Prarancangan Pabrik Amonium Nitrat (Prill) dari Amonia dan Asam Nitrat melalui Proses UHDE dengan Kapasitas Produksi 290.000 Ton/Tahun

Sarah Rafidah Aziz, Prof. Ir. Indra Perdana, S.T., M.T., Ph.D.

2026 | Skripsi | TEKNIK KIMIA

Amonium nitrat merupakan salah satu produk kimia strategis yang digunakan secara luas sebagai bahan baku pupuk nitrogen dan bahan peledak komersial. Kebutuhan ammonium nitrat di Indonesia terus meningkat, seiring pertumbuhan sektor pertanian dan pertambangan. Namun, kapasitas produksi dalam negeri belum mampu memenuhi permintaan tersebut, sehingga Indonesia masih bergantung pada impor. Oleh karena itu, prarancangan pabrik ammonium nitrat prill dengan kapasitas produksi 290.000 ton/tahun dimaksudkan untuk mengatasi ketergantungan tersebut, sekaligus memperkuat ketahanan pasokan nasional.

Proses produksi di pabrik ammonium nitrat prill didahului dengan proses pembuatan asam nitrat 58% melalui proses Ostwald, yaitu oksidasi amonia dengan katalis Pt-Rh pada suhu 890°C dan tekanan 4,5 atm di reaktor gauze (R-101), dilanjutkan dengan oksidasi NO menjadi NO2 pada suhu 100°C di reaktor oksidasi (R-102), dan absorpsi NO2 dengan air proses dalam kolom absorber (AB-101) bertekanan 11 atm dan suhu 80°C. Asam nitrat yang dihasilkan, selanjutnya digunakan untuk pembuatan amonium nitrat prill melalui proses UHDE. Proses ini dimulai dengan reaksi netralisasi amonia dengan asam nitrat dalam reaktor bubble column (R-201), menghasilkan larutan amonium nitrat berkonsentrasi tinggi yang selanjutnya dipekatkan di double effect evaporator (EV-201), dan dibentuk menjadi prill di prilling tower (PT-301). Setelah dikeringkan di rotary dryer (RD-301) dan ditambahkan coating agent berupa Mg(NO3)2, diperoleh produk akhir berupa amonium nitrat prill dengan kemurnian tinggi. Adapun asam nitrat 58% yang diproduksi melebihi kebutuhan proses, sehingga sebesar 33.378,6937 ton/tahun dijual sebagai produk samping. 

Kebutuhan bahan baku utama adalah amonia 99,5% sebesar 93.226,96 ton/tahun. Kebutuhan utilitas per jam mencakup air baku sebesar 205.479,28 kg/jam, steam sebesar 39.510,73 kg/jam, serta kebutuhan listrik sebesar 51.709,0518 kWh. Pabrik ini direncanakan berlokasi di Kawasan Industri Bontang, Kalimantan Timur, dengan luas lahan 39,95 hektar (399.500 m2) dan luas bangunan 21.041,80 m2. Lokasi dipilih karena kedekatan geografis dengan PT Pupuk Kalimantan Timur selaku pemasok utama amonia. Pabrik beroperasi secara kontinyu 24 jam per hari selama 330 hari per tahun dan mempekerjakan 219 orang karyawan (operator, teknisi, supervisor, engineer, manajemen, serta staf penunjang).

Pembangunan pabrik membutuhkan modal tetap (fixed capital) sebesar USD 163.100.202,85, serta modal kerja (working capital) sebesar USD 35.844.810,79. Berdasarkan evaluasi ekonomi yang telah dilakukan, pabrik ini dinyatakan layak dan menarik untuk didirikan. Nilai Return on Investment (ROI) sebelum pajak sebesar 25,34%, memenuhi standar kelayakan untuk kategori low risk industry, dengan Pay Out Time (POT) sebelum pajak selama 2,91 tahun. Discounted Cash Flow Rate of Return (DCFRR) diperoleh sebesar 13,01% (tanpa pengaruh inflasi) dan 18,11% (dengan pengaruh inflasi), keduanya melampaui nilai MARR sebesar 12%. Break Event Point (BEP) dan Shutdown Point (SDP) berada pada 50,82?n 16,67% kapasitas produksi.

Ammonium nitrate is one of the strategically important chemical commodities widely used as a raw material for nitrogen fertilizers and commercial explosives. Domestic demand for ammonium nitrate in Indonesia continuous to grow alongside expansion in the agricultural and mining sectors; however, existing national production capacity remains insufficient to meet this demand, leaving Indonesia reliant on imports. To address this supply gap and strengthen national supply resilience, a preliminary plant design for ammonium nitrate prill with a production capacity of 290.000 tonnes per year has been developed.

Production at the ammonium nitrate prill plant begins with the manufacture of 58% nitric acid via the Ostwald process, comprising catalytic oxidation of ammonia over a Pt-Rh gauze catalyst (R-101) at 890°C and 4,5 atm, followed by NO oxidation NO2 in an oxidation reactor (R-102) at 100°C, and concluded by absorption of NO2 with process water in an absorber (AB-101) operating at 11 atm and 80°C. The nitric acid produced is subsequently used for ammonium nitrate prill manufacturing via the UHDE process. This process begins with the neutralization of ammonia with nitric acid in a bubble column reactor (R-201), yielding a highly concentrated ammonium nitrate solution, which is then concentrated in a double-effect evaporator (EV-201) and formed into prill in a prilling tower (PT-301). After drying in a rotary dryer (RD-301) and the addition of Mg(NO3)2 as a coating agent, the final product is high-purity ammonium nitrate prill. The nitric acid unit produces 68$ nitric acid more than process requirements, with 33,378.6937 tonnes per year sold as a side product.

The primary raw material requirement is 99,5% liquid ammonia at 93,226.96 tonnes per year. Hourly utility requirements include raw water intake of 205,479.28 kg/hr, steam of 39,510.73 kg/hr, and electrical power of 51,709.05 kW. The plant is planned to be established in the Bontang Industrial Area, East Kalimantan, with a total land area of 39.95 hectares (399,500 m2) and a building area of 21,041.80 m2. The site was selected based on its proximity to PT Kalimantan Timur as the primary ammonia supplier. The plant operates continuously 24 hours per day for 330 days per year and employs approximately 219 personnel (operators, technicians, supervisors, engineers, management, and administrative support staff).

Plant construction requires a fixed capital investment of USD 163,100,202.85 and a working capital of USD 35,844,810.79. Economic evaluation confirms that the plant is feasible and attractive for investment. The before-tax Return on Investment (ROI) of 25,34% satisfies the profitability benchmark for low-risk chemical industries, with a before-tax Pay Out Time (POT) of 2.91 years. The Discounted Cash Flow Rate of Return (DCFRR) is 13.01% (without inflation effect) and 18,11% (with inflation effect), both exceeding the Minimum Acceptable Rate of Return (MARR) of 12%. The Break-Even Point (BEP) and Shutdown Point (SDP) are at 50,82% and 16,67% of production capacity, respectively.

Kata Kunci : Amonium Nitrat, Proses UHDE, Proses Ostwald, Prill, Pupuk Nitrogen