最新刊期
期 4 ， 2023
- 摘要：Based on the phenomenon that methane can be activated at low temperature by co-reacting with other hydrocarbon raw materials at 400 ℃ to 600 ℃, different activation mechanisms and reaction paths of methane during this process were reviewed.The characteristics of different types of reactions involving methane after low temperature activation, such as heavy oil modification reaction, olefin hydrogenation reaction, low carbon hydrocarbon aromatization reaction and deoxyaromatization reaction of oxygencontaining compounds, as well as the effects of co-reaction additives and catalytic effects of catalysts, were summarized. It is found that, although the activation mechanism and participation path of methane in the co-reaction process with other raw materials are different, it can be considered that methane is activated at low temperature under the promotion of other macromolecular hydrocarbons and participates in related reactions, playing the role of hydrogen supply, carburization and optimization of product distribution. In particular, in the aromatization process in which methane is involved, the participation of methane can improve product distribution and selectivity of methyl side chain products, etc., which can provide a good research basis for the development of low-cost utilization technology of methane.关键词：methane conversion;low-temperature activation;reaction mechanism;catalyst
- 15
- |
- 65
- |
- 0
发布时间：2023-08-31 - 摘要：The proportion of natural gas is increasing in the energy structure of China. Methane, the main component of natural gas,produces large amounts of CO and CO2 in the combustion process. Chemical-looping combustion technology of methane is one of the important technologies for CO2 capture, with the advantages of energy cascade utilization and NOx avoidance. While improving energy utilization rate, high purity CO2 can be obtained, which is beneficial to the subsequent storage and transformation and utilization, and is of great significance to the implementation of the “double carbon” strategy of our country. The main factor affecting the chemicallooping combustion technology is oxygen carrier, so the choice of oxygen carrier is particularly important. The basic principle and characteristics of chemical-looping combustion technology were presented, and the research progress of nickel base, copper base, iron base, manganese base, composite metal and non-metallic oxygen carrier in chemical-looping combustion with methane as fuel was summarized. It is found that the reaction performance of oxygen carrier is mainly affected by its oxygen carrying capacity, reactivity and sintering resistance. At the same time, the future development prospect of oxygen carrier in chemical-looping combustion technology of methane is prospected.关键词：chemical-looping combustion;methane;oxygen carrier;CO2 capture
- 9
- |
- 66
- |
- 0
发布时间：2023-08-31 - 摘要：Direct synthesis of dimethyl carbonate（DMC） from carbon dioxide（CO2） and methanol（CH3OH） can yield chemicals with high added value and mitigate the greenhouse effect.Due to thermodynamic limitations,the equilibrium conversion rate of this reaction is low.The introduction of 2-cyanopyridine as the dehydrating agent can make the reaction proceed in the direction of DMC to a greater extent.In-doped CeO2 catalyst（InxCeO2,x is the mole ratio of In to Ce） was prepared by coprecipitation method,and the effect of In doping on the catalytic activity of CO2 and methanol synthesis of DMC was investigated.The catalytic activity evaluation results show that the time and space yield of In0.01CeO2 catalyst prepared by coprecipitation method is 88.81 mmol/（g·h）（the yield of DMC catalyzed by 1 g catalyst within 1 h is 88.81 mmol,the same as below）,which is higher than that of CeO2 catalyst（49.83 mmol/g·h）.The crystal structure,specific surface area and surface composition of the catalyst were analyzed by XRD,BET and XPS.The characterization analysis confirmed that In doping into CeO2 lattice significantly increased the relative content of oxygen vacancies on the catalytic surface,resulting in an increase in the number of oxygen vacancies,which was conducive to the improvement of catalytic activity.When x is greater than 0.01,excess In will adhere to the surface of the catalyst and block the pore channel,resulting in the reduction of CeO2 content on the surface and specific surface area of the catalyst,and thus resulting in the reduction of the number of oxygen vacancies,and thus the catalytic activity of the catalyst.关键词：dimethyl carbonate;CO2;methanol;CeO2;In doping;oxygen vacancies
- 11
- |
- 87
- |
- 0
发布时间：2023-08-31 - 摘要：In the reverse water-gas shift（RWGS） reaction,the Cu oxide catalyst is easily deactivated at high temperature,but the transition metal carbide has the function of dispersing and stabilizing Cu particles.Cu/β-Mo2C catalysts with 1% and 3% Cu loads（mass fraction,the same as below） were synthesized using ammonium heptadolybdate（AMT）,hexamethyltetramine（HMT） and copper nitrate as materials by one-step temperature programmed carbonization method.The catalysts were characterized by XRD,H2-TPR,SEM and HRTEM.The results show that the addition of Cu directly weakens the characteristic diffraction peak of β-Mo2C,indicating strong interaction between the metal and the carrier.The low Cu loads was uniformly dispersed as 5 nm nanoparticles on β-Mo2C carrier with more active centers.The CO2 conversion rate and CO selectivity of 1%Cu/β-Mo2C catalyst at 600℃ are 51.00% and100%,respectively.The apparent activation energy is 24.69 kJ/mol,lower than 3%Cu/β-Mo2C,showing good activity and stability.It has been confirmed that 1%Cu/β-Mo2C has good catalytic performance and is a potential high efficiency catalyst for RWGS reaction.关键词：temperature-programmed carbonization;molybdenum carbide;Cu nanoparticle;reverse water-gas shift reaction
- 4
- |
- 59
- |
- 0
发布时间：2023-08-31 - 摘要：The pyrolysis or depolymerization of lignin can obtain lignin-derived phenols such as phenol, methoxyphenol and guaiacol.These lignin-derived phenols can be converted into liquid fuels after further hydrodeoxygenation（HDO） reaction. Aiming at the HDO reaction of lignin-derived phenols, the reaction mechanisms under liquid phase and vapor phase conditions were compared and analyzed, and the influences of reaction conditions on the reaction mechanisms were summarized firstly. Then the catalytic performances of noble metal, non-precious metal and bimetallic catalysts in vapor phase HDO reaction were reviewed. Finally, it is pointed out that Fe-based noble metal catalysts have good development potential in vapor phase hydrodeoxygenation.关键词：lignin;phenols;vapor phase hydrodeoxygenation;reaction mechanism;metal catalysts
- 4
- |
- 68
- |
- 0
发布时间：2023-08-31 - 摘要：As a typical municipal solid waste, the scrap tyres are difficult to clean due to their acid, alkali and biological resistance.The purpose of this paper is to study the pyrolysis mechanism of scrap tyres and the characteristics of pyrolysis oil components, so as to realize the resource utilization of the scrap tyres. The degradation characteristics of scrap tyres at different heating rates（5 ℃/min,10 ℃/min, 15 ℃/min and 20 ℃/min） were systematically investigated using thermogravimetric analysis（TGA）. The results show that the pyrolysis process of the scrap tyres mainly occurres in the temperature range of 200 ℃ to 500 ℃, and the mass loss curves（TG curves） and mass loss rate curves（DTG curves） gradually shift toward the higher temperature zone with the increase of heating rate.Three iso-conversion methods（Kissinger-Akahira-Sunose（KAS） model, Ozawa-Flynn-Wall（OFW） model and Friedman（FM） model）were used for kinetic analyses of the mass loss data, for which the apparent activation energies（Ea） are obtained to be in the ranges of 148 kJ/mol to 221 kJ/mol, 150 kJ/mol to 221 kJ/mol and 156 kJ/mol to 232 kJ/mol, respectively. Ea and pre-exponential factor（A）tend to increase and then decrease with the increase of the conversion rate. Then, the thermodynamic parameters（enthalpy change（ΔH）, Gibbs free energy change（ΔG） and entropy change（ΔS）） at different conversion rates were calculated by the OFW model. The calculation results indicate that ΔS and ΔH increase gradually with the increase of conversion rate until the conversion rate reached 0.9,and the opposite trend is observed for the change of the corresponding ΔG. In general, the effect of heating rate on the thermodynamic parameters is not obvious. In addition, the pyrolysis oil derived from the scrap tyre pyrolysis at 500 ℃ was analyzed by gas chromatography-mass spectrometry（GC-MS）, and the results exhibite that the content of D-limonene is up to 62.42%, which has a good utilization prospect. The results have a certain guiding significance for the resource utilization of scrap tyres and the optimization of pyrolysis technology.关键词：scrap tyres;pyrolysis;activation energy;kinetics;thermodynamics;pyrolysis oil
- 7
- |
- 60
- |
- 0
发布时间：2023-08-31 - 摘要：Low-carbon revolution will become an important channel for sustainable development in addressing the climate change.Deep coupling of low-cost renewable energy power generation with technologies such as hydrogen energy and carbon capture is an important direction in future energy technology revolution and industrial development. Green and low-carbon development has become the theme of the future. By building the development pattern of hydrogen-electric coupling industry, we can give full play to the exemplary role of clean energy in green and low-carbon upgrading industrial, as well as its main role in the innovation and application of low-carbon technologies. The urgent needs of structural optimization of energy and industrial low-carbon economic transformation in recent years were summarized. The new low-carbon development mode of “industry + green hydrogen” was analyzed. The feasible development direction of energy-carrying green hydrogen chemical industry was discussed in order to facilitate the supply of low-carbon, even zero-carbon products. And the application of low-carbon technology in the establishment of zero-carbon park was prospected furtherly.关键词：rennewable energy;low-carbon development;green methanol;green ammonia;zero-carbon park
- 10
- |
- 315
- |
- 0
发布时间：2023-08-31 - 摘要：In the process of metal oxide desulfurization,partial hydrogen sulfide（H2S） is commonly converted into carbonyl sulfide（COS）,and COS has similar harm to H2S and is more difficulty to remove.ZnO/MCM-41 coal gas desulfurizer（hereinafter referred to as“desulfurizer”） with good desulfurization performance was prepared by sol-gel method.The formation behavior of COS in desulfurization process was studied on a fixed bed device,and the method of inhibiting COS formation by modification of Co additive was proposed.Then the phase composition and structure of desulfurizer were analyzed by XRD,XPS and other characterization methods.By comparing COS formation behaviors in different desulfurization atmospheres,it is found that COS mainly derives from the reaction of CO/CO2 with H2S,and ZnS catalyzes the reaction of CO2 with H2S.Meanwhile,there is no synergistic effect between the reaction of CO-H2S and CO2-H2S.The presence of H2 inhibits the formation of COS.When the Co additive with the mass fraction of Co of 1%,3%and 5%are added to the desulfurizer,the COS production in the desulfurization process can be reduced by 69.0%,94.9%and 98.4%,which is mainly related to the catalytic effect of additive Co on COS hydrogenation.In addition,the sulfur capacity of desulfurizer is increased by 0.32%by adding the Co additive with 3%Co mass fraction.关键词：COS;ZnO/MCM-41;high temperature coal gas;desulfurizer;hydrodesulfurization
- 8
- |
- 78
- |
- 0
发布时间：2023-08-31 - 摘要：Catalytic combustion is one of the effective methods to convert and utilize low concentration gas at present.In order to investigate the effect of preparation technology on the catalytic performance of Co-Cu composite oxide catalyst for low concentration gas combustion,the Co-Cu composite catalyst was prepared by sol-gel method and coprecipitation method respectively and used for low concentration gas catalytic combustion reaction（methane volume fraction is 1.69%）.The effects of the preparation method,calcination temperature and n（Co）:n（Cu） on the catalyst performance were investigated.The catalyst was characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,hydrogen programmed temperature reduction（H2-TPR） and X-ray photoelectron spectroscopy（XPS）.The optimum calcination temperature and n（Co）:n（Cu） are 400℃ and 1:1,respectively.The catalyst prepared under these conditions has the highest catalytic activity.The results show that the catalysts prepared by coprecipitation method have higher catalytic activity than that prepared by sol-gel method（n（citric acid）:n（metal ion） is 3:2）.The characteristic methane conversion temperatures of t10,t50 and t90（at which methane conversion rate is 10%,50%,and 90%respectively） are lower by 6℃,70℃ and 1℃,respectively.关键词：low concentration gas;catalytic combustion;Co-Cu composite oxide;catalyst
- 7
- |
- 37
- |
- 0
发布时间：2023-08-31 - 摘要：Volatile organic compounds（VOCs） are important ingredients of air pollutants, which can cause serious harm to ecological environment and human health, so it is particularly important to design and prepare efficient catalysts to degrade VOCs. As catalysts for commercial application, molecular sieve exhibits the advantages of excellent stability and high resistance to toxicity. However,due to the poor catalytic activity of single molecular sieve, loading active components is needed to further improve the catalytic performance. Cu-Fe/ZSM-5, Cu-Fe/Beta and Cu-Fe/SAPO-34 catalysts were prepared by ultrasonic method using different molecular sieves（ZSM-5, Beta and SAPO-34） as carriers simultaneously loaded with Cu and Fe transition metal oxides and used for the catalytic oxidation of toluene. The results of catalytic activity test show that Cu-Fe/ZSM-5 catalyst possesses excellent catalytic activity, with the conversion rate of toluene up to 90% at 300 ℃. The X-ray diffraction（XRD） analysis results show that the molecular sieves simultaneously loaded with Cu and Fe metal oxides do not cause obvious damage to the molecular sieve structure, and the metal oxides have good dispersion. The results of NH3 temperature programming（NH3-TPD） analysis show that acidity is not the only factor affecting catalytic activity. The results of in situ diffuse reflection infrared（in situ DRIFT） and chromatography-mass spectrometry（GC-MS） analysis show that the less intermediates are generated on the catalyst with better catalytic activity, while more intermediates are generated on the catalyst with poor catalytic activity.关键词：Cu-Fe loaded;molecular sieve;ultrasonication;toluene;catalytical oxidation
- 4
- |
- 33
- |
- 0
发布时间：2023-08-31 - 摘要：The mixture of isopropanol-water was separated with ethylene glycol as the extractant.With the goal of energy reduction,cost saving and CO2 emissions reduction,heat pump and heat integration technology were used to strengthen the extractive distillation process.Using Aspen Plus software,the conventional extractive distillation,the heat pump extractive distillation and the heat integrated-heat pump extractive distillation were simulated.The above processes were evaluated and compared from the energy consumption,total annual cost（TAC） and CO2 emissions.Under the same design basis and requirements,the results show that heat pump technology with compressor performance coefficient of 10.19 can significantly reduce energy consumption.Compared with the conventional extractive distillation,the heat pump extractive distillation scheme 2 can save energy by 28%,reduce CO2 emissions by 3.746×10~6 kg/a and reduce TAC by 0.72×10~5 USD when the payback period is 3 a.The heat integrated-heat pump extractive distillation which make full use of the sensible heat of circulating extractant has more advantages.It can save energy by 35%,reduce CO2 emissions by 8.457×10~6 kg/a and reduce TAC by 1.70×10~5 USD,has better environmental and economic benefits.关键词：isopropanol-water;extractive distillation;heat pump;heat integration;total annual cost;CO2 emissions
- 7
- |
- 221
- |
- 0
发布时间：2023-08-31 - 摘要：Coal-to-methanol is one of the key industries of cleaner production audit. Using SimaPro software, the life cycle assessment of main units such as gasification, methanol, boiler and air separation in the coal-to-methanol project（coal-water slurry process） of an enterprise in Shaanxi was carried out. Eleven indicators were selected for environmental impact assessment, and the calculation of characterization, damage assessment, standardization, weighting and process contribution was carried out. The correlation between environmental impact and unit process was analyzed from the characteristics of resource and energy use and pollutant emission.The results show that in the whole life cycle of coal-to-methanol, the comprehensive impact of gasification unit on the environment accounts for 74.7%, methanol unit accounts for 24.7%, followed by air separation unit and boiler unit. For a single indicator, the gasification unit has the largest impact on carcinogens, respiratory organic matter, respiratory inorganic matter, radiation, ozone layer,ecotoxicity, acidification/eutrophication, land use, minerals and fossil fuels, and the methanol unit has the largest impact on climate change.关键词：coal-to-methanol;environmental impact;life cycle assessment;SimaPro software;cleaner production
- 4
- |
- 213
- |
- 0
发布时间：2023-08-31 -
Sintered flue gas SCR denitrification system flow field simulation and inflow structure optimization
摘要：Selective catalytic reduction（SCR） technology can effectively effectively solve the problem of NOx non-compliance in iron ore sinter flue gas emissions and achieve ultra-low emissions of waste gases. The uniformity of the physical field distribution such as flow field, temperature, pressure and concentration ratio of ammonia-nitrogen in the SCR reactor are important factors in determining the denitrification efficiency. Based on the low denitrification efficiency and ammonia escape problem in a steel plant, the flow field was numerically simulated using FLUENT software to compare and analyze the values and uniformity of the distribution of each physical field such as flow field, temperature, pressure and concentration ratio of ammonia-nitrogen in the SCR reactor, considering the chemical reactions in the reactor during denitrification. The uniformity of the physical fields is greatly improved by adding a rectifier grille and optimizing the structure of the deflectors, and the denitrification efficiency is improved. After structure optimization, the deviation of flue gas flow rate inhomogeneity upstream of the first layer of catalyst is reduced to 8.48%, the deviation of temperature inhomogeneity is reduced to 4 K,and the deviation of concentration ratio of ammonia-nitrogen inhomogeneity is reduced to 4.71%, which satisfied the design requirements.In addition, the optimization of the deflectors structure should take into account the number, thickness, shape and spacing of the baffles, etc.With the increase of the number of deflectors at the elbow on the flue, the deviation of the flue gas velocity inhomogeneity upstream of the first layer of catalyst is gradually reduced, which effectively improves the uniformity of the airflow distribution in the reactor.关键词：SCR;sintering flue gas;denitrification;numerical simulation;deflectors- 4
- |
- 93
- |
- 0
发布时间：2023-08-31 - 摘要：Chemical absorption method is the most potential and most widely used carbon dioxide capture technology. However, high renewable energy consumption is also a common problem, which increases the cost of carbon capture and restricts the promotion of chemical absorption carbon capture technology. The chemical absorbents（amine absorbent, two-phase absorbent, homogeneous aqueous absorbent, ionic liquids and deep eutectic solvent） and carbon capture technological process（absorption process optimization,desorption process optimization and composite process optimization） were summarized. The future development of chemical absorption method was prospected. The analysis shows that the key research direction in future will be developing novel mixed amine systems, designing deep eutectic solvent, declining the viscosity and cost of two-phase absorbent, homogeneous aqueous absorbent and ionic liquids, and achieving the low-energy regeneration. When improving the absorption process and desorption process, it is necessary to make full use of the waste heat in systems. In order to reduce the energy consumption of the system to get the greatest extent, several optimization methods of single process should be reasonably combined to improve the composite process.关键词：carbon capture;chemical absorption method;new absorbent;optimization of trapping process
- 6
- |
- 313
- |
- 0
发布时间：2023-08-31 - 摘要：Carbon dioxide（CO2） chemical absorption method has matured and is an effective industrial carbon capture technology.Anhydrous phase change absorbents exhibit high absorption rates and low desorption energy consumption.However,in the industrial CO2 absorption process,the water in the gas source is absorbed by the anhydrous phase change absorbent,affecting the subsequent absorption effect.The performance changes of the typical anhydrous mixed amine phase change absorbent（diethanolamine-pentamethyldiethylenetriamine-ethylene glycol,P-T-EG） in capturing CO2 from simulated flue gas containing water were investigated.The effects of water accumulation on the rich phase ratio（volume ratio）,CO2 loading,and the moisture content（mass fraction,the same as below） of lean and rich phases after phase separation were explored.The results show that the accumulation of water is beneficial to reducing the viscosity of the rich phase and increasing the rich phase ratio.As the number of cycles increases,the rich phase ratio increases,and the moisture content of the lean phase is lower than that of the rich phase.The impact of water accumulation on desorption equilibrium is weak.Using Aspen Plus,the desorption process of P-T-EG rich phase with different moisture contents was calculated.It is found that at a reboiler temperature of 100℃ and a condensation temperature of 35℃,P-T-EG+10%H2O（10%is the moisture content） can achieve a balance between absorption and desorption water.At this time,the mass loss of amine in the desorption column is 1.05×10-10（mass ratio）.关键词：anhydrous absorbent;phase change;CO2;moisture content;tertiary amine;phase splitting behavior
- 4
- |
- 55
- |
- 0
发布时间：2023-08-31 - 摘要：The chemical absorption method with N-methyldiethanolamine（MDEA） + piperazine（PZ） aqueous solution as the composite absorbent is one of the important means for CO2 capture. However, the high regeneration energy consumption of this composite absorbent limits its application in the field of carbon capture. In order to overcome this shortcoming, some certain additive is added to form phase change absorbent to reduce the total amount of absorbent into the desorption unit, so as to reduce the energy consumption for regeneration. A liquid-solid phase change absorbent with the composition of MDEA + PZ + N-methylpyrrolidone（NMP） + water（H2O） was designed. The CO2 absorption performance of the liquid-solid phase change absorbent was investigated, the effects of mass fraction of NMP and PZ on the CO2 solubility were determined, and the mechanism of liquid-solid phase separation behavior mechanism was also analyzed. The results show that, the CO2 solubility of the liquid-solid phase change absorbent decreases with the increase of the mass fraction of NMP and increases with the increase of the mass fraction of PZ. When the mass fraction of NMP and PZ in the absorbent reaches 50% and 3% and above, respectively, the PZ-carbamate formed by absorbing CO2 can reach saturation and precipitate to form a solid phase. The solid phase first increases with the increase of CO2 solubility, and then PZdicarbamate which is more soluble in water is formed with the increase of CO2 solubility, resulting in the decrease of solid phase.关键词：CO2 capture;phase change absorbent;phase separation behavior;MDEA;NMP
- 4
- |
- 62
- |
- 0
发布时间：2023-08-31 - 摘要：A high concentration CO2（50%, volume fraction） tail gas treatment scenario in a petrochemical emission process was simulated. The primary and tertiary amine solutions were compounded to establish blended amine titanium-based nanofluid with both fast reaction performance and high absorption capacity. By self-designed and built 10 t/a scale packed tower CO2 absorption-desorption cycle experimental system, the comprehensive enhanced mechanism of CO2 absorption-desorption by nanofluid absorbent in packed tower was investigated. It is found that the nanofluid absorbent could increase the capacity of the absorption-desorption cycle by up to 40% compared to blended amines. Increasing the CO2 loading in the lean liquid will weaken the contribution of nanoparticles to the CO2 capture performance of the absorbent. When the CO2 loading reached 0.4 mol/mol（1 mol amine loaded with 0.4 mol CO2）, the volumetric overall mass transfer coefficient of the nanofluid absorbent is essentially the same as that of the blended amine absorbent.The enhanced interaction between nanoparticles in the system leads to the formation of micro-convection within the liquid phase, which can enhance the CO2 absorption performance of the capture system. However, when the nanoparticle mass concentration exceeds 0.12%,the micro convection and solid shuttle effects in the liquid phase are weakened by particle agglomeration. Therefore, effective measures are needed to disperse the agglomerated nanoparticles during the circulation process. How to enhance the stability of nanoparticle dispersion by coupling external perturbation and internal chemical dispersion will be one of the key directions for subsequent research.关键词：nanofluid;blended amine;high concentration CO2;packed tower
- 6
- |
- 21
- |
- 0
发布时间：2023-08-31 - 摘要：Ammonia borane（AB） is a liquid-phase hydrogen storage material that has gained significant attention due to its high hydrogen content. However, the slow rate and the uncertain catalytic mechanism of AB hydrolysis have hindered its large-scale application. Therefore, the development of efficient supported catalysts for AB hydrolysis to generate hydrogen is of great importance.The research progress on catalysts for hydrolysis of AB was reviewed, focusing on active center materials and carrier materials such as carbon materials, metal oxides, metal hydroxides, transition metal carbides, two-dimensional transition metal carbonide/nitrides,metal-organic frameworks, metal nitrides, and covalent organic frameworks. The reaction mechanism of AB hydrolysis was discussed,and the future development of AB hydrolysis for hydrogen production was also prospected.关键词：ammonia borane;supported catalyst;carrier materials;catalytic mechanism
- 4
- |
- 0
- |
- 0
发布时间：2023-08-31 - 摘要：Efficient recovery of low carbon light hydrocarbons from natural gas has important economic value. To accurately determine the ability of natural gas produced in different blocks of the Tarim oilfield to produce liquid hydrocarbons at low temperature（243.15 K）, natural gas samples were obtained from the on-site treatment station by using the pressure preserving sampling method, and then the high-pressure and low-temperature phase equilibrium experiment was carried out. Based on the results of the phase state experiment, the thermodynamic prediction model of natural gas flash was established. Finally, combined with material balance, the liquid hydrocarbon capacity of natural gas at low temperature was determined. The potential liquid hydrocarbon production of seven natural gas samples, TZ（processing station code, the same as below） is 596.42 g/m~3, YH is 177.10g/m~3, DN is 145.52 g/m~3, LN is 39.23 g/m~3, DB is 27.28 g/m~3, KL is 4.59 g/m~3, and YM is 60.23 g/m~3. The results of the study match well with the actual field data, and have a guiding role in setting the operating conditions of on-site natural gas treatment stations and constructing low-temperature dehydrocarbon devices.关键词：natural gas;liquid hydrocarbon;phase equilibrium;flashing model;pressure maintaining sampling
- 4
- |
- 23
- |
- 0
发布时间：2023-08-31 - 摘要：The models used to predict the solubility of elemental sulfur in acid gas are mostly based on semi empirical formulas established by experiments, which are not applicable to a wide range of temperature and pressure, and few factors are considered.Based on the traditional equation of state, the PR equation was used as a prototype, and the repulsion term of the equation was modified. The thermodynamic parameters of the equation of state were obtained by fitting the experimental results of elemental sulfur solubility. Comparing the prediction results of the modified model with 32 experimental values, the average relative error is 4.01%.The results show that the model can be used to predict the solubility of elemental sulfur in acid gas without relevant experimental data.关键词：elemental sulfur;solubility;gas-liquid-solid;prediction model
- 4
- |
- 67
- |
- 0
发布时间：2023-08-31 - 摘要：In the process of unconventional natural gas and carbon dioxide（CO2） replacement extraction of natural gas hydrate,it is important to clarify the synthesis and decomposition mechanism of CO2/CH4 mixed gas hydrate（hereinafter referred to as “CO2/CH4 hydrate”） for the separation of mixed gas,CO2 sequestration and efficient CH4 extraction by hydrate method.The secondary synthesis and decomposition experiments of CO2/CH4 hydrate in porous media+deionized water system were carried out to study the effect of memory effect on the synthesis of CO2/CH4 hydrate under the decomposition time of 0.5 h and the decomposition temperature of 5℃ to 25℃.The secondary synthesis induction period,gas consumption and consumption rate,and gas consumption of each component were mainly analyzed.The results show that the induction period of secondary synthesis become shorter when the decomposition temperature is lower.The memory effect reduces the rate of secondary synthesis.The fastest rate of secondary synthesis is achieved when the decomposition temperature is 10℃,and the peak gas consumption rate is 8.10 mmol/min.Under the same synthesis temperature and pressure,the memory effect after heating decomposition increases the synthesis amount of CO2 hydrate to 1.3 times that of the primary synthesis amount during the secondary synthesis,but has no effect on the synthesis amount of CH4 hydrate,that is,the effect of memory effect on different guest molecules is different.This study provides a reference for the application of memory effect in hydrate technology.关键词：CO2;CH4;mixed gas hydrate;memory effect;hydrate synthesis;hydrate decomposition
- 4
- |
- 48
- |
- 0
发布时间：2023-08-31 - 摘要：Aiming at the problem of equipment parameter fluctuations in liquefied natural gas（LNG） terminal when operating conditions change, the dynamic model of LNG terminal process flow was established by using HYSYS software. The empirical trialand-error method was used to analyze the influence law of proportional, integral and differential coefficients of PID controller on tank pressure, re-condenser level and low-pressure pump flow to reduce the fluctuation and un-stability in the operation of LNG terminal.The results show that in the tank pressure control system with proportional and integral control, when the proportional coefficient is changed from 1 to 4, the recovery time to the set value can be saved by 55.6% and the recovery time can be significantly shortened by adding integral control. In the re-condenser level control system, single proportional control can be used under the condition that static difference is allowed when the proportional coefficient is changed from 0.5 to 5.0, the recovery time to the set value can be saved by 62.9%, and the integral coefficient has no obvious effect on the level control. In the low pressure pump flow control system with proportional and integral control, the change of the integral coefficient has a more obvious effect on the flow control system when the integral coefficient is reduced from 3.0 to 0.5, the recovery time to the set value can be saved by 72.9%. Finally, the recommended parameters of the three control systems were given, which can provide reference for the selection of PID controller parameters in LNG terminal.关键词：LNG terminal;dynamic simulation;PID control;parameter tuning
- 4
- |
- 180
- |
- 0
发布时间：2023-08-31 - 摘要：Natural gas separation is the main way for industrial production of helium,but the low helium content（mole fraction,the same as below） of natural gas in most gas fields in China causes that more than 95%of helium in China depends on imports.Aiming at the natural gas with low helium content（less than 0.5%）,a process scheme of extracting helium by combining low temperature and high pressure concentration,natural gas liquefaction and low temperature rectification was put forward.Take an ethane recovery plant（feed gas temperature is 50℃,feed pressure is 5.8 MPa,treatment capacity is 1000×10~4 m~3/d） as an example,the process scheme of extracting helium from low helium natural gas and co-producing liquified natural gas（LNG） was simulated by Aspen HYSYS software.On the premise of controlling the helium concentration multiple to 19.15,the key parameters of the low-temperature and high-pressure concentration device were analyzed,and the adaptability of the process flow to the content of CO2 and nitrogen in the feed gas was studied.It is found that too high pressure in the concentration tower will lead to an increase in helium loss at the bottom of the tower,and too low pressure will lead to an increase in the power of the export gas compressor,so a reasonable tower pressure of3.8 MPa is set for this feed gas.The increase of the tray number in the concentration tower will increase the helium recovery rate,but the increase of helium recovery rate is not obvious when the tray number is greater than 16.When the CO2 content of the feed gas is lower than 2%,the concentration tower will not form CO2 frozen blockage.When the nitrogen content of feed gas is higher than 0.5%,it is necessary to denitrify the overhead gas to meet the quality standard of LNG production.关键词：low helium natural gas;low temperature and high pressure concentration;natural gas liquefaction;HYSYS software
- 5
- |
- 231
- |
- 0
发布时间：2023-08-31 - 摘要：Combined with three LNG light hydrocarbon recovery processes reported in the literature, a new process using the cold energy released during the vaporization of liquefied natural gas（LNG） was proposed. Using HYSYS simulation software and P-R state equation for thermodynamic method, sensitivity analysis of the new process was carried out. The optimal inlet temperature of flash column, the top pressure of demethanizer and the top pressure of deethanizer are determined to be -105 ℃, 2800 kPa and 2000 kPa, respectively. Through comparison, it is found that the new process has certain advantages in methane production, ethane recovery and equipment exergy analysis.关键词：LNG;light hydrocarbon recovery;methane production;ethane recovery;exergy analysis;HYSYS
- 5
- |
- 251
- |
- 0
发布时间：2023-08-31 - 摘要：Before natural gas liquefaction,the raw natural gas needs to be purified to remove CO2,H2O,H2S and heavy hydrocarbon(C5 and above hydrocarbons,abbreviated as“C5+”) components in it,so as to prevent the above components from freezing and forming solid in the liquefaction section and blocking the pipeline and equipment.Taking a western liquefied natural gas（LNG） plant as an example,in view of the large variation and high content（mole fraction,the same as below） of C5+components of raw natural gas in the pipeline of the plant,the original C5+component removal process was reconstructed and designed based on the analysis and detection of raw natural gas components,and the designed C5+ component removal process was simulated and calculated with Aspen Hysys software and applied to production.Finally,the components of purified natural gas in production were detected and analyzed.The research shows that the C5+ component removal process combined with low temperature condensation pre-separation and high performance activated carbon adsorption is theoretically feasible.Under the condition that the C5+ components of natural gas meet the requirements of liquefaction process,the C2～C4 components are retained to the maximum extent,and the heating value of LNG is improved.In the simulation results,the C5+ component content in the natural gas after C5+ component removal is 0.007265%,which is similar to 0.0076%of C5+ component content in the natural gas after purification in the actual production.关键词：natural gas;heavy hydrocarbons removal;liquefaction;process reconstruct;simulation and calculation
- 6
- |
- 137
- |
- 0
发布时间：2023-08-31
- Postal code：610225
- Tel：028-85964717 Email：dthxyhg@swchem.com
- Technical support is provided by Beijing Founder electronics co., LTD 蜀ICP备12008600号-10
蜀公网安备51012202001533 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
- Total Visits：6276
0