Modified ethylene-vinyl acetate copolymer(EVAM)and amino-functionalized nano-silica(NSiO_(2))par-ticles were employed as the base materials for the synthesis of the nanocomposite pour point depressant designated as EV...Modified ethylene-vinyl acetate copolymer(EVAM)and amino-functionalized nano-silica(NSiO_(2))par-ticles were employed as the base materials for the synthesis of the nanocomposite pour point depressant designated as EVAM-g-NSiO_(2).This synthesis involved a chemical grafting process within a solution system,followed by a structural characterization.Moreover,combining macro-rheological performance with microscopic structure observation,the influence of the nanocomposite pour point depressant on the rheological properties of the model waxy oil system was investigated.The results indicate that when the mass ratio of NSiO_(2) to EVAM is 1:100,the prepared EVAM-g-NSiO_(2) nanocomposite pour point depressant exhibits excellent pour point reduction and viscosity reduction properties.Moreover,the nanocomposite pour point depressant obtained through a chemical grafting reaction demonstrates structural stability(the bonding between the polymer and nanoparticles is stable).The pour points of model waxy oils doped with 500 mg/kg ethylene-vinyl acetate copolymer(EVA),EVAM,and EVAM/SiO_(2) were reduced from 34℃ to 23,20,and 21℃,respectively.After adding the same dosage of EVAM-g-NSiO_(2) nanocomposite pour point depressant,the pour point of the model wax oil decreased to 12℃ and the viscosity at 32℃ decreased from 2399 to 2396.9 mPa·s,achieving an impressive viscosity reduction rate of 99.9%.Its performance surpassed that of EVA,EVAM,and EVAM/SiO_(2).The EVAM-g-NSiO_(2) dispersed in the oil phase acts as the crystallization nucleus for wax crystals,resulting in a dense structure of wax crystals.The compact wax crystal blocks are difficult to overlap with each other,pre-venting the formation of a three-dimensional network structure,thereby improving the low-temperature flowability of the model waxy oil.展开更多
Pour point depressants （PPD） are used to improve the theology of waxy crude. The affect of various factors on the theological properties, and the thermal characteristics of waxy crude treated by PPD have been invest...Pour point depressants （PPD） are used to improve the theology of waxy crude. The affect of various factors on the theological properties, and the thermal characteristics of waxy crude treated by PPD have been investigated. The conclusions are as follows： PPD can reduce the pour point and abnormal point of waxy crude, broaden the temperature range of Newtonian fluid of waxy crude, and lower greatly the viscosity of non-Newtonian fluid of waxy crude. The influence of reheating and high-rate shear on the effect of PPD mainly depends on their temperature. When the reheating temperature is more than the abnormal point of crude by 10℃, the reheating process has little effect on the modification effect of PPD. However, when the reheating temperature is below the abnormal point of crude, the reheating process will reduce the modification effect of PPD. When temperature is above the abnormal point of crude, the high-rate shear has little effect on the modification effect of PPD. At a temperature range where a lot of wax is precipitating, high-rate shear will greatly reduce the modification effect of PPD.展开更多
The nanocomposite EVAL-CNT was produced by chemical grafting in the solution system through the esterification of ethylene-vinyl alcohol copolymer (EVAL) and carboxylated multi-walled carbon nanotubes (O-MWCNT), and i...The nanocomposite EVAL-CNT was produced by chemical grafting in the solution system through the esterification of ethylene-vinyl alcohol copolymer (EVAL) and carboxylated multi-walled carbon nanotubes (O-MWCNT), and its structural properties were characterized. The improvement of the rheological properties of the waxy oil system by the novel pour point depressant was investigated using macroscopic rheological measurements and microscopic observations. The results showed that EVAL-CNT nanocomposite pour point depressant (PPD) could significantly reduce the pour point and improve the low temperature fluidity of crude oil and had better performance than EVAL-GO at the same addition level. The best effect was achieved at the dosing concentration of 400 ppm, which reduced the pour point by 13 ℃ and the low-temperature viscosity by 85.4%. The nanocomposites dispersed in the oil phase influenced the precipitation and crystallization of wax molecules through heterogeneous crystallization templates, which led to the increase of wax crystal size and compact structure and changed the wax crystal morphology, which had a better effect on the rheological properties of waxy oil.展开更多
The high effective nano-hybrid pour point depressant(PPD)has attracted extensive attention for its po-tential application in improving the cold flow properties of diesel fuel.In this paper,the nano-hybrid PPD was prep...The high effective nano-hybrid pour point depressant(PPD)has attracted extensive attention for its po-tential application in improving the cold flow properties of diesel fuel.In this paper,the nano-hybrid PPD was prepared by melt-blending method using three different alkyl chain lengths(i.e.,tetradecyl,hexade-cyl,and octodecyl)of n-alkyl methacrylate-maleic anhydride copolymers(R 1 MC-MA,R 1=C_(14),C_(16),C_(18))and SiO_(2)nanoparticles.The effect of those nano-hybrid PPDs on the cold filter plugging point(CFPP)and solidifying point(SP)depressing of diesel fuel were studied.Results indicated that nano-hybrid PPD showed much better performance on diesel fuel.The diesel fuel treated with 0.2 wt%C_(14)MC-MA/SiO_(2)nano-hybrid PPD exhibited the best depression in CFPP and SP by 6℃ and 18℃,respectively,which higher than that of single C 14 MC-MA.Viscosity-temperature curves and polarized optical microscopy were conducted to explore the performance mechanism;and results presented that nano-hybrid PPD of C_(14)MC-MA/SiO_(2)could effectively lower the low-temperature viscosity,and modify the crystallization behavior and crystal morphology of diesel.Therefore,the cold flow properties of diesel were significantly improved.展开更多
A bipolymer maleic anhydride-methyl acrylate （MAMA） was synthesized from maleic anhydride and methyl acrylate based on molecular design.MAMA further reacted with oleylamine or octadecyl alcohol to generate two comb ...A bipolymer maleic anhydride-methyl acrylate （MAMA） was synthesized from maleic anhydride and methyl acrylate based on molecular design.MAMA further reacted with oleylamine or octadecyl alcohol to generate two comb polymers called Oleamide-MAMA （NMAMA） and OctadecanolMAMA （OMAMA）,respectively.The structure of both the polymers was confirmed by their infrared spectral analysis （IR）,gel permeation chromatography analysis （GPC） and differential scanning calorimeter （DSC）.Moreover,the pour point depressing （PPD） properties of these comb polymers were examined experimentally.Experimental results showed that besides the molecular weight and concentration of the polymers,the length of side chains and the number of functional groups also had great influence on the pour point depressing performance.The π bonds and hydrogen bonds between depressants were the key factors for improving the pour point depressing properties.These results suggest that both OMAMA and NMAMA are potential pour point depressants for industry.展开更多
Taking into account the actual crude slate processed at the refinery, it is necessary to make reasonable combination and blending of crude oils. In order to cope with high wax content in diesel fuel it is proposed to ...Taking into account the actual crude slate processed at the refinery, it is necessary to make reasonable combination and blending of crude oils. In order to cope with high wax content in diesel fuel it is proposed to appropriately regulate the refining process scheme and add additives to refined products. This measure after being applied in the production practice has brought about good results and has met the needs of commercial production.展开更多
Polymer of n-alkyl substituted acrylate （PA） with the alkyl side chains C16- 30 were synthesized. Their crystallinity, solubility and effect on pour point depression were studied. Results showed that only carbon ato...Polymer of n-alkyl substituted acrylate （PA） with the alkyl side chains C16- 30 were synthesized. Their crystallinity, solubility and effect on pour point depression were studied. Results showed that only carbon atoms located far away from polar groups of PAL pour point depressants participated in crystallization. When the number of carbon atoms that participated in crystallization is about three fourths of the average carbon number of wax in crude, the effect of PA is the best. The molecular weight distribution of PA pour point depressant has little influence on the effect of pour point depression, and the average molecular weight of PA in the range of （ 1.5- 2.2）× 10^4 shows the best effect. The introduction of polar groups into the molecule of PA can improve its performance. However, a too high content of polar groups in PA would cause deterioration, and even lead to loss of PA＇s performance for pour point depression.展开更多
EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar ...EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar groups to enforce its adaptability and effect of waxy oil.The pure amine,maleicanhydride and their reaction product were tested using infrared spectra and the NMR spectral.The results show that when the modified EVA is added into oil,the wax deposits not only on the main chain but also on the side chains.And the polar groups have the function to avoid and resist the wax crystals connection each other to form the net.Using the reaction product of maleicanhydride and high carbonic amine(C12,C16,C18 amine) as the graft component,the toluene as the solvent and BPO as the initiator,the series of new EVA graft copolymer with special side chains are prepared under controlled condition.A series of cylmaleimide exist indeed in modified EVA and the highest grafted percentage is 18.8%.EVA-16,the new graft copolymer,is better than EVA about 3 ℃ more in depressant the pour-point of Daqing waxy crude oil.展开更多
Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorpt...Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorption behavior of these surfactants at oil/air interface was investigated by measuring the surface tension and interfacial tension as function of concentration. Surface properties, in particular the critical micelle concentration (CMC), the maximum surface excess (ΓCMC) and the minimum surface area (AMIN) were measured. It is found that the surface and thermodynamic properties of the prepared surfactants depend on their hydrocarbon chain length. Also it is found that there is a good relation between surface properties of the additive and their efficiency in depressing the pour point. The mechanism of the depressants action has been suggested according the adsorption of each additive. Adsorption of the additive on the surface of the wax particles inhibits their growth and alters the crystal habits through micelle core. As the results the surface and thermodynamic parameters confirm the suggested mechanism and the decreasing of pour point. This is resulted in a multilayer, more isotropic wax crystal, and thus only a fixed amount of wax separates at any given temperatures. The results were discussed in terms of adsorption isotherm.展开更多
The low temperature flow properties of synthetic esters were investigated based on molecular dynamics simulations,and the influence of the molecular structure of pen-taerythritol esters on the pour point was explored....The low temperature flow properties of synthetic esters were investigated based on molecular dynamics simulations,and the influence of the molecular structure of pen-taerythritol esters on the pour point was explored.When the carbon number and parity of the ester chain are the same,the pour point of the ester with a branched chain is relatively low.The pour point is related to the position of the branched chain,which near the ester group or methyl group is slightly less effective in reducing the pour point than in theβ-C position.When the number of carbons in the ester chain increases from an even to an odd number(from 6 to 7,or from 8 to 9),the pour point rises by approximately 14.5℃(from−47.65℃ to−33.15℃)or 9.5℃(from−9.65℃ to−0.15℃).When the number of carbons increases from odd to even numbers(from 7 to 8,or from 9 to 10),the pour point rises by approximately 23.5℃(from−33.15℃ to−9.65℃)or 15.5℃(−0.15℃ to 15.35℃).The branched-chain modification method for reducing the pour point of pentaerythritol ester has been proposed.The pour point of the pentaerythritol ester was−40℃ when the percentage of branched chain acid in the raw material was 10%and 15%.展开更多
An experimental study was conducted to investigate the effects of four different additives on pour point and cloud point temperatures of a diesel fuel.Sample mixtures were prepared in different volumetric percentages ...An experimental study was conducted to investigate the effects of four different additives on pour point and cloud point temperatures of a diesel fuel.Sample mixtures were prepared in different volumetric percentages of four different additives(Ethanol,Toluene,n-Heptane and Xylene)and diesel fuel mixture.Pour point and cloud point temperatures of the blends were measured using standard ASTM D2500 and ASTM D97-96a methods,respectively.Introducing the additives to the diesel fuel did not lead to a significant reduction in cloud point temperature of the fuel.In fact,the greatest obtained reduction in cloud point temperature was achieved using 20 vol%or more of Toluene-diesel fuel mixtures.Although cloud points did not change significantly,even the slightest amounts of additives caused a high reduction in the pour point temperature of the fuel.Ethanol was the most effective additive in lowering the pour point temperature of the fuel.A 20%ethanol-fuel mixture caused nearly a 30reduction in the fuel pour point temperature.Therefore,knowing that none of the additives has a significant effect on cloud point temperature,while the greatest reduction in pour point temperature is achieved using ethanol even in low Vol%s,it can be concluded that the most efficient additive among these four additives to alter cold flow properties of a certain diesel fuel is Ethanol.展开更多
基金supported by the National Natural Science Foundation of China(No.52076036)supported by the National Natural Science Foundation of China(No.52174020).
文摘Modified ethylene-vinyl acetate copolymer(EVAM)and amino-functionalized nano-silica(NSiO_(2))par-ticles were employed as the base materials for the synthesis of the nanocomposite pour point depressant designated as EVAM-g-NSiO_(2).This synthesis involved a chemical grafting process within a solution system,followed by a structural characterization.Moreover,combining macro-rheological performance with microscopic structure observation,the influence of the nanocomposite pour point depressant on the rheological properties of the model waxy oil system was investigated.The results indicate that when the mass ratio of NSiO_(2) to EVAM is 1:100,the prepared EVAM-g-NSiO_(2) nanocomposite pour point depressant exhibits excellent pour point reduction and viscosity reduction properties.Moreover,the nanocomposite pour point depressant obtained through a chemical grafting reaction demonstrates structural stability(the bonding between the polymer and nanoparticles is stable).The pour points of model waxy oils doped with 500 mg/kg ethylene-vinyl acetate copolymer(EVA),EVAM,and EVAM/SiO_(2) were reduced from 34℃ to 23,20,and 21℃,respectively.After adding the same dosage of EVAM-g-NSiO_(2) nanocomposite pour point depressant,the pour point of the model wax oil decreased to 12℃ and the viscosity at 32℃ decreased from 2399 to 2396.9 mPa·s,achieving an impressive viscosity reduction rate of 99.9%.Its performance surpassed that of EVA,EVAM,and EVAM/SiO_(2).The EVAM-g-NSiO_(2) dispersed in the oil phase acts as the crystallization nucleus for wax crystals,resulting in a dense structure of wax crystals.The compact wax crystal blocks are difficult to overlap with each other,pre-venting the formation of a three-dimensional network structure,thereby improving the low-temperature flowability of the model waxy oil.
文摘Pour point depressants （PPD） are used to improve the theology of waxy crude. The affect of various factors on the theological properties, and the thermal characteristics of waxy crude treated by PPD have been investigated. The conclusions are as follows： PPD can reduce the pour point and abnormal point of waxy crude, broaden the temperature range of Newtonian fluid of waxy crude, and lower greatly the viscosity of non-Newtonian fluid of waxy crude. The influence of reheating and high-rate shear on the effect of PPD mainly depends on their temperature. When the reheating temperature is more than the abnormal point of crude by 10℃, the reheating process has little effect on the modification effect of PPD. However, when the reheating temperature is below the abnormal point of crude, the reheating process will reduce the modification effect of PPD. When temperature is above the abnormal point of crude, the high-rate shear has little effect on the modification effect of PPD. At a temperature range where a lot of wax is precipitating, high-rate shear will greatly reduce the modification effect of PPD.
文摘The nanocomposite EVAL-CNT was produced by chemical grafting in the solution system through the esterification of ethylene-vinyl alcohol copolymer (EVAL) and carboxylated multi-walled carbon nanotubes (O-MWCNT), and its structural properties were characterized. The improvement of the rheological properties of the waxy oil system by the novel pour point depressant was investigated using macroscopic rheological measurements and microscopic observations. The results showed that EVAL-CNT nanocomposite pour point depressant (PPD) could significantly reduce the pour point and improve the low temperature fluidity of crude oil and had better performance than EVAL-GO at the same addition level. The best effect was achieved at the dosing concentration of 400 ppm, which reduced the pour point by 13 ℃ and the low-temperature viscosity by 85.4%. The nanocomposites dispersed in the oil phase influenced the precipitation and crystallization of wax molecules through heterogeneous crystallization templates, which led to the increase of wax crystal size and compact structure and changed the wax crystal morphology, which had a better effect on the rheological properties of waxy oil.
基金supported by the National Natural Science Foundation of China(Nos.22008155,22075183,21878188 and 21975161)Chenguang Program of Shanghai Education Devel-opment Foundation and Shanghai Municipal Education Commis-sion(No.19CG69).
文摘The high effective nano-hybrid pour point depressant(PPD)has attracted extensive attention for its po-tential application in improving the cold flow properties of diesel fuel.In this paper,the nano-hybrid PPD was prepared by melt-blending method using three different alkyl chain lengths(i.e.,tetradecyl,hexade-cyl,and octodecyl)of n-alkyl methacrylate-maleic anhydride copolymers(R 1 MC-MA,R 1=C_(14),C_(16),C_(18))and SiO_(2)nanoparticles.The effect of those nano-hybrid PPDs on the cold filter plugging point(CFPP)and solidifying point(SP)depressing of diesel fuel were studied.Results indicated that nano-hybrid PPD showed much better performance on diesel fuel.The diesel fuel treated with 0.2 wt%C_(14)MC-MA/SiO_(2)nano-hybrid PPD exhibited the best depression in CFPP and SP by 6℃ and 18℃,respectively,which higher than that of single C 14 MC-MA.Viscosity-temperature curves and polarized optical microscopy were conducted to explore the performance mechanism;and results presented that nano-hybrid PPD of C_(14)MC-MA/SiO_(2)could effectively lower the low-temperature viscosity,and modify the crystallization behavior and crystal morphology of diesel.Therefore,the cold flow properties of diesel were significantly improved.
文摘A bipolymer maleic anhydride-methyl acrylate （MAMA） was synthesized from maleic anhydride and methyl acrylate based on molecular design.MAMA further reacted with oleylamine or octadecyl alcohol to generate two comb polymers called Oleamide-MAMA （NMAMA） and OctadecanolMAMA （OMAMA）,respectively.The structure of both the polymers was confirmed by their infrared spectral analysis （IR）,gel permeation chromatography analysis （GPC） and differential scanning calorimeter （DSC）.Moreover,the pour point depressing （PPD） properties of these comb polymers were examined experimentally.Experimental results showed that besides the molecular weight and concentration of the polymers,the length of side chains and the number of functional groups also had great influence on the pour point depressing performance.The π bonds and hydrogen bonds between depressants were the key factors for improving the pour point depressing properties.These results suggest that both OMAMA and NMAMA are potential pour point depressants for industry.
文摘Taking into account the actual crude slate processed at the refinery, it is necessary to make reasonable combination and blending of crude oils. In order to cope with high wax content in diesel fuel it is proposed to appropriately regulate the refining process scheme and add additives to refined products. This measure after being applied in the production practice has brought about good results and has met the needs of commercial production.
文摘Polymer of n-alkyl substituted acrylate （PA） with the alkyl side chains C16- 30 were synthesized. Their crystallinity, solubility and effect on pour point depression were studied. Results showed that only carbon atoms located far away from polar groups of PAL pour point depressants participated in crystallization. When the number of carbon atoms that participated in crystallization is about three fourths of the average carbon number of wax in crude, the effect of PA is the best. The molecular weight distribution of PA pour point depressant has little influence on the effect of pour point depression, and the average molecular weight of PA in the range of （ 1.5- 2.2）× 10^4 shows the best effect. The introduction of polar groups into the molecule of PA can improve its performance. However, a too high content of polar groups in PA would cause deterioration, and even lead to loss of PA＇s performance for pour point depression.
文摘EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar groups to enforce its adaptability and effect of waxy oil.The pure amine,maleicanhydride and their reaction product were tested using infrared spectra and the NMR spectral.The results show that when the modified EVA is added into oil,the wax deposits not only on the main chain but also on the side chains.And the polar groups have the function to avoid and resist the wax crystals connection each other to form the net.Using the reaction product of maleicanhydride and high carbonic amine(C12,C16,C18 amine) as the graft component,the toluene as the solvent and BPO as the initiator,the series of new EVA graft copolymer with special side chains are prepared under controlled condition.A series of cylmaleimide exist indeed in modified EVA and the highest grafted percentage is 18.8%.EVA-16,the new graft copolymer,is better than EVA about 3 ℃ more in depressant the pour-point of Daqing waxy crude oil.
文摘Some amphoteric surfactants (N-Decyl-N-benzyl-N-methylglycine(AB) and N-Dodecyl-N-benzyl-N-methylglycine(CD) were prepared in the laboratory. The physicochemical chemical characteristics were investigated. The adsorption behavior of these surfactants at oil/air interface was investigated by measuring the surface tension and interfacial tension as function of concentration. Surface properties, in particular the critical micelle concentration (CMC), the maximum surface excess (ΓCMC) and the minimum surface area (AMIN) were measured. It is found that the surface and thermodynamic properties of the prepared surfactants depend on their hydrocarbon chain length. Also it is found that there is a good relation between surface properties of the additive and their efficiency in depressing the pour point. The mechanism of the depressants action has been suggested according the adsorption of each additive. Adsorption of the additive on the surface of the wax particles inhibits their growth and alters the crystal habits through micelle core. As the results the surface and thermodynamic parameters confirm the suggested mechanism and the decreasing of pour point. This is resulted in a multilayer, more isotropic wax crystal, and thus only a fixed amount of wax separates at any given temperatures. The results were discussed in terms of adsorption isotherm.
基金National Natural Science Foundation of China,Grant/Award Number:52130707Fundamental Research Funds for the Central Universities,Grant/Award Number:2022CDJJJ-012111 Project of the Ministry of Education,China,Grant/Award Number:BP0820005。
文摘The low temperature flow properties of synthetic esters were investigated based on molecular dynamics simulations,and the influence of the molecular structure of pen-taerythritol esters on the pour point was explored.When the carbon number and parity of the ester chain are the same,the pour point of the ester with a branched chain is relatively low.The pour point is related to the position of the branched chain,which near the ester group or methyl group is slightly less effective in reducing the pour point than in theβ-C position.When the number of carbons in the ester chain increases from an even to an odd number(from 6 to 7,or from 8 to 9),the pour point rises by approximately 14.5℃(from−47.65℃ to−33.15℃)or 9.5℃(from−9.65℃ to−0.15℃).When the number of carbons increases from odd to even numbers(from 7 to 8,or from 9 to 10),the pour point rises by approximately 23.5℃(from−33.15℃ to−9.65℃)or 15.5℃(−0.15℃ to 15.35℃).The branched-chain modification method for reducing the pour point of pentaerythritol ester has been proposed.The pour point of the pentaerythritol ester was−40℃ when the percentage of branched chain acid in the raw material was 10%and 15%.
文摘An experimental study was conducted to investigate the effects of four different additives on pour point and cloud point temperatures of a diesel fuel.Sample mixtures were prepared in different volumetric percentages of four different additives(Ethanol,Toluene,n-Heptane and Xylene)and diesel fuel mixture.Pour point and cloud point temperatures of the blends were measured using standard ASTM D2500 and ASTM D97-96a methods,respectively.Introducing the additives to the diesel fuel did not lead to a significant reduction in cloud point temperature of the fuel.In fact,the greatest obtained reduction in cloud point temperature was achieved using 20 vol%or more of Toluene-diesel fuel mixtures.Although cloud points did not change significantly,even the slightest amounts of additives caused a high reduction in the pour point temperature of the fuel.Ethanol was the most effective additive in lowering the pour point temperature of the fuel.A 20%ethanol-fuel mixture caused nearly a 30reduction in the fuel pour point temperature.Therefore,knowing that none of the additives has a significant effect on cloud point temperature,while the greatest reduction in pour point temperature is achieved using ethanol even in low Vol%s,it can be concluded that the most efficient additive among these four additives to alter cold flow properties of a certain diesel fuel is Ethanol.
