Delayed coking is an important process in refinery to convert heavy residue oils from crude distillation units （CDUs） and fluid catalytic cracking units （FCCUs） into dry gas, liquefied petroleum gas （LPG）, gasol...Delayed coking is an important process in refinery to convert heavy residue oils from crude distillation units （CDUs） and fluid catalytic cracking units （FCCUs） into dry gas, liquefied petroleum gas （LPG）, gasoline, die- sel, gas oils and cokes. The main fractionator, separating superheating reaction vapors from the coke drums into lighter oil products, involves a de-superheating section and a rectifying section, and couldn＇t be simulated as a whole column directly because of non-eouilibrium in the de-suoerheatine section. It is verv imoortant to correctlv simulate the main fractionator for operational parameter and energy-use optimization of delayed cokers. This paper discusses the principle of de-superheating processes, and then proposes a new simulation strategy. Some key issues such as composition prediction of the reaction vapors, selection of thermodynamic methods, estimation of tray efficiency, etc. are discussed. The proposed simulation approach is applied to two industrial delayed cokers with typical technological processes in a Chinese refinery by using PRO/II. The simulation results obtained are well consistent with the actual operation data, which indicates that the presented approach is suitable to simulate the main fraction- ators of delayed cokers or other distillation columns consisting of de-superheating sections and rectifying sections.展开更多
Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The...Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The test results obtained have shown that the property of super viscous oil has played a key role in the formation of shot cokes. After adjusting and optimizing the process indices the operating regime of the delayed coking unit at a throughput of 118t/h of the super viscous oil is specified as follows： a reaction temperature of 498-502℃, a reaction pressure of 0.17-0.25 MPa, a recycle ratio of 0.5-0.6 and a fractionation tower bottom temperature of 355-365 ℃. In the meantime, the delayed coking process has adopted measures to enhance pre-fractionation of the feedstock to rationally remove light fractions and maintain a steady gas velocity in order to avoid the formation of shot cokes.展开更多
The thermal upgrading of two residual oils tory-scale continuous delayed coking unit. The goal with different characteristics was studied in a labora- was to investigate the influence of the process vari- ables such a...The thermal upgrading of two residual oils tory-scale continuous delayed coking unit. The goal with different characteristics was studied in a labora- was to investigate the influence of the process vari- ables such as temperature, reaction time and additive on liquid yield and products distribution. A maximum liquid yield of 73% was achieved compared to 69% with the commercial unit. This yield was even increased to 75% under the effect of an additive. The fractionation of liquid oil by simulated vacuum distillation showed a high yield of diesel （46.9%）, compared to 28% for the commercial unit.展开更多
The current technology for producing the petroleum needle coke is apt to cause overflow of feedstock from the coke drums, instability in operation of coking unit, low mechanical strength of petroleum coke, and high pe...The current technology for producing the petroleum needle coke is apt to cause overflow of feedstock from the coke drums, instability in operation of coking unit, low mechanical strength of petroleum coke, and high percentage of coke powder, leading to difficulties in improving the overall quality of needle coke. Therefore, we have developed a new technology for producing the needle coke,featuring the manipulation of temperature range in a narrow scale at high pressure coupled with feedstock alternations. This new kind of technology has been successfully applied in a 60kt/a commercial coking unit. Provided that demand for the feedstock quality is satisfied, petroleum needle coke meeting the international quality standard can be manufactured using RIPP's technology for producing petroleum needle coke.展开更多
This article introduces the recent advances of China in the fields of process technology of delayed coking, enlarged equipment size, hydraulic decoking, automatic control and environmental protection. By the end of 20...This article introduces the recent advances of China in the fields of process technology of delayed coking, enlarged equipment size, hydraulic decoking, automatic control and environmental protection. By the end of 2004 the total capacity of delayed coking uniis in China had reached 37.24 Mt/a with the maximum coke drum diameter equating to 9.4 m. This article also presents the investmerit in delayed cokers and the current production status while pointing out the existing problems and future development trends.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
Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking...Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking liquids were characterized by electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS)and gas chromatographic techniques.High relatively abundant heteroatom compounds in the coking liquids were 1-4 aromatic-ring pyridinic nitrogen compounds,carbazoles,benzocarbazoles,phenols,mercaptans,benzothiophenes,dibenzothiophenes,and naphthobenzothiophenes.Coking liquids derived from various feeds had similar compound class types,molecular weight distribution ranges,and double bond equivalents(DBE).However,the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied.A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process.The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.展开更多
基金Supported by the National-Natural Science Foundation of China （21076233）, the Major Science and Technology R＆D Pro- gram of Guangdong Province （2010A080801003）.
文摘Delayed coking is an important process in refinery to convert heavy residue oils from crude distillation units （CDUs） and fluid catalytic cracking units （FCCUs） into dry gas, liquefied petroleum gas （LPG）, gasoline, die- sel, gas oils and cokes. The main fractionator, separating superheating reaction vapors from the coke drums into lighter oil products, involves a de-superheating section and a rectifying section, and couldn＇t be simulated as a whole column directly because of non-eouilibrium in the de-suoerheatine section. It is verv imoortant to correctlv simulate the main fractionator for operational parameter and energy-use optimization of delayed cokers. This paper discusses the principle of de-superheating processes, and then proposes a new simulation strategy. Some key issues such as composition prediction of the reaction vapors, selection of thermodynamic methods, estimation of tray efficiency, etc. are discussed. The proposed simulation approach is applied to two industrial delayed cokers with typical technological processes in a Chinese refinery by using PRO/II. The simulation results obtained are well consistent with the actual operation data, which indicates that the presented approach is suitable to simulate the main fraction- ators of delayed cokers or other distillation columns consisting of de-superheating sections and rectifying sections.
文摘Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The test results obtained have shown that the property of super viscous oil has played a key role in the formation of shot cokes. After adjusting and optimizing the process indices the operating regime of the delayed coking unit at a throughput of 118t/h of the super viscous oil is specified as follows： a reaction temperature of 498-502℃, a reaction pressure of 0.17-0.25 MPa, a recycle ratio of 0.5-0.6 and a fractionation tower bottom temperature of 355-365 ℃. In the meantime, the delayed coking process has adopted measures to enhance pre-fractionation of the feedstock to rationally remove light fractions and maintain a steady gas velocity in order to avoid the formation of shot cokes.
文摘The thermal upgrading of two residual oils tory-scale continuous delayed coking unit. The goal with different characteristics was studied in a labora- was to investigate the influence of the process vari- ables such as temperature, reaction time and additive on liquid yield and products distribution. A maximum liquid yield of 73% was achieved compared to 69% with the commercial unit. This yield was even increased to 75% under the effect of an additive. The fractionation of liquid oil by simulated vacuum distillation showed a high yield of diesel （46.9%）, compared to 28% for the commercial unit.
文摘The current technology for producing the petroleum needle coke is apt to cause overflow of feedstock from the coke drums, instability in operation of coking unit, low mechanical strength of petroleum coke, and high percentage of coke powder, leading to difficulties in improving the overall quality of needle coke. Therefore, we have developed a new technology for producing the needle coke,featuring the manipulation of temperature range in a narrow scale at high pressure coupled with feedstock alternations. This new kind of technology has been successfully applied in a 60kt/a commercial coking unit. Provided that demand for the feedstock quality is satisfied, petroleum needle coke meeting the international quality standard can be manufactured using RIPP's technology for producing petroleum needle coke.
文摘This article introduces the recent advances of China in the fields of process technology of delayed coking, enlarged equipment size, hydraulic decoking, automatic control and environmental protection. By the end of 2004 the total capacity of delayed coking uniis in China had reached 37.24 Mt/a with the maximum coke drum diameter equating to 9.4 m. This article also presents the investmerit in delayed cokers and the current production status while pointing out the existing problems and future development trends.
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.
基金supported by the National Natural Science Foundation of China(U1162204,21236009,21376262)
文摘Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking liquids were characterized by electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS)and gas chromatographic techniques.High relatively abundant heteroatom compounds in the coking liquids were 1-4 aromatic-ring pyridinic nitrogen compounds,carbazoles,benzocarbazoles,phenols,mercaptans,benzothiophenes,dibenzothiophenes,and naphthobenzothiophenes.Coking liquids derived from various feeds had similar compound class types,molecular weight distribution ranges,and double bond equivalents(DBE).However,the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied.A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process.The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.
