Thermal Conversion of Solid Wastes and Biomass - American

3 Preliminary Economic Overview of Large-ScaleThermal Conversion Systems Using Wood Feedstocks

Downloaded by UNIV OF LIVERPOOL on May 14, 2018 | https://pubs.acs.org Publication Date: August 29, 1980 | doi: 10.1021/bk-1980-0130.ch003

STEPHEN M. KOHAN Electric Power Research Institute, 3412 Hillview Avenue, Palo Alto, CA 94303 This paper presents a brief overview of the economics of conceptual technical schemes to convert woody biomass feedstocks into other, more useful energy and chemical forms. It is becoming increasingly clear that no single solution exists to the recurring domestic energy crisis. Rather, regional energy supplies (some renewable, some non-renewable) together with end-use energy management practices, are likely to play important roles in achieving stated national goals of energy self-sufficiency. Wood is a regional, renewable resource. DOE's Fuels from Biomass Branch is keenly interested in maximizing the cost-effective contribution of wood energy (as well as other forms of biomass) to the nation's energy supply. DOE awarded SRI International a contract (EY-76-C-03-0115 PA 131) in late 1977 to assist DOE in determining promising biomass feedstock/conversion technology/ product options for purposes of R&D program planning. This paper briefly reviews the data base for biomass thermal conversion technologies developed as a necessary part of this program planning effort. This analysis employs uniform design and economic bases. These are briefly reviewed, followed by summary economics for the production from wood of electricity, steam, and cogenerated products; intermediate-Btu gas (IBG) and substitute natural gas (SNG); methanol; ammonia; fuel o i l ; and pyrolytic o i l and char. Several processing steps in these conversion schemes are conceptual or are at early stages of development by DOE, EPRI, GRI, and others (an exception would be wood steam/electric power plants, which are commercially used by the electric utility and wood products industries). Consequently, the economics presented here may generally tend to be optimistic. Additional details of the analyses can be found in Kohan and Barkhordar(1); Jones, Kohan and Semrau(2); and Kohan and Dickenson(3) · Design Bases The base wood feedstock rate used i n the study i s 1.8x10 kg/d

0-8412-0565-5/80/47-130-029$05.00/0 © 1980 American Chemical Society Jones and Radding; Thermal Conversion of Solid Wastes and Biomass ACS Symposium Series; American Chemical Society: Washington, DC, 1980.

THERMAL CONVERSION OF SOLID WASTES AND BIOMASS

30

(2000 ST/d) o f green (50 wt% moisture) wood. T h i s value was s e l e c t e d as r e p r e s e n t i n g a near-term product i o n g o a l . Product cost s e n s i t i v i t i e s over feedstock r a t e s of 0.9xl0 kg/d to 5.4xl0 kg/d of green wood are presented by Kohan and Barkhordar(1). The dry wood energy content i s 22,200 KJ/kg. P l a n t designs are g e n e r a l l y s e l f - s u f f i c i e n t i n terms o f purchased energy (e.g., e l e c t r i c i t y ) needs. T h i r t y days feedstock storage i s provided o n - s i t e . 6

6

1


Economic Bases Reference(1) d e t a i l s the economic bases f o r the a n a l y s i s . These are summarized below. A l a t e 1977 cost b a s i s i s used. The p l a n t f a c i l i t i e s i n v e s t ment represents the c a p i t a l c o s t o f the p l a n t as e r e c t e d and awaiting s t a r t - u p . C o n s t a n t - d o l l a r economics are used. Plant c o n s t r u c t i o n periods range from 2 to 4 years, depending on p l a n t complexity. S i t e - s p e c i f i c investments (e.g., townsites) and across-the-board contingency f a c t o r s are excluded from the analysis . C o n s t a n t - d o l l a r economics are l i k e w i s e used f o r the c a l c u l a t i o n o f product revenue requirements. Two i l l u s t r a t i v e f i n a n c i n g extremes are considered: r e g u l a t e d u t i l i t y , i n which c a p i t a l recovery f a c t o r s are low and product markets would be non-competitive ; and non-regulated i n d u s t r i a l , i n which c a p i t a l recovery f a c t o r s are high and product markets would be competive. For r e g u l a t e d u t i l i t y f i n a n c i n g , a d e c l i n i n g rate base a n a l y s i s i s used, with the f o l l o w i n g f i n a n c i a l parameters: 65% debt c a p i t a l ; 9% i n t e r e s t r a t e on a 20-year loan; 15% r e t u r n on equity c a p i t a l ; 10% i n t e r e s t r a t e during c o n s t r u c t i o n ; s t r a i g h t l i n e d e p r e c i a t i o n ; and 52% f e d e r a l and s t a t e corporate tax r a t e . For non-regulated i n d u s t r i a l f i n a n c i n g , a discounted cash flow (DCF) a n a l y s i s i s used, with the f o l l o w i n g f i n a n c i a l parameters; 100% e q u i t y c a p i t a l ; 15 y e a r p l a n t tax l i f e ; 15% DCF r e t u r n ; a c c e l e r a t e d d e p r e c i a t i o n ; and 52% f e d e r a l and s t a t e corporate tax r a t e . The c o s t of wood d e l i v e r e d to the conversion f a c i l i t y i s assumed to be $0.95/GJ ($21/dry metric t o n ) . E l e c t r i c i t y , Steam, and Cogenerated Products Wood combustion to produce heat, steam, and e l e c t r i c i t y i s an o l d a r t . R i s i n g o i l f u e l costs and other r e g i o n a l f a c t o r s are causing u t i l i t i e s such as B u r l i n g t o n E l e c t r i c Co., Consumers Power, P o r t l a n d General E l e c t r i c , and others to s e r i o u s l y consider i n s t a l l i n g 40-50 MW wood-fired s t e a m / e l e c t r i c p l a n t s . P a c i f i c Gas and E l e c t r i c , the Eugene Water and E l e c t r i c Board, and others are c o n s i d e r i n g r e g i o n a l i n d u s t r i a l j o i n t ventures i n v o l v i n g cogenerat i o n (the simultaneous generation o f e l e c t r i c i t y and steam) . Table I presents the estimated investment i n new, grass-roots f a c i l i t i e s f o r the production of e l e c t r i c i t y , steam, or both pro-

Jones and Radding; Thermal Conversion of Solid Wastes and Biomass ACS Symposium Series; American Chemical Society: Washington, DC, 1980.


3.

KOHAN

Economics of Conversion Using Wood Feedstocks

31

Table I WOOD COMBUSTION FACILITIES - ESTIMATED INVESTMENT

Principal Product

Product:

Rate:

Plant Financing:

Investment,

Electricity

Steam

49.6 MWh/h

217,060kg/h

Regulated Utility

Non-Regulated Industrial

Cogeneration 12 1 15.3x10 J / d Regulated Utility

M i l l i o n s o f Dollars(1977)

Plant F a c i l i t i e s

Investment

51.1

27.9

35.1

Land

0.5

0.5

0.5

O r g a n i z a t i o n , S t a r t u p Expenses

1.5

0.8

1.1

I n t e r e s t During C o n s t r u c t i o n

3.5

Working

1.6

1.2

1.2

58.2

30.4

40.3

Capital

Total Capital

Investment

2.4

"^Total Product B a s i s Basis:

1.8 χ 10

kg/d green wood

(50 wt.% moisture)

feed rate



32

THERMAL CONVERSION

OF SOLID WASTES AND BIOMASS

ducts. The investment i n the steam-producing f a c i l i t i e s (non-reg u l a t e d i n d u s t r i a l f i n a n c i n g ) i s about h a l f o f t h a t i n the e l e c t r i c power p l a n t because t u r b i n e - g e n e r a t o r , steam condensing and c o o l i n g tower f a c i l i t i e s are omitted. The investment i n cogenera t i o n f a c i l i t i e s i s about midway between the other two investments because t u r b i n e - g e n e r a t o r f a c i l i t i e s are i n c l u d e d but steam condensing and c o o l i n g tower f a c i l i t i e s are omitted. The cogenerat i o n p l a n t produces about 7 MW of e l e c t r i c power. For the e l e c t r i c power case, the p l a n t f a c i l i t i e s investment of $51.1 m i l l i o n i s about $1030/kW which i s i n reasonable agreeement with o t h e r p u b l i s h e d estimates. Table I I shows the estimated revenue requirements. Electric i t y and cogenerated products costs are based on r e g u l a t e d u t i l i t y f i n a n c i n g , while steam costs are based on non-regulated i n d u s t r i a l f i n a n c i n g . The cogeneration case costs are shown on a t o t a l product b a s i s , s i n c e two products are i n v o l v e d . F i g u r e 1 shows the s e l l i n g p r i c e o f e l e c t r i c i t y as a f u n c t i o n o f the s e l l i n g p r i c e of steam f o r the cogeneration case. The p r i c e s o f products from wood combustion appear to be h i g h e r than t h e i r counterparts from c o a l combustion. A contribut i n g reason may be the s m a l l e r s i z e s o f the wood f a c i l i t i e s cont r a s t e d with " t y p i c a l " c o a l f a c i l i t i e s (e.g., 50 MW f o r wood power p l a n t s ; 500-1000 MW f o r conventional c o a l power p l a n t s ) . Figure 2 shows the e f f e c t of wood c o s t and p l a n t c a p a c i t y on e l e c t r i c i t y c o s t . As p l a n t s i z e s i n c r e a s e from 25 to 150 MW, e l e c t r i c i t y costs f a l l by 10 to 20 percent, r e f l e c t i n g some economies o f s c a l e . Kohan and Barkhordar(1) present analogous sens i t i v i t y curves f o r other products evaluated i n t h i s study. Wood G a s i f i c a t i o n Wood g a s i f i c a t i o n i n s m a l l , fixed-bed producers was widely p r a c t i c e d i n the U.S. and Europe i n the e a r l y 1900's. Today, the Fuels from Biomass Branch o f the Department o f Energy i s sponsoring the development o f s e v e r a l g e n e r i c a l l y d i f f e r e n t g a s i f i c a t i o n systems designed to e x p l o i t the h i g h e r r e a c t i v i t y o f ( h i g h - a l k a l i n e - c o n t e n t ash) wood as c o n t r a s t e d with c o a l . This f i e l d i s r a p i d l y e v l o v i n g . For the present study, a conceptual, h i g h p r e s s u r e , non c a t a l y t i c , oxygen-blower f l u i d i z e d bed g a s i f i e r was s e l e c t e d f o r a n a l y s i s . References (1) and (3) present a d d i t i o n a l gasifier details. Table I I I presents the estimated investments f o r the product i o n o f high pressure (2100 kPa) intermediate Btu gas (IBG) and SNG from wood. Because o f the low s u l f u r content o f wood, no s u l f u r removal f a c i l i t i e s are i n c l u d e d i n the IBG design. Since the methanation c a t a l y s t i s s u l f u r - s e n s i t i v e , s u l f u r i n the synt h e s i s gas i n the SNG case i s removed down to very low l e v e l s . The estimated product r a t e s f o r IBG and SNG are s i g n i f i c a n t l y lower than corresponding p r o d u c t i o n r a t e s from " t y p i c a l " c o a l f a c i l t i e s (e.g., 2 6 0 x l O J/d SNG from c o a l ) . l2


KOHAN

3.

33


Table I I WOOD COMBUSTION FACILITIES

Principal

- PRODUCT REVENUE REQUIREMENTS

Electricity

Product:

Steam

Cogeneration

$/GJ

$/GJ

mills/kWh 16.0

1.23

1.25

Labor-Related

8.7

0.36

0.52

Purchased

6.6

0.28

0.25

Fixed Costs

6.6

0.25

0.35

P l a n t D e p r e c i a t i o n (20-yr)

8.1

0.44

14.5

0.79


Feedstock @ $0.95/GJ

Materials

2 Return on Rate Base & Income Tax C a p i t a l Charges

1.66

f o r a 15% DCF Return 60. 5

3.78(2.99)"

2

Total "'"Total P r o d u c t B a s i s 2 20-Year Average Values "^Regulated U t i l i t y F i n a n c i n g Basis: 1.8 χ 10^ kg/d green wood (50 wt.% moisture)

feed rate

Table I I I WOOD GASIFICATION FACILITIES

Principal

Product:

High-Pressure I n t e r m e d i a t e - B t u Gas(IBG) 14.3

P r o d u c t Rate :

χ 10

Regulated

Plant Financing Investment,

- ESTIMATED INVESTMENT

1 2

Substitute Natural Gas(SNG) 12.7

J/d

χ 10

Regulated

Utility



Investment

48.9

80.3

1

Land

0.3

0.3


2.4

4.0


3.7

6.1

Working C a p i t a l

1.5

2.0

56.8

92.7

T o t a l C a p i t a l Investment

"'"Decreases t o $39.5 m i l l i o n f o r low-pressure IBG p r o d u c t i o n Basis:

1.8 χ 10 kg/d green wood

(50 wt.% moisture)

feed rate


1 2

J/d

Utility



3.00

3.50

4.00

S E L L I N G PRICE OF S T E A M —

4.50

5.00

5.50

dollars per million B t u

Figure 1. Production of electricity and steam (cogeneration) by wood combustion —selling price of electricity as a function of selling price of steam



KOHAN


eu

ο

$38 ($2.00)

oc Ο

70

LU

Feedstock Cost, $/DT ($/MMBtu)

_] LU

S 60 $19($1.00)

2 50 Ε

40

Basis: Hours Per Year of Operation: Plant Life: 20 Years

30

7008

Ο Base Case

Applicable metric conversions: 1 Btu = 1055 J 1 short ton = 907.2 kg

_J 500

25

50 NET ENERGY OUTPUT

Figure 2.

I

1000 1500 2000 2500 PLANT CAPACITY — dry short tons per day of wood

100 — megawatts

3000

150

Production of electricity by wood combustion—effect of plant size on revenue required from the sale of electricity by a regulated utility



36


Table IV presents estimated revenue requirements f o r IBG and SNG u s i n g r e g u l a t e d u t i l i t y f i n a n c i n g . The low pressure a l t e r n a t i v e case shown f o r IBG produces 200 KPa (30 psig) pressure gas, which i s s u i t e d only f o r across-the-fence s a l e s to a u t i l i t y o r i n d u s t r i a l customer. The wood-derived gas product p r i c e s are h i g h e r than t h e i r c o a l - d e r i v e d gas counterparts p a r t i a l l y f o r reasons o f gas p r o d u c t i o n r a t e s . The costs o f producing IBG from wood may be 15 t o 50 p e r c e n t g r e a t e r than t h a t o f producing IBG from advanced c o a l g a s i f i c a t i o n t e c h n o l o g i e s ; and 80 to 100% g r e a t e r when c o n s i d e r i n g the p r o d u c t i o n o f SNG. C a t a l y t i c wood g a s i f i c a t i o n concepts b e i n g developed by B a t t e l l e Columbus Laborat o r i e s , B a t t e l l e P a c i f i c Northwest L a b o r a t o r i e s , and others may o f f e r the p o t e n t i a l to s i g n i f i c a n t l y reduce the costs o f biomass o r wood g a s i f i c a t i o n . L i q u i d Fuels Production L i q u i d f u e l s p r o d u c i b l e by thermal conversion o f biomass i n c l u d e f u e l o i l , p y r o l y s i s o i l s , methanol (discussed under chemic a l s p r o d u c t i o n ) , and o t h e r s . T h i s s e c t i o n d i s c u s s e s the product i o n o f f u e l o i l s and p y r o l y s i s o i l s from wood. The concept f o r f u e l o i l p r o d u c t i o n from wood i n v o l v e s the c a t a l y z e d removal o f oxygen from the wood molecules by reducing gases ( H , CO) a t e l e v a t e d temperatures and p r e s s u r e s . DOE i s developing t h i s concept a t a p i l o t f a c i l i t y (2700 kg/d wood feed rate) a t Albany, Oregon. Recent experimental work by Lawrence Berkeley Laboratory personnel suggests t h a t the wood feedstock should be p r e t r e a t e d by m i l d a c i d h y d r o l y s i s before conversion. The economics presented below do not i n c l u d e costs f o r the p r e t r e a t i n g step s i n c e t h i s i n f o r m a t i o n was not a v a i l a b l e when these analyses were conducted. P y r o l y s i s i n v o l v e s the decomposition o f o r g a n i c matter i n the absence o f oxygen. P y r o l y s i s i s widely p r a c t i c e d i n v a r i o u s i n d u s t r i e s (delayed coking i n petroleum r e f i n i n g ; batch coking o f c o a l i n the manufacture o f i r o n and s t e e l ) . The U.S. Environment a l P r o t e c t i o n Agency i s sponsoring the development o f p y r o l y s i s technologies aimed a t d i s p o s a l o f wastes and residues (both c e l l u l o s i c and n o n - c e l l u l o s i c ) . Large amounts o f co-product char i s produced during p y r o l y s i s , and process economics are h e a v i l y dependent on the value a s s i g n a b l e t o the char. The conversion f a c i l i t y design i n the p r e s e n t a n a l y s i s was p a t t e r n e d a f t e r the Tech-Air technology because the technology had been developed t o commercial prototype s i z e (45,000 dry kg/day) and because o f the a v a i l a b i l i t y o f p l a n t data. (Becent i n f o r m a t i o n suggests t h a t the commercial prototype p l a n t has been decommissioned). 2

P y r o l y t i c o i l s are a c i d i c and may c o n t a i n carcinogens. By analogy with heavy petroleum-derived o i l f r a c t i o n s , the f u e l o i l s produced by c a t a l y t i c l i q u e f a c t i o n may contain carcinogens. This suggests the need f o r s p e c i a l h a n d l i n g and storage p r e c a u t i o n s f o r the l i q u i d f u e l s . Table V presents the estimated investments f o r producing


KOHAN

3.


37

T a b l e IV WOOD GASIFICATION FACILITIES


P r i n c i p a l Product:

- PRODUCT REVENUE

REQUIREMENTS

I n t e r m e d i a t e - B t u Gas High-Pressure Low P r e s s u r e $/GJ $/GJ

SNG $/GJ


1.33

1.19

1.51

Labor-Related

0 .60

0.78

1.08

Purchased

0.26

0.18

0.62

0.46

0. 34

0.86

0.59

0.42

1.07

1.03

0.77

1.91

4.27

3.68

7.05

(5.97)

(4.93)

Materials

Fixed Costs P l a n t D e p r e c i a t i o n (20-yr) Return on Rate Base & Income T a x

1

Total-Regulated U t i l i t y F i n a n c i n g (Total-Nonregulated Financing)

1

1

Industrial (10.18)

2 0 - Y e a r Average V a l u e s

Basis:

1.8 χ 10^ kg/d green wood (50 wt.% moisture)

feed rate

Table V LIQUID FUELS PRODUCTION FROM WOOD - ESTIMATED INVESTMENT

P r i n c i p a l Product: P r o d u c t Rate:

Fuel O i l (Catalytic Liguef.) 11.0 χ 1 0

Plant Financing: Investment.

1 2

Pyrolytic Oil.Char

3

J / d (278m /d)

Regulated U t i l i t y

14.9 χ 1 0

1 2

Regulated



Investment

48.5

18.1

Land

0.3

0.3

O r g a n i z a t i o n , S t a r t u p Expense

2.4

0.9


3.7

1.4


1.8

1.5

T o t a l C a p i t a l Investment

1

56.7

22.2

T o t a l P r o d u c t B a s i s (45% o i l , 55% char)

Basis:

6

1.8 χ 1 0 kg/d green wood (50 wt.% moisture)

feed rate


J/d

1

Utility


38

l i q u i d f u e l s from wood. The p l a n t design f o r f u e l o i l p r o d u c t i o n i n v o l v e s high-pressure and-temperature s l u r r y r e c y c l e concepts and wood g a s i f i c a t i o n to produce the r e a c t a n t gases. The p y r o l y s i s concepts i n v o l v e low-pressure f i x e d bed p y r o l y s i s , w i t h a l l o f the p y r o l y t i c gases burned o n - s i t e f o r wood d r y i n g and p l a n t power needs. P y r o l y s i s investment costs are i n agreement with those presented by Jones(4). Normalized p l a n t investment costs o f $175,000 p e r d a i l y m f o r f u e l o i l p r o d u c t i o n exceed the $95,000 to $125,000 p e r d a i l y m values estimated f o r the p r o d u c t i o n o f s y n t h e t i c f u e l o i l from c o a l . A c o n t r i b u t i n g reason i s the s i g n i f i c a n t d i f f e r e n c e i n o i l p r o d u c t i o n r a t e s (278 m /d f o r woodd e r i v e d o i l ; 400 t o 800 m /d f o r c o a l - d e r i v e d o i l ) . Table VI shows the estimated revenue requirements using regul a t e d u t i l i t y f i n a n c i n g . Costs f o r the p y r o l y s i s case are shown on a t o t a l product b a s i s , s i n c e two products are i n v o l v e d . Figure 3 shows the s e l l i n g p r i c e o f the p y r o l y t i c o i l as a funct i o n o f the s e l l i n g p r i c e o f the char. The char i s low i n s u l f u r , n i t r o g e n , and ash, and may f i n d a p p l i c a t i o n s as a compliance b o i l e r f u e l , i n water p u r i f i c a t i o n , and so f o r t h . Char market values were not e s t a b l i s h e d f o r t h i s study. The p r i c e s o f wood-derived l i q u i d s appear to be h i g h e r than prices of similar coal-derived liquids. A c o n t r i b u t i n g reason may be the lower p r o d u c t i o n rates from the wood f a c i l i t i e s than from the c o a l f a c i l i t i e s . 3

3

3


3

Chemicals

Production

This s e c t i o n discusses the p r o d u c t i o n o f methanol and ammonia from wood. Methanol i s a clean-burning m a t e r i a l t h a t may f i n d widespread f u t u r e use as an automotive f u e l ( d i r e c t l y o r f o r conversion to g a s o l i n e by the Mobil p r o c e s s ) ; as a f u e l f o r indust r i a l o r u t i l i t y b o i l e r s , gas t u r b i n e s , o r f u e l c e l l s ; as a chemic a l i n t e r m e d i a t e ; o r as a b i o l o g i c a l feedstock f o r p r o t e i n . Ammonia i s an e s s e n t i a l b u i l d i n g block f o r s y n t h e t i c n i t r o g e n f e r t i l i z e r s and f i n d s widespread use i n the p r o d u c t i o n o f synthet i c fibers, explosives, a n a p l a s t i c s . The p r o d u c t i o n o f methanol and ammonia from wood i n v o l v e s s i m i l a r concepts: g a s i f i c a t i o n followed by product s y n t h e s i s . The chemistry o f the f i n a l product s y n t h e s i s steps are d i f f e r e n t f o r these two cases, r e s u l t i n g i n d i f f e r e n t gas c o n d i t i o n i n g steps between g a s i f i c a t i o n and product s y n t h e s i s . Table VII presents the estimated investments. The methanol case investment r e f l e c t s the same g a s i f i e r type as used f o r the IBG and SNG cases. A conceptual Chem Systems methanol s y n t h e s i s step i s used. EPRI i s sponsoring the development o f the Chem Systems technology(5_) . The ammonia case investment r e f l e c t s the same wood g a s i f i c a t i o n concepts, employs pressure swing a d s o r p t i o n f o r hydrogen gas p u r i f i c a t i o n (based on i n f o r m a t i o n p r o v i d e d by the Linde D i v i s i o n , Union Carbide C o r p o r a t i o n ) , and uses a convent i o n a l high-pressure ammonia s y n t h e s i s loop.


3.

KOHAN

39

Economics of Conversion Using Wood Feedstocks Table VI

LIQUID FUELS PRODUCTION


Principal

Product:

FROM WOOD - PRODUCT REVENUE

Fuel O i l ( C a t a l y t i c Liguef.)

REQUIREMENTS

Pyrolytic

Oil,Char

$/GJ

$/πΓ

$/GJ


1.73

68.6

1.29

Labor-Related

1.14

45.0

0.82

Purchased M a t e r i a l s

0.42

16.6

0.08

F i x e d Costs

0.60

23.9

0.17

0.76

29.8

0.21

1.37

5 3.8

0.41

6.02

237.7

(8.25)

(325.6)

Plant Depreciation

(20-yr)

2 Return on Rate Base & Income Tax 2 Total-Regulated

Utility

(Total-Nonregulated Financing)

2.98

Financing

(3.66)

Industrial

T o t a l Product B a s i s 2 20-Year Average Values Basis:

1.8 χ 10 kg/d green wood (50 wt.% moisture) f e e d r a t e

Table V I I

CHEMICALS PRODUCTION FROM WOOD - ESTIMATED INVESTMENT

P r i n c i p a l Product: Product

Methanol 12 11.6 χ 10 J/d

Rate:

Plant Financing:

Regulated Utility

Am 5 4.5 χ 10

Non-Regulated Industrial

Investment, M i l l i o n s o f D o l l a r s ( 1 9 7 7 ) Plant F a c i l i t i e s

Investment

88.0

95.5

Land

0.3

0.3


4.4

4.8

I n t e r e s t During

6.7

Construction


2.1

T o t a l C a p i t a l Investment Basis:

6

1.8 χ 1 0 kg/d green wood

kg/d

101.5

2.2 102.8

(50 wt.% moisture) f e e d r a t e




40

0

10

20 S E L L I N G PRICE OF C H A R

30 —

40

50

dollars per short ton

Figure 3. Production of oil and char by pyrolysis of wood—selling price of pyrolytic oil as a function of selling price of char (regulated utility financing)


3.

KOHAN


41


Table VIII presents the estimated revenue requirements. The methanol case uses r e g u l a t e d u t i l i t y f i n a n c i n g , and the ammonia case, non-regulated i n d u s t r i a l f i n a n c i n g , based on c o n s i d e r a t i o n s of the l i k e l y markets to be served by these products. The e s t i mated costs o f producing methanol o r ammonia from wood are h i g h e r than the costs o f producing methanol o r ammonia from c o a l . This i s e x p l a i n e d i n p a r t by p r o d u c t i o n r a t e s (the r a t e s from woodd e r i v e d methanol p l a n t s are about one-tenth o f those from " t y p i c a l " c o a l - d e r i v e d methanol p l a n t s ; ammonia p r o d u c t i o n rates are s i m i l a r from the two resources s i n c e the ammonia market i s t y p i c a l l y demand-constrained); and p a r t i a l l y by feedstock d i f f e r e n c e s (e.g., green wood i s h a l f m o i s t u r e ) .

Table VIII CHEMICALS PRODUCTION FROM WOOD - PRODUCT REVENUE REQUIREMENTS

P r i n c i p a l Product:

Methanol

Ammonia

$/GJ

$/mt


1.64

42.2

Labor-Related

1.28

35.2

Purchased

0.85

20.5

1.03

28.9

Materials

F i x e d Costs Plant Depreciation

(20-yr)

Return on Rate Base & Income T a x C a p i t a l Charges

1.30 1

f o r a 15% DCF Return

Total

—

203.9

-

8.39

20-Year Average 2 Non-Regulated

2.29

(12.13)

2

330.7 ι

Values

Industrial Financing

^Regulated U t i l i t y F i n a n c i n g Basis:

1.8 χ 1 0

6

kg/d green wood (50 wt.% moisture) f e e d

rate

Conclusions The p r i c e s o f wood-derived energy and chemicals products developed i n t h i s a n a l y s i s tend to be h i g h e r than corresponding p r i c e s o f c o a l - d e r i v e d products. This i s e x p l a i n e d i n p a r t by s m a l l e r p r o d u c t i o n r a t e s from wood f a c i l i t i e s than from c o a l f a c i l i t i e s , which i s i n t u r n a t t r i b u t e d to p e r c e p t i o n s o f the amount o f feedstocks a v a i l a b l e t o i n d i v i d u a l energy conversion p r o j e c t s ; i n p a r t t o feedstock d i f f e r e n c e s (e.g., green wood i s h a l f moisture); and other f a c t o r s . Wood i s a r e g i o n a l resource;


42


coal is not. Wood fuel for proposed u t i l i t y steam/electric plants may be obtained from forest c u l l wood and thinning operations. Thus forests are made more conducive to the production of commerc i a l timber, and a residue disposal problem is solved by generating e l e c t r i c i t y . As energy prices continue to escalate, increasing uses may be found for regional biomass resources.


Acknowledgments This work was performed at SRI International for the Department of Energy. The assistance of the DOE Technical Managers, Mr. Nello del Gobbo and Dr. Roscoe F. Ward, is gratefully acknowledged. Literature Cited 1.

2.

3.

4.

5.

Kohan, S.M., and Barkhordar, P.M., "Mission Analysis for the Federal Fuels from Biomass Program. Volume IV: Thermochemical Conversion of Biomass to Fuels and Chemicals," report prepared by SRI International for DOE under Contract EY-76-C-03-0115 PA131 (January, 1979) NTIS SAN-0115-T3 Jones, J . L . , Kohan, S.M., and Semrau, K . J . , "Mission Analysis for the Federal Fuels from Biomass Program. Volume VI: Mission Addendum," report prepared by SRI International for DOE under Contract EY-76-C-03-0115 PA131 (January, 1979). Kohan, S.M., and Dickenson, R . L . , "Production of Liquid Fuels and Chemicals by Thermal Conversion of Biomass Feedstocks," paper 78f to be presented at the 72nd AIChE Annual Meeting, San Francisco, CA, November 25-29, 1979. Jones, J . L . , "The Costs for Processing Municipal Refuse and Sludge," paper presented at the Fifth National Conference on Acceptable Sludge Disposal Techniques, Orlando, FL, January 31, 1978. Sherwin, M.B., and Blum, D . , "Liquid Phase Methanol," report prepared by Chem Systems, Inc., for the E l e c t r i c Power Research Institute, EPRI AF-202 (August, 1976).

RECEIVED November 16, 1979.


Thermal Conversion of Solid Wastes and Biomass - American

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