Table 1. Catalysts used for hydrogen production
|
Catalyst
|
Description
|
Reference
|
|
Ni/Zn/Al
|
The catalyst shows highest activity with low carbon deposits and high selectivity of carbon monoxide
|
(Nieva et al., 2014)
|
|
Ni/B/Al
|
Boron blocks the octahedral sites and reduces the nucleation of grapheme, thereby improving the stability and conversion
|
(Xu et al., 2009)
|
|
Ni/Si/Al
|
Nanoscale – nickel oxide and silicon oxide catalyst was prepared using sol-gel method, methane conversion efficiency was 95.7% and 3.8 moles of hydrogen per mole of methane was obtained
|
(Bej et al., 2013)
|
|
Ni/La/Al
|
Perovskite structure lanthanum and nickel catalyst was grown on alumina support, the catalyst activity was unaffected due to low deposits of carbon on the catalyst with higher hydrogen production rate
|
(Hufschmidt et al., 2010)
|
|
Pt/Ni/Mg/Al
|
Ni/Mg(Al)O catalyst was self-activated when doped with platinum and it also exhibited self-regeneration during reforming of methane
|
(Li et al., 2008)
|
|
Rh/Sr/Al
|
Substitution of Sr on hexaaluminate lattice tends to form stable plate like structure with high activity.
|
(McGuire et al., 2009)
|
|
Rh/Zr/Ce
|
The conversion rate of methane is high at low steam to carbon ratio and lower temperature
|
(Halabi et al., 2010)
|
|
Cu/Zn/Ce/Cr
|
ZrO2 promoted catalytic activity, CeO2 suppressed CO formation which resulted in 95% methanol conversion and no deactivation for 360 hours
|
(Zhang et al., 2013)
|
|
Ni/Ca/Zr
|
Addition of CaO for ethanol steam reforming resulted in reducing the Lewis acidity of zirconia thereby improving the resistance of the catalyst towards coking
|
(Nichele et al., 2014)
|
Table 2. Catalyst and feedstock for hydrogen production
|
Catalyst
|
Feedstock
|
Description
|
Reference
|
|
Silica Sand
|
Wood residue
|
Increase in reaction temperature and time increases the hydrogen production and small size of wood significantly enhances the H2 production
|
(Fremaux et al., 2015)
|
|
Bauxite
|
Wood pellets
|
The tar removal effect of bauxite was very high and gasification of char was increased to a great extent resulting in higher H2 production
|
(Berdugo Vilches et al., 2016)
|
|
Olivine & γ-Al2O3
|
Pinewood sawdust
|
The waste was steam gasified using both the catalysts, both catalysts significantly remove tar specially light and heavy PAHs, however, γ-alumina is slightly better in reforming hydrocarbons and eliminating tar
|
(Erkiaga et al., 2013)
|
|
Olivine (0.8)/dolomite (0.2)
|
Almond shells
|
The tar produced by steam reforming was two folds lower with a mixture of olivine and dolomite as compared to olivine alone
|
(Rapagnà et al., 2018)
|
|
Olivine, NiO/Al2O3
|
Almond shells
|
Steam gasification was carried out which resulted in 56% H2 production and overall 93.5% tar was converted
|
(Rapagnà et al., 2012)
|
Table 3 Strength and weakness of various hydrogen storage techniques (Jiang et al., 2014)
|
Hydrogen storage method
|
Strength
|
Weakness
|
|
Pressurized hydrogen
|
High speed of filling and low cost
|
Need high pressure vessel, low storage capacity, high energy consumption, poor safety and high cost of transportation
|
|
Cryogenic and liquid hydrogen
|
Small volume of storage container¸ high volumetric energy density
|
Strict requirement of storage and maintenance, high consumption of energy
|
|
Carbonaceous Materials
|
Convenient transportation, high capacity of storage, high specific surface area
|
High cost
|
|
Metal hydrides
|
High safety, stability and operability
|
Pulverizes easily, poor performance of hydrogen storage
|
|
Glass microspheres
|
High capacity of hydrogen storage
|
High cost, immature technology of hollow microsphere with high strength
|
|
Organic liquid
|
Reversible, safe transportation, high capacity of hydrogen storage
|
Catalysts are required for hydrogenation/dehydrogenation, low efficiency of dehydrogenation
|
Table 4. Properties of gaseous fuels
|
Property
|
LPG
|
CNG
|
Hydrogen
|
Biogas
|
|
Density at 1 atm. & 15 ℃ (kg/m3)
|
2.24
|
0.79
|
0.09
|
1.1
|
|
Flame Speed (cm/s)
|
38.25
|
34
|
265-325
|
25
|
|
Stoichiometric A/F
|
15.5
|
17.3
|
34.3
|
6
|
|
Flammability Limits (vol. % in air)
|
2.15-9.6
|
5.3-15
|
4-75
|
7.5-14
|
|
Octane Number
|
103-105
|
130
|
130
|
120
|
|
Auto Ignition Temperature (℃)
|
493-549
|
730
|
585
|
700
|
|
LCV at 1 atm. & 15℃ (kJ/kg)
|
46,000
|
50,000
|
120,000
|
5,000
|
Table 5. Summary of biomass feedstock for methanol production
|
Feedstock
|
Conversion Process
|
Remarks
|
Reference
|
|
Solid waste
|
Pyrolysis
|
185 kg of bio-methanol per metric ton of solid waste
|
(Güllü & Demirbaş, 2001)
|
|
Hazelnut shells
|
Pyrolysis
|
Bio-methanol yield 7.8% of dry and ash weight from 10 to 18% charred residues
|
|
Wood
|
Destructive Distillation
|
6 gallons bio-methanol (2%) per ton of wood
|
|
Biomass
|
Gasification
|
100 gallons of bio-methanol per ton of biomass
|
|
Wood
|
Gasification (biomass to liquid-MeOH)
|
47.7 (wt%) of bio-methanol from (400 tdry/d) wood
|
(Kumabe et al., 2008)
|
|
Biomass + steam + methane
|
Gasification
|
199.2 kg bio-methanol from 100 kg biomassþ1.2 kg steam/biomassþ 0.5 kg methane/kg biomass)
|
(Dong & Steinberg, 1997)
|
|
Wood + natural gas
|
Hynol gasification
|
101.5 MM gallon/year bio-methanol (38,494 kg/h) from 2000 short ton per day of wood (75,598 kg/h)
|
|
Conditioning bio-syngas + biomass char of rice husk
|
Gasification
|
1.32 kg/ (kg catalyst h) of bio-methanol from 120 kg/h oil rice husk
|
(Nakagawa et al., 2007)
|
Table 6. Summary of plants on industrial scale or demonstration scale for producing methanol from CO2 (Sarp et al., 2021)
|
Organization
|
Location
|
Capacity (tpa)
|
Temperature (°C)
|
Pressure (Psi)
|
|
NIRE and RITE
|
Kyoto, Japan
|
18
|
250
|
725
|
|
Lurgi AG
|
Frankfurt, Germany
|
-
|
260
|
870
|
|
Camere process
|
Seoul, South Korea
|
73
|
250
|
400
|
|
Carbon Recycling International
|
Grindavik, Ireland
|
4000
|
225
|
725
|
|
Mitsui Chemicals
|
Osaka, Japan
|
100
|
250
|
725
|
|
Air Company
|
Brooklyn, USA
|
32
|
250
|
750
|
Table 7. Comparison of fuel properties diesel, gasoline, biodiesel, ethanol and methanol (Çelebi & Aydın, 2019)
|
Fuel Property
|
Diesel
|
Gasoline
|
Ethanol
|
Methanol
|
|
Formula
|
C10–26
|
C5–12
|
C2H5OH
|
CH3OH
|
|
Oxygen content [mass %]
|
0
|
0
|
34.8
|
50
|
|
Density [kg/m3 at 20oC]
|
834
|
740
|
790
|
790
|
|
Viscosity at 40 °C [mPa s]
|
2.9
|
0.29
|
1.1
|
0.59
|
|
Stoichiometric air/fuel ratio
|
14.5
|
14.6
|
9
|
6.45
|
|
Lower calorific value
(MJ/kg)
|
43
|
44
|
26
|
19
|
|
Higher calorific value (MJ/kg)
|
45.8
|
46.6
|
28.5
|
22.5
|
|
Freezing point at 1 bar [°C]
|
-40
|
-57
|
-80
|
-97.7
|
|
Boiling point at 1 bar [°C]
|
175-360
|
30-220
|
78.4
|
64.5
|
|
Flash point (ºC)
|
55
|
-45
|
13
|
11
|
|
Auto-ignition temperature (ºC)
|
220-260
|
228–470
|
422
|
463.8
|
|
Research octane number (RON)
|
<0
|
80-98
|
108
|
107
|
|
Motor octane number (MON)
|
<0
|
81-84
|
92
|
92
|
|
Cetane number
|
40-55
|
0-10
|
6
|
<5
|
|
Specific heat (20ºC) (kJ/kg K)
|
1.9
|
2.3
|
-
|
2.55
|
|
Heat of vaporization [MJ/kg]
|
270
|
310
|
910
|
1109
|
Table 8. Merits and demerits of using neat methanol in an SI engine
|
Merits
|
Demerits
|
|
Minimizing the unwanted issues of knocking phenomenon. Methanol also provides flexibility to work at higher compression ratio, resulting in improved efficiency in SI engines.
|
Indigent self-ignition properties resulting in long ignition delay.
|
|
Exhaust emissions are soot free, therefore providing cleaner (soot-free) combustion.
|
Mixing quality with conventional fuel is poor, resulting in difficulties of cold starting of engine.
|
|
Improved fuel economy, flexibility of operating at lean mixtures and reduced harmful emissions of NO, HC and CO
|
Corrosion of engine parts on longer term usage
|
|
Higher latent heat of vaporization, imparts lower combustion temperature and results in lower NO emissions
|
Evaporation in fuel lines (vapour locks)
|
|
Higher volatility providing better fuel distribution of air-fuel mixtures among the cylinders
|
Poor oxidation stability and degradation of oil lubrication properties resulting from low viscosity
|
Table 9. Cost for developing new hydrogen production, delivery and refueling station infrastructure (Ogden et al., 1999)
|
|
Centralized production via natural gas steam reforming with liquid hydrogen delivery
|
Centralized production via natural gas steam reforming with pipeline delivery
|
Onsite reforming of natural gas with conventional steam methane reformer
|
Onsite reforming of natural gas with fuel cell methane reformer
|
Onsite advanced electrolysis using off-peak power
|
|
Centralized hydrogen production
|
US$100 million for reformer+ US$200 million for liquefier+ liquid hydrogen storage
|
US$170 million for reformer+ compressor for hydrogen
|
|
|
|
|
Hydrogen distribution
|
80 liquid hydrogen trucks each with 3ton capacity, each making two deliveries in a day = US$40 million
|
600 km pipeline amounts to US$380 million (at US$1 million/mile)
|
|
|
|
|
153 million scf H2 per day refuelling stations each serving 654 cars per day
|
US$104 million (US$0.7 million/station)
|
US$260 million (US$1.7 million/station)
|
US$830 million (US$5.4 million/station)
|
US$516 million (US$3.4 million/station)
|
US$870 million (US$5.7 million/station)
|
|
Total
|
US$440 million
|
US$810 million
|
US$830 million
|
US$516 million
|
US$870 million
|
|
Infrastructure cost per car
|
US$312
|
US$574
|
US$587
|
US$370
|
US$620
|
Table 10. Capital cost of methanol infrastructure (Ogden et al., 1999)
|
|
Capital Cost
|
Cars Served
|
Capital cost per car (US$ per car)
|
|
Refueling station conversion (1100 gal per day)
|
US$45,000
|
1309
|
34
|
|
Marine terminal conversion
|
US$18.5/bbl storage capacity; 6500 bbl (minimum)
|
2.4 cars/bbl of storage capacity; 15,400 cars (minimum)
|
8
|
|
Tanker shipping capacity
|
US$200/DWT for a new 250,000 DWT ultra large tanker
|
3–15 million cars (if tanker makes 10–50 deliveries in a year)
|
3-17
|
|
New production capacity
|
US$880–1540 million (10, 000 metric tons/day)
|
4 million cars
|
220-385
|
|
US$330–570 million (2500 metric tons/day)
|
1 million cars
|
330-570
|