# US 10,309,278 B2 · Method for desulfurization of selective catalytic reduction devices

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- Number: US 10,309,278 B2
- Document ID: US10309278B2
- Status: Granted
- Kind: B2
- Application number: 15/723,747
- Filed: 2017-10-03
- Published: 2019-04-04
- Granted: 2019-06-04
- Earliest claimed: 2017-10-03
- Assignees: GM Global Technology Operations LLC
- Applicants: GM Global Technology Operations LLC
- Inventors: Rahul Mital; Gongshin Qi; Anil Yadav
- Web page: https://patentgrep.com/patent/US10309278B2

## CPC

- F01N 3/0885: {Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps}
- B01D 53/8609: {Sulfur oxides}
- B01D 53/94: by catalytic processes
- B01D 53/9431: {Processes characterised by a specific device}
- B01D 53/9495: {Controlling the catalytic process}
- F01N 3/105: {General auxiliary catalysts, e.g. upstream or downstream of the main catalyst}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- B01D 2251/2062: Ammonia
- B01D 2255/2027: Sodium
- B01D 2255/2042: Barium
- B01D 2255/20707: Titanium
- B01D 2255/20723: Vanadium
- B01D 2255/20738: Iron
- B01D 2255/20746: Cobalt
- B01D 2255/20761: Copper
- B01D 2255/20769: Molybdenum
- B01D 2255/20776: Tungsten
- B01D 2255/2092: Aluminium
- B01D 2255/40: Mixed oxides
- B01D 2255/50: Zeolites
- F01N 2550/02: Catalytic activity of catalytic converters
- F01N 2560/026: for measuring or detecting NOx
- F01N 2560/14: having more than one sensor of one kind
- F01N 2610/02: the substance being ammonia or urea
- F01N 2900/1402: Exhaust gas composition
- F01N 2900/1602: Temperature of exhaust gas apparatus
- F01N 2900/1614: NOx amount trapped in catalyst
- 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

Described herein is a desulfurization method for desulfurizing a SCR device treating an exhaust gas. The desulfurization method includes injecting a reductant into the exhaust gas upstream from or into the SCR device and increasing a temperature of the exhaust gas.

## Claims

### Claim 1

An emissions control system for treating exhaust gas in a motor vehicle including an internal combustion engine, the emissions control system comprising:
a selective catalytic reduction (SCR) device;
a controller operably connected to the SCR device and configured to perform a desulfurization method to desulfurize the SCR device by:
injecting a reductant into the exhaust gas upstream from or into the SCR device; and
increasing a temperature of the exhaust gas;
a downstream NOx sensor operably connected to and in fluid communication with the exhaust gas, the downstream NOx sensor disposed downstream of the SCR device and operably connected to the controller; and
an upstream NOx sensor operably connected to and in fluid communication with the exhaust gas, the upstream NOx sensor disposed upstream of the SCR device and operably connected to the controller,
wherein the downstream NOx sensor is configured to measure a downstream NOx value of the exhaust gas from the downstream NOx sensor, and
wherein the upstream NOx sensor is configured to measure a upstream NOx value of the exhaust gas from the upstream NOx sensor, and
wherein the desulfurization method further comprises:
measuring a downstream NOx value from the downstream NOx sensor;
measuring an upstream NOx value from the upstream NOx sensor; and
determining a NOx conversion efficiency using the downstream NOx value and the upstream NOx value,
wherein, if the NOx conversion efficiency is equal to or less than a NOx conversion efficiency lower limit, the injecting of the reductant and the increasing of the temperature of the exhaust is initiated.

### Claim 2 (depends on 1)

The emissions control system of claim 1, wherein the controller is programmed to inject the reductant and increase the temperature of the exhaust gas for a selected duration.

### Claim 3 (depends on 2)

The emissions control system of claim 2, further comprising a temperature sensor operably connected to and in fluid communication with the exhaust gas, the temperature sensor operably connected to the controller, wherein desulfurization method further comprises:
measuring the temperature of the exhaust gas; and
after increasing the temperature of the exhaust gas, maintaining the temperature of the exhaust gas at a predetermined temperature until the end of the selected duration.

### Claim 4 (depends on 1)

The emissions control system of claim 1, wherein the temperature of the exhaust gas is increased to 300° C. to 500° C.

### Claim 5 (depends on 1)

The emissions control system of claim 1, further comprising:
a downstream NOx sensor operably connected to and in fluid communication with the exhaust gas, the downstream NOx sensor disposed downstream of the SCR device and operably connected to the controller,
wherein the downstream NOx sensor is configured to measure a downstream NOx value of the exhaust gas from the downstream NOx sensor, and
wherein the desulfurization method further comprises:
measuring the downstream NOx value from the downstream NOx sensor,
wherein, if the downstream NOx value is equal to or greater than a NOx threshold value, the injecting of the reductant and the increasing of the temperature of the exhaust gas is initiated.

### Claim 6 (depends on 5)

The emissions control system of claim 5, wherein the injecting of the reductant and the increasing of the temperature of the exhaust gas continues until at least one of:
a selected duration ends; and
a downstream NOx value equal to or less than a selected NOx value is measured.

### Claim 7 (depends on 1)

The emissions control system of claim 1, wherein the injecting of the reductant and the increasing of the temperature of the exhaust gas continues until at least one of:
a selected duration ends; and
a NOx conversion efficiency equal to or greater than a selected NOx conversion efficiency is determined.

### Claim 8 (depends on 1)

A vehicle comprising the emissions control system of claim 1.

### Claim 9

A desulfurization method for desulfurizing a selective catalytic reduction (SCR) device treating an exhaust gas, comprising:
injecting a reductant into the exhaust gas upstream from or into the SCR device;
increasing a temperature of the exhaust gas;
measuring a downstream NOx value from a downstream NOx sensor;
measuring an upstream NOx value from an upstream NOx sensor; and
determining a NOx conversion efficiency using the downstream NOx value and the upstream NOx value,
wherein, if the NOx conversion efficiency is equal to or less than a NOx conversion efficiency lower limit, the injecting of the reductant and the increasing of the temperature of the exhaust is initiated.

### Claim 10 (depends on 9)

The desulfurization method of claim 9, wherein the injecting of the reductant and the increasing of the temperature continues for a selected duration to desulfurize the SCR device, wherein the selected duration is equal to or greater than 10 minutes.

### Claim 11 (depends on 10)

The desulfurization method of claim 10, further comprising:
measuring the temperature of the exhaust gas; and
after increasing the temperature of the exhaust gas, maintaining the temperature of the exhaust gas at a desulfurization temperature until the end of the selected duration.

### Claim 12 (depends on 9)

The desulfurization method of claim 9, further comprising:
measuring a downstream NOx value of the exhaust gas,
wherein, if the downstream NOx value is equal to or greater than a NOx threshold value, the injecting of the reductant and the increasing of the temperature of the exhaust gas is initiated.

### Claim 13 (depends on 12)

The desulfurization method of claim 12, wherein the injecting of the reductant and the increasing of the temperature of the exhaust gas continues until at least one of:
a selected duration ends; and
a downstream NOx value equal to or less than a selected NOx limit value is measured.

### Claim 14 (depends on 12)

The desulfurization method of claim 12, wherein, during the injecting of the reductant, a molar ratio of the reductant to the downstream NOx value is 0.5:1 to 4:1.

### Claim 15 (depends on 9)

The desulfurization method of claim 9, wherein the injecting of the reductant and the increasing of the temperature of the exhaust gas continues until at least one of:
a selected duration ends; and
a NOx conversion efficiency equal to or greater than a selected NOx conversion efficiency is determined.

### Claim 16 (depends on 9)

The desulfurization method of claim 9, wherein the injecting of the reductant is in an amount equal to or greater than 200 ppm by weight, based on the total weight of the exhaust gas.

### Claim 17 (depends on 9)

A method for controlling emissions in exhaust gas from a motor vehicle including an internal combustion engine, comprising:
treating the exhaust gas in a selective catalytic reduction (SCR) device; and
desulfurizing the SCR device using the desulfurization method of claim 9.