Claim Missing Document
Check
Articles

Found 18 Documents
Search

Auto Regressive eXogenous (ARX) System Identification of Batch Milk Cooling Process Rudy Agustriyanto; Endang Srihari Mochni; Puguh Setyopratomo
ASEAN Journal of Chemical Engineering Vol 22, No 2 (2022)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ajche.70546

Abstract

The dynamic model of the milk cooling process from 36°C to 4°C using chilled water available at 2°C has been carried out.  The cooling water temperature is kept constant by using a refrigeration unit. The process being studied was a Packo brand milk cooling tank belonging to KUD SAE Pujon (Malang - Indonesia). A fundamental heat balance method was used to derive the model, leading to a first-order transfer function process. For a 2 hours cooling process then, the gain and time constant values are 1.00 and 42.3548 mins respectively, or G(s)=1/(42.3548s+1) (first order process). Deriving system transfer function through a mechanistic model is considered difficult; therefore, in this paper, we explored process identification via Auto Regressive eXogenous (ARX). Transient simulations could then be performed to identify the dynamic behavior of the cooling process. The system was then identified using several orders of the Auto Regressive eXogenous (ARX) model, and then the results were re-tested on different forms of perturbations and obtained quite accurate results. The transfer function identified through the ARX111 is G(s)=1/(42.3729s+1) (first order process), while via ARX441, the 5th order process was obtained: G(s)=(0.02361s^4+0.000371s^3+0.2331s^2+9.27×10^(-7) s+0.0005826)/(s^5+0.03932s^4+9.873s^3+0.2331s^2+0.02468s+0.0005826). These models particularly useful for process control design and analysis.
Model of Steady State Cyclohexane Oxidation for Ketone-Alcohol (K-A) Oil Production Agustriyanto, Rudy; Fatmawati, Akbarningrum
Makara Journal of Science Vol. 18, No. 3
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Cylohexane oxidation is of great industrial importance in the production of intermediates for the manufacture of nylon6 and nylon-6,6. Most cyclohexane is commercially converted into a cyclohexanone–cyclohexanol mixture (known as K-A oil) by catalytic oxidation. K-A (Ketone-Alcohol) oil is then used as a raw material for adipic acid and caprolactam production. Practically, if the cyclohexanol content of KA oil is higher than that of cyclohexanone, it is more profitable to convert it into adipic acid; otherwise caprolactam production is more likely. The steady state cyclohexane oxidation reaction model in a stirred tank reactor for K-A oil production is presented and solved in this paper. The model was derived based on the mass balance and mass transfer equations using the kinetic equation. The set of algebraic equations was solved using non linear programming. The advantage of this method is that the relationship among variables can be better understood and an appropriate solution to the equation set can be obtained more quickly. Simulation results are particularly useful for process design such as in determining reactor dimensions and operating conditions.
Process Design of Benzene Nitrification Agustriyanto, Rudy; Sapei, Lanny; Mochni, Endang Srihari; Setyopratomo, Puguh
Keluwih: Jurnal Sains dan Teknologi Vol. 4 No. 1 (2023): Keluwih: Jurnal Sains dan Teknologi (February)
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v4i1.5391

Abstract

Abstract—Aspen HYSYS was used to investigate several aspects of process design for benzene nitration. In this study, the frequency factor (ko) and the activation energy (Ea) for benzene nitration were given from the literature. Calculations of chemical and physical properties were performed automatically on Hysys using the NRTL and UNIQUAC Thermodynamic models. Some aspects of process design were studied, namely: (1) the effect of temperature on the conversion of reactions, (2) the effect of the ratio of sulphuric acid to nitric acid on the synthesis of nitrobenzen in the reactor, and (3) the effect of reactor arrangements ( parallel and series) on reaction conversion. The results showed that the peak of conversion that could be achieved on a single reactor was 96.9% at a ratio of sulfuric acid: nitric acid = 3.5 and a temperature of 50ºC. However, based on this study, it is suggested that the most favorable conditions for nitation of benzene in an isothermal reactor are 50°C and a sulfuric acid:nitric acid ratio of about 2.5 to 3. Abstrak—Aspen HYSYS digunakan untuk menginvestigasi beberapa aspek perancangan proses pada nitrasi benzen. Energi aktivasi (Ea) dan faktor frekwensi (ko) untuk reaksi ini diperoleh dari literature. Perhitungan sifat-sifat fisis dan kimia dilakukan secara otomatis pada Hysys dengan menggunakan model Termodinamik NRTL dan UNIQUAC. Beberapa aspek perancangan proses dipelajari dengan simulasi, yaitu: pengaruh suhu pada konversi reaksi, pengaruh rasio asam sulfat terhadap asam nitrat pada sintesa nitrobenzen dalam CSTR (reaktor berpengaduk kontinyu), dan pengaruh susunan reaktor baik seri maupun parallel terhadap konversi reaksi. Hasil penelitian menunjukkan bahwa konversi tertinggi yang dapat dicapai pada CSTR tunggal adalah 96,9 % pada rasio asam sulfat: asam nitrat = 3,5 dan suhu 50ºC. Namun demikian, berdasarkan penelitian ini, disarankan bahwa kondisi yang paling disukai untuk nitasi benzen dalam CSTR isotermal adalah 50ºC dan rasio asam sulfat:asam nitrat sekitar 2,5 sampai 3.
Simulation of the Hydrodealkylation of Toluene Using Conversion Reactor Agustriyanto, Rudy; Setyopratomo, Puguh; Mochni, Endang Srihari; Purwanto, Edy
Keluwih: Jurnal Sains dan Teknologi Vol. 5 No. 1 (2024): Keluwih: Jurnal Sains dan Teknologi (February) - In Progress
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v5i1.6351

Abstract

Abstract—The hydrodealkylation of toluene is frequently used to produce the more valuable compound benzene. This process is widely employed in the petrochemical industry. Through hydrodealkylation, toluene undergoes a transformation, resulting in the production of valuable chemicals such as benzene and diphenyl. The objective of this study is to present the results obtained from simulating the process of toluene dealkylation using Aspen HYSYS. The feed to the reactor must contain toluene and hydrogen, while the recommended operating conditions are at 500 oC to 650 oC and 20 to 40 atm pressure to achieve 90% conversion. For this purpose, a conversion reactor has been selected as the preferred type. The simulation outcomes are particularly valuable during the initial stages of designing a production facility for benzene. The mass and energy balance calculations can be easily performed using Aspen HYSYS. Future research may focus on investigating different reactor types while considering the kinetics of the reaction. Keywords: aspen HYSYS, hydrodealkylation, simulation, toluene Abstrak—Hidrodealkilasi toluena sering digunakan untuk menghasilkan senyawa yang lebih bernilai yaitu benzene. Proses ini banyak digunakan dalam industri petrokimia. Melalui hidrodealkilasi, toluena mengalami transformasi, menghasilkan bahan kimia berharga seperti benzene dan diphenyl. Tujuan dari penelitian ini adalah untuk menyajikan hasil yang diperoleh dari mensimulasikan proses dealkilasi toluena menggunakan Aspen HYSYS. Umpan ke reaktor harus mengandung toluena dan hidrogen, sedangkan kondisi operasi yang direkomendasikan adalah pada suhu 500 oC hingga 650 oC dan tekanan 20 hingga 40 atm untuk mencapai konversi 90%. Untuk tujuan ini, reaktor konversi telah dipilih sebagai tipe yang disukai. Hasil simulasi sangat berharga selama tahap awal perancangan fasilitas produksi benzene. Perhitungan neraca massa dan energi dapat dengan mudah dilakukan menggunakan Aspen HYSYS. Penelitian masa depan dapat fokus pada penyelidikan berbagai jenis reaktor sambil mempertimbangkan kinetika reaksi. Kata kunci: aspen HYSYS, hidrodealkilasi, simulasi, toluene
Simulasi Pengendali Proporsional Integral pada Proses Penguapan Rudy Agustriyanto
Jurnal Rekayasa Kimia & Lingkungan Vol 12, No 2 (2017): Jurnal Rekayasa Kimia & Lingkungan
Publisher : Chemical Engineering Department, Syiah Kuala University, Banda Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23955/rkl.v12i2.8339

Abstract

Makalah ini mempresentasikan metode penyaringan signal input gradien sehingga dapat meningkatkan kinerja sistem pengendalian bila terjadi gangguan (noise) pada pembacaan sensor. Sistem pengendalian yang dipelajari adalah sistem pengendalian unit penguapan. Cao (2004) telah mempublikasikan suatu strategi pengendalian desentralisasi pada unit operasi penguapan. Keunikan strategi yang diajukan Cao terletak pada perlunya untuk mengendalikan suatu variabel baru yang merupakan fungsi dari data yang berasal dari sensor-sensor yang tersedia. Kondisi optimal pada sistem pengendalian yang ditinjau perlu dijabarkan terlebih dahulu secara matematis dan dinyatakan sebagai gradien yang merupakan fungsi dari berbagai variabel proses. Gradien tersebut kemudian dikendalikan dengan tujuan lebih lanjut untuk mengendalikan variabel sebenarnya. Keuntungan penerapan saringan signal input gradien pada studi ini dinyatakan dalam reduksi biaya operasi yang dibandingkan dengan pengendalian gradien tanpa penyaringan.
Isomerization of Cis-2-Butene to Trans-2-Butene in a Plug Flow Reactor: A Simulation Study Using Aspen HYSYS V14 Rudy Agustriyanto; Endang Srihari Mochni; Edy Purwanto; Puguh Setyopratomo
Keluwih: Jurnal Sains dan Teknologi Vol. 5 No. 2 (2024): Keluwih: Jurnal Sains dan Teknologi (August) - In Progress
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v5i2.6715

Abstract

Abstract—This study investigates the isomerization of cis-2-butene to trans-2-butene in a single-tube Plug Flow Reactor (PFR) using Aspen HYSYS V14 for process simulation. The reaction is modeled as a homogeneous, irreversible isomerization with first-order kinetics (rate constant k=0.003833 s−1). The objective was to determine the optimal reactor volume and channel diameter to achieve 95% conversion of cis-2-butene under specified conditions: 1 meter reactor length, 100 kgmol/h feed rate, 12 bar pressure, and 25°C. The Peng-Robinson fluid package was employed for thermodynamic calculations. Simulation results indicate that a reactor volume of 2.268 m³ and channel diameter of 1.699 m are required to achieve the target conversion. This study demonstrates the efficacy of Aspen HYSYS in reactor design optimization and provides valuable insights for industrial applications of butene isomerization. The methodology presented offers a robust framework for addressing similar chemical engineering challenges. Keywords: aspen HYSYS, butene, isomerization, plug flow reactor, process simulation. Abstrak—Penelitian ini menyelidiki isomerisasi cis-2-butena menjadi trans-2-butena dalam Reaktor Aliran Sumbat (PFR) tabung tunggal dengan menggunakan Aspen HYSYS V14 untuk simulasi proses. Reaksi dimodelkan sebagai isomerisasi homogen irreversible, dengan kinetika orde pertama (konstanta kecepatan reaksi k = 0,003833 s−1). Tujuan penelitian ini adalah menentukan volume reaktor dan diameter saluran yang optimal untuk mencapai konversi cis-2-butena sebesar 95% di bawah kondisi yang telah ditentukan: panjang reaktor 1 meter, laju umpan 100 kgmol/jam, tekanan 12 bar, dan suhu 25°C. Paket fluida Peng-Robinson digunakan untuk perhitungan termodinamika. Hasil simulasi menunjukkan bahwa volume reaktor sebesar 2,268 m³ dan diameter saluran sebesar 1,699 m diperlukan untuk mencapai konversi yang ditargetkan. Penelitian ini menunjukkan efektivitas Aspen HYSYS dalam optimasi desain reaktor dan memberikan wawasan berharga untuk aplikasi industri isomerisasi butena. Metodologi yang dipresentasikan menawarkan kerangka kerja yang kuat untuk mengatasi tantangan rekayasa kimia serupa. Kata kunci: aspen HYSYS, butena, isomerisasi, plug flow reaktor, simulasi proses
Study on the Banana Peel Hydrolysate for Lactic Acid Bacteria Growth Media Akbarningrum Fatmawati; Endang Srihari; Puguh Setyopratomo; Rudy Agustriyanto
Keluwih: Jurnal Sains dan Teknologi Vol. 6 No. 1 (2025): Keluwih: Jurnal Sains dan Teknologi (February) - In Progress
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v6i1.7760

Abstract

Abstract—Banana peel is food waste material that may contain certain beneficial nutrition and be useful for bacterial media production. This experiment aims to determine the effect of several variables which may have influence on the ability of banana peel to support probiotic growth. The thermal treatment used autoclave. In the hydrolysis step for probiotic growth, the variables studied were pH and temperature. The best result of hydrolysis was obtained by the initial steam treatment, followed by hydrolysis process at pH 4.5 and 95oC. The reducing sugar content obtained was 0.96 g/L. In the fermentation process, pure banana peel hydrolysate media was able produces to support Lactobacillus plantarum growth better than mixed media. The pure banana peel hydrolysate media could achieve up to 12.89 log CFU/ml. The amylase activity produced in the pure banana peel hydrolysate media was 8.14 DP. Keywords: banana, probiotic, hydrolysis, growth, amylase Abstrak—Kulit pisang merupakan bahan limbah yang memiliki kandungan nutrisi menguntungkan dan berguna untuk produksi media pertumbuhan bakteri. Penelitian ini bertujuan menentukan pengaruh beberapa variabel yang dapat mempengaruhi kulit pisang untuk mendukung pertumbuhan probiotik. Kulit pisang tersebut diolah melalui hidrolisis enzimatik menggunakan enzim amylase termofilik. Variabel sebelum proses hidrolisis adalah penggunaan pengolahan termal menggunakan uap air dan tanpa pengolahan. Pada langkah hidrolisis, variabel yang dipelajari adalah pH dan suhu. Hasil hidrolisa terbaik adalah dengan penggunaan pengolahan awal dengan uap air diikuti dengan hidrolisis pada pH 4,5 dan suhu 95oC. Kandungan gula pereduksi yang diperoleh sebesar 0,96 g/L. Pada proses fermentasi, media dari hidrolisat kulit pisang murni dapat menghasilkan pertumbuhan Lactobacillus plantarum sampai 12,89 log CFU/mL. Aktivitas amylase yang dihasilkan dari media hidrolisat kulit pisang tersebut adalah 8,14 DP. Keywords: pisang, probiotic, hydrolysis, growth, amylase
Adsorpsi Zat Warna Acid Blue 29 Menggunakan Pristine Multiwalled Carbon Nanotubes Setyopratomo, Puguh; Agustriyanto, Rudy; Yuli Widianto, Aloisiyus; Purwanto, Edy; Srihari, Endang
Keluwih: Jurnal Sains dan Teknologi Vol. 6 No. 2 (2025): Keluwih: Jurnal Sains dan Teknologi (August) - In Progress
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v6i1.7307

Abstract

Abstract—The increasing pollution of dyes in industrial wastewater has recently attracted attention to obtain effective and efficient dye removal techniques. In this study, pristine multiwalled carbon nanotubes were tested for their performance as adsorbents to remove acid blue 29 dye. Multiwalled carbon nanotubes were synthesized by the catalytic chemical vapor deposition method from liquefied petroleum gas with Fe-Co-Mo/MgO catalyst. Adsorption experiments were carried out in batches by varying the initial concentration of dyes. The purpose of this study was to observe the performance of pristine multiwalled carbon nanotubes to adsorb dyes. In addition, observation of the suitability of the adsorption equilibrium model for this system was also carried out. The results showed that pristine multiwalled carbon nanotubes were proven to be able to remove acid blue 29 dye. The experimental results showed that the percentage of dye removal was higher when the initial concentration of dye in the liquid was lower. The pristine carbon nanotubes used were able to reduce dyes from the liquid by 68.8% in just one process cycle. Adsorption equilibrium stu dy showed that Freundlich equilibrium model is more suitable for this system than Langmuir equilibrium model. The results of this study have shown that multiwalled carbon nanotubes have a very good chance as an adsorbent to remove dyes from industrial wastewater. Keywords: adsorption, carbon nanotubes, equilibrium, model, removal Abstrak—Meningkatnya polusi zat warna pada limbah cair industri akhir-akhir ini telah menarik perhatian untuk mendapatkan teknik penghilangan zat warna tersebut yang bekerja secara efektif dan efisien. Pada penelitian ini pristine multiwalled carbon nanotubes diuji kinerjanya sebagai adsorben untuk menghilangkan zat warna acid blue 29. Multiwalled carbon nanotubes disintesa dengan metode catalytic chemical vapor deposition dari liquified petroleum gas dengan katalis Fe-Co-Mo/MgO. Eksperimen adsorpsi dilakukan secara batch dengan memvariasikan konsentrasi awal zat warna. Tujuan penelitian ini adalah untuk menguji kinerja pristine multiwalled carbon nanotubes tersebut untuk mengadsorpsi zat warna. Disamping itu juga dilakukan uji kesesuaian model kesetimbangan adsorpsi untuk sistem ini. Hasil penelitian menunjukkan bahwa pristine multiwalled carbon nanotubes terbukti bisa menghilangkan zat warna acid blue 29. Hasil eksperimen menunjukkan bahwa persen removal zat warna semakin tinggi ketika kosentrasi awal zat warna dalam cairan semakin rendah. Pristine carbon nanotubes yang digunakan mampu menurunkan zat warna dari cairan sebanyak 68,8% dalam satu siklus proses saja. Studi kesetimbagan adsorpsi menunjukan bahwa model kesetimbangan Freundlich lebih sesuai pada sistem ini dibandingkan kesetimbangan model Langmuir. Hasil penelitian ini telah menunjukkan bahwa multiwalled carbon nanotubes memiliki peluang yang sangat bagus sebagai adsorben untuk menghilangkan zat warna dari limbah cair industri. Kata kunci: adsorpsi, carbon nanotubes, kesetimbangan, model, removal