納米片型MFI分子篩超臨界催化裂解正十二烷和煤油對(duì)比研究
發(fā)布時(shí)間:2018-02-27 01:12
本文關(guān)鍵詞: 納米片型MFI分子篩 催化裂解 碳?xì)淙剂?低碳烯烴 熱沉 出處:《西安交通大學(xué)學(xué)報(bào)》2017年11期 論文類型:期刊論文
【摘要】:針對(duì)傳統(tǒng)ZSM-5分子篩孔徑小、反應(yīng)物分子擴(kuò)散路徑長(zhǎng)、催化活性穩(wěn)定性較差等問(wèn)題,通過(guò)水熱法合成了具有更高催化活性及穩(wěn)定性的納米片型MFI分子篩(Nanosheet MFI,NS-MFI),并通過(guò)XRD、BET、SEM、TEM和NH3-TPD表征,分別以正十二烷和煤油為超臨界催化裂解底物,測(cè)試了NS-MFI的催化活性及穩(wěn)定性,并與傳統(tǒng)的ZSM-5分子篩進(jìn)行比較。與ZSM-5分子篩相比,NS-MFI具有更高的比表面積、更大的孔容、更薄的片層結(jié)構(gòu)。在裂解正十二烷時(shí),NS-MFI催化裂解的產(chǎn)氣率更高,低碳烯烴的選擇性更高,產(chǎn)生的熱沉值更大。裂解煤油時(shí),在550℃時(shí),由于煤油中含有大量的環(huán)烷烴,使其更難被裂解,兩種分子篩催化裂解的活性相當(dāng);在600℃時(shí),NSMFI具有比ZSM-5更高的催化活性。兩種分子篩裂解煤油的活性均低于裂解正十二烷的活性,多級(jí)孔道結(jié)構(gòu)及較薄的片層結(jié)構(gòu)有利于反應(yīng)物及產(chǎn)物的擴(kuò)散,可提高催化劑的反應(yīng)活性及穩(wěn)定性。
[Abstract]:In view of the problems of small pore size, long molecular diffusion path of reactants and poor catalytic activity stability of traditional ZSM-5 molecular sieves, Nanosheet MFI molecular sieves with higher catalytic activity and stability were synthesized by hydrothermal method, and characterized by TEM and NH3-TPD. The catalytic activity and stability of NS-MFI were tested by using 12 alkane and kerosene as supercritical catalytic cracking substrates, and compared with traditional ZSM-5 molecular sieve. Compared with ZSM-5 molecular sieve, NS-MFI has higher specific surface area and larger pore volume. A thinner lamellar structure. When cracking 12 alkanes, the catalytic cracking of NS-MFI has higher gas yield, higher selectivity of low olefins and higher heat sink. When pyrolysis kerosene, at 550 鈩,
本文編號(hào):1540473
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