Fuel cell as molten carbonate fuel cell (MCFC) operates at high temperatures. Thus, cogeneration processes may be performed, generating heat for its own process or for other purposes of steam generation in the industry. The use of ethanol is one of the best options because this is a renewable and less environmentally offensive fuel, and is cheaper than oil-derived hydrocarbons, as in the case of Brazil. In that country, because of technical, environmental, and economic advantages, the use of ethanol by steam reforming process has been the most investigated process. The objective of this study is to show a thermodynamic analysis of steam reforming of ethanol, to determine the best thermodynamic conditions where the highest volumes of products are produced, making possible a higher production of energy, that is, a more efficient use of resources. To attain this objective, mass and energy balances were performed. Equilibrium constants and advance degrees were calculated to get the best thermodynamic conditions to attain higher reforming efficiency and, hence, higher electric efficiency, using the Nernst equation. The advance degree (according to Castellan 1986, Fundamentos da Fisica/Quimica, Editora LTC, Rio de Janeiro, p. 529, in Portuguese) is a coefficient that indicates the evolution of a reaction, achieving a maximum value when all the reactants’ content is used of reforming increases when the operation temperature also increases and when the operation pressure decreases. However, at atmospheric pressure $(1atm)$, the advance degree tends to stabilize in temperatures above $700°C$; that is, the volume of supplemental production of reforming products is very small with respect to high use of energy resources necessary. The use of unused ethanol is also suggested for heating of reactants before reforming. The results show the behavior of MCFC. The current density, at the same tension, is higher at $700°C$ than other studied temperatures such as 600 and $650°C$. This fact occurs due to smaller use of hydrogen at lower temperatures that varies between 46.8% and 58.9% in temperatures between 600 and $700°C$. The higher calculated current density is $280mA∕cm2$. The power density increases when the volume of ethanol to be used also increases due to higher production of hydrogen. The highest produced powers at $190mA∕cm2$ are 99.8, 109.8, and $113.7mW∕cm2$ for 873, 923, and $973K$, respectively. The thermodynamic efficiency has the objective to show the connection among operational conditions and energetic factors, which are some parameters that describe a process of internal steam reforming of ethanol.

1.
Ioannides
,
T.
, 2001, “
Thermodynamic Analysis of Ethanol Processors for Fuel Cells Applications
,”
J. Power Sources
0378-7753, Vol.
92
, pp.
17
25
.
2.
Silveira
,
J. L.
, and
Leal
,
E. M.
, 2001, “
Análise do Uso de Etanol em Células de Combustível do Tipo Carbonato Fundido
,”
, Guaratinguetá, Brazil, pp.
1
6
, in Portuguese.
3.
Vasudeva
,
K.
,
Mitra
,
N.
,
Umasankar
,
P.
,
Dhingra
,
S. C.
, 1996, “
Steam Reforming of Ethanol for Hydrogen Production: Thermodynamic Analysis
,”
Int. J. Hydrogen Energy
0360-3199,
21
(
1
), pp.
13
18
.
4.
Leal
,
E. M.
, 2000, “
Análise Técnico-Econômica de Sistemas de Cogeração Utilizando Células de Combustível: Estudos de Casos
,” Master thesis, São Paulo State University, Campus of Guaratinguetá, p.
199
, in Portuguese.
5.
Sosa
,
M. I.
,
Fushimi
,
A.
, 2000, “
La Cogeneración em el Contexto de las Tecnologias de Conversión Energética del Futuro, AVERMA—Avances em Energias Renovables y Médio Ambiente
,” Resistência, Argentina, Vol.
4
, No.
2
, pp.
07.01
07.06
, in Spanish.
6.
Selman
,
J. R.
, 1993, “
Research, Development and Demonstration of Molten Carbonate Fuel Cell Systems
,”
Fuel Cell Systems
,
1st ed.
,
L. J. M. J.
Blomen
and
M. N.
Mugerwa
, eds.,
Plenum
,
New York
, pp.
345
463
.
7.
Appleby
,
A. J.
, “
Characteristics of Fuel Cell Systems
,”
Fuel Cell Systems
,
L. J. M. J.
Blomen
and
M. N.
Mugerwa
, eds.,
Plenum
,
New York
, pp.
157
199
.
8.
Maggio
,
G.
,
Freni
,
S.
,
Cavallaro
,
S.
, 1998, “
Light Alcohols/Methane Fuelled Molten Carbonate Fuel Cells: A Comparative Study
,”
J. Power Sources
0378-7753,
74
(
1
), pp.
17
23
.
9.
Freni
,
S.
,
Maggio
,
G.
, and
Cavallaro
,
S.
, 1996, “
Ethanol Steam Reforming in a Molten Carbonate Fuel Cell: A Thermodynamic Approach
,”
J. Power Sources
0378-7753,
62
, pp.
67
73
.
10.
Cavallaro
,
S.
,
Freni
,
S.
, 1996, “
Ethanol Steam Reforming in a Molten Carbonate Fuel Cell: A Preliminary Kinetic Investigation
,”
Int. J. Hydrogen Energy
0360-3199
21
(
6
), pp.
465
469
.
11.
Souza
,
A. C. C.
, 2005, “
Análise Técnica e Econômica de um Reformador de Etanol para Produção de hidrogênio
,” Guaratinguetá, Brazil, Master thesis, São Paulo State University, Campus of Guaratinguetá, p.
139
, in Portuguese.
12.
Cavallaro
,
S.
,
Freni
,
S.
,
Cannistraci
,
R.
,
Aquino
,
M.
, and
Giordano
,
N.
, 1992, “
Steam Reforming of Various Fuels
,”
Int. J. Hydrogen Energy
0360-3199
17
(
3
), pp.
181
210
.