In order to realize tobacco curing with energy saving and emission reduc- ing and lower cost, the waste heat recovering equipment was designed and built on blowing-upward type bulk curing barn. The comparative experim...In order to realize tobacco curing with energy saving and emission reduc- ing and lower cost, the waste heat recovering equipment was designed and built on blowing-upward type bulk curing barn. The comparative experiment of tobacco leaf curing was conducted between a bulk curing barn with waste heat of flue gas and conventional bulk curing barn. The results showed that the effect of saving coal in bulk curing barn with waste heat of flue gas was obvious than the contrast. The coal consumption quantity was 1.531 kg per kg of dry tobacco leaf. The saving coal in bulk curing barn with use waste heat of flue gas was 0.181 kg per kg of dry tobacco leaf than the contrast and saving coal rate was 10.57%. The electricity consumption quantity was 0.593 kWh per kg of dry tobacco leaf. The saving elec- tricity quantity in bulk curing barn with use waste heat of flue gas was 0.022 kWh/kg and the saving electricity rate was 3.58% than the contrast. The saving curing cost was 0.158 yuan per kg of dry tobacco leaf and saving cost rate 9.09% in bulk cur- ing barn with use waste heat of flue gas than the contrast. The appearance quality, grade structure and primary chemical composition had no significant difference be- tween bulk curing barn with use waste heat of flue gas and the contrast.展开更多
The present paper describes the implementation of GPR 3D survey for detecting and delineating possible remain<span style="font-family:"">s</span><span style="font-family:""...The present paper describes the implementation of GPR 3D survey for detecting and delineating possible remain<span style="font-family:"">s</span><span style="font-family:""> of hydrocarbon plumes on a gas station. The 3D-imaging was used for the detection of anomalous zones that were analyzed with some relevant signal attributes extracted by digital signal processing. These signal attributes or parameters ha</span><span style="font-family:"">ve</span><span style="font-family:""> been the frequency of the maximum energy concentration on time-frequency distribution and instantaneous amplitude that could be related </span><span style="font-family:"">to</span><span style="font-family:""> the local response of the electromagnetic interaction and the presence of hydrocarbon plumes or soil contaminated area</span><span style="font-family:"">s</span><span style="font-family:"">. The implementation methodology took place at a gas station monitored with a piezometric sensor installation with soil layer information. The 3D-imaging of processed data and its slicing tool permits visualizing expected targets as pipes, tanks and installations in the subsoil exposing the anomalous zones for refined analyses. This further processing has used some spectral attributes of the signal to assess the real presence of the total petroleum hydrocarbons (TPH) providing a new effort to simplify and overcome the current state of the geophysical methods able to assess the presence of hydrocarbon plumes </span><span style="font-family:"">in</span><span style="font-family:""> industrial environments regarding the time cost of the survey and the traceable indication of the spectral shi</span><span style="font-family:"">ft</span><span style="font-family:"">ment shown in the plume volume.</span>展开更多
Shanghai Power Station Auxiliary Equipment Works (referred to as SDF) was established in April, 1980 on the base of the urban area previously owned by Shanghai Boiler Works so as to facilitate
To achieve excellent production capability and maintain high security for nuclear power stations, equipment reliability is studied as a key issue. As the main branch, equipment reliability management is considered as ...To achieve excellent production capability and maintain high security for nuclear power stations, equipment reliability is studied as a key issue. As the main branch, equipment reliability management is considered as an effective approach to make plant management strategy and organize routine work. Some achievements on research and application of equipment reliability management at Daya Bay Nuclear Power Station are introduced in this paper. By studying and implementing 1NPO (Institute of Nuclear Power Operations) AP-913 equipment reliability process, reliability-centered maintenance (RCM), critical component management (CCM), and many other similar methods, equipment reliability management system has been established at Daya Bay. And by continuous effort on improving application effect of these technologies, some innovation has also been made. Some innovative products, such as iSOM Intelligent Expert System, reliability and technique centered maintenance (RtCM), predictive maintenance system (PdM), and so on, have been developed. Based on these achievements, Daya Bay Nuclear Power Station has achieved excellent operation performance and won several prizes in WANO (World Association of Nuclear Operators) competition every year.展开更多
This study aims to find out the relevance of marketing strategies for gas stations in China.According to IBISWorld,the companies holding the largest market shares in China’s gas station industry include China Petroch...This study aims to find out the relevance of marketing strategies for gas stations in China.According to IBISWorld,the companies holding the largest market shares in China’s gas station industry include China Petrochemical Corporation,China National Petroleum Corporation,Sinochem Corporation,China National Offshore Oil Corporation,and BP(China)Holdings Limited.Marketing has changed over the past several years.Similarly,gas station marketing is all about more customers,greater sales,and higher profits.Technology provides many different marketing tools to see more fresh faces at the door,increase repeat sales,and improve profits.Word-of-mouth advertising should be encouraged,especially when contests are being held.The prizes from these contests may include car essentials,free coffee,free car wash,or coupons to be used at convenience stores.Customers who have won these contests would surely go around advertising the particular gas station,ultimately bringing in more customers.Other than that,managers can boost the sales volume through radio promotions as well.This study also aims to give future businessmen and women some ideas on how to deal with different kinds of strategies when it comes to marketing,especially in China in hope to cater and prove to the people of China the possibility of promoting businesses,such as the oil industry.展开更多
The paper provides an insight into key engineering aspects of Kuwait Oil Company's existing projects, facilities and equipment both current and from nearly 30 years of projects development. It deals with engineering ...The paper provides an insight into key engineering aspects of Kuwait Oil Company's existing projects, facilities and equipment both current and from nearly 30 years of projects development. It deals with engineering features of mainly process and mechanical equipment, both static and rotating besides others, used for collection, separation, desalting, heat transfer, chemical treatment, storage, transmission, pipelines and similar facilities utilized for upstream oil and gas production, both sweet and sour. Engineering highlights include certain technological developments, metallurgical aspects, few best practices and lessons learnt as well. Seven (7) case studies are included towards the end that show case some of the engineering aspects of facility equipment, lessons learned from their engineering and conclusions drawn that, emphasize the need to focus on initial, preliminary engineering aspects of projects and could provide useful tips for oil and gas engineers and designers.展开更多
Geological penetrating radar combined with drilling and chemical analysis has been applied to investigate leakage pollution of Longpan Road gas station in Nanjing, China. The results indicate that radar images show st...Geological penetrating radar combined with drilling and chemical analysis has been applied to investigate leakage pollution of Longpan Road gas station in Nanjing, China. The results indicate that radar images show strong reflection anomalies along the northeast to the gas station, characterized by contaminants or contaminant plumes spreading downstream and below. The drilling results confirmed the contents of monocyclic and polycyclic aromatic hydrocarbons contained in the layers of fine sands ranging from 0.60 m to 6.0 m beneath the surface mostly exceed Chinese standard severely, such as toluene and isobutylbenzene with high content at 2738 μg/kg and 64505 μg/kg, respectively. Therefore, it is considered that geological penetrating radar can be employed to investigate leakage contamination of gas stations, and remediation and administration should be conducted in the polluted soil layers and aquifers.展开更多
Gas stations are important emissions source of benzene (C6H6), toluene (C7H8), ethylbenzene (C8H10), and ortho, meta and para-xylene (C8H10)—better known by the acronym BTEX. The objective of this study was to determ...Gas stations are important emissions source of benzene (C6H6), toluene (C7H8), ethylbenzene (C8H10), and ortho, meta and para-xylene (C8H10)—better known by the acronym BTEX. The objective of this study was to determine the concentrations of BTEX compounds in the ambient air of ten gas stations in the cities of Salvador and Feira de Santana, Bahia, Brazil and evaluate the health risks to workers. Passive samplers diffusive of the Radiello?, containing activated carbon as adsorbent, were used. The samplers were exposed for 8 h and then the analytes were recovered by chemical desorption with CS2 and determined by GC-FID. The BTEX concentrations found in the ambient air of gas stations ranged from 46.72 - 435.43 μg·m?3 for benzene;25.54 - 342.46 μg·m?3 for toluene, 7.10 - 30.07 μg·m?3 for ethylbenzene, 9.36 - 89.73 μg·m?3 for m, p-xylene and 9.79 - 52.29 μg·m?3 for o-xylene. The concentrations of toluene, ethylbenzene and xylenes found in gas stations were lower than the limits recommended by the US NIOSH and NR-15 of the Ministry of Labour of Brazil;however, it should be considered the risks due to chronic exposure of workers. Benzene concentrations in three gas stations were above the exposure limit recommended by NIOSH (3.20 × 102 μg·m?3). Samplings were also held outdoors at 250 m of two gas stations. The total concentrations of the BTEX compounds were equal to 24.97 and 35.51 μg·m?3, and benzene concentrations were about 3 - 4 times higher than the annual pattern of 5.0 μg·m?3 established by Union European, as tolerance limit for outside areas. These data confirm that the next areas of gas stations are subject to the effects of volatilization of these compounds. Additionally, the values found in the 10 gas stations for the cancer risk ranged from 4.06 × 10?5 - 3.78 × 10?4 (mean of 1.82 × 10?4) for workers exposed to benzene for 30 years (acceptable limit equal 1.00 × 10?6). The cancer risk is very high, because the values found are about 40 - 378 times above the acceptable limit and reinforce the need to adopt urgent measures to reduce or eliminate exposure of workers to the BTEX compounds. The average non-cancer risk to benzene, toluene, ethylbenzene and xylenes was 1.84, 5.76 × 10?3, 4.59 × 10?3 and 1.37 × 10?1, respectively (acceptable limit 1). Only to benzene the average value of this risk is above 1, showing that workers are likely the adverse effects health due to exposure to benzene.展开更多
To show the risks and harm caused by the occupational exposure to the benzene, toluene, ethylbenzene and xylenes compounds (BTEX), the working conditions of 113 persons employed at gas stations in the cities of Riach?...To show the risks and harm caused by the occupational exposure to the benzene, toluene, ethylbenzene and xylenes compounds (BTEX), the working conditions of 113 persons employed at gas stations in the cities of Riach?o do Jacuipe, Feira de Santana and Salvador in the state of Bahia, Brazil were investigated by experts who correlated protection measures required by law and those applied to the workers. Data collection was performed by help of a questionnaire and non-participant observation record. The age groups of the workers in the three cities surveyed were between 18 to 25 years (30.08%) and 26 to 33 years (34.51%) of the total. The study revealed an association between occupational habits of workers at gas stations and the prevalence of symptoms due to the exposure to the BTEX compounds. Regarding the use of Personal Protective Equipment (PPE) most workers wear boots. The data show that these workers reported symptoms such as headache, rhinitis, leg pain, drowsiness, cough, fatigue, insomnia, tremors and palpitations. These disorders are related back to previous exposure to BTEX compounds which is associated with inadequate occupational habits of the workers which potentiate chemical contamination in their respective environment.展开更多
In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. B...In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. Because of the harsh environment of seafloor,high pressure and highly conductive seawater,marine magnetotelluric method developed slowly. The sea floor environment is similar to the environment of logging, According to the design of dual lateral logging equipment,a new equipment for seafloor electrical resistivity measurement is designed. Four 3D FEM models that contain resistivity abnormal targets are built to test the ability of this equipment to locate different shape of shallow buried resistivity abnormal targets in sea mud. The authors propose the method to correct the response curve while the bottom surface of this equipment is suspended or not parallel to the seafloor. The resistivity of targets can be calculated accurately.展开更多
Gas-insulated equipment(GIE)that utilizes the most potent greenhouse gas sulfur hexafluoride(SF_(6))as insulation and arc-quenching medium has been widely used in the power industry.Seeking eco-friendly insulating gas...Gas-insulated equipment(GIE)that utilizes the most potent greenhouse gas sulfur hexafluoride(SF_(6))as insulation and arc-quenching medium has been widely used in the power industry.Seeking eco-friendly insulating gas with advanced performance for next-generation SF_(6)-free GIE is significant for the“net-zero”goal and sustainable development.In this paper,the utilization,emission,and reduction policies of SF_(6)around the world were summarized first.Then,we systematically reviewed the latest progress in comprehensive performance evaluation of eco-friendly insulating gas in terms of molecular design,dielectric insulation,arc-quenching,stability and decomposition,materials compatibility,biosafety,etc.Further,the representative applications of eco-friendly insulating gas in medium-voltage,high-voltage GIE as well as relevant maintenance-related technologies were highlighted.Accordingly,the existing challenges and future perspectives were proposed,presenting a roadmap to hopefully steer the development of eco-friendly insulating gas and GIE.展开更多
1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in leng...1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced concrete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.展开更多
Charge accumulation on the spacer surface in gas insulated equipment is very severe in the DC field,leading to easy flashover,which restricts the application of DC GIS/GIL.Therefore,knowledge about the charge accumula...Charge accumulation on the spacer surface in gas insulated equipment is very severe in the DC field,leading to easy flashover,which restricts the application of DC GIS/GIL.Therefore,knowledge about the charge accumulation characteristics of gas insulated equipment at DC stress is essential.In this paper,we reviewed the research methods and the characteristics of charge accumulation on spacers.A summary of charge measurement methods and setups are presented.And the surface charge inversion algorithms are introduced.Then the simulation model for charge accumulation in the DC field is reviewed.Subsequently,the charge accumulation mechanisms and phenomenon,the influence factor of surface charge accumulation and the influence of accumulated charge on spacer insulation characteristics are summarized.In addition,some suppression methods of surface charge accumulation are discussed.Finally,based on the understanding of charge accumulation on spacers,some suggestions on further studies are presented to aid in the design of a better spacer free from surface charges.展开更多
Regulator station is an important part in the urban gas transmission and distribution system.Once gas explosion occurs,the real explosion process and consequences of methane gas explosion in the regulator station were...Regulator station is an important part in the urban gas transmission and distribution system.Once gas explosion occurs,the real explosion process and consequences of methane gas explosion in the regulator station were not revealed systematically.In this study,a full-scale experiment was carried out to simulate the regulator station explosion process,and some numerical simulations with a commercial CFD software called FLACS were conducted to analyze the effect of ignition and vent conditions on the blast overpressure and flame propagation.The experimental results demonstrated that the peak overpressure increased as the distance from the vent increased within a certain distance.And the maximum overpressure appeared 3 m away from the door,which was about 36.6 kPa.It was found that the pressure-time rising curves obtained from the simulation are basically the same as the ones from the experiment,however,the time of reaching the peak pressure was much shorter.The numerical simulation results show that the peak overpressures show an increase trend as the ignition height decreased and the vent relief pressure increased.It indicates that the damage and peak overpressure of gas explosion could be well predicted by FLACS in different styles of regulator station.In addition,the results help us to understand the internal mechanism and development process of gas explosion better.It also offers technical support for the safety protection of the urban regulator station.展开更多
Natural gas is transported from producing regions to consumption regions by using transmission pipelines at high pressures. At consumption regions, the pressure of natural gas is reduced in city gate stations(CGSs). B...Natural gas is transported from producing regions to consumption regions by using transmission pipelines at high pressures. At consumption regions, the pressure of natural gas is reduced in city gate stations(CGSs). Before the pressure reduction process, the temperature of natural gas is increased usually by using a water bath heater,which burns natural gas as fuel, to protect against freezing of natural gas. These types of heat exchangers have a low efficiency and consume a lot of fuel to generate the required heat. In the current study, the twisted configuration of the heating coil is proposed and investigated to enhance the heat transfer through a water bath heater with a nominal capacity of 1000 m^3·h^-1. Firstly, the implementation procedure is validated with data collected from the CGS of Qaleh-Jiq(located in Golestan province of Iran). A very good agreement is achieved between the obtained results and the real data. Then, three different twist ratios are considered to examine the twisting effects. The proposed technique is evaluated in the terms of velocity, temperature, and pressure variations, and the results are compared with the conventional case, i.e. straight configuration. It is found that both the heat transfer rate and the pressure drop augment as the twist ratio is raised. Finally, it is concluded that the twisted tubes can reduce the length of the gas coil by about 12.5% for the model with low twist ratio, 18.75% for the model with medium twist ratio, and 25% for the model with high twist ratio as compared to the straight configuration.展开更多
Optimal operation of a compressor station is important since it accounts for 25%to 50%of a company’s total operating budget.In short-term management of a compressor station,handling demand uncertainty is important ye...Optimal operation of a compressor station is important since it accounts for 25%to 50%of a company’s total operating budget.In short-term management of a compressor station,handling demand uncertainty is important yet challenging.Previous studies either require precise information about the distribution of uncertain parameters or greatly simplify the compressor model.We build a two-stage robust optimization framework of power cost minimization in a natural gas compressor station with nonidentical compressors.In the first stage,decision variables are the ON/OFF state of each compressor and discharge pressure.The worst-case cost of the second stage is incorporated in the first stage.Firststage decision variables feasibility is discussed and proper feasibility cuts are also proposed for the first stage.We employ a piece-wise approximation and propose accelerate methods.Our numerical results highlight two advantages of robust approach when managing uncertainty in practical settings:(1)the feasibility of first-stage decision can be increased by up to 45%,and(2)the worst-case cost can be reduced by up to 25%compared with stochastic programming models.Furthermore,our numerical experiments show that the designed accelerate algorithm has time improvements of 1518.9%on average(3785.9%at maximum).展开更多
At the China Spallation Neutron Source(CSNS), we have developed a custom gas-filling station, a glassblowing workshop, and a spin-exchange optical pumping(SEOP) system for producing high-quality ^(3)He-based neutron s...At the China Spallation Neutron Source(CSNS), we have developed a custom gas-filling station, a glassblowing workshop, and a spin-exchange optical pumping(SEOP) system for producing high-quality ^(3)He-based neutron spin filter(NSF) cells. The gas-filling station is capable of routinely filling ^(3)He cells made from GE180 glass of various dimensions, to be used as neutron polarizers and analyzers on beamlines at the CSNS. Performance tests on cells fabricated at our gas-filling station are conducted via neutron transmission and nuclear-magneticresonance measurements, revealing nominal filling pressures, and a saturated ~3He polarization in the region of 80%, with a lifetime of approximately 240 hours. These results demonstrate our ability to produce competitive NSF cells to meet the ever-increasing research needs of the polarized neutron research community.展开更多
The design of the pumping stations and the gas injection systems for the inner Chamber and the cryostat on HT-7U superconducting tokamak is described in this paper.
基金Supported by Hebei Industrial Co.,LTD.of China Tobacco(111201315524)Qiannan Co.LTD.Of Guizhou Industrial Co.,LTD.,China Tobacco([2012]17)~~
文摘In order to realize tobacco curing with energy saving and emission reduc- ing and lower cost, the waste heat recovering equipment was designed and built on blowing-upward type bulk curing barn. The comparative experiment of tobacco leaf curing was conducted between a bulk curing barn with waste heat of flue gas and conventional bulk curing barn. The results showed that the effect of saving coal in bulk curing barn with waste heat of flue gas was obvious than the contrast. The coal consumption quantity was 1.531 kg per kg of dry tobacco leaf. The saving coal in bulk curing barn with use waste heat of flue gas was 0.181 kg per kg of dry tobacco leaf than the contrast and saving coal rate was 10.57%. The electricity consumption quantity was 0.593 kWh per kg of dry tobacco leaf. The saving elec- tricity quantity in bulk curing barn with use waste heat of flue gas was 0.022 kWh/kg and the saving electricity rate was 3.58% than the contrast. The saving curing cost was 0.158 yuan per kg of dry tobacco leaf and saving cost rate 9.09% in bulk cur- ing barn with use waste heat of flue gas than the contrast. The appearance quality, grade structure and primary chemical composition had no significant difference be- tween bulk curing barn with use waste heat of flue gas and the contrast.
文摘The present paper describes the implementation of GPR 3D survey for detecting and delineating possible remain<span style="font-family:"">s</span><span style="font-family:""> of hydrocarbon plumes on a gas station. The 3D-imaging was used for the detection of anomalous zones that were analyzed with some relevant signal attributes extracted by digital signal processing. These signal attributes or parameters ha</span><span style="font-family:"">ve</span><span style="font-family:""> been the frequency of the maximum energy concentration on time-frequency distribution and instantaneous amplitude that could be related </span><span style="font-family:"">to</span><span style="font-family:""> the local response of the electromagnetic interaction and the presence of hydrocarbon plumes or soil contaminated area</span><span style="font-family:"">s</span><span style="font-family:"">. The implementation methodology took place at a gas station monitored with a piezometric sensor installation with soil layer information. The 3D-imaging of processed data and its slicing tool permits visualizing expected targets as pipes, tanks and installations in the subsoil exposing the anomalous zones for refined analyses. This further processing has used some spectral attributes of the signal to assess the real presence of the total petroleum hydrocarbons (TPH) providing a new effort to simplify and overcome the current state of the geophysical methods able to assess the presence of hydrocarbon plumes </span><span style="font-family:"">in</span><span style="font-family:""> industrial environments regarding the time cost of the survey and the traceable indication of the spectral shi</span><span style="font-family:"">ft</span><span style="font-family:"">ment shown in the plume volume.</span>
文摘Shanghai Power Station Auxiliary Equipment Works (referred to as SDF) was established in April, 1980 on the base of the urban area previously owned by Shanghai Boiler Works so as to facilitate
文摘To achieve excellent production capability and maintain high security for nuclear power stations, equipment reliability is studied as a key issue. As the main branch, equipment reliability management is considered as an effective approach to make plant management strategy and organize routine work. Some achievements on research and application of equipment reliability management at Daya Bay Nuclear Power Station are introduced in this paper. By studying and implementing 1NPO (Institute of Nuclear Power Operations) AP-913 equipment reliability process, reliability-centered maintenance (RCM), critical component management (CCM), and many other similar methods, equipment reliability management system has been established at Daya Bay. And by continuous effort on improving application effect of these technologies, some innovation has also been made. Some innovative products, such as iSOM Intelligent Expert System, reliability and technique centered maintenance (RtCM), predictive maintenance system (PdM), and so on, have been developed. Based on these achievements, Daya Bay Nuclear Power Station has achieved excellent operation performance and won several prizes in WANO (World Association of Nuclear Operators) competition every year.
文摘This study aims to find out the relevance of marketing strategies for gas stations in China.According to IBISWorld,the companies holding the largest market shares in China’s gas station industry include China Petrochemical Corporation,China National Petroleum Corporation,Sinochem Corporation,China National Offshore Oil Corporation,and BP(China)Holdings Limited.Marketing has changed over the past several years.Similarly,gas station marketing is all about more customers,greater sales,and higher profits.Technology provides many different marketing tools to see more fresh faces at the door,increase repeat sales,and improve profits.Word-of-mouth advertising should be encouraged,especially when contests are being held.The prizes from these contests may include car essentials,free coffee,free car wash,or coupons to be used at convenience stores.Customers who have won these contests would surely go around advertising the particular gas station,ultimately bringing in more customers.Other than that,managers can boost the sales volume through radio promotions as well.This study also aims to give future businessmen and women some ideas on how to deal with different kinds of strategies when it comes to marketing,especially in China in hope to cater and prove to the people of China the possibility of promoting businesses,such as the oil industry.
文摘The paper provides an insight into key engineering aspects of Kuwait Oil Company's existing projects, facilities and equipment both current and from nearly 30 years of projects development. It deals with engineering features of mainly process and mechanical equipment, both static and rotating besides others, used for collection, separation, desalting, heat transfer, chemical treatment, storage, transmission, pipelines and similar facilities utilized for upstream oil and gas production, both sweet and sour. Engineering highlights include certain technological developments, metallurgical aspects, few best practices and lessons learnt as well. Seven (7) case studies are included towards the end that show case some of the engineering aspects of facility equipment, lessons learned from their engineering and conclusions drawn that, emphasize the need to focus on initial, preliminary engineering aspects of projects and could provide useful tips for oil and gas engineers and designers.
文摘Geological penetrating radar combined with drilling and chemical analysis has been applied to investigate leakage pollution of Longpan Road gas station in Nanjing, China. The results indicate that radar images show strong reflection anomalies along the northeast to the gas station, characterized by contaminants or contaminant plumes spreading downstream and below. The drilling results confirmed the contents of monocyclic and polycyclic aromatic hydrocarbons contained in the layers of fine sands ranging from 0.60 m to 6.0 m beneath the surface mostly exceed Chinese standard severely, such as toluene and isobutylbenzene with high content at 2738 μg/kg and 64505 μg/kg, respectively. Therefore, it is considered that geological penetrating radar can be employed to investigate leakage contamination of gas stations, and remediation and administration should be conducted in the polluted soil layers and aquifers.
文摘Gas stations are important emissions source of benzene (C6H6), toluene (C7H8), ethylbenzene (C8H10), and ortho, meta and para-xylene (C8H10)—better known by the acronym BTEX. The objective of this study was to determine the concentrations of BTEX compounds in the ambient air of ten gas stations in the cities of Salvador and Feira de Santana, Bahia, Brazil and evaluate the health risks to workers. Passive samplers diffusive of the Radiello?, containing activated carbon as adsorbent, were used. The samplers were exposed for 8 h and then the analytes were recovered by chemical desorption with CS2 and determined by GC-FID. The BTEX concentrations found in the ambient air of gas stations ranged from 46.72 - 435.43 μg·m?3 for benzene;25.54 - 342.46 μg·m?3 for toluene, 7.10 - 30.07 μg·m?3 for ethylbenzene, 9.36 - 89.73 μg·m?3 for m, p-xylene and 9.79 - 52.29 μg·m?3 for o-xylene. The concentrations of toluene, ethylbenzene and xylenes found in gas stations were lower than the limits recommended by the US NIOSH and NR-15 of the Ministry of Labour of Brazil;however, it should be considered the risks due to chronic exposure of workers. Benzene concentrations in three gas stations were above the exposure limit recommended by NIOSH (3.20 × 102 μg·m?3). Samplings were also held outdoors at 250 m of two gas stations. The total concentrations of the BTEX compounds were equal to 24.97 and 35.51 μg·m?3, and benzene concentrations were about 3 - 4 times higher than the annual pattern of 5.0 μg·m?3 established by Union European, as tolerance limit for outside areas. These data confirm that the next areas of gas stations are subject to the effects of volatilization of these compounds. Additionally, the values found in the 10 gas stations for the cancer risk ranged from 4.06 × 10?5 - 3.78 × 10?4 (mean of 1.82 × 10?4) for workers exposed to benzene for 30 years (acceptable limit equal 1.00 × 10?6). The cancer risk is very high, because the values found are about 40 - 378 times above the acceptable limit and reinforce the need to adopt urgent measures to reduce or eliminate exposure of workers to the BTEX compounds. The average non-cancer risk to benzene, toluene, ethylbenzene and xylenes was 1.84, 5.76 × 10?3, 4.59 × 10?3 and 1.37 × 10?1, respectively (acceptable limit 1). Only to benzene the average value of this risk is above 1, showing that workers are likely the adverse effects health due to exposure to benzene.
文摘To show the risks and harm caused by the occupational exposure to the benzene, toluene, ethylbenzene and xylenes compounds (BTEX), the working conditions of 113 persons employed at gas stations in the cities of Riach?o do Jacuipe, Feira de Santana and Salvador in the state of Bahia, Brazil were investigated by experts who correlated protection measures required by law and those applied to the workers. Data collection was performed by help of a questionnaire and non-participant observation record. The age groups of the workers in the three cities surveyed were between 18 to 25 years (30.08%) and 26 to 33 years (34.51%) of the total. The study revealed an association between occupational habits of workers at gas stations and the prevalence of symptoms due to the exposure to the BTEX compounds. Regarding the use of Personal Protective Equipment (PPE) most workers wear boots. The data show that these workers reported symptoms such as headache, rhinitis, leg pain, drowsiness, cough, fatigue, insomnia, tremors and palpitations. These disorders are related back to previous exposure to BTEX compounds which is associated with inadequate occupational habits of the workers which potentiate chemical contamination in their respective environment.
文摘In order to explore the mineral resources buried in sea mud,it is necessary to use seabed resistivity measuring equipment,which works closer to the sediments than ordinary ship-based geophysical measuring equipment. Because of the harsh environment of seafloor,high pressure and highly conductive seawater,marine magnetotelluric method developed slowly. The sea floor environment is similar to the environment of logging, According to the design of dual lateral logging equipment,a new equipment for seafloor electrical resistivity measurement is designed. Four 3D FEM models that contain resistivity abnormal targets are built to test the ability of this equipment to locate different shape of shallow buried resistivity abnormal targets in sea mud. The authors propose the method to correct the response curve while the bottom surface of this equipment is suspended or not parallel to the seafloor. The resistivity of targets can be calculated accurately.
基金supported in part by the National Natural Science Foundation of China(Nos.52277144,52107145,and 51907023)the fellowship of China Postdoctoral Science Foundation(No.2022M712446).
文摘Gas-insulated equipment(GIE)that utilizes the most potent greenhouse gas sulfur hexafluoride(SF_(6))as insulation and arc-quenching medium has been widely used in the power industry.Seeking eco-friendly insulating gas with advanced performance for next-generation SF_(6)-free GIE is significant for the“net-zero”goal and sustainable development.In this paper,the utilization,emission,and reduction policies of SF_(6)around the world were summarized first.Then,we systematically reviewed the latest progress in comprehensive performance evaluation of eco-friendly insulating gas in terms of molecular design,dielectric insulation,arc-quenching,stability and decomposition,materials compatibility,biosafety,etc.Further,the representative applications of eco-friendly insulating gas in medium-voltage,high-voltage GIE as well as relevant maintenance-related technologies were highlighted.Accordingly,the existing challenges and future perspectives were proposed,presenting a roadmap to hopefully steer the development of eco-friendly insulating gas and GIE.
基金This engineering is a demonstration project for Key Research and Development Project of Guangdong Province under Grant No.2019B111105001part of research related to this engineering was financially supported by the project.
文摘1 Project overview The Shasan station of Phase II of Shenzhen’s urban rail transit Line 12 is situated in Bao’an District,Shenzhen.It comprises a two-level underground island platform station,measuring 212 m in length,and 22.6 m in width,with an overburden thickness of about 7.0 m.Fig.1 illustrates the presence of a large underground reinforced concrete stormwater culvert,measuring 11.5 m by 3.6 m,traversing the station’s center.
基金This work was supported in part by the National Basic Research Program of China(973 Program)(2014CB239500)Young Elite Scientists Sponsorship Program by CAST YESS20160004+2 种基金Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China(Grant No.161053)project of China Scholarship Council(CSC)the Fundamental Research Funds for the Central Universities(2019MS006).
文摘Charge accumulation on the spacer surface in gas insulated equipment is very severe in the DC field,leading to easy flashover,which restricts the application of DC GIS/GIL.Therefore,knowledge about the charge accumulation characteristics of gas insulated equipment at DC stress is essential.In this paper,we reviewed the research methods and the characteristics of charge accumulation on spacers.A summary of charge measurement methods and setups are presented.And the surface charge inversion algorithms are introduced.Then the simulation model for charge accumulation in the DC field is reviewed.Subsequently,the charge accumulation mechanisms and phenomenon,the influence factor of surface charge accumulation and the influence of accumulated charge on spacer insulation characteristics are summarized.In addition,some suppression methods of surface charge accumulation are discussed.Finally,based on the understanding of charge accumulation on spacers,some suggestions on further studies are presented to aid in the design of a better spacer free from surface charges.
基金Supported by the National Key Research and Development Program of China(2016YFC0802502)。
文摘Regulator station is an important part in the urban gas transmission and distribution system.Once gas explosion occurs,the real explosion process and consequences of methane gas explosion in the regulator station were not revealed systematically.In this study,a full-scale experiment was carried out to simulate the regulator station explosion process,and some numerical simulations with a commercial CFD software called FLACS were conducted to analyze the effect of ignition and vent conditions on the blast overpressure and flame propagation.The experimental results demonstrated that the peak overpressure increased as the distance from the vent increased within a certain distance.And the maximum overpressure appeared 3 m away from the door,which was about 36.6 kPa.It was found that the pressure-time rising curves obtained from the simulation are basically the same as the ones from the experiment,however,the time of reaching the peak pressure was much shorter.The numerical simulation results show that the peak overpressures show an increase trend as the ignition height decreased and the vent relief pressure increased.It indicates that the damage and peak overpressure of gas explosion could be well predicted by FLACS in different styles of regulator station.In addition,the results help us to understand the internal mechanism and development process of gas explosion better.It also offers technical support for the safety protection of the urban regulator station.
基金Islamic Azad University(IAU)Shahrood Branch,Shahrood,IranGolestan Province Gas Company,Gorgan,Iran for their sponsorships.
文摘Natural gas is transported from producing regions to consumption regions by using transmission pipelines at high pressures. At consumption regions, the pressure of natural gas is reduced in city gate stations(CGSs). Before the pressure reduction process, the temperature of natural gas is increased usually by using a water bath heater,which burns natural gas as fuel, to protect against freezing of natural gas. These types of heat exchangers have a low efficiency and consume a lot of fuel to generate the required heat. In the current study, the twisted configuration of the heating coil is proposed and investigated to enhance the heat transfer through a water bath heater with a nominal capacity of 1000 m^3·h^-1. Firstly, the implementation procedure is validated with data collected from the CGS of Qaleh-Jiq(located in Golestan province of Iran). A very good agreement is achieved between the obtained results and the real data. Then, three different twist ratios are considered to examine the twisting effects. The proposed technique is evaluated in the terms of velocity, temperature, and pressure variations, and the results are compared with the conventional case, i.e. straight configuration. It is found that both the heat transfer rate and the pressure drop augment as the twist ratio is raised. Finally, it is concluded that the twisted tubes can reduce the length of the gas coil by about 12.5% for the model with low twist ratio, 18.75% for the model with medium twist ratio, and 25% for the model with high twist ratio as compared to the straight configuration.
基金the support from the National Science Foundation of China(Grant 71822105)。
文摘Optimal operation of a compressor station is important since it accounts for 25%to 50%of a company’s total operating budget.In short-term management of a compressor station,handling demand uncertainty is important yet challenging.Previous studies either require precise information about the distribution of uncertain parameters or greatly simplify the compressor model.We build a two-stage robust optimization framework of power cost minimization in a natural gas compressor station with nonidentical compressors.In the first stage,decision variables are the ON/OFF state of each compressor and discharge pressure.The worst-case cost of the second stage is incorporated in the first stage.Firststage decision variables feasibility is discussed and proper feasibility cuts are also proposed for the first stage.We employ a piece-wise approximation and propose accelerate methods.Our numerical results highlight two advantages of robust approach when managing uncertainty in practical settings:(1)the feasibility of first-stage decision can be increased by up to 45%,and(2)the worst-case cost can be reduced by up to 25%compared with stochastic programming models.Furthermore,our numerical experiments show that the designed accelerate algorithm has time improvements of 1518.9%on average(3785.9%at maximum).
基金Supported by the National Key Research and Development Program of China (Grant No.2020YFA0406000)the Scientific Instrument Development Project of the Chinese Academy of Sciences (Grant No.284(2018))the National Natural Science Foundation of China (Grant No.11875265)。
文摘At the China Spallation Neutron Source(CSNS), we have developed a custom gas-filling station, a glassblowing workshop, and a spin-exchange optical pumping(SEOP) system for producing high-quality ^(3)He-based neutron spin filter(NSF) cells. The gas-filling station is capable of routinely filling ^(3)He cells made from GE180 glass of various dimensions, to be used as neutron polarizers and analyzers on beamlines at the CSNS. Performance tests on cells fabricated at our gas-filling station are conducted via neutron transmission and nuclear-magneticresonance measurements, revealing nominal filling pressures, and a saturated ~3He polarization in the region of 80%, with a lifetime of approximately 240 hours. These results demonstrate our ability to produce competitive NSF cells to meet the ever-increasing research needs of the polarized neutron research community.
文摘The design of the pumping stations and the gas injection systems for the inner Chamber and the cryostat on HT-7U superconducting tokamak is described in this paper.