SKRIPSI
PERFORMANSI DIGESTER BIOGAS BERBAHAN BAKU
LIMBAH DAUN KAMBOJA DENGAN VARIASI SELANG
WAKTU PENGADUKAN SUBSTRAT
Oleh :
I MADE ARI DWINATHA
0819351022
FAKULTAS TEKNIK
JURUSAN TEKNIK MESIN PROGRAM NON REGULER
UNIVERSITAS UDAYANA
2015
PERNYATAAN
Dengan ini, saya nyatakan bahwa pada skripsi ini, tidak terdapat karya yang
pernah diajukan, untuk memperoleh gelar kesarjanaan di suatu perguruan tinggi, dan
sepanjang pengetahuan saya, juga tidak terdapat karya atau pendapat yang pernah
ditulis yang telah diterbitkan oleh orang lain, kecuali secara tertulis diacu dalam
naskah ini dan disebutkan dalam daftar pustaka.
Bukit Jimbaran, 15 Oktober 2015
I Made Ari Dwinatha
NIM : 0819351022
PERFORMANSI DIGESTER BIOGAS BERBAHAN BAKU LIMBAH DAUN
KAMBOJA DENGAN VARIASI SELANG WAKTU PENGADUKAN
SUBSTRAT
Oleh : I Made Ari Dwinatha
Dosen Pembimbing : Prof. I Nyoman Suprapta Winaya, ST., MASc, PhD.
: A. A. I. A. Sri Komaladewi, ST., MT.
ABSTRAKSI
Pada saat ini, pemanfaatan biogas yang berasal dari kotoran hewan, salah
satunya limbah kotoran sapi masih dalam batas skala kecil, dan pemanfaatan limbah
organik seperti limbah daun kamboja yang masih belum optimal dikembangkan
khususnya di daerah Bali. Pada penelitian ini akan ditunjukkan mengenai
performansi digester biogas berbahan baku limbah daun kamboja dengan variasi
selang waktu pengadukan substrat, yang memanfaatkan limbah kotoran sapi dan
daun kamboja sebagai bahan baku penghasil biogas.
Bahan baku limbah daun kamboja sebelumnya akan mendapat perlakuan
awal, untuk mengetahui total solid dan volatil solid dari bahan baku tersebut.
Terdapat 4 pengaturan variasi selang waktu pengadukan substrat pada tiap digester,
yaitu : pengaturan pengadukan selang waktu 3 jam untuk digester I, pengaturan
pengadukan selang waktu 4 jam, untuk digester II, pengaturan pengadukan selang
waktu 6 jam, untuk digester III dan tanpa melakukan pengadukan, untuk digester IV.
Penelititian ini dilakukan selama 30 hari dengan mencatat parameter tekanan dari
masing-masing digester.
Hasil penelitian yang paling baik ditunjukkan pada pengaturan pengadukan
dengan selang waktu 3 jam, 8 kali pengadukan selama 1 menit/hari pada digester I
dengan volume spesifik akumulasi sebesar 0,131 L/kgTS, dengan persentase kadar
CH4 sebesar 52,807 % dan CO2 sebesar 45,193%, dengan tekanan akumulasi sebesar
1,940 bar.
Kata Kunci : Biogas, Sistem Pengadukan, Daun kamboja, Total Solid.
THE PERFORMANCE OF THE BIOGAS DIGESTER MADE FROM
WASTE FRANGIFANI LEAF WITH AN INTERVAL OF VARIATION
STIRRING THE SUBSTRAT
By : I Made Ari Dwinatha
Supervisor : Prof. I Nyoman Suprapta Winaya, ST., MASc, PhD.
: A. A. I. A. Sri Komaladewi, ST., MT.
ABSTRACT
The current utilization of biogas derived which one from animal manure,
waste is still in limited small scale. And utilization of organic wastes such as
frangipani leaf waste that is still not optimal, especially developed areas of Bali. This
research demonstrated the performance of the biogas digester made from waste
frangipani leaf with an interval of variation stirring substrate utilizing cow manure
waste, and frangipani leaf as raw material for making biogas.
Frangipani leaf raw material waste will be treated before beginning to know
the total solid and volatile solid of the raw material, there are 4 performance digester
biogas made from waste frangipani leaf with a variation interval of stirring the
substrate, which utilizes waste and cow manure frangipani leaf as raw material
producers biogas, 4 setting variation interval of stirring substrates each digester is
stirring arrangement interval of 3 hours for the digester I, stirring arrangement
interval of 4 hours for the digester II, setting an interval of 6 hours stirring for
digester III and without stirring for digester IV. The research was conducted for 30
days to record pressure parameters of each digester.
The results of research is best shown in the stirring arrangement with an
interval of 3 hours, 8 times stirring for 1 minute at digester. The specific volume
accumulation of 0,131 L/kgTS, to the percentage levels of 52,807% CH4 and CO2 by
45,193%, with accumulation pressure of 1,940 bar.
Key Words : Biogas, Stirring System, Frangipani leaf, Total Solid.
KATA PENGANTAR
Puji syukur penulis panjatkan kepada Tuhan Yang Maha Esa, karena atas
berkat rahmat-Nya penulis dapat menyelesaikan skripsi yang berjudul :
“PERFORMANSI DIGESTER BIOGAS BERBAHAN BAKU LIMBAH DAUN
KAMBOJA DENGAN VARIASI SELANG WAKTU PENGADUKAN
SUBSTRAT”
Dalam penyusunan skripsi ini penulis tidak sedikit mendapat bantuan dari
berbagai pihak yang telah membimbing dengan sebaik-baiknya, untuk itu penulis
mengucapkan terima kasih yang sebesar-besarnya kepada :
1. Bapak Prof. I Nyoman Suprapta Winaya, ST., MASc., Ph.D, selaku Ketua
Jurusan Teknik Mesin, Fakultas Teknik, Universitas Udayana.
2. Bapak I Gusti Ngurah Putu Tenaya, ST, MT. selaku Dosen Pembimbing
Akademik.
3. Bapak Prof. I Nyoman Suprapta Winaya ST., MASc., Ph.D, selaku Dosen
Pembimbing I dalam penulisan skripsi ini.
4. Ibu A. A. I. A. Sri Komaladewi, ST, MT. selaku Dosen Pembimbing II
dalam penulisan skripsi ini.
5. Bapak/Ibu dosen serta staf pegawai Jurusan Teknik Mesin, Fakultas Teknik,
Universitas Udayana.
6. Rekan - rekan Jurusan Teknik Mesin, keluarga dan semua pihak yang telah
membantu dalam penyelesaian skripsi ini.
Penulis menyadari bahwa skripsi ini jauh dari kesempurnaan mengingat keterbatasan
pengetahuan dan referensi yang penulis miliki. Oleh karena itu kritik dan saran yang
bersifat membangun sangat penulis harapkan dari berbagai pihak. Sekali lagi penulis
mengucapkan banyak terima kasih dan penulis mohon maaf apabila terdapat
kekurangan atau kesalahan dalam penulisan skripsi ini.
Denpasar , Agustus 2015
Penulis
DAFTAR ISI
LEMBAR PENGESAHAN ............................................................................
i
LEMBAR PERNYATAAN ............................................................................
ii
ABSTRAK .......................................................................................................
iii
ABSTRACT .....................................................................................................
iv
KATA PENGANTAR .....................................................................................
v
DAFTAR ISI ...................................................................................................
vi
DAFTAR TABEL ...........................................................................................
x
DAFTAR GAMBAR .......................................................................................
xi
BAB I PENDAHULUAN ...............................................................................
.......................................................................................................................... 1
1.1 Latar Belakang ....................................................................................
............................................................................................................ 1
1.2 ................................................................................................. Ru
musan Masalah ...................................................................................
............................................................................................................ 3
1.3 ................................................................................................. Ba
tasan Masalah .....................................................................................
............................................................................................................ 3
1.4 ................................................................................................. Tu
juan Penelitian ....................................................................................
............................................................................................................ 3
Halaman
1.5 ................................................................................................. M
anfaat Penelitian .................................................................................
............................................................................................................ 3
BAB II LANDASAN TEORI ........................................................................
4
2.1 Sejarah Biogas .............................................................................
4
2.2 Pengertian Biogas ........................................................................
4
2.3 Proses Pembentukan Biogas ........................................................
5
2.4 Faktor-Faktor Pembentukan ........................................................
6
2.5 .................................................................................................. Ka
ndungan Biogas ...................................................................................
............................................................................................................. 8
2.6 .................................................................................................. Re
aktor Biogas .........................................................................................
8
2.7 .................................................................................................. Te
kanan Gas Biogas ................................................................................
11
2.8 .................................................................................................. In
okulum ................................................................................................
11
2.9 .................................................................................................. Je
nis-jenis Sampah .................................................................................
11
2.10 Karakteristik Limbah Daun kamboja ................................................
12
2.11 Volume Gas .......................................................................................
13
2.12 Total Solid(TS) ..................................................................................
13
2.13 Volatil Solid(VS) ...............................................................................
14
2.14 Volume Spesifik Biogas ....................................................................
14
2.14 Menghitung (CH4 dan CO2) ..............................................................
14
BAB III METODE PENELITIAN ................................................................
15
3.1 .................................................................................................. Te
mpat Penelitian ..................................................................................
15
3.2 .................................................................................................. Pe
ngambilan Sampel Awal ....................................................................
15
3.2.1 Perlakuan Awal Sampel ..........................................................
15
3.2.2 Pengujian Karakteristik ...........................................................
15
3.2.3 Pengujian Sampel Bahan Baku .................................................
15
3.3 .................................................................................................. Ra
ncangan Penelitian .............................................................................
18
3.3.1 ........................................................................................ Va
riabel Uji ................................................................................
19
3.3.1.1 ...........................................................................
Variabel bebas ............................................................
19
3.3.1.2 Variabel Terikat ........................................................
20
3.4 Alat Dan Bahan Penelitian ................................................................
23
3.4.1 Alat penelitian .........................................................................
23
3.4.2 Bahan Penelitian .....................................................................
26
3.5 Deskripsi Alat Penelitian ...................................................................
27
3.6 .................................................................................................. Pr
oses Penelitian .....................................................................................
28
3.6.1 ........................................................................................ Di
agram Alir Penelitian .............................................................
29
3.6.2 ........................................................................................ Pa
rameter Pengamatan ...............................................................
30
3.7 Metode Pencatatan Dan Pengolahan Data .........................................
30
3.7.1 Pencatatan Data ......................................................................
30
3.7.2 Pengolahan Data ....................................................................
30
BAB IV HASIL DAN PEMBAHASAN ........................................................
31
4.1 Data Awal Penelitian ..................................................................
31
4.1.1 ........................................................................................ Da
ta Sampel Kandungan Bahan Kering (TS) ............................
31
4.1.2 ........................................................................................ Da
ta Sampel Volatile Solids (VS) ..............................................
31
4.1.3 ........................................................................................ Da
ta Jumlah Bahan Baku Pervariasi Biogas ..............................
32
4.1.4 Data Hasil Penelitian ..............................................................
32
4.2 ..................................................................................................
Pengolahan Data ................................................................................
33
4.2.1 ........................................................................................ Te
kanan Akumulasi Biogas .......................................................
34
4.2.2 ........................................................................................ V
olume Akumulasi Biogas .......................................................
35
4.2.3 ........................................................................................ V
olume Spesifik Biogas ...........................................................
36
4.3 .................................................................................................. Pe
mbahasan ...........................................................................................
37
4.3.1 ........................................................................................ Te
kanan Akumulasi Biogas Harian ...........................................
37
4.3.2 ........................................................................................ V
olume Akumulasi Biogas Harian ...........................................
39
4.3.3 ........................................................................................ V
olume Spesifik Akumulasi Biogas Harian .............................
40
4.3.4 ........................................................................................ A
nalisa Kandungan Gas (CH4 dan CO2) ..................................
41
BAB VKESIMPULAN DAN SARAN ..........................................................
44
5.1 Kesimpulan ................................................................................
44
5.2 Saran ..........................................................................................
44
DAFTAR PUSTAKA ......................................................................................
45
LAMPIRAN ....................................................................................................
48
DAFTAR TABEL
Halaman
Tabel 2.1 Kandungan Biogas .........................................................................
8
Tabel 3.1 Rasio Campuran Pada Setiap Digester ..........................................
20
Tabel 3.2 Alat Penelitian ...............................................................................
23
Tabel 3.3 Bahan Penelitian ............................................................................
26
Tabel 4.1 Data Total Solid (TS) Dan Volatil Solid (VS)
Dari Sampel Daun kamboja ..........................................................
32
Tabel 4.2 Data Tekanan Biogas Harian .........................................................
33
Tabel 4.3 Data Tekanan Akumulasi Biogas Harian .......................................
34
Tabel 4.4 Data Hasil Volume Akumulasi Biogas Harian ..............................
36
Tabel 4.5 Data Hasil Volume Spesifik Akumulasi Biogas Harian ................
37
Tabel 4.6 Data Hasil Dan Pada Digester Biogas .............................
42
DAFTAR GAMBAR
Gambar 2.1 Skema Digester Biogas jenis Fixed Dome ................................
9
Gambar 2.2 Skema Digester Biogas jenis Floating Dome ...........................
10
Gambar 2.3 Pressure Gauge Digital .............................................................
11
Gambar 3.1 Alat Uji Analisa Ultimat ...........................................................
17
Gambar 3.2 Alat Uji Analisa Proksimat .......................................................
18
Gambar 3.3 Skematik Alat Pengaduk Dan Digester Biogas ........................
27
Gambar 3.4 Bagian-Bagian Alat Pengaduk Dan Digester Biogas ................
28
Gambar 3.5 Diagram Alir Penelitian ............................................................
29
Gambar 4.1 Grafik Tekanan Akumulasi Biogas Harian ...............................
38
Gambar 4.2 Grafik Volume Akumulasi Biogas Harian ................................
39
Halaman
Gambar 4.3 Grafik Volume Spesifik Akumulasi Biogas Harian .................
40
Gambar 4.4 Grafik Komposisi Kandungan Gas Pada Digester Biogas ........
43