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