tugas akhir prarancangan pabrik asam nitrat …eprints.ums.ac.id/48051/8/halaman depan.pdf ·...
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Rizki Dyah Arimurti D500120045 i
TUGAS AKHIR
PRARANCANGAN PABRIK ASAM NITRAT
DARI ASAM SULFAT DAN NATRIUM NITRAT
KAPASITAS 35.000 TON PER TAHUN
HALAMAN JUDUL
Disusun sebagai salah satu syarat menyelesaikan Program Studi
Strata Satu Jurusan Teknik Kimia Fakultas Teknik
Oleh:
Rizki Dyah Arimurti
D 500 120 045
Dosen Pembimbing:
M. Mujiburohman, Ph.D.
Hamid Abdillah, S.T., M.T.
PROGRAM STUDI TEKNIK KIMIA FAKULTAS TEKNIK
UNIVERSITAS MUHAMMADIYAH SURAKARTA
SURAKARTA
2016
v
INTISARI
Pabrik asam nitrat dari natrium nitrat dan asam sulfat dengan kapasitas
35.000 ton/tahun direncanakan berdiri pada tahun 2020 di Karawang, Jawa Barat.
Bahan baku natrium nitrat diimpor dari Chili, dan asam sulfat dari PT Indonesian
Acid Industry. Proses pembuatan asam nitrat menggunakan Reaktor Alir Tangki
Berpengaduk (RATB). Reaksi pembentukan asam nitrat berlangsung pada kondisi
eksotermis, non adiabatis dengan pendingin berupa jaket, reaksi berjalan secara
irreversible, beroperasi pada suhu 150°C dan tekanan 1 atm. Pabrik ini tergolong
pabrik berisiko rendah karena kondisi operasi atmosferis.
Reaksi pembentukan asam nitrat diawali dengan mereaksikan asam sulfat
dan natrium nitrat dalam reaktor (R-110). Produk keluar dari reaktor berupa gas
diembunkan dalam kondensor kemudian dimurnikan di dalam menara distilasi
untuk menghasilkan produk dengan kemurnian 98%, sedangkan hasil bawah
reaktor berupa campuran asam nitrat, natrium nitrat, dan natrium bisulfat (niter
cake). Produk asam nitrat yang dihasilkan sebesar 4.419,1919 kg/jam. Unit
pendukung proses terdiri dari unit penyedia air pendingin sebesar 119.178,1218
kg/jam, kebutuhan steam sebesar 8.871,2408 kg/jam yang diperoleh dari boiler
dengan bahan bakar fuel oil sebesar 793,4961 L/jam, dan kebutuhan air sanitasi
sebesar 1.288,3656 kg/jam. Kebutuhan air diperoleh dari air sungai Kalimalang,
sedangkan kebutuhan listrik dipenuhi dari PLN dan generator set sebagai
cadangan apabila PLN mengalami gangguan.
Dari analisis ekonomi pabrik asam nitrat menunjukkan keuntungan sebelum
pajak sebesar Rp56.960.386.562 per tahun, keuntungan setelah pajak sebesar
Rp42.720.289.922. Percent return on investment (ROI) sebelum pajak 21,34%
dan setelah pajak 16,01%. Pay Out Time (POT) sebelum pajak 3,19 tahun dan
setelah pajak 3,85 tahun. Break Event Point (BEP) sebesar 57,60%, Shut Down
Point (SDP) sebesar 27,79%, dan Internal Rate of Return (IRR) sebesar 31,91%.
Dari data analisis kelayakan di atas disimpulkan bahwa pabrik ini layak untuk
didirikan.
Kata kunci: Asam nitrat, asam sulfat, niter cake, RATB
vi
ABSTRACT
Nitric acid plant with raw materials of sulphuric acid and sodium nitrate
with a capacity 35.000 tons/year is planned to be established in 2020 in
Karawang, West Java. The sodium nitrate is imported from Chile and the
sulphuric acid is from PT Indonesian Acid Industry. The nitric acid production
uses continuous stirred tank reactor (CSTR). The reaction is exothermic, non
adiabatic, and irreversible, carried out at temperature of 150°C and pressure of 1
atm. The plant is categorized as low risk process due to the friendly operating
conditions.
The process of nitric acid production is initiated with reacting sulphuric
acid and sodium nitrate in the reactor. The vapor product of reactor is condensed
by a partial condenser and is purified in distillation tower to produce nitric acid
with purity of 98%, while the liquid product, called niter cake, is stored as side
product. Based on the capacity, the production of nitric acid is 4,419.1919
kgs/hour. To support the process, utilities are required including 119,178.1218
kgs/hour of cooling water, 8,871.2408 kgs/hour of steam. Which is obtained from
boiler consuming fuel oil as much as 793.4961 L/hour, and electricity supplied
from PLN and generator set. The water source is taken from Kalimalang river,.
The economic analysis gives the profit before tax is
Rp56,960,386,562/year, and Rp42,720,289,922/year after tax. The percent Return
on Investment (ROI) before tax is 21.34% and 16.01% after tax. The Pay Out
Time (POT) before tax is 3.19 years and 3.85 years after tax. The Break Event
Point (BEP), the Shut Down Point (SDP), and the Internal Rate of Return (IRR)
are 57.60, 27.79%, and 31.91%, respectively. The above economic analysis
concludes that the plant is feasible to set.
Keyword: CSTR, niter cake, nitric acid, sulphuric acid
vii
KATA PENGANTAR
Syukur Alhamdulillah, segala puji bagi Allah SWT karena rahmat dan
hidayah-Nya, penulis akhirnya dapat menyelesaikan tugas prarancangan asam
nitrat dari asam sulfat dan natrium nitrat kapasitas 35.000 ton/tahun. Tugas
prarancangan pabrik kimia merupakan syarat kelulusan untuk mahasiswa S1
program studi teknik kimia Universitas Muhammadiyah Surakarta. Dengan
terselesainya tugas ini tidak terlepas dari bantuan banyak pihak yang telah
memberikan masukan – masukan kepada penulis. Untuk itu penulis mengucapkan
terima kasih kepada:
1. Orang tua dan keluarga yang selalu memberikan dukungan dan doa sehingga
tugas prarancangan pabrik kimia ini selesai.
2. Bapak Rois Fatoni, S.T., M.Sc., Ph.D., selaku ketua jurusan program studi
teknik kimia.
3. Bapak M. Mujiburohman, Ph.D., selaku dosen pembimbing I yang telah
memberikan dukungan, bimbingan, dan bantuannya untuk penyelesaian tugas
prarancangan pabrik ini.
4. Bapak Hamid Abdillah, S.T., M.T., selaku dosen pembimbing II yang telah
memberikan bimbingan dan dukungan.
5. Luluk Pratiwi partner sekaligus sahabat yang selalu mendukung, membantu,
dan memberi semangat dalam penyelesaian tugas ini.
6. Semua pihak yang telah membantu serta memberi semangat dalam
penyusunan tugas prarancangan pabrik kimia ini.
Penulis menyadari bahwa tugas prarancangan pabrik kimia ini belum
sempurna. Oleh karena itu, penulis mengharapkan kritik dan saran yang
membangun. Semoga tugas prarancangan pabrik kimia ini dapat memberikan
manfaat bagi kami pada khususnya dan pembaca pada umumnya.
Surakarta, November 2016
Penulis
viii
DAFTAR ISI
HALAMAN JUDUL ................................................................................................ i
HALAMAN PENGESAHAN ................................................................................. ii
PERNYATAAN KEASLIAN SKRIPSI ................................................................ iv
INTISARI ................................................................................................................ v
KATA PENGANTAR ........................................................................................... vii
DAFTAR ISI ........................................................................................................ viii
DAFTAR TABEL ................................................................................................. xii
DAFTAR GAMBAR ........................................................................................... xiv
BAB I PENDAHULUAN ................................................................................ 1
1.1 Latar Belakang Pendirian Pabrik ................................................ 1
1.2 Kapasitas Pabrik .......................................................................... 1
1.3 Pemilihan Lokasi Pabrik ............................................................. 2
1.4 Tinjauan Pustaka ......................................................................... 5
1.4.2 Kegunaan Produk.............................................................. 6
1.4.3 Sifat Fisik dan Kimia Bahan Baku dan Produk ................ 7
1.4.4 Tinjauan Proses Secara Umum ......................................... 9
BAB II DESKRIPSI PROSES ........................................................................ 10
2.1 Spesifikasi Bahan Baku dan Produk ......................................... 10
2.1.1 Spesifikasi Bahan Baku .................................................. 10
2.1.2 Spesifikasi Produk .......................................................... 10
2.2 Konsep Reaksi .......................................................................... 11
2.2.1 Dasar Reaksi ................................................................... 11
2.2.2 Kondisi Operasi .............................................................. 11
2.2.3 Tinjauan Termodinamika................................................ 11
2.2.4 Tinjauan Kinetika ........................................................... 13
2.3 Deskripsi Proses ........................................................................ 13
2.3.1 Diagram Alir Proses ....................................................... 15
2.4 Neraca Massa ............................................................................ 18
2.5 Neraca Panas ............................................................................. 20
ix
2.6 Tata Letak Peralatan ................................................................. 24
2.6.1 Tata Letak Pabrik ............................................................ 24
2.6.2 Tata Letak Proses ............................................................ 27
BAB III SPESIFIKASI ALAT PROSES ......................................................... 30
3.1 Reaktor ...................................................................................... 30
3.2 Separator ................................................................................... 30
3.3 Absorber .................................................................................... 31
3.4 Menara distilasi ......................................................................... 32
3.5 Tangki ....................................................................................... 33
3.5.1 Tangki-01 ........................................................................ 33
3.5.2 Tangki-02 ........................................................................ 33
3.5.3 Tangki-03 ........................................................................ 34
3.5.4 Tangki-04 ........................................................................ 35
3.6 Belt conveyor ............................................................................ 36
3.7 Bucket elevator .......................................................................... 37
3.8 Hopper ...................................................................................... 37
3.9 Blower ....................................................................................... 38
3.10 Heater ....................................................................................... 38
3.11 Condensor ................................................................................. 39
3.12 Cooler ....................................................................................... 41
3.12.1 Cooler-01 ........................................................................ 41
3.12.2 Cooler-02 ........................................................................ 41
3.12.3 Cooler-03 ........................................................................ 42
3.13 Reboiler ..................................................................................... 43
3.14 Accumulator .............................................................................. 43
3.15 Mixer ......................................................................................... 44
3.16 Pompa ....................................................................................... 45
3.16.1 Pompa-01 ....................................................................... 45
3.16.2 Pompa-02 ....................................................................... 45
3.16.3 Pompa-03 ....................................................................... 46
3.16.4 Pompa-04 ....................................................................... 46
x
3.16.5 Pompa-05 ..................................................................... 47
3.16.6 Pompa-06 ....................................................................... 47
3.16.7 Pompa-07 ....................................................................... 48
3.16.8 Pompa-08 ....................................................................... 48
3.16.9 Pompa-09 ....................................................................... 49
BAB IV UNIT PENDUKUNG PROSES DAN LABORATORIUM .............. 50
4.1 Unit Pendukung Proses ............................................................. 50
4.1.1 Unit Penyediaan dan Pengolahan Air ............................. 51
4.1.2 Unit Penyediaan Steam ................................................... 62
4.1.3 Unit Penyediaan Listrik .................................................. 63
4.1.4 Unit penyediaan bahan bakar.......................................... 66
4.1.5 Unit Pengolahan Limbah ................................................ 75
4.1.6 Unit Penyediaan Udara Tekan ........................................ 75
4.2 Laboratorium ............................................................................. 76
4.2.1 Laboratorium Fisik ......................................................... 77
4.2.2 Laboratorium Analitik .................................................... 77
4.2.3 Laboratorium Penelitian dan Pengembangan ................. 78
4.2.4 Analisis Air ..................................................................... 78
4.2.5 Analisis Sampel .............................................................. 78
BAB V MANAJEMEN PERUSAHAAN ....................................................... 79
5.1 Bentuk Perusahaan .................................................................... 79
5.2 Struktur Organisasi ................................................................... 80
5.3 Tugas dan Wewenang ............................................................... 83
5.4 Pembagian Jam Kerja Karyawan .............................................. 89
5.5 Kepegawaian dan Sistem Upah ................................................ 91
5.6 Sistem Gaji Karyawan .............................................................. 92
5.7 Kesejahteraan Sosial Karyawan ................................................ 93
5.8 Kesehatan dan Keselamatan Kerja ............................................ 94
5.9 Manajemen Produksi ................................................................ 95
5.9.1 Perencanaan Produksi ..................................................... 95
5.9.2 Pengendalian Produksi.................................................... 96
xi
BAB VI ANALISIS EKONOMI ...................................................................... 98
6.1 Dasar Perhitungan ..................................................................... 99
6.2 Perkiraan Harga Alat ................................................................. 99
6.3 Perhitungan Biaya ................................................................... 101
6.3.1 Investasi Modal (Capital Investment) ........................... 101
6.3.2 Biaya Produksi (Manufacturing Cost) .......................... 101
6.3.3 Pengeluaran Umum (General Expense) ....................... 102
6.4 Analisis Kelayakan ................................................................. 102
6.5 Hasil Perhitungan .................................................................... 103
6.6 Analisis Kelayakan ................................................................. 106
6.7 Kesimpulan ............................................................................. 112
DAFTAR PUSTAKA ......................................................................................... 113
LAMPIRAN ........................................................................................................ 115
xii
DAFTAR TABEL
Tabel 1.1 Data impor perdagangan asam nitrat ...................................................... 2
Tabel 1.2 Kapasitas produksi pabrik asam nitrat di dunia ...................................... 2
Tabel 2.1 Harga ΔH°F298 dan ΔG°F298 ................................................................... 12
Tabel 2.2 Neraca massa di reaktor ........................................................................ 18
Tabel 2.3 Neraca massa di kondensor ................................................................... 18
Tabel 2.4 Neraca massa di separator ..................................................................... 19
Tabel 2.5 Neraca massa di absorber ...................................................................... 19
Tabel 2.6 Neraca massa di mixer .......................................................................... 19
Tabel 2.7 Neraca massa di menara distilasi .......................................................... 20
Tabel 2.8 Neraca massa overall pabrik asam nitrat .............................................. 20
Tabel 2.9 Data heat capacity of gas masing-masing komponen ........................... 20
Tabel 2.10 Neraca panas di heater ........................................................................ 21
Tabel 2.11 Neraca panas di reaktor ....................................................................... 21
Tabel 2.12 Neraca panas di kondensor ................................................................. 22
Tabel 2.13 Neraca panas di separator ................................................................... 22
Tabel 2.14 Neraca panas di cooler (E-130) .......................................................... 23
Tabel 2.15 Neraca panas di cooler (E-131) .......................................................... 23
Tabel 2.16 Neraca panas di absorber .................................................................... 23
Tabel 2.17 Neraca panas di menara distilasi ......................................................... 24
Tabel 2.18 Perincian luas tanah bangunan pabrik ................................................ 26
Tabel 4.1 Daftar kebutuhan air pendingin............................................................. 61
Tabel 4.2 Daftar kebutuhan air untuk steam ......................................................... 61
Tabel 4.3 Daftar kebutuhan air sanitasi................................................................. 62
Tabel 4.4 kebutuhan listrik proses ........................................................................ 64
Tabel 4.5 Kebutuhan listrik utilitas ....................................................................... 65
Tabel 4.6 Total kebutuhan listrik .......................................................................... 66
Tabel 5.1 Karyawan proses ................................................................................... 89
Tabel 5.2 Jadwal kerja Kelompok Shift ................................................................ 91
Tabel 5.3 Sistem gaji karyawan ............................................................................ 92
xiii
Tabel 6.1 Cost index chemical plant ..................................................................... 99
Tabel 6.2 Total fixed capital investment ............................................................. 103
Tabel 6.3 Total working capital .......................................................................... 104
Tabel 6.4 Total capital investment ...................................................................... 104
Tabel 6.5 Direct manufacturing cost .................................................................. 104
Tabel 6.6 Indirect Manufacturing cost................................................................ 105
Tabel 6.7 Fixed manufacturing cost ................................................................... 105
Tabel 6.8 Total manufacturing cost .................................................................... 105
Tabel 6.9 General expense .................................................................................. 105
Tabel 6.10 Total production cost ........................................................................ 106
Tabel 6.11 Fixed cost .......................................................................................... 108
Tabel 6.12 Variable cost ..................................................................................... 108
Tabel 6.13 Regulated cost ................................................................................... 108
Tabel 6.14 Analisis kelayakan ............................................................................ 110
xiv
DAFTAR GAMBAR
Gambar 2.1 Diagram alir kualitatif pabrik asam nitrat dari asam sulfat dan
natrium nitratrat kapasitas 35.000 ton/tahun ................................ 16
Gambar 2.2 Diagram alir kuantitatif pabrik asam nitrat dari asam sulfat dan
natrium nitratrat kapasitas 35.000 ton/tahun ................................ 17
Gambar 2.3 Tata letak pabrik asam nitrat dari asam sulfat dan natrium
nitrat ................................................................................................ 27
Gambar 2.4 Tata letak peralatan proses pada pabrik asam nitrat dari asam
sulfat dan natrium nitrat.................................................................. 29
Gambar 4.1 Denah utilitas pada pabrik asam nitrat dari asam sulfat dan
natrium nitrat .................................................................................. 55
Gambar 5.1 Struktur organisasi perusahaan ....................................................... 82
Gambar 6.1 Hubungan tahun dan index cost pada pabrik asam nitrat ............. 100