Papers by stefanus Muryanto
E3S Web of Conferences, 2021
The purpose of this study was to study the growth of struvite crystals from the effect of adding ... more The purpose of this study was to study the growth of struvite crystals from the effect of adding tartaric acid additives to an aqueous solution containing Mg2+, NH4+, and PO43-with a molar ratio of 1:1:1. The results of the study, it was found that the more the concentration of tartaric acid additive was added, it got smaller the rate constant was. By decreasing the value of the constant rate, the growth of struvite crystals also decreased then the growth of struvite crystals became inhibited. On the other hand, struvite has the potential to be used as a fertilizer. The concentration of tartaric acid also had a significant effect on controlling the production of struvite. The optimum crystal mass was obtained at a concentration of 20 ppm tartaric acid, a temperature of 40oC and a stirrer rotation of 300 rpm so that it can be applied in manufacture industry of struvite fertilizer.
Kerak merupakan masalah yang cukup serius yang dijumpai pada sebagian besar proses industri, yai... more Kerak merupakan masalah yang cukup serius yang dijumpai pada sebagian besar proses industri, yaitu terjadinya pengendapan garam pada dinding-dinding peralatan proses aliran fluida, terutama pada permukaan transfer panas dan permukaan alat-alat evaporasi. Kerak yang menumpuk pada pipa-pipa saluran, lubang-lubang dan beberapa bagian aliran pada proses aliran fluida dapat menyebabkan gangguan yang serius pada pengoperasian, karena penumpukan kerak ini dapat mengakibatkan terjadinya korosi dan kerusakan pada peralatan proses produksi. Dalam penelitian ini dilakukan eksperimen tentang CaCO3 dalam pipa uji dengan membuat larutan dari CaCl2 dan NaCO3 dengan konsentrasi larutan masing-masing 3500 ppm, 4000 ppm dan 4500 ppm dengan laju alir 30 ml/menit pada temperatur kamar. Zat aditive yang digunakan adalah asam malat dengan konsentrasi 3 dan 5 ppm. Kata kunci : asam malat, kalsium karbonat, konsentrasi larutan
Advanced Science Letters, 2017
Advanced Science Letters, 2017
Journal of Physics: Conference Series, 2019
Chemical engineering education can be aptly structured on four central components: macroscopic, p... more Chemical engineering education can be aptly structured on four central components: macroscopic, particulate, symbolic, and human element domains; known as the Mahaffy’s tetrahedral concept. This paper discusses the application of the concept of undergraduate chemical engineering capstone projects. The capstone was carried out as an undergraduate final laboratory project to investigate the adsorption of heavy metal, namely cadmium (Cd), using powder of teak leaves (Tectona grandis sp.). The lab experiment was environmentally safe, completed at ambient temperatures and that the experimental data collection was easy. It was actively guided by lecturers in a way to encourage meaningful lab experience as proposed in the Mahaffy’s tetrahedral idea. Three experimental variables were investigated: initial pH solution, adsorbent dosage, and initial concentration of Cd. The results were analyzed to determine the diffusion mechanism and kinetics through Weber-and-Morris intra-particle diffusio...
Materials Today: Proceedings, 2019
The influence of frequency 5,000 Hz, 2,000 Gauss sawtooth wave of solenoid magnetic field in the ... more The influence of frequency 5,000 Hz, 2,000 Gauss sawtooth wave of solenoid magnetic field in the kinetic aspect of 3,500 ppm CaCO 3 solution on scale formation in piping system was investigated. Citric acid (C 6 H 8 O 7) 5; 10 ppm was added to inhibit the scale in house experimental rig which completed by computer program to control the flow rate at 30 ml/minute, temperature at 30; 40; 50 0 C. The Induction times were found as 16; 14 and 12 minutes and the deposition rates were found as 0.0625; 0.0735 and 0.0896 gr/hr. Using SEM shows that the phases mostly vaterite, aragonite and some of calcite.
In the current research, the influence of frequency 10; 100; 1000 Hz square wave of solenoid magn... more In the current research, the influence of frequency 10; 100; 1000 Hz square wave of solenoid magnetic field on CaCO 3 scale formation in piping system was investigated. CaCO 3 scale was synthesized by CaCl 2 .2H 2 O and Na 2 CO 3 in the stoichiometry calcium solution was set at 3,500 ppm To inhibit the scale, citric acid (C 6 H 8 O 7) was added to calcium solution in meager degree, i.e. 5.00 and 10.00 ppm. This experiment was conducted by in house experimental rig completed by computer program to control the experiment parameters,flow rate at 30 ml/minute ;temperature at 30 0 C. Induction time was found as 17; 16 and 13 minute for the experiment of 10:100:1000 Hz respectively. Deposition rate was found as 0.0525; 0.0655 and 0.0790gr/hr for the experiment of 1,000 Gauss respectively. The polymorph of the scale was characterized by SEM to investigate the morphology of the crystal phases through shape and dispersion method. The result shows that vaterite predominates the phases.
Advanced Science Letters, 2018
In many industries, mechanical equipment such as a turbine, compressor, blower, mixer, extruder c... more In many industries, mechanical equipment such as a turbine, compressor, blower, mixer, extruder can generate a vibration in the pipe present around this equipment. In this paper, the influence of vibration on a piping flowwater system with BaSO 4 scale formation was investigated for understanding the role of vibration on scale formation. Crystalline powder of BaCl 2 • 2H 2 O and Na 2 SO 4 (Merck) was selected to synthesize BaSO 4 scale formation. EDTA was selected as antiscalant reagent. The results showed that the pure barite with a plate-like morphology was grown under non-vibrating and vibrating pipe.
Education for Chemical Engineers, 2017
Abstract Crystallization was carried out as one of the undergraduate chemical engineering lab pro... more Abstract Crystallization was carried out as one of the undergraduate chemical engineering lab projects. The crystallization lab conveyed concepts of crystallization fundamentals, i.e. crystallization rates, crystal growth and morphology. Specifically, it was designed to develop insights on how to relate the crystallization rates with the change in pH level. The experiment was environmentally safe, done at ambient temperatures and thus energy-efficient, and that the experimental data collection was easy. The experiment was actively guided by lecturers in a way to encourage meaningful lab experience. Analysis of the data involved straightforward mathematical expressions and graph plotting using familiar software. A typical of the lab projects, namely crystallization of magnesium ammonium phosphate hexahydrate (MgNH 4 PO 4 ·6H 2 O), commonly known as struvite, is presented in this paper, of which the experimental results agreed with most published literature. The project was implemented in accordance with aspects of good laboratory practice, i.e. in alignment with content, assessment, and pedagogy. To assess learning outcomes, pre- and post-evaluation instruments were employed. The post-test scores were significantly higher than those of the pre-test indicating that the learning outcomes were achieved. Students’ overall feedback was positive, implying that the lab projects have been successfully implemented. In addition, the lab projects were found to increase students’ writing and presentation skills.
Pengerakan (scaling) merupakan masalah yang kompleks dan selalu terjadi di dalam suatu industri. ... more Pengerakan (scaling) merupakan masalah yang kompleks dan selalu terjadi di dalam suatu industri. Terjadinya kerak karena proses alami adanya reaksi kimia antara kandungan-kandungan yang tidak dikehendaki yang terlarut di dalam air seperti: Ca2+, SO4-2, CO3-2dan Mg2+. Gipsum (CaSO4.2H2O) adalah salah satu komponen utama dari kerak yang banyak dijumpai. Akibat adanya pengerakan ini akan merugikan yaitu mempertebal dinding pipa yang dilewati cairan dan dapat mempengaruhi laju aliran ataupun perpindahan panas. Oleh karena harus dilakukan pencegahan untuk menghambat pertumbuhan kerak dalam pipa tersebut. Dalam penelitian ini dilakukan eksperimen tentang pertumbuhan kerak gipsum dalam pipa uji, dengan mereaksikan CaCl2 dan Na2SO4 dengan laju alir 30 ml/menit dan konsentrasi larutan 3500 ppm, Ca2+. Fe2+ ditambahkan kedalam larutan sebagai impuritas. Adapun pipa uji berisi empat pasang kupon terbuat dari kuningan karena tahan terhadap korosi. Pembentukan kristal gipsum dapat dilihat da...
Jurnal Inovasi Teknik Kimia
Fermentasi buah nanas melalui proses hidrolisa dapat menghasilkan alkohol dan hasil samping berup... more Fermentasi buah nanas melalui proses hidrolisa dapat menghasilkan alkohol dan hasil samping berupa ampas yang dapat digunakan sebagai pakan ternak. Alkohol yang dihasilkan dapat digunakan sebagai bahan pelarut obat – obatan, kosmetik maupun sebagai bahan minuman seperti anggur. Tujuan dari penelitian ini untuk mempelajari variabel yang berpengaruh secara signifikan dan tidak signifikan serta kondisi optimal yang dapat diperoleh selama fermentasi kulit buah nanas menggunakan ragi sacharomyces cereveceae. Metode yang digunakan dalam perancangan penelitian yaitu metode Box-Bhenken Design dan menggunakan analisa Response Surface Methodology untuk menghitung hasil penelitian. Dari hasil penelitian diketahui bahwa variabel yang berpengaruh secara signifikan yaitu % starter, sedangkan variabel waktu dan pH tidak berpengaruh secara signifikan. Kadar alkohol yang dihasilkan yaitu 3,83304 dengan kondisi optimal pada waktu 48,6370 jam, pH 5,3182 dan 14,5910 % yeast .
Heliyon, 2022
This article provides an alternative competency test model for vocational education schools in Ce... more This article provides an alternative competency test model for vocational education schools in Central Java, Indonesia which particularly for automotive skill competency in order to replace the current competency test model that has been implemented for several decades which the author's concern about the students' accomplishment during the competency test, aimed to improve competency test results to increase the students' job opportunity in the labor market. Currently, the applied competency test model is the 'Continuity' model, where the students are given five tasks and should be finished within five hours with limited break time. This model tends to increase students' fatigue and stress levels. Consequently, the students lose their focus and concentration which adversely impacts their competency test results. In this study, the new competency test model namely the 'Discontinuity' competency test model was proposed aiming to overcome the issue of the 'Continuity' model. To research the effect of the 'Discontinuity' model implementation on the students' competency test results and vocational school competency test management, a study was done among 100 students and 50 teachers in 10 vocational education schools around Central Java, Indonesia. The results show that the 'Discontinuity' competency test model gives a significant improvement in the students' competency test scores. This reasonably happened due to the implementation of the 'Discontinuity' model gives the students time to break for an hour of each competency task. Without this break time, fatigue and stress levels of the students will significantly increase which adversely affect the students' competency final score. In addition, the new management of the competency test was proposed in this research.
International Journal of Engineering and Advanced Technology, 2020
Scale formation of BaSO4 (barite) is a serious and persistent problem in a petroleum industry. Th... more Scale formation of BaSO4 (barite) is a serious and persistent problem in a petroleum industry. The scale may severely hamper industrial processes through clogging the equipment, blocking the piping system, reducing the transfer of heat and material, which can lead to total breakdown and substantial financial losses. Hence, various methods have been applied to prevent the scaling of barite. This work reports a vibrated-batch lab crystallization to examine the influence of copper oxide (CuO) and zinc oxide (ZnO), an increasing temperature and mechanical vibration at 4.00 Hz and 8.00 Hz frequencies on crystallization kinetics and morphology of barite. The experiments using an experimental rig which was equipped with mechanical vibration to vibrate the rig under the heating program control. The inducing of vibration at 4.00 Hz and 8.00 Hz frequencies resulted in increasing rate scale deposition, whereas barite is the main crystal of the precipitated product which could be validated by t...
ASEAN Journal of Chemical Engineering, 2005
The formation of scales in pipes and on the surfaces of vessels is one of the major problems enco... more The formation of scales in pipes and on the surfaces of vessels is one of the major problems encountered by the mineral processing industry in Australia and elsewhere. A cursory study revealed that one of the main components of the scales was gypsum or calcium sulfate dihydrate. This paper discusses a typical undergraduate laboratory project to investigate the formation of calcium sulfate dihydrate scale on the surfaces of different types of pipes under isothermal conditions. This laboratory exercise is essentially a crystallization process and is suggested as one of the topics for final-year chemical engineering undergraduate project since it is a very important unit operation in the chemical, mineral, or pharmaceutical industries. Keywords: Calcium sulfate dihydrate, laboratory project, scale formation, and undergraduate curriculum..
Journal of Science & Science Education, 2017
Excessive input of N and P into water bodies causes eutrophication which leads to deterioration o... more Excessive input of N and P into water bodies causes eutrophication which leads to deterioration of aquatic evironments and has adverse effects naturally and economically. It is therefore urgent to remove N and P from wastewater prior to disposal into inland and coastal waters. Among the various removal methods, controlled struvite precipitation is preferred. Struvite (MgNH4PO4.6H2O) precipitates uncontrollably under the specific conditions producing a scale deposit causing persistent problems in industries and wastewater treatment plants. The scale deposit clogs the piping system and impair plant equipment. On the other hand, thanks to its composition and properties, struvite is a potential fertilizer. In medical field, struvite is a common component of kidney stones. A number of process parameters govern the struvite precipitation. This paper briefly presents these parameters: pH, molar ratios, temperature, mixing, and presence of foreign ions. pH level is considered as the most im...
REAKTOR, 2017
This paper descripbes a study on the effects of admixtures on the crystallization rate of gypsum.... more This paper descripbes a study on the effects of admixtures on the crystallization rate of gypsum. Two different types of biodegradable admixtures commonly used as flotation agent in copper/zinc concentrate production, namely, sodium isopropyl xanthate (=SIPX) and isopropyl thionocarbamate were investigated in this study. A laboratory batch crystallizer was used in this study, and the experiments were run using seeded method. The rate of desupersaturation or the time required to reach the equilibrium concentration was compared for varying admixture oncentrations. It was discovered that the added seed crystals started growing imediately upon addition into the supersaturated solution, i.e. there was no induction time.Results of this batch crystallizationstudy suggest that addition of admixtures individually or in combination, significantly affects the crystallization kinetics and in particular, reduces the rate of crystallization of gypsum. Activation energies were determined using t...
IOP Conference Series: Materials Science and Engineering, 2016
Adsorption laboratory experiment for undergraduate chemical engineering program is discussed. The... more Adsorption laboratory experiment for undergraduate chemical engineering program is discussed. The experiment demonstrated adsorption of copper ions commonly found in wastewater using bio-sorbent, i.e. agricultural wastes. The adsorption was performed in a batch mode under various parameters: adsorption time (up to 120 min), initial pH (2 to 6), adsorbent dose (2.0 to 12.0 g L-1), adsorbent size (50 to 170 mesh), initial Cu2+ concentration (25 to 100 ppm) and temperatures (room temp to 40°C). The equilibrium and kinetic data of the experiments were calculated using the two commonly used isotherms: Langmuir and Lagergren pseudo-first-order kinetics. The maximum adsorption capacity for Cu2+ was found as 94.34 mg g-1. Thermodynamically, the adsorption process was spontaneous and endothermic. The calculated activation energy for the adsorption was observed as high as 127.94 kJ mol-1. Pedagogically, the experiment was assumed to be important in increasing student understanding of kinetic, equilibrium and thermodynamic concepts.
Scale formation is one of the persistent problems in mineral processing and related industries. O... more Scale formation is one of the persistent problems in mineral processing and related industries. One of the main components of the scale is frequently gypsum or calcium sulphate dihydrate (= CaS04.2H20). Gypsum is formed through the process of crystallisation, and it is well known that crystallisation process is significantly affected by the presence of admixtures. Industrially, scale formation occurs in an environment which is very rarely free from the presence of admixtures. In a typical mineral processing industry, certain types of admixtures are present, which may include metallic ions (e.g. originated from corrosion products) and certain types of the flotation agents used. The effect of admixtures on crystallisation kinetics and cyclical morphology can be very significant, even if they are present in trace amounts. It is important to emphasise that the effects are generally specific, that there is no unified theory that applies to all and every situation. The present study has i...
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Papers by stefanus Muryanto