The ongoing energy and environmental crises have pushed the transportation sector, a major greenhouse gas emitter, to seek sustainable fuel and technology alternatives. Natural gas and bio-methane are potential alternatives with numerous advantages over conventional fuels. Adsorbed natural gas (ANG) technology uses porous adsorbent material to store methane efficiently at lower pressures. An issue limiting this technology is the lack of compact tanks with efficient adsorbent packing that increase storage capacity. This study addresses the need for more compact ANG tanks by creating novel binder-less monolithic activated carbon monolith adsorbents with targeted porosity. A template is produced using 3D printing and a commercially available phenolic resin as a filling material. Upon thermal treatment, the 3D-printed template combusts with molecular oxygen in its structure, and the resin is transformed into activated carbon by pyrolysis. Longer activation times led to higher BET surface areas. However, after activation periods beyond 15 minutes, the surface area increase is obtained at the expense of a higher burn-off, which affects the material density. Adsorption of 0.04g/g of methane was measured at 30 bar and 298 K on the activated carbon monolith with the highest BET surface area (516 m2/g). Results in the same conditions on a super high surface area Maxsorb activated carbon were 0.13g/g. Although the methane capacity obtained is lower than in a commercial sample, it was demonstrated that producing an activated carbon monolith with tailored porosity is possible. New techniques for activation should be studied to enhance their gravimetric capacity to make ANG competitive.

Made available in DSpace on 2015-05-08T15:00:00Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1517568 bytes, checksum: a6cac1f3e9aad558237c5fdc4a2cf439 (MD5) Previous issue date: 2009-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aims to experimentally examine the dynamics of sorption during the loading process of natural gas in an adsorptive column, filled with activated charcoal, for storage of natural gas. The column represents an element of a tank car adsorptive multitubular that allows the movement of gas through a heat exchanger external to the dissipation of heat generated in the adsorption bed during the exothermal porous load of gas. A bench trial was mounted and instrumented for the acquisition of thermograms in the column, the pressure drop and mass flow of gas. The experimental results were compared with results of numerical simulation. Depending on the flow rate applied, the time of loading of the system can vary between 50 and 250 seconds. These times are considered satisfactory for rapid loading conditions. Finally, the results show that the velocity of the gas can vary significantly, depending on the pressure and flow applied. / Este trabalho tem como objetivo analisar experimentalmente a dinâmica de sorção durante processo de carga de gás natural em uma coluna adsortiva, preenchida com carvão ativado, para armazenamento de gás natural. A coluna representa um elemento de um tanque automotivo adsortivo multitubular que permite a circulação do gás através de um trocador de calor externo necessário para a dissipação do calor de adsorção gerado no leito poroso durante o processo exotérmico de carga de gás. Uma bancada experimental foi montada e instrumentada para permitir a obtenção de termogramas no interior da coluna, queda de pressão e vazão mássica do gás. Os resultados experimentais foram comparados com resultados de simulação numérica. Dependendo da vazão aplicada, o tempo de carga desse sistema pode variar entre 50 e 250 segundos. Esses tempos são considerados satisfatórios para condições de carga rápida. Finalmente, os resultados mostram que a velocidade do gás pode variar significativamente, dependendo da pressão e da vazão aplicada.