PYROLYSIS OF MACROALGAE (GRACILARIA SP.) SOLID RESIDUE FROM AGAR INDUSTRY FOR SILICA-RICH BIOCHAR

• Main Author: Helena Isma Putri, Anisa
• Format: Theses
• Language: Indonesia
• Subjects: Teknik kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75952
• Institution: Institut Teknologi Bandung

<p align="justify">Macroalgae is one of the most abundant biomass found in Indonesian waters. Macroalgae Gracillaria sp. is widely used as a raw material in agar production. The production process produces as much as 53% solid by-products that can still be utilized. This research attempts to utilize macroalgae residues to become more valuable materials. Pyrolysis is a thermal decomposition process that can decompose its constituent components into simpler compounds without the presence of oxygen. The products generated through pyrolysis include biochar, which can enhance soil quality and act as an adsorbent, bio-crude oil (BCO) that serves as a potential alternative to fossil fuels, and bio-pyrolysis gas, which can be directly utilized as fuel. The pyrolysis process was carried out by slow pyrolysis at temperatures 300, 400, 500, 600 and 700?C with heating rates of 20, 30, 35 and 40?C/minute. Biochar is the main product with the highest yield of 71.75% at 300?C with a heating rate of 30?C/min. The high recovery of biochar is due to the high ash content in the macroalgae residue. Silica (Si) is a compound frequently present in biochar ash, creating the potential for the formation of a new composite known as silica-char. Biochar with a high silica content provides significant advantages for agriculture, such as its capability to enhance soil fertility, support plant growth, and mitigate the impact of metals in the soil. Biocrude oil yield from the pyrolysis process reached 25% at 700?C with a heating rate of 20?C/min, containing multiple compounds from the carboxylic acid group with a calorific value of 28.8–32.7 MJ/kg. Bio-pyrolysis gas mainly comprised CH4 and H2, suitable as a direct fuel source.