This review discussed the use of nano ZSM‐5 in naphtha catalytic cracking.The impact of nano ZSM‐5 on product selectivity,reaction conversion and catalyst lifetime were compared with micro‐sized ZSM‐5.The applicat...This review discussed the use of nano ZSM‐5 in naphtha catalytic cracking.The impact of nano ZSM‐5 on product selectivity,reaction conversion and catalyst lifetime were compared with micro‐sized ZSM‐5.The application of nano ZSM‐5 not only increased the catalyst lifetime,but also gave more stability for light olefins selectivity.The effects of the reaction parameters of temperature and feedstock on the performance of nano ZSM‐5 were investigated,and showed that high temperature and linear alkanes as feedstock improved light olefin selectivity and conversion.展开更多
In the steam thermal cracking of naphtha,the hydrocarbon stream flows inside tubular reactors and is exposed to flames of a series of burners in the firebox.In this paper,a full three-dimensional computational fluid d...In the steam thermal cracking of naphtha,the hydrocarbon stream flows inside tubular reactors and is exposed to flames of a series of burners in the firebox.In this paper,a full three-dimensional computational fluid dynamics(CFD)model was developed to investigate the process variables in the firebox and reactor coil of an industrial naphtha furnace.This comprehensive CFD model consists of a standard k-εturbulence model accompanied by a molecular kinetic reaction for cracking,detailed combustion model,and radiative properties.In order to improve the steam cracking performance,the model is solved using a proposed iterative algorithm.With respect to temperature,product yield and specially propylene-toethylene ratio(P/E),the simulation results agreed well with industrial data obtained from a mega olefin plant of a petrochemical complex.The deviation of P/E results from industrial data was less than 2%.The obtained velocity,temperature,and concentration profiles were used to investigate the residence time,coking rate,coke concentration,and some other findings.The coke concentration at coil exit was1.9×10^(-3)%(mass)and the residence time is calculated to be 0.29 s.The results can be used as a scientific guide for process engineers.展开更多
Ethylene production by the thermal cracking of naphtha is an energy-intensive process （up to 40 GJ heat per tonne ethylene）, leading to significant formation of coke and nitrogen oxide （NOx）, along with 1,8- 2 kg ...Ethylene production by the thermal cracking of naphtha is an energy-intensive process （up to 40 GJ heat per tonne ethylene）, leading to significant formation of coke and nitrogen oxide （NOx）, along with 1,8- 2 kg of carbon dioxide （CO2） emission per kilogram of ethylene produced, We propose an alternative pro- cess for the redox oxy-cracking （ROC） of naphtha, In this two-step process, hydrogen （H2） from naphtha cracking is selectively comhusted by a redox catalyst with its lattice oxygen first, The redox catalyst is subsequently re-oxidized by air and releases heat, which is used to satisfy the heat requirement for the cracking reactions, This intensified process reduces parasitic energy consumption and CO2 and NOx emissions, Moreover, the formation of ethylene and propylene can he enhanced due to the selective com-bustion of H2, In this study, the ROC process is simulated with ASPEN Plus^R based on experimental data from recently developed redox catalysts, Compared with traditional naphtha cracking, the ROC process can provide up to 52% reduction in energy consumption and CO2 emissions, The upstream section of the process consumes approximately 67% less energy while producing 28% more ethylene and propylene for every kilogram of naphtha feedstock,展开更多
As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naph...As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.展开更多
The 3rd generation catalytic cracking naphtha selective hydrodesulfurization(RSDS-III) technology developed by RIPP included the catalysts selective adjusting(RSAT) technology, the development of new catalysts and opt...The 3rd generation catalytic cracking naphtha selective hydrodesulfurization(RSDS-III) technology developed by RIPP included the catalysts selective adjusting(RSAT) technology, the development of new catalysts and optimized process conditions. The pilot plant test results showed that the RSDS-III technology could be adapted to different feedstocks. The sulfur content dropped from 600 μg/g and 631 μg/g to 7 μg/g and 9 μg/g, respectively, by RSDS-III technology when feed A and feed B were processed to meet China national V gasoline standard, with the RON loss of products equating to 0.9 units and 1.0 unit, respectively. While the feed C with a medium sulfur content was processed according to the full-range naphtha hydrotreating technology, the sulfur content dropped from 357 μg/g in the feed to 10 μg/g in gasoline, with the RON loss of product decreased by only 0.6 units. Thanks to the high HDS activity and good selectivity of RSDS-III technology, the ultra-low-sulfur gasoline meeting China V standard could be produced by the RSDS-III technology with little RON loss.展开更多
文摘This review discussed the use of nano ZSM‐5 in naphtha catalytic cracking.The impact of nano ZSM‐5 on product selectivity,reaction conversion and catalyst lifetime were compared with micro‐sized ZSM‐5.The application of nano ZSM‐5 not only increased the catalyst lifetime,but also gave more stability for light olefins selectivity.The effects of the reaction parameters of temperature and feedstock on the performance of nano ZSM‐5 were investigated,and showed that high temperature and linear alkanes as feedstock improved light olefin selectivity and conversion.
基金the support of Bandar-eImam petrochemical company(BIPC),Iran。
文摘In the steam thermal cracking of naphtha,the hydrocarbon stream flows inside tubular reactors and is exposed to flames of a series of burners in the firebox.In this paper,a full three-dimensional computational fluid dynamics(CFD)model was developed to investigate the process variables in the firebox and reactor coil of an industrial naphtha furnace.This comprehensive CFD model consists of a standard k-εturbulence model accompanied by a molecular kinetic reaction for cracking,detailed combustion model,and radiative properties.In order to improve the steam cracking performance,the model is solved using a proposed iterative algorithm.With respect to temperature,product yield and specially propylene-toethylene ratio(P/E),the simulation results agreed well with industrial data obtained from a mega olefin plant of a petrochemical complex.The deviation of P/E results from industrial data was less than 2%.The obtained velocity,temperature,and concentration profiles were used to investigate the residence time,coking rate,coke concentration,and some other findings.The coke concentration at coil exit was1.9×10^(-3)%(mass)and the residence time is calculated to be 0.29 s.The results can be used as a scientific guide for process engineers.
基金This work was supported by the US National Science Foundation （CBET-1604605） and the Kenan Institute for Engineering, Technol-ogy and Science at North Carolina State University.
文摘Ethylene production by the thermal cracking of naphtha is an energy-intensive process （up to 40 GJ heat per tonne ethylene）, leading to significant formation of coke and nitrogen oxide （NOx）, along with 1,8- 2 kg of carbon dioxide （CO2） emission per kilogram of ethylene produced, We propose an alternative pro- cess for the redox oxy-cracking （ROC） of naphtha, In this two-step process, hydrogen （H2） from naphtha cracking is selectively comhusted by a redox catalyst with its lattice oxygen first, The redox catalyst is subsequently re-oxidized by air and releases heat, which is used to satisfy the heat requirement for the cracking reactions, This intensified process reduces parasitic energy consumption and CO2 and NOx emissions, Moreover, the formation of ethylene and propylene can he enhanced due to the selective com-bustion of H2, In this study, the ROC process is simulated with ASPEN Plus^R based on experimental data from recently developed redox catalysts, Compared with traditional naphtha cracking, the ROC process can provide up to 52% reduction in energy consumption and CO2 emissions, The upstream section of the process consumes approximately 67% less energy while producing 28% more ethylene and propylene for every kilogram of naphtha feedstock,
基金support of the National Natural Science Foundation of China(Nos.22378369 and 22205207)Major Project of Natural Science Foundation of Zhejiang Province(LD24B060001).
文摘As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.
基金the financial support from the SINOPEC(No.114016)
文摘The 3rd generation catalytic cracking naphtha selective hydrodesulfurization(RSDS-III) technology developed by RIPP included the catalysts selective adjusting(RSAT) technology, the development of new catalysts and optimized process conditions. The pilot plant test results showed that the RSDS-III technology could be adapted to different feedstocks. The sulfur content dropped from 600 μg/g and 631 μg/g to 7 μg/g and 9 μg/g, respectively, by RSDS-III technology when feed A and feed B were processed to meet China national V gasoline standard, with the RON loss of products equating to 0.9 units and 1.0 unit, respectively. While the feed C with a medium sulfur content was processed according to the full-range naphtha hydrotreating technology, the sulfur content dropped from 357 μg/g in the feed to 10 μg/g in gasoline, with the RON loss of product decreased by only 0.6 units. Thanks to the high HDS activity and good selectivity of RSDS-III technology, the ultra-low-sulfur gasoline meeting China V standard could be produced by the RSDS-III technology with little RON loss.
