14th North American Waste to Energy Conference
May 1-3,2006, Tampa, Florida USA
NAWTEC14-3196
PYROLYSIS IN WASTE TO ENERGY CONVERSION (WEC)
Alex E. S. Green and Sean M. Bell
Clean Combustion Technology laboratory (CCTl),
College of Engineering, University of Florida, Gainesville, Fl
fuels and are increasingly importing our gaseous fuels
(now>15%). Our country is now shedding Blood in its efforts
to stabilize regions of the globe that supply these premium
fuels. Yet the US is well endowed with solid fuels in the form
of wasted solids as well as coal and oil shales. In this paper, in
continuation of a long search for altematives to oil [1-10], our
focus is on converting our solid waste to energy by advanced
thermal technologies (SWEATT). Table 1 is a list of US's
abundant supply of wasted solids or solid waste whose organic
matter can be made into liquid and gaseous fuels. With recent
high natural gas prices and technical reasons that will become
obvious this paper will concentrate on advanced thermal
technologies (ATT) conversions of solid waste (SW) to
gaseous fuels. ATT conversions to liquid fuels involve similar
technical considerations but the oil back-out problem has the
attention of many government, business and engineering
personnel. SWEATT has the attention of only a few.
In the US most of the categories in Table I would now
be called "biomass" in part because "solid waste" has a bad
public image, bringing to mind old incinerators belching black
smoke. However, advances in thermal technologies and gas
clean-up systems now being successfully applied in Japan and
the European Union (EU) [11] deserve a new image.
SWEATT not only addresses US's very urgent need for
alternative fuels, but could also mitigate air and water
pollution problems. The large carbon dioxide neutral plant
matter components in Table I can help in Greenhouse
mitigation. The great diversity of physical and chemical
characteristics in Table I implies that the world now needs an
"omnivorous feedstock converter" (OFC) to change these
solid fuels into much more usable liquid or gaseous fuels.
Figure 1 is a conceptual illustration of an OFC adapted from a
number of prior CCTL papers [8-10].
Figure 2 shows the subdivisions of the US total primary
energy supply (TPES) in 2005. The data (in quadrillion
British thermal units (Btu) or quads) is taken from the January
to October 2005 monthly numbers given in US Energy
Information Agency website [12] augmented with estimates of
the November and December 2005 consumptions. Since the
total consumption is now very close to 100 quads the numbers
might also be considered as approximate percentages of US
energy consumption. It is seen that over 40% of our energy
consumption is in the form of oil that is mainly consumed in
our transportation sector. Without doubt the biggest energy
problem faced by the US today, as has been recognized for
many years, is the need to find alternatives to oil [1-3]. In the
70's and early 80's the CCTL focus was on alternatives to oil
in the utility sector.
At this time, our focus is on the
developing alternatives to natural gas for electricity generation
ABST RACT
Solid waste (SW), mostly now wasted biomass, could fuel
approximately ten times more of USA's increasing energy
needs than it currently does. At the same time it would create
good non-exportable jobs, and local industries. Twenty four
examples of wasted or under-utilized solids that contain
appreciable organic matter are listed. Estimates of their
sustainable tonnage lead to a total SW exceeding 2 billion dry
tons. Now usually disposal problems, most of these SW's, can
be pyrolyzed into substitutes for or supplements to expensive
natural gas. The large proportion of biomass (carbon dioxide
neutral plant matter) in the list reduces Greenhouse problems.
Pyrolysis converts such solid waste into a medium heating
value gaseous fuel usually with a small energy expenditure.
With advanced gas cleaning technologies the pyrogas can be
used in high efficiency gas turbines or fuel cells systems. This
approach has important environmental and efficiency
advantages with respect to direct combustion in boilers and
even air blown or oxygen blown partial combustion gasifiers.
Since pyrolysis is still not a predictive science the CCTL has
used an analytical semi-empirical model (ASEM) to organize
experimental measurements of the yields of various product
{CaHbOc} yields vs temperature (T) for r dry ash, nitrogen and
sulfur free (DANSF) feedstock having various weight % of
oxygen [0] and hydrogen [H]. With this ASEM each product
is assigned 5 parameters (W, To, D, p, q) in a robust analytical
YeT) expression to represent yields vs. temperature of any
specific product from any specified feedstock. Patterns in the
dependence of these parameters upon [0], [H], a, b, and c
suggest that there is some order in pyrolysis yields that might
be useful in optimize the throughput of particular pyrolysis
systems used for waste to energy conversion (WEC). An
analytical cost estimation (ACE) model is used to calculate the
cost of electricity (COE) vs the cost of fuel (COF) for a SW
pyrogas fired combined cycle (CC) system for comparison
with the COE vs COF for a natural gas fired CC system. It
shows that high natural gas prices solid waste can be changed
from a disposal cost item to a valuable asset. Comparing
COEs when using other SW capable technologies are also
facilitated by the ACE method. Implications of this work for
programs that combine conservation with waste to energy
conversion in efforts to reach Zero Waste are discussed.
1. WASTED SOLIDS AND SOLID WASTE
In 1940, when Britain was in deep trouble fighting a
ruthless enemy that then appeared unstoppable, Winston
Churchill offered only "Blood, Sweat and Tears" to unite
Britain's political factions. At this time in our history we are
excessively (60%) reliant on foreign sources for our liquid
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Copyright © 2006 by ASME
via the use of advanced thermal technologies (ATT). It should
be noted, however, that ATT can also make major
contributions to the solution of our liquid fuel problem in the
transportation sector [3].
It is important to differentiate secondary energy supplies
(SES) from the primary energy supplies (PES) shown in
Figure 2. Secondary energies supplies include steam, syngas,
reactive chemicals, hydrogen, charged batteries, fuel-cells and
other energy sources that draw their energy from PES's. If a
SES is converted to another type of energy, say mechanical
energy, via a steam turbine the mechanical energy becomes a
tertiary energy supply (TES). This TES can be converted to
electrical energy using magnetic generators in which case the
electricity is a quaternary (QES) supply. In the case of
electricity the many conversions are usually justified since
electricity can readily be distributed by wire and has so many
uses as a source of energy for highly efficient electric motors,
illumination systems, home appliances, computers, etc.
A debate is underway in many communities as to
whether its increasing electricity needs should be met with
solid fuels, particularly coal, via conventional steam and steam
turbine generator systems or via conversion to a gaseous fuel
to fuel gas-steam turbine-generator systems. Granting that the
steam turbine route has had many advances over the last
century our thesis is that converting the solid fuel to gaseous
fuel is the advanced thermal technology (ATT) route of the
future. The ATT route is not only driven by environmentally
acceptable waste disposal needs and increased needs for
electricity but also by the need for liquid fuels and gaseous
fuels. A number of petroleum resource experts have recently
advanced the date that the globe's supply of oil and natural gas
will run out. The prices of oil and natural gas that now might
be reflecting this drawdown and are already high enough that
conversion of organic matter in solid waste to liquid and
gaseous fuels makes economic sense. We should recognize,
however, that for the most part cartels govern fuel prices not
free markets. Thus we should not abandon alternative fuels
efforts whenever cartels, for their interests, lower prices.
The solid wastes listed in Table I, mostly consisting of
what is called biomass in the US, now constitute a minor
component (-2.8 %) of the U.S. annual TPES. However, this
wasted material could in the near term become a major (>
25%) component comparable to coal and natural gas, both
now at about 23%. Since SWEATT is based upon locally
available solid waste, it would also create good non-exportable
local industries and jobs while mitigating serious U.S. energy
import and waste disposal problems. An Oak Ridge National
Laboratory study [12] estimates the sustainable supply of the
first few biomass categories in Table I at about 1.4 billion dry
tons. The remaining categories should readily bring the total
sustainable U.S. solid waste available to over 2 billion dry
tons. Assuming a conservative higher heating value (HHV) of
7500 Btullb a simple calculation shows that with SWEATT
US solid waste contribution to its primary energy supply could
reach the 25% level with technologies close to those that are
now in place in Japan, EU and a few places in the US [11].
Essentially the U.S. now consumes about 100 quadrillion
BTUs (British thermal units), only about 2.8% of which
currently come from solid waste. The other renewables,
hydroelectric (2.8%), geothermal (0.35%), wind (0.14%) and
solar (0.06%), have much further to go than solid waste before
becoming a major primary energy source in the US.
Copyright © 2006 by ASME
2. ADVANCED THERMAL TECHNOLOGIES
The largest solid waste to energy systems in operation
today are direct combustion municipal solid waste (MSW)
incinerators [14] with capacities in the range of 1000 to 3000
tons per day. In such mass bum systems the organic
constituents of the solid waste are combusted (in a sense
converted!) into the gaseous products CO2 and H20. These
have no fuel value but can be carriers of the heat of
combustion, as in coal and biomass boiler-furnace systems.
Along with the flame radiation these gases transfer hest to
pressurized water to produced pressurized steam that drives a
steam turbine driven electric generator. The steam can also
serves as valuable secondary energy supply (SES) to distribute
heat for heating buildings, industrial processes etc. The
production and use of steam along with the steam engine
launched the industrial age and various steam driven systems
have reached a very high level of refinement including in
waste to energy systems[14].
In SWEATT systems, rather than direct combustion and
the use of the heat released to raise steam the solid waste is
first converted into a gaseous or liquid fuel. This fuel then
serves as a SES that can be combusted in efficient internal
combustion engines, combustion turbines or, in the future, in
fuel cells none of which can directly use solid fuels. Over the
past century automotive and aircraft developments have
pushed internal combustion engines (ICE) and gas turbines
(GT) to very high levels of efficiency. Furthermore, with the
use of modem high temperature GTs Natural gas-fired
combined cycle (NGCC) systems the heat of the exhaust gases
can be used with a heat recovery steam generator (HRSG) to
drive a steam turbine. The HRSG can alternatively provide
steam for combined heat and power (CHP) system that can
effectively make even greater use of the original solid fuel
energy.
If one considers the US's heavy dependence on foreign
sources of liquid and gaseous fuels the most challenging
technical problem facing us today should be recognized as the
development and implementation of efficient ways of
converting our abundant domestic solid fuels into more useful
liquid and gaseous fuels. In view of the diversity of feedstock
represented in municipal or institutional solid waste any
successes in Solid Waste to Energy by Advanced Thermal
Technology (SWEATT) would obviously advance this more
general quest. In effect the US and the world needs an
omnivorous feedstock converter such as is illustrated in Figure
1. Here the right block represents a typical gas fired combined
cycle system whereas the left block represents a conceptual
Omnivorous Conversion System that can convert any organic
material into a gaseous fuel.
3. GROSS COMPARISONS OF ATT OUTPUTS
We will first consider the gross nature of the output
gas from biomass or cellulosic type material, the major
organic components of most solid wastes streams. Apart from
minor constituents such as sulfur and nitrogen the cellulosic
feed types are complex combinations of carbon, hydrogen and
oxygen in combinations such as (C6HIOOS) that might serve as
the representative cellulosic monomer.
SWEATT systems might be divided into 1) Air
Blown Partial Combustion (ABPC) gasifiers 2) Oxygen blown
Partial Combustion (OBPC) gasifiers and 3) Pyrolysis
(PYRO) systems. The three approaches for converting waste
into a gaseous fuel have many technical forms depending upon
150
the detailed arrangements for applying heat to the incoming
feed and the source of heat used to change the solid into a gas
or liquid.
Let use "producer gas" as a generic name for gases
developed by partial combustion of the feedstock with air as in
many traditional ABPC gasifiers that go back to Clayton's
coal gasifier of 1694. We will use "syngas" for gases
developed by partial combustion of the feedstock with oxygen
as in OBPC gasifiers, which are mainly a development of the
20th century. We will use "pyrogas" for gases developed by
an-aerobic heating of the feedstock such as in indirectly heated
(PYRO) gasifiers. Our objective is to replace natural gas that
has a HHV-lOOO BtU/cft = I MBtu/cft (here M= 1000).
When an ABPC gasifier is used with cellulosic materials
(cardboard, paper, wood chips, bagasse, etc), the HHV of
biomass producer gas is very low 100-200 BtU/cft for two
reasons 1) the main products are CO that has a HHV of 322
Btu/cft and CO2, and H20 that have zero heating values and 2)
the air nitrogen air substantially dilutes the output gas.
The "syngas" obtained from biomass with an OBPC
gasifiers is better - 320 Btu/cft since it is not diluted by the
atmospheric nitrogen. However, it is still somewhat lower than
the feedstock molecules because of the partial combustion.
The oxygen separator is a major capital cost component of an
OBPC gasifier.
With a PYRO system the original cellulosic polymer is
first broken to its monomers leading to some CO , CO2, and
H20 along with paraffins (CH4, C2H6 and C3HS..), olefins
(C2H4, C3H6..) and oxygenated hydrocarbons: carbonyls,
alcohols, ethers, aldehydes and phenols and other oxygenated
gaseous products. Cellulosic pyrogas can have heating values
in the 400Btulcft range.
Hydrocarbon plastics such as polyethylene and
polyolefins in general are among the most predominant
plastics in many solid waste streams. Thus one might use
(C2H4) as representative of the monomers in the plastic
component of MSW or refuse derived fuels (RDF).
Polyethylene pyrolysis products include H2, olefins, paraffins,
acetylenes, aromatics (Ar) and polynuclear aromatics (PNA).
On a per unit weight basis all but H2 have gross heating values
in the range 23-18 MBtuilb (M=lOOO), similar to oil, whereas
H2 has a gross heating value of 61MBtu/lb. On a per unit
volume basis all polyethylene pyrolysis products have gross
heating value ranging from 1-5 MBtu/cft whereas H2 is 0.325
MBtulcft = 325 Btu/cft. Natural gas is typically about
IMBtulcft. Thus we would expect the pyrogas from
polyethylene to have a gross heating value comparable or
greater than that of natural gas and much greater than
cellusosic pyrogas.
In summary since cellulosic feedstock is already
oxygenated as compared to pure hydrocarbon plastics its
pyrogas, syngas and producer gas will all have considerably
lower heating values than the corresponding gases from
hydrocarbon feedstock. From the viewpoint of maximizing the
HHV of SW derived gas PYRO gasification scores better than
OBPC gasification that scores better than ABPC gasification.
initial CCTL studies, it has been customary to characterized
the feedstock by its atomic ratios y = H/C and x = OIC [1520). In its recent studies [21-26]the CCTL has found it more
advantageous to work with the weight percentages [C], [H]
and [0] of the feedstock after correcting to dry, ash, sulfur and
nitrogen free (DASNF) conditions (i.e. pure CHO materials).
Figure 3A illustrates [H] vs. [0] coordinates of 185
representative coals and biomass based upon ultimate analyses
that have been reported in the literature. Note the simple
analytical [H] vs. [0] coalification curve (see figure) and the
hovering of the values of the coal and biomass [H] values near
6% after the anthracite region. The larger points on Figure 3A
give the [H], [0] positions of lignin (6.1,32.6), cellulose
(6.2,49.4) and hemi-cellulose (6.7,53.3), the three main
components of all plant matter. Also shown on Figure 3A are
the [H] and [0] co-ordinates of several materials that are
present in solid waste. These depart substantially above and
below the coalification curve. Not shown is polyethylene that
would lie at [14.2, 0).
Figure 3B shows the total volatiles (VT) for the CHO
materials vs. [0] mostly for materials close to the coalification
path. These values are determined by standard proximate
analysis procedures that measure the weight loss of a sample
after exposure to 950°C for 7 minutes in an anoxic medium.
The balance from 100% then represents the weight of the
fixed carbon (FC) plus ash. When this residual is burnt the
remainder is the ash wt%. An empirical analytical formula is
given in the caption to represent general trends of total
volatiles along nature's coalification curve. It should be
obvious that in the high [0] region pyrolysis is substantially
equivalent to gasification. Our subsequent studies point to the
fact that the [H] dimension is very important in determining
volatile content.
Figure 3C shows the pattern of higher heating values
(HHV) vs [0] along the coalification path. The DuLong
formula given in the caption is a compromise between those
used in the coal and biomass sectors [14, 28). The three
diagrams all indicate the importance of the [0] in determining
the fuel properties of natural substances. A better expression is
needed to represent the total volatile released when [H] lies
above the coalification curve.
5. ASEM AND PYROLYSIS
Proximate analyses of coal and biomass measured for
over a century provide extensive data on total volatile content.
However, the identification of the molecules in these volatiles
is still not available for practical engineering applications and
remains in the engineering research stage. For the optimum
control and application of a pyrolysis system it would be
useful to know in detail the expected yields of specific
pyrolysis product from various feedstocks.
The Clean Combustion Technology Laboratory (CCTL)
of the University Florida has made a number of attempts to
find the underlying order of pyrolysis yields of any product
CaHbOc vs the [0] and [H] of the DASNF feedstock and the
temperature (T) and time (t) of exposure. Since [C] = 100-[0]­
[H] it is not an independent variable. Table 2 gives
representative slow pyrolysis yields at 1000°C measured at the
CCTL during the course of these attempts [17]. In organizing
such data as well as data in the literature the CCTL has
developed an analytical semi-empirical model (ASEM) that
has been useful for a number of applications of pyrolysis [1927). Attempts have been made to include the time dimension
but much more work remains. When the time dimension is
4. ULTIMATE AND PROXIMATE ANALYSIS
To optimize the use of the US supply of solid waste
listed in Table 1 it would be helpful to know in greater detail
how the main constituents of organic containing feedstock will
influence the main products that will evolve from ATT. In
most attempts to find the systematic of pyrolysis yields of
organic materials such as coal and biomass including the
151
Copyright © 2006 by ASME
temperature based upon fits to the experimental data of
Mastral et al [32, 33] at five temperatures that were
constrained to approximately satisfy mass, carbon and
hydrogen balances.
Once the parameter systematics is
identified the ASEM representation can be used to estimate
the pyrolysis product of polyethylene pyrolysis at any
intermediate temperature or at reasonable extrapolated
temperatures. The experimental data was only available up to
850°C but the extrapolations to 1000°C were constrained in
detail to conform to mass, carbon, hydrogen and oxygen
balance. Figure 4 also shows extrapolations to 6000 C that
might be of interest if one goes to very high temperatures, for
example by plasma torch heating. Here we incorporate a
conjecture that at the highest temperatures carbon and
hydrogen emerge among the products at the expense of the
CI-C2, aromatics and PNAs components. While we have
already found that an ASEM can begin to bring some order
and overview into pyrolysis yields clearly we have a long way
to go. When the time dimension is important the overall
search is for a reasonable function of seven variables [H], [0],
a, b, c, T, and t. Einstein special relativity only dealt with a
four variables x,y,z and t.
not a factor the yields of each product for slow pyrolysis (or
fast pyolysis at a fixed time) are represented by
YeT) = W[L (T: TO, D)]p[F (T: TO, D)]q
(1)
where L (T: TO, D) =1/[1 + exp «TO -T)/D)]
(2)
F(T: TO, D) =I-L(T) = 1/[ l+exp «T - TO)/D)] (3)
and
Here L(T), is the well known logistic function that is
often called the "learning curve". Its complement F(T) = 1L(T) thus might be called the "forgetting curve". In effect each
product is assigned 5 parameters (W, To, Do, p, q) to represent
its yield vs. temperature profile. The objective has been to find
how these parameters depend upon the [H] and [0] of the
feedstock and the a, b, c of the CaHbOc product for the data
from various types of pyrolyzers. Studies by Xu and Tomita
(XT) [28, 29] that gave data on IS products from 17 coals at 6
temperatures have been particularly helpful in revealing trends
of the parameters with [0] and [H]. In applying the ASEM to
the CCTL data collection, the XT collection and several other
collections a reasonable working formula was found for the
yield of any abc product for any [0], [H] feedstock. It was
given by
6. SWCC VS NGCC AND
where z = [C]/69, h = [H]/6 and x = [0]/25 and The
parameters a, � an9 Y. To, D, p and q were found to have
simple relationships to the feedstock and product defining
parameters a, b, c [H] and [0]. The final ASEM formulas that
fit the data could then be used to extrapolate or interpolate the
XT results to any [H], [0] feedstock and temperature. Figure 4
gives an overview of the interpolated and extrapolated outputs
Y(T) outputs for a selection of products for four representative
feedstock along natures coalification path.
Since hundreds even thousands of organic products of
pyrolysis have been identified in the literature to go much
further some comprehensive organization of these products is
needed. Towards this goal the CCTL has grouped products
into the families shown in Table 3 along with the a,b,c rules
that connect these groups. This list can be subdivided into pure
hydrocarbons i.e. (C.Hb) and the oxygenates (C.HbO, CaHb02,
CaHb03 etc). Isomers (groups with identical a, b and c) can
differ in detailed pyrolysis properties and hence parameters.
We use j = 1, 2, 3 etc... to denote the first, second, third, etc.
members of each group or the carbon number (n). In the
CCTL's most recent studies [21-27] of specific feedstock
pyrolysis formulas have been proposed and tested for the
dependence of the W, To, Do, p, q parameters upon the carbon
number of the product within each group. This makes it
possible to compact a very large body of data with simple
formulas and a table of parameters.
The case of polyethylene is an example of such a study.
It is not shown on Figure 3A, as it is far removed from the
coalification curve having the position [H] =14.2 on the [0] =
o axis. Without oxygen in the feedstock the pyrolysis products
are much fewer and the ASEM is much simpler to use than
with carbohydrates. Thus only the first 5 rows of Table 3 are
needed to cover the main functional groups involved in the
organizing the pyrolysis products of polyethylene. Figure 5
gives an ASEM type summary of the product yields vs.
(5).
Y(X)=K+SX
• . .
Copyright © 2006 by ASME
ACE
Before World War II also every town had its own gas
works, mainly using coal, as a feedstock. After WW II cheap
natural gas became available and became a major PES for
home heating and cooking as well as for industrial purposes.
In the 1980s factory produced NGCC became available and
natural gas became a base load fuel source for many electric
utilities hastening the drawdown of US domestic supplies. In
the last four years natural gas prices have risen to some 3-7
times greater than they were when these NGCC facilities were
built. Thus pursuing SW to energy by advanced thermal
technologies (SWEATT) is now a very timely. For most
biomass and plastic feedstock pyrolysis is substantially
equivalent to gasification.
The economic feasibility of using a gasifier in front of a
gas fired system can be examined with simple arithmetic and
algebra using an analytical cost estimation (ACE) method. [610]. ACE takes advantage of the almost linear relationship
seen in many detailed cost analyses of the cost of electricity
(COE= Y) vs. cost of fuel (COF =X) for many technologies,
i.e.
Here Y is given is in centslkwh and X = is given in
$IMMBtu. In Eq. 5 S is the slope of the Y(X) line in
cents/kwh/$/MMBtu or 10,000 Btulkwh. S relates to the net
plant heat rate (NPHR) via
S = NPHRlIO,OOO (6) or efficiency via S
(7)
=
34.12/Eff
[6-10]. For modem coal plants S - 1. The parameter K
mainly reflects the capital cost and to a smaller extent the
operating costs of a facility as well as interest rates and rate of
return to the plant owners. Essentially K = COE if the fuel
comes to the utility without cost.
In previous studies [6-10] we found Kng = 2 is a
reasonable zero fuel cost parameter for say a 100 MW NGCC
system [34, 35]. This low number reflects the low capital
costs of the factory produced gas turbines and steam turbines
152
in NGCC systems. A slope Sng =0.7 is now reasonable
reflecting the high efficiency of recent NGCC facilities.
For a gasified solid waste combined cycle (SWCC)
system Ksw would generally be higher than Kng because the
capital costs and operating cost must include the gasifier and
gas clean-up system. The value of Ssw is also higher than Sng
because we must first make a secondary energy supply (SES)
producer gas, syngas or pyrogas which involves some
conversion losses. Ssw = 1 is a reasonable ball park slope for
an up to date SWCC system. The Xsw for a SWCC system that
would compete with a NGCC system at various Xng must
satisfY
cycle (BIGSC) system, a BIG internal combustion (BIGIC)
system a biomass -gasification-coal cofiring BIGCo system, a
direct co-firing of biomass and coal in a coal-steam boiler
BCoSt, a direct use of biomass in a feedwater heat recovery
arrangement (FWHR), direct use of biomass in a Stoker fire
boiler Steam Turbine (SFST) system and direct firing in a
combined heat and power plant (CHP) with a steam market at
$6/MMBtu. A summary of K's extracted from the AGIR was
found in a form
The Ko and KI parameters determined by regression to
the data sets in tables in the AGIR leading to very high
correlation coefficients are listed in Table 4. Subsequent
studies of other technologies and other sources confum such a
strong economy of scale forK. Values ofK extrapolated to 25,
and 100 MW are also shown. The power level dependence of
S has been somewhat more difficult to pin down. We here use
the rule
By algebra it follow that the solid waste fuel cost Xsw
that would enable a SWCC system to deliver electricity at the
same cost as a NGCC system paying Xng is given by
Xsw
=
(K ng-K,w )/Ssw + (SnglSsw)Xng (9).
In what follow all X numbers are in $/MMBtu and all Y
andK numbers are in cents/kwh. Let us use Eq. 9 with Kng =
2, Sng =0.7, Ssw = 1 and Ksw = 4 as a reasonable ball park
numbers based upon several SWCC analyses [6-10]. Then the
first term in Eq. 9 is -2. Now when the Xng= 2 to generate
SWCC electricity at the same cost the solid waste provider
must deliver the fuel at a negative price i.e. pay the tipping fee
-0.7. However, if Xng is at say 6 as it was in 2004 the SWCC
utility could pay up to 2.4 for the SW fuel. If the Xng is at 12,
the SWCC facility could pay 7.1 to the supplier. This Xsw
price is higher than that of coal whose delivered price (Xc)
these days usually is in the 2-3 range. This simple cost
comparison is illustrated in Figure 6 that shows the
opportunities for SWCC systems when natural gas prices are
above say $5IMMBtu. The results are slightly less favorable if
the Ksw were higher say at K = 5. However, the conclusions
that at high natural gas prices SWCC electricity become
competitive with NGCC electricity would be similar. It is
conceivable that K,w could be held as low as 2ct/kWh by
retrofitting a NGCC system stranded by high natural gas
prices. In this case the first term in Eq. 9 vanishes and the
competitive Xsw = (SngfSsw)Xng. This illustrates the main point
that at high natural gas prices with an ATT system SW can be
a valuable PES. Indeed, this simple algebraic-arithmetic
exercise establishes the feasibility of a New Paradigm in
which Solid Waste (mostly biomass but here meaning all
solids that are now wasted) become potentially valuable
marketable assets.
As described above the values of K and S are the key
factors in determining the COFsw to be used in a SWCC would
be competitive on a COE basis with the COE using a NGCC
system at the available COF ng. The ACE method can be
extended to the use of SW or biomass with other technologies
if we can identify the K and S for each technology. We have
previously applied the ACE method to a large body of COE vs
COF calculations on biomass use presented in an Antares
Group Inc. report (AGIR) [36]. It is reasonable to apply these
results to most of the SW listed in Table 1 particularly in small
commumhes that have recycling programs involving
residential separation of waste that would minimize the cost of
making RDF.
The technologies investigated in the AGIR when 100
tons per day forest thinning were available include a Biomass
Integrated Gasifier (BIG) CC system BIGCC, a BIG simple
where m was taken as y., in fitting the low power levels
"data" in the AGIR. However, other data sets in the literatIue
suggest a weaker S(P). Listed in Table 4 are the SI parameters
fitting the low P AGIR data and extrapolations of S to 25 and
100 MW based upon the power m = 0.1. Recognizing that low
values of K and S lead to low electricity cost, as long as the
fuel cost are reasonable, one sees that at 25 MW BCoSt (solid
fuel co-firing) and CHP are favorable as concluded in the
AGIR report for its lower power levels. However, this ACE
analysis suggests that BIGCo (gasification co-firing) and
FWHR would also be favorable for biomass at 25 MW. With a
caveat about our extrapolations to 100 MW one might
conclude that all of the technologies except BIGIC could be
competitive by virtue of their low K's. Thus the numbers
together with Eq. 5-9 suggest that that at high natural gas
prices solid waste, in the broad sense used in this paper, could
be moved from disposal costs to marketable assets with
several technologies. With some more research on evaluation
ofK's and S's for various technologies it should be possible to
use ACE as a simple tool for arriving at the best generation
candidates for a particular community in the light of the costs
of fuels in their locale.
Thus far we have focused on the competition between
NG fueled technologies and SW fueled technologies.
Competition of SW generated electricity with coal-steam
generated electricity appears to be a bigger problem. However,
if one includes the more expensive scrubber cost in the K's
and externality cost in the coal X's [37] the SWCC route
should fare well. Coal burning is now a major issue in many
communities yet when one projects technology directions
throughout the globe it is clear that the Gasification Age is
returning [38].
7. DISCUSSION
A) Biochemical Conversion
Renewables to Energy are now gammg strong
supporters in the agricultural and environmental communities
with most of this support in the US now directed towards bio153
Copyright © 2006 by ASME
C) Recycling and SWEATT
chemical conversion of biomass rather than thermo-chemical
conversion. Fermentation and anaerobic digestion are the two
major forms of bio-chemical conversion. Fermentation uses
bacteria to break down biodegradable organic material in the
absence of oxygen to produce liquid fuels such as
ethanol. Anaerobic digestion here refers to similar bacterial
processes that are designed to produce gaseous fuel products
such as methane.
Fermentation to ethanol has the most support at this time
since ethanol lends itself to conventional automotive storage
although at only 0.6 times the energy density of diesel or
gasoline. The ethanol thrust is an extension of the commercial
beer, wine and alcohol industries' processing of sugar and
starch based feedstock such as com and sugar cane. The use of
ethanol as a transportation fuel has considerable political
support although some scientists have raised questions as to
whether on balance it will help our energy import problem
[39]
Anaerobic digestion occurs in compost heaps in which
naturally occurring bacteria convert biodegradable waste to
methane gas. From the greenhouse standpoint this is a
problem since one molecule of methane is some 20 times
more damaging as a greenhouse gas than carbon dioxide. To
counter this, landfills are outfitted with collection systems and
the methane is either flared into CO2 and H20 or, in newer
landfills, harnessed as "Green Energy". Some demonstration
'landfills of the future' have added water to the waste as it
enters the landfill, to encourage anaerobic digestion of the
waste, in effect, creating an in-place bio-reactor landfill.
Unlike
conversion
biochemical
thermochemical
conversion is able to process neither the lignin (approximately
25 wt% of plant matter) nor most plastics. Another
disadvantage is that the reaction rates of all biochemical
conversion processes are vastly slower than thermo-chemical
rates. Biochemical processes usually require the 'brew' to
ferment for weeks whereas minutes or seconds are sufficient
for advanced thermal conversion (ATT). Thus the volume
required for bio-chemical processing are correspondingly
larger than for A IT processing. Another major disadvantage is
the amount of waste material and conversion by-products that
are left over once the digestion is complete much of which still
has good energy content. However, this residue can be a good
feedstock for thermo-chemical processes [II]. We have
included SW estimates from alcohol and methane production
in Table 1. By utilizing thermo-chemical processes to convert
the lignin and plastic content of and bio-chemical process
residues we might expect to get much closer to 100% energy
recycling of solid waste. SWEATT would also further reduce
the final volume of the waste and practically all contaminants
will be destroyed by the high temperatures. Co-operation
between bio-chemical and thermo-chemical programs thus
would clearly be in the national interests.
While our confrontational society has a tendency to
view waste to energy as a threat to recycling programs the
opposite might really be true. Recycling programs in a
community can serve to sort the various components or
municipal or institutional solid waste into categories that lend
themselves to maximize the return on these components. If for
example, newspaper or cardboard at a given time has no
recycling market but must be disposed of at a cost it should be
common sense to make use of the high energy content of this
dry feedstock, The same is true for plastic recycling. Thus the
market place would be decisive as to whether to recycle via
the materials route or the energy route. A recycling
community should be able to go the SWCC route with less
capital costs than one that does not have waste separation at
the source.
D) Solid Waste Alliance with Natural Gas (SWANG)
The advantages of a biomass alliance with natural gas
(BANG) have been described previously [6-10]. Gasification
systems that mainly use cellusosic (biomass) inputs produce a
low or medium heating value fuel that will result in derating
of a NG designed turbine-generator. By co-utilizing the
biomass pyrogas with natural gas one can insure that the input
energy requirement matches the output needs at least until the
maximum rating of the generator is required. At that point the
firing could be entirely on NG. In a solid waste alliance with
natural gas (SWANG) an additional option becomes available
when the solid waste comes from a recycling community.
Then the utility might prepare and store high energy plastics
for increased use during times of high electricity demand as a
means of following peak loads without calling upon the full
use of NG.
E) ATT for Liqu id Fuel Production
Pyrolysis/gasification technologies followed by gas
clean-up can greatly reduce emissions of pollutants such as
NOx and SOx and toxics such as mercury, arsenic etc. ATTs
can treat nearly the entire organic fraction of MSW and can, in
general, treat a more heterogeneous feedstock, including high
energy content plastics [11]. While this paper is focused on
gaseous fuel generation A TIs for liquid fuel production are
closely related. Considerable research and development work
are now underway on the development of distillation
technologies to refme such liquid fuels for transportation
applications adding a major driver for the ATT route.
It should be noted that Table 1 does not now list oil shale
or tar sands in the US that could substantially increase the
available "solid waste" tonnage that could be used to address
our need for transportation fuel. A 2005 Rand study [ 40 ]
shows that, with in-situ thermal treatment, domestic oil shales
could substantially lower our oil import problem. Another
route would be to convert our coal to liquid fuels, as South
Africa has done for many years. A third route would involve
the use of methane hydrates to produce methane for utilization
in natural gas fueled vehicles.
B) Solid Waste from Bio-Oils
The esters of vegetable oils are renewable alternative
fuels that can potentially serve as direct replacements for
diesel fuels in compressed ignition engines (CIE). Oils from
soybeans, sunflower seeds, safflower, cottonseeds, peanuts,
and rapeseeds as well as used oil from restaurants are under
considerable investigation as replacements for diesel. Waste
from bio-oil programs have been included in Table 1 since
only the seeds of the plants are used for bio-oil crops and the
rest of the plant becomes solid waste amenable to serve as an
input of a SWEATT program.
Copyright © 2006 by ASME
F) Sustainability and SWEATT
Japan a country with an outstanding Sustainability record
is now the global leader in the conversion of solid waste to
energy by advanced thermal technologies (SWEATT). The
more than 60 pyrolysis and thermal gasification systems now
in operation in Japan have established the technical and
environmental feasibility of these systems which should allay
154
[4] Green, A., 2002, "A Green Alliance of Biomass and Coal
(GABC)," Appendix F, National Coal Council report
May 2002: Proc. 27th Clearwater Conference, March
2003.
[5] Green, A., Hughes, E., (EPRl) andKandiyoti, R.,
(Imperial College London) conference organizers,
(2004), Proceedings of the First International
Conference on Co-utilization of Domestic Fuels, Vol
24, 3, the International Journal of Power and Energy
Systems.
[6] Green A.and J Feng , (2003) A Green Alliance of Biomass
and Natural Gas for a Utility Services Total Emission
Reduction (GANGBUSTER), Final report to School
of Natural Resources and the Environment.
[7] A. Green, W. Smith, A Hermansen-Baez, A Hodges, 1.
Feng, D. Rockwood, M. Langholtz, F. Najafi and U.
Toros, Multidisciplinary Academic Demonstration of
a Biomass Alliance with Natural Gas (MADBANG)
(2004) Proceedings of the International Conference
on Engineering Education, University of Florida,
Conference Center, Gainesville, Florida October
[8] Green A.,Klausner J, Li Yi A Green Alliance of Natural
Gas, Biomass and Utility Desalination Proc 29th
Intern. Conf. on Coal Technology, Clearwater
Florida, April 2004
[9] Green A., Swansong G. and Najafi F.(2004) Co-utilization
of Domestic Fuels Biomass GaslNatural Gas,
GT2004-54194, IGTI meeting in Vienna June 14-17.
[10] Green A.and J Feng , (2005) Assessment of
Technologies for Biomass Conversion to Electricity
at the Wildland Urban Interface Proceedings of
ASME Turbo Expo 2005: Reno-Tahoe
[11] California Integrated Waste Management Board, (2005)
Conversion Technologies Report to the Legislature,
Draft,
http://www.ciwmb.ca.gov/Organics/ConversioniEven
tsl
[12] Energy Information Administration, (2006) January 2006
Monthly Energy Review , Office of Energy Markets
and End Use,U.S. Department of Energy, DOE/EIA0035(2006/01), Washington D.C.,
http://www.eia.doe.gov/emeuimer/contents.htrnl
[13] Perlack, R., Stokes, B., Erbach, D., (2005) Biomass as
Feedstock for a Bioenergy and Bioproducts Industry:
The Technical Feasibility of a Billion-Ton Annual
Supply, Oak Ridge National Laboratory, ORNLlTM2005166, U.S. Dept. of Energy
[14] Stultz, S.,Kitto, 1., ed., (1992), Babcock & Wilcox,
Steam 40th Edition, Barberton, OH, Chapter 37
Equipment Specification, Economics and Evaluation.
[15] A. Green, S. Peres, J. Mullin, and H. Xue, Co-gasification
of Domestic Fuels, Proc.lJPGc. Minneapolis MN,
ASME-NY, NY(1996).
[16] A. Green, M. Zanardi, J. Mullin, Biomass & Bioenergy,
13(1997) 15-24.
[17] A. Green, M. Zanardi, Inti Jour. Quantum Chemistry, 66
(1998) 219-227.
[18] A. Green, J. Mullin, Journal of Engineering for Gas
Turbines and Power, 121 (1999) 1-7.
[19] A. Green, J. Mullin, G. Schaefer, N.A, Chancy, W. Zhang,
Life support applications of TCM-FC Technology,
31st ICES Conference, Orlando, FL, July, 2001.
[20] A. Green, P. Venkatachalam, M.S. Sankar, Feedstock
Blending of Domestic Fuels in Gasifier/Liquifiers,
TURBO EXPO 2001, Amsterdam, GT,- 2001.
the concerns of environmentalists and risk-averse utility
decision makers
8. CONCLUSIONS
The main conclusion of this paper is that the US has very
large sustainable supplies of now wasted solids that have an
annual energy potential comparable to our current use of coal
and also of natural gas. With advanced thermal technologies
(ATT) this solid waste could, in the near term, multiply its
contribution to our national energy supply by about a factor of
10. Robust technology that can handle municipal solid waste
(MSW) or refuse derived fuel (RDF) should also be able to
handle agricultural and forestry residues, two of the major SW
supply components listed in Table I as well as many of the
other materials in the list. Conservation and SWEATT could
be the only realistic path to Zero Waste.
Recapitulating the main conclusions of this study are:
• The U.S. is excessively reliant on imported oil (60% ) for
its liquid fuels
• The US is increasingly reliant on imported natural gas fuel
(now >15%).
• The U.S. is well endowed with solid fuels: wasted solids,
coal and oil shale.
• The organic matter in SW can be converted into more
useful gaseous or liquid fuels
• In most cases ATT provides the fastest and most efficient
conversion method.
• SWEATT have lower emissions than combustion waste to
energy systems.
• Thermal conversion of solid fuels to gaseous and liquids
fuels has a long history
• Utilities are used to high temperatures in the production of
steam.
• ATTs (PABC, POBC and PYRO) are extensions of high
temperature steam making.
• Conversion to gaseous fuels is essential for SW powering
of fuel cells.
• There
are many environmental benefits attendant to
SWEATT.
• Many areas of engineering research will be needed to
optimize SWEATT.
• Co-operation
of stakeholders would accelerate the
implementation of ATT.
• Conservation and SWEATT together is the fastest realistic
path to Zero Waste.
9. ACKNOWLEDGEMENT
This work was supported by Green Liquids and Gas
Technologies Inc.
10. REFERENCES
(1] Green, A., ed. (1981), An Alternative to Oil, Burning Coal
with Gas, Univ. Presses of Florida, Gainesville FL.
[2] Green, A., et aI., (1986), "Coal-Water-Gas, An All
American Fuel for Oil Boilers," Proc. of the Eleventh
Intern. Conf. on Slurry Technology, Hilton Head, Sc.
[3] Green, A., ed. ., (1991), "Solid Fuel Conversion for the
Transportation Sector" FACT-Vol 12 ASME New
York NY. Proc. of special session at International
Joint Power Generation Conference San Diego
155
Copyright © 2006 by ASME
[21] A. Green, R. Chaube, Pyrolysis Systematics for Co­
utilization Applications. TURBO EXPO 2003, June
2003. Atlanta, GA, 2003.
[22] A. Green, R. A Chaube, IntI. Jour. Power and Energy
Systems, 24(3) (2004) 215-223.
[23] A. Green, S. M. Sadrameli, "Analytical Represntations of
experimental polyethylene Pyrolysis yields", Jour. of
Analytical and Applied Pyrolysis, 72 (2004) 329-335.
[24] S. Sadrameli, A. Green, Jour. of Analytical and Applied
Pyrolysis, 73,(2005) 305-313.
[25] Green, A., Feng, J., (2006), Systematics of Com Stover
Pyrolysis Yields and Comparisons of Analytical and
Kinetic
[26] Feng, 1., Green, A., (2006) Peat Pyrolysis and the
Analytical Semi-emperical Model, 1. Energy Sources,
(in press), ESO/051103.
[27] Feng, J., YuHong, Q., Green, A., (2006), Analytical
Model of Com Cob Pyroprobe-FTIR Data, J.
Biomass and Bioenergy, (in press).
[28] Gaur, S., Reed, T., 1998, Thermal Data/or Natural and
Synthetic Fuels, Marcel Dekker, New York, NY
[30] Xu, W. C., and Tomita, A., (1987), Effects of temperature
on the flash Pyrolysis of various coals, Fuel, Vol. 66.
pp. 632-636.
[31] Xu, W. C., and Tomita, A., (1987) Effects of coal type on
the flash pyrolysis of various coals, Fuel, Vol. 66, pp.
627-631.
[32] Mastral, F. 1., Esperanza, E., Garcia, P., Juste, M.,(2002)
,J. Anal. Appl. Pyrolysis, Vol. 63, pp. 1-15.
[33] Mastral, F. J., Esperanza, E., Berruco, C., Juste, M.,
(2003), 1. Analy. Appl. Pyrolysis, Vol. 70, pp. 1-17,
[34] Liscinsky, D., Robson, R., Foyt, A., Sangiovanni, J.,
Tuthill, R., and Swanson, M., (2003), Advanced
Technology Biomass-Fueled Combined Cycle, Proc.
ASME Turbo Expo 2003, Power for Land, Sea and
Air, Atlanta, GA, USA, GT2003-38295,
[35] Phillips, B., and Hassett, S., (2003), Technical and
Economic Evaluation of a 79 MWe (Emery) Biomass
IGCC, Gasification Technologies Conf., San
Francisco, CA,
[36] Antares Group, Inc., (2003), Assessment of Power
Production at Rural Utilities Using Forest Thinnings
and Commercially Available Biomass Power
Technologies. Landover, MD, Sept.
[37] Ian F. Roth, Lawrence L. Ambs (2004), Incorporation
externalities into a full cost approach to electric
power generation life-cycle costing, Energy Vol29
12-15 P2125-2144
[38] Rosenberg, W., Walker, M., and Alpern, D, 2005, .
"National Gas Strategy", a publication of the
Kennedy School of Government, Harvard University,
Cambridge MA.
[39] Pimentel, D., and Patzek, T. W., (2005), J. Natural
Resources Research, Vol. 14:1, pp. 65-76.
[40] Bartis, 1., LaTourrette, T., et aI., (2005) Oil shale
development in the United States: prospects and
policy issues, RAND corp. ISE division, National
Energy Technology Laboratory, US DoE, Pittsburgh,
PA
Copyright © 2006 by ASME
156
NOMENCLATURE
WEC
SW
ASEM
Waste to Energy Conversion
Solid Waste
Analytical Semi-Empirical Model
SWEATT
Solid Waste To Energy By Advanced Thermal
.
Technologies
ATT
DANSF
ACE
Advanced Thermal Technologies
Dry Ash, N itrogen And Sulfur Free
Analytical Cost Estimation
HRSG
NGCC
CHP
ABPC
OBPC
European Union
Total Primary Energy Supply
British Thermal Units
Quadrillion BTUs
Omnivorous Feedstock Converter
Clean Combustion Technologies Laboratory
Secondary Energy Supplies
Primary Energy Supplies
Tertiary Energy Supply
Quaternary Energy Supply
Municipal Solid Waste
Internal Combustion Engines
Gas Turbines
Heat Recovery Steam Generator
Natural Gas-Fired Combined Cycle
Combined Heat And Power
Air Blown Partial Combustion
Oxygen Blown Partial Combustion
PYRO
RDF
PNA
Ar
VT
FC
HHV
XT
NPHR
SWCC
AGIR
BIG
CC
IC
Co
CoSt
FWHR
SFST
Pyrolysis Systems
Refuse Derived Fuels
Polynuclear Aromatics
Aromatics
Volatiles
Fixed Carbon
Higher Heating Values
Xu and Tomita
Net Plant Heat Rate
Solid Waste Combined Cycle
Antares Group Inc. Report
Biomass Integrated Gasifier
Combined Cycle
Internal Combustion
Cofiring
Coal-Steam Boiler
Feedwater Heat Recovery
Stoker Fire Boiler Steam Turbine
CIE
SWANG
Compressed Ignition Engines
Solid Waste Alliance with Natural Gas
EU
TPES
BTU
quads
OFC
CCTL
SES
PES
TES
QES
MSW
ICE
GT
Waste
Million Dry
Tons
Type
1 . Agricultural residues
-0.98
2. Forest under-story and forestry residues
-0.40
3 . Hurricane debris
-0.04
4 . Construction and deconstruction debris
-0.02
5 . Refuse derived fuels
-0. 1 0
6 . Urban yard waste
-0.02
7. Food serving and food processing waste
-0 .0 7
8. Used newspaper and paper towels
-0.02
9. Used tires
-0.05
1 0. Energy crops on under-utilized lands
-0.05
1 1 . Ethanol production waste
-0.02
1 2 . Anaerobic digestion waste
-0 Q l
1 3 . Bio-oil production waste
-0.0 1
1 4 . Waste plastics
-0.03
1 5 .Infested trees, (beetles, canker, spores)
-0.02
1 6 . Invasive species (cogon-grass, melaluca..)
-0.0 2
1 7. Plastics mined when restoring landfills
1 8 . *Bio-solids (dried pelletized sewage
sludge)
-0.03
1 9. *Poultry and pig farm waste
-0.02
20. *Water plant-remediators (algae, hydrilla..)
-0. 0 1
2 1 . *Muck pumped to shore to remediate lakes
-0.0 1
22. Manure from cattle feed lots
-0.0 1
2 3 . Plants for phyto-remediation of toxic sites
-0. 0 1
.
24 . Treated wood p_ast its useful life
-0.04
-0.01
- 2 billion
TOTAL
dry tons
TABLE 1 : WASTED SOLI DS THAT COU LD BE USED AS
A COMPONENT OF U.S.'S PRI MARY EN ERGY SUPPLY.
ITEMS MARKED WITH · HELP I N WATER REMEDIATION
AND THE - DENOTES ESTIMATED VALU ES
1 57
Copyright © 2006 by ASME
Table 2 A : Proximate and U ltimate Analyses
U ltimate Analysis
Proximate A nalysis
Name
%VM
%Liq
FC
Ash
C%
H%
0%
Bagasse
Elephant grass
Pine bark
Bond paper
Newsprint
Coal
Wood pellets
Polyolefin
PETG
Tire rubber
59.2
72
55
6 1 .93
56.66
22.02
61.34
56.58
5 1 .8
2 1 .96
9.8
0.35
1 0.5
18.7
25.5
1 3.6
23. 1
42.4
43.7
35.6
20
19
34
8.4
1 5.4
57.2
15
1
4.5
35.8
11
8.65
0.5
11
2.4
7.2
0.5
0
0
6.6
45.7 1
44.58
56.3
41.2
49. 1 4
76.9
47.84
85.7
62.5
79.1
5.89
5.35
5.6
5.5
6. 1
5.1
5.8
14.3
4.2
6.8
40.37
39. 1 8
37.7
4 1 .9
43.03
6.9
45.76
0
33.3
5.9
N ame
R2
CO
CH4
CO2
C2H2
C2H4
C2H6
Bagasse
Elephant grass
Pine bark
Bond paper
Newsprint
Coal
Wood pellets
Polyolefin
PETG
Tire rubber
1 .26
1 .48
1 .62
1.56
1 .3
1 .26
1 .37
l.l7
0.64
1 .32
28.92
3 1 .84
29.58
27.4 1
29.25
8.74
33.29
4.72
15.52
2.07
5.75
7.64
5.38
5.59
5.93
6.48
6.52
16.09
4.63
1 1 .26
1 8.66
24.66
1 5.22
23.42
16. 1 9
3.48
1 5.96
6.0 1
29.06
1 .33
0.32
0.38
0.37
0.36
0.6
0. 1 9
0.5 1
0.76
0.2
0.61
3.72
5. 1
2.56
3.34
3.24
1 .63
3.44
25.39
1.7
4.97
0.37
0.65
0. 1 2
0.25
0. 1 5
0.22
0.25
2.44
0.06
0.4
Table 2 B : Mass Percentages at
t OOO°C
TABLE 2 : CCTL MEASURED PROXIMATE, U LTIMATE, AND MASS YI ELDS OF SOLID WASTE AT 1 000oC, ADAPTED FROM
[1 7].
Copyright © 2006 by ASME
1 58
Fami lies
paraffins
a
b
c
J
2a+2
0
2a
0
0
0
0
j+ 1
j+ 1
5+j
6+4j
j+ 1
j
olefins
acetylenes
aromatics
polynuclear
aldehydes
carbonyls
alcohols
ethers
phenols
formic acids
guaiacols
syringols 1
syringols 2
sugars 1
sugars 2
2a-2
4+2j
6+2j
2a
2a
1
j
j+ l
5+j
2a+2
2a+2
4+2j
1
1
1
j
2a
2
6+2i
8+2j
1 O+2j
10
1 0+2j
2
6+i
7+j
8+j
4+j
5+j
I
3
4
5
5
TABLE 3: ORGAN IZATION OF FU NCTIONAL GROUPS
BY FAMILY. A, B, AND C ARE THE SUBSCRIPTS IN
CAHBOc, WHERE J=1 , 2, 3 . . .
AGIR
Technology
BIG CCsyn
COE
=
Ko +K/p I
/2
+ S] COF /p
Centslkwh
Cents/kwh
BTUlkwh
-2.82
K]
45.2
SI
3.5 1
Ko
1i4
25 MW
1 00 MW
MW
P (MW)
Cents/kwh
K
BTU/kwh
S
Cents/kwh
K
BTU/kwh
S
1 0, 15, 25
6.22
1 . 66
1 . 70
1 .44
0.33
34. 1
2.06
2, 1 0, 15
7. 1 5
1 . 08
3 . 74
0.94
BIG ICsyn
3 .74
1 6.4
2.06
2, 1 0, 15
7.02
1 . 08
5 . 38
0.94
Solid Fuel
Co firing
1 .27
1 .9
2. 1 7
2 , 10, 1 5
1 .65
1 .14
1 .46
0 .99
BIG SCSyn
Gasification
Cofiring
2.02
7. 1
2.34
2, 1 0, 15
3.44
1 . 23
2 . 73
1 . 07
FWHR
0.29
-4.44
-26.6
1 0.7
2.38
3 . 1 3 .20
2 .43
1 .2 0
1 . 36
1 . 04
39. 1
48
4.5
7.41
0.7, 1 0, 1 5
0.5, 4, 6
3 . 38
2.39
-0.53
2.08
- 1 7.00
4.50
-2 1 . 80
3 . 92
SBST
CHP
TABLE 4: ACE PARAMETERS FOR VARIOUS TECHNOLOGIES, WHERE COST OF ENERGY (COE) IS M EASU RED IN
CENTS/KWH AND THE COST OF FUEL (COF) IS MEASURED I N $/MMBTU. THE K AND S PARAMETERS EXTRAPOLATED
TO THE 25 AND 1 00 MW POWER LEVELS (P) ARE SHOWN. ADAPTED FROM [ ].
1 59
Copyright © 2006 by ASME
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Rfu!e [shed FUel (REf)
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Crenicas
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rl
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Activated Corboll
Coke, Astl
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FIGURE 1 : DIAGRAM OF THE OMN IVOROUS FEEDSTOCK CONVERTER (OFC) ILLUSTRATING THE ADDITION OF A SOLID
WASTE SYSTEM TO AN EXISTING NGCC PLANT TO CREATE AN EFFECTIVE SWCC SYSTEM.
Copyright © 2006 by ASME
1 60
U SA Energy Consumption
Renewables
3
2.5
�
n
Biomass -
2
1 .5
Solid Waste
�
2.8
-
Hydroelectric
2.8
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r0.5
o
2005
r-
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0.35
-
n
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l
Wind Energy
0 14
r""l
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solar Energy
0.06
FIGURE 2: (LEFT) TOTAL 2005 ANNUAL USA ENERGY CONSU M PTION OF PRIMARY ENERGY SOURCES IN QUADS
(RIGHT) RENEWABLES. NOTE: DATA FROM NOVEMBER AND DECEMBER 2005 WAS ESTIMATED FROM 2004 DATA.
161
Copyright © 2006 by ASME
o
1 0
PS
8
30
20
60
50
40
T-----T-�--;_--�--��
PU
1 0
F o o d W a s te
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F IGURE 3A: WEIGHT PERCENTAGES OF HYDROGEN [H] VS [0] FOR 1 85 DANSF CARBONACEOUS MATERIALS (BLACK
D IAMONDS) VS OXYGEN WT%. CLASSIFICATION LABELS ARE GIVEN AT THE BOTTOM SCALE AND [0] VALUES ON TOP
SCALE. ADAPTED FROM [4].
40 �--
-----,------.-------�----�
--,
·
__
35 +- .����-----r--�--�
30 +--- . .��--���----1_------�----�
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n
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o
20
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30
40
50 )
F IGURE 3C: TOTAL VOLATILE WEIGHT PERCENTAGES
VS [0] FOR 1 85 DAS N F CARBONACEOUS MATERIALS
(SQUARES) FROM PROXI MATE ANALYSIS. THE CURVE
THROUGH THE DATA POINTS SATISFIES
VT =62([H]/6)([O]/25) 1/2 . THE ANALYTIC F IXED CARBON
(FC) IS SHOWN.
FIGURE 38: H I G H E R HEAT I N G VALUES (HHV) OF 1 85
CARBONACEOUS MATERIALS (CORRECTED TO
DANSF) VS. [0]. THE S MOOTH CURVE REPRESENTS
H HV= A([C]/3+[H]-[O]/8)
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1 62
A n th
ra e
B it u m i n o u s
ita ( 9 4 . 3 , 3 )
,J...._--1 C .. .
CO
He
_...j..---"'t C H "
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10 +-��--+---����----+-------4_��
=:.::.--t..L--- ----tjii·O
�oo
fOO
1 000
12:00
FIGURE 4: WT. % YIELDS VS. TEMPERATURE (IN 0c) FROM PYROLYSIS OF ANTHRACITE, BITUMINOUS, LIGNITE, AND
WOOD WITH ([C], [H], [OJ) AS SHOWN. HC REPRESENTS C2 AND C3 GASSES, BTX, PHENOL AND CRESOL. ADAPTED
FROM [ ].
1 63
Copyright © 2006 by ASME
1 00 �---��-
75
50
25
o
400
600
800
1 000
6000
FIGURE 5: Y I E LDS VS. TEMPERATURE FOR POLYETHYLENE IN VARIOUS HYDROCARBON GROUPS. ADAPTED FROM
COE vs COF
.:::
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r---- --�����-+-----jf--j
o
o
r-�������---'---1--�--�
.5
w
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o
2
4
6
8
10
12
COF in $IMMBtu
FIGURE 6 : COE VS. COF FOR SWCC AND NGCC AT
XNG= 2, 6, 1 2 . ADAPTE D FROM [ ).
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1 64
[ ].
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