The present work summarizes recent investigations carried out about the usage of natural antioxidants in lipid-rich food during processing. Synthetic antioxidants have been used as food additives to retard lipid oxida...The present work summarizes recent investigations carried out about the usage of natural antioxidants in lipid-rich food during processing. Synthetic antioxidants have been used as food additives to retard lipid oxidation and development of off-flavor for over 50 years. However, the literature has expressed safety concerns and health risks （toxic and carcinogenic effects） associated with the use of synthetic antioxidants recently. Natural antioxidative substances from the polyphenols of edible plants are believed to be safer and may provide with additional health benefits and more effective compared to synthetic antioxidants. Due to the fact that natural antioxidants are additives that people mixed with food and consumed for centuries, they are known to be safe by the consumer. Therefore, it is an area worth to investigate due to consumer concerns about health. In the literature, there are many studies showing that the natural antioxidants have important antioxidant effect. Plants （oil seeds, cereals, vegetables, fruits, herb and spices）, compounds from animal source （peptides and amino acids）, enzymes and some microorganisms are important natural antioxidants. Plant extracts have been widely used to retard lipid oxidation in foods during frying and accelerated storage processes. They were found as strong antioxidant sources due to their high contents of phenolic compounds. There are countless studies about natural antioxidants. However, they have not been investigated completely by means of toxicology.展开更多
On the basis of formulating the 9-lump kinetic model for gasoline catalytic upgrading and the 12- lump kinetic model for heavy oil FCC, this paper is aimed at development of a combined kinetic model for a typical FDFC...On the basis of formulating the 9-lump kinetic model for gasoline catalytic upgrading and the 12- lump kinetic model for heavy oil FCC, this paper is aimed at development of a combined kinetic model for a typical FDFCC process after analyzing the coupled relationship and combination of these two models. The model is also verified by using commercial data, the results of which showed that the model can better predict the product yields and their quality, with the relative errors between the main products of the unit and commercial data being less than five percent. Furthermore, the combined model is used to predict and optimize the operating conditions for gasoline riser and heavy oil riser in FDFCC. So this paper can offer some guidance for the processing of FDFCC and is instructive to model research and development of such multi-reactor process and combined process.展开更多
An efficient analytical method combining pyrolysis and capillary GC/MS has been developed for determination and quantitation of targeted polycyclic aromatic hydrocarbons.The limit of detection ranged from 0.29 μg/g t...An efficient analytical method combining pyrolysis and capillary GC/MS has been developed for determination and quantitation of targeted polycyclic aromatic hydrocarbons.The limit of detection ranged from 0.29 μg/g to 43.46 μg/g,and repeatability values were between 0.1% and 8.2% for blank spiked samples and between 0.1 % and 9.8% for real samples of heavy oils.Through application of the proposed method in hydrotreating processes,it has been found out that heavy oils before and after the specified hydroprocessing treatment exhibited a diverse PAHs distribution which might be determined by the discrepancy in their intrinsic contents and hydrogenation reactivity.Furthermore,the hydrogenation reactivity of different polycyclic aromatic hydrocarbons was further investigated and discovered to be more interrelated to molecular structure and rings alignment or conjugation mode.展开更多
According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydr...According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.展开更多
Computer simulation is a good guide and reference for development and research on petroleum refining processes. Traditionally, pseudo-components are used in the simulation, in which their physical properties are estim...Computer simulation is a good guide and reference for development and research on petroleum refining processes. Traditionally, pseudo-components are used in the simulation, in which their physical properties are estimated by empirical relations and cannot be associated with actual chemical reactions, as no molecular structure is available for pseudo-components. This limitation can be overcome if real components are used. In this paper, a real component based method is proposed for the simulation of a diesel hydrotreating process by using the software of Unisim Design. This process includes reaction units and distillation units. The chemical reaction network is established by analyzing the feedstock. The feedstock is characterized by real components, which are obtained based on true boiling point curve. Simulation results are consistent with actual data.展开更多
Thermal upgrading of vacuum residue mixed with waste plastics was studied in a laboratory scale delayed coking unit.The model of feed thermal decomposition was set up and the first order reaction kinetics was used to ...Thermal upgrading of vacuum residue mixed with waste plastics was studied in a laboratory scale delayed coking unit.The model of feed thermal decomposition was set up and the first order reaction kinetics was used to predict products distribution during the coking process.The distillate yield was higher(70%) for the vacuum residue/polystyrene(VR/PS) feed system and the vacuum residue/low density polyethylene(VR/LDPE) feed system.The resulted distillate yield was separated into fractions according to their boiling points,with gasoline and diesel being our fractions of concern.The activation energy was higher for gasoline production(around 60 kcal/mol) varying with the type of feed system,while it was 33 kcal/mol for diesel fraction.The regression coefficient R was 0.990.展开更多
文摘The present work summarizes recent investigations carried out about the usage of natural antioxidants in lipid-rich food during processing. Synthetic antioxidants have been used as food additives to retard lipid oxidation and development of off-flavor for over 50 years. However, the literature has expressed safety concerns and health risks （toxic and carcinogenic effects） associated with the use of synthetic antioxidants recently. Natural antioxidative substances from the polyphenols of edible plants are believed to be safer and may provide with additional health benefits and more effective compared to synthetic antioxidants. Due to the fact that natural antioxidants are additives that people mixed with food and consumed for centuries, they are known to be safe by the consumer. Therefore, it is an area worth to investigate due to consumer concerns about health. In the literature, there are many studies showing that the natural antioxidants have important antioxidant effect. Plants （oil seeds, cereals, vegetables, fruits, herb and spices）, compounds from animal source （peptides and amino acids）, enzymes and some microorganisms are important natural antioxidants. Plant extracts have been widely used to retard lipid oxidation in foods during frying and accelerated storage processes. They were found as strong antioxidant sources due to their high contents of phenolic compounds. There are countless studies about natural antioxidants. However, they have not been investigated completely by means of toxicology.
文摘On the basis of formulating the 9-lump kinetic model for gasoline catalytic upgrading and the 12- lump kinetic model for heavy oil FCC, this paper is aimed at development of a combined kinetic model for a typical FDFCC process after analyzing the coupled relationship and combination of these two models. The model is also verified by using commercial data, the results of which showed that the model can better predict the product yields and their quality, with the relative errors between the main products of the unit and commercial data being less than five percent. Furthermore, the combined model is used to predict and optimize the operating conditions for gasoline riser and heavy oil riser in FDFCC. So this paper can offer some guidance for the processing of FDFCC and is instructive to model research and development of such multi-reactor process and combined process.
基金support from the National Key Basic Research Science Foundation (Grant No. 2006CB202500. 4-1)
文摘An efficient analytical method combining pyrolysis and capillary GC/MS has been developed for determination and quantitation of targeted polycyclic aromatic hydrocarbons.The limit of detection ranged from 0.29 μg/g to 43.46 μg/g,and repeatability values were between 0.1% and 8.2% for blank spiked samples and between 0.1 % and 9.8% for real samples of heavy oils.Through application of the proposed method in hydrotreating processes,it has been found out that heavy oils before and after the specified hydroprocessing treatment exhibited a diverse PAHs distribution which might be determined by the discrepancy in their intrinsic contents and hydrogenation reactivity.Furthermore,the hydrogenation reactivity of different polycyclic aromatic hydrocarbons was further investigated and discovered to be more interrelated to molecular structure and rings alignment or conjugation mode.
基金the financial support from the SINOPEC(No.2014310031600599)
文摘According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.
文摘Computer simulation is a good guide and reference for development and research on petroleum refining processes. Traditionally, pseudo-components are used in the simulation, in which their physical properties are estimated by empirical relations and cannot be associated with actual chemical reactions, as no molecular structure is available for pseudo-components. This limitation can be overcome if real components are used. In this paper, a real component based method is proposed for the simulation of a diesel hydrotreating process by using the software of Unisim Design. This process includes reaction units and distillation units. The chemical reaction network is established by analyzing the feedstock. The feedstock is characterized by real components, which are obtained based on true boiling point curve. Simulation results are consistent with actual data.
文摘Thermal upgrading of vacuum residue mixed with waste plastics was studied in a laboratory scale delayed coking unit.The model of feed thermal decomposition was set up and the first order reaction kinetics was used to predict products distribution during the coking process.The distillate yield was higher(70%) for the vacuum residue/polystyrene(VR/PS) feed system and the vacuum residue/low density polyethylene(VR/LDPE) feed system.The resulted distillate yield was separated into fractions according to their boiling points,with gasoline and diesel being our fractions of concern.The activation energy was higher for gasoline production(around 60 kcal/mol) varying with the type of feed system,while it was 33 kcal/mol for diesel fraction.The regression coefficient R was 0.990.
