Abstract:The increasing global demand for palm oil and its products has led to a significant growth in palm plantations and palm oil production. Unfortunately, these bring serious environmental problems, largely because of the large amounts of waste material produced, including palm kernel shell (PKS). In this study, we used computational fluid dynamics (CFD) to investigate the PKS co-firing of a 300 MWe pulverized coal-fired power plant in terms of thermal behavior of the plant and the CO 2 , CO, O 2 , NO x , and SO x produced. Five different PKS mass fractions were evaluated: 0%, 10%, 15%, 25%, and 50%. The results suggest that PKS co-firing is favorable in terms of both thermal behavior and exhaust gas emissions. A PKS mass fraction of 25% showed the best combustion characteristics in terms of temperature and the production of CO 2 , CO, and SO x . However, relatively large amounts of thermal NO x were produced by high temperature oxidation. Considering all these factors, PKS mass fractions of 10%-15% emerged as the most appropriate co-firing condition. The PKS supply capacity of the palm mills surrounding the power plants is a further parameter to be considered when setting the fuel mix.

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Co-firing of palm kernel shell (PKS) into 7 MW existing pulverized-coal boiler has been modeled and analyzed using the computational fluid dynamics (CFD). Co-firing of coal and PKS is a complex chemical reaction involving both gas and solid phases with turbulence effect along the combustor. In numerical simulation, two-steps global reaction mechanisms for homogeneous (volatile matter) and heterogeneous (char) combustion, turbulence and radiation heat transfer are considered. Moreover, five different mass fractions of PKS to coal are observed: 0 (fully coal), 10, 15, 25 and 50 %, respectively. In this study, the analysis is focused on the comparative prediction related to the distribution of temperature, velocity and produced gases of CO2, CO, SO2. As the result, higher PKS mass fraction leads to a favorable combustion in terms of combustion temperature and produced gases exhausted from the combustor.

Kondisi kerja internal dan dinamika proses reaktor biogas anaerobik cukup sulitt dipecahkan danbanyak masalah metodologi dalam pemodelan masih harus dipecahkan. Terdapat banyak faktor yangdapat mempengaruhi tingkat pertumbuhan bakteri dan koefisien yield yang mencerminkanpertumbuhan mikroorganisme. Selain itu kurangnya akurasi dalam pengukuran dan kadangkurangnya pengukuran sering mengarah pada masalah identifikasi. Oleh karena itu, modeldikembangkan yang mampu mengkarakterisasi reaktor biogas anaerob menggunakan logika fuzzy.Model ini dibangun menggunakan persamaan keseimbangan massa dan pemodelan beberapaparameter dengan logika fuzzy. Hasil yang diperoleh dibandingkan dengan percobaan yang telahdiakukan pada reaktor fluidized bed dan dengan hasil yang diperoleh dari model lain. Hasil yangdiperoleh cukup baik dalam mengikuti profil hasil eksperimental dan dengan yang diperoleh denganmetode teoritis.Kata kunci: digester anaerobik, logika fuzzy, model reaktor biogas

Biomass utilization to generate electricity via combustion simply can be classified into firing and cofiring. Biomass cofiring into the pulverized coal boilers has some advantages compared to dedicated biomass firing in terms of capital cost and combustion efficiency. To understand the cofiring behavior of biomass and coal comprehensively, computational fluid dynamics (CFD) method can be used to analyze and solve problems involving fluid flows inside a combustor. A CFD modeling is significantly more effective from the perspectives of time and cost and safety and ease of scaling up; hence, it is usually performed before conducting a physical investigation through experiment. Moreover, the current state-of-the-art CFD modeling-based study is capable of solving the complexity of the interdependent processes such as turbulence, heat transfer via radiation, produced gas, and reactions in both the particle and gas phases during combustion. This chapter focuses on the study of cofiring of biomass, which is palm mill wastes, into the existing coal-fired power plant. Two palm mill wastes are evaluated: palm kernel shell and hydrothermally treated empty fruit bunch. Distributions of temperature and the produced are simulated to find the most optimum and applicable cofiring conditions.