Optimization of Bio-Char Production from Palm Kernel Shells as Metallurgical Coke Using Response Surface Methodology
Abstract
This research focuses on optimizing biochar production from palm kernel shells (PKS) as an environmentally friendly alternative to metallurgical coke. PKS was chosen due to its abundance, high lignocellulose content, and competitive heating value. The conversion process was carried out via pyrolysis at temperatures of 400–700°C with varying residence times. To ensure the biochar produced meets metallurgical coke specifications, this research uses a Response Surface Methodology (RSM) approach with a Central Composite Design (CCD) model to optimize temperature and time parameters. The initial stage involved pre-treatment using water leaching, successfully reducing ash content from 5.68% to 1.25%. Optimization results show that at a temperature of 600–700°C with a residence time of 2–3 hours, the resulting biochar exhibits characteristics that comply with metallurgical coke standards, such as high fixed carbon content (>85%), low ash content (<6%), and a calorific value of 7200 kcal/kg. Moreover, increasing pyrolysis temperature and time also reduces volatile matter and moisture content, resulting in more stable and efficient biochar. This research provides a real solution for utilizing PKS waste as an alternative raw material for the steel industry, reducing dependence on imported coal-based coke. The results of the RSM optimization indicate an optimal temperature of 612°C and a residence time of 3 hours.
References
Alonge, O. I., & Obayopo, S. O. (2023). Optimization study on carbonization of palm kernel shell using response surface method. International Journal of Integrated Engineering, 15(7), 135–144. https://doi.org/10.30880/ijie.2023.15.07.013
Anika, N., Mahardika, M., Panjaitan, J. R. H., Achmad, F., Bindar, Y., Azizah, I. N., Anggraini, R., & Ramadhani, D. A. (2022). Effect of Production Technique on Corncob Biochar Quality. IOP Conference Series: Earth and Environmental Science, 1038(1), 012007.
Babatunde, E. O., Enomah, S., Akwenuke, O. M., Ibeh, M. A., Okwelum, C. O., Mundu, M. M., Adepoju, P. O., Aki, A. O., Oghenejabor, O. D., Adepojua, T. F., Ifedora, C. O., & Majanja, M. K. (2025). Preparation and characterization of Palm Kernel Shell (PKS) based biocatalyst for the transformation of kernel oil to biodiesel. South African Journal of Chemical Engineering, 52(1). https://hdl.handle.net/10520/ejc-chemeng-v52-n1-a19
Badan Pengelola Dana Perkebunan (BPDP). (2025). Peran strategis perkebunan sawit rakyat di Indonesia. https://www.bpdp.or.id/peran-strategis-perkebunan-sawit-rakyat-di-indonesia
Bushra, B., & Remya, N. (2024). Biochar from pyrolysis of rice husk biomass—characteristics, modification and environmental application. Biomass Conversion and Biorefinery, 14, 5759–5770. https://doi.org/10.1007/s13399-020-01092-3
Chee, A. L. K., Chin, B. L. F., Goh, S. M. X., Chai, Y. H., Loy, A. C. M., Cheah, K. W., Yiin, C. L., & Lock, S. S. M. (2023). Thermo-catalytic co-pyrolysis of palm kernel shell and plastic waste mixtures using bifunctional HZSM-5/limestone catalyst: Kinetic and thermodynamic insights. Journal of the Energy Institute, 107, 101194. https://doi.org/10.1016/j.joei.2023.101194
Chelladurai, S. J. S., Murugan, K., Ray, A. P., Upadhyaya, M., Narasimharaj, V., & Gnanasekaran, S. (2021). Optimization of process parameters using response surface methodology: A review. Materials Today: Proceedings, 37(2), 1301–1304. https://doi.org/10.1016/j.matpr.2020.06.466
Chen, D., Zhuang, X., Gan, Z., Cen, K., Ba, Y., & Jia, D. (2022). Co-pyrolysis of light bio-oil leached bamboo and heavy bio-oil: Effects of mass ratio, pyrolysis temperature, and residence time on the biochar. Chemical Engineering Journal, 437 (Part 1), 135253. https://doi.org/10.1016/j.cej.2022.135253
Cueva, L. L. Z., Griffin, G. J., Ward, L. P., Madapusi, S., Shah, K. V., & Parthasarathy, R. (2022). A study of chemical pre-treatment and pyrolysis operating conditions to enhance biochar production from rice straw. Journal of Analytical and Applied Pyrolysis, 163, 105455. https://doi.org/10.1016/j.jaap.2022.105455
Guo, Y., Wang, X., & Deng, K. (2024). The road to carbon neutrality in the metallurgical industry: Hydrogen metallurgy processes represented by hydrogen-rich coke oven gas, short-process metallurgy of scrap and low-carbon policy. In Journal of Physics: Conference Series (Vol. 2798, 012053). IOP Publishing. https://doi.org/10.1088/1742-6596/2798/1/012053
Hassan, N., Abdullah, R., Khadiran, T., et al. (2023). Biochar derived from oil palm trunk as a potential precursor in the production of high-performance activated carbon. Biomass Conversion and Biorefinery, 13, 15687–15703. https://doi.org/10.1007/s13399-021-01797-z
Jamilatun, S., Mufandi, I., Budiman, A., & Suhendra, S. (2020). Biochar from slow catalytic pyrolysis of spirulina platensis residue: Effects of temperature and silica-alumina catalyst on yield and characteristics. Jurnal Rekayasa Proses, 14(2), 137–147.
Khitab, A., Ahmad, S., Khan, R. A., Arshad, M. T., Anwar, W., Tariq, J., Khan, A. S. R., Khan, R. B. N., Jalil, A., & Tariq, Z. (2021). Production of biochar and its potential application in cementitious composites. Crystals, 11(5), 527.
Liao, W., Zhang, X., Ke, S., Shao, J., Yang, H., Zhang, S., & Chen, H. (2022). Effect of different biomass species and pyrolysis temperatures on heavy metal adsorption, stability and economy of biochar. Industrial Crops and Products, 186, 115238. https://doi.org/10.1016/j.indcrop.2022.115238
Liu, M., Shen, Z., Liang, Q., Xu, J., & Liu, H. (2018). New slag–char interaction mode in the later stage of high ash content coal char gasification. Energy & Fuels, 32(11), 11335–11343.
Lu, X., & Gu, X. (2022). A review on lignin pyrolysis: Pyrolytic behavior, mechanism, and relevant upgrading for improving process efficiency. Biotechnology for Biofuels, 15, 106. https://doi.org/10.1186/s13068-022-02203-0
Onokwai, A. O., Okokpujie, I. P., Ajisegiri, E. S. A., Oki, M., Onokpite, E., Babaremu, K., & Jen, T.-C. (2023). Optimization of pyrolysis operating parameters for biochar production from palm kernel shell using response surface methodology. Mathematical Modelling of Engineering Problems, 10(3), 757. https://doi.org/10.18280/mmep.100304
Mariyam, S., Alherbawi, M., Pradhan, S., et al. (2024). Biochar yield prediction using response surface methodology: Effect of fixed carbon and pyrolysis operating conditions. Biomass Conversion and Biorefinery, 14, 28879–28892. https://doi.org/10.1007/s13399-023-03825-6
Rahman, M. S., Haque, M. E., & Noman, M. R. A. F. (2020). An overview of biochar production and biochar producing stoves in Bangladesh. International Journal of Science and Management Studies (IJSMS), 14–31.
Raza, M., & Abu-Jdayil, B. (2023). Synergic interactions, kinetic and thermodynamic analyses of date palm seeds and cashew shell waste co-pyrolysis using Coats–Redfern method. Case Studies in Thermal Engineering, 47, 103118. https://doi.org/10.1016/j.csite.2023.103118
Raza, M., Inayat, A., Ahmed, A., Jamil, F., Ghenai, C., Naqvi, S. R., Shanableh, A., Ayoub, M., Waris, A., & Park, Y.-K. (2021). Progress of the pyrolyzer reactors and advanced technologies for biomass pyrolysis processing. Sustainability, 13(19), 11061.
Safarian, S. (2023). To what extent could biochar replace coal and coke in steel industries? Fuel, 339, 127401. https://doi.org/10.1016/j.fuel.2023.127401
Sajdak, M., Muzyka, R., Gałko, G., Ksepko, E., Zajemska, M., Sobek, S., & Tercki, D. (2023). Actual trends in the usability of biochar as a high-value product of biomass obtained through pyrolysis. Energies, 16(1), 355. https://doi.org/10.3390/en16010355
Sarker, T. R., Ethen, D. Z., & Nanda, S. (2024). Decarbonization of metallurgy and steelmaking industries using biochar: A review. Chemical Engineering & Technology. https://doi.org/10.1002/ceat.202400217
Sharma, N., & Tiwari, H. P. (2024). Sustainable cokemaking technology: Future needs for ironmaking. Coke and Chemistry, 67, 210–223. https://doi.org/10.3103/S1068364X24701321
Usino, D. O., Sar, T., Ylitervo, P., & Richards, T. (2023). Effect of acid pretreatment on the primary products of biomass fast pyrolysis. Energies, 16(5), 2377. https://doi.org/10.3390/en16052377
Vasudev, V., Ku, X., & Lin, J. (2021). Combustion behavior of algal biochars obtained at different pyrolysis heating rates. ACS Omega, 6(29), 19144–19152.
Viegas, C., Nobre, C., Correia, R., Gouveia, L., & Gonçalves, M. (2021). Optimization of biochar production by co-torrefaction of microalgae and lignocellulosic biomass using response surface methodology. Energies, 14(21), 7330. https://doi.org/10.3390/en14217330
Qing, H., Shagali, A. A., Mostafa, M. E., Hu, S., Xu, K., Xu, J., Jiang, L., Wang, Y., Su, S., & Xiang, J. (2025). Nonlinear mechanism of carbon dioxide on the release of volatile matter from bituminous coal combustion at high heating rate. Fuel, 398, 135531. https://doi.org/10.1016/j.fuel.2025.135531
Wang, B., Li, C., & Cao, W. (2021). Effect of polyacrylonitrile precursor orientation on the structures and properties of thermally stabilized carbon fiber. Materials, 14(12), 3237.
Wang, H., Zhou, P., & Zhao, X. (2025). Applications of biochar in fuel and feedstock substitution: A review. Energies, 18(17), 4511. https://doi.org/10.3390/en18174511
Wang, L., Yang, Y., Ou, Y., Dong, Y., Zhong, Q., Zhang, Y., Li, Q., Huang, Z., & Jiang, T. (2024). Enhancement of coal tar pitch carbonization with biochar: A metallurgical formed biocoke product produced by waste coke breeze and bamboo powder. Fuel, 358(Part B), 130238. https://doi.org/10.1016/j.fuel.2023.130238
Wang, S., Yu, S., Feng, T., Li, W., & Zhang, R. (2025). Life cycle environmental impacts based on detailed stages and synergistic environmental benefits of coke production in China. Journal of Environmental Chemical Engineering, 13(5), 117527. https://doi.org/10.1016/j.jece.2025.117527
Zhang, C., Chao, L., Zhang, Z., Zhang, L., Li, Q., Fan, H., Zhang, S., Liu, Q., Qiao, Y., Tian, Y., Wang, Y., & Hu, X. (2021). Pyrolysis of cellulose: Evolution of functionalities and structure of bio-char versus temperature. Renewable and Sustainable Energy Reviews, 135, 110416. https://doi.org/10.1016/j.rser.2020.110416
Zulkafli, A. H., Hassan, H., Ahmad, M. A., et al. (2024). Co-pyrolysis of palm kernel shell and polypropylene for the production of high-quality bio-oil: Product distribution and synergistic effect. Biomass Conversion and Biorefinery, 14, 13391–13406. https://doi.org/10.1007/s13399-022-03476-z
