Adsorption Of Nitrogen Containing Compounds From Oil By Carbon-based Materials

With the intensification of global environmental issues, countries around the world have develop more stringent regulations to limit the nitrogen content of the fuel. To produce ultra-clean fuels with ultra- low containing of sulfur and nitrogen is the major issues for the refining industry. However, the traditional hydrodenitrogenation technology(HDN) has many challenges, such as, high temperature, high pressure and significant hydrogen consumption. The researchers has explored more effective and more friendly methods, such as extraction of nitrogen, biological denitrification, adsorption denitrogenation(ADN) and so on. Among them, ADN are attracting more and more attention in recent years due to many benefits, such as simple production technology, low cost, low operating risk and environmental friendly.A large number of scientific research shows that: activated carbon(AC) and its modified products have better adsorption capacity than other adsorbents for nitrogen compounds, and possible to achieve selective adsorption. Thus, carbon-based materials are recognized as the most effective materials for potential applications in ADN. This paper chose two carbon-based material which has huge difference in pore properties, and modified by oxidation to introduction a large number of oxygen-containing functional groups(OCFGs), then used to the adsorption denitrification of the model fuel and the real oil.The results show that oxidation can introduce great numbers of oxygen-containing functional groups to the surface of activated carbon and graphite, the adsorption capacity for quinoline for oxidative activated carbon(OAC) and graphite oxide(GO) was estimate about 33 mg-N/g and 25 mg-N/g; OCFGs are benefit for the adsorption of sulfur and nitrogen compounds; the effect of substituent groups on quinoline and the solvents were also investigated in this study; the adsorption mechanism were related to the numbers of OCFGs and the acid-base property of the adsorbate, for the low concentration of OCFGs adsorbents, π-π adsorption and physical adsorption play a dominant role while at the high OCFGs contents was the hydrogen bonding and acid-base interaction. The adsorption results of real fuel show that after appropriate oxidative modification the adsorption capacity of nitrogen compounds on activated carbon and graphite could be largely improved, and they could be used as the commercial ADN adsorbents.