Preparation of natural gas adsorbents under low activation ratio:
Enhancing storage capacity by using promoters

The natural gas adsorbents were prepared with KOH as activation agent and petroleum coke as feed under low activation ratio m_KOH/m_C of 2. The influences of promoters like KNO₃, NaNO₃, Mg(NO₃)₂, Ni(NO₃)₂ and HJ on the methane storage performance of the adsorbents were investigated. The mechanism for the enhancement in the adsorbent capacity by using promoter was analyzed in detail. The results show that the adsorbents with good storage performance can be obtained by adding suitable amounts of KNO₃, Mg(NO₃)₂, Ni(NO₃)₂ or HJ into mixed activation materials. Furthermore, Mg (NO₃)₂, Ni (NO₃)₂ coupling with HJ gives excellent co-activation effect on the adsorbents prepared. The methane mass uptake and discharging volume of the adsorbent Mg3HJ2, prepared with 10% (mass ratio of the promoter to coke) of Mg (NO₃)₂ and HJ, reaches 0.143 and 117.1, respectively, under 25℃ and 3.5MPa. The storage capacity of Mg3HJ2 is even higher than that of the adsorbent FS3 obtained under the activation ratio of 3 without using any promoter.