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
The eutectic ionic liquid(EIL) tetraethyl ammonium bromide-malonic acid(TEAB-Mal) was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1 H NMR spectrometry. The performance for removal o...The eutectic ionic liquid(EIL) tetraethyl ammonium bromide-malonic acid(TEAB-Mal) was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1 H NMR spectrometry. The performance for removal of basic nitrogen compounds by EIL was studied using coker diesel as the feedstock. Experimental results showed that the EIL(TEAB-Mal) exhibited a good denitrogenation performance, leading to a 93.6% of basic N-removal efficiency under reaction conditions covering: a temperature of 30 °C, an EIL to oil mass ratio of 1:1, an extraction time of 30 min, and a settling time of 120 min, while the basic nitrogen content in diesel dropped from 580 μg/g to 37 μg/g. In addition, the efficiency for extraction of basic N-compounds could still reach 62.9% at an EIL/oil mass ratio of 1:7 after four recycles of the EIL.展开更多
The undigested nitrogenous fraction entering the hindgut of chickens is further metabolized by microbiota present producing volatile basic metabolites including amines and ammonia(NH3).Ammonia increases pH and may res...The undigested nitrogenous fraction entering the hindgut of chickens is further metabolized by microbiota present producing volatile basic metabolites including amines and ammonia(NH3).Ammonia increases pH and may result in overgrowth of Clostridium perfringens further producing toxic metabolites that cause dysbacteriosis or necrotic enteritis(NE).There are few reports in chickens examining the production and concentration of nitrogenous metabolites in the hindgut.A Berthelot reaction using an automated flow,reaction and spectrophotometric instrumentation to detect volatile basic nitrogen in the form of NH3 from cecal contents was carried out.In the Berthelot reaction,NH3 in the sample is chlorinated to monochloramine using dichloroisocyanuric acid that then reacts with salicylate to form 5-aminosalicylate which is stable under alkaline conditions(pH 12 to 13).After oxidation and oxidative coupling,a coloured complex is formed that can be measured at 660 nm.Cecal contents were collected and pooled from 2 birds per pen with 48 pens total in each of 3 experiments and stored in sealed containers at-20℃prior to analysis.Experiment 1 compared samples collected from birds fed either no meat and bone meal(MBM)or 6%MBM from d 0 to 14,and samples collected from birds fed either no MBM or 5%MBM from d 14 to 42.All birds were challenged with Eimeria on d 9 and C.perfringens on d 14 and 15.Experiment 2 compared cecal contents from birds fed either 0.5%or 0.9%calcium(Ca),and Exp.3 compared unchallenged with NE challe nge on d 16 and 29.Results demonstrated an increase(P<0.05)in cecal NH3 as a result of feeding MBM or high dietary Ca with a corresponding increase in pH.Birds experimentally challenged with NE had lower cecal NH3 and lower pH on d 16 but not d 29 compa red to unchallenged controls.It was concluded that the Berthelot method using Skalar instrumentation equipment is suitable to measure the concentration of volatile nitrogen as NH3 in cecal contents of chickens.展开更多
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
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
为进一步控制鳜鱼片的品质及质量安全,研究不同贮藏温度下鳜鱼片的品质变化规律。将鳜鱼片分别置于4、7、10℃,测定总挥发性盐基氮(volatile base nitrogen,TVB-N)含量、pH值、持水力、菌落总数和色度值,确定4、7、10℃贮藏温度下鳜鱼...为进一步控制鳜鱼片的品质及质量安全,研究不同贮藏温度下鳜鱼片的品质变化规律。将鳜鱼片分别置于4、7、10℃,测定总挥发性盐基氮(volatile base nitrogen,TVB-N)含量、pH值、持水力、菌落总数和色度值,确定4、7、10℃贮藏温度下鳜鱼片的货架期。结果表明:随着贮藏时间的延长,各实验组的菌落总数、pH值和TVB-N含量均呈上升趋势(P<0.05),持水力显著下降(P<0.05);TVB-N含量的初始值较低,为6.39 mg/100 g,在9 d的贮藏期后,4、7、10℃贮藏温度下鳜鱼片分别增长5、8、9倍。结合各指标综合来看,4、7、10℃贮藏温度下鳜鱼片的货架期分别为3、2、1 d。展开更多
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the financial support from the Doctoral Funds of Liaoning Provincial Natural Science Foundation(201601323)
文摘The eutectic ionic liquid(EIL) tetraethyl ammonium bromide-malonic acid(TEAB-Mal) was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1 H NMR spectrometry. The performance for removal of basic nitrogen compounds by EIL was studied using coker diesel as the feedstock. Experimental results showed that the EIL(TEAB-Mal) exhibited a good denitrogenation performance, leading to a 93.6% of basic N-removal efficiency under reaction conditions covering: a temperature of 30 °C, an EIL to oil mass ratio of 1:1, an extraction time of 30 min, and a settling time of 120 min, while the basic nitrogen content in diesel dropped from 580 μg/g to 37 μg/g. In addition, the efficiency for extraction of basic N-compounds could still reach 62.9% at an EIL/oil mass ratio of 1:7 after four recycles of the EIL.
文摘The undigested nitrogenous fraction entering the hindgut of chickens is further metabolized by microbiota present producing volatile basic metabolites including amines and ammonia(NH3).Ammonia increases pH and may result in overgrowth of Clostridium perfringens further producing toxic metabolites that cause dysbacteriosis or necrotic enteritis(NE).There are few reports in chickens examining the production and concentration of nitrogenous metabolites in the hindgut.A Berthelot reaction using an automated flow,reaction and spectrophotometric instrumentation to detect volatile basic nitrogen in the form of NH3 from cecal contents was carried out.In the Berthelot reaction,NH3 in the sample is chlorinated to monochloramine using dichloroisocyanuric acid that then reacts with salicylate to form 5-aminosalicylate which is stable under alkaline conditions(pH 12 to 13).After oxidation and oxidative coupling,a coloured complex is formed that can be measured at 660 nm.Cecal contents were collected and pooled from 2 birds per pen with 48 pens total in each of 3 experiments and stored in sealed containers at-20℃prior to analysis.Experiment 1 compared samples collected from birds fed either no meat and bone meal(MBM)or 6%MBM from d 0 to 14,and samples collected from birds fed either no MBM or 5%MBM from d 14 to 42.All birds were challenged with Eimeria on d 9 and C.perfringens on d 14 and 15.Experiment 2 compared cecal contents from birds fed either 0.5%or 0.9%calcium(Ca),and Exp.3 compared unchallenged with NE challe nge on d 16 and 29.Results demonstrated an increase(P<0.05)in cecal NH3 as a result of feeding MBM or high dietary Ca with a corresponding increase in pH.Birds experimentally challenged with NE had lower cecal NH3 and lower pH on d 16 but not d 29 compa red to unchallenged controls.It was concluded that the Berthelot method using Skalar instrumentation equipment is suitable to measure the concentration of volatile nitrogen as NH3 in cecal contents of chickens.
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 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.
