High-precision methane gas detection is of great importance in industrial safety, energy production and environmental protection, etc. However, in the existing measurement techniques, the methane gas concentration inf...High-precision methane gas detection is of great importance in industrial safety, energy production and environmental protection, etc. However, in the existing measurement techniques, the methane gas concentration information is susceptible to noise, which leads to its useful signal being drowned by noise. A fusion algorithm of variational modal decomposition(VMD) and improved wavelet threshold filtering is proposed, which is used in combination with tunable diode laser absorption spectroscopy(TDLAS) to implement a non-contact, high-resolution methane gas concentration detection. The fusion algorithm can perform noise reduction and further segmentation of the methane gas detection signal. And the simulation and experiment verify the effectiveness of the fusion algorithm, and the experimental results show that for the detection of air containing 10 ppm, 30 ppm, 60 ppm, 80 ppm, and 99 ppm methane, the errors are 12.75%, 8.18%, 3.37%, 2.46%, and 1.78%, respectively.展开更多
Passive Fourier transform infrared (FTIR) remote sensing measurement of chemical gas cloud is a vital technology. It takes an important part in many fields for the detection of released gases. The principle of conce...Passive Fourier transform infrared (FTIR) remote sensing measurement of chemical gas cloud is a vital technology. It takes an important part in many fields for the detection of released gases. The principle of concentration measurement is based on the Beer-Lambert law. Unlike the active measurement, for the passive remote sensing, in most cases, the difference between the temperature of the gas cloud and the brightness temperature of the background is usually a few kelvins. The gas cloud emission is almost equal to the background emission, thereby the emission of the gas cloud cannot be ignored. The concentration retrieval algorithm is quite different from the active measurement. In this paper, the concentration retrieval algorithm for the passive FTIR remote measurement of gas cloud is presented in detail, which involves radiative transfer model, radiometric calibration, absorption coefficient calculation, et al. The background spectrum has a broad feature, which is a slowly varying function of frequency. In this paper, the background spectrum is fitted with a polynomial by using the Levenberg-Marquardt method which is a kind of nonlinear least squares fitting algorithm. No background spectra are required. Thus, this method allows mobile, real-time and fast measurements of gas clouds.展开更多
By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their ye...By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their year-on-year changes, the distribution characteristics of oil and gas production and their year-on-year changes, and the development potential of oil and gas to be tapped in 2021, this paper sorts out systematically the current status and characteristics of global oil and gas development, summaries the major trends of global oil and gas development, puts forward enlightenment for international oil and gas cooperation. In 2021, oil and gas fields were widely distributed, the number of non-producing oil and gas fields was large;the whole oil and gas remaining recoverable reserves declined slightly, unconventional oil and gas remaining recoverable reserves dropped significantly;the overall oil and gas production continuously increased, the outputs of key resource-host countries kept year-on-year growth;undeveloped oilfields had abundant reserves and great development potential. Combined with global oil and gas geopolitics, oil and gas industry development trends, oil and gas investment intensity, and the tracking and judgment of hotspot fields, the major trends of global oil and gas development in 2021 are summarized. On this basis, the four aspects of enlightenment and suggestions for international oil and gas cooperation and development strategies are put forward: attach great importance to the obligation of marine abandonment to ensure high-quality and long-term benefit development of offshore oil and gas;adhere to the principle of not going to dangerous and chaotic places, strengthen the concentration of oil and gas assets, and establish multi stable supply bases;based on the multi-scenario demand of natural gas, realize the transformation from integrated collaboration to full oil and gas industry chain development;increase the acquisition of high-quality large-scale assets, and pay attention to the continuous optimization of the shareholding ratio of projects at different stages.展开更多
To thoroughly study the extinguishing effect of a high-pressure water mist fire extinguishing system when a transformer fire occurs,a 3D experimental model of a transformer is established in this work by employing Fir...To thoroughly study the extinguishing effect of a high-pressure water mist fire extinguishing system when a transformer fire occurs,a 3D experimental model of a transformer is established in this work by employing Fire Dynamics Simulator(FDS)software.More specifically,by setting different parameters,the process of the highpressure water mist fire extinguishing system with the presence of both diverse ambient temperatures and water mist sprinkler laying conditions is simulated.In addition,the fire extinguishing effect of the employed high-pressure water mist system with the implementation of different strategies is systematically analyzed.The extracted results show that a fire source farther away fromthe centerline leads to a lower local temperature distribution.In addition,as the ambient temperature increases,the temperature above the fire source decreases,while the temperature and the concentrationof theupperflue gas layer bothdecrease.Interestingly,after thehigh-pressurewatermist sprinkler begins to operate,both the temperature distribution above the fire source and the concentration of the flue gas decrease,which indicates that the high-pressure water mist system plays the role of cooling and dust removal.By comparing various sprinkler laying methods,it is found that the lower sprinkler height has a better effect on the temperature above the fire source,the temperature of the upper flue gas layer,and the concentration of the flue gas.Moreover,when the sprinkler is spread over thewhole transformer,the cooling effect on both the temperature above the fire source and the temperature of the upper flue gas layer is good,whereas the change in the concentration of the flue gas above the fire source is not obvious compared to the case where the sprinkler is not fully spread.展开更多
In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion process.SRFs are commonly produced by dr...In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion process.SRFs are commonly produced by drying combustible waste and removing incombustible matter,resulting in a higher combustibility as compared to the original waste.However,the characteristics of SRFs may highly vary depending on where and from which materials they were produced.Thus,we investigated the characteristics of various SRFs using thermogravimetric analysis(TGA).As a TGA sample is commonly small,on the scale of milligrams,and,unlike homogeneous fuels,SRFs are heterogeneous,individual SRF samples analysed with this method may not represent the bulk material,and sample properties may vary significantly between batches.Therefore,we further performed combustion experiments using a small-scale combustor and sample sizes from 1 to 10 g.To optimise SRF combustor design and determine the SRF characteristics,proximate,elemental,heating value,TG,and differential thermogravimetric analyses were conducted,and weight losses and gas concentrations at different temperatures were measured upon combustion.The lower heating values of the three analysed SRFs were 20,976,16,873,and 19,762 kJ/kg,and their Cl contents were 0.89,0.95,and 1.27 wt.%(legal criterion[Cl]<2.0 wt.%).TGA and small combustor experiments showed that complete weight loss was achieved below 500°C.However,CO was detected until 620°C.展开更多
Based on piezoelectric ultrasound technology,the paper theoretically analyses the determination of gas concentration and presents a norm-contrast method,which is realized by high-speed chip CPLD (Complex programmable ...Based on piezoelectric ultrasound technology,the paper theoretically analyses the determination of gas concentration and presents a norm-contrast method,which is realized by high-speed chip CPLD (Complex programmable logic device),to determine the concentration of SF_6 accurately with air as background.It is proved that this sensor can determine the concentration of SF_6 with the precision of 50μg/g.The sensor is in the process of producing.展开更多
Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition, surface and fracture morphologies of the specimen were c...Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition, surface and fracture morphologies of the specimen were characterized by using XRD and SEM, respectively. Ionic conduction was researched by gas concentration cell, the performance of hydrogen-air fuel cell was measured in the temperature range of 600~1000 ℃, and compared them with those of BaCe_(0.8)Eu_(0.2)O_(3-α) and Ba_(0.98)Ce_(0.8)Eu_(0.2)O_(3-α). The results indicate that Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) is a single-phase perovskite-type orthorhombic system. It is a pure proton conductor in the temperature range of 600~1000 ℃ in hydrogen atmosphere, and its proton conduction is superior to that of BaCe_(0.8)Eu_(0.2)O_(3-α) and Ba_(0.98)Ce_(0.8)Eu_(0.2)O_(3-α). It is a mixed conductor of oxide ion and electron hole in oxygen atmosphere. At 1000 ℃, the performance of the fuel cell in which Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) as electrolyte is higher than that of BaCe_(0.8)Eu_(0.2)O_(3-α) or Ba_(0.98)Ce_(0.8)Eu_(0.2)O_(3-α).展开更多
Blockage in water-dominated flow pipelines due to hydrate reformation has been suggested as a potential safety issue during the hydrate production.In this work,flow velocity-dependent hydrate formation features are in...Blockage in water-dominated flow pipelines due to hydrate reformation has been suggested as a potential safety issue during the hydrate production.In this work,flow velocity-dependent hydrate formation features are investigated in a fluid circulation system with a total length of 39 m.A 9-m section pipe is transparent consisted of two complete rectangular loops.By means of pressurization with gas-saturated water,the system can gradually reach the equilibrium conditions.The result shows that the hydrates are delayed to appear as floccules or thin films covering the methane bubbles.When the circulation velocity is below 750 rpm,hydrate is finally deposited as a“hydrate bed”at upmost of inner wall,narrowing the flow channel of the pipeline.Nevertheless,no plugging is observed during all the experimental runs.The five stages of hydrate deposition are proposed based on the experimental results.It is also revealed that a higher driving pressure is needed at a lower flow rate.The driving force of hydrate formation from gas and water obtained by melting hydrate is higher than that from fresh water with no previous hydrate history.The authors hope that this work will be beneficial for the flow assurance of the following oceanic field hydrate recovery trials.展开更多
Proton-conducting SrCe0.9Ho0.1O3-α ceramics was prepared by high-temperature solid state reaction. X-ray powder diffraction patterns show that the ceramics is of a single orthorhombic phase of perovskite-type SrCe03....Proton-conducting SrCe0.9Ho0.1O3-α ceramics was prepared by high-temperature solid state reaction. X-ray powder diffraction patterns show that the ceramics is of a single orthorhombic phase of perovskite-type SrCe03. Using the ceramics as solid electrolyte and porous platinum as electrodes, the protonic conduction in the ceramics was investigated by using ac impedance spectroscopy and gas concentration cell methods in the temperature range of 600 ~ 1000 ℃.展开更多
A case study was performed in Beijing in 2000 to observe concentrations of SO2 and NOx in the atmosphere and to evaluate their radiative impact. It was found that the concentrations of these gases are usually high in ...A case study was performed in Beijing in 2000 to observe concentrations of SO2 and NOx in the atmosphere and to evaluate their radiative impact. It was found that the concentrations of these gases are usually high in the morning due to a temperature inversion in the boundary layer. The average concentrations obtained from the observations are much higher than those used in the McClatchey reference atmosphere. The radiative impacts of these gases are calculated using a line-by-line radiative transfer model. The results show that the radiative forcing at the surface due to SO2 is 0.0576 W m^-2 and that due to NOx is 0.0032 W m^-2. These figures are almost compatible with that due to CFC11.展开更多
BaxCe0.8Pr0.2O3-α (x=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas...BaxCe0.8Pr0.2O3-α (x=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 °C. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba1.03Ce0.8Pr0.2O3-α was a pure protonic conductor, and Ba0.98Ce0.8Pr0.2O3-α was a mixed conductor of protons and electrons in wet hydrogen at 500-900 °C. BaCe0.8Pr0.2O3-α was a pure protonic conductor in 500-600 °C, and a mixed conductor of protons and electrons above 600 °C in wet hydrogen. In 500-900 °C, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed conductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing barium content in the materials in wet hydrogen, dry air and wet air, respectively.展开更多
Incessant fire-outbreak in urban settlements has remained intractable especially in developing countries like Nigeria. This is often characterized by grave socio-economic aftermath effects. Urban fire outbreak in Nige...Incessant fire-outbreak in urban settlements has remained intractable especially in developing countries like Nigeria. This is often characterized by grave socio-economic aftermath effects. Urban fire outbreak in Nigerian cities has been on increase in recent times. The major problem faced by fire fighters in Nigerian urban centres is that there are no mechanisms to detect fire outbreaks early enough to save lives and properties. They often rely on calls made by neighbours or occupants when an outbreak occurs and this accounts for the delay in fighting fire outbreaks. This work uses Artificial Neural Networks (ANN) with backpropagation method to detect the occurrence of urban fires. The method uses smoke density, room temperature and cooking gas concentration as inputs. The work was implemented using Java programming language and results showed that it detected the occurrence of urban fires with reasonable accuracy. The work is recommended for use to minimize the effect of urban fire outbreak.展开更多
There are many factors,that affect the development of indoor fire,such as the size of the fire source,the opening or space of the room,and the nature of the combustible materials.Among them,the space of the room,has a...There are many factors,that affect the development of indoor fire,such as the size of the fire source,the opening or space of the room,and the nature of the combustible materials.Among them,the space of the room,has a significant impact on the development of a ventilation-limited fire.In this paper,the Fire Dynamics Simulator(FDS)software is used to analyze,the risk of fire initiation in the restricted ventilated compartment,when the size of vertical ventilation space is different.Through,a combination of experimental design,numerical simulation,and theoretical analysis,the changes in the level of carbon monoxide,visibility,temperature,Heat Release Rate(HRR)and,the smoke exhaust efficiency of natural smoke at different opening sizes are observed.It is observed that,when the ratio of inlet and outlet area reaches 2:1,the natural smoke exhaust effect is the best,however,the increasing in the opening size has little significance on the smoke exhaust effect.The research on the influence of smoke outlet size,will helps in the development of the law regarding fire prevention,smoke exhaust design,and fire rescue work of a building.展开更多
H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formati...H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formation of SO_(2) and catalyst deactivation inevitably occur, due to the temperature rise of fixed reaction bed caused by the exothermic reaction. Catalyst with high activity in wide operating temperature window, especially in high temperature range, is urgently needed. In this paper, a series of copper-substituted hexaaluminate catalysts (LaCu_(x), x = 0, 0.5, 1, 1.5, 2, 2.5) were prepared and investigated for the H_(2)S selective oxidation reaction at high temperature conditions (300-550℃). The LaCu_(1) catalyst exhibited excellent catalytic performance and great stability, which was attributed to the best reductive properties and proper pore structure. Besides, two facile deep processing paths were proposed to eliminate the remaining H_(2)S and SO_(2) in the tail gas.展开更多
Underground structures are normally located in highly-confined and congested spaces,which may lead to severe gas explosion accidents,with significant human and economic losses.For accurately evaluating the consequence...Underground structures are normally located in highly-confined and congested spaces,which may lead to severe gas explosion accidents,with significant human and economic losses.For accurately evaluating the consequences of these explosions,a variety of influencing factors need to be considered,including concentrations of gas mixtures,vent conditions,obstacles,and ignition features.Moreover,a good review on these influencing factors is important for a better understanding of explosion behavior,e.g.,the deflagration to detonation phenomenon.In this study,some critical influencing factors for gas explosions in underground or confined spaces are investigated,and the effects of the factors on such gas explosions are examined.The results are discussed,along with findings from literature.The present study provides a reference for future studies on safety management and consequence mitigation for underground gas explosions.展开更多
Due to the influence of many factors,the overpressure-time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design.Based on vented gas explosion test data...Due to the influence of many factors,the overpressure-time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design.Based on vented gas explosion test data,this paper obtains three typical overpressure-time history curves and puts forward a new semi-empirical model-double hump model that considers gas concentration and venting pressure,and gives a formula for peak pressure and overpressure-time history model.The scientificity of the model is then verified by the total impulse in the load.The model is able directly reflect the load characteristics,provide reference for calculating key parameters of a vented gas explosion and provide information on the structural response under the load.The model thereby has the potential to help reduce the impact of gas explosion disasters.展开更多
A new series of Zr1-xInxP2O7 (x=0.03, 0.06, 0.09, 0.12) samples were prepared by a solid state reaction method. XRD patterns indicated that the samples of x=0.03–0.09 exhibited a single cubic phase structure, and t...A new series of Zr1-xInxP2O7 (x=0.03, 0.06, 0.09, 0.12) samples were prepared by a solid state reaction method. XRD patterns indicated that the samples of x=0.03–0.09 exhibited a single cubic phase structure, and the doping limit of In3+ in ZrP2O7 was x=0.09. The conduction behavior was investigated in wet hydrogen using various electrochemical methods including AC impedance spectroscopy, isotope effect, gas concentration cells at intermediate temperatures (373–573 K). The conductivities were affected by the doping levels, and increased in the order: σ (x=0.03)〈σ (x=0.12)〈σ (x=0.06)〈σ (x=0.09). The highest conductivity was observed for the sample Zr0.91In0.09P2O7 to be 1.59×10-2 S·cm-1 in wet hydrogen at 573 K. The isotope effect also confirmed the proton conduction of the sample under water vapor-containing atmosphere. It was found that in wet hydrogen atmosphere Zr0.91In0.09P2O7 was almost pure ionic conductor, the ionic conduction was contributed mainly to proton and partially to oxide ionic. The H2/air fuel cell using x=0.09 sample as electrolyte (thickness: 1.73 mm) generated a maximum power density of 13.5 mW·cm?2 at 423 K and 16.9 mW·cm?2 at 448 K, respectively.展开更多
Ba0.95Ce0.8Ho0.2O3-a was prepared by high temperature solid-state reaction. X-ray diffraction (XRD) pattern showed that the material was of a single perovskite-type orthorhombic phase. Using the material as solid el...Ba0.95Ce0.8Ho0.2O3-a was prepared by high temperature solid-state reaction. X-ray diffraction (XRD) pattern showed that the material was of a single perovskite-type orthorhombic phase. Using the material as solid electrolyte and porous platinum as electrodes, the measurements of ionic transport number and conductivity of Ba0.95Ce0.8Ho0.2O3-a were performed by gas concentration cell and ac impedance spectroscopy methods in the temperature range of 600---1000 ℃in wet hydrogen, dry and wet air respectively. Ionic conduction of the material was investigated and compared with that of BaCe0.8Ho0.2O3-a. The results indicated that Ba0.95Ce0.8Ho0.2O3-a was a pure protonic conductor with the protonic transport number of 1 during 600---700℃ in wet hydrogen, a mixed conductor of protons and electrons with the protonic transport number of 0.97--0.93 in 800---1000 ℃. But BaCe0.8Ho0.2O3-a was almost a pure protonic conductor with the protonic transport number of 1 in 600---900 ℃ and 0.99 at 1000 ℃ in wet hydrogen. In dry air and in the temperature range of 600---1000 ℃, they were both mixed conductors of oxide ions and electronic holes, and the oxide-ionic transport numbers were 0.24--0.33 and 0.17--0.30 respectively. In wet air and in the temperature range of 600---1000 ℃, they were both mixed conductors of protons, oxide ions and electronic holes, the protonic transport numbers were 0.11--0.00 and 0.09--0.01 respectively, and the oxide-ionic transport numbers were 0.41--0.33 and 0.27--0.30 respectively. Protonic conductivity of Ba0.95Ce0.8Ho0.2O3-a in both wet hydrogen and wet air was higher than that of BaCe0.8Ho0.2O3-a in 600--- 800 ℃, but lower in 900--1000 ℃. Oxide-ionic conductivity of the material was higher than that of BaCe0.8Ho0.2O3-a in both dry air and wet air in 600---1000 ℃.展开更多
BaBa1.03Ce0.8Tm0.2O3-aceramic with orthorhombic perovskite structure was prepared by conventional solid-state reaction. The conductivity and ionic transport number of BaBa1.03Ce0.8Tm0.2O3-a a were measured by ac imped...BaBa1.03Ce0.8Tm0.2O3-aceramic with orthorhombic perovskite structure was prepared by conventional solid-state reaction. The conductivity and ionic transport number of BaBa1.03Ce0.8Tm0.2O3-a a were measured by ac impedance spectroscopy and gas concentration cell methods in the temperature range of 500-900 ℃ in wet hydrogen and wet air. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance was examined at 500-900℃. The results indicate that the specimen is a pure ionic conductor with the ionic transport number of 1 at 500-900 ℃ in wet hydrogen. In wet air, the specimen is a mixed conductor of proton, oxide ion and electron hole. The protonic transport numbers are 0.071-0.018, and the oxide ionic transport numbers are 0.273-0.365. The conductivities of Bal.03Ceo.sTmo.203 a under wet hydrogen, wet air or fuel cell atmosphere are higher than those of BaBa1.03Ce0.8Tm0.2O3-a a (RE=Y, Eu, Ho) reported previously by us. The fuel cell can work stably. At 900℃ the maximum power output density is 122.7 mWocm 2, which is higher than that of our previous cell using BaBa1.03Ce0.8Tm0.2O3-a(RE=Y, Eu, Ho) as electrolyte.展开更多
基金supported by the Project Grant from Heilongjiang Bayi Agricultural Reclamation University,Heilongjiang,China (No.XDB201813)。
文摘High-precision methane gas detection is of great importance in industrial safety, energy production and environmental protection, etc. However, in the existing measurement techniques, the methane gas concentration information is susceptible to noise, which leads to its useful signal being drowned by noise. A fusion algorithm of variational modal decomposition(VMD) and improved wavelet threshold filtering is proposed, which is used in combination with tunable diode laser absorption spectroscopy(TDLAS) to implement a non-contact, high-resolution methane gas concentration detection. The fusion algorithm can perform noise reduction and further segmentation of the methane gas detection signal. And the simulation and experiment verify the effectiveness of the fusion algorithm, and the experimental results show that for the detection of air containing 10 ppm, 30 ppm, 60 ppm, 80 ppm, and 99 ppm methane, the errors are 12.75%, 8.18%, 3.37%, 2.46%, and 1.78%, respectively.
基金Project supported by the National Natural Science Foundation of China (Grant No 083H311501)the National High Technology Research and Development Program of China (Grant No 073H3f1514)
文摘Passive Fourier transform infrared (FTIR) remote sensing measurement of chemical gas cloud is a vital technology. It takes an important part in many fields for the detection of released gases. The principle of concentration measurement is based on the Beer-Lambert law. Unlike the active measurement, for the passive remote sensing, in most cases, the difference between the temperature of the gas cloud and the brightness temperature of the background is usually a few kelvins. The gas cloud emission is almost equal to the background emission, thereby the emission of the gas cloud cannot be ignored. The concentration retrieval algorithm is quite different from the active measurement. In this paper, the concentration retrieval algorithm for the passive FTIR remote measurement of gas cloud is presented in detail, which involves radiative transfer model, radiometric calibration, absorption coefficient calculation, et al. The background spectrum has a broad feature, which is a slowly varying function of frequency. In this paper, the background spectrum is fitted with a polynomial by using the Levenberg-Marquardt method which is a kind of nonlinear least squares fitting algorithm. No background spectra are required. Thus, this method allows mobile, real-time and fast measurements of gas clouds.
基金Scientific Research and Technology Development Project(2021DJ3205)。
文摘By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their year-on-year changes, the distribution characteristics of oil and gas production and their year-on-year changes, and the development potential of oil and gas to be tapped in 2021, this paper sorts out systematically the current status and characteristics of global oil and gas development, summaries the major trends of global oil and gas development, puts forward enlightenment for international oil and gas cooperation. In 2021, oil and gas fields were widely distributed, the number of non-producing oil and gas fields was large;the whole oil and gas remaining recoverable reserves declined slightly, unconventional oil and gas remaining recoverable reserves dropped significantly;the overall oil and gas production continuously increased, the outputs of key resource-host countries kept year-on-year growth;undeveloped oilfields had abundant reserves and great development potential. Combined with global oil and gas geopolitics, oil and gas industry development trends, oil and gas investment intensity, and the tracking and judgment of hotspot fields, the major trends of global oil and gas development in 2021 are summarized. On this basis, the four aspects of enlightenment and suggestions for international oil and gas cooperation and development strategies are put forward: attach great importance to the obligation of marine abandonment to ensure high-quality and long-term benefit development of offshore oil and gas;adhere to the principle of not going to dangerous and chaotic places, strengthen the concentration of oil and gas assets, and establish multi stable supply bases;based on the multi-scenario demand of natural gas, realize the transformation from integrated collaboration to full oil and gas industry chain development;increase the acquisition of high-quality large-scale assets, and pay attention to the continuous optimization of the shareholding ratio of projects at different stages.
基金supported by Science and Technology Projects Funded by State Grid Corporation of China (5200202024105A0000).
文摘To thoroughly study the extinguishing effect of a high-pressure water mist fire extinguishing system when a transformer fire occurs,a 3D experimental model of a transformer is established in this work by employing Fire Dynamics Simulator(FDS)software.More specifically,by setting different parameters,the process of the highpressure water mist fire extinguishing system with the presence of both diverse ambient temperatures and water mist sprinkler laying conditions is simulated.In addition,the fire extinguishing effect of the employed high-pressure water mist system with the implementation of different strategies is systematically analyzed.The extracted results show that a fire source farther away fromthe centerline leads to a lower local temperature distribution.In addition,as the ambient temperature increases,the temperature above the fire source decreases,while the temperature and the concentrationof theupperflue gas layer bothdecrease.Interestingly,after thehigh-pressurewatermist sprinkler begins to operate,both the temperature distribution above the fire source and the concentration of the flue gas decrease,which indicates that the high-pressure water mist system plays the role of cooling and dust removal.By comparing various sprinkler laying methods,it is found that the lower sprinkler height has a better effect on the temperature above the fire source,the temperature of the upper flue gas layer,and the concentration of the flue gas.Moreover,when the sprinkler is spread over thewhole transformer,the cooling effect on both the temperature above the fire source and the temperature of the upper flue gas layer is good,whereas the change in the concentration of the flue gas above the fire source is not obvious compared to the case where the sprinkler is not fully spread.
基金supported by the Korea Environment Industry&Technology Institute(KEITI)through a Public Technology Program based on the Environmental Policy Program funded by the Korea Ministry of Environment(MOE)[Grant number:2016000710008].
文摘In the production(as co-fuel or alone)of solid refuse fuel(SRF),knowledge about the characteristics of the raw materials is required for an ecofriendly and effective combustion process.SRFs are commonly produced by drying combustible waste and removing incombustible matter,resulting in a higher combustibility as compared to the original waste.However,the characteristics of SRFs may highly vary depending on where and from which materials they were produced.Thus,we investigated the characteristics of various SRFs using thermogravimetric analysis(TGA).As a TGA sample is commonly small,on the scale of milligrams,and,unlike homogeneous fuels,SRFs are heterogeneous,individual SRF samples analysed with this method may not represent the bulk material,and sample properties may vary significantly between batches.Therefore,we further performed combustion experiments using a small-scale combustor and sample sizes from 1 to 10 g.To optimise SRF combustor design and determine the SRF characteristics,proximate,elemental,heating value,TG,and differential thermogravimetric analyses were conducted,and weight losses and gas concentrations at different temperatures were measured upon combustion.The lower heating values of the three analysed SRFs were 20,976,16,873,and 19,762 kJ/kg,and their Cl contents were 0.89,0.95,and 1.27 wt.%(legal criterion[Cl]<2.0 wt.%).TGA and small combustor experiments showed that complete weight loss was achieved below 500°C.However,CO was detected until 620°C.
基金This work was supported by National Natural Science Foundation of China (10574038);development project of high-tech industry of universities in Jiangsu (JHB05-08);Changzhou scientific and technological bureau (CE2005026).
文摘Based on piezoelectric ultrasound technology,the paper theoretically analyses the determination of gas concentration and presents a norm-contrast method,which is realized by high-speed chip CPLD (Complex programmable logic device),to determine the concentration of SF_6 accurately with air as background.It is proved that this sensor can determine the concentration of SF_6 with the precision of 50μg/g.The sensor is in the process of producing.
文摘Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition, surface and fracture morphologies of the specimen were characterized by using XRD and SEM, respectively. Ionic conduction was researched by gas concentration cell, the performance of hydrogen-air fuel cell was measured in the temperature range of 600~1000 ℃, and compared them with those of BaCe_(0.8)Eu_(0.2)O_(3-α) and Ba_(0.98)Ce_(0.8)Eu_(0.2)O_(3-α). The results indicate that Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) is a single-phase perovskite-type orthorhombic system. It is a pure proton conductor in the temperature range of 600~1000 ℃ in hydrogen atmosphere, and its proton conduction is superior to that of BaCe_(0.8)Eu_(0.2)O_(3-α) and Ba_(0.98)Ce_(0.8)Eu_(0.2)O_(3-α). It is a mixed conductor of oxide ion and electron hole in oxygen atmosphere. At 1000 ℃, the performance of the fuel cell in which Ba_(1.03)Ce_(0.8)Eu_(0.2)O_(3-α) as electrolyte is higher than that of BaCe_(0.8)Eu_(0.2)O_(3-α) or Ba_(0.98)Ce_(0.8)Eu_(0.2)O_(3-α).
基金funded by the National Natural Science Foundation of China(42076217,41976205)Shandong Provincial Taishan Scholars Special Expert Project (ts201712079)+1 种基金Marine Geological Survey Program (DD20190231)Shandong Natural Science Foundation(ZR2017BD024)。
文摘Blockage in water-dominated flow pipelines due to hydrate reformation has been suggested as a potential safety issue during the hydrate production.In this work,flow velocity-dependent hydrate formation features are investigated in a fluid circulation system with a total length of 39 m.A 9-m section pipe is transparent consisted of two complete rectangular loops.By means of pressurization with gas-saturated water,the system can gradually reach the equilibrium conditions.The result shows that the hydrates are delayed to appear as floccules or thin films covering the methane bubbles.When the circulation velocity is below 750 rpm,hydrate is finally deposited as a“hydrate bed”at upmost of inner wall,narrowing the flow channel of the pipeline.Nevertheless,no plugging is observed during all the experimental runs.The five stages of hydrate deposition are proposed based on the experimental results.It is also revealed that a higher driving pressure is needed at a lower flow rate.The driving force of hydrate formation from gas and water obtained by melting hydrate is higher than that from fresh water with no previous hydrate history.The authors hope that this work will be beneficial for the flow assurance of the following oceanic field hydrate recovery trials.
文摘Proton-conducting SrCe0.9Ho0.1O3-α ceramics was prepared by high-temperature solid state reaction. X-ray powder diffraction patterns show that the ceramics is of a single orthorhombic phase of perovskite-type SrCe03. Using the ceramics as solid electrolyte and porous platinum as electrodes, the protonic conduction in the ceramics was investigated by using ac impedance spectroscopy and gas concentration cell methods in the temperature range of 600 ~ 1000 ℃.
基金This work was supported by the project of"Research on the Supporting Technology of Atmospheric Environment for the Sustainable Urban Planning"from China Rural Technology Development Center,Beijing Natural Science Foundation(No.8051002)National Natural Science Foundation of China(No.40505002).
文摘A case study was performed in Beijing in 2000 to observe concentrations of SO2 and NOx in the atmosphere and to evaluate their radiative impact. It was found that the concentrations of these gases are usually high in the morning due to a temperature inversion in the boundary layer. The average concentrations obtained from the observations are much higher than those used in the McClatchey reference atmosphere. The radiative impacts of these gases are calculated using a line-by-line radiative transfer model. The results show that the radiative forcing at the surface due to SO2 is 0.0576 W m^-2 and that due to NOx is 0.0032 W m^-2. These figures are almost compatible with that due to CFC11.
基金Project supported by the National Natural Science Foundation of China (20771079)Qing Lan Project and the Natural Science Foundation of Education Department of Jiangsu Province (07KJB150126 and 08KJD150008)
文摘BaxCe0.8Pr0.2O3-α (x=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 °C. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba1.03Ce0.8Pr0.2O3-α was a pure protonic conductor, and Ba0.98Ce0.8Pr0.2O3-α was a mixed conductor of protons and electrons in wet hydrogen at 500-900 °C. BaCe0.8Pr0.2O3-α was a pure protonic conductor in 500-600 °C, and a mixed conductor of protons and electrons above 600 °C in wet hydrogen. In 500-900 °C, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed conductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing barium content in the materials in wet hydrogen, dry air and wet air, respectively.
文摘Incessant fire-outbreak in urban settlements has remained intractable especially in developing countries like Nigeria. This is often characterized by grave socio-economic aftermath effects. Urban fire outbreak in Nigerian cities has been on increase in recent times. The major problem faced by fire fighters in Nigerian urban centres is that there are no mechanisms to detect fire outbreaks early enough to save lives and properties. They often rely on calls made by neighbours or occupants when an outbreak occurs and this accounts for the delay in fighting fire outbreaks. This work uses Artificial Neural Networks (ANN) with backpropagation method to detect the occurrence of urban fires. The method uses smoke density, room temperature and cooking gas concentration as inputs. The work was implemented using Java programming language and results showed that it detected the occurrence of urban fires with reasonable accuracy. The work is recommended for use to minimize the effect of urban fire outbreak.
文摘There are many factors,that affect the development of indoor fire,such as the size of the fire source,the opening or space of the room,and the nature of the combustible materials.Among them,the space of the room,has a significant impact on the development of a ventilation-limited fire.In this paper,the Fire Dynamics Simulator(FDS)software is used to analyze,the risk of fire initiation in the restricted ventilated compartment,when the size of vertical ventilation space is different.Through,a combination of experimental design,numerical simulation,and theoretical analysis,the changes in the level of carbon monoxide,visibility,temperature,Heat Release Rate(HRR)and,the smoke exhaust efficiency of natural smoke at different opening sizes are observed.It is observed that,when the ratio of inlet and outlet area reaches 2:1,the natural smoke exhaust effect is the best,however,the increasing in the opening size has little significance on the smoke exhaust effect.The research on the influence of smoke outlet size,will helps in the development of the law regarding fire prevention,smoke exhaust design,and fire rescue work of a building.
基金financially supported by the National Natural Science Foundation of China (Nos. 21976176, 22006148)the Key R&D Program of Shandong province (No. 2019JZZY010506)the Fundamental Research Funds for the Central Universities。
文摘H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formation of SO_(2) and catalyst deactivation inevitably occur, due to the temperature rise of fixed reaction bed caused by the exothermic reaction. Catalyst with high activity in wide operating temperature window, especially in high temperature range, is urgently needed. In this paper, a series of copper-substituted hexaaluminate catalysts (LaCu_(x), x = 0, 0.5, 1, 1.5, 2, 2.5) were prepared and investigated for the H_(2)S selective oxidation reaction at high temperature conditions (300-550℃). The LaCu_(1) catalyst exhibited excellent catalytic performance and great stability, which was attributed to the best reductive properties and proper pore structure. Besides, two facile deep processing paths were proposed to eliminate the remaining H_(2)S and SO_(2) in the tail gas.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51778029).
文摘Underground structures are normally located in highly-confined and congested spaces,which may lead to severe gas explosion accidents,with significant human and economic losses.For accurately evaluating the consequences of these explosions,a variety of influencing factors need to be considered,including concentrations of gas mixtures,vent conditions,obstacles,and ignition features.Moreover,a good review on these influencing factors is important for a better understanding of explosion behavior,e.g.,the deflagration to detonation phenomenon.In this study,some critical influencing factors for gas explosions in underground or confined spaces are investigated,and the effects of the factors on such gas explosions are examined.The results are discussed,along with findings from literature.The present study provides a reference for future studies on safety management and consequence mitigation for underground gas explosions.
基金The authors gratefully acknowledge the financial support from Natural Science Foundation of Jiangsu Province of China(Grant No.BK20180081)National Key R&D Program of China(Great No.2020YFB2103300)National Basic Research Program of China(973 Program)(Grant No.2015CB058000).
文摘Due to the influence of many factors,the overpressure-time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design.Based on vented gas explosion test data,this paper obtains three typical overpressure-time history curves and puts forward a new semi-empirical model-double hump model that considers gas concentration and venting pressure,and gives a formula for peak pressure and overpressure-time history model.The scientificity of the model is then verified by the total impulse in the load.The model is able directly reflect the load characteristics,provide reference for calculating key parameters of a vented gas explosion and provide information on the structural response under the load.The model thereby has the potential to help reduce the impact of gas explosion disasters.
文摘A new series of Zr1-xInxP2O7 (x=0.03, 0.06, 0.09, 0.12) samples were prepared by a solid state reaction method. XRD patterns indicated that the samples of x=0.03–0.09 exhibited a single cubic phase structure, and the doping limit of In3+ in ZrP2O7 was x=0.09. The conduction behavior was investigated in wet hydrogen using various electrochemical methods including AC impedance spectroscopy, isotope effect, gas concentration cells at intermediate temperatures (373–573 K). The conductivities were affected by the doping levels, and increased in the order: σ (x=0.03)〈σ (x=0.12)〈σ (x=0.06)〈σ (x=0.09). The highest conductivity was observed for the sample Zr0.91In0.09P2O7 to be 1.59×10-2 S·cm-1 in wet hydrogen at 573 K. The isotope effect also confirmed the proton conduction of the sample under water vapor-containing atmosphere. It was found that in wet hydrogen atmosphere Zr0.91In0.09P2O7 was almost pure ionic conductor, the ionic conduction was contributed mainly to proton and partially to oxide ionic. The H2/air fuel cell using x=0.09 sample as electrolyte (thickness: 1.73 mm) generated a maximum power density of 13.5 mW·cm?2 at 423 K and 16.9 mW·cm?2 at 448 K, respectively.
基金Project supported by theNat-ional Natural Science Foundation of China (No. 20171034) and the Natural Science Foundation of Education Department of Jiangsu Province (No. 07KJB 150126).
文摘Ba0.95Ce0.8Ho0.2O3-a was prepared by high temperature solid-state reaction. X-ray diffraction (XRD) pattern showed that the material was of a single perovskite-type orthorhombic phase. Using the material as solid electrolyte and porous platinum as electrodes, the measurements of ionic transport number and conductivity of Ba0.95Ce0.8Ho0.2O3-a were performed by gas concentration cell and ac impedance spectroscopy methods in the temperature range of 600---1000 ℃in wet hydrogen, dry and wet air respectively. Ionic conduction of the material was investigated and compared with that of BaCe0.8Ho0.2O3-a. The results indicated that Ba0.95Ce0.8Ho0.2O3-a was a pure protonic conductor with the protonic transport number of 1 during 600---700℃ in wet hydrogen, a mixed conductor of protons and electrons with the protonic transport number of 0.97--0.93 in 800---1000 ℃. But BaCe0.8Ho0.2O3-a was almost a pure protonic conductor with the protonic transport number of 1 in 600---900 ℃ and 0.99 at 1000 ℃ in wet hydrogen. In dry air and in the temperature range of 600---1000 ℃, they were both mixed conductors of oxide ions and electronic holes, and the oxide-ionic transport numbers were 0.24--0.33 and 0.17--0.30 respectively. In wet air and in the temperature range of 600---1000 ℃, they were both mixed conductors of protons, oxide ions and electronic holes, the protonic transport numbers were 0.11--0.00 and 0.09--0.01 respectively, and the oxide-ionic transport numbers were 0.41--0.33 and 0.27--0.30 respectively. Protonic conductivity of Ba0.95Ce0.8Ho0.2O3-a in both wet hydrogen and wet air was higher than that of BaCe0.8Ho0.2O3-a in 600--- 800 ℃, but lower in 900--1000 ℃. Oxide-ionic conductivity of the material was higher than that of BaCe0.8Ho0.2O3-a in both dry air and wet air in 600---1000 ℃.
基金Project supported by the National Natural Science Foundation of China (No. 20771079), Qing Lan Project and the Natural Science Foundation of Education Department of Jiangsu Province (No. 07KJB 150126).
文摘BaBa1.03Ce0.8Tm0.2O3-aceramic with orthorhombic perovskite structure was prepared by conventional solid-state reaction. The conductivity and ionic transport number of BaBa1.03Ce0.8Tm0.2O3-a a were measured by ac impedance spectroscopy and gas concentration cell methods in the temperature range of 500-900 ℃ in wet hydrogen and wet air. Using the ceramic as solid electrolyte and porous platinum as electrodes, the hydrogen-air fuel cell was constructed, and the cell performance was examined at 500-900℃. The results indicate that the specimen is a pure ionic conductor with the ionic transport number of 1 at 500-900 ℃ in wet hydrogen. In wet air, the specimen is a mixed conductor of proton, oxide ion and electron hole. The protonic transport numbers are 0.071-0.018, and the oxide ionic transport numbers are 0.273-0.365. The conductivities of Bal.03Ceo.sTmo.203 a under wet hydrogen, wet air or fuel cell atmosphere are higher than those of BaBa1.03Ce0.8Tm0.2O3-a a (RE=Y, Eu, Ho) reported previously by us. The fuel cell can work stably. At 900℃ the maximum power output density is 122.7 mWocm 2, which is higher than that of our previous cell using BaBa1.03Ce0.8Tm0.2O3-a(RE=Y, Eu, Ho) as electrolyte.