kukkonen
- Web page: https://patentgrep.com/patent/US7744837B2

## CPC

- F01N 3/2066: {Selective catalytic reduction [SCR]}
- B01D 53/9436: {Ammonia}
- B01D 2251/2067: Urea
- B01D 2257/404: Nitrogen oxides other than dinitrogen oxide
- F01N 2570/14: Nitrogen oxides
- F01N 2610/02: the substance being ammonia or urea
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- 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)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

The invention relates to a reducing agent composition for use in the catalytic reduction process of nitrogen oxides in exhaust gases, the composition containing 20-40 w % of urea, 19-40 w % of ammonium formate, and water.

## Claims

### Claim 1

A reducing agent composition to be added to the catalytic reduction process of nitrogen oxides from the exhaust gases, characterised in that the reducing agent composition comprises 20-40% of urea calculated on the weight of the composition, 20-40% of ammonium formate calculated on the weight of the composition, and water.

### Claim 2 (depends on 1)

A composition as defined in claim 1, comprising 25-40% of urea calculated on the weight of the composition.

### Claim 3 (depends on 1)

A composition as defined in claim 1, comprising 30-35% of urea calculated on the weight of the composition.

### Claim 4 (depends on 1)

A composition as defined in claim 1, containing 25-40% of ammonium formate calculated on the weight of the composition.

### Claim 5 (depends on 4)

A composition as defined in claim 4, containing 30-35% of ammonium formate calculated on the weight of the composition.

### Claim 6 (depends on 1)

A composition as defined in any of claim 1, which provides ammonia to the reduction process in an amount exceeding 0.18 kg/kg of the composition.

### Claim 7 (depends on 1)

A composition as defined in claim 1, which provides ammonia to the reduction process in an amount exceeding 0.21 kg/kg of the composition.

### Claim 8 (depends on 7)

A composition as defined in claim 7, which provides ammonia to the reduction process in an amount exceeding 0.24 kg/kg of the composition.

### Claim 9 (depends on 1)

A composition as defined in claim 1, wherein the composition is added to a selective catalytic reduction process.

### Claim 10 (depends on 1)

A composition as defined claim 1, further comprising an anti-corrosive agent.

### Claim 11

A method for the selective catalytic reduction of nitrogen oxides in an exhaust gas, comprising supplying to an selective catalytic reduction catalyst in an exhaust gas line a reducing agent composition comprising 20-40% of urea calculated on the weight of the composition, 20-40% of ammonium formate calculated on the weight of the composition, and water.

### Claim 12 (depends on 11)

The method as defined in claim 11, wherein the selective catalytic reduction of nitrogen oxides is in an exhaust gas from a diesel vehicle.

### Claim 13 (depends on 11)

The method as defined in claim 11, wherein the selective catalytic reduction of nitrogen oxides is in an exhaust gas from a light vehicle, a heavy-duty vehicle, a power tool, or a ship.

### Claim 14 (depends on 13)

The method as defined in claim 13, wherein the selective catalytic reduction of nitrogen oxides is in an exhaust gas from a light vehicle.

### Claim 15 (depends on 11)

The method as defined in claim 11, wherein the selective catalytic reduction process has a maximum temperature of 700° C.

### Claim 16 (depends on 15)

The method as defined in claim 15, wherein the selective catalytic reduction process has a minimum temperature of 120° C.

### Claim 17 (depends on 1)

A method for reducing the volume of a reducing agent tank, comprising supplying to a selective catalytic reduction catalyst in an exhaust gas line the reducing agent composition of claim 1.

### Claim 18 (depends on 1)

A method for increasing the filling intervals of a reducing tank, comprising supplying to a selective catalytic reduction catalyst in an exhaust gas line the reducing agent composition of claim 1.