基于GAI-100吸附装置煤吸附甲烷气体实验的分析

基于GAI-100高压等温吸附装置对煤吸附甲烷气体实验进行分析,通过测试多组实验数据,结合黔北地区煤的吸附性和相关结构特征,对该地区煤吸附甲烷特征进行测试,通过高压容量法分析煤在不同压力和温度下的吸附特性.     

恒电场作用下煤吸附甲烷特征的研究

研究了四川白皎低变质无烟煤在直流１ ２００ Ｖ 下吸附甲烷的特征．结果表明：外加电场作用下煤吸附甲烷仍符合Ｌａｎｇｍ ｕｉｒ 等温吸附式, 吸附与解吸的动力学也符合三常数扩散控制模型和二常数经验公式; 恒电场使煤对甲烷的吸附能力降低 （ｂ 常数减小）, 但对动力学参数的影响不大．     

中煤级煤甲烷饱和吸附量的数值模拟计算

根据表征中煤级煤（镜质组最大反射率R_o,max=0.65%～2.50%）的系列等温吸附（20℃、30℃、40℃和50℃这4个实测温度）“煤变质程度-压力-吸附量”的三变量数学方程,建立一组“煤变质程度-温度-压力-吸附量”这4个共同存在并相互影响的四变量数学方程。该四变量数学方程用于预测1200m以浅的中煤级煤甲烷饱和吸附量。这种数学转换的平均相对误差在7.28%～9.49%之间。有处理中煤级煤甲烷饱和吸附量的数值模拟的软件著作。只要将5个实测数据：镜质组最大反射率R_0,max、温度梯度、压力梯度、埋深和恒温层温度,输入相应可编辑文本框中,就可以输出5个值：饱和吸附量V、温度-压力-吸附量方程中的参数（A、B、Δ、β）。还可以输出在自己感兴趣的镜质组最大反射率R_0,max、温度梯度、压力梯度、埋深和恒温层温度下,“R_0,max值时温压吸附曲面”和“吸附量随埋深变化图”。     

原生煤和构造煤的吸附等量线比较及与瓦斯突出的关系研究

根据温度—压力—吸附方程及其相关变换方程,将沁水盆地大宁煤矿的原生煤和构造煤系列等温吸附实验数据,转换成可进行热力学相关比较和计算的吸附等量线;在对甲烷气体相同吸附量下,原生煤吸附等量线的温度、压力升速大于构造煤;随着吸附量的增加,原生煤的吸附等量线与构造煤的吸附等量线相交;交点之前,在相同吸附量和相同温度下,构造煤(小坚固性系数)的吸附压力大于原生煤(大坚固性系数)的吸附压力;交点之后,在相同吸附量和相同压力下,构造煤的平衡温度高于原生煤;在吸附量都为35 cm~3/g时,原生煤的单位等量解吸热为0.835 kJ·g/(mol·cm~3),比构造煤多吸热0.204 kJ·g/(mol·cm~3);相较于原生煤,构造煤优先解吸瓦斯;研究认为煤与瓦斯突出最容易发生在构造煤。     

变温变压下煤层气吸附量的预测

等温吸附虽然被大量学者进行研究并用于煤层气储量的预测,由于其实验条件不符合实际开采过程中的地温与地压,故很多专家提出用变温变压的实验条件来预测煤层气的吸附量,但是到目前为止鲜有很好的方程来处理变温变压实验数据。本文基于煤炭科学研究总院西安研究院张庆玲对4种不同煤级煤样在变温变压吸附实验的研究,提出了温度-压力-吸附量方程（TPAE方程）用于煤层气在温度和压力共同影响下吸附量的预测。通过TPAE方程,对4种不同煤级在变温变压下吸附量进行回归预测。结果表明：TPAE方程可以非常好地处理变温变压吸附实验数据,4种煤样的回归计算值与实测值最大平均相对误差为2.64%,最小为1.63%,同时实现温度和压力及吸附量三维视图的可视化,从图中可知任意温度和压力下煤层气的吸附量。     

煤的原子分子结构及吸附甲烷机理研究进展

总结了煤的原子径向分布与微晶结构、稠环芳烃的电子光谱规律与煤的颜色间的关系、煤与CH4分子的相互作用、无烟煤及其炭化样吸附／解吸甲烷的热力学和动力学过程等内容的研究与发展，结果表明：(1)低阶煤的微晶参数d002，Ic和Ia随含碳量呈阶段性变化，其微晶结构特征与纤维素的结构有关，并可用煤化度p定量描述煤化过程中煤的微晶结构变化。(2)煤中存在13个苯环以上稠环芳香结构单元，(3)甲烷分子与煤表面的相互作用各向异性，最大作用势(吸附势)为2．65kJ／mol，旋转势垒为1．34kJ／mol，预计吸附振动光谱的跃迁基频为53cm^-1。(4)煤对甲烷的饱和吸附量几乎不随温度变化，炭化样与活性炭的饱和吸附量则随温度的降低而线性增大；从煤制备的炭化样，以及活性炭的吸附热都接近甲烷液化热，而煤的吸附热则高出近一倍。(5)煤层(粒)吸附解吸甲烷的动力学过程可用通用的一级组合模型和实用的吸附(解吸)扩散控制模型来描述，其三常数动力学公式中的初始吸附(解吸)率Q0／Qmax可作为煤与瓦斯突出预测指标。(6)甲烷在无烟煤中的扩散系统为～10^-10cm^2／s，扩散活化能为14．3kJ／mol；甲烷在煤中的扩散实为通过微孔的流动。     

羊骨基活性炭对溶液中Pb(Ⅱ)的吸附性能

采用本实验室自制的羊骨基活性炭,研究其在不同吸附时间、不同溶液初始浓度、不同投加量、溶液不同的pH值条件下对Pb(Ⅱ)的吸附规律。结果表明:当Pb(Ⅱ)溶液的初始浓度为80mg/L、活性炭投加量为0.10g、吸附时间为6h、溶液温度为45℃时,羊骨基活性炭对Pb(Ⅱ)的去除率高达99%。利用Langmuir吸附等温模型和Freundlich吸附等温模型对其吸附性能的表征得出:羊骨基活性炭对溶液中Pb(Ⅱ)的吸附行为符合Langmuir吸附等温模型和Freundlich吸附等温模型,并且吸附等温曲线在Brunauer五种类型的等温吸附线中比较符合多分子层吸附等温线。     

中低煤阶镜煤/暗煤大分子结构及对甲烷吸附的影响

为研究中低阶煤不同宏观煤岩组分微观结构及对甲烷吸附的影响，采集黄陇煤田郭家河、大佛寺、园子沟及黄陵矿区的四种不同煤样，手工剥离不同宏观煤岩成分(镜煤和暗煤),通过傅立叶红外光谱(FTIR)分析、X射线衍射(XRD)分析和等温吸附实验探究中低阶煤分子结构特征及其对甲烷吸附能力的影响。结果表明：同一煤样中镜煤的水分和挥发分产率高于暗煤的水分和挥发分产率，而暗煤的灰分产率和固定碳含量高于镜煤的灰分产率和固定碳含量。镜煤的显微组分中镜质组含量较大、惰质组含量较低，暗煤则相反。红外光谱分析结果表明，同一煤层的镜煤和暗煤红外光谱吸收峰形态相似，官能团类型和含量接近。煤分子结构中主要含氧官能团按含量由高到低依次为C—O,COOH,■,脂肪侧链按含量由高到低依次为CH₂,CH₃,CH。对比煤的准晶体结构发现，中低阶煤煤化程度低，γ带的峰面积整体较大。受煤化作用和压实作用影响，暗煤的堆砌度和堆砌层数大于镜煤的堆砌度和堆砌层数。分子结构特征对甲烷吸附量的影响显著。镜煤的最大甲烷吸附量与芳碳率和缩合度均呈正相关，暗煤的最大甲烷吸附量与芳碳率和缩合度均呈负相关。镜煤...     

不同变质变形煤热解气相产物H_2的逸出特征

通过对三种不同变质程度(Ro,max=0.38%~1.06%)原生结构煤和三种不同变形类型(弱脆性变形、强脆性变形和强韧性变形)构造变形煤的热解实验,探讨了不同变质、变形煤热解过程中H2的逸出特征.结果表明,三种不同变质程度原生结构煤(SGT01,JZT01和WY01)热解过程中H2的逸出量随温度增加(600℃~800℃)具有一定的差异,但三者热解H2累积生成量变化不大.在相同的温度下,三种不同类型构造变形煤(XTM09,XTM07和XTM10)热解中H2的逸出量差异明显,变形程度较强的强韧性变形煤(XTM10)和强脆性变形煤(XTM07)热解H2产出速率和累积生成量均明显小于变形程度较弱的弱脆性变形煤(XTM09);强韧性变形煤(XTM10)热解H2产出速率和累积生成量又明显低于强脆性变形煤(XTM07).     

煤吸附常数的影响因素分析

通过对烟煤和无烟煤各煤级173个煤样的平衡水分、灰分、挥发分产率、显微组分、镜质体反射率和吸附常数的综合研究,探讨了煤吸附常数的影响因素,揭示了不同影响因素条件下等温吸附常数的变化规律。结果显示:煤变质程度相近时,平衡水分含量增加,灰分(干基)含量增加,温度升高,吸附常数a有线性下降的趋势。a值与烟煤和无烟煤的镜质组含量及镜质组反射率呈一定的正相关趋势,与挥发分产率呈一定的负相关趋势。b值与烟煤和无烟煤的镜质组反射率呈一定的负相关趋势。各煤级吸附常数a平均值呈较好一次正相关线性关系,吸附常数b平均值呈较好的二次负相关线性关系。     

高压下煤对CH4/CO2二元气体吸附等温线的研究

研究了晋城和潞安煤在高压下对纯 CH4,CO2 及其二元混合气体的吸附特性 ,在对混合气体绝对吸附量计算公式推导的基础上 ,对绝对吸附等温线进行了研究 .结果表明 :高压下煤对混合气体的吸附介于纯 CH4和 CO2 之间 ,Gibbs吸附等温线和绝对吸附等温线表现出较大的差异 ;煤对混合气体中 CH4和 CO2 的吸附呈现出不同的吸附特点 ;煤对 CO2 优先吸附 ,并且随着压力的升高 ,煤对 CO2 选择性吸附能力增加 .本研究结果对开展注烟道气提高煤层采收率和煤层埋藏CO2 具有一定的指导作用 .     

沁水盆地重点区块煤储层吸附特征及影响因素

煤储层吸附特征参数是评价煤层气资源和开发潜力的重要参数,煤储层的吸附能力是影响煤层气含量的关键因素之一,也直接影响煤层气井的产能,因此研究煤储层的吸附特征、分析煤储层吸附能力的影响因素对于煤层气的开发具有重要意义。根据等温吸附试验结果,对沁水盆地某区块煤储层的吸附特征进行研究,并探讨煤储层吸附能力的影响因素。结果表明:该区块含气量高,具有较强的吸附能力。煤阶、孔隙率、灰分和煤体结构对煤储层吸附能力有较大影响;孔隙率越大、煤体结构越完整,煤储层吸附能力越强;灰分的增加会降低煤的吸附能力;随煤阶的增加,煤储层吸附能力先增加后减小。     

Zn/Cr水滑石吸附-可见光催化水中有机污染物

通过共沉淀法合成可循环使用的阴离子粘土材料锌铬水滑石(Zn/Cr LDHs),并借助X射线衍射(XRD),N2吸附-脱附曲线,扫描电子显微镜(SEM)和紫外-可见光漫反射光谱(DRS)等对其进行表征分析。以刚果红为模型污染物,研究了Zn/Cr LDHs去除有机污染物的吸附-可见光光催化活性。通过等温吸附试验,得到Langmuir等温线,其饱和吸附量为426.29 mg/g。Zn/Cr LDHs在氙灯模拟太阳光照射下,每次试验180 min,第5次后脱色率仍高达96.35%,具有良好的可循环使用性。刚果红吸附等温线符合Langmuir模型,吸附过程符合拟二级动力学模型,内扩散为主要控速步骤,吸附过程是自发的放热过程,低温有利于吸附的进行。     

Adsorption of methane on corn cobs based activated carbon

Activated carbon was prepared with corn cobs and potassium hydroxide under optimized variables. Due to their botanical origin, corn cobs can be an excellent starting material to produce nanoporous carbon for natural gas storage. Samples with different BET surface areas were chosen to perform methane adsorption experiments. Methane adsorptions on corn cob based activated carbon were studied at four different pressures (500, 1000, 1500 and 2000 psi) and two different temperatures (298 K and 323 K) in a volumetric adsorption apparatus. The volume based methane adsorption results specified an ‘increase in the methane adsorption capacities of activated carbon with increasing surface area and showed that adsorption capacity of methane depends on pressure and temperature. The highest methane storage capacity was found to be 160 (v/v) at 298 K and 1500 psi. The applications include use in the transportation of natural gas, natural gas based vehicles, and adsorption of gas from landfills.     

Calculation of single adsorption isotherms from gravimetrically measured binary gas mixture adsorption isotherms on activated carbon at high pressures

A method is developed for the calculation of single-component adsorption isotherms from gravimetrically measured binary gas mixture adsorption isotherms at high pressures, at two temperatures and for different mole fractions of the gas phase. The adsorption of nitrogen/methane on active carbon Norit R1 is taken as an experimental example.     

In-situ temperature-depth profile evaluation of South African unmineable coal seams to determine CO2 sequestration potential

This study aimed to investigate the sorption behaviour of South African coal seams with relation to the effect of temperature during CO₂ sequestration. The excess adsorption isotherms of CO₂ adsorption were undertaken using a high-pressure volumetric system for four coals of different coal rank (denoted by Somkele [SK], anthracite KZN [AN], Tshikondeni [TD], and Syferfontein [SF]). The volumetric pressure step method was conducted at increments of system temperature of 35, 45, 55, and 65°C for pure CO₂ adsorption at incremental pressures up to 93 bar. The results showed that high temperatures have a very significant negative effect on the amount of CO₂ adsorbed on the coal samples. The high-rank coal samples (SK and AN) demonstrated elevated CO₂ adsorption capacity across all tested temperatures due to their high vitrinite content. The medium-rank coals (TD and SF) exhibited comparatively lower CO₂ adsorption capacity, attributed to the presence of adsorption hindrances such as higher ash content and volatile and mineral matter. The isosteric heat of adsorption revealed an increasing trend with coverage for all coal samples, with higher rank coals displaying greater slopes. The determined range of the isosteric heat of adsorption, spanning from 10 to 59 kJ/mol, indicated that the adsorption process is primarily of a physisorption nature. Three theoretical models (Langmuir, Freundlich, and Temkin) were evaluated and fitted to the sorption experimental data. The Temkin model exhibited superior fitting compared to the Langmuir and Freundlich isotherms. The Temkin isotherm parameters suggest that the adsorption of CO₂ onto coal is a physisorption process.     

Thermodynamic adsorption data of CH4, C2H6, C2H4 as the OCM process hydrocarbons on SAPO-34 molecular sieve

Adsorption of CH₄, C₂H₆ and C₂H₄, the feed and main products of oxidative coupling process of methane (OCM) has been studied on silicoalumina-phosphate molecular sieve (SAPO-34) in mild conditions. The experiments were conducted in a batch system based on volumetric adsorption measurement technique for determination equilibrium adsorption capacity in the absolute pressure range of 100–1000 kPa and at the isothermal temperatures of 303, 313 and 323 K. Various isotherm equations were fitted on the adsorption equilibrium data and the model parameters were predicted as a function of temperature. Isosteric heats of adsorption were determined using Clausius–Clapeyron equation at different surface coverage. Maximum capacity of SAPO-34 was observed at 303 K and 880–900 kPa equilibrium pressure with 1.25, 2.02 and 4.67 mmol/g adsorbed amount for methane, ethane and ethylene adsorption, respectively. The adsorption selectivity of ethane and ethylene against methane were determined and the appropriate potential of SAPO-34 was observed for separation of OCM products from methane. The isotherm models and enthalpy of adsorption can be efficiently used for the simulation of the adsorption process constructed at the downstream of the OCM process for separation of ethane and ethylene from methane.     

Assessment of energetic heterogeneity of coals for gas adsorption and its effect on mixture predictions for coalbed methane studies

This study explains the single-component and binary mixture adsorption studies on two different coals from the Zonguldak Basin (Northwestern Turkey). Assessment of energetic heterogeneity of coal surface and its effect on the equilibrium binary gas adsorption are discussed. Single component adsorption tests were performed using methane and carbon dioxide at 30°C. Binary mixtures prepared with 10, 15 and 20% carbon dioxide were also tested at the same temperature. Various single-component adsorption isotherms were fitted to the experimental data of single gases. The data obtained from these models were interpreted to determine the energetic heterogeneity of the coals towards adsorption of methane and carbon dioxide. Ideal adsorbed solution (IAS) theory was used to predict the data and discrepancies between experimental data, and the model predictions were interpreted. Results showed that coals exhibit a heterogeneous behavior in gas adsorption. This heterogeneity can be different for each coal–gas pair and the extent of the heterogeneity makes the binary gas predictions differ from the experimental data. The deviations between IAS and experimental data increase as the amount of gas, to which the coal shows high heterogeneity, increases in the mixture.     

Experimental study and artificial neural network simulation of methane adsorption on activated carbon

The adsorption of methane on two activated carbons with different physical properties was measured. Adsorption isotherms were obtained by static volumetric method at different temperatures and pressures. The experimental results sow the best gas storage capacity was 113.5 V/V at temperature 280 K and pressure 8.5MPa on an activated carbon with surface area 1,060 m²/gr. An artificial neural network (ANN) based on genetic algorithm (GA) was used to predict amount of adsorption. The experimental data including input pressure, temperature and surface area of adsorbents as input parameters were used to create a GA-ANN simulation. The simulation results were compared with the experimental data and a good agreement was observed. The simulation was applied to calculate isosteric heat of adsorption by using the Clausius-Clapeyron equation. Comparison of the calculated adsorption heat showed different surface heterogeneity of the adsorbents.