季铵盐对煤层气水合物生成影响的实验及理论研究

发布时间：2018-04-23 19:40

  本文选题：水合物 + 煤层气　； 参考：《太原理工大学》2017年硕士论文

【摘要】：随着工业的迅猛发展,我国对能源的需求日益增加,经济增长与能源供需、环境的矛盾日益突出。为响应“节能减排,低碳经济”的号召,天然气利用比重逐年增加。煤层气属于非常规天然气,在我国储量丰富,但由于利用不合理和技术的限制,煤层气排放量逐年递增,资源浪费严重,同时加重了温室效应。合理、高效、安全利用煤层气迫在眉睫。水合物法利用煤层气中各组分相平衡条件不同分离提纯低浓度煤层气,相比传统的分离技术有其独有的优势。目前水合物法工业应用存在相平衡压力高、诱导时间长、储气率低下等问题,为克服这些障碍,国内外学者对水合物生成的热力学以及动力学促进剂进行了广泛的研究,发现了如十二烷基硫酸钠(SDS)、四氢呋喃(THF)等性能优良的促进剂。季铵盐是常见的表面活性剂,大量研究表明四丁基溴化铵(TBAB)、四丁基氯化铵(TBAC)和四丁基氟化铵(TBAF)对气体水合物同样具有优良的热力学和动力学促进效果。鉴于此,本文选用TBAC、TBAF、四甲基溴化铵(TMAB)、四甲基氯化铵(TMAC)和四甲基氟化铵(TMAF)五种季铵盐,实验研究了各季铵盐对低浓度煤层气(CBM,摩尔分数为30%CH_4+65%N2+5%O2)热力学和动力学的影响,研究因素包括水合物的相平衡条件、相变潜热、诱导时间以及储气率;并使用修正的水的逸度模型对TBAB、TBAC和TBAF与纯甲烷及煤层气水合物相平衡进行了模拟。具体工作内容如下:(1)实验研究了TBAC、TBAF以及TMAB、TMAC、TMAF在内的5种季铵盐对低浓度煤层气水合物形成的热力学和动力学影响,浓度均涉及0.17、0.29、0.62、1.38以及3.5 mol%五种,采用恒容压力搜索法获得水合物相平衡数据,相平衡温度282.3~304.5 K,相平衡压力0.919~8.435 MPa,季铵盐浓度对水合物促进作用呈现非线性,存在最佳浓度,本实验最佳促进浓度排序为:3.5 mol%TBAF0.62 mol%TMAF3.5 mol%TBAC1.38mol%TMAB1.38 mol%TMAC;使用Clausius-Clapeyron获取季铵盐气体水合物的相变潜热,排序为:3.5mol%TBAF0.62mol%TMAF3.5mol%TBAC1.38 mol%TMAB1.38 mol%TMAC;获得诱导时间数据,排序为:3.5 mol%TBAF3.5 mol%TBAC1.38 mol%TMAC≈1.38 mol%TMAB0.62 mol%TMAF;计算得季铵盐水合物储气率,总体上TBAC储气率高于TBAF。(2)采用修正的水的逸度模型描述水合物相行为,PRSV2状态方程计算气体组分逸度,e-NRTL电解质活度系数模型计算季铵盐溶液各组分活度系数。修正的水的逸度模型对季铵盐与单组份气体水合物相平衡模拟效果欠佳,平均相对误差在15%以下;对TBAX与煤层气水合物相平衡模拟效果较好,平均相对误差在9%以下,为季铵盐应用于水合物法分离煤层气提供了理论依据。
[Abstract]:With the rapid development of industry, the demand for energy in China is increasing day by day, and the contradiction between economic growth and energy supply and demand and environment is becoming more and more prominent. In response to the call of "energy saving and emission reduction, low-carbon economy", the proportion of natural gas utilization is increasing year by year. Coal bed methane (CBM) is a kind of unconventional natural gas, which is rich in reserves in our country. However, due to unreasonable utilization and technical limitation, CBM emissions are increasing year by year, resources are wasted seriously, and Greenhouse Effect is aggravated at the same time. Rational, efficient and safe use of coalbed methane is imminent. The method of hydrate is used to separate and purify low concentration CBM by using different equilibrium conditions of each component in CBM, which has its unique advantages compared with the traditional separation technology. At present, there are some problems in the application of hydrate method, such as high phase equilibrium pressure, long induction time, low gas storage rate and so on. In order to overcome these obstacles, domestic and foreign scholars have carried out extensive research on thermodynamics and kinetic accelerators for hydrate formation. Excellent accelerators, such as sodium dodecyl sulfate (SDS), tetrahydrofuran (THF), were found. Quaternary ammonium salts are common surfactants. A large number of studies have shown that tetra ammonium bromide (TBABN), tetra- ammonium chloride (TBACN) and tetra ammonium fluoride (TBAFs) also have excellent thermodynamic and kinetic effects on gas hydrates. In view of this, five quaternary ammonium salts, TBAC, TMAB, TMAC and TMAF) were selected. The effects of quaternary ammonium salts on the thermodynamics and kinetics of low concentration CBM in 30%CH_4 65%N2 5O2 were studied experimentally. The research factors include the phase equilibrium condition of hydrate, latent heat of phase transition, induction time and gas storage rate, and the modified fugacity model of water is used to simulate the phase equilibrium of TBABN TBAC and TBAF with pure methane and coal-bed methane hydrate. The thermodynamic and kinetic effects of five quaternary ammonium salts, including TBACU TBAF and TMABX TMACU TMAF, on the formation of low concentration coal-bed methane hydrates were studied. The concentrations of these quaternary ammonium salts were 0.170.290.290.62% 1.38 and 3.5 mol%, respectively. The phase equilibrium data of hydrate were obtained by constant volume pressure search method. The phase equilibrium temperature was 282.3n 304.5 K, the phase equilibrium pressure was 0.919 ~ 8.435 MPa, and the concentration of quaternary ammonium salt was nonlinear and the best concentration existed. 鏈�瀹為獙鏈�浣充績杩涙祿搴︽帓搴忎负:3.5 mol%TBAF0.62 mol%TMAF3.5 mol%TBAC1.38mol%TMAB1.38 mol%TMAC;浣跨敤Clausius-Clapeyron鑾峰彇瀛ｉ摰鐩愭皵浣撴按鍚堢墿鐨勭浉鍙樻綔鐑，

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