化工学报
化工學報
화공학보
JOURNAL OF CHEMICAL INDUSY AND ENGINEERING (CHINA)
2014年
10期
3946-3952
,共7页
离子交换%Y型分子筛%吸附%脱附%分离
離子交換%Y型分子篩%吸附%脫附%分離
리자교환%Y형분자사%흡부%탈부%분리
ion-exchange%Y-type zeolite%adsorption%desorption%separation
用CaCl2、La(NO3)3和Ce(NO3)3溶液对NaY分子筛进行离子改性制备出CaY、LaY和CeY分子筛。将其及NaY为吸附剂，利用动态吸附法评价其吸附分离1,1,1,2-四氟乙烷（HFC-134a）产品中微量1,1-二氟-2-氯乙烯（HCFC-1122）的性能。同时采用X射线衍射（XRD）、吡啶红外（FTIR）和氨-程序升温脱附（NH3-TPD）等手段对新鲜及再生后的吸附剂进行结构和表面性质表征。结果表明：CaY、LaY与CeY分子筛上的Br?nsted酸中心可与HCFC-1122形成π-吸附配合物，从而将吸附流出气中HCFC-1122的残余率降低至1.0%以下；Br?nsted酸强度越高，π-吸附配合物越容易形成，最低吸附温度越低（CeY＜LaY＜CaY)。220℃下穿透吸附容量随CaY＜LaY＜CeY增加，归因于较少的强Br?nsted酸和弱Lewis酸数量有利于HCFC-1122的π-吸附配合物引发程度较低的聚合反应。吸附剂的热脱附再生性能不佳与其表面酸中心覆盖物难以脱除有关。
用CaCl2、La(NO3)3和Ce(NO3)3溶液對NaY分子篩進行離子改性製備齣CaY、LaY和CeY分子篩。將其及NaY為吸附劑，利用動態吸附法評價其吸附分離1,1,1,2-四氟乙烷（HFC-134a）產品中微量1,1-二氟-2-氯乙烯（HCFC-1122）的性能。同時採用X射線衍射（XRD）、吡啶紅外（FTIR）和氨-程序升溫脫附（NH3-TPD）等手段對新鮮及再生後的吸附劑進行結構和錶麵性質錶徵。結果錶明：CaY、LaY與CeY分子篩上的Br?nsted痠中心可與HCFC-1122形成π-吸附配閤物，從而將吸附流齣氣中HCFC-1122的殘餘率降低至1.0%以下；Br?nsted痠彊度越高，π-吸附配閤物越容易形成，最低吸附溫度越低（CeY＜LaY＜CaY)。220℃下穿透吸附容量隨CaY＜LaY＜CeY增加，歸因于較少的彊Br?nsted痠和弱Lewis痠數量有利于HCFC-1122的π-吸附配閤物引髮程度較低的聚閤反應。吸附劑的熱脫附再生性能不佳與其錶麵痠中心覆蓋物難以脫除有關。
용CaCl2、La(NO3)3화Ce(NO3)3용액대NaY분자사진행리자개성제비출CaY、LaY화CeY분자사。장기급NaY위흡부제，이용동태흡부법평개기흡부분리1,1,1,2-사불을완（HFC-134a）산품중미량1,1-이불-2-록을희（HCFC-1122）적성능。동시채용X사선연사（XRD）、필정홍외（FTIR）화안-정서승온탈부（NH3-TPD）등수단대신선급재생후적흡부제진행결구화표면성질표정。결과표명：CaY、LaY여CeY분자사상적Br?nsted산중심가여HCFC-1122형성π-흡부배합물，종이장흡부류출기중HCFC-1122적잔여솔강저지1.0%이하；Br?nsted산강도월고，π-흡부배합물월용역형성，최저흡부온도월저（CeY＜LaY＜CaY)。220℃하천투흡부용량수CaY＜LaY＜CeY증가，귀인우교소적강Br?nsted산화약Lewis산수량유리우HCFC-1122적π-흡부배합물인발정도교저적취합반응。흡부제적열탈부재생성능불가여기표면산중심복개물난이탈제유관。
Using CaCl2, La(NO3)3 and Ce(NO3) 3 solutions, NaY was ion-exchanged to prepare CaY, LaY and CeY zeolites. Adsorptive removal of trace amount of 1,1-difluoro-2-chloroethylene (HCFC-1122) from 1,1,1,2-tetrafluoroethane product over NaY, CaY, LaY, and CeY zeolites were investigated. The structure and surface properties of fresh and regenerated adsorbents were characterized by X-ray diffraction, pyridine infrared spectra techniques and temperature programmed desorption of ammonia. Results show that the residual ratio of HCFC-1122 impurity in the eluate can be decreased to 1.0% over CaY,LaY and CeY zeolitesvia the formation ofπ-adsorption complexes between HCFC-1122 and Br?nsted acid sites. The increase of intensity of Br?nsted acid favors the formation ofπ-adsorption complexes, consequently decreasing adsorption temperature for complete removal of HCFC-1122 (CeY < LaY < CaY). Breakthrough adsorption capacity of HCFC-1122 at 220℃ increases in the order of CaY < LaY < CeY, since lower density of strong Br?nsted and weak Lewis acid sites are favorable to lower degree polymerization initiated byπ-adsorption complexes. The thermal regeneration of adsorbents is unsatisfactory, attributed to hardly removal of contaminant on the acid sites of saturated adsorbents during the thermal regeneration process.
