Kajian Pengaruh Konsentrasi Logam Dan Ultrasonikasi Dalam Sintesis Katalis Pd–Ni/C Pada Upgrading Minyak Ko-Pirolisis Fraksi Kerosin Melalui Deoksigenasi Menjadi Bio-Hidrokarbon

Melisa Uvictoria, Dr. Sri Sudiono, M.Si;Dr. Nabila Aprianti, S.T

2026 | Skripsi | KIMIA

Minyak hasil ko-pirolisis masih memiliki kandungan senyawa teroksigenasi yang tinggi sehingga memerlukan proses catalytic hydrotreatmentdengan katalis bifungsional logam-asam untuk meningkatkan kualitasnya menjadi bio-hidrokarbon setara bahan bakar aviasi. Penelitian ini bertujuan untuk:(1)mengkaji pengaruh metode preparasi dengan ko-impregnasi basah dengan sekuensial bantuan gelombang ultrasonic; (2) mengevaluasi pengaruh metal loading terhadap distribusi logam, morfologi  permukaan,  dan  karakteristik  keasaman  katalis  Pd-Ni/C;  serta (3) menganalisis komposisi dan distribusi senyawa hidrokarbon dalam produk minyak ko-pirolisis yang dihasilkan melalui proses catalytic hydrotreatment dengan katalis Pd-Ni/C.

Katalis Pd-Ni/C dengan variasi metal loading 1%, 2%, dan 3% (rasio molar Pd:Ni = 1:1) dipreparasi melalui sequential wet impregnation pada penyangga karbon aktif, dengan satu varian metal loading 2% disintesis tambahan dengan bantuan gelombang ultrasonik (Pd-Ni/C 2%_US), diikuti kalsinasi pada 500 °C dengan gas N2 dan reduksi pada 350 °C dengan gas H2. Karakteristik katalis dianalisis menggunakan FTIR, XRD, SEM-EDS, dan NH3-TPD. Sementara itu, proses catalytic hydrotreatment dilakukan dengan perbadingaan katalis terhadap umpan adalah 1:20, pada suhu 250°C selama 4 jam dengan aliran gas H2 sebesar 25 bar. Minyak hasil catalytic hydrotreating dam dianalisis menggunakan GC-MS dan FTIR.

Hasil penelitian yang telah berhasil dilakukan menunjukan derajat kristalinitas meningkat seiring metal loading sementara itu ukuran kristalin rerata 14,55 nm (1%), 16,04 nm (2%), mengecil ke 12,15 nm (3%). Citra morfologi katalis dengan SEM menunjukan pada katalis 3% mengalami aglomerasi-agregasi paling signifikan dengan kristal baru berbentuk ulir dan pori tidak merata. Keasaman total (NH3-TPD) menngunakan metode sintesis dengan perbantuan gelombang ultrasonifikasi naik signifikan menjadi 2,4112 mmol/g pada katalis 2%_US. GC-MS produk hydrotreatment menujukan senyawa 2,4-dimetil-1-heptena (C9) dominan di seluruh variasi, dengan perubahan golongan olefine menjadi parrafinik dengan penurunan yield senyawa ini dan menyisakan 6,293?ngan katalis 1% .Distribusi atom karbon bergeser dari C8 (loading 1%) menuju C10 (loading 3%), sejalan menurunnya intensitas cracking akibat aglomerasi. Deoksigenasi paling efektif pada katalis 3%, dengan yield oksigenat tersisa terendah (alkohol (2,4,6-trimetilsikloheksil)metanol = 0,1995%), vs katalis 1% yang masih menyisakan fraksi asam karboksilat hingga ~17%. Ultrasonikasi dalam sintesis katalis pada 2% mendorong senyawa siklis-aromatik (etilbenzena dengan yield 2,183%) dan menekan overcracking (1-dekanol, 2-heksil- yield 1,870%).

Kata kunci: bio-hidrokarbon, catalytic hydrotreatment, katalis Pd-Ni/C, metal loading, ultrasonikasi, minyak ko-pirolisis

The oil produced by co-pyrolysis still contains high levels of oxygenated compounds, requiring a catalytic hydrotreatment process using a bifunctional metal-acid catalyst to improve its quality to that of aviation-grade biohydrocarbons. This study aims to: (1) investigate the effect of varying metal loadings (1%, 2%, and 3%) on the characteristics of the Pd-Ni/C catalyst prepared via ultrasonic-assisted wet impregnation; (2) evaluate the effect of metal loading on the metal distribution, surface morphology, and acidity characteristics of the Pd-Ni/C catalyst; and (3) analyze the composition and distribution of hydrocarbon compounds in the co-pyrolysis oil product resulting from catalytic hydrotreatment with the Pd-Ni/C catalyst.

Pd-Ni/C catalysts with metal loadings of 1%, 2%, and 3% (Pd:Ni molar ratio = 1:1) were prepared via sequential wet impregnation on an activated carbon support; one variant with a 2% metal loading was additionally synthesized using ultrasonic waves (Pd-Ni/C 2%_US), followed by calcination at 500 °C in N2 gas and reduction at 350 °C in H2 gas. The catalyst characteristics were analyzed using FTIR, XRD, SEM-EDS, and NH3-TPD. Meanwhile, the catalytic hydrotreatment process was carried out with a catalyst-to-feed ratio of 1:20, at 250 °C for 4 hours with a hydrogen gas flow of 25 bar. The oil resulting from the catalytic hydrotreatment was analyzed using GC-MS and FTIR.

The results of the successful study show that the degree of crystallinity increases with metal loading, while the average crystal size is 14.55 nm (1%), 16.04 nm (2%), and decreases to 12.15 nm (3%). SEM images of the catalyst morphology show that the 3% catalyst exhibits the most significant agglomeration and aggregation, with new spiral-shaped crystals and uneven pores. Total acidity (NH2-TPD) using the synthesis method aided by ultrasonication increased significantly to 2.4112 mmol/g in the 2%_US catalyst. GC-MS analysis of the hydrotreatment products showed that the 2,4-dimethyl-1-heptene (C9) compound was dominant across all variations; the shift from olefins to paraffins was accompanied by a decrease in the yield of this compound, leaving 6.293% with the 1% metal loading catalyst variance. The carbon atom distribution shifted from C8 (1% loading) to C10 (3% loading), in line with the decrease in cracking intensity due to agglomeration. Deoxygenation is most effective with the 3?talyst, yielding the lowest residual oxygenate content (2,4,6-trimethylcyclohexyl)methanol = 0.1995%), compared to the 1?talyst, which still leaves a carboxylic acid fraction of up to ~17%. Ultrasonication assisted on synthesis catalyst at 2% promotes cyclic-aromatic compounds (ethylbenzene with a yield 2.183%) and suppresses overcracking (1-decanol, 2-hexyl- yield 1.870%).

 

Keywords: biohydrocarbons, catalyst Pd-Ni/C,catalytic hydrotreatment, metal loading, ultrasonification

Kata Kunci : bio-hidrokarbon, catalytic hydrotreatment, katalis Pd-Ni/C, metal loading, ultrasonikasi