Proses Produksi Biodiesel Berbasis Biji Karet

Abstract

Biodiesel tersusun dari berbagai macam ester asam lemak yang berasal dari minyak nabati. Lebih dari 30 macam tumbuhan Indonesia potensial menghasilkan minyak nabati. Salah satu minyak nabati diperoleh dari biji karet. Karenanya, pemanfaatan biji karet (Hevea Brasiliensis), sebagai sumber bahan baku biodiesel merupakan terobosan yang tepat untuk meningkatkan nilai tambah perkebunan karet. Penelitian ini dimaksudkan untuk menentukan pola pemungutan minyak biji karet secara maksimal dan mendapatkan kondisi proses produksi biodiesel yang memenuhi standar SNI dan ASTM. Proses produksi biodiesel dilakukan menggunakan prototip alat berkapasitas 20 liter/jam. Proses esterifikasi dijalankan pada suhu 105C, penambahan methanol 10% dan katalis asam, waktu 90 menit. Proses trans-esterifikasi dijalankan dalam reaktor alir osilasi dengan dosis katalis 1% berat minyak dan methanol sebanyak 15% berat minyak. Variabel yang dipelajari adalah suhu dan waktu proses. Produk biodiesel dimurnikan dengan sistem vakum. Dari hasil penelitian ini diperoleh rendemen kernel sebanyak 53% dari berat biji karet. Sedangkan minyak dalam kernel yang dapat dipungut maksimum 56% dari berat kernel. Karakteristik biodiesel sesuai dengan yang distandarisasikan, yaitu densitas 0,8565 g/ml, angka asam 0,49, angka iod 62,88, kadar ester 97,2%, flash point 178°C dan panas pembakaran 16183 J/g.

Kata Kunci: Biodiesel, minyak biji karet, reaktor osilasi, transesterifikasi

Biodiesel consists of various fatty acid esters which come from vegetable oil. More than 30 types of plants in Indonesia are potential to produce vegetable oils. One of the vegetable oils came from rubber seed. Therefore, utilization of rubber seed (Hevea Brasiliensis), as raw material for biodiesel was the precise breakthrough to add value to rubber plantation. This research aimed to determine the pattern of collection of oil of rubber seed maximally and to obtain the condition of production process of biodiesel fulfilling standard of SNI and ASTM. Biodiesel production was done in the prototype with a capacity of 20 liter/hour. The esterification process was conducted at 105°C using 10% methanol and acid catalyst for 90 minutes. Trans-esterification process was performed in an oscillating flow reactor with a catalyst dose of 1% oil weight and methanol as much as 15% oil weight. The effect of temperature and reaction time on product yield and quality were investigated. Purification of biodiesel was done in a vacuum system. Results from the present study showed that the yield of kernel through the process was up to 53% of the rubber seed weight. Meanwhile, the amount of oil could be extracted from the kernel was up to 56% of the kernel weight. The characteristic of biodiesel resulted from the process was in accord with that of the standard oil; density of 0.8565 g/ml, acid value 0.49, iodine value 62.88, ester fraction 97.2%, flash point 178C, heat of combustion 16,183 J/g.

Keywords: Biodiesel, rubber seed oil, oscillating reactor, transesterification