Regulatory Impacts of Biogas-fired Internal Combustion Engines

Kit Liang, PE, Malcolm PirnieKit Liang, PE, Malcolm Pirnie

Air, Water & Energy: Sustainability for Wastewater Air, Water & Energy: Sustainability for Wastewater Treatment PlantsTreatment PlantsCalifornia Water Environment Association California Water Environment Association

Santa Ana River Basin Section Santa Ana River Basin Section

June 11, 2009June 11, 2009

AgendaAgenda

• Backgroundg• Biogas use for IC engines• Engine type/ emissionsEngine type/ emissions

• Regulations• SCAQMD Rule 1110 2 1401 1402• SCAQMD - Rule 1110.2, 1401, 1402 • USEPA – NSPS, MACT

Case Study Orange County Pilot Testing• Case Study – Orange County Pilot Testing

What is Biogas ?What is Biogas ?

P d d f bi d itiProduced from anaerobic decomposition of organic materials

Primary sources

• Landfill • Wastewater treatment - Digester gas

Renewable fuel

Biogas CompositionBiogas Composition

Methane (CH ) (45 65 %)• Methane (CH4) (45 – 65 %)• Carbon Dioxide (CO2) ( 35 – 55 % )

C t i t• Contaminants: • VOCs• Sulfur• Siloxanes• Ammonia• Miscellaneous - PM, moisture

Where is biogas used at WWTP?Where is biogas used at WWTP?

• Combustion• IC Engines• BoilersBoilers• Turbines• Flares• Flares

• Clean and compress to liquefied or compressed natural gasnatural gas

• Release to atmosphere

Reciprocating Internal Combustion E i (RICE)Engines (RICE)

Cover a broad range of output horsepower and speeds

Widespread applications

• Good fuel economy

• Durability

• Reliability

• Compactness

• Reasonable first cost

Classification of RICEClassification of RICE

Engines are classified according to their fuel typeEngines are classified according to their fuel type and ignition method

• Gas Engines - use gaseous fuel and are spark-ignited (SI)

• Diesel Engines – compression ignition (CI) engines operate on liquid fuel oiloperate on liquid fuel oil

• Dual-Fuel Engines – two modes of operation: one is operated as a diesel engine; in the other mode a “pilot “ injection of liquid diesel fuel ignites as in a diesel engine and subsequently ignites the main charge of fuel gas and air mixture – EPA classified as spark-ignited

Emissions from Biogas CombustionEmissions from Biogas Combustion

• Criteria pollutantsCriteria pollutants• NOx, CO, VOCs, SOx

• Hazardous air pollutants (HAPs)• Hazardous air pollutants (HAPs) • Formaldehyde

A t ld h d• Acetaldehyde• Acrolein• Methanol

• Biogas-fired engines are major contributors to facility wide emissions from WWTPfacility-wide emissions from WWTP

Type of RegulationsType of Regulations

S t i• Source categories• Internal Combustion Engines (ICE)

• Facility-wide emissions• Existing versus new/modified sources• Pollutant type

• Criteria (NOx, CO, SOx, VOCs)• Air toxics or HAPs (e.g., formaldehyde)

General Regulation for ICEGeneral Regulation for ICE

• Local – South Coast Air Quality Management Q y gDistrict (SCAQMD)

• Federal • Title V – Operating Permit (facility-wide) • Source Categories g

• New Source Performance Standards (NSPS)

• National Emission Standards for Hazardous Air PollutantsNational Emission Standards for Hazardous Air Pollutants (NESHAPS)

• Maximum Achievable Control Technology (MACT)

SCAQMD RegulationsSCAQMD Regulations

Rule 1110 2• Rule 1110.2 • Gaseous and liquid-fuel engines• Units > 50 BHP

• Rules 1300 to 1316C it i P ll t t (CO NO PM10 SO VOC )• Criteria Pollutants (CO, NOx, PM10, SOx, VOCs)

• Rule 1401 and 1402 T i Ai C t i t ( f ld h d )• Toxic Air Contaminants (e.g., formaldehyde)

Rule 1110.2 – Biogas fired IC EnginesRule 1110.2 Biogas fired IC Engines

• Applies to IC Engines > 50 BHP• Applies to IC Engines > 50 BHP• Biogas-fired engine – requirements

• Engines use > 90 % biogas • Unless SCAQMD provides variance

• Existing NOx limits: • Natural Gas - 36 ppm• Biogas - 36 ppm or calculated based on efficiency

correction factor (ECF)

SCAQMD Rule 1110.2

Regulation applies to existingRegulation applies to existing IC enginesSchedule

Concentration(ppmvd)

• Final amendment issued Feb 2008

• Technology Evaluation for it ti bi b

Existing Future

NOx 36 to ~ 45 11units operating on biogas by July 2010

• Natural gas-fired engines meets limits by July 2011

CO 2000 250

VOC 100 30 meets limits by July 2011

• Biogas-fired engines meet limits by July 2012

VOC 100 30

* Concentration in units of parts per million at volume dry @ 15% O2)

Source of Siloxanes at WWTP

Common isomers:Common isomers:D4 - OctamethylcyclotetrasiloxaneD5 - Decamethylcyclopentasiloxane

Siloxanes are use in personal care products

Why are Siloxanes a Problem?Why are Siloxanes a Problem?

Silica Formation

D4 and D5 -exist in the F Sili

Silica Formation

exist in the gas phase of

biogas Oxidation

Forms Silica:a particulate

Fouls fuel systems,combustion chambersand post-combustion controls.

SCAQMD Regulations – All SourcesSCAQMD Regulations All Sources

• Rules 1300 to 1316• Criteria Pollutants (CO, NOx, PM10, SO2, VOCs) • Best Available Control Technology (BACT)

• Rule 1401 and 1402 • Toxic Air Contaminants (formaldehyde)• Toxic Air Contaminants (formaldehyde)• Rule 1401 – new/modified source • Rule 1402 – existing facility-wideRule 1402 existing facility wide

• Biogas engines included

Federal Regulations – Source CategoriesFederal Regulations Source Categories

40 CFR 60 N S P f St d d (NSPS)• 40 CFR 60 - New Source Performance Standard (NSPS)• Emissions limits for new sources (NOx, CO, VOCs)

• 40 CFR 63 - Maximum Achievable Control Technology• 40 CFR 63 - Maximum Achievable Control Technology (MACT) – Air Toxics • List of 187 hazardous air pollutants (HAPs)• Major or non major (area) source • 10 tpy of individual and 25 tpy of total HAPS

f• Emissions limits for existing and new engines

• Emissions limits • Engine type size and usage• Engine type, size and usage

40 CFR 60 - New Source Performance St d d (NSPS)Standards (NSPS)

• Subpart JJJJ – SI Engines (1/18/08)• Gaseous fuels – biogas and natural gas • Emissions limits for NOx, CO, VOCs• Dual fuel – diesel fuel, biogas, natural gas, g , g

• Subpart IIII – CI Engines (7/11/06)• Diesel fuelDiesel fuel

Subpart JJJJ Requirements for Biogas-fi d E ifired Engines

• New and modified units after 6/12/06• New and modified units after 6/12/06• Emissions limits are based on engine type

and fuel typeand fuel type• Emission limits:

• NOx 150 to 220 ppmvd*• NOx – 150 to 220 ppmvd• CO – 610 ppmvd*

VOC 80 d*• VOC – 80 ppmvd*

* ppmvd – parts per milliton by volume dry @ 15% O2

40 CFR 63 – Subpart ZZZZ (RICE MACT)40 CFR 63 – Subpart ZZZZ (RICE MACT)

Existing Rule (7/15/04)• Existing Rule – (7/15/04)• > 500 HP engines at major source

P d A d t (3/5/09)• Proposed Amendments (3/5/09)• < 500 HP at major source• All engines at non-major (area) sources• Additional provisions:

• Emergency engines

• Startup, shutdown, and maintenance conditions

40 CFR 63 – Subpart ZZZZ (RICE MACT) E i ti R l– Existing Rule

• Existing rule (6/15/04)• Existing rule – (6/15/04)• > 500 HP at major source

Formaldehyde primary air toxic• Formaldehyde primary air toxic • Emission limit based on engine type:

• CO : Reductions range from 58% to 93% ; or • Formaldehyde emission limit from 0.35 to 12 ppmvd

• No emission limits or controls required for biogas-fired engines

40 CFR 63 – Subpart ZZZZ(RICE MACT) P d A d t(RICE MACT) – Proposed Amendments

• Proposed amendments to rule (3/5/009)• Proposed amendments to rule (3/5/009)• IC engines < 500 HP at major source• All engines at non major (area) sources• All engines at non-major (area) sources • Additional provisions for:

E i• Emergency engines• Startup, shutdown, and maintenance

• Use carbon monoxide as surrogate for formaldehyde

40 CFR 63 – Subpart ZZZZ – Biogas EnginesEngines

No limit for engines >500 hp at major source• No limit for engines >500 hp at major source (final Rule)

• Proposed Amendment (3/5/09)• Proposed Amendment (3/5/09)• CO Limit : 177 ppmvd

F 50 t 500 HP t j• From 50 to 500 HP at major sources

• > 500 hp at no- major sources

Orange County Sanitation DistrictOrange County Sanitation District

• Two Wastewater Treatment Plants• Plant 1 – Fountain Valley ~ 90 MGD

• Plant 2 – Huntington Beach ~ 160 MGD

• Central Generation SystemCentral Generation System • Plant 1 – 3 ICE (2,500 KW each)

• Plant 2 5 ICE (3 000 KW each)• Plant 2 – 5 ICE (3,000 KW each)

AB2588 and Rule 1402 Control f T i Ai C t i tof Toxic Air Contaminants

• Existing facilitiesExisting facilities

• Specified risk limits

• Facility-wide emissions

• Public notification and inventory requirements

Pilot Testing: Reduce Formaldehyde and COPilot Testing: Reduce Formaldehyde and CO

C t l ti idi f• Catalytic oxidizer performance• Emission Reduction: formaldehyde, CO

N d t f f• No vendor guarantees for performance

• Impact of digester gas contaminants on catalytic oxidizerscatalytic oxidizers

• Digester gas cleaning system performance • Feasibility of operating catalytic oxidizer

with digester gas cleaning

Catalytic Oxidizer and Digester Gas Cleaning SystemCleaning System

Digester gas cleaning system

Catalytic oxidizer

cleaning system

Catalytic Oxidizer: Emissions TestingCatalytic Oxidizer: Emissions Testing

• Portable Analyzer – Weekly Testingy y g• Real-time • CO• NOx

• EPA Method 323 – Monthly Testing • Wet chemistry method• Wet chemistry method • Formaldehyde

• Fourier Transform Infared (FTIR) ( )• Real Time • NOx, CO, formaldehyde • Speciated VOCs and amines

Method 323: Sampling and Set-upp

Sampling Port LocationsSampling Port Locations

Cat Oxd InletCat Oxd St k O tl tCat Oxd InletOutlet Stack Outlet

Pilot Testing Summary – Catalytic Oxidizer ith Di t G Cl i S twith Digester Gas Cleaning System

• Emissions• CO: 90 - 95 % reduction• NOx : 15 -20 % increaseNOx : 15 20 % increase

• Limitation of sampling measurements

• Catalyst Rx with other nitrogen bound compounds• Catalyst Rx with other nitrogen-bound compounds

• Formaldehyde: 55 to 75% reduction

Pilot Testing Summary – Catalytic Oxidizer ith Di t G Cl i S twith Digester Gas Cleaning System

E i f• Engine performance • No issues with temperature increase or pressure

dropsdrops • Reduced engine maintenance

C t l ti idi tl till ti ith• Catalytic oxidizer currently still operating with no catalyst replacement (> 1 year)

What’s Next for OCSD?What s Next for OCSD?

• Future SCAQMD Rule 1110.2 requirements• Technology evaluation for meeting new limits• Second pilot testing program to control NOx,

CO and air toxics emissions • Information to SCAQMD by May 2010

SummarySummary

• SCAQMD Rules are more restrictive than• SCAQMD Rules are more restrictive than existing NSPS and MACT regulations

• Proposed MACT regulations affects IC engines at non-major facilities.

• Facilities needs to be plan for the future requirementsrequirements.