The DFT-based(density functional theory) ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum.The results have indicated that there is a distin...The DFT-based(density functional theory) ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum.The results have indicated that there is a distinct relationship between the protonation energy of nitrogen-containing compounds and their basicity.The more negative the protonation energy,the stronger the basicity is.It has been also found that aliphatic amines are more basic than pyridines or aromatic amines,and all these compounds are more basic than pyrroles.The addition of the aromatic rings can influence the basicity of anilines,while the 5- and 6-membered heterocyclic compounds function differently.The solvent properties may affect the basicity of these nitrogen-containing compounds.展开更多
The basic-nitrogen aromatic compounds in feedstocks and liquid products from the micro-reactor and soluble components of coke obtained during fluid catalytic cracking (FCC) process were analyzed by the micro-electrosp...The basic-nitrogen aromatic compounds in feedstocks and liquid products from the micro-reactor and soluble components of coke obtained during fluid catalytic cracking (FCC) process were analyzed by the micro-electrospray ionization (ESI) 9.4T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with an average mass resolving power of 300 000 at a mass range of 100-1 200. The analytical results revealed that the coker gas oil (CGO) contained a higher abundance of basic-nitrogen aromatic compounds with the type of -5N to -9N compared with those in deasphalted oil (DAO) and mixed FCC feedstock. After catalytic cracking, the abundance of lowly condensed basic-nitrogen aromatic compounds was much less than those of highly condensed aromatics in the liquid products, with the carbon number mainly ranging from 6 to 25 and the average carbon number of the side-chains equating to 1-5. On the contrary, with respect to the soluble components of coke, the abundance of lowly condensed basic-nitrogen aromatic compounds was more than those of highly condensed aromatics, and the carbon number ranged from 12 to 30, which was much smaller than that of the mixed FCC feedstock but slightly larger than that of the cracked liquid products. These results have provided some fundamental information on FCC process.展开更多
Nitrogen oxides(NO x)emission during the regeneration of coked fluid catalytic cracking(FCC)catalysts is an environmental issue.In order to identify the correlations between nitrogen species in coke and different nitr...Nitrogen oxides(NO x)emission during the regeneration of coked fluid catalytic cracking(FCC)catalysts is an environmental issue.In order to identify the correlations between nitrogen species in coke and different nitrogencontaining products in tail gas,three coked catalysts with multilayer structural coke molecules were prepared in a fixed bed with model compounds(o-xylene and quinoline)at first.A series of characterization methods were used to analyze coke,including elemental analysis,FT-IR,XPS,and TG–MS.XPS characterization indicates all coked catalysts present two types of nitrogen species and the type with a higher binding energy is related with the inner part nitrogen atoms interacting with acid sites.Due to the stronger adsorption ability on acid sites for basic nitrogen compounds,the multilayer structural coke has unbalanced distribution of carbon and nitrogen atoms between the inner part and the outer edge,which strongly affects gas product formation.At the early stage of regeneration,oxidation starts from the outer edge and the product NO can be reduced to N_2 in high CO concentration.At the later stage,the inner part rich in nitrogen begins to be exposed to O_2.At this period,the formation of CO decreases due to lack of carbon atoms,which is not bene ficial to the reduction of NO.Therefore,nitrogen species in the inner part of multilayer structural coke contributes more to NO X formation.Based on the multilayer structure model of coke molecule and its oxidation behavior,a possible strategy to control NO X emission was discussed merely from concept.展开更多
基金supported by the"973"project envisaged in the State Key Basic R&D Program(2006CB202505).
文摘The DFT-based(density functional theory) ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum.The results have indicated that there is a distinct relationship between the protonation energy of nitrogen-containing compounds and their basicity.The more negative the protonation energy,the stronger the basicity is.It has been also found that aliphatic amines are more basic than pyridines or aromatic amines,and all these compounds are more basic than pyrroles.The addition of the aromatic rings can influence the basicity of anilines,while the 5- and 6-membered heterocyclic compounds function differently.The solvent properties may affect the basicity of these nitrogen-containing compounds.
基金supported by the National Basic Research Program of China (2010CB226901)
文摘The basic-nitrogen aromatic compounds in feedstocks and liquid products from the micro-reactor and soluble components of coke obtained during fluid catalytic cracking (FCC) process were analyzed by the micro-electrospray ionization (ESI) 9.4T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with an average mass resolving power of 300 000 at a mass range of 100-1 200. The analytical results revealed that the coker gas oil (CGO) contained a higher abundance of basic-nitrogen aromatic compounds with the type of -5N to -9N compared with those in deasphalted oil (DAO) and mixed FCC feedstock. After catalytic cracking, the abundance of lowly condensed basic-nitrogen aromatic compounds was much less than those of highly condensed aromatics in the liquid products, with the carbon number mainly ranging from 6 to 25 and the average carbon number of the side-chains equating to 1-5. On the contrary, with respect to the soluble components of coke, the abundance of lowly condensed basic-nitrogen aromatic compounds was more than those of highly condensed aromatics, and the carbon number ranged from 12 to 30, which was much smaller than that of the mixed FCC feedstock but slightly larger than that of the cracked liquid products. These results have provided some fundamental information on FCC process.
基金Supported by the National Natural Science Foundation of China(21476263)the National Natural Science Foundation for Young Scholars(21206198)
文摘Nitrogen oxides(NO x)emission during the regeneration of coked fluid catalytic cracking(FCC)catalysts is an environmental issue.In order to identify the correlations between nitrogen species in coke and different nitrogencontaining products in tail gas,three coked catalysts with multilayer structural coke molecules were prepared in a fixed bed with model compounds(o-xylene and quinoline)at first.A series of characterization methods were used to analyze coke,including elemental analysis,FT-IR,XPS,and TG–MS.XPS characterization indicates all coked catalysts present two types of nitrogen species and the type with a higher binding energy is related with the inner part nitrogen atoms interacting with acid sites.Due to the stronger adsorption ability on acid sites for basic nitrogen compounds,the multilayer structural coke has unbalanced distribution of carbon and nitrogen atoms between the inner part and the outer edge,which strongly affects gas product formation.At the early stage of regeneration,oxidation starts from the outer edge and the product NO can be reduced to N_2 in high CO concentration.At the later stage,the inner part rich in nitrogen begins to be exposed to O_2.At this period,the formation of CO decreases due to lack of carbon atoms,which is not bene ficial to the reduction of NO.Therefore,nitrogen species in the inner part of multilayer structural coke contributes more to NO X formation.Based on the multilayer structure model of coke molecule and its oxidation behavior,a possible strategy to control NO X emission was discussed merely from concept.
