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Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol
10th International Symposium on Process Systems Engineering - PSE2009 Rita Maria de Brito Alves, Claudio Augusto Oller do Nascimento and Evaristo Chalbaud Biscaia Jr. (Editors) © 2009 Elsevier B.V. All rights reserved.
987
Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol Giovanilton F. Silva,a Andrea L. O. Fereira,a Samuel J. M. Cartaxo,a Fabiano A. N. Fernandesa a
Department of Chemical Engineering, UFC-Universidade Federa do Ceará Campus do Pici, Bloco 709, Pici, 60455-760 – Ceará – Brazil
Abstract This case study focused on optimization of hydrogen production for fuel cell applications. In this case study, glycerol was chosen as a raw material and with autothermal reforming as a process of produce hydrogen. Using a commercial dynamic flow sheeting software, HYSYS 3.1, the process of hydrogen production was successfully simulated. In this research, fuel processor consists of an autothermal reactor, three water gas shift reactors and a preferential oxidation reactor was successfully developed. The purpose of this case study is to identify the effect of various operating parameters such as air-to-fuel (A/F) ratio and steam-to-fuel (S/F) ratio to get the optimum hydrogen production while made carbon monoxide lower than 10 %. From the results, an optimum A/F and S/F ratio are 5.5 and 3.5, respectively to produce hydrogen – 34.7 % (v/v), CO2 – 60% (v/v), and CO – 0.02% (v/v). Under these optimum conditions, 83.6% of fuel processor efficiency was achieved. Keywords: glycerol, hydrogen, autothermal reforming, HYSYS.
1. Introduction Hydrogen will play an important role as an energy carrier of the future. Hydrogen will be used as fuel in almost every application where fossil fuels are being used today, plus the advantages of hydrogen to compare with other fossil fuels is hydrogen fuel will not emission harmful or hazardous gas. There are three categories that been analyzed for input or raw material for hydrogen production. The categories that had been studied was natural gas (consist methane, ethane, propane and butane), alcohol (methanol, ethanol and glycerol) and naphtha (kerosene or fuel jet, gasoline and diesel). An increase in biodiesel production would decrease the world market price of glycerol. Glycerol is a waste by-product obtained during the production of biodiesel. Biodiesel is one of the alternative fuels used to meet our energy requirements and also carbon dioxide emission is much lesser when compared to regular diesel fuel. Biodiesel and glycerol are produced from the transesterification of vegetable oils and fats with alcohol in the presence of a catalyst. About 10 wt% of vegetable oil is converted into glycerol during the transesterification process. Although glycerol is used in medicines, cosmetics, and sweetening agents, world demand is limited. As such, when mass production of the biodiesel is realized, novel processes that utilize glycerol must be developed. When biodiesel is produced in large quantity, it is important to find useful applications for the resulting large quantity of glycerol in the world market. Tyson (2003) reported that glycerol markets are limited; an increase in biodiesel production may cause glycerol
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G.F. Silva et al.
prices to decline from $1/L to $0.7/L by 2010. The money invested in purifying the glycerol would also be high (Prakash, 1998). Also, Tyson, 2003 reported that net biodiesel production costs can be reduced from US$0.63/litre of B100 to US$0.38/litre of B100 by adding value to the glycerol by-product. Glycerol is a potential feedstock, for hydrogen production because one mole of glycerol can produce up to four moles of hydrogen. Hydrogen (H2) is mostly used in refinery hydrotreating operations, ammonia production and fuel cells (Rapagna et al., 1998). When glycerol is cracked at high temperature to produce hydrogen, it is possible to get carbon monoxide as one of the gaseous products. Studies on the degradation of glycerol have been also presented in previous papers, (Herai et al., Bühler et al. and Sadashiv et al.). One possibility is to use glycerol as a source of hydrogen, and, in this regard, steam reforming of glycerol would be a suitable reaction. In the autothermal reforming of glycerol, synthesis gas that contains both carbon monoxide (CO) and hydrogen (H2) is produced. Steam-reforming is endothermic and partial oxidation is exothermic. It is possible to reaction glycerol and other hydrocarbon fuels with a mixture of steam and oxygen or steam and air and carry out both reactions simultaneously. The exothermic oxidation supplies the energy for the endothermic reforming. Careful control of the oxygen content of the entering mixture is essential in these processes for maintaining proper reaction temperatures. The products of these reactions are carbon monoxide, carbon dioxide, and hydrogen. The CO requires high- and low temperature water gas shifts to oxidize it and provide additional hydrogen (Brown, 2001). Autothermal reforming is a combination of steam reforming and partial oxidation and some other reaction that occurred depend on the conversion of raw material, catalyst used, ratio of raw material and the temperature provide during the process (Iwasaki et al., 2005). Lenz et al. (2005) described that autothermal reforming is known as the simultaneous conversion of hydrocarbons with steam and oxygen. The endothermic steam reforming reaction is generally given by four reactions: Partial oxidation: C3 H 8O3 2O2 o 3CO 4 H 2O (1) Parallel Steam reforming of glycerol: C3 H 8O3 3H 2O o 3CO2 7 H 2 (2) Series Water-gas shift reaction: CO H 2O o CO2 H 2 (3) Overall reaction: 2C3 H 8O3 H 2O 2O2 o 5CO2 9 H 2 CO (4)
2. Simulation and Optimization 2.1 Problem definition The hydrogen production from glycerol for fuel cell was simulated using HYSYS software as a Figure 1 shows it. Typically, the simulation process takes the following stages: i. Preparation Stage a) Selecting the thermodynamic model b) Define chemical components ii. Building Stage a) Adding and define streams
989
Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol
b) Adding and define unit operations i. Auto-thermal reforming reactor ii. Water gas shift reactor 1. High temperature shift reactor 2. Medium temperature shift reactor 3. Low temperature shift reactor c) Connecting streams to unit operations d) Add auxiliary unit i. Heater ii. Cooler iii. Heat exchanger iii. Execution a) Starting integration b) Optimization the whole plant
Figure 1 – HYSYS process flow diagram (PFD) of Reforming Glycerol plant. The system considered in this study were simulated with the same basic data, show within Table 1. The Peng-Robinson Equation of State (EOS) is used to model the thermodynamics of hydrogen production for both steady-state. Table 1 – Steady state operating conditions. The parameter of simulation Feed flow rate of glycerol (kmol/h) Reformer temperature (°C) Reformer pressure (250 kPa) Vapor pressure ( kPa) Air temperature (°C)
Value 100 500 250 500 25
The system fuel processor efficiency can be calculated by:
K
nH 2 LHVH 2
nCO LHVCO
nC3 H 8O3 LHVC3 H 8O3
The lower heating value (LHV) of hydrogen, CO and glycerol are shown in Table 2.
(5)
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Table 2 - Lower heating value (LHV) for hydrogen, CO and glycerol. Component LHV (kJ/kmol) Glycerol 1470 Hidrogen 241.83 CO 282.00 2.2 Optimization Optimization of the autothermal reforming of glycerol was conducted searching for the operating conditions (air-to-fuel (A/F) ratio and steam-to-fuel (S/F) ratio) that result in the highest production hydrogen. HYSYS contains a multi-variable Steady State Optimizer. The Flowsheet has been built and a converged solution has been obtained, it can use the Optimizer to find the operating conditions which minimize or maximize an Objective Function. The Objective function is given by optimization of Eq. (5). For maximize of objective functions was used the method SQP - Sequential Quadratic Programming. CO should decrease because fuel cells (FC) do not tolerate excessive amounts of CO. The FC does not tolerate more than in the order of 50ppm CO; the lower the CO concentration, the higher the efficiency of the cell. H2/glycerol ratio should be increased because all glycerol would be reacted to product (H2).
3. Results and Discussions Optimization for ATR was done by varying the air molar flow rate to get the best flow rate of air to be introduced into the ATR. Two case studies were developed in order to do this optimization. The first case study was developed to monitor the temperature at the ATR vapour stream after varying the air molar flow rate from 350 kmol/h to 800 kmol/h. The second case study was developed to monitor the molar flow rate of carbon monoxide and hydrogen after varying air molar flow rate within the range that was chosen from first case study. The result is shown in Figures 2 and 3. From Figure 2, the temperature out of ATR is over 800 °C only after the molar flow rate of air greater or equal 600 kmol/h. With that air molar flow rate range, the hydrogen and CO molar flow rate was monitored. From figure 3, the flow rate of hydrogen produced by the reactor reforming of is decreasing when of air molar flow rate greater than 550 kmol/h. Then it began constant after 750 kmol/h. 1100
Temperature °C
1000
900
800
700
600
500 300
400
500
600
700
800
Air - Molar Flow (kgmole/h)
Figure 2 – Temperature of reactor of reforming for varies air Feed molar flow
H2
Molar Flow of CO (kgmole/h)
120
CO
340 320
100
300
80
280
60
260 40 240 20
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Molar Flow of H2 (kgmole/h)
Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol
220 0 300
400
500
600
700
800
Air - Molar Flow (kgmole/h)
Figure 3 - Molar flow of CO and H2 effluent for varies air feed molar flow. In Water Gas Shift Optimization , one case study was developed to optimized value of feed water molar flow to reduce concentration of CO through water gas shift reaction. Figure 3 shows the result of case study where the concentration of H2 and CO after water gas shift reactors was monitored. Water molar flow rate was optimized from 2000 to 8000 kg/h. As we can see from Figure 5.8, the H2 show an increasing slope and the increasing is a bit slower at 7500 kg/h. The optimum water molar flow rate was taken when hydrogen at its higher molar flow rate. So, the value of water molar flow rate that was chosen was 5500 kg/h. At this point, H2 produced the greatest flow rate and CO reduced the lowest flow rate.
Molar Flow of H2 (kgmole/h)
326
8
Hydrogen
324
CO
322
6
320
4
318 2
316
Molar Flow of CO (kgmole/h)
10 328
314 2000
3000
4000
5000
6000
7000
8000
0
Steam - Massa flow (kg/h)
Figure – 3 Molar flow of CO and H2 effluent for varies water feed molar flow. In the following, the results obtained for an autothermal reforming of glycerol system are presented. With the developed system models which are implemented in the HYSYS 3.1 process simulator, effluents from all reactors are simulated. In this model, the air to fuel ratio is set to 5.5 and the steam to fuel ratio is set to 3.5 In these conditions, 90% glycerol is converted to produce 34% hydrogen, 20.07% CO2 and 0.01% CO. Also, under these conditions, oxygen is 100% consumed. As we know, WGS reaction will convert CO into CO2 and hydrogen with the existence of steam.
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Therefore, the percentage of CO is decreasing, while the percentage of CO2 and hydrogen is increasing respectively. In the same time, the percentage of steam is decreasing.
4. CONCLUSIONS Basically, for 100 kmol/h of glycerol was inserted to the process and it produced about 327.37 kmol/h hydrogen. For the first reactor that is at the reforming reactor, hydrogen that produced after the optimization was 262.65 kmol/h. Optimization had been done for every reactor where by for the ATR reactor, we got 550 kmol/h of air for the highest hydrogen production and the lowest CO besides temperature around 672.9 °C. A number of important observations were noted based on the analysis of conclusions: 1. The simulation of hydrogen production plant model using autothermal reforming of methanol had been successfully developed using HYSYS 3.1. 2. The optimum A/F and S/F ratios are 5.5 and 3.5, respectively to produce hydrogen – 34.7 % (v/v), CO2 – 60% (v/v), and CO – 0.02% (v/v). 3. With optimum parameters above, 83.6% of fuel processor efficiency was achieved.
References Brown, L.F. A Comparative Study of Fuels for On-Board Hydrogen Production for Fuel-CellPowered Automobiles. International Journal of Hydrogen Energy. 26:381-397, 2001. Bühler, W. E. Dinjus, H.J. Ederer, A. Kruse, C. Mas, Ionic reactions and pyrolysis of glycerol as competing reaction pathways in near- and supercritical water, Journal of Supercritical Fluids 22 37–53, 2002. Hirai, T., N.O. Ikenaga, T. Miyake, and T. Suzuki. Production of hydrogen by steam reforming of glycerin on ruthenium catalyst. Energy and Fuels 9: 1761-1762, 2005. Lenz, B. and Aicher, T.. Catalytic Autothermal Reforming of Jet Fuel. Journal of Power Sources. 149:44-52, 2005. Prakash, C.B., “A Critical Review of Biodiesel as a Transportation Fuel in Canada”, Report to Transportation System Branch, Air Pollution Prevention Directorate, R gasification Biomass to produce Hydrogen Rich Gas”, Int. J. Hydrogen Energy 23, 551-557, 1998. Rapagna, S., N. Jand and U.P. Foscolo, “Catalytic Gasification Biomass to produce Hydrogen Rich Gas”, Int. J. Hydrogen Energy 23, 551-557 1998. Sadashiv M. Swami and Martin A. Abraham, Integrated Catalytic Process for Conversion of Biomass to Hydrogen, Energy & Fuels, 20, 2616-2622, 2006. Tyson K. S., “Biodiesel R & D”, Montana Biodiesel Workshop, October 8, 2003.
987
Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol Giovanilton F. Silva,a Andrea L. O. Fereira,a Samuel J. M. Cartaxo,a Fabiano A. N. Fernandesa a
Department of Chemical Engineering, UFC-Universidade Federa do Ceará Campus do Pici, Bloco 709, Pici, 60455-760 – Ceará – Brazil
Abstract This case study focused on optimization of hydrogen production for fuel cell applications. In this case study, glycerol was chosen as a raw material and with autothermal reforming as a process of produce hydrogen. Using a commercial dynamic flow sheeting software, HYSYS 3.1, the process of hydrogen production was successfully simulated. In this research, fuel processor consists of an autothermal reactor, three water gas shift reactors and a preferential oxidation reactor was successfully developed. The purpose of this case study is to identify the effect of various operating parameters such as air-to-fuel (A/F) ratio and steam-to-fuel (S/F) ratio to get the optimum hydrogen production while made carbon monoxide lower than 10 %. From the results, an optimum A/F and S/F ratio are 5.5 and 3.5, respectively to produce hydrogen – 34.7 % (v/v), CO2 – 60% (v/v), and CO – 0.02% (v/v). Under these optimum conditions, 83.6% of fuel processor efficiency was achieved. Keywords: glycerol, hydrogen, autothermal reforming, HYSYS.
1. Introduction Hydrogen will play an important role as an energy carrier of the future. Hydrogen will be used as fuel in almost every application where fossil fuels are being used today, plus the advantages of hydrogen to compare with other fossil fuels is hydrogen fuel will not emission harmful or hazardous gas. There are three categories that been analyzed for input or raw material for hydrogen production. The categories that had been studied was natural gas (consist methane, ethane, propane and butane), alcohol (methanol, ethanol and glycerol) and naphtha (kerosene or fuel jet, gasoline and diesel). An increase in biodiesel production would decrease the world market price of glycerol. Glycerol is a waste by-product obtained during the production of biodiesel. Biodiesel is one of the alternative fuels used to meet our energy requirements and also carbon dioxide emission is much lesser when compared to regular diesel fuel. Biodiesel and glycerol are produced from the transesterification of vegetable oils and fats with alcohol in the presence of a catalyst. About 10 wt% of vegetable oil is converted into glycerol during the transesterification process. Although glycerol is used in medicines, cosmetics, and sweetening agents, world demand is limited. As such, when mass production of the biodiesel is realized, novel processes that utilize glycerol must be developed. When biodiesel is produced in large quantity, it is important to find useful applications for the resulting large quantity of glycerol in the world market. Tyson (2003) reported that glycerol markets are limited; an increase in biodiesel production may cause glycerol
988
G.F. Silva et al.
prices to decline from $1/L to $0.7/L by 2010. The money invested in purifying the glycerol would also be high (Prakash, 1998). Also, Tyson, 2003 reported that net biodiesel production costs can be reduced from US$0.63/litre of B100 to US$0.38/litre of B100 by adding value to the glycerol by-product. Glycerol is a potential feedstock, for hydrogen production because one mole of glycerol can produce up to four moles of hydrogen. Hydrogen (H2) is mostly used in refinery hydrotreating operations, ammonia production and fuel cells (Rapagna et al., 1998). When glycerol is cracked at high temperature to produce hydrogen, it is possible to get carbon monoxide as one of the gaseous products. Studies on the degradation of glycerol have been also presented in previous papers, (Herai et al., Bühler et al. and Sadashiv et al.). One possibility is to use glycerol as a source of hydrogen, and, in this regard, steam reforming of glycerol would be a suitable reaction. In the autothermal reforming of glycerol, synthesis gas that contains both carbon monoxide (CO) and hydrogen (H2) is produced. Steam-reforming is endothermic and partial oxidation is exothermic. It is possible to reaction glycerol and other hydrocarbon fuels with a mixture of steam and oxygen or steam and air and carry out both reactions simultaneously. The exothermic oxidation supplies the energy for the endothermic reforming. Careful control of the oxygen content of the entering mixture is essential in these processes for maintaining proper reaction temperatures. The products of these reactions are carbon monoxide, carbon dioxide, and hydrogen. The CO requires high- and low temperature water gas shifts to oxidize it and provide additional hydrogen (Brown, 2001). Autothermal reforming is a combination of steam reforming and partial oxidation and some other reaction that occurred depend on the conversion of raw material, catalyst used, ratio of raw material and the temperature provide during the process (Iwasaki et al., 2005). Lenz et al. (2005) described that autothermal reforming is known as the simultaneous conversion of hydrocarbons with steam and oxygen. The endothermic steam reforming reaction is generally given by four reactions: Partial oxidation: C3 H 8O3 2O2 o 3CO 4 H 2O (1) Parallel Steam reforming of glycerol: C3 H 8O3 3H 2O o 3CO2 7 H 2 (2) Series Water-gas shift reaction: CO H 2O o CO2 H 2 (3) Overall reaction: 2C3 H 8O3 H 2O 2O2 o 5CO2 9 H 2 CO (4)
2. Simulation and Optimization 2.1 Problem definition The hydrogen production from glycerol for fuel cell was simulated using HYSYS software as a Figure 1 shows it. Typically, the simulation process takes the following stages: i. Preparation Stage a) Selecting the thermodynamic model b) Define chemical components ii. Building Stage a) Adding and define streams
989
Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol
b) Adding and define unit operations i. Auto-thermal reforming reactor ii. Water gas shift reactor 1. High temperature shift reactor 2. Medium temperature shift reactor 3. Low temperature shift reactor c) Connecting streams to unit operations d) Add auxiliary unit i. Heater ii. Cooler iii. Heat exchanger iii. Execution a) Starting integration b) Optimization the whole plant
Figure 1 – HYSYS process flow diagram (PFD) of Reforming Glycerol plant. The system considered in this study were simulated with the same basic data, show within Table 1. The Peng-Robinson Equation of State (EOS) is used to model the thermodynamics of hydrogen production for both steady-state. Table 1 – Steady state operating conditions. The parameter of simulation Feed flow rate of glycerol (kmol/h) Reformer temperature (°C) Reformer pressure (250 kPa) Vapor pressure ( kPa) Air temperature (°C)
Value 100 500 250 500 25
The system fuel processor efficiency can be calculated by:
K
nH 2 LHVH 2
nCO LHVCO
nC3 H 8O3 LHVC3 H 8O3
The lower heating value (LHV) of hydrogen, CO and glycerol are shown in Table 2.
(5)
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G.F. Silva et al.
Table 2 - Lower heating value (LHV) for hydrogen, CO and glycerol. Component LHV (kJ/kmol) Glycerol 1470 Hidrogen 241.83 CO 282.00 2.2 Optimization Optimization of the autothermal reforming of glycerol was conducted searching for the operating conditions (air-to-fuel (A/F) ratio and steam-to-fuel (S/F) ratio) that result in the highest production hydrogen. HYSYS contains a multi-variable Steady State Optimizer. The Flowsheet has been built and a converged solution has been obtained, it can use the Optimizer to find the operating conditions which minimize or maximize an Objective Function. The Objective function is given by optimization of Eq. (5). For maximize of objective functions was used the method SQP - Sequential Quadratic Programming. CO should decrease because fuel cells (FC) do not tolerate excessive amounts of CO. The FC does not tolerate more than in the order of 50ppm CO; the lower the CO concentration, the higher the efficiency of the cell. H2/glycerol ratio should be increased because all glycerol would be reacted to product (H2).
3. Results and Discussions Optimization for ATR was done by varying the air molar flow rate to get the best flow rate of air to be introduced into the ATR. Two case studies were developed in order to do this optimization. The first case study was developed to monitor the temperature at the ATR vapour stream after varying the air molar flow rate from 350 kmol/h to 800 kmol/h. The second case study was developed to monitor the molar flow rate of carbon monoxide and hydrogen after varying air molar flow rate within the range that was chosen from first case study. The result is shown in Figures 2 and 3. From Figure 2, the temperature out of ATR is over 800 °C only after the molar flow rate of air greater or equal 600 kmol/h. With that air molar flow rate range, the hydrogen and CO molar flow rate was monitored. From figure 3, the flow rate of hydrogen produced by the reactor reforming of is decreasing when of air molar flow rate greater than 550 kmol/h. Then it began constant after 750 kmol/h. 1100
Temperature °C
1000
900
800
700
600
500 300
400
500
600
700
800
Air - Molar Flow (kgmole/h)
Figure 2 – Temperature of reactor of reforming for varies air Feed molar flow
H2
Molar Flow of CO (kgmole/h)
120
CO
340 320
100
300
80
280
60
260 40 240 20
991
Molar Flow of H2 (kgmole/h)
Simulation and Optimization of H2 Production by Autothermal Reforming of Glycerol
220 0 300
400
500
600
700
800
Air - Molar Flow (kgmole/h)
Figure 3 - Molar flow of CO and H2 effluent for varies air feed molar flow. In Water Gas Shift Optimization , one case study was developed to optimized value of feed water molar flow to reduce concentration of CO through water gas shift reaction. Figure 3 shows the result of case study where the concentration of H2 and CO after water gas shift reactors was monitored. Water molar flow rate was optimized from 2000 to 8000 kg/h. As we can see from Figure 5.8, the H2 show an increasing slope and the increasing is a bit slower at 7500 kg/h. The optimum water molar flow rate was taken when hydrogen at its higher molar flow rate. So, the value of water molar flow rate that was chosen was 5500 kg/h. At this point, H2 produced the greatest flow rate and CO reduced the lowest flow rate.
Molar Flow of H2 (kgmole/h)
326
8
Hydrogen
324
CO
322
6
320
4
318 2
316
Molar Flow of CO (kgmole/h)
10 328
314 2000
3000
4000
5000
6000
7000
8000
0
Steam - Massa flow (kg/h)
Figure – 3 Molar flow of CO and H2 effluent for varies water feed molar flow. In the following, the results obtained for an autothermal reforming of glycerol system are presented. With the developed system models which are implemented in the HYSYS 3.1 process simulator, effluents from all reactors are simulated. In this model, the air to fuel ratio is set to 5.5 and the steam to fuel ratio is set to 3.5 In these conditions, 90% glycerol is converted to produce 34% hydrogen, 20.07% CO2 and 0.01% CO. Also, under these conditions, oxygen is 100% consumed. As we know, WGS reaction will convert CO into CO2 and hydrogen with the existence of steam.
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Therefore, the percentage of CO is decreasing, while the percentage of CO2 and hydrogen is increasing respectively. In the same time, the percentage of steam is decreasing.
4. CONCLUSIONS Basically, for 100 kmol/h of glycerol was inserted to the process and it produced about 327.37 kmol/h hydrogen. For the first reactor that is at the reforming reactor, hydrogen that produced after the optimization was 262.65 kmol/h. Optimization had been done for every reactor where by for the ATR reactor, we got 550 kmol/h of air for the highest hydrogen production and the lowest CO besides temperature around 672.9 °C. A number of important observations were noted based on the analysis of conclusions: 1. The simulation of hydrogen production plant model using autothermal reforming of methanol had been successfully developed using HYSYS 3.1. 2. The optimum A/F and S/F ratios are 5.5 and 3.5, respectively to produce hydrogen – 34.7 % (v/v), CO2 – 60% (v/v), and CO – 0.02% (v/v). 3. With optimum parameters above, 83.6% of fuel processor efficiency was achieved.
References Brown, L.F. A Comparative Study of Fuels for On-Board Hydrogen Production for Fuel-CellPowered Automobiles. International Journal of Hydrogen Energy. 26:381-397, 2001. Bühler, W. E. Dinjus, H.J. Ederer, A. Kruse, C. Mas, Ionic reactions and pyrolysis of glycerol as competing reaction pathways in near- and supercritical water, Journal of Supercritical Fluids 22 37–53, 2002. Hirai, T., N.O. Ikenaga, T. Miyake, and T. Suzuki. Production of hydrogen by steam reforming of glycerin on ruthenium catalyst. Energy and Fuels 9: 1761-1762, 2005. Lenz, B. and Aicher, T.. Catalytic Autothermal Reforming of Jet Fuel. Journal of Power Sources. 149:44-52, 2005. Prakash, C.B., “A Critical Review of Biodiesel as a Transportation Fuel in Canada”, Report to Transportation System Branch, Air Pollution Prevention Directorate, R gasification Biomass to produce Hydrogen Rich Gas”, Int. J. Hydrogen Energy 23, 551-557, 1998. Rapagna, S., N. Jand and U.P. Foscolo, “Catalytic Gasification Biomass to produce Hydrogen Rich Gas”, Int. J. Hydrogen Energy 23, 551-557 1998. Sadashiv M. Swami and Martin A. Abraham, Integrated Catalytic Process for Conversion of Biomass to Hydrogen, Energy & Fuels, 20, 2616-2622, 2006. Tyson K. S., “Biodiesel R & D”, Montana Biodiesel Workshop, October 8, 2003.