U.S. patent application number 10/297938 was filed with the patent office on 2003-06-05 for fuel for use in a fuel cell system.
Invention is credited to Anzai, Iwao, Matsubara, Michiro, Sadakane, Osamu, Saitou, Kenichirou.
Application Number | 20030105369 10/297938 |
Document ID | / |
Family ID | 26594999 |
Filed Date | 2003-06-05 |
United States Patent
Application |
20030105369 |
Kind Code |
A1 |
Saitou, Kenichirou ; et
al. |
June 5, 2003 |
Fuel for use in a fuel cell system
Abstract
A fuel for a fuel cell system comprises wherein said fuel
comprises hydrocarbons comprising 60 mol. % or more of saturates,
40 mol. % or less of olefins, 0.5 mol. % or less of butadiene, 0.1
mol. % or more of isoparaffin in saturates having carbon atoms of 4
or more and being a gaseous phase under normal temperature and
pressure. The fuel for a fuel cell system has a high power
generation quantity per weight, a high power generation quantity
per CO.sub.2 emission, a low fuel consumption, a small evaporative
gas (evapo-emission), small deterioration of a fuel cell system
comprising such as a reforming catalyst, a water gas shift reaction
catalyst, a carbon monoxide removal catalyst, fuel cell stacks and
the like to maintain the initial performances for a long duration,
good handling properties in view of storage stability and
inflammability, and a low preheating heat quantity.
Inventors: |
Saitou, Kenichirou;
(Kanagawa, JP) ; Anzai, Iwao; (Kanagawa, JP)
; Sadakane, Osamu; (Kanagawa, JP) ; Matsubara,
Michiro; (Kanagawa, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
26594999 |
Appl. No.: |
10/297938 |
Filed: |
December 20, 2002 |
PCT Filed: |
June 29, 2001 |
PCT NO: |
PCT/JP01/05645 |
Current U.S.
Class: |
585/6 ;
585/14 |
Current CPC
Class: |
C01B 2203/1205 20130101;
Y02E 60/50 20130101; C01B 2203/0283 20130101; C01B 2203/085
20130101; C01B 2203/1064 20130101; C01B 2203/066 20130101; C01B
2203/0233 20130101; C01B 2203/047 20130101; C01B 2203/1235
20130101; C10L 3/00 20130101; C01B 3/583 20130101; C01B 2203/1652
20130101; C01B 3/48 20130101; C01B 2203/1288 20130101; C01B
2203/0261 20130101; C01B 3/38 20130101; C01B 2203/044 20130101;
H01M 8/0612 20130101 |
Class at
Publication: |
585/6 ;
585/14 |
International
Class: |
C10L 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 29, 2000 |
JP |
2000-196649 |
Jun 29, 2000 |
JP |
2000-196651 |
Claims
1. A fuel for use in a fuel cell system, wherein said fuel
comprises 60 mol. % or more of saturates, 40 mol. % or less of
olefins, 0.5 mol. % or less of butadiene, 0.1 mol. % or more of
isoparaffin in saturates having carbon atoms of 4 or more, and is a
gaseous phase under normal temperature and pressure.
2. A fuel according to claim 1, wherein a sulfur content is 50 ppm
by mass or less.
3. A fuel according to claim 1, wherein a content of hydrocarbons
having carbon numbers of 2 or less is 5 mol. % or less, a content
of hydrocarbons having carbon numbers of 3 and 4 in total is 90
mol. % or more and a content of hydrocarbons having carbon numbers
of 5 or more is 5 mol. % or less.
4. A fuel according to claim 2, wherein a content of hydrocarbons
having carbon numbers of 2 or less is 5 mol. % or less, a content
of hydrocarbons having carbon numbers of 3 and 4 in total is 90
mol. % or more and a content of hydrocarbons having carbon numbers
of 5 or more is 5 mol. % or less.
5. A fuel according to claim 4, wherein vapor pressure at
40.degree. C. is 1.55 MPa or less.
6. A fuel according to claim 4, wherein density at 15.degree. C. is
0.500 to 0.620 g/cm.sup.3.
7. A fuel according to claim 6, wherein vapor pressure at
40.degree. C. is 1.55 MPa or less.
8. A fuel according to claim 4, wherein corrosiveness to copper at
40.degree. C. for 1 hour is 1 or less.
9. A fuel according to claim 5, wherein corrosiveness to copper at
40.degree. C. for 1 hour is 1 or less.
10. A fuel according to claim 6, wherein corrosiveness to copper at
40.degree. C. for 1 hour is 1 or less.
11. A fuel according to claim 7, wherein corrosiveness to copper at
40.degree. C. for 1 hour is 1 or less.
12. A fuel according to claim 4, wherein heat capacity of the fuel
is 1.7 kJ/kg .degree. C. or less at 15.degree. C. in gaseous
phase.
13. A fuel according to claim 7, wherein heat capacity of the fuel
is 1.7 kJ/kg .degree. C. or less at 15.degree. C. in gaseous
phase.
14. A fuel according to claim 9, wherein heat capacity of the fuel
is 1.7 kJ/kg .degree. C. or less at 15.degree. C. in gaseous
phase.
15. A fuel according to claim 10, wherein heat capacity of the fuel
is 1.7 kJ/kg .degree. C. or less at 15.degree. C. in gaseous
phase.
16. A fuel according to claim 11, wherein heat capacity of the fuel
is 1.7 kJ/kg .degree. C. or less at 15.degree. C. in gaseous phase.
Description
TECHNICAL FIELD
[0001] The present invention relates to a fuel to be used for a
fuel cell system.
BACKGROUND ART
[0002] Recently, with increasing awareness of the critical
situation of future global environments, it has been highly
expected to develop an energy supply system harmless to the global
environments. Especially urgently required are to reduce CO.sub.2
to prevent global warming and reduce harmful emissions such as THC
(unreacted hydrocarbons in an exhaust gas), NO.sub.X, PM
(particulate matter in an exhaust gas: soot, unburned high boiling
point and high molecular weight fuel and lubricating oil).
Practical examples of such a system are an automotive power system
to replace a conventional Otto/Diesel engine and a power generation
system to replace thermal power generation.
[0003] Hence, a fuel cell, which has high energy efficiency and
emits only H.sub.2O and CO.sub.2, has been regarded as a most
expectative system to response to respond to social requests. In
order to achieve such a system, it is necessary to develop not only
the hardware but also the optimum fuel.
[0004] Conventionally, as a fuel for a fuel cell system, hydrogen,
methanol, and hydrocarbons have been candidates.
[0005] As a fuel for a fuel cell system, there is methanol except
for hydrogen. Methanol is advantageous in a point that it is
relatively easy to reform, however power generation quantity per
weight is low and owing to its toxicity, handling has to be
careful. Further, it has a corrosive property, special facilities
are required for its storage and supply.
[0006] Like this, a fuel to sufficiently utilize the performances
of a fuel cell system has not yet been developed. Especially, as a
fuel for a fuel cell system, the following are required: power
generation quantity per weight is high; power generation quantity
per CO.sub.2 emission is high; a fuel consumption is low in a fuel
cell system as a whole; an evaporative gas (evapo-emission) is a
little; deterioration of a fuel cell system comprising such as a
reforming catalyst, a water gas shift reaction catalyst, a carbon
monoxide conversion catalyst, fuel cell stacks and the like is
scarce to keep the initial performances for a long duration; a
starting time for the system is short; and storage stability and
handling easiness are excellent.
[0007] Incidentally, in a fuel cell system, it is required to keep
a fuel and a reforming catalyst at a proper temperature, the net
power generation quantity of the entire fuel cell system is
equivalent to the value calculated by subtracting the energy
necessary for keeping the temperature (the energy for keeping
balance endothermic and exothermic reaction following the
preheating energy) from the actual power generation quantity.
Consequently, if the temperature for the reforming is lower, the
energy for preheating is low and that is therefore advantageous and
further the system starting time is advantageously shortened. In
addition, it is also necessary that the energy for preheating per
fuel weight is low. If the preheating is insufficient, unreacted
hydrocarbon (THC) in an exhaust gas increases and it results in not
only decrease of the power generation quantity per weight but also
possibility of becoming causes of air pollution. To say conversely,
when some kind of fuels are reformed by the same reformer and the
same temperature, it is more advantageous that THC in an exhaust
gas is lower and the conversion efficiency to hydrogen is
higher.
[0008] The present invention, taking such situation into
consideration, aims to provide a fuel suitable for a fuel cell
system satisfying the above-described requirements in good
balance.
DISCLOSURE OF THE INVENTION
[0009] Inventors of the present invention have extensively
investigated to solve the above-described problems and found that a
fuel comprising hydrocarbons with specific compositions is suitable
for a fuel cell system.
[0010] That is, the fuel for a fuel cell system according to the
present invention comprises:
[0011] (1) hydrocarbons comprising 60 mol. % or more of saturates,
40 mol. % or less of olefins, 0.5 mol. % or less of butadiene, 0.1
mol. % or more of isoparaffin in saturates having carbon atoms of 4
or more and being a gaseous phase under normal temperature and
pressure.
[0012] The fuel comprising hydrocarbons with the above-described
compositions is preferable to satisfy the following additional
requirements;
[0013] (2) a sulfur content is 50 ppm by mass or less;
[0014] (3) a content of hydrocarbons having carbon numbers of 2 or
less is 5 mol. % or less, a content of hydrocarbons having carbon
numbers of 3 and 4 in total is 90 mol. % or more, a content of
hydrocarbons having carbon numbers of 5 or more is 5 mol. % or
less;
[0015] (4) vapor pressure at 40.degree. C. is 1.55 MPa or less;
[0016] (5) density at 15.degree. C. is 0.500 to 0.620
g/cm.sup.3;
[0017] (6) corrosiveness to copper at 40.degree. C. for 1 hour is 1
or less;
[0018] (7) heat capacity of the fuel is 1.7 kJ/kg.degree. C. or
less at 15.degree. C. in gaseous phase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows a flow chart of a steam reforming type fuel
cell system employed for evaluation of a fuel for a fuel cell
system of the invention.
[0020] FIG. 2 is a flow chart of a partial oxidation type fuel cell
system employed for evaluation of a fuel for a fuel cell system of
the invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021] Hereinafter, the contents of the invention will be described
further in detail.
[0022] In the present invention, the hydrocarbons with specific
compositions are ones comprising 60 mol. % or more of saturates
(M(S)), 40 mol. % or less of olefins (M(O)), 0.5 mol. % or less of
butadiene (M(B)), 0.1 mol. % or more of isoparaffin (M(IP)) in
saturates having carbon atoms of 4 or more, and are a gaseous phase
under normal temperature and pressure.
[0023] The saturates (M(S)) is 60 mol. % or more, preferably 80
mol. % or more, more preferably 95 mol. % or more and most
preferably 99 mol. % or more in view of a high power generation
quantity per weight, a high power generation quantity per CO.sub.2
emission, a low fuel consumption of a fuel cell system as a whole,
a low THC in an exhaust gas, short starting time of a system, and
the like.
[0024] The olefins (M(O)) is 40 mol. % or less, preferably 10 mol.
% or less and most preferably 1 mol. % or less in view of a high
power generation quantity per weight, a high power generation
quantity per CO.sub.2 emission, a low fuel consumption of a fuel
cell system as a whole, a low THC in an exhaust gas, short starting
time of a system, small deterioration of a reforming catalyst to
maintain the initial performances for a long duration, a good
storage stability, and the like.
[0025] The butadiene (M(B)) is 0.5 mol. % or less and preferably
0.1 mol. % or less in view of a high power generation quantity per
weight, a high power generation quantity per CO.sub.2 emission, a
low fuel consumption of a fuel cell system as a whole, a low THC in
an exhaust gas, short starting time of a system, small
deterioration of a reforming catalyst to maintain the initial
performances for a long duration, a good storage stability, and the
like.
[0026] The isoparaffin (M(IP)) in saturates having carbon atoms of
4 or more is 0.1 mol. % or more, preferably 1 mol. % or more, more
preferably 10 mol. % or more, furthermore preferably 20 mol. % or
more and most preferably 30 mol. % or more in view of a low fuel
consumption of a fuel cell system as a whole, a low THC in an
exhaust gas, short starting time of a system, and the like.
[0027] Incidentally, the above-described (M(S)), (M(O)), (M(B)) and
(M(IP)) are values measured by JIS K 2240, "Liquefied Petroleum
Gases 5.9 Methods for Chemical Composition Analysis".
[0028] Further, the content of sulfur in a fuel of the invention is
not particularly restricted, however, because deterioration of a
fuel cell system comprising such as a reforming catalyst, a water
gas shift reaction catalyst, a carbon monoxide removal catalyst,
fuel cell stacks, and the like can be suppressed to low and the
initial performances can be maintained for a long duration, the
content is preferably 50 ppm by mass or less, more preferably 10
ppm by mass or less, further more preferably 1 ppm by mass or
less.
[0029] Then, it is most preferably to satisfy the above-described
preferable ranges of sulfur and the above-described preferable
ranges of compositions since deterioration of a fuel cell system
comprising such as a reforming catalyst, a water gas shift reaction
catalyst, a carbon monoxide removal catalyst, fuel cell stacks, and
the like can be suppressed to low and the initial performances can
be maintained for a long duration.
[0030] Here, sulfur content means that measured by JIS K 2240,
"Liquefied Petroleum Gases 5.5 or 5.6 Determination of sulfur
content".
[0031] In the fuel according to the invention, compositions of
respective carbon atoms are not particularly restricted, however,
it is preferable that a content of hydrocarbons having carbon
numbers of 2 or less is 5 mol. % or less, a content of hydrocarbons
having carbon numbers of 3 and 4 in total is 90 mol. % or more, and
a content of hydrocarbons having carbon numbers of 5 or more is 5
mol. % or less.
[0032] The content of hydrocarbons having carbon numbers of 2 or
less is preferably 5 mol. % or less and more preferably 3 mol. % or
less in relation to the storage, inflammability and evapo-emission
and the like. The content of hydrocarbons having carbon numbers of
3 and 4 in total is 90 mol. % or more and more preferably 95 mol. %
or more in view of a high power generation quantity per weight, a
high power generation quantity per CO.sub.2 emission, a low fuel
consumption of a fuel cell system as a whole, a low THC in an
exhaust gas, short starting time of a system, small deterioration
of a reforming catalyst to maintain the initial performances for a
long duration, and the like. The content of hydrocarbons having
carbon numbers of 5 or more is 5 mol. % or less and more preferably
2 mol. % or less in view of a high power generation quantity per
weight, a high power generation quantity per CO.sub.2 emission, a
low fuel consumption of a fuel cell system as a whole, a low THC in
an exhaust gas, short starting time of a system, small
deterioration of a reforming catalyst to maintain the initial
performances for a long duration, and the like.
[0033] Incidentally, the compositions of respective carbon atoms
mentioned above are values measured by JIS K 2240, "Liquefied
Petroleum Gases 5.9 Methods for Chemical Composition Analysis".
[0034] Further, vapor pressure of a fuel of the invention is not
particularly restricted, however, it is preferably 1.55 MPa or less
and more preferably 1.53 MPa or less at 40.degree. C. in relation
to the storage, inflammability and evapo-emission and the like.
[0035] Incidentally, the vapor pressure at 40.degree. C. is
measured by JIS K 2240, "Liquefied Petroleum Gases 5.4 Calculation
method for density and vapor pressure".
[0036] Further, density of a fuel of the invention is not
particularly restricted, however, it is preferably 0.620 g/cm.sup.3
or less at 15.degree. C. in view of a high power generation
quantity per weight, a high power generation quantity per CO.sub.2
emission, a low fuel consumption of a fuel cell system as a whole,
a low THC in an exhaust gas, short starting time of a system, small
deterioration of a reforming catalyst to maintain the initial
performances for a long duration, and the like, and more preferably
0.500 g/cm.sup.3 or less to exhibit the effects of the
invention.
[0037] Incidentally, the density at 15.degree. C. is measured by
JIS K 2240, "Liquefied Petroleum Gases 5.7 or 5.8 Calculation
method for density and vapor pressure".
[0038] Further, the corrosiveness to copper of a fuel according to
the invention is not particularly restricted, however, the
corrosiveness thereof is preferable to 1 or less at 40.degree. C.
for 1 hour because deterioration of a fuel cell system comprising
such as a reforming catalyst, a water gas shift reaction catalyst,
a carbon monoxide removal catalyst, fuel cell stacks, and the like
can be suppressed to low and the initial performances can be
maintained for a long duration.
[0039] Incidentally, the corrosiveness to copper at 40.degree. C.
for 1 hour is measured by JIS K 2240, "Liquefied Petroleum Gases
5.10 Corrosiveness to copper".
[0040] Further, in the invention, heat capacity of a fuel is not
particularly restricted, however, the heat capacity is preferably
1.7 kJ/kg.multidot..degree. C. or less at 15.degree. C. and in
gaseous phase in view of a low fuel consumption of a fuel cell
system as a whole.
[0041] The heat capacity is measured by means of calorimeters such
as water calorimeter, ice calorimeter, vacuum calorimeter,
adiabatic calorimeter and the like.
[0042] A production method of the fuel of the invention is not
particularly restricted. As a practical method, for example, the
fuel can be prepared by blending one or more of the following
hydrocarbon base materials; a straight-run propane fraction
containing propane as a main component obtained by treating heavy
oils with a distillation apparatus, naphtha reforming apparatus and
the like, a straight-run desulfurized propane fraction obtained by
desulfurizing the straight-run propane fraction, a straight-run
butane fraction containing butane as a main component obtained by
treating heavy oils with a distillation apparatus, naphtha
reforming apparatus, alkylation apparatus and the like, a
straight-run desulfurized butane fraction obtained by desulfurizing
the straight-run butane fraction, a cracked propane fraction
containing propane and propylene as main components obtained by
cracking heavy oils with a fluid catalytic cracking apparatus (FCC)
and the like, a cracked butane fraction containing butane and
butene as main components obtained by treating heavy oils with a
fluid catalytic cracking apparatus (FCC) and the like.
[0043] Among them, preferable materials as the base materials for
the production of the fuel of the invention are the straight-run
desulfurized propane fraction, the straight-run desulfurized butane
fraction and the like.
[0044] A fuel of the invention is to be employed as a fuel for a
fuel cell system. A fuel cell system mentioned herein comprises a
reformer for a fuel, a carbon monoxide conversion apparatus, fuel
cells and the like, however, a fuel of the invention may be
suitable for any fuel cell system.
[0045] The reformer is an apparatus for obtaining hydrogen, by
reforming a fuel. Practical examples of the reformer are:
[0046] (1) a steam reforming type reformer for obtaining products
of mainly hydrogen by treating a heated and vaporized fuel and
steam with a catalyst such as copper, nickel, platinum, ruthenium
and the like;
[0047] (2) a partial oxidation type reformer for obtaining products
of mainly hydrogen by treating a heated and vaporized fuel and air
with or without a catalyst such as copper, nickel, platinum,
ruthenium and the like; and
[0048] (3) an auto thermal reforming type reformer for obtaining
products of mainly hydrogen by treating a heated and vaporized
fuel, steam and air, which carries out the partial oxidation of (2)
in the prior stage and carries out the steam type reforming of (1)
in the posterior stage while using the generated heat of the
partial oxidation reaction with a catalyst such as copper, nickel,
platinum, ruthenium and the like.
[0049] The carbon monoxide conversion apparatus is an apparatus for
removing carbon monoxide which is contained in a gas produced by
the above-described reformer and becomes a catalyst poison in a
fuel cell and practical examples thereof are:
[0050] (1) a water gas shift reactor for obtaining carbon dioxide
and hydrogen as products from carbon monoxide and steam by reacting
a reformed gas and steam in the presence of a catalyst of such as
copper, nickel, platinum, ruthenium and the like; and
[0051] (2) a preferential oxidation reactor for converting carbon
monoxide into carbon dioxide by reacting a reformed gas and
compressed air in the presence of a catalyst of such as platinum,
ruthenium and the like, and these are used singly or jointly.
[0052] As a fuel cell, practical examples are a proton exchange
membrane type fuel cell (PEFC), a phosphoric acid type fuel cell
(PAFC), a molten carbonate type fuel cell (MCFC), a solid oxide
type fell cell (SOFC) and the like.
[0053] Further, the above-described fuel cell system can be
employed for an electric automobile, a hybrid automobile comprising
a conventional engine and electric power, a portable power source,
a dispersion type power source, a power source for domestic use, a
cogeneration system and the like.
EXAMPLES
[0054] The properties of base materials (LPG) employed for the
respective fuels for examples and comparative examples are shown in
Table 1.
[0055] Also, the compositions and properties of the respective
fuels employed for examples and comparative examples are shown in
Table 2.
1 TABLE 1 straight-run straight-run desulfurized FCC-C3 FCC-C4 C3
fraction C4 fraction fraction fraction *1 *2 *3 *4 DME *5 sulfur
mass ppm 7 <1 5 34 <1 density @ 15.degree. C. 0.509 0.577
0.518 0.591 0.600 vapor pressure @ 40.degree. C. Mpa 1.33 0.34 1.50
0.39 0.88 corrosiveness to copper 1a 1a 1a 1 -- carbon number:
C.sub.2- mol. % 2.5 0.0 0.0 0.0 -- carbon number: C.sub.3 mol. %
96.6 0.0 99.8 2.4 -- carbon number: C.sub.4 mol. % 0.9 99.9 0.2
92.4 -- carbon number: C.sub.5+ mol. % 0.0 0.1 0.0 5.2 -- saturates
mol. % 99.9 99.9 19.7 53.9 -- olefins mol. % 0.1 0.1 80.3 46.1 --
butadiene mol. % 0.0 0.0 0.0 0.2 -- isoparaffines in mol. % 78.2
35.8 100.0 81.4 -- saturates having carbon numbers of 4 or more *1:
fractions containing propane as a main component obtained by
treating heavy oils with a distillation apparatus, naphtha
reforming apparatus and the like *2: those obtained by
desulfurization of fractions containing butane as a main component
obtained by treating heavy oils with a distillation apparatus,
naphtha reforming apparatus, alkylation apparatus and the like *3:
fractions containing propane and propylene as main components
obtained by treating heavy oils with a fluid catalytic cracking
apparatus (FCC) and the like *4: fractions containing butane and
butene as main components obtained by treating heavy oils with a
fluid catalytic cracking apparatus (FCC) and the like *5:
dimethylether
[0056]
2 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Comp. 1 Comp. 2 Mixing ratio (vol. %)
straight-run C3 fraction 100 25 straight-run desulfurized C4
fraction 100 75 FCC-C3 fraction 94 FCC-C4 fraction 100 ethane 6
Analytical resuits of properties sulfur mass ppm 7 <1 2 5 34
density g/cm.sup.3 0.509 0.577 0.560 0.508 0.591 vapor pressure Mpa
1.33 0.34 0.60 1.75 0.36 distribution of carbon carbon number:
C.sub.2- mol. % 2.5 0.0 0.7 5.8 0.0 numbers (hydrocarbon carbon
number: C.sub.3 mol. % 96.6 0.0 27.1 94.0 2.4 moieties) carbon
number: C.sub.4 mol. % 0.9 99.9 72.1 0.2 92.4 carbon number:
C.sub.5+ mol. % 0.0 0.1 0.1 0.0 5.2 composition saturates mol. %
99.9 99.9 99.9 24.4 53.9 olefins mol. % 0.1 0.1 0.1 75.6 46.1
butadiene mol. % 0.0 0.0 0.0 0.0 0.2 isoparaffines in saturates
having mol. % 78.2 35.8 35.9 100.0 80.6 carbon numbers of 4 or more
corrosiveness to copper 1a 1a 1a 1a 1 net heat of combustion kJ/kg
46330 45670 45820 45930 45440 heat capacity gas kJ/kg .multidot.
.degree. C. 1.62 1.62 1.62 1.52 1.55
[0057] These respective fuels were subjected to evaluation tests
for a fuel cell system.
[0058] Fuel Cell System Evaluation Test
[0059] (1) Steam Reforming
[0060] A fuel and water were evaporated by electric heating and led
to a reformer filled with a noble metal type catalyst and kept at a
prescribed temperature by an electric heater to generate a reformed
gas enriched with hydrogen.
[0061] The temperature of the reformer was adjusted to be the
minimum temperature (the minimum temperature at which no THC was
contained in a reformed gas) at which reforming was completely
carried out in an initial stage of the test.
[0062] Together with steam, a reformed gas was led to a carbon
monoxide conversion apparatus (a water gas shift reaction) to
convert carbon monoxide in the reformed gas to carbon dioxide and
then the produced gas was led to a solid polymer type fuel cell to
carry out power generation.
[0063] A flow chart of a steam reforming type fuel cell system
employed for the evaluation was illustrated in FIG. 1.
[0064] (2) Partial Oxidation
[0065] A fuel is evaporated by electric heating and together with
air, the evaporated fuel was led to a reformer filled with a noble
metal type catalyst and kept at a 1100.degree. C. by an electric
heater to generate a reformed gas enriched with hydrogen.
[0066] Together with steam, a reformed gas was led to a carbon
monoxide conversion apparatus (a water gas shift reaction) to
convert carbon monoxide in the reformed gas to carbon dioxide and
then the produced gas was led to a solid polymer type fuel cell to
carry out power generation.
[0067] A flow chart of a partial oxidation type fuel cell system
employed for the evaluation was illustrated in FIG. 2.
[0068] (3) Evaluation Method
[0069] The amounts of H.sub.2, CO, CO.sub.2 and THC in the reformed
gas generated from a reformer were measured immediately after
starting of the evaluation test. Similarly, the amounts of H.sub.2,
CO, CO.sub.2 and THC in the reformed gas generated from a carbon
monoxide conversion apparatus were measured immediately after
starting of the evaluation test.
[0070] The power generation quantity, the fuel consumption, and the
CO.sub.2 amount emitted out of a fuel cell were measured
immediately after starting of the evaluation test and 100 hours
later from the starting.
[0071] The energy (preheating quantities) necessary to heat the
respective fuels to a prescribed reforming temperature were
calculated from the heat capacities and the heat of
vaporization.
[0072] Further, these measured values, calculated values and the
heating values of respective fuels were employed for calculation of
the performance deterioration ratio of a reforming catalyst (the
power generation amount after 100 hours later from the starting
divided by the power generation amount immediately after the
starting), the thermal efficiency (the power generation amount
immediately after the starting divided by the net heat of
combustion of a fuel), and the preheating energy ratio (preheating
energy divided by the power generation amount).
[0073] The respective measured values and the calculated values are
shown in Table 3.
3 TABLE 3 Ex. 1 Ex. 2 Ex. 3 Comp. 1 Comp. 2 Evaluation results
Electric power generation by steam reforming method (reforming
temperature = optimum reforming temperature 1)) Optimum reforming
.degree. C. 650 640 640 680 670 temperature Electric energy kJ/fuel
kg initial performance 31140 30700 30800 29180 29460 100 hours
later 31110 30690 30780 28700 28520 performance deterioration ratio
100 hours later 0.10% 0.03% 0.06% 1.64% 3.19% Thermal efficiency 2)
initial performance 67% 67% 67% 64% 65% CO.sub.2 generation kg/fuel
kg initial performance 2.993 3.029 3.021 3.102 3.079 Energy per
CO.sub.2 KJ/CO.sub.2-kg initial performance 10404 10135 10195 9407
9568 Preheating energy 3) kJ/fuel kg 1010 1000 1000 1000 1000
Preheating energy ratio 4) 3.2% 3.3% 3.2% 3.4% 3.4% Electric power
generation by partial oxidation retorming method (reforming
temperature 1100.degree. C.) Electric energy kJ/fuel kg initial
performance 16200 15590 15730 14020 14420 100 hours later 16190
15590 15720 13910 14220 performance 100 hours later 0.06% 0.00%
0.06% 0.78% 1.39% deterioration ratio Thermal efficiency 2) initial
performance 35% 34% 34% 30% 32% CO.sub.2 generation kg/fuel kg
initial performance 2.992 3.028 3.019 3.101 3.077 Energy per
CO.sub.2 KJ/CO.sub.2-kg initial performance 5414 5149 5210 4521
4686 Preheating energy 3) kJ/fuel kg 1740 1750 1740 1630 1670
Preheating energy ratio 4) 10.7% 11.2% 11.1% 11.6% 11.6% 1) the
minimum temperature at which no THC is contained in a reformed gas
2) electric energy/net heat of combustion of fuel 3) energy
necessary for heating a fuel to a reforming temperature 4)
preheating energy/electric energy
INDUSTRIAL APPLICABILITY
[0074] As described above, a fuel of the invention containing
hydrocarbon compounds with specific compositions has performances
with small deterioration by using in a fuel cell system and can
provide high output of electric energy and other than that, the
fuel can satisfy a variety of performances for a fuel cell
system.
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