2015-07-24_ Hassan Presentation - BFN (Final Presentation)

Comparative Assessment of Steam Processed pellets produced from wood, straw and switchgrass

S M HASSAN SHAHRUKH, ADETOYESE OYEDUN, AMIT KUMAR1, LINOJ KUMAR, BAHMAN GHIASI, SHAHAB

SOKHANSANJ2

1Department of Mechanical Engineering, University of AlbertaEdmonton, AB, Canada

2Department of Chemical and Biological Engineering, Vancouver, BC, Canada

ADVANCED BIOFUELS SYMPOSIUM July 22 - 24, 2015, Montreal, Canada

Presentation Outline Background and Objective Pellet Production Supply Chain Model Development and Validation Mass and Heat Balance of Steam

Pretreatment Techno-Economic Result Summary of Result

Presentation at BFN, 22-24 July, 2015

Background

Presentation at BFN, 22-24 July, 2015

• Pretreatment helps producing high quality pellets

• Energy density of regular pellets is 1/8th of coal

• High transportation cost of regular biomass and pellets

• Need for higher utilization of Biomass

Low Utilization Cost Issues

Pretreatment

Low Bulk and Energy density of

regular pellets

Objectives

Conduct Techno-Economic Assessment

Cost curves Sensitivity & uncertainty

Conduct Energy Analysis Net energy ratio (NER)

Sensitivity & uncertainty

Develop process model for steam pretreatment of wood, straw and switchgrassHeat and mass

balanceData intensive

modeling

Presentation at BFN, 22-24 July, 2015

Pellet Supply Chain

Biomass collectio

n

Bale formatio

n/ chipping

Transportation to

pellet plant

Pellet producti

on

Transportation of

pellet to biorefinery

Used in biorefinery

Supply chain of pellet to a biorefinery (Conventional method)

Used in biorefinery

Biomass

collection

Transportation to

pellet plant

Pellet Producti

on

Transportation of

pellet to biorefinery

Steam pretreatm

ent

Bale formation/chip

ping

Steam Pretreatm

ent

Supply chain of pellet (produced from pretreated biomass) to a biorefinery

Presentation at BFN, 22-24 July, 2015

Experimental Material and Method

Material

Wood, Straw ,Switchgrass

Moisture content ~ 10%-50%

Method

Pretreatment carried in 2.6L StakeTech

Steam gun with 400g of biomass treated at different temperature

and time

Steam treated biomass pelletized

Presentation at BFN, 22-24 July, 2015

Model Input and Validation

1. Boiler unit: Supply of steam at different time and

temperature2. Time: 10 min

3. Temperature: 180-210⁰C

2. Steam Pretreatment Unit: Biomass

is treated with high pressure steam in batch

reactor (Yield reactor considered)

logR = logනexp(T− 10014.75 )dt Governing Equation:

Source: Lam et al. 2013

Presentation at BFN, 22-24 July, 2015

Model Input and Validation

3. Pellet mill: produces pellet of

20-30 mm long, 6 mm in diameter, has a heating element

operating at 70-100 C.

2. Grinder: Kicks energy constant 100KJ/kg, solid recovery 95%

1. Dryer: operating temperature at

80 C.

Presentation at ASABE, 26-29 July,2015

No grinder is required for pellet production of straw and switchgrass

Model Validation Result

Operation

Experimental Energy Consumption (kJ)

ASPEN model Predicted Energy Consumption (kJ)

Wood Straw SG Wood Straw SG

Steam Pretreatment 2097 749 678 2095 760 710

Drying 6162 6731 8979 6156 6951 9045

Size reduction 15 0 0 17 0 0

Pelletization 492 330 318 500 352 325

Presentation at BFN, 22-24 July,2015

Comparative Heat and Mass Balance

Presentation at BFN, 22-24 July,2015

Wood

A. Regular Pellet

B. Steam Pretreated Pellet

Dryer Hammer

Mill Pellet Mill

2.4 kg

0.63 kg

0.58 kg

0.54 kg

19.6 MJ

1 kg

2.1 MJ

6.2 MJ

0.01 MJ

0.45 MJ

Dryer Hammer Mill

Pellet Mill

1 kg

0.7 kg

0.65 kg

0.61 kg

18 MJ

1.3 MJ

0.2 MJ

0.5 MJ

Comparative Heat and Mass Balance (Cont’d)

Presentation at BFN, 22-24 July,2015

Dryer Hammer Mill

Pellet Mill

1kg

0.95 kg

0.92kg

0.85 kg

17 MJ

0 MJ

0.3MJ

0.8 MJ

Dryer Hammer Mill

Pellet Mill

1kg

0.95 kg

0.92kg

0.88 kg

17 MJ

0 MJ

0.3MJ

0.8 MJ

Straw Switchgrass

A. Regular Pellet A. Regular Pellet

B. Steam Pretreated Pellet B. Steam Pretreated Pellet

Dryer Hammer

Mill Pellet Mill

3.0 kg

0.8 kg

0.8kg

0.72 kg

19 MJ

1kg

0.8MJ

6.7 MJ

0 MJ

0.42 MJ

Dryer Hammer

Mill Pellet Mill

3.4 kg

0.8 kg

0.8kg

0.71 kg

19.1 MJ

1kg

0.7MJ

8.9 MJ

0 MJ

0.4 MJ

Variation of NER with Pretreatment Temperature and Level

Presentation at BFN, 22-24 July,2015

0

0.5

1

1.5

2

2.5

3

140 160 180

NER

Steam Pretreatment Temperature

Straw Switchgrass

-

1.00

2.00

3.00

4.00

5.00

6.00

7.00

25% 50% 75%

NER

Pretreatment level

Wood Straw SG

Uncertainty Analysis

Presentation at BFN, 22-24 July,2015

Straw Switchgrass

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

Prob

abili

ty

1.1 1.2 1.3 1.4 1.5 1.6 1.7NER

5% 90% 5%

5%(x = 1.21) 95%(x = 1.49)

Wood

Techno-Economic Snapshot

Presentation at BFN 22-24 July,2015

  Straw Forest residue SwitchgrassRegular Steam

pretreatedRegular Steam

pretreatedRegular Steam

pretreatedOptimum size (t year-1)

190,000 250,000 190,000 290,000 190,000 230,000

Pellet cost ($ t-1) 122.04 188.34 116.01 183.14 116.20 192.41-Capital recovery 9.56 15.31 10.83 20.34 13.74 21.53- Maintenance cost 2.64 3.68 2.34 3.59 2.58 3.76-Field cost 52.34 58.75 28.19 32.08 25.57 29.39-Transportation cost 33.89 42.99 37.04 50.24 45.38 57.68-Premium 0.00 0.00 6.39 5.50 5.34 6.13-Employee cost 7.27 7.85 6.58 6.76 7.27 8.53-Energy cost 5.41 48.91 14.74 53.79 5.41 54.50-Consumable item cost

10.93 10.86 9.90 10.84 10.93 10.88

Pellet transportation 6.30 5.50 6.20 5.45 6.80 6.10Total pellet delivery cost

128.34 193.84 122.21 188.59 123.00 198.51

Variation of Transportation Cost

Presentation at BFN, 22-24 July, 2015

Variation of Capital Cost

Presentation at BFN, 22-24 July, 2015

Variation in Production Cost

Presentation at BFN, 22-24 July,2015

Sensitivity Analysis - Wood

Presentation at BFN, 22-24 July,2015

-20.00% -10.00% 0.00% 10.00% 20.00%174.00

179.00

184.00

189.00

194.00

199.00

capital cost employee cost

Energy cost Transportation cost

Field cost consumable cost

% change

Prod

uctio

n C

ost,

$ \ t

-20.00% -10.00% 0.00% 10.00% 20.00%180.00

182.00

184.00

186.00

188.00

190.00

192.00

194.00

Moisture content Feed stock material loss

Inflation IRR

% area

Pro

duct

ion

Cos

t, $\

t

Sensitivity Analysis - Straw

Presentation at BFN, 22-24 July,2015

-20.00% -10.00% 0.00% 10.00% 20.00%180.00

185.00

190.00

195.00

200.00

205.00

capital cost employee costEnergy cost Transportation costField cost consumable cost

% change

Tota

l cos

t of p

elle

t ($(

t)-1

)

-20.00% -10.00% 0.00% 10.00% 20.00%188.00

190.00

192.00

194.00

196.00

198.00

200.00

Moisture content Feed stock material loss Inflation IRR% area

% change

Tot

al c

ost o

f pel

let p

rodu

ctio

n($(

t)-1

)

Sensitivity Analysis - Switchgrass

Presentation at BFN, 22-24 July,2015

-20.00% -10.00% 0.00% 10.00% 20.00%186.00

191.00

196.00

201.00

206.00

capital cost employee costEnergy cost Transportation costField cost consumable cost

% change

Tota

l cos

t of p

elle

t ($(

t)-1)

-20.00% -10.00% 0.00% 10.00% 20.00%193.00

194.00

195.00

196.00

197.00

198.00

199.00

200.00

201.00

202.00

203.00

Moisture content Feed stock material loss

Inflation IRR

% area

% change

Tot

al c

ost o

f pel

let p

rodu

ctio

n($(

t)-1

)

Uncertainty Analysis

Presentation at BFN, 22-24 July,2015

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

Prob

abili

ty

230 235 240 245 250 255 260 265 270 275Pellet Cost ($/tonne)

5% 90% 5%

5%(x = 236.39) 95%(x = 261.8)

Straw0.00

0.01

0.02

0.03

0.04

0.05

0.06

Prob

abili

ty

230 235 240 245 250 255 260 265 270 275Pellet Cost ($/tonne)

5% 90.005% 4.995%

5%(x = 237.93) 95.005%(x = 258.65)

Switchgrass

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

Prob

abili

ty

220 225 230 235 240 245 250 255Pellet Cost ($/tonne)

4.995% 90.00999% 4.995%

4.995%(x = 228.37) 95.005%(x = 247.11)

Wood

Summary of Result

Energy

• Energy ratio of regular pelletization process is higher than steam pretreated pellet due to addition of steam as energy source

• Calorific value of pellet increases by 21% due to steam pretreatment

• Grinding energy input is zero for straw and switchgrass

Cost

• $/tonne cost of production for steam pretreated pellet is higher than regular pellet due to increased capital cost

• $/GJ cost production of pellet for both steam treated pellet and regular pellet is similar with approximately 30 cents difference

Scaling

• Steam pretreatment is more effective over a plant size of 270,000 tonnes/yr plant capacity due to economy of scale benefits based on $/GJ

Presentation at BFN 22-24 July, 2015

AcknowledgementBio Fuel Net

University of Alberta

Dr. Shahab Sokhansanj, Dr. Linoj Kumar and Bahman Ghiasi, Department of Chemical Engineering, University of British Columbia

Presentation at BFN 22-24 July,2015

THANKS

Contact Information:

Dr. AMIT KUMAR

Professor

NSERC/Cenovus/Alberta Innovates Associate Industrial Research Chair in Energy and

Environmental Systems Engineering

Cenovus Energy Endowed Chair in Environmental Engineering

Department of Mechanical Engineering, University of Alberta

Amit.kumar@ualberta.ca

www.energysystems.ualberta.ca

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