Plants possess a hydrophobic layer of wax on their aerial surface,consisting mainly of amorphous intra-cuticular wax and epicuticular wax crystals(Kunst and Samuels,2003).This waxy coating contains a wide variety of v...Plants possess a hydrophobic layer of wax on their aerial surface,consisting mainly of amorphous intra-cuticular wax and epicuticular wax crystals(Kunst and Samuels,2003).This waxy coating contains a wide variety of very-long-chain fatty acids(VLCFAs)and their derivatives,including alkanes,alcohols,aldehydes,esters,and ketones.展开更多
Wax gourd(Benincasa hispida)is an important cucurbit crop with economic and medicinal value.The myeloblastosis(MYB)gene family is one of the largest gene families in plants and regulates various biological processes,w...Wax gourd(Benincasa hispida)is an important cucurbit crop with economic and medicinal value.The myeloblastosis(MYB)gene family is one of the largest gene families in plants and regulates various biological processes,whereas the MYB gene family has not been systematically studied in wax gourd.In this study,we performed genome-wide identification of the MYB gene family in wax gourd and analyzed their phylogenetic relationship,MYB DNA-binding domain(MYB DBD),gene structure,protein motif,synteny,duplication mode and expression pattern.As a result,a total of 215 BhMYB genes(BhMYBs)were identified,belonging to four subfamilies:1R-,2R-,3R-and 4R-MYB subfamilies.Genes of 1R-MYB subfamily and 2R-MYB subfamily were subdivided into different subgroups respectively.The analysis of MYB DBD,gene structure and protein motif showed that the most genes in the same subgroup had similar characteristics and the 2R-MYB genes were more conserved than the 1R-MYB genes.Interestingly,the long terminal retrotransposons(LTR-RTs)were found in the long introns of several BhMYBs.The results of synteny analysis showed that there were more syntenic gene pairs between wax gourd and other cucurbit crops,while the least number of syntenic gene pairs existed between wax gourd and rice.Gene duplication was the main reason for the expansion of the MYB gene family in wax gourd,with the transposed duplication(TRD)mode contributing more.All duplication BhMYB genes were under purifying selection pressure.Further expression analysis showed that many BhMYBs exhibited obvious tissue-specific expression and several BhMYBs were significantly induced by one or more abiotic stresses.BhMYB79 was particularly expressed in roots and significantly induced by salt,drought,cold and heat stresses,overexpression of which led to reduced tolerance to salt stress in Arabidopsis.In conclusion,our results provide a systematic analysis of wax gourd MYB gene family and facilitate the biological role study of BhMYB79 during wax gourd salt stress response process.展开更多
The synergistic regulatory effect of the ethylene transcription factor MdERF2 and ubiquitin ligase MdPUB17 on apple(Malus domestica)epidermal wax was examined by transferring the pRI101-MdPUB17-MdERF2 dual overexpress...The synergistic regulatory effect of the ethylene transcription factor MdERF2 and ubiquitin ligase MdPUB17 on apple(Malus domestica)epidermal wax was examined by transferring the pRI101-MdPUB17-MdERF2 dual overexpression vector(PUB17-ERF2),the empty vector(pRI101),the pRI101-MdPUB17 overexpression vector(PUB17),and the pRI101-MdERF2 overexpression vector(ERF2)into Agrobacterium tumefaciens,respectively,to infect apple callus and fruits with water as the control(CK).The levels of expression of the genes related to the biosynthesis,transport,composition,content,and structure of wax in the callus and/or fruits were studied under different treatments.The synergistic treatment of PUB17-ERF2 resulted in a decrease in the expression levels of MdCER1,MdCER6,MdLACS2,MdWSD1,MdABCG11,MdPAS2,MdFATB,and MdKASII genes as induced by the sole treatment of ERF2.Moreover,in the treatment of PUB17-ERF2,the mass distribution density of the wax was observed to be intermediate between the ERF2 and PUB17 treatments.Furthermore,ERF2 was found to increase the contents of alkanes,alcohols,and ketones,while significantly decreasing the contents of fatty acids and esters.In contrast,PUB17 responded oppositely.When treated with PUB17-ERF2,the effects of PUB17 and ERF2 were observed to counteract each other,which resulted in intermediate levels of these compounds.Additionally,the fruit in the ERF2,PUB17 and PUB17-ERF2 treatments had a different waxy microstructure.Overall,the findings indicate that both ERF2 and PUB17 have an impact on the gene expression,wax composition,content,and microstructure in apple epidermis.Importantly,the co-expression of MdPUB17 and MdERF2 demonstrates their synergistic regulation of the biosynthesis of wax in the apple epidermis.展开更多
Starting from the perspective of formula and efficacy,orthogonal experiments were first performed to explore the optimal ratio of three raw materials that potentially affect breaking force of lipsticks,verification ex...Starting from the perspective of formula and efficacy,orthogonal experiments were first performed to explore the optimal ratio of three raw materials that potentially affect breaking force of lipsticks,verification experiment on humans was then conducted to test the efficacy of the lipstick formula.Results showed that when the ratio of carnauba wax,shea butter and myristyl isopropyl ester was 3∶7∶3,the breaking force was optimal.After the subjects used the lipstick formula for 14 days,the moisture content of the lip stratum corneum significantly increased by 23.51% (P﹤0.05),the transepidermal water loss (TEWL) rate significantly decreased by 20.61%,the skin glossiness increased significantly by 9.88%,and the skin scale index decreased significantly by 55.76%.展开更多
Ethylene response factors 2(ERF2) are essential for plant growth, fruit ripening, metabolism, and resistance tostress. In this study, the expression levels of the genes for MdERF2 implicated in the biosynthesis, compo...Ethylene response factors 2(ERF2) are essential for plant growth, fruit ripening, metabolism, and resistance tostress. In this study, the expression levels of the genes for MdERF2 implicated in the biosynthesis, compositionand ultrastructure of fruit cuticular wax in apple(Malus domestica) were studied by the transfection of apple fruitand/or calli with MdERF2-overexpression(ERF2-OE) and MdERF2-interference(ERF2-AN) vectors. In addition,the direct target genes of MdERF2 related to wax biosynthesis were identified using electrophoretic mobility shiftassays(EMSAs) and dual-luciferase reporter(DLR) assays. The findings indicated that the expression levels offour wax biosynthetic genes, long-chain acyl-CoA synthetase 2(MdLACS2), eceriferum 1(MdCER1), eceriferum4(MdCER4), and eceriferum 6(MdCER6), were upregulated by ERF2-OE. In contrast, the expression levels ofthese genes were inhibited when MdERF2 was silenced. Furthermore, the overall structure and accumulationof fruit cuticular wax were influenced by the expression level of MdERF2. Treatment with ERF2-OE significantlyincreased the proportions of alkanes and ketones and reduced the proportions of fatty acids and esters. In addition,the EMSAs and DLR assays demonstrated that MdERF2 could bind directly to GCC-box elements in the promotersof MdLACS2, MdCER1, and MdCER6 to activate their transcription. These results confirmed that MdERF2 targetsthe up-regulation of expression of the MdLACS2, MdCER1, and MdCER6 genes, thereby altering the composition,content, and microstructure of apple epidermal wax.展开更多
This study aimed to systematically evaluate the clinical efficacy of combining wax therapy with conventional drug therapy for rheumatoid arthritis(RA)and to provide evidence supporting its clinical application.A compr...This study aimed to systematically evaluate the clinical efficacy of combining wax therapy with conventional drug therapy for rheumatoid arthritis(RA)and to provide evidence supporting its clinical application.A comprehensive search was conducted across PubMed,Cochrane Library,China Biomedical Literature Database(CBM),China National Knowledge Infrastructure(CNKI),Wanfang,and VIP databases from their inception to May 2024.Randomized controlled trials(RCTs)investigating the combination of wax therapy and conventional drug therapy for RA were included in the analysis.Statistical analysis was performed using Review Manager 5.3 software.Nine studies,encompassing a total of 843 patients,were included.The results demonstrated that the combination therapy significantly improved clinical efficacy compared to conventional drug therapy alone[RR=1.22,95%CI(1.11,1.34)].Moreover,the combination therapy led to notable improvements in DAS 28 scores[MD=-0.90,95%CI(-1.23,-0.57),P<0.00001],VAS scores[MD=-0.90,95%CI(-1.13,-0.66),P<0.00001],reduction in joint tenderness[MD=-1.27,95%CI(-1.81,-0.72),P<0.00001],decreased duration of morning stiffness[MD=-25.47,95%CI(-34.33,-16.61),P<0.00001],and lowered C-reactive protein levels[MD=-6.29,95%CI(-12.02,-0.57),P<0.05].In conclusion,wax therapy combined with conventional anti-rheumatic drugs significantly enhanced the clinical outcomes for RA patients by alleviating symptoms,reducing joint pain and morning stiffness,and decreasing inflammatory markers more effectively than conventional drug therapy alone.展开更多
A hard problem that hinders the movement of waxy crude oil is wax deposition in oil pipelines.To ensure the safe operation of crude oil pipelines,an accurate model must be developed to predict the rate of wax depositi...A hard problem that hinders the movement of waxy crude oil is wax deposition in oil pipelines.To ensure the safe operation of crude oil pipelines,an accurate model must be developed to predict the rate of wax deposition in crude oil pipelines.Aiming at the shortcomings of the ENN prediction model,which easily falls into the local minimum value and weak generalization ability in the implementation process,an optimized ENN prediction model based on the IRSA is proposed.The validity of the new model was confirmed by the accurate prediction of two sets of experimental data on wax deposition in crude oil pipelines.The two groups of crude oil wax deposition rate case prediction results showed that the average absolute percentage errors of IRSA-ENN prediction models is 0.5476% and 0.7831%,respectively.Additionally,it shows a higher prediction accuracy compared to the ENN prediction model.In fact,the new model established by using the IRSA to optimize ENN can optimize the initial weights and thresholds in the prediction process,which can overcome the shortcomings of the ENN prediction model,such as weak generalization ability and tendency to fall into the local minimum value,so that it has the advantages of strong implementation and high prediction accuracy.展开更多
Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition lay...Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device.Just as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature.Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness.In addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil ratios.The bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate variations.Furthermore,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism.Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs.Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.展开更多
The cuticular wax,acting as the ultimate defense barrier,is essential for the normal morphogenesis of plant organs.Despite this importance,the connection between wax composition and leaf development has not been thoro...The cuticular wax,acting as the ultimate defense barrier,is essential for the normal morphogenesis of plant organs.Despite this importance,the connection between wax composition and leaf development has not been thoroughly explored.In this study,we characterized a new maize mutant,ragged leaf4(rgd4),which exhibits crinkled and ragged leaves starting from the sixth leaf stage.The phenotype of rgd4 is conferred by ZmCER1,which encoding an aldehyde decarbonylase involved in wax biosynthesis.ZmCER1 function deficient mutant displayed reduced cuticular wax density and disordered bulliform cells(BCs),while ZmCER1 overexpressing plants exhibited the opposite effects,indicating that ZmCER1 regulates cuticular wax biosynthesis and BCs development.Additionally,as the density of cuticular wax increased,the water loss rate of detached leaf decreases,suggesting that ZmCER1 is positively correlated with plant drought tolerance.展开更多
High content of asphaltenes and waxes leads to the high pour point and the poor flowability of heavy oil,which is adverse to its efficient development and its transportation in pipe.Understanding the interaction mecha...High content of asphaltenes and waxes leads to the high pour point and the poor flowability of heavy oil,which is adverse to its efficient development and its transportation in pipe.Understanding the interaction mechanism between asphaltene-wax is crucial to solve these problems,but it is still unclear.In this paper,molecular dynamics simulation was used to investigate the interaction between asphaltenewax and its effects on the crystallization behavior of waxes in heavy oil.Results show that molecules in pure wax are arranged in a paralleled geometry.But wax molecules in heavy oil,which are close to the surface of asphaltene aggregates,are bent and arranged irregularly.When the mass fraction of asphaltenes in asphaltene-wax system(ω_(asp))is 0-25 wt%,the attraction among wax molecules decreases and the bend degree of wax molecules increases with the increase ofω_(asp).Theω_(asp)increases from 0 to 25 wt%,and the attraction between asphaltene-wax is stronger than that among waxes.This causes that the wax precipitation point changes from 353 to 333 K.While theω_(asp)increases to 50 wt%,wax molecules are more dispersed owing to the steric hindrance of asphaltene aggregates,and the interaction among wax molecules transforms from attraction to repulsion.It causes that the ordered crystal structure of waxes can't be formed at normal temperature.Simultaneously,the asphaltene,with the higher molecular weight or the more hetero atoms,has more obvious inhibition to the formation of wax crystals.Besides,resins also have an obvious inhibition on the wax crystal due to the formation of asphalteneresin aggregates with a larger radius.Our results reveal the interaction mechanism between asphaltene-wax,and provide useful guidelines for the development of heavy oil.展开更多
Drought-resistant plants exhibit strong water retention capability.In this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid leaves.Morphological comparisons and physiological co...Drought-resistant plants exhibit strong water retention capability.In this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid leaves.Morphological comparisons and physiological comparisons of diploid and autotetraploid leaves showed that the autotetraploid leaves had thicker leaf cuticles and more leaf wax accumulation than the diploid leaves,which could reduce cuticle permeability and improve the drought tolerance of leaves.In this study,the cuticular wax crystalloids on the adaxial and abaxial sides of young and mature jujube leaves were observed in the two ploidy types,and unique cuticular wax crystalloids covering a large area of the cuticle on autotetraploid sour jujube leaves may provide an advantage in reducing leaf non-stomata transpiration and improving plant drought tolerance.Based on the transcriptome,115 differentially expressed genes between diploids and autotetraploids were further analyzed and found to be involved in the accumulation of cuticular wax components,including terpenoids,fatty acids,and lipids,as well as ABC transporter and wax biosynthetic process.Finally,14 genes differentially expressed between glossy autotetraploid leaves and nonglossy diploid leaves,such as LOC107414787,LOC107411574 and LOC107413721,were screened as candidate genes by qRT-PCR analysis.This findings provided insights into how polyploidization improved drought tolerance.展开更多
The gelation of crude oil with high wax and asphaltene content at low temperatures often results in the block of transportation pipeline in Africa. In recent years, it was reported that surface hydrophobicmodified nan...The gelation of crude oil with high wax and asphaltene content at low temperatures often results in the block of transportation pipeline in Africa. In recent years, it was reported that surface hydrophobicmodified nanoparticles have important applications in crude oil flow modification. In this work, four kinds of core-shell hybride nanoparticles by grafting poly(octadecyl, docosyl acrylate) and poly(acrylate-α-olefin) onto the surface of nano-sized SiO_(2) were synthesized by grafting polymerization method.The chemical structure of nanoparticles was analyzed by Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM) and thermogravimetric analysis(TGA). The rheological behaviors of crude oil and precipitation of asphaltenes in the presence of nanoparticles were studied by measuring the viscose-temperature relationship curve, the cumulative wax precipitation amount, and morphology of waxes and asphaltenes. The results indicate that the docosyl polyacrylate@SiO_(2) nanoparticle(PDA@SiO_(2)) can reduce the cumulative wax precipitation amount of crude oil by 72.8%, decline the viscosity of crude oil by 85.6% at 20℃, reduce the average size of wax crystals by 89.7%, and inhibit the agglomeration of asphaltene by 74.8%. Therefore, the nanoparticles not only adjust the crystalline behaviors of waxes, but also inhibit the agglomeration of asphaltenes. Apparently, core-shell hybride nanoparticles provides more heterogeneous nucleation sites for the crystallization of wax molecules,thus inhibiting the formation of three-dimensional network structure. The core-shell polymer@SiO_(2) hybride nanoparticles are one of promising additives for inhibiting crystallization of waxes and agglomeration of asphaltenes in crude oil.展开更多
Ethylene-vinyl acetate copolymer(EVA) as a kind of effective polymeric pour point depressant has been extensively used in the pipeline transportation of crude oil to inhibit wax deposition and improve the low temperat...Ethylene-vinyl acetate copolymer(EVA) as a kind of effective polymeric pour point depressant has been extensively used in the pipeline transportation of crude oil to inhibit wax deposition and improve the low temperature fluidity of crude oil. In this work, molecular dynamics simulations were performed to investigate the effect of EVA on wax-hydrate coexistence system to evaluate the application potentiality of EVA to the flow assurance of deep-sea oil-gas-water multiphase flow system. Our simulation results reveal that wax molecules gradually stretched and stacked from random coiling to a directional and ordered crystalline state during the process of wax solidification. The strong affinity of polar vinyl acetate side chains of EVA to neighboring water molecules made the EVA molecule prefer being in a curly state,which disrupted the ordered crystallization of surrounding wax molecules and delayed the solidification rate of wax cluster. In addition, it is found that EVA cocrystallized with wax molecules to form eutectic when the wax was fully solidified. The simulation results of hydrate nucleation and growth show that the EVA molecule displayed a two-sided effect on gas adsorption of wax crystals, which was the key factor that affected the nucleation and growth of hydrates in the methane-water system. The nonpolar hydrocarbon backbone of EVA increased the diffusion rate of methane and water, allowing more methane to diffuse to the surface of wax crystals, reducing the methane concentration in aqueous solutions and inhibiting the hydrate formation. On the other hand, the nonpolar vinyl acetate chains had a repulsive effect on methane, which reduced the adsorption area of methane on the eutectic surface and decreased the adsorption threshold value of the wax crystal. The excluded methane molecules would continue dissociating in the aqueous phase and participating in the nucleation and growth process of hydrates.Therefore, the probability of hydrate formation would be increased. It was worth noting that the inhibition performance of EVA on hydrate formation mainly played a significant role in the system with small wax crystal, while its hydrate promotion effect played a dominant role in the system with lager wax crystal. In summary, EVA could significantly inhibit both of the wax and hydrate deposition for the waxgas-water multiphase system with low wax content. When the wax content in the system was high, the role of EVA was mainly played in the alleviation of wax crystallization rather than the gas hydrates. The results of the present work can contribute to a better understanding of EVA on wax deposition and hydrate formation, and provide theoretical support of the potential industrial applications of EVA.展开更多
The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffi...The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffin wax was modified through four types of modifiers,including organic high-molecular-mass resins,plasticizers,surfactants and lubricants.The qualitative screening of resin types was explored and an orthogonal experiment involving the combination of these four paraffin wax modifiers was conducted to obtain an optimized quantitative ratio of modifiers.The results reveal that the insertion of the small molecule chain of resin into the interstitial spaces of paraffin wax crystals is likely a crucial factor for improving the compatibility between the resin and paraffin wax.Through orthogonal experiments,the optimized formulation for the forming agent is determined:100 parts of 58#paraffin wax,15 parts of EVA-2,4 parts of DPHP,4 parts of oleic acid amide and 2 parts of stearic acid.This optimized formulation is applied to industrial production at one Chinese company,and qualified deep well-shaped cemented carbide products are achieved,which contain 90wt%WC and 10wt%Co.展开更多
Microbial enhanced oil recovery(MEOR)is a cost effective and efficient method for recovering residual oil.However,the presence of wax(paraffin)in residual oil can substantially reduce the efficiency of MEOR.Therefore,...Microbial enhanced oil recovery(MEOR)is a cost effective and efficient method for recovering residual oil.However,the presence of wax(paraffin)in residual oil can substantially reduce the efficiency of MEOR.Therefore,microbial dewaxing is a critical process in MEOR.In this study,a bacterial dewaxing agent of three spore-forming bacteria was developed.Among these bacteria,Bacillus subtilis GZ6 produced the biosurfactant surfactin.Replacing the promoter of the surfactin synthase gene cluster(srfA),increased the titer of surfactin in this strain from 0.33 g/L to 2.32 g/L.The genetically modified strain produced oil spreading rings with diameters increasing from 3.5±0.1 to 4.1±0.2 cm.The LadA F10L/N133R mutant was created by engineering an alkane monooxygenase(LadA)using site-directed mutagenesis in the Escherichia coli host.Compared to the wild-type enzyme,the resulting mutant exhibited an 11.7-fold increase in catalytic efficiency toward the substrate octadecane.When the mutant(pIMPpladA2mu)was expressed in Geobacillus stearothermophilus GZ178 cells,it exhibited a 2.0-fold increase in octadecane-degrading activity.Cultures of the two modified strains(B.subtilis GZ6(pg3srfA)and G.stearothermophilus GZ178(pIMPpladA2mu))were mixed with the culture of Geobacillus thermodenitrificans GZ156 at a ratio of 5:80:15.The resulting composition increased the rate of wax removal by 35%compared to the composition composed of three native strains.This study successfully developed a multi-strain bacterial agent with enhanced oil wax removal capabilities by genetically engineering two bacterial strains.展开更多
The phenomenon of petroleum wax deposition is very common during oil well production. When the wax molecule condenses on the surface of the pipeline, it will hinder the exploitation of crude oil, reduce the recovery r...The phenomenon of petroleum wax deposition is very common during oil well production. When the wax molecule condenses on the surface of the pipeline, it will hinder the exploitation of crude oil, reduce the recovery rate of crude oil, and may lead to the blockage of the pipeline when it is serious, so that the oil recovery work will stop. This phenomenon can be obviously changed by using wax cleaning agent. However, the low ignition point and toxicity of oil-based wax remover are not conducive to oil recovery. Therefore, a new water-based paraffin remover SGJ-1 was developed in this paper. The best formula is: wax dispersant 15%, wetting reversion agent 1%, sodium silicate 1%, alcohol cosolvent 8% and 75% water. Condensation point, wax dissolution rate and anti-wax performance of SGJ-1 water-based dewaxing and anti-waxing agent were tested by self-assembly testing device. The experimental results show that the condensation point of SGJ-1 is -34°C, the viscosity reduction effect is good under 35°C, and the wax dissolution rate is 0.0512 g/min, The highest wax prevention rate can reach 89.58% and the wax removal and wax prevention ability is excellent. Compared with other paraffin removers, SGJ-1 can also reduce the viscosity of crude oil, so it has a good development prospect.展开更多
The present study investigated the wax deposition tendencies of a light Malaysian crude oil（42.4° API）, and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowled...The present study investigated the wax deposition tendencies of a light Malaysian crude oil（42.4° API）, and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant（highest） and bio-surfactant（lowest）revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO2 nanoparticle suspension in a load ratio of 3：1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate.展开更多
Wax deposits on the wall of a crude oil pipeline are a solid wax network of fine crystals, filled with oil, resin, asphaltene and other impurities. In this paper, a series of experiments on wax deposition in a laborat...Wax deposits on the wall of a crude oil pipeline are a solid wax network of fine crystals, filled with oil, resin, asphaltene and other impurities. In this paper, a series of experiments on wax deposition in a laboratory flow loop were performed under different conditions （flow rate, temperature differential between crude oil and pipeline wall, and dissolved wax concentration gradient）, and the wax deposits were analyzed, so quantitative relationships among wax content, wax appearance temperature （WAT）, shear stress, and radial concentration gradient of dissolved wax at the solid/liquid interface were obtained. Finally, a model was established to predict WAT and the wax content of the deposit.展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant No.31972405).
文摘Plants possess a hydrophobic layer of wax on their aerial surface,consisting mainly of amorphous intra-cuticular wax and epicuticular wax crystals(Kunst and Samuels,2003).This waxy coating contains a wide variety of very-long-chain fatty acids(VLCFAs)and their derivatives,including alkanes,alcohols,aldehydes,esters,and ketones.
基金supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2020B020220003)National Natural Science Foundation of China(32202504)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515030049)Guangdong Rural Revitalization Strategy Special Project(Grant No.2023-NJS-00-003)Special fund for scientific and technological talents introduction of Guangdong Academy of Agricultural Sciences(Grant No.R2021YJ-YB2004)。
文摘Wax gourd(Benincasa hispida)is an important cucurbit crop with economic and medicinal value.The myeloblastosis(MYB)gene family is one of the largest gene families in plants and regulates various biological processes,whereas the MYB gene family has not been systematically studied in wax gourd.In this study,we performed genome-wide identification of the MYB gene family in wax gourd and analyzed their phylogenetic relationship,MYB DNA-binding domain(MYB DBD),gene structure,protein motif,synteny,duplication mode and expression pattern.As a result,a total of 215 BhMYB genes(BhMYBs)were identified,belonging to four subfamilies:1R-,2R-,3R-and 4R-MYB subfamilies.Genes of 1R-MYB subfamily and 2R-MYB subfamily were subdivided into different subgroups respectively.The analysis of MYB DBD,gene structure and protein motif showed that the most genes in the same subgroup had similar characteristics and the 2R-MYB genes were more conserved than the 1R-MYB genes.Interestingly,the long terminal retrotransposons(LTR-RTs)were found in the long introns of several BhMYBs.The results of synteny analysis showed that there were more syntenic gene pairs between wax gourd and other cucurbit crops,while the least number of syntenic gene pairs existed between wax gourd and rice.Gene duplication was the main reason for the expansion of the MYB gene family in wax gourd,with the transposed duplication(TRD)mode contributing more.All duplication BhMYB genes were under purifying selection pressure.Further expression analysis showed that many BhMYBs exhibited obvious tissue-specific expression and several BhMYBs were significantly induced by one or more abiotic stresses.BhMYB79 was particularly expressed in roots and significantly induced by salt,drought,cold and heat stresses,overexpression of which led to reduced tolerance to salt stress in Arabidopsis.In conclusion,our results provide a systematic analysis of wax gourd MYB gene family and facilitate the biological role study of BhMYB79 during wax gourd salt stress response process.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.32272384 and 32172278)。
文摘The synergistic regulatory effect of the ethylene transcription factor MdERF2 and ubiquitin ligase MdPUB17 on apple(Malus domestica)epidermal wax was examined by transferring the pRI101-MdPUB17-MdERF2 dual overexpression vector(PUB17-ERF2),the empty vector(pRI101),the pRI101-MdPUB17 overexpression vector(PUB17),and the pRI101-MdERF2 overexpression vector(ERF2)into Agrobacterium tumefaciens,respectively,to infect apple callus and fruits with water as the control(CK).The levels of expression of the genes related to the biosynthesis,transport,composition,content,and structure of wax in the callus and/or fruits were studied under different treatments.The synergistic treatment of PUB17-ERF2 resulted in a decrease in the expression levels of MdCER1,MdCER6,MdLACS2,MdWSD1,MdABCG11,MdPAS2,MdFATB,and MdKASII genes as induced by the sole treatment of ERF2.Moreover,in the treatment of PUB17-ERF2,the mass distribution density of the wax was observed to be intermediate between the ERF2 and PUB17 treatments.Furthermore,ERF2 was found to increase the contents of alkanes,alcohols,and ketones,while significantly decreasing the contents of fatty acids and esters.In contrast,PUB17 responded oppositely.When treated with PUB17-ERF2,the effects of PUB17 and ERF2 were observed to counteract each other,which resulted in intermediate levels of these compounds.Additionally,the fruit in the ERF2,PUB17 and PUB17-ERF2 treatments had a different waxy microstructure.Overall,the findings indicate that both ERF2 and PUB17 have an impact on the gene expression,wax composition,content,and microstructure in apple epidermis.Importantly,the co-expression of MdPUB17 and MdERF2 demonstrates their synergistic regulation of the biosynthesis of wax in the apple epidermis.
文摘Starting from the perspective of formula and efficacy,orthogonal experiments were first performed to explore the optimal ratio of three raw materials that potentially affect breaking force of lipsticks,verification experiment on humans was then conducted to test the efficacy of the lipstick formula.Results showed that when the ratio of carnauba wax,shea butter and myristyl isopropyl ester was 3∶7∶3,the breaking force was optimal.After the subjects used the lipstick formula for 14 days,the moisture content of the lip stratum corneum significantly increased by 23.51% (P﹤0.05),the transepidermal water loss (TEWL) rate significantly decreased by 20.61%,the skin glossiness increased significantly by 9.88%,and the skin scale index decreased significantly by 55.76%.
基金supported by the National Natural Science Foundation of China (32272384)the Natural Science Foundation of Shandong Province, China (ZR2020MC149)。
文摘Ethylene response factors 2(ERF2) are essential for plant growth, fruit ripening, metabolism, and resistance tostress. In this study, the expression levels of the genes for MdERF2 implicated in the biosynthesis, compositionand ultrastructure of fruit cuticular wax in apple(Malus domestica) were studied by the transfection of apple fruitand/or calli with MdERF2-overexpression(ERF2-OE) and MdERF2-interference(ERF2-AN) vectors. In addition,the direct target genes of MdERF2 related to wax biosynthesis were identified using electrophoretic mobility shiftassays(EMSAs) and dual-luciferase reporter(DLR) assays. The findings indicated that the expression levels offour wax biosynthetic genes, long-chain acyl-CoA synthetase 2(MdLACS2), eceriferum 1(MdCER1), eceriferum4(MdCER4), and eceriferum 6(MdCER6), were upregulated by ERF2-OE. In contrast, the expression levels ofthese genes were inhibited when MdERF2 was silenced. Furthermore, the overall structure and accumulationof fruit cuticular wax were influenced by the expression level of MdERF2. Treatment with ERF2-OE significantlyincreased the proportions of alkanes and ketones and reduced the proportions of fatty acids and esters. In addition,the EMSAs and DLR assays demonstrated that MdERF2 could bind directly to GCC-box elements in the promotersof MdLACS2, MdCER1, and MdCER6 to activate their transcription. These results confirmed that MdERF2 targetsthe up-regulation of expression of the MdLACS2, MdCER1, and MdCER6 genes, thereby altering the composition,content, and microstructure of apple epidermal wax.
基金supported by the Key Research and Development Program of Yunnan Science and Technology Department(Grant No.202303AC100326)the National Natural Science Foundation of China(Grant No.81960863)the Education Department of Yunnan Province(Grant No.2023Y0463 and 2024Y380).
文摘This study aimed to systematically evaluate the clinical efficacy of combining wax therapy with conventional drug therapy for rheumatoid arthritis(RA)and to provide evidence supporting its clinical application.A comprehensive search was conducted across PubMed,Cochrane Library,China Biomedical Literature Database(CBM),China National Knowledge Infrastructure(CNKI),Wanfang,and VIP databases from their inception to May 2024.Randomized controlled trials(RCTs)investigating the combination of wax therapy and conventional drug therapy for RA were included in the analysis.Statistical analysis was performed using Review Manager 5.3 software.Nine studies,encompassing a total of 843 patients,were included.The results demonstrated that the combination therapy significantly improved clinical efficacy compared to conventional drug therapy alone[RR=1.22,95%CI(1.11,1.34)].Moreover,the combination therapy led to notable improvements in DAS 28 scores[MD=-0.90,95%CI(-1.23,-0.57),P<0.00001],VAS scores[MD=-0.90,95%CI(-1.13,-0.66),P<0.00001],reduction in joint tenderness[MD=-1.27,95%CI(-1.81,-0.72),P<0.00001],decreased duration of morning stiffness[MD=-25.47,95%CI(-34.33,-16.61),P<0.00001],and lowered C-reactive protein levels[MD=-6.29,95%CI(-12.02,-0.57),P<0.05].In conclusion,wax therapy combined with conventional anti-rheumatic drugs significantly enhanced the clinical outcomes for RA patients by alleviating symptoms,reducing joint pain and morning stiffness,and decreasing inflammatory markers more effectively than conventional drug therapy alone.
文摘A hard problem that hinders the movement of waxy crude oil is wax deposition in oil pipelines.To ensure the safe operation of crude oil pipelines,an accurate model must be developed to predict the rate of wax deposition in crude oil pipelines.Aiming at the shortcomings of the ENN prediction model,which easily falls into the local minimum value and weak generalization ability in the implementation process,an optimized ENN prediction model based on the IRSA is proposed.The validity of the new model was confirmed by the accurate prediction of two sets of experimental data on wax deposition in crude oil pipelines.The two groups of crude oil wax deposition rate case prediction results showed that the average absolute percentage errors of IRSA-ENN prediction models is 0.5476% and 0.7831%,respectively.Additionally,it shows a higher prediction accuracy compared to the ENN prediction model.In fact,the new model established by using the IRSA to optimize ENN can optimize the initial weights and thresholds in the prediction process,which can overcome the shortcomings of the ENN prediction model,such as weak generalization ability and tendency to fall into the local minimum value,so that it has the advantages of strong implementation and high prediction accuracy.
基金supported by the National Natural Science Foundation of China(Grant No.52274061&52004039&51974037)China Postdoctoral Science Foundation(Grant No.2023T160717&2021M693908)+2 种基金CNPC Innovation Found(Grant No.2022DQ02-0501),Changzhou Applied Basic Research Program(Grant No.CJ20230030)The major project of universities affiliated with Jiangsu Province basic science(natural science)research(Grant No.21KJA440001)Jiangsu Qinglan Project,Changzhou Longcheng Talent Plan-Youth Science and Technology Talent Recruitment Project。
文摘Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device.Just as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature.Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness.In addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil ratios.The bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate variations.Furthermore,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism.Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs.Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.
基金supported by Professor Zhukuan Cheng from Institute of Genetics and Developmental Biology,Chinese Academy of Sciencessupported by the Funds of Key R&D Program of Shandong Province(2022LZGC006)Key R&D Program of Shandong Province(2023LZGC006)。
文摘The cuticular wax,acting as the ultimate defense barrier,is essential for the normal morphogenesis of plant organs.Despite this importance,the connection between wax composition and leaf development has not been thoroughly explored.In this study,we characterized a new maize mutant,ragged leaf4(rgd4),which exhibits crinkled and ragged leaves starting from the sixth leaf stage.The phenotype of rgd4 is conferred by ZmCER1,which encoding an aldehyde decarbonylase involved in wax biosynthesis.ZmCER1 function deficient mutant displayed reduced cuticular wax density and disordered bulliform cells(BCs),while ZmCER1 overexpressing plants exhibited the opposite effects,indicating that ZmCER1 regulates cuticular wax biosynthesis and BCs development.Additionally,as the density of cuticular wax increased,the water loss rate of detached leaf decreases,suggesting that ZmCER1 is positively correlated with plant drought tolerance.
基金financially supported by the Project funded by China Postdoctoral Science Foundation (NO.2022M723500)the National Natural Science Foundation of China (NO.52204069)the Sinopec Science and Technology Project of China (NO.P22015)。
文摘High content of asphaltenes and waxes leads to the high pour point and the poor flowability of heavy oil,which is adverse to its efficient development and its transportation in pipe.Understanding the interaction mechanism between asphaltene-wax is crucial to solve these problems,but it is still unclear.In this paper,molecular dynamics simulation was used to investigate the interaction between asphaltenewax and its effects on the crystallization behavior of waxes in heavy oil.Results show that molecules in pure wax are arranged in a paralleled geometry.But wax molecules in heavy oil,which are close to the surface of asphaltene aggregates,are bent and arranged irregularly.When the mass fraction of asphaltenes in asphaltene-wax system(ω_(asp))is 0-25 wt%,the attraction among wax molecules decreases and the bend degree of wax molecules increases with the increase ofω_(asp).Theω_(asp)increases from 0 to 25 wt%,and the attraction between asphaltene-wax is stronger than that among waxes.This causes that the wax precipitation point changes from 353 to 333 K.While theω_(asp)increases to 50 wt%,wax molecules are more dispersed owing to the steric hindrance of asphaltene aggregates,and the interaction among wax molecules transforms from attraction to repulsion.It causes that the ordered crystal structure of waxes can't be formed at normal temperature.Simultaneously,the asphaltene,with the higher molecular weight or the more hetero atoms,has more obvious inhibition to the formation of wax crystals.Besides,resins also have an obvious inhibition on the wax crystal due to the formation of asphalteneresin aggregates with a larger radius.Our results reveal the interaction mechanism between asphaltene-wax,and provide useful guidelines for the development of heavy oil.
基金supported by grants from the Fundamental Research Funds for the Central Universities(Grant No.2021JD02)the National Key Research and Development Program of China(Grant No.2018YFD1000607)。
文摘Drought-resistant plants exhibit strong water retention capability.In this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid leaves.Morphological comparisons and physiological comparisons of diploid and autotetraploid leaves showed that the autotetraploid leaves had thicker leaf cuticles and more leaf wax accumulation than the diploid leaves,which could reduce cuticle permeability and improve the drought tolerance of leaves.In this study,the cuticular wax crystalloids on the adaxial and abaxial sides of young and mature jujube leaves were observed in the two ploidy types,and unique cuticular wax crystalloids covering a large area of the cuticle on autotetraploid sour jujube leaves may provide an advantage in reducing leaf non-stomata transpiration and improving plant drought tolerance.Based on the transcriptome,115 differentially expressed genes between diploids and autotetraploids were further analyzed and found to be involved in the accumulation of cuticular wax components,including terpenoids,fatty acids,and lipids,as well as ABC transporter and wax biosynthetic process.Finally,14 genes differentially expressed between glossy autotetraploid leaves and nonglossy diploid leaves,such as LOC107414787,LOC107411574 and LOC107413721,were screened as candidate genes by qRT-PCR analysis.This findings provided insights into how polyploidization improved drought tolerance.
基金Financial support by project of China Petroleum Engineering Corp., Ltd (CPEC), Study on microstructural regulation of polyacrylate and applying as pour-point depressant for crude oil (2021ZYGC-01-01)。
文摘The gelation of crude oil with high wax and asphaltene content at low temperatures often results in the block of transportation pipeline in Africa. In recent years, it was reported that surface hydrophobicmodified nanoparticles have important applications in crude oil flow modification. In this work, four kinds of core-shell hybride nanoparticles by grafting poly(octadecyl, docosyl acrylate) and poly(acrylate-α-olefin) onto the surface of nano-sized SiO_(2) were synthesized by grafting polymerization method.The chemical structure of nanoparticles was analyzed by Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM) and thermogravimetric analysis(TGA). The rheological behaviors of crude oil and precipitation of asphaltenes in the presence of nanoparticles were studied by measuring the viscose-temperature relationship curve, the cumulative wax precipitation amount, and morphology of waxes and asphaltenes. The results indicate that the docosyl polyacrylate@SiO_(2) nanoparticle(PDA@SiO_(2)) can reduce the cumulative wax precipitation amount of crude oil by 72.8%, decline the viscosity of crude oil by 85.6% at 20℃, reduce the average size of wax crystals by 89.7%, and inhibit the agglomeration of asphaltene by 74.8%. Therefore, the nanoparticles not only adjust the crystalline behaviors of waxes, but also inhibit the agglomeration of asphaltenes. Apparently, core-shell hybride nanoparticles provides more heterogeneous nucleation sites for the crystallization of wax molecules,thus inhibiting the formation of three-dimensional network structure. The core-shell polymer@SiO_(2) hybride nanoparticles are one of promising additives for inhibiting crystallization of waxes and agglomeration of asphaltenes in crude oil.
基金financial support received from National Natural Science Foundation of China(22178378 and 22127812)"Tianchi Talent"Recruitment Program,Xinjiang Tianshan Innovation Team(2022TSYCTD0002)Xinjiang Uygur Region"One Case,One Policy"Strategic Talent Introduction Project(XQZX20240054)are gratefully acknowledged.
文摘Ethylene-vinyl acetate copolymer(EVA) as a kind of effective polymeric pour point depressant has been extensively used in the pipeline transportation of crude oil to inhibit wax deposition and improve the low temperature fluidity of crude oil. In this work, molecular dynamics simulations were performed to investigate the effect of EVA on wax-hydrate coexistence system to evaluate the application potentiality of EVA to the flow assurance of deep-sea oil-gas-water multiphase flow system. Our simulation results reveal that wax molecules gradually stretched and stacked from random coiling to a directional and ordered crystalline state during the process of wax solidification. The strong affinity of polar vinyl acetate side chains of EVA to neighboring water molecules made the EVA molecule prefer being in a curly state,which disrupted the ordered crystallization of surrounding wax molecules and delayed the solidification rate of wax cluster. In addition, it is found that EVA cocrystallized with wax molecules to form eutectic when the wax was fully solidified. The simulation results of hydrate nucleation and growth show that the EVA molecule displayed a two-sided effect on gas adsorption of wax crystals, which was the key factor that affected the nucleation and growth of hydrates in the methane-water system. The nonpolar hydrocarbon backbone of EVA increased the diffusion rate of methane and water, allowing more methane to diffuse to the surface of wax crystals, reducing the methane concentration in aqueous solutions and inhibiting the hydrate formation. On the other hand, the nonpolar vinyl acetate chains had a repulsive effect on methane, which reduced the adsorption area of methane on the eutectic surface and decreased the adsorption threshold value of the wax crystal. The excluded methane molecules would continue dissociating in the aqueous phase and participating in the nucleation and growth process of hydrates.Therefore, the probability of hydrate formation would be increased. It was worth noting that the inhibition performance of EVA on hydrate formation mainly played a significant role in the system with small wax crystal, while its hydrate promotion effect played a dominant role in the system with lager wax crystal. In summary, EVA could significantly inhibit both of the wax and hydrate deposition for the waxgas-water multiphase system with low wax content. When the wax content in the system was high, the role of EVA was mainly played in the alleviation of wax crystallization rather than the gas hydrates. The results of the present work can contribute to a better understanding of EVA on wax deposition and hydrate formation, and provide theoretical support of the potential industrial applications of EVA.
文摘The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffin wax was modified through four types of modifiers,including organic high-molecular-mass resins,plasticizers,surfactants and lubricants.The qualitative screening of resin types was explored and an orthogonal experiment involving the combination of these four paraffin wax modifiers was conducted to obtain an optimized quantitative ratio of modifiers.The results reveal that the insertion of the small molecule chain of resin into the interstitial spaces of paraffin wax crystals is likely a crucial factor for improving the compatibility between the resin and paraffin wax.Through orthogonal experiments,the optimized formulation for the forming agent is determined:100 parts of 58#paraffin wax,15 parts of EVA-2,4 parts of DPHP,4 parts of oleic acid amide and 2 parts of stearic acid.This optimized formulation is applied to industrial production at one Chinese company,and qualified deep well-shaped cemented carbide products are achieved,which contain 90wt%WC and 10wt%Co.
基金the financial support from Scientific Research Program of Beijing Municipal Commission of Education(KM202110017009,granted to Xiaoyan Guo)Undergraduates Research Training Program of Beijing Institute of Petrochemical Technology(2022J00178,granted to Lizhu Li)。
文摘Microbial enhanced oil recovery(MEOR)is a cost effective and efficient method for recovering residual oil.However,the presence of wax(paraffin)in residual oil can substantially reduce the efficiency of MEOR.Therefore,microbial dewaxing is a critical process in MEOR.In this study,a bacterial dewaxing agent of three spore-forming bacteria was developed.Among these bacteria,Bacillus subtilis GZ6 produced the biosurfactant surfactin.Replacing the promoter of the surfactin synthase gene cluster(srfA),increased the titer of surfactin in this strain from 0.33 g/L to 2.32 g/L.The genetically modified strain produced oil spreading rings with diameters increasing from 3.5±0.1 to 4.1±0.2 cm.The LadA F10L/N133R mutant was created by engineering an alkane monooxygenase(LadA)using site-directed mutagenesis in the Escherichia coli host.Compared to the wild-type enzyme,the resulting mutant exhibited an 11.7-fold increase in catalytic efficiency toward the substrate octadecane.When the mutant(pIMPpladA2mu)was expressed in Geobacillus stearothermophilus GZ178 cells,it exhibited a 2.0-fold increase in octadecane-degrading activity.Cultures of the two modified strains(B.subtilis GZ6(pg3srfA)and G.stearothermophilus GZ178(pIMPpladA2mu))were mixed with the culture of Geobacillus thermodenitrificans GZ156 at a ratio of 5:80:15.The resulting composition increased the rate of wax removal by 35%compared to the composition composed of three native strains.This study successfully developed a multi-strain bacterial agent with enhanced oil wax removal capabilities by genetically engineering two bacterial strains.
文摘The phenomenon of petroleum wax deposition is very common during oil well production. When the wax molecule condenses on the surface of the pipeline, it will hinder the exploitation of crude oil, reduce the recovery rate of crude oil, and may lead to the blockage of the pipeline when it is serious, so that the oil recovery work will stop. This phenomenon can be obviously changed by using wax cleaning agent. However, the low ignition point and toxicity of oil-based wax remover are not conducive to oil recovery. Therefore, a new water-based paraffin remover SGJ-1 was developed in this paper. The best formula is: wax dispersant 15%, wetting reversion agent 1%, sodium silicate 1%, alcohol cosolvent 8% and 75% water. Condensation point, wax dissolution rate and anti-wax performance of SGJ-1 water-based dewaxing and anti-waxing agent were tested by self-assembly testing device. The experimental results show that the condensation point of SGJ-1 is -34°C, the viscosity reduction effect is good under 35°C, and the wax dissolution rate is 0.0512 g/min, The highest wax prevention rate can reach 89.58% and the wax removal and wax prevention ability is excellent. Compared with other paraffin removers, SGJ-1 can also reduce the viscosity of crude oil, so it has a good development prospect.
基金UCSI Universitythe Universiti Malaysia Pahang for their continuous support
文摘The present study investigated the wax deposition tendencies of a light Malaysian crude oil（42.4° API）, and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant（highest） and bio-surfactant（lowest）revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO2 nanoparticle suspension in a load ratio of 3：1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate.
文摘Wax deposits on the wall of a crude oil pipeline are a solid wax network of fine crystals, filled with oil, resin, asphaltene and other impurities. In this paper, a series of experiments on wax deposition in a laboratory flow loop were performed under different conditions （flow rate, temperature differential between crude oil and pipeline wall, and dissolved wax concentration gradient）, and the wax deposits were analyzed, so quantitative relationships among wax content, wax appearance temperature （WAT）, shear stress, and radial concentration gradient of dissolved wax at the solid/liquid interface were obtained. Finally, a model was established to predict WAT and the wax content of the deposit.
