温度-压力-吸附方程在计算煤岩等量吸附焓的应用

用鄂尔多斯盆地的长焰煤、肥煤、瘦煤和贫煤4个煤样的系列等温吸附实验数据来验证一个温度-压力-吸附方程,并探讨等量吸附时吸附平衡压力与温度之间的函数关系。用克劳修斯-克拉佩龙方程求等量吸附焓。提出单位等量吸附焓的概念及计算方法。结果表明：煤样等量吸附焓为负值,证实吸附过程是个放热过程;对于同一煤样,单位等量吸附焓随吸附量的增加而下降是由于吸附介质表面的能量不均匀性所造成。正因为吸附过程是个放热过程,所以吸附先发生在能量较高的位置上,以便放出更多能量;在相等吸附温度和压力条件下,高阶煤有较大的单位等量吸附焓,必有较大的吸附量。同时高阶煤吸附量随着吸附温度的升高而快速衰减,而中低阶煤吸附量衰减却没有那么明显。     

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”。     

三段逐级变压吸附浓缩煤层气的工艺设计及计算

文章提出了采用分子筛吸附剂,逐级变压吸附浓缩煤层气工艺的方法,通过三段吸附-解吸将甲烷含量10%的低浓度煤层气浓缩到甲烷含量80%。一、二级采用加压吸附、常压解吸的变压吸附工艺;三级真空解吸变压吸附运用四塔操作。对该工艺中每段所需分子筛量和分子筛的吸附容积进行了计算。     

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。     

活性炭材料变压吸附SO_2的研究

以活性炭材料作为吸附剂,通过变压技术吸附SO_2。通过BET和XPS表征分析了活性炭改性前后表面的物化性质,讨论了常压和变压条件下活性炭孔结构对SO_2吸附量的影响,发现在吸附压力0.1～0.2 MPa、吸附出口SO_2浓度不超过50 mg/m³条件下,介孔结构的活性炭材料的SO_2吸附量是常压条件下的1.79～2.79倍。考察了不同压力、不同入口SO_2浓度和含水蒸气条件对改性活性炭SO_2吸附性能的影响。变压吸附-真空脱附循环实验结果显示,改性活性炭对SO_2的变压吸附量保持稳定,具有良好的应用前景。     

煤层气吸附解吸过程采集技术研究

温度和压力是按容量法研究煤层气吸附解吸过程的两个重要物理量。其检测手段的可靠性和精确性直接决定了实验结果可信性。本文通过介绍容量法煤层气吸附解吸实验原理和温度及压力检测原理,提出了铂热电阻和硅压阻式压力传感器作为煤层气吸附解吸实验过程中对温度、压力的检测实现手段。该技术手段被用于AST-2000煤层气吸附解吸实验装置上,运行稳定,得到的结果准确,具有现实意义。     

沸石ZSM-5吸附回收低浓度煤层气中CH4

利用高硅疏水性沸石ZSM-5吸附回收低浓度煤层气中的甲烷,对其吸附平衡、吸附动力学以及真空变压吸附分离过程进行了理论和实验研究。通过重量法和穿透曲线法测定了CH₄/N₂单组分及双组分的竞争吸附平衡数据,并采用Multisite Langmuir吸附等温线模型对其进行拟合。结合CH₄和N₂稀释穿透曲线实验数据和等温无动量损失的双分散二级孔结构扩散模型,获得CH₄和N₂在沸石ZSM-5上的微孔扩散系数。建立并求解包含质量、动量及能量传递的固定床吸附分离模型方程,预测了CH₄和N₂在沸石ZSM-5上的竞争吸附穿透曲线。进一步采用ZSM-5吸附剂填充床单柱四步真空变压吸附实验考察了进料浓度、进料流速、进料时间以及吹扫比对分离效果的影响。结果发现沸石ZSM-5对CH₄具有较好的选择性,沸石晶粒内的微孔扩散为吸附速率控制步骤,真空变压吸附工艺可将模拟煤层气中20%的CH₄提纯至31%～41%,回收率为93%～98%。     

交变电场作用下煤吸附甲烷特性的研究

对交变电场作用下煤吸附／解吸甲烷特性进行了研究。结果表明：交变电场作用下：各煤样吸附甲烷的量仍很好地遵从Ｌａｎｇｍｕｉｒ方程,交变电场的作用减弱了煤的吸附能力和解吸能力,并且减缓了含甲烷煤的解吸过程,但对煤的饱和吸附量和最大解吸量影响不大。     

吸附热预测吸附等温线

实验测定了N2 在沸石分子筛、C2 H6 在活性炭、CO2 在硅胶上的吸附等温线 ,研究用Clausius Clapeyron方程求得等量吸附热、再利用所得的吸附热预测其它温度的吸附等温线数据的方法。将吸附热预测的等温线与实验值及插值法内插得到的吸附等温线数据进行了比较 ,结果表明吸附热预测值与实验值吻合较好。此外还对文献数据利用等量吸附热预测较高压力 ( 65 0kPa)下的等温线 ,均与文献中的实验值一致。为吸附工业操作需要不同温度下的等温线数据和吸附过程的模拟与设计提供了简便、准确的计算方法     

变压吸附回收乙烯的方法

专利申请号：200410013825.3公开号：CN 1555905申请日：2004-01-07公开日：2004-12-22申请人：扬子石油化工股份有限公司一种变压吸附回收乙烯的方法,利用具有选择性吸附的吸附剂,采用变压吸附技术,在一定的温度和较高的压力下选择吸附混合气体中一种或一种以上强吸附组分,排放不吸附或弱吸附的组分。包括吸附、排放、脱附及升压等过程。所述的吸附剂为分子筛,吸附过程的压力范围为0～36bar、温度范围为     

基于DA模型的煤表面甲烷吸附线预测

采用高低温甲烷吸附解吸测试系统,在243.15, 263.15, 283.15, 303.15和323.15 K下用不同变质程度的煤(气肥煤、焦煤、贫煤和无烟煤等)对甲烷进行等温吸附,基于微孔填充Dubinbin?Astakhov(DA)模型对其它环境温度下煤的CH4吸附等温线进行预测. 结果表明,不同变质程度的煤对甲烷的吸附量均随温度降低而增大,且饱和吸附量和特征吸附能与温度具有良好的线性关系. 模型预测的等温吸附曲线与实验结果吻合较好,相对误差不超过5%.     

煤粉炉和循环流化床锅炉飞灰吸附汞动力学及其吸附机制

在固定床吸附反应器内对两台300MW等级燃煤发电机组循环流化床锅炉和煤粉锅炉飞灰样品进行气相零价汞吸附实验,通过改变实验工况研究温度、入口汞浓度和入口气体流量对飞灰汞吸附能力的影响。采用颗粒内扩散模型、准一阶和准二阶动力学模型、耶洛维奇（Elovich）模型对实验数据分别进行拟合,从动力学的角度探讨两种锅炉飞灰对气相零价汞吸附的影响机制以及两种锅炉飞灰与气相零价汞之间吸附动力学行为差异。结果表明：相同工况下循环流化床锅炉飞灰汞吸附过程的穿透时间和平衡吸附量远大于煤粉锅炉飞灰。吸附温度为150℃时,两种锅炉飞灰对气相零价汞的平衡吸附量最大。由于外扩散阻力随气体入口流量的增加而减小,入口汞浓度的增加可提高传质推动力,飞灰对汞的吸附得以增强。动力学分析表明飞灰的零价汞吸附由外扩散、内扩散和表面化学吸附共同控制,其中表面化学吸附是该吸附过程中的控制步骤;准二阶动力学模型和Elovich动力学模型更适合于描述该吸附过程。相同实验条件下,循环流化床锅炉飞灰吸附过程拟合所得的颗粒内扩散系数、准一阶动力学常数和初始吸附速率均大于煤粉锅炉飞灰。     

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.     

Predictive equations in gas adsorption kinetics

The experimental method of determining the operative parameters of adsorptive capacity and rate in the gas adsorption kinetics of packed bed sorbents relies upon the linear relationship between gas breakthrough time and sorbent weight. The slope and intercept of the straight line, resulting from such a plot, yields values for the gas saturation capacity and adsorption rate constant of the adsorbent. This relationship is shown in the modified Wheeler adsorption equation, originally derived from a continuity equation of mass balance between the gas entering an adsorbent bed and the sum of the gas adsorbed by plus that penetrating through the bed. We have found that for wellpacked adsorbent beds, the Dubinin-Polanyi equations for predicting adsorption space at equilibrium, based upon prior characterization of an adsorbent with a reference gas, could also be applied to gas flow conditions, and the kinetic capacity of the adsorbent predicted within close limits. Although no theoretical relationship exists for prediction of the adsorption rate constant, recent gas tests at high linear flow velocities have shown experimental evidence of the mass transfer limiting value for the rate constant. The functionalities of the kinetic saturation capacity and the mass transfer limited value for the adsorption rate constant have been incorporated into the modified Wheeler adsorption equation to provide an expanded equation permitting prediction by calculation of the breakthrough time of a gas through a well-packed bed of adsorbent granules.     

Process characteristics investigation of simulated circulating fluidized bed combustion combined with coal pyrolysis

A poly-generation process of simulated circulating fluidized bed (CFB) combustion combined with coal pyrolysis was developed in a laboratory scale. Pyrolysis characteristics of three bituminous coals with high volatile contents were investigated in a fixed bed with capacity of 10 kg solid samples. The effects of initial temperature of solid heat carrier, pyrolysis holding time, blending (ash/coal) ratio and coal particle size on gas and tar yields were studied experimentally. The results indicate that the initial temperature of the heat carrier is the key factor that affects the gas and tar yield, and the gas composition. Most of the gas and the tar are released during the first few minutes of the pyrolysis holding time. For caking coal, the amount of char agglomerating on the pyrolyzer inner wall is reduced by enhancing the blending ratio. The experimental results may provide basic engineering data or information for the process design of CFB combustion combined with coal pyrolysis in a large scale.     

Breakthrough Analysis for Adsorption of Phosphine on 5A Molecular Sieve

Adsorption experiments were carried out under dynamic conditions for the removal of phosphine (PH₃) in nitrogen on a fixed bed of 5A molecular sieve. The experiments were conducted to characterize the breakthrough characteristics of PH₃ in the fixed bed under different operating conditions, including bed temperature, bed mass, and initial PH₃ concentration. A mathematical model was developed to predict the breakthrough profiles of PH₃ during adsorption on the 5A molecular sieve. The model was successfully validated with the observed experimental breakthrough data, showing that the adsorption capacity increases with decreasing temperature and with rising phosphine concentration in the gas mixture. The study showed the potential application of 5A molecular sieve in controlling PH₃ emission.     

活性炭吸附脱硫固定床反应器研究

在原油储运过程中挥发的H2S这种恶臭气体不但危害人体健康,还对环境造成很大的污染。文章提出了采用活性炭吸附脱除原油挥发气中H2S的工艺。从理论上探讨了活性炭脱硫机理及固定床内吸附传质动力学,并且建立了活性炭吸附H2S的固定床脱硫反应器数学模型,采用COMSOL Multiphysics软件求解数学模型以预测穿透曲线。同时进行了实验研究,并根据实验数据绘出了穿透曲线,且与模型计算结果进行了比较,二者吻合较好。还进一步探讨了空速、温度和原料气含量对吸附硫容的影响。     

基于低场核磁共振的煤粉动态吸附测量

煤层气的开发是我国非常规天然气开发的重要环节，与常规天然气不同的是煤层气中甲烷主要以吸附形式赋存在煤的一系列纳米孔中。甲烷在煤粉颗粒孔隙中吸附行为的动态过程对煤层气的开发具有重要意义。实现了一种基于低场核磁共振技术在线测量煤粉吸附特性的实验方法，通过横向驰豫分布区别孔隙中含氢流体分布，定量表征游离气和吸附气含量。结果表明煤粉颗粒的甲烷吸附在核磁共振的横向弛豫图谱中呈现多峰分布，其中弛豫时间在0.1～1 ms的峰包含了纳米孔隙中甲烷含气量的信息。随着时间增加，甲烷气体逐渐转换为吸附态。通过不同压力下核磁共振的横向弛豫图谱，定量分析了甲烷在颗粒样品中随时间和压力变化的动态吸附过程，并得到了等温吸附曲线且符合Langmuir拟合模型。