scr_def ed%2e presentation final version

7/27/2019 Scr_def Ed%2e Presentation Final Version

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Selective Catalytic Reduction (SCR)

Diesel Exhaust Fluid (DEF)

CAT, CATERPILLAR, their respective logos,

"Caterpillar Yellow," the "Power Edge" trade dress as

well as corporate and product identity used herein, are

trademarks of Caterpillar and may not be used withoutpermission.


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GENERATIONS AHEAD 2

Overview

Selective Catalytic Reduction (SCR) Definition

SCR System Components


Pump Electronics Tank Unit (PETU) DEF Injector

Mixing Tube

SCR Catalyst

Ammonia Oxidation Catalyst (AMOX) Diesel Exhaust Fluid (DEF)

Difference between Urea and DEF

Importance

Purchasing Options Packaging Options

Storage Considerations

Handling Information

Summary


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GENERATIONS AHEAD 3

What is Selective Catalytic Reduction (SCR)?

Selective Catalytic Reduction (SCR) is the process by which oxides of nitrogen (NOx)

contained in diesel exhaust are reduced to nitrogen (N2) and water (H2O)

Selective Catalytic Reduction

Selective: targets NOx in diesel exhaust

Catalytic: requires a catalyst

Reduction: NOx is reduced to nitrogen (N2)

Requires Diesel Exhaust Fluid (DEF) a urea based solution

The Cat SCR System functions transparently to the operator

SCR reduces NOx emissions up to 93%


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GENERATIONS AHEAD 4

Why is Selective Catalytic Reduction (SCR) being used with Cat Engines?(130 560 kW)

SCR is an effective and efficient way to further reduce NOx emission levels from Tier 4 Interim/ EU Stage IIIB emission standards to Tier 4 Final / EU Stage IV emission standards

Significant reduction in NOx

achieved with the addit ion of

SCR System


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GENERATIONS AHEAD 5

Brief Selective Catalyt ic Reduction (SCR) History

SCR is already being implemented in a variety of applications

Current Applications

Gas Turbines

Stationary Installations

Electric Power

On-Highway Trucks (European models beginning in 2006, U.S. models beginning in 2010)

European Combined Heat & Power (CHP) Installations

To conform with Tier 4 Final / EU Stage IV emission standards, Cat Engines in the

130-560 kW power range will add a Selective Catalytic Reduction (SCR) System to

the Clean Emissions Module (CEM), a component utilized to meet Tier 4 Interim / EU

Stage IIIB emission standards


6/30GENERATIONS AHEAD 6

Cat Tier 4 Final / EU Stage IV Aftertreatment Strategy

Tier 4 Final / EU Stage IV = Tier 4 Interim / EU Stage IIIB + SCR System

No chassis

redesign required


7/30GENERATIONS AHEAD 7

Selective Catalytic Reduction (SCR) System Components


Pump Electronics Tank Unit (PETU)

DEF Injector

Mixing Tube SCR Catalyst

Ammonia Oxidation Catalyst (AMOX)


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GENERATIONS AHEAD 8


DEF is a urea based solution

Composition

67.5% de-ionized water

32.5% urea

Urea

Under heat, decomposes to ammonia(NH3) and carbon dioxide (CO2)

Ammonia (NH3) reacts with NOx in the

presence of a catalyst

DEF is required for the SelectiveCatalyt ic Reduction (SCR) System

to function


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GENERATIONS AHEAD 9

Pump Electronics Tank Unit (PETU)

Components

Tank for onboard storage of DEF

Pump to supply DEF to the SCR

System Heated lines to prevent freezing

Coolant Diverter Valve to supply

coolant to the DEF Injector

Separate Electronic Control Module(ECM) controls DEF dosing

By regulation, the DEF tank is

designed with a minimum of a 1:1 fillratio with the fuel tank

No more than 1 tank of DEF is consumed with 1 tank of fuel


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GENERATIONS AHEAD 10

PETU Components

Fill Adapter and Cap

DEF-out to injector

Heated DEF lines

Coolant Diverter

Valve

Tank

Power Relays

DEF Controller

Voltage Line Protection

Module


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PETU (Tank Removed)

DEF Pump Assembly

DEF Pickup

DEF Level Sensor

DEF Temperature

Sensor

DEF Tank Heater

DEF-out to injector


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PETU Pump Assembly

DEF Filter Assembly

(5000 hr service interval)

Pump Assembly

DEF Filter Kit

(5000 hr service interval)


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DEF

Coolant

SupplyCoolant

Return

Electrical

Connector

DEF Injector

DEF is supplied to the SCR System in the Mixing Tube via the DEF Injector(regulated by the Pump Electronics Tank Unit)

An internal coolant supply keeps the injector tip cool


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Mixing Tube

DEF is injected into the exhaust

stream in the Mixing Tube

Heat from the exhaust evaporates the

de-ionized water from the DEF,instantaneously decomposing the

urea, releasing ammonia (NH3) and

carbon dioxide (CO2)

The ammonia (NH3) uniformly mixes

with the NOx contained in the exhaustin the Mixing Tube

Mixing Tube

DEF + Heat Ammonia + Carbon Dioxide


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Selective Catalytic Reduction (SCR) Catalyst

The ammonia (NH3) and NOx mixture

in the exhaust stream enters the SCR

Catalyst from the Mixing Tube

The mixture passes over a Copper

Zeolite Catalyst

The SCR Catalyst causes a chemicalreaction between the ammonia (NH3)

and NOx

The final products are nitrogen (N2)

gas and water vapor (H2O) Up to 93% of NOx emissions

converted

Mixture enters the SCR

Catalyst here


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Ammonia Oxidation Catalyst (AMOX)

To prevent excess ammonia from

being emitted (ammonia slip), the SCR

System uses an AMOX to convert any

unused ammonia from the DEF tonitrogen (N2) and water (H2O)

A small amount of excess DEF is

injected into the SCR System to

ensure NOx conversion; the AMOXoxidizes any excess ammonia (NH3)

from the DEF that did not react with

the NOx

Final component in the Tier 4 Final /

Stage IV Aftertreatment system

Exhaust stream passes

through AMOX


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Selective Catalytic Reduction (SCR) / Diesel Exhaust Fluid (DEF)

Operator Interactions

Function of the SCR System is transparent to the operator

The only action required of the operator is to ensure the DEF tank is refilled

every time the fuel tank is refilled

PETU Filter Assembly / Filter Kit requires replacement every 5000 hours

If the Aftertreatment System is tampered with or the DEF level / quality is

insufficient, the engine will de-rate and eventually shut down if corrective

action is not taken


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Difference between Urea and DEF

Importance

Purchasing Options

Packaging Options

Storage Considerations

Handling Information


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What is the difference between Urea and Diesel Exhaust Fluid (DEF)?

Urea is a white, nitrogen containing compound that is solid at room

temperature

When heated, releases ammonia (NH3)

Often used as an agricultural fertilizer

Diesel Exhaust Fluid (DEF) is chemical grade urea in solution form which

is liquid at room temperature Composed of 32.5% urea and 67.5% de-ionized water


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Why do I need to use Diesel Exhaust Fluid (DEF)?

Urea contained in DEF decomposes

under elevated temperature into

ammonia (NH3) and carbon dioxide

(CO2) --- See Step 1

Ammonia (NH3) is the reductant which

reduces NOx contained in diesel

exhaust into nitrogen (N2) and water

(H2O) in the presence of the SCRCatalyst --- See Step 2

Without DEF, the SCR System will not

function --- Step 1 & 2 could not occur!

Urea is contained in

Diesel Exhaust Fluid


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Where can I purchase Diesel Exhaust Fluid (DEF)?

DEF can be purchased at a variety of locations:

Cat dealers

Retail locations such as on-highway truck fueling stations and automotive partsstores

Bulk delivery from DEF producers or fuel distributors

Any commercial DEF that meets the ISO 22241 specification is allowed for use in CatSCR equipped engines

For more information regarding availability of DEF, visit:

U.S. Europe

http://www.discoverdef.com http://www.findadblue.com
http://www.discoverdef.com/http://www.findadblue.com/http://www.findadblue.com/http://www.discoverdef.com/


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Can Agricultural Grade Urea be used instead of Diesel Exhaust Fluid (DEF)?

Urea which is used primarily as a fertilizer in the agriculture industry contains

numerous organic and inorganic contaminants. These contaminants must be tightly

controlled for agricultural grade urea to be used in place of Diesel Exhaust Fluid

(DEF). Because of the high risk of contaminants which could damage the SCRSystem, Caterpillardoes not allow the use of agricultural grade urea in Cat SCR

Systems.

Granular Agricultural Grade Urea


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What quantities of Diesel Exhaust Fluid (DEF) are available for

purchase?

Cat dealer packaging options include:

2.5 gallon bottles for single use

applications

264 gallon tote for multiple useapplications

DEF quantities are available in various

commercial categories including:

Single use: 1 gallon, 3 gallon, and 5

gallon containers

Semi-bulk: 100-250 gallon bins or

plastic totes

Small bulk: 250-500 gallon tanks

264 gallon tote

2.5 gallon bottle


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Storing Diesel Exhaust Fluid (DEF)

Inversely

Related

-DEF has a shelf li fe

-Increases in temperature increases the

rate of degradation

-DEF is corrosive to some metals


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Shelf Li fe

Exposure to

Sunlight

Storage

Temperature

How is Diesel Exhaust Fluid (DEF) Shelf Life affected by temperature?

Diesel Exhaust Fluid (DEF) is

inherently biodegradable

Increased storage temperature

decreases shelf life

Increased exposure to sunlight

decreases shelf life

DEF has a freezing point of 12F

The rate of decay significantly

accelerates when stored in

temperatures above 90F

Optimal temperature for storage is

15F - 77F


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Acceptable Containment Materials

DEF can be stored in the following materials:

304, 304L, 316L series Stainless Steel

400, 409, 439 series Stainless Steel

Highly alloyed austenitic Cr-Ni and Cr-Ni-Mo steels

Titanium

Polyethylene,

Polypropylene

Polyisobutylene

Perfluoroalkoxyl alkane (PFA)

Polyfluroethylene (PFE)

Polyvinylidenefluoride (PVDF)

Polytetrafluroethylene (PTFE) free of additives


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Unacceptable Containment Materials

DEF cannot be stored in the following materials:

Unalloyed steel

Galvanized steel

Aluminum / Aluminum alloys

Magnesium / Aluminum alloys

Copper

Brass Metals and plastics coated with nickel

Nonferrous metals and alloys (copper, copper alloys, zinc, and lead)


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Diesel Exhaust Fluid (DEF) Handling Information

Corrosive to steels and some metals

Spills must be cleaned up immediately

to avoid damage

Avoid contact with skin

Physical Properties

Colorless

Slight pungent ammonia odor

Chemical Properties

Highly reactive with oxidizers such as

bleach

For Safety Information, refer to the

Material Safety Data Sheet (MSDS)

DEF Corrosion on steel


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Diesel Exhaust Fluid (DEF) Disposal

As per the Material Safety Data Sheet (MSDS) for the ChemTool Brand

DEF available at Cat dealers:

The product, if disposed of AS SUPPLIED, is NOT specifically listed as an EPARCRA hazardous waste nor does it have the characteristics of an unlisted RCRA

hazardous waste as defined in 40 CFR 261. Use and/or alterations to the product

such as mixing with other materials may significantly change the characteristics

of the material and alter the RCRA classification and proper disposal method.

Under RCRA it is the responsibility of the user of the product to determine at the

time of disposal, whether the product meets RCRA criteria for a hazardous

waste.


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Key Points

1. Selective Catalyst Reduction (SCR) is transparent to the operator

2. The only action required of the operator is to ensure the DEF tank is refilled

at the same time as the fuel tank

3. DEF is required for the SCR system to function

4. Engine de-rate and eventual shutdown will occur in the event of: insufficientor poor quality DEF supply, as well as tampering with, disabling or removingany of the SCR System Components

5. DEF has a shelf life and should be stored between 15F 77F

6. DEF is corrosive and must be stored in a compatible containment material

scr_def ed%2e presentation final version

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