methane from wastes

8/12/2019 Methane From Wastes

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Potential Production of Methane fromCanadian Wastes

By

Salim Abboud, Kevin Aschim, Brennan Bagdan, Partha Sarkar, Hong i!uan, Brent Scorfield and Christian "elske, Alberta #esearch Council

Shahr$ad #ahbar and %ouis Marmen,Canadian &as Association


2/94

"inal #e'ort ( Se'tember )*+*

)

)


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TABLE OF CONTENTSPage

% S- ." -AB%/S 000000000000000000000000000000000000000000000000000000000000000000000000

% S- ." " &1#/S 00000000000000000000000000000000000000000000000000000000000000000000000

/2/C1- 3/ S1MMA#! 00000000000000000000000000000000000000000000000000000000000000000000

+0* 4-#.51C- .4 0000000000000000000000000000000000000000000000000000000000000000000+0+ .b6ective00000000000000000000000000000000000000000000000000000000000000000+0) A''roach000000000000000000000000000000000000000000000000000000000000000000

)0* B .&AS, S!4&AS A45 #/4/WAB%/ 4A-1#A% &ASP#.51C- .4 P#.C/SS/S "#.M WAS-/S00000000000000000000000000000000000000000 7)0+ Anaerobic 5igestion000000000000000000000000000000000000000000000000000000000

)0) &asification0000000000000000000000000000000000000000000000000000000000000000)07 .ther /nergy Production Processes from Wastes00000000000000000000000000000 :

)070+ "ermentation00000000000000000000000000000000000000000000000000000000)070) Combustion000000000000000000000000000000000000000000000000000000000)0707 Pyrolysis00000000000000000000000000000000000000000000000000000000000

70* M/-HA4/ P#.51C- .4 P#.C/SS/S "#.M B .&AS A45S!4&AS 00000000000000000000000000000000000000000000000000000000000000000000000070+ Cleanu' 000000000000000000000000000000000000000000000000000000000000000000

70+0+ Biogas Cleaning 000000000000000000000000000000000000000000000000000070+0) Bio Syngas Cleaning and -reatment 0000000000000000000000000000000000000

70) Se'aration 0000000000000000000000000000000000000000000000000000000000000000070)0+ %i uid Absor'tion 00000000000000000000000000000000000000000000000000070)0) Solid Physical Adsor'tion 000000000000000000000000000000000000000000000070)07 Membrane Se'aration 000000000000000000000000000000000000000000000000070)08 Cryogenic &as Se'aration 00000000000000000000000000000000000000000000070)09 Summary 0000000000000000000000000000000000000000000000000000000000

80* P#.51C- .4 ." B .&AS, S!4&AS A45 #/4/WAB%/ 4A-1#A%&AS "#.M CA4A5 A4 WAS-/S 0000000000000000000000000000000000000000000000000000080+ Agricultural Wastes 00000000000000000000000000000000000000000000000000000000

80+0+ Cro' #esidues 0000000000000000000000000000000000000000000000000000000

80+0) %ivestock Manure 00000000000000000000000000000000000000000000000000080) "orestry Wastes 000000000000000000000000000000000000000000000000000000000000807 Munici'al Wastes 00000000000000000000000000000000000000000000000000000000000

8070+ Munici'al Solid Waste 0000000000000000000000000000000000000000000000008070) Waste>ater 00000000000000000000000000000000000000000000000000000000080707 Biosolids 000000000000000000000000000000000000000000000000000000000080708 %andfills 000000000000000000000000000000000000000000000000000000000080709 -otal Munici'al Wastes 000000000000000000000000000000000000000000000000

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TABLE OF CONTENTS (CONCLUDED)Page

90* P#.51C- .4 ." M/-HA4/ "#.M CA4A5 A4 WAS-/S 00000000000000 :*

90+ -echnical "easibility 0000000000000000000000000000000000000000000000000000000090) /conomic "easibility 00000000000000000000000000000000000000000000000000000000

90)0+ /stimating the /conomically #ecoverable #esource 00000000000 ::90)0) Pi'eline versus Po>er 000000000000000000000000000000000000000000000000090)07 #isk Sensitivity and Mitigation Analysis 00000000000000000000000000000 :=90)08 Com'aring the "our Scenarios 000000000000000000000000000000000000000000

:0* //4H.1S/ &AS MPAC- ." M/-HA4/ CAP-1#/ "#.MCA4A5 A4 WAS-/S 00000000000000000000000000000000000000000000000000000000000000

;0* C.4C%1S .4S 0000000000000000000000000000000000000000000000000000000000000000000


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LIST OF TABLESPage

-able +0 Canadian )**; Cro' Production and /stimates of Cro' #esidues 000000000 ):

-able )0 4e>foundland and %abrador )**; Cro' Production and /stimatesof Cro' #esidues 000000000000000000000000000000000000000000000000000000000000000

-able 70 Prince /d>ard sland )**; Cro' Production and /stimates of Cro'#esidues 000000000000000000000000000000000000000000000000000000000000000000000

-able 80 4ova Scotia )**; Cro' Production and /stimates of Cro' #esidues 0000 );

-able 90 4e> Bruns>ick )**; Cro' Production and /stimates of Cro'#esidues 000000000000000000000000000000000000000000000000000000000000000000000

-able :0 ?uebec )**; Cro' Production and /stimates of Cro' #esidues 000000000000 )chart of the Synthetic #ene>able 4atural &as @S4& #4&Production from Biomass 0000000000000000000000000000000000000000000000000000000

"igure 90 Availability of Canadian Cro' #esidues for A5 and &asification 000000000 78"igure :0 Potential Production of #4& from Canadian Cro' #esidues 00000000000000000 78

"igure ;0 Availability of Canadian Manures for A5 and &asification 000000000000000000 7=

"igure


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LIST OF FIGURES (CONCLUDED)Page

"igure =0 Potential Production of #4& from Canadian "orestry Wastes 00000000000000 8)

"igure +*0 Canadian Munici'al Solid Waste 5is'osal @)**9 000000000000000000000000000000000 8:

"igure ++0 Availability of Canadian MSW for A5 and &asification as Com'aredto -otal 5is'osed MSW 0000000000000000000000000000000000000000000000000000000000

"igure +)0 Potential Production of #4& from Canadian Munici'al SolidWastes 0000000000000000000000000000000000000000000000000000000000000000000000

"igure +70 Potential Production of #4& from Canadian Waste>aters 00000000000000000000 9*

"igure +80 Potential Production of #4& from Canadian Biosolids 0000000000000000000000000 97

"igure +90 Potential Production of #4& from Canadian %andfills 00000000000000000000000000 9:

"igure +:0 Potential Production of #4& from Canadian Munici'al Wastes 00000000000 9s that the greatest 'otential for 'roducing #4& from cro' residues is

through gasification as it consumes most of the biomass >hile anaerobic digestion is

limited to about )*E of that biomass0

Manure 'roduction on Canadian farms varies according to the ty'e of animals and

the animal 'o'ulation numbers, but is amenable for 'roducing #4&0 5ata sho>s that the

'otential for 'roducing #4& from manure residues is slightly higher through gasification

than that for anaerobic digestion0

"orestry residues are made u' of forest o'eration residues and mountain 'ine

beetle @MPB residues0 "orest residue data sho>s that the 'otentially available residuesare to be found mostly in BC @77E , ?uebec @);E and .ntario @+;E 0 Potential

'roduction of #4& from these residues through gasification sho>s a similar 'attern as

the residue distribution0

Canadian munici'al >astes considered as 'otential sources for #4& 'roduction

included solid >astes collected from homes and businesses by munici'alities @MSW ,

landfill gas recovered from closed landfills @%"& , >aste>aters @WW collected through

munici'al se>er systems, and the munici'al biosolids >hich are the solid materials

collected @through settling of the >aste>aters0

5ata of the contributions of each munici'al >aste to the total munici'al 'otential

#4& 'roduction sho>s that the largest sources of 'otential #4& are from solid >astes

@MSW and %andfills0 -his is understandable considering the much larger solid

'roduction of >astes from the above t>o sources0 Anaerobic digestion contributes

slightly more #4& than gasification due to the 'roduction of %"&0 -otal 'otential #4&

'roduction sho>s a distribution similar to 'o'ulation si$e0

-his munici'al >aste source is significant for the large contribution of anaerobic

digestion to #4& 'roduction allo>ing for the use of established technologies >ith much

easier technology u'take and ada'tation0 Another attractive as'ect for using this >aste is

the lo>er cost of 'roduction due to the absence of >aste collection and trans'ortation

costs as they are usually incurred by the munici'alities0 -he most significant costs are

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those associated >ith gas cleaning and se'aration0 Challenges e ist in ada'ting

gasification to munici'al >astes as fe> gasification 'lants e ist and those usually use the

syngas only to 'roduce 'o>er0 Most thermal treatments of munici'al >astes, have u'

until no> tended to favour incineration0

All 'otential #4& that can be 'roduced from the total Canadian >astes revie>ed,

sho>s that a 'otential total of )80= Mt yr of #4& can be 'roduced0 "orestry seems to

have the 'otential to 'roduce +)0= Mt yr @9+E of total , follo>ed by er cost0

We com'ared the relative si$e of our 'otential #4& estimates to the current

natural gas use for the residential and commercial sectors0 -he 'otential Canadian

generation of )80= Mt yr of #4& corres'onds to an energy value of +08 -G yr or

7s that to lo>er the cost of #4&, then the technology costs for cleaning

the biogas needs to be reduced0 At the moment, there is very little data on the cost to

clean gas to a 'i'eline grade0 Ho>ever, the economic models >hich have been 'resented

evaluated different scenarios >hich included e am'les of #4& used to 'roduce 'i'eline

grade natural gas, or #4& used in 'o>er 'roduction0 -he economics underlines the need

to develo' biogas cleaning technologies that lo>er ca'ital costs by an order of magnitude

over the current state of the art0

-he 'roduction and ca'ture of #4& from Canadian >astes contributes to &H&

reduction through t>o 'rocessesD emission reduction and fuel substitution0 /mission

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reduction can be achieved through the ca'ture of the emitted methane from landfills and

the anaerobic digestion of animal manures0 "uel substitution a''lies to the use of #4&

to re'lace any natural gas 'roduced from fossil fuels0

-otal &H& reductions >ere estimated as +*; Mt C. ) e yr for Canada >ith the

largest amounts found for ?uebec, .ntario and BC0 "uel substitution seems to contribute

more &H& reductions than emission reduction e ce't for those 'rovinces >ith large

forestry >astes such as BC0 Almost 77E of the Canadian &H& reductions arise from

emission reduction, >hile the rest @:;E from fuel substitution0

-he 'otential #4& 'roduction from >astes can contribute a significant amount of

&H& reductions and thus carbon credits, >hich may alleviate the cost of #4& 'roduction

if factoring in the sale of the C. ) 'roduced and the value of its carbon credit0.n a going for>ard basis, there is a need to engage a''ro'riate stakeholders and

various levels of government to get a better handle on the useful 'otential of #4&

considering s'atial infrastructure and economic factors, initiate 'olicy develo'ment as

>ell as undertaking additional technical develo'ment that >ill 'rovide more o'erating

and cost data0

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+0 INTRODUCTION

-he use of biomass resources for energy 'roduction started early in human

history, and continued to be the ma6or source of energy until overtaken by coal then oil in

the +=th and )* th centuries0 Biomass su''lies 90=E of Canadian 'rimary energy sources,

+9E of the >orld s energy and 79E of the develo'ing countries needs @Holmes and

/d>ards, )**7 0 -he rest of the energy needs are su''lied by fossil fuels0 Concern about

the use of fossil fuels and the resulting atmos'heric buildu' of carbon dio ide has led to a

reevaluation of biomass resources for energy 'roduction0

-he ne> efforts to use biomass for energy 'roduction centre on increasing

efficiency, 'romoting sustainability of this resource and lo>ering carbon dio ide

atmos'heric levels by re'lacing fossil fuels0-his re'ort evaluates the role >astes can 'lay in 'roducing energy from >aste

biomass by generating methane from Canadian >astes, >hich can then be used a

rene>able natural gas @#4& source0 -his 'ath to energy 'roduction offers the

advantages of ne> 'reviously unta''ed sources of biomass and a solution to mounting

>aste 'roblems0

1.1. OBJECTIVE

-he ob6ective of this 'ro6ect is to conduct a literature based study >hose aim >ill

be to assess the technical 'otential for methane generation from Canadian >astes, and the

relative greenhouse gas @&H& im'acts of ca'turing the generated methane0 -he 'ro6ect

also looks at the economic viability of different scenarios involving the 'roduction of

#4&0 While the >ork does not attem't to uantify the useful 'otential of #4& in

Canada, >hich >ould need factoring in infrastructure and economic constraintsF the study

>ill enable the C&A to determine @>ith coarse granularity the resource base for methane

from >aste0

n 'articular the follo>ing sub(ob6ectives >ill be addressedD

-he sources of >astes that are or can be 'otentially converted into methane

@e0g0 Munici'al and Agricultural

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-he total resource 'otential nationally >ith 'rovincial breakdo>n >here

'ossible feasible @the technically feasible 'otential methane generation

/ 'ressed as 'ercent of domestic gas consum'tion or any other unit that

relates it to current gas use

-he economic viability of different scenarios involving the 'roduction of

#4&0

-he 'otential for &H& management @im'act of ca'turing methane, turning it

to C. ) and claiming the benefit 0

1.2. APPROACH

We revie>ed the literature >ith res'ect to the available 'rocesses for converting

>aste into rene>able natural gas @#4& and the results >ill be discussed in the follo>ing

cha'ters0 "urthermore, >e collected data related to the source and uantities of >astes

'roduced in Canada, organi$ed by 'rovince and for the >hole country0 We used the

>aste information to calculate 'otential uantities of #4& that can be 'roduced from

these >astes using assum'tions about the conversion 'ath>ays and yields0 -hese values

>ere based on the scientific literature and our o>n e 'erience and >ill be e 'lained later

in this re'ort0 -he 'otential #4& 'roduction values are discussed for each 'rovince andthe country in terms of #4& 'roduction 'ath>ays and their technical and economic

feasibilities0 Similar discussion is also included for the 'otential reduction in greenhouse

gases reali$ed from the 'roduction of #4& from >aste0

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)0 BIOGAS, SYNGAS AND RENEWABLE NATURAL GAS PRODUCTIONPROCESSES FROM WASTES

Biomass can be converted to fuel for 'roduction of energy, i0e0 electrical and

thermal or ra> materials for the synthesis of chemicals, li uid fuels, gaseous fuels such as

hydrogen and methane0 -here are five different technological routes by >hich energy

can be 'roduced from biomass0 -hese five 'rocesses are sho>n in "igure + and can be

grou'ed into thermochemical @biomass combustion, gasification and 'yrolysis and non(

thermal @anaerobic digestion and fermentation 'rocesses0 -hough the diagram in

"igure + has sho>n energy 'roduction but the chemicals 'roduced by digestion,

fermentation, gasification and 'yrolysis can be used as feedstocks for 'roducing other

useful chemicals0

Bi !"## C !$%#&i '(T *!"+ E' * -)

P-* +-#i#(+i.%i/ i+, "# %#0* /% "'/ C "*)

G"#i2i "&i '(G"# %# F% +)

F *! '&"&i '(A+ +#)

A'" * $iDi #&i '

(G"# %# F% +)

E' * -

Fi %* 1. Potential Path>ays for /nergy Production from Biomass0

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2.1. ANAEROBIC DIGESTION

Anaerobic digesters are commonly used for effluent and se>age treatment or for

managing animal >astes0 Anaerobic digestion is a sim'le 'rocess that can greatly reduce

the amount of organic matter >hich might other>ise end u' in landfills or >aste

incinerators 0 n develo'ing countries sim'le home and farm(based anaerobic digestion

systems offer the 'otential for chea', lo> cost energy from biogas0 /nvironmental

'ressure on solid >aste dis'osal methods in develo'ed countries has increased the

a''lication of anaerobic digestion as a 'rocess for reducing >aste volumes and

generating useful by'roducts0 Anaerobic digestion may either be used to 'rocess the

source se'arated fraction of biodegradable >aste, or alternatively combined >ith

mechanical sorting systems, to 'rocess mi ed munici'al >aste0 Almost any

biodegradable organic material can be 'rocessed >ith anaerobic digestion0 -his includes

biodegradable >aste materials such as >aste 'a'er, grass cli''ings, leftover food, se>age

and animal >aste0 Anaerobic digesters can also be fed >ith s'ecially gro>n energy cro's

or silage for dedicated biogas 'roduction0 After sorting or screening to remove 'hysical

contaminants, such as metals and 'lastics, from the feedstock the material is often

shredded, minced, or hydrocrushed to increase the surface area available to microbes in

the digesters and hence increase the s'eed of digestion0 -he material is then fed into anairtight digester >here the anaerobic treatment takes 'lace0 -here are four key biological

and chemical stages of anaerobic digestionD

+0 -he first is the chemical reaction of hydrolysis, >here com'le organic

molecules are broken do>n into sim'le sugars, amino acids, and fatty acids

>ith the addition of hydro yl grou's0

)0 -he second stage is the biological 'rocess of acidogenesis >here a further

breakdo>n by acidogens into sim'ler molecules, volatile fatty acids @3"As

occurs, 'roducing ammonia, carbon dio ide and hydrogen sulfide as

by'roducts0

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http://www.answers.com/topic/incineration-2http://www.answers.com/topic/incineration-2


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70 -he third stage is the biological 'rocess of acetogenesis >here the sim'le

molecules from acidogenesis are further digested by acetogens to 'roduce

carbon dio ide, hydrogen and mainly acetic acid0

80 -he fourth stage is the biological 'rocess of methanogenesis >here methane,

carbon dio ide and >ater are 'roduced by methanogens0

A sim'lified generic chemical e uation of the overall 'rocess is as follo>sD

C: H+) . : I 7C. ) J 7CH 8

2.2. GASIFICATION

&asification is a 'rocess that converts carbonaceous materials, such as coal,

'etroleum, or biomass, into carbon mono ide, hydrogen and methane by the reaction of

the ra> organic feedstock at elevated tem'eratures >ith a controlled amount of o ygen at

a deficit condition0 -he resulting gas mi ture is called synthesis gas or syngas and is itself

a fuel0 &asification is a very efficient method for e tracting energy from many different

ty'es of organic materials0 -he advantage of gasification is that using the syngas is more

efficient than direct combustion of the original ra> feedstockF more of the energy

contained in the ra> feedstock is e tracted0 Syngas may be burned directly in internal

combustion engines, used to 'roduce methanol and hydrogen, converted via the "ischer(

-ro'sch 'rocess into synthetic fuel, or converted to methane through catalytic

methanation0 &asification can also begin >ith materials that are not other>ise as useful

fuels, such as biomass or organic >aste0 n addition, the high(tem'erature combustion

refines out corrosive ash elements such as chloride and 'otassium, allo>ing clean gas

'roduction from other>ise 'roblematic fuels0 &asification of coal is currently >idely

used on industrial scales to generate electricity0 Ho>ever, almost any ty'e of organic

material can be used as the ra> material for gasification, such as >ood, biomass, or even 'lastic >aste0 -hus, gasification may be an im'ortant technology for rene>able energy0

&asification relies on chemical 'rocesses at elevated tem'eratures, ;** C(+hich

distinguishes it from biological 'rocesses such as anaerobic digestion that 'roduce

biogas0

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o ygen, and a source of heat0 As a result of combustion, e hausts are created and heat is

generated0 .ne can control or sto' the combustion 'rocess by controlling the amount of

the fuel available, the amount of o ygen available, or the source of heat0

2.3.3. P-* +-#i#

Pyrolysis is a chemical decom'osition induced in organic materials by thermal

energy in the absence of o ygen0 But in real >orld a''lication, it is not 'ossible to

achieve a com'letely o ygen(free atmos'here0 Pyrolysis transforms organic materials

into gaseous com'onents, li uid, and a solid residue @coke containing fi ed carbon and

ash0 Pyrolysis of organic materials 'roduces combustible gases, including carbon

mono ide, hydrogen and methane, and other hydrocarbons0 f the off(gases are cooled,li uids condense 'roducing an oil tar residue and contaminated >ater0 Pyrolysis ty'ically

occurs in the tem'eratures range bet>een 79* C(99* C0 n general it is a sim'le, lo>(

cost technology ca'able of 'rocessing a >ide variety of feedstocks 'roducing gases, a

bio(oil, bio(chemicals, and charcoal0 An ancient industrial use of anhydrous 'yrolysis is

the 'roduction of charcoal through the 'yrolysis of >ood0 n more recent times, 'yrolysis

has been used on a massive scale to turn coal into coke for metallurgy, es'ecially

steelmaking0

Slow pyrolysis is a thermochemical decom'osition of organic material at elevated

tem'eratures in the absence of o ygen0 -he feed material is dried and fed into a stirred,

heated kiln0 As the material 'asses through the kiln, a combustible gas is evolved and is

continuously removed from the reactor0 A''ro imately 79E by >eight of the dry feed

material is converted to a high(carbon char material that is collected on the discharge of

the reactor0 -y'ical yield is 7*E li uid @mostly >ater , 79E gaseous 'roduct and 79E

char0

Anhydrous 'yrolysis can also be used to 'roduce li uid fuel similar to diesel from solid

biomass0 -he most common techni ue uses very lo> residence times @ ) seconds and

high heating rates using a tem'erature bet>een 7** and 9** C and is called either fast

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H"+ ,)'"&)/H-/* 1"*$ ' R)! 4"+

C"*$ ' Di 5i/)R)! 4"+

R"6 Bi ,"#

Main m'urities to be removedDH) S Corrosion, -o icity, Sulfur . idesformation

H) . Condensation in gas lines, corrosive acidsolution formation

HC(2 CorrosionC. ) #educing energy content, &H&

A'")* $i1 Di,)#&i '

M i#&%*)R)! 4"+

P"*&i1%+"&)R)! 4"+

H-/* ,)' S%+2i/)R)! 4"+

Si+ 5"')R)! 4"+

#efrigeration, absor'tion @glycol , adsor'tion @silicagel , Cyclone se'arator or knockout dram

"iltration, cyclone se'arator, electrostatic 'reci'itation

AirBo ygen in6ection to digester, ron chloride mi ing todigester slurry, #eacting biogas >ith ron o ide or hydro ide, m'regnated Activated Carbon @PSA ,Water O 4a.H scrubbing

Activated carbon adsor'tion, Cryogenic condensation,Physical absor'tion by Polyethylene &lycol or Sele ol-M , Hydrocarbon .il

Activated carbon, or removed >ith C. )

C+ "' Bi ! & "'(RNG)

C+)"' C"*$ '

Di 5i/)

Fi %* 2. "lo>chart of the Biogas Cleaning Process0

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Particle Removal : Some moisture removing techni ues also remove 'articles as

>ell as some 'article removal techni ues also remove moisture0 "iltration is a sim'le

>ay to remove 'articles0 Gust 'assing the biogas through stainless steel mesh filter orfilter 'ad can remove 'articles as >ell as some of the moisture0 Cyclone se'arator can be

very effective to remove larger 'articles as >ell as some moisture from the biogas0 Here

centrifugal force is used for se'arating the 'articles from the biogas stream0 /lectrostatic

'reci'itator can be used to remove 'articles from biogas0

Hydrogen Sulfide Removal D Hydrogen sulfide is needed to be removed in order

to avoid corrosion in com'ressors, 'i'eline, gas storage tank and other metallic 'arts0 .n

the to' of its corrosiveness it is also to ic0 5ue to all these 'otential 'roblems >ith

hydrogen sulfide, it is generally removed at the early stages of cleaning 'rocess0 -here

are number of >ays hydrogen sulfide can be removed as listed belo>D

Air . ygen in6ection to digester biogas

ron chloride mi ing to digester slurry

ron o ide or iron hydro ide

m'regnated activated carbon Water scrubbing

Sodium hydro ide scrubbing

Air or o ygen in6ection is a biological method of removing of hydrogen sulfide0

. ygen 'romotes sul'hur o idi$ing bacteria in the digester and the bacteria converts

hydrogen sulfide to yello> cluster of sul'hur0 -hough air in6ection is sim'le and a lo>

cost solution, it introduces nitrogen in the biogas >hich is difficult to remove0

ron chloride in digester slurry reacts >ith hydrogen sulfide and forms iron

sulfide0 -his method is very effective in reducing high hydrogen sulfide levels but less

effective in attaining lo> and stable levels0 ron o ide or iron hydro ide can be used for

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removal of hydrogen sulfide, here iron o ide hydro ide react >ith hydrogen sulfide of

the biogas and form iron sulfide0 n this case biogas is 'assed through iron

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o ide hydro ide bed0 -his reaction is slightly endothermic, o'timum reaction

tem'erature is bet>een )9 C and 9* C0 ron o ide can be recovered by reacting iron

sulfide >ith air0 -his regenerative 'rocess is highly e othermic0

With 'ressure s>ing adsor'tion @PSA systems hydrogen sulfide is removed by

'otassium iodide im'regnated activated carbon0 "or this 'rocess small amount of air is

needed to be added in the biogas0 Hydrogen sulfide is catalytically converted to sul'hur

and >ater0 -his reaction occurs at a 'ressure of ; to < bar and a tem'erature of 9* C(

;* C0 -he sul'hur is adsorbed by activated carbon0

Hydrogen sulfide is soluble in >aterF therefore, >ater scrubbing can be used toremove hydrogen sulfide0 Contaminated >ater must be regenerated before reuse0

Hydrogen sulfide can be desorbed from >ater and the result is a fugitive emission0 Water

solution of sodium hydro ide has higher hydrogen sulfide absor'tion ca'acity than 'ure

>ater0 Sodium hydro ide reacts >ith hydrogen sulfite and form sodium sulfide0 Ma6or

'roblem here is the dis'osal of sodium sulfide contaminated >ater0

Halogenated Hydrocarbon Removal: Halogenated hydrocarbon including

hydrochloric acid, hydrofluoric acid and chlorinated aromatics are difficult to remove in

lo> concentration0 &enerally halogenated hydrocarbons are simultaneously removed

>ith carbon dio ide0 Activated carbon can be used for removing halogenated

hydrocarbon0

Siloxane Removal: Silo ane form siliceous de'osit on engine and enhances the

>ear and as a result reduces the lifes'an of the engine or engine 'arts0 t can be removed

by several >ays0 Activated carbon can remove silo ane by adsor'tion0 Cryogenic

condensation can be used for removing it0 t is 'ossible to remove ==E of silo ane by

cooling the biogas at (;* C0 Polyethylene glycol or Sele ol -M , a commercially available

solvent can be used for silo ane removal0 Here 'hysical absor'tion is the mechanism0

-his chemicals are not selective to silo ane removal, it also remove carbon dio ide,

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hydrogen sulfide and >ater va'or0 Hydrocarbon oil can be effective in removing

silo ane and the oil can be regenerated by vacuum treatment0

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#a> biogas is normally saturated >ith moisture and it must be removed to avoid

corrosion of 'i'ing and the e ui'ments and free$ing 'roblems in >inter0 Moisture should

be removed close to the do>nstream 'rocess unit0 Multi'le moisture ta's can be installedin the vital location of the 'i'ing net>ork0 -here are multi'le >ays to remove moisture,

such as refrigeration, here biogas is cooled belo> its de> 'oint to condense >ater and

remove it0 t can be removed using absor'tion techni ue such glycol or some salt

absorbed moisture0 Absorbing chemical can be regenerated by drying at high

tem'erature0

3.1.2. Bi S-' "# C+ "'i' "'/ T* "&! '&

A biomass gasification system can be divided into four ma6or ste's, as sho>n in

the 'rocess flo>chart they are ra> biomass conditioning, gasification, crude biosyngas

cleaning and gas utili$ation0 5e'ending on the biomass feedstock and the ty'e of

gasifier, the ra> biomass must be conditioned @si$ed, dried etc0 0 Achieving a good

continuous and reliable biomass conditioning is often one of the most im'ortant 'oints in

o'eration of a gasification 'lant0

Fi %* 3. "lo>chart of the "our Main Ste's in a Biomass &asification System0

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-here are several different ty'es gasifier technologies available, each of them has there

o>n characteristicsD

"luidi$ed bed gasifiers

"i ed bed gasifiers

/ntrained flo> gasifiers

ndirect gasifiers

f gasification is 'erformed at high tem'erature @e0g0, entrained flo> gasification

i0e0, +)** C, biomass is com'letely converted into H ) , C., C. ) O H ) .0 -his biosyngas

is free from tar and is chemically similar to syngas derived from fossil fuels and can be

used for the same a''lications such as "isher -ro'sch diesel 'roduction, Methanol 5M/

'roduction, Ammonia 'roduction, Hydrogen source etc0 -he advantages of entrained

flo> gasification are that there is a lot of e 'erience >ith large scale 'lants using coal O

refinery >aste0 "eeding Qra>R biomass into such a 'lant is often not 'ossible and the lo>

energy density of biomass favors smaller scale 'lants for >hich this entrained flo>

gasifier is not suitable0

%o> tem'erature gasification @fluidi$ed bed, fi ed bed gasifier , i0e0, +*** C is

the other o'tion and commonly used for biomass gasification0 -he uality and 'urenessof the biosyngas al>ays differ bet>een different gasifiers0 m'urities in a ra> syngas are

tar, 'articulates, halogens, alkali metals, S(com'ounds, 4(com'ounds, heavy metals,

calcium etc0 -y'ically most all the cleaning 'rocesses o'erates at lot lo>er tem'erature

that the gasifier itself0 -herefore, ra> syngas need to be cooled for cleaning treatment0

n most cases, it is desirable to utili$e the sensible heat in the gas, for e am'le raising

steam0

n some cases first ste' in this 'rocess is a >ater scrubber that utili$es >ater trays

to >ash and cool the syngas0 -he >ater scrubber removes the fine solids, as >ell as

ammonia, chlorides, and other trace com'onents that are >ater soluble0 -he acid gas

removal @A system is designed to remove greater than ==E of the total sulfur from

the ra> syngas0 Primary sulfur com'ounds in the syngas are hydrogen sulfide @H ) S and

carbonyl sulfide @C.S 0 Because C.S is not readily ca'tured by the A, a hydrolysis

+9


27/94

unit is utili$ed u'stream of the A to react C.S >ith >ater va'or in the 'resence of a

catalyst to form H ) S and C. ) 0

Solids 'articulates can be removed by cyclone se'arators, barrier filters,

electrostatic filters, and >et scrubbers0 Cyclone se'arators are a 'rimary means of

removing bulk 'articulates from gas streams0 -hey rely on centrifugal force to se'arate

solids from the gas by directing the gas flo> into a circular 'ath0 Cyclone se'arators are

em'loyed as an initial gas cleanu' ste' in most gasifier systems because they are

effective and relatively ine 'ensive to o'erate0 Cyclone se'arators are effective at

removing larger 'articles and can o'erate over a >ide range of tem'eratures, limited

'rimarily by the material of construction0 -hey can remove =*E of 'articulates above

about 9 microns in diameter at minimal 'ressure dro's of *0*+ atm0 Since cyclonese'arators can o'erate at elevated tem'eratures, the sensible heat in the 'roduct gas can

be retained0 Cyclone se'arators also remove condensed tars and alkali material from the

gas streamF although the va'ori$ed forms of those constituents remain in the gas stream0

Barrier filters include a range of inorganic 'orous membranes that allo> gases to

'enetrate but 'revent the 'assage of 'articulates0 Barrier filters membranes can be

designed to remove almost any si$e of 'articulate, including those in the sub(micron

range, but the 'ressure differential across the filter >ill increase as the 'ore si$e

decreases0 As a result, there are technical and economic constraints that effectively limit

'articulate removal to about *09 m in systems such as gasifiers that must handle large

gas volumes0 "ilters are cleaned by 'eriodically 'assing 'ulsing clean gas through the

filter in the reverse direction of normal gas flo>0 -o reduce the overall 'articulate load,

these filters are ty'ically 'laced do>nstream from cyclone se'arator0 /lectrostatic filters

have also been used e tensively in a variety of gas cleaning o'erations0 n these systems,

the 'roduct gas flo>s 'ast high(voltage electrodes that im'art an electric charge to

'articulates, but do not affect the 'ermanent gases0 -he 'articulates are then collected as

the gas stream 'asses collector 'lates of the o''osite 'olarity0 -he electrically charged

'articulates migrate to the collector 'late and de'osit on the surface0 Particulates are

removed from the scrubber 'lates by either >et or dry methods0 5ry scrubbers use

+:


28/94

mechanical action to 'eriodically remove material from the surface and can o'erate at

tem'eratures of 9** C or more0

-he 'resence of tars in the 'roduct gas is seen as the biggest 'roblem in the

smooth a''lication of biomass 'roduct gas as source of sustainable energy0 -ar is formed

in the gasifier and com'rises a >ide s'ectrum of organic com'ounds, generally

consisting of several aromatic rings0 Heavy tars condense out as the gas tem'erature

dro's and cause ma6or fouling0 -he tar de> 'oint is a critical factor0 %ight tars like

'henol or na'hthalene have limited influence on the tar de> 'oint, but are not less

'roblematic0 %ight tars like 'henol chemically 'ollute the bleed >ater of do>nstream

condensers and a ueous scrubbers0 4a'hthalene is im'ortant as it is kno>n to crystalli$e

at the inlet of gas engines causing a high service demand0 -ar can be removed fe>different >ays as follo>sD

Thermal tar cracking: A thermal tar cracker heats u' the 'roduct gas to a

tem'erature of +)** C0 At this tem'erature the tars are removed almost com'letely

leading to a very lo> tar concentration @ +** mg m 7 and tar de> 'oint @ +* C 0

-hermal cracking take 'lace in the gasifier >hich o'erates +)** C, such as entrained(

flo> slagging gasifiers0 t is not 'ractical to set u' thermal cracking outside the gasifier0

Catalytic tar cracking: A catalytic tar cracker does not heat u' the 'roduct gas

and thus eliminates the disadvantages of a thermal cracker0 -here are a large number of

different catalysts that have been used to eliminate the tars in the 'roduct gas from the

gasification 'rocess0 -he t>o most researched grou's are 4i(based catalysts and

dolomites0 When 4i(based catalysts are used, tar concentration in the 'roduct gas can be

reduced significantly by means of reforming but since this 'rocess is endothermic, a 'art

of the chemically bound energy of the gas has to be burned to sustain this 'rocess0 -his

effect leads to a decreased efficiency of the gasification 'rocess0 n contrast, >hen so

called tar cracking catalysts such as dolomite are used, the only thing that is reformed is

the tar itself >hile lo> hydrocarbons e0g0 methane, ethane and 'ro'ane are left intact0 -ar

cracking can be defined as a 'rocess that breaks do>n the larger, heavier and more

com'le hydrocarbon molecules of tar into sim'ler and lighter molecules by the action of

+;


29/94

heat and aided by the 'resence of a catalyst but >ithout the addition of hydrogen0 ->o

>ell kno>n tar cracking catalysts are naturally occurring mineralsD dolomite and olivine0

Tar removal by a ueous scrubbers: A ueous tar removal systems cool do>n the

'roduct gas and remove the tars by condensation0 n most a ueous systems dust and tars

are collected simultaneously0 -he 'roduct gas is cooled do>n and aerosols of dust and

tars are collected0 -o avoid tar condensation and fouling of 'i'ing the gas should not

cool do>n0 n the a ueous scrubber system a tar >ater 'roblem is created0 Mi ing

@heavy tars >ith >ater >ill lead to o'erational difficulties in the scrubber and huge

maintenance costs0 -he most im'ortant disadvantage is formed by >aste >ater handling0

Waste >ater handling is often so e 'ensive that the 'lants economical feasibility is at

stake0/C4 and 5ahlman "ilter -echnology develo'ed the oil based tar removal system

.%&A0 n .%&A the tars are removed by condensation and by absor'tion0 -he

tem'erature remains above the >ater de> 'oint to avoid mi ing of dust and tar >ith

>ater0 5ue to the absor'tion ste' in .%&A the tar de> 'oint is decreased far belo> the

o'erating tem'erature of .%&A, ty'ically belo> +* C0 -he total tar concentration is

reduced to )** mg m 70 -ars do>nstream @.%&A 'rocess are com'osed of light

com'ounds like 2ylene and ndene0 -hese com'ounds do not cause fouling 'roblems in

the do>nstream system0 Phenols are almost com'letely removed in .%&A to avoid the

'roduction of ha$ardous condense >ater and e 'ensive >aste>ater cleaning0

#a> bio('roduct gas or biosyngas can be converted to methane rene>able natural

gas0 /C4 is e tensively >orking in this area0 -he flo>chart of the 'rocess of making

rene>able methane from biomass via gasification is given in "igure 80 After ra> 'roduct

gas cleaning a catalytic methanation ste' is included to convert hydrogen and carbon

mono ide to methane0 -he last ste' of gas u'grading involves the removal of >ater, C. )

to meet the natural gas s'ecifications0 t also might include com'ression0 Bios yngas

cleaning treatment information are available from /C4 @ van #ee, )**7 and /C4 and the

book on &asification by @Higman and van der Burg, )**7 is an e cellent basic book on

this sub6ect0

+


30/94

Fi %* 7. Process "lo>chart of the Synthetic #ene>able 4atural &as @S4& #4&Production from Biomass0

3.2. SEPARATION

Se'aration technologies can be considered to belong to one of these four

categories @Kohl and #iesenfeld, +=ing and tem'erature s>ing adsor'tion

Membrane se'aration

Cryogenic se'aration0

+=


31/94

3.2.1. Li %i/ A$# *0&i '

%i uid absor'tion is a method commonly used to remove or se'arate gas

com'onents by a chemical solvent >hich selectively reacts or 'hysically bonds >ith

some gas com'onents0 By dissolving the reacted gas com'onents in the li uid 'hase and

the un(reacted gas com'onents remaining in the gas 'hase, the gas stream can be

se'arated efficiently0

-he main advantages of li uid absor'tion 'rocesses areD

Availability of many different solvents for re uired gas stream se'arations,

including alkanolamines, alkaline salt solutions and many other tailor(made

solvents for different gas se'arations0 &as se'aration efficiency is high0 By selecting a suitable absorbing li uid and

gas se'aration columnF the gas se'aration efficiency can be as high as ==0=E0

-he most common li uid absor'tion 'rocess is using alkanolamine solvents to

remove C. ) and H ) S from natural gas0 -he C. ) and H ) S level in the final gas

'roduced must meet the regulatory and industry re uirements0 -y'ically the

H ) S level is less then 8 ''m and C. ) level is less then )E @v v 0

-he 'rocess relies on conventional 'ack columns to 'rovide the gas li uid surfacecontact area0 -he solvent regeneration cycle consumes large amounts of energy0

-herefore the high ca'ital and o'erational costs become its disadvantage >hen com'ared

>ith other gas se'aration technologies0 -his 'rocess is more economically suitable to

large scale gas se'aration and 'urification @Mimura et al0, )**+F dem et al0, )**+F

#ochelle at al0, )**)F and Mari$, +==< 0

Although the li uid absor'tion 'rocess is the most mature technology for gas

se'aration, the ongoing research and develo'ments includesD

m'roving the solvent formulation to boost reaction kinetics and reduce

regeneration energy0

Column 'ack to 'rovide bigger surface to im'rove the mass transfer and reduce

o'erational related 'roblems such as flooding, channeling0

m'roving the 'rocess control0

)*


32/94

3.2.2 S +i/ P -#i "+ A/# *0&i '

-he solid 'hysical adsor'tion is based on the conce't of using micro('orous

materials as sorbents for gas 'urification and se'aration0 Most commonly used materials

are activated carbon, synthetic and natural $eolites, silica gel and activated alumina

@!ang, += adsorbents

and im'roved 'rocess configurations @Kohl and #iesenfeld, +=


33/94

based on a difference in the rate of 'ermeation rather than on an absolute barrier to one

com'onent, the se'arated com'onent that flo>s through the membrane @the 'ermeate is

never +**E 'ure0 Also, since a finite 'artial 'ressure differential is re uired as the

driving force, some 'ortion of the 'ermeating com'onent remains in the residue gas, and

+**E recovery is not 'ossible0 As these generali$ations >ould suggest, the 'rocess is

'articularly suitable for bulk removal o'erations rather than for the removal of trace

im'urities from gas streams0 t is 'ossible to reach high 'urity recovery gas >ith the hel'

of membrane module configurations and or combined >ith other technology, such as

li uid absor'tion 'rocess @Mulder, +==:F /cht, )**)F and Srikanth 0

-he membrane based 'rocesses for gas se'aration com'etes >ith technology

alternatives such as adsor'tion, cryogenic and li uid absor'tion 'rocesses in nichea''lication areas0 Membrane gas se'aration technology has its o>n advantages that

make it attractive to many industries and some large gas su''ly com'anies as >ell0

Based on the conce't of membrane gas se'aration the follo>ing four key factors can

influence the membrane se'aration 'erformanceD

membrane selectivity to>ards the gases se'arated

membrane flu or 'ermeability

the life of the membrane maintenance and re'lacement costs

-he membrane gas se'aration 'rocess has been used for hydrogen se'aration and

recovery, ammonia 'urge gas se'aration, refinery hydrogen recovery, syngas se'aration

in 'etro(chemical industry, C. ) enhanced oil recovery and natural gas 'rocessing0

A commercial 'rocess for C. ) removal from natural gas stream uses a combination of

membrane and li uid absor'tion 'rocesses0 -he membrane 'rocess is used to remove bulk C. ) to reduce the C. ) level in the gas stream, >hile the li uid 'rocess is used after

the membrane 'rocess to further remove C. ) to the re uired level0 4A-C. &rou'

started initial a''lication of this system in +=o membrane 'rocess 'lants

of 9* mmscfd and )9 mmscfd ca'acities to remove a bottleneck in the Benfield 'rocess, a

conventional li uid absor'tion 'rocess0 -he 'lants >ere designed to reduce the C. )

))


34/94

content in the 'roduced gas from a range of 89E to :9E do>n to about 7*E0 -his >as

sufficient to kee' the Benfield 'lant >ithin its 'rocess limitations0 Change in field

'roduction and develo'ment in membrane technology have changed the 'lant

considerably0 By the year )**:, membranes have re'laced the Benfield 'rocess and the

'lant is currently 'rocessing u' to +ell belo> other C. ) removal technologies @Parro, +=


35/94

-he main disadvantages areD

A clean feed is re uired0 Particulates and entrained li uids must be removed0

"iltration to remove 'articles do>n to one micron in si$e is 'referred0

Because membrane uses 'ressure as the driving force of the 'rocess, there

may be a considerable energy re uirement for gas com'ression0

1sing the mechanism of 'olymeric membrane 'ermeation to the se'aration of

gases started as early as +ever, the selectivity and 'roduction rates of the membranes available at the time

>ere 'oor, and the need for the re uired large membrane areas made membrane

'ermeation economically unattractive0 m'rovements in manufacturing methods have

resulted in im'roved membrane 'erformance and economics0 -he develo'mental and

commercial successes of the early +=


36/94

'ost combustion flue gases, landfill gas and biogas generated from anaerobic

digesters0

ncrease in the membrane o'eration tem'erature >ould allo> for the

se'aration of high tem'erature gas streams >ithout a significant tem'erature

dro' or heat loss0 -he develo'ment of inorganic based ceramic and carbon

fiber membranes might be germane for these ty'es of a''lications0

ncrease in the membrane selectivity >ould increase the se'aration efficiency0

Many research grou's are active in the areas of selecting and develo'ing

different ty'e of membrane materials and in im'roving the 'hysical and

chemical 'ro'erties of the membranes0

3.2.7 C*- 'i G"# S 0"*"&i '

Cryogenic se'aration involves cooling the gases to very lo> tem'eratures so that

some gas com'onents can be li uefied and thus se'arated from the gas 'hase0 -he most

'o'ular a''lications that are using this technology are in the 'roduction of li uid o ygen

and li uid nitrogen0 -he technology re uires a large 'lant to cool air to several hundred

degrees belo> $ero in order to se'arate the com'onent gases0 4itrogen and o ygen are

then distributed to customers in li uid form using tanker trucks0 Com'ared >ith otherse'aration technologies, cryogenic se'aration tend to use more energy unless the

concentration of easy li uefied gases are much higher >hich avoids cooling large

amounts of un(li uefied gas com'onents0 -his method is >orth considering >here there

is a high concentration of C. ) gas streams0 -he advantage is that it 'roduces a li uid

C. ) ready for trans'ortation by 'i'eline0 -he disadvantage is that it re uires high energy

in'uts to reach cryogenic tem'eratures0 Cryogenics are normally used for high 'ressure

gases such as 're(combustion decarboni$ation 'rocesses @Wong et al0, )**) 0

3.2.8 S%!!"*-

-he above stated four main technologies for gas se'aration and 'urification are all

actively used by many different industries0 -hey all have their o>n advantages and

disadvantages0 Sometimes a combination of these technologies can be used, for e am'le,

)9


37/94

a membrane 'rocess and a li uid absor'tion 'rocess can be used together to economically

remove C. ) from natural gas stream0 Ho> to select a suitable technology for each gas

stream is de'endent on the com'osition of the gas stream, the tem'erature and 'ressure

of the gas stream, the se'aration and 'urification re uirements, and most im'ortantly the

economic viability based on the ca'ital and o'erating costs and other market related

factors0

Among these technologies, the membrane technology is relatively ne> and there

is great 'otential for research and develo'ment in terms of membrane materials and

im'rovement of membrane fabrication and membrane module design0 "or 'ressure(

s>ing adsor'tion technology, the develo'ment of the ne> adsorbent material >ould also

have high 'otential to become a great candidate for the demanding gas se'aration and 'urification market0

):


38/94

80 PRODUCTION OF BIOGAS, SYNGAS AND RENEWABLE NATURAL GAS

FROM CANADIAN WASTES

Canadian >astes that are amenable to 'roducing #4& are those containing

significant amounts of biomass and are mostly generated by the agricultural, forestry and

munici'al sectors0

7.1. AGRICULTURAL WASTES

Agricultural >astes containing significant biomass are mostly made u' of cro'

residues and animal manures0 -hese >astes can be converted to biogas and syngas

through anaerobic digestion and gasification0 -he 'roduced biogas can be cleaned u' of

'otential contaminants and se'arated into CH 8 and C. ) both of >hich can be sold as#4& and industrial grade C. ) 0 Syngas can be cleaned u', methanated and then

se'arated into CH 8 and C. ) 0

7.1.1. C* 0 R #i/% #

Canadian cro' residues amenable for 'roducing #4& vary bet>een 'rovinces and

regions and are made u' of the unused 'art of the cro's0 We estimated cro' 'roduction

@e0g0 grain for the ma6or cro's gro>n in Canada using Statistics Canada data @Statistics

Canada, )**;a for each 'rovince and for the >hole country @-ables + to ++ 0 5ry matter

content of the re'orted cro's >ere estimated from assumed >ater contents as

recommended by #alevic and %ay$ell @)**: and re'orted in -ables + to ++0 -he unused

'arts of the 'lants >ere estimated from the harvest inde for each cro' @#alevic and

%ay$ell, )**: and the amount of removable residues >as assumed to be 9*E of the

unused biomass @-ables + to ++ 0 -he harvest inde is defined as the ratio of cro'

'roduction over the total biomass @cro' 'roduction and unused 'art of the 'lant 0

);


39/94

T"$+ 1. C"'"/i"' 299: C* 0 P* /% &i ' "'/ E#&i!"& # C* 0 R #i/% #

C* 0

A* " 1 C* 0P* /% &i ' 1

W"& *C '& '&2

D*- M"&& *P* /% &i ' 3

H"*4 #&I'/ 5 7

T &"+R #i/% 8

R ! 4"$+R #i/% ;

(1999 ") (


40/94

T"$+ 3. P*i' E/6"*/ I#+"'/ 299: C* 0 P* /% &i ' "'/ E#&i!"& # C* 0 R #i/% #

C* 0

A* " 1 C* 0P* /% &i ' 1

W"& *C '& '&2

D*- M"&& *P* /% &i ' 3

H"*4 #&I'/ 5 7

T &"+R #i/% 8

R ! 4"$+R #i/% ;

(1999 ") (


41/94

T"$+ 8. N 6 B*%'#6i < 299: C* 0 P* /% &i ' "'/ E#&i!"& # C* 0 R #i/% #

C* 0

A* " 1 C* 0P* /% &i ' 1

W"& *C '& '&2

D*- M"&& *P* /% &i ' 3

H"*4 #&I'/ 5 7

T &"+R #i/% 8

R ! 4"$+R #i/% ;

(1999 ") (


42/94

T"$+ :. O'&"*i 299: C* 0 P* /% &i ' "'/ E#&i!"& # C* 0 R #i/% #

C* 0

A* " 1 C* 0P* /% &i ' 1

W"& *C '& '&2

D*- M"&& *P* /% &i ' 3

H"*4 #&I'/ 5 7

T &"+R #i/% 8

R ! 4"$+R #i/% ;

(1999 ") (


43/94

T"$+ ?. S"#:9.?> ;738.7?

7)


44/94

T"$+ 11. B*i&i# C +%!$i" 299: C* 0 P* /% &i ' "'/ E#&i!"& # C* 0 R #i/% #

C* 0

A* " 1 C* 0P* /% &i ' 1

W"& *C '& '&2

D*- M"&& *P* /% &i ' 3

H"*4 #&I'/ 5 7

T &"+R #i/% 8

R ! 4"$+R #i/% ;

(1999 ") (.1; 11?.9>1 Statistics Canada0 )**;a0 "ield cro' re'orting series0 Catalogue no0 ))(**)(2 /, 3ol0 ater content7 Assumed values @#alevic and %ay$ell, )**: 0 -his is the ratio of 'roduction @e0g0 grain over total biomass8 Calculated as @5M 'roduction harvest inde (5M 'roduction; Assumes 9*E of total residue can be removed as a bioenergy feedstock @#alevic and %ay$ell, )**:

-he total Canadian residues for each cro' available for anaerobic digestion and

gasification are sho>n in "igure 90 -he data sho>s that the largest available cro'

residues are those from >heat @78E follo>ed by grain corn @+=E , barley @+n in -able +)0 -he data

sho>s the 'otential 'roduction of methane from biogas through anaerobic digestion @A5

and from syngas through gasification of the residues not consumed in the A5 'rocess0

Biogas generation from the cro' residues assumes that only )*E of the material is

amenable to digestion and that 7** Mm 7 CH 8 dry Mt of residues is 'roduced @Wiese and

Ku6a>ski, )**; 0 &asification of the cro' residues assumes a 'rocess conversion

77


45/94

efficiency of :9E according to the follo>ing reaction >here ) moles of carbon are

re uired to 'roduce + mole of CH 8 and + mole of C. ) D

)C J)H ) . T CH 8 J C. )

-he combined gasification and methanation 'rocesses re uired to convert

biomass to methane are re'orted to have efficiencies that vary from :8 to ;=E

@Mo$affarian et al, )**9 and U>art and #abou, )**: 0 We chose to use an efficiency of

:9E as a conservative value0

-he data sho>s that the greatest 'otential for 'roducing #4& from cro' residues

is through gasification @"igure : and -able +) as it consumes most of the biomass >hile

anaerobic digestion is limited to about )*E of that biomass0 -he largest amounts of

'otentially available cro' residues and 'otential #4& 'roduced are in the PrairieProvinces, in 'articular, Saskatche>an and Alberta @"igure : due to the large 'roduction

of >heat, barley and canola0 Smaller amounts are 'otentially available in .ntario and

?uebec due to significant 'roduction of grain corn0 -otal Canadian 'otential #4&

'roduction from cro' residues is estimated to be +0*9 M- CH 8 yr from anaerobic

digestion and 80=* M- CH 8 yr from gasification for a combined total of almost : M-

CH 8 yr0 Although this 'otential total 'roduction of #4& is technically feasible, one

needs to take into account the economic factors of this 'roduction, in 'articular the costs

of collection and trans'ortation of the residues to the 'lant@s and the market 'rice of

natural gas derived from fossil fuel sources0

78


46/94

T"$+ 12. P & '&i"+ M & "' P* /% &i ' * ! C"'"/i"' C* 0 R #i/% #.

R ! 4"$+R #i/% 1

M & "'AD 2 G"#i i "&i ' 3 T &"+7

(


47/94

Available Canadian Crop Residues

Wheat34%

Oats8%

Barley18%

Grain Corn19%

Mi ed Grains!%

Canola14%

"oybeans4%

Wheat

Oats

Barley

Grain Corn

Mixed Grains

Canola

Soybeans

Flaxseed

Rye

Tame HayFodder Corn

Fi %* 8. Availability of Canadian Cro' #esidues for A5 and &asification

!

1

#

3

4

$

&' () &" &B *C O& MB "+ AB BC &, &- .+Canada

M , C /

4 0 . r

(rovin e

(otential (rodu tion o2 R&G 2ro Canadian Crop Residues

A

Gas

Fi %* ;. Potential Production of #4& from Canadian Cro' #esidues

7:


48/94

7.1.2. Li4 #& < M"'%*

Manure 'roduction on Canadian farms varies according to the ty'e of animals and

the animal 'o'ulation numbers0 -hese manures are amenable for 'roducing #4& and

tend to vary bet>een 'rovinces and regions0 We estimated manure 'roduction for the

ma6or animal 'o'ulations according to Statistics Canada data for cattle @Statistics Canada,

)**;b , hogs @Statistics Canada, )**;c , shee' @Statistics Canada, )**< and 'oultry

@Statistics Canada, )**;d for each 'rovince and for the >hole country @-ables +7 to +9 0

Manure 'roduction >as calculated using statistics Canada animal 'o'ulation numbers

and a s'ecific average daily manure 'roduction rate for each animal as suggested by

Klass @+==< 0 -he average manure 'roduction rates @kg dry head day varied >ith the

animal ty'e from a high of 80:8 for cattle to *0*+*+ for turkeys @-ables +7 to +9 0 -hemanures available for #4& 'roduction are less than >hat is 'roduced as some of the

manures are already used for other 'ur'oses0 We estimated that the availability of cattle

manure >as )9E of the total cattle manure 'roduced >ith different availability indices

for hogs @n in -able +: and "igure ;0 -he data sho>s

that the largest available manure residues are those from cattle @8ed by

chicken @78E and hogs @+ith less than +E from turkey and shee' manures0 -he

cattle, chicken and hog manures make u' almost +**E of the available Canadian total0

Conversion of available manure residues to methane is sho>n in -able +: and

"igure s the 'otential 'roduction of methane from biogas through

anaerobic digestion @A5 and from syngas through gasification of the manures not

consumed in the A5 'rocess0 Biogas generation from the manures assumes that

)9* Mm 7 CH 8 dry Mt of manure is 'roduced @/lectriga$, )**; 0 &asification of the

manure residues assumes a 'rocess similar to that for cro' residues at a conversion

efficiency of :9E and a manure carbon content of 8*E @Klass, +==< 0

7;


49/94

-he data sho>s that the 'otential for 'roducing #4& from manure residues is

slightly higher through gasification @"igure < and -able +: than that for A50 -he largest

amounts of 'otentially available manures and 'otential #4& 'roduced are in the .ntario

and ?uebec @large hog and chicken numbers and the Prairie Provinces @large cattle

numbers , in 'articular, Alberta @"igure < 0 Smaller amounts are 'otentially available in

BC due to significant chicken 'o'ulation numbers0 -otal Canadian 'otential #4&

'roduction from manure residues is estimated to be +0+= M- CH 8 yr from anaerobic

digestion and +0:= M- CH 8 yr from gasification for a combined total of )0


50/94

T"$+ 13. C"'"/i"' P* /% &i ' C"&&+ "'/ H M"'%* #. C"&&+ H #

N%!$ *1

M"'%* P* /% &i ' N%!$ *2

M"'%* P* /% &i ' (51999 "/) (< /*- "/ /) ; (/*- M& -*) : (51999) (< /*- "/ /) ; (/*- M& -*) : C"'"/" +9


51/94

T"$+ 18. C"'"/i"' P* /% &i ' T%*< - M"'%* . T%*< - N%!$ * 8 M"'%* P* /% &i ' (51999 "/) (< /*- "/ /) ; (/*- M& -*) : C"'"/" )++;+0* *0*+*+ *0*::7N 6 %'/+"'/ "'/L"$*"/ * P*i' E/6"*/ I#+"'/ N 4" S &i" ;


52/94

Canadian Manure "our es Available 2or A and Gasi2i ation

C"&&+7>=

H #1>=

S 09=

C i < '37=

T%*< -9=

Fi %* :. Availability of Canadian Manures for A5 and &asification0

(otential (rodu tion o2 R&G 2ro Canadian Manures

!

!5#

!54

!5

!58

1

15#

154

15

158

& ' ( ) & " & B * C O & M B " + A B B C & , & - . +

C a n a

d a

(rovin e

M , C /

4 0 . r

A

Gas

Fi %* >. Potential Production of #4& from Canadian Manures

8+


53/94

7.2. FORESTRY WASTES

"orestry residues are made u' of forest o'eration residues and mountain 'ine

beetle @MPB residues @due to MPB infestations of forests in BC 0 "orest residues are

generated during harvest o'erations and subse uent >ood treatment in either sa>mills or

'ul' and 'a'er 'lants0 MPB residues are those generated from the unused 'art of the

infested >ood due to harvest o'erations, unsuitability as a >ood source and >aste

materials generated during the >ood treatment 'rocesses in sa>mills and 'ul' and 'a'er

'lants0 Production of "orestry >astes >as estimated from the data re'orted in the

Canadian biomass inventory by Wood and %ay$ell @)**7 for >ood 'roduction in

Canada0 We assumed that )*E of the 'roduced round>ood can be available for

gasification into #4&F >hile 9*E of the non(stem >ood left on site can be collected and

used for gasification into #4&0 -hese estimates are similar to those suggested by Wood

and %ay$ell @)**7 for Canada and by #alevic and %ay$ell @)**: for BC0 We also

estimated the forest residues from the MPB infestation and the e tra materials it 'rovides

for gasification to #4& from the BC data re'orted by #alevic and %ay$ell @)**: 0 -he

MPB residues are estimated to last for )* years and our data is re'orted as the annual

residue for )* years only0 &asification of the harvested forest residues to #4& is

assumed to occur >ith a 'rocess efficiency of :9E as discussed in 'revious sections0"orest residue data are 'resented in -able +; and sho>s that the 'otentially

available residues @minus MPB data are to be found mostly in BC @77E , ?uebec @);E

and .ntario @+;E 0 Adding the MPB residues increases the BC residues to 88E of the

Canadian total0 Potential 'roduction of #4& from these residues through gasification

@-able +; and "igure = sho>s a similar 'attern as the residue distribution0 -he 7

'rovinces of BC, ?uebec and .ntario account for ith BC alone making u' almost half of that total0 -otal Canadian

'otential #4& 'roduction from forest residues is estimated as +)0


54/94

Although this 'otential total 'roduction of #4& is technically feasible, one needs

to take into account the economic factors of this 'roduction, in 'articular the costs of

collection and trans'ortation of the residues to the gasification 'lants and the market

'rice of natural gas derived from fossil fuel sources0

T"$+ 1:. P & '&i"+ P* /% &i ' M & "' * ! C"'"/i"' F * #&*- W"#& #.

T &"+R %'/6 / 1

N ' S& !R #i/% 1

G"#i i"$+R %'/6 / 2

G"#i i"$+N ' S& ! 3

M %'&"i' Pi'B "&+ R #i/% #1

T &"+F * #&

R #i/% #7T &"+ CH7

G ' *"&i ' 8

(M& C -*) (M& -*)NL *0:< *08+ *0+7: *0)*9 *078+ *0+8s that

7*E to 9;E of the total MSW is from household sources >ith higher values in the /ast

and lo>er values are in Western Canada0 C >astes makes u' the highest fraction of the

total MSW >ith values ranging from 7;E to 98E >ith the higher values re'orted for

.ntario and Western Canada0 C5 >astes are the lo>est fraction and make u' from 9 to

))E of the Canadian total >ith higher values in BC and Alberta, likely due to increased

construction activity0

-he amounts of MSW that are amenable to A5 and gasification are re'orted in

-able +< and "igure ++0 We estimated that only )9E of the household >astes are

amenable to anaerobic digestion @.strem, )**8 0 4one of the other >astes >ere

considered to contain significant amounts of digestible >astes0 -his assum'tion

unfortunately underestimates the mount of digestible >aste by neglecting the amount offood >astes dis'osed of from restaurants and institutional cafeteria0 -he gasifiable >aste

89


57/94

T"$+ 1>. A''%"+ C"'"/i"' M%'i i0"+ S +i/ W"#& (MSW) P* /% &i ' (2998).

W"#& Di#0 #"+1 MSW O* "'i F*" &i ' S%$ & &

R #i/ '&i"+I'/%#&*i"+,

C !! * i"+ I'#&i&%&i '"+

C '#&*% &i ' D ! +i&i ' T &"+ AD

2 G"#i i "&i ' 3

(aste

uantities amenable to A5 ranged from 7 to 9E of the total dis'osed and the gasifiable

amounts from +7 to +9E0

&eneration of #4& from these >astes is 'resented in -able += and "igure +) andit sho>s that gasification can 'otentially 'roduce +0); Mt of #4& annually @=) to =7E of

the total 'otential #4& >hile A5 can 'roduce V *0+ Mt yr @9 to


58/94

T"$+ 1?. A''%"+ M & "' P* /% &i ' * ! C"'"/i"' M%'i i0"+ S +i/ W"#& # (2998).

M & "'

AD 1 G"#i i "&i ' 2 T &"+3

(aste collection and

trans'ortation is borne by the munici'alities0 -his 'otential source of #4& is significant

because of the cost offset and high degree of technical kno>ledge found in munici'al

>aste 'lants0 Although this 'otential 'roduction of #4& is technically feasible, one

needs to take into account the economic factors of this 'roduction, in 'articular the costsof gas cleaning and se'aration0

8;


59/94

Canadian Muni ipal "olid Waste isposal

!

$!!!

1!!!!

1$!!!

#!!!!

#$!!!

3!!!!

& '

( )

& "

& B

* C

O &

M B

" +

A B

B C

& ,

& -

. +

C a n a d a

7 9 t 0 y r 8

Res

:C:

C

,ot

Fi %* 19. Canadian Munici'al Solid Waste 5is'osal @)**9 0

!

$;!!!

1!;!!!

1$;!!!

#!;!!!

#$;!!!

3!;!!!

& ' ( ) & " & B * C O & M B " + A B B C & , & - . +

C a n a d a

7 d r y 9 t 0 y r 8

Canadian Available M"W

A

Gas

,ot

Fi %* 11. Availability of Canadian MSW for A5 and &asification as Com'ared to-otal 5is'osed MSW0

8


60/94

(otential R&G Generation 2ro Muni ipal Wastes

!5!

!5#

!54

!5

!58

15!

15#

154

15

158

& '

( )

& "

& B

* C

O &

M B

" +

A B

B C

& ,

& -

. +

C a n a d a

C /

4 7 M t 0 y r 8

A

Gas

Fi %* 12. Potential Production of #4& from Canadian Munici'al Solid Wastes

8=


61/94

7.3.2. W"#& 6"& *

Waste>aters are the mi ed li uid and solid >astes collected through se>ers and

delivered to a >aste>ater treatment 'lants0 -hese >astes can 'roduce #4& throughanaerobic digestion in large digesters >here some of the biomass solids are converted

into CH 8 and C. ) 0 -his 'ractice is common for larger munici'alities >here the original

aim >as to reduce the solids contents of the >astes before discharge form the 'lants0

We estimated the generation for >aste>aters for each 'rovince and the >hole

country from /nvironment Canada data @/nvironment Canada, )**+ for the Canadian

generation in +=== and the 'o'ulation si$es of 'rovinces and Canada in )**: @Statistics

Canada, )**;e 0 /nvironment Canada also re'orted that =;E of the Canadian 'o'ulation

is served >ith some form of >aste>ater treatment0 -able )* 'resents the data for

>aste>ater generation and 'redictably, the highest amounts correlate >ith the highest

'o'ulations, making .ntario and ?uebec the largest 'roducers of >aste>aters in the

country0

-he 'otential #4& 'roduced from the anaerobic digestion of these >astes is

'resented in -able )* and "igure +70 We estimated the 'roduction of #4& using data

re'orted for many .ntario >aste>ater anaerobic digesters by Wheeldon et al0 @)**9 ,

>here the s'ecific methane 'roduction >as re'orted as *0*77: m 7 CH 8 m7 >aste>ater0

-he total Canadian 'otential #4& 'roduction from >aste>aters is estimated to be V

*0+)8 Mt yr and 'rovincial 'roduction correlates >ith 'o'ulation si$e0 -his #4& amount

does not look significant e ce't for the fact that many of these facilities e ist already and

the only cost incurred to 'roduce #4& is through cleaning of the 'roduced biogas and

se'aration of the CH 8 and C. ) from this biogas0 -hus the cost of 'roducing #4& from

this source is relatively chea'er and technologically easier0

Although this 'otential 'roduction of #4& is technically feasible, one needs totake into account the economic factors of this 'roduction, in 'articular the costs of gas

cleaning and se'aration0

9*


62/94

T"$+ 29. A''%"+ M & "' P* /% &i ' * ! C"'"/i"' W"#& 6"& *# (299;)

P 0%+"&i '1 W"#& 6"& * P* /% &i ' CH 7 P* /% &i '

(0 *# '#) (!3 /) 2 (M !3 -*) 3 (M !3 -*) 7 (


63/94

(otential (rodu tion o2 R&G 2ro Canadian Waste


64/94

7.3.3 Bi # +i/#

Biosolids are the solids collected through solid li uid se'aration of the

>aste>aters before li uid discharge from the >aste>ater treatment 'lant0 Some of these

>aste>aters >ould have undergone anaerobic digestion 'reviously0 Currently, Biosolids

are dis'osed on land, landfills or com'osted0

We estimated the amount of Biosolids 'roduced in Canada from the 'o'ulation

si$e and the s'ecific Biosolids 'roduction rate of *0*:7 kg @dry Biosolids 'erson day

@Klass, +==< 0 -hus, Biosolids uantities correlate >ell >ith 'o'ulation si$e0

Production of #4& from Biosolids is through gasification of the dried Biosolids0

We assumed that the carbon content of the Biosolids to be 8*E according to Klass @+==astes0 -he

large biomass uantities collected in these landfills after closure tends to anaerobicallydigest naturally to 'roduce CH 8 and C. ) 0 Most of the 'roduced gases esca'e to the

atmos'here but in some landfills, are collected and harnessed to 'roduce 'o>er0

-able )) sho>s the data for the estimated methane generation from Canadian

landfills0 -he data also sho>s the amounts of methane ca'tured and by difference from

the generated values, the amount emitted to the atmos'here @-able )) and "igure +9 0

/mitted methane gas is considered a greenhouse gas >ith 'otential activity e uivalent to

)+ times that of C. ) 0 -able )) sho>s the amounts of greenhouse gas emitted @as C. )

e 0 due to the release of methane from landfills0 Predictably, most of the generated

methane is found in .ntario and ?uebec, the largest 'rovincial 'o'ulations in CanadaF

smaller amounts are found in BC and Alberta0 Most of the ca'tured landfill methane is

found in .ntario @);E of the emitted , ?uebec @7+E , 4ova Scotia @+8E , BC @+9E and

Alberta @9E >ith much lesser uantities @ +E in the other 'rovinces0

-otal 'otential #4& generation from Canadian landfills is estimated at +089 Mt yr

@-able )) >ith only )+E ca'tured0 -he 'otential e ists to increase the ca'ture of the

generated methane due to the availability of established technology for landfill gas

ca'ture, cleaning and se'aration into CH 8 and C. ) 0

-his #4& amount is significant es'ecially >hen one considers that many of these

facilities e ist already >here the cost of >aste collection and 'lacement is already

incurred by munici'alities0 -he only cost incurred to 'roduce #4& is through cleaning

of the ca'tured landfill gas and se'aration of the CH 8 and C. ) from this biogas0 -hus,

the cost of 'roducing #4& from this source is relatively chea'er and technologically

easier0Although this 'otential 'roduction of #4& is technically feasible, one needs to

take into account the economic factors of this 'roduction, in 'articular the costs of gas

cleaning and se'aration0

9:


68/94

T"$+ 22. A''%"+ M & "' G"# G ' *"&i ' "'/ C"0&%* * ! C"'"/i"' L"'/ i++# (2998).

M & "'

G ' *"&i '1

GHG

G ' *"&i '2

LFG

0*

M & "'

C"0&%* /3

M & "'

E!i&& /7

GHG

E!i&& /2

(


69/94

R&G (rodu tion in Canadian 'and2ills

!

#!!;!!!

4!!;!!!

%!!;!!!

8!!;!!!

1;!!!;!!!

1;#!!;!!!

& ' ( ) & " & B * C O & M B " + A B B C & , & - . +

C a n a

d a

C / 4

7 9 t 0 y r 8

Captured

) itted

Fi %* 18. Potential Production of #4& from Canadian %andfills0

9


70/94


71/94

T"$+ 23. A''%"+ P & '&i"+ P* /% &i ' M & "' * ! C"'"/i"' M%'i i0"+ W"#& #.

LFG MSW W"#& 6"& * Bi # +i/# T &"+

AD G"#i i "&i ' T &"+ AD G"#i i "&i '

(


72/94

(otential R&G Generation 6ro Muni ipal Wastes

!5!!!

!5#!!

!54!!

!5%!!

!58!!

15!!!

15#!!

154!!

15%!!

158!!

& '

( )

& "

& B

* C

O &

M B

" +

A B

B C

& ,

& -

. +

C a n a

d a

C H 7

( < & A - * )

A5

&as

Fi %* 1:. Potential #4& Source of Production from Munici'al Wastes0

(otential ,otal (rodu1tion o2 R&G 2ro3 Canadian

Muni1ipal Wastes

!

1;!!!

#;!!!

3;!!!

4;!!!

$;!!!

& '

( )

& "

& B

* C

O &

M B

" +

A B

B C

& ,

& -

. +

C a n a d a

C /

4 7 9 t 0 y r 8

Fi %* 1>. Potential -otal Production of #4& from Canadian Munici'al Wastes0

:+


73/94

8. PRODUCTION OF METHANE FROM CANADIAN WASTES

-his section >ill address the technical feasibility of 'roducing #4& from

Canadian >astes and an economic analysis of it0

8.1 TECHNICAL FEASIBILITY

We define technical feasibility as the 'otential to reali$e a 'roduct based on the

availability of resources and the 'rior kno>ledge and e 'erience of using similar

'rocesses for 'roducing similar 'roducts0 Production of #4& from Canadian >astes >as

sho>n to arise from the a''lication of t>o >ell used and understood 'rocessesD

Anaerobic digestion and gasification0

Anaerobic digestion is a naturally occurring 'rocess that has been used

industrially to 'roduce biogas from agricultural, munici'al and industrial 'rocess @food

'rocessing 0 Production of #4& adds the 'rocesses of biogas cleaning and gas

se'aration to the anaerobic digestion 'rocess0

&asification is an old industrial 'rocess that has been used mainly to 'rocess coals

into gaseous 'roducts and to further use these gases to 'roduce energy0 &asification of

coal into #4& has been demonstrated in the 1S and /uro'e0 -he a''lication of the

technology has until recently been limited by the lo> 4& 'rices0 &asification of >astesis an established 'rocess >here the 'roduced syngas is used to 'roduce energy0

/ am'les of using this technology for various >astes are found mostly in /uro'e and to a

lesser degree in 4orth America0 Syngas is made u' of hydrogen, carbon mono ide and

smaller amounts of methane0 Production of #4& through gasification thus re uired the

cleaning of the syngas, methanation and further se'aration into methane and carbon

dio ide0 Methanation has been industrially a''lied in /uro'e for coal but much less for

>aste gasification0 -he 'rocesses of gas cleaning and se'aration are common to both

anaerobic digestion and gasification0 &as cleaning is de'endent on the nature of

contaminants to be removed and thus the source of the biogas syngas0 Most

contaminants can be removed by e isting 'rocesses that have been a''lied industriallyF

the challenge is to integrate these technologies into the #4& 'roduction chain0 Similarly,

:)


74/94

gas se'aration has been 'racticed for many industrial 'rocesses and the challenge is to

ada't the e isting technologies into the #4& 'roduction 'rocess0

Based on our findings, it is envisioned that anaerobic digestion 'rocess >ill be the

main source of #4& in the ne t 9 to +* years >ith gasification contributing after>ards0

-his is based on the availability of the technologies, 'rior use and acce'tance by industry

and the need for further technology develo'ment activities0

A summary of all 'otential #4& that can be 'roduced from Canadian >astes is

'resented in -able )8 and "igure +=0 -he data sho>s that a 'otential total of )80= Mt yr

of #4& can be 'roduced Canadian >astes0 "orestry seems to have the 'otential to

'roduce +)0= Mt yr @9+E of total , follo>ed by astes to 'roduce #4&0

-he use of gasification has the 'otential 'roduce most of the #4& in Canada as

>e estimated that )+ Mt yr @


75/94

T"$+ 27. P & '&i"+ M & "' P* /% &i ' * ! C"'"/i"' W"#& # A *i %+&%* W"#& # F * #&*- M%'i i0"+ W"#& # T &"+ M"'%* C* 0# R #i/% # MSW L"'/ i++ WW Bi # +i/#

AD G"# AD G"# G"# AD G"# AD AD G"#(M& -*)

NL *0****0**

+*0**

**0**

* *0+813%

Contribution o2 Wastes to R&G (rodu tion

Fi %* 29. Contribution of Wastes to #4& Production0

359

#15!

#459

!5!

$5!

1!5!

1$5!

#!5!

#$5!

3!5!

A Gas ,otal

C / 4 7 M t 0 y r 8

Contribution o2 R&G ,e hnolo=y to R&G (rodu tion

Fi %* 21. Contribution of #4& -echnology to #4& Production0

::


78/94

T"$+ 28. P & '&i"+ RNG "# " F%' &i ' E' * - P* /% &i ' "'/ C%** '& NGC '#%!0&i '

T &"+ P & '&i"+

CH 7 G ' *"&i ' E' * - E+ &*i i&- NG C '#%!0&i ' T &"+ P & '&i"+

CH 7 G ' *"&i ' (M& -*) (PJ -*) (GW ) (M& -*) (= NG)

NL *0)+< +)0); 7,8*ithout u'grading the gas and 'roducing only 'o>er0

70 A gasification 'lant 'rocessing forest biomass @slash, bug kill, fire kill etc

and 'roducing 'o>er and heat for an ad6acent 'ul' mill0 -his model could

'otentially be ada'ted to agricultural cro' residues as >ell0

80 A large landfill near /dmonton 'roducing biogas for 'o>er generation0

-he models are constructed based on a series of assum'tions on revenues, ca'ital

costs and o'erating costs to calculate /B -5A @/arnings Before nterest, -a es,

5e'reciation and Amorti$ation as >ell as 're( and 'ost(ta 'rofit and rates of return0

-he models are intended to 'roduce a Qsna'shotR of a ty'ical year s o'eration and are not

reflective of ongoing changes to the business during a full business cycle0 .ur intent is torefine the information and e 'and the models accordingly to im'rove their utility as an

analytical and decision making tool0

tems like de'reciation are estimated based on a very rough estimate of the ca'ital

cost asset classes for each 'lant0 t also assumes straight line de'reciation versus

declining balance0

-he model assumes +**E debt financing for each case >ith interest at :E0 So a

'ro6ect that returns a 're(ta return of *E is actually generating a Q-rueR rate of return of

:E0 -he /B -5A value is em'loyed so that rates of return can be com'ared inde'endent

of de'reciation schedules and financing charges0 A 8*E /B -5A is considered as ideal

and 7*E /B -5A as being the minimum acce'table return0

:


80/94

8.2.1 E#&i!"&i' & E ' !i "++- R 4 *"$+ R # %*

With good assum'tions about the state of technology and thereby the ca'ital and

o'erating costs, as >ell as revenue and ra> material costs, >e can determine the o'timal

'lant si$e to e 'loit the available resource0 While >e have estimates on the total landfill

gas resource, as an e am'le, >e >ould need to kno> >hat the o'timal si$ed 'lant >ould

be that can generate a satisfactory investor grade return for a minimal si$ed landfill0 We

can then assume that any larger landfill >ill generate even better returns and calculate a

Qrecoverable reserveR value0 Similarly, >e >ill be able to assess ho> this economically

e 'loitable reserve increases as gas and or 'o>er 'rices change due to market forces or to

changes in 'ublic 'olicy >ith res'ect to subsidies0

8.2.2 Pi0 +i' 4 *#%# P 6 *

5evelo'ing these basic s'readsheets highlights the com'le ity around a

fundamental uestion0 s it better to 'roduce 'o>er or a 'i'eline grade gas At the

moment, there is very little data on the cost to clean gas to a 'i'eline grade0 But if this

ca'ital cost is lo>er than the cost of installing 'o>er generation e ui'ment, then it may

be 'referable to make gas rather than 'o>er sub6ect of course to the 'rice of QgreenR gas

being higher than QgreenR 'o>er and sub6ect to there being available customers for

'o>er0

What information >e do have about gas cleaning costs suggests that the best use

for biogas given the current state of the technology is for 'o>er generation0 A study by

/lectriga$ -echnologiesD X"easibility Study ( Anaerobic 5igester and &as Processing

"acility in the "raser 3alley, British ColumbiaX uotes a biogas u'grading cost of

Y809 million for a =9,*** &G year 'lant0 -his is e ual to Y8; &G0 A study by the 1S5/

QBiogas Multi(!ear ProgramR states that in the case of a forest biomass gasification

'lant, biogas u'grading costs are e 'ected to be t>o times higher than the cost of

feedstock 'rocurement and gasification itself0 n other >ords, converting biogas to 'o>er

rather than u'grading to 'i'eline grade gas results in a 'roduction cost 6ust over one third

less0

:=


81/94


82/94

Return on :nvest ent vs Capital Cost? 6eedlot Bio=as to (ipeline Grade" anario

"6#0

"4#0

"2#0

0#0

2#0

4#0

6#0

#0

200 2$0 %00 %$0 400 4$0

Capital Cost 7 illion @

A 2 t e r

, a

R e

t u r n o n

: n v e s

t 3 e

Fi %* 23. /conomic Analysis of "eedlot Biogas to Pi'eline &rade #4&

;+


83/94

8.2.3 Ri#< S '#i&i4i&- "'/ Mi&i "&i ' A'"+-#i#

-hese models >ere hel'ful in e 'loring risk sensitivity analysis in the different

scenarios0 "eedlot manure 'lants, for e am'le, are highly e 'osed to trans'ortation cos

methane from wastes

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