Cellulose membrane was produced from bacterial cellulose in the mixture liquid medium by Acetobacterxylinum. The different medium was used including 100% coconut juice (A), 100% sugar palm juice (B) (Arengapinnata), and the mixture liquid medium between 50% coconut juice and 50% sugar palm juice (C). This cellulose membrane was applied for fermented coconut oil as a microfiltration process to determine the ability of cellulose membrane. The goal of this study is to investigate characteristic of fermented coconut oil resulted and physical properties of membrane cellulose, such as the degree of crystallinity by x-ray diffraction (XRD), water content and thermal decomposition behaviour with TGA, scanning electron microscopy analysis (SEM). From different types of cellulose membrane, cellulose membrane C (50% coconut water and 50% sugar palm juice) is the best physical properties for XRD, TGA and SEM. For all cellulose membrane which applied in fermented coconut oil it was reported that it can reduce water content and free fatty acid, but not significantly for refractive index. Cellulose membrane C was also obtained as a better cellulose membrane to increase the quality of fermented coconut oil.
This paper presents results obtained from the application of a computational fluid dynamics (CFD) code Fluent 6.3 to modeling of elevated pressure methane non-premixed sooting flames. The study focuses on comparing the two soot models available in the code for the prediction of the soot level in the flames. A standard k-ε model and Eddy Dissipation model are utilized for the representation of flow field and combustion of the flame being investigated. For performance comparison study, a single step soot model of Khan and Greeves and two-step soot model proposed by Tesner are tested. The results of calculations are compared with experimental data of methane sooting flame taken from literature. The results of the study show that a combination of the standard k-ε turbulence model and eddy dissipation model is capable of producing reasonable predictions of temperature both in axial and radial profiles; although further downstream of the flame over-predicted temperature is evidence. With regard to soot model performance study, it shows that the two-step model clearly performed far better than the single-step model in predicting the soot level in ethylene flame at both axial and radial profiles. With a modification in the constant α of the soot formation equation, the two-step model was capable of producing prediction of soot level closer to experimental data. In contrast, the single-step soot model produced very poor results, leading to a significant under-prediction of soot levels in both flames. Although the Tesner’s soot model is simpler than the current available models, this model is still capable of providing reasonable agreement with experimental data, allowing its application for the purpose of design and operation of an industrial combustion system.
This paper presents results obtained from the application of a computational fluid dynamics (CFD) code Fluent 6.3 to modelling of temperature in propane flames with air preheat. The study focuses on investigating the effect of air preheat temperature on the temperature of the flame. A standard k-ε turbulence model in combination with the Probability Density Function (PDF) model for Non Premix Combustion model and Eddy Dissipation Model (EDM) are utilized to represent the flow and temperature fields of the flame being investigated, respectively. The results of calculations are compared with experimental data of propane flame taken from literature. The results of the study showed that the combination of the standard k-ε turbulence model and PDF model is more capable of producing reasonable predictions of temperature, particularly in axial profile and rich fuel area of all two flames compared with those of EDM model. Both experimental works and numerical simulation showed that increasing the temperature of the combustion air significantly increases the flame temperature.
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