The Experts below are selected from a list of 5820 Experts worldwide ranked by ideXlab platform
Nitu Sood - One of the best experts on this subject based on the ideXlab platform.
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isolation and characterization of a potential paraffin wax degrading thermophilic bacterial strain geobacillus kaustophilus teri nsm for application in oil wells with paraffin deposition problems
Chemosphere, 2008Co-Authors: Nitu SoodAbstract:Abstract Paraffin deposition problems, that have plagued the oil industry, are currently remediated by mechanical and chemical means. However, since these methods are problematic, a microbiological approach has been considered. The bacteria, required for the mitigation of paraffin deposition problems, should be able to survive the high temperatures of oil wells and degrade the Paraffins under low oxygen and nutrient conditions while sparing the low carbon chain Paraffins. In this study, a thermophilic paraffinic wax degrading bacterial strain was isolated from a soil sample contaminated with paraffinic crude oil. The selected strain, Geobacillus TERI NSM , could degrade 600 mg of paraffinic wax as the sole carbon source in 1000 ml minimal salts medium in 7 d at 55 °C. This strain was identified as Geobacillus kaustophilus by fatty acid methyl esters analysis and 16S rRNA full gene sequencing. G. kaustophilus TERI NSM showed 97% degradation of eicosane, 85% degradation of pentacosane and 77% degradation of triacontane in 10 d when used as the carbon source. The strain TERI NSM could also degrade the Paraffins of crude oil collected from oil wells that had a history of paraffin deposition problems.
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isolation and characterization of a potential paraffin wax degrading thermophilic bacterial strain geobacillus kaustophilus teri nsm for application in oil wells with paraffin deposition problems
Chemosphere, 2008Co-Authors: Nitu Sood, Banwari LalAbstract:Paraffin deposition problems, that have plagued the oil industry, are currently remediated by mechanical and chemical means. However, since these methods are problematic, a microbiological approach has been considered. The bacteria, required for the mitigation of paraffin deposition problems, should be able to survive the high temperatures of oil wells and degrade the Paraffins under low oxygen and nutrient conditions while sparing the low carbon chain Paraffins. In this study, a thermophilic paraffinic wax degrading bacterial strain was isolated from a soil sample contaminated with paraffinic crude oil. The selected strain, Geobacillus TERI NSM, could degrade 600mg of paraffinic wax as the sole carbon source in 1000ml minimal salts medium in 7d at 55 degrees C. This strain was identified as Geobacillus kaustophilus by fatty acid methyl esters analysis and 16S rRNA full gene sequencing. G. kaustophilus TERI NSM showed 97% degradation of eicosane, 85% degradation of pentacosane and 77% degradation of triacontane in 10d when used as the carbon source. The strain TERI NSM could also degrade the Paraffins of crude oil collected from oil wells that had a history of paraffin deposition problems.
Banwari Lal - One of the best experts on this subject based on the ideXlab platform.
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isolation and characterization of a potential paraffin wax degrading thermophilic bacterial strain geobacillus kaustophilus teri nsm for application in oil wells with paraffin deposition problems
Chemosphere, 2008Co-Authors: Nitu Sood, Banwari LalAbstract:Paraffin deposition problems, that have plagued the oil industry, are currently remediated by mechanical and chemical means. However, since these methods are problematic, a microbiological approach has been considered. The bacteria, required for the mitigation of paraffin deposition problems, should be able to survive the high temperatures of oil wells and degrade the Paraffins under low oxygen and nutrient conditions while sparing the low carbon chain Paraffins. In this study, a thermophilic paraffinic wax degrading bacterial strain was isolated from a soil sample contaminated with paraffinic crude oil. The selected strain, Geobacillus TERI NSM, could degrade 600mg of paraffinic wax as the sole carbon source in 1000ml minimal salts medium in 7d at 55 degrees C. This strain was identified as Geobacillus kaustophilus by fatty acid methyl esters analysis and 16S rRNA full gene sequencing. G. kaustophilus TERI NSM showed 97% degradation of eicosane, 85% degradation of pentacosane and 77% degradation of triacontane in 10d when used as the carbon source. The strain TERI NSM could also degrade the Paraffins of crude oil collected from oil wells that had a history of paraffin deposition problems.
Li Li - One of the best experts on this subject based on the ideXlab platform.
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effect of polar nonpolar groups in comb type copolymers on cold flowability and paraffin crystallization of waxy oils
Fuel, 2013Co-Authors: Jun Xu, Shili Xing, Huiqin Qian, Rui Zhang, Sheng Chen, Li LiAbstract:Abstract Comb-type poly(maleic alkylamide-co-α-octadecene) copolymers (MACs) with various ratios of polar carboxyl group/nonpolar octadecyl group were synthesized. Upon cooling, MACs change the size and shape of paraffin crystals, and reduce the pour point and yield stress of waxy oils, as observed by rheology, polarizing light microscopy, differential scanning calorimetry, and X-ray diffraction. They also reduce the paraffin crystallization temperature and enthalpies, inhibit the formation of layer structure of paraffin crystals. Their efficiency to improve the cold flowability was found to correlate to the ratio of polar/nonpolar group (r). MAC with r of 0.4, is more effective than the other two in improving the flowability of waxy oils. It seems that MAC2 can balance the competitive assembly behaviors of copolymers with Paraffins and asphaltenes. The assembly between the carboxyl and amide groups of MACs with polar aromatic asphaltenes appears to stabilize crude oil by the steric effects of the long-chain alkyl branches of MAC polymers, thereby improving the flowability of paraffin/asphaltene gels formed upon cooling.
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improvement of oil flowability by assembly of comb type copolymers with paraffin and asphaltene
Aiche Journal, 2012Co-Authors: Li Li, Jack Tinsley, Douglas H Adamson, J. S. Huang, Brian Anthony Pethica, Jun Xu, Robert K PrudhommeAbstract:Comb-type (maleic acid alkylamides-co-α-octadecene) copolymers (MACs) assemble with long-chain n-Paraffins and asphaltenes by the hydrophobic alkyl branches and polar groups, respectively, and improve flowability of crude oils upon cooling. Their effects on the crystallization of Paraffins from model oils were studied by rheology, optical microscopy, differential scanning calorimetry, and X-ray diffraction. Upon cooling, MACs change the size and shape of paraffin crystals and reduce the yield stresses of gels generated by precipitated solids. Deposition of wax was significantly suppressed by MAC as observed using a laboratory-scale deposition apparatus. MACs are more effective than poly(ethylene-butene) copolymers in improving the flowability of crude oils containing asphaltenes. The interactions between the carboxyl and amide groups of MAC with the polar aromatic asphaltenes appear to stabilize crudes through the steric effects of the long alkyl groups of MAC polymers, thereby reducing the strength of paraffin/asphaltene gels formed on cooling. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Minghui Zheng - One of the best experts on this subject based on the ideXlab platform.
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spatial distributions and homolog profiles of chlorinated nonane Paraffins and short and medium chain chlorinated Paraffins in soils from yunnan china
Chemosphere, 2020Co-Authors: Kunran Wang, Lirong Gao, Lin Qiao, Lili Cui, Shuai Zhu, Di Huang, Minghui ZhengAbstract:Abstract To preliminarily investigate the occurrence, spatial distributions, homolog compositions, and ecological risks of chlorinated Paraffins (CPs) in Yunnan, China, 110 soil samples were collected from an area part of Yunnan, representative of the whole Yunnan area, where had similar characteristics to most parts of Yunnan and 22 pooled soil samples were analyzed for 50 CP congener groups (C9–17Cl5–10). The chlorinated nonane paraffin (C9-CP), short chain (SCCP), and medium chain chlorinated paraffin (MCCP) concentrations in soil samples were 8–109 ng/g (average 39 ng/g), 79–948 ng/g (average 348 ng/g), and 20–1206 ng/g (average 229 ng/g), respectively. The C9-CP homologs contributed 5%–16% of the C9–13-CP concentrations in soils. No significant correlation was found between CP concentrations and the total organic carbon content (P > 0.05). The CP levels in soils from Yunnan were at a medium level compared with those in other areas worldwide. Human activity and atmosphere deposition would influence the levels and spatial distributions of CPs in this area. The concentrations of CPs in east area were higher than those in west area. C10Cl6–7 were the major SCCP congeners and C14Cl6–7 were the major MCCP congeners. Principal component analysis indicated that SCCPs and MCCPs came from different sources. A preliminary risk assessment indicated that these concentrations of CPs in soil from Yunnan do not pose a significant ecological risk for soil organisms.
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characterization of short and medium chain chlorinated Paraffins in cereals and legumes from 19 chinese provinces
Chemosphere, 2019Co-Authors: Runhua Wang, Lirong Gao, Minghui Zheng, Lei Zhang, Guoquan Wang, Lipei Xiong, Danting Ding, Lin Qiao, Lili CuiAbstract:Abstract Short-chain chlorinated Paraffins (SCCPs) were added to the Stockholm Convention Annex A in May 2017. China is the largest producer of chlorinated Paraffins (CPs). CPs in the environment can be transferred to foodstuffs directly and through bioaccumulation and then ingested by humans. Cereals and legumes are important components of Chinese diets, so the risks posed by CPs in cereals and legumes should be of concern. 1710 cereal samples and 1710 legume samples from 19 Chinese provinces were pooled by type and province (giving 19 pooled cereal and 19 pooled legume samples). The SCCP and medium-chain chlorinated paraffin (MCCP) concentrations in the samples were determined by comprehensive two-dimensional gas chromatography tandem time-of-flight mass spectrometry (GC × GC-TOFMS). The mean SCCP concentrations in the cereal and legume samples were 343 and 328 ng g−1 wet weight (ww), respectively, and the mean MCCP concentrations were 213 and 184 ng g−1 ww, respectively. The dominant SCCP congener groups were C10Cl6–7 in cereals and C10Cl5–6 in legumes. The MCCP congener groups C14Cl6–7 were dominant in both cereals and legumes. The CP concentrations were higher in samples from eastern China than in samples from other regions. Risk assessments indicated that SCCPs and MCCPs in cereals and legumes do not pose strong risks to Chinese residents.
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dietary exposure to short and medium chain chlorinated Paraffins in meat and meat products from 20 provinces of china
Environmental Pollution, 2018Co-Authors: Huiting Huang, Runhua Wang, Lirong Gao, Minghui Zheng, Lei Zhang, Lin Qiao, Lili Cui, Dan Xia, Wenbin LiuAbstract:Food intake is one of the main pathways of human exposure to chlorinated Paraffins (CPs). This study assessed the dietary exposure for the general Chinese population to short-chain chlorinated paraffin (SCCPs) and medium-chain chlorinated Paraffins (MCCPs) through meat and meat products. Twenty samples of meat and meat products from 20 Chinese provinces were collected in 2011. As the sampling sites covered about two-thirds of the Chinese population, the meat samples were considered to be representative of the true characteristics of CPs contamination in Chinese meat products. The concentrations of SCCPs and MCCPs in the meat samples were measured using the comprehensive two-dimensional gas chromatography electron capture negative ionization high-resolution time-of-flight mass spectrometry method. Forty-eight SCCP and MCCP homolog groups were detected in the meat samples. The mean SCCP and MCCP concentrations in all meat samples were 129 ± 4.1 ng g-1 wet weight and 5.7 ± 0.59 ng g-1 wet weight, respectively. The concentrations of SCCPs and MCCPs varied in samples from different provinces. The geographical distribution of CP concentrations was similar to the distribution of CPs manufacturing plants in China. The most abundant groups of SCCPs in all samples were C10-11 Cl6-7, and the most abundant groups of MCCPs in most samples were C14 Cl7-8. The possible sources of SCCPs and MCCPs in meat and meat products might be CP-42 and CP-52. The 50th percentile estimated daily intakes of SCCPs and MCCPs through meat consumption for a "standard" Chinese adult male were 0.13 and 0.0047 μg kg-1 bw d-1, respectively, both much lower than the tolerable daily intakes (TDIs) for SCCPs and MCCPs. This preliminary risk assessment has indicated that the indirect exposure of SCCPs and MCCPs through meat consumption does not pose significant risk to human health in China.
Ahmet Sari - One of the best experts on this subject based on the ideXlab platform.
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form stable paraffin high density polyethylene composites as solid liquid phase change material for thermal energy storage preparation and thermal properties
Energy Conversion and Management, 2004Co-Authors: Ahmet SariAbstract:Abstract This paper deals with the preparation of paraffin/high density polyethylene (HDPE) composites as form-stable, solid–liquid phase change material (PCM) for thermal energy storage and with determination of their thermal properties. In such a composite, the paraffin (P) serves as a latent heat storage material and the HDPE acts as a supporting material, which prevents leakage of the melted paraffin because of providing structural strength. Therefore, it is named form-stable composite PCM. In this study, two kinds of Paraffins with melting temperatures of 42–44 °C (type P1) and 56–58 °C (type P2) and latent heats of 192.8 and 212.4 J g −1 were used. The maximum weight percentage for both paraffin types in the PCM composites without any seepage of the paraffin in the melted state were found as high as 77%. It is observed that the paraffin is dispersed into the network of the solid HDPE by investigation of the structure of the composite PCMs using a scanning electronic microscope (SEM). The melting temperatures and latent heats of the form-stable P1/HDPE and P2/HDPE composite PCMs were determined as 37.8 and 55.7 °C, and 147.6 and 162.2 J g −1 , respectively, by the technique of differential scanning calorimetry (DSC). Furthermore, to improve the thermal conductivity of the form-stable P/HDPE composite PCMs, expanded and exfoliated graphite (EG) by heat treatment was added to the samples in the ratio of 3 wt.%. Thereby, the thermal conductivity was increased about 14% for the form-stable P1/HDPE and about 24% for the P2/HDPE composite PCMs. Based on the results, it is concluded that the prepared form-stable P/HDPE blends as composite type PCM have great potential for thermal energy storage applications in terms of their satisfactory thermal properties and improved thermal conductivity. Furthermore, these composite PCMs added with EG can be considered cost effective latent heat storage materials since they do not require encapsulation and extra cost to enhance heat transfer in the paraffin.
