Pengujian kualitas briket arang limbah serbuk gergaji dari Kabupaten Wonosobo

ROHMAN, Teguh Nur, Dr.Ing.Ir. Harwin Saptoadi, MSE

2007 | Tesis | S2 Teknik Mesin (Mag. Sistem Teknik-Tek. Peng

Wonosobo memiliki limbah kayu dalam jumlah yang besar yang tidak dimanfaatkan. Limabelas persen limbah kayu berbentuk serbuk gergaji. Untuk meminimalkan dampak lingkungan serbuk biasanya dibakar. Pada pembakaran bebas serbuk gergaji, energi yang dikandung tidak dapat dimanfaatkan. Serbuk gergaji dipirolisis menjadi arang. Pirolisis dilakukan pada dapur pirolisis yang telah dirancang sebelumnya. Sampel diambil dari tiga kecamatan, Kalikajar, Wonosobo and Sapuran di Kabupaten Wonosobo. Sampel serbuk gergaji dibakar tidak langsung dan dibakar bersamaan agar didapat perlakuan yang sama.. Kemudian dikempa dengan tekanan 159,091 kg/cm2, untuk memadatkan. Briket berbentuk silinder dengan diameter 20 mm and dibuat dari 100% arang, 75% arang dan 25% batubara, 50% arang dan 50% batubara. Briket ini dibuat dengan perbandingan arang : air : tapioka sebesar 35 : 7,212 : 0,288 Tujuan penelitian ini adalah untuk mengetahui kualitas briket arang limbah serbuk gergaji dari Kabupaten Wonosobo dibandingkan dengan SNI briket arang (SNI 01-6235-2000). Kualitas yang diuji adalah kadar air, kadar abu, kadar volatile matter, dan heating value. Kualitas sample serbuk gergaji dari Kalikajar adalah 12,5904%; 2,1054%; 45,9538%; 3899,5151 kal/g. Kualitas sample serbuk gergaji dari Wonosobo adalah 13,9617%; 3,1448%; 49,2957%; 3714,9553 kal/g. Kualitas sample serbuk gergaji dari Sapuran adalah 11,6997%; 3,3792%; 48,5677%; 3736,9887 kal/g. Kualitas sample briket arang dari Kalikajar adalah 5,2259%; 4,1025%; 31,4277%; 5348,5082 kal/g. Kualitas sample briket arang dari Wonosobo adalah 6,0114%; 6,3525%; 39,0780%; 4564,7161 kal/g. Kualitas sample briket arang dari Sapuran adalah 4,8979%; 4,2363%; 35,0838%; 5031,8820 kal/g. Kesimpulan yang dapat diambil dari penelitian ini adalah bahwa kualitas limbah serbuk gergaji memenuhi syarat SNI briket arang kecuali nilai volatile matter dan hanya satu sampel yang tidak memenuhi syarat SNI briket arang untuk heating value.

Wonosobo has a large amount of unutilized wood residues. Fifteen percent of wood residues are in form of saw dust. In order to minimize environmental pollution it is usually burned. Free burning of sawdust can not utilize its energy contents. In order to develop better fuel, saw dust is pyrolysed into char. The pyrolysis is carried out in a specially designed furnace. The samples are taken from three sub districts, i.e. Kalikajar, Wonosobo and Sapuran in the Wonosobo Regency. The sawdust samples are pyrolysed in an indirect burning condition. To obtain equal condition and treatment, the samples are pyrolysed together in the furnace. Then the char samples are densified with pressure of 159,091 kg/cm2 in a briquette machine. Briquettes are formed cylindrical with a diameter of 20 mm and composed from 100% percent sawdust char, 75% sawdust char added with 25% coal powder, and 50% sawdust char added with 50% coal powder. The briquettes are composed of char, water, and tapioca powder with mass ratio of 35, 7.212, and 0.288, respectively. The aim of this research is to investigate the quality of the charcoal briquettes made from Wonosobo regency sawdust compared to Indonesian National Standard (SNI 01-6235-2000). The quality parameters of the sawdust samples and coal powder are investigated before the pyrolysis process. After the briquetting process the quality parameters of the briquettes are investigated. The quality parameters are water content, ash content, volatile matter content, fixed carbon content and heating value. The quality parameters of the sawdust for sample from Kalikajar are 12.59%, 2.10%, 45.95%, 39.35%, and 3899.51 cal/g, while those from Wonosobo are 13.96%, 3.14%, 49.29%, and 3714.95 cal/g. The contents and heating value of samples from Sapuran are 11.69%, 3.37%, 48.56%, 48.56%, and 3736.98 cal/g. The quality parameters of the char sample from Kalikajar are 5.22%, 4.10%, 31.42%, 59.24%, and 5348.50 cal/g, while those from Wonosobo are 6.01%, 6.35%, 39.07%, 48,55%, and 4564.71 cal/g, and finally for sample from Sapuran are 4.89%, 4.23%, 35.08%, 55.78%, and 5031.88 cal/g. It can be concluded that the quality of the charcoal briquettes made from Wonosobo regency sawdust can comply with SNI values except their volatile matter contents and only one sample can not comply with SNI value in heating value.

Kata Kunci : briket, pirolisis, serbuk gergaji, briquettes, pyrolysis, sawdust