Natural gas, mostly composed of methane, is a very reliable source of energy. Aside from being cheap, it is also abundant and environmentally clean. This is said as its byproducts are gaseous and it burns without the production of carbon soot or sulfur dioxide. It also produces less carbon dioxide compared to coal and oil.
As a consumer and industrial good, it is stored in three ways: compression, liquefaction, and adsorption. And among the three, adsorbed natural gas, or ANG, is the most advantageous as it is cheaper, safer, and more efficient than compressed natural gas, or CNG, and liquefied natural gas, or LNG. However, in the past, developing an effective adsorbent was a challenge to scientists, which is why we resort to other sources of energy like coal and petroleum.
Researchers from the Korea Advanced Institute of Science & Technology came up with a polymer that has a high methane gas adsorption capacity and presented their study in an issue of Nature Energy last July. The research was a product of the combined effort of one team led by Professor Cafer T. Yavuz from the Graduate School of Energy, Environment, Water, and Sustainability and another team led by Professor Mert Atilhan from Texas A&M University. They have together synthesized 29 distinct polymers, which they tested for methane gas uptake at high pressures. Physically, the polymers differed in terms of porosity, synthetic structure complexity, and morphology.
Out of the 29 polymers that they synthesized, the one that they labeled COP-150 had a notably high capacity at a temperature of 273K and pressures between five and 100 bar. The high deliverable gravimetric methane working capacity at these conditions was 98% of the total capacity, a high pass when compared to the targeted value of the US Department of Energy.
During adsorption at increased pressure, the polymers were observed to expand and at lower pressure, the polymers contracted. This emphasized the flexible characteristic of the polymer, which means that it can adjust to surrounding conditions such as sudden changes in temperature. The expansion-contraction mechanism was also believed to minimize contamination since when no natural gas is stored, the material remains compact and contracted.
To top the remarkable presentation of the synthesized polymer, the material was also cheap to produce. The raw materials were readily accessible plastic materials and the synthesis was done at room temperature, without the need for pretreatment or purification of the chemicals before the synthesis.
With this development, the use of natural gas can be increased and that of coal and petroleum may be decreased. This will help reduce greenhouse gas emissions and help our environment.