Using natural gas(NG)as the primary fuel helps alleviate the fossil fuel crisis while reducing engine soot and nitrogen oxide(NO_(X))emissions.In this paper,the influences of a novel split injection concept on an NG h...Using natural gas(NG)as the primary fuel helps alleviate the fossil fuel crisis while reducing engine soot and nitrogen oxide(NO_(X))emissions.In this paper,the influences of a novel split injection concept on an NG high pressure direct injection(HPDI)engine are examined.Four typical split injection strategies,namely split pre-injection of pilot diesel(PD)and NG,split post-injection of PD and NG,split pre-injection of NG,and split post-injection of PD,were developed to investigate the influences on combustion and emissions.Results revealed that split pre injection of NG enhanced the atomization of PD,whereas the split post-injection of NG lowered the temperature in the core region of the PD spray,resulting in the deterioration of combustion.The effect of the split injection strategy on indicated thermal efficiency exceeded 7.5%.Split pre-injection was favorable to enhancing thermal efficiency,whereas split post-injection was not.Ignition delay,combustion duration,and premixed combustion time proportion were affected by injection strategies by 3.8%,50%,and 19.7%,respectively.Split pre-injection increased CH_(4) emission in the exhaust.Split post-injection,especially split post-injection of PD and NG,reduced the unburned CH_(4) emission by approximately 30%.When the split post-injection ratio was less than 30%,the trade-off between NO_(X) and soot was interrupted.The distribution range of hydroxyl radicals was expanded by pre-injection,and NO_(X) was generated in the region where the NG jet hit the wall.This paper provides valuable insights into the optimization of HPDI injection parameters.展开更多
In the mid-21st century,natural gas will enter its golden age,and the era of natural gas is arriving.This paper reviews the development stages of global natural gas industry and the enlightenment of American shale gas...In the mid-21st century,natural gas will enter its golden age,and the era of natural gas is arriving.This paper reviews the development stages of global natural gas industry and the enlightenment of American shale gas revolution,summarizes the development history and achievements of the natural gas industry in China,analyzes the status and challenges of natural gas in the green and low-carbon energy transition,and puts forward the natural gas industry development strategies under carbon neutral target in China.The natural gas industry in China has experienced three periods:start,growth,and leap forward.At present,China has become the fourth largest natural gas producer and third largest natural gas consumer in the world,and has made great achievements in natural gas exploration and development theory and technology,providing important support for the growth of production and reserves.China has set its goal of carbon neutrality to promote green and sustainable development,which brings opportunities and challenges for natural gas industry.Natural gas has significant low-carbon advantages,and gas-electric peak shaving boosts new energy development;the difficulty and cost of development are more prominent.For the national energy security and harmonious development between economy and ecology under the carbon neutral goal,based on the principle of"comprehensive planning,technological innovation,multi-energy complementarity,diversified integration,flexibility and efficiency,optimization and upgrading",the construction of the production-supplystorage-marketing system has to be improved so as to boost the development of the natural gas industry.First,it is necessary to strengthen efforts in the exploration and development of natural gas,making projects and arrangement in key exploration and development areas,meanwhile,it is urgent to make breakthroughs in key science theories and technologies,so as to increase reserve and production.Second,it should promote green and innovative development of the natural gas by developing new techniques,expanding new fields and integrating with new energy.Third,there is a demand to realize transformation and upgrading of the supply and demand structure of natural gas by strengthening the layout of pipeline gas,liquefied natural gas and the construction of underground gas storage,establishing reserve system for improving abilities of emergency response and adjustment,raising the proportion of natural gas in the primary energy consumption and contributing to the transformation of energy consumption structure,realizing low-carbon resources utilization and clean energy consumption.展开更多
Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent N...Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.展开更多
The different reservoirs in deep Songliao Basin have non-homogeneous lithologies and include multiple layers with a high content of hydrogen gas.The gas composition and stable isotope characteristics vary significantl...The different reservoirs in deep Songliao Basin have non-homogeneous lithologies and include multiple layers with a high content of hydrogen gas.The gas composition and stable isotope characteristics vary significantly,but the origin analysis of different gas types has previously been weak.Based on the geochemical parameters of gas samples from different depths and the analysis of geological settings,this research covers the diverse origins of natural gas in different strata.The gas components are mainly methane with a small amount of C_(2+),and non-hydrocarbon gases,including nitrogen(N_(2)),hydrogen(H_(2)),carbon dioxide(CO_(2)),and helium(He).At greater depth,the carbon isotope of methane becomes heavier,and the hydrogen isotope points to a lacustrine sedimentary environment.With increasing depth,the origins of N_(2)and CO_(2)change gradually from a mixture of organic and inorganic to inorganic.The origins of hydrogen gas are complex and include organic sources,water radiolysis,water-rock(Fe^(2+)-containing minerals)reactions,and mantle-derived.The shales of Denglouku and Shahezi Formations,as source rocks,provide the premise for generation and occurrence of organic gas.Furthermore,the deep faults and fluid activities in Basement Formation control the generation and migration of mantle-derived gas.The discovery of a high content of H_(2)in study area not only reveals the organic and inorganic association of natural-gas generation,but also provides a scientific basis for the exploration of deep hydrogen-rich gas.展开更多
During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and...During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines,resulting in production reduction,shutdowns,and pressure build-ups.Consequently,a cascade of risks is prone to occur.To address this issue,this study focuses on the operational process of natural gas gathering and transmission pipelines,where a comprehensive framework is established.This framework includes theoretical models for pipeline temperature distribution,pipeline pressure distribution,multiphase flow within the pipeline,hydrate blockage,and numerical solution methods.By analyzing the influence of inlet temperature,inlet pressure,and terminal pressure on hydrate formation within the pipeline,the sensitivity patterns of hydrate blockage risks are derived.The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate,potentially mitigating pipeline blockage during natural gas transportation.Furthermore,an increase in inlet temperature and terminal pressure,and a decrease in inlet pressure,results in a displacement of the most probable location for hydrate blockage towards the terminal station.However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system,contradicting the operational goal of energy efficiency and reduction of energy consumption.Consequently,for high-pressure gathering pipelines,measures such as raising the inlet temperature or employing inhibitors,electrical heat tracing,and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation.Moreover,considering abnormal conditions such as gas well production and pipeline network shutdowns,which could potentially trigger hydrate formation,the installation of methanol injection connectors remains necessary to ensure production safety.展开更多
Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical char...Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents.展开更多
The natural gas heavy carbon isotope and high dryness coefficients genesis in Tabei uplift,Tarim Basin has been highly controversial.To investigate the generation mechanisms of natural gas in the Tabei Uplift.Natural ...The natural gas heavy carbon isotope and high dryness coefficients genesis in Tabei uplift,Tarim Basin has been highly controversial.To investigate the generation mechanisms of natural gas in the Tabei Uplift.Natural gas chemical composition,carbon isotopes were used to analyze the genesis of natural gas,source rock maturity,and basin modeling were conducted to reconstruct the natural gas generation process,and the influences of instantaneous and cumulative effects on natural gas properties was discussed.The results show that the dryness coefficients of natural gas range from 0.62 to 0.99(average:0.92),the methane contents range from 30.42%to 96.4%(average:85.10%),ethane contents from 0.43%to 15.58%(average:3.39%),propane contents from 0.11%to 11.43%(average:1.78%),and the methane carbon isotopes range from-47.30‰to-33.80‰(average:-36.96‰),ethane carbon isotopes range from-39.60‰to-33.20‰(average:-35.57‰),propane carbon isotopes range from-36.90‰to-28.50‰(average:-35.49‰).Compared with the actual regional thermal evolution of the source rock(Ro%range from 1.4%-1.7%),the natural gas exhibits excessively high dryness coefficients and heavy methane carbon isotope characteristics.The natural gas is primary cracking gas and sourced from marine typeⅡkerogen.The dryness coefficient,methane carbon isotopes,and source rock maturity gradually increases from the west to the east.Instantaneous effects and leakage led to the dry gas and relative heavy methane carbon isotopes generated at a low maturity level.The current natural gas in the Ordovician reservoirs was all generated during the Himalayan orogeny.Long period pause of the gas generation between the two hydrocarbon generation phases is the main cause for the instantaneous effects.展开更多
Blast furnace gas(BFG)is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation.However,the undesirable contaminants in BFG(especially H_(2)S)gene...Blast furnace gas(BFG)is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation.However,the undesirable contaminants in BFG(especially H_(2)S)generate harmful environmental emissions.The desulfurization of BFG is urgent for integrated steel plants due to the stringent ultra-low emission standards.Compared with other desulfurization materials,zeolite-based adsorbents represent a viable option with low costs and long service life.In this study,an ammonia-induced CuO modified 13X adsorbent(NH_(3)–CuO/13X)was prepared for H_(2)S removal from simulated BFG at low temperature.The XRD,H_(2)-TPR and TEM analysis proved that smaller CuO particles were formed and the dispersion of Cu on the surface of 13X zeolite was improved via the induction of ammonia.Evaluation on H_(2)S adsorption performance of the adsorbent was carried out using simulated BFG,and the results showed that NH_(3)–CuO/13X-3 has better breakthrough sulfur capacity,which was more than twice the sulfur capacity of CuO/13X.It is proposed that the enhanced desulfurization performance of NH_(3)–CuO/13X is attributed to an abundant pore of 13X,and combined action of 13X and CuO.This work provided an effective way to improve the sulfur capacity of zeolite-based adsorbents via impregnation method by ammonia induction.展开更多
Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart...Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart monitoring terminal,cloud storage/computing technology,and artificial intelligence,smart gas sensors represent the future of gassensing due to their merits of real-time multifunctional monitoring,earlywarning function,and intelligent and automated feature.Various electronicand optoelectronic gas sensors have been developed for high-performancesmart gas analysis.With the development of smart terminals and the maturityof integrated technology,flexible and wearable gas sensors play an increasingrole in gas analysis.This review highlights recent advances of smart gassensors in diverse applications.The structural components and fundamentalprinciples of electronic and optoelectronic gas sensors are described,andflexible and wearable gas sensor devices are highlighted.Moreover,sensorarray with artificial intelligence algorithms and smart gas sensors in“Internet of Things”paradigm are introduced.Finally,the challengesand perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.展开更多
In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-...In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture.The results demonstrated that the boundary of the gas transport zone was located in the region of fracture separation.The boundary of the gas storage area was located in the abrupt penetration zone.Also,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture entropy.The mathematical representation model of the dip effect in gas transport and storage areas was established.The criteria upon which the regional location of the gas transport area and gas storage area can be based were put forward.The cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as well.The research results could provide guidance for realising directional and accurate gas extraction.展开更多
Using the Bose-Fermi mapping method,we obtain the exact ground state wavefunction of one-dimensional(1D)Bose gas with the zero-range dipolar interaction in the strongly repulsive contact interaction limit.Its ground s...Using the Bose-Fermi mapping method,we obtain the exact ground state wavefunction of one-dimensional(1D)Bose gas with the zero-range dipolar interaction in the strongly repulsive contact interaction limit.Its ground state density distributions for both repulsive and attractive dipole interactions are exhibited.It is shown that in the case of the finite dipole interaction the density profiles do not change obviously with the increase of dipole interaction and display the typical shell structure of Tonks-Girardeau gases.As the repulsive dipole interaction is greatly strong,the density decreases at the center of the trap and displays a sunken valley.As the attractive dipole interaction increases,the density displays more oscillations and sharp peaks appear in the strong attraction limit,which mainly originate from the atoms occupying the low single particle levels.展开更多
Royal jelly(RJ)is rich in various nutrients with multiple health-promoting properties.This study aims to evaluate whether RJ can modulate related metabolite in the natural aging mice.Male C57BL/6J mice drank RJ soluti...Royal jelly(RJ)is rich in various nutrients with multiple health-promoting properties.This study aims to evaluate whether RJ can modulate related metabolite in the natural aging mice.Male C57BL/6J mice drank RJ solution daily for 9 months.Determination of serum lipids and pathological analysis exhibited that triglycerides,serum cholesterol,and low-density lipoprotein cholesterol were decreased by 31.15%,9.96%,and 22.58%,respectively,the morphology of brain nerve cells was also effectively recovered after RJ intervention.Lipidomic analysis showed that RJ could improve the levels of different kinds of lipids in aging mice brain,especially by increasing the content of antioxidant ether ester,and that the ratio of monounsaturated fatty acid to polyunsaturated fatty acid was up by 23.46%,which could alleviate oxidative stress.Moreover,the metabolism of glycerol phospholipids,glycerols,and fatty acids in aging mice could be regulated by RJ.RJ intervention can effectively improve lipid metabolism disorders caused by aging.展开更多
The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages i...The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.展开更多
This paper compares three methods for natural gas dehydration that are widely applied in industry：（1） absorption by triethylene glycol, （2） adsorption on solid desiccants and （3） condensation. A comparison is m...This paper compares three methods for natural gas dehydration that are widely applied in industry：（1） absorption by triethylene glycol, （2） adsorption on solid desiccants and （3） condensation. A comparison is made according to their energy demand and suitability for use. The energy calculations are performed on a model where 105 Nm3/h water saturated natural gas is processed at 30 °C. The pressure of the gas varies from 7 to 20 MPa. The required outlet concentration of water in natural gas is equivalent to the dew point temperature of -10 °C at gas pressure of 4 MPa.展开更多
Gas compressibility factor （z-Factor） is one of the most important parameters in upstream and downstream calculations of petroleum industries.The importance of z-Factor cannot be overemphasized in oil and gas engine...Gas compressibility factor （z-Factor） is one of the most important parameters in upstream and downstream calculations of petroleum industries.The importance of z-Factor cannot be overemphasized in oil and gas engineering calculations.The experimental measurements,Equations of State （EoS） and empirical correlations are the most common sources of z-Factor calculations.There are more than twenty correlations available with two variables for calculating the z-Factor from fitting in an EoS or just through fitting techniques.However,these correlations are too complex,which require initial value and more complicated and longer computations or have magnitude error.The purpose of this study is to develop a new accurate correlation to rapidly estimate z-Factor.Result of this correlation is compared with large scale of database and experimental data also.Proposed correlation has 1.660 of Absolute Percent Relative Error （EABS） versus Standing and Katz chart and has also 3.221 of EABS versus experimental data.The output of this correlation can be directly assumed or be used as an initial value of other implicit correlations.This correlation is valid for gas coefficient of isothermal compressibility （cg） calculations also.展开更多
Membrane technology is becoming more important for CO,_ separation from natural gas in the new era due to its process simplicity, relative ease of operation and control, compact, and easy to scale up as compared with ...Membrane technology is becoming more important for CO,_ separation from natural gas in the new era due to its process simplicity, relative ease of operation and control, compact, and easy to scale up as compared with conventional processes. Conventional processes such as absorption and adsorption for CO2 separation from natural gas are generally more energy demanding and costly for both operation and maintenance. Polymeric membranes are the current commercial membranes used for CO2 separation from natural gas. However, polymeric membranes possess drawbacks such as low permeability and selectivity, plasticization at high temperatures, as well as insufficient thermal and chemical stability. The shortcomings of commercial polymeric membranes have motivated researchers to opt for other alternatives, especially inorganic membranes due to their higher thermal stability, good chemical resistance to solvents, high mechanical strength and long lifetime. Surface modifications can be utilized in inorganic membranes to further enhance the selectivity, permeability or catalytic activities of the membrane. This paper is to provide a comprehensive review on gas separation, comparing membrane technology with other conventional methods of recovering CO2 from natural gas, challenges of current commercial polymeric membranes and inorganic membranes for CO2 removal and membrane surface modification for improved selectivity.展开更多
This paper establishes a risk assessment index system for the natural gas industrial chain. China＇s natural gas industrial chain is entering a stage of rapid growth. In order to guarantee healthy development of the n...This paper establishes a risk assessment index system for the natural gas industrial chain. China＇s natural gas industrial chain is entering a stage of rapid growth. In order to guarantee healthy development of the natural gas industrial chain, it is urgent to establish a risk alert system, which is based on a risk assessment index system. First of all, the risks of the natural gas industrial chain are defined in the paper; then the risk factors are analyzed according to the present status of the natural gas industrial chain, and five categories of risk factors are summarized： resource risk, transport risk, marketing risk, risk of unbalanced chain links, and environment risk. The paper presents the principles of the risk assessment index system. The natural gas industrial chain risk assessment index system is established with four levels and forty-six risk indices.展开更多
Natural gas hydrate(NGH)has been widely considered as an alternative to conventional oil and gas resources in the future energy resource supply since Trofimuk’s first resource assessment in 1973.At least 29 global es...Natural gas hydrate(NGH)has been widely considered as an alternative to conventional oil and gas resources in the future energy resource supply since Trofimuk’s first resource assessment in 1973.At least 29 global estimates have been published from various studies so far,among which 24 estimates are greater than the total conventional gas resources.If drawn in chronological order,the 29 historical resource estimates show a clear downward trend,reflecting the changes in our perception with respect to its resource potential with increasing our knowledge on the NGH with time.A time series of the 29 estimates was used to establish a statistical model for predict the future trend.The model produces an expected resource value of 41.46×1012 m3 at the year of 2050.The statistical trend projected future gas hydrate resource is only about 10%of total natural gas resource in conventional reservoir,consistent with estimates of global technically recoverable resources(TRR)in gas hydrate from Monte Carlo technique based on volumetric and material balance approaches.Considering the technical challenges and high cost in commercial production and the lack of competitive advantages compared with rapid growing unconventional and renewable resources,only those on the very top of the gas hydrate resource pyramid will be added to future energy supply.It is unlikely that the NGH will be the major energy source in the future.展开更多
The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural gas.The swirling separation of natural gas in the convergent-divergent nozzle was numerical...The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural gas.The swirling separation of natural gas in the convergent-divergent nozzle was numerically simulated based on a new design which incorporates a central body. Axial distribution of the main parameters of gas flow was investigated,while the basic parameters of gas flow were obtained as functions of radius at the nozzle exit.The effect of the nozzle geometry on the swirling separation was analyzed.The numerical results show that water and heavy hydrocarbons can be condensed and separated from natural gas under the combined effect of the low temperature（-80℃） and the centrifugal field（482,400g,g is the acceleration of gravity）.The gas dynamic parameters are uniformly distributed correspondingly in the radial central region of the channel,for example the distribution range of the static temperature and the centrifugal acceleration are from -80 to -55℃and 220,000g to 500,000g,respectively,which would create good conditions for the cyclone separation of the liquids.However,high gradients of gas dynamic parameters near the channel walls may impair the process of separation.The geometry of the nozzle has a great influence on the separation performance. Increasing the nozzle convergent angle can improve the separation efficiency.The swirling natural gas can be well separated when the divergent angle takes values from 4°to 12°in the convergent-divergent nozzle.展开更多
CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for C...CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO2 and other gases. However. rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO2 capture. In this paper, the key problems in CO2 capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas （CO2/CH4 system）, the bottleneck is how to enhance the selectivity of CO2 hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO2 separation from shifted synthesis gas, flue gas and sour natural gas or biogas.展开更多
基金Supported by the National Natural Science Foundation of China(No.51909154)Shanghai Engineering Research Center of Ship Intelligent Maintenance and Energy Efficiency(No.20DZ2252300).
文摘Using natural gas(NG)as the primary fuel helps alleviate the fossil fuel crisis while reducing engine soot and nitrogen oxide(NO_(X))emissions.In this paper,the influences of a novel split injection concept on an NG high pressure direct injection(HPDI)engine are examined.Four typical split injection strategies,namely split pre-injection of pilot diesel(PD)and NG,split post-injection of PD and NG,split pre-injection of NG,and split post-injection of PD,were developed to investigate the influences on combustion and emissions.Results revealed that split pre injection of NG enhanced the atomization of PD,whereas the split post-injection of NG lowered the temperature in the core region of the PD spray,resulting in the deterioration of combustion.The effect of the split injection strategy on indicated thermal efficiency exceeded 7.5%.Split pre-injection was favorable to enhancing thermal efficiency,whereas split post-injection was not.Ignition delay,combustion duration,and premixed combustion time proportion were affected by injection strategies by 3.8%,50%,and 19.7%,respectively.Split pre-injection increased CH_(4) emission in the exhaust.Split post-injection,especially split post-injection of PD and NG,reduced the unburned CH_(4) emission by approximately 30%.When the split post-injection ratio was less than 30%,the trade-off between NO_(X) and soot was interrupted.The distribution range of hydroxyl radicals was expanded by pre-injection,and NO_(X) was generated in the region where the NG jet hit the wall.This paper provides valuable insights into the optimization of HPDI injection parameters.
文摘In the mid-21st century,natural gas will enter its golden age,and the era of natural gas is arriving.This paper reviews the development stages of global natural gas industry and the enlightenment of American shale gas revolution,summarizes the development history and achievements of the natural gas industry in China,analyzes the status and challenges of natural gas in the green and low-carbon energy transition,and puts forward the natural gas industry development strategies under carbon neutral target in China.The natural gas industry in China has experienced three periods:start,growth,and leap forward.At present,China has become the fourth largest natural gas producer and third largest natural gas consumer in the world,and has made great achievements in natural gas exploration and development theory and technology,providing important support for the growth of production and reserves.China has set its goal of carbon neutrality to promote green and sustainable development,which brings opportunities and challenges for natural gas industry.Natural gas has significant low-carbon advantages,and gas-electric peak shaving boosts new energy development;the difficulty and cost of development are more prominent.For the national energy security and harmonious development between economy and ecology under the carbon neutral goal,based on the principle of"comprehensive planning,technological innovation,multi-energy complementarity,diversified integration,flexibility and efficiency,optimization and upgrading",the construction of the production-supplystorage-marketing system has to be improved so as to boost the development of the natural gas industry.First,it is necessary to strengthen efforts in the exploration and development of natural gas,making projects and arrangement in key exploration and development areas,meanwhile,it is urgent to make breakthroughs in key science theories and technologies,so as to increase reserve and production.Second,it should promote green and innovative development of the natural gas by developing new techniques,expanding new fields and integrating with new energy.Third,there is a demand to realize transformation and upgrading of the supply and demand structure of natural gas by strengthening the layout of pipeline gas,liquefied natural gas and the construction of underground gas storage,establishing reserve system for improving abilities of emergency response and adjustment,raising the proportion of natural gas in the primary energy consumption and contributing to the transformation of energy consumption structure,realizing low-carbon resources utilization and clean energy consumption.
基金This work was supported by the National Natural Science Foundation of China(51874332,51991363)the CNPC's Major Science and Technology Projects(ZD2019-184-003)+1 种基金the Fundamental Research Funds for Central Universities(20CX05008A)“14th Five-Year plan”forward-looking basic major science and technology project of CNPC(2021DJ4901).
文摘Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.
基金supported by the National Natural Science Foundation of China(Grant No.42072168)the National Key R&D Program of China(Grant No.2019YFC0605405)the Fundamental Research Funds for the Central Universities(Grant No.2023ZKPYDC07)。
文摘The different reservoirs in deep Songliao Basin have non-homogeneous lithologies and include multiple layers with a high content of hydrogen gas.The gas composition and stable isotope characteristics vary significantly,but the origin analysis of different gas types has previously been weak.Based on the geochemical parameters of gas samples from different depths and the analysis of geological settings,this research covers the diverse origins of natural gas in different strata.The gas components are mainly methane with a small amount of C_(2+),and non-hydrocarbon gases,including nitrogen(N_(2)),hydrogen(H_(2)),carbon dioxide(CO_(2)),and helium(He).At greater depth,the carbon isotope of methane becomes heavier,and the hydrogen isotope points to a lacustrine sedimentary environment.With increasing depth,the origins of N_(2)and CO_(2)change gradually from a mixture of organic and inorganic to inorganic.The origins of hydrogen gas are complex and include organic sources,water radiolysis,water-rock(Fe^(2+)-containing minerals)reactions,and mantle-derived.The shales of Denglouku and Shahezi Formations,as source rocks,provide the premise for generation and occurrence of organic gas.Furthermore,the deep faults and fluid activities in Basement Formation control the generation and migration of mantle-derived gas.The discovery of a high content of H_(2)in study area not only reveals the organic and inorganic association of natural-gas generation,but also provides a scientific basis for the exploration of deep hydrogen-rich gas.
基金supported by 111 Project (No.D21025)Open Fund Project of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Nos.PLN2021-01,PLN2021-02,PLN2021-03)+2 种基金High-end Foreign Expert Introduction Program (No.G2021036005L)National Key Research and Development Program (No.2021YFC2800903)National Natural Science Foundation of China (No.U20B6005-05)。
文摘During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines,resulting in production reduction,shutdowns,and pressure build-ups.Consequently,a cascade of risks is prone to occur.To address this issue,this study focuses on the operational process of natural gas gathering and transmission pipelines,where a comprehensive framework is established.This framework includes theoretical models for pipeline temperature distribution,pipeline pressure distribution,multiphase flow within the pipeline,hydrate blockage,and numerical solution methods.By analyzing the influence of inlet temperature,inlet pressure,and terminal pressure on hydrate formation within the pipeline,the sensitivity patterns of hydrate blockage risks are derived.The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate,potentially mitigating pipeline blockage during natural gas transportation.Furthermore,an increase in inlet temperature and terminal pressure,and a decrease in inlet pressure,results in a displacement of the most probable location for hydrate blockage towards the terminal station.However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system,contradicting the operational goal of energy efficiency and reduction of energy consumption.Consequently,for high-pressure gathering pipelines,measures such as raising the inlet temperature or employing inhibitors,electrical heat tracing,and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation.Moreover,considering abnormal conditions such as gas well production and pipeline network shutdowns,which could potentially trigger hydrate formation,the installation of methanol injection connectors remains necessary to ensure production safety.
基金Supported by the National Natural Science Foundation of China(42172149,U2244209)Sinopec Science and Technology Research Project(P23230,P22132)。
文摘Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents.
基金financially funded by National Natural Science Foundation of China(Grant Nos.4182100242172160)+1 种基金PetroChina(Grant No.ZD 2019-183-002)National Natural Science Foundation of China(Grant No.42202142)。
文摘The natural gas heavy carbon isotope and high dryness coefficients genesis in Tabei uplift,Tarim Basin has been highly controversial.To investigate the generation mechanisms of natural gas in the Tabei Uplift.Natural gas chemical composition,carbon isotopes were used to analyze the genesis of natural gas,source rock maturity,and basin modeling were conducted to reconstruct the natural gas generation process,and the influences of instantaneous and cumulative effects on natural gas properties was discussed.The results show that the dryness coefficients of natural gas range from 0.62 to 0.99(average:0.92),the methane contents range from 30.42%to 96.4%(average:85.10%),ethane contents from 0.43%to 15.58%(average:3.39%),propane contents from 0.11%to 11.43%(average:1.78%),and the methane carbon isotopes range from-47.30‰to-33.80‰(average:-36.96‰),ethane carbon isotopes range from-39.60‰to-33.20‰(average:-35.57‰),propane carbon isotopes range from-36.90‰to-28.50‰(average:-35.49‰).Compared with the actual regional thermal evolution of the source rock(Ro%range from 1.4%-1.7%),the natural gas exhibits excessively high dryness coefficients and heavy methane carbon isotope characteristics.The natural gas is primary cracking gas and sourced from marine typeⅡkerogen.The dryness coefficient,methane carbon isotopes,and source rock maturity gradually increases from the west to the east.Instantaneous effects and leakage led to the dry gas and relative heavy methane carbon isotopes generated at a low maturity level.The current natural gas in the Ordovician reservoirs was all generated during the Himalayan orogeny.Long period pause of the gas generation between the two hydrocarbon generation phases is the main cause for the instantaneous effects.
基金financially supported by National Natural Science Foundation of China(Grant.22076189)National Key Research and Development Program of China(No.2023YFC3707003)the Joint Fund of Yulin University and Dalian National Laboratory for Clean Energy(Grant.YLU-DNL Fund 2022003).
文摘Blast furnace gas(BFG)is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation.However,the undesirable contaminants in BFG(especially H_(2)S)generate harmful environmental emissions.The desulfurization of BFG is urgent for integrated steel plants due to the stringent ultra-low emission standards.Compared with other desulfurization materials,zeolite-based adsorbents represent a viable option with low costs and long service life.In this study,an ammonia-induced CuO modified 13X adsorbent(NH_(3)–CuO/13X)was prepared for H_(2)S removal from simulated BFG at low temperature.The XRD,H_(2)-TPR and TEM analysis proved that smaller CuO particles were formed and the dispersion of Cu on the surface of 13X zeolite was improved via the induction of ammonia.Evaluation on H_(2)S adsorption performance of the adsorbent was carried out using simulated BFG,and the results showed that NH_(3)–CuO/13X-3 has better breakthrough sulfur capacity,which was more than twice the sulfur capacity of CuO/13X.It is proposed that the enhanced desulfurization performance of NH_(3)–CuO/13X is attributed to an abundant pore of 13X,and combined action of 13X and CuO.This work provided an effective way to improve the sulfur capacity of zeolite-based adsorbents via impregnation method by ammonia induction.
基金supported by the National Natural Science Foundation of China(No.22376159)the Fundamental Research Funds for the Central Universities.
文摘Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart monitoring terminal,cloud storage/computing technology,and artificial intelligence,smart gas sensors represent the future of gassensing due to their merits of real-time multifunctional monitoring,earlywarning function,and intelligent and automated feature.Various electronicand optoelectronic gas sensors have been developed for high-performancesmart gas analysis.With the development of smart terminals and the maturityof integrated technology,flexible and wearable gas sensors play an increasingrole in gas analysis.This review highlights recent advances of smart gassensors in diverse applications.The structural components and fundamentalprinciples of electronic and optoelectronic gas sensors are described,andflexible and wearable gas sensor devices are highlighted.Moreover,sensorarray with artificial intelligence algorithms and smart gas sensors in“Internet of Things”paradigm are introduced.Finally,the challengesand perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.
基金supported by the National Natural Science Foundation of China(No.5217-4205)Shaanxi Provincial Outstanding Youth Science Fund Project(No.2023-JC-JQ-40)+4 种基金National Key Research and Development Project(No.2023YFC3009004)Key Project of Shaanxi Provincial Department of Education(No.22JY040)Xinjiang Uygur Autonomous Region Key Research and Development Task Special Project(No.2022B01034-3)Key Laboratory of Green Coal Mining in Xinjiang,Ministry of Education(No.KLXGY-KA2404)Shaanxi Provincial Key Research and Development Task General Project(No.2024GX–YBXM-490)。
文摘In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture.The results demonstrated that the boundary of the gas transport zone was located in the region of fracture separation.The boundary of the gas storage area was located in the abrupt penetration zone.Also,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture entropy.The mathematical representation model of the dip effect in gas transport and storage areas was established.The criteria upon which the regional location of the gas transport area and gas storage area can be based were put forward.The cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as well.The research results could provide guidance for realising directional and accurate gas extraction.
基金Project supported by the National Natural Science Foundation of China(Grant No.11174026)。
文摘Using the Bose-Fermi mapping method,we obtain the exact ground state wavefunction of one-dimensional(1D)Bose gas with the zero-range dipolar interaction in the strongly repulsive contact interaction limit.Its ground state density distributions for both repulsive and attractive dipole interactions are exhibited.It is shown that in the case of the finite dipole interaction the density profiles do not change obviously with the increase of dipole interaction and display the typical shell structure of Tonks-Girardeau gases.As the repulsive dipole interaction is greatly strong,the density decreases at the center of the trap and displays a sunken valley.As the attractive dipole interaction increases,the density displays more oscillations and sharp peaks appear in the strong attraction limit,which mainly originate from the atoms occupying the low single particle levels.
基金supported by the Science and Technology Department of Jiangxi Province(20212AEI91010)National Natural Science Foundation of China(31772067)+1 种基金Jiangxi Agriculture Research System(JXARS-14)Research Project of State Key Laboratory of Food Science and Technology(SKFL-ZZB-2)。
文摘Royal jelly(RJ)is rich in various nutrients with multiple health-promoting properties.This study aims to evaluate whether RJ can modulate related metabolite in the natural aging mice.Male C57BL/6J mice drank RJ solution daily for 9 months.Determination of serum lipids and pathological analysis exhibited that triglycerides,serum cholesterol,and low-density lipoprotein cholesterol were decreased by 31.15%,9.96%,and 22.58%,respectively,the morphology of brain nerve cells was also effectively recovered after RJ intervention.Lipidomic analysis showed that RJ could improve the levels of different kinds of lipids in aging mice brain,especially by increasing the content of antioxidant ether ester,and that the ratio of monounsaturated fatty acid to polyunsaturated fatty acid was up by 23.46%,which could alleviate oxidative stress.Moreover,the metabolism of glycerol phospholipids,glycerols,and fatty acids in aging mice could be regulated by RJ.RJ intervention can effectively improve lipid metabolism disorders caused by aging.
基金support from Subtopics of National Science and Technology Major Project(2011ZX05026-004-03)the National Natural Science Foundation of China (51104167)
文摘The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.
基金supported by the Inovation and Optimalization of Technologies for Natural Gas Dehydration(No.FR-TI1/173)
文摘This paper compares three methods for natural gas dehydration that are widely applied in industry：（1） absorption by triethylene glycol, （2） adsorption on solid desiccants and （3） condensation. A comparison is made according to their energy demand and suitability for use. The energy calculations are performed on a model where 105 Nm3/h water saturated natural gas is processed at 30 °C. The pressure of the gas varies from 7 to 20 MPa. The required outlet concentration of water in natural gas is equivalent to the dew point temperature of -10 °C at gas pressure of 4 MPa.
基金supported by Research Institute of Petroleum Industry-Kermanshah Campus
文摘Gas compressibility factor （z-Factor） is one of the most important parameters in upstream and downstream calculations of petroleum industries.The importance of z-Factor cannot be overemphasized in oil and gas engineering calculations.The experimental measurements,Equations of State （EoS） and empirical correlations are the most common sources of z-Factor calculations.There are more than twenty correlations available with two variables for calculating the z-Factor from fitting in an EoS or just through fitting techniques.However,these correlations are too complex,which require initial value and more complicated and longer computations or have magnitude error.The purpose of this study is to develop a new accurate correlation to rapidly estimate z-Factor.Result of this correlation is compared with large scale of database and experimental data also.Proposed correlation has 1.660 of Absolute Percent Relative Error （EABS） versus Standing and Katz chart and has also 3.221 of EABS versus experimental data.The output of this correlation can be directly assumed or be used as an initial value of other implicit correlations.This correlation is valid for gas coefficient of isothermal compressibility （cg） calculations also.
基金supported by the Ministry of Higher Education Malaysia through Long Term Research Grant Scheme (A/C Number 2110226-113-00)
文摘Membrane technology is becoming more important for CO,_ separation from natural gas in the new era due to its process simplicity, relative ease of operation and control, compact, and easy to scale up as compared with conventional processes. Conventional processes such as absorption and adsorption for CO2 separation from natural gas are generally more energy demanding and costly for both operation and maintenance. Polymeric membranes are the current commercial membranes used for CO2 separation from natural gas. However, polymeric membranes possess drawbacks such as low permeability and selectivity, plasticization at high temperatures, as well as insufficient thermal and chemical stability. The shortcomings of commercial polymeric membranes have motivated researchers to opt for other alternatives, especially inorganic membranes due to their higher thermal stability, good chemical resistance to solvents, high mechanical strength and long lifetime. Surface modifications can be utilized in inorganic membranes to further enhance the selectivity, permeability or catalytic activities of the membrane. This paper is to provide a comprehensive review on gas separation, comparing membrane technology with other conventional methods of recovering CO2 from natural gas, challenges of current commercial polymeric membranes and inorganic membranes for CO2 removal and membrane surface modification for improved selectivity.
基金This research is supported by CNPC Innovation Foundation.
文摘This paper establishes a risk assessment index system for the natural gas industrial chain. China＇s natural gas industrial chain is entering a stage of rapid growth. In order to guarantee healthy development of the natural gas industrial chain, it is urgent to establish a risk alert system, which is based on a risk assessment index system. First of all, the risks of the natural gas industrial chain are defined in the paper; then the risk factors are analyzed according to the present status of the natural gas industrial chain, and five categories of risk factors are summarized： resource risk, transport risk, marketing risk, risk of unbalanced chain links, and environment risk. The paper presents the principles of the risk assessment index system. The natural gas industrial chain risk assessment index system is established with four levels and forty-six risk indices.
基金This research was financially supported by the CAS consultation project(Grant number-2019-ZW11-Z-035)the National Basic Research Program of China(973)(Projects:2006CB202300,2011CB201100)+1 种基金China High-Tech R&D(863)Program Project(2013AA092600)We would like to thank Gao Deli,Academician of Chinese Academy of Sciences,for his comments and recommendation in publishing this paper in Petroleum Science.
文摘Natural gas hydrate(NGH)has been widely considered as an alternative to conventional oil and gas resources in the future energy resource supply since Trofimuk’s first resource assessment in 1973.At least 29 global estimates have been published from various studies so far,among which 24 estimates are greater than the total conventional gas resources.If drawn in chronological order,the 29 historical resource estimates show a clear downward trend,reflecting the changes in our perception with respect to its resource potential with increasing our knowledge on the NGH with time.A time series of the 29 estimates was used to establish a statistical model for predict the future trend.The model produces an expected resource value of 41.46×1012 m3 at the year of 2050.The statistical trend projected future gas hydrate resource is only about 10%of total natural gas resource in conventional reservoir,consistent with estimates of global technically recoverable resources(TRR)in gas hydrate from Monte Carlo technique based on volumetric and material balance approaches.Considering the technical challenges and high cost in commercial production and the lack of competitive advantages compared with rapid growing unconventional and renewable resources,only those on the very top of the gas hydrate resource pyramid will be added to future energy supply.It is unlikely that the NGH will be the major energy source in the future.
基金supported by the National High Technology Research and Development Program of China("863 program",No.2007AA09Z301) the National Major Science&Technology Specific Projects(No.2008ZX05017-004)
文摘The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural gas.The swirling separation of natural gas in the convergent-divergent nozzle was numerically simulated based on a new design which incorporates a central body. Axial distribution of the main parameters of gas flow was investigated,while the basic parameters of gas flow were obtained as functions of radius at the nozzle exit.The effect of the nozzle geometry on the swirling separation was analyzed.The numerical results show that water and heavy hydrocarbons can be condensed and separated from natural gas under the combined effect of the low temperature（-80℃） and the centrifugal field（482,400g,g is the acceleration of gravity）.The gas dynamic parameters are uniformly distributed correspondingly in the radial central region of the channel,for example the distribution range of the static temperature and the centrifugal acceleration are from -80 to -55℃and 220,000g to 500,000g,respectively,which would create good conditions for the cyclone separation of the liquids.However,high gradients of gas dynamic parameters near the channel walls may impair the process of separation.The geometry of the nozzle has a great influence on the separation performance. Increasing the nozzle convergent angle can improve the separation efficiency.The swirling natural gas can be well separated when the divergent angle takes values from 4°to 12°in the convergent-divergent nozzle.
基金the National Natural Science Foundation of China(Grant No.51176051 and 51106054)the National Basic Research Program of China(973 Program,No.2009CB219504-03)
文摘CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO2 and other gases. However. rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO2 capture. In this paper, the key problems in CO2 capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas （CO2/CH4 system）, the bottleneck is how to enhance the selectivity of CO2 hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO2 separation from shifted synthesis gas, flue gas and sour natural gas or biogas.
