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TUGAS AKHIR
PRARANCANGAN PABRIK ASAM NITRAT
DARI ASAM SULFAT DAN NATRIUM NITRAT
KAPASITAS 65.000 TON PER TAHUN
HALAMAN JUDUL
Diajukan Guna Melengkapi Persyaratan dalam Menyelesaikan Pendidikan
Tingkat Strata Satu di Jurusan Teknik Kimia Fakultas Teknik
Universitas Muhammadiyah Surakarta
Oleh:
Luluk Pratiwi
D 500 120 070
Dosen Pembimbing:
M. Mujiburohman, Ph.D.
Hamid Abdillah, S.T., M.T.
PROGRAM STUDI TEKNIK KIMIA FAKULTAS TEKNIK
UNIVERSITAS MUHAMMADIYAH SURAKARTA
SURAKARTA
2016
v
KATA PENGANTAR
Puji syukurkepada Allah SWT, karena atas rahmat dan karunia-Nya
penulis akhirnya dapat menyelesaikantugas prarancangan pabrik asam nitrat dari
asam sulfat dan natrium nitrat kapasitas 65.000 ton/tahun.
Laporan ini dibuat untuk memenuhi mata kuliah tugas prarancangan
pabrik. Tugas prarancangan pabrik merupakan syarat kelulusan bagi mahasiswa
tahap sarjana di Jurusan Teknik Kimia, Fakultas Teknik, Universitas
Muhammadiyah Surakarta. Dalam penyusunan laporan ini penulis banyak
mendapat bimbingan, dorongan dan motivasi dari berbagai pihak. Untuk itu, kami
ingin mengucapkan terima kasih kepada:
1. Orang tua dan keluarga yang selalu memberikan dukungan dan doa sehingga
tugas prarancangan pabrik ini selesai.
2. Bapak Rois Fatoni, S.T., M.Sc., Ph.D., selaku Ketua Jurusan Teknik Kimia
FT-UMS.
3. Bapak M. Mujiburohman Ph.D., selaku pembimbing I atas bimbingan,
bantuan dan perhatiannya.
4. Bapak Hamid Abdillah, S.T., M.T., selaku dosen pembimbing II atas
bimbingan, bantuan dan perhatiannya.
5. Rizki Dyah Arimurti partner tugas prarancangan pabrik yang telah membantu
dan mendukung dalam segala hal.
6. Fernanto, Andayani, Hendra, Ifur, Edo sebagai partnerdan sahabat-sahabat
yang luar biasa.
7. Semua pihak yang membantu dalam penyusunan tugas prarancangan pabrik
ini.
Penulis menyadari bahwa tugas prarancangan pabrik ini masih ada
kekurangan, karena itu kami mengharapkan segala kritik dan saran yang
membangun. Semoga tugas prarancangan pabrik yang kami laksanakan ini dapat
bermanfaat khususnya di bidang teknik kimia dan aplikasi di industri kimia.
Surakarta, Oktober 2016
Penulis
vi
DAFTAR ISI
HALAMAN JUDUL ................................................................................................ i
HALAMAN PENGESAHAN ................................................................................ iii
PERNYATAAN KEASLIAN SKRIPSI ................................................................ iv
KATA PENGANTAR ............................................................................................. v
DAFTAR ISI .......................................................................................................... vi
DAFTAR TABEL .................................................................................................. xi
DAFTAR GAMBAR ........................................................................................... xiii
INTISARI ............................................................................................................. 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
1.4.1 Pemilihan Proses .................................................................... 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
2.4 Neraca Massa .................................................................................. 15
2.5 Neraca Panas ................................................................................... 17
vii
b. Diagram Alir Proses dan Material ................................................... 22
2.7 Tata Letak Peralatan ........................................................................ 24
2.7.1 Tata Letak Pabrik .................................................................. 24
2.7.2 Tata Letak Proses .................................................................. 28
BAB III SPESIFIKASI ALAT PROSES .............................................................. 31
3.1 Reaktor ............................................................................................ 31
3.2 Separator.......................................................................................... 31
3.3 Absorber .......................................................................................... 32
3.4 Menara Distilasi .............................................................................. 33
3.5 Tangki.............................................................................................. 34
3.5.1 Tangki-110 ............................................................................ 34
3.5.2 Tangki-111 ............................................................................ 35
3.5.3 Tangki-112 ............................................................................ 36
3.5.4 Tangki-113 ............................................................................ 37
3.6 Belt Conveyor .................................................................................. 38
3.7 Bucket Elevator ............................................................................... 38
3.8 Hopper ............................................................................................. 39
3.9 Blower ............................................................................................. 39
3.10 Heater .............................................................................................. 40
3.10.1 Heater-110 .......................................................................... 40
3.10.2 Heater-111 .......................................................................... 40
3.11 Condensor ....................................................................................... 41
3.11.1 Condensor-120 .................................................................... 41
3.11.2 Condensor-121 .................................................................... 42
3.12 Cooler .............................................................................................. 42
3.12.1 Cooler-130 .......................................................................... 42
3.12.2 Cooler-131 .......................................................................... 43
3.12.3 Cooler-132 .......................................................................... 44
3.13 Reboiler ........................................................................................... 44
3.14 Accumulator .................................................................................... 45
3.15 Mixer ............................................................................................... 46
viii
3.16 Pompa .............................................................................................. 46
3.16.1 Pompa-110 .......................................................................... 46
3.16.2 Pompa-111 .......................................................................... 47
3.16.3 Pompa-112 .......................................................................... 48
3.16.4 Pompa-113 .......................................................................... 48
3.16.5 Pompa-114 .......................................................................... 49
3.16.6 Pompa-115 .......................................................................... 50
3.16.7 Pompa-116 .......................................................................... 50
3.16.8 Pompa-117 .......................................................................... 51
3.16.9 Pompa-118 .......................................................................... 52
BAB IV UNIT PENDUKUNG PROSES (UTILITAS) DAN
LABORATORIUM ................................................................................. 53
4.1 Unit Pendukung Proses (Utilitas) .................................................... 53
4.1.1 Unit Pendukung Proses (Utilitas) .......................................... 54
4.1.2 Unit Penyediaan Steam ......................................................... 65
4.1.3 Unit Penyediaan Listrik ........................................................ 65
4.1.4 Unit Penyediaan Bahan Bakar .............................................. 68
4.1.5 Spesifikasi Alat Utilitas ........................................................ 69
4.1.6 Unit Pengolahan Limbah ...................................................... 77
4.1.7 Unit Penyediaan Udara Tekan .............................................. 78
4.2 Laboratorium ................................................................................... 79
4.2.1 Laboratorium Fisik ................................................................ 80
4.2.2 Laboratorium Analitik .......................................................... 80
4.2.3 Laboratorium Penelitian dan Pengembangan ....................... 80
4.2.4 Analisis Air ........................................................................... 80
4.2.5 Analisis Sampel .................................................................... 81
BAB V MANAJEMEN PERUSAHAAN ............................................................ 82
5.1 Bentuk Perusahaan .......................................................................... 82
5.2 Struktur Organisasi .......................................................................... 83
5.3 Tugas dan Wewenang ..................................................................... 86
5.3.1 Pemegang Saham .................................................................. 86
ix
5.3.2 Direktur Utama ..................................................................... 86
5.3.3 Staff Ahli ............................................................................... 87
5.3.4 Kepala Bagian ....................................................................... 87
5.3.5 Kepala Seksi .......................................................................... 90
5.4 Pembagian Jam Kerja Karyawan .................................................... 90
5.4.1 Karyawan Non Shift .............................................................. 90
5.4.2 Karyawan Shift ...................................................................... 91
5.5 Kepegawaian dan Sistem Upah ....................................................... 92
5.6 Penggolongan Jabatan, Jumlah Karyawan, dan Gaji ...................... 93
5.6.1 Penggolongan Jabatan ........................................................... 93
5.6.2 Jumlah Karyawan dan Gaji ................................................... 93
5.7 Kesejahteraan Sosial Karyawan ...................................................... 94
5.8 Kesehatan dan Keselamatan Kerja .................................................. 95
5.9 Manajemen Produksi ....................................................................... 95
5.9.1 Perencanaan Produksi ........................................................... 96
5.9.2 Pengendalian produksi .......................................................... 97
BAB VI ANALISIS EKONOMI ........................................................................... 98
6.1 Dasar Perhitungan ........................................................................... 98
6.2 Perhitungan Biaya ......................................................................... 101
6.2.1 Investasi Modal (Capital Invesment) .................................. 101
6.2.2 Biaya Produksi (Manufacturing Cost) ................................ 101
6.2.3 Pengeluaran Umum (General Expenses) ............................ 101
6.3 Analisis Kelayakan ........................................................................ 102
6.3.1 Percent Return On Investment (ROI) .................................. 102
6.3.2 Pay Out Time (POT) ........................................................... 102
6.3.3 Break Event Point (BEP) .................................................... 103
6.3.4 Shut Down Point (SDP) ...................................................... 103
6.3.5 Internal Rate Of Return (IRR) ............................................. 103
6.4 Hasil Perhitungan .......................................................................... 104
6.4.1 Total Fixed Capital Investment ........................................... 104
6.4.2 Working Capital .................................................................. 104
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6.4.3 Total Capital Investment ..................................................... 104
6.4.4 Direct Manufacturing Cost ................................................. 105
6.4.5 Indirect Manufacturing Cost ............................................... 105
6.4.6 Fixed Manufacturing Cost .................................................. 105
6.4.7 Total Manufacturing Cost ................................................... 106
6.4.8 General Expense ................................................................. 106
6.4.9 Total Production Cost ......................................................... 106
6.4.10 Perhitungan Keuntungan Produksi .................................... 106
6.5 Analisis Kelayakan ........................................................................ 107
6.6 Kesimpulan.................................................................................... 112
DAFTAR PUSTAKA .......................................................................................... 113
LAMPIRAN ......................................................................................................... 115
xi
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 ∆Ho
F298dan∆Go
F298 ..................................................................... 12
Tabel 2.2 Neraca massa di reaktor ........................................................................ 15
Tabel 2.3 Neraca massa di kondensor ................................................................... 16
Tabel 2.4 Neraca massa di separator ..................................................................... 16
Tabel 2.5 Neraca massa di absorber ...................................................................... 16
Tabel 2.6 Neraca massa di mixer .......................................................................... 16
Tabel 2.7 Neraca massa di menara distilasi .......................................................... 17
Tabel 2.8 Neraca massa overall pabrik asam nitrat asam sulfat dan natrium
nitrat ...................................................................................................... 17
Tabel 2.9 Data heat capacity of gas masing-masing komponen ........................... 17
Tabel 2.10 Data heat capacity of liquid masing-masing komponen ..................... 18
Tabel 2.11 Neraca panas di heater ........................................................................ 18
Tabel 2.12 Neraca panas di reaktor ....................................................................... 19
Tabel 2.13 Neraca panas di kondensor ................................................................. 19
Tabel 2.14 Neraca panas di separator ................................................................... 19
Tabel 2.15 Neraca panas di cooler ........................................................................ 20
Tabel 2.16 Neraca panas di cooler ........................................................................ 20
Tabel 2.17 Neraca panas di absorber .................................................................... 20
Tabel 2.18 Neraca panas di menara distilasi ......................................................... 21
Tabel 2.19 Luas bangunan pabrik ......................................................................... 26
Tabel 4.1 Daftar kebutuhan air pendingin............................................................. 64
Tabel 4.2 Daftar kebutuhan air steam ................................................................... 64
Tabel 4.5 Kebutuhan listrik proses........................................................................ 66
Tabel 4.6 Kebutuhan listrik utilitas ....................................................................... 67
Tabel 4.7 Kebutuhan listrik total ............................................................................ 68
Tabel 5.1 Jadwal kerja kelompok shift ................................................................... 94
Tabel 5.2 Penggolongan jabatan, jumlah karyawan dan gaji ................................ 93
xii
Tabel 6.1 Cost index chemical plant ..................................................................... 99
Tabel 6.2 Total fixed capital investment ............................................................. 104
Tabel 6.3 Total working capital .......................................................................... 104
Tabel 6.4 Total capital investment ...................................................................... 104
Tabel 6.5 Total direct manufacturing cost .......................................................... 105
Tabel 6.6 Total indirect manufacturing cost ....................................................... 105
Tabel 6.7 Total fixed manufacturing cost ........................................................... 105
Tabel 6.8 Total manufacturing cost .................................................................... 106
Tabel 6.9 Total general expense ......................................................................... 106
Tabel 6.10 Total production cost ........................................................................ 106
Tabel 6.11 Fixed cost .......................................................................................... 108
Tabel 6.12 Variable cost ..................................................................................... 109
Tabel 6.13 Regulated cost ................................................................................... 109
Tabel 6.14 Analisis kelayakan ............................................................................ 111
xiii
DAFTAR GAMBAR
Gambar 2.1. Diagram alir kualitatif pabrik asam nitrat dari asam sulfat dan
natrium nitrat kapasitas 65.000 ton/tahun ....................................... 22
Gambar 2.2. Diagram alir kuantitatif pabrik asam nitrat dari asam sulfat dan
natrium nitrat kapasitas 65.000 ton/tahun ........................................ 23
Gambar 2.3 Tata letak pabrik asam nitrat ............................................................. 27
Gambar 2.4. Tata letak peralatan proses pabrik asam nitrat dari asam sulfat
dan natrium nitrat .............................................................................. 30
Gambar 4.1 Denah utilitas prarancangan pabrik asam nitrat ................................ 58
Gambar 5.1 Struktur organisasi perusahaan ......................................................... 85
Gambar 6.1 Hubungan tahun dengan cost index ............................................... 100
xiv
INTISARI
Pabrik asam nitrat dari asam sulfat dan natrium nitrat dengan kapasitas
65.000 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 adiabatic 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 reactor (R-110). Produk keluar dari reactor berupa gas
diembunkan dalam kondensor kemudian dimurnikan di dalam menara distilasi
untuk menghasilkan produk dengan kemurnian 98%, sedangkan hasil bawah
reactor berupa campuran asam nitrat, natrium nitrat, dan natrium bisulfate (niter
cake). Produk asam nitrat yang dihasilkan sebesar 8.207,0707 kg/jam. Unit
pendukung proses terdiri dari unit penyedia air pendingin sebesar 264.779,2772
kg/jam, kebutuhan steam sebesar 19.772,5449 kg/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.
Hasil analisis ekonomi pabrik asam nitrat diperoleh keuntungan sebelum
pajak sebesar Rp113.168.435.407 per tahun, keuntungan setelah pajak sebesar
Rp84.876.326.556. Percent return on investment (ROI) sebelum pajak 34,52%
dan setelah pajak 25,89%. Pay out time (POT) sebelum pajak 2,25 tahun dan
setelah pajak 2,79 tahun. Break event point (BEP) sebesar 47,80%, Shut Down
Point (SDP) sebesar 25,11%, dan Internal Rate of Return (IRR) sebesar 40,27%.
Dari data analisis kelayakan di atas disimpulkan bahwa pabrik ini layak untuk
didirikan.
Kata kunci: Asam nitrat, asam sulfat, niter cake, RATB
xv
ABSTRACT
Nitric acid plant with raw materials of sulphuric acid and sodium nitrate
with a capacity 65.000 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 8,207.0707
kgs/hour. To support the process, utilities are required including 264,779.5449
kgs/hour of cooling water, 19,772.5449 kgs/hour of steam. Which is obtained from
boiler consuming fuel oil as much as 1,473.8109 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
Rp113,168,435,407/year, and Rp84,876,326,556/year after tax. The percent
Return on Investment (ROI) before tax is 34.52% and 25.89% after tax. The Pay
Out Time (POT) before tax is 2.25 years and 2.79 years after tax. The Break
Event Point (BEP), the Shut Down Point (SDP), and the Internal Rate of Return
(IRR) are 47.80, 25.11%, and 40.27%, respectively. The above economic analysis
concludes that the plant is feasible to set.
Keyword: CSTR, niter cake, nitric acid, sulphuric acid