煤的甲烷吸附量测定方法（高压容量法）.doc

煤的甲烷吸附量测定方法(高压容量法)MTT 7521997中华人民共和国煤炭工业部19971230批准 19980601实施前言 本标准以国内新型结构类型的实验装置为基础，规定了传统的容量法测定煤的郎格缪(Langmuir)吸附等温线和解吸等温线方法，规定了统一的实验条件，保证高压甲烷吸附量测定结果的可比性和准确性。 本标准的附录A、附录B、附录C和附录D都是标准的附录。 本标准由煤炭工业部科技教育司提出。 本标准由煤炭工业部煤矿安全标准化技术委员会归口。 本标准由煤炭科学研究总院抚顺分院负责起草。 本标准主要起草人：杨思敬、宁德义、刘云生。 本标准委托煤炭工业部煤炭科学研究总院抚顺分院负责解释。1 范围 本标准规定了用高压容量法测定煤的甲烷吸附量的测定原理、测定装置、测定方法、测定步骤、精密度和结果表述等。 本标准适用于测定煤及其他吸附剂。2 引用标准 下列标准包含的条文，通过在本标准中引用而构成本标准的条文。本标准出版时，所示版本均为有效。所有标准都会被修订，使用本标准的各方应探讨使用下列标准最新版本的可能性。 GBT 2111996 煤的全水分的测定方法 GBT 2121996 煤的工业分析方法 GBT 2171996 煤的真相对密度测定方法3 测定原理 煤中大量的微孔内表面具有表面能，当气体与内表面接触时，分子的作用力使甲烷或其他多种气体分子在表面上发生浓集，称为吸附。气体分子浓集的数量渐趋增多，为吸附过程；气体分子复返回自由状态的气相中，表面上气体分子数量渐趋减少，为脱附过程。表面上气体分子维持一定数量，吸附速率和脱附速率相等时，为吸附平衡。 煤对甲烷的吸附为物理吸附。 当吸附剂和吸附质特定时，吸附量与压力和温度呈函数关系，即(1) 当温度恒定时：(2) 式(2)称为吸附等温线，在高压状态下符合郎格缪(Langmuir)方程：(3) 式(3)变换后得一直线方程：(4)式中：T温度，； P压力，MPa； Xp压力下吸附量，cm3g； a吸附常数，当p时，Xa，即为饱和吸附量，cm3g； b为吸附常数，MPa-1。4 测定装置41 实验装置 实验装置结构如图1所示。主要部件和规格如下：1玻璃活塞；2饱和食盐水量管；3真空管系；4放气阀；5真空抽气控制阀；6旋片式真空泵；7高压截止阀；8真空轨管；9吸附罐控制阀；10固态压力传感器；11吸附罐；121一电线；13复合真空计；14水浴；15高压空气阀；16充气罐控制阀；17铜管或软胶管；18超级恒温器；19充气罐；20多路信号调理器；21高压气源图1 实验装置示意图 a)吸附罐：容积50cm3，工作压力8MPa，耐压16MPa； b)高压截止阀：工作压力16MPa，耐压25MPa。密封处要求耐低压4MPa； c)固态压力传感器：测量范围为08MPa，精度为02； d)饱和食盐水量管：容积500cm3，分度5cm3，带水准瓶； e)充气罐：容积为吸附罐的14倍，耐压16MPa； f)水浴； g)真空系统：20mm40mm玻璃管，带玻璃活塞及真空硅管； h)高纯甲烷气：压力15 MPa，甲烷浓度不低于99。42 辅助设备 a)复合真空计； b)恒温器：恒温和控温01001； c)多路信号调理器：压力传感器二次仪表； d)动槽式气压计； e)标准量管；容积200cm3，分度05cm3； f)球磨机； g)干燥箱； h)标准筛； i)精密天秤，感量00001 g。5 测定方法 高压容量法测定煤的甲烷吸附量的方法是：将处理好的干燥煤样，装入吸附罐，真空脱气，测定吸附罐的剩余体积，向吸附罐中充入或放出一定体积甲烷，使吸附罐内压力达到平衡，部分气体被吸附，部分气体仍以游离状态处于剩余体积之中，已知充入(放出)的甲烷体积，扣除剩余体积的游离体积，即为吸附体积。重复这样的测定，得到各压力段平衡压力与吸附体积量，连接起来即为吸附等温线。当压力由低向高采取充入甲烷气体方式测试时，得到吸附等温线；反之，压力由高向低采取放出甲烷气体方式测试时，得到解吸等温线。吸附和解吸等温线在高压状态下是可逆的，测定二者之一，在应用上是等效的。6 测定步骤61 测定前准备工作611 煤样处理 a)采集煤层全厚样品(或分层)，除去矸石，四分法缩分成1 kg，标准采样要素，装袋，备用； b)取送样的一半全部粉碎，通过017025 mm筛网，取017025 mm间的颗粒，称出100g，放入称量皿。其余煤样分别按GBT 217、GBT 211、GBT 212测定水分(Mad)、灰分(Ad，Aad)、挥发分(Vdaf)和真密度TRD20等； c)将盛煤样的称量皿放入干燥箱，恒温到100，保持1 h取出；放入干燥器内冷却； d)称煤样和称量皿总质量G1，将煤样装满吸附罐，再称剩余煤样和称量皿质量G2，则吸附罐中的煤样质量G为：(5) 煤样可燃物质量Gr为：(6)(7)式中：Ad干燥基灰分，； Aad分析基灰分，； Mad分析基水分，。612 吸附罐体积测定 吸附罐体积(Vs)包括吸附罐体积和压力表、接头、阀门、连通管的通径体积之和。 校正方法是先将吸附罐连通真空系统，抽成压力为10Pa，关闭阀门，再接通标准量管。读取量管初始液面高度值，打开阀门，空气进入吸附罐，量管液面上升，液面上升体积值即为吸附罐容积。如此重复3次，取其平均值。613 充气罐体积测定 方法同612。614 吸附罐剩余体积测定 剩余体积(Vd)指吸附罐中除纯煤体积外包括煤颗粒内孔隙、颗粒间空隙、吸附罐残余空间和通径体积的总和。剩余体积可通过真空充氦方法标定，在没有氦气的情况下，按式(8)进行计算：(8)(9)式中：Vs空罐体积，cm3； Vc纯煤体积，cm3； TRD20样品相对真密度，gcm3。62 吸附等温线测定621 打开罐阀和真空抽气阀，关闭高压充气阀和放气阀。设定水浴温度为601，开启真空泵，进行长时间脱气，直到真空计显示压力为4Pa时，关闭真空抽气阀和各罐阀。622 设定水浴温度为试验温度(301)。623 打开高压充气阀和充气罐控制阀，使高压钢瓶甲烷气进入充气罐及连通管，关闭充气罐控制阀，读出充气罐压力值P1i。624 读出Pli后，缓慢打开罐阀门，使充气罐中甲烷气进入吸附罐，待罐内压力达到设定压力时(一般在06MPa试验压力范围内设定测，n=7个压力间隔点数，每点约为最高压力的1n)，立即关闭罐阀门，读出充气罐压力P2i、室温t1。按式(10)计算充入吸附罐内的甲烷量Qci。(10) 当使用压缩度K时式(10)为：(11)式中： Qci充入吸附罐的甲烷标准体积，cm3； P1i、P2i分别为充气前后充气罐内绝对压力(下同)，MPa； Z1i、Z2i，K1i、K2i分别为P1、P2压力下及t1时甲烷的压缩系数及压缩度，1MPa，见标准的附录A、附录B； t1室内温度，； Vo充气罐及连通管标准体积，cm3。625 保持7h，使煤样充分吸附，压力达到平衡，读出平衡压力Pi，并计算出吸附罐内剩余体积的游离甲烷量Qdi，煤样吸附甲烷量Q以及每克煤可燃物吸附甲烷量Xi。(12) 当使用压缩度K时则式(12)改为：(13) 充入吸附罐的甲烷量扣除吸附罐内剩余体积放出的游离甲烷量即为压力段内煤样吸附甲烷量Qi：(14) 每克煤压力段内的吸附量为：(15)式中：Vd吸附罐内除煤实体外的全部剩余体积，cm3； t3试验温度，； Gr煤样品可燃物质量，80626 依次重复623、624、625步骤，逐次增高试验压力，可测得，2个Qci、Qdi、Qi及Xi值。由于充气罐向吸附罐充气为逐次充入的单值量，而充入吸附罐的总气量是各单值量的累计量，故逐次按式(14)计算时，充入吸附罐的总气量Qci应是：(16) 同时，随试验压力的增高达05MPa以上后，吸附平衡时间应改为4h。627 按逐次测得的Pi及Xi作图，即为郎格缪吸附等温线，并代入式(4)用最小二乘法求得直线的斜率S(1a)和截距I(1ab)，则吸附常数为：(17)(18)63解吸等温线测定631 测定按626的最大平衡压力P1i开始，打开放气阀，关闭高压充气阀，使连通管形成常压。 用水准瓶将饱和食盐水量管充满食盐水，徐徐打开吸附罐阀门，放出一部分甲烷气进入量管(放出气量仍按最高压力的1n来控制)，关闭罐阀，读出室内大气压Pc，室温t1及量管中甲烷气体积，按式(19)计算放出甲烷气的标准体积。(19)式中：Qci放出甲烷气的标准体积，cm3； VL计量管读出的气体体积，cm3； Po室内大气压力，kPa； 002t1动槽式压力计随室温t1变化的汞膨胀性的压力校正值，kPa； Wp食盐水的饱和蒸气压，kPa，附录C。632 吸附罐在水浴中保持4h，使吸附罐内甲烷气达到吸附平衡，读出Pi2，按式20计算出该压力段罐内剩余体积的游离甲烷量Qdi。(20) 当采用压缩度K进行校正时，则式(20)为：(21) 该压力段内，放出的甲烷量扣除剩余体积中甲烷压力减少的游离甲烷，得到对应压力段下的解吸量：(22) 每克煤压力段内的解吸量为：(23)633 依次重复631、632步骤，逐次放出甲烷气和降低试验压力，可测得n-1个Qci，Qdi、Qi及Xi值。634 当测至第n点时(最后一点)，由于623测定吸附等温线的第1个平衡压力Pl不能与测定解吸等温线的第n个点的平衡压力完全重合，且第n个点测定时吸附罐中的甲烷气不可能全部放出，直到达到4Pa，故需采取插入法进行补偿，按吸附第1个平衡压力P1、吸附量Q1及解吸等温线第n个平衡压力Pn求出该压力下的吸附量Qn，同时使P1与Pn重合，即：(24)(25)635 由于62测定中为逐次向吸附罐充入气体，已按式(16)进行累加，直接取得各平衡压力Pi下对应的累计吸附量Qi或Xi，此为吸附等温线；而解吸等温线测定时是逐次放出气体，所取得的为各压力段的吸附量Qi或Xi，故需按下式进行累加，才能取得各平衡压力下对应的累计吸附量，此为解吸等温线：Qi=Qi(26)(27)636 按627绘制解吸等温线和求出a、b吸附常数。7 精密度71 压力值取2位有效数字，吸附量及郎格缪常数取4位有效数字。72 测定吸附或解吸等温线方程相关性以大于099以上，实验与计算累计偏差以小于15cm3g为合格。8 结果表述 报告中给出Pi及Xi数据、吸附或解吸等温线及吸附常数。报告格式见附录D。附录A（标准的附录）表A1 压缩系数Z值表温度05101520253035404550压力pMPaTrPr，MPa1.43251.45881.48501.51121.53741.56561.59881.61611.64361.66851.69480.10.02150.997060.997230.997420.997580.997720.997870.998010.998120.998220.998310.99840.20.04310.995210.995490.995780.996040.996270.996510.996740.996930.99710.997250.997410.30.06460.993070.993480.993890.994270.99460.994940.995270.995540.995810.996030.996280.40.08620.990760.991320.991880.992390.992820.993260.993690.994060.994420.994730.995070.50.10770.988460.989160.989870.990510.991050.991580.992120.992590.993040.993430.993860.60.12930.986150.986990.987840.98860.989250.989890.990540.99110.991640.992110.992630.70.15080.983840.984830.985820.986710.987460.988210.988970.989620.990250.99080.99140.80.17240.981530.982660.98380.984810.985670.986250.987390.988130.988850.989490.990180.90.19390.979230.98050.981780.982910.983880.984840.985810.986650.987460.988180.988951.00.21550.97690.978320.979750.981010.982090.983170.984250.985190.986080.986880.987751.10.2370.974590.976150.977730.979120.980320.98150.982700.983730.984720.98560.986551.20.25860.972260.973970.975690.977220.978530.979830.981140.982270.983350.984320.985361.30.28010.969940.97180.973670.975330.976750.978170.979590.980820.981990.983040.984161.40.30170.967620.967450.971640.973440.974960.97650.978030.979360.980620.981750.982971.50.32320.96530.965270.969620.971550.973190.974840.976480.977910.979260.980470.981771.60.34480.962970.965270.967590.969650.97140.973160.974920.976450.977890.979190.980581.70.36630.960660.963110.965560.967760.969620.97150.973370.974990.976530.977910.979381.80.38790.958330.960930.963530.965860.967840.969830.971820.973530.975160.976620.978191.90.40940.956010.958760.961520.963980.966070.968180.970280.972090.973810.975360.977012.00.43100.953680.956590.95950.96210.964310.966530.968750.970670.972480.974110.975842.10.45250.951360.954420.95750.960240.962560.96490.967230.969240.971150.972860.974682.20.47410.949020.952250.955480.958360.96080.936250.965710.967820.969810.971610.973522.30.49560.94670.95000.953480.95650.959050.961620.964190.96640.968480.970360.972362.40.51720.944370.947910.951460.954620.957290.959970.962660.964970.967140.969110.971192.50.53870.942050.945750.949450.952760.955540.958330.961140.963550.965810.967870.970032.60.56020.939720.943590.947450.950890.953790.95670.959620.962130.964480.966620.968872.70.58180.937390.941420.45430.949010.952040.955050.958090.96070.963140.965370.967712.80.60330.935070.939260.943430.947150.950290.953420.956580.959280.961820.964130.966552.90.64290.932750.93710.941430.94530.948560.951810.955080.957890.960520.962920.965433.00.64640.930430.934950.939450.943460.946830.95020.953590.95650.959220.961710.964313.10.6680.928110.932790.937450.941610.94510.948590.95210.955110.957920.96050.963193.20.68950.925790.930640.939470.939760.943380.946980.950610.953720.956630.959290.962083.30.71110.923470.928480.933470.937910.941640.945370.949120.952320.955330.958080.960953.40.73260.921160.926330.931480.936070.939920.943770.947630.950940.954040.956870.959843.50.75420.918830.924170.929490.934220.938190.9425150.946130.949540.952740.955660.958713.60.77570.916520.922020.92750.932380.936460.940550.944650.948150.951450.954450.95763.70.79730.91420.919860.92550.930530.934730.938940.943150.946760.950150.953240.956483.80.81810.911970.91780.923610.928770.93310.937420.941760.945460.948940.952110.955433.90.84040.909590.915590.921580.92690.931350.93580.940270.944080.947650.95090.954324.00.86190.90730.913470.919620.925090.929670.934240.938830.942740.946410.949740.953254.10.88350.904990.911330.917650.923270.927970.937390.937390.94140.945160.948570.952174.20.9050.90270.909210.915690.921460.926290.931110.935960.940060.943920.947410.95114.30.92660.900390.907070.913730.919650.92460.929540.934510.938720.942670.946240.950024.40.94810.898070.904930.911750.917820.92290.927970.933070.937380.941410.945070.948934.50.96970.895790.902810.90980.916020.921220.926410.931640.936050.940180.943910.947874.60.99120.893490.900680.907850.914220.919530.924850.93020.934710.938930.942750.946794.71.01280.891210.898580.905910.912430.917870.923310.928780.933390.937710.941610.945744.81.03430.888960.89650.90400.910670.916230.921790.927380.932090.93650.940490.944714.91.05590.886690.894410.902090.908910.914590.920270.925970.930790.935290.939370.943675.01.07740.884440.892330.900180.907160.912950.918750.924560.929490.934080.938250.942645.11.09890.882180.890250.898280.90540.911310.917230.923160.928190.932880.937130.941615.21.12050.879910.888160.896360.903640.909660.91570.921750.926880.931660.936010.940575.31.1420.877660.886080.894460.901880.908020.914180.920350.925580.930460.934890.939545.41.16360.875390.883990.892540.900120.906380.912660.918940.924280.929250.933770.93855.51.18510.872140.881910.890640.898360.904740.911140.917540.922980.928040.932650.937475.61.20670.870890.879840.888750.896620.903120.909640.916150.92170.926850.931550.936465.71.22820.868710.877830.886920.894950.901570.90820.914840.920480.925730.930510.935515.81.24980.866510.875820.885080.893260.90000.906760.913520.919260.92460.929460.934555.91.28130.864330.873810.883250.891590.898450.905320.91220.918040.923480.928420.93366.01.29290.862130.871790.881410.88990.896890.903880.910880.916820.922350.927370.932656.11.31440.859950.869790.879580.888230.895530.902440.909560.91560.921230.926330.931696.21.3360.857750.867770.877750.886550.893770.90100.908240.914380.92010.925280.930746.31.35750.855570.865770.875920.884870.892210.899560.906930.913160.918970.924240.929796.41.37910.853370.863750.874080.88190.890650.898120.90560.911940.917840.923190.928836.51.40060.851190.861740.872250.881510.889090.896680.90420.910720.916720.922150.927886.61.42220.848990.859730.870410.879830.887530.895240.902970.90950.915590.921110.926936.71.44370.846810.857720.868580.878150.885980.893810.901650.908280.914470.920060.925986.80.46530.844610.85570.866750.876470.884110.892360.900330.907060.913340.919020.925026.90.48680.842430.85370.864920.874790.882860.890930.899010.905840.912210.917970.924077.00.50840.840330.851770.863160.873190.881370.889550.897760.904680.911140.916980.923167.10.52990.838380.849990.861540.83170.879990.888290.89660.903620.910170.916080.922357.20.55150.836430.84820.859910.870210.878620.887020.895450.902560.909190.915180.921527.30.5730.834490.846410.858280.868730.877240.885760.89430.90150.908210.914280.92077.40.59460.832540.844620.856650.867230.875860.884490.893140.900440.907230.913380.919887.50.61610.83060.842840.855030.965750.874490.883230.891990.899380.906260.912480.919067.60.63760.828650.841060.853410.864270.873120.881970.890840.898320.905280.911580.918247.70.65920.82670.839270.851780.862770.871710.88070.889680.897260.90430.910680.917427.80.68070.824760.837480.850160.861290.870360.879430.888530.89620.903330.909780.917427.90.70230.822810.835690.848530.95980.868980.878170.887380.895140.902350.908870.91668.00.72380.850870.833910.84690.858310.867610.87690.886230.894080.901370.907980.91497附录B（标准的附录）压缩度K值表表B1P，MPa01020253040500.11.00001.03681.07381.09221.11071.14761.18450.20.99761.03451.07161.09011.10891.14631.18380.30.99520.03231.06941.08801.10711.14501.18300.40.99281.03001.06731.08591.10531.14371.18230.50.99041.02781.06511.08381.10341.14251.18160.60.98811.02551.06301.08171.10161.14121.18090.70.98571.02321.06081.07961.09981.13991.18010.80.98331.02101.05871.07751.09781.13861.17940.90.98091.01871.05651.07541.09601.13731.17871.00.97851.01641.05431.07331.09421.13611.17801.10.97611.01421.05241.07141.09231.13421.17611.20.97371.01201.05041.06961.09051.13231.17421.30.97121.00981.04841.06771.08861.13041.17231.40.96881.00761.04651.06591.08681.12851.17041.50.96651.00551.04451.06411.08491.12671.16851.60.96401.00331.04261.06221.08321.12481.16661.70.96161.00111.04061.06041.08131.12291.16471.80.95910.99881.03871.05851.07951.12101.16281.90.95670.99661.03671.05671.07761.11921.16092.00.95430.99451.03481.05491.07571.11731.15902.10.95180.99231.03281.05311.07391.11551.15722.20.94940.99011.03081.05131.07221.11381.15542.30.94710.98801.02901.04961.07041.11201.15372.40.94470.98581.02711.04781.06861.11021.15192.50.94230.938381.02521.04611.06691.10851.15012.60.93990.98161.02331.04431.06511.10671.14832.70.93750.97951.02141.04251.06331.10491.14652.80.93510.97731.01951.04081.06151.10311.14482.90.93270.97521.01761.03901.05981.10141.14303.00.93030.97311.01591.03731.05801.09961.14123.10.92790.97091.01401.03551.05631.09811.13993.20.92550.96881.01211.03381.05471.09651.13863.30.92310.96671.01011.03201.05301.09501.13733.40.92070.96451.00821.03031.05131.09371.13603.50.91840.96241.00651.02851.04971.09221.13483.60.91600.96031.00461.02601.04801.09071.13353.70.91360.95811.00271.02501.04631.08931.13223.80.91120.95611.00081.02331.04481.08781.13093.90.90880.95390.99881.02151.04311.08631.12964.00.90650.95180.99711.01981.04151.08491.12844.10.90410.94970.99531.01811.03981.08341.12704.20.91080.94770.99341.01651.03821.08281.12574.30.89950.94560.99161.01481.03661.08051.12444.40.89720.94360.98991.01321.03511.07911.12314.50.89490.94150.98821.01161.03361.07761.12184.60.89250.93950.98641.00991.03201.07621.12044.70.89020.93740.98461.00831.03041.07471.11914.80.88790.93540.98281.00661.02881.07331.11784.90.88560.93330.98101.00501.02721.07181.11655.00.88330.93130.97931.00341.02571.07041.11525.10.88100.92930.97751.00171.02411.06891.11385.20.87880.92730.97581.00011.02251.06751.11255.30.87660.92530.97400.99851.02101.06601.11125.40