Bioeconomy Institute TCS 2015: Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products

Nov 2015 - Chicago, IL

• By incorporating ethanol, AC, and lower-cost sustainable biomass this

model saw a significant improvement in IRR of up to 16% compared to

previous TEA.

• The commercialization of 31 million gallons of transportation fuels,

activated carbon and hydrogen production resulted in a gross revenue of

$154 million a year from a total project investment of $414 million.

• There are major risks associated with this and other technologies that are

not technically mature, which require several years to optimize the

process and develop value added products from each stream. However,

this study provides positive preliminary results from the integration of a

thermochemical and biological biorefinery.

Bernardo G. del Campo, Mark MBA Wright & Robert C. Brown

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The successful development of large scale commercial biorefineries depends on the

effective integration of different pathways for the production of multiple coproducts.

Two new process modules were integrated to previous biorefinery models.

These modules consist of the production of activated carbon from low value

biochar and the fermentation of bio-oil’s pyrolytic sugars into ethanol.

Laboratory experiments were performed to validate and optimize the

production of activated carbon (AC), as well as to maximize the ethanol production

from pyrolytic sugars and remove inhibitory compounds present in the raw bio-oil.

Funding and support provided by the Iowa Energy Center

Table: Fast pyrolysis output stream

Plant capacity (dry corn stover) 780,934 ton/year 2,000 ton/day

Pyrolysis co-products

Bio-oil (62% wt) 481,056 ton/year 1,232 ton/day

Biochar (21% wt) 167,120 ton/year 428 ton/day

NC-Gases (17% wt) 132,759 ton/year 340 ton/day

Figure: General outline of the biorefinery components: biomass pretreatment, fast pyrolysis,

activation, fermentation, hydrotreating and combustion modules.

Figure: ASPEN plus process design

integrating the fuel production modules.

Figure: Sensitivity analysis for a 2000 ton per day fast pyrolysis biorefinery

Figure: Internal rate of return with varying AC (left) and hydrogen (right) selling price.

Figure: Annual operating costs and equipment costs for a 2000 tons per day biorefinery

Energy in Quantity used Energy distribution MM$/yr

Biomass 2000 ton/day 398 MW 89% $ 39

Natural Gas 59 ton/day 38 MW 8% $ 6

electricity 14 MW 14 MW 3% $ 7

Total 449 MW 100% $ 52

Energy out Quantity produced Energy distribution MM$/yr

Gasoline & diesel sales 17 MM gal/year 65 MW 34% $ 51

Ethanol sales 14 MM gal/year 37 MW 19% $ 29

H2 sales 9 MM Kg/year 33 MW 17% $ 30

Activated char sales 67 MM Kg/year 58 MW 30% $ 44

Total 193 MW 100% $ 154

Table: Energy inputs and outputs of the system

Product stream Volume of product sales MM$/yr Percent Sales

Gasoline & diesel sales 16.93 MM gal/year 47808 gal/day $ 51 33%

Ethanol sales 14.38 MM gal/year 40601 gal/day $ 29 19%

Hydrogen sales 8.68 MM Kg/year 24505 Kg/day $ 30 20%

Activated char sales 66.66 MM Kg/year 188212 Kg/day $ 44 28%

Total $ 154 100%

Table: Product sales and general revenue

Natural gas price (5MMBTU ±25%)

Electricity cost (0.06 $/kwh ±25%)

Working Capital (±25%)

Income Tax Rate (49:39:29%)

Hydrogen price ($3.49/ton ±25%)

Ethanol selling price ($2.00/gal ±25%)

Activated char selling price ($656/ton ±25%)

Gasoline price ($3.00/gal ±25%)

Feedstock cost (75:50:25 $/ton)

Total Fixed Capital Investment (±25%)

IRR (%)

Unfavorable; Base Case and Favorable scenarios

FavorableUnfavorable

y = -2E-08x2 + 0.0002x + 0.0373

0%

10%

20%

30%

40%

50%

0 1000 2000 3000

AC price ($ per metric ton)

y = 0.0233x + 0.0765

0%

5%

10%

15%

20%

25%

0 1 2 3 4 5

IRR

(%

)

Hydrogen selling price ($ per Kg)

71

57

35

26

25

18 7

$0

$50

$100

$150

$200

$250

Equ

ipm

en

t C

ost

s ($

MM

)

Extraction

Storage

Utilities

Fermentation

Pyrolysis & Oil Recovery Pretreatment

Combustion

Hydroprocessing

39

19

17

12.8

7

$0

$20

$40

$60

$80

$100

An

nu

al O

pe

rati

ng

Co

sts

($M

M)

Waste Disposal

Utilities

Other raw materials

Electricity

Average Income Tax

Fixed Costs

Capital Depreciation

Feedstock

The goal of this study was to quantify the economic internal rate of return of

a fast pyrolysis, corn stover biorefinery by incorporating the detoxification and

fermentation of pyrolytic sugars, and production of AC from biochar.

Similar to traditional fast pyrolysis systems, the first module is the

pretreatment stage comprised of three stages: hammer mill for size reduction,

sulfuric acid is added, and a rotary drier lowers the moisture to 10%wt.

The biomass is pyrolyzed at 500ºC

on a fluidized bed to produce bio-

oil, biochar and pyrolysis gases

(62, 21 & 17% respectively).

• Chemisorption and functional attributes should be studied to identify

different uses and applications of activated biochars.

TECHNO-ECONOMIC ANALYSIS OF A BIOREFINERY INTEGRATING ACTIVATED CARBON AND ETHANOL FROM PYROLYTIC SUGARS

IRR

(%

)