Aktivitas katalis NiMo/Zeolit dan NiMo/Zeolit-Nb2O5 untuk reaksi hidrorengkah sampah plastik polipropilena menjadi fraksi bensin
RODIANSONO, Dra. Wega Trisunaryanti, MS.,Ph.D.Eng
2005 | Tesis | S2 Ilmu KimiaTelah dilakukan penelitian aktivitas katalis NiMo/zeolit dan NiMo/zeolit- Nb2O5 untuk hidrorengkah fraksi sampah plastik jenis polipropilena (PP) menjadi fraksi bensin (hidrokarbon C5-C12). Penelitian ini dibagi tiga bagian yaitu: (1) optimasi proses hidrorengkah katalis NiMo/zeolit dengan variasi temperatur dan rasio katalis/umpan, (2) uji aktivitas katalis yang berbeda pada kondisi optimum dan (3) uji deaktivasi dan regenerasi katalis NiMo/zeolit. Katalis dibuat dengan metode impregnasi, dilanjutkan kalsinasi pada temperatur 500oC, oksidasi dan reduksi pada temperatur 400oC, masing-masing dengan aliran gas nitrogen, oksigen dan hidrogen. Karakterisasi katalis meliputi penentuan luas permukaan spesifk, rerata jejari pori dan volume total pori menggunakan metode BET, penentuan jumlah situs asam total menggunakan metode gravimetri dan kekuatan situs asam menggunakan sepektroskopi IR. Proses hidrorengkah dilakukan dalam reaktor semi alir (semi flow-fixed bed reactor) pada temperatur 300, 360, dan 400oC; rasio katalis/umpan 0,17; 0,25; 0,5 dengan laju alir gas hidrogen 150 mL/jam. Umpan diuapkan dalam reaktor pirolisis yang kemudian dialirkan ke reaktor hidrorengkah. Cairan hasil hidrorengkah ditampung dan dianalisis dengan kromatografi gas (GC) dan kromatografi gas-spektrometer massa (GC-MS) Hasil karakterisasi menunjukkan bahwa secara umum luas permukaan spesifik, rerata jejari pori dan volume total pori turun setelah pengembanan logam dan niobium oksida ke dalam zeolit. Jumlah situs asam total padatan setelah pengembanan logam meningkat dibandingkan sampel zeolit. Uji aktivitas katalis NiMo/zeolite yang menghasilkan selektivitas produk C7-C8 tertinggi (66,00%) dicapai pada temperatur 360oC dan rasio katalis/umpan 0,5. Aktivitas katalis pada kondisi optimum dari tinggi ke rendah: Ni/zeolit>NiMo/zeolit>NiMo/zeolit-Nb2O5 >Zeolit>Ni/Zeolit-Nb2O5 (konversi hidrokarbon C>12); NiMo/zeolit>Ni/zeolit >Ni/zeolit-Nb2O5>NiMo/zeolit-Nb2O5>Zeolit (total hasil fraksi bensin). Selektivitas produk C7-C8 katalis dari tinggi ke rendah: NiMo/zeolit- Nb2O5>Zeolit>Ni/zeolit>Ni/zeolit-Nb2O5>NiMo/zeolit. Penambahan niobium oksida meningkatkan secara signifikan selektivitas produk C7-C8. Kinerja katalis NiMo/zeolit menurun setelah pemakaian beberapa kali. Hasil regenerasinya menghasilkan katalis dengan aktivitas dan selektivitas yang hampir sama dengan katalis baru (fresh).
The activity of NiMo/zeolite and NiMo/zeolite-Nb2O5 catalysts for hydrocracking of waste plastic fraction polypropylene (PP) type was investigated. The present research was divided into three sections: (1) a study of the effect of temperature reaction and catalyst:feed ratio to the activity of NiMo/zeolite catalyst and (2) a study of the effect of catalyst types on hydrocracking of waste plastic fraction at the optimum condition, and (3) activity test and regeneration of NiMo/zeolite catalyst. Catalysts were prepared by impregnation method, then were calcined at 500oC, oxidized and reduced at 400oC under nitrogen, oxygen and hydrogen stream, respectively. The characterization of catalysts including spesific surface area, average pore radius, and total pore volume were determined by gas sorption analyzer, amount of total acid sites was determined by gas sorption method, and acid site strength was confirmed by IR spectroscopy. The hydrocracking process was carried out in a semi-flow reactor system at 300, 360, and 400oC and catalyst:feed ratio 0.17, 0.25, 0.5 under hydrogen stream (150 mL/hour). The feed was vaporized from the pyrolisis reactor into the hydrocracking reactor. A liquid product was collected and analyzed by gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The characterization results showed that spesific surface area, average pore radius, and total pore volume of the zeolite sample decreased after loading of the metal and Nb2O5. Amount of total acid sites of the catalysts were higher than that of the zeolite sample. The activity test of NiMo/zeolite catalyst which produced the optimum selectivity of C7-C8 products (66.00%) was achieved at 360oC and catalyst:feed ratio 0.5. The activity of catalysts at the optimum condition followed the order of Ni/zeolite>NiMo/zeolite>NiMo/zeolite-Nb2O5>Zeolite>Ni/zeolite- Nb2O5 (conversion of hydrocarbon C>12) and NiMo/zeolite>Ni/zeolite >Ni/zeolite-Nb2O5>NiMo/zeolite-Nb2O5>Z (total yield gasoline fraction). The selectivity of catalysts for C7-C8 product followed the order of NiMo/zeolite- Nb2O5>Zeolite>Ni/zeolite>Ni/zeolite-Nb2O5>NiMo/zeolite. Loading of Nb2O5 significantly affected the selectivity of C7-C8 products. The performance of NiMo/zeolite catalyst decreased after continously runs. Its regeneration produced the catalyst with similar activity and selectivity to the fresh catalyst.
Kata Kunci : Katalis NiMo/Zeolit,Reaksi Hidrorengkah,Fraksi Bensin, activity, polypropylene, catalyst, gasoline fraction
