Chapter 10: "Adsorption of Methane in porous materials as the basis for the storage of Natural Gas"

C. SOLAR; A. GARCÍA BLANCO; A. VALLONE; K. SAPAG

Natural Gas

SCIYO Publishing

Año: 2010; p. 1 - 40

The use of Natural Gas (NG) as a fundamental source of energy is out of question, both at industrial and home level as well as for the production of another kind of energy, like electricity. This fact has inducted a constant search for new natural resources, existing at the moment important world natural gas reserves, which develop its use in several kinds of applications. By another way, the political and economics changes and the important pollutants effects produced by the liquid fuels, specially in its use for automobiles, has promoted the search for alternative resources, where the NG has played an outstanding roll, as Natural Gas Vehicles (NGV). The NG as fuel in mobile units presents a series of environmental benefits, compared to liquid fuels, as the reduction in the emission of contaminants and the minor costs in the maintenance of the vehicles. Compared to liquid fuels, the NGV presents up to 76% less of CO emissions; up to 75% less in NOx emissions; 88% less in hydrocarbons emissions and up to 30% less for CO2 emissions. The disadvantages of the NGV use are centered in the storage of the NG, due to its characteristics. One of the properties that difficult the NG storage is its low volumetric energy density, where an increase in its density is necessary to compete against the traditional fuels. In normal conditions of temperature and pressure (NTP), the yield (Y) of the NG in mobiles (mileage per unit fuel tank volume), directly related to their volumetric density, is about 0.12% respect to gasoline. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. The NG as fuel in mobile units presents a series of environmental benefits, compared to liquid fuels, as the reduction in the emission of contaminants and the minor costs in the maintenance of the vehicles. Compared to liquid fuels, the NGV presents up to 76% less of CO emissions; up to 75% less in NOx emissions; 88% less in hydrocarbons emissions and up to 30% less for CO2 emissions. The disadvantages of the NGV use are centered in the storage of the NG, due to its characteristics. One of the properties that difficult the NG storage is its low volumetric energy density, where an increase in its density is necessary to compete against the traditional fuels. In normal conditions of temperature and pressure (NTP), the yield (Y) of the NG in mobiles (mileage per unit fuel tank volume), directly related to their volumetric density, is about 0.12% respect to gasoline. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. The NG as fuel in mobile units presents a series of environmental benefits, compared to liquid fuels, as the reduction in the emission of contaminants and the minor costs in the maintenance of the vehicles. Compared to liquid fuels, the NGV presents up to 76% less of CO emissions; up to 75% less in NOx emissions; 88% less in hydrocarbons emissions and up to 30% less for CO2 emissions. The disadvantages of the NGV use are centered in the storage of the NG, due to its characteristics. One of the properties that difficult the NG storage is its low volumetric energy density, where an increase in its density is necessary to compete against the traditional fuels. In normal conditions of temperature and pressure (NTP), the yield (Y) of the NG in mobiles (mileage per unit fuel tank volume), directly related to their volumetric density, is about 0.12% respect to gasoline. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. The NG as fuel in mobile units presents a series of environmental benefits, compared to liquid fuels, as the reduction in the emission of contaminants and the minor costs in the maintenance of the vehicles. Compared to liquid fuels, the NGV presents up to 76% less of CO emissions; up to 75% less in NOx emissions; 88% less in hydrocarbons emissions and up to 30% less for CO2 emissions. The disadvantages of the NGV use are centered in the storage of the NG, due to its characteristics. One of the properties that difficult the NG storage is its low volumetric energy density, where an increase in its density is necessary to compete against the traditional fuels. In normal conditions of temperature and pressure (NTP), the yield (Y) of the NG in mobiles (mileage per unit fuel tank volume), directly related to their volumetric density, is about 0.12% respect to gasoline. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet. One second option is the use of the compressed natural gas (CNG), widely used nowadays, reaching a rapid growth in several countries with its correspondent success, but the storage pressure at room temperature is higher than 25 MPa, which complicates the process and increases the costs, requiring the use of resistant materials as well as the presence of compressors in the gas stations to increase the pressure. In this case, the density is about 250 times superior to the NG in NCPT, reaching a Y of 26% compared to the gasoline. A third alternative, which has an important development at scientific level, with promising results, is the use of the natural gas adsorption process with special materials that can reach similar results to CNG at room temperature but at much lower pressures (3-4 MPa). This process is denominated adsorbed natural gas (ANG) and, given that the primordial component of the natural gas is the methane (>95%), most of the research is carried out with this hydrocarbon, as the representative molecule of the NG. By the process of storage by adsorption and utilizing adsorbent materials with the proper characteristics (microporous solids), like zeolites and activated carbons (AC), there are important results with technological perspectives. Adsorbents have to fulfill certain conditions regarding their texture (specific surface and porosity) and surface chemistry to get optimal storage capacity related to the energetic density of the NG. An important parameter of technologic interest is related to the volume of storage methane per volume of utilized adsorbent, Q. Several countries have already set out their scientific objectives regarding to the development of adsorbents to achieve a Q value between 100 and 150, which impulse many researchers to work in the view to reach this goal. The study of this subject (ANG) is taken on, by one hand, from the experimental point of view, with the synthesis of materials, their characterization and the analysis of the adsorption of methane from low (sub atmospheric) to high pressures (about 4MPa). On the other hand, the computing simulation contributes to the comprehension and improvement of these processes where the use of the density functional theory (DFT) and the Monte Carlo method (MC) give important contributions not only about the optimal characteristics of the materials to study but also about the way in which the process is developed, providing data, for example, as the density of the gas phase is in the adsorbed state. In this chapter, it is presented a basic revision to understand the process of the methane adsorption, in particular on porous materials. Experimental and computational methods, used to study the application and characterization of the materials, are described, pointing out the information obtained from them. Finally, some examples about the utilization of the most relevant porous materials for the application of the ANG are given. Among the described materials, the results obtained with materials synthesized in our laboratory are stated, in particular activated carbons produced from a variety of agricultural wastes, like wood, peel and stones from different fruits. The obtained materials were evaluated in the adsorption of methane in a wide range of pressures, as a previous step for their utilization like potential adsorbents in the storage of natural gas. Their textural characteristics were obtained by adsorption of different gases at different temperatures and pressures, obtaining interesting information. Some studies of computing simulation by the Monte Carlo method, for the most relevant cases, complete this work. The presented results suggest that the production of AC, potentially useful for the storage of NG from wastes, is a very interesting proposal, both from the environmental and economic points of view, due to the fact that the former material is a waste from other industries. Some of these results have been published in two recent articles. Among the alternatives to increase its density into the storage containers is the liquefied natural gas (LNG), with a volumetric density about 600 times higher than the NG at NTP, reaching a Y of 72% compared to the liquid fuel. LNG has the inconvenience that the NG is liquefied at very low temperatures (112K), at atmospheric pressure, which should be kept into the container. This process is expensive and inconvenient for mobile fleet.