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All Journal ALCHEMY Jurnal Penelitian Kimia Engineering Science Letter
Neni Sintawardani
National Research and Innovation Agency (BRIN)
Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology

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Simulation of Updraft and Downdraft Gasification Using Computational Fluid Dynamics (CFD) for Production of Hydrogen-Rich Syngas from Cow Manure Waste Amaliyah Rohsari Indah Utami; Anindya Nabila Salma; Daffa Rayhan Betha Muchtar; Neni Sintawardani; Suwandi
Engineering Science Letter Vol. 4 No. 03 (2025): Engineering Science Letter
Publisher : The Indonesian Institute of Science and Technology Research

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56741/IISTR.esl.001397

Abstract

Biomass gasification offers a promising route to low‑carbon hydrogen, yet the operating conditions and reactor configuration governing hydrogen-rich syngas remain insufficiently compared across practical regimes. This study aims to quantify the effects of gasifier type (updraft vs. downdraft), operating temperature, and superficial velocity on hydrogen production performance, with emphasis on the syngas H2/CO ratio. Computational fluid dynamics simulations were implemented to model devolatilization, oxidation, and reduction pathways under steady-state assumptions, while systematically varying temperature (680-800°C) and air superficial velocity (0.0025-4 m/s). Model validation against experimental reference data demonstrated good agreement, with relative errors ranging from 5.95% to 6.93%. The results indicate that a downdraft configuration operated at 680°C and 2 m/s maximizes the H2/CO ratio, achieving a value of 2.091, outperforming alternative settings in terms of hydrogen yield and energy efficiency, albeit with higher variability than the updraft configuration. Increasing air flow beyond this optimum diminishes the H2/CO ratio due to enhanced oxidation, whereas raising the temperature to 800°C generally reduces the average H2/CO across both configurations. These findings establish a practical operating window for hydrogen‑rich syngas from livestock waste and highlight the need for rigorous process control to manage variability in downdraft operation. The study provides evidence-based guidance for gasifier design and operation, aiming to achieve efficient and renewable hydrogen production.
Recovery Nutrien dari Efluen Digester Anaerobik Air Limbah Tahu dengan Presipitasi Struvite Zulkarnaini Zulkarnaini; Fenisa Fauziyah Marshal; Puti Sri Komala; Aufa Aniq Rumzi; Dewi Nilawati; Widyarani Widyarani; Diana Rahayuning Wulan; Neni Sintawardani; Nicolaus Nezha Nunez Mahasti
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 2 (2025): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.2.93205.198-223

Abstract

Efluen dari digester anaerobik multistages fixed-bed reactor pengolahan air limbah industri tahu di Desa Giriharja, Kabupaten Sumedang, memerlukan pengolahan lanjut karena masih mengandung nutrien amonium dan fosfor yang melebihi standar baku mutu untuk badan air. Presipitasi struvite merupakan presipitasi kimia yang memungkinkan untuk memperoleh kembali (recovery) amonium dan fosfat dari air limbah dengan cara penambahan magnesium. Air laut dapat digunakan sebagai sumber magnesium untuk proses presipitasi untuk mengurangi biaya operasional. Presipitasi struvite dipengaruhi oleh pH, ion-ion penting, suhu, dan zat-zat asing. Nilai pH yang tinggi dapat meningkatkan efisiensi penyisihan dan recovery P dan N, akan tetapi dapat meningkatkan presipitasi magnesium dan kalsium fosfat sehingga mengurangi kualitas kristal struvite yang terbentuk. Tingkat kejenuhan struvite berbanding lurus dengan logaritma konsentrasi ionik dalam kristal. Tingkat pertumbuhan, jenis dan ukuran kristal dipengaruhi oleh tinggi suhu. Tingginya konsentrasi zat asing pada larutan dapat mengakibatkan terhalangnya pertumbuhan kristal struvite. Penggunaan air laut sebagai sumber magnesium dalam presipitasi struvite dapat mengurangi biaya produksi, transportasi, serta menggantikan penggunaan bahan kimia.Nutrient Recovery from Tofu Wastewater Anaerobic Digester using Struvite Precipitation. Effluent from a multistage anaerobic digestion fixed-bed reactor for tofu industrial wastewater treatment in Giriharja Village, Sumedang Regency, requires further treatment because it still contains nutrients of ammonium and phosphorus that exceed the water quality standards. Struvite precipitation is a chemical precipitation process that allows for the recovery of ammonium and phosphate from wastewater by adding magnesium. Seawater can be used as a source of magnesium for the precipitation process to reduce operational costs. Struvite precipitation is affected by pH, essential ions, temperature, and foreign substances. A high pH value can increase the efficiency of P and N removal and recovery, but it can also increase the precipitation of magnesium and calcium phosphate, thereby reducing the quality of the struvite crystals formed. The level of struvite saturation is directly proportional to the logarithm of the ionic concentration in the crystals. The growth rate, type, and size of crystals are affected by temperature. High concentrations of foreign substances in the solution can inhibit struvite crystal growth. Using seawater as a source of magnesium in struvite precipitation can reduce production and transportation costs and replace the use of chemicals.
Co-Authors Amaliyah Rohsari Indah Utami Anindya Nabila Salma Aufa Aniq Rumzi Daffa Rayhan Betha Muchtar Dewi Nilawati Diana Rahayuning Wulan Fenisa Fauziyah Marshal Nicolaus Nezha Nunez Mahasti Puti Sri Komala Suwandi Widyarani Widyarani Zulkarnaini Zulkarnaini