6. Light hydrocarbons (LHs)

CnHm þ

48 Advances In Hydrogen Generation Technologies

improvement brought by the membrane [43].

low pressures, and high nCO2/CnHm molar.

5.2. Pyrolysis of hydrocarbon

5.1.4. Dry reforming

1 2

of oxygenated chemicals [47]. The dry reforming reaction is:

CnHm <sup>þ</sup> n CO<sup>2</sup> ! <sup>1</sup>

nH2O þ

1 4

nO<sup>2</sup> ! nCO þ

When methane is autothermally reformed at 700�C inlet temperature and the proper ratios of steam to carbon and oxygen to carbon, a thermal efficiency of 60–75% and maximum hydrogen yield of about 2.8 are achieved [42]. The investment cost is about 50% lower than coal gasification. A small improvement is reported when the ATR reactor is combined with a Pd membrane. The high operating temperature of 900�C needed by the system ruins the efficiency

The dry reforming is a chemical process that consists of converting hydrocarbon and carbon dioxide, considered as one of the world's most abundant greenhouse gases to synthesis gas with a proper H2/CO molar ratio [46]. As a result, this process has the potentials to alleviate the environmental challenges related to greenhouse gases emissions and to transform biogas and natural gas to synthesis gas. Furthermore, the produced H2/CO ratio synthesis gas is suitable for the production of hydrocarbons via Fischer-Tropsch synthesis, in addition to the synthesis

> 2 m

Being an extremely endothermic reaction, dry reforming requires high operating temperatures, usually in the range of 900–1273 K, to achieve the desired conversion levels. The forward reaction is favored at low pressures as dictated by stoichiometry. Additionally, it has been observed that an nCO2/CnHm molar ratio higher than the stoichiometric requirement of unity can also provide high synthesis gas yields. The positive effects of high reaction temperatures,

The pyrolysis of hydrocarbon is a famous method where hydrogen solely comes from the

Light liquid hydrocarbons having boiling points 200�C are decomposed thermo-catalytically to generate elemental carbon and hydrogen, however, dealing with residual fractions having boiling temperatures above 350�C, the production of hydrogen requires hydrogasification and cracking of methane. The direct reduction of carbon content in the natural gas known as often de-carbonization, which constitutes mainly methane, is performed at 980�C temperature and atmospheric pressure in the environment, where there is no water and air. Furthermore, pyrolysis does not involve CO2 removal steps and water gas shift. Carbon control and

1 2

hydrocarbon subjected to thermal decomposition via the following universal reaction:

CnHm ! nC þ

1 2 n þ 1 2 m 

H<sup>2</sup> (7)

H<sup>2</sup> þ 2nCO (8)

mH2 (9)

Hydrocarbons, as their name denotes, are compounds of hydrogen and carbon. They represent one of the vital classes of organic chemistry. They exist in gaseous states such as propane and methane, a liquid state like benzene and hexane, and solid state as paraffin wax, polystyrene, naphthalene, and polyethylene.

Hydrocarbons are classified into:


Hydrocarbons are a primary energy source for current civilizations. The predominant use of hydrocarbons is as a combustible fuel source. In their solid form, hydrocarbons take the form of asphalt (bitumen) [49]. Methane and ethane are gaseous at ambient temperatures and cannot be readily liquefied by pressure alone. Propane is however easily liquefied and exists in 'propane bottles' mostly as a liquid. Butane is so easily liquefied that it provides a safe,


anthropogenic methane emissions came from sources like agriculture, coal mines, landfill, oil and natural gas systems and waste water. Mobile sources in specific are famous to give meaningfully to urban hydrocarbon and nitrogen oxide levels. For instance the vehicle exhaust accounts for most of the non-methane hydrocarbon concentrations in metropolitan cities [51–53].

Hydrogen Production from Light Hydrocarbons http://dx.doi.org/10.5772/intechopen.76813 51

Steam reforming of liquefied petroleum gas (LPG) is a practical choice for producing hydrogen in isolated regions where there is no pipeline natural gas supply. The most common LPG gases include propane, butane (n-butane) and isobutane (i-butane), as well as mixtures of these gases. Fuel processing converts LPG into hydrogen and carbon dioxide. Lopez-Ortiz et al. elaborated the utilization of cobalt tungstate in a chemical looping partial oxidation of methane process to generate syngas [54]. They carried out simulations and thermodynamic analysis. Results acquired indicated no carbon formation and syngas yield (89.6%) were calculated. Wang et al. investigated the autothermal reforming of LPG in a fixed-bed reactor by changing essential parameters like steam-to-carbon ratio (S/C), the oxygen-to-carbon ratio (O/C), reforming temperature, and catalyst [55]. It was established that temperature, S/C, and O/C were the most key parameters for fuel conversion and lowering carbon deposition. Similarly, steam reforming is applied to convert LPG to hydrogen using Rh, Ru, Pt, and other noble metal catalysts. For instance, Laosiripojana et al., used Ni- and Rh-based catalysts supported on GdCeO2 (CGO) and Al2O3 in steam reforming of LPG at 750–900C [56]. They obtained that Rh/CeO2 catalyst gave the highest H2 yield. Steam reforming of LPG employing nickel-based perovskites (La-Ni-O) partly replaced with cobalt was examined [57]. The suitable selection of water/LPG feed ratio together with the proper Co/Ni ratio in the synthesis of perovskite precursors was vital to retain

the catalyst active during LPG steam reform and hence the hydrogen production.

tivity as a function of temperature and steam to carbon ratio (S/C).

A broad experimental study of steam reforming (SR) of alkane components: methane, ethane, propane, butane, and natural gas for the catalytic conversion over a Rh-based catalyst was carried out and compared to numerically predicted conversion and selectivity [58]. The result established a mechanism for predicting product distribution in steam reforming of natural gas mixtures with varying compositions. Likewise, the developed simulation, permit the numerical calculation of chemical species profiles and surface coverage within catalytic monoliths. Steam reforming of ethane, propane, and butane display virtually same conversion and selec-

Rhodium-based catalyst with different Rh content (1, 2.5 and 5 wt. %) and high surface area alumina support were tested for steam reforming of propane [59]. All catalysts exhibited complete conversion at 750C with hydrogen selectivity over 98% and high stability for more than 140 hours' time on stream. In the work of Ferrandon et al., Mono-metallic nickel and rhodium catalysts and bimetallic Ni-Rh catalysts supported on La-Al2O3, CeZrO2, and CeMgOx were arranged and assessed for catalyzing the steam and autothermal reforming of n-butane [60]. The bimetallic Ni-Rh supported on La-Al2O3 catalysts with low weight loading of rhodium showed higher H2 yields than Ni or Rh alone. The Ni-Rh/CeZrO2 catalyst

6.2. Production of hydrogen from alkanes

6.1. Production of hydrogen from liquefied petroleum gas

Table 1. Simple hydrocarbons and their variations.

volatile fuel for small pocket lighters. Pentane (C5H12) is a clear liquid at room temperature, commonly used in chemistry and industry as a powerful nearly odorless solvent of waxes and high molecular weight organic compounds, including greases. Hexane (C6H14) is also a widely used non-polar, non-aromatic solvent, as well as a significant fraction of common gasoline. The C<sup>6</sup> through C<sup>10</sup> alkanes, alkenes and isomeric cycloalkanes are the chief components of gasoline, naphtha, jet fuel and specialized industrial solvent mixtures. Hydrocarbons with low molecular weight such as methane, ethane, propane and ethane are termed as light hydrocarbons (LHs). Light hydrocarbons are the largest petroleum fraction which in between Cl and C9. They are catagenic products, formed between 75 and 140C. The higher hydrocarbons are too stable to generate the LHs at these temperatures. Additionally, LHs are different from cracking products [50]. Many are structurally like bio-precursors. Basically, all isomers are found within the alkanes, cycloalkanes and aromatics with no visible preference for natural structures. It is improbable that the LHs are formed without support. The LHs constitute well over 50% of the carbon in petroleum. They seem to be a random mixture of classes (isoalkanes, cyclopentanes, cyclohexanes, and aromatics). For instance, the gasoline fraction of different crudes may be branded by identifying the relative amounts of the following five classes of hydrocarbons: normal paraffins, isoparaffins, alkylcyclopentanes, alkylcyclohexanes, and aromatics. Of analogous significance to hydrogen, is the production of its mixture with carbon monoxide (H2 + CO), normally named synthesis gas or syngas, which is a valuable raw material for numerous industrial uses. The significant natural sources of light hydrocarbons comprise leakage from oil and gas reservoirs and anaerobic production of methane. There are some reports of low molecular weight hydrocarbons in open ocean water. The coastal waters act as a source for atmospheric methane. The vital man-derived sources of methane in the coast are ports with their accompanying shipping and industrial activity, offshore petroleum drilling and production operations, and open ocean shipping activity. In 2010 almost, 50% of global anthropogenic methane emissions came from sources like agriculture, coal mines, landfill, oil and natural gas systems and waste water. Mobile sources in specific are famous to give meaningfully to urban hydrocarbon and nitrogen oxide levels. For instance the vehicle exhaust accounts for most of the non-methane hydrocarbon concentrations in metropolitan cities [51–53].

### 6.1. Production of hydrogen from liquefied petroleum gas

Steam reforming of liquefied petroleum gas (LPG) is a practical choice for producing hydrogen in isolated regions where there is no pipeline natural gas supply. The most common LPG gases include propane, butane (n-butane) and isobutane (i-butane), as well as mixtures of these gases. Fuel processing converts LPG into hydrogen and carbon dioxide. Lopez-Ortiz et al. elaborated the utilization of cobalt tungstate in a chemical looping partial oxidation of methane process to generate syngas [54]. They carried out simulations and thermodynamic analysis. Results acquired indicated no carbon formation and syngas yield (89.6%) were calculated. Wang et al. investigated the autothermal reforming of LPG in a fixed-bed reactor by changing essential parameters like steam-to-carbon ratio (S/C), the oxygen-to-carbon ratio (O/C), reforming temperature, and catalyst [55]. It was established that temperature, S/C, and O/C were the most key parameters for fuel conversion and lowering carbon deposition. Similarly, steam reforming is applied to convert LPG to hydrogen using Rh, Ru, Pt, and other noble metal catalysts. For instance, Laosiripojana et al., used Ni- and Rh-based catalysts supported on GdCeO2 (CGO) and Al2O3 in steam reforming of LPG at 750–900C [56]. They obtained that Rh/CeO2 catalyst gave the highest H2 yield. Steam reforming of LPG employing nickel-based perovskites (La-Ni-O) partly replaced with cobalt was examined [57]. The suitable selection of water/LPG feed ratio together with the proper Co/Ni ratio in the synthesis of perovskite precursors was vital to retain the catalyst active during LPG steam reform and hence the hydrogen production.

#### 6.2. Production of hydrogen from alkanes

volatile fuel for small pocket lighters. Pentane (C5H12) is a clear liquid at room temperature, commonly used in chemistry and industry as a powerful nearly odorless solvent of waxes and high molecular weight organic compounds, including greases. Hexane (C6H14) is also a widely used non-polar, non-aromatic solvent, as well as a significant fraction of common gasoline. The C<sup>6</sup> through C<sup>10</sup> alkanes, alkenes and isomeric cycloalkanes are the chief components of gasoline, naphtha, jet fuel and specialized industrial solvent mixtures. Hydrocarbons with low molecular weight such as methane, ethane, propane and ethane are termed as light hydrocarbons (LHs). Light hydrocarbons are the largest petroleum fraction which in between Cl and C9. They are catagenic products, formed between 75 and 140C. The higher hydrocarbons are too stable to generate the LHs at these temperatures. Additionally, LHs are different from cracking products [50]. Many are structurally like bio-precursors. Basically, all isomers are found within the alkanes, cycloalkanes and aromatics with no visible preference for natural structures. It is improbable that the LHs are formed without support. The LHs constitute well over 50% of the carbon in petroleum. They seem to be a random mixture of classes (isoalkanes, cyclopentanes, cyclohexanes, and aromatics). For instance, the gasoline fraction of different crudes may be branded by identifying the relative amounts of the following five classes of hydrocarbons: normal paraffins, isoparaffins, alkylcyclopentanes, alkylcyclohexanes, and aromatics. Of analogous significance to hydrogen, is the production of its mixture with carbon monoxide (H2 + CO), normally named synthesis gas or syngas, which is a valuable raw material for numerous industrial uses. The significant natural sources of light hydrocarbons comprise leakage from oil and gas reservoirs and anaerobic production of methane. There are some reports of low molecular weight hydrocarbons in open ocean water. The coastal waters act as a source for atmospheric methane. The vital man-derived sources of methane in the coast are ports with their accompanying shipping and industrial activity, offshore petroleum drilling and production operations, and open ocean shipping activity. In 2010 almost, 50% of global

(triple bond)

—— —— Methane — — Ethyne Ethene Ethane Propadiene Cyclopropane Propyne Propene Propane Butadiene Cyclobutane Butyne Butene Butane Pentadiene Cyclopentane Pentyne Pentene Pentane Hexadiene Cyclohexane Hexyne Hexene Hexane Heptadiene Cycloheptane Heptyne Heptene Heptane Octadiene Cyclooctane Octyne Octene Octane Nonadiene Cyclononane Nonyne Nonene Nonane Decadiene Cyclodecane Decyne Decene Decane Undecadiene Cycloundecane Undecyne Undecene Undecane

Alkene (double bond) Alkane (single bond)

Alkadiene Cycloalkane Alkyne

50 Advances In Hydrogen Generation Technologies

Table 1. Simple hydrocarbons and their variations.

A broad experimental study of steam reforming (SR) of alkane components: methane, ethane, propane, butane, and natural gas for the catalytic conversion over a Rh-based catalyst was carried out and compared to numerically predicted conversion and selectivity [58]. The result established a mechanism for predicting product distribution in steam reforming of natural gas mixtures with varying compositions. Likewise, the developed simulation, permit the numerical calculation of chemical species profiles and surface coverage within catalytic monoliths. Steam reforming of ethane, propane, and butane display virtually same conversion and selectivity as a function of temperature and steam to carbon ratio (S/C).

Rhodium-based catalyst with different Rh content (1, 2.5 and 5 wt. %) and high surface area alumina support were tested for steam reforming of propane [59]. All catalysts exhibited complete conversion at 750C with hydrogen selectivity over 98% and high stability for more than 140 hours' time on stream. In the work of Ferrandon et al., Mono-metallic nickel and rhodium catalysts and bimetallic Ni-Rh catalysts supported on La-Al2O3, CeZrO2, and CeMgOx were arranged and assessed for catalyzing the steam and autothermal reforming of n-butane [60]. The bimetallic Ni-Rh supported on La-Al2O3 catalysts with low weight loading of rhodium showed higher H2 yields than Ni or Rh alone. The Ni-Rh/CeZrO2 catalyst exhibited higher performance and no coke formation, in comparison to similar metals on other supports. Hydrogen was produced from butane steam reforming using Ni/Ag loaded MgAl2O4 catalyst to substitute the conventional fast catalytic deactivation and lower H2 production from the hydrocarbon steam-reforming reaction [61]. The Ag-loaded catalyst showed considerably higher reforming reactivity than Ni/MgAl2O4 catalyst. The silvercontaining catalyst diminished the carbon formation and boosted the hydrogen product and selectivity. The production of H2 was enhanced up to 68% at 700�C for 1 h and this high efficiency sustained for up to 53 h.

CH<sup>4</sup> \$ C þ 2H<sup>2</sup> (13)

Hydrogen Production from Light Hydrocarbons http://dx.doi.org/10.5772/intechopen.76813 53

CO<sup>2</sup> þ 2H<sup>2</sup> \$ C þ 2H2O (14)

2COþ \$ C þ CO<sup>2</sup> (15)

CO þ H<sup>2</sup> \$ C þ H2O (16)

Methane (CH4) is a light hydrocarbon and the most important component of natural gas. Methane is also a strong and plentiful greenhouse gas (GHG), which makes it a significant contributor to climate change. Methane like other LHs can be converted to hydrogen using different methods as mentioned. The natural gas comprising C1, C2, C3, and C4+ have been widely used to produce hydrogen. As presented in Table 2, methane is a primary component

Catalytic carbon dioxide reforming of methane (CO2 reforming of CH4), also called dry reforming of methane to distinguish this process from steam reforming, has attracted rigorous research interest during the last decades. The interest is ascribed to the fact that CO2 reforming

The equilibrium conversion and the equilibrium product composition are influenced by the reaction temperature, pressure, initial reactant ratio, and the content of the inert gas. Nevertheless, catalysts must be employed to allow the reaction to take place in reasonable kinetics. Ni catalyst is found suitable for this reaction. Aluminum oxide (Al2O3), particularly γ-Al2O3, is one of the best generally used catalyst support materials for CO2 reforming of CH4. Liao and Horng studied methane dry reforming to generate synthesis gas [68]. Their work concentrated

CO2ð Þþ g CH4ð Þ!g 2H2ð Þþ g 2CO gð ÞΔH298<sup>K</sup> ¼ þ247KJ=mole (17)

Wet Dry

6.4. Production of hydrogen from methane

in natural gas followed by ethane and propane [67].

of CH4 mitigates carbon emissions. The reaction is endothermic:

Elements Volumetric composition (%)

Table 2. Universal composition of dry and wet natural gas.

Methane 84.6 96.0 Ethane 6.4 2.00 Propane 5.3 0.60 Isobutane 1.2 0.18 n-butane 1.4 0.12 Isopentane 0.4 0.14 n-Pentane 0.2 0.06 Hexanes 0.4 0.10 Heptanes 0.1 0.80

Mesoporous nanocrystalline Ni/Al2O3 catalysts were used to examine the Partial oxidation (POX) of methane, ethane, and propane [62]. Different feed conditions were considered during the study. 5 wt. % Ni/Al2O3 catalysts displayed the maximum catalytic activity in the temperature range of 500–700�C. The catalyst was substantially stable for 48 h time on stream in methane partial oxidation. Moreover, increased carbon deposition on the catalysts was observed when ethane and propane in stoichiometric feed ratio were considered. Alternatively, the performance of CO2-reforming of methane over mesoporous Co-Ni/SBA-15-x (x = Mg, La, and Sc) was tested in continuous fixed bed at 700–800�C reaction temperature [63]. When the catalyst support was modified by adding Mg and Sc, the CH4 conversion was improved markedly by 28 and 26%, respectively at 700�C higher than the corresponding bare SBA-15 supported catalysts. TEM and TGA/GTA characterizations of spent catalyst established that the coke resistance was considerably upgraded as a result of the support alteration, leading to the formation of amorphous carbon. Consequently, Co-Ni/SC-SBA-15 catalyst remarkably promoted the stability and catalytic activity to produce synthesis gas.

#### 6.3. Production of hydrogen from ethane

With the increased production of shale gas through a new drilling technology of hydraulic fracturing significant attention has been paid to the utilization of ethane which accounts for about 7% of shale gas [64]. Jeong et al. proposed a pathway for using ethane to generate hydrogen [65]. The investigators performed the analysis of membrane reactor using techno-economic analysis and process simulation using Aspen HYSYS® for ethane steam reforming. The process simulation indicated high H2 selectivity. In ethane steam reforming, synthesis gas is produced as:

$$\rm C\_2H\_6 + 2H\_2O \to 5H\_2 + 2CO \tag{10}$$

Alternatively, Veranitisagul et al. studied ceria and gadolinia doped ceria catalysts to produce syngas from ethane at the temperature range of 800–900�C via the steam reforming reaction [66]. The catalytic activity was enhanced with the addition of 0.15 Gd. It could generate a substantial amount of hydrogen and the carbon formation that deactivates at high temperature was prevented. Hypothetically, the carbon formation could take place through the reforming of ethane, as result of these reactions:

$$\text{C}\_2\text{H}\_6 \leftrightarrow 2\text{C} + 3\text{H}\_2\tag{11}$$

$$\text{C}\_2\text{H}\_4 \leftrightarrow 2\text{C} + 2\text{H}\_2\tag{12}$$

$$\text{CH}\_4 \leftrightarrow \text{C} + 2\text{H}\_2\tag{13}$$

$$\text{C} \text{CO}\_2 + 2\text{H}\_2 \leftrightarrow \text{C} + 2\text{H}\_2\text{O} \tag{14}$$

$$\text{'} \text{'} \text{CO} + \leftrightarrow \text{'} + \text{CO}\_2 \tag{15}$$

$$\text{CO} + \text{H}\_2 \leftrightarrow \text{C} + \text{H}\_2\text{O} \tag{16}$$

#### 6.4. Production of hydrogen from methane

exhibited higher performance and no coke formation, in comparison to similar metals on other supports. Hydrogen was produced from butane steam reforming using Ni/Ag loaded MgAl2O4 catalyst to substitute the conventional fast catalytic deactivation and lower H2 production from the hydrocarbon steam-reforming reaction [61]. The Ag-loaded catalyst showed considerably higher reforming reactivity than Ni/MgAl2O4 catalyst. The silvercontaining catalyst diminished the carbon formation and boosted the hydrogen product and selectivity. The production of H2 was enhanced up to 68% at 700�C for 1 h and this high

Mesoporous nanocrystalline Ni/Al2O3 catalysts were used to examine the Partial oxidation (POX) of methane, ethane, and propane [62]. Different feed conditions were considered during the study. 5 wt. % Ni/Al2O3 catalysts displayed the maximum catalytic activity in the temperature range of 500–700�C. The catalyst was substantially stable for 48 h time on stream in methane partial oxidation. Moreover, increased carbon deposition on the catalysts was observed when ethane and propane in stoichiometric feed ratio were considered. Alternatively, the performance of CO2-reforming of methane over mesoporous Co-Ni/SBA-15-x (x = Mg, La, and Sc) was tested in continuous fixed bed at 700–800�C reaction temperature [63]. When the catalyst support was modified by adding Mg and Sc, the CH4 conversion was improved markedly by 28 and 26%, respectively at 700�C higher than the corresponding bare SBA-15 supported catalysts. TEM and TGA/GTA characterizations of spent catalyst established that the coke resistance was considerably upgraded as a result of the support alteration, leading to the formation of amorphous carbon. Consequently, Co-Ni/SC-SBA-15 catalyst remarkably

With the increased production of shale gas through a new drilling technology of hydraulic fracturing significant attention has been paid to the utilization of ethane which accounts for about 7% of shale gas [64]. Jeong et al. proposed a pathway for using ethane to generate hydrogen [65]. The investigators performed the analysis of membrane reactor using techno-economic analysis and process simulation using Aspen HYSYS® for ethane steam reforming. The process simulation

Alternatively, Veranitisagul et al. studied ceria and gadolinia doped ceria catalysts to produce syngas from ethane at the temperature range of 800–900�C via the steam reforming reaction [66]. The catalytic activity was enhanced with the addition of 0.15 Gd. It could generate a substantial amount of hydrogen and the carbon formation that deactivates at high temperature was prevented. Hypothetically, the carbon formation could take place through the reforming of

C2H<sup>6</sup> þ 2H2O ! 5H<sup>2</sup> þ 2CO (10)

C2H<sup>6</sup> \$ 2C þ 3H<sup>2</sup> (11)

C2H<sup>4</sup> \$ 2C þ 2H<sup>2</sup> (12)

indicated high H2 selectivity. In ethane steam reforming, synthesis gas is produced as:

promoted the stability and catalytic activity to produce synthesis gas.

efficiency sustained for up to 53 h.

52 Advances In Hydrogen Generation Technologies

6.3. Production of hydrogen from ethane

ethane, as result of these reactions:

Methane (CH4) is a light hydrocarbon and the most important component of natural gas. Methane is also a strong and plentiful greenhouse gas (GHG), which makes it a significant contributor to climate change. Methane like other LHs can be converted to hydrogen using different methods as mentioned. The natural gas comprising C1, C2, C3, and C4+ have been widely used to produce hydrogen. As presented in Table 2, methane is a primary component in natural gas followed by ethane and propane [67].

Catalytic carbon dioxide reforming of methane (CO2 reforming of CH4), also called dry reforming of methane to distinguish this process from steam reforming, has attracted rigorous research interest during the last decades. The interest is ascribed to the fact that CO2 reforming of CH4 mitigates carbon emissions. The reaction is endothermic:

$$\text{CO}\_2(\text{g}) + \text{CH}\_4(\text{g}) \rightarrow 2\text{H}\_2(\text{g}) + 2\text{CO}(\text{g})\\\Delta\text{H}\_{298\text{K}} = +247\text{K}/\text{mole} \tag{17}$$

The equilibrium conversion and the equilibrium product composition are influenced by the reaction temperature, pressure, initial reactant ratio, and the content of the inert gas. Nevertheless, catalysts must be employed to allow the reaction to take place in reasonable kinetics. Ni catalyst is found suitable for this reaction. Aluminum oxide (Al2O3), particularly γ-Al2O3, is one of the best generally used catalyst support materials for CO2 reforming of CH4. Liao and Horng studied methane dry reforming to generate synthesis gas [68]. Their work concentrated


Table 2. Universal composition of dry and wet natural gas.

on the heat recovery of the designed reformers. An oven was employed for the simulation of the heat recovery. The results specified that the oven temperature is proportional to the reforming reaction temperature and hence promote the energy of the reformer. When the energy of reformer was increased the synthesis gas production enhanced and efficiency of reforming and CO2 conversion was obviously raised. The production of hydrogen and carbon from the catalytic decomposition of methane via iron catalyst was explored [69]. The

investigation covered the utilization of alumina supported catalysts over various iron loadings. Multiwall nanotubes were formed and as the % loading of Fe was increased, the hydrogen yield increased. When 60% Fe/Al2O3 catalyst was employed, the highest H2 yield of 77.2% was acquired. Similarly, mono-, bi- and tri-metallic catalysts obtained from iron-nickel-cobalt supported over alumina was examined for the decomposition of methane to hydrogen and value-added carbon. The catalytic activity of 30 wt. % Fe and 15 wt.% Co displayed the highest performance overall investigated catalysts. Figure 4 illustrates the hydrogen yield versus time on stream (TOS). It is apparent that the gas hourly space velocity (GHSV) has some effect on the hydrogen yield [70]. Table 3 reviews the technologies along with their reaction temperatures and percentage of hydrogen yield. It is important to note that hydrogen yield depends on

Hydrogen Production from Light Hydrocarbons http://dx.doi.org/10.5772/intechopen.76813 55

Currently, about 1/5 of global energy is utilized as electricity, whereas 80% is utilized as fuel. Hydrogen energy is a clean and alternative energy that has been suggested as the energy carrier of the future. Solar-driven microalga hydrogen production is both a favorable and inspiring biotechnology, which play a significant role in the global drive to decrease GHG emissions. One of the major barriers with regard to the hydrogen economy is its production cost and inefficient storage methods, which need to be resolved. Current research efforts are focused on strain improvement by systems metabolic engineering and finding suitable conditions to increase the levels of hydrogen production. In the near future, it may be possible to perform knockouts and insertions based on the data available by modeling previous studies. The advent of synthetic biology necessitates such models since it aims at standardizing biology, which should give predicted responses. With all these advancements, the commercial feasibility of H2 production may rely on efficient production strategies with elevated yield, well-organized transport and storage systems ensuring the secured supply of hydrogen. Moreover, the prospect of light hydrocarbon hydrogen production is determined by the research advances such as enhancement of productivity through catalytic engineering and the advance of chemical reactors, the economic attentions like the price of fossil fuels, social appreciation, and use of hydrogen energy systems in our society. Today, hydrogen is being used to power a fleet of busses in some countries. More industries will accept hydrogen energy when a renewable economically viable process of hydrogen production is achieved. Last but not least, the integrated effort of both scientists and engineers is needed to fully implement hydrogen energy as the energy for the future. Mass hydrogen production is the foundation for the transition to a "hydrogen economy", which has the potential

the type of catalyst, pretreatment and operating conditions [71–78].

to enable the development of distributed power generation networks [79].

The global crisis of fossil fuels has greatly stimulated worldwide interest to develop sustainable sources of energy carriers. Light hydrocarbons can be used as a potential source of hydrogen energy due to their inherent capacity to decompose the hydrocarbon into H2 using

7. Future perspective

8. Conclusions

Figure 4. Stability performances in terms of H2 yield (%) over 15Co-30Fe/Al catalysts as a function of TOS at 700C at different GHSVs.


Table 3. Summary of hydrogen yield from methane for various hydrogen production techniques.

investigation covered the utilization of alumina supported catalysts over various iron loadings. Multiwall nanotubes were formed and as the % loading of Fe was increased, the hydrogen yield increased. When 60% Fe/Al2O3 catalyst was employed, the highest H2 yield of 77.2% was acquired. Similarly, mono-, bi- and tri-metallic catalysts obtained from iron-nickel-cobalt supported over alumina was examined for the decomposition of methane to hydrogen and value-added carbon. The catalytic activity of 30 wt. % Fe and 15 wt.% Co displayed the highest performance overall investigated catalysts. Figure 4 illustrates the hydrogen yield versus time on stream (TOS). It is apparent that the gas hourly space velocity (GHSV) has some effect on the hydrogen yield [70]. Table 3 reviews the technologies along with their reaction temperatures and percentage of hydrogen yield. It is important to note that hydrogen yield depends on the type of catalyst, pretreatment and operating conditions [71–78].
