共查询到20条相似文献,搜索用时 15 毫秒
1.
首先采用实验室自制椰壳活性炭为吸附剂,进行了氮气/甲烷(65%/35%)原料气的真空变压吸附工艺(VPSA)分离实验。通过对比实验和gPROMS 动态模拟软件的分离效果,对变压吸附数学模型进行了验证,证明了所采用数学模型的准确性。在此基础上,对影响产品气甲烷纯度、回收率的关键决策变量进行了灵敏度分析。分析结果表明:产品气纯度主要由原料气流量和置换气流量来进行调控,产品气回收率则需要关键变量共同的作用才能实现最大化。依据灵敏度分析结果,对两塔分离氮气甲烷混合气的变压吸附工艺进行了动态优化。在最优的工况下,可以将进料组成为35%的甲烷富集到75%,回收率达到97.08%;从而达到对于废混合气的高效回收利用。 相似文献
2.
为了有效地捕集焦炉气及煤层气中的甲烷,提出了一种新型捕集技术:吸收-吸附组合方法,该方法通过把ZIF-8分散到乙二醇水溶液中形成悬浮浆液,实现对甲烷组分的捕集。首先测定了甲烷、氮气和氢气在浆液中的吸收-吸附容量,得出吸着量大小的顺序为CH4> N2> H2,然后对CH4/H2和CH4/N2的混合气进行吸着平衡研究,发现浆液均能有选择性地吸着甲烷。对浆液中回收的ZIF-8材料进行XRD表征,分析证明在整个吸着过程中ZIF-8结构没有发生变化并且ZIF-8/乙二醇-水浆液能重复利用。 相似文献
3.
非常规天然气未来可以作为常规天然气的有效补充,其中低浓度煤层气和生物质燃气分别需要脱除大量的N2 和CO2以达到富集和纯化CH4的目的。本研究针对CH4/N2这一对较难分离的气体组合,选取了具有一维菱形孔道的MOFs材料Cu(INA)2作为吸附剂,将合成的样品做了XRD和TG表征,测试了纯气体CO2、CH4和N2的吸附曲线,利用巨正则系综蒙特卡罗(GCMC)分子模拟和理想吸附溶液理论(IAST)计算了气体的吸附热和该材料对于CH4/N2和CO2/CH4的吸附选择性系数;3 MPa压力下制备的颗粒样品填装吸附分离装置,进行了混合气体CH4/N2 (50%/50%)和CO2/CH4 (50%/50%)的穿透试验,分离的结果显示,Cu(INA)2不仅高选择性地吸附CH4/N2混合物中的CH4(SCH4/N2=10),而且对CH4/N2的分离效果优于CO2/CH4。 相似文献
4.
《分离科学与技术》2012,47(6):874-885
Adsorption equilibrium, thermodynamics, and kinetics of CH4, N2, and CO2 were investigated by volumetric-chromatographic and inverse gas chromatographic (IGC) methods on the Al-BDC MOF. The binary adsorption data from the volumetric-chromatographic experiments represents that the Al-BDC MOF has a high CO2/CH4 selectivity ca. 11 and a CH4/N2 selectivity ca. 4.3 at 303 K, and appears to be a good candidate for the CH4 separation. The initial adsorption heats of CH4, N2, and CO2 on the Al-BDC MOF were determined to be 15.3, 11.5, and 32.2 kJmol?1 by IGC method, respectively. Moreover, the micropore diffusivities of N2, CH4 and CO2 in the Al-BDC MOF at 303 K were also estimated to be 1.58 × 10?7 cm2/s, 7.04 × 10?8 cm2/s, and 3.95 × 10?9 cm2/s, respectively. The results indicate that micropores play a crucial role in the adsorptive separation of the CH4/N2 and CH4/CO2 mixtures, and the IGC method is a validity manner to estimate the thermodynamic and kinetic parameters of MOF adsorbents. 相似文献
5.
Xiaohong Shao Zhenhe Feng Ruisheng Xue Congcong Ma Wenchuan Wang Xuan Peng Dapeng Cao 《American Institute of Chemical Engineers》2011,57(11):3042-3051
A series of high performance carbonaceous mesoporous materials: activated carbon beads (ACBs), have been prepared in this work. Among the samples, ACB‐5 possesses the BET specific surface area of 3537 m2 g?1 and ACB‐2 has the pore volume of 3.18 cm3 g?1. Experimental measurements were carried out on the intelligent gravimetric analyzer (IGA‐003, Hiden). Carbon dioxide adsorption capacity of 909 mg g?1 has been achieved in ACB‐5 at 298 K and 18 bar, which is superior to the existing carbonaceous porous materials and comparable to metal‐organic framework (MOF)‐177 (1232 mg g?1, at 298 K and 20 bar) and covalent‐organic framework (COF)‐102 (1050 mg g?1 at 298 K and 20 bar) reported in the literature. Moreover, methane uptake reaches 15.23 wt % in ACB‐5 at 298 K and 18 bar, which is better than MOF‐5. To predict the performances of the samples ACB‐2 and ACB‐5 at high pressures, modeling of the samples and grand canonical Monte Carlo simulation have been conducted, as is presented in our previous work. The adsorption isotherms of CO2/N2 and CO2/CH4 in our samples ACB‐2 and 5 have been measured at 298 and 348 K and different compositions, corresponding to the pre‐ and postcombustion conditions for CO2 capture. The Dual‐Site Langmuir‐Freundlich (DSLF) model‐based ideal‐adsorbed solution theory (IAST) was also used to solve the selectivity of CO2 over N2 and CH4. The selectivities of ACBs for CO2/CH4 are in the range of 2–2.5, while they remain in the range of 6.0–8.0 for CO2/N2 at T = 298 K. In summary, this work presents a new type of adsorbent‐ACBs, which are not only good candidates for CO2 and CH4 storage but also for the capture of carbon dioxide in pre‐ and postcombustion processes. © 2011 American Institute of Chemical Engineers AIChE J, 2011 相似文献
6.
Angel de J. Montes Luna Nidia C. Fuentes López Griselda Castruita de León Odilia Pérez Camacho Claudia Y. Yeverino Miranda Yibran A. Perera Mercado 《应用聚合物科学杂志》2021,138(14):50155
In this work, polybenzimidazole (PBI)-based mixed matrix membranes (MMMs) with natural zeolite were prepared and their transport properties for binary (N2/CH4) and ternary (CO2/N2/CH4) mixed-gas separation were studied. The MMMs, were prepared with PBI as polymeric matrix and Mexican natural zeolite clinoptilolite enriched with cations of Ca2+ as filler. The thermal properties analysis of the PBI and MMMs studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicates that the MMMs membranes have Tg higher than 350°C and decomposition temperatures above 600°C compared with the pristine membranes. PBI membrane and MMMs were analyzed by X-Ray Diffraction (XRD) and the diffraction patterns showed the zeolite signals combine with the amorphous dome from the polymeric matrix. In addition, the perm-selectivity properties of the polymeric membranes and MMMs were tested with binary (N2/CH4; 10/90 mol%) and ternary (CO2/N2/CH4; 5/10/85 mol%) gas mixtures at different pressure rates (50, 150 and 300 psi). The perm-selectivity properties of the MMMs membranes show an improvement in their values about 30% higher compared to the PBI polymeric membranes, favoring the permeation of CO2 and N2. 相似文献
7.
Yalou Guo Vincent Jusko Gongkui Xiao Jurgen Hanekom Guoping Hu Paul A. Webley Eric F. May Gang Kevin Li 《American Institute of Chemical Engineers》2022,68(5):e17569
Conventional pressure swing adsorption (PSA) processes can only produce one high purity product in a single stage, whereas the state-of-art dual-reflux PSA (DR-PSA) can produce two high purity products simultaneously. However, multicomponent gas separation is often required in the industry, targeting at recovering several valued products at the same time. In this study, we propose a novel adsorption process, namely triple-reflux PSA (TR-PSA), to separate three components simultaneously. A middle product outlet and a middle reflux stream were introduced to the adsorption columns of a conventional DR-PSA process to separate ternary mixtures of nitrogen, methane, and helium. Nonisothermal dynamic models were built to investigate the impacts of operating parameters particularly the location of the middle reflux/product stream and the middle reflux flow rates. Results showed that the TR-PSA process successfully separated ternary mixtures obtaining three enriched products simultaneously in a single stage, yielding a separation performance comparable to that of the double-stage DR-PSA with significantly lower capital and energy cost. 相似文献
8.
Muhammad Chawla Hammad Saulat Muhammad Masood Khan Muhammad Mahmood Khan Sikander Rafiq Linjuan Cheng Tanveer Iqbal M. Imran Rasheed Muhammad Zohaib Farooq Muhammad Saeed Nasir M. Ahmad Muhammad Bilal Khan Niazi Sidra Saqib Farrukh Jamil Ahmad Mukhtar Nawshad Muhammad 《化学工程与技术》2020,43(2):184-199
Membrane technology has emerged as a leading tool worldwide for effective CO2 separation because of its well-known advantages, including high surface area, compact design, ease of maintenance, environmentally friendly nature, and cost-effectiveness. Polymeric and inorganic membranes are generally utilized for the separation of gas mixtures. The mixed-matrix membrane (MMM) utilizes the advantages of both polymeric and inorganic membranes to surpass the trade-off limits. The high permeability and selectivity of MMMs by incorporating different types of fillers exhibit the best performance for CO2 separation from natural gas and other flue gases. The recent progress made in the field of MMMs having different types of fillers is emphasized. Specifically, CO2/CH4 and CO2/N2 separation from various types of MMMs are comprehensively reviewed that are closely relevant to natural gas purification and compositional flue gas treatment 相似文献
9.
10.
Prachya Watasit Suparat Rukchonlatee Artit Ausavasukhi Chonlada Ritvirulh Tawan Sooknoi 《应用聚合物科学杂志》2021,138(42):51229
The CO2 and CH4 permeabilities of poly(ethylene-co-vinyl acetate) (EVA)/SiO2 composite membrane were investigated at atmospheric pressure. The membranes were fabricated by compression molding and characterized by Fourier transformed infrared spectroscopy, differential scanning calorimetry, a universal testing machine, and a contact angle analyzer. The effect of vinyl acetate content (18–33 wt%) was evaluated for both single-gas and mixed-gas permeation systems. A non-pressurized homemade-permeation cell was used for the single-gas permeation of CO2 and CH4, while a tubular membrane was utilized for a continuous separation of CO2/CH4 mixture. CO2 flux was readily increased (from 0.7 to 2.0 ml/m2.s) with vinyl acetate content (18–33 wt%). The enhanced CO2 permeability is attributed to the increase in polarity and also the decrease in crystallinity of the membrane. A satisfied gas separation selectivity (CO2/CH4) of 4.31 could be obtained from tubular membrane with 28 wt% VA content. The incorporation of SiO2 as a filler (0.5–2.0 wt%) especially increased the membrane polarity and hence the CO2 flux up to 6.0 ml/m2.s. However, the CH4 flux was not affected by VA and SiO2 contents. 相似文献
11.
《应用化工》2022,(3):842-848
SnO_2/Sn甲烷还原及水分解的太阳能燃料转换方法,有还原温度低、燃料选择性高、操作范围广的特点。运用HSC化学热力学软件对SnO_2/Sn甲烷太阳能燃料化的循环进行了计算与分析,研究了还原温度、反应物配比、还原反应器中气体压力对生成物质组分、燃料能量升级因子和能量转换效率的影响。结果表明,CH_4的引入可降低SnO_2的还原温度,还原温度高有利于反应进行;高压力(p)使SnO_2还原温度提高并降低能量升级因子及太阳能燃料转换效率;温度低有利于水氧化反应的进行,过大的X(H_2O/Sn摩尔比)会降低太阳能燃料转化效率。在p=0.1 MPa,R=2,X=2,T_(red)=1 260℃,T_(oxi)=25℃时可获得最大的太阳能燃料转化效率0.50。 相似文献
12.
《Gas Separation & Purification》1991,5(2):67-75
An isosteric sorption apparatus has been used to obtain data for the sorption of N2, CH4 and CO2 in Silicalite-1 over the temperature range 0–70°C. Isotherms have also been determined in a high pressure sorption balance at equilibrium pressures up to 20 atm. Isosteric heats of sorption have been calculated from these sorption data. Separation factors calculated from Henry's Law constants determined from the initial slopes of the single-component isotherms have been found to be in good agreement with experimental separation factors. The single-component sorption data have been fitted to various isotherm models and the Ideal Adsorbed Solution theory has been used to predict a binary sorption isotherm from the respective single-component data. The predicted isotherm is in good agreement with the corresponding experimental isotherm. 相似文献
13.
A comprehensive experimental and numerical study has been conducted to understand the influence of CH3Cl addition on CH4/O2/N2 premixed flames under oxygen enrichment. The laminar flame speeds of CH4/CH3Cl/O2/N2 premixed flames at room temperature and atmospheric pressure are experimentally measured using the Bunsen nozzle flame technique
with a variation in the amount of CH3Cl in the fuel, equivalence ratio of the unburned mixture, and level of oxygen enrichment. The concentrations of major species
and NO in the final combustion products are also measured. In order to analyze the flame structure, a detailed chemical kinetic
mechanism is employed, the adopted scheme involving 89 gas-phase species and 1017 elementary forward reaction steps. The flame
speeds predicted by this mechanism are found to be in good agreement with those deduced from experiments. Chlorine atoms available
from methyl chloride inhibit the oxygen-enhanced flames, resulting in lower flame speeds. This effect is more pronounced in
rich flames than in lean flames. Although the molar amount of CH3Cl in the methane flame is increased, the temperature at the post flame is not significantly affected, based on the numerical
analysis. However, the measured concentration of NO is reduced by about 35% for the flame burning the same amount of methyl
chloride and methane at the oxygen enrichment of 0.3. This effect is due to the reduction of the concentration of free radicals
related to NO production within the flame. In the numerical simulation, as CH3Cl addition is increased, the heat flux is largely decreased for the oxygen-enhanced flame. It appears that the rate of the
OH + H2 → H + H2O reaction is reduced because of the reduction of OH concentration. However, the function of CH3Cl as an inhibitor on hydrocarbon flames is weakened as the level of oxygen enrichment is increased from 0.21 to 0.5.
__________
Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 6, pp. 103–111, November–December, 2006. 相似文献
14.
沼气吸收法脱硫过程中,带有流量循环式双容器串联性质的脱硫塔和富液槽的液位可以采用间接控制方法。通过采用富液和贫液的流量比值控制,并研究富液槽液位波动合理的范围,找到其液位波动动态平衡点,实现对脱硫塔、富液槽液位均匀控制的目标。消除富液槽满罐或排尽的现象。针对当前的工艺设备参数进行研究计算得出结论:流量比值系数理论上为1;富液槽液位的合理波动范围在0.264m。 相似文献
15.
由于ZIF-8浆液独特的可流动性,可以借鉴传统的吸收-解吸工艺,实现煤层气中甲烷的多级连续高效富集。在单吸收-吸附塔工艺的基础上,为了进一步降低能耗,提出了高低压双吸收-吸附塔新型分离工艺,并对该工艺进行了全流程建模及模拟。采用平衡级法,建立了工艺流程中各单元传质设备的数学模型,包括吸收-吸附塔、闪蒸罐、解吸塔。此外,还进行了灵敏度分析,探究了平衡级数、进料位置、气液比、解吸压力等因素对产品气中甲烷浓度以及回收率等工艺性能的影响。模拟结果表明,当产品气中甲烷浓度达到90.13%(mol)时,回收率为90.25%。并且单位原料气能耗为0.445 kW·h∙m-3(原料气),低于单塔能耗(0.510 kW·h∙m-3)。由此,改进的双塔工艺在满足甲烷纯度和回收率的同时,相较于单塔工艺进一步降低了能耗。 相似文献
16.
The separation between methane and nitrogen is an inevitable and important task in the C1 chemical technology and the utilization of methane from coalbed, yet it is considered to be one of the tough tasks in the field of separation. Pressure swing adsorption is a preferable technology if an adsorbent that allowing a large coefficient of separation for the CH4/N2 system is available. The separation coefficients between CH4 and N2 were obtained on analyzing the breakthrough curves measured experimentally with nine adsorbents. A technique of measuring the temperature-pulse was incorporated in the experiments, and the reliability of the result was improved. Superactivated carbon with large surface area and plenty of micropores was shown to have the largest separation coefficient and to be promising for the commercial utilization. 相似文献
17.
18.
19.
煤层气(CBM)是一种非常规天然气。在中国,煤层气在抽采出来时常混有空气。考虑到安全因素,氧气首先应该被去除。之后,煤层气利用的最重要步骤则是甲烷-氮气混合气体的甲烷高效提浓。本文搭建了双床变压吸附(PSA)装置,选择特定的炭分子筛(CMS)进行CH4/N2混合物分离实验研究。由于CMS的动力学吸附特性,氮被吸附在CMS上,带有一定压力的甲烷则连续输出。研究了吸附压力、进气速度和循环周期等因素对吸附过程整体性能的影响。从50% CH4/50% N2的原料气可以获得95.45%纯度的甲烷产品,而从30% CH4/70% N2的原料气可以获得94.89%纯度的甲烷产品。研究表明,以上3个参数都对分离性能有影响,其中后两者的影响更大。在较低吸附压力和较低进气速度时更容易获得纯度90%以上的甲烷产品。另外,循环周期越短,获得的甲烷纯度越高。 相似文献
20.
Ultraviolet‐ray treatment of polysulfone membranes on the O2/N2 and CO2/CH4 separation performance 下载免费PDF全文
Sutthisa Konruang Suksawat Sirijarukul Pikul Wanichapichart Liangdeng Yu Thawat Chittrakarn 《应用聚合物科学杂志》2015,132(25)
UV irradiation on polysulfone (PSF) membranes was studied to improve their gas‐separation properties. Membranes with 19–25% PSF contents were prepared by the phase‐inversion method, and the membrane surface was modified with UV rays with a wavelength of 312 nm and a power of 360 µw/cm2. Measurements of gas permeation were conducted with pure carbon dioxide (CO2), methane (CH4), oxygen (O2), and nitrogen (N2) gases under 3–8 bar pressure at 25°C. Fourier transform infrared spectrometry revealed that the polar functional groups of hydroxyl and carbonyl were introduced by UV irradiation. The water contact angle of the treated membrane was reduced from 70–75° to 10–12° after 12 h of UV exposure. Scanning electron microscopy observation showed that the dense skin layer increased as the polymer concentration increased. After UV treatment, the permeation of O2 decreased from 0.4–3.4 to 0.2–2.3 m3 m?2 h?1 bar?1, whereas that of N2, CO2, and CH4 increased for all of the pressures used from 0.1–1.7 m3 m?2 h?1 bar?1 to about 0.1–3.4 m3 m?2 h?1 bar?1; this depended on the applied pressure and the PSF content. As a result, the selectivity ratio of O2/N2 decreased from 1.9–7.8 to 0.6–1.5, whereas that of CO2/CH4 increased from 0.9–2.6 to 1.1–6.1. Moreover, the O2/N2 and CO2/CH4 of the untreated and the treated membranes decreased with increasing pressure and increased with increasing polymer concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42074. 相似文献