Susnata SamantaAugust 2016

Activated Carbon in Biomethane Production

Pedro Paixão

August 24th 2017

RCGI/GBIO/IEE

2

Agenda

Activated Carbon, Adsorption Process, Generalities

Activated Carbon for Biogas Purification

Activated Carbon Performance Data

23 AUGUST 2017 / PRESENTATION TITLE / CONFIDENTIAL / NOT FOR REDISTRIBUTION 3

Cabot-Norit Activated Carbon,Adsorption Process& Generalities

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Global Asset Base to Serve Customers

• 43 manufacturing sites in 21 countries, all with local management teams• 23 sales locations in 17 countries

manufacturing sitessales locationsaffiliatesregional headquarters

35%

30%

35%

AsiaAmericas

EMEA

Revenues

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Activated Carbon and Adsorption

Micropores < 1 nmMesopores 1-25 nmMacropores > 25 nm

Van der Waals forces allow the “capture” of impurities at the activated

carbon pores’ surface

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Raw Materials

Anthracite Coal

Bituminous Coal

Sub-Bituminous Coal

Lignite Coal

Coconut Shell

Peat

Wood

Olive Stones

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Production: Activation Processes

Process Goal Produce materials with extremely high internal porosity

and surface area, thus optimized adsorption efficiency and capacity, maintaining a consistent physical structure.

Specific finshing processes to enhance certain activated carbon characteristics, depending on the final application (e.g. washing, impregnation, pH adjustment, milling,...).

Cabot has the best manufacturing technology in place for the production of activated carbon, as well as access to a wide range of raw materials

Types of Activation Chemical Activation

Steam Activation

23 AUGUST 2017 / PRESENTATION TITLE / CONFIDENTIAL / NOT FOR REDISTRIBUTION 8

Activated Carbon for Biogas Purification

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Biogas: Activated Carbon Application Data

Source Biogas

Application

Agriculture

Waste

(animal or

vegetal)

Landfills

Engine or Microturbine

Fuel Cell

Gas Grid

WWTP’s

Biogas is a mixture of methane, CO2, moisture and traces of other contaminants. Biogas is widely available, renewable and

a sustainable energy source with an undisturbed supply of power. Biogas can be produced of a wide variety of available

organic materials like agriculture waste, crop residues, animal manure, sewage sludge and municipal organic waste. Biogas

is produced to generate electricity, heat or it could be upgraded to pipeline quality and connected to the national gas grid.

Electricity Production

Challenge Comment AC potential

Siloxanes Present

H2SPresent; Oxygen + moisture required, H2S concentration ideal max 200ppm, competitive technologies

Market Well documented

Siloxanes Present

H2SPresent; Oxygen + moisture required H2S concentration ideal max 200ppm,Competitive technologies

Market Well documented

Siloxanes Not present

H2SPresent; H2S concentration too high, competitive technologies

Market Fragmented, small volumes

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Energy Production: Engines, Microturbines

Removal of Siloxanes and/or H2S

Biogas Upgrade to Biomethane for Gas Grid or Fuel Cell

Removal of Siloxanes and/or H2S and/or VOC’s

Siloxanes removal to avoid fouling, which negatively impacts equipment life-time andoperation downtime. Siloxanes are literally the sand in the equipment!

Hydrogen Sulfide (H2S) removal to avoid heavy corrosion problems in the biogasprocessing equipment. H2S is a dangerous acidic gas, harmful to the environment.

Main Activated Carbon Applications

PSA / TSA (Pressure / Temperature Swing Adsorption) both technologies may workwith a carbon bed, or may use an activated carbon polishing filter (mainly for siloxanesand/or VOC’s, and perhaps some H2S traces if necessary).

Scrubbers are used to separate CO2, H2S and other contaminants from biogas, and canbe followed by activated carbon for final polishing (mainly siloxanes / VOC’s removal).

Membranes for CO2 removal, normally downstream an activated carbon filter that hasto effectively remove Siloxanes and VOC’s.

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Biogas Purification Process

Raw Biogas:

~ 60% Methane

~ 38 % CO2

~ 0-2% Oxygen

~ 1-500 ppm H2S

~ 1-10 ppm Siloxanes

~ 1-500 ppm VOCs

~ 5-20% Humidity

H2S Removal

GAC vessel

Chemical Rx. on AC surface, presence of oxygen & moisture

Physical Ads. from dry gas on AC surface

GAC vessel

Siloxane RemovalDrying to remove

moisture

Raw Biogas:

~ 60% Methane

~ 38 % CO2

~ 0-2% Oxygen

~ 1-5,000 ppm H2S

~ 1-10 ppm Siloxanes

~ 1-500 ppm VOCs

~ 90-100% Humidity

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Why is Removal of Siloxanes, H2S, VOC’s Critical?

➢ Increases maintenance costs

➢ Reduces amount of gas processed

➢ Reduces lifetime of equipment

➢ Regulations (pipelines / environmental)

Source

Removal of Siloxanes and H2S Significantly Reduces Operational Costs

Spark Plugs

source

Boiler Tubes

Biogas:

~ 60% Methane

~ 38 % CO2

~ 0-2% Oxygen

~ 1-500 ppm H2S

~ 1-10 ppm Siloxanes

~ 1-500 ppm VOCs

~ 5-20% RH

COMPLIANCE!

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Cabot-Norit Activated Carbon Product Portfolio for Biogas Purification

Raw Gas Composition

SiOx Species and concentration?

Grade Main Function

Darco BG1Efficient in the removal of H2S and some siloxanes –better on the purification of relatively low gas streams.

Darco BGH

Multiuse grade for H2S adsorption (and also some siloxanes in certain operational conditions). Highcapacity for H2S (reduced carbon bed change-out frequency) and VOC’s.

Norit RST

Pelletized grade, not impregnated, with catalytic properties and low pressure drop. Still needs presence of O2 and moisture for effective H2S adsorption. Efficient adsorption of VOC’s.

Norit RGM

Pelletized grade, impregnated, allowing H2S oxidation and transformation in elemental sulfur, thus efficient adsorption in the presence of low O2

concentrations in the gas.

Norit RB / Norit RBW

Cost-effective pelletized grades with low pressure drop. Standard line of carbons designed for effective removal of a wide range of SiOx’s and VOC’s.

Norit SILPURE

Premium pelletized carbon, designed for preferential removal of siloxanes (lower affinity for VOCs – allowing lower carbon change-out frequency and optimized operational costs).

VOC Species and concentration?

H2S, O2, Relative Humidity?

Flow? T? P? Treatment Process?

Desired Gas Specs After the Carbon?

Final Biogas Application? Engines?

Upgrade to biomethane? Other?

23 AUGUST 2017 / PRESENTATION TITLE / CONFIDENTIAL / NOT FOR REDISTRIBUTION 14

Activated Carbon Performance Data

Lab, Pilot and Industrial Trials

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Siloxanes Removal

Pore Size Distribution

Raw material Mineral / Veget.

Activation method

Steam / Chemical

Long Service Life / Less

Change Out

Pore Volume, Surface Area

Surface chemistry of AC

Preferential Adsorption

Fate of Spent Carbon

Non-Hazardous Waste

Heavy Metals in AC

Heavy Metals in Biogas

Easy Change Out

No Surface Reaction

Pressure Drop

Granular/

Extruded

Carbon

Toolbox for Enhanced Siloxanes Removal

Technical Capability – Gaps

• Collaborative Work with Universities and External Labs

No in House Capability to Measure Siloxane Adsorption

• Customer Trials – Field Validation

Biogas is a Complex Mixture to Mimic in Lab

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INLET

INLET

OUTLET

OUTLET

Preferential Desorption of VOCs!

Standard Carbon for Siloxanes and VOCs

Silpure

VOCs

Siloxanes

Hypothesis: Schematic for Preferential Affinity

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D4/Toluene Mixed Stream DataSTANDARD ACTIVATED CARBON #1

STANDARD ACTIVATED CARBON #2

Silpure

Silpure preferentially desorbs VOCs in the presence of D4

Impurity Conc.:

620-660 ppm D4

470-530 ppm Toluene

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Impurity Conc.:

403-453 ppm L2

452-499 ppm Toluene

L2/Toluene Mixed Stream Data

Silpure preferentially desorb VOCs in presence of L2

STANDARD ACTIVATED CARBON #1

STANDARD ACTIVATED CARBON #2

Silpure

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Silpure

Standard Activated Carbon #2

Different types of activated carbon show different breakthrough nature

Lets make Biogas in lab

Very high ppm level of impurities

Ratio based on typical Spanish landfill gas composition

Absolute concentration chosen to manipulate test time

Gas Composition:

L2: 70 ppm

Toluene : 1300 ppm

D4 : 630 ppm

Limonene: 200 ppm

D5: 650 ppm

Multi-stream Data: L2/D4/D5/Toluene/Limonene

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1• Silpure has a higher affinity for siloxanes

2• With Silpure, toluene preferentially desorbs in the

presence of siloxanes

3• Gas streams with numerous compounds are difficult to

model

Key Learning form Spanish Lab Data

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Industrial Trial 1 – USA Landfill

• Southern Landfill, DE (June 2016)

• Poor performance of traditional AC

• Hypothesis: high concentration of H2S/VOC saturated AC

• Raw gas has 500 ppm of H2S, 45 ppm of VOCs and 4 ppm siloxanes (95% TMS)

• Cabot proposed 2 carbon grades

Silpure 1584 lbs / Standard Carbon: 2381 lbs

• 1 Vessel in each bank filled with each product

• Flow 1300 SCFM (650 SCFM Splits in 2 banks)

• Gas sample collected everyday (inlet and 2 outlets)

• Gas samples analyzed to monitor carbon performance at the Centek Lab

Sample Collection

port

Inlet Gas

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Impurities Removal Summary

Silpure Standard Cabot-Norit Carbon

# of Vessels 1 3

# of pounds (total) 1584 2381

RawGas

Adsorbed % NOTAdsorbed

RawGas

Adsorbed % NotAdsorbed

Siloxanes (lbs) 15 15 0 10 8.9 11

VOCs (lbs) 116 40 66 87 62 30

H2S (lbs) 465 307 34 305 170 44

Total gas processed (MSCF)

14.1 9.4

# of days 15 10

Silpure captured 30% more siloxanes than Standard Carbon

Silpure desorbed 35% more VOC’s compared to Standard Carbon

1584 lbs Silpure processed 33% more gas compared to 2381 lbs of Standard Carbon

In comparison at equal weight, Silpure performs 50% better

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Performance Summary

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Industrial Trial 2 – UK Landfill

Norit® Silpure Competitive Carbon

# of Vessels 1 3

# of kgs 720 3000

RawGas

Adsorbed % Adsorbed RawGas

Adsorbed % Adsorbed

Siloxanes (kgs) 5.8 3.0 52 5.8 0.8 12

H2S (kgs) 123 112 91 123 25 22

Total gas processed (MM M3/27 days)

3.2 3.2 (Not considering downtime)

# of days 27 27

On an equal weight basis, Norit® Silpure removes 15x more siloxanes

UK landfill site: 5 engines operating in parallel

Gas contains siloxanes, VOC’s and ~350ppm of H2S

Flow rate ~500m3/hr per engine

Incumbent: 4 mm reactivated AC, 1000kg each vessel

Trial: One Norit Slpure Vessel with 720kg of AC

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Performance Summary

➢ Customer’s Target limit 10mg/m3 of Silicon from Siloxanes

➢ Competitive AC vessels kept exceeding the 10mg/m3 Si target

0

5

10

15

20

25

0 1 2 3 4 5 6 7

Silic

on

(Si

) m

g/m

3

Competitive AC Exchange Dates

Comp. AC 2-day4

Competitive AC 1-day 8

Comp. AC-day3

Competitive AC 3-day 10

Cabot 1-day 8

Cabot 1-day 12 Cabot 1-day 21

Cabot 1-day 27

Competitive AC 2 -day 9Estimates breakthrough time

30th May 7th June 16th June 26th June

Competitive AC

Cabot

Norit®Silpure lasted 15x more than competitive AC during trial period

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Norit Siloxane Index

The Norit Siloxane Index (NSI) is a measured value highly correlated to siloxane removal performance.

The NSI is a numerical outcome measuring the siloxanes’ adsorption capacity of a media under real life conditions.

NORIT® SILPURE activated carbon has an NSI of 100, higher than traditional coconut / bituminous carbons. In the same biogas stream NORIT SILPURE will remove 55% more siloxanes by weight vs. coconut and 50% more than coal based carbons.

100

45 50

0

20

40

60

80

100

120

Silpure Coconut Coal

No

rit

Silo

xan

e In

dex

NSI comparison for Silpure vs traditional activated carbon

Silpure

Coconut

Coal

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Benefits of the Novel Grade Norit Silpure

Optimized performance in the removal of all SiOx species,

including the most difficult ones such as L2 and TMS.

Surface chemistry allows preferential desorption of high

calorific power VOC’s, while all the SiOx’s are retained.

Reduced plant downtime, maximization of biogas/biomethane production.

Significantly lower CAPEX than alternative technologies for siloxanes removal.

Optimization of plants with limited gas flow available: Silpure shows long lifetime

(low bed change-out frequency / low OPEX), allowing continuous operation without

the use of valuable gas for vessel media regeneration.

Operational and maintenance costs optimization: reduction of engine cleansings in

70%, lub oil changes in 50%, and emission control (catalysts) in 50%.

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Industrial Trial 3 – H2S Removal from Landfill Gas

DARCO BGH DARCO BG1 Iron Oxide Media

Media Mass lbs. 58,500 73,125 195,000

Total Media Cost $102,375 $95,063 $146,250

Total Media Change Out Days 3.25 3.78 11.7

Total Change Out Cost $22,100 $25,720 $79,560

Total Customer Cost $124,475 $120,782 $225,810

Cost per lb. of H2S removed $5.32 $5.16 $9.65

Total customer savings $101,335 $105,028

Fewer Days of Downtime 8.45 7.92

Annual Customer Cost Comparison

Landfill • Have developed or constructed more

than 50 projects over the last 25 years • Currently owns 29 projects that generate

electricity, six that produce pipeline-quality gas, and provides operational and maintenance services to nine projects owned by third parties

• Estimated that gas generation will total more than 905 million MMBtu over the next 20 years.

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Performance Summary

Test intended to mimic real life field conditions

Darco BG1 is a non-impregnated catalytic carbon

Darco BG1 has 2x the life of impregnated competitors

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H2S Removal Performance

4.33.8

4.7

6.6

0.51.2

0.50.50.5

6.3

Potassium AC

Iron Oxide Media

Caustic AC

5.2

DARCO BG1

4.3

Darco BGH

4.7

7.17.4

O&M

Media

19%

32%

DARCO BGH

50%

23%

DARCO BG1

Potassium AC

Caustic AC Iron Oxide Media

12%

Competition

Cabot

H2S Loading Capacity % $ per lb. of H2S Removed

Muito Obrigado!

Tecnical Contact:

Pedro PaixãoApplications Mgr. – South America

Tel (11) 2144-6470pedro.paixao@cabotcorp.com

Commercial Contact:

Adriana RussiRegional Business Mgr.

Tel (11) 2144-6432adriana.russi@cabotcorp.com