Assessment of a Gas Quality Survey for Interchangeability David Rue, William Liss Gas Technology Institute Algonquin Gas Pipeline Northeast Stakeholders.

Assessment of a Gas Quality Survey for Interchangeability

David Rue, William Liss

Gas Technology Institute

Algonquin Gas Pipeline

Northeast Stakeholders Group

June 15, 2006

Regional Natural Gas Composition Variations Exist

Average Natural Gas Composition -- Twenty Six US Cities

Source: Gas Technology Institute

Non-Methane Natural Gas Constituents

12

34

56

78

910

1112

1314

1516

1718

1920

2122

2324

2526

Survey City Number

0

5

10

15

20Non-Methane Constituents (Mole%)

Ethane Propane Butanes+ Inerts

Natural Gas and LNG

Adjust gases are typical U.S. natural gases at city gates (GRI, 1992)

8081828384858687888990919293949596979899

100101102103104105

1st a

djust

2nd a

djust

Trinid

ad

3rd a

djust

Trinid

ad

Alger

ia

Alger

ia

Indones

ia

Mal

aysi

a

Indones

ia

Qatar

Badak

Niger

ia

Qatar

Abu Dhab

i

Adgas

Brunei

Austra

lia

Mal

aysi

a

Libya

Oman

% C

om

po

sit

ion

1000

1010

1020

1030

1040

1050

1060

1070

1080

1090

1100

1110

1120

1130

1140

1150

1160

1170

[BT

U/s

cf]

N2

CX

C3

C2

C1

HHV

LNG Adjustment MethodsIn-tank Blending Mix low and high-Btu LNG. Requires

inventory of low-Btu LNG

Pipeline Blending

Best when large volumes of low-Btu gas are available (Gulf Coast)

Air Injection Up to 3.8% air. Capital cost and oxygen content concerns

Nitrogen injection

Up to 2% nitrogen. Capital cost. Used by Distrigas and Cove Point.

NGL stripping Capital cost. Need market for liquids

Streaming Cargo ‘streamed’ through terminal to less-sensitive user (e.g. power)

Approaches to Interchangeability Prediction – Focus on Appliances

• Single index (Wobbe, modified Wobbe, etc.)– Incapable of describing all possible situations

• Multiple indices (AGA, Weaver, etc.)– Specific to burner type– Do not account for all fuel gases or emissions– Most common U.S. approach

• Diagrams– Do not account for all fuel gases or emissions– Attempt to combine Wobbe index with composition

parameters – Many variations and not universally accepted– Often used in Europe

Wobbe Number• Generally accepted as the best SINGLE index to

determine interchangeability• For natural gas – alkanes – heat input through

an orifice (Btu/h) at constant pressure is– proportional to heating value and– inversely proportional to the square root of specific

gravity

• Wobbe Number does not fully address interchangeability because changes in flame characteristics are not addressed

W = HHV / (sp. gr.)0.5

Interchangeability is Defined As -

The ability to substitute one gaseous fuel for another in a combustion application without materially changing operational

safety or performance and without materially increasing air pollutant emissions

Source – NGC+ Working Group on Interchangeability White Paper presented to FERC, Feb. 2005

Possible Combustion Problems With High BTU Gas

Reported Problem From

Flame lifting Excess air

Backfiring Ow excess air or low velocity

High CO Incomplete combustion

High NOx Higher flame temperature

Yellow tippingFlame lengthening from incomplete combustion

Sooting Unburned hydrocarbon buildup

Interchangeability For AppliancesThe American Experience

• AGA and USBM indices set limits for appliance fuel interchangeability

•

•

• ANSI codes are not specific for interchangeability• Interchangeability studies have been made by GTI, IGT, A.D.

Little, SoCalGas, and others– No appliance failed AGA Index or ANSI limits with LNGs– CO is most sensitive measure of performance– Some appliances have high CO with ‘hot’ LNGs

• Indices developed for older appliances do not always predict behavior of new, high-efficiency appliances

AGA Yellow tipping

Flashback

Lifting

USBM Yellow tipping Air Supply

Flashback Heat release

Lifting Incomplete combustion

Effects of Fuel Changes: Appliances and Industrial Burners

• Different appliance burners show changes in performance

• No burner exhibited a failure case of flame lifting, excessive yellow tipping, or high CO emissions

• Important performance characteristics are different for industrial burners than for residential appliances

• Industrial burners are monitored more closely but operated at more demanding conditions

Source: Gas Technology Institute

Effects of Fuel Changes: Appliances and Industrial Burners

• Industrial burners can be categorized– Some burner types, like appliances, are relatively

unaffected by changing fuel

• Burners sensitive to changing fuel include:– Burners for which flame temperature changes strongly

impact the process– Burners in high temperature processes or where

emissions are tightly regulated– Burners operating close to stability limits

• Only sensitive burner types need to be evaluated for gas interchangeability

Industrial Burners – Interchangeability Concerns

• Unlike appliances, industrial burners are complex, highly engineered, and operate under precisely controlled conditions

• Changing fuel can affect industrial burners – Performance

• Flame length, temperature, flame shape, mixing patterns, etc.

– Safety• Stability, operating range, air/fuel ratio, etc.

– Meeting regulations• Emissions of NOx, CO, etc.

• Wobbe is still best index of interchangeability

What Needs to be Learned?

Application Concern Status Need

Appliances Millions of unregulated units

Studies made, results must be compared

Testing of old, maladjusted, and new units

Commercial/ Industrial Burners

Widest range of use, efficiency, emissions

Not yet addressed

Extensive testing

Engines and Boilers

Knock, efficiency, emissions, stable combustion

Mobile engines studied, others not yet addressed

Review mobile engine data and testing

Turbines/ Microturbines

Efficiency, emissions, turbine life

New FL study planned with full-scale turbines

Collect turbine maker data and testing

Non-combustion Uses

Added process cost, plant modification

Not yet addressed

Market analysis and data collection

Work Scope• Receipt of –

– Survey of northeast industrial gas customers by SIC (or NAICS) code, engines, turbines

– Current natural gas and expected LNG ranges

• Identification of industrial burners used by specific industrial customers – largest combustion uses

• Itemizing of engines and turbines by manufacturer, model, type, and quantity

• Ranking of burners, engines, and turbines into categories – considering gas composition ranges

• Explanations provided of interchangeability reasons for placement of combustion systems into categories

Ranking Criteria• Burners and processes not expected to have any

operational, performance, or emissions concerns over the full range of specified fuel gas compositions

• Burners and processes that may have some concerns over the specified fuel gas range and may eventually need to be looked at more closely. These include– those considered to be of some concern, but likely will handle

the charges in gas composition with no difficulties– those for which insufficient information is available and may

need to be studied before making a judgment

• Burners and processes with operations, performance, or emissions concerns over at least part of the range of gas compositions. Further study would be advised for these systems before introducing a new fuel gas such as LNG.

Deliverable – Final Report

• Summary overview of industrial burners, engines, and turbines identified in survey– Number and type listed where possible– Burner types summarized by SIC codes

• Analysis of burners, engines, and turbines– General comments on impacts of proposed gas

ranges on listed combustion systems– Ranked in three classes based on changing gas

• Little or no impact expected • Some impact expected or too little information available to

decide about impacts• Impacts expected and more detailed study of combustion

systems recommended

Cost and Schedule

• Cost– Project cost - $69,000– Includes initial and final trips to meet with sponsors

• Schedule– Work planned from June 15, 2006 through August 15,

2006– GTI will start work immediately with partial survey

results– Work completion is dependent on completed

Northeast Stakeholders Group surveys– Work can be slowed if all survey results are not

available

Classification of Industrial Burners

1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry

Classification Criteria

GTI Proprietary & Confidential

1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry


• Diffusion Mixed– Non-Staged– Air Staged– Fuel Staged

• Partial Pre-mixed– Non-Staged– Air Staged

• Pre-Mixed– Non-Staged

1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry

• Gas• Liquid• Solid• Dual


1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry


• Air• Oxygen• Oxygen Enriched Air• Preheated Air

1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry


• Forced Draft• Natural Draft• Inspirated• Aspirated

1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry


• Direct• Indirect

1. Mixing Type

2. Fuel Type

3. Oxidizer Type

4. Draft Type

5. Heating Type

6. Burner Geometry


• Round Nozzle• Rectangular Nozzle• Swirl

Burner Types

1. Radiant Burners

2. High Velocity Burners

3. Regenerative Burners

4. Natural Draft Burners

5. Boiler Burners

6. Linear Grid / In-Duct Burners

7. Oxygen Enhanced / Oxy-Fuel Burners

8. Flare Burners

Burner Types1. Radiant Burners




5. Boiler Burners



8. Flare Burners

• Radiant Wall• Thermal Radiation• Radiant Tube





5. Boiler Burners



8. Flare Burners

• Radiant Wall– Natural Draft– Forced Draft

• Pre-mixed• Non-Premixed

• Thermal Radiation• Radiant Tube

Burner Types

1. Radiant Burners




5. Boiler Burners



8. Flare Burners

• Radiant Wall• Thermal Radiation

– Porous Ceramic

– Ported Ceramic

– Fiber Metal

– Flame Impingement

– Catalytic

– Perforated Ceramic

– Porous Refractory

– Wire Mesh

• Radiant Tube





5. Boiler Burners



8. Flare Burners

• Radiant Wall• Thermal Radiation• Radiant Tube

– Non-Circulating– Recirculating– Forced Draft– Inspirating





5. Boiler Burners



8. Flare Burners

• Pre-mixed• Diffusion Mixed• Partially Pre-mixed• Air Staged





5. Boiler Burners



8. Flare Burners

• One Box• Two Box• Rotary / Heat

Wheel• Radiant Tube





5. Boiler Burners



8. Flare Burners

• Round Flame• Wall Fired Flat

Flame• Radiant Wall• Flat Flame





5. Boiler Burners



8. Flare Burners

• Low NOx• Ultra Low NOx• Conventional





5. Boiler Burners



8. Flare Burners

• Low NOx– External Flue Gas

Recirculation (EFGR)– Air Staged– Fuel Staged– Fuel Induced Recirculation

• Ultra Low NOx• Conventional





5. Boiler Burners



8. Flare Burners

• Low NOx• Ultra Low NOx

– Pre-mixed– Partially Premixed– Rapid Mix– Internal Flue Gas

Recirculation

• Conventional





5. Boiler Burners



8. Flare Burners

• Low NOx• Ultra Low NOx• Conventional

– Swirl– Register





5. Boiler Burners



8. Flare Burners

• Duct– Linear Grid– Grid

• Make-up Air





5. Boiler Burners



8. Flare Burners

• Air-Oxy Fuel– Concentric Pipe– Multiple Nozzle– Flat Flame– Staged

• Oxy-Fuel– Polishing– Forehearth





5. Boiler Burners



8. Flare Burners

• Single Point– Non Assisted

– Simple Steam Assisted

– Advanced Steam Assisted

– Low Pressure Air Assisted

• Multi-point• Enclosed





5. Boiler Burners



8. Flare Burners

• Single Point• Multi-point

– Non Assisted

– Simple Steam Assisted

– Advanced Steam Assisted

– Low Pressure Air Assisted

• Enclosed





5. Boiler Burners



8. Flare Burners

• Single Point• Multi-point• Enclosed

– Non Assisted– Simple Steam Assisted– Advanced Steam Assisted– Low Pressure Air Assisted

Burner Applications1. Radiant Burners




5. Boiler Burners



8. Flare Burners

• Thermal Radiation– Drying – Plastic

thermoforming– Paint curing

• Radiant Tube– Indirect heating

• Radiant Wall– Process Industry





5. Boiler Burners



8. Flare Burners

• Metals Industry• Ceramic/Glass

Industry





5. Boiler Burners



8. Flare Burners

• Zinc Distillation • Metals Industry • Glass Industry

Burner Applications

1. Radiant Burners




5. Boiler Burners



8. Flare Burners

• Chemical and Hydrocarbon Process Industries





5. Boiler Burners



8. Flare Burners

• Steam Generation• Water Heating• Space Heating





5. Boiler Burners



8. Flare Burners

• Space Heating• Turbine Exhaust• Uniform Spread

Heating





5. Boiler Burners



8. Flare Burners

• Metal Heating• Metal Melting• Glass Melting• Mineral Calcining





5. Boiler Burners



8. Flare Burners • Petrochemical Industries

Assessment of a Gas Quality Survey for Interchangeability David Rue, William Liss Gas Technology Institute Algonquin Gas Pipeline Northeast Stakeholders.

Documents

gas technology institute

incomplete combustion

power slide

europe slide

highbtu lng

natural gases

wobbe index

fuel gases