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In this study, the performance of several differently treated natural zeolites in a sequential pyrolysis and catalytic reforming of plastic materials i.e. polypropylene (PP) and polystyrene (PS) were investigated. The experiments were carried out on two stage reactor using semi-batch system. The samples were degraded at 500°C in the pyrolysis reactor and then reformed at 450°C in the catalytic reformer. The results show that the mordenite-type natural zeolites could be used as efficient catalysts for the conversion of PP and PS into liquid and gaseous fuel. The treatment of natural zeolites in HCl solution showed an increase of the surface area and the Si/Al ratio while nickel impregnation increased the activity of catalyst. As a result, liquid product was reduced while gaseous product was increased. For PP, the fraction of gasoline (C5-C12) increased in the presence of catalysts. Natural zeolite catalysts could also be used to decrease the heavy oil fraction (>C20). The gaseous products were found that propene was dominated in all conditions. For PS, propane and propene were the main components of gases in the presence of nickel impregnated natural zeolite catalyst. Propene was dominated in pyrolysis over natural zeolite catalyst. The high quality of gaseous product can be used as a fuel either for driving gas engines or for dual-fuel diesel engine.

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This study aims to utilize pyrolysis oil produced from the pyrolysis of waste polyethylene in a direct injection (DI) diesel engine. In this paper, the performance and emission of a diesel engine have been studied using blends of waste polyethylene pyrolysis oil with diesel fuel under different loads condition. The waste polyethylene pyrolysis oil (WPO) used in this work was produced from the sequential pyrolysis and catalytic reforming of polyethylene bag after crushing and washing using natural zeolite (NZ) catalyst. Engine tests have been done using a four-cylinder and four-stroke diesel engine with the compression ratio of 22 and water cooling system. The experimental works were done at the rated engine speed of 1800 rpm. The results indicated that the brake thermal efficiencies are slightly higher as compared to that of diesel while the brake specific fuel consumption (BSFC) is slightly reduced when blending diesel fuel with WPO. Moreover, WPO-diesel fuel blends at various engine loads are also found to have influences on the emissions of CO, HC, NOx, and the smoke opacity. The NOx emission is found to be lowered by blending diesel with WPO. The decreased NOx emission is due to the decrease of the in-cylinder temperature by the effect of the non-homogeneity of WPO. The emissions of HC and CO of WPO-diesel blends are higher than that of diesel. Finally, the smoke opacity for WPO blends is slightly higher at higher loads.

AbstrakPermasalahan yang dihadapi pembuat dan pengguna briket adalah briket yang dihasilkan kualitasnya rendah ditinjau dari nilai kalor. Tujuan penelitian ini adalah menentukan kualitas briket terbaik dari limbah biomassa dalam memenuhi kebutuhan bahan bakar alternatif rumah tangga yang murah dan ramah lingkungan guna mewujudkan masyarakat mandiri energi. Metode yang digunakan untuk menentukan kualitas briket adalah metode Taguchi. Variabel bebas dalam penelitian ini adalah tekanan pengepressan, waktu penahanan, model cetakan, suhu pengeringan, lama pengeringan dan komposisi bahan, sedangkan variabel terikat adalah nilai kalor briket. Hasil penelitian menunjukkan bahwa kualitas briket terbaik ditinjau dari nilai kalor tertinggi yaitu pada setting parameter A2B1C2D2E2F1, artinya tekanan pengepressan 225 kg/cm 2 , waktu penahanan 5 menit, model cetakan sarang tawon (kotak), suhu pengeringan 60 C, lama pengeringan 3 hari, perbandingan limbah jarak pagar (Jatropha Curcas) : arang sekam : arang tempurung kelapa : perekat adalah 5 : 3: 2 : 1. Rata-rata nilai kalor biobriket yang dihasilkan sebesar 5.323 kal/g. Hal ini menunjukkan bahwa briket mempunyai nilai kalor yang tinggi dan memenuhi SNI, sehingga briket layak untuk memenuhi kebutuhan bahan bakar alternatif yang ramah lingkungan.Kata kunci: bahan bakar, briket, biomassa, energi alternatif, limbah padat, nilai kalor,ramah lingkungan. Abstract Problems that encountered on manufacturers and users of briquettes is low quality of the briquettes in terms of PENDAHULUANBerdasarkan data BPS Kab. Boyolali (Anonim, 2007), terdapat 40,48% warga Boyolali termasuk kategori keluarga miskin. Menurut Wardono (2010), budi daya tanaman jarak pagar di Desa Gondangrawe Kecamatan Andong seluas 75 ha, rata-rata menghasilkan biji jarak 487 ton/th biji jarak pagar dan limbah sebesar 300 ton/th berupa daun, batang, kulit biji jarak. Adapun lahan pertanian 108 ha menghasilkan padi 548 ton/th, limbah sekam padi sebesar 137 ton/th, limbah jerami basah sebesar 60 ton/ha dan jerami kering 40 ton/ha. Begitu pula dengan limbah tempurung kelapa di pasar tradisional yang melimpah. Limbah tersebut hanya sebagian kecil yang dimanfaatkan, sebagian besar hanya ditumpuk dan dibuang di sungai, sekitar tempat penggilingan, di areal persawahan atau dibakar. Hal ini mengakibatkan pencemaran lingkungan. Dalam kondisi seperti ini sangat dibutuhkan teknologi pengolahan limbah tersebut menjadi briket sebagai bahan bakar alternatif yang praktis, mudah, murah dan ramah lingkungan.Selanjutnya, dengan teknologi